Force Enhanced Multi-Twisted and Coiled Actuator and Its Application in Temperature Self-Adaptive Tensegrity Mechanisms

Twisted and coiled actuators (TCAs) are a type of thermal-driven actuator with high energy density and display the enormous application potential to drive soft robots. However, the existing soft robots driven by TCAs are scarce and can only realize the grabbing and creeping movement almost without load capacity. The main reason is that the TCA fabricated by traditional self-coiling method has low force and long thermal response time. Aiming to improve the output force of TCA, the fabrication and force enhancement principle of multitwisted and coiled actuators (MTCAs) are developed. Compared with the traditional single-twisted and coiled actuators, the output force of the MTCA can be increased to more than three times with the same fiber. The proposed MTCA with a mass of 0.1 g achieves deformations of 14.46% of its length under load of 1200 g. Besides, we expand the application field of the MTCA into the self-adaptive mechanisms. Two temperature self-adaptive tensegrity mechanisms with self-folded and self-upraised ability are designed and tested to further display the excellent performances of the MTCA. This article not only proposed the MTCA with significantly improved output force, but also promoted the application of the TCAs in temperature self-adaptive mechanisms.