Development of 3-DOF finger module for micro manipulation

A compact and economical 3-DOF finger module for micro manipulation is developed; it is designed for a two-finger micro manipulator which can manipulate micrometer-size objects dexterously like chopsticks. A 3-DOF parallel mechanism for this finger is proposed, and its inverse kinematics between the end effector position and the actuator displacements is formulated. The design parameters are determined so that its workspace volume may be as large as possible. A prototype using three piezo-electric actuators and two types of flexure joints, which are proposed for realizing a compact finger, is developed. The Jacobian matrix used for calculating the actuator displacements corresponding to the given end effector position is obtained by experiments. The repeatability and absolute positioning accuracy - about 2.0[μm] - of this prototype are evaluated.