Accurate Robot Manipulator Control by Using a Model Reference Adaptive Control Method

There are many physical factors such as geometric nonlinearities, strong couplings, and the dependence on the inertia payload in the system dynamics of the robot manipulators which make it difficult to achieve good control performance. Furthermore, the end-effector of the manipulators provided by carrying various masses produces the undesirable motions in the all joints as well. Since it is generally difficult to describe the model and identify time varying physical parameters exactly, the conventional control methods cannot compensate the payload variation effect or uncertainties. In this study, the model reference adaptive controller (MRAC) is applied to robot manipulator control problem. In this study, the introduced control law does not require the exact system model. Despite its simplicity, the proposed control method provides excellent control performance over a wide range of manipulator motions and various payloads. Experiment results conducted on the 4-DOF robot manipulator demonstrate the practicality and feasibility of the proposed control scheme.