A Single-Actuated Swimming Robot: Design, Modelling, and Experiments

This paper describes and investigates a simple swimming mechanism, which comprises two concentric bodies and two passive flaps. The mechanism propels itself forward by oscillating its inner body in a symmetric fashion using a single actuator. Using a few assumptions, we develop a simplified model to investigate the dynamics of the robot and to simulate its motion. Numerical simulations show the effect of design parameters and control inputs on the locomotion performance. Next, we show how changing the control input from symmetric to asymmetric oscillations leads to a turning motion, still using only a single motor. By modulating the asymmetry in the oscillatory input, the turning radius changes. We conclude with a validation of our model with a proof-of-concept prototype showing similar swimming motions.