The objective of this work is to formulate and demonstrate the methodology of multi-models for improving the performance of existing advanced control strategies. Multiple models are used to capture the nonlinear process dynamics relating to gain and time constant variations. The multi-model strategy was implemented on several controllers such as Smith-Predictor using PI (Proportional-Integral) ...

This paper deals with a novel method of continuous-time model-predictive control for nonlinear time-delayed systems. The problems relating to time delays are solved by incorporating the Smith-predictor scheme in a control-law derivation. A nonlinear-mapping approximation, employing either continuous piece-wise linear functions or a fuzzy system, is also an integral part of the control scheme, a...

Congestion control is a fundamental building block in packet switching networks such as the Internet due to the fact that communication resources are shared. It has been shown that the plant dynamics is essentially made of an integrator plus time delay and that a proportional controller plus a Smith predictor defines a simple and effective controller. It has been also shown that the today runni...

When a mobile robot uses vision for self-localization and obstacle avoidance, the results of image processing become available after a variable computational delay. If the robot keeps moving during image processing, results become available after the robot has left the position where the image was taken. This is the problem of control in presence of intermittent delayed feedback. This paper pro...

In this paper, a novel control scheme is proposed on the basis of the well-known Smith predictor for the control of integrating processes with long time delay. It can provide one and half degree-of-freedom for the closed loop system tuning. Systematic design procedure is developed by employing optimal control theory, and simple and efficient tuning rules are derived analytically. It is shown th...

Finding good controller settings that satisfy complex design criteria is not trivial. This is also the case for the simple three parameter pid controller. One strategy is to formulate the design problem into an optimization problem. However, when using gradient-based optimization, the algorithm often fails to converge to the optimal solution. In many cases this is a result of inaccuracies in th...

The main aim of the paper is to present a Matlab program for control of time-delay systems using three various modifications of Smith predictor. The software implementation includes the modification for unstable and integrating processes, PI-PD modification for systems with long dead time, and modification applying control design by Coefficient Diagram Method (CDM). The freely downloadable prog...

This paper examines the inverse control problem of nonlinear systems with stable dynamics using a fuzzy modeling approach. Indeed, based on the ability of fuzzy systems to approximate any nonlinear mapping, the nonlinear system is represented by a Takagi-Sugeno (TS) fuzzy system, which is then inverted for designing a fuzzy controller. As an application of the proposed inverse control methodolo...

with Communication Delays ASHU AHUJA, S. K. AGGARWAL 2 Electrical Engineering Department, Maharishi Markandeshwar University, Mullana, INDIA [email protected], [email protected] Abstract:The presence of communication delay in modern load frequency control (LFC) systems complicates the design and implementation of the controller to achieve robust performance of the system. In th...

A modiÞcation of the Smith Predictor Control schemes is introduced. This modiÞcation consists in a periodical resetting of the initial condition of the predictor. It allows to extend the use of these control laws to unstable linear systems with delay. The continuous and discrete implantation of this scheme is considered. The stability of the scheme is proved and sufficient conditions for robust...