Browsing by Subject "Process control -- Computer simulation"

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    Real-time process and control simulation
    (Texas Tech University, 1996-08) Shah, Deval Vipinchandra
    This work addresses the problem of easily developing a controller for a complex process. The development of the controller necessitates modeling and simulation of the process using a simulation language which helps reduce the gap between simulation studies and field realization. An example process, the flash tank chemical process, was chosen to make a comparison among the three common languages used for simulation, MATLAB, C and C++. The nonlinear practical process was simulated in these languages. An object-oriented model in C++ was developed for the process. The increased functionality of MATLAB with the use of the MATLAB Compiler and the C Math Library was explored for this process. It was found that a language for simulation should be chosen depending on the priorities in developing the controller. Due to a direct low level implementation, C language can help create more efficient code at the processor level. Due to a better representation of the process in the program, an object-oriented approach using C++ language can help in frequent modifications in the model of a process. However, the code in C or C++ can become lengthy and difficult to program. With the help of built-in functions in MATLAB, MATLAB can help reduce the time for developing a controller.
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    Statistical process control performance characterization under field conditions
    (Texas Tech University, 1997-05) Karim, Mehmud Zaglul
    Performance characterization of SPC technology is necessary in order to assess the impact of potential SPC strategies and actions. In this research a simulation-based tool (SPClab) is defined, designed and developed that can be used to study SPC options and its performance characteristics, considering both iid and non-iid data streams with and without step shifts in the data stream. The step shifts can be in location and/or in dispersion. The tool has three modules (1) simulation module, (2) performance module and (3) Output/report module and is developed using Borland C++ version 3.1. The number of programming lines needed to complete the tool is 20,019. The tool was tested and demonstrated in the cases of both iid and cyclical response data streams. The results from the simulation agree closely with those of theoretical values and other investigations found in the literature for the normally distributed iid case, indicating the tools validity. The tool, SPClab, was also used to demonstrate how to assess the impact of different SPC strategies and actions by considering different sampling scheme. The adverse consequences of applying SPC models inappropriately to non-iid data streams were illustrated. An appropriate physical-covariate based modeling approach is also introduced