Research On Control Strategy And Drive Topology Of Rotary Voice Coil Motor

Rotary voice coil motor(RVCM) is widely used in precise position servo control system because of its linear control, high positioning accuracy, and the direct drive. However,with the continuous upgrading of application environment and the rising number of application scenarios, more and more high demands to the control performance of RVCM are put forward in recent years. Thus, it shows great necessary to research on the high performance RVCM control system.The operating principle of RVCM is introduced and its mathematical model is built firstly. On the basis of the mathematical model, ultimate dynamic performances of RVCM under the certain physical limit condition are further discussed, including sinusoidal reference tracking in terms of the amplitude and phase, and the shortest response time without overshoot in step response. The dynamic performances mentioned above directly determine the closed-loop control effect and practical application for RVCM.For the dynamic model of RVCM is difficult to be established and the control accuracy is generally very high, a RVCM control strategy based on the active disturbance rejection control(ADRC) is proposed in this paper. The stability of the extended state observer(ESO) and the feedback control law(FCL) with reference inputs are analyzed respectively and the stability conditions of ESO, FCL and closed-loop ADRC system are given as well. Moreover, based on the bandwidth concept which is carried out according to the system poles configuration,performance of ESOs with the different and same extension orders are analyzed in frequency domain and time domain, and the impact of extension order and bandwidth on the properties of ESO are analyzed too. Furthermore,performance of linear FCL with different reference signals are illustrated. The results show that high-order closed-loop system can be turned into lower-order system, such as equivalent second-order or equivalent first-order, though appropriate parameter configuration. Then single-loop ADRC control strategy and series ADRC control strategy are proposed and are compared with the three-closed-loop PID control compensated by feed-forward speed signal in Matlab/Simulink, and the simulation result show that series ADRC control strategy has higher control accuracy, position control bandwidth and lownoise control signal.In order to suppress torque ripple, noise and the impact on the location accuracy caused by current ripple, the relationship between current ripple and position accuracy is analyzed on the basis of unipolar and bipolar modulation. Further, the multiple-phase topology for RVCM drive is introduced and details the relationship between magnitude of current ripple and module number. About the module current imbalance in multiple-phase drive, a current sharing phase-shift control based on simple sampling method is proposed.Finally, RVCM hardware driving system is designed and the viability and effectiveness of proposed control strategies are verified.