http://control.disp.uniroma2.it/galeani/CO/materiale/automatica2000.pdf

Survey Constrained model predictive control: Stability and optimality

Linear Dynamical Systems.- Semigroups, Generators, and Resolvents.- Perturbation and Approximation of Semigroups.- Spectral Theory for Semigroups and Generators.- Asymptotics of Semigroups.- Semigroups Everywhere.- A Brief History of the Exponential Function.

https://www.springer.com/productFlyer_978-0-387-98463-6.pdf?SGWID=0-0-1297-1590487-0

One-Parameter Semigroups for Linear Evolution Equations

The description of coherent features of fluid flow is essential to our understanding of fluid-dynamical and transport processes. A method is introduced that is able to extract dynamic information from flow fields that are either generated by a (direct) numerical simulation or visualized/measured in a physical experiment. The extracted dynamic modes, which can be interpreted as a generalization of global stability modes, can be used to describe the underlying physical mechanisms captured in the data sequence or to project large-scale problems onto a dynamical system of significantly fewer degrees of freedom. The concentration on subdomains of the flow field where relevant dynamics is expected allows the dissection of a complex flow into regions of localized instability phenomena and further illustrates the flexibility of the method, as does the description of the dynamics within a spatial framework. Demonstrations of the method are presented consisting of a plane channel flow, flow over a two-dimensional cavity, wake flow behind a flexible membrane and a jet passing between two cylinders.

https://hal-polytechnique.archives-ouvertes.fr/hal-01020654/document

Dynamic mode decomposition of numerical and experimental data

1. Introduction. 2. Linear Algebra. 3. Linear Systems. 4. H2 and Ha Spaces. 5. Internal Stability. 6. Performance Specifications and Limitations. 7. Balanced Model Reduction. 8. Uncertainty and Robustness. 9. Linear Fractional Transformation. 10. m and m- Synthesis. 11. Controller Parameterization. 12. Algebraic Riccati Equations. 13. H2 Optimal Control. 14. Ha Control. 15. Controller Reduction. 16. Ha Loop Shaping. 17. Gap Metric and ...u- Gap Metric. 18. Miscellaneous Topics. Bibliography. Index.

/pdf/essentials-of-robust-control-3kaks6yk3h.pdf

Essentials of Robust Control

Time-delay systems: an overview of some recent advances and open problems

The paper addresses torque ripple reduction in current-fed switched reluctance motors (SRMs). Ripple-free torque production in SRMs requires an accurate model that is often too complex for practical implementation. The algorithm proposed here combines the use of a simplified model with adaptation. Explicitly, it includes dynamic estimation of low harmonics of the combined unknown load torque and the ripple in the produced torque (due to model simplification), and adds appropriate terms to the commanded current to cancel these harmonics. The control is based only on the position signal and the speed related information is obtained by an observer. Simulations suggest that our method is indeed effective for constant speed reference commands. Finally, experimental results are included to demonstrate that the algorithm performs well in reducing the torque ripple.

http://ieeexplore.ieee.org/iel5/6364/17023/00785605.pdf

Observer-based adaptive torque-ripple minimization in switched reluctance machines using backstepping

This paper concerns systematic, practical and robust SRM control strategies that achieve very low torque and speed ripple and use the simple position feedback structure. Issues of practical concern include the minimization of voltage input slew rate. Robustness aspects include the accommodation of model inaccuracy and the attenuation of disturbances effects. These control design properties complement and enable successful utilization of the structural advantages of SRM drives. The paper also addresses questions of stability and comparisons with existing position control strategies and feedback linearization based design. >

A family of robust control strategies for switched reluctance motors

We report on an investigation into using a Level Sets based method to reconstruct activation wavefronts at each time instant from measured potentials on the body surface. The potential map on the epicardium is approximated by a two level image and the inverse problem is solved by evolving a boundary, starting from an initial region, such that a filtered residual error is minimized. The advantage of this method over standard activation-based solutions is that no isotropy assumptions are required. We discuss modifications of the Level Sets method used to improve accuracy, and show the promise of this method via simulation results using recorded canine epicardial data.

A method to reconstruct activation wavefronts without isotropy assumptions using a level sets approach

The nonlinearity and high dimension of computational fluid dynamics (CFD) models (O(104) at the low end) reflect fluid dynamics? intrinsic complexity. It is a formidable challenge, setting fluid flow control apart from conventional applications. Its implications include restrictions on model based control design, reliable state estimation, and thus, on feedback implementation. Seeking low order, design accessible models, the issue of an ample dynamic envelope, covering targeted free and actuated transients, is in the essence. We review some enablers for very low order, Galerkin models (GMs). Those include the combination of empirical proper orthogonal decomposition (POD) and physics based modes, estimation of turbulence and pressure effects, actuation models, interpolated models that cover an enhanced dynamic range, and auxiliary, phasor models, focused on sensor readings. The dynamic manifold of model validity must be respected for a meaningful use of the model, but can also be exploited, such as by a restriction to slow drift in the system?s periodic behavior, enabling the use of simplifying dynamic phasor models. Finally, we shall highlight some intrinsic performance limitations in GM based feedback flow control.

Gilead Tadmor

Papers

Observer-based adaptive torque-ripple minimization in switched reluctance machines using backstepping

A family of robust control strategies for switched reluctance motors

A method to reconstruct activation wavefronts without isotropy assumptions using a level sets approach

Control Oriented Models & Feedback Design in Fluid Flow Systems: A Review

Erratum to the article “A Finite-Time Thermodynamics of Unsteady Fluid Flows”