Nonlinear control of mechanical and aerospace systems with flexible elements: Application to robotics

Abstract

Due to inherent nonlinearity, the control of mechanical systems dictates the use of nonlinear techniques; e.g., high angle maneuvers of the Hubble space telescope, the space shuttle, or the tracking control of high speed robotic manipulators. Also, the presence of unmodeled dynamics such as ignored flexibilities can have a destabilizing effect. This thesis involves the design of nonlinear tracking controllers for mechanical and aerospace systems. A new control design methodology is presented for systems containing flexible elements. The new approach deals with a very general representation of these systems; hence the results are applicable to a wide range of mechanical and aerospace problems. For illustration purposes, the results are applied to robotic manipulators with rigid and flexible joints. The controllers are designed using techniques of analytical dynamics, Lyapunov theory, and singular perturbation theory