EPS automatic parking optimization control method
The motor torque output is optimized through the data acquisition and control module, and the performance limitation of the EPS automatic parking function when the motor is overheated is solved, the motor temperature and performance balance is achieved, preventing function exit and hardware damage, and extending the motor life.
Patent Information
- Application Number
- CN202510450012.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-11
- Publication Date
- 2025-07-08
AI Technical Summary
Under long-term high angle and high torque conditions, the EPS automatic parking function is withdrawn due to overheating of the motor, resulting in limited performance, and even hardware damage or reduced life.
Relevant information is obtained through the data acquisition module, the steady-state error control module is used to calculate the maximum steady-state error, and combined with the motor torque thermal balance control module and the automatic parking angle follow control module, the motor torque output is optimized, ensuring the motor temperature and performance balance, and preventing overheating.
When the motor is overheated, ensure the normal operation of the automatic parking function, prevent function exit and hardware damage, and extend the motor life.
Smart Images
Figure CN120270327A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of steering systems, and more specifically, to an EPS automatic parking optimization control method. Background Art
[0002] Currently, assisted driving technologies have been maturely applied in the market, and the automatic parking function is also configured in more and more vehicle models. Facing the increasingly complex parking usage scenarios, higher performance requirements are often needed for the automatic parking function. In the application of long-time large-angle and large-torque working conditions, the EPS will reduce the steering control torque due to stalling or high temperature, which also causes the automatic parking function to exit. Summary of the Invention
[0003] The present invention aims to overcome the deficiencies of the prior art and provides an EPS automatic parking optimization control method, which can solve the problem of poor applicability under current over-temperature working conditions.
[0004] To achieve the above object, an EPS automatic parking optimization control method is designed, including a data acquisition module, a steady-state error control module, a motor torque thermal balance control module, and an automatic parking angle following control module. The specific optimization control method is as follows:
[0005] (1) The data acquisition module obtains the steering wheel angle, steering wheel angular velocity, and motor temperature information.
[0006] (2) The steady-state error control module calculates the maximum steady-state error according to the motor temperature, and the maximum steady-state error is obtained by interpolation calculation based on the current motor temperature.
[0007] (3) The automatic parking angle following control module calculates the torque according to the parking target angle.
[0008] (4) The motor torque thermal balance control module obtains the maximum motor output torque according to the motor temperature and the maximum steady-state error.
[0009] (5) The actuator of the EPS is the EPS motor, and the motor torque thermal balance control module takes the maximum motor output torque obtained in step (4) as the target motor torque.
[0010] In the above step (2), the motor temperature estimation method adopts the resistance temperature coefficient estimation method, and the calculation formula is where T is the current temperature; T0 is the reference temperature; R0 is the resistance at the reference temperature; R is the current resistance; and α is the temperature coefficient.
[0011] In the above step (3), the torque calculation is implemented by the PID algorithm, and the calculation formula is where T mFor motor control torque; Δw is the difference between the target angle and the current angle; K p Proportional gain; K i Integral gain; K d Derivative gain.
[0012] In the said step (4), the calculation formula for the motor output torque is Where, V q Is the Q-axis voltage; i q Is the Q-axis current; ω is the electrical angular velocity of the motor; L d Is the D-axis inductance; i d Is the D-axis current; λ is the magnetic flux of the permanent magnet.
[0013] The temperature collected by the said data acquisition module is one or more of the motor temperature, PCB temperature, MOS temperature, MCU temperature, and ECU temperature.
[0014] The angle collected by the said data acquisition module is one or more of the steering wheel angle, EPS motor angle, and rack position.
[0015] The angular velocity collected by the said data acquisition module is one or more of the steering wheel angular velocity, motor speed, and rack speed.
[0016] Compared with the prior art, the present invention provides an EPS automatic parking optimization control method, which can ensure the balance between the motor temperature and the following performance in the case of motor overheating, prevent the function from exiting due to motor overheating, and at the same time prevent hardware damage or reduced life due to long-term motor overheating. Brief Description of the Drawings
[0017] Figure 1 Is the flow chart of the present invention.
[0018] Figure 2 Is the relationship diagram between the EPS stall torque and the angle.
[0019] Figure 3 Is the steady-state error calculation diagram.
[0020] Figure 4 Is the torque gradient diagram. Detailed Embodiment
[0021] The following further describes the present invention with reference to the drawings.
[0022] As Figure 1 Shown, the method of the present invention includes: a data acquisition module, a steady-state error control module, a motor torque thermal balance control module, and an automatic parking angle following control module; obtaining the motor temperature C through a sensor mot , steering wheel angle w SAS , steering wheel angular velocity vSAS 。
[0023] After the temperature exceeds the limit, reduce the steady-state angular error under the locked-rotor condition, and limit the control torque of the automatic parking function to achieve the thermal balance of the motor temperature.
[0024] The specific optimization control method is as follows:
[0025] (1) The data acquisition module obtains the steering wheel angle, steering wheel angular velocity, and motor temperature information;
[0026] (2) The steady-state error control module estimates the maximum steady-state error according to the motor temperature, and the error can be obtained by interpolating the current motor temperature;
[0027] (3) The automatic parking angle following control module calculates the control torque according to the parking target angle, and this calculation can be implemented by the PID algorithm or other methods: Among them, T m is the motor control torque; Δw is the difference between the target angle and the current angle; K p is the proportional gain; K i is the integral gain; K d is the derivative gain;
[0028] (4) The motor torque thermal balance control module controls the maximum motor output torque according to the temperature and the maximum steady-state error. This part realizes the thermal balance control of the torque by estimating the current motor temperature. The motor temperature estimation method can adopt the resistance temperature coefficient estimation method or other motor temperature estimation methods: Among them, T is the current temperature; T0 is the reference temperature; R0 is the resistance at the reference temperature; R is the current resistance; α is the temperature coefficient;
[0029] (5) Obtain Among them, V q is the Q-axis voltage; i q is the Q-axis current; ω is the electrical angular velocity of the motor; L d is the D-axis inductance; i d is the D-axis current; λ is the magnetic flux of the permanent magnet;
[0030] (6) The actuator is the EPS motor, and the input of the motor torque thermal balance control module is the target motor torque.
[0031] Under the condition of motor overheating, ensure that the automatic parking function can achieve the balance between the motor temperature and the following performance, prevent the function from exiting due to motor overheating, and at the same time, long-term motor overheating will cause hardware damage or reduced life. Specific embodiments:
[0033] When the EPS receives the angle control instruction sent by the ADAS controller, the automatic parking angle following control module controls the motor torque output by using methods such as PID or difference calculation according to the target control angle and the current angle to achieve angle following control. When the EPS maintains at the end of the stroke, a relatively large motor torque is required at this time to balance the resilience of the vehicle chassis, such as Figure 2 shown. When the motor is in the high-torque stall condition, it will cause the temperature to rise rapidly. When the temperature exceeds the critical temperature (for example, 180 °C), the EPS system takes the way of reducing the boost to prevent the motor from overheating, but the automatic parking function exits due to performance limitations or inability to follow the angle.
[0034] When the EPS operates normally, the energy is converted from electrical energy into mechanical energy of the motor rotation, and the motor generates less heat. When the EPS is in the stall condition, if the stall torque is large, the energy is converted from electrical energy into motor heat energy. Therefore, the probability of the motor overheating is relatively high.
[0035] The present invention optimizes the parking function for the stall condition at high temperature to prevent the automatic parking function from exiting due to motor overheating.
[0036] When the motor temperature exceeds the control threshold Tem lim (160 °C), the steady-state error control module estimates the maximum steady-state error according to the current temperature. For example, when the temperature is 170 °C, the steady-state error is 3 °, as Figure 3 shown. That is, when the target angle is 500 °, the control angle range is [497 °, 503 °].
[0037] After the motor torque thermal balance control module detects that the motor temperature exceeds the control threshold Tem lim (160 °C), it interpolates and calculates the torque target decrease gradient T gra , as Figure 4 shown. For example, when the temperature is 170 °C, the calculated target torque change gradient T gra = 0.12 Nm / s.
[0038] The motor torque thermal balance control module monitors and calculates the temperature change and the steering wheel angle change in real time. For example, when the temperature change gradient is less than 0 every 100 ms or the current angle exceeds the control angle range, the target torque change gradient is set to T gra = 0 Nm / s.
[0039] When the torque calculated by the automatic parking angle following control module is greater than the threshold T lim (1.5 Nm), and the steering wheel angular velocity is less than the threshold v lim (1 ° / s) for a duration t lim (500 ms), the motor torque thermal balance control module controls the automatic parking torque to decrease at the target torque change gradient.
[0040] In the present invention, the motor temperature can also be replaced by other temperatures of the EPS, such as the PCB temperature, the MOS temperature, the MCU temperature, the ECU temperature, etc.; the steering wheel angle can be replaced by the EPS motor angle, the rack position, etc.; the steering wheel angular velocity can be replaced by the motor speed, the rack speed, etc.
Claims
1. An EPS automatic parking optimization control method, comprising a data acquisition module, a steady-state error control module, a motor torque thermal balance control module, and an automatic parking angle following control module, characterized in that, The specific optimization control method is as follows: (1) The data acquisition module obtains the steering wheel angle, steering wheel angular velocity, and motor temperature information; (2) The steady-state error control module calculates the maximum steady-state error based on the motor temperature, and the maximum steady-state error is obtained through interpolation according to the current motor temperature; (3) The automatic parking angle following control module calculates the torque according to the parking target angle; (4) The motor torque thermal balance control module obtains the maximum motor output torque based on the motor temperature and the maximum steady-state error; (5) The actuator of the EPS is the EPS motor, and the motor torque thermal balance control module uses the maximum motor output torque obtained in step (4) as the target motor torque.
2. The EPS automatic parking optimization control method according to claim 1, characterized in that: In the said step (2), the motor temperature estimation method adopts the resistance temperature coefficient estimation method, and the calculation formula is wherein, T is the current temperature; T0 is the reference temperature; R0 is the resistance at the reference temperature; R is the current resistance; and α is the temperature coefficient.
3. An EPS automatic parking optimization control method according to claim 1, characterized in that: In the said step (3), the torque calculation is implemented by the PID algorithm, and the calculation formula is where T m is the motor control torque; Δw is the difference between the target angle and the current angle; K p is the proportional gain; K i is the integral gain; K d is the derivative gain.
4. An EPS automatic parking optimization control method according to claim 1, characterized in that: In the said step (4), the calculation formula for the motor output torque is where V q is the Q-axis voltage; i q is the Q-axis current; ω is the electrical angular velocity of the motor; L d is the D-axis inductance; i d is the D-axis current; λ is the magnetic flux linkage of the permanent magnet.
5. An EPS automatic parking optimization control method according to claim 1, characterized in that: The temperature collected by the data acquisition module is one or more of the motor temperature, PCB temperature, MOS temperature, MCU temperature, and ECU temperature.
6. The EPS automatic parking optimization control method according to claim 1, wherein: The angle collected by the data acquisition module is one or more of the steering wheel angle, EPS motor angle, and rack position.
7. An EPS automatic parking optimization control method according to claim 1, characterized in that: The angular velocity collected by the data acquisition module is one or more of the steering wheel angular velocity, motor speed, and rack speed.