Kinematic Analysis and Odometry-Based Navigation of an Omnidirectional Wheeled Mobile Robot on Uneven Surfaces

Wheeled mobile robots, particularly omnidirectional wheeled mobile robots are widely employed for various applications in different environments, which might be subjected to unevenness and irregularities in practice. This type of robot must be able to fulfill its maneuvers kinematically to prevent disruptions due to unevenness in its navigation, still travelling desired paths. In this research, the motion of the mobile robot on uneven surfaces is investigated and its kinematic equations are revised to take the unevenness of surfaces into account, and its navigation and path tracking are studied. In this regard, the solution of real time updating the rotation matrix on the basis of Euler angles is proposed. To verify this algorithm, a procedure for obtaining Euler angles in the simulation is also presented and verified. In the experimental test, the Euler angles are calculated with the low-cost inertial sensors. Experimental tests are performed by an omnidirectional three-wheeled mobile robot on a laboratory uneven terrain specifically designed and built for this purpose. By employing this algorithm in the simulation, the positioning error caused by the unevenness of the surface was completely eliminated and the traveled path was matched with the desired path. In the experimental test, the improvement of the error of the path final point, was more than 83% and the improvement of the RMS error of all the points of the path was more than 77%.