A compliant-mechanism-based lockable prismatic joint for high-load morphing structures
Lockable joints are widely used in robotic systems and adaptive structures for energy management and/or topology reconfiguration. However, it is still challenging to design a joint with desired properties, including high locking load, infinite locking positions, short switching time, energy-efficient control, and a compact and lightweight structure. This paper aims at this open problem by presenting a novel piezoelectric (PZT) actuated lockable prismatic joint. This joint is a compliant mechanism (CM) consisting of a compound bridge-type compliant mechanism (CBCM) and a pair of compound multibeam parallelogram mechanisms (CMPMs). It can produce the required input/output stiffness to transmit large forces for high-load locking. It can also provide a desired input/output motion range for PZT actuation-based unlocking and for facilitating preloading adjustment. An analytical model is presented based on a compliance matrix method and the nonlinear model of the CMPM to predict the joint's static characteristics under various input/output conditions. A two-step optimization framework is proposed for locking applications. The theoretical study and nonlinear FEA/experimental verification confirm the feasibility of the design and the accuracy of the proposed model.
Compliant mechanisms , Lockable joints , Morphing structures , Parametric optimization , PZT actuation , Static modeling
Zhao, Y., Hao, G., Chai, L., Tian, Y. and Xi, F. (2022) 'A compliant-mechanism-based lockable prismatic joint for high-load morphing structures', Mechanism and Machine Theory, 178, 105083 (25pp). doi: 10.1016/j.mechmachtheory.2022.105083