GMR Sensor's Application And Simulation Analysis On Electric Power Steering System

Electric power steering system is based on the traditional mechanical steering system , according to the speed signals , torque signals and angle signals, through the electronic control device makes the motor producing corresponding size and direction of auxiliary torque, which can help the driver to turn and get the best characteristics of steering system. This technology is already mature in the technology abroad, and most foreign cars have been matched to the system which plays a very good results. Electric power steering system is at the development stage in China, compared with foreign technology there is great room for growth. As technology advances and the development of the domestic auto industry, electric power steering system will achieve good development.In the electric power steering system, sensors detect the steering wheel's angle and torque. It is the "eyes" of control system. The quality of the control system, largely depends on the detection system's "vision". So the sensor is very important in the system. Sensor technology is already one of the most important technologies.This paper presents a new sensor design method and structure. First of all, It introduced the angle measurement chip (TLE5011) in detail which is based on magnetoresistive effect by Infineon company. And then, do some experiments to test the chip , as a result it obtains a good output characteristics. Last ,combined with BI company's sensor shape, this article designed a comprehensive measure steering angle and torque's sensors, which is based on Infineon company's magneto resistive effect angle measurement chip - TLE5011. And then manufactured sensor sample and its detection system. The test results show that the angle signal fully meet the system requirements, but torque signal is temporarily unable to meet the requirements. It is proposed that increase the transmission ratio as a solution for the issue, and then design a specific machinery .In the simulation section,make the sensor and the EPS tegether, do some simulation of control strategy ,such as assistance and returnability.In the assistant characteristic simulation, established a steering system dynamics model , then do simulation for the assistance and vehicle experiments in situ. It is indicated that the model is right because the contrast of the simulation and experiments is alike. So it is offer a method for torsion bar's design. In the align characteristic simulation, it has a study on mechanical align angle by simulation . Then base on the result , it comes up with align control strategy and do it . As a result , it is improved that the model is right. At last do some simulation by changing the transmission ratio and moment of inertia, then point out the consider element.