Robust controller design for uncertain systems with variable time delay

García-Sanz, Mario; Guillén, J.C.; Ibarrola, Julio

doi:10.1016/s0967-0661(01)00040-5

Cited by 27 publications

(10 citation statements)

References 15 publications

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“…Caused by the time required to transport mass, energy or information, processing time or by the accumulation of time lags in a number of simple dynamic systems connected in series, dead times, or time delays severely affect the performance of the feedback control loops, producing a decrease in system phase and also giving rise to a non-rational transfer function of the system, making them more difficult to analyse and control [20]. Diverse examples of stochastic time delays in practical engineering applications can be found in the control of recycling stream processes [29], pasteurization processes [30], fluid systems [31], [32] and in network congestion control systems etc [33]. As for FOPDT process, stochastic time delay may obey some probabilistic distribution within some limited region Ω [34] like normal distribution θ ∼ N (μ, σ 2 ).…”

Section: B Stochastic Parameter Uncertainty In Time Delaymentioning

confidence: 99%

IMC-PID tuning method for stable FOPDT processes with stochastic time delay

Zhang

Huang

2014

Proceedings of 2014 IEEE Chinese Guidance, Navigation and Control Conference

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On the basis of IMC framework, this paper addresses PID tuning problem for optimal IAE performance of FOPDT process with stochastic time delay. It should be noted that the traditional deterministic tuning methods can not deal with such problem since they require the exact knowledge or effective estimation of process parameters. From probabilistic point of view, the key idea of the proposed tuning method is to seek and minimize the mean value of IAE in the sense of probability. Meanwhile, the PID tuning rule of the proposed method is derived by means of Maclaurin expansion and the firstorder Taylor approximation that is popular in IMC-PID tuning techniques. In the presence of stochastic time delay in FOPDT process, it shows that the IAE performance of the resulting closed-loop system with the proposed PID tuning is improved in comparison with that of the traditional tuning methods for optimal IAE like

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Section: B Stochastic Parameter Uncertainty In Time Delaymentioning

confidence: 99%

IMC-PID tuning method for stable FOPDT processes with stochastic time delay

Zhang

Huang

2014

Proceedings of 2014 IEEE Chinese Guidance, Navigation and Control Conference

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“…However it is Proceedings of the 46th IEEE Conference on Decision and Control New Orleans, LA, USA, Dec. [12][13][14]2007 FrA16.6 well-known that when significant uncertainty exists either within the time-delay or the rational part of the system model, SPC may be very sensitive to the mismatch between the inner-loop model and actual system model [6]. In [12], an alternative robust PC design has been proposed using linear matrix inequality (LMI) concept and and H ∞ theory.…”

Section:  mentioning

confidence: 99%

Robust power control for CDMA cellular communication networks using quantitative feedback theory

Alavi

Hayes

2007

2007 46th IEEE Conference on Decision and Control

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Abstract-In this work, a new transmission power control algorithm based on the use of Quantitative Feedback Theory (QFT) is proposed for CDMA wireless cellular networks. The QFT based loop-shaping framework that is considered fully compensates the effect of link round-trip time delay within the network. The design supports predefined levels of performance robustness in the presence of channel uncertainty and signal interference. A novel stability boundary is introduced based on the use of the Jury Array that informs the necessary trade-off between disturbance attenuation and system stability. Extensive simulation results are provided that illustrate the effectiveness of the proposed methodology.Index Terms-Power control, Wireless cellular network, Quantitative feedback theory (QFT). I. IWith the rapid growth of wireless networks, there is an increasing demand for Quality of Service (QoS). In codedivision-multiple-access (CDMA) system many users share the same channel. In such a case, the power receiver from users close to the base station is much higher than that received from users further away. Therefore, a user close to the base will constantly create a lot of interference for users far from the base station, making their reception impossible. This near-far effect can be solved by applying an appropriate power control (PC) algorithms so that all users are received by the base station with the same average power. As wireless radio channels are typically affected by exogenous, uncertain factors that have an adverse impact on system performance such as path loss, shadowing and fading effects as well as noise and time delay; PC is clearly a challenging objective.In this work, a new Active Power Control (APC) algorithm is presented based on quantitative feedback theory. The basis for the work relies on the following assumptions that: (i) it is feasible to adjust the transmission power in an appropriate fashion in each base-mobile, (ii) the received signal quality at a receiver can be reliably measured using a signal-tointerference-noise ratio (SINR) type metric. It is also noted that the focus of the is on uplink system (communication from mobile users to the base station).Consider a wireless cellular system consisting of N user and M fixed base stations. The SINR for i-th user in the desired cell is given by, [17]: where g i j represents the channel gain between i-th base staion and j-th subscriber. p j also denotes the power that j−th user consumes for packet transmission. σ 2 i is the power of the white noise at the base station i. I i represents both inter and intracell interferences. SINR represented in (1), contains sufficient information on channel gain and interference so that an APC algorithm based on SINR feedback control can address the existing issues.In practice, an APC algorithm should have the properties of simplicity, the ability to adjust the power levels of each transmitted signal using only local measurements, in a reasonable time, and to maintain a desired signal-to-interference rati...

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“…The Smith predictor is considered an effective method to remove the time delay effect in many applications, where valid linear model are available [4,9,10] and at the time the method was proposed, powerful non-linear modelling, computing and control techniques were not sufficiently matured. The ability to map non-linearities using neural networks [11,121 and to integrate highspeed data processing make it feasible to consider a neural network predictor in the control loop to improve positioning accuracy and response speed of the pneumatic servo-actuator in this study.…”

Section: Normenclature C Output Of a Neuron D(z)mentioning

confidence: 99%

Position Control of a Pneumatic Servoactuator With Time Delay Using a Neural Network Predictor

Xue

Watton

2002

Proceedings of the JFPS International Symposium on Fluid Power

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ABASTRACTConsideration is given to data-based dynamic modelling and positioning of a pneumatic servo-actuator with time delay due to friction and air compressibility. A Smith predictor-type control scheme is considered to improve the control behaviour. System non-linearity is verified by the inability of linear modelling to provide satisfactory prediction. Data based dynamic modelling is undertaken using the group method of data handling(GMDH) neural network, a feedforward type neural network, and the techniques show potential for prediction of non-linear behaviour. Hence the time delay effect to the closed-loop control can be removed by incorporating the trained nonlinear model as a predictor in the feedback path. Conventional feedback control with/without the predictor are compared, and it is shown that the time delay system stability is significantly improved by using the non-linear predictor. The effect of time delay is most significant at small stroke changes of fast response demand and experiments were undertaken around the mid-stroke, which is less damped than any other position.

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Robust controller design for uncertain systems with variable time delay

Cited by 27 publications

References 15 publications

IMC-PID tuning method for stable FOPDT processes with stochastic time delay

IMC-PID tuning method for stable FOPDT processes with stochastic time delay

Robust power control for CDMA cellular communication networks using quantitative feedback theory

Position Control of a Pneumatic Servoactuator With Time Delay Using a Neural Network Predictor

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