Research On Position Signal Subdivision And Speed Fluctuation Suppression Strategy Of Coarse Aiming Servo System

Because the permanent magnet torque motor has the advantages of no intermediate transmission link,high torque density,and high response speed,and its pole pair number is large,the volume is small,the mass is small,and the structure is relatively simple,it can meet the high requirements of the coarse aiming system for the motor in the space laser communication system.This subject takes permanent magnet torque motors as the object and conducts research with the goal of being able to operate stably at low speeds.First,the working principle of the permanent magnet torque motor is analyzed,the mathematical model of the permanent magnet torque motor is established based on the principle,and the vector control simulation model of the permanent magnet torque motor is built.Based on the permanent magnet torque motor vector control system,some influencing factors when the motor is running at low speed are analyzed,mainly the influence of load torque fluctuation,the influence of wave torque,and the delay and error of speed detection.These provide a basis and theoretical basis for the follow-up.Then since the permanent magnet torque motor servo system runs smoothly at low speeds,the accuracy of the speed feedback signal needs to be improved,and the speed signal is generally obtained by the inverse difference of the position signal,a closed-loop tracking subdivision method is proposed to improve the resolution of the sin-cos encoder.In the actual situation,the output signal of the sine-cosine encoder is not an ideal sine-cosine signal,and there will be DC offset,amplitude error and phase error.The existence of these errors will have an impact on the results of the subdivision,and the three types of errors have been compensated separately.Next,aiming at the speed fluctuation of the permanent magnet torque motor servo system running at low speed,combined with the vector control system,an improved linear auto disturbance rejection control strategy is proposed to be applied to the speed loop controller.The current loop still uses the PI control strategy.By comparing with the speed loop adopting PI control strategy and traditional linear active disturbance rejection control strategy,it shows that this control strategy can reduce the speed fluctuation.Finally,an experimental platform for the permanent magnet torque motor servo system with the DSP chip model TMS320F28379 D as the control core was built.By writing a software program in it,the closed-loop tracking and subdivision strategy proposed in this article and the correction technology of the output signal of the sine-cosine encoder and the improved linear active disturbance rejection control strategy of the speed loop are verified on the hardware experimental platform.The experimental results obtained show that the proposed strategy is feasible.