Simplified kinematic calibration for a class of parallel mechanism

Calibration methods and parameter estimation analyses of a class of parallel mechanisms are discussed in order to achieve a nano-modon stage applied in the machining of high quality optical devices. The paper includes mechanical structure of Delta type parallel mechanism, its kinematics analyses for calibration, two calibration methods and their comparisons in the aspects of parameter errors, final achieved accuracy and simple procedure. Exclusion of orientation data will be also discussed for the simplicity of measurements in the calibration procedure.

1. Introduction

In a recent advancement of micro and nano activities a fine positioning stage is required for machining, observation, manipulation, etc. The parallel mechanism has good advantages for this kind of application with respect to the achievements of fine positioning capability and compact structure. There have been a number of researches and developments, for example, Hara analyzed and built a small stage using flexure hinges [1], Hiraki devised 3-D measuring system [2], Tanikawa applied some types of parallel mechanisms to two finger hand for micromanipulation system [3].