Title

Design of a linear piezomotor for positioning feed drives

Date of Completion

January 1995

Keywords

Engineering, Mechanical

Degree

Ph.D.

Abstract

Feed drives have been used in manufacturing industry for many years and still pose problems, such as positioning accuracy, stiffness, and output force. What makes the design of a feed drive even more challenging is that the positioning accuracy is needed over a longer range of travel. The goal of the research is to develop a linear piezomotor with a nanometer resolution, a high stiffness, and a large output force for positioning feed drives. The objectives are to establish a strategy to ease the design process; to build a global stiffness model to synthesize the flexure mechanisms of the piezomotor based on the energy theorems, and a microdynamic model to optimize the design parameters; and to verify the theoretical results by experimental studies on the linear piezomotor built. While the design strategy resolves the problems involved in the existing designs, the global stiffness modeling provides a useful tool to solve both linearly and non-linearly elastic problems, and the microdynamic modeling allows up to six displacement outputs, six force inputs, and also six initial displacement and velocity conditions. These methodologies make the linear piezomotor design more predictable than a trial-and-error design method does. A laser interferometer and capacitance sensors are used in the performance evaluation of the linear piezomotor. It turns out that the linear piezomotor provides a positioning resolution of 5 nanometers, a stiffness of 90 N/$\mu$m, an output force of 200 N. ^