Model-Free Trajectory Tracking Control of Two-Particle Magnetic Microrobot

We report a novel model-free trajectory tracking control scheme for two-particle magnetic microrobot (TPMM), which is capable of performing two-dimensional locomotion on a surface in fluid. In the control scheme, the dynamic model of the microrobot and external disturbances are lumped together and treated as the generalized disturbance, which eliminates the complex dynamics modeling of the microrobot due to the hydrodynamics and boundary effect. By employing an extended state observer, the motion states of the microrobot (i.e., position and velocity) are estimated, and the generalized disturbance is compensated. Then, a linear trajectory tracking controller is designed by utilizing the estimated motion states. Furthermore, a visual servoing control system is implemented and extensive real-time trajectory tracking experiments are conducted. The experimental results show the effectiveness of the proposed control scheme for realizing high-precision trajectory tracking for TPMM samples with different body-lengths and surrounding fluids.