Microrobotic manipulation at time-varying air-liquid interface for high-precise watch-hand alignment

Micromanipulation is a core technique in precise manufacturing and mechatronics. However, current researchers mainly focus on the time-invariant normal environment, whereas complex manipulation at time-varying air-liquid interface is rarely studied, such as the watch-hand alignment problem in industry. To address the above challenge, this paper presents a microrobotic system and corresponding control strategy by modeling the watch-hand movement dynamically at time-varying air-liquid interface. In this paper, a microrobotic manipulation system with five degrees of freedom is developed and integrated with an optical microscopy. Then, the dynamic model of watch-hand is built through Lagrange equation, including the viscoelastic force from glue and the lateral capillary force at the air-liquid interface. After that, a proportional-integral-derivative controller is designed to guarantee the accuracy of the alignment process. Lastly, the accuracy and efficiency of the proposed system is verified through both simulation and experiments. This research provides a common solution for the precise micromanipulation at time-varying air-liquid interface, which would greatly promote the micromanufacturing and microfabrication in lab and industry.