Authors: None

Abstract:

Keywords:

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00300

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: ---

Authors: None

Abstract:

Keywords:

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00301

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: ---

Authors: None

Abstract:

Keywords:

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00302

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: ---

Authors: Clarke, Francis

Abstract: This tutorial paper is devoted to the controllability and stability of control systems that are nonlinear, and for which, for whatever reason, linearization fails. We begin by motivating the need for two seemingly exotic tools: nonsmooth control-Lyapunov functions, and discontinuous feedbacks. Then, after a (very) short course on nonsmooth analysis, we build a theory around these tools. We proceed to apply it in various contexts, focusing principally on the design of discontinuous stabilizing feedbacks.

Keywords: Lyapunov Methods; Lyapunov Stability Methods; Stability

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00301

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 1-29

Authors: Mazenc, Frederic; Bernard, Olivier

Abstract: It is shown that, for any time-invariant exponentially stable linear system with additive disturbances, time-varying exponentially stable interval observers can be constructed. The technique of construction relies on the Jordan canonical form that any real matrix admits and on time-varying changes of coordinates for elementary Jordan blocks which lead to cooperative linear systems. The approach is applied to any non-linear system that can be written as the sum of a linear stable term, and of a non-linear term (including disturbances) for which known bounds exist.

Keywords: Observability and Observer Design; State Estimation and Applications; Biological and Biomedical Systems

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00081

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 30-35

Authors: Blesa, Joaquim; Puig, Vicenc; Saludes, Jordi; Vento, Jorge

Abstract: In this paper, a leak detection, isolation and estimation methodology in pressurized water pipe networks is proposed. The methodology is based on computing residuals which are obtained comparing measured pressures (heads) in selected points of the network with their estimated values by means of a Linear Parameter Varying (LPV) model and zonotopes. The structure of the LPV model is obtained from the non-linear mathematical model of the network. The proposed detection method takes into account modelling uncertainty using zonotopes. The isolation and estimation task employs an algorithm based on the residual fault sensitivity analysis. Finally, a typical water pipe network is employed to validate the proposed methodology. This network is simulated using EPANET software. Parameters of LPV model and their uncertainty bounded by zonotopes are estimated from data coming from this simulator. A leak scenario allows to assess the effectiveness of the proposed approach.

Keywords: Parameter Estimation.; Biological and Biomedical Systems

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00054

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 36-41

Authors: Le Bars, Fabrice; Bertholom, Alain; Sliwka, Jan; Jaulin, Luc

Abstract: This paper provides a new submarine experiment and shows the results of an interval SLAM (Simultaneous Localization And Mapping) method. The SLAM problem is cast into a constraint satisfaction problem where interval propagation algorithms are particularly efficient. The resulting method is applied to the localization of a submarine robot from the GESMA (Groupe d’Etudes Sous-Marines de l’Atlantique), the Daurade during an experiment in the Douarnenez bay, in Brittany (France).

Keywords: Robotics; State Estimation and Applications

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00083

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 42-47

Authors: Rauh, Andreas; Auer, Ekaterina; Aschemann, Harald

Abstract: Solving initial value problems (IVPs) for ordinary differential equations (ODEs) is a common task in many scientific fields. Over the last decades, several different verified techniques have been developed to compute enclosures of the exact result numerically. The obtained bounds are guaranteed to contain the corresponding solution to the IVP and can be used to verify whether a given control strategy is admissible with respect to state and input constraints. Ideally, we aim at calculating tight enclosures over sufficiently long time intervals for systems with uncertainties given as sets. However, the existing solvers are not always equal in attaining this goal. On the one hand, the quality of the obtained results depends strongly on the types of ODEs that describe a given dynamical system. On the other hand, a great influence of the considered uncertainties can be observed. Our general aim is to provide assistance in choosing an appropriate verified IVP solver with its most suitable `tuning parameters' for the application at hand. In this paper, we describe briefly the basics of verified IVP solvers. After a short introduction to a possible framework for the fair comparison of different approaches, we concentrate on possibilities to quantify the conservativeness introduced by verified solvers for problems with uncertainties.

Keywords: Numerical Methods; Robustness; Parameter Estimation.

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00162

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 48-53

Authors: Efimov, Denis; Raissi, Tarek; Zolghadri, Ali

Abstract: The paper deals with joint state and parameter estimation for nonlinear continuous-time systems. Based on a guaranteed LPV approximation, the problem of set observers design is recasted into more general adaptive observers design problem in order to avoid the exponential complexity obstruction usually met in the set-membership nonlinear estimation. The efficacy of the proposed set adaptive observer is demonstrated on a bioreactor example.

Keywords: Adaptive Observers; Dynamical Systems Techniques; Chemical Process

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00043

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 54-59

Authors: Kurzhanski, A.B.; Varaiya, Pravin P.

Abstract: This paper gives a concise description of a solution approach to the problem of output feedback control under unknown but bounded disturbances. It is based on combining dynamic programming with set-valued techniques and ranges from theoretical schemes to computational routes which indicate the possibility of treating the overall problem through finite-dimensional techniques. The results apply to nonlinear systems with more details for the linear case.

Keywords: H-infinity Control

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00133

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 60-65

Authors: Teel, Andrew R.; Marconi, Lorenzo

Abstract: This note presents a result on stabilization for a class of minimum phase, relative degree one hybrid systems. The note focuses on the situation where the derivative of the output is the sum of the input and a term that vanishes everywhere on the attractor of the zero dynamics except at finite number of (nonequilibrium) points.

Keywords: Hybrid Nonlinear Control Systems; Hybrid Nonlinear Systems; Lyapunov Methods

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00109

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 66-71

Authors: Prieur, Christophe; Tarbouriech, Sophie; Zaccarian, Luca

Abstract: We construct hybrid loops that augment continuous time control systems consisting in a continuous-time nonlinear plant in feedback with a (possibly non stabilizing) given nonlinear dynamic continuous-time controller. In particular, the arising hybrid closed-loops are guaranteed to follow the underlying continuous-time closed-loop dynamics when flowing and to jump in suitable regions of the closed-loop state space to guarantee that a positive definite function $V$ of the closed-loop state and/or a positive definite function $V_p$ of the plant-only state is non increasing along the hybrid trajectories. Sufficient conditions for the construction of these hybrid loops are given for the nonlinear case and then specialized for the linear case with the use of quadratic functions. The proposed approach is illustrated on a linear and a nonlinear example.

Keywords: Hybrid Nonlinear Systems; Stabilization; Lyapunov Methods

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00183

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 72-77

Authors: Ceragioli, Francesca; De Persis, Claudio; Frasca, Paolo

Abstract: It is well known that the consensus problem can be formulated in terms of a stabilization problem. In this note, we consider continuous-time average consensus dynamics: we discuss how quantization can be included in the system, and focus on one model, in which the agents' states are communicated through uniform quantizers. Solutions to the resulting system are defined in the Krasowskii sense, and results are given proving their convergence to conditions of practical consensus. To cope with potential chattering phenomena, which may be undesired in the applications, we propose the use of a hysteretic quantizer, and study the convergence properties of the resulting dynamics by a hybrid system approach.

Keywords: Quantized Feedback and Feedback with Communication Constraints; Hybrid Nonlinear Systems; Stabilization

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00068

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 78-83

Authors: Sailer, Rudolf; Wirth, Fabian R.

Abstract: We consider stabilization over communication channels with delays and packet loss. Using a variation of dynamic quantization an encoder/decoder scheme is presented which is able to achieve stabilization if a closed loop system exists which is ISS with respect to measurement errors. Conditions for stabilization require bounds on the long-term average throughput of the communication channel. In communication channels which can be modelled as Markov processes this can be guaranteed almost surely provided an ergodicity assumption is met.

Keywords: Quantized Feedback and Feedback with Communication Constraints; Stabilization; Input-to-state Stability

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00226

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 84-89

Authors: Polushin, Ilia G.; Dashkovskiy, Sergey

Abstract: A small gain approach for stability analysis of cooperative network-based force reflecting teleoperator systems is presented. The approach is based on a new version of input-to-output stability (IOS) nonlinear small gain theorem that is applicable to stability analysis of large-scale network-based interconnections. Using the small-gain theorem presented, we show that stability of the cooperative teleoperator system can always be achieved by choosing some of the system' gains appropriately.

Keywords: Small Gain Theorems; Robotics; Quantized Feedback and Feedback with Communication Constraints

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00240

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 90-95

Authors: Broucke, Mireille

Abstract: We study the reach control problem for affine systems on simplices, and the focus is on cases when it is known that the problem is not solvable by continuous state feedback. We examine from a geometric viewpoint the structural properties of the system which make continuous state feedbacks fail. This structure is encoded by so-called reach control indices, which are defined and developed in the paper.

Keywords: Switching Control; Hybrid Nonlinear Control Systems

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00253

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 96-101

Authors: Ricardo, Sandra; Respondek, Witold

Abstract: We study the geometry of mechanical control systems. A special class is distinguished: the class of geodesically accessible mechanical systems, for which the uniqueness of the mechanical structure is guaranteed (up to an extended point transformation). We characterise nonlinear control systems that are state equivalence to a system from that class and describe the canonical mechanical structure attached to it.

Keywords: Mechanical Systems; Dynamical Systems Techniques; Geometric Methods

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00291

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 102-107

Authors: Sarras, Ioannis; Acosta, Jose Angel; Ortega, Romeo; Mahindrakar, Arun D.

Abstract: In this paper a constructive approach to the stabilization of a desired equilibrium for a class of underactuated mechanical systems via the Immersion & Invariance methodology (I&I) is proposed. The design procedure shows that cases of mechanical systems with underactuation degree greater than one are included. This work generalizes the results recently reported by the authors, where an approach to obviate the solution of the corresponding PDEs for a class of nonlinear systems was proposed. Finally, our approach is successfully applied to the inertia wheel pendulum system and an interesting connection with the Interconnection and Damping Assignment Passivity-Based Control (IDA-PBC) is revealed.

Keywords: Mechanical Systems; Stabilization

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00262

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 108-113

Authors: Hauser, John

Abstract: We consider the question of whether the pendubot system is controllable about the kinematic singularity equilibrium point, where linear controllability is lost. Although accessibility is easily confirmed using Lie bracket of the system vector fields, conclusions about the controllability of the system appear to be quite challenging, since the system is not driftless and doesn't appear to be homogeneous. In this paper, we tackle the question head on and prove controllability of a second order approximation to the system by constructing a family of linearly controllable trajectory loops based at the equilibrium. The structure of the approximation and the selected control input allow us to explicitly integrate the approximate system equations of motion. The trajectory construction exploits a particular time reversal symmetry shared by the pendubot and its second order approximation.

Keywords: Mechanical Systems; Optimal Control; Stability

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00278

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 114-118

Authors: Notarstefano, Giuseppe; Hauser, John

Abstract: In this paper we introduce and study a novel model of a Tilt-Rotor VTOL aircraft. The aircraft is structured as a blended wing body equipped with a tilting rotor (the propulsion unit) that gives the vehicle the capability of vertical take off and transition to a forward flight configuration. This model captures the main features of novel tilt-rotor aircraft architectures with more challenging control and maneuvering capabilities. We introduce a complex nine degrees of freedom model of the aircraft to explore the dynamics and the maneuvering capabilities of the vehicle. We perform an analysis of the equilibrium manifold of the aircraft (namely a parametrized family of trimming trajectories) and, as main contribution of the paper, we introduce a set of optimal control based strategies to explore the trajectory manifold of the vehicle in order to generate non-stationary and highly aggressive trajectories. In particular, we provide numerical computations showing how to generate a trajectory for transitions from near hover to forward flight.

Keywords: Mechanical Systems; Optimal Control; Aerospace

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00182

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 119-124

Authors: Miranda La Hera, Pedro Xavier; Freidovich, Leonid; Shiriaev, Anton; Mettin, Uwe

Abstract: The planar motion to traverse from point to point with a ballbot is discussed. Our aim is to propose an analytical method to plan motions that can be robustly executed by feedback control. The approach is based on defining geometric virtual relations among the generalized coordinates. These relations form the basis of a reparametrization of the system dynamics for motion planning, and an introduction of coordinates transverse to the desired trajectories useful for controller design. Results of numerical simulation are presented to illustrate the performance and robustness of the closed-loop system.

Keywords: Mechanical Systems; Time Optimal Control; Geometric Methods

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00185

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 125-130

Authors: Poljak, Daniel; Schindele, Dominik; Antritter, Felix; Aschemann, Harald; Hillermeier, Claus

Abstract: A nonlinear controller structure for an overhead crane is designed and implemented on a crane plant. The energy based stabilizing controller part is derived by the method of Controlled Lagrangians. In that framework, kinetic and potential shaping is performed and so-called general matching conditions are employed. Control parameters well suited for the practical implementation are found by optimization using the linearization of the closed loop system. Nonlinear damping effects are counteracted in the overall controller structure by feedforward compensation and a reduced nonlinear disturbance observer.

Keywords: Mechanical Systems; Model Based Control; Geometric Methods

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00134

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 131-136

Authors: Zhao, Jun; Hill, David J.; Liu, Tao

Abstract: The global synchronization problem for general dynamical networks with non- identical nodes is studied by introducing multiple V -Lyapunov functions. In such a network, the coupling strength, inner coupling matrix and outer coupling matrix are all allowed to be state-dependent and nonlinear. A global synchronization criterion is proposed in terms of matrix norms and eigenvalues of some lower-dimensional matrices. We also study the problem of how to achieve global synchronization by design of controllers under the scheme of multiple V - Lyapunov functions. The control action is regarded as a re-shape of outer coupling topology and the associated controllers are designed. In particular, a method of global synchronization by adding or removing a certain number of links is proposed.

Keywords: Anti-control and Synchronization.; Complex Network; Algebraic Methods

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00113

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 137-142

Authors: Liu, Bin; Liu, Tao; Hill, David J.

Abstract: This paper investigates the delayed impulsive control for synchronization of discrete-time complex dynamical networks (CDNs). The original dynamical network is complex with respect to the unstable or chaotic nodes, coupling time-delays, and time-varying, and thus it does not have the synchronization property. A synchronization scheme of impulsive control with delayed signal inputs is proposed for the discrete-time CDNs via hybrid discrete-time. By utilizing methods such as matrix spectrum and eigenvalue theory and dwell time, global uniform exponential stability (GUES) criteria are derived for the error system, under which exponential synchronization is achieved for the CDN. Moreover, by only delayed impulsive control signals, the exponential synchronization is realized for the CDN with coupling time-delays. Finally, two examples with numerical simulations are worked out for illustration.

Keywords: Complex Network; Anti-control and Synchronization.; Hybrid Nonlinear Control Systems

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00013

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 143-148

Authors: Bürger, Mathias; Schmidt, Gerd Simon; Allgower, Frank

Abstract: A group coordination problem is studied, where different agents are modeled as double integrator systems. Each agent aims to minimize a convex optimization function on the velocity. The coordination objective, studied in this note, is to find distributed coordination laws, such that the agents achieve a common velocity, which is the minimizer of the sum of all objective functions, while achieving a certain inter-agent spacing. Two different fully distributed coordination algorithms are proposed and analyzed. The algorithms combine ideas from distributed optimization and group coordination.

Keywords: Complex Network; Optimization and Scheduling; Lyapunov Methods

Digital Object Identifier (DOI): 10.3182/20100901-3-IT-2016.00176

Conference: 8th IFAC Symposium on Nonlinear Control Systems (2010)

Location: University of Bologna, Italy

Start Date: Wed Sep 01 2010 - End Date: Fri Sep 03 2010

Page Numbers: 149-154