Home  About us  Contact
 

Gain Performance (gain + performance)

Distribution by Scientific Domains
Engineering100%

Selected Abstracts

Neural network-based adaptive attitude tracking control for flexible spacecraft with unknown high-frequency gain

INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 6 2010
Qinglei Hu
Abstract Adaptive control design using neural networks (a) is investigated for attitude tracking and vibration stabilization of a flexible spacecraft, which is operated at highly nonlinear dynamic regimes. The spacecraft considered consists of a rigid body and two flexible appendages, and it is assumed that the system parameters are unknown and the truncated model of the spacecraft has finite but arbitrary dimension as well, for the purpose of design. Based on this nonlinear model, the derivation of an adaptive control law using neural networks (NNs) is treated, when the dynamics of unstructured and state-dependent nonlinear function are completely unknown. A radial basis function network that is used here for synthesizing the controller and adaptive mechanisms is derived for adjusting the parameters of the network and estimating the unknown parameters. In this derivation, the Nussbaum gain technique is also employed to relax the sign assumption for the high-frequency gain for the neural adaptive control. Moreover, systematic design procedure is developed for the synthesis of adaptive NN tracking control with L2 -gain performance. The resulting closed-loop system is proven to be globally stable by Lyapunov's theory and the effect of the external disturbances and elastic vibrations on the tracking error can be attenuated to the prescribed level by appropriately choosing the design parameters. Numerical simulations are performed to show that attitude tracking control and vibration suppression are accomplished in spite of the presence of disturbance torque/parameter uncertainty. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Performance analysis of reset control systems

INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 11 2010
W. H. T. M. Aangenent
Abstract In this paper we present a general linear matrix inequality-based analysis method to determine the performance of a SISO reset control system in both the ,2 gain and ,2 sense. In particular, we derive convex optimization problems in terms of LMIs to compute an upperbound on the ,2 gain performance and the ,2 norm, using dissipativity theory with piecewise quadratic Lyapunov functions. The results are applicable to for all LTI plants and linear-based reset controllers, thereby generalizing the available results in the literature. Furthermore, we provide simple though convincing examples to illustrate the accuracy of our proposed ,2 gain and ,2 norm calculations and show that, for an input constrained ,2 problem, reset control can outperform a linear controller designed by a common nonlinear optimization method. Copyright © 2009 John Wiley & Sons, Ltd. [source]

The design and performance analysis of integrated amplifier patch antenna

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2008
Adnan Kaya
Abstract This work presents the design of an active amplifier antenna. Active integrated antennas can be obtained with active components directly connected to the antenna structure. In this article, a novel active integrated single microstrip antenna analysis and its radiation pattern and gain performance is proposed. A high-efficiency, low noise, and high linear compact amplifier integrated with a microstrip antenna at 1.6 GHz is presented for RF front-end circuit applications. The design in this study consists of a rectangular microstrip antenna with a pair of parallel slots loaded close to the radiating edge of the patch and three meandering narrow slots embedded in the antenna surface. With the proposed design a size reduction of 34% for the 1.6- and 2.6-GHz resonant frequencies is obtained and the two frequencies have an operation frequency ratio of 1.30. In this design approach, the measured antenna impedance is transformed with matching to the load impedance for maximum efficiency. With the proposed amplifier antenna design, the antenna radiation pattern can be better than an antenna radiation pattern without matching. In addition, it has been shown that compensation significantly improves the return loss matching level. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2732,2736, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23765 [source]

Two-degree-of-freedom controller design for linear parameter-varying systems

ASIAN JOURNAL OF CONTROL, Issue 1 2008
Wei Xie
Abstract A design strategy for linear parameter-varying (LPV) systems is considered in a two-degree-of-freedom (TDOF) control framework. First, a coprime factorization for LPV systems is introduced. Second, based on the coprime factorization, a TDOF control framework of linear timeinvariant systems is extended to that of LPV systems. Good tracking performance and good disturbance rejection are achieved by a feedforward controller and a feedback controller, respectively. Furthermore, each controller design problem can be formulated in terms of a linear matrix inequality related to the L2 gain performance. Finally, a simple design example is illustrated. Copyright © 2008 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source]

An analysis of layout and temperature effects on magnetic-coupling factor, resistive-coupling factor, and power gain performances of RF transformers for RFIC applications

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2006
Yo-Sheng Lin
Abstract In this paper, we demonstrate a comprehensive analysis of the temperature effect (from ,25°C to 175°C) on the quality-factors (Q1 and Q2), magnetic-coupling factor (KIm), resistive-coupling factor (KRe), maximum available power gain (GA max), and minimum noise figure (NFmin) performances of RF bifilar and stacked transformers for RFIC applications. Excellent GA max of 0.713 and 0.806 (that is, NFmin of 1.469 and 0.937 dB) were achieved at 5 and 7 GHz, respectively, at room temperature, for a 1:1 stacked transformer mainly due to its high KIm and KRe. In addition, for the 1:1 bifilar transformer at room temperature, though its KIm and KRe are low, good GA max of 0.636 and 0.631 (that is, NFmin of 1.965 and 2.0 dB) were still achieved at 5 and 7 GHz, respectively, mainly due to its high Q1 and Q2. The present analysis is helpful for RF engineers to design temperature-insensitive ultra-low-voltage high-performance transformer-feedback low-noise-amplifiers (LNAs) and voltage-controlled-oscillators (VCOs), and other radio-frequency integrated circuits (RF-ICs) which include transformers. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1460,1466, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21732 [source]