Robust regulation of a flexible joint robot manipulator using singular perturbation approach

Robot manipulators can be modeled with a class of nonlinear systems. In this paper, we consider a class of nonlinear singularly perturbed systems, which are affine in fast states and inputs. First, using normal form equations, we eliminate the nonlinear part of the system matrix of equations of the reduced system and transform it to a linear diagonal form and design an H,, controller for a system with a lower order than the original one. The composite controller that is applied to the original singularly perturbed system, consists of this H. controller and a controller that is designed for the fast subsystem. The proposed method is applied to a single link flexible joint robot manipulator.