http://www.ifac-papersonline.net/ en Copyright 07:57 PM Wednesday 22, 2012 IFAC-PapersOnline http://www.ifacpapersonline.com 07:57 PM Wednesday 22, 2012 07:57 PM Wednesday 22, 2012 ET webmaster@ifac-papersonline.net webmaster@ifac-papersonline.net http://www.ifac-papersonline.net/Detailed/44793.html 04:00 PM Wednesday 31, 1969 A new approach to the controllability and observability properties, based on controllability and observability matrices links, is considered. The approach is based on matrices integrals expansion Lemma and properties of the matrices function convolution in complex plane. Coefficients of characteristic equations and Faddeev’s matrices in the resolvent expansion of the system dynamic matrix play a dominant role in matrices integrals expansion forming. The gramians expansion on dynamic system matrix spectrum provide a new notion for the solutions of the Lyapunov and Sylvester equations. The results are illustrated by the example for two-zones furnace control. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44761.html 04:00 PM Wednesday 31, 1969 This paper formulates a linear parameter varying (LPV) model for a semi-active quarter of car. The formulation is based on a new MR damper model which is based on the measurement of the maximum deflection velocity and validated with experimental data. In this device, the saturation is dynamical and it depends on the maximum current to apply and the velocity deflection. One scheduling parameter includes the variation of the damping coefficient and the dynamic saturation of the MR damper decreasing the conservatism of the model. Open and H1 closed loop frequency responses comparison of the proposed model and a nonlinear QoC is done. In open loop, the results shows that the new structure for the model is feasible. For closed loop, the nonlinear saturation has a windup effect below 5 Hz. In both tests, the applied current always is realistic. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44833.html 04:00 PM Wednesday 31, 1969 In this paper we consider the problem of driving to zero by means of state feedback the state of a nonlinear plant when only an approximate model of the plant is known and the information about its state is sampled. To this aim, we develop a specific model-based control scheme and, under suitable hypotheses, we give a sufficient condition, in terms of length of the sampling interval and of other design parameters, for achieving the control objective. The present results improve the applicability of previous ones, obtained, in the same line, by the authors. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44749.html 04:00 PM Wednesday 31, 1969 The paper presents an extension of the mixed Sky-hook and ADD to Magneto-Rheological dampers. Firstly, a semi-active automotive suspension equipped with a nonlinear Magneto-Rheological damper is introduced. The interest of this nonlinear model is that the bi-viscous and hysteretic behaviors of MR dampers can be taken into account in the controller design. Hence, the designed controller is more adaptive with real MR dampers. Finally, the new mixed Sky-hook and ADD algorithm for MR dampers is proposed to enhance the passenger comfort. The performances of the proposed control method are then analyzed, based on simulations on a nonlinear vehicle model. The results shows that the Mixed Sky-Hook and ADD can be successfully extended to Magneto-Rheological dampers. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44775.html 04:00 PM Wednesday 31, 1969 The paper is concerned with defining families of smooth functions that can be used for the approximation of impulsive types of solutions for linear systems. We review the different types of approximations of distributions in terms of smooth functions and explains their significance in the characterization of system properties where impulses were used for their characterisation. For controllable systems, we establish an interesting relation between the time t and sigma (volatility) in the approximation of distributional solutions. An algorithm is then proposed for the calculation of the coefficients of the input required to minimize the distance of our desired target state before and after approximation is proposed. The optimal choice of sigma is derived for a predetermined time t for the state transition. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44741.html 04:00 PM Wednesday 31, 1969 http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44853.html 04:00 PM Wednesday 31, 1969 In this paper we study two mixed (finite-dimensional and infinite dimensional) systems -- a flexible beam on a moving cart and a fluid tank mounted on a moving cart. The cart is connected to ordinary dampers, which dissipate the energy. The ultimate objective of this work is to ensure that all the energy of the infinite dimensional system (due to any disturbances){flows} into the dampers and gets dissipated. We show that this is possible under certain conditions and that boundary damping alone is sufficient to bring the composite system to rest. We adopt the{port-Hamiltonian approach}for our analysis, which allows us to look at the composite plant as a power conserving interconnection of infinite and finite dimensional systems. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44829.html 04:00 PM Wednesday 31, 1969 An antagonism actuated by a pair of pneumatic muscle actuators has recently become an alternative basic unit for developing humanoid robots or robotic manipulators. A manipulator may consist of one or more of such basic units. One unit can be ready for a 1-dof ‘soft’ manipulator, which exhibits the advantageous characteristics contributed by the individual muscles such as compliance, high power-weight ratios, high volume-weight ratios, etc. However, hysteresis and muscle creep are the most drawbacks that limit the widespread use of these actuators. This paper presents a new approach to model the hysteresis in a basic manipulator constructed by a pair of Festo fluidic muscles. The experimental results show that the manipulator hysteresis has the same behaviours as those found in the individual muscles, and that this hysteresis is well described by the Maxwell-slip model. The creep effect is factorized and incorporated into the constraint torque model, resulting in a stationary extracted hysteresis loop. The proposed model therefore performs very well as in the prediction of the torque-angle hysteresis not only at an arbitrary angular trajectory but also at any moment of the creep conditions. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44781.html 04:00 PM Wednesday 31, 1969 We explore the signal flow graph as a setup for visualizing and analyzing interconnected systems. Two operations for facilitating interpretation of signal flow graphs are defined. These are hiding of unimportant nodes and elimination of self-references and it is shown that the operations commute under some conditions and that the hiding operation preserves the physical structure of the system in a certain sense. Also, the Loop Gain Index (LGI) is introduced as a measure of the relative importance of the vertices in terms of dynamic behavior of the interconnected system. The LGI is illustrated with a numerical example. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44763.html 04:00 PM Wednesday 31, 1969 In this paper, ns-2 simulations and related comparisons of four different PI controllers designed for TCP/AQM networks will be presented. The simulations are performed for various scenarios. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44835.html 04:00 PM Wednesday 31, 1969 This paper presents the consensus problem in the framework of optimal control. Our aim is to synchronize a set of identical linear systems. We propose a cost which penalizes mutual differences between the states of these systems. The feedback matrix resulting from this linear quadratic control problem represents the interconnection network which synchronizes the systems. In general the interconnection structure is of the all-to-all type. We show that it is possible to devise an LQR problem in which the cost results in an interconnection structure representing ring coupling. Care has to be taken that the effect of the feedback control is restricted to synchronizing the systems, i.e. when the systems are synchronized, the feedback control signal is required to be equal to zero. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44787.html 04:00 PM Wednesday 31, 1969 We consider the control of a class of implicit systems arising from discrete-event models for production or telecommunication systems. Such systems are subject to polyhedral constraints, and one is interested in the existence, the unicity, and the computation, of solutions respecting the constraints. Necessary and sufficient conditions are described, for the existence of a control law so that for the closed-loop systems, a unique solution exists, and a given polyhedron is invariant. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44785.html 04:00 PM Wednesday 31, 1969 In this paper we view a classical periodic state space system as a behavioral system and compare the properties of state controllability and state reconstructibility with behavioral controllability and behavioral reconstructibility, respectively. We show that, like it happens for the time-invariant case, the behavioral controllability/reconstructibility of a periodic state space system is equivalent to its complete state controllablity/reconstructibility. Further, using the classical definition of a dual state space system and our behavioral definitions, we prove that behavioral controllability and behavioral reconstructibility are also dual properties in the periodic case. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44825.html 04:00 PM Wednesday 31, 1969 Volterra series expansions have been extensively used to solve and represent the dynamics of weakly nonlinear finite dimensional systems. Such expansions can be recovered by using the regular perturbation method and choosing the input of the system as the perturbation: the state (or the output) is then described by a series expansion composed of homogeneous contributions with respect to the input, from which kernels of convolution type can be deduced. This paper provides an extension (based on this approach) to a class of semilinear infinite dimensional systems, nonlinear in state and affine in input. As a main result, computable bounds of the convergence radius of the series are established. They characterize domains on which the series defines a mild solution of the system. The convergence criterion is established for bounded signals (infinite norms on finite or infinite time intervals) as follows: first, norm estimates of the series expansion terms are derived; second, the singular inversion theorem is used to deduce an easily computable bound of the convergence radius. In the formalism proposed here, non zero initial conditions can be also considered as a perturbation so that no precomputation of nominal trajectories is required in practice. The relevance of the method is illustrated on an academic example. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44783.html 04:00 PM Wednesday 31, 1969 In this paper, we show how suitable operatorial transformations can be used to simplify non local singular dynamic models. First, some basic notions on trajectories, operators and dynamic problems are introduced. Second, the diffusive transformation of non local models is briefly exposed. Then, time-scale transformations are introduced and some essentials properties are stated; the desingularization of models (in general non time local) is then studied. Finally, those transformations are applied on a singular implicit and non local flame model. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44779.html 04:00 PM Wednesday 31, 1969 In this paper the notion dimension of strong structural controllable subspaces of structured linear systems is introduced and a method for the determination is given. This proposed dimension is a lower bound for the dimensions of the controllable subspaces of all parameterized systems with the same structure. For this purpose the existing concepts of structural and strong structural controllability are revised and an algebraic characterization of the dimension of the strong structural controllable subspace is given. Furthermore, a new structured–based upper bound for the number of uncontrollable eigenvalues at zero is presented. Finally, the proposed algebraic criteria are applied to the controllability analysis of a linear drivetrain model of a parallel hybrid electric vehicle. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44757.html 04:00 PM Wednesday 31, 1969 The disturbance decoupling and the simulteneous disturbance and input - output decoupling problems for singular systems are considered in the context of the matrix fraction description (MFD) of the system. Solvability conditions are obtained in terms of the composite matrix of a column reduced MFD of the system, a characterisation of the fixed poles of both problems is given and it is shown that the remaining poles can be arbitrarily assigned. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44791.html 04:00 PM Wednesday 31, 1969 Mathematical technicalities, which are involved in the modern theory of non-linear control systems, many times prevents a wider use of the impressive theoretical results in practice. Attempts to overlap this gap between theory and practice are usually more than welcome and form the main scope of our interest in this work. An important control problem given by the disturbance decoupling is studied for a real laboratory model of coupled tanks. It is shown that the theoretical solution to the disturbance decoupling problem does not satisfy practical control requirememts. Accordingly, the solution is modified and yields a nonlinear controller with the distrubance decoupling. Experiments on the real plant, verifying and comparing the results with and without the disturbance decoupling, are included as well. It is shown that the disturbances practically do not affect the system output. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44755.html 04:00 PM Wednesday 31, 1969 The theory of constant polynomial combinants has been well developed and it is linked to the linear part of the constant Determinantal Assignment problem [1] that provides the unifying description of the pole and zero assignment problems in Linear Systems. Considering the case of dynamic pole, zero assignment problems leads to the emergence of dynamic polynomial combinants. This paper aims to develop the fundamentals of the theory of polynomial combinants by examining issues of their parameterization of dynamic polynomial combinants according to the notions of order and degree. Central to this study is the link of dynamic combinants to the theory of “Generalised Resultants”. The paper provides a description of the key spectral assignment problems, derives the conditions for arbitrary assignability of spectrum and introduces a complete parameterization of combinants and respective Generalised Resultants which is crucial for studying the minimal degree and order spectrum assignability. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44769.html 04:00 PM Wednesday 31, 1969 In this paper, the study of the finite structure of linear time varying systems modelled by bond graph is proposed with different approaches. Since from the bond graph model, different kind of mathematical relations can be directly derived, such as the state space representation, input-output relations or algebraic relations between variables defined either in a vector space or in a module (algebraic approach), different theoretical concepts can be used together in order to point out the finite structure of the model. In case of LTV models, mathematical calculus are not easily implemented because of the non commutativity between operations, thus a graphical methodology is pointed out directly on the bond graph representation. Even if finite zeros cannot be derived in each case, mathematical relations between variables which are related to the torsion module associated to the zeros are pointed out. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44771.html 04:00 PM Wednesday 31, 1969 When the almost disturbance decoupling problem (ADDP) is solvable, some poles of the closed loop system are fixed for any state feedback solution. In Zou and Malabre (2009c), the authors have characterized them by means of some invariant zeros but in the particular case of (A,B)-controllable systems. As a complement, here, we give the characterization of the fixed poles of ADDP for the general case, namely without any controllability assumption. We also propose a method to solve the ADDP for this general case, as well as a numerical example to illustrate our contributions. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44841.html 04:00 PM Wednesday 31, 1969 This paper deals with the problem of freeway traffic control through ramp metering to enhance their efficiency. The traffic is often modeled by a nonlinear hyperbolic conservation laws that may develop and propagate shock waves. The Cell Transmission model (CTM) developed in (Daganzo [1994]),(C. F. Daganzo [1995]) is taken in this work since linear control tools can be used for analysis and control design. This model is extended with parametric uncertainties. A hierarchical control scheme with two levels is considered. The rst level gives the optimal densities to apply on the freeway. The second level is charged for compensating local parametric uncertainties and disturbances (on-ramp demands, boundary conditions). These controllers are designed using switching control theory. A real-data based simulation is used to validate the effectiveness of the proposed control approach. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44851.html 04:00 PM Wednesday 31, 1969 In this paper, we show how the so-called diffusive representation can be used in order to identify nonlinear Volterra models of the form $H(partial_t)X=f(u,X)+v$. Several methods are described, all being based on a suitable parameterization of $H(partial_t)$ by means of its $gamma$-symbol. Following this idea, the complex dynamic nature of $H(partial_t)$ can be summarized by a few parameters on which the identification of the dynamic part of the model will focus. For illustration, we implement the methods on a concrete numerical example. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44839.html 04:00 PM Wednesday 31, 1969 The present paper extends the concept of Input-Output Finite Time Stability (IO-FTS) to a class of hybrid systems, namely Impulsive Dynamical Linear Systems, which are systems that exhibit jumps in the state trajectory. Sufficient conditions are given for the analysis of IO-FTS and for the design of a static state feedback controller, guaranteeing IO-FTS of the closed loop system. The presented results require to solve feasibility problems involving Difference/Differential Linear Matrix Inequalities, which can be solved numerically in an efficient way by using off-the-shelf optimization tools, as illustrated by the proposed examples. http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif http://www.ifac-papersonline.net/Detailed/44739.html 04:00 PM Wednesday 31, 1969 http://www.ifac-papersonline.net/static/luna/images/ifac/icon-download.gif