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Integral Action (integral + action)
Selected AbstractsImproved PI controller with delayed or filtered integral modeAICHE JOURNAL, Issue 12 2002Jietae Lee Integral action is almost always included in process control systems to eliminate steady-state offset without uncertain process gain. The open-loop pole, however, at the origin of the integral term causes some problems such as integral windup. Various methods to solve these problems were studied. For better control performance and robustness, a filter was added to the integral term, which decouples the effective frequency ranges between the integral and proportional terms without degradation of the integral action. It produces a phase lead in a certain frequency range without having a derivative term, enhancing the control performances and stability robustness. Based on the internal model control method or the direct synthesis method, tuning rules for the proposed controller are given. [source] Dynamic characteristics of a PEM fuel cell system for individual housesINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 15 2006S. ObaraArticle first published online: 1 AUG 200 Abstract The method of determination of the control variables for a system controller, which controls the electric power output of a solid-polymer-membrane (PEM) fuel cell system during electric power load fluctuations, was considered. The operation was clarified for the response characteristics of electric power generation for setting the control variables of proportional action and integral action considered to be the optimal for the system controller. The power load pattern of an individual house consists of loads usually moved up and down rapidly for a short time. Until now, there have been no examples showing the characteristics of the power generation efficiency of a system that follows a load pattern that moves up and down rapidly. Therefore, this paper investigates the relation of the control variables and power generation efficiency when adding change that simulates the load of a house to PEM fuel cell cogeneration. As a result, it was shown that an operation, minimally influenced by load fluctuations, can be performed by changing the control variables using the value of the electric power load of a system. Copyright © 2006 John Wiley & Sons, Ltd. [source] Discrete output feedback sliding-mode control with integral actionINTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 1 2006Nai One Lai Abstract This paper presents a novel approach to the problem of discrete time output feedback sliding-mode control design. The method described applies to uncertain systems (with matched uncertainties) which are not necessarily minimum phase or relative degree one. A new sliding surface is proposed, which is associated with the equivalent control of the output feedback sliding-mode controller. Design freedom is available to select the sliding surface parameters to produce an appropriate reduced-order sliding motion. In order for this to be achieved, a static output feedback condition associated with a certain reduced-order system obtained from the original plant must be solvable. The practicality of the results are demonstrated through the implementation of the controller on a small DC motor test rig. Copyright © 2005 John Wiley & Sons, Ltd. [source] Improved PI controller with delayed or filtered integral modeAICHE JOURNAL, Issue 12 2002Jietae Lee Integral action is almost always included in process control systems to eliminate steady-state offset without uncertain process gain. The open-loop pole, however, at the origin of the integral term causes some problems such as integral windup. Various methods to solve these problems were studied. For better control performance and robustness, a filter was added to the integral term, which decouples the effective frequency ranges between the integral and proportional terms without degradation of the integral action. It produces a phase lead in a certain frequency range without having a derivative term, enhancing the control performances and stability robustness. Based on the internal model control method or the direct synthesis method, tuning rules for the proposed controller are given. [source] Generalized sampled-data hold functions for robust multivariable tracking and disturbance rejectionOPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 2 2001Herbert Werner Abstract A new design procedure for a multivariable sampled-data output feedback controller with generalized hold function is proposed. The controller can be designed for different operating points simultaneously. The design of the hold function is carried out in two steps: first the closed-loop discrete-time behaviour is determined by choosing a suitable output injection gain; integral action is incorporated to guarantee zero steady-state error. In a second step this discrete-time behaviour is approximately realized by output feedback with generalized hold. Minimization of a quadratic performance index simultaneously for all operating points yields hold functions with good intersample behaviour. A practical design example and experimental results illustrate the proposed method. Copyright © 2001 John Wiley & Sons, Ltd. [source] Adaptive backstepping integral control of a small-scale helicopter for airdrop missions,ASIAN JOURNAL OF CONTROL, Issue 4 2010Chi-Tai Lee Abstract This paper presents an adaptive Lyapunov-based controller with integral action for small-scale helicopters carrying out airdrop missions. The proposed controller is designed via adaptive backstepping. Unlike the approximate modeling approaches, where the coupling effect of the helicopter is neglected, the proposed method is developed according to a complete dynamic model such that the closed-loop helicopter system is guaranteed to be globally ultimately bounded. Two numerical simulations with airdrops are conducted to exemplify the merits of the proposed controller. Through simulation results, the proposed control method is shown to outperform the well-known controller in Mahony and Hamel, Int. J. Robust Nonlinear Control, Vol. 14, No. (12), pp. 1035,1059 (2004). Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] Optimal grade transition control for liquid-propylene polymerization reactor,ASIAN JOURNAL OF CONTROL, Issue 3 2010Mohammad Al-haj Ali Abstract A nonlinear control system integrating an off-line optimizer and a nonlinear model-based controller is developed to perform optimal grade transition operations in a continuous pilot plant reactor. A simple black-box model is developed and used to determine optimal trajectories of inputs and outputs for a series of three polypropylene grades. The simplified model is also used to develop a nonlinear controller. This controller is similar to generic model control; however, the integral action is omitted and an on-line updating scheme is incorporated to update pre-specified model parameters using delayed process measurements. The time optimal inputs, which are calculated by the off-line optimizer, are introduced to the plant in a feedforward manner. At the same time, the deviations from the optimal output are corrected using the feedback nonlinear controller. The simulations on a complex mechanistic model of the process reveal that the nonlinear control scheme performs well for both set point tracking and disturbance rejection. This paper integrates well-known methodologies, such as the generic-model control algorithm, parameter update schemes, and off-line optimization, together to develop an applicable and robust control technique for continuous polymerization reactors. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source] | ||||||||||