Digital control of a robot manipulator disturbed by unknown external forces

This paper addresses the problem of digital control of robot manipulators disturbed by unknown external forces. We present a new type of discrete-time robot model. The new model is characterized by its simple structure in which the nonlinear force term and external force term are eliminated. The control algorithms based on this model require no information about the external forces, thus they can be much simplified. Both pole placement control and adaptive control systems are designed. Experiments were carried out on a 2-link manipulator handing a cantilever-spring. The results verify the effectiveness of proposed model, and demonstrate the robustness of the designed system to unknown external forces