Displacement measurement of a thermally actuated polymer microrobotic gripper using the optical focus method

With the maturing design of microelectrical mechanism systems, the metrology for MEMS is becoming the hot research in the microsystem technology. In this paper, we used the sum-modified-Laplacian (SML) focus measure and depth estimation method to measure the tip deflection of a thermally actuated polymer microrobotic actuator. Twenty-three under-water images of the microactuator working at the temperature of 42°C have been used to illustrate the idea of measuring the tip deflection using optical focusing method. The results showed in the paper can be used to metrology MEMS. By optical focus method, we can measure the tip defection, which can act as a feedback input to the actuator. So, an accurate control of the motion of actuator can be achieved.