Aiming at the difficulty of quantitative analysis of magnetic scale of magnetic grating sensor

the magnetic scale is simplified as rectangular permanent magnet array. Using the molecular current hypothesis

mathematical model for rectangular permanent magnet is established

according to Biot-Savart Law. Analysis shows that the permanent magnet size and air gap are important factors affecting the acquired magnetic induction intensity waveform data. Simulation is performed using the Ansoft Maxwell platform

in the case of fixing the 1 mm thickness of permanent magnet

the magnetic induction intensity change curve in the y direction in the region of 1～ 10 mm different pitch and 0 ～ 5 mm air gap thickness is obtained. Evaluation function is built based on the Fourier transform using response signal distortion as evaluation criterion. The influence of the distance between the Hall element and the pitch of permanent magnet on the response signal is analyzed. According to the quality evaluation function

the optimal air gap range of different pitch sizes of permanent magnets is obtained

which provides theoretical support for the optimization and high performance usage of magnetic grating sensor.