A vibrating mechanism for large amplitude, non-reciprocal motion, exploiting multiple buckling modes

A bi-stable mechanism capable of generating non-reciprocal motion is presented. This mechanism can efficiently generate a wave-like non-reciprocal trajectory with large amplitudes, using a single actuator, without feedback control. By optimizing the mechanisms topology, and thus the potential energy surface, a natural support for non-reciprocal motion is obtained. The task of generating a non-reciprocal motion in an efficient manner, often involves several actuators, sensors, and closed loop control. In this work, the non-reciprocal motion is obtained by making the mechanism to continuously alternate between stable and unstable buckling modes. The desired motion path is designed by optimizing the mechanism's total potential energy map. By tailoring the dynamic motion of a single actuator to the obtained potential map, two degrees of freedom and a non-reciprocal trajectory can be formed. A theoretical model describing the dynamical behavior was developed and investigated and it shows good agreement with an experimental system. It is demonstrated by simulation and experiment that by shaping the potential map and stable configurations, non-reciprocal as well as other types of complex motions can be generated. This mechanism can potentially serve as a multi-stable actuator or as a robotic limb where non-reciprocal motions are preferred.