Large Vertical Quench Furnace Temperature Of Distributed Parameter System Parameter Identification

Large-scale vertical quench furnace was a kind of critical equipment for thermal treatment of high-strength aluminum alloy components widely used in aerospace industry. According to characteristics of large-scale vertical quench furnac, the algorithm of parameter identification for temperature distributed parameter system was researched, and difficult quenching technics of large aerospace components was satisfied.Temperature was the key of large aerospace components' quenching thermal treatment technics. The structure of large-scale vertical quenching furnace was complex; many different types of heat transfer were combined; the components temperature in furnace could't be measured directly; temperature distribution was distributed parameter characteristically. It's very difficult to realize high precision and homogeneity of quench temperature control. Inaccurate parameters of control system will bring low temperature control precision and inappropriate temperature in furnace. If furnace temperature is too high the component will be overburnt, and if too low it won't satisfy the quality of components. Therefore, system parameters identification was required to get high precision and homogeneity of quench furnace temperature control and guarantee the quality of components.Orthogonal function approximation can assure the spatial distributed characteristic of distributed parameter model, and it also has many advantages, such as small calculation, high approximation precision, simple arithmetic and so on. Taking block pulse function as basic function and using orthogonal function transfer, the partial differential equation describing distributed parameter system control model was transferred to matrix algebra equation. On this basis the parameter on-line identification algorithm for temperature distributed parameter system of large-scale vertical quench furnace was deduced according to principle of Least Square. The identification considered the influence of initial condition and boundary condition, so the parameter identification precision was improved. Simulation experiments were carried on by MATLAB. After analyzing simulation result, characteristic of influence on parameter identification precision from space and time step was obtained. The simulation result indicated that this parameter estimation algorithm was effective, and it also kept the spatial distributed characteristic of system. The identification precision was within 8%. This method was easy to compute and could meet the demand of large-scale vertical quench furnace temperature distributed parameter control system on real-time and precision of parameter identification.