Research Of Temperautre Control System On The Process Of Nozzle Mould Pressing

With the development of composite molding process, glass fibrous composite is not only widely used in civilian industry, but also becomes the important engineering material in aerospace industry. Although composites share smaller in aerospace, most of them are advanced composite, reveal the advanced technology of composite. In aerospace, composite is mainly used in insulation shell structure of the solid rocket engine's combustion chamber, the missile and satellite dome structure, heat-resistant materials of missile and structures of satellite. So advanced composite material's molding technology directly relates to the aerospace industry.In the existing process of nozzle molding with mould pressing, there are such problems: temperature uniformity of the overall nozzle is poor, process of control is highly affected by outside interference, the manufacture preparation is long, and the quality of finished product is poor, therefore the thesis deeply researchs on the process of nozzle mould pressing. In accordance with the requirements of existing technology and equipments , author designs the solution , has simulated the actual effect of the scheme , the simulation results is fully satisfied with the technologic requirements.In this paper, author first uses the finite element software ANSYS10.0 to model the heating system of nozzle mold, on the basis, the requirements of heating rate and uniformity of nozzle temperature are taken into consideration, simulates the transient temperature filed of the existing heating system, and analyses the drawbacks of the existing heating system. The analytical results consist with the current production basically.Aiming at the drawbacks of the existing control system, the thesis designs the improved heating system, replaces the existing three coupling controllers with a single controller. Ensuring the precondition of maximum heating rate, through the rational allocated with heating load on different surfaces, the thesis ensures the uniformity temperature of the mold's surface, satisfies with technologic requirements. On the basis, using the time history post procession of ANSYS to analyse the improved heating system, mathematics modeling of the system is obtained, which provides the analytic basis for the follow-up section.The thesis makes deep study into the theory and control mode of the system. By changing the existing way of intermittent heating to regulating the continuous quantity of heat, the control accuracy is greatly improved. The scheme is feasible in practice. On the basis, using MATLAB / Simulink software, the PID control diagram of nozzle molding temperature control system is established and the control effect of the traditional PID is simulated.Due to the particularity of nozzle mould pressing molding temperaturesystem, such as the variational parameters of the system in the process of control,reaction heat in the molding process, outside interference greatly affecting thesystem, big inertia and pure lag characteristics of the system, the effect of thetraditional PID control is not ideal. The paper designs the fuzzy controller of thenozzle temperature control with mould pressing, and simulates the control effectof fuzzy controller.The simulation effect indicates that fuzzy controller has thedrawbacks of frequent jitter at error±0.5℃and poor performance at the phasesof heat-insulation. To improve the control accuracy and response velocity,combining the merit of fast response with fuzzy controller and hign precision atsteady state with PID controller, the thesis further studyies on the fuzzyparameter self-adjusting PID for the process of nozzle molding with mouldpressing, uses fuzzy parameters self-adjusting PID controller to simulate thesystem, and achieves error±0.15℃without interference. System performanceof fuzzy parameter self-adjusting PID is better than PID controller and fuzzycontroller with interference, satisfies with the temperature control fasterresponse, smaller overshoot, higher steady accuracy requirements of the nozzlemolding process.