The Design And Simulation Of Biaxially Oriented Polypropylene Film Thickness Controlling System

The thickness of the biaxially oriented polypropylene is affected by the quality of raw material, extrusion pressure, the temperature of the ram head, Tensile speedin the production line. The nonlinearity, time-variation, laggingness and complexity of the system make it obviously difficult to be designed. The technology is progressively developed overseas, but much inferior at home because of a later start and the blockade on it. Consequently, the prime production line mainly depends on import of complete set of equipment, which, however, not only sets barrier to improving the domestic ability to upgrade the technology, but also weakens the core competitiveness of related products and economic benefits. Thus, to develop biaxially oriented polypropylene controlling system for plastic film industry has become an urgent and important strategic task.The thesis begins with the motivation, research background and its contribution, followed by the structure and operation principle of the thickness controlling system for the biaxially oriented polypropylene and three related PID controllers. After enough investigation, a thickness controlling system for biaxially oriented polypropylene is designed and simulated based on MCGS and MATLAB. The last part is the conclusion of the study and the outlook. Three primary tasks here included are:(1)A thickness controlling system of the biaxially oriented polypropylene based on MCGS configuration software is designed.MCGS is a set of configuration software applied to the quick construct and production of the monitoring system of the host computer. It is capable of providing a complete programme for solving the problem in the project with its multiple functions of on-site data gathering, actual time data processing, warning, flow control and animation display. The thickness controlling system for the biaxially oriented polypropylene based on MCGS configuration software, is capable of seeting hardware interface, gathering of real time data, man-machine conversation as well as animation display of the performance of controlling system.(2) Using PID controller based on RBF neural network and the PID controller based on genetic algorithm, the optimizing control of the transverse thickness of polypropylene is achieved. In the production of the biaxially oriented polypropylene, the thickness controlling system is nonlinear, time-varying, lagging, the control of the transverse thickness being most complicated. The traditional PID controller can't set the ideal parameters owing to its tremendous overshoot, slow response and difficult on-line modification. PID controller based on neural RBF network and genetic algorithm helps finding out ideal parameters and promoting the effect of the control by self-study. Simulating result indicates that these two controllers overrun the traditional one with small overshoot, quick response and great adaptability.(3) The communication between MCGS and MATLAB is achieved by DDE Dynamic Data Exchange technology.The communication between MCGS and MATLAB is completed by Dynamic Data Exchange (DDE) technology. Moreover, the PID parameter calculated in MATLAB can be sent to MCGS, greatly enhancing the PID parameter setting function of the configuration software.To conclude, the controlling system of the biaxially oriented polypropylene, characterized by small overshoot, quick response and great adaptability can enormously impove the quality of polypropylene. Its easy operation, satisfactory visibility and maintainability are conducive to boosting China's competency of manufacturing complete production unit of polypropylene and proving its value.