Global Trajectory Tracking Control of a Four-Link Robot Manipulator without Velocity Measurements

This paper deals with the trajectory tracking control problem of a serial four-link manipulator in order to design a controller which globally stabilizes the desired motion of the robot without velocity measurements. We use the dynamic model of the manipulator described by Euler-Lagrange equations. The output position dynamic feedback controller has been proposed on the base of Lyapunov functions method. We exploit the periodicity property of the manipulator dynamic equations with respect to the rotational angles of the robot links. More precisely, we obtain the solution to the global trajectory tracking control problem in a cylindrical phase space. Global attractivity and uniform asymptotic stability properties of the closed-loop system are achieved. Simulation results are provided to show the quality of the controller.