Research on PZT bimorph microgripper system

Many kinds of microgrippers have been developed for handling and manipulating micro-sized objects in the fields of various applications. However, the micro-force sensing is still one of the most troublesome problems to improve the reliability of manipulation. To circumvent the problem, in this paper, a microgripper with the structure of dual cantilevers, which is driven by two PZT bimorphs, was designed for the requirement of microassembly tasks. The piezoelectric bimorph model was built, and the displacement-voltage relationship was analysed. In order to obtain the micro force, a Wheatstone bridge circuit that was made up of resistance strain gauge sticked on the root of the PZT bimorph was introduced, sensing the signal because of the strain of the cantilever. Then, according to the sensor signal, PC monitoring system can adjust actuating voltage to achieve safe handling. The experiment results testify that the gripper can work reliably and safely, it satisfies the task of micro assembly.