Contents I. INTRODUCTION
In conventional mechanisms, revolute joints consisting of a revolute shaft and a bearing are typically used. These revolute joints have several advantageous characteristics, such as high-speed rotation and structural rigidity. How-ever, revolute joints commonly require lubrication and high-precision machining to minimize mechanical backlash in high-precision robots. In compliant mechanisms, one or more elastic structures deform to transmit or transform the power in place of conventional revolute joints [1]–[3]. Compliant mechanisms have no backlash, require no lubrication, and are free from machine noise and abrasion powder. In addition, usually conventional mechanisms, compliant mechanisms can be commonly integrated into compact, lightweight, and simple structures. On the other hand, parallel mechanisms [4] generally have the advantages of high rigidity, output, accuracy, and backdrivability thanks to their multi-legged structure and fixed actuators. Since compliant mechanisms inherently have poor accuracy, especially in multi-DOF motions, the integration of compliant parallel mechanisms is a rational approach.
