Granulating temperature is one of most important parameters of modern material bathing system, and must be controlled in certain range. But it has large lag, nonlinearity and parameters' time -varying characteristics, so the conventional Smith predictor can not satisfy performance requirements. In view of this problem, this paper presents a kind of IMC -Smith controller, in which, Smith predictor is modified by internal model control principles through equivalent transformation. The main controller is derived by IMC principle and integral square error criterion. Simulations in both model match and model mismatch situations of granulating system, using presented method, are carried out by MATLAB, the result shows that the performance of this control method is better than that of the conventional Smith predictor. Thus the validity of this project is proved.%制粒机调质温度是现代饲料生产过程中的重要参数之一,必须控制在最佳值附近.而调质温度被控对象具有大时滞,非线性以及参数时变的特性.传统的Smith预估器难以取得良好的控制效果.针对上述问题,提出一种IMC-Smith预估控制算法,算法将Smith预估器与内模控制相结合,采用内模控制原理和积分平方差指标设计给定点追踪控制器.在Matlab平台上对IMC-Smith控制算法进行模型匹配和模型失配的仿真,仿真结果表明控制系统性能较常规Smith预估控制有较大的提高,证明了控制方案的有效性.
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