Nonlinear Robust Stability Tracking Control Design For A Robot System

Robot system is a high nonlinear system with very complicated time-varied, strong-coupled characters. One of the dynamic control aims is to make the positions and orientations of every joints and end effectors track given trajectories with ideal dynamic performance. In practical engineering, there are lots of uncertain factors, such as parameter errors, unmodelled dynamics, observer yawps, frictions, payload change, and uncertain external disturbances. So, it is difficult to derive the precise robot model. In recent ten years, the robustness about how to design controllers for robots, without depending on uncertainties, to reach the desired performance is a hot question. In addition, with the improvement of engineering technique levels, it will become one of important research tasks on interconnected robot system.In the paper, there are some preliminary research on the uncertain parameters and structures of interconnected robotic model in the trajectory tracking. Several effective control strategies are presented. The main contents are shown as follows:First. According to the Lyapunov method, a nonlinear robust tracking controller is proposed for a class uncertain interconnected robot system. The controller can guarantee that position vector and velocity vector of interconnected robot systems track the given trajectory asymptotically.Second. This paper investigates the robust trajectory tracking strategies for a class of interconnected robot systems with uncertainties. Based on the continuous known bounded functions of uncertainties and Lyapunov method, the decentralized robust controllers are proposed. The controllers can guarantee that the position vectors and velocity vectors of interconnected robot systems can track the given trajectory asymptotically.Third. A decentralized robust adaptive control scheme for a class interconnected robot system with modeling uncertain and exterior disturbances. The proposed controller is a composition of general linear controller, linear adaptive controller and nonlinear adaptive controller. It is proved by Lyapunov theories that the controller is capable of overcoming the uncertain effect effectively and realizing the trajectory tracking asymptotically to the closed-loop systems.All the research results above not only are proved strictly and carefully in theories, but are shown effectively and correctly by the given examples in this paper.