Development of a Passive Compliant Mechanism for Measurement of Micro/Nanoscale Planar 3-DOF Motions

This paper presents the design, optimization, and computational and experimental performance evaluations of a passively actuated, monolithic, compliant mechanism. The mechanism is designed to be mounted on or built into any precision positioning stage, which produces three degree-of-freedom (3-DOF) planar motions. It transforms such movements into linear motions, which can then be measured using laser interferometry-based sensing and measurement techniques commonly used for translational axes. This methodology reduces the introduction of geometric errors into sensor measurements, and bypasses the need for increased complexity sensing systems. A computational technique is employed to optimize the mechanism's performance, in particular, to ensure the kinematic relationships match a set of desired relationships. Computational analysis is then employed to predict the performance of the mechanism throughout the workspace of a coupled positioning stage, and the errors are shown to vary linearly with the input position. This allows the errors to be corrected through calibration. A prototype is manufactured and experimentally tested, confirming the ability of the proposed mechanism to permit measurements of 3-DOF motions.