Thermal processes generally contain nonlinearity and randomicity, and it is difficult to build the nonlinear models by the traditional method such as the transfer function, so the whole optimal control for thermal processes is impossible.

• 热工过程往往具有非线性和不确定性,用传统的描述热工过程动态数学模型的方法(如传统函数等)难以建立非线性模型,从而难于精确表达热工过程及实施整体优化控制。