Control of a snake robot in consideration of constraint force

This paper deals with an autonomous locomotion of a snakelike articulated robot with passive wheels. Using the non-slip condition of the wheels, the robot gains propulsion by means of constraint forces on the wheels caused by bending the joints. Our goal is to achieve the so-called serpentine movement known to be an effective gait on a flat ground with automatic gait generation, i.e., without giving any winding gait beforehand. We utilize a notion of manipulability to evaluate the locomotability and propose a controller capable of reducing the constraint forces. The results of simulations show that smooth winding motion is achieved.