CN117775106B - Rear wheel steering working mode switching control method, vehicle controller and vehicle - Google Patents
Rear wheel steering working mode switching control method, vehicle controller and vehicle Download PDFInfo
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Abstract
The invention discloses a rear wheel steering working mode switching control method, a vehicle controller and a vehicle thereof, belonging to the technical field of vehicles, wherein the control method comprises the following steps: firstly, acquiring a signal of a rear wheel steering system, and judging whether a switching condition of a working mode is met or not according to the signal; when the switching condition of the working mode is met, starting mode switching timing; after starting the mode switching timing, judging whether the mode switching timing accumulation exceeds a preset time threshold value; when the mode switching timing accumulation exceeds a preset time threshold, the step of switching the working modes is executed, so that reasonable transition between the working modes under different driving working conditions can be realized, unstable rear wheel steering operation caused by frequent switching between the different working modes is avoided, and the vehicle steering performance is reduced and even the vehicle is in dangerous driving working conditions caused by the unstable rear wheel steering operation, thereby effectively improving the vehicle steering stability and being suitable for the vehicle with a rear wheel steering system.
Description
Technical Field
The invention relates to the technical field of vehicles, in particular to a rear wheel steering working mode switching control method, a vehicle controller and a vehicle thereof.
Background
With the continuous improvement of the intelligent degree of vehicles, chassis electric control systems are also more and more complex, and rear wheel steering systems which are only equipped on advanced vehicles in the past are more and more appeared on class-C vehicles and even class-B vehicles in recent years. According to the specific running requirements of the vehicle, the rear wheel steering can provide different working modes, and the running working conditions of the vehicle need to be switched between the corresponding rear wheel steering working modes; however, in the related art, frequent switching between different modes is liable to occur to affect the steering stability of the vehicle.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems existing in the prior art. Therefore, the invention provides a rear wheel steering working mode switching control method, which can realize stable transition between different working modes of rear wheel steering and improve vehicle steering stability.
The invention further provides a vehicle controller and a vehicle comprising the vehicle controller.
The rear wheel steering operation mode switching control method according to the first aspect of the embodiment of the invention is applied to a vehicle with a rear wheel steering system, and comprises the following steps:
acquiring a signal of the rear wheel steering system, and judging whether a switching condition of an operating mode is met according to the signal, wherein the signal comprises a current operating mode of the rear wheel steering system, an operating mode switching request and an operating state of a rear wheel steering actuator;
when the switching condition of the working mode is met, controlling to start mode switching timing;
and when the mode switching timing accumulation exceeds a preset time threshold, executing switching of the working mode of the rear wheel steering system.
The rear wheel steering working mode switching control method provided by the embodiment of the invention has at least the following beneficial effects:
Firstly, acquiring signals of a rear wheel steering system, wherein the signals comprise a current working mode of the rear wheel steering system, a working mode switching request and a working state of a rear wheel steering actuator, and judging whether the switching condition of the working mode is met or not according to the signals; when the switching condition of the working mode is met, starting mode switching timing, and immediately executing the switching of the working mode at the moment; after starting the mode switching timing, judging whether the mode switching timing accumulation exceeds a preset time threshold value; when the mode switching timing accumulation exceeds a preset time threshold, the step of switching the working modes is executed, so that reasonable transition between the working modes under different driving working conditions can be realized, unstable rear wheel steering operation caused by frequent switching between the different working modes is avoided, and the vehicle steering performance is reduced and even the vehicle is in dangerous driving working conditions caused by the unstable rear wheel steering operation, thereby effectively improving the vehicle steering stability and being suitable for the vehicle with a rear wheel steering system.
According to some embodiments of the invention, the operating modes of the rear wheel steering system include a first operating mode in which the steering of the rear wheels and the front wheels of the vehicle is opposite, and a second operating mode in which the steering of the rear wheels and the front wheels of the vehicle is the same; the executing switching the working mode of the rear wheel steering system comprises the following steps:
and switching the working mode of the rear wheel steering system into the first working mode or the second working mode.
According to some embodiments of the invention, the vehicle further has a vehicle stability control system, and the determining whether the switching condition of the operation mode is satisfied according to the signal includes:
when the vehicle stability control system intervenes in working and sends out a working mode switching request, and the last control period of rear wheel steering is the first working mode or the non-working state, judging that the switching condition of the working mode is met;
the executing switching the working mode of the rear wheel steering system comprises the following steps:
and switching the working mode of the rear wheel steering system to the second working mode.
According to some embodiments of the invention, the vehicle further has an intelligent driving system, and the determining whether the switching condition of the operation mode is satisfied according to the signal further includes:
When the intelligent driving system intervenes in working and sends out a working mode switching request, and the last control period of rear wheel steering is the second working mode or the non-working state, judging that the switching condition of the working mode is met;
the executing switching the working mode of the rear wheel steering system comprises the following steps:
and switching the working mode of the rear wheel steering system to the first working mode.
According to some embodiments of the invention, the control method further comprises:
When the mode switching timing accumulation does not exceed the preset time threshold, repeatedly executing the judgment of whether the switching condition of the working mode is met according to the signal;
when the switching condition of the working mode is met, controlling to start mode switching timing, including:
and controlling the mode switching timing to increase a control period until the control period is accumulated to exceed the preset time threshold.
According to some embodiments of the invention, the control method further comprises:
And when the switching condition of the working mode is not met, controlling not to switch the working mode of the rear wheel steering system, and maintaining the current working state of the rear wheel steering actuator.
According to some embodiments of the invention, the control method further comprises:
And acquiring the driving condition of the vehicle, and determining the preset time threshold according to the driving condition.
According to some embodiments of the invention, the obtaining the driving condition of the vehicle, and determining the preset time threshold according to the driving condition, includes:
Acquiring a working mode switching request, a current vehicle speed, a current steering wheel rotation angle and a rotation angle speed of the rear wheel steering system;
And selecting the corresponding preset time threshold according to the working mode switching request, the current vehicle speed, the current steering wheel rotation angle and the rotation angle speed.
A vehicle controller according to a second aspect of an embodiment of the invention, which is applied to a vehicle having a rear-wheel steering system, includes:
the signal acquisition module is used for acquiring signals of the rear wheel steering system, wherein the signals comprise a current working mode of the rear wheel steering system, a working mode switching request and a working state of a rear wheel steering actuator;
The condition judging module is used for judging whether the switching condition of the working mode is met according to the signal, and controlling to start mode switching timing when the switching condition of the working mode is met;
and the rear steering execution module is used for executing the switching of the working mode of the rear wheel steering system when the mode switching timing accumulation exceeds a preset time threshold.
The vehicle controller according to the embodiment of the invention has at least the following beneficial effects:
The vehicle controller acquires signals of the rear wheel steering system through the signal acquisition module, and then judges whether the switching conditions of the working modes are met or not according to the signals by the condition judgment module; when the switching condition of the working mode is met, starting mode switching timing, and immediately executing the switching of the working mode at the moment; after starting the mode switching timing, judging whether the mode switching timing accumulation exceeds a preset time threshold value; when the mode switching timing accumulation exceeds a preset time threshold, the rear steering execution module executes the step of switching the working modes, so that reasonable transition between the working modes under different driving conditions can be realized, unstable rear wheel steering operation caused by frequent switching between the different working modes is avoided, the vehicle operability is reduced and even the vehicle is in dangerous driving conditions, the vehicle operation stability is effectively improved, and the method is suitable for vehicles with rear wheel steering systems.
A vehicle according to a third aspect of an embodiment of the present invention includes the vehicle controller according to the second aspect of the above embodiment.
Because the vehicle adopts all the technical schemes of the vehicle controller in the above embodiments, the vehicle controller at least has all the beneficial effects brought by the technical schemes in the above embodiments, and the description thereof is omitted.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 is a flow chart of a rear-wheel steering operation mode switching control method according to an embodiment of the present invention;
FIG. 2 is a flowchart showing a specific example of a rear-wheel-steering operation mode switching control method according to an embodiment of the present invention;
FIG. 3 is a flowchart illustrating a step of switching from a first operation mode to a second operation mode according to an embodiment of the present invention;
FIG. 4 is a flowchart illustrating a step of switching the second operation mode to the first operation mode according to an embodiment of the present invention;
FIG. 5 is a schematic diagram illustrating a switching between a first operation mode and a second operation mode according to an embodiment of the present invention;
FIG. 6 is a flowchart illustrating steps for determining a predetermined time threshold in accordance with one embodiment of the present invention;
Fig. 7 is a schematic block diagram of a vehicle controller according to an embodiment of the present invention.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.
In the description of the present invention, it should be understood that the azimuth or positional relationship indicated by the terms upper, lower, etc. are based on the azimuth or positional relationship shown in the drawings, and are merely for convenience of description and simplification of the description, and are not indicative or implying that the apparatus or element in question must have a specific azimuth, be constructed and operated in a specific azimuth, and thus should not be construed as limiting the present invention.
In the description of the present invention, plural means two or more, and greater than, less than, exceeding, etc. are understood to not include the present number, and the above, below, within, etc. are understood to include the present number. The description of the first and second is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.
In the description of the present invention, it should be noted that terms such as arrangement, installation, connection, etc. should be construed broadly, and those skilled in the art may reasonably determine the specific meaning of the foregoing terms in the present invention in combination with the specific content of the technical solution.
The following description of the embodiments of the present invention will be made with reference to the accompanying drawings, in which it is apparent that the embodiments described below are some, but not all embodiments of the invention.
Because the vehicle can easily generate oversteer when turning at a high speed, the running danger caused by oversteer can be compensated through the rear wheel steering system, and meanwhile, for medium-large-sized vehicles and luxury vehicles, the rear wheel steering can lead the vehicle to be more flexible at a low speed and more stable at a high speed, so that the driving is also full of fun.
The rear wheel steering has two conditions of the same direction and the reverse direction with the front wheel, the same direction increases the understeer, and the reverse direction increases the oversteer. When the vehicle is running at a low speed, oversteer can be appropriately increased by reverse rotation of the rear wheels and the front wheels. When a vehicle running at a high speed encounters an emergency lane change, the vehicle is easy to oversteer without the help of any electronic auxiliary system, and the oversteer tendency can be compensated by generating a steering in the same direction as the front wheels through the rear wheels, so that the vehicle has better balance.
Rear wheel steering is currently mainly achieved in two ways, one by a mechanical structure and the other by an electric motor or hydraulic power. For large luxury vehicles, the continuously lengthened wheelbase brings good comfortable riding space in the vehicle, but the wheelbase also has a certain negative effect on the operability of the vehicle. Both the turning radius at low speeds and the stability at high speeds are compromised. The influence on the running characteristics of the vehicle after the wheelbase is increased can be made up by adding the rear wheel steering system, and meanwhile, a luxury vehicle has good driving fun.
At present, the technology content of the rear wheel steering system is mainly concentrated on a control system, and when the rear wheel steering system works, the rear wheel steering system needs to receive various dynamic driving signals of a vehicle, then comprehensively judges and outputs an appropriate steering angle, and any calculation error can possibly cause the vehicle to lose control, especially when the vehicle runs at a high speed.
In the related art, the rear wheel steering actuator may perform the rear wheel steering target value transmitted by the auxiliary driving system when the rear wheel steering function is turned on, thereby completing the rear wheel steering control, by the driver being able to control the turning on and off of the rear wheel steering function. However, the switch is only used for controlling the rear wheel steering function, and does not relate to different working modes when the rear wheel steering function is started, and a switching transition mode between the different working modes is also not provided, so that frequent switching between the different modes is easy to occur to influence the steering stability of the vehicle.
The embodiment of the invention provides a rear wheel steering working mode switching control method, which can realize stable transition between different working modes, ensure the stability of the rear wheel steering working, avoid unstable rear wheel steering caused by frequent switching between different working modes and improve the steering stability of a vehicle.
A rear-wheel steering operation mode switching control method according to an embodiment of the present invention, which is applicable to a vehicle having a rear-wheel steering system, will be described with reference to fig. 1 to 6, and the control method will be described below with specific examples.
Referring to fig. 1, the rear wheel steering operation mode switching control method includes, but is not limited to, the steps of:
Step S100, acquiring a signal of a rear wheel steering system, and judging whether a switching condition of an operating mode is met according to the signal, wherein the signal comprises a current operating mode of the rear wheel steering system, an operating mode switching request and an operating state of a rear wheel steering actuator;
Step S200, when the switching condition of the working mode is met, controlling to start mode switching timing;
Step S300, when the mode switching timing accumulation exceeds a preset time threshold, the working mode of the rear wheel steering system is switched.
It can be understood that, since the rear wheels of the vehicle have different working modes, the vehicle switches the working modes according to different driving road conditions, the current working mode of the rear wheel steering system and the working state of the rear wheel steering actuator need to be known before switching operation, whether the current road condition requirement is met or not can be judged through the current working mode, and whether the rear wheel steering actuator is in a normal working state or not is judged; and under the condition that the current working mode does not meet the current road condition, sending a working mode switching request to the rear wheel steering system to request the switching of the working mode.
That is, whether the switching condition of the working mode is satisfied is determined according to the current working mode of the rear wheel steering system, the working mode switching request and the working state of the rear wheel steering actuator, and when the current working mode does not satisfy the current road condition, the rear wheel steering actuator is in the normal working state and the working mode switching request is received, the switching condition of the working mode is determined to be satisfied, and at this time, the above step S200 is continuously executed; otherwise, when the switching condition of the working mode is not satisfied, the current working mode is maintained. When the current working mode meets the current road condition requirement, the rear wheel steering actuator is abnormal or fails, the working mode switching request is not received, and the like, the switching condition of the working mode can be judged not to be met.
Referring to fig. 1, in step S200, when the switching condition of the operation mode is satisfied, the operation of switching the operation mode is not directly performed, but the mode switching timing is started, and after the mode switching timing is started, it is determined whether the mode switching timing accumulation exceeds the preset time threshold; when the mode switching timing accumulation exceeds the preset time threshold, the step of switching the working mode is executed, that is, when the switching condition of the working mode is met, the accumulation exceeds the preset time threshold, the working mode switching operation is executed only if the accumulation is further met, otherwise, the switching operation is not executed.
It can be understood that the starting point of the accumulated time is the moment point when the switching condition of the working mode is met, and the accumulated time is compared with the preset time threshold in the accumulating process to judge whether the preset time threshold is exceeded. Specifically, after the mode switching timing is started, judging whether the current accumulated mode switching timing T_change is greater than a preset time threshold T_thre; if the accumulated switching timer T_change is greater than the preset time threshold T_thre, the switching operation mode is performed. The preset time threshold may be set to 3s, 5s, 8s, etc. according to the actual requirement, for example, the preset time threshold may be set to 5s, and when the accumulated mode switching timer t_change > 5s, the execution of switching the operation mode is controlled.
It can be understood that if the rear wheel steering system immediately performs the switching of the operation mode when the switching condition of the operation mode is satisfied, the problem that the operation of the vehicle is affected by frequent switching between different modes easily occurs, for example, the rear wheel steering and the front wheel are in the same direction in the current operation mode, and when the switching condition of the operation mode is satisfied, the immediate switching to the mode in which the rear wheel steering and the front wheel are in the opposite direction causes unreasonable mode transition, the unstable condition occurs in the vehicle, and frequent switching between the rear wheel steering and the front wheel in the same direction and in the opposite direction easily occurs, thereby affecting the steering stability of the vehicle.
According to the rear wheel steering working mode switching control method, the mode switching timing is increased between the moment when the switching condition of the working mode is judged to be met and the moment when the switching operation is executed, the mode switching timing can be understood to be a buffer time period, the switching of the working mode is not executed immediately in the buffer time period, and the operation of switching the working mode is executed after the accumulation of the mode switching timing exceeds the preset time threshold, so that reasonable transition between the working modes under different driving working conditions can be realized, the transition is stable, unstable rear wheel steering working caused by frequent switching between the different working modes is avoided, the vehicle operability is reduced and even the vehicle is in dangerous driving working conditions due to the fact, and the vehicle steering stability is effectively improved.
It will be appreciated that the rear wheel steering is similar to the front wheel steering in that the rear wheel steering can perform steering angles in both left and right directions, and in the embodiment in which the rear wheel steering system has two modes of operation, the first mode is the opposite of the rear wheel steering to the front wheel steering, and is referred to as a first mode of operation, when the rear wheel steering is opposite to the front wheel steering, the yaw gain of the vehicle can be increased, the turning radius of the vehicle can be reduced, and the maneuverability and flexibility of the vehicle can be improved, so that the mode of operation in which the rear wheel steering opposite to the front wheel steering is performed can also be referred to as an agility control mode; the second mode is the same as the front wheel steering mode, and is called a second operation mode, in which the rear wheel steering and the front wheel steering are the same when the vehicle is running at a high speed, and the understeer tendency of the vehicle is enhanced, and the stability of the vehicle is improved, and is also called a stability control mode. That is, the rear wheel steering has two operation modes of an agility control mode and a stability control mode.
In the step S300, the step of executing the switching of the operation mode of the rear wheel steering system specifically includes:
step S310, the operation mode of the rear wheel steering system is switched to the first operation mode or the second operation mode.
Specifically, the current working mode is a first working mode, and when the switching condition of the working mode is met and the mode switching timing accumulation exceeds a preset time threshold, the switching from the first working mode to the second working mode is controlled; the current working mode is a second working mode, and when the switching condition of the working mode is met and the mode switching timing accumulation exceeds a preset time threshold, the second working mode is controlled to be switched to the first working mode.
It can be appreciated that the first mode of operation is applicable to situations where the vehicle is traveling at a low radius, or where oversteer is properly increased by reverse rotation of the rear and front wheels while the vehicle is traveling at a low speed; the second working mode is suitable for a scene that the vehicle runs at a high speed, and the oversteer trend can be compensated through the steering of the rear wheels and the front wheels in the same direction, so that the vehicle has better balance. Therefore, the vehicle needs to switch between the first operation mode and the second operation mode under the above-described different driving conditions.
Referring to fig. 2, it should be noted that in the embodiment of the present invention, the vehicle controller performs the above steps, and the vehicle controller controls to complete the switching of the working modes according to different driving conditions, specifically, the vehicle controller may obtain the current working mode of the rear wheel steering system, the switching request of the working mode, and the working state of the rear wheel steering actuator, and determine whether the switching condition of the working mode is satisfied according to the above signals; when the working mode switching condition is met, the mode switching timing is started, and then when the accumulated timing T_change meets the preset time threshold T_thre, the switching action of the rear wheel steering working mode is executed, so that the stable transition between different working modes of the rear wheel steering is realized, and the influence on the steering stability of the vehicle caused by frequent switching between different modes is avoided.
In the embodiment, the vehicle is further provided with a vehicle stability control system and an intelligent driving system, wherein the vehicle stability control system is used for restraining the sideslip of the rear wheels, the sideslip of the front wheels and the brake folding phenomenon of the tractor from occurring in sudden situations such as abrupt steering operation or abrupt road surface condition change through four-wheel independent automatic pressurization brake control and engine torque control, so that the stability of running of the vehicle is ensured. The vehicle stability control system is generally composed of various sensors such as a wheel speed sensor, a yaw sensor for monitoring the dynamics of an automobile, a lateral and front-rear acceleration sensor, a steering angle sensor for monitoring the operation of a driver, a hydraulic sensor, and a hydraulic actuator capable of actively braking and hydraulically pressurizing four wheels. The principle is that the sideslip of the front wheel or the rear wheel is detected, and the braking force and the engine torque are controlled to stabilize the direction of the automobile during running. Such sideslip is determined by a target yaw rate obtained from a steering angle of a driver, an actual yaw rate detected by a sensor mounted on an automobile, a body sideslip angle, and the like.
The intelligent driving system mainly comprises three links of network navigation, autonomous driving and manual intervention, wherein related audiovisual signals and signals can be obtained through sensors, and corresponding follow-up systems are controlled through cognitive calculation. The network navigation of the intelligent driving system solves the problems of where, which lane in which road to walk, and the like; the autonomous driving is to complete driving behaviors such as lane keeping, overtaking and lane combining, red light stopping, green light running, whispering interaction and the like under the control of an intelligent system; the manual intervention is that the driver responds to the actual road condition under a series of prompts of the intelligent system. The intelligent driving system integrates the functions of advanced signal control technology, scenario environment sensing, multi-level auxiliary driving and the like.
Referring to fig. 3, in some embodiments, the rear wheel steering operation mode switching control method includes, but is not limited to, the following steps:
Step S110, when the vehicle stability control system intervenes in working and sends out a working mode switching request, and the last control period of the rear wheel steering is a first working mode or a non-working state, judging that the switching condition of the working mode is met;
step S210, when the switching condition of the working mode is met, controlling to start mode switching timing;
Step S311, when the mode switching timing accumulation exceeds the preset time threshold, the working mode of the rear wheel steering system is switched to the second working mode.
It can be understood that the condition for switching the agility control mode to the stability control mode is that the vehicle stability control system is in operation and issues a rear wheel steering stability control request, and the previous control period of the rear wheel steering is the agility control mode or the rear wheel steering is not in operation.
Since the vehicle stability control system is involved in operation in the course of vehicle steering, particularly in the case of a small vehicle turning radius, in order to maintain the stability of the vehicle turning, whether the vehicle stability control system is involved in operation is one of the judgment switching conditions. In addition, the state of the rear wheel steering in the last control period is also determined, and whether the rear wheel steering is in an agility control mode or an unoperated state is judged; it is understood that if the state of the rear wheel steering in the last control period is the stability control mode, the switching operation need not be performed.
As can be understood from fig. 2 and fig. 5, when the switching condition of the working mode is satisfied, the mode switching timing is started, and after the working mode switching timing is started, whether the current accumulated mode switching timing t_change is greater than the preset time threshold t_thre is determined; if the accumulated mode switching timing T_change is greater than a preset time threshold T_thre, switching to a stability control mode; if the accumulated mode switching timer t_change is less than or equal to the preset time threshold t_thre, step S110 is re-executed to determine whether the switching condition of the operation mode is satisfied. The process of switching the agility control mode into the stability control mode can be smoothly transitioned, unstable rear wheel steering caused by frequent switching between the agility control mode and the stability control mode is avoided, and the steering stability of the vehicle is effectively improved.
Referring to fig. 4, in some embodiments, the rear wheel steering operation mode switching control method includes, but is not limited to, the following steps:
Step S120, when the intelligent driving system intervenes in working and sends out a working mode switching request, and the last control period of the rear wheel steering is a second working mode or a non-working state, judging that the switching condition of the working mode is met;
step S220, when the switching condition of the working mode is met, controlling to start mode switching timing;
Step S312, when the mode switching timing accumulation exceeds the preset time threshold, the operation mode of the rear wheel steering system is switched to the first operation mode.
It can be understood that the condition that the stability control mode is switched to the agility control mode is that the intelligent driving system intervenes to work and sends out a rear wheel steering agility control request, and the previous control period of the rear wheel steering is the stability control mode or the rear wheel steering is not working, so that the intelligent driving system is suitable for the working condition that the vehicle runs at a high speed. And taking whether the intelligent driving system intervenes in the operation or not as one of judging switching conditions. In addition, the state of the rear wheel steering in the last control period is determined, and whether the rear wheel steering is in a stability control mode or an unoperated state is judged; it is understood that if the state of the rear wheel steering in the last control period is the agility control mode, the switching operation need not be performed.
As can be understood from fig. 2 and fig. 5, when the switching condition of the working mode is satisfied, the mode switching timing is started, and after the working mode switching timing is started, whether the current accumulated mode switching timing t_change is greater than the preset time threshold t_thre is determined; if the accumulated mode switching timing T_change is greater than a preset time threshold T_thre, switching to an agility control mode; if the accumulated mode switching timer t_change is less than or equal to the preset time threshold t_thre, step S110 is re-executed to determine whether the switching condition of the operation mode is satisfied. Therefore, the process of switching the stability control mode into the agility control mode can be smoothly transited, unstable rear wheel steering caused by frequent switching between the agility control mode and the stability control mode is avoided, and the steering stability of the vehicle is effectively improved.
In some embodiments, the rear wheel steering operation mode switching control method further includes the steps of:
step S320, when the mode switching timing accumulation does not exceed the preset time threshold, repeatedly executing the judgment of whether the switching condition of the working mode is satisfied according to the signal;
In step S330, the control mode switching timer increases the control period until the control period is accumulated to exceed the preset time threshold.
It can be appreciated that the preset time threshold has a certain time interval, and the specific set value is not too large or too small, so that the stable transition between the two working modes can be satisfied. If the preset time is too long, the switching of the working mode is delayed, and the driving feeling is affected; if the preset time is too short, the problem of frequent switching between working modes cannot be solved. The operation of switching the working modes is executed only after the mode switching timing accumulation exceeds the preset time threshold, so that the stable transition between the working modes under different driving working conditions can be realized, unstable steering operation of the rear wheel caused by frequent switching between the different working modes is avoided, the vehicle operability is reduced and even the vehicle is in dangerous driving working conditions caused by the unstable steering operation, and the vehicle operation stability is effectively improved.
As can be understood from fig. 2, if the accumulated mode switching timer t_change is less than or equal to the preset time threshold t_thre, the process returns to step S100, if the working mode switching condition is still satisfied, a control period t_circle is added to the accumulated mode switching timer t_change, and then it is determined whether the accumulated mode switching timer exceeds the preset time threshold, so that the above steps are repeatedly performed. It should be noted that, the control period t_circle may be understood as a time for executing the step S320 and the step S330, and may specifically be 1S, 2S, or the like.
In some embodiments, the rear wheel steering operation mode switching control method further includes the steps of:
And step S400, when the switching condition of the working mode is not met, controlling not to switch the working mode of the rear wheel steering system, and maintaining the current working state of the rear wheel steering actuator.
It can be understood that if the working mode switching condition is not satisfied, it means that the current working mode satisfies the requirement of the driving working condition, and the working mode does not need to be switched, so that the working mode of steering after not being switched is directly decided, and the current state is maintained unchanged.
In some embodiments, the rear wheel steering operation mode switching control method further includes the steps of:
Step S500, a driving condition of the vehicle is obtained, and a preset time threshold is determined according to the driving condition.
Specifically, because different driving conditions are matched with different rear wheel steering working modes, different working modes can be provided for rear wheel steering according to specific running requirements of the vehicle, and the corresponding working modes also need to be switched when the running conditions of the vehicle are changed.
Considering that the agility control mode is generally suitable for a low-speed running scene of a vehicle, the stability control mode is generally suitable for a high-speed running scene, different switching conditions need to be met when the agility control mode and the stability control mode are switched, and the preset time thresholds required under different working conditions are also different. That is, the preset time threshold required for switching the agility control mode to the stability control mode may take a different value from the preset time threshold required for switching the stability control mode to the agility control mode.
Based on this, before the step of determining whether the mode switching timing exceeds the preset time threshold, it is necessary to acquire the driving condition of the vehicle, for example, by acquiring the current vehicle speed to determine whether the vehicle is in a high-speed driving state, thereby determining the driving condition of the vehicle, and then the preset time threshold may be determined according to the driving condition. For example, the corresponding preset time threshold value can be determined through preset parameters under the high-speed driving condition, and the specific operation can be that the driving condition of the vehicle is obtained, and when the driving condition is the high-speed driving condition, the pre-stored threshold value corresponding to the high-speed driving condition is called and taken as the preset time threshold value.
Referring to fig. 6, in some embodiments, the specific operation steps of the step S500 include:
step S510, acquiring a working mode switching request, a current vehicle speed, a current steering wheel angle and a steering angle speed of a rear wheel steering system;
Step S520, selecting a corresponding preset time threshold according to the working mode switching request, the current vehicle speed, the current steering wheel rotation angle and the rotation angle speed.
It may be understood that the preset time threshold t_thre is not a fixed value, and the preset time threshold t_thre of the post-rotation operation mode is different under different driving conditions, in an embodiment, the preset time threshold is determined according to signals such as a specific operation mode switching request, a current vehicle speed, a current steering wheel rotation angle and a rotation angle speed, and the like.
The current vehicle speed, the current steering wheel angle and the steering angle speed can be respectively obtained through the sensors, and it can be understood that the current operation of a driver can be judged through the current steering wheel angle and the steering angle speed, so that the current driving condition can be determined by combining the working mode switching request and the current vehicle speed, and further the preset time threshold can be determined.
In some embodiments, after the working mode switching request, the current vehicle speed, the current steering wheel rotation angle and the rotation angle speed are obtained, a preset time threshold corresponding to the current driving condition can be obtained through a table look-up mode according to the working mode switching request, the current vehicle speed, the current steering wheel rotation angle and the rotation angle speed, so that the step of judging whether the mode switching timing exceeds the preset time threshold can be performed. When the working mode switching condition is met, the mode switching timing is started, and then when the accumulated time timing T_change meets the preset time threshold T_thre, the switching action of the working modes is executed, so that the stable transition between different working modes of the rear wheel steering is realized, and the influence on the steering stability of the vehicle due to frequent switching between different working modes is avoided.
Referring to fig. 7, the embodiment of the invention further provides a vehicle controller, and fig. 7 shows a schematic block structure of the vehicle controller. The vehicle controller may execute the rear-wheel steering operation mode switching control method provided in the above embodiment, and specifically, the vehicle controller includes a signal acquisition module, a condition judgment module, and a rear-wheel steering execution module.
The signal acquisition module is used for acquiring signals of the rear wheel steering system, wherein the signals comprise a current working mode of the rear wheel steering system, a working mode switching request and a working state of a rear wheel steering actuator;
The condition judging module is used for judging whether the switching condition of the working mode is met according to the signals, and controlling to start mode switching timing when the switching condition of the working mode is met;
And the rear steering executing module is used for executing the switching of the working mode of the rear wheel steering system when the mode switching timing accumulation exceeds a preset time threshold.
Referring to fig. 2, describing a specific example, first, a signal acquisition module acquires a signal of a current operation mode, an operation mode switching request, an operation state of a rear wheel steering actuator, and the like, and then a condition judgment module judges whether an operation mode switching condition is satisfied according to the acquired signal.
If the backward working mode switching condition is judged to be met, starting mode switching timing; if the working mode switching condition is not met, directly deciding to not switch the working mode of the rear wheel steering, and maintaining the current state unchanged.
When the working mode switching timing is started, judging whether the current accumulated mode switching timing T_change is larger than a preset time threshold T_thre or not; if the accumulated mode switching timing T_change is greater than a preset time threshold T_thre, the rear steering executing module executes the switching of the rear steering working mode; if the accumulated mode switching timing T_change is less than or equal to the preset time threshold value T_thre, the signal acquisition module re-acquires the corresponding signal, the condition judgment module re-executes the step of judging whether the working mode switching condition is met, and if the working mode switching condition is still met, a control period T_circle is added to the accumulated switching timing T_change;
Specifically, the conditions for switching the agility control mode to the stability control mode are: the vehicle stability control system intervenes in operation and sends out a rear wheel steering stability control request, and the rear wheel steering is in an agility control mode or the rear wheel steering is not operated in a control period.
Conditions for switching the stability control mode to the agility control mode: the intelligent driving system intervenes in work and sends out a rear wheel steering agility control request, and the rear wheel steering is in a stability control mode or the rear wheel steering is not operated in a control period.
In addition, the preset time threshold T_thre of the working mode under different driving working conditions is also different, and the actual vehicle test calibration determination is required according to signals such as a specific working mode switching request, a current vehicle speed, a current steering wheel rotation angle and rotation angle speed.
Because the switching operation is not immediately executed when the working mode switching condition is met, the operation of switching the working mode is executed after the mode switching timing accumulation exceeds the preset time threshold, so that reasonable transition between the working modes under different driving working conditions can be realized, the transition is stable, unstable rear wheel steering caused by frequent switching between the different working modes is avoided, the reduction of vehicle operability caused by the unstable rear wheel steering is avoided, even the vehicle is in dangerous driving working condition, and the vehicle operation stability is effectively improved.
The vehicle controller according to the embodiment of the present invention has a processor and a memory for storing instructions that, when executed by the processor, perform the rear wheel steering operation mode switching control method of the above embodiment.
The processor and memory in the vehicle controller may be connected by a bus, for example. The memory, as a non-transitory computer readable storage medium, may be used to store non-transitory software programs as well as non-transitory computer executable programs. In addition, the memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk memory, flash memory device, or other non-transitory solid state storage device. In some embodiments, the memory optionally includes memory remotely located relative to the control processor, which may be connected to the controller via a network.
The non-transitory software programs and instructions required to implement the control methods of the above embodiments are stored in the memory, and when executed by the processor, the control methods of the above embodiments are performed, for example, the method steps S100 to S300 in fig. 1, the method steps S110 to S311 in fig. 3, the method steps S120 to S312 in fig. 4, and the like described above are performed.
The above described apparatus embodiments are merely illustrative, wherein the units illustrated as separate components may or may not be physically separate, i.e. may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
The embodiment of the invention also provides a vehicle, which comprises the vehicle controller of the embodiment. The vehicle may be a private car such as a sedan, SUV, MPV, or a pick-up card. The vehicle may also be an operator vehicle such as a minibus, bus, minivan or large trailer, etc. The vehicle can be an oil vehicle or a new energy vehicle. When the vehicle is a new energy vehicle, the vehicle can be a hybrid vehicle or a pure electric vehicle.
The vehicle adopts the vehicle controller to execute the rear wheel steering working mode switching control method, so that reasonable transition between working modes under different driving working conditions can be realized, unstable rear wheel steering working caused by frequent switching between different working modes is avoided, and therefore, the vehicle operability is reduced and even the vehicle is in dangerous driving working conditions, and the vehicle steering stability is effectively improved.
Because the vehicle adopts all the technical schemes of the vehicle controller in the above embodiments, the vehicle controller at least has all the beneficial effects brought by the technical schemes in the above embodiments, and the description thereof is omitted.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the knowledge of one of ordinary skill in the art.
Claims (9)
1. The rear wheel steering working mode switching control method is characterized by being applied to a vehicle with a rear wheel steering system, wherein the working modes of the rear wheel steering system comprise a first working mode and a second working mode, the first working mode is that the steering of rear wheels and front wheels of the vehicle is opposite, and the second working mode is that the steering of the rear wheels and the front wheels of the vehicle is the same; the control method comprises the following steps:
acquiring a signal of the rear wheel steering system, and judging whether a switching condition of an operating mode is met according to the signal, wherein the signal comprises a current operating mode of the rear wheel steering system, an operating mode switching request and an operating state of a rear wheel steering actuator;
When the switching condition of the working mode is met, controlling to start mode switching timing, wherein the time starting point of accumulated timing of the mode switching timing is a moment point for determining that the switching condition of the working mode is met, and comparing the accumulated time with a preset time threshold in the accumulating process;
and when the mode switching timing accumulation exceeds the preset time threshold, switching the working mode of the rear wheel steering system into the first working mode or the second working mode.
2. The rear wheel steering operation mode switching control method according to claim 1, wherein the vehicle further has a vehicle stability control system, and the determining whether the operation mode switching condition is satisfied based on the signal includes:
when the vehicle stability control system intervenes in working and sends out a working mode switching request, and the last control period of rear wheel steering is the first working mode or the non-working state, judging that the switching condition of the working mode is met;
the switching the working mode of the rear wheel steering system to the first working mode or the second working mode includes:
and switching the working mode of the rear wheel steering system to the second working mode.
3. The rear wheel steering operation mode switching control method according to claim 1, wherein the vehicle further has an intelligent driving system, the determining whether the operation mode switching condition is satisfied according to the signal, further comprising:
When the intelligent driving system intervenes in working and sends out a working mode switching request, and the last control period of rear wheel steering is the second working mode or the non-working state, judging that the switching condition of the working mode is met;
the switching the working mode of the rear wheel steering system to the first working mode or the second working mode includes:
and switching the working mode of the rear wheel steering system to the first working mode.
4. The rear wheel steering operation mode switching control method according to claim 1, characterized in that the control method further comprises:
When the mode switching timing accumulation does not exceed the preset time threshold, repeatedly executing the judgment of whether the switching condition of the working mode is met according to the signal;
when the switching condition of the working mode is met, controlling to start mode switching timing, including:
and controlling the mode switching timing to increase a control period until the control period is accumulated to exceed the preset time threshold.
5. The rear wheel steering operation mode switching control method according to claim 1, characterized in that the control method further comprises:
And when the switching condition of the working mode is not met, controlling not to switch the working mode of the rear wheel steering system, and maintaining the current working state of the rear wheel steering actuator.
6. The rear wheel steering operation mode switching control method according to claim 1, characterized in that the control method further comprises:
And acquiring the driving condition of the vehicle, and determining the preset time threshold according to the driving condition.
7. The rear wheel steering operation mode switching control method according to claim 6, wherein the acquiring the driving condition of the vehicle, and determining the preset time threshold according to the driving condition, includes:
Acquiring a working mode switching request, a current vehicle speed, a current steering wheel rotation angle and a rotation angle speed of the rear wheel steering system;
And selecting the corresponding preset time threshold according to the working mode switching request, the current vehicle speed, the current steering wheel rotation angle and the rotation angle speed.
8. A vehicle controller, characterized by being applied to a vehicle having a rear-wheel steering system, the operating modes of the rear-wheel steering system including a first operating mode in which the steering of the rear wheels and the front wheels of the vehicle is opposite, and a second operating mode in which the steering of the rear wheels and the front wheels of the vehicle is the same; the vehicle controller includes:
the signal acquisition module is used for acquiring signals of the rear wheel steering system, wherein the signals comprise a current working mode of the rear wheel steering system, a working mode switching request and a working state of a rear wheel steering actuator;
The condition judging module is used for judging whether the switching condition of the working mode is met or not according to the signal, when the switching condition of the working mode is met, the mode switching timing is controlled to be started, the time starting point of the accumulated timing of the mode switching timing is the moment point of determining the switching condition of the working mode, and the accumulated time is compared with a preset time threshold in the accumulating process;
and the rear steering execution module is used for switching the working mode of the rear wheel steering system into the first working mode or the second working mode when the mode switching timing accumulation exceeds the preset time threshold.
9. A vehicle comprising the vehicle controller of claim 8.
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| CN111762263A (en) * | 2020-07-01 | 2020-10-13 | 中国第一汽车股份有限公司 | Vehicle steering control system |
| CN114179905A (en) * | 2021-12-29 | 2022-03-15 | 吉林大学 | Control method of dual-mode rear wheel active steering system |
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| KR20210044329A (en) * | 2019-10-14 | 2021-04-23 | 주식회사 만도 | Apparatus and Method for switching driving mode |
| CN114312832A (en) * | 2021-12-20 | 2022-04-12 | 浙江天尚元科技有限公司 | Intelligent drive-by-wire chassis vehicle driving system based on mode switching and control method thereof |
| CN117584940A (en) * | 2023-11-22 | 2024-02-23 | 吉林大学 | Four-wheel steering mode dynamic switching control system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111762263A (en) * | 2020-07-01 | 2020-10-13 | 中国第一汽车股份有限公司 | Vehicle steering control system |
| CN114179905A (en) * | 2021-12-29 | 2022-03-15 | 吉林大学 | Control method of dual-mode rear wheel active steering system |
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