Fuzzy decoupling predictive functional control for nonlinear hydro-turbine governing systems with mechanical time delay of the hydraulic servo system

This study presents fuzzy decoupling predictive functional control for nonlinear hydro-turbine governing systems with time delay and strong coupling. Here, the Takagi–Sugeno fuzzy approach and fuzzy neural network decoupling algorithm are implemented in the pretreatment of a four-dimensional time delay hydro-turbine governing system model, aiming to solve the nonlinearity and separate coupling variables of the hydro-turbine governing system effectively. Then, a new fuzzy decoupling predictive functional control strategy proposed by combining the simplified hydro-turbine governing system model and predictive function control as well as the robustness and stability of the designed controller are verified by theoretical derivation. Numerical experiment demonstrates effectiveness and superiority of the proposed approach in comparison with fuzzy control under different operation conditions.

Adaptive Predictive Functional Control of X-Y Pedestal for LEO Satellite Tracking Using Laguerre Functions

In this paper, Predictive Functional Control (PFC) is used for X-Y pedestal control for LEO satellite tracking. According to the nonlinear characteristics of the X-Y pedestal and pedestal model variation caused by its operating point change, the use of system identification algorithm, which is based on special types of orthonormal functions known as Laguerre functions, is presented. This algorithm is combined with PFC to obtain a novel adaptive control algorithm entitled Adaptive Predictive Functional Control (APFC). In this combination, Laguerre functions are utilized for system identification, while the PFC is the control law. An interesting feature of the proposed algorithm is its desirable performance against the interference effect of channel X and channel Y. The proposed APFC algorithm is compared with Proportional Integral Derivative (PID) controller using simulation results. The results confirm that the proposed controller improves the performance in terms of the pedestal model variations; that is, the controller is capable of adapting to the model changes desirably.

CONTROL SYSTEM SYNTHESIS FOR THE ETHYLBENZENE DEHYDROGENATION PROCESS BASED ON THE PREDICTIVE FUNCTIONAL CONTROL METHOD

Описывается применение метода предиктивного управления при синтезе автоматизированной системы программного управления производством стирола. На основе результатов системного анализа объекта управления обоснован способ управления технологическим процессом, проведены обзор и оценка возможности использования различных видов регулирующих устройств. В рамках концепции модельно-ориентированного проектирования синтезирована автоматизированная система, реализующая предсказательное функциональное управление (Predictive functional control (PFC)) концентрацией стирола на выходе из первой ступени реакторного блока. Выполнен структурный синтез и разработан алгоритм функционирования управляющей системы. В качестве структурного элемента, выполняющего построение прогнозной траектории изменения управляющего и управляемого параметров, использован комплекс динамических моделей, описывающих теплообменные процессы и физико-химические превращения, протекающие в исследуемой системе. Расчет оптимального значения управляющего воздействия производился с учетом инерционности технологического оборудования, параметров состояния каталитического слоя реактора, энергетических потоков и компонентов реакционной среды в соответствии со сформированным комплексным интегральным критерием энергоэффективности процесса при одновременном обеспечении максимальной производительности. Приведен сравнительный анализ результатов расчета переходных процессов по основному каналу системы управления, полученных при использовании регулятора ПИД-структуры и управляющего устройства, реализующего метод PFC-управления The article describes the application of the predictive control method in the synthesis of an automated system for software control of styrene production. Based on the results of the object system analysis, the method of process control is justified, the review and evaluation of the possibility of using various types of control devices is carried out. Within the framework of the model-oriented design concept, an automated system is synthesized that implements predictive functional control (PFC) of the concentration of styrene at the outlet of the reactor unit first stage. A structural synthesis was performed, and the control system operation algorithm was developed. A set of dynamic models describing heat exchange processes and physical and chemical transformations occurring in the system under study is used as a structural element that performs the construction of a predictive trajectory of changes in the controlling and controlled parameters. The calculation of the optimal value of the control action was carried out taking into account the inertia of the process equipment, the parameters of the state of the catalytic layer of the reactor, energy flows and components of the reaction medium in accordance with the formed complex integral criterion of the energy efficiency of the process while ensuring maximum productivity. A comparative analysis of the results of calculating transient processes for the main channel of the control system, obtained using a PID structure controller and a control device that implements the PFC control method

IMPROVED CONSTRAINT HANDLING APPROACH FOR PREDICTIVE FUNCTIONAL CONTROL USING AN IMPLIED CLOSED-LOOP PREDICTION

Predictive Functional Control is a simple alternative to the traditional PID controller which has the capability to handle process constraints more systematically. Nevertheless, the most basic form of PFC has suffered from ill-posed prediction due to its simplicity in formulation and assumption of constant future input dynamics. Although some constraints can be satisfied, nevertheless the performance may be very conservative due to this issue. The main objective of this paper is to improve the constrained performance of a PFC controller with a minimum modification of the existing formulation. Specifically, a novel constraint handling approach for PFC is proposed based on an implied closed-loop prediction. Instead of assuming a constant input as deployed in the conventional open-loop prediction, the implied closed-loop input dynamics are utilised to detect future constraint violations. In addition, a future perturbation is introduced into the prediction structure as an extra degree of freedom for satisfying the constraints. Two simulation results confirm that the proposed approach gives far less conservative constraint handling and thus better control performance compared to the nominal PFC. Furthermore, this novel implementation also alleviates the well-known tuning difficulties and prediction inconsistency issues that are associated with conventional PFC when handling constraints. ABSTRAK: Kawalan Kefungsian Ramalan adalah alternatif mudah kepada kawalan tradisional PID yang mempunyai kekangan keupayaan bagi mengawal proses secara lebih tersusun. Namun, keadaan paling asas pada kesan PFC adalah daripada ramalan tak teraju-rapi yang disebabkan oleh formula ringkas dan anggapan dinamik input yang sama bagi masa depan. Walau kekangan ini dapat diatasi, namun prestasi akan berubah secara konservatif disebabkan oleh isu ini. Objektif utama kajian ini adalah bagi membaiki kekangan prestasi kawalan PFC dengan modifikasi minimum formula yang ada. Secara spesifik, pendekatan nobel kawalan PFC dicadangkan berdasarkan ramalan lingkaran-tertutup. Selain anggapan input tetap seperti yang dilakukan pada ramalan lingkaran-terbuka yang konservatif, dinamik input yang dibuat pada lingkaran-tertutup telah digunakan bagi mengesan kekangan masa depan yang bertentangan. Tambahan, gangguan yang bakal berlaku pada masa depan telah diperkenalkan ke dalam struktur ramalan sebagai tambahan darjah pada kebebasan bagi mengatasi kekangan. Dua dapatan simulasi kajian menyetujui pendekatan yang dicadangkan dan menyebabkan sangat kurang kekangan pengendalian pada sistem konservatif, oleh itu kawalan yang lebih bagus pada prestasi berbanding pada PFC nominal. Selain itu, pendekatan nobel ini juga menghilangkan kesukaran pelarasan yang dikenali ramai dan ramalan isu tidak konsisten yang terdapat pada PFC konvensional apabila mengendali kekangan.