Conventional Dynamic Matrix Control Research Articles

Robust stability conditions for DMC controller with uncertain time delay

For Networked Control Systems (NCSs), the conventional Dynamic Matrix Control (DMC) may not applicable due to the unknown transmission delay. The uncertain time delay was usually converted to constant time delay by using registers. This paper addresses the stability problem for single-input-single-output (SISO) linear NCSs with uncertain time delay via DMC controller. A novel DMC controller which is effective for such NCSs has been proposed. Applying Jury’s dominant coefficient lemma, the sufficient stability and stabilization conditions are presented. Finally, numerical examples are given to demonstrate the theoretical results.

An Adaptive Dynamic Matrix Control With Fuzzy-Interpolated Step-Response Model for a Drum-Type Boiler-Turbine System

In this paper, dynamic matrix control (DMC) is made adaptive for a boiler-turbine system by using online interpolated step-response model (SRM) with fuzzy inference. A plant is described as an SRM in a conventional DMC. However, a nonlinear boiler-turbine system cannot be effectively modeled as a single SRM. In this paper, the plant is modeled with nine SRMs at various operating points, and then they are interpolated with fuzzy inference rules. The interpolation is performed at every sampling step online in order to find the best SRM for an arbitrary operating point. Therefore, the proposed adaptive DMC can achieve a bumpless control for nonlinear systems. Simulation results show satisfactory result with a wide range operation of a boiler-turbine system.

Robust stability conditions for remote SISO DMC controller in networked control systems

A two level hierarchy is employed in the design of networked control systems (NCSs) with bounded random transmission delay. At the lower level a local controller is designed to stabilize the plant. At the higher level a remote controller with the dynamic matrix control (DMC) algorithm is implemented to regulate the desirable set-point for the local controller. The conventional DMC algorithm is not applicable due to the unknown transmission delay in NCSs. To meet the requirements of a networked environment, a new remote DMC controller is proposed in this study. Two methods, maximum delayed output feedback and multi-rate sampling, are used to cope with the delayed feedback sensory data. Under the assumption that the closed-loop local system is described by one FIR model of an FIR model family, the robust stability problem of the remote DMC controller is investigated. Applying Jury’s dominant coefficient lemma and some stability results of switching discrete-time systems with multiple delays; several stability criteria are obtained in the form of simple inequalities. Finally, some numerical simulations are given to demonstrate the theoretical results.

ADAPTIVE DYNAMIC MATRIX CONTROL FOR NETWORK-BASED CONTROL SYSTEMS WITH RANDOM DELAYS

Random transfer delays in network-based control systems (NCSs) degrade the control performance and can even destabilize the control system. To address this problem, the adaptive dynamic matrix control (DMC) algorithm is proposed. The control algorithm is derived by applying the philosophy behind DMC to a discrete time-delay model. A method to estimate the network-induced delays is also presented to facilitate implementation of the control algorithm. Finally, an NCS platform based on the TrueTime simulator is constructed. With it, the adaptive DMC algorithm is compared with the conventional DMC algorithm under different network conditions. Simulation results show that the proposed adaptive DMC algorithm can respond to various network conditions adaptively and achieve better control performance for NCSs with random transfer delays.

계단 응답 모델의 보간을 이용한 화력발전 보일러-터빈 시스템의 동역학 행렬제어(DMC)에 관한 연구

동역학 행렬제어(Dynamic Matrix Control) 기법은 각종 산업 현장에서 가장 활발하게 적용되고 있는 고급 제어 기법으로, 최근에는 공정제어의 표준 기법으로 인식되고 있다. 동역학 행렬제어에서는 대상 플랜트의 거동을 묘사하기 위하여 계단 응답 모델(Step Response Model)을 이용한다. 한편 화력발전의 보일러-터빈시스템은 심한 비선형성과 넓은 운전영역으로 인하여 기존의 선형제어기법으로 제어하기에는 그 성능의 한계가 있게 된다. 본 논문에서는 미리 선정된 동작점에서 계단 응답 모델을 개발한 후, 이를 통한 실시간 보간(Interpolation)을 통하여 계단응답 모델을 실시간으로 개선하는 동역학 행렬제어 기법을 제시한다. 제시된 제어 기법은 화력발전의 보일러-터빈 시스템에 적용하여 만족할 만한 제어 성능을 확인하였다.

An Adaptive Dynamic Matrix Control of a Boiler-Turbine System

This paper proposes an adaptive Dynamic Matrix Control (DMC) and its application to boilerturbine system. In a conventional DMC, object system is described as a Step Response Model (SRM). However, a nonlinear system is not effectively described as a single SRM. In this paper, nine SRMs at various operating points are prepared. On-line interpolation is performed at every sampling step to find the suitable SRM. Therefore, the proposed adaptive DMC can consider the nonlinearity of boiler-turbine system. The simulation results show satisfactory results with a wide range operation of the boiler-turbine system.

Model predictive control of a nonlinear unstable process

In this work, conventional (fixed model) dynamic matrix control (DMC), and adaptive (variable model) DMC which combines on-line parameter estimation via a recursive least squares algorithm and control are carried out on a nonlinear, unstable process. The controlled process has multiple steady states one of which is unstable. The control around the unstable point using DMC is done in a cascade arrangement. In the inner loop the unstable process is stabilized with an analog proportional only controller. This stabilized process is then controlled by the outer loop DMC. With this configuration stable control is achieved with the conventional DMC; whereas the stability and the performance of the system with the adaptive DMC is found to be dependent on the controller parameters.