Locomotion of an actinomorphic soft robot with soft composite structures

In this article, we present an actinomorphic soft robot with soft composite structures actuated by Shape Memory Alloy (SMA) wires. The composite structures act as arm function in the robot and incorporate soft materials, elastic plate and SMA wires. We analyze the relationship of frequency response of structures with the heating voltage and distance between PVC board and SMA wires. Based on resistance feedback of SMA wires, an adulation heating (AH) strategy was applied in composite structures. The strategy can adjust amplitude response of reciprocal motion of structures. Two kinds of rhythmic gaits were proposed for realizing the locomotion of the robot in different circumstances, e.g. circular undulation gait and horizontal undulation gait. The robot applied a hierarchical control system including a integral control layer to plan robot locomotion and several sub-control layers to control arm state. The maximum locomotion speed of the soft robot on flat ground was able to reach 140 mm/s in the air.