Design of the affine nonlinear temperature-humidity controller in champignon-drying machine using heat and solar energies

The demand of the dried champignons increases year by year. The grades and the quality of the champignons have close relation to the drying process, such as drying methods, drying time, temperature, humidity, air-flowing and so on. The changes of temperature and humidity in drying machine are not simple linear but complicated nonlinear. The accurate process control is the key that influences the quality of the dried champignons. The dynamic mathematical models of the temperature, humidity and air-flowing in the drying machine in details are analyzed in this paper. The nonlinear theories and methods to analyze and control these small-environment elements are used and a kind of nonlinear controller is designed, which satisfied the optimal quadratic performance index. At last the controller is proved, which is feasible and practical through the simulating with MATLAB.