Force and Traction Controlled Propulsion of the Omnidirectional Wheeled Climbing Robot Cromsci

Climbing on vertical concrete structures like bridge pylons or dams is still a great challenge for autonomous robots. This paper presents the forceand traction control system of the climbing robot Cromsci which uses a negative pressure system for adhesion and driven wheels for propulsion. Especially in vertical environments the propulsion system must be able to produce enough force for carrying and accelerating the robot contrarily to gravity. Slippery of the wheels must be minimized due to abrasion and uncontrollable movements of the robotic system. This can be done by measuring upcoming forces and taking them into account for a traction control system (TCS). Another problem may occur because of slightly different wheel orientations which will result in increasing shear forces. We will show a control system to minimize these errors and experimental results which demonstrate its functionality.