Actuation of bistable buckled beams with Macro-Fiber Composites

In this paper, we talk about compliant bistable mechanisms, a class of mechanical systems that benefit from both compliance, allowing easy fabrication at small scales, and bistability, which brings two passive and stable positions. These properties make them first-class candidates for micro-switches, but also several other robotics appliances. We focus on the actuation of a simple class of bistable mechanisms, the compressed bistable beams, using an innovative smart material, the MFC (for macro-fiber composite). This kind of bistable system is made of a buckled beam, while the MFC is a piezo-based actuator, which can accept large extension deflections (up to 0.5% with a piezo technology). We discuss the impact of the actuator position, and show that it has a major impact on the system response and the switching excitation level. This helps to build more powerful systems and/or reduce the actuator size.