This note addresses the design of antiwindup gains for obtaining larger regions of stability for linear systems with saturating inputs. Considering that a linear dynamic output feedback has been designed to stabilize the linear system (without saturation), a method is proposed for designing an antiwindup gain that maximizes an estimate of the basin of attraction of the closed-loop system. It is shown that the closed-loop system obtained from the controller plus the antiwindup gain can be modeled by a linear system with a deadzone nonlinearity. A modified sector condition is then used to obtain stability conditions based on quadratic Lyapunov functions. Differently from previous works these conditions are directly in linear matrix inequality form. Some numerical examples illustrate the effectiveness of the proposed design technique when compared with the previous ones.

/pdf/antiwindup-design-with-guaranteed-regions-of-stability-an-4y64g969il.pdf

Antiwindup design with guaranteed regions of stability: an LMI-based approach

The anti-windup technique which can be used to tackle the problems of stability and performance degradation for linear systems with saturated inputs is dealt with. The anti-windup techniques which can be found in the literature today have evolved from many sources and, even now, are diverse and somewhat disconnected from one another. In this survey, an overview of many recent anti-windup techniques is provided and their connections with each other are stated. The anti-windup technique is also explained within the context of its historical emergence and the likely future directions of the field are speculated. The focus is on so-called ‘modern’ anti-windup techniques which began to emerge during the end of the 20th century and which allow a priori guarantees on stability to be made. The survey attempts to provide constructive LMI conditions for the synthesis of anti-windup compensators in both global and local contexts. Finally, some interesting extensions and open problems are discussed, such as nested saturations, the presence of time delays in the state or the input, and anti-windup for non-linear systems.

/pdf/anti-windup-design-an-overview-of-some-recent-advances-and-3c6opbb7h1.pdf

Anti-windup design: an overview of some recent advances and open problems

This paper considers closed-loop quadratic stability and L/sub 2/ performance properties of linear control systems subject to input saturation. More specifically, these properties are examined within the context of the popular linear antiwindup augmentation paradigm. Linear antiwindup augmentation refers to designing a linear filter to augment a linear control system subject to a local specification, called the "unconstrained closed-loop behavior." Building on known results on H/sub /spl infin// and LPV synthesis, the fixed order linear antiwindup synthesis feasibility problem is cast as a nonconvex matrix optimization problem, which has an attractive system theoretic interpretation: the lower bound on the achievable L/sub 2/ performance is the maximum of the open and unconstrained closed-loop L/sub 2/ gains. In the special cases of zero-order (static) and plant-order antiwindup compensation, the feasibility conditions become (convex) linear matrix inequalities. It is shown that, if (and only if) the plant is asymptotically stable, plant-order linear antiwindup compensation is always feasible for large enough L/sub 2/ gain and that static antiwindup compensation is feasible provided a quasi-common Lyapunov function, between the open-loop and unconstrained closed-loop, exists. Using the solutions to the matrix feasibility problems, the synthesis of the antiwindup augmentation achieving the desired level of L/sub 2/ performance is then accomplished by solving an additional LMI.

/pdf/antiwindup-for-stable-linear-systems-with-input-saturation-uupecq0026.pdf

Antiwindup for stable linear systems with input saturation: an LMI-based synthesis

From the Publisher:
As research for future fourth generation (4G) mobile communication systems is underway worldwide in major companies and academic institutions, forward-thinking professionals are striving to gain a thorough understanding of the cutting-edge technologies and design techniques that will make these systems work. This book helps readers do just that by: providing a comprehensive introduction to multicarrier techniques for 4G mobile communications with a special focus on the analytical aspects; explaining radio channel characteristics and phenomena and discussing the advantages and disadvantages of the OFDM scheme; featuring new multicarrier-related techniques, MC-CDMA, research on several 4G systems, and a look at several problems to be overcome with these systems; examining the concept and detail of the ODFM scheme and how to carry out theoretical analysis on the performance of transmission systems in radio channels; showing how ODFM has been successfully adopted as a modulation scheme in communications systems and broadcasting systems such as ADSL, wireless LANs, and DVB-T.

Multicarrier techniques for 4G mobile communications

http://robot2.disp.uniroma2.it/~zack/ftp/AWclass/MulderAuto01.pdf

Brief Multivariable anti-windup controller synthesis using linear matrix inequalities

We consider the robust control of plants with saturation nonlinearities from an input/output viewpoint. First, we present a parameterization for anti-windup control based on coprime factorizations of the controller. Second, we propose a synthesis method which exploits the freedom to choose a particular coprime factorization.

Robust control of plants with saturation nonlinearity based on coprime factor representations

This paper describes the performance of QAM (quadrature amplitude modulation) systems under impulsive noise environment. In the analysis, we employ, as a model of the impulsive noise, Middleton's (1977) model labeled class A. First, the statistical characteristics of the in-phase and quadrature components of the impulsive noise are investigated, and it is proved that, in contrast to Gaussian noise, these components are dependent especially for the impulsive noise with small impulsive indices. Next, with consideration of the dependence between the in-phase and quadrature components of the noise, the performance of QAM systems with the conventional receiver designed for Gaussian noise is analyzed. The numerical results show that the performance is much worse than that achieved under Gaussian noise. Moreover, we show the design of the maximum likelihood receiver for class A impulsive noise and the great performance improvement by this receiver is confirmed. >

Performance analysis of QAM systems under class A impulsive noise environment

Millimeter-wave (mmw) frequency bands, especially 60 GHz unlicensed band, are considered as a promising solution for gigabit short range wireless communication systems. IEEE standard 802.11ad, also known as WiGig, is standardized for the usage of the 60 GHz unlicensed band for wireless local area networks (WLANs). By using this mmw WLAN, multi-Gbps rate can be achieved to support bandwidth-intensive multimedia applications. Exhaustive search along with beamforming (BF) is usually used to overcome 60 GHz channel propagation loss and accomplish data transmissions in such mmw WLANs. Because of its short range transmission with a high susceptibility to path blocking, multiple number of mmw access points (APs) should be used to fully cover a typical target environment for future high capacity multi-Gbps WLANs. Therefore, coordination among mmw APs is highly needed to overcome packet collisions resulting from un-coordinated exhaustive search BF and to increase the total capacity of mmw WLANs. In this paper, we firstly give the current status of mmw WLANs with our developed WiGig AP prototype. Then, we highlight the great need for coordinated transmissions among mmw APs as a key enabler for future high capacity mmw WLANs. Two different types of coordinated mmw WLAN architecture are introduced. One is the distributed antenna type architecture to realize centralized coordination, while the other is an autonomous coordination with the assistance of legacy Wi-Fi signaling. Moreover, two heterogeneous network (HetNet) architectures are also introduced to efficiently extend the coordinated mmw WLANs to be used for future 5 Generation (5G) cellular networks.

Millimeter-Wave Wireless LAN and Its Extension toward 5G Heterogeneous Networks

A radio communication system converts a time domain signal into a plurality of frequency signals to be allocated onto a plurality of subcarriers to be transmitted. The radio communication system changes a method of allocating the plurality of frequency signals onto the plurality of subcarriers based on transmission power information.

Radio transmission device, control device, radio communication system, and communication method

The present invention provides a photodetector-amplifier circuit capable of eliminating an influence of noise due to stray light entering a non-selected photodetector to stably select and switch a photodetector. The photodetector-amplifier circuit of the present invention comprises photodetectors 12 and 13 . The photodetector 12 is connected via a switch 16 between an inverting input terminal of an operational amplifier 11 and GND, and is also connected via a switch 18 to a voltage source Vcc. The photodetector 13 is connected via a switch 17 to the inverting input terminal of the operational amplifier 11 and GND, and is also connected via a switch 19 to the voltage source Vcc.

Shinichi Miyamoto

Papers

Robust control of plants with saturation nonlinearity based on coprime factor representations

Performance analysis of QAM systems under class A impulsive noise environment

Millimeter-Wave Wireless LAN and Its Extension toward 5G Heterogeneous Networks

Radio transmission device, control device, radio communication system, and communication method

Photodetector-amplifier circuit and optical pickup device