This thesis aims to cover some aspects of synthesis and design of Proportional- Integral-Derivative (PID) controllers. The topics include computer aided design of discrete time controllers, data-based design of discrete PID controllers and data- robust design of PID controllers. These topics are of paramount in control systems literature where a lot of stress is laid upon identification of plant and robust design. The computer aided design of discrete time controllers introduces a Graphical User Interface (GUI) based software. The controllers are: Proportional (P), Proportional-Derivative (PD),Proportional-Integral (PI) and Proportional-Integral- Derivative (PID) controllers. Different performance based design methods with these controllers have been introduced. The user can either explore the performance by interactively choosing controllers one by one from the entire set and visualizing its performance or specify some performance constraints and obtaining the resulting set. In data-based design, the thesis presents a way of designing PID controllers based on input-output data. Thus, the intermediate step of identification of model from data is removed, saving considerable effort. Moreover, the data required is step response data which is easier to obtain in case of discrete time system than frequency response data. Further, a GUI developed for interactive design is also described. In data-robust design, the problem of uncertainty in data is explored. The design method developed finds the stabilizing set which can robustly stabilize the plant with uncertainty. It has been put forward as an application to interval linear programming. The main results of this research include a new way of designing discrete time PID controllers directly from the data. The simulations further confirm the results. Robust design of PID controllers with data uncertainty has also been established. Additionally, as a part of this research, a GUI based software has been developed which is expected to be very beneficial to the designers in manufacturing, aerospace and petrochemical industries. PID controllers are widely used in the industry. Any progress in this field is well acknowledged both in the industry and the academia alike. This thesis attempts a small step further in this direction.

The main topic of this thesis is to exhibit how robust control techniques can be applied to real time systems. Presently, the control techniques used in the industry are very simple even when applied to complex systems; these techniques are intuitive and not necessarily systematic. Moreover, the notion of optimality of robustness is absent. Control design procedures are mostly based on SISO techniques, thus, overlooking the intrinsic multivariable aspect of the design that a MIMO system requires. In this thesis a modern control technique is presented to manipulate a 3DOF birotor helicopter in real time. The objective of this research is to demonstrate the performance of more efficient control algorithms to control these kinds of systems. The robust method proposed in this thesis is an H infinity controller which exhibits robustness to plant model uncertainties, and good disturbance and noise rejection.

In this paper we adopt a new technique combined with operator theorem to analysis linear time-varying system. This make us solve the robust control problems of linear time-varying system more easily. Also, we can apply this method to the problems of linear time-invarying system. First, we construct the operator we want to use, then apply it to the linear time-varying system. Moreover, we can apply this method to the structure singular value problem of robust control, and the result is similar with the linear time-invarying system. Then , we construct the standard control problem , and adopt linear matrix in- equality to get suboptimal controller to satisfy the robust performance we need. Finally,we use numerical method to discuss it.

This paper presents the research on the robust control of micromachined accelerometers. First, we present different micromaching techniques and compare, analyze the accelerometers with different methods of signal pick-off. Besides the different methods of signal pick-off(the position detection of the seismic mass) and structure designs, we can enhance the performance such as stability, bandwidth, sensitivity, resolution and dynamic range etc. by suitable feedback controllers. So inside the front part of the paper are the analyses for the controllers of different types of accelerometers so far. Moreover, we design the controllers by robust control in different methods with the model of one specific type of micromachined tunneling accelerometer. Because of the robust controllers, the accelerometers can be stable and have good performance under different environments and uncertainties. At last we analyze and compare the controllers designed by -synthesis and gap metric.

The purpose of this paper is to study the design of robust control for a flexible beam. First, the finite element method (FEM) is used to formulate the ordinary differential equations (ODEs) of the dynamic system of the beam model, and a controller is designed via the H-inf control theory. From the computer simulation results, the following conclusions could be drawn. 1. The developed controller is capable of precision positioning and tolerating external disturbance. 2. The robust stability for the system is assured. Furthermore, robust control of linear one-dimensional systems is extended here to two-dimensional systems. The finite difference method (FDM) is applied to partial differential equations (PDEs) to obtain the so-called Roesser discrete state-space model. We discussed the application of H¡Û control for two-dimensional systems and the design of H-inf controller is formulated into a convex optimization problem characterized by linear matrix inequalities (LMIs). Finally, the solutions of the LMIs are then used to construct a two-dimensional H¡Û controller.

This thesis aims to cover some aspects of synthesis and design of Proportional- Integral-Derivative (PID) controllers. The topics include computer aided design of discrete time controllers, data-based design of discrete PID controllers and data- robust design of PID controllers. These topics are of paramount in control systems literature where a lot of stress is laid upon identification of plant and robust design. The computer aided design of discrete time controllers introduces a Graphical User Interface (GUI) based software. The controllers are: Proportional (P), Proportional-Derivative (PD),Proportional-Integral (PI) and Proportional-Integral- Derivative (PID) controllers. Different performance based design methods with these controllers have been introduced. The user can either explore the performance by interactively choosing controllers one by one from the entire set and visualizing its performance or specify some performance constraints and obtaining the resulting set. In data-based design, the thesis presents a way of designing PID controllers based on input-output data. Thus, the intermediate step of identification of model from data is removed, saving considerable effort. Moreover, the data required is step response data which is easier to obtain in case of discrete time system than frequency response data. Further, a GUI developed for interactive design is also described. In data-robust design, the problem of uncertainty in data is explored. The design method developed finds the stabilizing set which can robustly stabilize the plant with uncertainty. It has been put forward as an application to interval linear programming. The main results of this research include a new way of designing discrete time PID controllers directly from the data. The simulations further confirm the results. Robust design of PID controllers with data uncertainty has also been established. Additionally, as a part of this research, a GUI based software has been developed which is expected to be very beneficial to the designers in manufacturing, aerospace and petrochemical industries. PID controllers are widely used in the industry. Any progress in this field is well acknowledged both in the industry and the academia alike. This thesis attempts a small step further in this direction.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 98-102). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (p. 126-129).

Power generation using wind turbines is a highly researched control field. Many control designs have been proposed based on continuous-time models like PI-control, or state observers with state feedback but without special regard to robustness to model uncertainties. The aim of this thesis was to design a robust digital controller for a wind turbine. The design was based on a discrete-time model in the polynomial framework that was derived from a continuous-time state-space model based on data from a real plant. A digital controller was then designed by interactive pole placement to satisfy bounds on sensitivity functions. As a result the controller eliminates steady state errors after a step response, gives sufficient damping by using dynamical feedback, tolerates changes in the dynamics to account for non linear effects, and avoids feedback of high frequency un modeled dynamics.

Over the last decade, considerable effort has been devoted to the implementation and analysis of self-tuning controllers on systems which are assumed to be represented exactly by linear dynamical models. In this thesis we examine the robustness of the self-tuning controller, when applied to systems consisting of a nominal linear plant which may have linear or nonlinear perturbations. Robust stability is the primary criterion and most of the results are for the Clarke-Gawthrop version of the self-tuning controller. Conditions are derived for the robust stability of the adaptively controlled system in terms of the design choices available to the engineer setting up the self-tuning controller. These are strong stability results in that they are in terms of both 1₂ and 1_∞ stability. The results are shown to be applicable to the general delay case and in the presence of non-zero mean disturbances. Preliminary results are also obtained for the robust stability of the explicit self-tuning controller.