In this article, a robust tracking control method is developed for omnidirectional mobile robots (OMRs) with uncertainties in the kinematics and dynamics. The kinematic and dynamic uncertainties that significantly degrade the OMR tracking control performance should be simultaneously compensated, which has not been achieved by the existing OMR tracking control methods. Therefore, the OMR dynamics containing the actuator dynamics and dynamic uncertainties are obtained by including the friction present in the OMR and are identified using a system identification method for the actual OMR system. The kinematic uncertainties present in the OMR kinematics are then derived unlike the existing studies that do not consider them. A sliding mode disturbance observer is proposed to estimate these kinematic uncertainties. A robust backstepping-like feedback linearization tracking controller using estimates of both the kinematic and dynamic uncertainties is also proposed to compensate for these uncertainties. The proposed method is validated through a stability analysis and simulation and experimental results using an actually implemented OMR system.
Manuscript received January 14, 2020; revised April 9, 2020; accepted May 23, 2020. Date of publication May 29, 2020; date of current version April 15, 2021. This work was supported in part by the Korea Electric Power Corporation under Grant R19XO01-21 and in part by the National Research Foundation of Korea grant funded by the Korea government (2020R1A2C101226111). Recommended by Technical Editor J. Yu and Senior Editor M. Basin. (Corresponding author: Dongkyoung Chwa.) Sangyoon Jeong is with Hyundai Robotics, Sungnam 13615, South Korea (e-mail: fnxmaktm@ajou.ac.kr).
