Vehicle steering systems can be divided into mechanical steering systems and power steering systems based on the energy of steering.

The mechanical steering system relies on the steering force of the driver to steer the steering wheel to realize the steering of the wheel; the power steering system controls the steering of the wheel under the control of the driver by means of the liquid pressure or motor driving force generated by the automobile engine. Therefore, the power steering system is also called steering power amplification device.

The power steering system has been widely used in automobile manufacturing in various countries due to the flexibility and lightness of steering control, the increased flexibility in the selection of the steering gear structure design in the design of automobiles, and the ability to absorb the impact of the road surface on the front wheels. . However, the main drawback of a power steering system with a fixed magnification is that if a fixed power steering system is designed to reduce the force of turning the steering wheel while the vehicle is parked or running at a low speed, then the vehicle is traveling at a high speed. At the same time, the fixed power steering system will make the force of turning the steering wheel too small, which is not conducive to the directional control of high-speed cars; if the fixed power steering system is designed to increase the car When turning at high speeds, turning the steering wheel can be very difficult when the car is stopped or running at a low speed.

The application of electronic control technology in the automotive power steering system enables the driving performance of the vehicle to reach a satisfactory level. The electronically controlled power steering system can make the steering light and flexible at low speeds; when the car is steered in the middle-high speed area, it can also guarantee optimal power magnification and stable steering feel, thus improving the handling stability at high speeds. . Electronic Control Power Steering (EPS-Electronic Control Power Steering), according to different power sources can be divided into hydraulic electronically controlled power steering system (hydraulic EPS) and electric electronic control power steering system (electric EPS). The hydraulic EPS is based on the traditional hydraulic power steering system and includes solenoid valves, vehicle speed sensors, and sub-control units for controlling the liquid flow. The electronic control unit controls the solenoid valves according to the detected vehicle speed signals to realize the steering power amplification. Continuously adjustable to meet the steering assist requirements at high and low speeds. Electric EPS uses a DC motor as a power source, and the electronic control unit controls the magnitude and direction of the motor torque based on signals such as steering parameters and vehicle speed. The torque of the motor is decelerated and increased by the electromagnetic clutch through the speed reduction mechanism, and then added to the steering mechanism of the vehicle to obtain a steering force that is compatible with the working conditions.