Development and Control of a Small Biped Walking Robot Using Shape Memory Alloys

This paper presents a study on the development and control of a small biped walking robot using shape memory alloys (SMAs). We propose a flexible flat plate (FFP) consisting of a polyethylene plate and SMAs. Based on a detailed investigation of the properties of the SMA-based FFP structure, we develop a lightweight small walking robot incorporating multiple SMA-based FFPs. The walking robot has four degrees of freedom and is controlled by switching the ON-OFF current signals to the SMA-based FFPs. The switching timing, central to the control strategy to achieve walking behavior, is determined through experiments. The small robot realizes biped walking by transferring the elastic potential energy (generated by deflections of the SMA-based FFPs) to kinematic energy. The resulting small biped walking robot weighs a mere 2.8 g (with a height of 70 mm). Our experimental results demonstrate the viability and utility of the small walking robot with the proposed SMA-based FFPs and the control strategy to achieve walking behavior.