System Overview Of Automobile Electric Power Steering Electric Power Steering system, EPS (Electric Power Steering, abbreviation) is a kind of rely on motor directly provide auxiliary torque of the Power Steering system, with the traditional HPS Hydraulic Power Steering system (Hydraulic Power Steering) compared to, EPS system has many advantages. EPS is mainly composed of torque sensor, speed sensor, motor, deceleration body and electronic control unit (ECU), etc. Development history of the development process of the car, the steering system has experienced four stages of development:From the initial mechanical Steering system (Manual Steering, MS) for the development of Hydraulic Power Steering system (Hydraulic Power Steering, referred to as HPS), then the electronically controlled Hydraulic Power Steering system (company Hydraulic Power Steering, the EHPS) and Electric Power Steering system (Electric Power Steering, hereinafter referred to as EPS).Mechanical steering system of automobile assembly, in the car parking and driving at low speed when the drivers steering load is too heavy, in order to solve this problem, the United States GM company pioneered in the 1950 s adopted the hydraulic power steering system on the car. However, hydraulic power steering system is unable to take into account the vehicle at low speed when the steering portability and high-speed stability, so in 1983, Japan Koyo company launched have speed induction function of electronically controlled hydraulic power steering system. This new type of steering system can provide decreased gradually with the increase of speed, steering, but complex, high cost, and cannot be overcome hydraulic system itself has many shortcomings, is a kind of between the hydraulic power steering and the transition between the electric power steering. In 1988, Japan Suzuki company first in the small car Cervo equipped with Koyo company research and development of steering power type electric power steering system; In 1990, the Japanese Honda company also adopted the independent research and development on the NSX sports cars of the rack power type electric power steering system, from then on, unveiled on auto electric power steering applications history. Type and advantages and disadvantages of our common power steering are mechanical hydraulic booster, electronic hydraulic power and electric power.The mechanical hydraulic boosterMechanical and hydraulic power is our one of the most common dynamical method, it was born in 1902, by the British Frederick w. Lanchester invention, and the earliest application is delayed for half a century later, the commercialization of the Chrysler 1951 mature hydraulic steering system is applied in the Imperial line disappears. Because the technology is mature and reliable, and low cost, has been widely spread.Mechanical hydraulic booster system main component of hydraulic pump, tubing, pressure fluid control valve, V belt, storage tanks, etc. This power is part of the engine power output into hydraulic pump pressure, auxiliary force on steering system, so that the tires.The electronic hydraulic pressure boostDue to mechanical hydraulic power consumption need sharp engine power, so people on the basis of mechanical hydraulic booster was improved, developed a more save energy consumption of electronic hydraulic power steering system. The system of the steering pump is no longer directly driven by the engine, but by the motor to drive, and on the basis of before equipped with the electric control system, make to the size of the auxiliary power is not only related to the steering Angle, also related to the speed. Mechanical structure increased hydraulic reaction equipment and flow distributing valve, the new electronic control system including the speed sensor, electromagnetic valve, steering ECU, etc.Electric powerEPS is the abbreviation of English for Electric Power Steering, Electric Power Steering system. Electric power steering system is the development direction of automobile steering system. The system provided by the electric power machine direct steering, eliminating the hydraulic power steering system required for the power steering pumps, hoses, hydraulic oil, conveyor belt and pulley mounted on the engine, save energy, and protect the environment. In addition, also has the easy, flexible assembly and under various conditions can provide steering characteristics. It is with these advantages, electric power steering system as a new steering technology, will challenge the everyone is very familiar with, have the hydraulic steering system with more than 50 years history.Driver in manipulation of the steering wheel steering, steering and steering wheel torque sensor detects the size of the torque, the voltage signal to the electronic control unit, the electronic control unit according to detect torque of the torque sensor voltage signals, the rotation direction and speed, etc.,