Development On EPS Torque Angle Sensor And EPS Controller

Electric power steering system is the world's most advanced car s teering device.It has very broad application prospects,because of its high efficiency,low pollution,low power consumption and good flexibility and is gradually replacing the advantages of hydraulic power system.EPS controller and torque sensor are two core components for the EPS system,determining the performance of the entire EPS steering system.So it has very important research significance.In this dissertation,EPS controller and torque sensor development status of a comprehensive and in-depth analysis.The domestic EPS torque sensor is low precision,short life,foreign sensors,although the accuracy and stability of the higher price but more expensive.An anisotropic magnetoresistive principle is used to design a torque angle sensor,achieve non-contact torque and angle measurement.Designing reasonable hardware circuit and software program to ensure that the sensor accuracy to meet the requirements of automotive.For a long time,the EPS controller does not require steering wheel corner signals,but with the development the advanced EPS control strategy will need corner signal as an input signal.The torque angle sensor developed in this paper can realize the simultaneous measurement of the steering wheel torque signal and the corner signal.The torque sensor outputs digital signal with CAN communication interface and PWM interface,thus improved antiinterference ability.A EPS controller is designed and developed based on the automotive chip MC9S12.Analysis power control,return control and active damping control of the EPS controller.EPS controller according to the signals of steering wheel torque and the speed to determine the current driving conditions.Take the appropriate power strategy to control the torque applied to the motor output.A bus communication interface between the EPS controller and other electronic devices to facilitate the diversification of the controller is designed.The test experiment of EPS torque angle sensor and controller is carried out.The torque signal and angle signal of EPS sensor are calibrated.The non-linearity is ±1.3%,fiducial error is 1.5%,sensitivity is 0.62 ?s /°,resolution is 0.9°,and the main sources of sensor error are analyzed;The EPS system boost characteristic curve and input and output torque curve are tested.The test results show that the developed EPS torque angle sensor and controller can meet the design requirements.