Cranking along: slip-free locomotion by snake robots without torsion-free joints

Although snake robots are probably most at their kinematic advantage in rough terrain, they should also be able to transport themselves efficiently over relatively smooth areas. An argument that is often held against them is that there is a heavy efficiency penalty for locomotion on flat surfaces, due to the energy loss caused by sliding friction of the robot´s body against the ground. An earlier proposed slip-free method, side-winding, requires advanced control. Another method, rolling, requires torsion-free joints. Here, we generalise the latter method to include snake robots,with non torsion-free joints, without great complication of control