Calibration method for steering angle control and computer readable storage medium

Abstract

The invention discloses a calibration method for steering angle control and a computer readable storage medium. The calibration method for steering angle control comprises the following steps: receiving vehicle driving condition parameters and vehicle configuration parameters; setting control parameters of a steering angle control algorithm; receiving an actual steering angle under the conditions of the vehicle driving condition parameters, the vehicle configuration parameters and the control parameters of the steering angle control algorithm; calculating a response parameter based on a comparison of the actual steering angle and the target steering angle; and judging whether the response parameter accords with a set value or not, and if yes, recording the control parameter of the steering angle control algorithm under the conditions of the vehicle driving working condition parameter and the vehicle configuration parameter as a qualified control parameter. According to the calibration method for steering angle control, calibration of the steering angle control algorithm can be realized.

Description

Technical Field

[0001] The present application relates to the automotive field, and in particular, to a calibration method for steering angle control and a computer-readable storage medium. Background Art

[0002] An electric steering system is provided in a car, and the electric steering system uses an electric motor to achieve the steering of the car. In automated driving, such as unmanned driving, a target steering angle is input to a steering machine controller, and the steering machine controller controls the operation of the electric motor to achieve the steering of the car, without the need for human intervention, such as the driver, in the process.

[0003] For example, when the driver assistance function is activated, the electric steering system uses the steering angle control algorithm to calculate the actual electric motor torque, and uses this electric motor torque to control the actual steering angle to keep it consistent with the target steering angle. The control parameters of the steering angle control algorithm play an important role in this process. Summary of the invention

[0004] The main technical problem to be solved by this application is how to calibrate the steering angle control algorithm.

[0005] In order to solve the above technical problems, on the one hand, the present application provides a calibration method for steering angle control, the calibration method comprising the following steps:

[0006] Receiving vehicle driving condition parameters and vehicle configuration parameters;

[0007] Set the control parameters of the steering angle control algorithm;

[0008] Receiving an actual steering angle under the vehicle driving condition parameters, vehicle configuration parameters and control parameters of a steering angle control algorithm;

[0009] Calculating a response parameter based on a comparison of the actual steering angle and the target steering angle;

[0010] It is determined whether the response parameter meets the set value. If so, the control parameter of the steering angle control algorithm under the vehicle driving condition parameter and the vehicle configuration parameter is recorded as a qualified control parameter.

[0011] On the other hand, the present application provides a computer-readable storage medium having a computer program stored thereon, which implements the steps of the aforementioned method when executed by a processor.

[0012] According to the technical solution of the present application, the response parameter is calculated based on the comparison between the actual steering angle and the target steering angle. If the response parameter meets the set value, it indicates that the control parameter of the set steering angle control algorithm is a qualified control parameter, thereby quickly judging whether the control parameter adopted under the vehicle driving condition parameters and vehicle configuration parameters can make the actual steering angle of the steering machine consistent with the target steering angle, thereby realizing the calibration of the steering angle control algorithm. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The disclosure of the present application is described with reference to the accompanying drawings. It should be understood that the drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present application. Among them:

[0014] Figure 1 The flowchart of the calibration method for steering angle control proposed in accordance with one embodiment of the present application is schematically shown. The symbols in the figure refer to the following:

[0015] A: Calibration environment configuration

[0016] B: Run the automatic calibration auxiliary program to obtain vehicle configuration information

[0017] C: Historical optimal parameter retrieval

[0018] D: The vehicle is moving at a constant speed

[0019] E: PID parameters are downloaded to the steering gear controller

[0020] F: Send target turning angle request to the steering machine

[0021] G: Obtain steering gear data and calculate control response parameters

[0022] H: Evaluation index evaluation and saving the optimal parameters

[0023] I: Angle iteration loop

[0024] J: End of iteration?

[0025] K: Vehicle speed iteration loop

[0026] L: End of iteration?

[0027] M: Are there any non-conforming items?

[0028] N: The vehicle is moving at a constant speed

[0029] O: Select inner loop PID and outer loop PID parameters

[0030] P: PID parameters are downloaded to the steering gear controller

[0031] Q: Send target angle request to the steering machine

[0032] R: Get steering gear data and calculate control response parameters

[0033] S: Evaluate the evaluation index and save the optimal parameters

[0034] T:PID parameter iteration loop

[0035] U: End of iteration?

[0036] V: Angle iteration loop

[0037] W: End of iteration?

[0038] X: Vehicle speed iteration loop

[0039] Y: End of iteration?

[0040] Z: The optimal PID parameters and vehicle configuration information combination data are saved in the vehicle calibration parameter database and uploaded to the cloud

[0041] AA: Optimal PID parameters exported to calibration report

[0042] C1: Matching success

[0043] C2: Matching failed

[0044] J1: Yes

[0045] J2: No

[0046] L1: Yes

[0047] L2: No

[0048] M1: Yes

[0049] M2: No

[0050] U1: Yes

[0051] U2:No

[0052] W1: Yes

[0053] W2:No

[0054] Y1: Yes

[0055] Y2: No. DETAILED DESCRIPTION

[0056] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. It will be appreciated by those skilled in the art that these descriptions are only illustrative and exemplary and should not be construed as limiting the scope of protection of the present application.

[0057] A calibration method for steering angle control according to a specific embodiment of the present application includes the following steps:

[0058] a) receiving vehicle driving condition parameters and vehicle configuration parameters, for example, through a data interaction module;

[0059] b) Setting the control parameters of the steering angle control algorithm;

[0060] c) receiving an actual steering angle under the vehicle driving condition parameters, vehicle configuration parameters and control parameters of the steering angle control algorithm; the actual steering angle is, for example, from a steering machine;

[0061] d) calculating a response parameter based on a comparison between the actual steering angle and the target steering angle;

[0062] e) Determine whether the response parameter meets the set value. If so, record the control parameter of the steering angle control algorithm under the vehicle driving condition parameters and vehicle configuration parameters as a qualified control parameter; if the response parameter does not meet the set value, no recording is required; the set value of the response parameter is determined in advance according to the required response performance, and the response parameter, as a steering angle control performance evaluation indicator, can be a numerical value or a numerical range.

[0063] The vehicle driving condition parameters include steering angle and / or vehicle speed. The vehicle configuration parameters include, for example, one or more of vehicle model, front axle load, front overhang type, and steering gear model.

[0064] The response parameters include one or more of rise time, overshoot angle, adjustment time and steady-state error. In the case where the response parameters include different variables, set values ​​can be set for each variable; in addition, the response parameters will meet the set values ​​only when each variable meets the set values.

[0065] Exemplarily, the steering angle control algorithm is a dual-loop PID control algorithm. The control parameters of the steering angle control algorithm include inner loop PID parameters and / or outer loop PID parameters. PID stands for proportional integral differential, the PID control algorithm is a proportional integral differential control algorithm, and the PID parameters are proportional integral differential parameters.

[0066] The inner loop PID parameters include the inner loop PID proportional coefficient k p1 、Inner loop PID integral coefficient k i1 、Inner loop PID differential coefficient k d1 And the maximum value k of the inner loop PID integral imax1 One or more of the outer loop PID parameters include the outer loop PID proportional coefficient k p2 、Outer loop PID integral coefficient k i2 、Outer loop PID differential coefficient k d2 And the maximum value k of the outer loop PID integralimax2 One or more of .

[0067] For example, when the SAE L2 driver assistance function is activated, the steering system uses a dual-loop PID control algorithm to calculate the actual electric motor torque, and uses the electric motor torque to control the actual steering angle to keep it consistent with the required steering angle. At this time, calibrating the dual-loop PID control algorithm is the main calibration work to achieve the correct performance response of the steering system under the L2 driver assistance function.

[0068] In the calibration method for steering angle control according to this embodiment, the response parameter is calculated based on the comparison between the actual steering angle and the target steering angle. If the response parameter meets the set value, it indicates that the control parameter of the set steering angle control algorithm is a qualified control parameter, thereby quickly judging whether the control parameter under the vehicle driving condition parameters and vehicle configuration parameters can make the actual steering angle of the steering machine consistent with the target steering angle, thereby realizing the calibration of the steering angle control algorithm.

[0069] Further, in step b), the control parameters of the steering angle control algorithm are traversed from the minimum value to the maximum value with a certain step length (e.g., 0.01), and after step e), the response parameters corresponding to the qualified control parameters are recorded. In this way, by traversing the control parameters of the steering angle control algorithm, all qualified control parameters are found. The method can be automated to quickly find qualified control parameters.

[0070] On this basis, if more than two qualified control parameters are found, the response parameters corresponding to different control parameters can be compared, the control parameters corresponding to the better response parameters can be retained, and the control parameters corresponding to the worse response parameters can be deleted. For example, all response parameters can be directly compared, and the control parameters corresponding to the best response parameters can be selected. For example, two adjacent response parameters can also be compared, and the control parameters corresponding to the better response parameters can be retained, and finally only the control parameters corresponding to the best response parameters can be retained.

[0071] In the case where the response parameter includes different variables, each variable can be assigned a weight, so as to calculate the value of the response parameter as a whole and compare the advantages and disadvantages of different response parameters. In addition, the weight of each variable can be changed as needed.

[0072] For different vehicle driving condition parameters, the control parameters of the steering angle control algorithm can be traversed respectively and qualified control parameters can be recorded. In the case where the vehicle driving condition parameters include steering angle and vehicle speed, each steering angle (for example, from -1000 degrees to +1000 degrees) can be traversed first, and then each vehicle speed (for example, from 0-100kph) can be traversed.

[0073] Further, after step a), it is checked whether there are qualified control parameters under the vehicle driving condition parameters and vehicle configuration parameters. If so, the process jumps to step c); then in step e), if the response parameter does not meet the set value, the process jumps to step b). In this way, for the case where the qualified control parameters have been calibrated or stored, it is possible to quickly check whether the control parameters meet the requirements.

[0074] According to a specific embodiment of the present application, a calibration method for steering angle control is exemplarily as follows: Figure 1 The specific steps are as follows:

[0075] 1. Configure the calibration environment, connect the computer and the controller through the calibration tool, and ensure normal communication.

[0076] 2. Run the automatic calibration auxiliary program, the program will obtain the vehicle configuration information, and automatically retrieve the matching calibration from the cloud and local vehicle calibration parameter database through the vehicle configuration information. If the match is successful, the calibration parameters are obtained and downloaded to the steering controller. All calibration speeds and calibration angles are traversed, and the current calibration parameters are determined by comparing the response parameters. At this time, iterative optimization is not activated (such as Figure 1 left half).

[0077] 3. If the result of step 2 shows that the parameters are not qualified, iterative optimization is activated (such as Figure 1 As shown in the right half), the PID parameter iteration optimization program is executed: because the steering gear load is strongly related to the vehicle speed and steering angle, it is necessary to perform parameter iteration according to different vehicle speeds and steering angles. Therefore, the iterative optimization includes three parts: PID parameter iteration, angle iteration, and vehicle speed iteration. Specifically:

[0078] S1: Keep the vehicle moving at a constant speed, the initial speed is 0kph

[0079] S2: Select inner and outer loop PID parameters

[0080] S3: Download the PID parameters to the steering gear controller through the calibration tool

[0081] S4: Send a request for the target turning angle to the steering gear through the computer

[0082] S5: Get the actual turning angle sent by the steering gear, calculate the control response parameter, and then compare the evaluation standard value defined by the response parameter. If the response parameter meets the evaluation standard value and is better than the previous response parameter, save the parameter, otherwise discard the parameter

[0083] S6: PID parameter iteration loop: repeat steps S2-S5, where the change step size of the inner and outer loop PID parameters in each loop step S2 is 0.01, and the traversal is completed from 0 to the maximum value, and all parameter combinations are traversed. After this loop is completed, the optimal PID parameters under constant vehicle speed and constant angle will be obtained, and the obtained optimal PID parameters will be combined with the vehicle speed and angle information and saved.

[0084] S7: Angle iteration loop: repeat steps S4-S6, where the target angle sent in step S4 changes in steps of 50 degrees each time (the step length is adjustable), and the angle change needs to include two directions: first increase from 0 to the maximum value, then decrease from the maximum value to the negative maximum value, and then increase from the negative maximum value to 0. After this cycle is completed, the optimal PID parameters of all calibrated angles at a constant vehicle speed will be obtained, and the obtained optimal PID parameters will be combined with the vehicle speed information and saved.

[0085] S8: Speed ​​iteration loop: repeat steps S1-S7, where the speed change step size in each loop step S1 is 20kph (the step size is adjustable), and the maximum speed is 100kph. After this loop is completed, the optimal PID parameters for all calibrated speeds and all calibrated angles will be obtained, and the obtained optimal PID parameters will be combined with the vehicle configuration information and saved.

[0086] S9: The optimal PID parameters of the angle control function and the vehicle configuration information are combined and saved in the vehicle calibration parameter database, uploaded to the cloud, and the optimal PID parameters are output to the calibration report file.

[0087] The present application also includes a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the steps of the method described in any one or more of the aforementioned embodiments are implemented. The technical features and technical effects possessed by the computer program therefore correspond to the previous description and will not be repeated here.

Claims

1. A calibration method for steering angle control, characterized in that: The calibration method comprises the following steps: Receiving vehicle driving condition parameters and vehicle configuration parameters; Set the control parameters of the steering angle control algorithm; Receiving an actual steering angle under the vehicle driving condition parameters, vehicle configuration parameters and control parameters of a steering angle control algorithm; Calculating a response parameter based on a comparison of the actual steering angle and the target steering angle; It is determined whether the response parameter meets the set value. If so, the control parameter of the steering angle control algorithm under the vehicle driving condition parameter and the vehicle configuration parameter is recorded as a qualified control parameter.

2. The calibration method for steering angle control according to claim 1, characterized in that: The vehicle driving condition parameters include steering angle and / or vehicle speed, and the vehicle configuration parameters include one or more of vehicle model, front axle load, front suspension type and steering gear model.

3. The calibration method for steering angle control according to claim 1, characterized in that: The response parameters include one or more of rise time, overshoot angle, adjustment time and steady-state error.

4. The calibration method for steering angle control according to claim 1, characterized in that: The steering angle control algorithm is a dual-loop proportional-integral-differential control algorithm, and control parameters of the steering angle control algorithm include inner-loop proportional-integral-differential parameters and / or outer-loop proportional-integral-differential parameters.

5. The calibration method for steering angle control according to claim 4, characterized in that: The inner loop proportional-integral-differential parameters include one or more of an inner loop proportional coefficient, an inner loop integral coefficient, an inner loop differential coefficient, and an inner loop integral maximum value; the outer loop proportional-integral-differential parameters include one or more of an outer loop proportional coefficient, an outer loop integral coefficient, an outer loop differential coefficient, and an outer loop integral maximum value.

6. The calibration method for steering angle control according to claim 1, characterized in that: In setting the control parameters of the steering angle control algorithm, the control parameters of the steering angle control algorithm are traversed from the minimum value to the maximum value with a certain step size, and after determining that the response parameters meet the set values, the response parameters corresponding to the qualified control parameters are recorded.

7. The calibration method for steering angle control according to claim 6, characterized in that: Compare the response parameters corresponding to different control parameters, and retain the control parameters corresponding to the better response parameters.

8. The calibration method for steering angle control according to claim 6, characterized in that: For different vehicle driving condition parameters, the control parameters of the steering angle control algorithm are traversed respectively and the qualified control parameters are recorded.

9. The calibration method for steering angle control according to claim 1, characterized in that: After receiving the vehicle driving condition parameters and the vehicle configuration parameters, find out whether there are qualified control parameters under the vehicle driving condition parameters and the vehicle configuration parameters, and if so, receive the actual steering angle; then If the response parameter does not meet the set value, the control parameter of the steering angle control algorithm is set.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 9 are implemented.

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