A single-input state-switching building block harnessing internal instabilities

• Published in: Mechanism and machine theory 2024-06, Vol.196, p.105626, Article 105626
• Main Authors: ten Wolde, Malte A., Farhadi, Davood
• Format: Article
• Language: English
• Subjects: Bistable mechanism; Compliant mechanism; Elastic instability; Mechanical computing; State switching
• ISSN: 0094-114X; 1873-3999
• DOI: 10.1016/j.mechmachtheory.2024.105626

Bistable mechanisms are prevalent across a broad spectrum of applications due to their ability to maintain two distinct stable states. Their energy consumption is predominantly confined to the process of state transitions, thereby enhancing their efficiency. However, the transition often requires two distinct digital inputs, implicating the requirement of multiple actuators. Here, we propose an elastic and contactless design strategy for inducing state transitions in bistable mechanisms, requiring only a single digital input. The strategy leverages internal information, interpreted as system state, as an extra input to make a weighted decision for transitioning to the subsequent state. We characterize the behavior using a spring-based rigid-body model, consisting of a column near bifurcation, combined with a non-linear spring connected to a bistable element that represents the information state. The results show that a nonlinear spring with a quadratic stiffness function, i.e., representing internal instability, is crucial for regulating state-switching behavior. We then demonstrate this design strategy by developing a monolithic and compliant design embodiment and experimentally evaluate its behavior. [Display omitted] •Design method for state switching in bistable mechanisms with a single digital input.•Quadratic stiffness was identified as key to state-switching behavior.•Developed and experimentally validated a compliant design for state-switching.