Toward Self-Healing Actuators: A Preliminary Concept

Natural organisms have a unique property not yet available in robotics, i.e., a self-healing (SH) ability. This powerful biological healing function has inspired chemists to impart similar properties to synthetic materials to create “SH materials.” Recent developments in SH polymers led us to investigate the potential of using these materials in robotics. This paper presents an innovative approach of using SH polymers, based on the reversible Diels-Alder (DA) reaction, in a compliant actuator. Using DA polymers, a sacrificial SH mechanical fuse (SH-MF) is designed, developed, and validated by placing it in a cable-driven robotic system. The fuse is designed as weakest element and will sacrificially fail if a damaging overload occurs, protecting the compliant element and other components of the system. The experimental results showed that this SH-MF could be healed at a relatively low temperature, recovering the initial mechanical properties. This first working prototype indicates the feasibility to use SH materials in robotics. “SH robotics” will lead to more sustainable and lighter systems, and eventually to more efficient designs.