Position Optimization of the Roberts – Chebyshev Cognate – Compliant Mechanisms

Abstract

Instead of relying solely on moving rigid-body joints, compliant mechanisms motion is defined, thanks to their joints' relative flexibility, i.e., flexure hinges. As alternatives to the rigid-body Roberts-Chebyshev mechanism, which allows the coupler point to be directed along a roughly rectilinear route, two compliant cognate mechanisms have been devised in this study. Guaranteeing the same input-output coupler tracing point, these cognate mechanisms have different link lengths but come from the same kinematic chain. For each of the two examples of newly built cognate-compliant mechanisms, the "coupler" point's guiding accuracy on the rectilinear trace (minimum divergence between the exact rectilinear and realized trace) and the mobility have been computed. Due to the need for comparison, newly obtained compliant mechanisms are often designed with flexure hinges of already widely known shapes. Hence, the cognate-compliant mechanisms with notch joints (circular flexure hinges) have first been analyzed. The introduction of undercut flexure hinges in the compliant structure and the use of position optimization tools have improved the performance of the cognate-compliant mechanism with better guidance accuracy and greater mobility.