| Injection molding is a machine which can mould some product of some special shapes quickly. It contains four working process, melting, injecting, holding pressure and cooling. Injecting process is electro-hydraulic displacement servo control system, and holding pressure process is electro-hydraulic force servo control system. When system switch from injecting process to holding pressure process which is actual switching from electro-hydraulic displacement servo control system to electro-hydraulic force servo control system.Because of different mould pattern, elastic load is constantly changing in the holding pressure process, so system can't be described by accurate mathematics model. There maybe wallop when system switches from electro-hydraulic displacement servo control system to electro-hydraulic force servo control system. These are the features of Injection molding servo system, and also need to be solved in this paper.Based on this character, a method of fuzzy control will be used to apply the system parameter varieties in this paper. It is not necessary to build the system model for fuzzy control, and robustness of the system is good. However, because of fuzzy controller's lack, it can't have a good precision. So a control method of fuzzy adaptive control that absorbs the advantages of fuzzy control and adaptive control is used to ensure the control precision in the paper.Fuzzy adaptive control in this paper uses fuzzy model reference adaptive control, and it can provide the performance norm of the system. The parameters of the controller with the change of the controlled object can be continually modified during operation to maintain the tracking performance between system output and reference model output to improve control performance. Provided the reference model is stable, and the tracking performance is maintained, closed-loop stable control effect can be obtained. In this paper the constructing process and the principle of the fuzzy adaptivecontrol system are presented; The fuzzy controller is designed; A reference model is selected based on the system performance norm to build the fuzzy model reference control system, and the fuzzy adaptive control of injection molding electro-hydraulic servo system is accomplished; However, the simulation is done by Simulink toolbox of MATLAB, and compared with others. Finally, the experiments is undertaken to compare Fuzzy adaptive control and PID control by the experiments platform, and the control effect can be verified. The results of the simulation and the experiments obviously prove that the Fuzzy adaptive control can achieve the better control effect. |
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