Experimental Study on the Life and Nonlinear Actuation Behaviors of V-shaped SU-8 Electrothermal Microactuators

This paper presents an experimental study on the life and nonlinear actuation behaviors of the V-shaped SU-8 based electrothermal microactuators. The copper and SU-8 photoresist are used to fabricate the V-shaped electrothermal microactuators in this work. The combination of the two materials offers large motion actuation and many flexibilities for micro-robot gripper integration and designs. For the manipulation of micro-scaled objects, such as biological cells, the micro-robot grippers are required to move fairly accurate so not to cause any damage to the micro-object. In real-world micro-actuations, however, the nonlinearities of the electrothermal actuation add inaccuracies and even uncertainties to the control of the micro-robot grippers. This results in challenges for accurately controlling the micromanipulations with mechanical micro-robot grippers. In this work, three sources of nonlinearity, i.e., material properties, oxidation, and failure, are investigated experimentally in both static and dynamic aspects. Detailed discussions and experimental results are given to provide insight and guidance on the appropriate actuation and control of the V-shaped electrothermal microactuators and micro-robot grippers.