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Hybrid Feedback Stabilization of Systems With Quantized Signals
"... This paper is concerned with global asymptotic stabilization of continuoustime systems subject to quantization. A hybrid control strategy originating in earlier work (R. W. Brockett and D. Liberzon, Quantized feedback stabilization of linear systems, IEEE Trans. Automat. Control, 45:12791289, 2000 ..."
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Cited by 75 (11 self)
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This paper is concerned with global asymptotic stabilization of continuoustime systems subject to quantization. A hybrid control strategy originating in earlier work (R. W. Brockett and D. Liberzon, Quantized feedback stabilization of linear systems, IEEE Trans. Automat. Control, 45:12791289, 2000) relies on the possibility of making discrete online adjustments of quantizer parameters. We explore this method here for general nonlinear systems with general types of quantizers affecting the state of the system, the measured output, or the control input. The analysis involves merging tools from Lyapunov stability, hybrid systems, and inputtostate stability.
Stability of modelbased networked control systems with timevarying transmission times
 In Proc. of the 2003 Amer. Contr. Conf
, 2004
"... Abstract—In modelbased networked control systems (MBNCSs), an explicit model of the plant is used to produce an estimate of the plant state behavior between transmission times. In this paper, the stability of MBNCSs is studied when the controller/actuator is updated with the sensor information at ..."
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Cited by 60 (1 self)
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Abstract—In modelbased networked control systems (MBNCSs), an explicit model of the plant is used to produce an estimate of the plant state behavior between transmission times. In this paper, the stability of MBNCSs is studied when the controller/actuator is updated with the sensor information at nonconstant time intervals. Networked control systems with transmission times that are varying either within a time interval or are driven by a stochastic process with identically independently distributed and Markovchain driven transmission times are studied. Sufficient conditions for Lyapunov stability are derived. For stochastically modeled transmission times almost sure stability and meansquare sufficient conditions for stability are introduced. Index Terms—Modelbased networked control systems (MBNCSs), stochastic stability, timevarying transmission times. I.
Analysis and synthesis of switched linear control systems
, 2005
"... Switched linear systems have a long history of interest in the control community, and have attracted considerable attention recently because they are not only practically relevant, but also tangible with the rich results in the linear system theory. Rapid progress in the field has generated many new ..."
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Cited by 49 (3 self)
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Switched linear systems have a long history of interest in the control community, and have attracted considerable attention recently because they are not only practically relevant, but also tangible with the rich results in the linear system theory. Rapid progress in the field has generated many new ideas and powerful tools. This paper provides a concise and timely survey on analysis and synthesis of switched linear control systems, and presents the basic concepts and main properties of switched linear systems in a systematic manner. The fundamental topics include (i) controllability and observability, (ii) system structural decomposition, (iii) feedback controller design for stabilization, and (iv) optimal control.
Inputtostate stability of networked control systems
 Automatica
, 2004
"... Abstract — A new class of uniformly globally asymptotically stable (UGAS) protocols in networked control systems (NCS) is considered. It shown that if the controller is designed without taking into account the network so that it yields inputtostate stability (ISS) with respect to external disturban ..."
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Cited by 33 (1 self)
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Abstract — A new class of uniformly globally asymptotically stable (UGAS) protocols in networked control systems (NCS) is considered. It shown that if the controller is designed without taking into account the network so that it yields inputtostate stability (ISS) with respect to external disturbances (not necessarily with respect to the error that will come from the network implementation), then the same controller will achieve semiglobal practical ISS for the NCS when implemented via the network with a UGAS protocol. The adjustable parameter with respect to which semiglobal practical ISS is achieved is the socalled maximal allowable transfer interval (MATI) between transmission times. I.
Rendezvous without Coordinates
"... Abstract — We study minimalism in sensing and control by considering a multiagent system in which each agent moves like a Dubins car and has a limited sensor that reports only the presence of another agent within some sector of its windshield. Using a very simple quantized control law with three va ..."
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Cited by 20 (3 self)
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Abstract — We study minimalism in sensing and control by considering a multiagent system in which each agent moves like a Dubins car and has a limited sensor that reports only the presence of another agent within some sector of its windshield. Using a very simple quantized control law with three values, each agent tracks another agent assigned to it by maintaining that agent within this windshield sector. We use Lyapunov analysis to show that by acting autonomously in this way, the agents will achieve rendezvous if the initial assignment graph is connected. A distinguishing feature of our approach is that it does not involve any estimation procedure aimed at reconstructing coordinate information. Our scenario thus appears to be the first example in which an interesting task is performed with extremely coarse sensing and control, and without state estimation. The system was implemented in computer simulation, accessible through the Web, of which the results are presented in the paper. (a) (b)
Quantized control via locational optimization
 IEEE TRANS. AUTOMAT. CONTROL
, 2008
"... This paper studies state quantization schemes for feedback stabilization of control systems with limited information. The focus is on designing the least destabilizing quantizer subject to a given information constraint. We explore several ways of measuring the destabilizing effect of a quantizer on ..."
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Cited by 8 (1 self)
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This paper studies state quantization schemes for feedback stabilization of control systems with limited information. The focus is on designing the least destabilizing quantizer subject to a given information constraint. We explore several ways of measuring the destabilizing effect of a quantizer on the closedloop system, including (but not limited to) the worstcase quantization error. In each case, we show how quantizer design can be naturally reduced to a version of the socalled multicenter problem from locational optimization. Algorithms for solving such problems are discussed. In particular, an iterative solver is developed for a novel weighted multicenter problem which most accurately represents the least destabilizing quantizer design.
Persis. Discontinuous stabilization of nonlinear systems: Quantized and switching control
 Systems & Control Letters
"... In this paper we consider the classical problem of stabilizing nonlinear systems in the case the control laws take values in a discrete set. First, we present a robust control approach to the problem. Then, we focus on the class of dissipative systems and rephrase classical results available for thi ..."
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Cited by 8 (1 self)
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In this paper we consider the classical problem of stabilizing nonlinear systems in the case the control laws take values in a discrete set. First, we present a robust control approach to the problem. Then, we focus on the class of dissipative systems and rephrase classical results available for this class taking into account the constraint on the control values. In this setting, feedback laws are necessarily discontinuous and solutions of the implemented system must be considered in some generalized sense. The relations with the problems of quantized and switching control are discussed.
Visionbased navigation through urban canyons
 Journal of Field Robotics
, 2009
"... We address the problem of navigating unmanned vehicles safely through urban canyons in two dimensions using only visionbased techniques. Two commonly used visionbased obstacle avoidance techniques (namely stereo vision and optic flow) are implemented on an aerial and a groundbased robotic platfor ..."
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Cited by 6 (0 self)
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We address the problem of navigating unmanned vehicles safely through urban canyons in two dimensions using only visionbased techniques. Two commonly used visionbased obstacle avoidance techniques (namely stereo vision and optic flow) are implemented on an aerial and a groundbased robotic platform and evaluated for urban canyon navigation. Optic flow is evaluated for its ability to produce a centering response between obstacles, and stereo vision is evaluated for detecting obstacles to the front. We also evaluate a combination of these two techniques, which allows a vehicle to detect obstacles to the front while remaining centered between obstacles to the side. Through experiments on an unmanned ground vehicle and in simulation, this combination is shown to be beneficial for navigating urban canyons, including Tjunctions and 90deg bends. Experiments on arotorcraftunmannedaerialvehicle,whichwasconstrainedtotwodimensionalflight, demonstrate that stereo vision allowed it to detect an obstacle to the front, and optic flow allowed it to turn away from obstacles to the side. We discuss the theory behind these techniques, our experience in implementing them on the robotic platforms, and their suitability to the urban canyon navigation problem. C ○ 2009 Wiley Periodicals, Inc. 1.
Randomized Algorithms for Quadratic Stability of Quantized SampledData Systems
"... We present a novel development of randomized algorithms for quadratic stability analysis of sampleddata systems with memoryless quantizers. The specific randomized algorithm employed generates a quadratic Lyapunov function and leads to realistic bounds on the performance of such systems. A key feat ..."
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Cited by 6 (1 self)
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We present a novel development of randomized algorithms for quadratic stability analysis of sampleddata systems with memoryless quantizers. The specific randomized algorithm employed generates a quadratic Lyapunov function and leads to realistic bounds on the performance of such systems. A key feature of this method is that the characteristics of quantizers are exploited to make the algorithm computationally efficient. 1
ModelBased Networked Control Systems: Stability
, 2002
"... In this report the control of continuous linear plants where the state sensor is connected to a linear controller/actuator via a network is addressed. The work focuses on reducing the network usage using knowledge of the plant dynamics. Specifically, the controller uses an explicit model of the plan ..."
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Cited by 6 (3 self)
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In this report the control of continuous linear plants where the state sensor is connected to a linear controller/actuator via a network is addressed. The work focuses on reducing the network usage using knowledge of the plant dynamics. Specifically, the controller uses an explicit model of the plant that approximates the plant dynamics and makes possible stabilization of the plant even under slow network conditions. Necessary and sufficient conditions for stability are derived for the presented setup in terms of the update time h and the parameters of the plant and of its model. The deterioration of behavior when either h or the modeling error increase is explicitly shown.