How to Improve Positional Accuracy in Redundant Omnid irectional Mobile Robot s ?

Non-systematic errors in wheeled mobile robots are significantly influenced by irregularities on the surface. The presence of non-smoothness on a surface causes the robot to deviate from its desired trajectory, and move towards an undesirable destination. This paper uses a technique, previously proposed by the first author, to alleviate the positional error originating from non-systematic resources during movement of a redundant omnidirectional wheeled mobile robot (OWMR). Kinematic equations of OWMRs form the foundation of this method to help us correct the robot motion, and reduce the errors occurring due to unwanted resources. To correct positioning errors, the expected surface on which the robot will be programmed to move is simulated. Afterward, a platform is fabricated having similar irregularities pattern. The robot is then programmed to travel on the designed platform and passes over designed obstacles. Two factors are obtained using experimental results: longitudinal and lateral. Both factors are then applied to the robot program. Then robot is finally tested on the same platform, and its motion accuracy is compared with the one obtained before applying the calibration factors. For studied case in this paper, nonsystematic positional errors are reduced at least 80% that is a reasonable accuracy improvement. Keywords—Positional error; non-systematic error; wheeled mobile robot; omnidirectional wheel; kinematics.