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- Nonlinear control for infinite-dimensional process systems: fault-tolerant distributed application for heat exchangersPublication . Costa, Sérgio; Igreja, José; Mota, J. P.; Lemos, J. M.In this work a robust pointwise min-norm controller is developed as a stabilizing solution for a transport-reaction phenomena process, described by nonlinear partial differential equations. The control solution is further combined with adaptation for robustness to parametric uncertainty. The application of centralized and fault-tolerant distributed control versions is accounted for a countercurrent heat exchanger and documented in a series of simulations.
- On modal decomposition and model uncertainty bounds for linear distributed parameter transport systemsPublication . Igreja, José; Lemos, J. M.Some distributed parameter system can be decomposed into a modal form for dynamic analysis and control design purposes. Once decomposed, high accuracy approximate time solutions and frequency uncertainty bounds can be computed, enabling early lumping in robust controller design. In this paper the focus is on finding realizable modal decompositions via partial fraction expansion for a vast class of infinite-dimensional dynamical systems related to the study of transport phenomena regarding the exchange of mass, energy, and momentum in process systems. A double-pipe heat exchanger in countercurrent is used for validation of the proposed approach.
- Soft flocks for rendezvous and pursuit missions with distributed MPCPublication . Igreja, José; Lemos, J. M.This paper concerns of MPC (Model Predictive Control) solutions for self-organized or soft flock formations of agents while carrying out an assigned mission. A distributed MPC algorithm is proposed to solve the formulated problem. Pursuit missions by agents formations can also be treated with the exact same algorithm. The obtained solution is completely decentralized in terms of pathfinding and mission completion. The coordination is done only by shared information between the agents, without any additional gathering node or other extra features, like a pre-planning or mission control. Collisions avoidance with obstacles and among agents are solved by introducing coupling constraints in the underlying optimization problem. The algorithm follows the protocol of a Stackelberg strategy game with a finite number of plays seeking an equilibrium outcome. Two examples are presented, the first showing a rendezvous mission and a second one where agents pursuit a moving object, illustrating the wide range of applications for the proposed algorithm.
- Analysis and loop-shaping of holomorphic dynamical PDE systemsPublication . Igreja, José; Lemos, J. M.Holomorphic Dynamical systems is a class of infinite dimensional systems with a infinite number of zeros and no poles. Systems in this class are always BIBO stable with an exact finite settling time for the step response, because they are in feedforward mode, without any inherent feedback physical mechanism. In this paper a precise definition of Holomorphic Dynamical systems is given along with a stability result. Time solutions are also discussed and its control is addressed. This kind of systems are often present in PDE modelling of mass and energy transport phenomena for industrial plant units. Examples and one control application are presented, illustrating the approach described.