Development and experiment of a micropositioning parallel manipulator

This paper describes the design, simulation, development, and experiment of a six degree-of-freedom micropositioning parallel manipulator. A movable stage was supported with six links, each of which extends with a dc-servo micropositioning actuator. In case of parallel manipulator, while the solution of the inverse kinematics is easily found by the vectors of the links which are composed of the joint coordinates in base and platform, but forward kinematic is not easily solved because of the nonlinearity and complexity of the parallel manipulator's kinematic output equation with the multi-solutions. The movable range of the prototype was ±25mm in the x- and y-directions and ±12.5mm in the z-direction. The minimum incremental motion of the prototype was 1μm in the x- and y-directions and 0.5μm in the z-direction. The repeatability of the prototype was ±2μm in the x- and y-directions and ±1μm in the z-direction. The motion performance was also evaluated by not only the computer simulation of CAD model but also the experiment using a capacitive sensor system.