Analysis of the terrestrial locomotion of a salamander robot

Salamanders propel themselves by proper coordination of limb movements and body undulations. This type of locomotion is interesting for robotics to design robots capable of locomotion on water and land. In this work we identify the control and structural parameters that contribute to forward terrestrial locomotion. We introduce a kinematic model of Salamandra robotica II, a new salamander robot, to explore how the stride length varies with different limb sizes and different types of body oscillations. We also perform systematic tests using a dynamic model built in a physics-based simulator to analyze the locomotion performance in terms of forward speed and power consumption. The results show that it is beneficial to use body undulations with variable curvature along the body, and that the tail can serve as a fifth limb to provide thrust on ground. Experiments using the real robot validate the simulation results and the contribution of the proposed control strategies.