Design and testing of high-accuracy curved cross-axis flexural pivots with cable-driven actuation

The cross-axis flexural pivot proved to be a valid tool for replacing the traditional revolute joints in a variety of mechanical systems. However, the rotation axis drift limits its implementation in high-precision applications. This investigation presents a procedure for designing high-accuracy flexural pivots actuated by cable-driven systems. Kinetostatic simulations, resorting to finite element analysis and to chained beam constraint model, have been carried out to analyze the relations among the input and output parameters of the design. The effects of initial curvature on position accuracy, maximum stress, and actuation force have been investigated and several design maps have been generated to support the procedure in each step. The procedure has been applied to the design of high-accuracy pivots and an experimental campaign has been carried out to compare accuracy and kinetostatic performance of the curved configurations to the straight one.