A Study on the Small-size Self-propelled Stewart-platform

Abstract

This paper describes a self-propelled Stewart-platform. The Stewart-platform usually consists of a base platform, a moving platform, and linear actuators connecting both the platforms. We use six stacked-type piezoelectric actuators as the linear actuators. Mechanical joints connect the linear actuators and both the platforms. We insert electromagnets between the linear actuators and the base platform instead of the mechanical joints. This structure enables the Stewart-platfom to move on a surface by using the principle of an inchworm. While the electromagnets fix the linear actuators on the base platform, the proposed Stewart-platform realizes a precise 6-DOF motion. Control signals are designed for the small displacement based on the inverse kinematics, and for the wide working area based on the principle of an inchworm. The position and orientation of the moving platform is measured, and some experimental results indicate the feasibility of the proposed mechanism. The mechanism is effective for a precise positioning system which has unlimitted working area.