Design And Implementation Of Gear Encoder Based On MR Sensor And Interpolation Of Signal

The encoder is the feedback element of the servo closed-loop system,which has an important influence on the control performance of the motor in the servo system.Magnetic encoders are characterized by high responsiveness,high anti vibration grade and oil stain resistance.However,it has low resolution,high precision and high cost.It is difficult to meet the demand of high speed and low cost motion feedback.A new type of gear encoder based on magnetoresistance effect is designed to meet the demand of servo motor and high-speed spindle motor position and speed feedback.Firstly,Based on the current research status and development trend at home and abroad,the semiconductor magnetoresistance effect is studied in combination with the demand of the position and speed feedback of high speed spindle motor.The semiconductor magnetoresistance effect is studied and the key chip selection is carried out.Moreover,it is analyzed that the feasibility of the design of the gear encoder.Secondly,the key technologies of encoder rectifying and interpolation are studied.The methods and ways to reduce DC error,amplitude error and phase error are studied.An improved method of phase error compensation,based on multiplication frequency and phase shifting principle,is proposed.The arctangent interpolation based on CORDIC and the closed loop tracking interpolation method are studied.The simulation model of closed loop tracking interpolation algorithm is built.A method of CORDIC algorithm is proposed to accelerate the calculation of inverse tangent.The feasibility of the method is verified.Lastly,the system hardware design of the gear encoder head is completed.The input and output interfaces of the encoder are analyzed.The results show that the gear encoder achieves the desired goal.It can meet the needs of servo motor and high speed spindle motor position feedback.