An earthworm-like micro robot using shape memory alloy actuator

A novel bio-mimetic micro robot with wireless control and wireless power supply using shape memory alloy (SMA) actuator is developed. There have been many kinds of mobile micro robot using the micro actuators such as ionic polymer metal composite (IPMC), micro motors and piezo actuators. These actuators generally require electric cable for power supply, which might highly influence the mobility of the micro robot. Therefore, a perfect wireless micro robot comprising telemetry and batteries is realized using only one SMA spring actuator and one silicone bellow. The SMA actuator and bellow play a role in contraction and extension of an earthworm muscle respectively. Based on theoretical analysis, specifications of a SMA actuator and a bellow are properly selected. For temporal stopping, setae of earthworm mimicked claws are employed. On the issue of control, the proposed robot is controlled according to On/Off signal via wireless communication. The operation is customized through tuning of on-/off-time of an actuator and using different type batteries such as a lithium, silver oxide and alkaline battery. After the design and experiment, we find out that the earthworm-like micro robot without wired power supply and control can move freely without limitation of working space and be fabricated easily.