Real-Time Trajectory Tracking of a Piezoelectric Microrobot Using Asynchronous Fusion of Vision Cameras and Laser Sensors

This study developed a multisensor asynchronous fusion method for vision cameras and laser sensors for real-time tracking of a millimeter-scale piezoelectric microrobot with high sampling rates. The design, manufacture, and realization of the proposed microrobot using a monolithic integrated manufacturing process is realized with a size of 36×36×18 mm and a weight of 4.9 g. Two local estimators for the vision camera and laser sensors are established independently for 2-D tracking of the millimeter-scale microrobot. An asynchronous fusion method for the camera and laser sensors is developed by optimally weighting the two local estimators in a linear minimum variance framework using the Lagrange multiplier method at the synchronized update time. High-precision 2-D trajectory tracking of the proposed microrobot was achieved with an average velocity of 301.6 mm/s and a sampling rate of up to 4000 Hz. Experiments tracking different trajectories of the microrobot at different velocities and sampling rates demonstrated the effectiveness of the proposed fusion method.