Accurate 3D position control of articulated manipulators

Robot manipulators are complex nonlinear dynamic systems. Therefore, various control schemes were adopted to achieve accurate and repeatable motion control. To maintain an accurate position of the forearm when the articulated manipulator moves from a point to point in its workspace, a robust torque control law is required. In this paper, a modified robust single parameter control law is developed to obtain an accurate 3D Cartesian coordinate motion control. The position errors and the maximum torques are related to the controller parameter such that the optimum value of this parameter can be determined. Two cases have been considered, the exact case of certainty and the case of parameter uncertainty. A Matlab program is executed to simulate the manipulator dynamics, as well as to compute and analyze the position accuracy.