Force-Controlled MEMS Rotary Microgripper

This paper presents a force-controlled microelectromechanical systems rotary microgripper with integrated electrothermal sensors. The proposed microgripper achieves a large displacement (85 μm) at low driving voltages (≤80 V). Closed-loop force control is implemented to ensure the safety of the operation where the controller gain is experimentally tuned so that the desired response is achieved. One of the main contributions of this work is the implementation of a null-displacement feedback control force-sensing technique, where the controller counteracts the input disturbance (contact force) and an integrated electrothermal displacement sensor provides a feedback signal to close the control loop. In this manner, the contact force is measured without moving the structure. Finally, the effectiveness of the controller and the performance of the proposed microgripper are verified by a set of experiments. The results demonstrate the satisfactory performance of the proposed force-controlled microgripper in a practical application.