MODELING AND DESIGNING OF A NONLINEAR TEMPERATURE-HUMIDITY CONTROLLER USING IN MUSHROOM- DRYING MACHINE

摘要

Drying-process of many kinds of farm produce in a close room, such asmushroom-drying machine, is generally a complicated nonlinear and time-delay cause, in which the temperature and the humidity are the main controlled elements. The accurate controlling of the temperature and humidity is always an interesting problem. It's difficult and very important to make a more accurate mathematical model about the varying of the two. A math model was put forward after considering many aspects and analyzing the actual working circumstance in this paper. Form the model it can be seen that the changes of temperature and humidity in drying machine are not simple linear but an affine nonlinear process. Controlling the process exactly is the key that influences the quality of the dried mushroom. In this paper, the differential geometry theories and methods are used to analyze and solve the model of these small-environment elements. And at last a kind of nonlinear controller which satisfied the optimal quadratic performance index is designed. It can be proved more feasible and practical than the conventional controlling.