Disturbance observer based boundary control of a flexible manipulator with input saturation

In this study, we consider anti-windup design as one of the approaches for the boundary control problem of a flexible manipulator subject to input saturation and input disturbances. The dynamics of the system are represented by partial differential equation (PDE). One of the key contributions of this study is that using singular perturbation approach the PDE model is divided into two simpler subsystems and a disturbance observer with exponential error convergence is proposed. In addition, based on the disturbance observer and decoupled PDE model, a boundary control scheme is designed to regulate angular position and suppress elastic vibration simultaneously. The proposed control scheme allows the application of smooth hyperbolic functions which satisfy physical conditions and input restrictions can easily be realized. Numerical simulations demonstrate the effectiveness of the proposed scheme.