Research And Design Of Steering Angle And Torque Sensor For Automotive Vehicle

Torque sensors and steering angle sensors are widely used among automotive sensors. As an important part of the electronic power steering system (EPS), torque sensor plays a role in measuring the torque of the steering wheel, and provides a basis for the magnitude of the assistant power. The latest EPS also need the signal of the steering angle for the function of self-aligning and damping. In addition, more and more sensors are connected to the controller area network (CAN) following the extensive application of CAN communication. They apply the sensing data to the whole car automotive system, which greatly raise the utilization of sensor resources. For instance, the electronic stability program (ESP) also needs the signal of steering angle. Steering angle sensor is capable to offer data to EPS and ESP simultaneously.In this thesis, I briefly introduce the development of torque sensor and steering angle sensor, as well as the measuring principle of several kinds of sensors. And I put the emphasis on the principle of the designed torque and steering angle sensor based on giant magneto-resistive (GMR) effect. Finally, I draw the following conclusion.1. Improve the resolution of torque output by using the method of gear increaser and enlarge the scale of steering angle output by using the method of angle difference. Show the derivation of the method of calculating torque and steering angle as well as explain it in theory.2. Design the mechanism, hardware circuit and measuring program as well as making several sample sensors. Measure and analyze their linearity, hysteresis and repeatability. The torque output has a linearity of 1.01%, a hysteresis of 0.509% and a repeatability of 0.729%. The steering angle output has a linearity of 0.483%, a hysteresis of 0.248% and a repeatability of 0.342%.3. Analyze the resolution of the sensor’s torque output by the method of collecting data via CAN interface. Its torque output resolution is 0.0624° By the theoretical derivation, the resolution can be 0.00147°. So there is still some room for improvement.