Body shape and orientation control for locomotion of biologically-inspired snake robots

This paper considers guidance-based motion control of planar snake robots using a dynamic feedback control law. We first present the Euler-Lagrange equations of motion of the robot. Subsequently, we introduce a dynamic feedback control law for the joints of the robot to track a desired gait pattern. This tracking control law depends on the time evolution of the state variables of a dynamic compensator which is used for controlling the orientation of the robot. In particular, we employ the dynamic compensator to practically stabilize a reference head angle defined by a Line-of-Sight path following guidance law. Using an input-output stability analysis, we show the uniform boundedness of the solutions of the controlled system. Furthermore, we use a perturbation analysis to show that the orientation error is ultimately bounded by an arbitrarily small bound. Simulation results are presented to validate the theoretical results.