Development of self-healing linear actuator unit using thermoplastic resin*

High operational continuity in robots requires considerable ongoing manual maintenance, which can be replaced by enabling robots to self-heal. Extensive research on self-healing has been carried out toward the realization of this notion. The introduction of self-healing methods into mechanical systems has been investigated in recent years. However, these studies have been inadequate in terms of usage environment and self-healing efficiency. Therefore, in this work, we developed a self-healing actuator unit that can be applied to conventional mechanical systems by incorporating self-healing ability using a thermoplastic resin inserted at the actuator location. First, thermal simulation was performed to understand the design requirements to reduce healing time and ensure stable self-healing efficiency. Subsequently, experiments were performed with an actual machine, in which self-healing was consecutively carried out four times, resulting in an average self-healing efficiency of 110% and a maximum self-healing efficiency of 115%. These results show that it is possible to carry out healing without any reduction in the fracture strength of the healing mechanism, depending on the healing conditions and the designs of the parts in contact with the thermoplastic resin.