基于有界干扰Hammerstein 模型的化工过程的预测控制

为了控制一类由Hammerstein模型描述的合有输入约束和有界干扰的非线性化工过程,提出一种鲁棒预测控制策略.该策略分为两步,第一步考虑系统状态不可测的情况,对无约束受干扰的线性模型采用鲁棒输出反馈预测控制方法计算中间变量,其中为了处理干扰,采用二次有界技术设计出能够在线更新的估计误差集合的方法使得系统有界收敛.第二步通过中间变量求解非线性代数方程和采用解饱和的方法得到满足约束的实际控制输入.为了验证方法的有效性,对聚丙烯牌号切换过程进行控制仿真.结果 表明,应用本文的控制策略,不仅能够保证优化问题的递推可行性也能保证闭环系统的鲁棒稳定性.

Model Predictive Control for Chemical Process Based on Hammerstein Model with Bounded Disturbances

In order to control a class of nonlinear chemical process described by Hammerstein model subject to input constraints and bounded disturbances, a robust model predictive control (MPC) strategy consisting of two steps was proposed. In the first step, the case that the system state cannot be fully measurable was considered and the intermediate variable was determined by the robust output-feedback MPC method. To handle the disturbance, the quadratic boundedness technique was adopted to design the formula for updating the bound of the estimation error on-line so that the system was bounded convergence. In the second step, the actual control input with constraints satisfaction was obtained by a solving non-linear algebraic equation group and desaturation. The polypropylene multi-grade transition control was stimulated to illustrate the effectiveness of the approach. Results show that by applying the proposed two-step MPC, the recursive feasibility of the optimization problem and robust stability of the closed-loop system are both guaranteed.