Using a planar snake robot as a robotic arm taking into account the lack of a fixed base: Feasible region

Snake robots are highly redundant robots that could potentially be used as robotic arms, allowing them to interact with the environment. However they do not have a fixed base, making them difficult to control accurately. In this paper, a complete modeling approach and an optimization algorithm are presented that show the torques that allow a snake robot to track a trajectory while keeping one of its links from slipping. To do this, it is essential to consider the static friction between the ground and a snake robot. The forces of static friction are modeled as bounded constraints, in a similar fashion as the constraint forces studied in grasping with robotic hands. Simulations are carried out to analyze the problem.