Two-dimensional Path Tracking Control of Microrobot Driven by Combined Magnetic Field.

This paper demonstrates the control system of magnetic microrobot driven by combined coils. The combined coils consist of three pairs of Helmholtz coils and three pairs of Maxwell coils. The rotating magnetic field, gradient magnetic field and combined magnetic field model of the combined coils were analyzed. A discrete-time optimal controller based on auto disturbance rejection control technology is used to realize fast response of output magnetic field to current. We have designed a closed-loop controller based on position servo. The control system consists of closed-loops of direction and position. As the sampling frequency of vision based position feedback of microrobot is not high enough, the actual position cannot be transmitted to the control system in time. Kalman filter algorithm is used to predict the position of microrobot in the movement process to improve the accuracy of control. Combined with the magnetic drive device and the proposed microrobot control method, simulation and experiment are carried out to verify the proposed scheme. The results show that the magnetic field driving microrobot is effective and the proposed method can improve the magnetic field response ability and the accuracy of the motion control of microrobot. ¹