The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Xudong Ye - One of the best experts on this subject based on the ideXlab platform.
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cooperative control of multiple heterogeneous agents with unknown high Frequency Gain signs
Systems & Control Letters, 2014Co-Authors: Junmin Peng, Xudong YeAbstract:Abstract In this paper, we investigate the cooperative control of networked agents with unknown high-Frequency-Gain signs. A Nussbaum-type adaptive controller is designed for each agent such that consensus of the network can be achieved while all signals in the overall system maintain bounded. The distributed controller for each agent has two parts: neighborhood error between itself and the neighbors and a Nussbaum-type item for seeking control direction adaptively. The argument of the Nussbaum-type function is tuned on line via an appropriately designed update law. It is proved that when the undirected graph is connected or the balanced digraph is weakly connected, consensus of the network can be realized. Furthermore, a distributed asymptotic regulator is proposed to regulate the overall system to the equilibrium. Simulation results are presented to verify the effectiveness of the proposed controllers.
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Decentralized adaptive output-feedback stabilization of large-scale nonlinear systems with time-varying delays and unknown high-Frequency-Gain signs
Proceedings of the 30th Chinese Control Conference, 2011Co-Authors: Xudong YeAbstract:In this paper, we propose a decentralized adaptive output-feedback controller for a class of large-scale nonlinear systems with time-varying delays and unknown high-Frequency-Gain signs. We establish global asymptotic stabilization results, without using Razumikhin Theorem or constructing Lyapunov-Krasovskii functionals. The paper enlarges the class of large-scale nonlinear systems for which global decentralized adaptive output- feedback controller can be designed.
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Repetitive learning output-feedback control with unknown high-Frequency Gain sign
2011 International Conference on Electric Information and Control Engineering, 2011Co-Authors: Miao Yu, Xudong YeAbstract:An adaptive repetitive learning control method is proposed for parametric output-feedback systems doing the same work repetitively. Nussbaum-Gain technique is utilized to counteract the lack of a priori knowledge of sign of the high-Frequency Gain. A differential-difference parameter updating law which combines the time-domain and iteration-domain adaptation is introduced to facilitate the repetitive control. It is shown that the output of the system under control could converge to the desired trajectory asymptotically.
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Decentralized Adaptive Stabilization of Large-Scale Nonlinear Time-Delay Systems With Unknown High-Frequency-Gain Signs
IEEE Transactions on Automatic Control, 2011Co-Authors: Xudong YeAbstract:In this technical note, we propose a decentralized adaptive output-feedback stabilizer for a class of large-scale nonlinear time-delay systems without a priori knowledge of subsystem high-Frequency-Gain signs. The time delays can be in the outputs of subsystems and in the interconnections among subsystems. Global asymptotic stabilization results have been proved and a simulation example is given. The note enlarges the class of large-scale nonlinear systems for which global decentralized adaptive stabilizer can be designed.
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CDC - Decentralized adaptive output-feedback stabilization of large-scale time-delay nonlinear systems with unknown high-Frequency-Gain signs
Proceedings of the 48h IEEE Conference on Decision and Control (CDC) held jointly with 2009 28th Chinese Control Conference, 2009Co-Authors: Xudong YeAbstract:In this paper, we propose a decentralized adaptive output-feedback controller for a class of large-scale time-delay nonlinear systems with unknown high-Frequency-Gain signs. We establish global asymptotic stabilization results, without using Razumikhin Theorem or constructing Lyapunov-Krasovskii functionals. The paper enlarges the class of large-scale nonlinear systems for which global decentralized adaptive output- feedback controller can be designed.
R.r. Costa - One of the best experts on this subject based on the ideXlab platform.
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Multivariable adaptive control using high-Frequency Gain matrix factorization
IEEE Transactions on Automatic Control, 2004Co-Authors: A.k. Imai, R.r. Costa, P.v. KokotovicAbstract:In this note, we extend the application of a less restrictive condition about the high-Frequency Gain matrix to design stable direct model reference adaptive control for a class of multivariable plants with relative degree greater than one. The new approach is based on a control parametrization derived from a factorization of the high-Frequency Gain matrix K/sub p/ in the form of a product of three matrices, one of them being diagonal. Three possible factorizations are presented. Only the signs of the diagonal factor or, equivalently, the signs of the leading principal minors of K/sub p/, are assumed known.
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Variable structure model reference adaptive control for systems with unknown high Frequency Gain
42nd IEEE International Conference on Decision and Control (IEEE Cat. No.03CH37475), 2003Co-Authors: R.r. Costa, F. LizarraldeAbstract:In this paper, we consider the design of a variable structure model reference adaptive control (VS-MRAC) for plants with relative degree one without the knowledge of the sign of the plant high Frequency Gain. A switching method for the control signal, based on an appropriate monitoring function, is proposed. As a result, we show that after a finite number of switchings, the tracking error converges to zero at least exponentially. Interestingly enough, if the initial conditions of some states of the closed-loop system are zero, we show that at most one switching is needed.
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Multivariable MRAC using high Frequency Gain matrix factorization
Proceedings of the 40th IEEE Conference on Decision and Control (Cat. No.01CH37228), 2001Co-Authors: A.k. Imai, R.r. Costa, P.v. KokotovicAbstract:A MIMO (multiple-input, multiple-output) analog to the well-known Lyapunov-based SISO (single-input, single-output) design of MRAC (model-reference adaptive control) has been recently introduced by L. Hsu et al. (2001). The new design utilizes a control parametrization derived from a factorization of the high-Frequency Gain matrix K/sub p/=SDU, where S is symmetric positive-definite, D is diagonal and U is unity upper-triangular. Only the signs of the entries of D or, equivalently, the signs of the leading principal minors of K/sub p/, were assumed to be known. However, the result was restricted to plants with (vector) relative degree one. In this paper, we extend the MRAC for more general plants with relative degree greater than one. We present three possible factorizations of K/sub p/ and the resulting update laws.
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A solution to the MRAC design without knowledge of the sign of the high Frequency Gain
Proceedings of 1994 American Control Conference - ACC '94, 1994Co-Authors: R.r. CostaAbstract:This paper presents a solution to the problem of designing continuous-time adaptive controllers when the sign of the high Frequency Gain of the plant is not available a priori. The proposed algorithm estimates the high Frequency Gain and uses its sign in the adaptation laws of the controller parameters. It is shown that a continuous counterpart of the prediction error used in discrete-time systems plays a fundamental role in the proposed adaptive scheme. A sketch of the stability proof is proposed for the case of a first order plant where the high Frequency Gain is the only unknown parameter. Simulations illustrate the behavior of the new algorithm.
Deog-kyoon Jeong - One of the best experts on this subject based on the ideXlab platform.
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A 0.18-μm CMOS 3.5-Gb/s continuous-time adaptive cable equalizer using enhanced low-Frequency Gain control method
IEEE Journal of Solid-State Circuits, 2004Co-Authors: Jong Sang Choi, Moon Sang Hwang, Deog-kyoon JeongAbstract:This paper describes a high-speed CMOS adaptive cable equalizer using an enhanced low-Frequency Gain control method. The additional low-Frequency Gain control loop enables the use of an open-loop equalizing filter, which alleviates the speed bottleneck of the conventional adaptation method. In addition, combined adaptation of low-Frequency Gain and high-Frequency boosting improves the adaptation accuracy while supporting high-Frequency operation. The open-loop equalizing filter incorporates a merged-path topology and offers infinite input impedance, which are suitable for higher Frequency operation and cascaded design. This equalizing filter controls its common-mode output voltage level in a feedforward manner, thereby improving bandwidth. A prototype chip was fabricated in 0.18- mu;m four-metal mixed-mode CMOS technology. The realized active area is 0.48 times;0.73 mm2. The prototype adaptive equalizer operates up to 3.5 Gb/s over a 15-m RG-58 coaxial cable with 1.8-V supply and dissipates 80 mW. Moreover, the equalizing filter in manual adjustment mode operates up to 5 Gb/s over a 15-m RG-58 coaxial cable.
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A 0.18-/spl mu/m CMOS 3.5-gb/s continuous-time adaptive cable equalizer using enhanced low-Frequency Gain control method
IEEE Journal of Solid-State Circuits, 2004Co-Authors: Jong Sang Choi, Moon Sang Hwang, Deog-kyoon JeongAbstract:This paper describes a high-speed CMOS adaptive cable equalizer using an enhanced low-Frequency Gain control method. The additional low-Frequency Gain control loop enables the use of an open-loop equalizing filter, which alleviates the speed bottleneck of the conventional adaptation method. In addition, combined adaptation of low-Frequency Gain and high-Frequency boosting improves the adaptation accuracy while supporting high-Frequency operation. The open-loop equalizing filter incorporates a merged-path topology and offers infinite input impedance, which are suitable for higher Frequency operation and cascaded design. This equalizing filter controls its common-mode output voltage level in a feedforward manner, thereby improving bandwidth. A prototype chip was fabricated in 0.18-/spl mu/m four-metal mixed-mode CMOS technology. The realized active area is 0.48/spl times/0.73 mm/sup 2/. The prototype adaptive equalizer operates up to 3.5 Gb/s over a 15-m RG-58 coaxial cable with 1.8-V supply and dissipates 80 mW. Moreover, the equalizing filter in manual adjustment mode operates up to 5 Gb/s over a 15-m RG-58 coaxial cable.
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A CMOS 3.5 Gbps continuous-time adaptive cable equalizer with joint adaptation method of low-Frequency Gain and high-Frequency boosting
2003 Symposium on VLSI Circuits. Digest of Technical Papers (IEEE Cat. No.03CH37408), 2003Co-Authors: Jong Sang Choi, Moon Sang Hwang, Deog-kyoon JeongAbstract:This paper describes a high-speed CMOS adaptive cable equalizer with the joint adaptation method of low-Frequency Gain and high-Frequency boosting. The adaptation method compares not only the high-Frequency contents but also the low-Frequency contents. By this joint adaptation method, the adaptation inaccuracy due to amplitude deviation can be reduced. The filter cell in the equalizer uses the variable-capacitor tuning and feed-forward common-mode-voltage biasing technique to achieve high bandwidth. The prototype chip is fabricated in a 0.18 /spl mu/m mixed-mode CMOS process. The realized active area is 0.48 mm/spl times/0.73 mm. The filter cell operates up to 5 Gbps and the adaptive equalizer operates up to 3.5 Gbps over a 15-m RG-58 coaxial cable with a 1.8 V supply and 80 mW power dissipation.
F. Lizarralde - One of the best experts on this subject based on the ideXlab platform.
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a variable structure model reference robust control without a prior knowledge of high Frequency Gain sign
Automatica, 2008Co-Authors: Ramon R Costa, F. LizarraldeAbstract:The design of a variable structure model reference robust control without a prior knowledge of high Frequency Gain sign is presented. Based on an appropriate monitoring function, a switching scheme for some control signals is proposed. It is shown that after a finite number of switching, the tracking error converges to zero at least exponentially for plants with relative degree one or converges exponentially to a small residual set for plants with higher relative degree, and the input disturbance can be completely rejected without affecting the tracking performance.
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Variable structure model reference adaptive control for systems with unknown high Frequency Gain
42nd IEEE International Conference on Decision and Control (IEEE Cat. No.03CH37475), 2003Co-Authors: R.r. Costa, F. LizarraldeAbstract:In this paper, we consider the design of a variable structure model reference adaptive control (VS-MRAC) for plants with relative degree one without the knowledge of the sign of the plant high Frequency Gain. A switching method for the control signal, based on an appropriate monitoring function, is proposed. As a result, we show that after a finite number of switchings, the tracking error converges to zero at least exponentially. Interestingly enough, if the initial conditions of some states of the closed-loop system are zero, we show that at most one switching is needed.
Jong Sang Choi - One of the best experts on this subject based on the ideXlab platform.
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A 0.18-μm CMOS 3.5-Gb/s continuous-time adaptive cable equalizer using enhanced low-Frequency Gain control method
IEEE Journal of Solid-State Circuits, 2004Co-Authors: Jong Sang Choi, Moon Sang Hwang, Deog-kyoon JeongAbstract:This paper describes a high-speed CMOS adaptive cable equalizer using an enhanced low-Frequency Gain control method. The additional low-Frequency Gain control loop enables the use of an open-loop equalizing filter, which alleviates the speed bottleneck of the conventional adaptation method. In addition, combined adaptation of low-Frequency Gain and high-Frequency boosting improves the adaptation accuracy while supporting high-Frequency operation. The open-loop equalizing filter incorporates a merged-path topology and offers infinite input impedance, which are suitable for higher Frequency operation and cascaded design. This equalizing filter controls its common-mode output voltage level in a feedforward manner, thereby improving bandwidth. A prototype chip was fabricated in 0.18- mu;m four-metal mixed-mode CMOS technology. The realized active area is 0.48 times;0.73 mm2. The prototype adaptive equalizer operates up to 3.5 Gb/s over a 15-m RG-58 coaxial cable with 1.8-V supply and dissipates 80 mW. Moreover, the equalizing filter in manual adjustment mode operates up to 5 Gb/s over a 15-m RG-58 coaxial cable.
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A 0.18-/spl mu/m CMOS 3.5-gb/s continuous-time adaptive cable equalizer using enhanced low-Frequency Gain control method
IEEE Journal of Solid-State Circuits, 2004Co-Authors: Jong Sang Choi, Moon Sang Hwang, Deog-kyoon JeongAbstract:This paper describes a high-speed CMOS adaptive cable equalizer using an enhanced low-Frequency Gain control method. The additional low-Frequency Gain control loop enables the use of an open-loop equalizing filter, which alleviates the speed bottleneck of the conventional adaptation method. In addition, combined adaptation of low-Frequency Gain and high-Frequency boosting improves the adaptation accuracy while supporting high-Frequency operation. The open-loop equalizing filter incorporates a merged-path topology and offers infinite input impedance, which are suitable for higher Frequency operation and cascaded design. This equalizing filter controls its common-mode output voltage level in a feedforward manner, thereby improving bandwidth. A prototype chip was fabricated in 0.18-/spl mu/m four-metal mixed-mode CMOS technology. The realized active area is 0.48/spl times/0.73 mm/sup 2/. The prototype adaptive equalizer operates up to 3.5 Gb/s over a 15-m RG-58 coaxial cable with 1.8-V supply and dissipates 80 mW. Moreover, the equalizing filter in manual adjustment mode operates up to 5 Gb/s over a 15-m RG-58 coaxial cable.
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A CMOS 3.5 Gbps continuous-time adaptive cable equalizer with joint adaptation method of low-Frequency Gain and high-Frequency boosting
2003 Symposium on VLSI Circuits. Digest of Technical Papers (IEEE Cat. No.03CH37408), 2003Co-Authors: Jong Sang Choi, Moon Sang Hwang, Deog-kyoon JeongAbstract:This paper describes a high-speed CMOS adaptive cable equalizer with the joint adaptation method of low-Frequency Gain and high-Frequency boosting. The adaptation method compares not only the high-Frequency contents but also the low-Frequency contents. By this joint adaptation method, the adaptation inaccuracy due to amplitude deviation can be reduced. The filter cell in the equalizer uses the variable-capacitor tuning and feed-forward common-mode-voltage biasing technique to achieve high bandwidth. The prototype chip is fabricated in a 0.18 /spl mu/m mixed-mode CMOS process. The realized active area is 0.48 mm/spl times/0.73 mm. The filter cell operates up to 5 Gbps and the adaptive equalizer operates up to 3.5 Gbps over a 15-m RG-58 coaxial cable with a 1.8 V supply and 80 mW power dissipation.
