| This Ph.D dissertation describes the design and implementation of various control strategies centered around the following applications: (i) Adaptive Tracking Control of Linear Uncertain Mechanical Systems Subjected to Unknown Sinusoidal Disturbance, (ii) Task-Space Tracking Control of Robot Manipulators via Quaternion Feedback, (iii) A Continuous Asymptotic Tracking Control Strategy for Uncertain Multi-Input Nonlinear Systems and (iv) Output Feedback Variable Structure Control of Nonlinear Mechanical Systems. The theory developed in each of these sections is demonstrated through simulation results. An introduction to each of these four primary chapters can be found in Chapter 1.; The dissertation is organized as follows. In Chapter 2, the design and implementation of an adaptive disturbance rejection approach is presented for single-input-single-output (SISO) linear-time-invariant (LTI) uncertain mechanical systems subject to sinusoidal disturbances with unknown amplitudes and frequencies. The proposed technique suggests construction of a set of stabilizing tuning functions via a state estimate observer in a backstepping fashion to achieve asymptotic disturbance rejection. The tuning functions design is based on a single Lyapunov function incorporating both the error states and update law, and hence, global stability and improved transient performance are readily achieved. Utilizing only the system output, a virtual control input is used in place of non-measurable and unknown signals. The performance of the adaptation algorithm is demonstrated through both simulations and experiments for a single-degree-of-freedom (SDOF) system with unknown parameters and subject to an unknown sinusoidal disturbance. Significant matching between the simulation and experimental results is observed.; In Chapter 3, we consider the problem of task-space tracking control of robot manipulators. Based on a quaternion representation of the end-effector orientation, we design a class of task-space controllers that ensure asymptotic end-effector position and orientation tracking.; In Chapter 4, we present a novel continuous control mechanism that compensates for uncertainty in a class of high-order, multi-input nonlinear systems.; In Chapter 5, we develop a new output feedback, variable structure-like (discontinuous) tracking controller for a class of uncertain, multi-input multi-output, nonlinear mechanical systems whose dynamics are first-order differentiable. (Abstract shortened by UMI.)... |
