Summary
Compared to traditional robotic systems, small-scale robots, ranging from several millimetres to micrometres in size, are capable of reaching narrower and vulnerable regions with minimal damage. However, conventional small-scale robots’ limited maneuverability and controlability hinder their ability to effectively navigate in the intricate environments, such as the gastrointestinal tract. Self-propelled capsule robots driven by vibrations and impacts emerge as a promising solution, holding the potentials to enhance diagnostic accuracy, enable targeted drug delivery, and alleviate patient discomfort during gastrointestinal endoscopic procedures. This paper builds upon our previous work on vibro-impact capsule robots, exploring the potential of nonlinear connecting springs to enhance its propulsion capabilities. Leveraging a recently developed mathematical model for vibro-impact capsule robots with a von Mises truss spring, we investigate the effects of negative stiffness and snap-back within the nonlinear structural spring on the robots’ propelling performance. By leveraging the negative stiffness of the von Mises truss, the capsule robot achieves a remarkably wider operational bandwidth for propelling speed compared to its linear counterpart. Within this band, the robot maintains a significantly higher average speed, enabling more efficient and robust locomotion. This work sheds light on the potential for integrating customised nonlinear structures with small-scale robots to tailor their dynamic performance, thereby unlocking new possibilities for enhanced functionality and maneuverability in diverse biomedical applications.
