CN-121608801-B - Low-temperature friction compensation method and system for electric power steering system

CN121608801BCN 121608801 BCN121608801 BCN 121608801BCN-121608801-B

Abstract

A low-temperature friction compensation method and system for an electric power steering system comprise the steps of obtaining PCB temperature-sensitive resistor voltage in a controller of the electric power steering system when a vehicle is electrified, controlling a motor of the electric power steering system to output a detection signal, collecting starting current of the motor under the detection signal, determining estimated initial temperature of a steering column of the electric power steering system based on the PCB temperature-sensitive resistor voltage, the starting current and a preset off-line three-dimensional mapping table, further determining basic compensation torque of the electric power steering system, determining real-time compensation torque of the electric power steering system in the operation process, and performing torque compensation processing. According to the application, the estimated initial temperature of the steering column is accurately calculated through the PCB temperature-sensitive resistor voltage and the starting current of the motor under the detection signal, so that the low-temperature friction compensation is more accurate, and the hardware such as a temperature sensor and the like is not required to be additionally added, thereby avoiding the increase of hardware cost and assembly complexity.

Inventors

ZHANG XINDA
Mao Yikun
LUO CHUNSHENG

Assignees

英诺菲特(北京)科技有限公司

Dates

Publication Date: 20260512
Application Date: 20251215

Claims (10)

1. The low-temperature friction compensation method of the electric power steering system is characterized by comprising the following steps of: when the vehicle is electrified, the PCB temperature-sensitive resistor voltage in the controller of the electric power steering system is obtained; Controlling a motor of the electric power steering system to output a detection signal, and collecting starting current of the motor under the detection signal; Determining an estimated initial temperature of a steering column of the electric power steering system based on the PCB temperature-sensitive resistor voltage, the starting current and a preset off-line three-dimensional mapping table, wherein the off-line three-dimensional mapping table comprises a corresponding relation among the PCB temperature-sensitive resistor voltage, the starting current and the actual temperature of the steering column; determining a base compensation torque of the electric power steering system according to the estimated initial temperature; Determining a real-time compensation torque of the electric power steering system in the running process based on the basic compensation torque; And performing torque compensation processing according to the real-time compensation torque.
2. The method for low-temperature friction compensation of an electric power steering system according to claim 1, wherein before determining the estimated initial temperature of a steering column of the electric power steering system based on the PCB temperature-sensitive resistor voltage, the starting current, and a preset off-line three-dimensional map, further comprises: in the low-temperature environment cabin, sequentially controlling the environment temperature to a plurality of preset low-temperature points; recording the value of the temperature-sensitive resistor voltage of the PCB at each low-temperature point; Measuring peak current of the motor under a preset starting condition at each low-temperature point; measuring the actual temperature of the steering column at each of said cryogenic temperature points using a touch sensor; And generating a value of the PCB temperature-sensitive resistor voltage and a mapping relation between the peak current and the actual temperature to obtain the off-line three-dimensional mapping table.
3. The method of low temperature friction compensation of an electric power steering system of claim 1, wherein determining a real-time compensation torque of the electric power steering system during operation based on the base compensation torque comprises: Determining a temperature rise value of the steering column relative to the estimated initial temperature based on a PCB temperature-sensitive resistor voltage and a working current of the motor in the operation process of the electric power steering system; determining a friction compensation attenuation amount based on the temperature rise value; And correcting the basic compensation torque by utilizing the friction compensation attenuation amount to obtain the real-time compensation torque.
4. A low temperature friction compensation method of an electric power steering system according to claim 3, wherein said determining a friction compensation attenuation amount based on said temperature rise value includes: acquiring a preset temperature rise attenuation coefficient; and determining the friction compensation attenuation amount based on the product of the temperature rise value and the temperature rise attenuation coefficient.
5. The method for compensating low-temperature friction of an electric power steering system according to claim 1, wherein said performing a torque compensation process according to said real-time compensation torque includes: acquiring a hand force torque signal applied to a steering wheel; determining a base boost torque based on the hand torque signal; and triggering a torque compensation command comprising the sum of the basic assistance torque and the real-time compensation torque to perform the torque compensation processing.
6. The method of low-temperature friction compensation of an electric power steering system according to claim 5, wherein the triggering includes a torque compensation command of a sum of the basic assist torque and the real-time compensation torque, before performing the torque compensation process, further comprising: determining that the real-time compensation torque is greater than zero; the low-temperature friction compensation method of the electric power steering system further comprises the following steps: and if the real-time compensation torque is smaller than or equal to zero, triggering a torque compensation command comprising the basic power-assisted torque so as to perform the torque compensation processing.
7. The method for compensating for low temperature friction of an electric power steering system according to claim 1, wherein after the step of obtaining the temperature-sensitive resistor voltage of the PCB inside the controller of the electric power steering system, further comprises: judging whether the voltage of the PCB temperature-sensitive resistor is lower than a preset low-temperature judging threshold value or not; And if the voltage of the PCB temperature-sensitive resistor is smaller than the low-temperature judging threshold value, executing the step of controlling the motor of the electric power steering system to output a detection signal.
8. The method for low temperature friction compensation of an electric power steering system according to claim 1, wherein the controlling the motor of the electric power steering system to output a detection signal and collecting a starting current of the motor under the detection signal comprises: Controlling the motor to perform steering drive treatment of a steering column with a preset small angle; acquiring an instantaneous load current of the motor when steering drive processing of a steering column with a preset small angle is performed; a starting current is determined based on the instantaneous load current.
9. The method of low temperature friction compensation of an electric power steering system according to claim 1, wherein said determining a base compensation torque of said electric power steering system based on said estimated initial temperature comprises: Acquiring a preset temperature-compensation torque correlation table, wherein the correlation table comprises compensation torque reference values required for overcoming static friction force at different mechanical temperatures; and searching a corresponding compensation torque reference value in the temperature-compensation torque association table based on the estimated initial temperature, and taking the compensation torque reference value as the basic compensation torque.
10. A low-temperature friction compensation system of an electric power steering system, characterized in that the low-temperature friction compensation system of an electric power steering system is used to perform the low-temperature friction compensation method of an electric power steering system according to any one of claims 1 to 9.

Description

Low-temperature friction compensation method and system for electric power steering system Technical Field The application relates to the technical field of automobile electronic control, in particular to a low-temperature friction compensation method and system of an electric power steering system. Background In an extremely low temperature environment, lubricating grease in kinematic pairs such as a pipe column and a gear of the electric power steering system (Electric Power Steering and EPS) can become sticky, and meanwhile, small expansion and contraction of metal materials can cause the change of fit clearances, so that the static friction and the dynamic friction of the system are obviously increased under the combined action. This results in the driver experiencing excessive steering effort during cold start of the vehicle at low temperatures, severely affecting driving experience and safety. In the related art, an additional temperature sensor may be added to directly measure the column temperature and then low temperature friction compensation is performed according to the directly measured column temperature, but this approach may result in an increase in hardware cost and assembly complexity. Disclosure of Invention The application provides a low-temperature friction compensation method and a low-temperature friction compensation system for an electric power steering system, aiming at avoiding the increase of hardware cost and assembly complexity when low-temperature friction compensation is carried out. In a first aspect, the present application provides a low temperature friction compensation method of an electric power steering system, the low temperature friction compensation method of the electric power steering system comprising: when the vehicle is electrified, the PCB temperature-sensitive resistor voltage in the controller of the electric power steering system is obtained; Controlling a motor of the electric power steering system to output a detection signal, and collecting starting current of the motor under the detection signal; Determining an estimated initial temperature of a steering column of the electric power steering system based on the PCB temperature-sensitive resistor voltage, the starting current and a preset off-line three-dimensional mapping table, wherein the off-line three-dimensional mapping table comprises a corresponding relation among the PCB temperature-sensitive resistor voltage, the starting current and the actual temperature of the steering column; determining a base compensation torque of the electric power steering system according to the estimated initial temperature; Determining a real-time compensation torque of the electric power steering system in the running process based on the basic compensation torque; And performing torque compensation processing according to the real-time compensation torque. In the embodiment, the estimated initial temperature of the steering column is accurately calculated through the PCB temperature-sensitive resistor voltage and the starting current of the motor under the detection signal, so that the low-temperature friction compensation is more accurate, and hardware such as a temperature sensor and the like is not required to be additionally added, thereby avoiding the increase of hardware cost and assembly complexity. In some embodiments, before determining the estimated initial temperature of the steering column of the electric power steering system based on the PCB temperature-sensitive resistance voltage, the starting current, and the preset offline three-dimensional map, the method further includes: in the low-temperature environment cabin, sequentially controlling the environment temperature to a plurality of preset low-temperature points; recording the value of the temperature-sensitive resistor voltage of the PCB at each low-temperature point; Measuring peak current of the motor under a preset starting condition at each low-temperature point; measuring the actual temperature of the steering column at each of said cryogenic temperature points using a touch sensor; And generating a value of the PCB temperature-sensitive resistor voltage and a mapping relation between the peak current and the actual temperature to obtain the off-line three-dimensional mapping table. In the embodiment, a high-precision correlation model comprising environmental thermal parameters, mechanical damping characteristics and real physical temperature is constructed through an off-line calibration process, and low-temperature friction characteristics which are difficult to quantify are converted into a data mapping table which can be represented by electronic signals by utilizing true value measurement in a laboratory environment, so that a reliable data reference is provided for temperature estimation in actual operation. In some embodiments, the determining the real-time compensation torque of the electric power steering system during operation