End effector actuation with a solid state motor

An actuator technology program is in progress to develop miniature motors, joints, and links suitable for modular placement in structures approaching the human hand in size, dexterity and weight. The end-effector device described is a small gripper with tweezer action. This is a first step in a program which will evolve from basic precision miniature grippers to more sophisticated and dextrous multi-jointed end effectors. The gripper can hold objects up to 0.5 in. wide, and it is intended for a circuit-board-level scale of operation. The jaw motor is piezoelectric and works by resonance operation in the longitudinal vibration mode to move a slide plate in a linear fashion. The slide plate is coupled to a mechanism in a 0.5 in.³-volume housing which converts the linear slide motion to lateral jaw action. The motion will eventually be controlled by linear encoders for position control and one or more strain gages to develop a force servo controller. Motor performance, modeling, and the smaller gripper are described