Authors: Levant, Arie

Abstract: Most known high-order sliding mode controllers are homogeneous. Homogeneous sliding modes were recently proved to be robust with respect to the presence of small delays, various switching imperfections, measurement errors and unaccounted-for dynamics of fast stable actuators and sensors. It is proved in the paper that they are also robust with respect to small perturbations, which do not preserve the relative degree of the sliding variable. The corresponding asymptotic sliding-mode accuracy is calculated. General results are obtained on asymptotic accuracy of perturbed homogeneous differential inclusions.

Keywords: Variable Structure Control; Robust Nonlinear Control

Identifier: 10.3182/20090616-3-IL-2002.00029

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: Shtessel, Yuri B.; Edwards, Christopher; Spurgeon, Sarah K.

Abstract: Second order sliding mode control laws with adaptation are designed for the first and second order dynamic systems. The designed controllers do not contain any discontinuity while retaining robustness to bounded disturbances with unknown bounds. Simulation results manifest the efficacy of the proposed algorithms.

Keywords: Variable Structure Control; Parametric Uncertainties

Identifier: 10.3182/20090616-3-IL-2002.00032

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: Luviano-Juárez, Alberto; Cortés-Romero, John Alexander; Sira-Ramirez, Hebertt J.

Abstract: In this article, an output feedback discrete time sigma delta-modulation based sliding mode controller is proposed for the stabilization and trajectory tracking of output voltages in a Buck power converter model. The average dynamic output feedback control scheme is realized by a means of a generalized proportional integral (GPI) controller.

Keywords: Switched Systems; Variable Structure Control

Identifier: 10.3182/20090616-3-IL-2002.00034

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: Orlov, Yury; Meza-Sánchez, Marlen; Aguilar, Luis T.

Abstract: Sliding mode control synthesis is developed for an underactuated mechanical system. A laboratory helicopter prototype is used as a test bed. Both state feedback design and dynamic output feedback design with sliding mode velocity observers, running in parallel, are proposed. Performance and robustness issues of the closed-loop system are illustrated in a numerical study. The work is in progress and the conference presentation is going to be supported by experimental results.

Keywords: Variable Structure Control; Spacecraft Control

Identifier: 10.3182/20090616-3-IL-2002.00031

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: Rusnak, Ilan; Barkana, Itzhak

Abstract: The theory, proofs, use and implementation of robust adaptive control algorithms require the understanding of the concepts of Strictly Positive Real (SPR) and Almost Strictly Positive Real (ASPR) plants. Although these concepts are defined in the existing literature, both in time and frequency domains, their grasp is not straight forward for the practicing control engineer that deals with real-world plants. Here, we attempt to present the interpretation and meaning of these concepts in a more intuitive way for the practicing control engineer. That is, we use the Bode, Nyquist, Nichols and Root-Locus domains that may help the control engineer better grasp their implications. The paper is oriented towards the practitioner and therefore any proof that already appears in the literature is only cited. An important result that is formalized and proved is that any stable system can be made ASPR. An example is also given in order to demonstrate these concepts.

Keywords: Robust Adaptive Control; Robust Stability and Performance

Identifier: 10.3182/20090616-3-IL-2002.00022

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: Margaliot, Michael; Branicky, Michael S.

Abstract: We consider the stability analysis of switched systems under arbitrary switching laws. A powerful approach for addressing this problem is based on studying the "most unstable" switching law (MUSL). If the switched system is stable for the MUSL, it is stable for any switching law. The MUSL can be defined as the solution to a certain optimal control problem. The main analysis tool is then the celebrated maximum principle (MP). This provides an implicit characterization of the MUSL in terms of the adjoint and switching function defined in the MP. In this paper,we consider the optimal control problem defining the MUSL for the particular case of positive linear switched systems. We show that in this case the MP can be strengthened. Specifically, there exist regions in the state-space for which the MUSL is known explicitly.

Keywords: Switched Systems

Identifier: 10.3182/20090616-3-IL-2002.00006

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: Caliskan, Sina Yamac; Ozbay, Hitay

Abstract: In this paper we consider the heat equation with time delayed feedback. Recently, stability analysis of this system, with possibly time-varying delay, is done by Fridman and Orlov (2007, 2009); and a sufficient condition is obtained for stability in terms of a linear matrix inequality. Here we consider the same system, but with constant delay, and perform the stability analysis in the frequency domain. A necessary and sufficient condition is obtained in terms of the system parameters. The result is illustrated with numerical examples.

Keywords: Robust Control for Distributed Parameter Systems; Frequency domain methods; Robust Stability and Performance

Identifier: 10.3182/20090616-3-IL-2002.00038

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: Husek, Petr

Abstract: The paper deals with the problem of determining stability margin of linear continuous-time systems with parametric uncertainty. The coefficients of characteristic polynomial with linear affine dependency on system parameters are considered. The system parameters are supposed to vary in intervals with the endpoints parameterized by arbitrary functions that e.g. allows to consider cases where the nominal point does not lie in the middle of admissible intervals. An elegant solution, graphical in nature, based on generalization of Tsypkin-Polyak plot is presented.

Keywords: Parametric Uncertainties; Robust Stability and Performance; Frequency domain methods

Identifier: 10.3182/20090616-3-IL-2002.00009

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: Yaesh, Isaac; Shaked, Uri

Abstract: A non-smooth optimization approach for designing a constant output feedback controller for a linear time-invariant system is considered. The design requirements combine both Hinfinity performance requirements together with regional pole constraints. The pole constraints are embedded in the design criterion using a transformation on the system model which modifies the Hinfinity-norm of the closed-loop system via a barrier function that is related to the closed-loop poles damping. The method is applied to a flight control example.

Keywords: H-inf and l-1 Optimal Control and Estimation; Parametric Uncertainties; Robust Stability and Performance

Identifier: 10.3182/20090616-3-IL-2002.00026

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: None

Abstract:

Keywords:

Identifier: 10.3182/20090616-3-IL-2002.90003

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: Ailon, Amit

Abstract: This study presents simple controllers for achieving trajectory tracking for the kinematic model of an Unmanned Aerial Vehicle (UAV) with bounded inputs. The proposed controllers are based on smooth bounded functions that can easily be implemented. The underlying stabilizing controller can be applied in control tasks of a group of UAVs. Relevant aspects concerning control strategies for formation flying missions are considered, and some results are demonstrated by means of numerical results.

Keywords: Autonomous Systems; Robust Nonlinear Control; Vehicle Monitoring, Diagnosis and Control

Identifier: 10.3182/20090616-3-IL-2002.00061

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: Chang, Michael; Davison, Edward J.

Abstract: In this paper, the multi-input multi-output robust servomechanism problem for sinusoidal reference and/or disturbance signals having possibly unknown magnitude and/or phase components is examined. For the situation where such sinusoidal harmonic components are calibrated, for instance, via a priori tuning methods, simple initialization results are presented to reduce undesirable transient responses, and can be applied advantageously in a continuous- or discrete-time setting. Using this framework, additional optimization techniques then are developed and presented to minimize potentially undesirable tuning transients. Simulations are given using these new control design results when applied to a conventional hard disk drive system, where multiple harmonic disturbances may arise due to, for example, disk eccentricity or clamping effects. A comparison with another commonly-used harmonic cancellation method demonstrates and emphasizes the practical advantages and benefits that can be attained when using the proposed solution approach.

Keywords: Computational Methods; Robotics

Identifier: 10.3182/20090616-3-IL-2002.00055

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: Smagina, Yelena; Sheintuch, Moshe

Abstract: We consider the stabilization of a rotating temperature pulse moving in a continuous asymptotic model of many connected chemical reactors organized in a loop with continuously switching of the feed point synchronously with the motion of the pulse solution. We use the switch velocity as control parameter and design it to follow the pulse: the switch velocity is formed at every step on-line using the discrepancy between the temperature at the front of the pulse and a set point. The resulting feedback controller, which can be regarded as a dynamic sampled-date controller, is designed using root-locus technique. Convergence conditions of the control law are obtained in terms of the zero structure (finite zeros, infinite zeros) of the related lumped model. The theoretical results are applied to keep a moving solution in the typical loop reactor in which a single exothermic reaction occurs and is confirmed by numerical simulations.

Keywords: Robust Control for Distributed Parameter Systems; Switched Systems; Chemical Systems

Identifier: 10.3182/20090616-3-IL-2002.00016

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: Dong, Daoyi; Petersen, Ian

Abstract: This paper formulates and solves a variable structure control problem for the state control of quantum systems. Following the concept of wavefunction controllability, we first present a specific quantum system which is wavefunction uncontrollable under the action of any one of two controllers with different fixed structures. However, we prove that the system is wavefunction controllable if the control input is allowed to switch between the two controllers. An extension and the potential applications of the proposed control strategy are briefly discussed and the general steps of variable structure control design for this class of quantum systems are also presented. The variable structure control scheme provides an alternative quantum engineering approach for the manipulation of quantum systems.

Keywords: Variable Structure Control; Robust Nonlinear Control; Chemical Systems

Identifier: 10.3182/20090616-3-IL-2002.00041

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009

Authors: None

Abstract:

Keywords:

Identifier: 10.3182/20090616-3-IL-2002.90002

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

Location: Dan Panorama Hotel, Israel

Start Date: Tue Jun 16 2009 - End Date: Thu Jun 18 2009