Measurement of the dynamic response of MEMS thermal actuators based on blurred still images by wavelet transform

A novel method to experimentally determine the dynamic response of MEMS thermal actuators based onblurred still images of motion is presented. The apex displacement of thermal actuators proves to be a first-orderlinear system, whose dynamic response is depended on the system coefficient. In the frequency domain, the systemcoefficient of actuators excited by sinusoidal wave can be obtained from the fitted curve of vibration amplitude againstfrequency. An improved wavelet transform detection algorithm is proposed to acquire the vibration amplitude fromblurred images taken by an ordinary camera. Compared with the conventional optical measurement method, theproposed method uses only still images instead of complex laser and optical reflecting systems, which has greatpotential for wide application. For the actuator in this study, the measured response time by blurred images and highspeedcamera method are 14.87 and 15.25 ms with a deviation of 2.5%, which indicates the proposed method canobtain sufficient accurate results without sophisticated equipment and high cost.