This thesis proposes an interactive software tool that can be used to compute complete sets of Proportional Integral Derivative (PID) Controllers from knowledge of the plant transfer function/frequency response data. This is based on research results and algorithms developed by Bhattacharyya and others. Until these research results were published, it was not known if a nominal system could be stabilized using PID Controllers, and current PID Controller designs are carried out using ad hoc tuning rules. By using simulations, engineers can best plan for and observe the stabilizing effect each of the variables has on system performance in a realistic environment. The software application developed calculates and optimizes complete stabilizing sets of PID Controllers for a rational Linear Time Invariant (LTI) system, and has been developed for analytical models of plants with and without time delay. Further, these PID Controller sets are optimized to project subsets simultaneously satisfying multiple performance index specifications. Sets of PID Controllers that stabilize a system are also calculated automatically from knowledge of the frequency response of the plant. It allows the user ease of design and the ability to customize the final solution while permitting full control over source parameters. This thesis includes an introduction to the algorithms that have been developed for plant stabilization, a complete description of the graphical user interface, the simulation of the algorithms performed using LabVIEW, and a summary of future work.

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 (M.S.)--Missouri University of Science and Technology, 2009. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 17, 2009) Includes bibliographical references (p. 53).

No description available.

Prompted by the desire to increase the industrial applicability range of self-tuning control, the objective of this work has been to extend the standard linear self-tuning framework to facilitate the design of self-tuning controllers for bilinear systems. Bilinear systems form a well structured class of non-linear systems within which linear systems coexist as a special subclass. They are, therefore, appropriate for modelling a wider range of processes and plant than the restrictive, yet convenient, linear model structures since such models are valid both within the linear subregion and beyond. In addition to extending the self-tuning framework for bilinear systems another significant contribution of the Thesis is the introduction of a cautious least squares estimation procedure which also enhances the existing linear self-tuning schemes.

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.

No description available.

Thesis (MEng)--University of South Australia, 1997

The thesis presents the development of force controller to maintain desired normal forces during a very stiff contact operation conducted in a Computer Numerical Control (CNC) machine. Force controller approach described in this thesis requires the accurate knowledge of the nominal tool path a priori. Obtaining the nominal tool path accurately is carried out by a vision based profile tracking system presented in this thesis. Both the force control and visual profile tracking systems require the development of an active control system to respond to force and vision signals. To facilitate the active control, a two-stage approach has been taken. The first stage is to bring the CNC machine under real-time control of an external computer. The second stage is the design of the active axis controller. This is achieved by adding sensor feedback loops to the external axis controller. The purpose of the active vision based profile tracking system is to automatically generate the tool path accurately. Emphasis is on combining low resolution vision with visual control of the precision CNC machine to attain the accuracy required for metal spinning. Combination of visual profile tracking and an edge detection method that gives sub-pixel accuracy were used to obtain the required tool path. A curvature detection algorithm was developed to identify segments of the tool path by assuming that the tool path consists of circular and straight line segments. The developed active force controller operates in a dynamic setup and is used to maintain tool forces at desired levels. The complete control system operates in a manner similar to reaction compensation and the force controller can be viewed as an integrating on-off controller with minimum integral wind-up effect. As a result, a direct dependency of the control efforts on error signals has been eliminated. In addition, the force controller brings in artificial damping that ensures the stability of the control system. To demonstrate the effect of the force controller, spun component qualities were assessed.

Thesis (M.S.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references (ℓ. 50-51)