Electric power steering system and control method

Abstract

The invention discloses an electric power steering system and a control method. The electric power steering system comprises a collector, a processor, a fuzzy PID controller and a motor, wherein the collector is used for collecting manual torque applied to a steering wheel and the current speed of the vehicle; the processor is connected with the collector for receiving the manual torque and the speed, acquiring expected target steering torque applying to the steering mechanism after the motor is power-on according to the manual torque, the speed and the preset steering control strategy, and further acquiring target current needed when the motor outputs the target steering torque; the fuzzy PID controller is connected with the output end of the processor for receiving the target current and the present current of the motor, adopting fuzzy PID control algorithm to adjust the output current of the fuzzy PID controller according to the target current and the present current of the motor until the present current is the same as the target current; and the motor is used for controlling the steering mechanism according to the output current of the fuzzy PID controller. Accuracy and stability of the electric power steering system are enhanced.

Description

technical field [0001] The invention relates to the field of automotive electronics, in particular, to an electric steering assist system and a control method. Background technique [0002] Electric Power Steering (EPS, Electric Power Steering) is a system that has become more and more popular in recent years. The system directly provides steering assistance by the electric motor. As a new steering technology, it saves energy and protects the environment compared with the traditional hydraulic steering system. It also has the characteristics of simple adjustment, flexible assembly, and can provide steering assistance under various conditions. . [0003] The working principle of the electric power steering system is as follows: first, the torque sensor measures the manual torque applied by the driver on the steering wheel, and the vehicle speed sensor measures the current driving speed of the vehicle, and then transmits these two signals to the controller; According to the ...

AI Technical Summary

Problems solved by technology

However, due to errors in the components and mechanical matching of the electric power steering system, the system cannot work accurately and stably in many cases, and even "overshoot" occurs

Especially when the car is running at high speed, the power assist is correspondingly reduced, and the reduction of the power assist has a large change, causing a large impact on the steering wheel, making it easy to cause the steering angle to oscillate when the steering returns to the right position, resulting in a "fluttering" feeling. feeling, affect the driver's control, and may even cause safety accidents

In addition, due to the loss of rotational torque caused by the frictional torque between the tire and the ground and the motor's own resistance torque, the accuracy and stability of the electric power steering system are not high.

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