Micro/miniature shape memory alloy actuator

Shape memory alloy (SMA) has great potential for microminiature actuators. The feasibility is discussed, and theoretical estimates based on scale effect are presented. Control schemes for microminiature SMA servoactuators are discussed, and a control scheme is proposed. Combined with electric resistance feedback and position feedback, it enables the author to control stiffness of SMA directly and to sense force without a force sensor. Experimental verifications are reported. The application of a miniature SMA actuator to a miniature clean gripper with position-force hybrid control for microelectronics manufacture is presented. Fabrication of a thin film micro SMA actuator is investigated