Movement of insectomorphic robot by using unfixed balls

The question on design of the insectomorphic robot motion on unstable obstacles is investigated. It was solved in model formulation the problem on robot displacement from a horizontal plane at an unfixed ball, next rolling it up to the another unfixed ball, after that climbing onto another one and then climbing down onto horizontal plane. It was found theoretically that the vertical spin of the ball arises inevitably if the robot's center of mass is displaced in perpendicular to the ball's velocity plane from the axis passing through the center of the ball. This makes it difficult to maneuver the robot on the ball.