Aron Pila - Academia.edu (original) (raw)

Papers by Aron Pila

A new method is proposed for the solution of linear matrix inequalities over a finite horizon for... more A new method is proposed for the solution of linear matrix inequalities over a finite horizon for linear discrete time varying systems with or without uncertainties. The method is used to solve a variety of problems beginning with the standard H∞ discrete-time bounded real lemma and extending through to robust H∞ general-filtering and output-feedback control design of uncertain systems. In the latter case we show, that our design compare favorably, with existing results.

A linear parameter varying approach is introduced for the design of a constant state-feedback con... more A linear parameter varying approach is introduced for the design of a constant state-feedback controller that locally stabilizes linear systems with state time-varying delays and saturating actuators and achieves a prescribed performance level for all disturbances with uniformly bounded magnitudes. A polytopic representation is used to describe the saturation behaviour. Delay-dependent sufficient conditions in terms of linear matrix inequalities (LMIs) are obtained for the existence of such a controller. An estimate is made of the domain of attraction for the disturbance-free system. The conditions for the stabilizability and H 1 performance of the system apply the Lyapunov-Krasovskii functional and the recent descriptor approach to the control of time-delay systems, whereas the conditions for finding an ellipsoid that bounds the set of the states (in the Euclidean space) that are reachable from the origin in finite time are obtained via the Razumikhin approach. The resulting conditions are expressed in terms of linear matrix inequalities, with some tuning parameters, and they apply a different Lyapunov function to each of the vertex points that stem from the polytopic description of the saturation in the actuators.

International Journal of Robust and Nonlinear Control, 2003

A linear parameter varying approach is introduced for the design of a constant state‐feedback con... more A linear parameter varying approach is introduced for the design of a constant state‐feedback controller that locally stabilizes linear systems with state time‐varying delays and saturating actuators and achieves a prescribed performance level for all disturbances with uniformly bounded magnitudes. A polytopic representation is used to describe the saturation behaviour. Delay‐dependent sufficient conditions in terms of linear matrix inequalities (LMIs) are obtained for the existence of such a controller. An estimate is made of the domain of attraction for the disturbance‐free system. The conditions for the stabilizability and H∞ performance of the system apply the Lyapunov–Krasovskii functional and the recent descriptor approach to the control of time‐delay systems, whereas the conditions for finding an ellipsoid that bounds the set of the states (in the Euclidean space) that are reachable from the origin in finite time are obtained via the Razumikhin approach. The resulting conditi...

Introduction To Lagrangian Dynamics, 2019

Lagrangian dynamical systems with non-holonomic constraints is the main topic of this chapter. Th... more Lagrangian dynamical systems with non-holonomic constraints is the main topic of this chapter. This category of systems is first transformed into a “standard” d’Alembert–Lagrangian form by means of a set of Lagrangian multipliers applied to the constraints.

Proceedings of 35th IEEE Conference on Decision and Control

The problem of achieving a prescribed bound on the induced /spl Lscr//sub 2/-norm of the operator... more The problem of achieving a prescribed bound on the induced /spl Lscr//sub 2/-norm of the operator relating the exogenous disturbances with the objective signal is considered for linear time-varying systems with delayed measurements and a norm-bounded parameter uncertainty. A robust controller is derived which satisfies the required /spl Hscr//sub /spl infin// level over the whole uncertainty range.

IFAC Proceedings Volumes

Abstract The pulp and Paper industry is snowing increasing interest in a pulping process known as... more Abstract The pulp and Paper industry is snowing increasing interest in a pulping process known as Tnermo-mechanical Pulping - or TMP for snort. In one example of this process wood chips are “refined” to wood pulp directly by mechanical and thermodynamic forces set up between the contra-rotating plates of a so-called TMP Refiner. In the purest form of TMP no chemicals are used to delignify the wood - thus the “yiela” (names of pulp from unit mass of wood) is high, as in other forms of mechanical pulping, however, the chips are usually heated in a pre-steaming or impregnation vessel - often called (incorrectly) a “digester”. Refiner plates are ariven of very large electric motors. A total of 7 1/2 MW of mechanical energy dissipated between 1.5 meter diameter plates space a less than 1mm, is not unusual. The resulting mechanical shear and heating“explode” the chips to fibrous pulp. Two stages of refining (Primary and Seconoary) are generally used. The process brings us difficult but interesting control problems. Material hold-up is low, response times are fast and plate damage easily occurs if chip supply is interrupted or “pulp pad” collapses. Also, the process is noisy and non-linear. Process controls must accomodate all this, yet be robust enough for ease of use. The paper discusses a distributed hierarchical approach to the control of a typical thermo-mechanical pulping (TMP) process. Key process variables are presented and a control philosophy and structure is outlined. Controls for production rate, specific energy and freeness are presented as modular subsystems. Controls are best implemented by microprocessor-based instrumentation together witn a process computer. Process modelling by means of least-squares estimation for one of the key subsystems is described and a control algorithm is derived from the model.

Automatic Control, IEEE …, 1999

VI. CONCLUDING REMARKS We have studied the problem of output feedback tracking control of manipul... more VI. CONCLUDING REMARKS We have studied the problem of output feedback tracking control of manipulators under holonomic constraints. We used a reduced-order model whose particular feature, and advantage in relation to other models available in the literature, is that the ...

Proceedings of the European control conference ( …, 2001

Introduction To Lagrangian Dynamics

6th IFAC Symposium on Robust Control Design, 2009, 2009

AIAA Modeling and Simulation Technologies Conference and Exhibit, 2008