On novel compliant mechanisms for remote center motion

This article presents the synthesis, parametric analysis with a semi-empirical model, and experimental validation of novel compliant remote center motion mechanisms with high cross-axis stiffnesses. The literature backs up ample use of rigid links in the synthesis of remote center motion mechanism in various applications. Compliant remote center motion mechanisms reported earlier are cable-driven mechanisms for endoscopy manipulation. On the contrary, in this article we propose spatial, compliant-link (leaf flexure link) remote center motion mechanisms (patent pending). Synthesis of the proposed compliant mechanism poses the main challenge of achieving precise remote center motion with prominent cross-axis stiffnesses. The proposed design is conceived using angularly assembled compliant links (with fixed-fixed boundary) which upon application of force undergo simultaneous twisting and bending resulting in the proposed remote center motion. Higher width as compared to the thickness along with angular arrangement gives the desired cross-axis stiffness. Extensive nonlinear finite element analysis establishes the accuracy of the remote center motion, high cross-axis stiffnesses, and the accuracy of the proposed semi-empirical model based on parametric analysis. Furthermore, the proposed mechanism is fabricated and preliminary experiments validate remote center motion in an example case.