On Semi-Global Output Position Feedback Trajectory Tracking Control of a Multi-Link Revolute Joined Robotic Manipulator

In this paper, we present the controller for a multi-link robot manipulator with revolute joints to solve the trajectory tracking problem using only position measurements. The controller has been obtained on the base of a nonlinear dynamic output feedback. To compensate the lack of joint velocities measurements, a simple first-order nonlinear filter based on the bounded function of position tracking errors is proposed. On the base of the Lyapunov function method it is shown that a desired trajectory is semi-globally attractive and uniformly asymptotically stable in a cylindrical phase space. The feedback control gains are selected by using simple algebraic inequalities. The proposed controller is implemented for a three-link robotic manipulator, and the results show that our control scheme requires simple computation procedures.