A vehicle steering body posture and handling stability control method

Abstract

The present application relates to a kind of vehicle steering body posture and control method of handling stability, comprising the following steps: the signal input required for control is collected, vehicle total anti-lateral moment is calculated by body posture feedforward-feedback controller, front and rear axle anti-roll moment distribution ratio is calculated by handling stability feedforward-feedback controller, total anti-roll moment and its front and rear axle distribution ratio are calculated, revised by control comprehensive module, finally output each suspension angle vertical force control instruction of vehicle.The present application has the following advantages:1) vehicle body posture control and handling stability control are comprehensively considered, and both are simultaneously optimized;2) vehicle body posture control and handling stability control both use feedback-feedforward, avoid the problem of pure feedforward control or feedback control, so that the overall performance of vehicle is more "natural";3) steering input and road input are decoupled, and four high sensors are saved.

Description

Technical Field

[0001] The present invention relates to the field of vehicle wire-controlled chassis suspension control, and in particular to the field of fully active suspension technology that uses a motor system as a power source and realizes real-time adjustment of the suspension vertical force through a hydraulic system or a mechanical system. Specifically, it relates to a vehicle steering body posture and handling stability control method. Background Art

[0002] In the field of active suspension technology, "slow" active suspension, or air springs, are currently widely used. Air springs offer height adjustment, but because they typically take more than 5 seconds to adjust from their compression limit to their extension limit or vice versa, they have a low control bandwidth and a long response time, making it difficult to meet the requirements for dynamic compensation of vehicle posture. Dual-chamber air springs offer stiffness adjustment, but due to vehicle comfort requirements, the stiffness cannot be set to infinite, and due to physical structural limitations, it is even more impossible to set it to negative stiffness. Therefore, stiffness adjustment can only suppress vehicle steering roll to a certain extent, but cannot continuously control the vehicle's roll motion, let alone produce a roll angle in the opposite direction.

[0003] In the field of semi-active suspension, continuously adjustable shock absorbers are currently widely used. The damping force is a passively generated force, equal to the damping coefficient multiplied by the relative velocity, and its direction is opposite to the relative velocity. Due to the need for comfort, the shock absorber damping cannot be adjusted to infinity, and continuously adjustable shock absorbers do not actively output suspension force. The characteristics of the damping force indicate that the damping force can only reduce the roll rate to a certain extent and cannot produce a roll angle in the opposite direction, thus limiting its effectiveness in controlling vehicle roll.

[0004] Active suspension uses a motor system as its power source and achieves real-time adjustment of the suspension's vertical force through a hydraulic system or a mechanical system. Within the actuator's output capacity, it can quickly, in real time, and in any direction adjust the compression and extension of each suspension, with the potential to improve the vehicle's body posture and handling stability during cornering.

[0005] There are few existing methods involving the integrated consideration of vehicle posture control and handling stability control for fully active suspension. Summary of the Invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a vehicle steering body posture and handling stability control method, which can simultaneously optimize the vehicle steering body posture and handling stability, thereby improving the comfort of the driver and passengers and the safety of the vehicle.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for controlling vehicle steering posture and handling stability comprises the following steps:

[0009] Step 1: Collect control-related vehicle signals, including steering wheel angle, angular velocity, steering torque, and vehicle speed.

[0010] Step 2: The vehicle posture feedforward-feedback controller calculates the total anti-roll moment M of the vehicle Tol , including M Tol_Comp 、M Tol_Norm 、M Tol_Spt wait.

[0011] Sub-step 2-1, the vehicle posture feedforward controller receives signals such as steering wheel angle, angular velocity, steering torque and vehicle speed, and calculates the first anti-roll moment M Ff , including M Ff_Spt 、M Ff_Norm 、M Ff_Spt The calculation method can be a table lookup method or an online calculation method. The table lookup method obtains the optimal control quantity curve through offline simulation in advance and stores it in the software. The current control quantity is obtained by looking up the table through input signals such as steering wheel angle, angular velocity, vehicle speed, etc. The online calculation method can use feedforward controllers including but not limited to the following types G ff :

[0012] Sub-step 2-2, integrate the control variables of the vehicle posture feedforward controller and feedback controller to obtain the total anti-roll moment M of the vehicle Tol , including M Tol_Comp 、M Tol_Norm 、M Tol_Spt Among them, the control variables of the vehicle posture feedforward controller are derived from sub-step 2-1, and the control variables of the vehicle posture feedback controller are derived from sub-step 2-6 (to avoid algebraic loops, the control variables need to be delayed by one cycle). The control variable synthesis methods include superposition method and weighted summation method. Sub-step 2-3, output the total anti-roll moment M of the vehicle Tol , including M Tol_Comp 、M Tol_Norm 、M Tol_Spt , on the one hand it is output to step 4, on the other hand it is output to sub-steps 2-4.

[0013] Sub-steps 2-4 estimate the vehicle state based on a nonlinear vehicle dynamics model. The inputs of the nonlinear vehicle dynamics model are vehicle speed, steering wheel angle, and steering wheel speed, and the outputs include lateral acceleration, yaw rate, rear axle center of mass sideslip angle, vehicle roll motion, etc.

[0014] Sub-steps 2-5 perform signal fusion based on the estimated vehicle state and the actual vehicle state measured by the sensors. The signal fusion method is: when the vehicle is in a stable state, the nonlinear vehicle dynamics model is used to calculate the results; when the vehicle is in an unstable state, the actual measured signals of the on-board sensors are used; when the vehicle is between stable and unstable states, a fusion method including the Kalman filter method is used.

[0015] Sub-step 2-6, based on the vehicle state after the signal fusion output from sub-step 2-5, feedback control is performed to calculate and output the anti-roll moment M Ff , including M Ff_Comp 、M Ff_Norm 、M Ff_Spt ,The feedback control methods include table lookup, proportional control, PI control, PD control, PID control, sliding mode control, MPC control, and robust control.

[0016] Step 3: The handling stability feedforward-feedback controller calculates the front and rear axle anti-roll moment distribution ratio f, which includes f suitable for a leisure and comfortable driving style. Comf , suitable for daily driving style Norm , suitable for aggressive driving style Spt . Mainly includes sub-steps 3-1 to 3-4.

[0017] Sub-step 3-1, the handling stability feedforward controller receives signals such as steering wheel angle, angular velocity, steering torque and vehicle speed, and calculates the first front and rear axle anti-roll moment distribution ratio f, including: f Ff_Comf 、f Ff_Norm 、f Ff_Spt The calculation method can be a table lookup method or an online calculation method. The table lookup method obtains the optimal control quantity curve through offline simulation in advance and stores it in the software. The current control quantity is obtained by looking up the table through input signals such as steering wheel angle, angular velocity, vehicle speed, etc. The online calculation method uses a feedforward controller G ff .

[0018] In sub-step 3-2, the handling stability feedback controller receives the measured vehicle yaw rate, lateral acceleration, rear axle center of mass slip angle and other signals, and calculates the second front and rear axle anti-roll moment distribution ratio f, including: f Fb_Comf 、f Fb_Norm 、f Fb_Spt ,The feedback control methods include table lookup, proportional control, PI control, PD control, PID control, sliding mode control, MPC control, and robust control.

[0019] Sub-step 3-3, integrate the control variables of the handling stability feedforward controller and the feedback controller to obtain the front and rear axle anti-roll moment distribution ratio f, including: f Comf 、f Norm、f Spt The control variables of the handling stability feedforward controller are derived from sub-step 3-1, and the control variables of the vehicle body posture feedback controller are derived from sub-step 3-2. Methods for synthesizing control variables include the superposition method and the weighted summation method.

[0020] Sub-steps 3-4, outputting the front and rear axle anti-roll moment distribution ratio f to step 4, include: f Comf 、f Norm 、f Spt .

[0021] Step 4: Body posture control and handling stability control are integrated. This step calculates the final front and rear axle anti-roll moment M. Frt_Comp and M Rr_Comp . Mainly includes sub-steps 4-1 to 4-6.

[0022] Sub-step 4-1, selection of the vehicle's total anti-roll moment, output of the vehicle's total anti-roll moment M Tol Select the appropriate vehicle total anti-roll moment M based on the current driving style evaluation results. Tol , the mapping relationship between driving style and total anti-roll moment should be defined by the OEM.

[0023] Sub-step 4-2: Compensate and correct the total anti-roll moment of the vehicle, and output the corrected total anti-roll moment M Tol_Comp Based on the current vehicle and system states, the total anti-roll moment of the vehicle is compensated and corrected, including but not limited to: ① correction based on the vehicle's available power limit; ② correction based on the motor's available power and available torque; ③ correction based on the active suspension system's fault state; ④ compensation based on the fully active suspension system's efficiency; ⑤ compensation based on the fully active suspension's structural nonlinearity; and ⑥ compensation based on the fully active suspension's actuator inertia.

[0024] Sub-step 4-3, selecting the front and rear axle anti-roll torque distribution ratio, outputs the front and rear axle anti-roll torque distribution ratio f. The appropriate front and rear axle anti-roll torque distribution ratio is selected based on the current driving style assessment results. The mapping relationship between driving style and total anti-roll torque should be defined by the OEM.

[0025] Sub-step 4-4, front and rear axle anti-roll moment distribution ratio f compensation correction, output compensation correction total anti-roll moment distribution ratio f Comp ; According to the current vehicle state and system state, the front and rear axle anti-roll torque distribution ratio f is compensated and corrected, including but not limited to adjusting the front and rear axle anti-roll torque distribution ratio f based on external system requests.

[0026] Sub-steps 4-5: Calculate the front and rear axle anti-roll moment M Frt_Comp and M Rr_Comp :

[0027]

[0028] Sub-steps 4-6: Output the front and rear axle anti-roll moment M Frt_Comp and M Rr_Comp Go to step 5.

[0029] Step 5: According to the front and rear axle anti-roll moment M Frt_Comp and M Rr_Comp , combined with the front and rear wheelbase of the vehicle, the active suspension vertical control force F is converted FL 、F FR 、F RL 、F RR .

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1) Taking into account both the comfort and handling stability of the vehicle during cornering, a vehicle attitude feedforward-feedback control and a handling stability feedforward-feedback controller were designed. These two controllers are combined to achieve the goal of improving both the comfort and safety of the vehicle during cornering.

[0032] 2) Both the vehicle posture control and handling stability control adopt a feedforward-feedback control architecture, avoiding the problems of slow response and large overshoot when only feedback control is used, making the posture control and handling stability control more "natural" while also avoiding the problem of poor robustness to model parameter perturbations when only feedforward control is used.

[0033] 3) The body posture feedback control signal is derived from the fusion of the nonlinear vehicle model estimation signal and the measured signal. This not only prevents the body posture control from being affected by road input during vehicle steering, thereby improving system stability, but also saves four body height sensors, reducing system cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a system block diagram of the present invention.

[0035] Figure 2 It is a main step flow chart of the present invention.

[0036] Figure 3 It is a sub-step flow chart of main step 2 of the present invention.

[0037] Figure 4 It is a sub-step flow chart of main step 3 of the present invention.

[0038] Figure 5 It is a sub-step flow chart of main step 4 of the present invention. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the present application, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0040] like Figure 1 As shown, a vehicle steering posture and handling stability control method includes the following modules:

[0041] 1. Module 1 is a signal input module, which mainly provides the present invention with signals such as steering wheel angle, steering wheel speed, steering wheel torque, and vehicle speed;

[0042] 2. Module 2 is the vehicle body posture feedforward controller module, which is mainly used to calculate the vehicle's total anti-roll moment feedforward component.

[0043] 3. Module 3 is a nonlinear vehicle dynamics model, whose main function is to estimate the vehicle state, including but not limited to lateral acceleration, yaw angular velocity, rear axle slip angle, suspension dynamic travel and other signals. This module takes into account the main nonlinearities related to vehicle roll, such as suspension spring nonlinearity, suspension damping nonlinearity, tire nonlinearity, etc.

[0044] 4. Module 4 is the vehicle state fusion module, which mainly performs vehicle state fusion. Its input comes from the estimated signal of module 3 and part of the actual vehicle state signal.

[0045] 5. Module 5 is the vehicle body posture feedback controller, which is mainly used to calculate the total anti-roll moment feedback component of the vehicle.

[0046] 6. Module 6 is the handling stability feedforward controller, whose main function is to calculate the feedforward component of the front-to-rear distribution ratio of the vehicle's anti-roll moment.

[0047] 7. Module 7 is the handling stability feedback controller, whose main function is to calculate the feedback component of the front-to-rear distribution ratio of the vehicle's anti-roll moment.

[0048] 8. Module 8 is the control integration module, whose main function is to calculate the anti-roll moment of the front and rear axles of the vehicle and convert it into vertical control force instructions for each suspension angle.

[0049] 9. Module 9 represents a vehicle that is actually equipped with a fully active suspension.

[0050] 10. Single-cycle delay module.

[0051] 11. Single-cycle delay module.

[0052] 12. Single-cycle delay module.

[0053] The above modules are run according to certain steps. The main steps are as follows Figure 2 , see the sub-steps Figure 3 、 Figure 4 and Figure 5 , the steps are detailed as follows:

[0054] Step 1: Collect control-related vehicle signals, including but not limited to ① steering wheel angle, ② steering wheel angular velocity, ③ steering wheel input torque, and ④ vehicle speed.

[0055] Step 2: The vehicle posture feedforward-feedback controller calculates the total anti-roll moment M of the vehicle Tol , including M Tol_Comp 、M Tol_Norm 、M Tol_Spt etc., among which: ①M Tol_Comp Corresponding to a leisurely and comfortable driving style; ②M Tol_Nor Corresponding to daily driving style; ③M Tol_Spt This method is suitable for aggressive driving styles and mainly includes sub-steps 2-1 to 2-6.

[0056] In the present invention, M Comf The vehicle generates a negative roll angle of 0 to 3 degrees (can be calibrated on the actual vehicle) at any vehicle speed and any steering wheel angle in a steady state input to offset part of the lateral acceleration and improve ride comfort; Norm The vehicle can offset 50% to 95% of the roll angle (can be calibrated on the actual vehicle) at any vehicle speed and any steering wheel angle in a steady state, improving ride comfort while retaining a certain roll angle to help users perceive vehicle dynamics; Spt Make the vehicle as close to horizontal as possible under any speed and any steering wheel angle steady-state input to avoid body roll and the resulting changes in steering characteristics, while helping users gain a more stable driving field of view.

[0057] Sub-step 2-1, the vehicle posture feedforward controller receives signals such as steering wheel angle, angular velocity, steering torque and vehicle speed, and calculates the first anti-roll moment M Ff , including M Ff_Comf 、M Ff_Norm 、M Ff_Spt The calculation method can be a table lookup method or an online calculation method. The table lookup method obtains the optimal control quantity curve through offline simulation in advance and stores it in the software. The current control quantity is obtained by looking up the table through input signals such as steering wheel angle, angular velocity, vehicle speed, etc. The online calculation method can use feedforward controllers including but not limited to the following types G ff (s), the transfer function expression can be in the following forms:

[0058] ①G ff =K ff , this form focuses on feedforward steady-state compensation;

[0059] ② This form focuses on feedforward steady-state replenishment and delay compensation;

[0060] ③ This form focuses on calculating feedforward steady-state compensation and dynamic compensation;

[0061] ④ This form takes into account feedforward steady-state compensation, dynamic compensation and delay compensation.

[0062] Among them, K ff is the steady-state compensation gain, which can be obtained through experimental calibration or theoretical calculation. In theoretical calculation, its value is the ratio of the steady-state system input gain to the system noise gain; s is the Laplace operator; L ff is the system delay time, which can be obtained through experimental calibration or theoretical calculation. In theoretical calculation, its value is the difference between the system noise response delay and the system input response delay; T z 、T p The system input response time constant and the system noise response time constant can be obtained through experimental calibration or dynamic modeling analysis.

[0063] Sub-step 2-2, integrate the control variables of the vehicle posture feedforward controller and feedback controller to obtain the total anti-roll moment M of the vehicle Tol , including M Tol_Comp 、M Tol_Norm 、M Tol_Spt The control variables of the vehicle posture feedforward controller are derived from sub-step 2-1, and the control variables of the vehicle posture feedback controller are derived from sub-step 2-6 (to avoid an algebraic loop, the control variables need to be delayed by one cycle). Methods for synthesizing control variables include, but are not limited to: ① superposition; ② weighted summation.

[0064] Sub-step 2-3: Output the vehicle's total anti-roll moment M Tol , including M Tol_Comp 、M Tol_Norm 、M Tol_Spt , on the one hand it is output to step 4, on the other hand it is output to sub-steps 2-4.

[0065] Substeps 2-4 estimate the vehicle state based on a nonlinear vehicle dynamics model. The inputs of this nonlinear vehicle dynamics model are vehicle speed, steering wheel angle, and steering wheel speed, and the outputs include but are not limited to: ① lateral acceleration; ② yaw rate; ③ rear axle center of mass slip angle; ④ vehicle roll angle; ⑤ vehicle roll velocity; and ⑥ vehicle roll angle.

[0066] In the present invention, compared with conventional linear models, the nonlinear vehicle dynamics model takes into account the nonlinearity of the tire and the nonlinearity of the suspension. The nonlinearity of the tire is mainly reflected in the nonlinearity of the tire cornering stiffness with vertical load and longitudinal force, and the nonlinearity of the tire aligning torque with vertical load and longitudinal force. The nonlinearity of the suspension is mainly reflected in the nonlinearity of the spring stiffness, the nonlinearity of the suspension damping, the nonlinearity of the buffer block, and the nonlinearity of the suspension structure. These nonlinear effects are all separated from the linear model and updated by table lookup, which avoids the loss of accuracy caused by linearization and improves the overall estimation accuracy. Sub-steps 2-5 perform signal fusion based on the estimated vehicle state and the actual vehicle state measured by the sensor. The signal fusion method is as follows: when the vehicle is in a stable state, the calculation results of the nonlinear vehicle dynamics model are used; when the vehicle is in an unstable state, the actual measured signals of the on-board sensors are used; when the vehicle is between stable and unstable states, a fusion method including the Kalman filter method is used.

[0067] In the present invention, when the difference between the estimated yaw rate and the actual yaw rate is greater than a calibrated threshold value A1, or when the difference between the estimated center of mass sideslip angle and the actual center of mass roll angle is greater than a certain calibrated threshold value B1, the vehicle is considered to have entered an unstable state. When the difference in yaw rate is less than A2 and the difference in center of mass sideslip angle is less than B2, the vehicle is considered to have entered a stable state. At other times, the vehicle is considered to be between a stable and unstable state range.

[0068] Sub-step 2-6, based on the vehicle state after the signal fusion output from sub-step 2-5, feedback control is performed to calculate and output the anti-roll moment M Ff , including M Ff_Comp 、M Ff_Norm 、M Ff_Spt , the feedback control methods include but are not limited to: ① table lookup; ② proportional control; ③ PI control; ④ PD control; ⑤ PID control; ⑥ sliding mode control; ⑦ MPC control; ⑧ robust control.

[0069] Step 3: The handling stability feedforward-feedback controller calculates the front and rear axle anti-roll moment distribution ratio f, which includes but is not limited to: ① f suitable for a leisure and comfortable driving style Comf ; ② Suitable for daily driving style Norm ; ③ Suitable for aggressive driving style Spt . Mainly includes sub-steps 3-1 to 3-4.

[0070] In the present invention, f Comf Greater than the ratio of the front and rear roll stiffness of the vehicle without active suspension, f Conv , the vehicle tends to increase understeer, making it easier to control and less likely to drift; f Norm Approximately equal to f Conv, the vehicle maintains the steering characteristics of the conventional suspension, and the user is not easily aware of the control intervention; f Norm Less than f Conv , the vehicle tends to reduce understeer, making the vehicle's yaw gain greater, steering more sensitive, and cornering faster;

[0071] Sub-step 3-1, the handling stability feedforward controller receives signals such as steering wheel angle, angular velocity, steering torque and vehicle speed, and calculates the first front and rear axle anti-roll moment distribution ratio f, including: f Ff_Comf 、f Ff_Norm 、f Ff_Spt The calculation method can be a table lookup method or an online calculation method. The table lookup method obtains the optimal control quantity curve through offline simulation in advance and stores it in the software. The current control quantity is obtained by looking up the table through input signals such as steering wheel angle, angular velocity, vehicle speed, etc. The online calculation method can use feedforward controllers including but not limited to the following types G ff , the transfer function expression can be in the following forms:

[0072] ①G ff =K ff , this form focuses on feedforward steady-state compensation;

[0073] ② This form focuses on feedforward steady-state replenishment and delay compensation;

[0074] ③ This form focuses on calculating feedforward steady-state compensation and dynamic compensation;

[0075] ④ This form takes into account feedforward steady-state compensation, dynamic compensation and delay compensation.

[0076] Among them, K ff is the steady-state compensation gain, which can be obtained through experimental calibration or theoretical calculation. In theoretical calculation, its value is the ratio of the steady-state system input gain to the system noise gain; s is the Laplace operator; L ff is the system delay time, which can be obtained through experimental calibration or theoretical calculation. In theoretical calculation, its value is the difference between the system noise response delay and the system input response delay; T z 、T p The system input response time constant and the system noise response time constant can be obtained through experimental calibration or dynamic modeling analysis.

[0077] In sub-step 3-2, the handling stability feedback controller receives the measured vehicle yaw rate, lateral acceleration, rear axle center of mass slip angle and other signals, and calculates the second front and rear axle anti-roll moment distribution ratio f, including: f Fb_Comf 、f Fb_Norm 、f Fb_Spt, the feedback control methods include but are not limited to: ① table lookup; ② proportional control; ③ PI control; ④ PD control; ⑤ PID control; ⑥ sliding mode control; ⑦ MPC control; ⑧ robust control.

[0078] Sub-step 3-3, integrate the control variables of the handling stability feedforward controller and the feedback controller to obtain the front and rear axle anti-roll moment distribution ratio f, including: f Comf 、f Norm 、f Spt The control variables of the handling stability feedforward controller are derived from sub-step 3-1, and the control variables of the vehicle body posture feedback controller are derived from sub-step 3-2. Methods for integrating control variables include, but are not limited to: ① superposition; ② weighted summation.

[0079] Sub-steps 3-4, outputting the front and rear axle anti-roll moment distribution ratio f to step 4, include: f Comf 、f Norm 、f Spt .

[0080] Step 4, body posture control and handling stability control integration, this step receives the vehicle total anti-roll moment M calculated from step 2 Tol (including M Tol_Comp 、M Tol_Norm 、M Tol_Spt ) and the front and rear axle anti-roll moment distribution ratio f calculated in step 3 (including: f Comf 、f Norm 、f Spt ), combined with the actual state of the vehicle and the system state of the fully active suspension, the final front and rear axle anti-roll moment M is calculated Frt_Comp and M Rr_Comp The method mainly includes sub-steps 4-1 to 4-6. Sub-step 4-1: selection of the total anti-roll moment of the vehicle, output of the total anti-roll moment M of the vehicle Tol Select the appropriate vehicle total anti-roll moment M based on the current driving style evaluation results. Tol , the mapping relationship between driving style and total anti-roll moment should be defined by the OEM.

[0081] Sub-step 4-2: Compensate and correct the total anti-roll moment of the vehicle, and output the corrected total anti-roll moment M Tol_Comp . According to the current vehicle status and system status, the total anti-roll moment of the vehicle is compensated and corrected.

[0082] In the present invention, M Tol_Comp Compensation and correction include but are not limited to:

[0083] ① Correction based on the vehicle's available power limit: When the system power exceeds the vehicle's available power, the system output is torque-reduced according to the available power;

[0084] ② Correction based on the available power and torque of the motor: When the system power exceeds the available power of the active suspension motor,

[0085] Reduce the system output torque according to the available power: when the system torque limit exceeds the available torque of the active suspension motor, the output is based on the available torque value;

[0086] ③ Correction based on active suspension system fault status: When a serious fault occurs in the active suspension system, the system output torque is reduced to zero at a certain slope;

[0087] ④ Compensation based on the efficiency of the fully active suspension system: Based on the required torque and speed, the system efficiency is obtained by looking up the table, and the system input torque is obtained by inverse calculation based on the system efficiency;

[0088] ⑤ Compensation based on the nonlinearity of the fully active suspension structure: According to the table lookup, the transmission ratio of the fully active suspension is obtained (this value is generally not a constant and varies with the suspension travel), and the control force is compared to compensate;

[0089] ⑥ Compensation based on the inertia of the fully active suspension actuator: Based on the relative acceleration of the vehicle body and wheels, the rotational acceleration of the active suspension motor and other rotating components is calculated. Then, the inertial force is calculated based on the rotational inertia. Finally, an active force with an equal and opposite direction to the inertial force is applied to compensate for it.

[0090] Sub-step 4-3, selecting the front and rear axle anti-roll torque distribution ratio, outputs the front and rear axle anti-roll torque distribution ratio f. The appropriate front and rear axle anti-roll torque distribution ratio is selected based on the current driving style assessment results. The mapping relationship between driving style and total anti-roll torque should be defined by the OEM.

[0091] Sub-step 4-4, front and rear axle anti-roll moment distribution ratio f compensation correction, output compensation correction total anti-roll moment distribution ratio f Comp ; According to the current vehicle status and system status, the front and rear axle anti-roll moment distribution ratio f is compensated and corrected.

[0092] In the present invention, f Comp Correction compensation includes but is not limited to:

[0093] ① Adjust the front and rear axle anti-roll moment distribution ratio f based on external system requests.

[0094] Sub-steps 4-5: Calculate the front and rear axle anti-roll moment M Frt_Comp and M Rr_Comp :

[0095]

[0096] Sub-steps 4-6: Output the front and rear axle anti-roll moment M Frt_Comp and MRr_Comp Go to step 5.

[0097] Step 5: According to the front and rear axle anti-roll moment M Frt_Comp and M Rr_Comp , combined with the front and rear wheelbase of the vehicle, the active suspension vertical control force F is converted FL 、F FR 、F RL 、F RR , and finally sent to the fully active suspension actuator, including the left front, right front, left rear, and right rear corner fully active suspension actuators.

[0098] In the present invention, according to the front and rear axle anti-roll moment M Frt_Comp and M Rr_Comp Calculate the active suspension vertical control force F FL 、F FR 、F RL 、F RR , because M has been Frt_Comp and M Rr_Comp To make compensation, there is no need to repeatedly consider transmission ratio nonlinear compensation or rotational inertia compensation, and it can be calculated directly according to the front and rear wheel tracks.

[0099] The method of the present invention simultaneously optimizes vehicle posture and handling stability during steering, aiming to improve driver and passenger comfort and vehicle safety. First, the method calculates the total anti-roll torque using a vehicle posture feedforward-feedback controller. Outputting an appropriate anti-roll torque can reduce or eliminate steering roll, and can even generate a negative roll angle to offset centrifugal force, thereby improving driver and passenger comfort. Second, the front-to-rear axle distribution ratio of the anti-roll torque is calculated using a handling stability feedforward-feedback controller. This ratio influences the amount of wheel load transferred between the front and rear axles during steering, and thus the vehicle's steering characteristics. By controlling this ratio, the vehicle's understeer / oversteer characteristics can be dynamically adjusted in real time, thereby widening the vehicle's stability margins and improving driving safety and enjoyment. Finally, the method also considers the selection of feedback signals under different operating conditions, parameter selection to suit different driving styles, and compensation and correction of the anti-roll torque. This method exhibits excellent engineering feasibility and scalability, balancing vehicle comfort and handling stability. It is applicable to various types of fully active suspensions and active stabilizers, and has broad application prospects.

[0100] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for controlling vehicle steering posture and handling stability, characterized by: The following steps are involved: Step 1: Collect control-related vehicle signals, including steering wheel angle, angular velocity, steering torque, and vehicle speed; Step 2: The vehicle posture feedforward-feedback controller calculates the total anti-roll moment of the vehicle based on the steering wheel angle, angular velocity, steering torque and vehicle speed. M Tol ;specific include The vehicle body posture feedforward controller calculates the first anti-roll moment based on the steering wheel angle, angular velocity, steering torque and vehicle speed. M Ff The body posture feedback controller calculates the second anti-roll moment based on the fused vehicle state M Fb ; For the first anti-roll moment M Ff and the second anti-roll moment M Fb Variable integration to obtain the total anti-roll moment of the vehicle M Tol The fused vehicle state is obtained by estimating the vehicle state based on a nonlinear vehicle dynamics model, including yaw rate, sideslip angle, and lateral acceleration, and then fusing the estimated vehicle state with the actual vehicle state measured by the onboard sensors. Step 3: The handling stability feedforward-feedback controller calculates the front and rear axle anti-roll moment distribution ratio based on the steering wheel angle, angular velocity, steering torque and vehicle speed. f Specifically, the handling stability feedforward controller calculates the first front and rear axle anti-roll moment distribution ratio based on the steering wheel angle, angular velocity, steering torque and vehicle speed. f Ff The handling stability feedback controller calculates the second front and rear axle anti-roll moment distribution ratio based on the vehicle's yaw rate, lateral acceleration, and rear axle center of mass slip angle. f Fb ; Distribution ratio of anti-roll moment of the first front and rear axles f Ff and the second front and rear axle anti-roll moment distribution ratio f Fb Control variables are integrated to obtain the front and rear axle anti-roll moment distribution ratio f ; Step 4: Body posture control and handling stability control are integrated. Based on the actual state of the vehicle and the system state of the fully active suspension, the total anti-roll moment of the vehicle calculated in step 2 is calculated. M Tol And the front and rear axle anti-roll moment distribution ratio calculated in step 3 f Correction and compensation are performed to calculate the anti-roll moment of the front and rear axles M Frt_Comp and M Rr_Comp ; Step 5: According to the anti-roll moment of the front and rear axles M Frt_Comp and M Rr_Comp , the vertical force of the fully active suspension is calculated F FL 、 F FR 、 F RL 、 F RR , and output them to the left front, right front, left rear, and right rear corner full-active suspension actuators respectively.

2. The control method according to claim 1, wherein: The signal fusion method is that when the vehicle is in a stable state, the nonlinear vehicle dynamics model is used to calculate the results; when the vehicle is in an unstable state, the actual measured signals of the on-board sensors are used; when the vehicle is between stable and unstable states, a fusion method including the Kalman filter method is used.

3. The control method according to claim 1, wherein: The handling stability feedback controller subtracts the vehicle's measured signal from the target yaw rate and the target rear axle center of mass sideslip angle, and reduces the absolute value of the difference between the two through feedback control. Feedback control methods include table lookup, proportional control, PI control, PD control, PID control, sliding mode control, MPC control or robust control.

4. The control method according to claim 1, wherein: The feedforward control calculation method of the vehicle body posture feedforward controller and the handling stability feedforward controller adopts the table lookup method or the online calculation method. The table lookup method obtains the optimal control quantity curve through offline simulation in advance and stores it in the software. The current control quantity is obtained by looking up the table through the input signal; the online calculation method uses the feedforward controller G ff .

5. The control method according to claim 1, wherein: Step 4 includes, based on the current vehicle state and system state, calculating the total anti-roll moment of the vehicle M Tol Perform compensation correction to obtain the corrected total anti-roll moment M Tol_Comp , the anti-roll moment distribution ratio of the front and rear axles f Perform compensation correction to obtain the corrected total anti-roll moment distribution ratio f Comp ; According to the corrected total anti-roll moment M Tol_Comp and the corrected total anti-roll moment distribution ratio f Comp , calculate the anti-roll moment of the front and rear axles M Frt_Comp and M Rr_Comp .

6. The control method according to claim 5, characterized in that: Front and rear axle anti-roll moment M Frt_Comp and M Rr_Comp The calculation formula is, ； 。 7. The control method according to claim 5, characterized in that: Total anti-roll moment of the vehicle M Tol Factors that need to be considered when making compensation corrections include: vehicle power limit, active suspension power and torque limit, active suspension system fault status, full active suspension system efficiency compensation, full active suspension structure nonlinear compensation, and full active suspension system inertia compensation.

8. The control method according to claim 5, characterized in that: During compensation correction, the total anti-roll moment of the vehicle M Tol Selection and distribution ratio of front and rear axle anti-roll moment f Split ratio selection, which is chosen based on driver style.

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