Adaptive observer for systems with pure time delay

1979 ◽  
Vol 15 (11) ◽  
pp. 329 ◽  
Author(s):  
Zenta Iwai ◽  
Yoshinori Kawasaki
Keyword(s):  
Time Delay ◽  
Adaptive Observer ◽  
Pure Time Delay

scholarly journals Decoupling Adaptive Smith Prediction Model of Flatness Closed-Loop Control and Its Application

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 895
Author(s):  
Mingming Song ◽  
Hongmin Liu ◽  
Yanghuan Xu ◽  
Dongcheng Wang ◽  
Yangyang Huang
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Time Delay ◽  
Control Method ◽  
Delay System ◽  
Control Performance ◽  
Time Delay System ◽  
Single Loop ◽  
Flatness Control ◽  
Pure Time Delay

Flatness control system is characterized by multi-parameters, strong coupling, pure time delay, which complicate the establishment of an accurate mathematical model. Therefore, a control scheme that combines dynamic decoupling, PI (Proportion and Integral) control and adaptive Smith predictive compensation is proposed. To this end, a dynamic matrix is used to decouple the control system. A multivariable coupled pure time-delay system is transformed into several independent generalized single-loop pure time-delay systems. Then, a PI-adaptive Smith predictive controller is constructed for the decoupled generalized single-loop pure time-delay system. Simulations show that the scheme has a simple and feasible structure, and good control performance. When the mathematical model of the control system is inaccurate, the control performance of adaptive Smith control method is evidently better than that of the ordinary Smith control method. The model is successfully applied to the cold rolling production site through LabVIEW, and the control accuracy is within 5I. This study reveals a new solution to the problem of coupled pure time-delay in flatness control system.

scholarly journals Improved unit hydrograph characterisation of the daily flow regime (including low flows) for the River Teifi, Wales: towards better rainfall-streamflow models for regionalisation

2002 ◽  
Vol 6 (5) ◽  
pp. 899-911 ◽  
Author(s):  
I.G. Littlewood
Keyword(s):  
Time Delay ◽  
Model Fit ◽  
Temperature Modulation ◽  
Rainfall Runoff ◽  
Unit Hydrograph ◽  
New Model ◽  
Low Flows ◽  
Starting Point ◽  
Improved Model ◽  
Pure Time Delay

Abstract. An established rainfall-streamflow modelling methodology employing a six-parameter unit hydrograph-based rainfall-runoff model structure is developed further to give an improved model-fit to daily flows for the River Teifi at Glan Teifi. It is shown that a previous model of this type for the Teifi, which (a) accounted for 85% of the variance in observed streamflow, (b) incorporated a pure time delay of one day and (c) was calibrated using a trade-off between two model-fit statistics (as recommended in the original methodology), systematically over-estimates low flows. Using that model as a starting point the combined application of a non-integer pure time delay and further adjustment of a temperature modulation parameter in the loss module, using the flow duration curve as an additional model-fit criterion, gives a much improved model-fit to low flows, while leaving the already good model-fit to higher flows essentially unchanged. The further adjustment of the temperature modulation loss module parameter in this way is much more effective at improving model-fit to low flows than the introduction of the non-integer pure time delay. The new model for the Teifi accounts for 88% of the variance in observed streamflow and performs well over the 5 percentile to 95 percentile range of flows. Issues concerning the utility and efficacy of the new model selection procedure are discussed in the context of hydrological studies, including regionalisation. Keywords: unit hydrographs, rainfall-runoff modelling, low flows, regionalisation.

More on the simulation of a pure time delay

SIMULATION ◽  
1974 ◽  
Vol 23 (4) ◽  
pp. 126-127 ◽  
Author(s):  
M.G. Reggiani ◽  
F.E. Marchetti
Keyword(s):  
Time Delay ◽  
Pure Time Delay

Control of pure time delay processes

1975 ◽  
Vol 30 (2) ◽  
pp. 207-215 ◽  
Author(s):  
C. Chandra Prasad ◽  
P.R. Krishnaswamy
Keyword(s):  
Time Delay ◽  
Pure Time Delay

Pure Time Delay Analysis for Decentralized Networked Control Systems

2014 ◽  
Author(s):  
Ahmad F. Taha ◽  
Ahmed Elmahdi ◽  
Jitesh H. Panchal ◽  
Dengfeng Sun
Keyword(s):  
Control System ◽  
Time Delay ◽  
Control Systems ◽  
Decentralized Control ◽  
Control Method ◽  
Networked Control System ◽  
Networked Control ◽  
Space Representation ◽  
Global Dynamics ◽  
Pure Time Delay

The network disturbance effect can be considered as either a perturbation or as a pure time delay for the exchanged signals. The network-induced time delay is one of the main challenges when a network is inserted in the feedback loops of a control system. In this paper, our objective is to improve the behavior of a Networked Control System (NCS) by analyzing the time-delay given that the decentralized control design method is adopted. First, we review an observer-based control method for decentralized control systems. Second, we establish a map between the decentralized non-networked system, and the typical NCS state-space representation. The main idea the mapping is to put the Decentralized Networked Control System (DNCS) in a general form and then map the resulting system to the typical NCS form. Third, we derive the global dynamics of the DNCS. Fourth, an upper bound for the time-delay is derived that guarantees the stability of LTI DNCSs. Finally, we present a numerical example that illustrates the applicability of the derived bound.

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