Model-Based Angular Scan Error Correction of an Electrothermally-Actuated MEMS Mirror

Sensors

Hao Zhang²  Dacheng Xu²  Xiaoyang Zhang³  Qiao Chen¹  Huikai Xie³  Suiqiong Li² 

[1] Wuxi WiO Technology Co. Ltd, Wuxi 214000, China;School of Electronic and Information Engineering, Soochow University, Suzhou 215006, China;Department of Electrical and Computer Engineering, University of Florida, Gainesville, Florida, FL 32611-6200, USA;

关键词: electrothermal actuator;    MEMS mirror;    static deviation;    model based open-loop control;   

DOI  :  10.3390/s151229840

来源: mdpi

【 摘 要 】

In this paper, the actuation behavior of a two-axis electrothermal MEMS (Microelectromechanical Systems) mirror typically used in miniature optical scanning probes and optical switches is investigated. The MEMS mirror consists of four thermal bimorph actuators symmetrically located at the four sides of a central mirror plate. Experiments show that an actuation characteristics difference of as much as 4.0% exists among the four actuators due to process variations, which leads to an average angular scan error of 0.03°. A mathematical model between the actuator input voltage and the mirror-plate position has been developed to predict the actuation behavior of the mirror. It is a four-input, four-output model that takes into account the thermal-mechanical coupling and the differences among the four actuators; the vertical positions of the ends of the four actuators are also monitored. Based on this model, an open-loop control method is established to achieve accurate angular scanning. This model-based open loop control has been experimentally verified and is useful for the accurate control of the mirror. With this control method, the precise actuation of the mirror solely depends on the model prediction and does not need the real-time mirror position monitoring and feedback, greatly simplifying the MEMS control system.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.