Analysis of Locomotion Trajectories of the Wheel-type Robot in a Straight Pipe.

Abstract

A mobile robot is difficult to move in a pipe in general, since the locomotional plane in a curved surface and the gravity direction operating on the robot are changeable. However, the wheel-type robot is able to locomote even in the curved pipe so that it can avoid an obstacle when an appropriate steering control is found. Also, the robot may locomote automatically by adjusting itself without the assist of an operator. This paper describes the analysis of the wheel-type robot's locomotion trajectories in pipe by using Ackermann-geometry expanded in three dimensions. At first the robot and the pipe are modeled for the analysis. Then the conventional Ackermann-geometry is expanded to become useful in three dimensions, and the method for calculating and estimating the trajectories is discussed. Later the locomotion in the straight pipe is simulated with the slimmed model of the wheel. Furthermore, the experiment to get actual locomotion trajectories is performed and the validity of the analysis is verified by comparing the analytical data with the experimental results.