The Research Of The Material Canister Temperature Control Of Injection Molding Machine Based On Nonlinear Separate Strategy

Nowadays, about 32 percent of plastic is manufactured by injection molding machine. During the melting process, reducing the fluctuation of material canister temperature and improving the precision of temperature control can greatly affects the quality and property of finished products. In order to improve the precision of temperature control of the material canister, the dynamic mathematic models of two heating sources which can greatly impact on the temperature of material canister have been established in this paper. The fuzzy self-adaptive PID controller and the diagonal matrix decoupling method are applied in the temperature control system. The simulation results demonstrate that the system reaches anticipative goal. The content is introduced as follows:Firstly, the article introduced the background of the research, the methods of material canister temperature control at home and abroad, and the temperature control indicators, and mainly discussed the impact of temperature fluctuation on the plastic product. The second chapter introduced the structure of temperature control system, analyzed the multi-heating-source characteristic of material canister. According to the measured temperature data, the mathematical models of three heaters coupling matrix transfer function has been established by experimental method and the mathematical model of friction-shear heating-source has been established by analytical method.In chapter three, the scheme of PID parameters self-tuning based on fuzzy control was proposed. Meanwhile a fuzzy rule table which has clear physical meaning was established and a new highly precise fuzzy self-adaptive PID controller was designed. Compared with traditional PID controller, the simulation results indicate that the fuzzy self-adaptive PID has a better performance in both dynamic and static state, and more robust. It can effectively improve the precision of temperature control by theory.In chapter four, we analyzed the strong coupling characteristic of temperature between two sections of material canister. In order to decouple the temperature-coupling, the diagonal matrix decoupling method was adopted in the temperature control system. The simulation results show that the method solved the temperature coupling among the sections. The nonlinear separation control of the sections temperature was achieved, and the precision of whole canister temperature control was greatly improved.In chapter five, we analyzed the drawback of hardware configuration. In order to eliminate the drawback of the hardware configuration, a digital variable-power heating device was developed. At last, the study contents and conclusions of this paper have been summarized, and the further research works have been forecasted.