A microstep control approach for a millimeter-sized omni-directional mobile microrobot actuated by 3-mm-electromagnetic micromotors

This paper presents a novel microstep control approach for improving the positioning precision of a millimeter-sized omni-directional mobile microrobot. The microrobot that is designed for microassembly in a microfactory is driven by three electromagnetic micromotors. The structures of both the microrobot and the micromotor are described in the paper. The torque vectors synthesis method (TVSM) is developed and the torque self-balance principle (TSBP) is employed to realize the microstep control. The control circuit that needs a complex digital logic is devised with a complex programmable logic device (CPLD). The experiments using a hard disk and the real microrobot demonstrated the validity and performance of TVSM and TSBP. And the angular step precision of the microrobot is increased by three times compared to the normal control.