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FrC08.1 A first principle model for multiphase slugging flow in vertical risers
"... Abstract — In this paper, we propose a simple model to represent the slugging flow regime appearing in vertical risers. We consider a one dimensional twophase flow composed of a liquid phase and a gaseous compressible phase. The presented model can be applied to a wide class of systems, ranging fro ..."
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Abstract — In this paper, we propose a simple model to represent the slugging flow regime appearing in vertical risers. We consider a one dimensional twophase flow composed of a liquid phase and a gaseous compressible phase. The presented model can be applied to a wide class of systems, ranging from pure vertical risers to more complex geometries such as those found on actual sub sea petroleum facilities. Following ideas from the literature, we introduce a virtual valve located at the bottom of the riser. This allows us to reproduce observed periodic regimes. It also brings insight into the physics of the slugging phenomenon. Most importantly, this model reveals relatively easy to tune and seems suitable for control design. A tuning methodology is proposed along with a proof of the existence of a limit cycle under simplifying assumptions. I.
Leeuwen. State and parameter estimation for systems in noncanonical adaptive observer form
 In Proceedings of the 17th IFAC World Congress on Automatic Control
, 2008
"... Abstract: We consider the problem of state and parameter reconstruction for uncertain dynamical systems that cannot be transformed into the canonical adaptive observer form. The uncertainties are allowed to be both linearly and nonlinearly parameterized functions of state and time. We provide a tech ..."
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Abstract: We consider the problem of state and parameter reconstruction for uncertain dynamical systems that cannot be transformed into the canonical adaptive observer form. The uncertainties are allowed to be both linearly and nonlinearly parameterized functions of state and time. We provide a technique that allows successful reconstruction of uncertain state and parameters for a broad range of dynamical systems that belong to this class. In contrast to conventional approaches our technique is based on the concepts of weakly attracting sets, and nonuniform convergence and Poisson stability rather than the notion of Lyapunov stability. Relevance of the proposed approach to the domains of control and system identification is illustrated with examples.
Summationtype conditions for uniform asymptotic convergence in discretetime systems: applications in identification
, 2005
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Nonlinear attitude estimation using active vision and inertial measurements
 In 48th IEEE Conference on Decision and Control, Shangai
, 2009
"... Abstract—In this paper we consider the problem of estimating the attitude of a rigid body equipped with a triad of rate gyros and a pan and tilt camera. The nonlinear attitude observer integrates angular velocity measurements from rate gyros, with images of a planar scene provided by the camera. By ..."
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Abstract—In this paper we consider the problem of estimating the attitude of a rigid body equipped with a triad of rate gyros and a pan and tilt camera. The nonlinear attitude observer integrates angular velocity measurements from rate gyros, with images of a planar scene provided by the camera. By exploiting directly sensor information, i) a stabilizing feedback law is introduced and the exponential convergence to the origin of the estimation errors is shown; ii) an active vision system is proposed that relies on an imagebased exponentially ISS control law for the camera pan and tilt angular rates to keep the features in the image plane. The discrete time implementation of the observer makes use of recent results in geometric numeric integration to preserve the rotation matrix properties. Simulated and experimental results demonstrate the effectiveness and applicability of the proposed solution. I.
Adaptive Observers and Parametric Identification for Systems in Noncanonical Adaptive Observer Form
, 903
"... We consider the problem of asymptotic reconstruction of the state and parameter values for dynamical systems that cannot be transformed into the canonical adaptive observer form. A solution to this problem is proposed for a class of systems for which the unknowns are allowed to be nonlinearly parame ..."
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We consider the problem of asymptotic reconstruction of the state and parameter values for dynamical systems that cannot be transformed into the canonical adaptive observer form. A solution to this problem is proposed for a class of systems for which the unknowns are allowed to be nonlinearly parameterized functions of state and time. Going beyond asymptotic Lyapunov stability, we provide for this class of systems a reconstruction technique, based on the concepts of weakly attracting sets, nonuniform convergence, and Poisson stability. Key words: Adaptive observers, nonlinear parametrization, weakly attracting sets, unstable attractors, nonlinear systems, Poisson stability 1
Modelbased Control of Automotive Engines and Aftertreatment Devices
"... Abstract: As environmental requirements on automotive vehicle emissions have steadily increased over the last decades, embedded control technology to perform realtime management of the driver’s requests has appeared as a key technology and has become ubiquitous. Today, every subsystem that is found ..."
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Abstract: As environmental requirements on automotive vehicle emissions have steadily increased over the last decades, embedded control technology to perform realtime management of the driver’s requests has appeared as a key technology and has become ubiquitous. Today, every subsystem that is found under the hood is controlled, most often in closedloop mode. A key factor in the development of a new engine or a new vehicle is the duration of its design cycle. The design and tuning of all the intricate control loops is very timeconsuming. One of the main reasons for this is that tuning procedures are often used to compensate for certain unmodeled effects such as neglected couplings of dynamic variables. In this talk, we explain how models can be used to reduce expensive calibration time significantly. As will be shown in the light of several experiments (involving airpath, fuelpath, and aftertreatment systems), simple models bring effective and practical solutions involving mature tools from nonlinear control theory. 1.
Implementation of a Nonlinear Attitude Estimator for Aerial Robotic Vehicles
"... Abstract—Attitude estimation is a key component of the avionics suite of any aerial robotic vehicle. This paper details theoretical and practical solutions in order to obtain a robust nonlinear attitude estimator for flying vehicles equipped with lowcost sensors. The attitude estimator is based on ..."
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Abstract—Attitude estimation is a key component of the avionics suite of any aerial robotic vehicle. This paper details theoretical and practical solutions in order to obtain a robust nonlinear attitude estimator for flying vehicles equipped with lowcost sensors. The attitude estimator is based on a nonlinear explicit complementary filter that has been significantly enhanced with an effective gyrobias compensation via the design of an antiwindup nonlinear integrator. A measurement decoupling strategy is proposed in order to make roll and pitch estimation robust to magnetic disturbances that are known to cause errors in yaw estimation. In addition, the paper discusses the fixedpoint numerical implementation of the algorithm. Finally, simulation and experimental results confirm the performance of the proposed method. Index Terms—attitude estimation, nonlinear observer, gyrobias compensation, antiwindup integrator, magnetic disturbance, unmanned aerial vehicle I.
ThA09.4 Airpath Control of a SI Engine with Variable Valve Timing Actuators
"... Abstract — We address the control of the airpath of a turbocharged ..."
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