A Stability Analysis for the Acceleration-based Robust Position Control of Robot Manipulators via Disturbance Observer

This paper proposes a new nonlinear stability analysis for the acceleration-based robust position control of robot manipulators by using Disturbance Observer (DOb). It is shown that if the nominal inertia matrix is properly tuned in the design of DOb, then the position error asymptotically goes to zero in regulation control and is uniformly ultimately bounded in trajectory tracking control. As the bandwidth of DOb and the nominal inertia matrix are increased, the bound of error shrinks, i.e., the robust stability and performance of the position control system are improved. However, neither the bandwidth of DOb nor the nominal inertia matrix can be freely increased due to practical design constraints, e.g., the robust position controller becomes more noise sensitive when they are increased. The proposed stability analysis provides insights regarding the dynamic behavior of DOb-based robust motion control systems. It is theoretically and experimentally proved that non-diagonal elements of the nominal inertia matrix are useful to improve the stability and adjust the trade-off between the robustness and noise sensitivity. The validity of the proposal is verified by simulation and experimental results.Comment: 9 pages, 9 figures, Journa

Flat control of industrial robotic manipulators

Published ArticleA new approach to tracking control of industrial robot manipulators is presented in this paper. The highly coupled nonlinear dynamics of a six degrees of freedom (6-DOF) serial robot is decoupled by expressing its variables as a function of a flat output and a finite number of its derivatives. Hence the derivation of the flat output for the 6-DOF robot is presented. With the flat output, trajectories for each of the generalized coordinates are easily designed and open loop control is made possible. Using MATLAB/Simulink Sfunctions combined with the differential flatness property of the robot, trajectory tracking is carried out in closed loop by using a linear flat controller. The merit of this approach reduces the computational complexity of the robot dynamics by allowing online computation of a high order system at a lower computational cost. Using the same processor, the run time for tracking arbitrary trajectories is reduced significantly to about 10 s as compared to 30 min in the original study (Hoifodt, 2011). The design is taken further by including a Jacobian transformation for tracking of trajectories in cartesian space. Simulations using the ABB IRB140 industrial robot with full dynamics are used to validate the study

Wheeled Robot Slip Compensation For Trajectory Tracking Control Problem With Time-varying Reference Input

This paper presents the stability analysis of the closed-loop error dynamics obtained using an adaptive kinematic controller for the trajectory tracking control problem of a wheeled mobile robot with longitudinal slip. It is shown that the adaptive kinematic controller is able to compensate in real time for an unknown constant slip whenever the reference trajectory is generated by a slow time-varying reference input. This extends previous results found in the literature where the reference input is assumed to be constant. Moreover, it is also shown that the estimated slip parameters converges to their true values. Numerical results show the performance of the adaptive kinematic controller. © 2013 IEEE.167173Nourbakhsh, I.R., Siegwart, R., (2004) Introduction to Autonomous Mobile Robots, , London, UK: The MIT PressWang, D., Low, C.B., Modeling and analysis of skidding and slipping in wheeled mobile robots: Control design perspective (2008) IEEE Transactions on Robotics, 24 (3), pp. 676-687Dong, W., Control of uncertain wheeled mobile robots with slipping IEEE Conference on Decision and Control, Atlanta, USA, 2010Yoo, S.J., Adaptive tracking and obstacle avoidance for a class of mobile robots in the presence of unknown skidding and slipping (2011) IET Control Theory and Applications, 5 (14), pp. 1597-1608Ryu, J.-C., Agrawal, S.K., Differential flatness-based robust control of mobile robots in the presence of slip (2011) International Journal of Robotics Research, 30 (4), pp. 463-475Gonzales, R., Fiacchini, M., Alamo, T., Guzmán, J.L., Rodriguez, F., Adaptive control for a mobile robot under slip conditions using LMI-based approach Proceedings of the European Control Conference, Budapest, Hungary, 2009, pp. 1251-1256Zhou, B., Peng, Y., Han, J., UKF based estimation and tracking control of nonholonomic mobile robots with slipping IEEE International Conference on Robotics and Biomimetics, Sanya, China, 2007, pp. 2058-2063Iossaqui, J.G., Camino, J.F., Zampieri, D.E., Slip estimation using the unscented Kalman filter for the tracking control of mobile robots Proceedings of the 21st International Congress of Mechanical Engineering, Natal, Brazil, 2011Ward, C.C., Iagnemma, K., A dynamic-model-based wheel slip detector for mobile robots on outdoor terrain (2008) IEEE Transactions on Robotics, 24 (4), pp. 821-831Le, A.T., Rye, D.C., Durrant-Whyte, H.F., Estimation of track-soil interactions for autonomous tracked vehicles IEEE International Conference on Robotics and Automation, Albuquerque, New Mexico, 1997, pp. 1388-1393Michalek, M., Dutkiewicz, P., Kielczewski, M., Pazderski, D., Trajectory tracking for a mobile robot with skid-slip compensation in the vector-field-orientation control system (2009) International Journal of Applied Mathematics and Computer Science, 19 (4), pp. 547-559Song, Z., Zweiri, Y., Seneviratne, L.D., Althoefer, K., Non-linear observer for slip estimation of tracked vehicles (2008) Journal of Automobile Engineering, 222 (4), pp. 515-533Kim, D.-H., Oh, J.-H., Globally asymptotically stable tracking control of mobile robots Proceedings of the IEEE International Conference on Control Applications, Trieste, Italy, 1998, pp. 1297-1301Iossaqui, J.G., Camino, J.F., Zampieri, D.E., A nonlinear control design for tracked robots with longitudinal slip Proceedings of the 18th World Congress of the International Federation of Automatic Control, Milano, Italy, 2011Khalil, H.K., (2001) Nonlinear Systems, , Upper Saddle River, NJ, USA: Prentice-HallRosenbrock, H.H., The stability of linear time-dependent control systems (1963) Journal of Electronics and Control, 15 (1), pp. 73-80Gantmacher, F.R., (1960) The Theory of Matrices, , New York, NY, USA: Chelsea Pusblishing CompanyOriolo, G., Luca, A.D., Vendittelli, M., WMR control via dynamic feedback linearization: Design, implementation, and experimental validation (2002) IEEE Transactions on Control Systems Technology, 10 (6), pp. 835-85