Characteristics of Statically Indeterminate Symmetric Flexure Structures

Abstract

Statically indeterminate symmetric (SIS) flexure structures are symmetric structures with “clamped-clamped” boundary conditions. The static indeterminacy and topological symmetry significantly attenuate the parasitic motions associated with statically determinate flexure structures. Hence, SIS flexure structures feature decoupled linear and angular motions, improved motion accuracy, high stiffness, and high stability. Although SIS flexure structures have been more frequently utilized as prismatic joints, they can also be utilized as revolute joints. This study systematically investigates the characteristics of SIS flexure structures. Based on the unified compliance models of a single flexure hinge, analytical compliance models of two fundamental types of SIS flexure structures are established. In 1-degree-of-freedom or planar applications, multiple SIS-based structures can also be integrated into various configurations to transmit linear or angular motions. Corresponding stiffness models are also established. The characteristics and possible applications of the SIS flexure structures are computationally investigated through case studies. Ultimately, several SIS prototypes are manufactured, and the modeling accuracy of the established stiffness models is experimentally verified.