Advanced Control of Processes with Transport Phenomena

The FLOW project aims the development of Advanced Non-Linear and Adaptive Control methodologies for distributed parameter systems with transport phenomena. These methods are to be applied in different case studies such as

1. the control of car density in highway traffic flow;
2. the control of water flow in a water distribution channel system;
3. the control of temperature in large-scale distributed heat-exchangers.

Although these applications can be viewed as quite different in their essence, they share an important common characteristic, as the three of them can be modelled by a hyperbolic partial differential equation (PDE) resulting from the natural transport phenomena. This forms a strong common basis for control. Examples of large-scale heat-exchangers include superheated steam in thermoelectric power plants and distributed collector solar fields. In both cases the dynamics are affected by the flow. For the car density in highways the transport phenomena is direct (with diffusion associated with the dispersion of behaviours between the different vehicles in the stream), the control being made through variable speed limits in certain road segments. The water channel system case study has again mass transportation (water distribution) but the control is performed by changing the flow through the actuation on several floodgates along the channel. Also, for the three cases different disturbance effects are present.

The proposed strategy for controlling these systems consists of two main steps: a) Adequate spatial and/or temporal discretization; b) Application of methods of Adaptive and/or Non Linear control to the resulting system. While classical methods consider grids which are uniform in time and space, this project follows another approach allowing better integration of steps a) and b) and witch reflects in increased control performance. It amounts in practice to a variable change in the time scale and/or a change of the variable to control. The approach to follow assumes an engineering standpoint reflected in the practical examples discussed above that don't deplete the number of other applications of these methods. Besides the aspects of control algorithm structure, two important questions to consider are the study of the stability of the internal dynamics and the robustness with respect to modelling errors, using non-linear methods.

Project duration: 36 months (Mar-05 to Feb-08)

Partners: UNINOVA (Coordination, PT), INESC-ID (PT), Universidade de Évora (PT)

Project coordinator: Rui Neves-Silva - UNINOVA (r n s @ f c t . u n l . p t)