Design of a Twisting Multi-stable Actuator

Actuators based on compliant multi-stable structures offer benefits of low mass, large stroke, high blocking force, and fast actuation response. The compliant structure eliminates friction and failure points inherent to actuators featuring joints and moving parts. These characteristics offer a large potential for application in fields such as aerospace or robotics where they can be scaled and modified to fit many design scenarios. A class of twisting bi-stable structures lends itself for use in linear actuation, as linear displacement is created upon twisting. These structures are also capable of fast actuation via snap-through between stable twisted states. This paper considers the application of a compliant bi-stable twisting structure as a linear actuator capable of bearing a load and producing a relatively large stroke length through actuation with smart material actuators. Finite element modeling is used for analysis, where a parameter study of the structure\u27s geometry is used to tailor equilibrium behavior, thus resulting in a useful stroke length from twisting of the compliant structure. The design is adapted to function with a polymeric material and a physical 3D printed prototype is constructed to demonstrate the compliant bi-stable linear actuator concept. Finally, two means of actuation are proposed to trigger snap-through of the compliant structure with smart material actuators. This unconventional design serves as a useful linear actuator that is relevant to aerospace applications as well as other applications where low complexity and versatile engineering structures are required