通过点集映射来表示非线性系统的稳态模型,用系统的稳态增益来修正具有外界输入的线性自回归(AutoRegressive with eXternal input,ARX)模型的动态增益,提出了一种基于稳态非线性模型和线性ARX模型组合的非线性预测控制算法.该算法用递归最小二乘法在线辨识系统的动态模型参数,用序列二次规划算法求解目标函数.最后通过对典型化工非线性对象pH中和过程的仿真对本算法进行了验证.结果表明,本算法比广义预测控制算法具有更好的设定值跟踪性能和抗干扰能力.
By representing the steady-state model of nonlinear system with a map of a set of numerical values and modulating the dynamic gains of ARX(AutoRegressive with eXternal input) model according to the system steady-state gains,a nonlinear model predictive control algorithm based on the combination of steady-state nonlinear model and linear ARX model is proposed.The algorithm carries out on-line identification of the system dynamic model parameters with recursive least square method and solves the objective function with sequential quadratic programming.Simulation is made in a representative nonlinear chemical process,i.e.,the pH neutralization process,to validate the presented algorithm,and the results demonstrate that the proposed method has a better performance in tracking set-point and restraining disturbance than the generalized predictive controller.