CORDIS - EU research results

Robust control of infinite dimensional systems

Final Activity Report Summary - ROCOIDS (Robust Control of Infinite Dimensional Systems)

Feedback control is an essential part of almost all engineering systems. Its main purpose is to reduce the effect of the uncertainty in the form of disturbance signals and modelling errors. This project dealt with robust control of a class of physical processes where the dynamical model was an infinite dimensional system. These types of mathematical models appeared when there was time delay in the process or in cases where the system was spatially distributed.

There were three major lines of work within the framework of the ROCOIDS project:
1. the development of new robust controller design techniques;
2. applications on time delay systems, in particular the design of congestion control schemes in computer communication networks, e.g. data flow controllers, and the development of active queue management algorithms;
3. the design of aerodynamic flow controllers, with the specific problem of interest being the suppression of cavity flow oscillations in aircrafts and other aerodynamics' applications.

The newly developed robust controllers displayed improvements in comparison to existing methods. For example, in the active queue management of Transmission control protocol (TCP) flows, tracking of a target queue led to reduction in delay jitter as compared to standard techniques, such as random early detection and proportional plus integral control scheme which were proposed by others. The results on active queue management were demonstrated using ns-2 simulations. Collaborations with a group of researchers at the Ohio State University (OSU) led to novel controllers for cavity flow suppressions, which were successfully tested on an experimental facility at OSU.