Development of a “walking drive” ultraprecision positioner

Abstract The present paper presents a new mechanism to feed a precision table continuously over a long stroke with high rigidity by utilizing deformations of piezoelectric actuators. A driving method names “walking drive” is employed for the mechanism with which the table is driven in a similar way to the walking motions in animals. A precision feed device is developed, and ultraprecision positioning experiments are carried out by using the device combined with a laser-feedback system developed. It is confirmed that the positioner driven by the walking drive has the following advantages: (1) positioning resolution of 5 nm is realized with a simple control method and a simple mechanism, because of no friction against the feed motion; (2) smooth continuous path control with the following error of less than 10 nm is realized over a long stroke despite short strokes of the piezoelectric actuators; and (3) high stiffness of greater than 350 N/μm is realized in the feed direction.