This paper proposes a new approach to disturbance estimation based on a curvature model to improve the disturbance rejection performance of a servo system. The main feature is that the stability of the control system is guaranteed when the disturbance estimation is incorporated directly into the designed control law. Simulation results show that disturbances are rejected efficiently when this a...

This paper studies the problem of disturbance attenuation with internal stability via output feedback for a family of nonlinear systems. Using a feedback domination design which substantially differs from the separation principle, we explicitly construct a dynamic output compensator attenuating the disturbance’s effect on the output to an arbitrary degree of accuracy in the L2-gain sense, and a...

A generalized linear stability analysis is applied to the case of a thin liquid film propelled to spread by a continuous supply of surfactant. The time-dependent base states for the film thickness and surfactant concentration give rise to a nonautonomous system describing disturbance propagation. As a first approximation, the nonautonomous operator is treated as time independent, thereby reduci...

Most of the practical systems are having uncertainty which makes it difficult to maintain stability and better performance. In this paper a robust controller design, based on the quantitative feedback theory (QFT) is proposed for a nonlinear process like Spherical tank system and bioreactor. The QFT controller is designed to ensure the robust stability and performance (input and output disturba...

Analysing the consequences of the decrease in biodiversity for ecosystem functioning and stability has been a major concern in ecology. However, the impact of decline in soil microbial diversity on ecosystem sustainability remains largely unknown. This has been assessed for decomposition, which is insured by a large proportion of the soil microbial community, but not for more specialized and le...

Embedded Model Control (EMC) methodology is applied to web-winding control problems. These require time-varying Embedded Model and adaptive control law, because of a variable winder radius; disturbance estimation and rejection, because of friction and variable web speed and acceleration; sensorless reel radius estimation; and robust stability and performance in the presence of web and gear vibr...

The disturbance accommodating control theory provides a method for designing feedback controllers which automatically detect and minimize the effect of waveform-structured disturbances. This paper presents a disturbance accommodating controller which utilizes a Kalman estimator to determine the necessary corrections to the nominal control input and thus minimizes the adverse effects of model un...