Design and testing of a large-workspace XY compliant manipulator based on triple-stage parallelogram flexure

Abstract

This paper proposes a new XY compliant parallel manipulator with large workspace and low coupling motion by resorting to planar arrangement of multistage parallelogram mechanisms. The triple-stage parallelogram flexure is chosen as the basic mechanism for motion transmission and decoupling. Its fixed and moving ends adopt planar and spatial connections, respectively. By this connecting scheme, more types of general multistage parallelogram flexures can be constructed. The driving stiffness and resonant frequency of the manipulator are derived based on statics analysis of theoretical mechanics and dynamics analysis via Lagrangian equation. The accuracy of the analytical model is confirmed by performing finite element analysis simulation, and the performance variances of three manipulators are compared. Moreover, a prototype of the XY compliant manipulator has been fabricated and tested. Results show that the workspace of the parallel manipulator is 1.51 cm × 1.48 cm, and the coupling ratios of the two axes are 1.11% and 1.06%, respectively. The volume ratio is introduced as a compactness indicator for comparison study versus existing designs. The centimeter-level stroke can promote the application of XY parallel manipulators in more industrial scenarios.