Optimization of a near-zero-center-shift compliant pivot for large motion range and high bearing stiffness

Compliant pivots are employed in mechanical systems to achieve precise motions through the elastic deflections of the flexible elements, serving as substitutes for rigid joints. However, these pivots often encounter challenges such as a limited range of motion, significant axis shift, and low radial stiffness due to the distributed compliance of the flexible elements. To address these issues, this study introduces a novel design. This design is composed of three identical building blocks arranged in a circle array. The extended range of motion is achieved by serially connecting the flexible beams within the building blocks. The design's symmetry ensures the nearly zeros axis shift, while the single degree of freedom and the virtual constraint enhances radial stiffness. A pivot with optimal combination properties is obtained through kinetostatic modeling and optimization, and experimental results validated its performance.