Research On Position Servo Control System Of Rotary Voice Coil Motor With LCL Filter

Rotary voice coil motor(VCM)is a special kind of direct drive motor based on the principle of Lorentz Force.It has been widely used in various industrial applications due to its simple structure,fast response,convenient maintenance and low noise.With the expansion and upgrading of its application,there’s a higher requirement for the control performance and accuracy of the VCM servo systems.This paper mainly discusses the improvement of the performance of the servo system with LCL filter from two perspectives,i.e.drive and control.First of all,this paper discusses the design of LCL filter used for VCM servo system.To avoid the disadvantage of analog drive and chopper drive,this paper proposes chopper driving with LCL filter for VCM.The proposed LCL filter in this paper is used in the servo system,both of whose transient and steady state performance should be taken into consideration.This paper adopts the parameter-scanning method to study the effect of the filter parameters on the armature current ripple and response time.The additional volume is considered since the VCM servo system is used in aerospace applications.The optimal filter parameters are obtained taking all three factors into account.Secondly,this paper explores the PID control strategy of VCM servo system with LCL filter.The switching-frequency-related ripple is attenuated because of the adoption of the LCL filter,but its inherent resonance problem magnifies the harmonic component near the resonant frequency.This paper uses active damping feedback to suppress the resonance phenomenon.The capacitive current feedback coefficient is deduced based on the automatic control theory.The position-speed-current three-closed loop with feedforward control is designed based on Bode plot.And then,this paper explores the ADRC control strategy of VCM servo system with LCL filter.The PID controller for VCM servo system with LCL filter requires additional sensors to suppress the resonance.On the contrary,the ADRC controller can realize this function without any additional sensors.This paper explores two kinds of ADRC controllers,i.e.cascade and direct structures.The effects of the bandwidth of observer and controller are analyzed through Bode plot respectively.And some measures are taken to compensate for the performance limitation caused by insufficient bandwidth.Last of all,the effectiveness of the design of the LCL filter and the performance of the PID and ADRC control strategies are validated through simulation and experiments.Under the condition of insufficient bandwidth,the control strategy with ADRC position loop and PI current loop structure shows the best parameter adaptability and anti-jamming capacity.