It is a long-standing interest of the robotics community to investigate actuators with performances matching or exceeding the ones of biological muscles. Currently, the majority of robots are still powered by stiff actuators, which do not exploit the unique soft properties of the muscle-tendon system. However, compliant/soft robotic features are promising for locomotion, manipulation or wearable robotics to reach expected performances and safety during interaction with humans or uncertain and dynamic environments.
Currently, a large class in soft robotics consist of soft pneumatic actuators (SPA), which are mostly constructed (almost) entirely out of soft, (hyper) elastic materials (Ecoflex®) and are, like the name indicates, actuated by compressed air. Because of these intrinic softness, SPAs have the ability to resist mechanical impacts that would irreversibly damage or destroy hard robotic systems. This is a very interesting feature, since these actuators will be used in next generation (soft) robots, which will function in unknown, unstructured and non-predefined environments; in other words, the world we are living in. They will be subjected to unexpected damaging conditions, such as impacts and collisions. The mechanical softness of the SPAs will protect them against these hostile events.
However, the use of SPAs introduces a new problem: the actuator parts can be easily ripped, perforated or scratched by sharp objects presented in hostile environments.
This problem can be solved by designing SPAs and compliant elements entirely out of self-healing (SH) polymers. Up till now, the self-healing material technology is not yet explored in robotics. Recent development in SH-polymers have led to (commercial) applications and made us investigate the potential of using these materials in robotics.