The Experts below are selected from a list of 19362 Experts worldwide ranked by ideXlab platform
Jing Zhou - One of the best experts on this subject based on the ideXlab platform.
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variable rate image compression method with Dead Zone quantizer
arXiv: Image and Video Processing, 2020Co-Authors: Jing Zhou, Akira Nakagawa, Keizo Kato, Sihan Wen, Kimihiko Kazui, Zhiming TanAbstract:Deep learning based image compression methods have achieved superior performance compared with transform based conventional codec. With end-to-end Rate-Distortion Optimization (RDO) in the codec, compression model is optimized with Lagrange multiplier $\lambda$. For conventional codec, signal is decorrelated with orthonmal transformation, and uniform quantizer is introduced. We propose a variable rate image compression method with Dead-Zone quantizer. Firstly, the autoencoder network is trained with RaDOGAGA \cite{radogaga} framework, which can make the latents isometric to the metric space, such as SSIM and MSE. Then the conventional Dead-Zone quantization method with arbitrary step size is used in the common trained network to provide the flexible rate control. With Dead-Zone quantizer, the experimental results show that our method performs comparably with independently optimized models within a wide range of bitrate.
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brief paper decentralized adaptive control for large scale time delay systems with Dead Zone input
Automatica, 2008Co-Authors: Jing ZhouAbstract:In this paper, a decentralized adaptive control scheme is proposed to address output tracking of a class of interconnected time-delay subsystems with the input of each loop preceded by an unknown Dead-Zone. Each local controller is designed using the backstepping technique and consists of a new robust control law and new updating laws. Unknown time-varying delays are compensated by using appropriate Lyapunov-Krasovskii functionals. Furthermore, by introducing a new smooth Dead-Zone inverse, the proposed backstepping design is able to eliminate the effects resulting from Dead-Zone nonlinearities in the input. It is shown that the proposed controller can guarantee not only stability, but also good transient performance.
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adaptive output control of nonlinear systems with uncertain Dead Zone nonlinearity
IEEE Transactions on Automatic Control, 2006Co-Authors: Jing Zhou, Ying ZhangAbstract:In this note, we present a new scheme to design adaptive controllers for uncertain systems preceded by unknown Dead-Zone nonlinearity. The control design is achieved by introducing a smooth inverse function of the Dead-Zone and using it in the controller design with backstepping technique. For the design and implementation of the controller, no knowledge is assumed on the unknown system parameters. It is shown that the proposed controller not only can guarantee stability, but also transient performance.
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Adaptive Control of Nonlinear Systems with Dead-Zone Nonlinearity
Lecture Notes in Control and Information Sciences, 1Co-Authors: Jing Zhou, Changyun WenAbstract:In this chapter, we present new adaptive schemes for uncertain nonlinear systems preceded by unknown Dead-Zone nonlinearity. Robust adaptive backstepping control algorithms are developed for state feedback tracking of a class of uncertain dynamic nonlinear systems preceded by unknown Dead-Zone nonlinearities, in the presence of bounded external disturbances. Output feedback tracking is also considered and this is achieved by introducing a new smooth inverse function of the Dead-Zone and using it in the controller design with backstepping technique. For the design and implementation of the controllers, no knowledge is assumed on the unknown system parameters and also the Dead-Zone. It is shown that the proposed controllers not only can guarantee stability, but also transient performance.
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Adaptive Control of Nonlinear Systems with Uncertain Dead-Zone Nonlinearity
Proceedings of the 44th IEEE Conference on Decision and Control, 1Co-Authors: Jing Zhou, Changyun WenAbstract:In this paper, we present a new scheme to design an adaptive controller for uncertain nonlinear systems with unknown Dead-Zone nonlinearity. The control design is achieved by introducing smooth approximate Dead-Zone model and certain well defined functions and by using backstepping technique. For the design and implementation of the controller, no knowledge is assumed on the uncertain system parameters and Dead-Zone parameters. It is shown that the proposed controller not only can guarantee global stability, but also can achieve excellent transient performance.
Luca Zaccarian - One of the best experts on this subject based on the ideXlab platform.
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Stubborn and Dead-Zone Redesign for Nonlinear Observers and Filters
IEEE Transactions on Automatic Control, 2020Co-Authors: Daniele Astolfi, Angelo Alessandri, Luca ZaccarianAbstract:We propose a redesign paradigm for stable estima-tors by introducing a saturation or a Dead-Zone nonlinearity with adaptive thresholds on the output injection term. Such nonlin-earities allow improving the sensitivity to measurement noise in different scenarios (impulsive disturbances or persistent noise such as sensor bias), while preserving the asymptotic convergence properties of the original observer. These redesigns apply to a broad class of state estimators, including linear observers, observers for input-affine systems, observers for Lipschitz systems , observers based on the circle criterion, high-gain observers, standard and extended Kalman filters. Simulation results confirm the effectiveness of both the stubborn and Dead-Zone redesigns.
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High-Gain Dead-Zone Observers for Linear and Nonlinear Plants
IEEE Control Systems Letters, 2019Co-Authors: Matteo Cocetti, Sophie Tarbouriech, Luca ZaccarianAbstract:We propose an adaptive Dead-Zone mechanism to robustify observers against high-frequency noise. The construction applies to Luenberger observers and high-gain observers for plants in strict feedback form. The Dead-Zone improves performances by trimming a portion of the output injection term and trapping the high frequency noise in the Dead band. We show that the observer gain and the adaptation parameters can be obtained by solving a linear matrix inequality, whose feasibility only requires detectability of the plant. The parameters obtained through this optimization ensure (in the absence of noise) global exponential stability of the estimation error dynamics, and input-to-state stability (ISS) from the measurement noise to the estimation error.
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On Dead-Zone observers for linear plants
2018Co-Authors: Matteo Cocetti, Sophie Tarbouriech, Luca ZaccarianAbstract:We propose a new class of Luenberger-like observers for LTI plants which are robust with respect to measurements affected by high-frequency noise. These observers have the classical Luenberger structure but the output injection term is corrected by means of an adaptive Dead-Zone. The Dead-Zone "cuts" part of the noise using the Dead-band. The Dead-Zone levels are dynamically adapted according to noise, establishing a trade-off between speed of convergence and sensitivity to noise. We show that both the observer gain and the adaptation parameters can be obtained solving a Linear Matrix Inequality (LMI), whose feasibility only requires detectability of the plant. The parameters obtained through this optimization procedure ensure Uniform Global Asymptotic Stability of the origin in the error coordinates. The effectiveness of the approach is shown by means of a numerical example.
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A kinematic observer with adaptive Dead-Zone for vehicles lateral velocity estimation
2018Co-Authors: Luca Zaccarian, Luca De Pascali, Francesco Biral, Matteo Cocetti, Sophie TarbouriechAbstract:In this paper we tailor the Dead-Zone based mechanism presented in [3] to the well-known kinematic observer for the estimation of vehicle lateral velocity. We extend the previous results on the Dead-Zone observer to linear parameter varying systems. The proposed mechanism maintains the structure of the kinematic observer but inserts an adaptive Dead-Zone at the output injection term. This Dead-Zone mechanism partially "cuts" the noise and increases the noise rejection performance allowing for the selection of a larger observer gain. We use this freedom to increase the observer gain to attenuate constant bias errors in the acceleration measurements. The proposed solution is easy to implement and requires only measurements acquired from standard on-board sensors. The adaptation parameters are selected solving a suitable Linear Matrix Inequality (LMI), and no manual tuning is required. We show the effectiveness of the proposed solution through numerical simulations.
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AMC - A kinematic observer with adaptive Dead-Zone for vehicles lateral velocity estimation
2018 IEEE 15th International Workshop on Advanced Motion Control (AMC), 2018Co-Authors: Luca De Pascali, Luca Zaccarian, Francesco Biral, Matteo Cocetti, Sophie TarbouriechAbstract:In this paper we tailor the Dead-Zone based mechanism presented in [3] to the well-known kinematic observer for the estimation of vehicle lateral velocity. We extend the previous results on the Dead-Zone observer to linear parameter varying systems. The proposed mechanism maintains the structure of the kinematic observer but inserts an adaptive Dead-Zone at the output injection term. This Dead-Zone mechanism partially "cuts" the noise and increases the noise rejection performance allowing for the selection of a larger observer gain. We use this freedom to increase the observer gain to attenuate constant bias errors in the acceleration measurements. The proposed solution is easy to implement and requires only measurements acquired from standard on-board sensors. The adaptation parameters are selected solving a suitable Linear Matrix Inequality (LMI), and no manual tuning is required. We show the effectiveness of the proposed solution through numerical simulations.
Gang Tao - One of the best experts on this subject based on the ideXlab platform.
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An adaptive Dead-Zone inverse controller for systems with sandwiched Dead-Zones
International Journal of Control, 2003Co-Authors: Avinash Vinayak Taware, Gang TaoAbstract:This paper addresses adaptive control of sandwich non-linear systems having an unknown sandwiched Dead-Zone between the linear dynamic blocks, as illustrated by a hydraulic valve system. An adaptive hybrid control scheme for control of such sandwiched Dead-Zone systems is developed. The proposed control scheme employs an inner-loop discrete-time feedback design and an outer-loop continuous-time feedback design, combined with an adaptive Dead-Zone inverse to cancel the Dead-Zone effect for improving output tracking. Stability and tracking performance of the closed-loop control system are analysed. Simulation results are used to illustrate the effectiveness of the proposed adaptive Dead-Zone inverse controller.
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An adaptive Dead-Zone inverse controller for systems with sandwiched Dead-Zones
Proceedings of the 2001 American Control Conference. (Cat. No.01CH37148), 2001Co-Authors: Avinash Vinayak Taware, Gang Tao, C. TeolisAbstract:This paper addresses adaptive control of sandwich nonlinear systems having an unknown sandwiched DeadZone between the linear dynamic blocks, as illustrated by a hydraulic valve system. An adaptive hybrid control scheme for control of such sandwiched Dead-Zone systems is developed. The proposed control scheme employs an inner-loop discrete-time feedback design and an outer-loop continuous-time feedback design, combined with an adaptive Dead-Zone inverse to cancel the Dead-Zone effect for improving output tracking. Tracking performance of the closed-loop control system is analyzed. Simulation results are used to illustrate the effectiveness of the proposed adaptive Dead-Zone inverse controller.
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Adaptive Dead-Zone compensation for output-feedback canonical systems
International Journal of Control, 1997Co-Authors: Ming Tian, Gang TaoAbstract:An adaptive output feedback Dead-Zone compensation scheme is designed for systems with an unknown Dead-Zone at the input of an n th-order smooth nonlinear dynamics in the output-feedback canonical form. The proposed adaptive controller employs an adaptive Dead-Zone inverse to cancel the Dead-Zone and uses a backstepping design for adaptive output feedback control. It has a new state observer parametrization that is needed to handle the Dead-Zone uncertainty and a new robust control law that is suitable for the parameter projection needed to implement an adaptive Dead-Zone inverse. The adaptive Dead-Zone compensation design ensures closed-loop signal boundedness and improves system tracking performance.
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Adaptive output Dead-Zone compensation
Proceedings of the 36th IEEE Conference on Decision and Control, 1Co-Authors: Ming Tian, Gang TaoAbstract:An adaptive control design is proposed for plants with an unknown Dead-Zone at the output of a known but possibly nonminimum phase linear dynamics. The proposed controller employs a Dead-Zone inverse and a pole placement control law designed with the internal model principle to cancel the Dead-Zone effect and to achieve the desired tracking performance. It results in a linearly parametrized estimation error which is crucial for obtaining an adaptive law for updating the adaptive inverse parameters. Simulation results show that our adaptive control scheme significantly improves the system performance.
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Adaptive Dead-Zone inverse for nonlinear plants
Proceedings of 35th IEEE Conference on Decision and Control, 1Co-Authors: Ming Tian, Gang Tao, Yi LingAbstract:An adaptive Dead-Zone inverse controller using a output feedback backstepping method is designed for systems with an unknown Dead-Zone at the input of a smooth nonlinear dynamics. It uses a new parametrization of a state observer and a new robust control law suitable for parameter projection needed for implementing an adaptive Dead-Zone inverse. The proposed adaptive design ensures closed-loop signal boundedness and improves system tracking performance.
C Philip L Chen - One of the best experts on this subject based on the ideXlab platform.
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a unified approach to adaptive neural control for nonlinear discrete time systems with nonlinear Dead Zone input
IEEE Transactions on Neural Networks, 2016Co-Authors: Shaocheng Tong, C Philip L ChenAbstract:In this paper, an effective adaptive control approach is constructed to stabilize a class of nonlinear discrete-time systems, which contain unknown functions, unknown Dead-Zone input, and unknown control direction. Different from linear Dead Zone, the Dead Zone, in this paper, is a kind of nonlinear Dead Zone. To overcome the noncausal problem, which leads to the control scheme infeasible, the systems can be transformed into a $m$ -step-ahead predictor. Due to nonlinear Dead-Zone appearance, the transformed predictor still contains the nonaffine function. In addition, it is assumed that the gain function of Dead-Zone input and the control direction are unknown. These conditions bring about the difficulties and the complicacy in the controller design. Thus, the implicit function theorem is applied to deal with nonaffine Dead-Zone appearance, the problem caused by the unknown control direction can be resolved through applying the discrete Nussbaum gain, and the neural networks are used to approximate the unknown function. Based on the Lyapunov theory, all the signals of the resulting closed-loop system are proved to be semiglobal uniformly ultimately bounded. Moreover, the tracking error is proved to be regulated to a small neighborhood around zero. The feasibility of the proposed approach is demonstrated by a simulation example.
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adaptive tracking control for a class of nonlinear systems with a fuzzy Dead Zone input
IEEE Transactions on Fuzzy Systems, 2015Co-Authors: Zhi Liu, Yun Zhang, Fang Wang, Xin Chen, C Philip L ChenAbstract:This paper focuses on a problem of adaptive control for a class of nonlinear strict-feedback systems with a fuzzy Dead Zone and immeasurable states. By using the adaptive backstepping technique, an adaptive fuzzy output-feedback controller is constructed. The proposed control method requires only one adaptive law for an nth-order system. Compared with the conventional deterministic Dead-Zone models in previous articles, the main advantage of this paper is that the proposed Dead-Zone model is uncertain and fuzzy. By defuzzifying for fuzzy Dead Zone ~Γ(u) and employing an integrated design, an integrated fuzzy controller is constructed. It is proved that, even though the Dead-Zone input ~Γ(u) is fuzzy, the integrated fuzzy controller can make the closed-loop system semiglobally uniformly ultimately bounded and the tracking error converge to a small neighborhood of the origin. Finally, simulation results are provided to show the effectiveness of the proposed approach.
Henry Hong - One of the best experts on this subject based on the ideXlab platform.
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robust adaptive control of a class of nonlinear systems with unknown Dead Zone
Automatica, 2004Co-Authors: Xingsong Wang, Chunyi Su, Henry HongAbstract:This paper deals with the adaptive control of a class of continuous-time nonlinear dynamic systems preceded by an unknown Dead-Zone. By using a new description of a Dead-Zone and by exploring the properties of this Dead-Zone model intuitively and mathematically, a robust adaptive control scheme is developed without constructing the Dead-Zone inverse. The new control scheme ensures global stability of the adaptive system and achieves desired tracking precision. Simulations performed on a typical nonlinear system illustrate and clarify the validity of this approach.
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model reference adaptive control of continuous time systems with an unknown input Dead Zone
IEE Proceedings - Control Theory and Applications, 2003Co-Authors: Xingsong Wang, Henry Hong, Chunyi SuAbstract:The adaptive control of continuous-time linear dynamic systems preceded by an unknown Dead-Zone in state space form is discussed. A lemma to simplify the error equation between the plant and the matching reference model is introduced which allows the development of a robust adaptive control scheme by involving the Dead-Zone inverse terms. This adaptive control law ensures global stability of the entire system and achieves the desired tracking precision even when the slopes of the Dead-Zone are unequal. Simulations performed on a typical linear system illustrate and clarify the validity of this approach.
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robust adaptive control of a class of nonlinear systems with unknown Dead Zone
Conference on Decision and Control, 2001Co-Authors: Xingsong Wang, Chunyi Su, Henry HongAbstract:This paper deals with the adaptive control of a class of continuous-time nonlinear dynamic systems preceded by an unknown Dead-Zone. By using a new description of a Dead-Zone and by exploring the properties of this Dead-Zone model intuitively and mathematically, a robust adaptive control scheme is developed without constructing the Dead-Zone inverse. The new adaptive control law ensures global stability of the adaptive system and achieves desired tracking precision. Simulations performed on a typical nonlinear system illustrate and clarify the validity of this approach.