A novel compliance modeling method for compliant parallel mechanisms and its application

Abstract

A novel compliance modeling method for flexure-hinge-based (FHB) compliant parallel mechanisms is proposed, where internal constraint of branches is taken into consideration based on flexibility-center-decomposition method of compliance matrix and screw theory. The modeling method is employed to transform deformation problem of branches into statics and kinematics problems of pseudo-rigid-body branches. Firstly, the virtual branch is established and its corresponding decoupled compliance matrix is obtained. Then, the compliance modeling of the whole mechanism is obtained by static equilibrium equation and kinematic relations. Secondly, a constraint performance index reflecting ability to constrain undesirable deformation of the compliant parallel mechanism is presented based on the decoupled compliance matrix. The effectiveness of the constraint performance index is verified through analysis of degree of freedom (DoF) of the 3-SS mechanism. Finally, the proposed modeling method and performance index are used in design and analysis of a novel RPR compliant parallel mechanism. To our knowledge, constraint performance index is firstly proposed for assessing the ability to constrain undesirable deformation of the compliant parallel mechanism.