Gait Design and Foot Trajectory Planning for a Wall-Climbing Robot with Spiny Toes.

This paper proposes a foot trajectory planning strategy for a wall-climbing robot (WCR) by introducing a detaching angle, a pause and a backswing movement of spiny toes into the locomotion, allowing easy detachment of the spines and the surface. Foot placement positions are found and optimized via an off-line search algorithm which yields the most body motion for per period with stable locomotion. Relevant coordinates and joint angles are obtained from the forward and the inverse kinematics through the screw theory. Furthermore, the gait is designed for the forward motion and the backward motion based on a quadrupedal trot, with a phase difference to assure a full contact of the feet with the wall. Results of the experiments reveal that the prototype WCR implemented with the planning of the gait and the foot trajectories can achieve speeds up to 125 mm/s on a vertical rough wall with stable forward and backward locomotion.