Structured Approach to Industrial Control System Design
The design of complex control systems for industrial processes is in general still based on experience and trial and error rather than on systematic process analysis and control system design. Typically control systems in the process industry comprise either single PID control loops with clear association of the process input and controlled signal or standard control schemes developed by intuition through the years (e.g. cascade control using an underlying flow control loop). Although many of these control schemes seem to work rather satisfactorily, in most major control systems several poorly tuned or switched off controllers are encountered leading to unsatisfactory process behaviour or manual operation of the process. The subject of this work is the development of a structured approach to industrial control system design which makes the potential of systematic process analysis and controller design methods developed by control theory available for industrial users with limited control experience. This aspect has been addressed within the collaboration research project between the University of Glamorgan and the Fachhochschule Hannover, of which the work presented in this thesis is a substantial part. Therefore, the ICACSD (Industrial Computer Aided Control System Design) scheme has been developed to allow the design of PID based control structures for nonlinear single- and multivariable processes that are as simple as possible and as good as required. Beyond this an industrial standardised controller design procedure for nonlinear and multivariable processes has been elaborated. For the validation of the proposed approach, a prototype control system design tool has been programmed, which can be integrated into the ICACSD scheme using a block-oriented simulation environment. The approach for industrial control system design presented shows the benefits of applying advanced control system design methods which are usable by industrial users when provided with an intuitive and usable graphical user interface. In order to validate the work the proposed control design procedure has been made accessible in the form of a software prototype with an economically designed graphical user interface allowing easy application of the developed methods. The prototype realisation for the Industrial Computer Aided Control (ICAC) toolbox supplies the new structured approach to control system design for industrial processes within a block-oriented simulation environment.
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