MEMS Microgripper Actuators and Sensors: The State-of-the-Art Survey

In recent years, microelectromechanical systems (MEMS) have been widely applied in diverse science and engineering domains. MEMS-based microgrippers provide advantages in terms of compact size and low cost, and hence play an important role in microassembly and micromanipulation fields for manipulating micromechanical elements, biological cells, etc. During the past two decades, microactuators based on different actuation principles such as shapememory alloys, electrostatic, electrothermal, piezoelectric, pneumatic and electromagnetic approaches have been devised to drive MEMS microgrippers. Moreover, the integrated position and force sensors can deliver real-time feedback signals to protect both the microgripper and grasped object from damaging. In addition, a number of patents have been devoted to this area. This paper presents a state-of-the-art overview of recent development in the actuators (electrostatic, electrothermal, micro-pneumatic, electromagnetic, shape memory alloy and other actuators) and sensors (optical method, piezoresistive force sensor, capacitive force sensor and other developments). By providing detailed comparisons among them, some guidelines of selection have been underlined for different application scenarios such as biomedical and biological applications, micro-manufacturing and so on. Keywords: Force feedback, force sensor, MEMS, microactuator, microgripper, micromanipulation