Design Study On Angle Sensor Of Electric Power Steering System

The sensor technology as one of the three pillars in the information industry, which is the source of all information in modern society. With the rapid development of automotive industry and automotive electronic control technology, also contributed the sensor technology to leap at the same time. At present, there are about thousands of different function sensors installed in one car, steering wheel angle sensor is one of them. Angle sensor can detect the rotation angle signal of steering wheel and sent it to the ECU of the automotive electric power steering (EPS) system, so as to realize the power of the motor system to EPS real-time coordinated torque control, which is an important part of the EPS system. Therefore, to design a superior performance sensor which can detect range of steering wheel angle is absolutely one of important solutions to optimize the EPS system.Through studying the application status of the angle sensor, introducing the main angle sensors which are applied on the market at present, and analyzing the advantages and disadvantages of all kinds of angle sensors. Under the premise of grasping the current development trend of integration and intelligent, this paper proposing a non-contact absolute angle sensor based on magnetoelectricity effect. The angle sensor system's main mechanical components was introduced in the paper, also the paper included the number of the teeth on the planetary gear and the installation location of the selected magnets. By applying the software Electronic Design Automation tools to design the hardware circuit of the angle sensor system, this paper used the method of two integrated core chip AS5043which was communicated on the daisy associated mode. And in order to realize the integration of Angle sensor design, the angle sensor system has used the data acquisition and processing chip PIC18F2480of the Microchip Company which integrated high performance and enhanced function.The article focuses on the research of software implementation to the sensor system, uses the superior signal processing functions of PIC18F2480, adopts the digital correlation algorithm of phase difference to write the angle algorithm of the sensor system to realize the intelligent design of the steering wheel angle sensor. Finally, use the PIC microcontroller integrated development software MPALB IDE to complete the write of the sensor system software programs and the debug of the system. Finally, an angle sensor prototype is produced according to the design presented in this paper, and the experimental certification and performance comparation are carried out to the performance of the prototype. Proved by experiments, the angle sensor can achieve an accurate measurement to the steering wheel±720°angle signal, the measurement accuracy within±0.3°, which in line with national standards requires to the angle sensor. The innovation of this paper is to use the daisy-associated mode of the integrated angle encoders AS5043to achieve the acquisition of angle signal, which reduced the discrete components of the circuit greatly, then simplify the signal processing circuit of the sensor system.