WO2023167485A1 - Method for controlling yaw of vehicle - Google Patents

Method for controlling yaw of vehicle Download PDF

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Publication number
WO2023167485A1
WO2023167485A1 PCT/KR2023/002779 KR2023002779W WO2023167485A1 WO 2023167485 A1 WO2023167485 A1 WO 2023167485A1 KR 2023002779 W KR2023002779 W KR 2023002779W WO 2023167485 A1 WO2023167485 A1 WO 2023167485A1
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WIPO (PCT)
Prior art keywords
steering
control
over
yaw
under
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PCT/KR2023/002779
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French (fr)
Korean (ko)
Inventor
이정일
임창희
조준우
최동휘
김법식
김시현
Original Assignee
이래에이엠에스 주식회사
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Publication of WO2023167485A1 publication Critical patent/WO2023167485A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K31/00—Vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed, i.e. preventing speed from exceeding an arbitrarily established velocity or maintaining speed at a particular velocity, as selected by the vehicle operator
    • B60K31/12—Vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed, i.e. preventing speed from exceeding an arbitrarily established velocity or maintaining speed at a particular velocity, as selected by the vehicle operator including a device responsive to centrifugal forces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/18—Conjoint control of vehicle sub-units of different type or different function including control of braking systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W10/00—Conjoint control of vehicle sub-units of different type or different function
    • B60W10/20—Conjoint control of vehicle sub-units of different type or different function including control of steering systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W30/00—Purposes of road vehicle drive control systems not related to the control of a particular sub-unit, e.g. of systems using conjoint control of vehicle sub-units
    • B60W30/02—Control of vehicle driving stability
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
    • B60W40/02—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to ambient conditions
    • B60W40/06—Road conditions
    • B60W40/068—Road friction coefficient
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
    • B60W40/10—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to vehicle motion
    • B60W40/114—Yaw movement

Definitions

  • the present invention relates to electronic stability control of a vehicle, and more particularly to a method for controlling oversteer and understeer.
  • Driving stability of a vehicle is improved through electronic stability control (ESC) of the vehicle, and as an example, control corresponding to oversteer caused by excessive steering is performed.
  • ESC electronic stability control
  • the method of stabilizing the yaw rate through speed reduction is also important, but when the speed reduction method cannot be used or in a situation where it is difficult to reduce speed, it can bring relatively better results in terms of steering feel or driving performance than the method through speed control.
  • An effective yaw control method is required.
  • An object of the present invention is to provide a yaw control method capable of following and reflecting a driver's steering intention while maintaining vehicle stability.
  • a method for controlling yaw of a vehicle includes the steps of setting oversteering reference values and understeering reference values for a high-friction road surface and oversteering reference values and understeering reference values for a low-friction road surface, respectively; Determining whether over-steering or under-steering is based on the information, the over-steering reference value, and the under-steering reference value, and if it is determined that the over-steering or under-steering ratio while maintaining the same phase as the predetermined limit yaw rate and controlling the yaw rate according to the adjusted limited threshold yaw rate.
  • the excessive steering reference value and the understeering reference value may each include one or more reference values of a steering angle, a steering angular velocity, a lateral acceleration, a difference between a target yaw rate and an actual yaw rate, and a variation thereof.
  • a method for controlling yaw of a vehicle controls a plurality of control elements for controlling braking of each wheel to cross each other for over/under steer control when it is determined that the oversteering or understeering is performed. It may further include the step of performing crossover control.
  • the crossing control may be performed by dividing into a plurality of crossing sections, and the information for stability control of the crossing section may be transmitted to the next crossing section and used.
  • the crossing section may be designed to increase in overall size as a switching operation occurs due to excessive steering.
  • the information for stability control of the crossing section may include yaw rate information and proportional derivative information.
  • a method for controlling yaw of a vehicle includes the steps of setting oversteering reference values and understeering reference values for a high-friction road surface and oversteering reference values and understeering reference values for a low-friction road surface, respectively, related to the yaw of the vehicle. Determining whether over-steering or under-steering is based on driving information, the over-steering reference value, and the under-steering reference value, and a limited limit yaw rate obtained by adjusting a predetermined limit yaw rate when it is determined that the over-steering or under-steering is the case.
  • yaw control that can follow and reflect the driver's steering intention while maintaining vehicle stability can be achieved.
  • 1 is a graph showing steering characteristics according to a steering angle and vehicle speed of a vehicle.
  • FIG. 3 is a flowchart of a process for determining over/under steering of a method for controlling yaw of a vehicle according to an embodiment of the present invention.
  • FIG. 5 is a graph showing oversteer control with a limited target yaw rate according to an embodiment of the present invention.
  • FIG. 6 is a graph showing control of a rate change of a limited target yaw rate according to an embodiment of the present invention.
  • FIG. 7 is a graph showing an example of a dynamic change of a dynamic limited target yaw according to over/under steering determination according to an embodiment of the present invention.
  • FIG. 8 is a graph showing a control for minimizing urine according to a switching mechanism according to an embodiment of the present invention.
  • FIG. 9 shows a graph showing an example of a possible form of a crossing control section according to an embodiment of the present invention.
  • FIG. 10 is a graph showing a flexible control form of set values of a solenoid valve and a motor in an intersection section of a dual structure type according to an embodiment of the present invention.
  • FIG. 11 is a flow chart of a switching mechanism for controlling a cross section of a dual structure type according to an embodiment of the present invention.
  • FIG. 12 is a graph showing control for each section based on yaw rate information for each step in a dual structure according to an embodiment of the present invention.
  • FIG. 13 is a graph showing the shape of the lateral/lateral front and rear wheel pressures in an intersection section according to situations before and after switching according to an embodiment of the present invention.
  • FIG. 14 is a flowchart showing a process of setting a limited target yaw and controlling intersection in a method for controlling yaw of a vehicle according to an embodiment of the present invention.
  • 15 is a graph showing a result of yaw rate control after sudden changeover steering by a control method according to an embodiment of the present invention.
  • 16 is a graph showing a result of yaw rate control through a sinusoidal road limit yaw and a switching mechanism according to an embodiment of the present invention.
  • the main purpose of electronic stability control (ESC) of a vehicle is to secure vehicle stability, and while giving priority to stability, steering and driving performance are also considered.
  • ESC electronic stability control
  • a phenomenon in which the vehicle spins out may occur with a turning radius much smaller than a driver's requested or desired turning radius.
  • the turning speed of the vehicle is much smaller than the turning speed for the desired turning radius and course, a plow phenomenon in which the vehicle is pushed while drifting may occur.
  • the former case and the latter case can be referred to as oversteer and understeer, and excessive or insufficient turning speed can be understood as the yaw moment of the vehicle.
  • vehicle steering characteristics may be represented by a graph having two axes, a tire angle and a vehicle speed.
  • the characteristic speed (V ch ) means the vehicle speed corresponding to twice the Ackerman angle, which is the required steering angle to maintain it when turning, and the critical speed is the vehicle's behavior in an oversteer situation. Indicates the rate of instability.
  • the vehicle's characteristic speed corresponds to the vehicle's steering characteristics showing how over/understeer tends to occur depending on the steering angle when the vehicle speed increases.
  • the Ackermann yaw rate related to the characteristic speed can be expressed by Equation 1 below.
  • V x is the vehicle speed
  • wsa is the steering angle
  • L is the vehicle wheel base
  • V ch is the vehicle characteristic speed
  • the Ackerman yaw rate can be viewed as a yaw rate corresponding to the driver's desired steering intention, it can be used as a target yaw rate (TargetYaw) in terms of control.
  • the Ackerman yaw rate is used as the target yaw rate.
  • the characteristic speed of the vehicle may be obtained based on the above formula while steering left and right based on lateral acceleration of about 0.1 to 0.45 G (G: gravity acceleration).
  • G gravity acceleration
  • Over/under steer can generally be explained by a shift in the center of gravity due to a difference in slip angle between the front and rear wheels or a difference in load between the front and rear wheels.
  • the turning radius (R) is much larger than the wheel base (L) and there is almost no difference in steering angle between the inside and outside of the front wheel
  • the lateral/cornering force to maintain each desired turning at the front and rear wheels is given by the following equation 2 can be calculated.
  • F y is the lateral force
  • F y_f is the lateral force of the front wheels
  • F y_r is the lateral force of the rear wheels
  • M is the mass of the vehicle
  • V is the forward speed
  • R is the turning radius
  • ⁇ is the slip angle (slip angle)
  • C ⁇ is the cornering stiffness at a specific slip angle.
  • the lateral force on the side of the tire corresponds to a turning force based on a camber angle of 0 degrees, that is, a lateral force, and generally this value has a linear relationship with the slip angle as shown in the graph shown in FIG. 2 .
  • the slip angle of the front and rear wheels can be obtained as shown in Equation 3 by considering the lateral force of Equation 2 and the moment equilibrium at the center of the vehicle.
  • ⁇ f is the slip angle of the front wheel
  • ⁇ r is the slip angle of the rear wheel
  • W f is the weight load of the rear wheel
  • W r is the weight load of the rear wheel
  • C ⁇ is the cornering stiffness
  • g is the gravitational acceleration
  • R is the turning radius.
  • Equation 4 The relationship between the steering angle described in FIG. 1 and the tire slip angle described in Equation 3 can be expressed by Equation 4 below.
  • ⁇ is the steering angle
  • K is the under steer gradient (deg/s)
  • a y is the lateral acceleration (unit g)
  • L is the wheel base
  • R is the turning radius
  • understeer slope commonly known as the understeer slope (K)
  • the understeer slope (K) is related to the weight load of the front and rear wheels
  • Equation 4 it is again related to the slip angle of the front and rear wheels.
  • understeer means that the understeer gradient (K) is greater than 0, which means that the weight load on the front wheels is greater than that on the rear wheels, and the center of gravity is on the front wheels.
  • the slip angle of the front wheels is greater than the slip angle of the rear wheels. In this condition, as the vehicle speed increases at high speed, it means that the driver has to turn with a larger steering angle to avoid understeer.
  • the understeer gradient is less than 0, it means that the center of gravity is on the rear wheel side with the weight load on the rear wheel being larger than that on the front wheel, which also means that the slip angle of the rear wheel is greater than that of the front wheel.
  • the steering angle required by the driver is small. This means that in this condition, the driver must reduce the steering angle to avoid oversteer.
  • each steering mode is defined as an over/under steering mode when a driver steers according to over/under steer.
  • the over/under steering mode means steering that does not match the steering characteristics of the vehicle determined according to the aforementioned characteristic speed when the vehicle turns at the corresponding vehicle speed.
  • the steering angle is increased to cause excessive oversteer depending on the steering characteristics of the vehicle, or conversely, even though understeer should be avoided by making the steering angle larger, the steering angle is increased.
  • a steering mode that causes excessive understeer by maintaining or reducing it. Determination of such an over/under steering mode is applied as a main criterion for applying the limited target yaw control and crossing control according to an embodiment of the present invention.
  • Over-steering and under-steering may be determined by considering the steering angle, steering angular velocity, lateral acceleration, friction coefficient, the difference between the target yaw rate and the actual yaw rate, and the rate of change of the difference in the vehicle at the corresponding characteristic speed.
  • the yaw control method according to an embodiment of the present invention may be performed by an electronic control unit based on information such as yaw rate, steering angle, steering angular velocity, lateral acceleration, and vehicle speed.
  • Information used herein may be detected by various sensors installed in a vehicle and transmitted to an electronic control unit, and the electronic control unit may include a microprocessor, memory, and related hardware and software.
  • a microprocessor may be programmed to perform a yaw control method according to an embodiment of the present invention.
  • the driving road surface is a high-friction road surface while driving stability control that follows a normal road surface friction coefficient is performed (S11).
  • a general asphalt road may be determined as a high-friction road surface
  • a road surface covered with ice or snow may be determined as a low-friction road surface.
  • whether it is a high-friction road surface can be determined by comparing the magnitude of the vector sum of the lateral acceleration and the longitudinal acceleration of the vehicle with a threshold value. there is.
  • excessive/understeering reference values are calculated respectively (S12 and S13). This is because the reference values of the remaining conditions are different in determining over/under steering according to the degree of friction of the road surface.
  • the excessive/understeering reference value may include one or more reference values among a steering angle, a steering angular velocity, a lateral acceleration, a difference between a target yaw rate and an actual yaw rate, and a variation thereof.
  • a steering angular velocity of 50 degrees/s at a steering angle of 120 degrees can be a reference value, but a much lower reference value must be calculated because faster control is required than in the case of a low-friction road surface.
  • the condition that can be judged to cause excessive oversteer by the steering characteristics of the vehicle by increasing the steering angle even though the driver should avoid oversteer by reducing the steering angle is met, it is judged as oversteering.
  • the driver maintains or decreases the steering angle to avoid understeer by making the steering angle larger and the condition for determining that excessive understeer is satisfied, it can be determined as understeering.
  • the steering mode is determined based on the steering angle, the steering angular velocity, the difference between the target yaw rate and the actual yaw rate, and the variation thereof (S14 and S15). For example, it is determined whether it is an excessive steering mode (S14), and if it is not an excessive steering mode, it is determined whether it is an understeering mode (S15). Over-steering or under-steering may be determined based on driving information related to the yaw of the vehicle, for example, a steering angle, a steering angular velocity, a difference between a target yaw rate and an actual yaw rate, and a change amount thereof.
  • the aforementioned determination factors that is, the steering angle, steering angular velocity, the difference between the target yaw rate and the actual yaw rate, and their variations are excessive beyond the normal range, it can be determined as excessive steering mode, and if it is insufficient due to lower than the normal range, it can be determined as understeering mode.
  • the steering angle is greater than the preset oversteer threshold steering angle
  • the steering angular velocity is greater than the preset oversteer threshold steering angular velocity
  • the lateral acceleration is greater than the preset oversteer threshold lateral acceleration
  • the difference between the target yaw rate and the actual yaw rate If and the change amount thereof are greater than the preset threshold difference and threshold change amount of the excessive steering, it may be determined as the excessive steering mode.
  • the steering angle is smaller than the preset under-steering critical steering angle
  • the steering angular velocity is smaller than the preset under-steering critical steering angular velocity
  • the lateral acceleration is smaller than the preset under-steering critical lateral acceleration
  • the difference between the target yaw rate and the actual yaw rate and its If the amount of change is smaller than the preset under-steering threshold difference and the threshold change amount, the under-steering mode may be determined.
  • the over/under steering mode is determined, which can be calculated as a tuning factor after measuring and arranging the steering characteristics of the vehicle, such as the aforementioned characteristic speed.
  • step S14 If it is determined in step S14 that the excessive steering mode is in place, the excessive steering determination is turned on and the corresponding information is transmitted to the limited yaw rate control software and the crossing control software (S16). If it is determined that the steering is insufficient in step S15, the determination of insufficient steering is turned on and the corresponding information is transmitted to the proposed limit yaw rate control software and intersection control software (S17). Meanwhile, when it is determined that neither the over-steering mode nor the under-steering mode is found in steps S14 and S15, general control for steering stability is performed (S20).
  • the limited limit yaw rate control software and crossover control software are for performing the limited limit yaw rate control and crossover control to be described later, and the limited limit yaw rate control and crossover control will be described later.
  • the corresponding mode is maintained, and if it is small, the corresponding mode may be released. That is, in the case of the excessive steering mode, it is determined whether the difference between the road surface limit yaw rate and the actual yaw rate is greater than the minimum threshold for maintaining the excessive steering (S18), and if the determination result is positive, the excessive steering mode is maintained and if the determination result is negative The transient steering mode is released and general control is performed (S20).
  • insufficient steering mode it is determined whether the difference between the road surface limit yaw rate and the actual yaw rate is greater than the minimum threshold for maintaining insufficient steering (S19), and if the determination result is positive, the insufficient steering mode is maintained and the determination result is negative If the low-level steering mode is released, general control is performed (S20).
  • the yaw rate becomes larger than the reference target yaw rate at the time of judgment in case of over steering and much smaller in case of under steering.
  • this judgment is turned on, the limited yaw rate control and crossing control described later are operated.
  • EPS electric power steering system
  • rapid change in yaw rate due to over/under steering is controlled through electronic stability control.
  • Over-steering occurs when a yaw rate that exceeds the target yaw rate occurs, while under-steering occurs when a value far below the actual yaw rate occurs.
  • the under-steering mode is opposite to the over-steering mode and will be described below based on over-steering.
  • the difference in determining the understeering mode is that, unlike oversteering, the target limit yaw rate is determined in a proportionally larger direction, unlike oversteering, depending on the degree of insufficiency, because a much lower yaw rate has occurred as described above. am.
  • the present invention makes it possible to avoid this situation by controlling the change of the yaw moment due to excessive steering.
  • the target yaw rate in consideration of the driver's steering intention, for example, the Ackerman yaw rate in a limited form.
  • a limited yaw rate in a corresponding driving/turning situation may be determined in consideration of vehicle speed, road surface friction coefficient, lateral acceleration, and the like. This means that it is not based on the difference between the yaw rate reflecting the driver's steering intention and the actual yaw rate, but is controlled by the difference between the limited yaw rate and the actual yaw rate.
  • a situation in which the target yaw rate may exceed the limited target yaw rate may occur even if the actual yaw rate does not exceed the target yaw rate, so preemptively controlling situations that may deteriorate stability can take shape.
  • the limited target yaw rate is a function of vehicle speed, lateral acceleration, and friction coefficient and may be controlled according to Equation 5 below.
  • TGY Limited is the limited target yaw rate
  • a y is the lateral acceleration (unit g)
  • ⁇ is the coefficient of friction
  • V is the vehicle speed.
  • control is performed in the form of such a limited target yaw
  • a sudden yaw occurs as the vehicle rapidly leans
  • control is performed according to the difference between the limited target yaw and the actual yaw.
  • the difference value between the limited target yaw and the actual yaw is compared with a specific threshold criterion according to over/under steering of over/under steer described above. That is, over/under steer is determined depending on whether the difference between the limited target yaw and the actual yaw is greater or less than a corresponding threshold value.
  • oversteer it is possible to determine whether oversteering is performed and to determine whether the vehicle is oversteered, taking into consideration the reference threshold value determined accordingly and the aforementioned difference value.
  • the limited yaw rate may be determined based on the lateral acceleration, and the greater the lateral acceleration, the greater the limited yaw rate.
  • the shape of the limited yaw rate may be distorted compared to the driver's steering intention (steering angle and steering angular velocity) and the steering ability/tendency intended by the driver. Therefore, it is preferable that the shape of the yaw limited in the over-steering is controlled in such a way that the driver does not feel a sense of heterogeneity in consideration of the driver's steering intention and steering ability.
  • the tendency of the target yaw rate is followed so that the driver does not feel a sense of heterogeneity when turning, minimizing the shaking of the yaw due to the rapid inflection point of the yaw, and preemptively controllable like the existing limited target yaw rate. Since it is adjusted in size, both stability and steering aspects can be considered. That is, a limited target yaw rate as a ratio according to lateral acceleration and friction coefficient/vehicle speed is determined according to Equation 6 below, but a tendency of the target yaw rate is followed so as to have a smoother steering feel.
  • TGY Limited is the limited target yaw
  • a y is the lateral acceleration (unit g)
  • ⁇ is the coefficient of friction
  • V is the vehicle speed.
  • the ratio dynamically changes according to the movement of the vehicle speed, friction coefficient, and lateral acceleration, and the steering situation or steering intention.
  • the ratio may be composed of a tuning factor.
  • FIG. 5 it can be seen that the limited target yaw according to the embodiment of the present invention has a tendency more similar to the target yaw than the limited target yaw based on lateral acceleration, shown in the lower part of FIG.
  • front-wheel hydraulic pressure control may be performed according to a limited target yaw according to excessive steering determination.
  • the limited target yaw In relation to the operation of the electronic stability control (ESC), a sensitive operation is often an issue, and in this regard, the limited target yaw according to the present invention suggests a more flexible control method.
  • the ratio of the limited target yaw does not make a big difference from the Ackerman yaw, that is, the target yaw representing the driver's will.
  • the reason for this is that the more over/under steering in stages, the dynamically limited target yaw is created accordingly. To this end, it is important to judge over/under steering situations rather than neutral steering.
  • the target yaw is limited as a ratio tailored to the degree.
  • a target yaw dynamically limited to suit the excessive steering is created and controlled without causing a problem of sensitive operation.
  • 6 shows the concept of controlling the change in the ratio of the limiting yaw according to the embodiment of the present invention, and shows that the target yaw is dynamically limited according to various vehicle yaws.
  • the limited yaw rate according to the embodiment of the present invention is adjusted in proportion to the limit yaw rate, that is, in a state of having the same phase as the target yaw rate. If the steering angle after switching becomes much larger or much smaller than before switching, the limited target yaw in oversteering may be changed to be much smaller and much larger in understeering accordingly. As such, the limited target yaw can be dynamically adjusted according to each judgment and even in asymmetric left and right steering at the time of conversion.
  • the ratio and degree of dynamic adjustment are reduced to a more limited target yaw ratio when it is determined that stronger control is required during oversteering, and in the case of understeering, the ratio is increased to increase the change. can induce That is, a limited target yaw can be created while dynamically changing the ratio symmetrically/asymmetrically according to the steering situation.
  • the sudden change in yaw rate caused by excessive steering at high speed is primarily reduced by controlling the preemptive movement of the limited yaw at the rate described above, so that the stability of the vehicle can be improved.
  • control alone may have limitations depending on the degree of excessive steering, in the present invention, if it is determined that the remaining movement at the yaw rate primarily controlled according to the limited target yaw can still deteriorate the stability of the vehicle, the switching mechanism Through the secondary control, the yaw rate is controlled to be more stable.
  • Vehicle stability control through the ESC is performed through operation control of the solenoid valve, and there is a certain latency between application of a current signal for driving the solenoid valve and actual pressure generation. That is, in terms of control and command, even if an attempt is made to generate pressure for control in consideration of the above-mentioned dangerous situation after conversion, the actual pressure is generated later due to this delay, and the timing to control rapid yaw may be missed.
  • a transition mechanism is needed to account for this delay and ensure faster responsiveness to control oversteer situations that may occur after transition.
  • Figure 8 shows that the yaw is minimized in dotted line form by the proposed switching mechanism when it can cause problems after the remaining yaw switching motions that can still threaten the stability of the vehicle after control based on the previously described limited target yaw. It can be seen that the control through the brake pressure of the outer front wheel crosses before and after the transition section standard. Although the sudden change in yaw was minimized through the control of the front wheel previously, since the remaining yaw can cause problems after switching, the brake pressure of the next front wheel is generated in advance within this crossing section, and despite the delay problem mentioned above, these limitations are overcome. Show that you can overcome.
  • the crossing section is designed so that the overall size of the section increases as the switching operation occurs due to excessive steering.
  • over/under steering determination is presented as a basic condition, and the crossover control mechanism is operated only when the over/under steering determination is turned ON. This is to prevent sensitive operation and steering heterogeneity due to advanced pressure control according to unnecessary crossover control.
  • a transition period is defined and the crossing control mechanism is operated only when the transition period is met.
  • the start section of the crossing control section means such a code mismatch section.
  • an extended section is formed.
  • the extension section if the signs are identical but the change in yaw is still large and the lateral acceleration and change in lateral acceleration are large, the crossing control section is extended. This extended period is released when the next oversteer or understeer control is initiated.
  • the actuating structure in the designed crossing control section is made of a double structure.
  • the actual yaw and the sign of the yaw reflecting the driver's steering intention that is, whether the direction is different, whether oversteer (or understeer) occurs and is converted, and how the yaw change amount is considered.
  • the reference value of the yaw change amount that is, the threshold value is set differently from that in the second section, and the motor speed control and solenoid valve current for brake hydraulic control may also be set differently from those in the second section.
  • the current of the solenoid valve is for controlling the pressure of the brake oil
  • the motor is for controlling the rate of increase or decrease of the pressure of the brake oil.
  • a structure with a difference between both sections is possible.
  • a pressure gradient should be selected according to the situation with the purpose of providing pressure in advance to prevent a sudden change in yaw after switching without causing a problem of sensitive operation due to unnecessary pressure control.
  • the second section after the pressure is created, it is determined whether much faster pressure generation is necessary based on the yaw change and lateral acceleration, etc., and the control of the motor is changed to make the pressure rise slope different again.
  • This dual structure can control the solenoid valve current and motor speed the same or differently in the form of a dual structure according to the situation while minimizing the problem of sensitive operation in the switching operation, thereby enabling tuning tailored to various steering/turning situations. advantage is obtained. That is, the result of the first section is referred to in the second section, and through this, more flexible control is possible.
  • the difference between the actual yaw before switching and the target yaw based on the driver's will is large and the amount of change resulting from the difference is large, this information is transmitted to the switching mechanism. If the difference is large and the amount of change, which is the differential value, is large, the current of the solenoid valve can be controlled to maximize motor speed control in the first and second sections and to create pressure as quickly as possible. Conversely, if the difference before switching is small or the amount of change for the difference is not large, more flexible switching control can be achieved by adjusting the motor and adjusting the valve pressure as necessary so as not to cause side effects by excessive control. .
  • control elements for over/under steer control for example, solenoid valves, motors, and other actuators for controlling braking of each wheel are controlled to cross each other, and at this time, by dividing into a plurality of sections, Cross control is achieved.
  • the current of the solenoid valve and the speed setting value of the motor in the first section in the crossing section may be made by Equation 7 below.
  • Tcv Current_1st is the solenoid valve current in the first section
  • Tcv Init_cross is the initial solenoid valve current in the crossing section
  • M Speed_1st is the motor speed set value in the first section
  • M Init_cross is the initial motor speed in the crossing section.
  • Yaw_err is the difference between the current target yaw and actual yaw
  • YawErr_dot is the change (differential value) of Yaw_err
  • Yaw_err_b is the difference between the target yaw and actual yaw before switching
  • YawErr_dot_b is the change (differential value) of Yaw_err_b
  • a y is the lateral acceleration (unit g)
  • ⁇ is the coefficient of friction
  • V is the vehicle speed.
  • Equation 8 setting of the valves and motors in the second section in the crossing section may be performed by Equation 8 below.
  • Tcv Current_2nd is the solenoid valve current in the second section
  • Tcv Init_cross_2nd is the initial solenoid valve current in the second section
  • Tcv Current_1st is the solenoid valve current in the first section
  • M Speed_2nd is the motor in the second section.
  • M Init_cross_2nd is the initial motor speed setting value of the second section
  • M Speed_1st is the motor speed setting value in the first section
  • Yaw_err is the difference between the current target yaw and actual yaw
  • YawErr_dot is the amount of change in Yaw_err (differential value)
  • Yaw_err_b is the difference between the target yaw and actual yaw before switching
  • YawErr_dot_b is the amount of change in Yaw_err_b (differential value)
  • a y is the lateral acceleration (unit g)
  • ⁇ is the friction coefficient
  • V is the vehicle speed am.
  • the set value of the solenoid valve and the motor in the dual structure is determined by considering the difference between the actual yaw and the target yaw before and after switching and the amount of change in the difference. It is also determined by considering the current difference and the amount of change therefor.
  • the set values of the solenoid valve and motor calculated in the first section are additionally considered.
  • a three-step crossover structure consisting of three steps may be applied. In this case, the intermediate step may adopt a proportional function considering the set values of the front and back.
  • the speed/front wheel control values for the motor and the solenoid valve can be the same or different for each section.
  • Such a flexible structure becomes a flexible structure for fish tailing due to shaking of the yaw due to excessive control or improvement of steering feeling and relief of heterogeneity due to insufficient control.
  • FIG. 11 is a flow chart of a switching mechanism for controlling cross-sections of a dual structure type according to an embodiment of the present invention
  • FIG. 12 shows section-by-section control based on step-by-step yaw information in a dual structure according to an embodiment of the present invention.
  • graph that shows According to an embodiment of the present invention, a structure capable of differentially controlling the intersection section in a two-step (or three-step) form while considering the difference between the target yaw (or limited target yaw) and the actual yaw before conversion and the value after conversion A flexible response is possible.
  • a form of proportional derivative control can be used in the intersection control section of the dual structure.
  • control of the second interval is performed by transferring stability control information of the first interval, for example, yaw rate information and proportional derivative information, etc. to the second interval.
  • the proportional derivative value may be determined considering vehicle speed and road surface information as well as yaw information.
  • an understeer situation after conversion or a situation in which oversteer and understeer change before and after conversion may be considered.
  • a different determination from the previously described steering mode determination must be made. For example, if the vehicle turns in the excessive steering mode before switching and then switches to a small steering angle very late at the time of switching, the understeering mode may be determined again. That is, for example, when the difference between the target yaw and the actual yaw and the change amount appear as negative values, that is, a value of the opposite sign because the conversion is too late, and the understeering determination criterion is exceeded, an understeering determination is made. This change in judgment may occur in the crossing control period.
  • control for the outer front wheel or the inside rear wheel of the vehicle can be prepared in advance for under/oversteer, so that the situation after conversion can be more flexibly dealt with.
  • prepared pressure exists on the inside rear wheel or the outside front wheel, but if over/under steer does not occur in the situation after that, the prepared inside and outside pressure is discharged. This is in consideration of sensitive motions, and most of the sensitive motions are determined and processed in the first conversion decision.
  • oversteer, transition, and oversteer the left and right pressure and intersection of the front wheels are controlled, and as shown in the example of FIG. You can control it.
  • crossover control according to an embodiment of the present invention can provide a variety of more flexible over/understeer control structures.
  • FIG. 14 is a flowchart of limited target yaw setting and crossing control according to over/under steering mode determination according to an embodiment of the present invention.
  • over/under steering determination is made (S31), and it is determined whether or not a condition for maintaining the over/under steering mode is satisfied (S32).
  • S32 a condition for maintaining the over/under steering mode is satisfied
  • S33 general over/under steer control is performed (S33).
  • a limited target yaw is set (S34). Then, it is determined whether crossover control is necessary (S35). Whether or not crossing control is required may be made as described above. If it is determined that crossover control is not required, it is determined again whether the condition for maintaining the excessive/understeering mode is satisfied (S36). If it is determined that the condition for maintaining the over/under steering mode is not satisfied in step S36, general over/under steer control is performed (S33), and when it is determined that the condition for maintaining the over/under steering mode is satisfied in step S, Over/under steer control is performed according to the limited target yaw (S37).
  • a crossover control section is set (S38).
  • the crossing control section may be divided into two sections, that is, a first section and a second section, and a control value in each section may be set.
  • crossover control is performed in the first section through control of actuators, motors, solenoid valves, etc. (S39), and then crossover control is performed in the second section (S40).
  • the previously determined value may be changed by referring to the processing result of the first section in the second section, if necessary.
  • FIG. 15 is a graph showing the result of yaw control after sudden changeover steering by the control method according to an embodiment of the present invention. As shown in FIG. 15, it is possible to confirm the improvement in control performance by the limited target yaw and switching mechanism of the present invention through a stable control situation of yaw after rapid steering in an actual vehicle. As shown in FIG. 15, when there is a sharp turn steering, a road surface limit yaw suitable for the situation is made, and if excessive yaw due to sudden steering after the change is predicted through a step-by-step structure at point "A", the pressure to reduce it is applied at point "A" It is output while crossing each other with the previous pressure.
  • FIG. 16 is a graph showing the result of yaw control through a sinusoidal road limit yaw and a switching mechanism according to an embodiment of the present invention.
  • FIG. 16 shows a graph showing actual vehicle performance in a situation when turning in the opposite direction with a quick change, and shows that stable yaw control is achieved.
  • the present invention proposes a step-by-step control method in an abrupt switching operation along with a sine wave type limit yaw according to the road surface.
  • a very flexible structure is proposed even in terms of sensitive operation of the ESC, which is a so-called problem, and the above switching mechanism operates according to the driving/turning situation of the vehicle, enabling deep crossing conversion as well as shallower crossing. do.
  • the cross pressure structure does not operate in situations where control is not required, a more flexible structure is proposed for sensitive operation issues.
  • the present invention relates to a method for controlling the yaw of a vehicle, and has industrial applicability since it can be applied to driving control of a vehicle.

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Abstract

This method for controlling the yaw of a vehicle comprises the steps of: setting an over-steering reference value and an under-steering reference value for a high-friction road surface and an over-steering reference value and an under-steering reference value for a low-friction road surface; determining whether over-steering or under-steering is detected, on the basis of driving information related to the yaw of a vehicle, the over-steering reference values, and the under-steering reference values; and when it is determined that the over-steering or the under-steering is detected, controlling a yaw rate according to a limited yaw rate whose ratio is adjusted while maintaining the same phase as that of a pre-determined limit yaw rate.

Description

차량의 요 제어 방법Vehicle yaw control method
본 발명은 차량의 전자 안정성 제어에 관한 것이며, 보다 구체적으로 오버 스티어 및 언더 스티어를 제어하는 방법에 관한 것이다.The present invention relates to electronic stability control of a vehicle, and more particularly to a method for controlling oversteer and understeer.
차량의 전자식 안정성 제어(ESC, Electronic Stability Control)를 통해 자동차의 주행 안정성을 향상시키며, 그 한 예로 과도조향에 의한 오버 스티어에 대응하는 제어가 이루어진다.Driving stability of a vehicle is improved through electronic stability control (ESC) of the vehicle, and as an example, control corresponding to oversteer caused by excessive steering is performed.
소프트웨어적인 한계, 차량 조건 또는 주행 조건 등에 의해 과도 조향 시의 차량의 요 레이트(yaw rate)의 불안정성을 저감하고 제어하기 위한 여러 가지 방법들이 제시되었다. 그러나 전환 구간의 이중 구조나 조향성을 반영하여 상황에 맞게 조정되어 제한되는 요 제어 방법은 많지 않다.Various methods for reducing and controlling the instability of the yaw rate of a vehicle during excessive steering due to software limitations, vehicle conditions, or driving conditions have been proposed. However, there are not many yaw control methods that are adjusted and limited according to the situation by reflecting the dual structure or steering of the transition section.
또한 조향성을 고려하며 제한되는 요 레이트 제어 기반의 구조와 이중 전환 구조에서의 교차 압력 구조를 통해 차량의 안정성을 유지하기 위한 방법이 필요하다.In addition, a method for maintaining the stability of the vehicle through a structure based on yaw rate control that is limited while considering steering and a cross-pressure structure in a double switching structure is required.
나아가 속도 저감을 통한 요 레이트의 안정화 방법도 중요하나 속도 저감 방법을 사용할 수 없는 경우이거나 속도를 줄이기 힘든 상황에서 속도 조감을 통한 방식보다 조향감이나 주행 성능 측면에서 상대적으로 더 좋은 결과를 가져올 수 있는 효과적인 요 제어 방법이 요구된다.Furthermore, the method of stabilizing the yaw rate through speed reduction is also important, but when the speed reduction method cannot be used or in a situation where it is difficult to reduce speed, it can bring relatively better results in terms of steering feel or driving performance than the method through speed control. An effective yaw control method is required.
<선행기술문헌><Prior art literature>
- 대한민국 등록특허공보 제10-1609889호 (공고일: 2016.04.20.)- Republic of Korea Patent Registration No. 10-1609889 (Announcement date: 2016.04.20.)
- 대한민국 공개특허공보 제10-2006-0014468호 (공개일: 2006.02.16.)- Republic of Korea Patent Publication No. 10-2006-0014468 (published date: 2006.02.16.)
본 발명이 해결하고자 하는 과제는 차량의 안정성을 유지하면서 운전자의 조향 의지를 추종하여 반영할 수 있는 요 제어 방법을 제공하는 것이다.An object of the present invention is to provide a yaw control method capable of following and reflecting a driver's steering intention while maintaining vehicle stability.
본 발명의 실시예에 따른 차량의 요 제어 방법은 고마찰 노면에 대한 과도 조향 기준값 및 부족 조향 기준값과 저마찰 노면에 대한 과도 조향 기준값과 부족 조향 기준값을 각각 설정하는 단계, 차량의 요와 관련된 주행 정보와 상기 과도 조향 기준값 및 상기 부족 조향 기준값을 기초로 과도 조향 또는 부족 조향 여부를 판단하는 단계, 그리고 상기 과도 조향 또는 상기 부족 조향인 것으로 판단되는 경우 미리 결정된 한계 요 레이트와 동일한 위상을 유지하면서 비율이 조정된 제한된 한계 요 레이트에 따라 요 레이트를 제어하는 단계를 포함한다.A method for controlling yaw of a vehicle according to an embodiment of the present invention includes the steps of setting oversteering reference values and understeering reference values for a high-friction road surface and oversteering reference values and understeering reference values for a low-friction road surface, respectively; Determining whether over-steering or under-steering is based on the information, the over-steering reference value, and the under-steering reference value, and if it is determined that the over-steering or under-steering ratio while maintaining the same phase as the predetermined limit yaw rate and controlling the yaw rate according to the adjusted limited threshold yaw rate.
상기 과도 조향 기준값과 상기 부족 조향 기준값은 조향각, 조향각속도, 횡가속도, 목표 요 레이트와 실제 요 레이트의 차이 및 이의 변화량 중 하나 이상의 기준값을 각각 포함할 수 있다.The excessive steering reference value and the understeering reference value may each include one or more reference values of a steering angle, a steering angular velocity, a lateral acceleration, a difference between a target yaw rate and an actual yaw rate, and a variation thereof.
본 발명의 다른 실시예에 따른 차량의 요 제어 방법은 상기 과도 조향 또는 상기 부족 조향인 것으로 판단되는 경우 오버/언더 스티어 제어를 위해 각 휠의 브레이킹의 제어를 위한 복수의 제어 요소를 서로 교차하도록 제어하는 교차 제어를 수행하는 단계를 더 포함할 수 있다. 상기 교차 제어는 복수의 교차 구간으로 구분되어 이루어질 수 있고, 상기 교차 구간의 안정성 제어를 위한 정보가 다음 교차 구간으로 전달되어 사용되도록 구성될 수 있다.A method for controlling yaw of a vehicle according to another embodiment of the present invention controls a plurality of control elements for controlling braking of each wheel to cross each other for over/under steer control when it is determined that the oversteering or understeering is performed. It may further include the step of performing crossover control. The crossing control may be performed by dividing into a plurality of crossing sections, and the information for stability control of the crossing section may be transmitted to the next crossing section and used.
상기 교차 구간은 과도한 조향에 따른 전환 동작일수록 전체 크기가 커지도록 설계될 수 있다.The crossing section may be designed to increase in overall size as a switching operation occurs due to excessive steering.
상기 교차 구간의 안정성 제어를 위한 정보는 요 레이트 정보와 비례미분 정보를 포함할 수 있다.The information for stability control of the crossing section may include yaw rate information and proportional derivative information.
본 발명의 다른 실시예에 따른 차량의 요 제어 방법은 고마찰 노면에 대한 과도 조향 기준값 및 부족 조향 기준값과 저마찰 노면에 대한 과도 조향 기준값과 부족 조향 기준값을 각각 설정하는 단계, 차량의 요와 관련된 주행 정보와 상기 과도 조향 기준값 및 상기 부족 조향 기준값을 기초로 과도 조향 또는 부족 조향 여부를 판단하는 단계, 상기 과도 조향 또는 상기 부족 조향인 것으로 판단되는 경우 미리 결정된 한계 요 레이트를 조정하여 얻어지는 제한된 한계 요 레이트에 따라 요 레이트를 제어하는 단계, 그리고 상기 과도 조향 또는 상기 부족 조향인 것으로 판단되는 경우 오버/언더 스티어 제어를 위해 각 휠의 브레이킹의 제어를 위한 복수의 제어 요소를 서로 교차하도록 제어하는 교차 제어를 수행하는 단계를 포함한다. 상기 교차 제어는 복수의 교차 구간으로 구분되어 이루어지고, 상기 교차 구간의 안정성 제어를 위한 정보가 다음 교차 구간으로 전달되어 사용되도록 구성된다.A method for controlling yaw of a vehicle according to another embodiment of the present invention includes the steps of setting oversteering reference values and understeering reference values for a high-friction road surface and oversteering reference values and understeering reference values for a low-friction road surface, respectively, related to the yaw of the vehicle. Determining whether over-steering or under-steering is based on driving information, the over-steering reference value, and the under-steering reference value, and a limited limit yaw rate obtained by adjusting a predetermined limit yaw rate when it is determined that the over-steering or under-steering is the case. Controlling the yaw rate according to the rate, and crossing control for controlling a plurality of control elements for controlling the braking of each wheel to cross each other for over/under steer control when it is determined that the oversteer or understeer is the case. It includes the steps of performing The crossing control is performed by dividing into a plurality of crossing sections, and the information for stability control of the crossing section is transferred to the next crossing section and used.
본 발명에 의하면, 차량의 안정성을 유지하면서 운전자의 조향 의지를 추종하여 반영할 수 있는 요 제어가 이루어질 수 있다.According to the present invention, yaw control that can follow and reflect the driver's steering intention while maintaining vehicle stability can be achieved.
도 1은 차량의 조향각과 차속에 따른 조향 특성을 보여주는 그래프를 도시한다.1 is a graph showing steering characteristics according to a steering angle and vehicle speed of a vehicle.
도 2는 차량의 슬립 각도와 횡력 사이의 관계를 보여주는 그래프를 도시한다.2 shows a graph showing the relationship between the vehicle's slip angle and the lateral force.
도 3은 본 발명의 실시예에 따른 차량의 요 제어 방법의 과도/부족 조향 판단 과정의 순서도를 도시한다.3 is a flowchart of a process for determining over/under steering of a method for controlling yaw of a vehicle according to an embodiment of the present invention.
도 4는 과도/부족 조향 판단의 예를 보여주는 그래프를 도시한다.4 shows a graph showing an example of over/under steering determination.
도 5는 본 발명의 실시예에 따른 제한된 목표 요 레이트를 통한 오버 스티어 제어를 보여주는 그래프를 도시한다.5 is a graph showing oversteer control with a limited target yaw rate according to an embodiment of the present invention.
도 6은 본 발명의 실시예에 따른 제한된 목표 요 레이트의 비율 변화 제어를 보여주는 그래프를 도시한다.6 is a graph showing control of a rate change of a limited target yaw rate according to an embodiment of the present invention.
도 7은 본 발명의 실시예에 따른 과도/부족 조향 판단에 따른 동적인 제한된 목표 요의 동적 변화의 예를 보여주는 그래프를 도시한다.7 is a graph showing an example of a dynamic change of a dynamic limited target yaw according to over/under steering determination according to an embodiment of the present invention.
도 8은 본 발명의 실시예에 따른 전환 메커니즘에 따른 요의 최소화 제어를 보여주는 그래프를 도시한다.8 is a graph showing a control for minimizing urine according to a switching mechanism according to an embodiment of the present invention.
도 9는 본 발명의 실시예에 따른 교차 제어 구간의 가능한 형태의 예를 보여주는 그래프를 도시한다.9 shows a graph showing an example of a possible form of a crossing control section according to an embodiment of the present invention.
도 10은 본 발명의 실시예에 따른 이중 구조 형태의 교차 구간에서의 솔레노이드 밸브와 모터의 설정값의 유연한 제어 형태를 보여주는 그래프를 도시한다.10 is a graph showing a flexible control form of set values of a solenoid valve and a motor in an intersection section of a dual structure type according to an embodiment of the present invention.
도 11은 본 발명의 실시예에 따른 이중 구조 형태의 교차 구간으로 제어하는 전환 메커니즘의 순서도를 도시한다.11 is a flow chart of a switching mechanism for controlling a cross section of a dual structure type according to an embodiment of the present invention.
도 12는 본 발명의 실시예에 따른 이중 구조에서 단계별 요 레이트 정보에 기초하는 구간별 제어를 보여주는 그래프를 도시한다.12 is a graph showing control for each section based on yaw rate information for each step in a dual structure according to an embodiment of the present invention.
도 13은 본 발명의 실시예에 따른 전환 전후의 상황에 따른 교차 구간에서의 외측/외측 전후륜 압력의 형태를 보여주는 그래프를 도시한다.13 is a graph showing the shape of the lateral/lateral front and rear wheel pressures in an intersection section according to situations before and after switching according to an embodiment of the present invention.
도 14는 본 발명의 실시예에 따른 차량의 요 제어 방법의 제한된 목표 요 설정 및 교차 제어의 과정을 보여주는 순서도를 도시한다.14 is a flowchart showing a process of setting a limited target yaw and controlling intersection in a method for controlling yaw of a vehicle according to an embodiment of the present invention.
도 15는 본 발명의 실시예에 따른 제어 방법에 의해 급격한 전환 조향 후 요 레이트 제어의 결과를 보여주는 그래프를 도시한다.15 is a graph showing a result of yaw rate control after sudden changeover steering by a control method according to an embodiment of the present invention.
도 16은 본 발명의 실시예에 따른 정현파 형태의 노면 한계 요와 전환 메커니즘을 통한 요 레이트 제어의 결과를 보여주는 그래프를 도시한다.16 is a graph showing a result of yaw rate control through a sinusoidal road limit yaw and a switching mechanism according to an embodiment of the present invention.
아래에서 첨부된 도면을 참조하여 본 발명의 실시예에 대해 본 발명이 속하는 기술분야에서 통상의 지식을 가지는 자가 용이하게 실시할 수 있도록 상세히 설명한다. 그러나 본 발명은 여러 가지 상이한 형태로 구현될 수 있으며 설명된 실시예에 한정되지 않는다.Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. However, the present invention may be embodied in many different forms and is not limited to the described embodiments.
차량의 전자식 안정성 제어(ESC)는 차량의 안정성(stability)을 확보하는 것을 주요 목적으로 하며 또한 안정성에 우선을 두면서도 조향성이나 주행성능도 고려하여 이루어진다. 예를 들어, 차량의 고속 선회 및 주행에서 일반적으로 차량의 안정성이 저하될 경우, 운전자가 요구하거나 원하는 선회 반경보다 훨씬 작은 선회 반경으로 차량이 스핀아웃(spin-out)하는 현상이 발생할 수 있다. 반면, 원하는 선회 반경 및 코스를 위한 선회 속도 대비 차량의 선회 속도가 훨씬 작을 경우 차량이 드리프트 되면서 밀려나는 플로우(plow) 현상이 발생할 수 있다. 전자의 경우와 후자의 경우를 오버 스티어(over steer)와 언더 스티어(under steer)라고 할 수 있으며, 과도하거나 부족한 선회 속도를 차량의 요 모멘트(yaw moment)로 이해할 수 있다.The main purpose of electronic stability control (ESC) of a vehicle is to secure vehicle stability, and while giving priority to stability, steering and driving performance are also considered. For example, when vehicle stability is generally deteriorated during high-speed turning and driving of a vehicle, a phenomenon in which the vehicle spins out may occur with a turning radius much smaller than a driver's requested or desired turning radius. On the other hand, when the turning speed of the vehicle is much smaller than the turning speed for the desired turning radius and course, a plow phenomenon in which the vehicle is pushed while drifting may occur. The former case and the latter case can be referred to as oversteer and understeer, and excessive or insufficient turning speed can be understood as the yaw moment of the vehicle.
차량의 조향 특성은 도 1과 같이 조향각(tire angle)과 차속을 두 축으로 하는 그래프로 나타낼 수 있다. 특성 속도(characteristic speed)(Vch)는 선회 시 이를 유지하기 위한 요구 조향각인 애커만 각도의 2배에 해당하는 차속을 의미하고, 임계 속도(critical speed)는 오버 스티어 상황에서의 차량의 거동이 불안정해지는 속도를 의미한다. 차량의 특성 속도는 해당 차량에서 차속 증가 시 조향각에 따라 오버/언더 스티어가 어떻게 어떠한 경향으로 일어나는지를 보여주는 차량의 조향 특성에 해당한다. 특성 속도에 관련된 애커만 요 레이트(Ackermann yaw rate)는 다음 수학식 1로 나타낼 수 있다.As shown in FIG. 1 , vehicle steering characteristics may be represented by a graph having two axes, a tire angle and a vehicle speed. The characteristic speed (V ch ) means the vehicle speed corresponding to twice the Ackerman angle, which is the required steering angle to maintain it when turning, and the critical speed is the vehicle's behavior in an oversteer situation. Indicates the rate of instability. The vehicle's characteristic speed corresponds to the vehicle's steering characteristics showing how over/understeer tends to occur depending on the steering angle when the vehicle speed increases. The Ackermann yaw rate related to the characteristic speed can be expressed by Equation 1 below.
Figure PCTKR2023002779-appb-img-000001
Figure PCTKR2023002779-appb-img-000001
여기서, yrTgAkm는 애커만 요 레이트이고, Vx는 차량 속도이고, wsa는 조향각이고, L은 차량 휠 베이스이고, Vch는 차량 특성 속도이다.where yrTgAkm is the Ackerman yaw rate, V x is the vehicle speed, wsa is the steering angle, L is the vehicle wheel base, and V ch is the vehicle characteristic speed.
애커만 요 레이트는 운전자가 원하는 조향 의지에 해당하는 요 레이트로 볼 수 있기 때문에 제어 측면에서 목표 요 레이트(TargetYaw)로 사용될 수 있다. 본 발명에서는 애커만 요 레이트를 목표 요 레이트로 사용한다.Since the Ackerman yaw rate can be viewed as a yaw rate corresponding to the driver's desired steering intention, it can be used as a target yaw rate (TargetYaw) in terms of control. In the present invention, the Ackerman yaw rate is used as the target yaw rate.
해당 차량의 특성 속도는 0.1 내지 0.45 G (G: 중력 가속도) 정도의 횡가속도를 기준으로 좌우 조향을 하면서 위 수식에 기초하여 구해질 수 있다. 일반적으로 이러한 특성 속도는 해당 차량의 고유 조향 특성에 해당하기 때문에, 차량의 조향과 관련된 주요 요 모멘트를 제어하고자 할 때 중요한 기준으로 활용된다.The characteristic speed of the vehicle may be obtained based on the above formula while steering left and right based on lateral acceleration of about 0.1 to 0.45 G (G: gravity acceleration). In general, since these characteristic speeds correspond to the unique steering characteristics of a corresponding vehicle, they are used as an important criterion when trying to control a major yaw moment related to steering of a vehicle.
오버/언더 스티어는 일반적으로 전후륜의 슬립 앵글(slip angle)의 차이나 전후륜의 하중 차이에 따른 무게중심의 이동 등으로 설명될 수 있다. 선회 반경(R)이 휠 베이스(L)보다 훨씬 크고 전륜의 내외측의 조향각 차이가 거의 없다고 가정하면 전후륜에서의 각각의 원하는 선회를 유지하기 위한 횡력(lateral/cornering force)은 다음의 수학식 2에 따라 산출될 수 있다.Over/under steer can generally be explained by a shift in the center of gravity due to a difference in slip angle between the front and rear wheels or a difference in load between the front and rear wheels. Assuming that the turning radius (R) is much larger than the wheel base (L) and there is almost no difference in steering angle between the inside and outside of the front wheel, the lateral/cornering force to maintain each desired turning at the front and rear wheels is given by the following equation 2 can be calculated.
Figure PCTKR2023002779-appb-img-000002
Figure PCTKR2023002779-appb-img-000002
여기서, Fy는 횡력이고, Fy_f는 전륜의 횡력이고, Fy_r은 후륜의 횡력이고, M은 차량의 질량이고, V는 전방향 속도이고, R은 선회 반경이고, α는 슬립 각도(slip angle)이고, Cα는 특정 슬립 각도에서의 코너링 강성(cornering stiffness)이다.Here, F y is the lateral force, F y_f is the lateral force of the front wheels, F y_r is the lateral force of the rear wheels, M is the mass of the vehicle, V is the forward speed, R is the turning radius, and α is the slip angle (slip angle), and C α is the cornering stiffness at a specific slip angle.
차량이 고속으로 선회할 때 타이어의 횡력이 발생하고, 횡력은 노면 상태(마찰계수), 차속에 영향을 받는다. 횡력은 타이어가 노면과 접촉한 면의 비틀림에 따라 발생하며 이로 인해 타이어와 차량 방향 사이의 차이가 발생한다. 이를 통해 각 휠에 슬립각이 자연스럽게 나타난다. 타이어의 측면에서의 횡력은 캠버각 0도 기준 선회력, 즉 횡력에 해당하며, 일반적으로 이 값은 슬립 각도와 도 2에 나타난 그래프와 같은 선형적인 관계를 가진다.When a vehicle turns at high speed, tire lateral force is generated, and the lateral force is affected by road surface conditions (friction coefficient) and vehicle speed. Lateral force is caused by twisting of the surface in contact with the road surface, which causes a difference between the tire and the direction of the vehicle. Through this, the slip angle appears naturally on each wheel. The lateral force on the side of the tire corresponds to a turning force based on a camber angle of 0 degrees, that is, a lateral force, and generally this value has a linear relationship with the slip angle as shown in the graph shown in FIG. 2 .
수학식 2의 횡력을 차량 중심에서의 모멘트 평형을 고려하여 전후륜의 슬립 각도를 다음의 수학식 3과 같이 구할 수 있다.The slip angle of the front and rear wheels can be obtained as shown in Equation 3 by considering the lateral force of Equation 2 and the moment equilibrium at the center of the vehicle.
Figure PCTKR2023002779-appb-img-000003
Figure PCTKR2023002779-appb-img-000003
여기서, αf는 전륜의 슬립 각도이고, αr는 후륜의 슬립 각도이고, Wf는 후륜의 무게 하중이고, Wr는 후륜의 무게 하중이고, Cα는 코너링 강성이고, g는 중력 가속도이고, R은 선회 반경이다.where α f is the slip angle of the front wheel, α r is the slip angle of the rear wheel, W f is the weight load of the rear wheel, W r is the weight load of the rear wheel, C α is the cornering stiffness, g is the gravitational acceleration, , R is the turning radius.
도 1에 기술된 조향각과 수학식 3에 기술된 타이어의 슬립 각도의 관계는 다음 수학식 4에 의해 표현될 수 있다.The relationship between the steering angle described in FIG. 1 and the tire slip angle described in Equation 3 can be expressed by Equation 4 below.
Figure PCTKR2023002779-appb-img-000004
Figure PCTKR2023002779-appb-img-000004
여기서, δ는 조향각이고, K는 부족 조향 구배(under steer gradient, deg/s)이고, ay는 횡 가속도(단위 g)이고, L은 휠 베이스이고, R은 선회 반경이다.where δ is the steering angle, K is the under steer gradient (deg/s), a y is the lateral acceleration (unit g), L is the wheel base, and R is the turning radius.
일반적으로 부족 조향 구배(K)로 알려진 언더 스티어 기울기를 보면, 전후륜의 무게 하중과 관련된 것을 알 수 있고, 수학식 4에서 알 수 있는 바와 같이 다시 이것은 전후륜의 슬립 각도와 관련된 것을 알 수 있다. 즉 언더 스티어는 부족 조향 구배(K)가 0보다 큰 것을 의미하는데 이는 전륜의 무게 하중이 후륜보다 큰 상태로 무게 중심이 전륜 쪽에 있음을 의미한다. 이는 전륜의 슬립 각도가 후륜의 슬립 각도보다 크다는 것을 의미하는 것이기도 하다. 이러한 상태에서는 차속이 고속으로 올라갈수록 운전자가 언더 스티어를 회피하기 위해서 더 큰 조향각으로 선회를 해야 한다는 것을 의미한다. 반면, 부족 조향 구배가 0보다 작다는 것은 후륜의 무게 하중이 전륜보다 큰 상태로 무게 중심이 후륜 쪽에 있음을 나타내고 또한 이는 후륜의 슬립 각도가 전륜보다 크다는 것을 의미한다. 이 경우 운전자에게 요구되는 조향각이 작다. 즉 이러한 상태에서는 운전자가 오버 스티어를 회피하기 위해 조향각을 줄여야 한다는 것을 의미한다.Looking at the understeer slope, commonly known as the understeer slope (K), it can be seen that it is related to the weight load of the front and rear wheels, and as can be seen from Equation 4, it is again related to the slip angle of the front and rear wheels. . That is, understeer means that the understeer gradient (K) is greater than 0, which means that the weight load on the front wheels is greater than that on the rear wheels, and the center of gravity is on the front wheels. This also means that the slip angle of the front wheels is greater than the slip angle of the rear wheels. In this condition, as the vehicle speed increases at high speed, it means that the driver has to turn with a larger steering angle to avoid understeer. On the other hand, if the understeer gradient is less than 0, it means that the center of gravity is on the rear wheel side with the weight load on the rear wheel being larger than that on the front wheel, which also means that the slip angle of the rear wheel is greater than that of the front wheel. In this case, the steering angle required by the driver is small. This means that in this condition, the driver must reduce the steering angle to avoid oversteer.
오버/언더 스티어를 회피하기 위해 조향각을 증가시키거나 줄이지 않으면 앞에서 언급한 것처럼 슬립 각도 또는 무게이동에 따른 하중 이동으로 인해 요 레이트의 급격한 변화가 유발될 수 있다. 저마찰로 또는 고마찰로 노면 조건 외에도 현재 주행 상태에서 특정 조향 모드로 운전자가 조작 시에 이러한 요 레이트의 변화는 더욱 급격해져 차량의 안정성이 크게 저해된다. 본 발명의 실시예에서는 이러한 점을 고려하여 조향 모드를 오버/언더 스티어에 맞추어 운전자가 조향 시에 해당 모드 각각을 과도/부족 조향 모드로 정의한다. 과도/부족 조향 모드는 해당 차량이 해당 차속에서 선회 시 앞에서 설명한 특성 속도에 따라 결정된 차량의 조향 특성에 맞지 않는 조향을 의미한다. 즉 과도/부족 조향 모드는 조향각을 작게 하여 오버 스티어를 회피해야 함에도 조향각을 크게 하여 해당 차량의 조향 특성에 의해 오히려 과도한 오버 스티어를 유발하게 하거나 반대로 조향각을 더 크게 하여 언더 스티어를 회피해야 함에도 조향각을 유지하거나 작게 하여 과도한 언더 스티어를 유발하는 조향 모드를 의미한다. 이러한 과도/부족 조향 모드의 판단이 본 발명의 실시예에 따른 제한된 목표 요 제어 및 교차 제어의 적용의 주요 기준으로 적용된다. 과도 조향 및 부족 조향은 해당 특성 속도의 차량에서 조향각, 조향각속도, 횡가속도, 마찰계수, 목표 요 레이트와 실제 요 레이트의 차이 그리고 이 차이의 변화율을 고려하여 판단될 수 있다.If the steering angle is not increased or decreased to avoid over/under steer, as mentioned above, a sudden change in yaw rate may be induced due to the slip angle or the load movement according to the weight movement. In addition to the low-friction road or high-friction road surface conditions, when the driver operates in a specific steering mode in the current driving state, the change in the yaw rate becomes more rapid, greatly deteriorating the stability of the vehicle. In the embodiment of the present invention, in consideration of this point, each steering mode is defined as an over/under steering mode when a driver steers according to over/under steer. The over/under steering mode means steering that does not match the steering characteristics of the vehicle determined according to the aforementioned characteristic speed when the vehicle turns at the corresponding vehicle speed. In other words, in the over/under steering mode, although oversteer should be avoided by making the steering angle smaller, the steering angle is increased to cause excessive oversteer depending on the steering characteristics of the vehicle, or conversely, even though understeer should be avoided by making the steering angle larger, the steering angle is increased. A steering mode that causes excessive understeer by maintaining or reducing it. Determination of such an over/under steering mode is applied as a main criterion for applying the limited target yaw control and crossing control according to an embodiment of the present invention. Over-steering and under-steering may be determined by considering the steering angle, steering angular velocity, lateral acceleration, friction coefficient, the difference between the target yaw rate and the actual yaw rate, and the rate of change of the difference in the vehicle at the corresponding characteristic speed.
본 발명의 실시예에 따른 요 제어 방법은 요 레이트, 조향각, 조향각속도, 횡가속도, 차속 등의 정보를 기초로 전자 제어 유닛(electronic control unit)에 의해 수행될 수 있다. 여기에 사용되는 정보는 차량에 설치된 각종 센서에 의해 검출되어 전자 제어 유닛으로 전달될 수 있으며, 전자 제어 유닛은 마이크로프로세서, 메모리 및 관련 하드웨어와 소프트웨어를 포함할 수 있다. 마이크로프로세서는 본 발명의 실시예에 따른 요 제어 방법을 수행하도록 프로그램될 수 있다.The yaw control method according to an embodiment of the present invention may be performed by an electronic control unit based on information such as yaw rate, steering angle, steering angular velocity, lateral acceleration, and vehicle speed. Information used herein may be detected by various sensors installed in a vehicle and transmitted to an electronic control unit, and the electronic control unit may include a microprocessor, memory, and related hardware and software. A microprocessor may be programmed to perform a yaw control method according to an embodiment of the present invention.
도 3을 참조하면, 통상적인 노면 마찰계수를 추종하는 주행 안정성 제어가 이루어지는 중 주행 중인 노면이 고마찰 노면인지가 판단된다(S11). 예를 들어, 일반적인 아스팔트 도로는 고마찰 노면으로 판단될 수 있으며, 얼음이나 눈으로 덮인 노면은 저마찰 노면으로 판단될 수 있다. 예를 들어 고마찰 노면인지 여부는 차량의 횡가속도와 종가속도의 벡터 합의 크기와 임계치의 비교를 통해 판단될 수 있으며, 예를 들어 벡터 합이 미리 설정된 임계치보다 작으면 고마찰 노면으로 판단할 수 있다.Referring to FIG. 3 , it is determined whether the driving road surface is a high-friction road surface while driving stability control that follows a normal road surface friction coefficient is performed (S11). For example, a general asphalt road may be determined as a high-friction road surface, and a road surface covered with ice or snow may be determined as a low-friction road surface. For example, whether it is a high-friction road surface can be determined by comparing the magnitude of the vector sum of the lateral acceleration and the longitudinal acceleration of the vehicle with a threshold value. there is.
주행 중인 노면이 고마찰 노면인지 저마찰 노면인지 여부에 따라 과도/부족 조향 기준값을 각각 산정한다(S12, S13). 이는 노면의 마찰 정도에 따라 나머지 조건의 기준값들이 과도/부족 조향 판단에 있어 달라지기 때문이다. 과도/부족 조향 기준값은 조향각, 조향각속도, 횡가속도, 목표 요 레이트와 실제 요 레이트의 차이와 그 변화량 중 하나 이상의 기준값을 포함할 수 있다. 예를 들어, 고마찰 노면인 경우 120도의 조향각에서 50도/s의 조향각속도가 기준값이 될 수 있지만, 저마찰 노면의 경우 보다 더 빠른 제어가 필요하기 때문에 훨씬 낮은 기준값이 산정되어야 한다. 앞에서 설명한 바와 같이, 운전자가 조향각을 작게 하여 오버 스티어를 회피해야 함에도 조향각을 크게 하여 해당 차량의 조향 특성에 의해 오히려 과도한 오버 스티어를 유발하게 하는 것으로 판단할 수 있는 조건이 충족되는 경우 과도 조향으로 판단할 수 있고, 이와 반대로 운전자가 조향각을 더 크게 하여 언더 스티어를 회피해야 함에도 조향각을 유지하거나 작게 하여 과도한 언더 스티어를 유발하게 하는 것으로 판단할 수 있는 조건이 충족되는 경우 부족 조향으로 판단할 수 있다.Depending on whether the driving road surface is a high-friction road surface or a low-friction road surface, excessive/understeering reference values are calculated respectively (S12 and S13). This is because the reference values of the remaining conditions are different in determining over/under steering according to the degree of friction of the road surface. The excessive/understeering reference value may include one or more reference values among a steering angle, a steering angular velocity, a lateral acceleration, a difference between a target yaw rate and an actual yaw rate, and a variation thereof. For example, in the case of a high-friction road surface, a steering angular velocity of 50 degrees/s at a steering angle of 120 degrees can be a reference value, but a much lower reference value must be calculated because faster control is required than in the case of a low-friction road surface. As described above, if the condition that can be judged to cause excessive oversteer by the steering characteristics of the vehicle by increasing the steering angle even though the driver should avoid oversteer by reducing the steering angle is met, it is judged as oversteering. Conversely, if the driver maintains or decreases the steering angle to avoid understeer by making the steering angle larger and the condition for determining that excessive understeer is satisfied, it can be determined as understeering.
노면 조건이 판단되면, 조향각, 조향각속도, 목표 요 레이트와 실제 요 레이트의 차이 및 이의 변화량에 근거하여 조향 모드를 판단한다(S14, S15). 예를 들어, 과도 조향 모드인지를 판단하고(S14), 과도 조향 모드가 아닌 경우 부족 조향 모드인지를 판단한다(S15). 차량의 요와 관련된 주행 정보, 예를 들어 조향각, 조향각속도, 목표 요 레이트와 실제 요 레이트의 차이 및 이의 변화량 등을 기초로 과도 조향 또는 부족 조향 여부를 판단할 수 있다. 앞서 언급한 판단 요소들, 즉 조향각, 조향각속도, 목표 요 레이트와 실제 요 레이트의 차이 및 이의 변화량이 정상 범위를 넘어 과도하다면 과도 조향 모드로 판단할 수 있고 정삼 범위보다 낮아 부족하다면 부족 조향 모드로 판단할 수 있다.When the road surface condition is determined, the steering mode is determined based on the steering angle, the steering angular velocity, the difference between the target yaw rate and the actual yaw rate, and the variation thereof (S14 and S15). For example, it is determined whether it is an excessive steering mode (S14), and if it is not an excessive steering mode, it is determined whether it is an understeering mode (S15). Over-steering or under-steering may be determined based on driving information related to the yaw of the vehicle, for example, a steering angle, a steering angular velocity, a difference between a target yaw rate and an actual yaw rate, and a change amount thereof. If the aforementioned determination factors, that is, the steering angle, steering angular velocity, the difference between the target yaw rate and the actual yaw rate, and their variations are excessive beyond the normal range, it can be determined as excessive steering mode, and if it is insufficient due to lower than the normal range, it can be determined as understeering mode. can judge
예를 들어, 조향각이 미리 설정된 과도 조향 임계 조향각보다 크고, 조향각속도가 미리 설정된 과도 조향 임계 조향각속도보다 크고, 횡가속도가 미리 설정된 과도 조향 임계 횡가속도보다 크고, 목표 요 레이트와 실제 요 레이트의 차이와 그 변화량이 미리 설정된 과도 조향 임계 차이 및 임계 변화량보다 크면, 과도 조향 모드로 판단할 수 있다. 한편, 조향각이 미리 설정된 부족 조향 임계 조향각보다 작고, 조향각속도가 미리 설정된 부족 조향 임계 조향각속도보다 작고, 횡가속도가 미리 설정된 부족 조향 임계 횡가속도보다 작고, 목표 요 레이트와 실제 요 레이트의 차이와 그 변화량이 미리 설정된 부족 조향 임계 차이 및 임계 변화량보다 작으면, 부족 조향 모드로 판단할 수 있다. 또한 목표 요 레이트와 실제 요 레이트의 차이와 그 변화량이 양수로서 커지면 과도 조향 모드로 판단할 수 있고 그 반대이면 부족 조향 모드로 판단할 수 있다. 이러한 요건들을 종합적으로 고려하여 과도/부족 조향 모드를 판단하며 이는 앞에서 언급한 특성 속도 등의 차량의 조향 특성 측정 및 정리 후에 튜닝 요소로 산정될 수 있다.For example, the steering angle is greater than the preset oversteer threshold steering angle, the steering angular velocity is greater than the preset oversteer threshold steering angular velocity, the lateral acceleration is greater than the preset oversteer threshold lateral acceleration, and the difference between the target yaw rate and the actual yaw rate. If and the change amount thereof are greater than the preset threshold difference and threshold change amount of the excessive steering, it may be determined as the excessive steering mode. On the other hand, the steering angle is smaller than the preset under-steering critical steering angle, the steering angular velocity is smaller than the preset under-steering critical steering angular velocity, the lateral acceleration is smaller than the preset under-steering critical lateral acceleration, the difference between the target yaw rate and the actual yaw rate and its If the amount of change is smaller than the preset under-steering threshold difference and the threshold change amount, the under-steering mode may be determined. In addition, if the difference between the target yaw rate and the actual yaw rate and the change amount thereof become large as positive numbers, the excessive steering mode may be determined, and if the opposite is true, the insufficient steering mode may be determined. By comprehensively considering these requirements, the over/under steering mode is determined, which can be calculated as a tuning factor after measuring and arranging the steering characteristics of the vehicle, such as the aforementioned characteristic speed.
S14 단계에서 과도 조향 모드인 것으로 판단되면, 과도 조향 판단을 온(ON) 시키고 제한된 한계 요 레이트 제어 소프트웨어와 교차 제어 소프트웨어로 해당 정보를 전달한다(S16). S15 단계에서 부족 조향 모드인 것으로 판단되면, 부족 조향 판단을 온(ON) 시키고 제안한 한계 요 레이트 제어 소프트웨어와 교차 제어 소프트웨어로 해당 정보를 전달한다(S17). 한편, S14 단계 및 S15 단계에서 과도 조향 모드도 아니고 부족 조향 모드도 아닌 것으로 판단되면, 조향 안정성을 위한 일반적인 제어가 수행된다(S20). 제한된 한계 요 레이트 제어 소프트웨어와 교차 제어 소프트웨어는 뒤에서 설명할 제한된 한계 요 레이트 제어와 교차 제어를 수행하기 위한 것이며, 제한된 한계 요 레이트 제어와 교차 제어에 대해서 뒤에서 다시 설명한다.If it is determined in step S14 that the excessive steering mode is in place, the excessive steering determination is turned on and the corresponding information is transmitted to the limited yaw rate control software and the crossing control software (S16). If it is determined that the steering is insufficient in step S15, the determination of insufficient steering is turned on and the corresponding information is transmitted to the proposed limit yaw rate control software and intersection control software (S17). Meanwhile, when it is determined that neither the over-steering mode nor the under-steering mode is found in steps S14 and S15, general control for steering stability is performed (S20). The limited limit yaw rate control software and crossover control software are for performing the limited limit yaw rate control and crossover control to be described later, and the limited limit yaw rate control and crossover control will be described later.
또한 조향 모드의 판단 후에는 해당 모드에서의 최소 기준값, 즉 임계치 대비 제한된 목표 요 레이트와 실제 요 레이트의 차이가 미리 설정된 값보다 크면 해당 모드가 유지되고 작다면 해당 모드가 해제될 수 있다. 즉, 과도 조향 모드인 경우 노면 한계 요 레이트와 실제 요 레이트의 차이가 과도 조향 유지를 위한 최소 임계치보다 큰지가 판단되고(S18), 판단 결과가 긍정이면 과도 조향 모드를 유지하고 판단 결과가 부정이면 과도 조향 모드를 해제하고 일반적 제어가 수행된다(S20). 유사하게, 부족 조향 모드인 경우 노면 한계 요 레이트와 실제 요 레이트의 차이가 부족 조향 유지를 위한 최소 임계치보다 큰지가 판단되고(S19), 판단 결과가 긍정이면 부족 조향 모드를 유지하고 판단 결과가 부정이면 부족 조향 모드를 해제하고 일반적 제어가 수행된다(S20).In addition, after determining the steering mode, if the minimum reference value in the corresponding mode, that is, the difference between the limited target yaw rate and the actual yaw rate against the threshold is greater than a preset value, the corresponding mode is maintained, and if it is small, the corresponding mode may be released. That is, in the case of the excessive steering mode, it is determined whether the difference between the road surface limit yaw rate and the actual yaw rate is greater than the minimum threshold for maintaining the excessive steering (S18), and if the determination result is positive, the excessive steering mode is maintained and if the determination result is negative The transient steering mode is released and general control is performed (S20). Similarly, in the case of insufficient steering mode, it is determined whether the difference between the road surface limit yaw rate and the actual yaw rate is greater than the minimum threshold for maintaining insufficient steering (S19), and if the determination result is positive, the insufficient steering mode is maintained and the determination result is negative If the low-level steering mode is released, general control is performed (S20).
도 4는 특정 시점에서 앞에서 기술한 정보들과 실제 값을 비교하여 과도 조향 판단과 부족 조향 판단을 온(ON)하는 예를 각각 보여준다. 요 레이트가 과도 조향 시에는 판단 시점에서의 기준 목표 요 레이트보다 크고 부족 조향 시에는 훨씬 작은 형태가 된다. 이 판단이 온 되면 뒤에서 기술한 제한된 한계 요 레이트 제어와 교차 제어가 작동된다.4 shows an example of turning on (ON) the over-steering determination and the under-steering determination by comparing the above-described information and the actual value at a specific time point, respectively. The yaw rate becomes larger than the reference target yaw rate at the time of judgment in case of over steering and much smaller in case of under steering. When this judgment is turned on, the limited yaw rate control and crossing control described later are operated.
과도 조향으로 인한 오버 스티어 발생 또는 부족 조향으로 인한 언더 스티어 발생 시에 조향각을 작게 하거나 크게 하여 이를 회피하는 관점에서 전동 파워 스티어링 시스템(EPS)에 반대 방향의 보상 전류를 인가하는 형태의 협조 제어를 사용할 수도 있다. 본 발명에서는 전자식 안정성 제어를 통해, 과도/부족 조향에 따른 급격한 요 레이트의 변화를 제어한다. 과도 조향은 목표 요 레이트보다 과도한 요 레이트가 발생한 것인 반면 부족 조향은 실제 요 레이트가 훨씬 못 미치는 값이 발생한 경우이다. 부족 조향 모드는 과도 조향 모드와 반대되는 모드이고 이하에서는 과도 조향을 기준으로 설명한다. 부족 조향 모드 판단 시에 다른 점은 앞서 기술한 것처럼 훨씬 부족한 요 레이트가 발생한 상황이기 때문에 과도 조향과는 다르게 목표 한계 요 레이트는 부족한 정도에 따라 과도 조향과는 다르게 비율적으로 커지는 방향으로 결정된다는 점이다.In order to avoid oversteer due to excessive steering or understeer due to understeer by reducing or increasing the steering angle, a cooperative control in the form of applying compensation current in the opposite direction to the electric power steering system (EPS) can be used. may be In the present invention, rapid change in yaw rate due to over/under steering is controlled through electronic stability control. Over-steering occurs when a yaw rate that exceeds the target yaw rate occurs, while under-steering occurs when a value far below the actual yaw rate occurs. The under-steering mode is opposite to the over-steering mode and will be described below based on over-steering. The difference in determining the understeering mode is that, unlike oversteering, the target limit yaw rate is determined in a proportionally larger direction, unlike oversteering, depending on the degree of insufficiency, because a much lower yaw rate has occurred as described above. am.
과도 조향은 급격한 요 모멘트를 유발하기 때문에, 이는 운전자의 선회 의지보다 과도한 선회력이 발생한 것을 의미한다. 이로 인한 스핀 아웃이나 롤 오버(roll over) 현상 등은 차량의 안정성을 무너뜨려 위험한 상황을 초래할 수 있다. 본 발명은 과도 조향에 따른 요 모멘트의 변화를 제어함으로써 이러한 상황을 회피할 수 있게 한다. 운전자의 의지가 고려된 애커만 요 레이트에 비해 실제 요 레이트가 급격하게 변화할 경우, 운전자의 조향 의지가 고려된 목표 요 레이트, 예를 들어 애커만 요 레이트는 제한된 형태로 제어하는 것이 일반적이다. 이러한 경우 차속, 노면 마찰계수, 횡가속도 등을 고려하여, 해당 주행/선회 상황에서의 제한된 요 레이트를 결정할 수 있다. 이는 운전자 조향 의지를 그대로 반영한 요 레이트와 실제 요 레이트의 차이를 기반으로 하는 것이 아니며 제한된 요 레이트와 실제 요 레이트의 차이로 제어된다는 것을 의미한다. 최대의 또는 제한된 목표 요 레이트를 기준으로 할 때에는 목표 요 레이트를 실제 요 레이트가 넘어가지 않아도 제한된 목표 요 레이트를 넘어가는 상황이 발생할 수 있기 때문에, 선제적으로 안정성을 저하시킬 수 있는 상황을 제어하는 형태를 취할 수 있다. 이러한 제한된 목표 요 레이트는 앞에서 설명한 바와 같이 차속, 횡가속도, 마찰계수의 함수로서 다음 수학식 5에 따라 제어될 수 있다.Since excessive steering causes a rapid yaw moment, this means that excessive turning force is generated rather than the driver's intention to turn. Spin-out or roll-over caused by this may cause a dangerous situation by destroying the stability of the vehicle. The present invention makes it possible to avoid this situation by controlling the change of the yaw moment due to excessive steering. When the actual yaw rate rapidly changes compared to the Ackerman yaw rate in which the driver's intention is taken into account, it is common to control the target yaw rate in consideration of the driver's steering intention, for example, the Ackerman yaw rate in a limited form. In this case, a limited yaw rate in a corresponding driving/turning situation may be determined in consideration of vehicle speed, road surface friction coefficient, lateral acceleration, and the like. This means that it is not based on the difference between the yaw rate reflecting the driver's steering intention and the actual yaw rate, but is controlled by the difference between the limited yaw rate and the actual yaw rate. When based on the maximum or limited target yaw rate, a situation in which the target yaw rate may exceed the limited target yaw rate may occur even if the actual yaw rate does not exceed the target yaw rate, so preemptively controlling situations that may deteriorate stability can take shape. As described above, the limited target yaw rate is a function of vehicle speed, lateral acceleration, and friction coefficient and may be controlled according to Equation 5 below.
Figure PCTKR2023002779-appb-img-000005
Figure PCTKR2023002779-appb-img-000005
여기서 TGYLimited는 제한된 목표 요 레이트이고, ay는 횡가속도(단위 g)이고, μ는 마찰계수이고, V는 차속이다.where TGY Limited is the limited target yaw rate, a y is the lateral acceleration (unit g), μ is the coefficient of friction, and V is the vehicle speed.
이러한 제한된 목표 요 형태로 제어가 이루어지면, 차량이 급격하게 쏠리면서 급격한 요가 발생할 경우 제한된 목표 요와 실제 요와의 차이에 따른 제어가 이루어진다. 제한된 목표 요와 실제 요의 차이 값은 앞에서 기술한 오버/언더 스티어의 과도/부족 조향에 따른 특정 임계값 기준과 비교된다. 즉 제한된 목표 요와 실제 요의 차이값이 해당 임계값보다 크거나 작은지 여부에 따라 오버/언더 스티어가 판단된다. 오버 스티어로 보면 과도 조향 여부를 판단하고 이에 따라 결정된 기준 임계값과 앞서 언급한 차이값 등을 고려하여 판단할 수 있다.When control is performed in the form of such a limited target yaw, when a sudden yaw occurs as the vehicle rapidly leans, control is performed according to the difference between the limited target yaw and the actual yaw. The difference value between the limited target yaw and the actual yaw is compared with a specific threshold criterion according to over/under steering of over/under steer described above. That is, over/under steer is determined depending on whether the difference between the limited target yaw and the actual yaw is greater or less than a corresponding threshold value. In terms of oversteer, it is possible to determine whether oversteering is performed and to determine whether the vehicle is oversteered, taking into consideration the reference threshold value determined accordingly and the aforementioned difference value.
제한된 요 레이트는 횡가속도에 기반하여 결정될 수 있으며, 횡가속도가 클수록 제한된 요 레이트도 커질 수 있다. 이때, 제한된 요 레이트를 계산함에 있어서 횡가속도의 움직임을 그대로 반영할 경우 제한된 요 레이트의 형태는 운전자의 조향 의지(조향각과 조향각속도) 및 운전자가 의도한 조향성/경향성 대비 왜곡될 수 있다. 따라서 과도 조향에서 제한된 요의 형태가 운전자 조향 의지 및 조향성 등을 고려하여 운전자가 이질감을 느끼지 않도록 하는 형태로 제어되는 것이 바람직하다. 즉, 횡가속도 기반으로 제어를 하되 운전자가 선회 시 이질감을 느끼지 않도록 목표 요 레이트의 경향성을 추종하여 급격한 요의 변곡점으로 인한 요의 흔들림을 최소화하면서도 기존의 제한된 목표 요 레이트와 같이 선제적으로 제어 가능한 크기로 조정되기 때문에 안정성과 조향성 측면이 모두 고려될 수 있다. 즉 횡가속도 및 마찰계수/차속에 따른 비율로서 다음의 수학식 6에 따라 제한된 목표 요 레이트를 결정하되 목표 요 레이트의 경향성을 추종하도록 하여 보다 부드러운 조향감을 가지게 할 수 있다.The limited yaw rate may be determined based on the lateral acceleration, and the greater the lateral acceleration, the greater the limited yaw rate. At this time, when the motion of the lateral acceleration is reflected as it is in calculating the limited yaw rate, the shape of the limited yaw rate may be distorted compared to the driver's steering intention (steering angle and steering angular velocity) and the steering ability/tendency intended by the driver. Therefore, it is preferable that the shape of the yaw limited in the over-steering is controlled in such a way that the driver does not feel a sense of heterogeneity in consideration of the driver's steering intention and steering ability. In other words, while controlling based on lateral acceleration, the tendency of the target yaw rate is followed so that the driver does not feel a sense of heterogeneity when turning, minimizing the shaking of the yaw due to the rapid inflection point of the yaw, and preemptively controllable like the existing limited target yaw rate. Since it is adjusted in size, both stability and steering aspects can be considered. That is, a limited target yaw rate as a ratio according to lateral acceleration and friction coefficient/vehicle speed is determined according to Equation 6 below, but a tendency of the target yaw rate is followed so as to have a smoother steering feel.
Figure PCTKR2023002779-appb-img-000006
Figure PCTKR2023002779-appb-img-000006
여기서 TGYLimited는 제한된 목표 요(limited yaw)이고, ay는 횡가속도(단위 g)이고, μ는 마찰계수이고, V는 차속이다.where TGY Limited is the limited target yaw, a y is the lateral acceleration (unit g), μ is the coefficient of friction, and V is the vehicle speed.
도 5를 참조하면, 횡가속도의 움직임에 따른 제한된 목표 요 레이트를 만들 경우, 급격한 변곡점이 발생할 수 있고 조향성 측면에서 운전자의 의지와 맞지 않는 부분이 발생할 수 있으며 이로 인한 이질감이 야기될 수 있다. 반면, 횡가속도 등을 고려하되 수학식 6에 기술된 함수 형태에 따라 제한된 목표 요 레이트가 결정되면, 조향의 경향성 및 형태를 따라가면서도 급격한 변곡점이나 일부 왜곡된 요의 제한 형태가 최소화된다. 이러한 제어 방법은 과도 조향 상황에서의 안정성과 조향성을 모두 고려하기에 더 효과적인 방법으로 이해될 수 있다. 이러한 제한된 요에 따른 제어 형태는 차속, 마찰계수, 횡가속도의 움직임과 조향 상황 혹은 조향 의지 등에 따라 다이나믹하게 해당 비율이 변한다. 이때 비율은 튜닝 인자로 구성될 수 있다. 도 5에 나타난 바와 같이, 본 발명의 실시예에 따른 제한된 목표 요에 의해 횡가속도 기반하는 제한된 목표 요에 비해 목표 요에 더 유사한 경향상을 갖는다는 것을 알 수 있고, 도 5의 하단 부분에 나타난 바와 같이 과도 조향 판단에 따른 제한된 목표 요에 따른 전륜 유압 제어가 이루어질 수 있다.Referring to FIG. 5 , when a limited target yaw rate according to the movement of lateral acceleration may occur, a sudden inflection point may occur and a part may occur that does not match the driver's will in terms of steering, resulting in a sense of heterogeneity. On the other hand, if the limited target yaw rate is determined according to the form of the function described in Equation 6 while considering the lateral acceleration, the sudden inflection point or the limited shape of some distorted yaw is minimized while following the tendency and shape of steering. This control method can be understood as a more effective method in consideration of both stability and steering in an oversteering situation. In the control form according to this limited yaw, the ratio dynamically changes according to the movement of the vehicle speed, friction coefficient, and lateral acceleration, and the steering situation or steering intention. In this case, the ratio may be composed of a tuning factor. As shown in FIG. 5, it can be seen that the limited target yaw according to the embodiment of the present invention has a tendency more similar to the target yaw than the limited target yaw based on lateral acceleration, shown in the lower part of FIG. As described above, front-wheel hydraulic pressure control may be performed according to a limited target yaw according to excessive steering determination.
전자 안정성 제어(ESC)의 동작과 관련하여 민감 동작이 이슈화되곤 하며, 이와 관련하여 본 발명에 따른 제한된 목표 요는 보다 유연한 제어 방법을 제시한다. 일반적인 슬라럼(slalom)이나 큰 선회 등의 선회 및 주행에서는 제한 목표 요의 비율은 애커만 요, 즉 운전자의 의지를 나타내는 목표 요와 큰 차이를 만들지 않는다. 그 이유는 단계적으로 과도/부족 조향으로 갈수록 그에 맞춰 다이나믹하게 제한된 목표 요가 만들어지기 때문이다. 이를 위해서는 중립 조향이 아닌 과도/부족 조향 상황에 대한 판단이 중요하다. 또한 과도/부족 조향 내에서도 그 정도에 따라 레벨화되어 있기 때문에, 그 정도에 맞춘 비율로서 목표 요를 제한한다. 이러한 제한된 목표 요의 동작을 통해, 민감 동작이나 과도 조향 정도에 따른 제어의 개입과 제동력의 정도를 보다 유연하게 조정할 수 있다. 즉 일반적인 조향에서는 민감 동작의 문제를 발생시키지 않으면서 과도한 조향으로 갈수록 이에 맞게 다이나믹하게 제한된 목표 요를 만들어 제어한다. 도 6은 이러한 본 발명의 실시예에 따른 제한 요의 비율 변화의 제어의 개념을 도시하며, 다양한 차량 요에 따라 동적으로 제한된 목표 요가 만들어진다는 것을 보여준다.In relation to the operation of the electronic stability control (ESC), a sensitive operation is often an issue, and in this regard, the limited target yaw according to the present invention suggests a more flexible control method. In turning and driving such as general slalom or large turning, the ratio of the limited target yaw does not make a big difference from the Ackerman yaw, that is, the target yaw representing the driver's will. The reason for this is that the more over/under steering in stages, the dynamically limited target yaw is created accordingly. To this end, it is important to judge over/under steering situations rather than neutral steering. In addition, since it is leveled according to the degree even within the over/under steering, the target yaw is limited as a ratio tailored to the degree. Through this limited target yaw operation, it is possible to more flexibly adjust the degree of control intervention and braking force according to the degree of sensitive operation or excessive steering. That is, in general steering, a target yaw dynamically limited to suit the excessive steering is created and controlled without causing a problem of sensitive operation. 6 shows the concept of controlling the change in the ratio of the limiting yaw according to the embodiment of the present invention, and shows that the target yaw is dynamically limited according to various vehicle yaws.
도 7의 (a) 및 (b)는 과도 조향 판단 및 부족 조향 판단 시에 제한된 목표 요의 동적인 변화를 각각 보여준다. 이때, 도 7을 참조하면, 본 발명의 실시예에 따른 제한된 한계 요 레이트는 한계 요 레이트, 즉 목표 요 레이트와 동일한 위상을 갖는 상태로 비율로 조정된다. 전환 후 조향각이 전환 전에 비해 훨씬 커지거나 훨씬 작아질 경우, 이에 맞춰 과도 조향에서의 제한된 목표 요는 훨씬 더 작아지도록 변화되고 부족 조향에서는 훨씬 더 커지게 변화될 수 있다. 이처럼 각각의 판단에 따라 그리고 전환 시 좌우의 비대칭적인 조향에서도 그에 맞추어 제한된 목표 요는 동적으로 조정될 수 있다. 이때 동적으로 조정하는 비율 및 정도는 조향각, 조향각속도, 횡가속도를 바탕으로 과도 조향 시 더 강한 제어가 필요하다고 판단되면 더욱 제한된 목표 요의 비율로 줄이고 부족 조향에서는 반대로 비율을 더욱 올려서 커지도록 변화를 유도할 수 있다. 즉 조향 상황에 따라 대칭/비대칭적으로 동적으로 비율을 변경하면서 제한된 목표 요가 만들어질 수 있다.7 (a) and (b) respectively show the dynamic change of the limited target yaw at the time of over-steering determination and under-steering determination. At this time, referring to FIG. 7 , the limited yaw rate according to the embodiment of the present invention is adjusted in proportion to the limit yaw rate, that is, in a state of having the same phase as the target yaw rate. If the steering angle after switching becomes much larger or much smaller than before switching, the limited target yaw in oversteering may be changed to be much smaller and much larger in understeering accordingly. As such, the limited target yaw can be dynamically adjusted according to each judgment and even in asymmetric left and right steering at the time of conversion. At this time, based on the steering angle, steering angular velocity, and lateral acceleration, the ratio and degree of dynamic adjustment are reduced to a more limited target yaw ratio when it is determined that stronger control is required during oversteering, and in the case of understeering, the ratio is increased to increase the change. can induce That is, a limited target yaw can be created while dynamically changing the ratio symmetrically/asymmetrically according to the steering situation.
고속에서 과도 조향 등에 따라 발생하는 요 레이트의 급격한 변화는 1차적으로는 앞서 기술한 비율로서 제한된 요의 선제적인 움직임에 따른 제어를 통해 줄어들게 되어 차량의 안정성이 제고될 수 있다. 그러나 과도 조향의 정도에 따라 이러한 제어만으로는 한계를 가질 수 있기 때문에, 본 발명에서는 제한된 목표 요에 맞춰 1차적으로 제어한 요 레이트에서 남아 있는 움직임이 차량의 안정성을 여전히 저하시킬 수 있다고 판단되면 전환 메커니즘을 통해 2차적 제어에 의해 요 레이트를 보다 안정시킬 수 있도록 제어한다.The sudden change in yaw rate caused by excessive steering at high speed is primarily reduced by controlling the preemptive movement of the limited yaw at the rate described above, so that the stability of the vehicle can be improved. However, since such control alone may have limitations depending on the degree of excessive steering, in the present invention, if it is determined that the remaining movement at the yaw rate primarily controlled according to the limited target yaw can still deteriorate the stability of the vehicle, the switching mechanism Through the secondary control, the yaw rate is controlled to be more stable.
일반적으로 과도 조향 등으로 인해 발생한 오버 스티어가 1차적으로 제어된 후 조향 방향을 전환하면 앞서 제어한 결과에 해당하는 남아있는 요 레이트가 존재한다. 즉 여전히 제한된 목표 요와 실제 요 사이의 차이가 차량의 안정성을 저하시킬 수 있을 만큼 잔존할 경우, 전환 시 여전히 차량의 안정성을 저해하여 스핀 아웃 되거나 롤이 발생하여 차량의 불안정성을 야기할 수 있다.In general, when the steering direction is switched after oversteer caused by excessive steering is primarily controlled, there is a remaining yaw rate corresponding to the previously controlled result. That is, if the difference between the still limited target yaw and the actual yaw remains enough to degrade vehicle stability, the vehicle may spin out or roll to cause instability of the vehicle during conversion.
ESC를 통한 차량 안정성 제어는 솔레노이드 밸브의 작동 제어를 통해서 이루어지는데 솔레노이드 밸브를 구동하기 위한 전류 신호의 인가와 실제 압력 생성 사이에 일정한 지연(latency)이 존재한다. 즉 제어 및 지령 상으로는 전환 후 앞에서 언급한 위험한 상황을 고려하여 제어를 위한 압력을 생성시키려 하여도 이러한 지연으로 인해 실제 압력은 보다 늦게 생성되어 급격한 요를 제어해야 할 타이밍을 놓칠 수 있다. 이러한 지연을 고려하고 보다 더 빠른 응답성을 확보하여 전환 후에 발생할 수 있는 오버 스티어 상황을 제어하기 위한 전환 메커니즘이 필요하다.Vehicle stability control through the ESC is performed through operation control of the solenoid valve, and there is a certain latency between application of a current signal for driving the solenoid valve and actual pressure generation. That is, in terms of control and command, even if an attempt is made to generate pressure for control in consideration of the above-mentioned dangerous situation after conversion, the actual pressure is generated later due to this delay, and the timing to control rapid yaw may be missed. A transition mechanism is needed to account for this delay and ensure faster responsiveness to control oversteer situations that may occur after transition.
도 8은 앞서 기술된 제한된 목표 요에 기반한 제어 후에 여전히 차량의 안정성을 위협할 수 있는 남아 있는 요가 전환 동작 후에 문제를 야기할 수 있을 때 제시된 전환 메커니즘에 의해 요가 점선 형태로 최소화되는 것을 보여준다. 전환 구간 기준 전후에서 외측 전륜의 브레이크 압력을 통한 제어가 교차하면서 이루어지는 것을 알 수 있다. 앞서 전륜의 제어를 통해 요의 급격한 변화를 최소화하였으나 잔존하는 요가 전환 후 문제를 야기할 수 있기 때문에 이러한 교차 구간 내에서 다음 전륜의 브레이크 압력이 미리 생성되어 앞서 언급한 지연 문제 등이 있음에도 이러한 한계점을 극복할 수 있음을 보여준다. 이러한 교차 구간은 과도한 조향에 따른 전환 동작일수록 그 구간의 전체 크기가 커지게 설계된다. 이는 차속 및 횡가속도, 마찰계수와 더불어 요의 변화량에 기초하여 판단된다. 본 발명의 실시예에서 과도/부족 조향 판단이 기본 조건으로 제시되며, 과도/부족 조향 판단이 온(ON) 된 경우에만 교차 제어 메커니즘이 동작된다. 이는 불필요한 교차 제어에 따른 앞선 압력 제어로 인한 민감 동작 및 조향 이질감을 방지하기 위함이다. 또한 본 발명의 실시예에서는 전환 구간의 정의하고 해당 구간에 부합될 때만 교차 제어 메커니즘이 동작된다.Figure 8 shows that the yaw is minimized in dotted line form by the proposed switching mechanism when it can cause problems after the remaining yaw switching motions that can still threaten the stability of the vehicle after control based on the previously described limited target yaw. It can be seen that the control through the brake pressure of the outer front wheel crosses before and after the transition section standard. Although the sudden change in yaw was minimized through the control of the front wheel previously, since the remaining yaw can cause problems after switching, the brake pressure of the next front wheel is generated in advance within this crossing section, and despite the delay problem mentioned above, these limitations are overcome. Show that you can overcome. The crossing section is designed so that the overall size of the section increases as the switching operation occurs due to excessive steering. This is determined based on the amount of change in yaw along with vehicle speed, lateral acceleration, and friction coefficient. In the embodiment of the present invention, over/under steering determination is presented as a basic condition, and the crossover control mechanism is operated only when the over/under steering determination is turned ON. This is to prevent sensitive operation and steering heterogeneity due to advanced pressure control according to unnecessary crossover control. In addition, in the embodiment of the present invention, a transition period is defined and the crossing control mechanism is operated only when the transition period is met.
전환 구간에서는 실제 요와 운전자의 조향에 해당하는 요가 서로 부호가 뒤바뀌면서 변화하기 시작하며, 과도한 전환 조향일 경우 요의 변화량은 급격히 상승하고 이러한 동적 변화가 교차 제어 구간의 판단 기준이 된다. 급격한 전환일수록 실제 요와 조향(목표 요 또는 조향각)의 부호가 다른 구간이 길게 나타난다. 본 발명의 실시예에서는 교차 제어 구간의 시작 구간은 이러한 부호 불일치 구간을 의미한다. 그리고 이러한 시작 구간 후에 연장 구간이 구성된다. 여기서 연장 구간에서 부호는 일치하지만 여전히 요의 변화량이 크고, 횡가속도 및 횡가속도 변화량이 클 경우 교차 제어 구간을 연장한다. 이 연장 구간은 다음 오버 스티어나 언더 스티어 제어가 개시될 때 해제된다. 그리고 이를 더욱 응용하여, 전환 전 오버 스티어 또는 언더 스티어 제어 구간 내에서 부호가 일치하지 않는 구간 내에서 요의 변화량 등이 판단 조건과 맞지 않아 시작 구간에서의 교차 제어 필요를 결정하기 위한 판단이 온 되지 않았더라도 교차 제어 구간이 설정될 수 있다. 이러한 제어 개념이 도 9에 나타나 있다. 도 9의 오른쪽 부분을 참조하면 전환 전 제어에서 교차 제어 시작 구간에서 요 변화량이나 횡가속도 등의 조건이 맞지 않아 교차 제어 판단이 온 되지 않았지만, 이후 전환 구간에서 재차 판단하여 교차 구간을 생성하여 차량의 안정성을 확보하는 형태가 구현된다. 전환 시 노면 불균형이나 조향 상황에 따라 이러한 불안정한 과도 전환 형태도 가능하기 때문에 상황에 맞는 구조가 필요하다. 도 9에서 아래 부분에 있는 화살표는 오버 스티어 상황에서의 전륜 압력을 나타낸다.In the transition section, the actual yaw and the yaw corresponding to the driver's steering begin to change as their signs are reversed. The sharper the turn, the longer the section in which the sign of the actual yaw and the steering (target yaw or steering angle) is different. In the embodiment of the present invention, the start section of the crossing control section means such a code mismatch section. And after this starting section, an extended section is formed. Here, in the extension section, if the signs are identical but the change in yaw is still large and the lateral acceleration and change in lateral acceleration are large, the crossing control section is extended. This extended period is released when the next oversteer or understeer control is initiated. And further applying this, in the section where the signs do not match in the oversteer or understeer control section before switching, the change in yaw does not match the judgment condition, so the decision to determine the need for crossover control in the start section is not turned on. Even if not, the crossing control section may be set. This control concept is shown in FIG. 9 . Referring to the right part of FIG. 9 , in the pre-conversion control, in the crossover control starting section, the crossover control determination was not turned on because the conditions such as yaw change or lateral acceleration were not met, but after that, the crossover control was judged again in the conversion section to create an intersecting section of the vehicle A form that secures stability is implemented. Depending on the road surface imbalance or steering situation at the time of conversion, such an unstable transitional form is also possible, so a structure suitable for the situation is required. In Figure 9, the arrow in the lower part indicates the front wheel pressure in an oversteer situation.
본 발명의 실시예에서는, 설계한 교차 제어 구간에서의 액추에이팅 구조는 이중 구조로 이루어진다. 첫 번째 구간에서는 실제 요와 운전자 조향 의지가 반영된 요의 부호, 즉 방향이 다른지, 이때 오버 스티어(또는 언더 스티어)가 발생하면서 전환되는 것인지, 그리고 요의 변화량이 어떻게 변화하는지가 고려된다. 첫 번째 구간에서는 요 변화량의 기준값, 즉 임계값이 두 번째 구간과 다르게 설정되며 더불어 브레이크 유압 제어를 위한 모터의 속도 제어 및 솔레노이드 밸브 전류도 두 번째 구간과 다르게 설정될 수 있다. 여기서 솔레노이드 밸브의 전류는 브레이크 오일의 압력을 제어하기 위한 것이고 모터는 브레이크 오일의 압력의 증감 속도를 제어하기 위한 것이다.In the embodiment of the present invention, the actuating structure in the designed crossing control section is made of a double structure. In the first section, the actual yaw and the sign of the yaw reflecting the driver's steering intention, that is, whether the direction is different, whether oversteer (or understeer) occurs and is converted, and how the yaw change amount is considered. In the first section, the reference value of the yaw change amount, that is, the threshold value is set differently from that in the second section, and the motor speed control and solenoid valve current for brake hydraulic control may also be set differently from those in the second section. Here, the current of the solenoid valve is for controlling the pressure of the brake oil, and the motor is for controlling the rate of increase or decrease of the pressure of the brake oil.
이는 양 구간 사이에 차이를 두는 구조가 가능하다는 것을 의미한다. 첫 번째 구간은 불필요한 압력 제어에 따른 민감 동작의 문제가 발생하지 않으면서도 전환 후 요의 급격한 변화를 막기 위한 압력을 미리 제공하는 목적을 가지고 상황에 따라 압력 기울기가 선택되어야 한다. 두 번째 구간에서는 압력이 만들어진 후 요의 변화량과 횡가속도 등에 기초하여 훨씬 빠른 압력 생성이 필요한지 여부 등을 판단하여 모터의 제어를 달리하여 압력의 상승 기울기 등을 다시 다르게 할 수 있다. 이러한 이중 구조는 전환 동작에서의 민감 동작의 문제점을 최소화하면서 상황에 맞게 이중 구조 형태로 솔레노이드 밸브 전류 및 모터 속도 제어를 같거나 다르게 할 수 있으며, 이에 의해 여러 조향/선회 상황에 맞춘 튜닝이 가능하다는 장점이 얻어진다. 즉 첫 번째 구간의 결과를 두 번째 구간에서 참고하게 되고 이를 통해 보다 유연한 제어가 가능해진다.This means that a structure with a difference between both sections is possible. In the first section, a pressure gradient should be selected according to the situation with the purpose of providing pressure in advance to prevent a sudden change in yaw after switching without causing a problem of sensitive operation due to unnecessary pressure control. In the second section, after the pressure is created, it is determined whether much faster pressure generation is necessary based on the yaw change and lateral acceleration, etc., and the control of the motor is changed to make the pressure rise slope different again. This dual structure can control the solenoid valve current and motor speed the same or differently in the form of a dual structure according to the situation while minimizing the problem of sensitive operation in the switching operation, thereby enabling tuning tailored to various steering/turning situations. advantage is obtained. That is, the result of the first section is referred to in the second section, and through this, more flexible control is possible.
전환 전 실제 요와 목표하는 운전자의 의지에 기초한 요 사이의 차이가 크다면 그리고 이때의 차이가 생기는 변화량이 크다면, 이 정보를 전환 메커니즘에 전달한다. 만약 그 차이가 크고 이에 대한 미분 값인 변화량도 크다면, 1차 및 2차 구간에서의 모터 속도 제어를 최대로 하고 최대한 빠르게 압력을 만들어 줄 수 있도록 솔레노이드 밸브의 전류를 제어할 수 있다. 반대로, 만약 전환 전의 차이가 작거나 차이에 대한 변화량이 크지 않다면, 과도한 제어를 하여 부작용을 유발하지 않기 위해 필요한 만큼의 모터를 조정하고 밸브의 압력을 조정하여 보다 유연한 전환 제어가 이루어지도록 할 수 있다.If the difference between the actual yaw before switching and the target yaw based on the driver's will is large and the amount of change resulting from the difference is large, this information is transmitted to the switching mechanism. If the difference is large and the amount of change, which is the differential value, is large, the current of the solenoid valve can be controlled to maximize motor speed control in the first and second sections and to create pressure as quickly as possible. Conversely, if the difference before switching is small or the amount of change for the difference is not large, more flexible switching control can be achieved by adjusting the motor and adjusting the valve pressure as necessary so as not to cause side effects by excessive control. .
본 발명의 실시예에 따르면, 오버/언더 스티어 제어를 위한 제어 요소, 예를 들어 각 휠의 브레이킹을 제어하기 위한 솔레노이드 밸브, 모터 및 기타 액추에이터를 서로 교차하도록 제어하며, 이때 복수의 구간으로 분할하여 교차 제어가 이루어진다.According to an embodiment of the present invention, control elements for over/under steer control, for example, solenoid valves, motors, and other actuators for controlling braking of each wheel are controlled to cross each other, and at this time, by dividing into a plurality of sections, Cross control is achieved.
교차 구간 내의 제1 구간에서의 솔레노이드 밸브의 전류 및 모터의 속도 설정값은 다음의 수학식 7에 의해 이루어질 수 있다.The current of the solenoid valve and the speed setting value of the motor in the first section in the crossing section may be made by Equation 7 below.
Figure PCTKR2023002779-appb-img-000007
Figure PCTKR2023002779-appb-img-000007
여기서, TcvCurrent_1st는 제1 구간에서의 솔레노이드 밸브 전류이고, TcvInit_cross는 교차 구간의 초기 솔레노이드 밸브 전류이고, MSpeed_1st는 제1 구간에서의 모터 속도 설정값이고, MInit_cross는 교차 구간의 초기 모터 속도 설정값이고, Yaw_err은 현재 목표 요와 실제 요의 차이이고, YawErr_dot는 Yaw_err의 변화량(미분값)이고, Yaw_err_b는 전환 전의 목표 요와 실제 요의 차이이고, YawErr_dot_b는 Yaw_err_b의 변화량(미분값)이고, ay는 횡가속도(단위 g)이고, μ는 마찰계수이고, V는 차속이다.Here, Tcv Current_1st is the solenoid valve current in the first section, Tcv Init_cross is the initial solenoid valve current in the crossing section, M Speed_1st is the motor speed set value in the first section, and M Init_cross is the initial motor speed in the crossing section. Yaw_err is the difference between the current target yaw and actual yaw, YawErr_dot is the change (differential value) of Yaw_err, Yaw_err_b is the difference between the target yaw and actual yaw before switching, YawErr_dot_b is the change (differential value) of Yaw_err_b , a y is the lateral acceleration (unit g), μ is the coefficient of friction, and V is the vehicle speed.
한편 교차 구간 내의 제2 구간에서의 밸브 및 모터의 설정은 다음의 수학식 8에 의해 이루어질 수 있다.Meanwhile, setting of the valves and motors in the second section in the crossing section may be performed by Equation 8 below.
Figure PCTKR2023002779-appb-img-000008
Figure PCTKR2023002779-appb-img-000008
여기서, TcvCurrent_2nd는 제2 구간에서의 솔레노이드 밸브 전류이고, TcvInit_cross_2nd는 제2 구간의 초기 솔레노이드 밸브 전류이고, TcvCurrent_1st는 제1 구간에서의 솔레노이드 밸브 전류이고, MSpeed_2nd는 제2 구간에서의 모터 속도 설정값이고, MInit_cross_2nd는 제2 구간의 초기 모터 속도 설정값이고, MSpeed_1st는 제1 구간에서의 모터 속도 설정값이고, Yaw_err은 현재 목표 요와 실제 요의 차이이고, YawErr_dot는 Yaw_err의 변화량(미분값)이고, Yaw_err_b는 전환 전의 목표 요와 실제 요의 차이이고, YawErr_dot_b는 Yaw_err_b의 변화량(미분값)이고, ay는 횡가속도(단위 g)이고, μ는 마찰계수이고, V는 차속이다.Here, Tcv Current_2nd is the solenoid valve current in the second section, Tcv Init_cross_2nd is the initial solenoid valve current in the second section, Tcv Current_1st is the solenoid valve current in the first section, and M Speed_2nd is the motor in the second section. speed setting value, M Init_cross_2nd is the initial motor speed setting value of the second section, M Speed_1st is the motor speed setting value in the first section, Yaw_err is the difference between the current target yaw and actual yaw, and YawErr_dot is the amount of change in Yaw_err (differential value), Yaw_err_b is the difference between the target yaw and actual yaw before switching, YawErr_dot_b is the amount of change in Yaw_err_b (differential value), a y is the lateral acceleration (unit g), μ is the friction coefficient, and V is the vehicle speed am.
수학식 7 및 8을 참조하면, 이중 구조, 즉 2개의 구간으로 구성된 교차 구간에서의 솔레노이드 밸브와 모터의 설정값은 전환 전후의 실제 요와 목표 요 사이의 차이와 해당 차이의 변화량을 고려하여 결정되고 또한 현재의 차이와 그에 대한 변화량을 고려하여 결정된다. 제2 구간에서는 제1 구간에서 계산한 솔레노이드 밸브와 모터의 설정값을 추가적으로 고려한다. 한편, 본 발명의 다른 실시예에서는, 추가적으로 보다 민감한 제어가 필요한 경우, 세 개의 단계로 구성되는 3단계 형태의 교차 구조가 적용될 수 있다. 이 경우 중간 단계는 앞뒤의 설정값을 고려한 비례적 함수를 채택할 수 있다.Referring to Equations 7 and 8, the set value of the solenoid valve and the motor in the dual structure, that is, the crossing section composed of two sections, is determined by considering the difference between the actual yaw and the target yaw before and after switching and the amount of change in the difference. It is also determined by considering the current difference and the amount of change therefor. In the second section, the set values of the solenoid valve and motor calculated in the first section are additionally considered. Meanwhile, in another embodiment of the present invention, when more sensitive control is additionally required, a three-step crossover structure consisting of three steps may be applied. In this case, the intermediate step may adopt a proportional function considering the set values of the front and back.
도 10을 참조하면, 이중 구조로 교차 구간을 구성할 경우, 각 구간 단계별로 모터와 솔레노이드 밸브에 대한 속도/전륜 제어값을 동일하거나 다르게 할 수 있음을 알 수 있다. 이러한 유연한 구조는 과도한 제어에 따른 요의 흔들림으로 인한 퓌시 테일링(fish tailing)이나 부족한 제어에 따른 조향감 개선 및 이질감 해소에도 유연한 구조가 된다.Referring to FIG. 10 , it can be seen that when configuring the crossing section in a double structure, the speed/front wheel control values for the motor and the solenoid valve can be the same or different for each section. Such a flexible structure becomes a flexible structure for fish tailing due to shaking of the yaw due to excessive control or improvement of steering feeling and relief of heterogeneity due to insufficient control.
도 11은 본 발명의 실시예에 따른 이중 구조 형태의 교차 구간으로 제어하는 전환 메커니즘의 순서도를 도시하고, 도 12는 본 발명의 실시예에 따른 이중 구조에서 단계별 요 정보에 기초하는 구간별 제어를 보여주는 그래프를 도시한다. 본 발명의 실시예에 따르면, 전환 전의 목표 요(또는 제한된 목표 요)와 실제 요의 차이와 전환 후의 값을 고려하면서 교차 구간을 2단계(또는 3단계) 형태로 차별되게 제어할 수 있는 구조로 인해 유연한 대응이 가능하다.11 is a flow chart of a switching mechanism for controlling cross-sections of a dual structure type according to an embodiment of the present invention, and FIG. 12 shows section-by-section control based on step-by-step yaw information in a dual structure according to an embodiment of the present invention. graph that shows According to an embodiment of the present invention, a structure capable of differentially controlling the intersection section in a two-step (or three-step) form while considering the difference between the target yaw (or limited target yaw) and the actual yaw before conversion and the value after conversion A flexible response is possible.
이중 구조의 교차 제어 구간에서 비례미분 제어의 형태가 사용될 수 있다. 교차 제어 구간에서 비례미분 제어를 사용하는 경우, 제1 구간의 안정성 제어 정보, 예를 들어 요 레이트 정보와 비례미분 정보 등을 제2 구간으로 전달하여 제2 구간의 제어가 이루어진다. 교차 구간에서 비례미분 제어가 적용되면 비례미분 값은 요 정보는 물론 차속, 노면 정보 등이 고려되어 결정될 수 있다.A form of proportional derivative control can be used in the intersection control section of the dual structure. When the proportional derivative control is used in the crossover control interval, control of the second interval is performed by transferring stability control information of the first interval, for example, yaw rate information and proportional derivative information, etc. to the second interval. When the proportional derivative control is applied in the intersection section, the proportional derivative value may be determined considering vehicle speed and road surface information as well as yaw information.
한편, 전환 후 언더 스티어 상황이나 전환 전후에서 오버 스티어와 언더 스티어가 바뀌는 상황이 고려될 수 있다. 이 경우 교차 제어 구간 진입 시 앞에서 설명한 조향 모드 판단과 다른 판단이 이루어져야 한다. 예를 들어, 전환 전에는 과도 조향 모드로 선회하다가 전환 시점에서 매우 늦게 작은 조향각으로 전환되면, 부족 조향 모드로 다시 판단될 수 있다. 즉 예를 들어 전환이 너무 늦어서 목표 요 대비 실제 요의 차이와 그 변화량이 음의 값, 즉 반대 부호의 값으로 나타나서 부족 조향 판단 기준치를 넘으면 부족 조향 판단이 이루어진다. 이 판단 변화는 교차 제어 구간에서 일어날 수 있다. 부족 조향 모드 판단이 이루어지면, 교차 영역에서는 전환 후 언더 스티어 상황을 대비한 내측 후륜의 압력이 단계별로 생성된다. 차량의 슬립으로 드리프트가 발생하여 운전자의 의지대로 조향이 이루어지지 않는 상황이 우려되면 응답성이 중요하게 된다. 따라서 단계별로 교차 구간에서 미리 차량의 내측 후륜의 압력을 만들어 줌으로써 이러한 지연 문제를 또한 해결할 수 있다. 한편 언더 스티어에서 오버 스티어로 변경되면, 오버 스티어 압력을 교차 구간에서 미리 준비할 수 있다. 이와 같이 어떠한 전환 형태에서도 유연하게 차량의 안정성과 조향성/조종성을 고려한 제어가 이루어질 수 있다. 이는 전환 구간 내에서 내부적으로 오버 스티어에서 언더 스티어로의 전환으로 판단되거나 그 반대의 판단이 이루어지면, 이에 근거하여 전륜과 후륜의 압력을 미리 생성할 수 있기 때문이다.Meanwhile, an understeer situation after conversion or a situation in which oversteer and understeer change before and after conversion may be considered. In this case, when entering the intersection control section, a different determination from the previously described steering mode determination must be made. For example, if the vehicle turns in the excessive steering mode before switching and then switches to a small steering angle very late at the time of switching, the understeering mode may be determined again. That is, for example, when the difference between the target yaw and the actual yaw and the change amount appear as negative values, that is, a value of the opposite sign because the conversion is too late, and the understeering determination criterion is exceeded, an understeering determination is made. This change in judgment may occur in the crossing control period. When the understeer mode is determined, pressure on the inner rear wheel is generated step by step in the intersection area to prepare for an understeer situation after switching. Responsiveness becomes important when there is a concern about a situation in which drift occurs due to vehicle slip and steering is not performed according to the driver's will. Therefore, this delay problem can also be solved by creating pressure on the inner rear wheel of the vehicle in advance in the intersection section step by step. On the other hand, when changing from understeer to oversteer, oversteer pressure can be prepared in advance in the intersection. In this way, control considering stability and steering/maneuverability of the vehicle can be performed flexibly in any conversion form. This is because, when it is internally determined that the transition from oversteer to understeer or vice versa is made within the transition period, pressure between the front and rear wheels can be generated in advance based on this determination.
도 13을 참조하면, 전환 후의 요 상황을 고려하면 언더/오버 스티어에 대해 미리 차량 외측 전륜이나 내측 후륜을 위한 제어를 준비할 수 있기 때문에, 전환 후 상황에 보다 유연하게 대처할 수 있다. 교차 구간 내에서 내측 후륜이나 외측 전륜에 준비된 압력이 존재하였는데 그 후 상황에서 오버/언더 스티어가 발생하지 않으면 준비된 내외측 압력이 배출된다. 이는 민감 동작을 고려한 것이며 첫 번째 전환 판단에서 대부분의 민감 동작이 판단되어 처리된다. 오버 스티어, 전환, 오버 스티어 시에는 전륜 좌우 압력과 교차로 제어하고 도 13의 (b)의 예와 같이 오버 스티어, 전환, 언더 스티어 시에는 전환 전에는 전륜 압력 전환구간의 교차 제어 구간부터는 후륜 내측 압력을 제어할 수 있다. 이와 같이 본 발명의 실시예에 따른 교차 제어는 다양하고 보다 유연한 오버/언더 스티어 제어 구조를 제시할 수 있다.Referring to FIG. 13 , considering the yaw situation after conversion, control for the outer front wheel or the inside rear wheel of the vehicle can be prepared in advance for under/oversteer, so that the situation after conversion can be more flexibly dealt with. In the cross section, prepared pressure exists on the inside rear wheel or the outside front wheel, but if over/under steer does not occur in the situation after that, the prepared inside and outside pressure is discharged. This is in consideration of sensitive motions, and most of the sensitive motions are determined and processed in the first conversion decision. In the case of oversteer, transition, and oversteer, the left and right pressure and intersection of the front wheels are controlled, and as shown in the example of FIG. You can control it. As described above, crossover control according to an embodiment of the present invention can provide a variety of more flexible over/understeer control structures.
도 14는 본 발명의 실시예에 따른 과도/부족 조향 모드 판단에 따른 제한된 목표 요 설정 및 교차 제어의 순서도를 도시한다.14 is a flowchart of limited target yaw setting and crossing control according to over/under steering mode determination according to an embodiment of the present invention.
먼저, 앞에서 도 3의 순서도를 참조로 설명한 바와 같이, 과도/부족 조향 판단이 이루어지고(S31), 과도/부족 조향 모드가 유지되는 조건을 충족하는지 여부가 판단된다(S32). 과도/부족 조향 모드의 유지 조건이 충족되지 않는 경우 일반적 오버/언더 스티어 제어가 이루어진다(S33).First, as described above with reference to the flowchart of FIG. 3, over/under steering determination is made (S31), and it is determined whether or not a condition for maintaining the over/under steering mode is satisfied (S32). When the maintenance condition of the over/under steering mode is not satisfied, general over/under steer control is performed (S33).
한편, 과도/부족 조향 모드의 유지 조건이 충족된 경우, 제한된 목표 요를 설정한다(S34). 그리고 나서, 교차 제어의 필요 여부가 판단된다(S35). 교차 제어의 필여 여부는 앞에서 설명한 바와 같이 이루어질 수 있다. 교차 제어가 필요하지 않은 것으로 판단되면, 다시 과도/부족 조향 모드의 유지 조건이 충족되는지 여부를 판단한다(S36). S36 단계에서 과도/부족 조향 모드의 유지 조건이 충족되지 않는 것으로 판단되면, 일반적인 오버/언더 스티어 제어가 이루어지고(S33), S단계에서 과도/부족 조향 모드의 유지 조건이 충족되는 것으로 판단되면, 제한된 목표 요에 따른 오버/언더 스티어 제어가 이루어진다(S37).Meanwhile, when the condition for maintaining the over/under steering mode is satisfied, a limited target yaw is set (S34). Then, it is determined whether crossover control is necessary (S35). Whether or not crossing control is required may be made as described above. If it is determined that crossover control is not required, it is determined again whether the condition for maintaining the excessive/understeering mode is satisfied (S36). If it is determined that the condition for maintaining the over/under steering mode is not satisfied in step S36, general over/under steer control is performed (S33), and when it is determined that the condition for maintaining the over/under steering mode is satisfied in step S, Over/under steer control is performed according to the limited target yaw (S37).
한편, S35 단계에서 교차 제어가 필요한 것으로 판단되면, 교차 제어 구간을 설정한다(S38). 이때, 앞에서 설명한 바와 같이, 교차 제어 구간은 두 개의 구간, 즉 제1 및 제2 구간으로 구분될 수 있고, 각 구간에서의 제어 값이 설정될 수 있다.Meanwhile, if it is determined that crossover control is necessary in step S35, a crossover control section is set (S38). In this case, as described above, the crossing control section may be divided into two sections, that is, a first section and a second section, and a control value in each section may be set.
그리고 나서, 앞에서 설명한 바와 같이, 액추에이터, 모터 및 솔레노이드 밸브 등의 제어를 통해 제1 구간에서의 교차 제어를 수행하고(S39), 이어서 제2 구간에서의 교차 제어를 수행한다(S40). 이때, 제2 구간에서 제1 구간의 처리 결과를 참조하여 필요 시에 앞서 결정된 값을 변경할 수 있다.Then, as described above, crossover control is performed in the first section through control of actuators, motors, solenoid valves, etc. (S39), and then crossover control is performed in the second section (S40). At this time, the previously determined value may be changed by referring to the processing result of the first section in the second section, if necessary.
도 15는 본 발명의 실시예에 따른 제어 방법에 의해 급격한 전환 조향 후 요 제어의 결과를 보여주는 그래프를 도시한다. 도 15에 나타난 바와 같이 실제 차량에서 급격한 전환 조향 후 요의 안정적 제어 상황을 통해 본 발명의 제한된 목표 요와 전환 메커니즘에 의한 제어 성능의 향상을 확인할 수 있다. 도 15에 나타난 바와 같이, 급격한 전환 조향이 있을 때 상황에 맞는 노면 한계 요를 만들고 "A" 지점에서 단계적 구조를 통해 전환 후의 급격한 조향으로 인한 과도한 요가 예측되면 이를 저감시키기 위한 압력이 "A" 지점부터 앞서의 압력과 서로 교차하면서 출력된다. 이를 통해 "B" 지점에서 크게 증가했을 요가 실제로는 안정적인 수준으로 제어되며 이 후 "C" 지점에서 요가 큰 요동 없이 안정적으로 제어되고 그에 의해 직진 주행이 무리 없이 가능해짐을 알 수 있다.15 is a graph showing the result of yaw control after sudden changeover steering by the control method according to an embodiment of the present invention. As shown in FIG. 15, it is possible to confirm the improvement in control performance by the limited target yaw and switching mechanism of the present invention through a stable control situation of yaw after rapid steering in an actual vehicle. As shown in FIG. 15, when there is a sharp turn steering, a road surface limit yaw suitable for the situation is made, and if excessive yaw due to sudden steering after the change is predicted through a step-by-step structure at point "A", the pressure to reduce it is applied at point "A" It is output while crossing each other with the previous pressure. Through this, it can be seen that the yaw, which would have greatly increased at point "B", is actually controlled to a stable level, and then, at point "C", the yaw is stably controlled without large fluctuations, thereby enabling straight driving without difficulty.
도 16은 본 발명의 실시예에 따른 정현파 형태의 노면 한계 요와 전환 메커니즘을 통한 요 제어의 결과를 보여주는 그래프를 도시한다. 도 16은 빠른 전환으로 반대 방향으로 선회 시의 상황에서의 실제 차량 성능을 나타내는 그래프를 도시하며, 안정적인 요 제어가 이루어짐을 보여준다. 본 발명은 노면에 따른 정현파 형태의 한계 요와 더불어 급격한 전환 동작에서의 단계적인 제어 방법을 제시한다. 소위 문제가 되는 ESC의 민감 동작 등의 측면에서도 매우 유연한 구조가 제시되며, 위의 전환 메커니즘은 차량의 주행/선회 상황에 맞게 동작하여 교차가 깊게 이루어지는 전환도 가능하도 이 보다 얕은 수준의 교차도 가능하다. 또한 제어가 필요하지 않은 상황이면, 교차 압력 구조가 작동하지 않기 때문에 민감 동작 이슈 등에 보다 유연한 구조가 제시된다.16 is a graph showing the result of yaw control through a sinusoidal road limit yaw and a switching mechanism according to an embodiment of the present invention. FIG. 16 shows a graph showing actual vehicle performance in a situation when turning in the opposite direction with a quick change, and shows that stable yaw control is achieved. The present invention proposes a step-by-step control method in an abrupt switching operation along with a sine wave type limit yaw according to the road surface. A very flexible structure is proposed even in terms of sensitive operation of the ESC, which is a so-called problem, and the above switching mechanism operates according to the driving/turning situation of the vehicle, enabling deep crossing conversion as well as shallower crossing. do. In addition, since the cross pressure structure does not operate in situations where control is not required, a more flexible structure is proposed for sensitive operation issues.
이상에서 본 발명의 실시예를 설명하였으나, 본 발명의 권리범위는 이에 한정되지 아니하며 본 발명의 실시예로부터 본 발명이 속하는 기술분야에서 통상의 지식을 가진 자에 의해 용이하게 변경되어 균등한 것으로 인정되는 범위의 모든 변경 및 수정 형태를 포함한다.Although the embodiments of the present invention have been described above, the scope of the present invention is not limited thereto, and it is recognized that the embodiments of the present invention are easily changed by those skilled in the art to which the present invention belongs and are equivalent. It includes all changes and modifications within the scope of
본 발명은 차량의 요 제어 방법에 관한 것으로 차량의 주행 제어에 적용될 수 있으므로 산업상 이용가능성이 있다.The present invention relates to a method for controlling the yaw of a vehicle, and has industrial applicability since it can be applied to driving control of a vehicle.

Claims (6)

  1. 고마찰 노면에 대한 과도 조향 기준값 및 부족 조향 기준값과 저마찰 노면에 대한 과도 조향 기준값과 부족 조향 기준값을 각각 설정하는 단계,Setting over-steering reference values and under-steering reference values for the high-friction road surface and over-steering reference values and under-steering reference values for the low-friction road surface, respectively;
    차량의 요와 관련된 주행 정보와 상기 과도 조향 기준값 및 상기 부족 조향 기준값을 기초로 과도 조향 또는 부족 조향 여부를 판단하는 단계, 그리고Determining whether to over-steer or under-steer based on driving information related to the yaw of the vehicle, the over-steering reference value, and the under-steering reference value; and
    상기 과도 조향 또는 상기 부족 조향인 것으로 판단되는 경우 미리 결정된 한계 요 레이트와 동일한 위상을 유지하면서 비율이 조정된 제한된 한계 요 레이트에 따라 요 레이트를 제어하는 단계Controlling the yaw rate according to the limited limit yaw rate whose ratio is adjusted while maintaining the same phase as the predetermined limit yaw rate when it is determined that the over-steering or the under-steering
    를 포함하는 차량의 요 제어 방법.Yaw control method of a vehicle comprising a.
  2. 제1항에 있어서,According to claim 1,
    상기 과도 조향 기준값과 상기 부족 조향 기준값은 조향각, 조향각속도, 횡가속도, 목표 요 레이트와 실제 요 레이트의 차이 및 이의 변화량 중 하나 이상의 기준값을 각각 포함하는 요 제어 방법.The excessive steering reference value and the understeering reference value each include one or more reference values of a steering angle, a steering angular velocity, a lateral acceleration, a difference between a target yaw rate and an actual yaw rate, and a variation thereof.
  3. 제1항에 있어서,According to claim 1,
    상기 과도 조향 또는 상기 부족 조향인 것으로 판단되는 경우 오버/언더 스티어 제어를 위해 각 휠의 브레이킹의 제어를 위한 복수의 제어 요소를 서로 교차하도록 제어하는 교차 제어를 수행하는 단계를 더 포함하고,When it is determined that the over-steering or the under-steering is performed, cross-over control is performed to control a plurality of control elements for controlling braking of each wheel to cross each other for over/under-steer control;
    상기 교차 제어는 복수의 교차 구간으로 구분되어 이루어지고,The crossing control is divided into a plurality of crossing sections,
    상기 교차 구간의 안정성 제어를 위한 정보가 다음 교차 구간으로 전달되어 사용되도록 구성되는 요 제어 방법.Yaw control method configured such that the information for stability control of the crossing section is transmitted to the next crossing section and used.
  4. 제3항에 있어서,According to claim 3,
    상기 교차 구간은 과도한 조향에 따른 전환 동작일수록 전체 크기가 커지도록 설계되는 요 제어 방법.The yaw control method in which the crossing section is designed so that the overall size increases as the switching operation according to excessive steering.
  5. 제3항에서,In paragraph 3,
    상기 교차 구간의 안정성 제어를 위한 정보는 요 레이트 정보와 비례미분 정보를 포함하는 오버/언더 스티어 제어 방법.The information for controlling the stability of the intersection section includes yaw rate information and proportional derivative information.
  6. 고마찰 노면에 대한 과도 조향 기준값 및 부족 조향 기준값과 저마찰 노면에 대한 과도 조향 기준값과 부족 조향 기준값을 각각 설정하는 단계,Setting over-steering reference values and under-steering reference values for the high-friction road surface and over-steering reference values and under-steering reference values for the low-friction road surface, respectively;
    차량의 요와 관련된 주행 정보와 상기 과도 조향 기준값 및 상기 부족 조향 기준값을 기초로 과도 조향 또는 부족 조향 여부를 판단하는 단계,Determining whether to over-steer or under-steer based on driving information related to the yaw of the vehicle, the over-steering reference value, and the under-steering reference value;
    상기 과도 조향 또는 상기 부족 조향인 것으로 판단되는 경우 미리 결정된 한계 요 레이트를 조정하여 얻어지는 제한된 한계 요 레이트에 따라 요 레이트를 제어하는 단계, 그리고Controlling a yaw rate according to a limited limit yaw rate obtained by adjusting a predetermined limit yaw rate when it is determined that the over-steering or the under-steering is performed; and
    상기 과도 조향 또는 상기 부족 조향인 것으로 판단되는 경우 오버/언더 스티어 제어를 위해 각 휠의 브레이킹의 제어를 위한 복수의 제어 요소를 서로 교차하도록 제어하는 교차 제어를 수행하는 단계를 포함하고,When it is determined that the over-steering or the under-steering is performed, crossing control is performed to control a plurality of control elements for controlling braking of each wheel to cross each other for over/under steer control,
    상기 교차 제어는 복수의 교차 구간으로 구분되어 이루어지고,The crossing control is divided into a plurality of crossing sections,
    상기 교차 구간의 안정성 제어를 위한 정보가 다음 교차 구간으로 전달되어 사용되도록 구성되는 차량의 요 제어 방법.The yaw control method of a vehicle configured to transmit and use information for stability control of the intersection section to a next intersection section.
PCT/KR2023/002779 2022-03-04 2023-02-28 Method for controlling yaw of vehicle WO2023167485A1 (en)

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