CN114919643B

CN114919643B - Active steering system, active steering control method and vehicle control device

Info

Publication number: CN114919643B
Application number: CN202210681599.4A
Authority: CN
Inventors: 施国标; 王帅; 宋铭昊; 刘廷阳; 乔鹏飞; 郭琮
Original assignee: Beijing Institute of Technology BIT
Current assignee: Beijing Institute of Technology BIT
Priority date: 2022-06-16
Filing date: 2022-06-16
Publication date: 2023-03-07
Anticipated expiration: 2042-06-16
Also published as: CN114919643A

Abstract

The invention relates to the technical field of automobile engineering, in particular to an active steering system, an active steering control method and a vehicle control device. The control device is used for controlling the vehicle to select a current steering mode, when the current steering mode is selected to be an automatic driving steering mode, road condition information and vehicle state information are obtained, ideal rotation angle calculation is carried out according to the obtained information, an ideal torque is obtained, then the control device controls the electric power assisting device to output the ideal torque to the torque transmission mechanism, the hydraulic power steering device carries out hydraulic power assisting on the vehicle tire according to the torque transmitted by the torque transmission mechanism, and active steering on the vehicle tire is further achieved.

Description

Active steering system, active steering control method and vehicle control device

Technical Field

The invention relates to the technical field of automobile engineering, in particular to an active steering system, an active steering control method and a vehicle control device.

Background

The steering system is a mechanism for maintaining or changing the running direction of the vehicle according to the intention of a driver on the vehicle, controls the transverse motion state of the whole vehicle, and influences the operation stability, the active safety and the comfort of the driver of the vehicle.

At present, the electric power steering technology is widely applied to passenger vehicles, the driving comfort and the steering maneuverability of the commercial vehicle with a large front axle load are much behind those of the passenger vehicle, and the conventional Hydraulic Power System (HPS) is still adopted for steering at present because the commercial vehicle is difficult to realize the electromotion of a steering system, and the conventional HPS has no active steering function, so that the contradiction exists between the portability and the stability of the steering, and the aligning performance is generally poor.

Disclosure of Invention

The invention provides an active steering system, an active steering control method and a vehicle control device, which aim to solve the problem that the conventional commercial vehicle cannot realize an active steering function.

According to a first aspect, an embodiment provides an active steering system comprising: the power steering system comprises a torque corner sensor, an electric power assisting device, a hydraulic power steering gear and a control device;

the torque and corner sensor is used for detecting the torque and the corner of the torque transmission mechanism; the torque transmission mechanism is used for transmitting torque to the hydraulic power steering gear;

the electric power assisting device is used for outputting torque to the torque transmission mechanism;

the hydraulic power-assisted steering device is used for performing hydraulic power-assisted steering according to the torque transmitted by the torque transmission mechanism;

the control device is used for:

determining a current steering mode;

when the current steering mode is the automatic driving steering mode, acquiring road condition information and vehicle state information;

and calculating an ideal rotation angle according to the road condition information and the vehicle state information, obtaining an ideal torque according to the calculated ideal rotation angle, and controlling the electric power assisting device to output the ideal torque to the torque transmission mechanism.

In one possible implementation, the control device is further configured to:

when the current steering mode is the power-assisted steering mode, acquiring the torque and the steering angle of the torque transmission mechanism detected by the torque and steering angle sensor; the torque and the steering angle of the torque transmitting mechanism are generated by a driver applying a steering torque to the torque transmitting mechanism;

and controlling the electric power assisting device to output motor power assisting moment to the moment transmission mechanism according to the torque and the rotation angle detected by the torque and rotation angle sensor.

In one possible implementation, the control device is further configured to:

when the current steering mode is the auxiliary driving steering mode, acquiring road condition information, vehicle state information and torque and steering angles detected by the torque and steering angle sensor;

predicting the running track of the vehicle according to the road condition information, the vehicle state information and the rotation information detected by the torque and rotation angle sensor to obtain a predicted offset distance;

obtaining an auxiliary torque according to the predicted offset distance and the input torque of the driver;

and controlling the electric power assisting device to output the superposed torque of the auxiliary torque and the power assisting torque to the torque transmission mechanism.

In one possible implementation, the control device obtains an assist torque based on the predicted offset distance and a driver input torque, and includes:

generating an expected auxiliary steering superposition torque according to the predicted offset distance;

fuzzy set calculation is carried out on the predicted offset distance and the input torque of the driver by adopting fuzzy logic control to obtain an auxiliary power-assisted judgment factor;

performing cooperative control on the expected auxiliary steering superposition torque through the auxiliary power judgment factor to obtain the auxiliary torque;

the calculation formula of the auxiliary torque is as follows:

T _lka ＝(1-k _j )*T _dp ；

in the formula, T _lka To assist torque, k _j To assist the power-assisted decision factor, T _dp Superimposing forces for desired assisted steeringMoment;

offset distance l to the prediction by a fuzzy logic control system _pd The analysis was carried out with a basic discourse field of [ -2,2]Inputting a torque T to the driver _d The analysis was carried out with a basic domain of discourse of [ -10, 10]Obtaining the auxiliary power judgment factor k _j Has a basic discourse of [0,1]]；

Input predicted offset distance l _pd And said driver input torque T _d Subset of fuzzy variables of (1): the predicted offset distance l _pd And said driver input torque T _d The fuzzy variable subsets of (1) all take 7 states of negative large, negative middle, negative small, zero, positive small, middle and positive large, and are marked as { NB, NM, NS, ZO, PS, PM, PB };

outputting the auxiliary power-assisted judgment factor k _j Fuzzy subset of (1): the auxiliary power-assisted judgment factor k _j The fuzzy subset of (1) takes zero, small, medium, large and maximum 5 states, and is marked as { ZO, PS, PM, PB, MB };

in the fuzzy logic control system rule, a first threshold value | T for representing the moment of a driver during emergency steering is designed _dz1 | =8Nm; designing a second threshold value | T characterizing the driver steering torque for non-interfering driving behaviour _dz2 ∣＝2Nm；

The fuzzy logic control system adopts the following principle:

when the driver inputs torque | T _d | is greater than the first threshold value, the driver inputs a torque T _d Is set to be in an emergency steering state and assists the power-assisted judgment factor k _j Is at a maximum;

when the driver inputs torque T _d In the case of medium or small, if the driver inputs the torque T _d And a predicted offset distance of l _pd If the direction is opposite, the operation is wrong, and the auxiliary power-assisted judgment factor k is used for judging the auxiliary power-assisted operation _j Is zero;

when the driver inputs torque T _d In the case of medium or small, if the driver inputs the torque T _d And a predicted offset distance of l _pd If the directions are the same, the operation is normal, and the auxiliary power judgment factor k _j Large, auxiliary assistance judgment reasonSub k _j Offset distance l is predicted with _pd Is increased and decreased;

when the driver inputs torque | T _d When | is less than the second threshold value, determining the driver input torque T _d Takes the fuzzy subset of zero and assists the assistance judgment factor k _j Is zero.

In one possible implementation example, the electric power assisting device comprises a double-winding type motor, a synchronous belt transmission mechanism and a double-winding steering electronic control module;

the double-winding steering electric control module is respectively and electrically connected with the double-winding motor and the torque angle sensor; the synchronous belt transmission mechanism is arranged on an output shaft of the double-winding motor and is connected with the torque transmission mechanism; the double-winding steering electric control module controls the double-winding motor to rotate, and the double-winding motor outputs motor torque to the torque transmission mechanism through the synchronous belt transmission mechanism.

In one possible implementation, the dual-winding steering electronic control module comprises a control unit, a power distribution unit, a fault diagnosis unit and a fault tolerance unit;

the control unit is used for receiving a control instruction sent by the control device and generating corresponding current information according to the control instruction;

the power distribution unit is used for distributing power to the double-winding motor according to the current information so as to enable the electric power assisting device to output torque corresponding to the control command;

the fault diagnosis unit is electrically connected with the double-winding motor and used for judging the availability of each set of winding in the double-winding motor so as to obtain availability information and sending the availability information of each set of winding to the fault-tolerant unit;

and the fault-tolerant unit is used for reconstructing faults of the double-winding motor according to the current information and the availability information of each set of windings.

In one possible implementation, the hydraulic power steering includes a cylinder, a hydraulic pump, a rotary valve, and a recirculating ball steering;

the rotary valve is connected with the torque transmission mechanism, the torque transmitted by the torque transmission mechanism controls the opening of the rotary valve, and the hydraulic pump inputs hydraulic oil in the oil cylinder into the circulating ball type steering gear through the rotary valve so as to provide hydraulic assistance for the circulating ball type steering gear, so that the steering of wheels is realized.

In one possible implementation, the control device determines a current steering mode, including:

receiving an automatic driving instruction, and determining that the current steering mode is the automatic driving steering mode based on the automatic driving instruction; or,

receiving an auxiliary driving instruction, and determining that the current steering mode is an auxiliary driving steering mode based on the auxiliary driving instruction; or,

when the current steering mode is not the automatic driving steering mode and the auxiliary driving steering mode, determining that the current steering mode is the power steering mode.

According to a second aspect, an embodiment provides an active steering control method, comprising:

determining a current steering mode;

calculating an ideal rotation angle according to the road condition information and the vehicle state information, obtaining an ideal torque according to the calculated ideal rotation angle, and controlling the electric power assisting device to output the ideal torque to the torque transmission mechanism;

controlling the torque transmission mechanism to transmit the ideal torque to a hydraulic power steering gear;

the hydraulic power steering gear performs hydraulic power steering according to the torque transmitted by the torque transmission mechanism, so that active steering of wheels is realized.

According to a third aspect, an embodiment provides a control apparatus of a vehicle including a torque angle sensor, an electric power assist apparatus, a hydraulic power steering, and a control apparatus, the control apparatus including:

the acquisition module is used for acquiring one or more of road condition information, driver action information, vehicle state information and torque and rotation angle detected by the torque and rotation angle sensor;

the selecting module is used for selecting the current steering mode;

and the control module is used for generating the steering torque required by the steering mode selected by the selection module according to the information acquired by the acquisition module so as to control the electric power assisting device to output the steering torque to the torque transmission mechanism.

According to the active steering system of the embodiment, the control device controls the vehicle to select the current steering mode, when the current steering mode is selected to be the automatic driving steering mode, road condition information and vehicle state information are obtained, ideal rotation angle calculation is carried out according to the obtained information, an ideal torque is obtained, then the control device controls the electric power assisting device to output the ideal torque to the torque transmission mechanism, and the hydraulic steering device carries out hydraulic power assisting on the vehicle tire according to the torque transmitted by the torque transmission mechanism, so that active steering on the vehicle tire is achieved.

Drawings

FIG. 1 is a schematic structural diagram of an active steering system provided in the present invention;

FIG. 2 is a front view of the electric assist apparatus provided by the present invention;

FIG. 3 is a block diagram of the integrated control of the active steering system provided by the present invention;

FIG. 4 is a steering control block diagram of the active steering system provided by the present invention;

FIG. 5 is a fuzzy logic controlled three-dimensional output result in a steering mode for assisting driving provided by the present invention;

FIG. 6 is a graph of driver input torque input, output membership function and membership relationship in an assisted steering mode provided by the present invention;

FIG. 7 is a graph of predicted offset distance input, output membership functions and membership relationships in an assisted driving steering mode according to the present invention;

FIG. 8 is a graph of the membership function and membership relationship for input and output of the assist power determination factor in the assisted steering mode;

fig. 9 is a flowchart of an active steering control method according to the present invention.

Reference numerals: 100. a torque transfer mechanism; 101. a torque rotation angle sensor; 200. an electric booster; 201. a double-winding steering electric control module; 202. a double winding type motor; 203. a synchronous belt transmission mechanism; 204. a connector assembly; 300. a hydraulic power steering gear; 301. rotating the valve; 302. a recirculating ball diverter; 303. a hydraulic pump; 304. an oil cylinder; 400. a control device; 500. and (4) a wheel.

Detailed Description

The present invention will be described in further detail with reference to the following detailed description and accompanying drawings. Wherein like elements in different embodiments are numbered with like associated elements. In the following description, numerous details are set forth in order to provide a better understanding of the present application. However, those skilled in the art will readily recognize that some of the features may be omitted or replaced with other elements, materials, methods in different instances. In some instances, certain operations related to the present application have not been shown or described in this specification in order not to obscure the core of the present application with unnecessary detail, and it is not necessary for those skilled in the art to describe these operations in detail, so that they may be fully understood from the description in the specification and the general knowledge in the art.

Furthermore, the features, operations, or characteristics described in the specification may be combined in any suitable manner to form various embodiments. Also, the various steps or actions in the method descriptions may be transposed or transposed in order, as will be apparent to one of ordinary skill in the art. Thus, the various sequences in the specification and drawings are for the purpose of clearly describing certain embodiments only and are not intended to imply a required sequence unless otherwise indicated where a certain sequence must be followed.

The ordinal numbers used herein for the components, such as "first," "second," etc., are used merely to distinguish between the objects described, and do not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings).

At present, the lane departure problem seriously threatens the personal safety of passengers, and particularly for a driver of a commercial vehicle, the situation of center driving such as driving fatigue and the like is very easy to occur under a single working condition, so that the vehicle deviates from the current lane or leaves the lane to cause traffic accidents. For this reason, the vehicle needs to prevent lane departure through active steering control. In order to solve the problems, the scheme provides an active steering system, an active steering control method and a vehicle control device so as to realize active steering of a vehicle.

Example 1

As shown in fig. 1, an active steering system according to an embodiment of the present invention includes: a torque angle sensor 101, an electric power steering apparatus 200, a hydraulic power steering 300, and a control apparatus 400.

As shown in fig. 1, the control device 400 includes an intelligent driving controller, which can determine a steering angle torque demand of the electric power assist device 200 by automatic or assisted driving, wherein a lane keeping function is mainly included in an assisted driving steering mode described below, and a decision at an upper layer of the assisted driving steering mode includes LKA (lane keeping) module path planning information.

The torque rotation angle sensor 101 is used to detect the torque and rotation angle of the torque transmission mechanism 100; the torque transmitting mechanism 100 is used to transmit torque to the hydraulic power steering gear.

In practical applications, the torque transmission mechanism 100 includes a steering wheel and a steering column, the torque angle sensor 101 is mounted on the steering column, the torque applied to the steering wheel by the driver can be transmitted to the hydraulic power steering device 300 through the steering column, and the torque and the angle of rotation of the steering wheel caused by the torque applied by the driver can be detected by the torque angle sensor 101.

The electric booster 200 is used to output torque to the torque transmission mechanism 100. The torque rotation angle sensor 101 is connected with the electric power steering device 200 through a hard wire, the torque rotation angle sensor 101 transmits information of detected torque and rotation angle to the electric power steering device 200 in the form of electric signals, the electric power steering device 200 converts the signals into current signals to control the electric power steering device 200 to generate torque, and the electric power steering device 200 is connected with the torque transmission mechanism 100, so that the electric power steering device 200 transmits the generated torque to the torque transmission mechanism 100, and the torque is transmitted to the hydraulic power steering device 300 through the torque transmission mechanism 100.

Specifically, referring to fig. 2, the electric power assisting device 200 includes a double-winding motor 202, a synchronous belt transmission mechanism 203, and a double-winding steering electric control module 201; the double-winding steering electronic control module 201 is electrically connected with the double-winding motor 202 and the torque angle sensor 101 respectively (wherein, the double-winding steering electronic control module 201 is connected with the torque angle sensor 101 through a CAN bus); the synchronous belt transmission mechanism 203 is arranged on the output shaft of the double-winding motor 202 and is connected with the torque transmission mechanism 100; the double-winding steering electronic control module 201 controls the double-winding motor 202 to rotate, and the double-winding motor 202 outputs motor assistance torque to the torque transmission mechanism 100 through the synchronous belt transmission mechanism 203.

As shown in fig. 1, the dual-winding steering electronic control module 201 includes a first controller ECU1 and a second controller ECU2, which are integrally disposed, the first controller ECU1 is connected to a first winding M1 of a dual-winding motor 202, the second controller ECU2 is connected to a second winding M2 of the dual-winding motor 202, and further, the first controller ECU1 and the second controller ECU2 are respectively connected to a torque angle sensor 101 through a connector 204, the torque angle sensor 101 has four independent torque signals and four independent angle signals, wherein two torque signals are hard-wired to the first controller ECU1, the other two torque signals are hard-wired to the second controller ECU2, the angle signals are hard-wired to the first controller ECU1, and the other two angle signals are hard-wired to the second controller ECU 2; meanwhile, the first controller ECU1 and the second controller ECU2 are also respectively connected with a power supply and a finished vehicle signal, so as to facilitate power supply and communication of the dual-winding steering electronic control module 201. The synchronous belt transmission mechanism 203 includes a driving synchronous pulley and a driven synchronous pulley, the driving synchronous pulley is installed on an output shaft of the double-winding motor 202, the driven synchronous pulley is installed on the steering column, the driving synchronous pulley drives the driven synchronous pulley to transmit through a synchronous belt, and an output torque of the double-winding motor 202 is transmitted to the steering column. Because the low friction advantage of belt drive is convenient for accurate control steering torque, adopt synchronous belt drive mechanism 203 in this scheme to transmit the moment of double-wound formula motor 202 transmission to steering column.

The hydraulic power steering apparatus 300 is used to perform hydraulic power steering in accordance with torque transmitted by the torque transmission mechanism 100.

Referring to fig. 1, the hydraulic power steering apparatus 300 includes a cylinder 304, a hydraulic pump 303, a rotary valve 301, and a recirculating ball steering apparatus 302; the rotary valve 301 is connected with the torque transmission mechanism 100, the torque transmitted by the torque transmission mechanism 100 controls the opening degree of the rotary valve 301, hydraulic oil in an oil cylinder 304 is input into the recirculating ball type steering gear 302 through the rotary valve 301 by a hydraulic pump 303, and then hydraulic assistance is provided for the recirculating ball type steering gear 302, so that the steering of the wheels 500 is realized. Specifically, the steering column is connected with a rotary valve 301 through an intermediate shaft, torque output by a double-winding motor 202 and torque output by a driver act on the steering column together, then torque applied to the steering column is twisted through the intermediate shaft to enable a torsion bar in the rotary valve 301 to be twisted, hydraulic oil in an oil cylinder 304 is input into a recirculating ball type steering gear 302 through the rotary valve 301 by a hydraulic pump 303, the rotating angle of the torsion bar and the flow of an oil inlet determine the magnitude of hydraulic power assistance, wherein the flow of the oil inlet is determined by the rotating speed of the hydraulic pump 303, and the recirculating ball type steering gear 302 acts on wheels 500 through a steering rod system to enable the wheels 500 to overcome steering resistance with a road surface, so that vehicle steering is realized.

Referring to fig. 3, the control device 400 is configured to: the current steering mode is determined.

Referring to fig. 3 and 4, the control device 400 includes an intelligent driving controller capable of determining current steering modes, specifically, an automatic driving steering mode, an auxiliary driving steering mode, and an assisted power steering mode. When a driver starts an automatic driving mode, the intelligent driving controller receives an automatic driving instruction, and determines that the current steering mode is the automatic driving steering mode based on the automatic driving instruction; when a driver starts an auxiliary driving steering mode, the intelligent driving controller receives an auxiliary driving instruction and determines that the current steering mode is the auxiliary driving steering mode based on the auxiliary driving instruction; when the driver is not initiating the autonomous driving steering mode and the assisted driving steering mode, the vehicle uses the basic steering mode, i.e., the power steering mode.

When the current steering mode is the automatic driving steering mode, acquiring road condition information and vehicle state information; and calculating an ideal rotation angle according to the road condition information and the vehicle state information, obtaining an ideal torque according to the calculated ideal rotation angle, and controlling the electric power assisting device 200 to output the ideal torque to the torque transmission mechanism 100.

The intelligent driving controller calculates an ideal steering wheel corner according to vehicle state information and road condition information by acquiring the vehicle state information and the road condition information, wherein the vehicle state information comprises a vehicle speed, a yaw angle, a lateral shift offset, a torque value of a steering wheel and a corner of the steering wheel, the vehicle state information is respectively obtained by detecting corresponding sensors, the road condition information comprises lane lines and road condition information, and the road condition information is acquired by a camera. Specifically, a three-closed-loop control strategy of the steering wheel angle is adopted, and the difference between the target steering wheel angle and the actual steering wheel angle is obtained through a position controller to obtain the target steering wheel rotating speed omega _sw '; the motor rotation speed omega is further obtained through the differentiation of the motor position obtained by the motor position sensor _m By dividing by the synchronous belt drive ratio i _m Obtaining a more accurate rotating speed value of the steering wheel, and obtaining a target current I under the condition of automatic steering by a speed controller according to the difference between the target rotating speed of the steering wheel and the actual rotating speed of the steering wheel _cmd The target current is sent to the dual-winding steering electronic control module 201, the dual-winding steering electronic control module 201 controls the dual-winding motor 202 to output a torque corresponding to the target current, i.e., an ideal torque to the torque transmission mechanism 100, the torque transmission mechanism 100 transmits the ideal torque to the hydraulic power steering 300, and then the vehicle is controlledAnd (5) steering the vehicle.

In addition, as the further optimization of this embodiment, when installing bifilar motor 202 in this scheme, with the axis direction of bifilar motor 202 output shaft with the axis direction parallel arrangement of steering column to commercial car arranges, saves driver's shank space, in addition, because space restriction, the drive ratio that the hold-in range can provide is limited, can match among the electric hydraulic steering system just less characteristics to electronic helping hand moment of torsion demand.

When the current steering mode is the power steering mode, acquiring the torque and the steering angle of the torque transmission mechanism 100 detected by a torque steering angle sensor 101; the torque and the steering angle of the torque transmitting mechanism 100 are generated by the driver applying a steering torque to the torque transmitting mechanism 100; the electric booster 200 is controlled to output the motor assist torque to the torque transmission mechanism 100 based on the torque and the rotational angle detected by the torque rotational angle sensor 101.

The dual winding steering electronic control module 201 recognizes the driver's steering intention, specifically, the steering torque applied by the driver (i.e., the driver input torque T) through the torque angle sensor 101 _d ) The current of the double-winding motor 202 is controlled through a power-assisted characteristic curve calibrated in the double-winding steering electronic control module 201, the steering power-assisted target current is obtained through various compensations such as inertia compensation, damping compensation, friction compensation and active return correction, and the double-winding steering electronic control module 201 controls the power-assisted double-winding motor 202 to generate the motor power-assisted torque T _a Motor assisting torque T _a The oil in the oil cylinder 304 is controlled by the hydraulic pump 303 to flow into the circulating ball type steering gear 302 through an opening of the rotary valve 301 to generate hydraulic power assistance, so that the steering rod system outputs tension, and finally, wheels 500 rotate, thereby realizing power-assisted steering.

When the current steering mode is the auxiliary driving steering mode, acquiring road condition information, vehicle state information and torque and steering angle detected by a torque steering angle sensor 101; predicting the vehicle running track according to the road condition information, the vehicle state information and the rotation information detected by the torque corner sensor 101 to obtain a predicted offset distance; obtaining an auxiliary torque according to the predicted offset distance and the input torque of the driver; the electric booster 200 is controlled to output a superimposed torque of the assist torque and the assist torque to the torque transmission mechanism 100.

The intelligent driving controller combines the camera, the sensors corresponding to the acquired vehicle state information and the vehicle dynamic model to predict the vehicle track, and the deviation between the actual vehicle running track and the predicted track is recorded as a predicted offset distance l _pd Generating an expected auxiliary steering superimposed torque T from the predicted offset distance _dp Further, in order to balance the driving assistance control system and the driver control authority, the offset distance l is predicted _pd And the driver input torque T _d Fuzzy set calculation is carried out by adopting fuzzy logic control to obtain an auxiliary power-assisted judgment factor k _j Then judging the factor k by auxiliary power assistance _j Superimposing a torque T on the intended auxiliary steering _dp And carrying out cooperative control to obtain the auxiliary torque. The assistance torque is determined by an auxiliary assistance judgment factor k _j The motor assist torque output by the dual winding motor 202 in the intervening power steering mode.

Specifically, referring to FIGS. 5-8, the offset distance l is predicted by using a fuzzy logic control system _pd The analysis was carried out with a basic discourse field of [ -2,2]Inputting a torque T to the driver _d The analysis was performed with a basic discourse field of [ -10, 10]Obtaining an auxiliary power judgment factor k _j Has a basic discourse field of [0,1]. Wherein a subset of the fuzzy variables (i.e., the prediction offset distance l) _pd And driver input torque T _d ) The states of negative big, negative middle, negative small, zero, positive small, positive middle and positive big are all taken and marked as { NB, NM, NS, ZO, PS, PM, PB }, and an auxiliary power judgment factor k is obtained _j The fuzzy subset of (1) takes zero, small, medium, large, and maximum 5 states, and is denoted as { ZO, PS, PM, PB, MB }.

In general, the auxiliary driving is applied to the high-speed driving state of the vehicle, and generally the auxiliary driving is more than 40km/h and even reaches 60km/h for commercial vehicles, and the steering stability is improved in the momentAnd the steering torque under the conventional power assistance is also relatively large. In the rules of a fuzzy logic control system, a first threshold value | T is designed which characterizes the driver's torque during an emergency steering _dz1 | =8Nm; the commercial vehicle has a certain torque due to pipe column friction, inertia, even hand holding of a driver and the like, and a second threshold value | T for representing the steering torque of the driver in non-intervention driving behaviors is designed _dz2 | =2Nm. Further, the fuzzy logic control system rules satisfy the following principles:

(1) When the driver inputs torque |. T _d | is greater than the first threshold value, when the driver inputs a torque T _d Is set to be in an emergency steering state and assists the power-assisted judgment factor k _j Should be the largest.

(2) When the driver inputs torque T _d In the case of medium or small, if the driver inputs torque T _d And the predicted offset distance l _pd The direction is opposite, and the auxiliary power judgment factor k is explained as misoperation _j Should be zero.

(3) When the driver inputs torque T _d In the case of medium or small, the judgment is made according to the structure, if the distance l is equal to the predicted offset distance _pd The direction is the same, the normal operation is described, and the auxiliary power judgment factor k _j Should be large, assist the determination factor k _j Should be offset by the predicted offset distance l _pd Is increased and decreased.

(4) When the driver inputs torque |. T _d When | is less than the second threshold value, determining the driver input torque T _d The fuzzy subset of (a) is taken as zero, and the auxiliary power judgment factor k _j Should be zero.

According to the above rules, a fuzzy rule control table is established, as shown in the following table:

referring to fig. 6-8, the driver input torque T is determined _d The domain of discourse range of { -10, -8, -6, -4, -2,0,2,4,6,8, 10}, and determining the prediction offset distance l _pd Domain range of { -2-1.5, -1, -0.5,0,0.5,1,1.5,2}, and determining an auxiliary power judgment factor k _j Range of domains of {0,0.25,0.5,0.75,1}. The mode of combining a trapezoidal membership function and a triangular membership function is adopted as a membership function to obtain an auxiliary power-assisted judgment factor k _j After fuzzy derivation according to the fuzzy rule, the result is still a fuzzy vector which can not be directly used as a control quantity, so that the fuzzy quantity is required to be converted into a clear quantity actually used for control to compensate. In order to strictly ensure the safety range set by the threshold and exert the advantages set by the threshold, an average maximum membership method is adopted to perform fuzzy solution operation based on the maximum membership principle, and the average maximum membership principle is as follows:

there are m fuzzy subsets A on the domain of concept U ₁ ，A ₁ ，A ₂ ，…，A _m (i.e. m models) to form a standard model library, if any one X ₀ Is e.g. U, has i ₀ E.g. {1,2, \ 8230;, m }, such that A _i0 (X ₀ )＝V ^m _k＝1 A ₁ (X ₀ ) Then, consider X ₀ Relative membership to A _i0 (X ₀ ). If a plurality of points take the maximum membership value on the domain of the fuzzy set, the abscissa of the average value of the points is taken as the representative point of the fuzzy set, and the method is called as the average maximum membership method.

In the assisted steering mode, the electric booster 200 outputs the total torque T _ma (including the assisting torque and the assisting torque) as follows:

T _ma ＝k _j *T _a0 +T _lka ；

wherein, T _a0 Represents the motor assist torque, T, generated by the dual-winding motor 202 in a pure power steering mode _lka Indicating the assist torque applied to the assist driving steering mode.

And the expected assist steering superimposed torque T _dp Assistance torque T actually applied to the assisted driving steering mode _lka An auxiliary power-assisted judgment factor k needs to be considered _j Assisting moment T _lka Is represented as follows:

T _lka ＝(1-k _j )*T _dp ；

when the auxiliary power judgment factor k _j 1, the steering torque T to which the steering column is subjected _ca Expressed as: t is a unit of _ca ＝T _d +T _ma ＝T _d +T _a0 This corresponds to a simple power steering mode.

As an auxiliary power judgment factor k _j Steering torque T applied to the steering column at 0 _ca Expressed as: t is _ca ＝T _d +T _ma ＝T _d +T _dp This corresponds to a simple assisted steering mode.

For easy understanding, the auxiliary power judgment factor k is _j Can also be understood as a manual intervention factor, when k _j When the torque is 1, the total torque output by the electric power assisting device 200 is applied by the power steering strategy; when k is _j At 0, the total torque output by the electric booster 200 is applied by the assist torque in the assist drive steering mode, and there is no steering assist torque determined by manually turning the steering wheel.

Therefore, in the assisted steering mode, the steering column finally provides the steering torque T actually to the hydraulic power steering 300, neglecting the mechanical loss of the steering column _ca (i.e., the superimposed torque of the driver input torque, the output assist torque of the electric assist device 200, and the assist torque in the assist drive steering mode) is expressed as follows:

T _ca ＝T _d +T _ma ＝T _d +k _j *T _a0 +(1-k _j )*T _dp ；

the steering column finally actually provides the steering torque T to the hydraulic power steering 300 _ca So that the vehicle keeps the original running track and the vehicle is prevented from deviating.

Referring to fig. 3, the dual winding steering electronic control module 201 includes a control unit, a power distribution unit, a fault diagnosis unit, and a fault tolerance unit; the control unit is used for receiving a control instruction sent by the control device 400 and generating corresponding current information according to the control instruction; the power distribution unit is used for distributing power to the double-winding motor 202 according to the current information so that the electric power assisting device 200 outputs torque corresponding to the control instruction; the fault diagnosis unit is electrically connected with the double-winding motor 202 and is used for judging the availability of each set of windings in the double-winding motor 202 so as to obtain availability information and sending the availability information of each set of windings to the fault-tolerant unit; the fault tolerant unit is used for reconstructing faults of the double-winding motor 202 according to the current information and the availability information of each set of windings.

By adjusting the target current of two sets of windings of the double-winding motor 202, the output power of each set of windings is reasonably distributed by the power distribution unit, and in addition, a protector is designed for a current circuit after the power distribution of the power distribution unit, so that the damage of the motor or a controller caused by overcurrent is prevented; monitoring according to the running state information of two sets of windings of the double-winding motor 202, the conditions of sensors and the like, and judging the availability of the double-winding motor through a fault diagnosis unit; further, a fault tolerance unit (i.e., a fault tolerance strategy) is designed, the actual current of the winding of the dual-winding motor 202 and the target current limited by the protector and the availability of the dual-winding motor 202 are used, and when the system fails, the fault reconstruction of the system is performed through current compensation under the fault tolerance strategy of the fault tolerance unit.

When the system is normal, the respective corresponding redundancies of the two sets of windings of the double-winding motor 202 work simultaneously, and each set of winding outputs 50% of power; when a certain set of windings of the system has a fault, firstly, the set of windings diagnosed to have the fault is isolated from the system through the fault diagnosis function, and then, the fault signal is transmitted to the set of windings which work normally by utilizing the redundancy communication function, so that the control state of the normal set of windings is changed, the output power of the normal set of windings is increased, the output power of the normal set of windings is enough to cover the torque requirement when the double-winding type electrodes work together, the output power of the system is further ensured to be unchanged, fault-tolerant control is realized, and the safety reliability and the safety of the system are improved. Because the double winding type motor 202 has two sets of windings, the requirement of high safety of steering can be met, and particularly, the redundant function required by L3-level automatic driving can be met.

Example 2

As shown in fig. 9, the active steering control method provided in this embodiment includes the following steps:

step S100: the current steering mode is determined.

Specifically, the current steering mode includes an automatic driving steering mode, an assisted driving steering mode, and a power steering mode. When a driver starts an automatic driving mode, the intelligent driving controller receives an automatic driving instruction, and determines that the current steering mode is the automatic driving steering mode based on the automatic driving instruction; when a driver starts an auxiliary driving steering mode, the intelligent driving controller receives an auxiliary driving instruction, and determines that the current steering mode is the auxiliary driving steering mode based on the auxiliary driving instruction; when the driver is not initiating the autonomous driving steering mode and the assisted driving steering mode, the vehicle uses the basic steering mode, i.e., the power steering mode.

Step S200: and when the current steering mode is the automatic driving steering mode, acquiring road condition information and vehicle state information.

The vehicle state information comprises vehicle speed, yaw angle, lateral shift offset, torque value of a steering wheel and turning angle of the steering wheel, the vehicle state information is obtained through detection of corresponding sensors, the road condition information comprises lane lines and road condition information, and the road condition information is obtained through collection of a camera.

Step S300: and calculating an ideal rotation angle according to the road condition information and the vehicle state information, obtaining an ideal torque according to the calculated ideal rotation angle, and controlling the electric power assisting device 200 to output the ideal torque to the torque transmission mechanism 100.

Specifically, a three-closed-loop control strategy of the steering wheel angle is adopted, and the difference between the target steering wheel angle and the actual steering wheel angle is obtained through a position controller to obtain the target steering wheel rotating speed omega _sw '; the motor rotation speed omega is further obtained through the differentiation of the motor position obtained by the motor position sensor _m By dividing by the synchronous belt drive ratio i _m Obtaining a more accurate rotating speed value of the steering wheel, and obtaining a target current I under the condition of automatic steering by a speed controller according to the difference between the target rotating speed of the steering wheel and the actual rotating speed of the steering wheel _cmd The target current is sent to the dual-winding steering electronic control module 201, the dual-winding steering electronic control module 201 controls the dual-winding motor 202 to output a torque corresponding to the target current, i.e., an ideal torque to the steering column, and the steering column transmits the ideal torque to the hydraulic power steering 300.

Step S400: the control torque transmitting mechanism 100 transmits the desired torque to the hydraulic power steering 300.

Step S500: the hydraulic power steering apparatus 300 performs hydraulic power steering according to the torque transmitted from the torque transmission mechanism 100, thereby implementing active steering of the wheels 500.

Specifically, the steering column is connected with a rotary valve 301 through an intermediate shaft, ideal torque output by a double-winding motor 202 and torque output by a driver act on the steering column together, then torque applied to the steering column is twisted through the intermediate shaft, a torsion bar in the rotary valve 301 is twisted, hydraulic oil in an oil cylinder 304 is input into a recirculating ball type steering gear 302 through the rotary valve 301 by a hydraulic pump 303, the rotating angle of the torsion bar and the flow of an oil inlet determine the magnitude of hydraulic power assistance, wherein the flow of the oil inlet is determined by the rotating speed of the hydraulic pump 303, the recirculating ball type steering gear 302 acts on wheels 500 through a steering rod system, and the wheels 500 overcome steering resistance with a road surface to achieve vehicle steering.

Further, step S100: after determining the current steering mode, the method further comprises the following steps: when the current steering mode is the auxiliary driving steering mode, acquiring road condition information, vehicle state information and torque and steering angle detected by a torque and steering angle sensor 101; predicting the running track of the vehicle according to the road condition information, the vehicle state information and the rotation information detected by the torque and rotation angle sensor 101 to obtain a predicted offset distance; obtaining an auxiliary torque according to the predicted offset distance and the input torque of the driver; the electric booster 200 is controlled to output a superimposed torque of the assist torque and the assist torque to the torque transmission mechanism 100.

The intelligent driving controller is combined with the camera, the sensors corresponding to the acquired vehicle state information and the vehicle dynamics model to predict the vehicle track, and the deviation between the actual vehicle running track and the predicted track is recorded as a predicted offset distance l _pd Generating an expected auxiliary steering superimposed torque T from the predicted offset distance _dp Further, in order to balance the driving assistance control system and the driver control authority, the offset distance l is predicted _pd With driver input torque T _d Fuzzy set calculation is carried out by adopting fuzzy logic control to obtain an auxiliary power-assisted judgment factor k _j Then judging the factor k by auxiliary power assistance _j Adding torque T to the anticipated auxiliary steering _dp And carrying out cooperative control to obtain the auxiliary torque. The assistance torque is determined by an auxiliary assistance judgment factor k _j The motor assist torque output by the dual winding motor 202 in the intervening power steering mode.

In particular, the offset distance l is predicted by using a fuzzy logic control system _pd The analysis was carried out with a basic discourse field of [ -2,2]Inputting a torque T to the driver _d The analysis was performed with a basic discourse field of [ -10, 10]Obtaining an auxiliary power judgment factor k _j Has a basic discourse field of [0,1]. Wherein a subset of the fuzzy variables (i.e., the prediction offset distance l) _pd And driver input torque T _d ) The states of large negative, medium negative, small negative, zero, small positive, medium positive and large positive are all taken and marked as { NB, NM, NS, ZO, PS, PM and PB }, and an auxiliary power judgment factor k is obtained _j The fuzzy subset of (1) takes zero, small, medium, large, and maximum 5 states, and is denoted as { ZO, PS, PM, PB, MB }.

In general, when the assistant driving is applied to a vehicle in a high-speed driving state, the speed of the commercial vehicle is generally more than 40km/h, even 60km/h, and at this time, in order to improve the stability of vehicle speed steering, the steering torque under the conventional power assistance is also relatively large. In the rules of the fuzzy logic control system, a first threshold value | T is provided for characterizing the driver torque during an emergency steering _dz1 - =8Nm; the commercial vehicle has a certain torque due to pipe column friction, inertia, even hand holding of a driver and the like, and a second threshold value | T for representing the steering torque of the driver in non-intervention driving behaviors is designed _dz2 | =2Nm. Further, the fuzzy logic control system rules satisfy the following principles:

(1) When the driver inputs torque | T _d | is greater than the first threshold value, when the driver inputsInput torque T _d Is set to be in an emergency steering state and assists the power-assisted judgment factor k _j Should be maximized.

(2) When the driver inputs torque T _d In the case of medium or small, if the driver inputs torque T _d And a predicted offset distance of l _pd The direction is opposite, and the auxiliary power judgment factor k is explained as misoperation _j Should be zero.

(4) When the driver inputs torque |. T _d When | is less than the second threshold value, determining the driver input torque T _d The fuzzy subset of the auxiliary power assistance judgment factor k is zero _j Should be zero.

determining driver input torque T _d The domain of discourse range of { -10, -8, -6, -4, -2,0,2,4,6,8, 10}, and determining the prediction offset distance l _pd Determining an auxiliary power-assisted judgment factor k in a domain range { -2, -1.5, -1, -0.5,0,0.5,1,1.5,2}, and determining an auxiliary power-assisted judgment factor k _j Range of domains of {0,0.25,0.5,0.75,1}. The mode of combining a trapezoidal membership function and a triangular membership function is adopted as a membership function to obtain an auxiliary power-assisted judgment factor k _j The fuzzy vector (2) is still a fuzzy vector after fuzzy derivation according to the fuzzy rule, and the result cannot be directly used as a control quantity, so that the fuzzy vector is required to be subjected to fuzzy derivationThe quantities are converted to clear quantities that are actually used for control to compensate. In order to strictly ensure the safety range set by the threshold and exert the advantages set by the threshold, an average maximum membership method is adopted to perform fuzzy solution operation based on the maximum membership principle, and the average maximum membership principle is as follows:

there are m fuzzy subsets A on the set domain U ₁ ，A ₁ ，A ₂ ，…，A _m (i.e., m models) to form a standard model library, if any X ₀ E is e.g. U, has i ₀ E.g. {1,2, \ 8230;, m }, such that A _i0 (X ₀ )＝V ^m _k＝1 A ₁ (X ₀ ) Then X is considered to be ₀ Relative membership to A _i0 (X ₀ ). If a plurality of points on the domain of the fuzzy set take the maximum membership value, the abscissa of the mean value of the points is taken as the representative point of the fuzzy set, and the method is called as the average maximum membership method.

In the assisted steering mode, the electric booster 200 outputs the total torque T _ma (including the assist torque and the assist torque) as follows:

T _ma ＝k _j *T _a0 +T _lka ；

While the intended assist steering superimposed torque T _dp Assistance torque T actually applied to the assisted driving steering mode _lka An auxiliary power-assisted judgment factor k needs to be considered _j Auxiliary moment T _lka Is represented as follows:

T _lka ＝(1-k _j )*T _dp ；

as an auxiliary power judgment factor k _j 1, the steering torque T to which the steering column is subjected _ca Expressed as: t is a unit of _ca ＝T _d +T _ma ＝T _d +T _a0 This corresponds to a simple power steering mode.

When the auxiliary power judgment factor k _j Steering torque T applied to the steering column at 0 _ca Expressed as: t is a unit of _ca ＝T _d +T _ma ＝T _d +T _dp In this case, the steering mode is equivalent to a simple assist steering mode.

For easy understanding, the auxiliary power judgment factor k is _j Can also be understood as a manual intervention factor, when k _j When the torque is 1, the total torque output by the electric power assisting device 200 is applied by the power steering strategy; when k is _j At 0, the total torque output from the electric booster 200 is applied by the assist torque in the assist drive steering mode, and there is no steering assist torque determined by manually turning the steering wheel.

T _ca ＝T _d +T _ma ＝T _d +k _j *T _a0 +(1-k _j )*T _dp ；

Further, step S100: after determining the current steering mode, the method further comprises the following steps: when the current steering mode is the power steering mode, acquiring the torque and/or the steering angle of the torque transmission mechanism 100 detected by a torque steering angle sensor 101; the torque and/or rotational angle of torque-transmitting mechanism 100 is produced by the driver applying a steering torque to torque-transmitting mechanism 100; the electric booster 200 is controlled to output the motor assist torque to the torque transmission mechanism 100 based on the torque and/or the rotational angle detected by the torque rotational angle sensor 101.

The dual winding steering electronic control module 201 recognizes the driver's steering intention, specifically, the steering torque applied by the driver (i.e., the driver input torque T) through the torque angle sensor 101 _d ) Electric control die by double winding steeringThe power-assisted characteristic curve calibrated in the block 201 controls the current of the double-winding motor 202, the steering power-assisted target current is obtained through various compensations such as inertia compensation, damping compensation, friction compensation and active return correction, and the double-winding steering electronic control module 201 controls the power-assisted double-winding motor 202 to generate the motor power-assisted torque T _a Motor assisting torque T _a The oil in the oil cylinder 304 is controlled by the hydraulic pump 303 to flow into the circulating ball type steering gear 302 through an opening of the rotary valve 301 to generate hydraulic power assistance, so that the steering rod system outputs tension, and finally, wheels 500 rotate, thereby realizing power-assisted steering.

It should be noted that the active steering control method of the present embodiment is applied to the active steering system in embodiment 1, and all devices used in the operation process of the active steering control method of the present embodiment are the devices in embodiment 1, which is not described herein in detail.

Example 3

A control device for a vehicle according to the present embodiment includes a torque angle sensor 101, an electric booster 200, a hydraulic power steering 300, and a control device 400, and the control device 400 includes: the device comprises an acquisition module, a selection module and a control module. The acquisition module is used for acquiring one or more of road condition information, driver action information, vehicle state information, and torque and/or steering angle detected by the torque steering angle sensor 101.

Specifically, the acquisition module can acquire road condition information, driver action information, vehicle state information, and torque and steering angle detected by the torque steering angle sensor 101. The vehicle state information comprises vehicle speed, yaw angle, lateral shift offset, torque value of a steering wheel and turning angle of the steering wheel, the vehicle state information is obtained through detection of corresponding sensors respectively, the road condition information comprises lane lines and road condition information, the road condition information is obtained through collection of a camera, and driver action information, torque and turning angle can be obtained through detection of a torque turning angle sensor 101.

The selection module is used for selecting the current steering mode.

The control module is configured to generate a steering torque required by the steering mode selected by the selection module according to the information acquired by the acquisition module, so as to control the electric power assisting device 200 to output the steering torque to the torque transmitting mechanism 100. Wherein the control module is a steering controller.

Specifically, when the current steering mode is selected as the automatic driving steering mode, acquiring road condition information and vehicle state information; the control module calculates an ideal rotation angle according to the road condition information and the vehicle state information, obtains an ideal torque according to the calculated ideal rotation angle, and controls the electric power assisting device 200 to output the ideal torque to the torque transmission mechanism 100.

The acquisition module acquires vehicle state information and road condition information and transmits the information to the steering control module, the steering control module calculates an ideal steering wheel corner according to the vehicle state information and the road condition information, wherein the vehicle state information comprises a vehicle speed, a yaw angle, a lateral shift offset, a torque value of a steering wheel and a steering angle of the steering wheel, the vehicle state information is respectively obtained by detecting corresponding sensors, the road condition information comprises lane lines and road condition information, and the road condition information is acquired by a camera. Specifically, a three-closed-loop control strategy of steering wheel rotation angle is adopted, and the difference between the target steering wheel rotation angle and the actual steering wheel rotation angle is obtained through a position controller to obtain the target steering wheel rotation speed omega _sw '; the motor rotation speed omega is further obtained through the differentiation of the motor position obtained by the motor position sensor _m By dividing by the synchronous belt drive ratio i _m Obtaining a more accurate rotating speed value of the steering wheel, and obtaining a target current I under the condition of automatic steering by a speed controller according to the difference between the target rotating speed of the steering wheel and the actual rotating speed of the steering wheel _cmd The target current is sent to the dual-winding steering electronic control module 201, the dual-winding steering electronic control module 201 controls the dual-winding motor 202 to output a torque corresponding to the target current, that is, an ideal torque to the torque transmission mechanism 100, and the torque transmission mechanism 100 transmits the ideal torque to the hydraulic power steering 300, so as to control the steering of the vehicle.

When the current steering mode is selected as the power steering mode, acquiring the torque and/or the steering angle of the torque transmission mechanism 100 detected by a torque steering angle sensor 101; the torque and/or steering angle of torque-transmitting mechanism 100 is generated by the driver applying a steering torque to torque-transmitting mechanism 100; the steering controller controls the electric booster 200 to output the motor assist torque to the torque transmission mechanism 100 based on the torque and the steering angle detected by the torque steering angle sensor 101.

The dual-winding steering electronic control module 201 recognizes the driver's steering intention, specifically, the steering torque applied by the driver (i.e., the driver input torque T) through the torque angle sensor 101 _d ) The current of the double-winding motor 202 is controlled through a power-assisted characteristic curve calibrated in the double-winding steering electronic control module 201, the steering power-assisted target current is obtained through various compensations such as inertia compensation, damping compensation, friction compensation and active return correction, and the double-winding steering electronic control module 201 controls the power-assisted double-winding motor 202 to generate the motor power-assisted torque T _a Motor assisting torque T _a The oil is transmitted to a steering column through a synchronous belt transmission mechanism 203, the steering column transmits the oil to an intermediate shaft, the intermediate shaft acts on a rotary valve 301 torsion bar of the hydraulic power steering gear 300, the torsion bar is opened, the hydraulic pump 303 controls the oil in the oil cylinder 304 to flow into the circulating ball type steering gear 302 through an opening of the rotary valve 301 to generate hydraulic power, the steering rod system outputs tensile force, and finally wheels 500 rotate to realize power steering.

When the current steering mode is the auxiliary driving steering mode, acquiring road condition information, vehicle state information and torque and steering angle detected by a torque steering angle sensor 101; the steering controller predicts the vehicle running track according to the road condition information, the vehicle state information and the rotation information detected by the torque and rotation angle sensor 101 to obtain a predicted offset distance; obtaining an auxiliary torque according to the predicted offset distance and the input torque of the driver; the electric booster 200 is controlled to output a superimposed torque of the assist torque and the assist torque to the torque transmission mechanism 100.

Steering controller combines camera, each sensor that obtains vehicle state information and vehicle dynamics mould that correspondsPredicting the vehicle track, and recording the deviation between the actual vehicle running track and the predicted track as a predicted offset distance l _pd Generating an expected assist steering superimposed torque T from the predicted offset distance _dp Further, in order to balance the driving assistance control system and the driver control authority, the offset distance l is predicted _pd And the driver input torque T _d Fuzzy set calculation is carried out by adopting fuzzy logic control to obtain an auxiliary power-assisted judgment factor k _j Then judging the factor k by auxiliary power assistance _j Adding torque T to the anticipated auxiliary steering _dp And carrying out cooperative control to obtain the auxiliary torque. The assistance torque is determined by an auxiliary assistance judgment factor k _j The motor assist torque output by the dual winding motor 202 in the intervening power steering mode.

In particular, the offset distance l is predicted by using a fuzzy logic control system _pd The analysis was carried out with a basic domain of discourse of [ -2,2]Inputting a torque T to the driver _d The analysis was carried out with a basic domain of discourse of [ -10, 10]Obtaining an auxiliary power judgment factor k _j Has a basic discourse field of [0,1]. Wherein a subset of the fuzzy variables (i.e., the prediction offset distance l) _pd And driver input torque T _d ) The states of negative big, negative middle, negative small, zero, positive small, positive middle and positive big are all taken and marked as { NB, NM, NS, ZO, PS, PM, PB }, and an auxiliary power judgment factor k is obtained _j The fuzzy subset of (1) takes zero, small, medium, large and maximum 5 states, and is marked as { ZO, PS, PM, PB, MB }.

In general, when the assistant driving is applied to a vehicle in a high-speed driving state, the speed of the commercial vehicle is generally more than 40km/h, even 60km/h, and at this time, in order to improve the stability of vehicle speed steering, the steering torque under the conventional power assistance is also relatively large. In the rules of the fuzzy logic control system, a first threshold value | T is provided for characterizing the driver torque during an emergency steering _dz1 - =8Nm; the commercial vehicle has certain torque due to pipe column friction, inertia, even hand holding of a driver and other factors, and a second threshold value | T for representing the steering torque of the driver in non-intervention driving behaviors is designed _dz2 | =2Nm. Further, the fuzzy logic control system rule satisfies the following principle:

(1) When the driver inputs torque |. T _d | is greater than the first threshold value, when the driver inputs torque T _d Is set to be in an emergency steering state and assists the power-assisted judgment factor k _j Should be the largest.

(3) When the driver inputs torque T _d In the middle or small, the judgment is made according to the structure, if the distance is l from the predicted offset _pd The direction is the same, the normal operation is described, and the auxiliary power judgment factor k _j Should be large, assist the determination factor k _j Should be offset by the predicted offset distance l _pd Is increased and decreased.

(4) When the driver inputs torque |. T _d When | is less than the second threshold value, determining the driver input torque T _d Takes the fuzzy subset of zero and assists the assistance judgment factor k _j Should be zero.

determining driver input torque T _d The domain of discourse range of { -10, -8, -6, -4, -2,0,2,4,6,8, 10}, and determining the prediction offset distance l _pd Determining an auxiliary power-assisted judgment factor k according to the domain range { -2, -1.5, -1, -0.5,0,0.5,1,1.5,2}, and determining an auxiliary power-assisted judgment factor k _j Range of domains of {0,0.25,0.5,0.75,1}. The mode of combining a trapezoidal membership function and a triangular membership function is adopted as a membership function to obtain an auxiliary power assistance judgment factor k _j After the fuzzy vector is derived in a fuzzy manner according to the fuzzy rule, the result is still a fuzzy vector which cannot be directly used as a control quantity, so that the fuzzy quantity is required to be converted into a clear quantity actually used for control to be compensated. To be strictly ensuredThe safety range set by the threshold is proved, the advantages set by the threshold are exerted, the fuzzy operation is solved by adopting an average maximum membership method based on the maximum membership principle, and the average maximum membership principle is as follows:

there are m fuzzy subsets A on the set domain U ₁ ，A ₁ ，A ₂ ，…，A _m (i.e., m models) to form a standard model library, if any X ₀ E is e.g. U, has i ₀ E.g. {1,2, \ 8230;, m }, such that A _i0 (X ₀ )＝V ^m _k＝1 A ₁ (X ₀ ) Then, consider X ₀ Relative membership to A _i0 (X ₀ ). If a plurality of points take the maximum membership value on the domain of the fuzzy set, the abscissa of the average value of the points is taken as the representative point of the fuzzy set, and the method is called as the average maximum membership method.

In the assisted driving steering mode, the electric booster 200 outputs the total torque T _ma (including the assist torque and the assist torque) as follows:

T _ma ＝k _j *T _a0 +T _lka ；

While the intended assist steering superimposed torque T _dp Assistance torque T actually applied to the steering mode for assisted driving _lka The auxiliary power judgment factor k needs to be considered _j Auxiliary moment T _lka Is represented as follows:

T _lka ＝(1-k _j )*T _dp ；

as an auxiliary power judgment factor k _j 1, the steering torque T to which the steering column is subjected _ca Expressed as: t is _ca ＝T _d +T _ma ＝T _d +T _a0 This corresponds to a simple power steering mode.

When the auxiliary power judgment factor k _j Steering torque T applied to the steering column at 0 _ca Expressed as:T _ca ＝T _d +T _ma ＝T _d +T _dp in this case, the steering mode is equivalent to a simple assist steering mode.

For easy understanding, the auxiliary power judgment factor k is _j Can also be understood as a manual intervention factor when k _j When the torque is 1, the total torque output by the electric power assisting device 200 is applied by the power steering strategy; when k is _j At 0, the total torque output from the electric booster 200 is applied by the assist torque in the assist drive steering mode, and there is no steering assist torque determined by manually turning the steering wheel.

Therefore, in the assisted steering mode, the steering column finally provides the steering torque T actually to the hydraulic power steering 300, neglecting the mechanical loss of the steering column _ca (i.e., the superimposed torque of the driver input torque, the electric booster 200 output assist torque, and the assist torque in the assist steering mode) is expressed as follows:

T _ca ＝T _d +T _ma ＝T _d +k _j *T _a0 +(1-k _j )*T _dp ；

steering torque T that the steering column actually finally provides to the hydraulic power steering 300 _ca So that the vehicle keeps the original running track and the vehicle is prevented from deviating.

It should be noted that the vehicle control device of the present embodiment is applied to the active steering system of embodiment 1, and when the vehicle control device of the present embodiment is used, the vehicle control device of the present embodiment is used together with the other components (the torque angle sensor 101, the electric power steering apparatus 200, and the hydraulic power steering apparatus 300) described in embodiment 1, and redundant description of the present embodiment is omitted.

The present invention has been described in terms of specific examples, which are provided to aid understanding of the invention and are not intended to be limiting. Numerous simple deductions, modifications or substitutions may also be made by those skilled in the art in light of the present teachings.

Claims

1. An active steering system, comprising: the power steering system comprises a torque corner sensor, an electric power assisting device, a hydraulic power steering gear and a control device;

the control device is used for:

determining a current steering mode;

when the current steering mode is the auxiliary driving steering mode, acquiring road condition information, vehicle state information and torque and steering angle detected by the torque and steering angle sensor;

predicting the vehicle running track according to the road condition information, the vehicle state information and the rotation information detected by the torque corner sensor to obtain a predicted offset distance;

performing cooperative control on the expected auxiliary steering superposition torque through the auxiliary power judgment factor to obtain an auxiliary torque;

the electric power assisting device is controlled to output the superposed torque of the auxiliary torque and the power assisting torque to the torque transmission mechanism;

wherein, the formula of the auxiliary torque is as follows:

T _lka =（1-k _j ）*T _dp ；

in the formula, T _lka To assist torque, k _j To assist the power-assisted decision factor, T _dp Superimposing a torque for the desired assist steering;

the predicted offset distance lpd is analyzed by a fuzzy logic control system with a basic universe of discourse of [ -2,2]The driver input torque Td is analyzed with a basic domain of discourse of [ -10, 10 [ -10 [ ]]Obtaining the auxiliary power judgment factor k _j Has a basic discourse of [0,1]]；

outputting the auxiliary power-assisted judgment factor k _j Fuzzy subset of (1): the auxiliary power-assisted judgment factor k _j The fuzzy subset of (1) takes 5 states of zero, small, medium, large and maximum, and is marked as { ZO, PS, PM, PB, MB };

in the rules of the fuzzy logic control system, a first threshold value | T is designed which characterizes the driver torque during an emergency steering _dz1 - =8Nm; designing a second threshold value | T characterizing the driver steering torque for non-interfering driving behaviour _dz2 ∣=2Nm；

The fuzzy logic control system adopts the following principle:

when the driver inputs torque |. T _d | is greater than the first threshold value, the driver inputs a torque T _d Is set to be in an emergency steering state and assists the power-assisted judgment factor k _j Is at a maximum;

when the driver is drivingInput torque T _d In the case of medium or small, if the driver inputs the torque T _d And the predicted offset distance l _pd If the directions are the same, the operation is normal, and the auxiliary power judgment factor k _j Is large, assists the judgment factor k of the assisting force _j Offset distance l is predicted with _pd Is increased and decreased;

when the driver inputs torque |. T _d | determining the driver input torque T when less than a second threshold value _d Takes the fuzzy subset of zero and assists the assistance judgment factor k _j Is zero.

2. The active steering system of claim 1, wherein the control device is further configured to:

when the current steering mode is the power-assisted steering mode, acquiring the torque and the steering angle of the torque transmission mechanism detected by the torque steering angle sensor; the torque and the steering angle of the torque transmitting mechanism are generated by a driver applying a steering torque to the torque transmitting mechanism;

3. The active steering system of claim 1, wherein the electric power assist device comprises a dual-winding motor, a synchronous belt drive mechanism, a dual-winding steering electronic control module;

the double-winding steering electric control module is respectively and electrically connected with the double-winding motor and the torque angle sensor; the synchronous belt transmission mechanism is arranged on an output shaft of the double-winding motor and is connected with the torque transmission mechanism; the double-winding steering electric control module controls the double-winding motor to rotate, and the double-winding motor outputs motor torque assistance to the torque transmission mechanism through the synchronous belt transmission mechanism.

4. The active steering system of claim 3, wherein the dual winding steering electronic control module comprises a control unit, a power distribution unit, a fault diagnosis unit, and a fault tolerance unit;

5. The active steering system of claim 1, wherein the hydraulic power steering includes a ram, a hydraulic pump, a rotary valve, and a recirculating ball steering gear;

the rotary valve is connected with the torque transmission mechanism, the torque transmitted by the torque transmission mechanism controls the opening of the rotary valve, and the hydraulic pump inputs hydraulic oil in the oil cylinder into the recirculating ball type steering gear through the rotary valve so as to provide hydraulic assistance for the recirculating ball type steering gear, so that the steering of wheels is realized.

6. The active steering system of claim 1, wherein the control means determines a current steering mode comprising:

7. An active steering control method characterized by comprising:

determining a current steering mode;

the hydraulic power-assisted steering device performs hydraulic power-assisted steering according to the torque transmitted by the torque transmission mechanism, so as to realize active steering of wheels;

when the current steering mode is the auxiliary driving steering mode, acquiring road condition information, vehicle state information and torque and steering angle detected by a torque and steering angle sensor;

wherein, the formula of the auxiliary torque is as follows:

T _lka =（1-k _j ）*T _dp ；

analyzing the predicted offset distance lpd through a fuzzy logic control system, wherein the basic domain is [ -2,2], analyzing the input torque Td of the driver, wherein the basic domain is [ -10, 10], and obtaining the basic domain of the auxiliary power judgment factor kj as [0,1];

in the fuzzy logic control system rule, a first threshold value | T for representing the moment of a driver during emergency steering is designed _dz1 - =8Nm; designing a second threshold value | T characterizing the steering torque of the driver for non-intrusive driving behaviour _dz2 ∣=2Nm；

The fuzzy logic control system adopts the following principle:

when the driver inputs torque T _d In the case of medium or small, if the driver inputs the torque T _d And a predicted offset distance of l _pd If the direction is opposite, the operation is a misoperation, and the auxiliary power judgment factor k _j Is zero;

when the driver inputs torque T _d In the case of medium or small, if the driver inputs the torque T _d And the predicted offset distancel _pd If the directions are the same, the operation is normal, and the auxiliary power judgment factor k _j Is large, assists the judgment factor k of the assisting force _j Offset distance l is predicted with _pd Is increased and decreased;

when the driver inputs torque |. T _d When | is less than the second threshold value, determining the driver input torque T _d Takes the fuzzy subset of zero and assists the assistance judgment factor k _j Is zero.

8. A control device of a vehicle, characterized by comprising a torque angle sensor, an electric power steering device, a hydraulic power steering, and a control device, the control device comprising:

the selecting module is used for selecting the current steering mode;

the steering control module is used for generating the steering torque required by the steering mode selected by the selection module according to the information acquired by the acquisition module so as to control the electric power assisting device to output the steering torque to the torque transmission mechanism;

the steering control module is further used for acquiring road condition information, vehicle state information and torque and steering angle detected by the torque and steering angle sensor when the current steering mode selected by the selection module is an auxiliary driving steering mode;

controlling the electric power assisting device to output the superposed torque of the auxiliary torque and the power assisting torque to the torque transmission mechanism;

wherein, the formula of the auxiliary torque is as follows:

T _lka =（1-k _j ）*T _dp ；

in the formula, T _lka To assist torque, k _j To assist in determining the factor, T _dp Superimposing a torque for the desired assist steering;

analyzing the predicted offset distance lpd through a fuzzy logic control system, wherein the basic domain of the predicted offset distance lpd is [ -2,2], analyzing the driver input torque Td, and the basic domain of the driver input torque Td is [ -10, 10], so that the basic domain of the auxiliary power judgment factor kj is [0,1];

in the fuzzy logic control system rule, a first threshold value | T for representing the moment of a driver during emergency steering is designed _dz1 - =8Nm; designing a second threshold value | T characterizing the driver steering torque for non-interfering driving behaviour _dz2 ∣=2Nm；

The fuzzy logic control system adopts the following principle:

when the driver inputs torqueT _d In the case of medium or small, if the driver inputs the torque T _d And the predicted offset distance l _pd If the direction is opposite, the operation is wrong, and the auxiliary power-assisted judgment factor k is used for judging the auxiliary power-assisted operation _j Is zero;

when the driver inputs torque T _d In the case of medium or small, if the driver inputs the torque T _d And the predicted offset distance l _pd If the directions are the same, the operation is normal, and the auxiliary power judgment factor k _j Is large, assists the power-assisted judgment factor k _j Offset distance l is predicted with _pd Is increased and decreased;