Analysis and optimization of a micro-displacement sensor for compliant microgripper

This paper proposes an analysis and optimization of new micro-displacement sensor for a compliant microgripper. This gripper is embedded with strain gauges at the flexure hinges to become a displacement sensor in the range of micrometer. In addition, this paper also presents an effective approach to enhance the first natural frequency of the microgripper. Specifically, the silicone rubber is used to fill the open cavities of the gripper in order to increase the stiffness, and as a result the frequency shows a relative improvement. It reveals that the gripper can realize the necessary displacement with the embedded sensor element. The stiffness of gripper can be reinforced by the rubber. As a result the frequency of the gripper is improved. The displacement and frequency are then optimized via using the differential evolution algorithm. The optimal result indicates that the gripper possesses an infinite fatigue life of 5.92 × 107 cycles for producing a large range of motion of 660 µm and a frequency of 326 Hz. The prototype is fabricated via wire electrical discharged machining. The experimental results are in a good an agreement with the predicted and analyzed ones.