Steering feeling control method based on steering objective evaluation

Abstract

The invention is suitable for the technical field of automobile steering control, and provides a steering feeling control method based on objective steering evaluation, which comprises the following steps of: firstly, objectively evaluating the steering portability, the steering transient response and the steering central area performance according to the steering operation input of a driver and the motion state of a steering system in combination with the set expected steering feeling; determining the steering motion intensity expected by the driver; secondly, calculating an expected steering system position by taking tracking of the expected steering feeling as a target; thirdly, the steering resistance moment equivalent to the position of a pinion is calculated with tracking of the expected steering system position as the target; and finally, dynamically coupling the equivalent resistance moment with a steering wheel moment applied by a driver, and calculating a steering system target assistance moment capable of realizing a steering feeling expected by the driver. According to the method, steering feeling can be accurately quantified, a control strategy is efficiently adjusted and optimized, the problem that traditional subtraction logic is sensitive to nonlinear interference is effectively solved, and the consistency of steering motion quality is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of automobile steering control, and in particular relates to a steering feeling control method based on objective steering evaluation. Background Art

[0002] Electric power steering (EPS) systems have been widely used in automobiles in recent years. Ensuring good stability and consistent, controllable, and road-adaptive steering feel throughout the lifecycle of mass-produced vehicles has become a major challenge for the automotive industry.

[0003] The invention patent with publication number CN118270005A discloses a steering feel control method based on driving style recognition. It identifies aggressive, normal, and conservative driving styles through fuzzy C-means clustering and BP neural network, and dynamically integrates three basic force curves based on the membership vector. Although this patent realizes the correlation adjustment between driving style and steering torque, it does not establish a deterministic mapping relationship between steering wheel torque and steering movement intensity, and does not consider the differentiated characterization of steering dynamic response under low-speed / high-speed conditions of the vehicle. As a result, the steering force curve design lacks adaptability to working conditions and it is difficult to ensure the consistency of steering movement quality throughout the life cycle. In addition, its force curve correction coefficient relies on experimental calibration, fails to form a closed-loop feedback mechanism, and cannot dynamically compensate for the impact of steering system parameter drift on the control effect.

[0004] Patent publication number CN118046957A discloses an electric power steering system control strategy for steering kinematic quality. This patent aims to address the single-dimensional control problem of current EPS control strategies through the collaborative work of an objectively evaluated steering feel design module, a vehicle steering kinematic control module, and a steering system position control module. However, this control strategy fails to establish a coordinated control mechanism for steering feel, hysteresis-simulated torque, and self-centering performance when implementing steering kinematic quality control. This makes it particularly difficult to achieve dynamic coupling compensation between steering system position and vehicle dynamics under special operating conditions, such as when the driver releases or re-centers the vehicle. This results in insufficient precision in self-centering speed control. Summary of the Invention

[0005] The purpose of the embodiments of the present invention is to provide a steering feel control method based on objective steering evaluation, aiming to solve the problems raised in the above background technology.

[0006] The embodiment of the present invention is implemented as follows: a steering feel control method based on objective steering evaluation includes the following steps:

[0007] Step 1: Based on the driver's steering input and the steering system's motion state, combined with the set desired steering feel, objectively evaluate steering lightness, steering transient response, and steering center zone performance to obtain objective evaluation indicators that truly represent driving intent. Then, the corresponding expected steering motion intensity is retrieved based on the steering style.

[0008] Step 2: Based on the actual steering motion intensity and the expected steering motion intensity, the chassis dynamic sliding surface s1 is designed based on the sliding mode control (SMC) principle to force the vehicle steering motion state to converge along s1; the chassis dynamic switching control rate is generated based on s1 and the expected pinion angle is output.

[0009] Step 3: Adjust the desired pinion angle and the actual pinion angle δ p , design the steering system dynamic sliding surface s2 to ensure that the steering mechanism quickly and accurately tracks the target position; generate the steering system dynamic switching control rate based on s2 and output the expected steering resistance torque Drive the steering system to achieve the desired steering torque And further determine the motor assist control amount.

[0010] In a further technical solution, in step 1, the driver's steering operation input is represented by the steering wheel torque T measured by the sensor. sw (Unit: N·m); the steering system motion state includes the steering wheel angle δ sw (unit: deg), steering wheel angular velocity (unit: deg / s) and steering wheel angular acceleration (Unit: deg / s 2 ); the expected steering motion intensity includes the expected lateral acceleration (in g) and the desired steering wheel angle (Unit: deg).

[0011] In a further technical solution, in step 1, the ideal value range of the objective evaluation index is as follows:

[0012] Lateral acceleration a y 0m / s 2 When the steering wheel torque T sw The gradient is 2.5 to 3 N·m / g; the Sport model uses 3.0 N·m / g to enhance initial steering feedback, while the Comfort model uses 2.6 N·m / g to reduce the steering heaviness.

[0013] Lateral acceleration a y 1m / s 2 When the steering wheel torque T swUse 2.5~3.5N·m; use 2.5N·m at low speed to ensure portability; use 3.5N·m at high speed to ensure stability;

[0014] When the vehicle speed is 0-5km / h, the maximum steering wheel torque is ≤3.5N·m; the comfort type is 2.8N·m; the sports type is 3.2N·m.

[0015] Under step input, the time for lateral acceleration to establish from 0% to 90% of the steady-state value is 0.15 to 0.35 seconds; 0.2 seconds for the sport type and 0.3 seconds for the comfort type.

[0016] In a further technical solution, in step 2, the actual steering motion intensity includes the lateral acceleration a y and steering wheel angle δ sw ;

[0017] The chassis dynamic sliding surface s1 is designed based on the lateral acceleration error and steering wheel angle error:

[0018]

[0019] in, is the desired lateral acceleration, is the desired steering wheel angle, λ1 is a positive coefficient used to adjust the convergence speed;

[0020] Generate chassis dynamics switching control rate based on s1 and output desired pinion angle

[0021] Take the derivative of the sliding surface s1 and substitute it into a y =Gδ sw , the equivalent control item u of the vehicle steering motion control module can be obtained eq1 :

[0022]

[0023] Wherein, J is the inertia of the steering system, B is the damping of the steering system, and K is the stiffness coefficient of the steering system;

[0024] Switch item u sw1 To suppress interference and parameter uncertainty, a sign function or a saturation function is usually used:

[0025] u sw1 =-K sw ·sign(s1)

[0026] Among them, K sw is the switching gain;

[0027] The sign function sign(s1) returns ±1 or 0 according to the value of the sliding surface variable s1, which is used to generate switching control items to achieve rapid convergence of the system state;

[0028]

[0029] The control quantity u1 output by the sliding mode control law is:

[0030] u1=u eq1 +u sw1

[0031] Converted to the desired pinion angle

[0032]

[0033] G is the steering system transmission ratio.

[0034] As a further technical solution, in step 3, the steering system dynamic sliding surface s2 is designed based on the pinion angle error:

[0035]

[0036] in, is the desired pinion angle; λ2 is a positive coefficient used to adjust the convergence speed;

[0037] Generate the steering system dynamics switching control rate based on s2 and output the expected steering resistance torque

[0038] Equivalent control item u eq2 Used to offset the nominal dynamics of the system and ensure that the system state slides along the sliding surface when there is no interference:

[0039]

[0040] Switch item u sw2 To suppress interference and parameter uncertainty, a sign function or a saturation function is usually used:

[0041] u sw2 =-K sw ·sign(s2)

[0042] The sign function sign(s2) returns ±1 or 0 according to the value of the sliding surface variable s2, which is used to generate switching control items to achieve rapid convergence of the system state;

[0043]

[0044] The control quantity u2 output by the sliding mode control law is:

[0045] u2=ueq2 +u sw2

[0046] Based on the sliding surface s2 and the switching control rate, the expected steering resistance torque is:

[0047]

[0048] The expected steering assist torque is:

[0049]

[0050] The embodiment of the present invention provides a steering feel control method based on objective steering evaluation, which has the following beneficial effects:

[0051] (1) This method designs the desired steering feel based on an objective evaluation system, which can accurately quantify the steering feel and efficiently adjust and optimize the control strategy.

[0052] (2) The use of a sliding mode controller ensures the robustness of the vehicle system in the presence of environmental interference or noise. Its anti-vibration measures suppress high-frequency vibration problems and improve the stability and reliability of the system. Using dynamic coupling optimization, a sliding mode compensation term is introduced into the target torque calculation to address the problem that traditional subtraction logic is sensitive to nonlinear interference. Dynamic compensation can effectively address the impact of steering system parameter drift on control performance and ensure the consistency of steering motion quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A schematic diagram of an implementation scheme of a steering feel control method based on objective steering evaluation provided by an embodiment of the present invention;

[0054] Figure 2 Schematic diagram of the implementation scheme of step 1;

[0055] Figure 3 Schematic diagram of the implementation scheme of step 2;

[0056] Figure 4 Schematic diagram of the implementation scheme of step 3. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0058] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0059] like Figure 1-Figure 4As shown, a steering feel control method based on objective steering evaluation is provided in one embodiment of the present invention, comprising the following steps:

[0060] Step 1: Based on the driver's steering input and the steering system's motion state, combined with the set desired steering feel, objectively evaluate steering lightness, steering transient response, and steering center zone performance to obtain objective evaluation indicators that truly represent driving intent. Then, the corresponding expected steering motion intensity is retrieved based on the steering style.

[0061] Step 2: Based on the actual steering motion intensity and the expected steering motion intensity, the chassis dynamic sliding surface s1 is designed based on the sliding mode control (SMC) principle to force the vehicle steering motion state to converge along s1; the chassis dynamic switching control rate is generated based on s1 and the expected pinion angle is output.

[0062] Step 3: Adjust the desired pinion angle and the actual pinion angle δ p , design the steering system dynamic sliding surface s2 to ensure that the steering mechanism quickly and accurately tracks the target position; generate the steering system dynamic switching control rate based on s2 and output the expected steering resistance torque Drive the steering system to achieve the desired steering torque And further determine the motor assist control amount.

[0063] like Figure 2 As shown in FIG. 1 , as a preferred embodiment of the present invention, in step 1, the driver's steering operation input is represented by the steering wheel torque T measured by the sensor. sw (Unit: N·m); the steering system motion state includes the steering wheel angle δ sw (unit: deg), steering wheel angular velocity (unit: deg / s) and steering wheel angular acceleration (Unit: deg / s 2 ); the expected steering motion intensity includes the expected lateral acceleration (in g) and the desired steering wheel angle (Unit: deg).

[0064] As a preferred embodiment of the present invention, in step 1, the ideal value range of the objective evaluation index is as follows:

[0065] Lateral acceleration a y 0m / s 2 When the steering wheel torque T sw The gradient is 2.5 to 3 N·m / g. The Sport model uses 3.0 N·m / g to enhance initial steering feedback, while the Comfort model uses 2.6 N·m / g to reduce the steering heaviness.

[0066] Lateral acceleration a y 1m / s 2 When the steering wheel torque T sw Use 2.5 to 3.5 N·m. Use 2.5 N·m at low speed to ensure portability; use 3.5 N·m at high speed to ensure stability.

[0067] At speeds between 0 and 5 km / h, the maximum steering wheel torque is ≤3.5 N·m. The Comfort model uses 2.8 N·m, while the Sport model uses 3.2 N·m.

[0068] Under step input, the lateral acceleration settling time from 0 to 90% of the steady-state value is 0.15 to 0.35 seconds. The Sport mode takes 0.2 seconds, and the Comfort mode takes 0.3 seconds.

[0069] like Figure 3 As shown in FIG. 1 , as a preferred embodiment of the present invention, in step 2, the actual steering motion intensity includes the lateral acceleration a y and steering wheel angle δ sw ;

[0070] The chassis dynamic sliding surface s1 is designed based on the lateral acceleration error and steering wheel angle error:

[0071]

[0072] in, is the desired lateral acceleration, is the desired steering wheel angle, λ1 is a positive coefficient used to adjust the convergence speed;

[0073] Generate chassis dynamics switching control rate based on s1 and output desired pinion angle

[0074] Take the derivative of the sliding surface s1 and substitute it into a y =Gδ sw , the equivalent control item u of the vehicle steering motion control module can be obtained eq1 :

[0075]

[0076] Wherein, J is the inertia of the steering system, B is the damping of the steering system, and K is the stiffness coefficient of the steering system;

[0077] Switch item u sw1 To suppress interference and parameter uncertainty, a sign function or a saturation function is usually used:

[0078] u sw1 =-K sw ·sign(s1)

[0079] Among them, Ksw is the switching gain;

[0080] The sign function sign(s1) returns ±1 or 0 according to the value of the sliding surface variable s1, which is used to generate switching control items to achieve rapid convergence of the system state;

[0081]

[0082] The control quantity u1 output by the sliding mode control law is:

[0083] u1=u eq1 +u sw1

[0084] Converted to the desired pinion angle

[0085]

[0086] G is the steering system transmission ratio.

[0087] like Figure 4 As shown in FIG. 1 , as a preferred embodiment of the present invention, in step 3, the steering system dynamic sliding surface s2 is designed based on the pinion angle error:

[0088]

[0089] in, is the desired pinion angle; λ2 is a positive coefficient used to adjust the convergence speed;

[0090] Generate the steering system dynamics switching control rate based on s2 and output the expected steering resistance torque

[0091] Equivalent control item u eq2 Used to offset the nominal dynamics of the system and ensure that the system state slides along the sliding surface when there is no interference:

[0092]

[0093] Switch item u sw2 To suppress interference and parameter uncertainty, a sign function or a saturation function is usually used:

[0094] u sw2 =-K sw ·sign(s2)

[0095] The sign function sign(s2) returns ±1 or 0 according to the value of the sliding surface variable s2, which is used to generate switching control items to achieve rapid convergence of the system state;

[0096]

[0097] The control quantity u2 output by the sliding mode control law is:

[0098] u2=u eq2 +u sw2

[0099] Based on the sliding surface s2 and the switching control rate, the expected steering resistance torque is:

[0100]

[0101] The expected steering assist torque is:

[0102]

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A steering feel control method based on objective steering evaluation, characterized in that: The following steps are involved: Step 1: Based on the driver's steering input and the steering system's motion state, combined with the desired steering feel, objectively evaluate steering lightness, steering transient response, and steering center performance to obtain objective evaluation indicators. The corresponding desired steering motion intensity is then retrieved based on the steering style. Step 2: Based on the actual steering motion intensity and the expected steering motion intensity, the chassis dynamic sliding surface s1 is designed based on the sliding mode control principle to force the vehicle steering motion state to converge along s1; the chassis dynamic switching control rate is generated based on s1 and the expected pinion angle is output. Step 3: Adjust the desired pinion angle and the actual pinion angle δ p , design the steering system dynamic sliding surface s2 to make the steering mechanism track the target position; generate the steering system dynamic switching control rate based on s2 and output the expected steering resistance torque Drive the steering system to achieve the desired steering torque And further determine the motor assist control amount.

2. The steering feel control method based on objective steering evaluation according to claim 1, characterized in that: In step 1, the driver's steering input is represented by the steering wheel torque T measured by the sensor. sw ; The steering system motion state includes the steering wheel angle δ sw , steering wheel angular velocity and steering wheel angular acceleration Desired steering movement intensity including desired lateral acceleration and the desired steering wheel angle 3. The steering feel control method based on objective steering evaluation according to claim 2, characterized in that: In step 1, the ideal value range of the objective evaluation index is as follows: Lateral acceleration a y 0m / s 2 When the steering wheel torque T sw The gradient is 2.5 to 3 N·m / g; the sports type takes 3.0 N·m / g, and the comfort type takes 2.6 N·m / g; Lateral acceleration a y 1m / s 2 When the steering wheel torque T sw Take 2.5~3.5N·m; take 2.5N·m at low speed; take 3.5N·m at high speed; When the vehicle speed is 0-5km / h, the maximum steering wheel torque is ≤3.5N·m; the comfort type is 2.8N·m; the sports type is 3.2N·m; Under step input, the time for lateral acceleration to establish from 0% to 90% of the steady-state value is 0.15 to 0.35 seconds; 0.2 seconds for the sport type and 0.3 seconds for the comfort type.

4. The steering feel control method based on objective steering evaluation according to claim 2, characterized in that: In step 2, the actual steering motion intensity includes the lateral acceleration a y and steering wheel angle δ sw ; The chassis dynamic sliding surface s1 is designed based on the lateral acceleration error and steering wheel angle error: in, is the desired lateral acceleration, is the desired steering wheel angle, λ1 is a positive coefficient used to adjust the convergence speed; Generate chassis dynamics switching control rate based on s1 and output desired pinion angle Take the derivative of the sliding surface s1 and substitute it into a y =Gδ sw , the equivalent control item u of the vehicle steering motion control module can be obtained eq1 : Wherein, J is the inertia of the steering system, B is the damping of the steering system, and K is the stiffness coefficient of the steering system; Switch item u sw1 To suppress interference and parameter uncertainty, a sign function or a saturation function is usually used: u sw1 =-K sw ·sign(s1) Among them, K sw is the switching gain; The sign function sign(s1) returns ±1 or 0 according to the value of the sliding surface variable s1, which is used to generate switching control items to achieve rapid convergence of the system state; The control quantity u1 output by the sliding mode control law is: u1=u eq1 +u sw1 Converted to the desired pinion angle G is the steering system transmission ratio.

5. The steering feel control method based on objective steering evaluation according to claim 4, characterized in that: In step 3, the steering system dynamic sliding surface s2 is designed based on the pinion angle error: in, is the desired pinion angle; λ2 is a positive coefficient used to adjust the convergence speed; Generate the steering system dynamics switching control rate based on s2 and output the expected steering resistance torque Equivalent control item u eq2 Used to offset the nominal dynamics of the system and ensure that the system state slides along the sliding surface when there is no interference: Switch item u sw2 To suppress interference and parameter uncertainty, a sign function or a saturation function is usually used: u sw2 =-K sw ·sign(s2) The sign function sign(s2) returns ±1 or 0 according to the value of the sliding surface variable s2, which is used to generate switching control items to achieve rapid convergence of the system state; The control quantity u2 output by the sliding mode control law is: u2=u eq2 +u sw2 Based on the sliding surface s2 and the switching control rate, the expected steering resistance torque is: The expected steering assist torque is:

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