Decentralized PD and robust nonlinear control of robot arms

A decentralized PD and robust nonlinear feedback law for robot motion control is proposed. The control system structure is based on the generalized tracking error proposed by Slotine-Li (1987). Using this system structure, we investigate the stability feature of PD control which has been widely employed by robot systems. A decentralized robust nonlinear feedback term is then added to it, which improves the specification of tracking errors from local convergence to global convergence and reduces the size of the residual set. Since the approach keeps the simplicity of the independent joint controller structure it can be easily implemented in most robot systems without hardware alteration