In this article, the optimal operational control problem is considered for complex industrial processes with stochastic disturbances. The performance index is optimized by set points reselection on the operational control layer together with controllers design on the loop control layer. First, the operational indices are obtained through some optimization algorithms. Second, the controllers are designed in the ideal situation to ensure that the controlled variables can track desired set points. To minimize the performance deterioration caused by non-Gaussian stochastic noises or disturbances, a novel Pareto distribution estimation (Pareto DE)-based intelligent set-points reselection approach is proposed to optimize entropy and expectation simultaneously. In the proposed method, entropy is formulated in a recursive way basing on joint PDFs which are obtained through multivariate kernel density and bandwidth selection. Meanwhile, both the controller structure and controller parameters are fixed for whatever disturbances acting on the system. Finally, simulations are given to illustrate the effectiveness of the proposed strategy.
21 September 2018 in IET Control Theory & Applications
This study deals with optimal operational control problems using a novel approach where a performance index is optimised by controller design together with set‐points reselection. Firstly, the operational indices are obtained by employing some optimisation algorithms. The controller is then designed for each closed loop to ensure that the controlled variables can track the set points in the ideal situation. Taking advantage of disturbance observers, the set‐points are reselected dynamically to minimise the effect caused by unexpected noises or disturbances. In the proposed method, the controller structures or parameters are never changed no matter what kind of disturbance affects the whole system. Finally, two simulations are given to demonstrate the effectiveness and convenience of the proposed strategy.
In this paper, the fault detection in uncertain multivariate nonlinear non-Gaussian stochastic systems is further investigated. Entropy is introduced to characterize the stochastic behavior of the detection errors, and the entropy optimization principle is established for the fault detection problem. The principle is to maximize the entropies of the stochastic detection errors in the presence of faults and to minimize the entropies of the detection errors in the presence of disturbances. In order to calculate the entropies, the formulations of the joint probability density functions (JPDFs) of the stochastic errors are presented in terms of the known JPDFs of both the disturbances and the faults. By using the novel performance indexes and the formulations for the entropies of the detection errors, new fault detection design methods are provided for the considered multivariate nonlinear non-Gaussian plants. Finally, a simulation example is given to illustrate the efficiency of the proposed fault detection algorithm.
20 July 2017 in International Journal of Control, Automation, and Systems