Design approach for a compliant five-bar tristable mechanism

The compliant multistable mechanism is capable of steadily staying at several stable equilibrium positions without a power input, and has many applications in valves, switches, relays, and closures. In this paper, we propose a new idea of using the optimization algorithm to develop the compliant five-bar tristable mechanism: The compliant five-bar mechanism is modeled using a 1 degree of freedom pseudo-rigid-body model first. Then based on the least action principle, a constrained optimization routine is presented to determine the angular displacements of the three follower bars and the potential energy stored in the compliant five-bar mechanism. Finally, an objective function is proposed, which includes the number of the minima of the potential energy curve and the loop closure equations of the model, and an unconstrained optimization routine is described to develop a compliant five-bar tristable mechanism. The effectiveness of the idea is demonstrated by two prototypes. ©, 2015, Xi'an Dianzi Keji Daxue Xuebao/Journal of Xidian University. All right reserved.