Piezo Driven 3 D.O.F. Actuator for Robot Hands
Haruhisa Kawasaki* and Masahito Yashima**
*Kanazawa Institute of Technology, 7-1 Ohgi-ga-oka Nonoichi, Ishikawa 921,Japan
**University of Tohoku, Aramaki-Aza-Aoba, Sendai, Miyagi 980, Japan
Robot arms such as those used for assembling optical parts or semiconductors require high positioning accuracy. However, the most accurate robot arms at present can be positioned to an accuracy of 10μm at best. In order to realize accurate arm positioning, robots should be equipped with precise positioning actuators. This paper describes an accurate, lightweight piezo-driven actuator. The actuator functions using an inchworm movement and is driven by six piezoelectric elements. It moves precisely along the X, Y, and θ axes. A step translation of 4.2μm, step rotation of 0.52mrad, and closed-loop positional accuracy of ±0.05μm are achieved. Also discussed is the mechanical relationship between the piezoelectric elements holding the actuator and the plate.