Vehicle and steering control method, device and computer program product thereof

Abstract

The present invention provides a vehicle and a steering control method, device and computer program product thereof. The method comprises: obtaining state parameters and limiting parameters of the vehicle; determining a center of mass sideslip angle compensation value and a yaw angular velocity compensation value according to the state parameters and the limiting parameters; and controlling the vehicle steering according to the center of mass sideslip angle compensation value and the yaw angular velocity compensation value. The present invention fully considers the influence of the external environment on the vehicle steering by adding limiting parameters, avoids the disturbance of the compensation value caused by the real-time changing road friction force, and thus the calculated compensation value is more accurate and can adapt to complex driving conditions, thereby improving the stability, real-timeness and versatility of the vehicle steering in the wire control steering system.

Description

Technical Field

[0001] The present invention relates to the field of vehicle technology, and in particular to a vehicle and a steering control method, device and computer program product thereof. Background Art

[0002] In the related art, the ideal values ​​of the sideslip angle and the yaw rate are calculated through information parameters of the current condition of the vehicle, and the additional control value is determined according to the difference between the current sideslip angle and the yaw rate and the corresponding ideal values. The vehicle operation is controlled according to the additional control value. However, when the above method is used to calculate the ideal value, since the vehicle is on different road surfaces, the real-time change of the road friction force disturbs the ideal value, resulting in the calculated additional control value being unable to adapt to complex driving conditions. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0004] To this end, an object of the present invention is to propose a vehicle steering control method, which fully takes into account the influence of the external environment on the vehicle steering by adding a limiting parameter, avoids the disturbance of the compensation value caused by the real-time changing road friction, and thus the calculated compensation value is more accurate and can adapt to complex driving conditions, thereby improving the stability, real-time and versatility of the vehicle steering in the wire control steering system.

[0005] To this end, a second object of the present invention is to provide a steering control device for a vehicle.

[0006] To this end, a third object of the present invention is to provide a vehicle.

[0007] To this end, a fourth object of the present invention is to provide a computer-readable storage medium.

[0008] To this end, a fifth object of the present invention is to provide a computer program product.

[0009] In order to achieve the above-mentioned purpose, an embodiment of the first aspect of the present invention proposes a vehicle steering control method, the method comprising: obtaining state parameters and limiting parameters of the vehicle; determining a center of mass sideslip angle compensation value and a yaw angular velocity compensation value according to the state parameters and the limiting parameters; and controlling the vehicle steering according to the center of mass sideslip angle compensation value and the yaw angular velocity compensation value.

[0010] According to the steering control method of the vehicle in the embodiment of the present invention, by acquiring the state parameters and limiting parameters of the vehicle, the center of mass sideslip angle compensation value and the yaw angular velocity compensation value are jointly determined according to the state parameters and the limiting parameters, and the vehicle steering is controlled according to the center of mass sideslip angle compensation value and the yaw angular velocity compensation value. On the basis of the joint control of the center of mass sideslip angle and the yaw angular velocity used in the prior art, by adding the limiting parameters, the influence of the external environment on the vehicle steering is fully considered, and the disturbance of the compensation value caused by the real-time changing road friction force is avoided. The calculated compensation value is more accurate and can adapt to complex driving conditions, thereby improving the stability, real-time and versatility of the vehicle steering in the wire control steering system.

[0011] In some embodiments, determining a center of mass slip angle compensation value and a yaw rate compensation value according to the state parameters and the limiting parameters includes: determining a target center of mass slip angle and a target yaw rate according to the state parameters and the limiting parameters; determining an actual center of mass slip angle according to the state parameters; calculating an angular difference between the target center of mass slip angle and the actual center of mass slip angle, and calculating a center of mass slip angle compensation value according to the angular difference and vehicle control parameters; calculating an angular velocity difference between the target yaw rate and the actual yaw rate, and calculating the yaw rate compensation value according to the angular velocity difference and vehicle control parameters.

[0012] In some embodiments, the state parameters include a first state parameter, and determining the target yaw rate according to the state parameter and the limit parameter includes: determining a theoretical target yaw rate according to the first state parameter; determining a limited target yaw rate according to the first state parameter and the limit parameter; and taking the smaller value of the theoretical target yaw rate and the limited target yaw rate as the target yaw rate.

[0013] In some embodiments, the state parameter includes a second state parameter, and determining the target center of mass sideslip angle according to the state parameter and the limiting parameter includes: determining a theoretical target center of mass sideslip angle according to the second state parameter; determining a limit target center of mass sideslip angle according to the limiting parameter; and taking the smaller value between the theoretical target center of mass sideslip angle and the limit target center of mass sideslip angle as the target center of mass sideslip angle.

[0014] In some embodiments, when determining the theoretical target yaw rate according to the first state parameter, the first state parameter is substituted into the following formula to obtain the theoretical target yaw rate, including:

[0015] ,

[0016] in, is the theoretical target yaw rate, is the longitudinal velocity, is the turning radius, is the distance from the front axle to the center of mass of the vehicle, is the distance from the rear axle to the center of mass of the vehicle, is the mass of the vehicle, is the vehicle's front tire cornering stiffness, is the vehicle's rear tire cornering stiffness, is the sum of the distances from the front axle and the rear axle to the center of mass of the vehicle, is the vehicle speed, is the front wheel turning angle.

[0017] In some embodiments, when determining the limited target yaw rate according to the first state parameter and the limit parameter, the first state parameter and the limit parameter are substituted into the following formula to obtain the limited target yaw rate, including:

[0018] ,

[0019] in, is the limit target yaw rate, is the road adhesion coefficient, is the acceleration due to gravity, is the derivative of the longitudinal velocity.

[0020] In some embodiments, when determining the theoretical target center of mass sideslip angle according to the second state parameter, the second state parameter is substituted into the following formula to obtain the theoretical target center of mass sideslip angle, including:

[0021] ,

[0022] in, is the theoretical target center of mass sideslip angle, is the distance from the front axle to the center of mass, is the distance from the rear axle to the center of mass, is the mass of the vehicle, is the front tire cornering stiffness, is the rear tire cornering stiffness, is the vehicle speed, is the front wheel turning angle.

[0023] In some embodiments, when determining the limit target center of mass sideslip angle according to the limit parameter, the limit parameter is substituted into the following formula to obtain the limit target center of mass sideslip angle, including:

[0024] ,

[0025] in, is the limit target center of mass sideslip angle, is the road adhesion coefficient, is the acceleration due to gravity.

[0026] In some embodiments, when determining the actual center of mass sideslip angle according to the state parameter, the state parameter is input into the following formula to obtain the actual center of mass sideslip angle, including:

[0027] ,

[0028] in, is the actual center of mass sideslip angle, is the lateral acceleration, is the longitudinal velocity, is the yaw angular velocity.

[0029] In some embodiments, when calculating the center of mass sideslip angle compensation value according to the angle difference and the vehicle control parameter, the angle difference and the vehicle control parameter are substituted into the following formula to obtain the center of mass sideslip angle compensation value, including:

[0030] ,

[0031] in, is the mass center sideslip angle compensation value, is the vehicle control coefficient, is the angle difference, is the integral control coefficient.

[0032] In some embodiments, when calculating the yaw rate compensation value according to the angular velocity difference and the vehicle control parameter, the angular velocity difference and the vehicle control parameter are substituted into the following formula to obtain the yaw rate compensation value, including:

[0033] ,

[0034] in, is the yaw rate compensation value, is the vehicle control coefficient, is the angular velocity difference, is the integral control coefficient.

[0035] In some embodiments, obtaining the limiting parameter of the vehicle includes: obtaining the slip ratio of the vehicle; and determining the limiting parameter according to the state parameter and the slip ratio.

[0036] In some embodiments, the limiting parameter is determined based on the state parameter and the slip rate, including: fitting a slip rate-road adhesion coefficient mapping relationship based on the state parameter; if the slip rate is within a first preset slip rate range, using the road adhesion coefficient corresponding to the preset slip rate value as the first limiting parameter; if the slip rate is within a second preset slip rate range, using the road adhesion coefficient corresponding to the preset slope value of the mapping relationship as the second limiting parameter.

[0037] In some embodiments, obtaining the slip rate of the vehicle includes:

[0038] ,

[0039] in, is the slip ratio, is the vehicle speed, For wheel speed.

[0040] In some embodiments, controlling the vehicle steering according to the center of mass sideslip angle compensation value and the yaw rate compensation value includes: weighting the center of mass sideslip angle compensation value and the yaw rate compensation value, and determining the compensation angle of the vehicle according to the weighting coefficient; and controlling the vehicle steering according to the compensation angle.

[0041] In some embodiments, when determining the front wheel compensation angle according to the weighting coefficient, the weighting coefficient, the center of mass sideslip angle compensation value and the yaw rate compensation value are substituted into the following formula to obtain the compensation angle, including:

[0042] ,

[0043] in, is the compensation angle, is the weighting coefficient, is the yaw rate compensation value, is the mass center sideslip angle compensation value.

[0044] In order to achieve the above-mentioned purpose, an embodiment of the second aspect of the present invention proposes a vehicle steering control device, which includes: an acquisition module, used to acquire state parameters and limit parameters of the vehicle; a determination module, used to determine a center of mass sideslip angle compensation value and a yaw angular velocity compensation value according to the state parameters and the limit parameters; and a control module, used to control the steering of the vehicle according to the center of mass sideslip angle compensation value and the yaw angular velocity compensation value.

[0045] According to the steering control device of the vehicle in the embodiment of the present invention, by acquiring the state parameters and limiting parameters of the vehicle, jointly determining the center of mass slip angle compensation value and the yaw angular velocity compensation value according to the state parameters and the limiting parameters, and controlling the vehicle steering according to the center of mass slip angle compensation value and the yaw angular velocity compensation value, on the basis of the center of mass slip angle and yaw angular velocity joint control used in the prior art, by adding the limiting parameters, the influence of the external environment on the vehicle steering is fully taken into account, and the disturbance of the compensation value caused by the real-time changing road friction force is avoided, so that the calculated compensation value is more accurate, can adapt to complex driving conditions, and improves the stability, real-time and versatility of the vehicle steering in the wire control steering system.

[0046] In order to achieve the above-mentioned object, an embodiment of a third aspect of the present invention provides a vehicle, wherein the vehicle comprises the steering control device of the vehicle described in the above-mentioned embodiment.

[0047] According to the vehicle of the embodiment of the present invention, by acquiring the state parameters and limiting parameters of the vehicle, the center of mass sideslip angle compensation value and the yaw angular velocity compensation value are jointly determined according to the state parameters and the limiting parameters, and the vehicle steering is controlled according to the center of mass sideslip angle compensation value and the yaw angular velocity compensation value. On the basis of the joint control of the center of mass sideslip angle and the yaw angular velocity used in the prior art, by adding the limiting parameters, the influence of the external environment on the vehicle steering is fully taken into account, and the disturbance of the compensation value caused by the real-time changing road friction force is avoided. The calculated compensation value is more accurate and can adapt to complex driving conditions, thereby improving the stability, real-time and versatility of the vehicle steering in the wire control steering system.

[0048] In order to achieve the above-mentioned purpose, an embodiment of the fourth aspect of the present invention proposes a computer-readable storage medium, on which a vehicle steering control program is stored. When the vehicle steering control program is executed by a processor, the vehicle steering control method described in the above-mentioned embodiment is implemented.

[0049] In order to achieve the above-mentioned purpose, an embodiment of the fifth aspect of the present invention proposes a computer program product, which includes a computer program. When the computer program is executed by a processor, it implements the vehicle steering control method described in the above-mentioned embodiment.

[0050] According to the computer program product of the embodiment of the present invention, by acquiring the state parameters and limiting parameters of the vehicle, the center of mass sideslip angle compensation value and the yaw angular velocity compensation value are jointly determined according to the state parameters and the limiting parameters, and the vehicle steering is controlled according to the center of mass sideslip angle compensation value and the yaw angular velocity compensation value. On the basis of the joint control of the center of mass sideslip angle and the yaw angular velocity used in the prior art, by adding the limiting parameters, the influence of the external environment on the vehicle steering is fully considered, and the disturbance of the compensation value caused by the real-time changing road friction force is avoided. The calculated compensation value is more accurate and can adapt to complex driving conditions, thereby improving the stability, real-time and versatility of the vehicle steering in the wire control steering system.

[0051] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0053] Figure 1 is a flow chart of a vehicle steering control method according to an embodiment of the present invention;

[0054] Figure 2 is a schematic diagram of a slip ratio-road adhesion coefficient mapping relationship according to an embodiment of the present invention;

[0055] Figure 3 is a flow chart of a vehicle steering control method according to a specific embodiment of the present invention;

[0056] Figure 4 is a structural block diagram of a vehicle steering control device according to an embodiment of the present invention;

[0057] Figure 5 is a structural block diagram of a vehicle according to an embodiment of the present invention. Description of the drawings:

[0059] A steering control device 2 of a vehicle;

[0060] Acquisition module 21; determination module 22; control module 23;

[0061] Vehicle 3. DETAILED DESCRIPTION

[0062] Embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. Embodiments of the present invention are described in detail below.

[0063] With the advancement of vehicle steering technology, from the initial mechanical steering and hydraulic steering to the commonly used electric power steering, the foreseeable trend of future steering technology is towards wire-controlled steering. Wire-controlled steering eliminates the mechanical connection in the traditional structure and uses electrical signals to simulate and transmit information. This can not only improve safety performance and assist high-level autonomous driving functions, but also assist the development of chassis integration, thereby reducing production costs.

[0064] Steer-by-wire mainly includes three aspects: road feel simulation, variable transmission ratio adjustment and active steering. Among them, active steering, that is, dynamic stability control strategy, includes active front steering system (Active Front Steering System, AFS), active rear steering (Active Rear Steering, ARS) and four-wheel steering system (Four-Wheel Steering System, 4WS). By changing the angle of the vehicle's steering wheel and the tire force, the stability of the vehicle is dynamically controlled. Usually, active front wheel angle AFS is the most common. In order to improve the reliability and safety of operation, the calculation of the angle compensation output by AFS is extremely important. How to obtain the front wheel compensation angle that makes the vehicle body in the most stable state is one of the problems that need to be solved urgently in the existing steer-by-wire system.

[0065] In the related art, information parameters of the vehicle's current condition are obtained, and the information parameters and the desired center of mass sideslip angle are input into the center of mass sideslip angle / yaw rate sliding mode controller, and weighted at the same time to obtain an additional front wheel steering angle control value δ to compensate for the front wheel steering angle. This technology uses both the center of mass sideslip angle and the yaw rate as input quantities for control, which enhances the stability of applicability. However, it does not take into account the applicability of the weighted values ​​of the two to the system under different circumstances, and the impact of the real-time change of the road adhesion coefficient on its ideal value when calculating the ideal value.

[0066] Alternatively, the current state information of the vehicle is substituted into a two-degree-of-freedom vehicle model for solution and correction to obtain a corrected desired yaw rate and a corrected sideslip angle of the center of mass; the corrected desired yaw rate and the corrected desired sideslip angle of the center of mass are respectively input into a yaw rate self-disturbance controller and a sideslip angle self-disturbance controller of the center of mass to obtain two front wheel angle control values; the two front wheel angle control values ​​are weighted to obtain a final front wheel angle control value; and a control value for controlling the operation of the vehicle is determined based on the final front wheel angle control value. This technology does not rely on an accurate mathematical model of the object, nor does it take into account the applicability of the weighted values ​​of the two to the system under different circumstances.

[0067] Combine the following Figure 1-Figure 3 The vehicle steering control method according to the embodiment of the present invention is described with examples.

[0068] like Figure 1 As shown, the vehicle steering control method of the embodiment of the present invention at least includes steps S1 to S3.

[0069] Step S1, obtaining the state parameters and limiting parameters of the vehicle.

[0070] The limiting parameter is an influencing factor of the road friction on the steering of the vehicle. It can be understood that when the vehicle is on different road surfaces, the corresponding limiting parameters are different.

[0071] In an embodiment, the vehicle state parameters include the longitudinal speed , turning radius , the distance from the front axle to the center of mass of the vehicle , the distance from the rear axle to the center of mass of the vehicle , the quality of the vehicle , the vehicle's front tire cornering stiffness , the vehicle's rear tire cornering stiffness , the sum of the distances from the front axle and the rear axle to the vehicle's center of mass , vehicle speed and front wheel angle , and the limiting parameters include the road adhesion coefficient and the acceleration due to gravity ,By acquiring state parameters, the limiting parameters are added on the basis of ensuring the real-time ,performance of the data, and the influence of different road surfaces on the ,vehicle steering control is considered, thereby improving the accuracy of the ,vehicle steering control.

[0072] Step S2, determining a compensation value for the sideslip angle of the center of mass and a compensation value for the yaw rate according to the state parameter and the limit parameter.

[0073] In the embodiment, after the state parameters and the limit parameters of the vehicle are obtained, the target control value of the center of mass slip angle and the target control value of the yaw angular velocity are jointly determined according to the state parameters and the limit parameters, and the situation that the target control value changes with the change of the limit parameters is fully considered, and the actual control value of the center of mass slip angle and the actual control value of the yaw angular velocity are obtained in real time, and the center of mass slip angle compensation value is determined according to the difference between the target control value of the center of mass slip angle and the actual control value of the center of mass slip angle, for example, recorded as Similarly, the yaw rate compensation value is determined according to the difference between the yaw rate target control value and the yaw rate actual control value, for example, as , by determining the mass center side slip angle compensation value according to the state parameters and limit parameters and yaw rate compensation value On the basis of real-time adjustment of the sideslip angle and yaw rate of the center of mass, the disturbance of the target control value caused by the real-time changing road friction is avoided, and the calculated compensation value can adapt to complex driving conditions.

[0074] Step S3, controlling the vehicle steering according to the center of mass sideslip angle compensation value and the yaw rate compensation value.

[0075] In the embodiment, it is considered that vehicle stability control is divided into two types of problems. One is the track keeping problem. The track problem can be described by the center of mass sideslip angle, that is, the entire vehicle is regarded as a particle. Under a small yaw angular velocity, the center of mass sideslip angle of the vehicle is mainly determined by the longitudinal force and lateral force acting on the tire; the other is the stability problem, that is, the yaw angular velocity problem, which is interrelated with the track keeping problem.

[0076] Therefore, when the two compensation values, namely the center of mass side slip angle compensation value and yaw rate compensation value After obtaining them, it is necessary to obtain the wheel state at this time, considering the sideslip angle and yaw rate of the center of mass in different vehicle states. The impact on vehicle stability is different, and the compensation value of the center of mass side slip angle is adjusted according to different vehicle conditions. and yaw rate compensation value Assign different weights and compensate for the center of mass slip angle according to the weight assignment. and yaw rate compensation value Control the vehicle's steering to maintain the vehicle body stability in real time while improving the safety performance of the vehicle's steering control.

[0077] According to the steering control method of the vehicle in the embodiment of the present invention, by acquiring the state parameters and limiting parameters of the vehicle, the center of mass sideslip angle compensation value and the yaw angular velocity compensation value are jointly determined according to the state parameters and the limiting parameters, and the vehicle steering is controlled according to the center of mass sideslip angle compensation value and the yaw angular velocity compensation value. On the basis of the joint control of the center of mass sideslip angle and the yaw angular velocity used in the prior art, by adding the limiting parameters, the influence of the external environment on the vehicle steering is fully considered, and the disturbance of the compensation value caused by the real-time changing road friction force is avoided. The calculated compensation value is more accurate and can adapt to complex driving conditions, thereby improving the stability, real-time and versatility of the vehicle steering in the wire control steering system.

[0078] In some embodiments, a center of mass slip angle compensation value and a yaw rate compensation value are determined according to state parameters and limiting parameters, including: determining a target center of mass slip angle and a target yaw rate according to the state parameters and limiting parameters; determining an actual center of mass slip angle according to the state parameters; calculating an angular difference between the target center of mass slip angle and the actual center of mass slip angle, and calculating a center of mass slip angle compensation value according to the angular difference and vehicle control parameters; calculating an angular velocity difference between a target yaw rate and an actual yaw rate, and calculating a yaw rate compensation value according to the angular velocity difference and vehicle control parameters.

[0079] In an embodiment, after the state parameters and the limit parameters of the vehicle are acquired, the target center of mass sideslip angle and the target yaw rate are determined according to the state parameters and the limit parameters to determine two target control values.

[0080] Since the device for measuring the sideslip angle of the center of mass is relatively expensive, for general vehicles, the value can be estimated by the integration method based on the state parameters, and the value is determined as the actual sideslip angle β of the center of mass. If there is a corresponding sensor, it can be directly obtained; the actual yaw angular velocity can be directly obtained by the inertial measurement unit (IMU) to determine the two actual control values.

[0081] Get vehicle control parameters including vehicle control coefficients , integral control coefficient , calculate the target center of mass sideslip angle and the actual center of mass sideslip angle The angle difference , according to the angle difference Calculate the center of mass sideslip angle compensation value based on vehicle control parameters Similarly, calculate the angular velocity difference between the target yaw rate and the actual yaw rate , according to the angular velocity difference Calculate the yaw rate compensation value using the vehicle control parameters By applying vehicle control parameters such as proportional, integral, PI control parameters to the center of mass sideslip angle and yaw rate control, the error value can be reduced to a certain extent, thereby improving the safety performance of vehicle steering control.

[0082] In some embodiments, the state parameters include a first state parameter, and the target yaw rate is determined based on the state parameters and the limit parameter, including: determining a theoretical target yaw rate based on the first state parameter; determining a limited target yaw rate based on the first state parameter and the limit parameter; and taking the smaller value of the theoretical target yaw rate and the limited target yaw rate as the target yaw rate.

[0083] In an embodiment, obtaining the first state parameter includes the longitudinal speed , turning radius , the distance from the front axle to the center of mass of the vehicle , the distance from the rear axle to the center of mass of the vehicle , the quality of the vehicle , the vehicle's front tire cornering stiffness , the vehicle's rear tire cornering stiffness , the sum of the distances from the front axle and the rear axle to the vehicle's center of mass , vehicle speed and front wheel angle Then, the first state parameter is brought into the two-degree-of-freedom vehicle model to obtain the theoretical target yaw rate, which can be expressed as ; and according to the first state parameter including the derivative of the longitudinal velocity , and the limiting parameters include the road adhesion coefficient and the acceleration due to gravity The calculated limit target yaw rate is, for example, , compared with the theoretical target yaw rate and the limit target yaw rate The size relationship of the theoretical target yaw angular velocity and the limit target yaw rate The smaller value of is used as the target yaw rate, and the determined target yaw rate meets the current road conditions.

[0084] In some embodiments, the state parameter includes a second state parameter, and the target center of mass sideslip angle is determined based on the state parameter and the limiting parameter, including: determining a theoretical target center of mass sideslip angle based on the second state parameter; determining a limit target center of mass sideslip angle based on the limiting parameter; and taking the smaller value between the theoretical target center of mass sideslip angle and the limit target center of mass sideslip angle as the target center of mass sideslip angle.

[0085] In an embodiment, obtaining the second state parameter includes the distance from the front axle to the center of mass of the vehicle. , the distance from the rear axle to the center of mass of the vehicle , the quality of the vehicle , the vehicle's front tire cornering stiffness , the vehicle's rear tire cornering stiffness , vehicle speed , front wheel angle Then, the second state parameter is introduced into the two-degree-of-freedom vehicle model to obtain the theoretical target center of mass slip angle, which can be expressed as , and according to the limiting parameters including the road adhesion coefficient and the acceleration due to gravity The calculated limit target center of mass side slip angle is recorded as , compared with the theoretical target center of mass sideways angle and limit target center of mass slip angle The size relationship of the theoretical target center of mass is and limit target center of mass slip angle The smaller value in is taken as the target center of mass sideslip angle, and the determined target center of mass sideslip angle conforms to the current road condition.

[0086] In some embodiments, obtaining the first state parameter includes the longitudinal speed , turning radius , the distance from the front axle to the center of mass of the vehicle , the distance from the rear axle to the center of mass of the vehicle , the quality of the vehicle , the vehicle's front tire cornering stiffness , the vehicle's rear tire cornering stiffness , the sum of the distances from the front axle and the rear axle to the vehicle's center of mass , vehicle speed and front wheel angle Then, the above first state parameters are brought into the two-degree-of-freedom vehicle model to obtain the theoretical target yaw angular velocity , the calculation formula is as follows:

[0087] .

[0088] In some embodiments, obtaining the first state parameter includes the derivative of the longitudinal velocity , and the limiting parameters include the road adhesion coefficient and the acceleration due to gravity Then, the first state parameter and the limit parameter are substituted into the following formula to obtain the limit target yaw angular velocity: , the calculation formula is as follows:

[0089] ,

[0090] By calculating the limit target yaw rate , determine the yaw angular velocity after passing the ground friction limit, fully consider the influence of the outside world, and further obtain a more accurate angle through the ground friction limit to ensure the correctness and real-time performance of the steering function.

[0091] In some embodiments, obtaining the second state parameter includes the distance from the front axle to the center of mass of the vehicle. , the distance from the rear axle to the center of mass of the vehicle , the quality of the vehicle , the vehicle's front tire cornering stiffness , the vehicle's rear tire cornering stiffness , vehicle speed , front wheel angle Then, the above second state parameter is brought into the two-degree-of-freedom vehicle model to obtain the theoretical target center of mass sideslip angle , the calculation formula is as follows:

[0092] .

[0093] In some embodiments, since there is no clear formula for the mass center side slip angle limit, the limit parameters include the road adhesion coefficient and the acceleration due to gravity Then, the above limit parameters are substituted into the following formula to obtain the limit target center of mass side slip angle , limit target center of mass sideways angle The calculation formula is as follows:

[0094] ,

[0095] By calculating the limit target center of mass slip angle , determine the sideslip angle of the center of mass after the ground friction limit, fully consider the influence of the outside world, and further obtain a more accurate angle through the ground friction limit to ensure the correctness and real-time performance of the steering function.

[0096] Limit target yaw rate and limit target center of mass slip angle It can accurately control the vehicle to run on roads with poor road conditions and large friction resistance, such as muddy country roads. At the same time, the method of calculating the limit value can also be used in other systems, with high versatility.

[0097] In some embodiments, the definition of the center of mass sideslip angle is as follows:

[0098] ,

[0099] in, is the lateral velocity, is the longitudinal speed.

[0100] The lateral acceleration of the vehicle is the sum of the centripetal acceleration and the lateral translation acceleration, that is:

[0101] ,

[0102] in, is the yaw angular velocity, is the lateral translation acceleration, is the centripetal acceleration.

[0103] Therefore, the lateral acceleration Integrate to get the lateral velocity The expression is:

[0104] ,

[0105] Substituting the above formula into the definition formula of the center of mass sideslip angle, the actual center of mass sideslip angle can be determined The calculation formula is:

[0106] .

[0107] In some embodiments, the angle difference is obtained After the vehicle control parameters are calculated, the angle difference Substitute the vehicle control parameters into the following formula to obtain the center of mass sideslip angle compensation value , compensation value of the mass center slip angle The calculation formula is as follows:

[0108] ,

[0109] in, is the mass center sideslip angle compensation value, is the vehicle control coefficient, is the angle difference, is the integral control coefficient. By determining the compensation value of the mass center side slip angle , reducing the gap between the current value and the target value, reducing the error value to a certain extent, thereby improving the safety performance of vehicle steering control.

[0110] In some embodiments, the angular velocity difference is obtained After the vehicle control parameters are calculated, the angular velocity difference Substitute the vehicle control parameters into the following formula to obtain the yaw rate compensation value , yaw rate compensation value The calculation formula is as follows:

[0111] ,

[0112] in, is the yaw rate compensation value, is the vehicle control coefficient, is the angular velocity difference, is the integral control coefficient. By determining the yaw rate compensation value , reducing the gap between the current value and the target value, reducing the error value to a certain extent, thereby improving the safety performance of vehicle steering control.

[0113] In some embodiments, obtaining the limiting parameters of the vehicle includes: obtaining the slip ratio of the vehicle; and determining the limiting parameters according to the state parameters and the slip ratio.

[0114] In an embodiment, when obtaining the limiting parameters of a vehicle, it is necessary to first determine the slip rate of the vehicle. When the slip rate is in different ranges, the corresponding limiting parameters are determined based on the relationship between the state parameters and the slip rate. By obtaining the limiting parameters, the influence of different road surfaces on the vehicle steering control is taken into account, thereby improving the accuracy of the vehicle steering control.

[0115] In some embodiments, the limiting parameter is determined based on the state parameter and the slip rate, including: fitting the slip rate-road adhesion coefficient mapping relationship based on the state parameter; if the slip rate is within a first preset slip rate range, using the road adhesion coefficient corresponding to the preset slip rate value as the first limiting parameter; if the slip rate is within a second preset slip rate range, using the road adhesion coefficient corresponding to the preset slope value of the mapping relationship as the second limiting parameter.

[0116] In the embodiment, after obtaining the slip rate of the vehicle, the slip rate-road adhesion coefficient mapping relationship is fitted by data fitting according to state parameters including the wheel speed, vehicle speed, ground friction and other parameters of the vehicle, such as: Figure 2 As shown, if the slip rate fluctuates within a first preset slip rate range, for example, 0-20%, the vehicle is considered to be in a stable zone, and the road adhesion coefficient corresponding to a preset slip rate value, for example, 20%, is used as a first limiting parameter; if the slip rate fluctuates within a second preset slip rate range, for example, 20-100%, the vehicle is considered to be in an unstable zone, and the road adhesion coefficient corresponding to a preset slope value, for example, 0, of the mapping relationship is used as a second limiting parameter. The road adhesion coefficient with the largest value determined by the above method is the limiting parameter.

[0117] In some embodiments, the vehicle speed is obtained and wheel speed Then, the vehicle speed and wheel speed Substitute the following formula to get the slip rate , the calculation formula is as follows:

[0118] .

[0119] In some embodiments, the vehicle steering is controlled according to the center of mass sideslip angle compensation value and the yaw rate compensation value, including: weighting the center of mass sideslip angle compensation value and the yaw rate compensation value, determining the compensation angle of the vehicle according to the weighting coefficient; and controlling the vehicle steering according to the compensation angle.

[0120] In an embodiment, the center of mass sideslip angle compensation value is obtained. and yaw rate compensation value After that, it is necessary to assign a weighted proportion to it. When the vehicle's center of mass slip angle is small, the gain of the vehicle's yaw rate and steering wheel angle is sufficient to characterize the vehicle's stability. At this time, the yaw rate control can dominate, and the corresponding weighted coefficient The value is small; however, when the mass center side slip angle is large, for example, more than ±5°, the weighting coefficient of the mass center side slip angle should be increased. Similarly, on surfaces with low road adhesion, the weighting factor of the center of mass slip angle is Should be increased, weighting coefficient The specific value can be obtained through actual vehicle debugging and subjective evaluation, and finally obtained through a two-dimensional table lookup.

[0121] In some embodiments, the weighting coefficient is obtained Then, the weighting coefficient , Mass center side slip angle compensation value and yaw rate compensation value Substitute the following formula to get the compensation angle , compensation angle The calculation formula is as follows:

[0122] ,

[0123] Output compensation angle After being applied to the wheels, it ensures that the body of the car can reach a relatively stable state under different circumstances.

[0124] Reference below Figure 3 The vehicle control method according to the embodiment of the present invention is described with examples.

[0125] like Figure 3 As shown, the vehicle control method of the embodiment of the present invention at least includes steps S11 to S22.

[0126] Step S11, obtaining the state parameters of the vehicle.

[0127] Step S12, obtaining the slip ratio of the vehicle.

[0128] Step S13, fitting the slip ratio-road adhesion coefficient mapping relationship according to the state parameters.

[0129] Step S14, determining whether the slip ratio is within a first preset slip ratio range, if so, executing step S15; otherwise, executing step S16.

[0130] Step S15: taking the road adhesion coefficient corresponding to the preset slip ratio as the first limiting parameter.

[0131] Step S16: The road adhesion coefficient corresponding to the preset slope value of the mapping relationship is used as the second limiting parameter.

[0132] Step S17, determining a theoretical target yaw rate according to the first state parameter; determining a limit target yaw rate according to the first state parameter and the limit parameter; and taking the smaller value between the theoretical target yaw rate and the limit target yaw rate as the target yaw rate.

[0133] Step S18, calculating the angular velocity difference between the target yaw velocity and the actual yaw velocity, and calculating the yaw velocity compensation value according to the angular velocity difference and the vehicle control parameters.

[0134] Step S19, determining a theoretical target center-of-mass slip angle according to the second state parameter; determining a limit target center-of-mass slip angle according to the limit parameter; and taking the smaller value of the theoretical target center-of-mass slip angle and the limit target center-of-mass slip angle as the target center-of-mass slip angle.

[0135] Step S20, determining the actual sideslip angle of the center of mass according to the state parameters.

[0136] Step S21, calculating the angle difference between the target center of mass slip angle and the actual center of mass slip angle, and calculating the center of mass slip angle compensation value according to the angle difference and the vehicle control parameters.

[0137] Step S22, weighting the center of mass sideslip angle compensation value and the yaw rate compensation value, determining the compensation turning angle of the vehicle according to the weighting coefficient; and controlling the steering of the vehicle according to the compensation turning angle.

[0138] According to the steering control method of the vehicle in the embodiment of the present invention, by acquiring the state parameters and limiting parameters of the vehicle, the center of mass sideslip angle compensation value and the yaw angular velocity compensation value are jointly determined according to the state parameters and the limiting parameters, and the vehicle steering is controlled according to the center of mass sideslip angle compensation value and the yaw angular velocity compensation value. On the basis of the joint control of the center of mass sideslip angle and the yaw angular velocity used in the prior art, by adding the limiting parameters, the influence of the external environment on the vehicle steering is fully considered, and the disturbance of the compensation value caused by the real-time changing road friction force is avoided. The calculated compensation value is more accurate and can adapt to complex driving conditions, thereby improving the stability, real-time and versatility of the vehicle steering in the wire control steering system.

[0139] Combine the following Figure 4 A steering control device 2 for a vehicle according to an embodiment of the present invention will be described.

[0140] like Figure 4 As shown, the vehicle steering control device of the embodiment of the present invention includes: an acquisition module 21, a determination module 22 and a control module 23, wherein:

[0141] The acquisition module 21 is used to obtain the state parameters and limit parameters of the vehicle; the determination module 22 is used to determine the center of mass sideslip angle compensation value and the yaw angular velocity compensation value according to the state parameters and the limit parameters; the control module 23 is used to control the vehicle steering according to the center of mass sideslip angle compensation value and the yaw angular velocity compensation value.

[0142] According to the steering control device 2 of the vehicle in the embodiment of the present invention, by acquiring the state parameters and limiting parameters of the vehicle, jointly determining the center of mass slip angle compensation value and the yaw angular velocity compensation value according to the state parameters and the limiting parameters, and controlling the vehicle steering according to the center of mass slip angle compensation value and the yaw angular velocity compensation value, on the basis of the center of mass slip angle and yaw angular velocity joint control used in the prior art, by adding the limiting parameters, the influence of the external environment on the vehicle steering is fully taken into account, and the disturbance of the compensation value caused by the real-time changing road friction force is avoided, so that the calculated compensation value is more accurate, can adapt to complex driving conditions, and improves the stability, real-time and versatility of the vehicle steering in the wire control steering system.

[0143] Combine the following Figure 5 A vehicle 3 according to an embodiment of the present invention will be described.

[0144] like Figure 5 As shown, the vehicle 3 according to the embodiment of the present invention includes the vehicle steering control device 2 according to the above embodiment.

[0145] According to the vehicle 3 of the embodiment of the present invention, by obtaining the state parameters and limiting parameters of the vehicle, the center of mass sideslip angle compensation value and the yaw angular velocity compensation value are jointly determined according to the state parameters and the limiting parameters, and the vehicle steering is controlled according to the center of mass sideslip angle compensation value and the yaw angular velocity compensation value. On the basis of the joint control of the center of mass sideslip angle and the yaw angular velocity used in the prior art, by adding the limiting parameters, the influence of the external environment on the vehicle steering is fully taken into account, and the disturbance of the compensation value caused by the real-time changing road friction force is avoided. The calculated compensation value is more accurate and can adapt to complex driving conditions, thereby improving the stability, real-time and versatility of the vehicle steering in the wire control steering system.

[0146] The following describes a computer-readable storage medium according to an embodiment of the present invention.

[0147] The computer-readable storage medium of the embodiment of the present invention stores a vehicle steering control program, and when the vehicle steering control program is executed by the processor, the vehicle steering control method of the above embodiment is implemented.

[0148] The following describes a computer program product according to an embodiment of the present invention.

[0149] The computer program product of the embodiment of the present invention includes a computer program, and when the computer program is executed by a processor, the vehicle steering control method of the above embodiment is implemented.

[0150] According to the computer program product of the embodiment of the present invention, by acquiring the state parameters and limiting parameters of the vehicle, the center of mass sideslip angle compensation value and the yaw angular velocity compensation value are jointly determined according to the state parameters and the limiting parameters, and the vehicle steering is controlled according to the center of mass sideslip angle compensation value and the yaw angular velocity compensation value. On the basis of the joint control of the center of mass sideslip angle and the yaw angular velocity used in the prior art, by adding the limiting parameters, the influence of the external environment on the vehicle steering is fully considered, and the disturbance of the compensation value caused by the real-time changing road friction force is avoided. The calculated compensation value is more accurate and can adapt to complex driving conditions, thereby improving the stability, real-time and versatility of the vehicle steering in the wire control steering system.

[0151] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0152] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A vehicle steering control method, characterized in that: include: Acquiring state parameters and limiting parameters of the vehicle, wherein acquiring the limiting parameters of the vehicle includes: acquiring the slip rate of the vehicle; fitting a slip rate-road adhesion coefficient mapping relationship according to the state parameters; if the slip rate is within a first preset slip rate range, taking the slip rate as a road adhesion coefficient corresponding to a preset slip rate value as the first limiting parameter; if the slip rate is within a second preset slip rate range, taking the slope of the mapping relationship as a road adhesion coefficient corresponding to a preset slope value as the second limiting parameter; Determine a mass center sideslip angle compensation value and a yaw angular velocity compensation value according to the state parameter and the limit parameter; The vehicle steering is controlled according to the center of mass sideslip angle compensation value and the yaw rate compensation value.

2. The vehicle steering control method according to claim 1, characterized in that: Determining a center of mass sideslip angle compensation value and a yaw rate compensation value according to the state parameter and the limit parameter includes: Determine a target center of mass sideslip angle and a target yaw rate according to the state parameter and the limit parameter; Determine the actual center of mass sideslip angle according to the state parameter; Calculating an angle difference between the target center of mass sideslip angle and the actual center of mass sideslip angle, and calculating a center of mass sideslip angle compensation value according to the angle difference and a vehicle control parameter; An angular velocity difference between the target yaw velocity and the actual yaw velocity is calculated, and the yaw velocity compensation value is calculated according to the angular velocity difference and a vehicle control parameter.

3. The vehicle steering control method according to claim 2, characterized in that: The state parameter includes a first state parameter, and determining a target yaw angular velocity according to the state parameter and the limit parameter includes: determining a theoretical target yaw rate according to the first state parameter; Determine a limit target yaw rate according to the first state parameter and the limit parameter; A smaller value between the theoretical target yaw rate and the limit target yaw rate is used as the target yaw rate.

4. The vehicle steering control method according to claim 2, characterized in that: The state parameter includes a second state parameter, and determining a target center of mass sideslip angle according to the state parameter and a limit parameter includes: Determine a theoretical target center of mass sideslip angle according to the second state parameter; Determine a limit target center of mass sideslip angle according to the limit parameter; The smaller value between the theoretical target center of mass sideslip angle and the limit target center of mass sideslip angle is used as the target center of mass sideslip angle.

5. The vehicle steering control method according to claim 3, characterized in that: When determining the theoretical target yaw rate according to the first state parameter, the first state parameter is substituted into the following formula to obtain the theoretical target yaw rate, including: ， in, is the theoretical target yaw rate, is the longitudinal velocity, is the turning radius, is the distance from the front axle to the center of mass of the vehicle, is the distance from the rear axle to the center of mass of the vehicle, is the mass of the vehicle, is the vehicle's front tire cornering stiffness, is the vehicle's rear tire cornering stiffness, is the sum of the distances from the front axle and the rear axle to the center of mass of the vehicle, is the vehicle speed, is the front wheel turning angle.

6. The vehicle steering control method according to claim 3, characterized in that: When determining the limited target yaw rate according to the first state parameter and the limit parameter, the first state parameter and the limit parameter are substituted into the following formula to obtain the limited target yaw rate, including: ， in, is the limit target yaw rate, is the road adhesion coefficient, is the acceleration due to gravity, is the derivative of the longitudinal velocity.

7. The vehicle steering control method according to claim 4, characterized in that: When determining the theoretical target center of mass sideslip angle according to the second state parameter, the second state parameter is substituted into the following formula to obtain the theoretical target center of mass sideslip angle, including: ， in, is the theoretical target center of mass sideslip angle, is the distance from the front axle to the center of mass, is the distance from the rear axle to the center of mass, is the mass of the vehicle, is the front tire cornering stiffness, is the rear tire cornering stiffness, is the vehicle speed, is the front wheel turning angle.

8. The vehicle steering control method according to claim 4, characterized in that: When determining the limit target center of mass sideslip angle according to the limit parameter, the limit parameter is substituted into the following formula to obtain the limit target center of mass sideslip angle, including: ， in, is the limit target center of mass sideslip angle, is the road adhesion coefficient, is the acceleration due to gravity.

9. The vehicle steering control method according to claim 2, characterized in that: When determining the actual center of mass sideslip angle according to the state parameter, the state parameter is input into the following formula to obtain the actual center of mass sideslip angle, including: ， in, is the actual center of mass sideslip angle, is the lateral acceleration, is the longitudinal velocity, is the yaw angular velocity.

10. The vehicle steering control method according to claim 2, characterized in that: When calculating the mass center sideslip angle compensation value according to the angle difference and the vehicle control parameter, the angle difference and the vehicle control parameter are substituted into the following formula to obtain the mass center sideslip angle compensation value, including: ， in, is the mass center sideslip angle compensation value, is the vehicle control coefficient, is the angle difference, is the integral control coefficient.

11. The vehicle steering control method according to claim 2, characterized in that: When calculating the yaw rate compensation value according to the angular velocity difference and the vehicle control parameter, the angular velocity difference and the vehicle control parameter are substituted into the following formula to obtain the yaw rate compensation value, including: ， in, is the yaw rate compensation value, is the vehicle control coefficient, is the angular velocity difference, is the integral control coefficient.

12. The vehicle steering control method according to claim 1, characterized in that: Obtaining the slip rate of the vehicle, comprising: ， in, is the slip ratio, is the vehicle speed, For wheel speed.

13. The vehicle steering control method according to claim 1, characterized in that: Controlling vehicle steering according to the center of mass sideslip angle compensation value and the yaw rate compensation value includes: Weighting the center of mass sideslip angle compensation value and the yaw rate compensation value, and determining a compensation turning angle of the vehicle according to a weighting coefficient; The vehicle steering is controlled according to the compensation angle.

14. The vehicle steering control method according to claim 13, characterized in that: When determining the front wheel compensation angle according to the weighted coefficient, the weighted coefficient, the center of mass sideslip angle compensation value and the yaw rate compensation value are substituted into the following formula to obtain the compensation angle, including: ， in, is the compensation angle, is the weighting coefficient, is the yaw rate compensation value, is the mass center sideslip angle compensation value.

15. A vehicle steering control device, characterized in that: include: an acquisition module, configured to acquire state parameters and limiting parameters of the vehicle, wherein acquiring the limiting parameters of the vehicle comprises: acquiring the slip rate of the vehicle; fitting a slip rate-road adhesion coefficient mapping relationship according to the state parameters; if the slip rate is within a first preset slip rate range, taking the slip rate as the road adhesion coefficient corresponding to the preset slip rate value as the first limiting parameter; if the slip rate is within a second preset slip rate range, taking the slope of the mapping relationship as the road adhesion coefficient corresponding to the preset slope value as the second limiting parameter; A determination module, used to determine a mass center sideslip angle compensation value and a yaw angular velocity compensation value according to the state parameter and the limit parameter; A control module is used to control the steering of the vehicle according to the center of mass sideslip angle compensation value and the yaw rate compensation value.

16. A vehicle, characterized in that: A vehicle steering control device comprising the vehicle steering control device as claimed in claim 15.

17. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a vehicle steering control program, and when the vehicle steering control program is executed by a processor, the vehicle steering control method according to any one of claims 1 to 14 is implemented.

18. A computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the vehicle steering control method according to any one of claims 1 to 14 is implemented.

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