An EPS angle control optimization method

Abstract

This invention relates to the field of steering system technology, specifically to an EPS angle control optimization method. The EPS angle control optimization method is as follows: S1, the motor torque calculation module calculates the rack torque T by obtaining the hand torque and motor torque from the sensor. r T r =T tbt *R1+T mot *R2; S2, the data acquisition module acquires the steering wheel angular velocity or wheel edge angular velocity signal dW a S3, the vehicle condition recognition module calculates the operating condition characteristic parameter P. f S4, Target angle W tar With the current angle W cur The difference is: ε = W tar -W cur S5, when P f Greater than threshold P f1 At that time, the angle control PID parameters are K p =P1,K i =I1,K d =D1;S6, when P f Less than threshold P f1 greater than the threshold P f2 At that time, the angle control PID parameters are K p =P2,K i =I2,K d =D2;S7, when P f Less than threshold P f2 At that time, the angle control PID parameters are K p =P3,K i =I3,K d =D3;S8, the torque of the assist motor is T mot =K p *ε+K i *∫ε+K d *dε; S9, the torque output by the actuator torque calculation module. Compared with existing technologies, this solves the problem of poor applicability of current PID angle control under various operating conditions.

Description

Technical Field

[0001] This invention relates to the field of steering system technology, specifically to an EPS angle control optimization method. Background Technology

[0002] Currently, driver assistance and autonomous driving technologies are being used more and more widely. Among them, the electric power steering system (EPS) is an important device for realizing the lateral control of a car, and the performance of EPS angle control directly affects the lateral control of a car in driver assistance or autonomous driving situations.

[0003] Current EPS angle control uses a PID algorithm, which calculates the target steering wheel angle and the actual steering wheel angle, and then performs PID calculations on both to obtain the power steering motor control torque. This control method performs well under normal driving conditions on cement or asphalt with a small slope. However, current assisted driving applications are becoming increasingly complex, and the operating conditions vary more greatly. Therefore, simply using fixed-parameter angle PID control cannot meet the needs of different scenarios. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides an EPS angle control optimization method that can solve the problem of poor applicability of current PID angle control under various operating conditions.

[0005] To achieve the above objectives, an EPS angle control optimization method is designed, including a data acquisition module, a vehicle condition recognition module, a control module, a motor torque calculation module, and an actuator. The specific optimization method is as follows:

[0006] S1, the motor torque calculation module calculates the rack torque by obtaining the hand force torque and the current motor torque through sensors. rack torque Equal to hand force torque Multiply by the steering wheel to rack transmission ratio In addition to the current motor torque Multiply by the motor-to-rack transmission ratio , ;

[0007] S2, the data acquisition module collects the steering wheel angular velocity or wheel edge angular velocity through the angle sensor. ;

[0008] S3, the vehicle condition recognition module calculates operating condition characteristic parameters based on rack torque and steering wheel angular velocity or wheel edge angular velocity. , t0 and t1 represent the beginning and end times of the computation cycle, respectively.

[0009] S4, Target Angle From the current perspective The difference is: ;

[0010] S5, when Greater than the threshold At that time, the angle control PID parameters are respectively ; This is the proportionality coefficient. The integral coefficient is... These are the differential coefficients;

[0011] S6, when Less than the threshold greater than the threshold At that time, the angle control PID parameters are respectively ; This is the proportionality coefficient. The integral coefficient is... These are the differential coefficients;

[0012] S7, when Less than the threshold At that time, the angle control PID parameters are respectively ; This is the proportionality coefficient. The integral coefficient is... These are the differential coefficients;

[0013] S8, calculate the target motor torque as follows ;

[0014] S9, the target motor torque output by the actuator motor torque calculation module is... .

[0015] The data acquisition module acquires steering wheel angular velocity or wheel edge angular velocity, driver's hand force, vehicle speed, camera, millimeter-wave radar, and ultrasonic radar.

[0016] The vehicle condition recognition module is used to calculate the characteristic parameters of vehicle driving conditions. And based on the threshold and Calculate the corresponding PID parameters , , .

[0017] The control module determines whether the EPS angle control function can be activated based on the driver's angle control selection, vehicle speed, driver's hand force, and steering wheel speed.

[0018] The motor torque calculation module calculates the target motor torque based on the EPS angle control activation state of the control module and the PID parameters calculated by the vehicle condition recognition module. .

[0019] The actuator is an EPS motor, and the target motor torque input to the motor torque calculation module is... .

[0020] Compared with existing technologies, this invention provides an EPS angle control optimization method that can solve the problem of poor applicability of current PID angle control under various operating conditions. It achieves good performance in EPS angle control under different vehicle speeds and road conditions, avoiding the inability to respond to the target angle due to performance tracking issues. Attached Figure Description

[0021] Figure 1 This is a diagram of the vehicle's lateral angle control system.

[0022] Figure 2 This is a reference diagram showing the characteristic parameters for steering conditions.

[0023] Figure 3 This is a reference performance diagram for angular response. Detailed Implementation

[0024] The present invention will now be further described with reference to the accompanying drawings.

[0025] An EPS angle control optimization method includes a data acquisition module, a vehicle condition recognition module, a control module, a motor torque calculation module, and an actuator. The specific optimization method is as follows:

[0026] S1, the motor torque calculation module calculates the rack torque by obtaining the hand force torque and the current motor torque through sensors. rack torque Equal to hand force torque Multiply by the steering wheel to rack transmission ratio In addition to the current motor torque Multiply by the motor-to-rack transmission ratio , ;

[0027] S2, the data acquisition module collects the steering wheel angular velocity or wheel edge angular velocity through the angle sensor. ;

[0028] S3, the vehicle condition recognition module calculates operating condition characteristic parameters based on rack torque and steering wheel angular velocity or wheel edge angular velocity. , t0 and t1 represent the beginning and end of the computation cycle, respectively. For example, if the computation cycle is 10ms, t0 represents the first 10ms, t1 represents the current cycle value, and the integral is the sum of data from every 1ms within these 10ms.

[0029] S4, Target Angle From the current perspective The difference is: ;

[0030] S5, when Greater than the threshold At that time, the angle control PID parameters are respectively ; This is the proportionality coefficient. The integral coefficient is... These are the differential coefficients;

[0031] S6, when Less than the threshold greater than the threshold At that time, the angle control PID parameters are respectively ; This is the proportionality coefficient. The integral coefficient is... These are the differential coefficients;

[0032] S7, when Less than the threshold At that time, the angle control PID parameters are respectively ; This is the proportionality coefficient. The integral coefficient is... These are the differential coefficients;

[0033] S8, calculate the target motor torque as follows ;

[0034] S9, the target motor torque output by the actuator motor torque calculation module is... .

[0035] The data acquisition module obtains steering wheel angular velocity or wheel edge angular velocity, driver's hand force, vehicle speed, camera, millimeter-wave radar and ultrasonic radar.

[0036] The vehicle condition recognition module is used to calculate the characteristic parameters of vehicle driving conditions. And based on the threshold and Calculate the corresponding PID parameters , , .

[0037] The control module determines whether the EPS angle control function can be activated based on the driver's angle control selection, vehicle speed, driver's hand force, and steering wheel speed.

[0038] The motor torque calculation module calculates the target motor torque based on the EPS angle control activation state of the control module and the PID parameters calculated by the vehicle condition recognition module. .

[0039] The actuator is an EPS motor, and the target motor torque is the input from the motor torque calculation module. . Specific Implementation

[0040] The overall vehicle angle lateral control system consists of the following components: Figure 1 As shown, it includes a camera, millimeter-wave radar, ultrasonic radar, ADS controller, vehicle speed sensor, steering wheel angle sensor, steering wheel force sensor, operating condition recognition system, EPS controller, and EPS steering motor.

[0041] When the driver activates adaptive cruise control or automatic parking via the instrument panel button or voice command, the ADAS controller collects information from the camera, radar, vehicle speed, steering wheel angle, and steering wheel force to determine whether to activate angle control. The determination conditions are as follows: the vehicle is more than 20cm away from the lane lines on both sides, the distance to the vehicle in front is 100m, the vehicle speed is less than 120km / h, the steering wheel force is less than 2Nm, and the steering wheel angle is less than 30°.

[0042] When the conditions are met, the ADAS controller activates the EPS angle control function and transmits the signal (Active state) to the EPS motor torque calculation module through the CAN network.

[0043] The vehicle condition recognition module calculates PID parameters suitable for the current operating conditions based on the steering wheel angle signal, steering wheel force signal, and EPS motor torque, and then transmits these parameters to the EPS motor torque calculation module. The vehicle condition recognition module first calculates the rack torque. The rack torque is equal to the hand torque. Multiply by the steering wheel to rack transmission ratio Plus motor torque Multiply by the motor-to-rack transmission ratio , Calculate steering characteristic parameters using current data. , .

[0044] like Figure 2 As shown, when the steering condition characteristic parameters Greater than threshold 1 (For example, at 2.5), this indicates that the vehicle's steering resistance is relatively high, and the high-resistance steering condition should be selected. , , Parameters that allow EPS performance to remain at Figure 3 Within the range shown.

[0045] when Less than the threshold (e.g., 2.5), greater than the threshold. (For example: 1) indicates that the vehicle's steering resistance is moderate. When turning on cement or asphalt roads, select the medium steering resistance setting. , , Parameters that allow EPS performance to remain at Figure 3 Within the range shown.

[0046] When steering condition characteristic parameters Less than threshold 2 (For example: 1) indicates that the vehicle's steering resistance is relatively low, and the low-resistance steering condition should be selected. , , Parameters that allow EPS performance to remain at Figure 3 Within the range shown.

[0047] The EPS motor torque calculation module calculates torque based on the target angle, the current angle, and the vehicle condition recognition module. , , The parameters are used to calculate the EPS motor torque using a PID algorithm.

[0048] The motor torque is calculated as follows: .

[0049] The torque output by the EPS motor torque calculation module.

[0050] EPS angle control performance should remain within a reasonable range under different operating conditions and environments. When the steering angular velocity is too high, i.e., the performance exceeds... Figure 3 A low minimum response curve can cause severe vehicle roll and pose a safety risk; when the steering angular velocity is too slow, i.e., the response is less than... Figure 3 A low Max Response curve will result in slow angle control response, failing to meet the needs of normal vehicle steering.

Claims

1. An EPS angle control optimization method, comprising a data acquisition module, a vehicle condition identification module, a control module, a motor torque calculation module, an actuator, characterized in that: The specific optimization methods are as follows: S1, the motor torque calculation module calculates the rack torque by obtaining the hand torque and the current motor torque through the sensor , The rack torque is equal to the hand torque times the steering wheel to rack ratio plus the current motor torque times the motor to rack ratio , ; S2, the data acquisition module collects the steering wheel angular velocity or wheel edge angular velocity through the angle sensor. ; S3, the vehicle condition recognition module calculates operating condition characteristic parameters based on rack torque and steering wheel angular velocity or wheel edge angular velocity. , t0 and t1 represent the beginning and end times of the computation cycle, respectively. S4, Target Angle From the current perspective The difference is: ; S5, when Greater than the threshold At that time, the angle control PID parameters are respectively ; This is the proportionality coefficient. The integral coefficient is... These are the differential coefficients; S6, when Less than the threshold greater than the threshold At that time, the angle control PID parameters are respectively ; This is the proportionality coefficient. The integral coefficient is... These are the differential coefficients; S7, when Less than the threshold At that time, the angle control PID parameters are respectively ; This is the proportionality coefficient. The integral coefficient is... These are the differential coefficients; S8, calculate the target motor torque as follows ; S9, the target motor torque output by the actuator motor torque calculation module is... .

2. The EPS angle control optimization method according to claim 1, characterized in that: The data acquisition module acquires steering wheel angular velocity or wheel edge angular velocity, driver's hand force, vehicle speed, camera, millimeter-wave radar, and ultrasonic radar.

3. The EPS angle control optimization method according to claim 1, characterized in that: The vehicle condition recognition module is used to calculate the characteristic parameters of vehicle driving conditions. And based on the threshold and Calculate the corresponding PID parameters , , .

4. The EPS angle control optimization method according to claim 1, characterized in that: The control module determines whether the EPS angle control function can be activated based on the driver's angle control selection, vehicle speed, driver's hand force, and steering wheel speed.

5. The EPS angle control optimization method according to claim 1, characterized in that: The motor torque calculation module calculates the target motor torque based on the EPS angle control activation state of the control module and the PID parameters calculated by the vehicle condition recognition module. .

6. The EPS angle control optimization method according to claim 1, characterized in that: The actuator is an EPS motor, and the target motor torque input to the motor torque calculation module is... .

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