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随着社会工业的不断发展,在复杂的化工过程中越来越多地开始采用多速率控制系统,而采样周期是这种数字控制系统中的重要参数,对系统有着多方面的影响。目前基于采样周期的选取大多数是根据传统的实际经验来确定选取范围,还没有1种方法能够较准确的找到系统所需求的最适合的采样周期。本文针对一类多输入——多输出的系统,采用动态矩阵预测控制算法,通过建立1个简单的两输入——两输出系统的输入多速率模型,进一步推导出了多输入——多输出系统基于动态矩阵的通用输入多速率模型;采用经典的优化算法——遗传算法,对这种输入多速率下采样周期进行了优化选取,并针对一类双入双出的快慢耦合系统进行了仿真,在基本采样周期T一定的条件下,找到了使得系统控制性能最优的各个输入采样周期,得到最优控制效果(积分平方误差),对应的两个输入采样周期分别为基本采样周期的5倍和1倍,并将其与单速率下的控制性能进行了比较。结果表明,本文提出的这种方法可以有效的得到系统最优的采样周期,并且,对于这种病态耦合系统,在采样周期的适当选取下,输入多速率下系统的稳定性及综合控制性能优于单速率控制系统。
With the continuous development of social industry, multi-rate control systems are increasingly used in complex chemical processes. The sampling period is an important parameter in such a digital control system and has many impacts on the system. At present, the selection based on the sampling period is mostly based on the traditional practical experience to determine the selection range, there is no one method to more accurately find the system required for the most appropriate sampling period. In this paper, for a class of multiple-input-multiple-output systems, a dynamic matrix predictive control algorithm is adopted. By building a simple input-rate model with two inputs and two outputs, the multi-input-multiple output Based on the dynamic matrix universal input multi-rate model, the classical optimization algorithm-genetic algorithm is used to optimize the sampling cycle under multi-rate input. The simulation is carried out for a kind of fast-slow coupling system with double-input and double- Under certain conditions of the basic sampling period T, the input sampling periods that make the system control performance optimal are found, and the optimal control effect (integral square error) is found. The corresponding two input sampling periods are five times of the basic sampling period And 1 times, and compared with the control performance at a single rate. The results show that this method proposed in this paper can effectively obtain the optimal sampling period of the system, and for this kind of pathological coupling system, under the proper selection of sampling period, the stability and comprehensive control performance of the system under input multi-rate At a single rate control system.