Research On Contactless Electromagnetic Inductive Angle Sensor Used In EPS

At present, the auto electric power steering (EPS) system are already in a growing number of cars to replace the traditional hydraulic power steering system. Steering wheel Angle sensor, as one of the core technology of EPS system, a direct impact on the power performance of EPS system, is completed in the process of driving vehicle active sensors necessary for correction function. In this paper, through the methods of theoretical analysis and simulation, we design a non-contact electromagnetic induction type Angle sensor.Non-contact electromagnetic induction study Angle sensor are presented in this paper, starting from the theory of electromagnetism, analyzes the law of electromagnetic induction and the principle of eddy current effect. Analysis of internal structure of various parts. Demonstrate how hardware structure by changing the sensor so as to realize the change of the internal magnetic field sensor, and how the change of the magnetic field changes the voltage signal. Using Ansoft electromagnetic finite element analysis software Maxwell electromagnetic coupling system for finite element simulation of sensors, each parameter in the analysis of electromagnetic coupling system of space magnetic field and the influence of coil inductance, based on the design of drive coil, receiving coil and rotor structure, material parameters. And when the rotor rotates through the analysis of the transient field output signal of electromagnetic coupling system. With reference to the results of simulation design and arrangement of the excitation coil and three groups receiving coil form.Simulated electronic as well as the high frequency signal processing knowledge, oscillating excitation coil circuit design, signal processing circuit, receiving coil and selecting suitable MCU chip used in processing the large signal and through the corresponding algorithm, according to the required output of digital or analog signal value. And with the aid of EDA software rendering experimental circuit board, to test the output signal. Measuring the accuracy and repeatability is good or bad.Using Matlab Simulink module Angle signal algorithm simulation model is set up. Describe how to implement sensor through three sets of signal 40°and 360°of measurement. And when to join rotary encoder signal after, all the way through the cursor algorithm measuring more than 1440°. To verify the feasibility of the algorithm and the functional. And compare with the simulation results.