| |  | Cao, C. | Novel <formula formulatype="inline"><tex>${cal L}_{1}$</tex></formula> Neural Network Adaptive Control Architecture With Guaranteed Transient Performance read moreAbstract: In this paper, we present a novel neural network (NN) adaptive control architecture with guaranteed transient performance. With this new architecture, both input and output signals of an uncertain nonlinear system follow a desired linear system during the transient phase, in addition to stable tracking. This new architecture uses a low-pass filter in the feedback loop, which consequently enables to enforce the desired transient performance by increasing the adaptation gain. For the guaranteed transient performance of both input and output signals of the uncertain nonlinear system, the ${cal L}_{1}$ gain of a cascaded system, comprised of the low-pass filter and the closed-loop desired reference model, is required to be less than the inverse of the Lipschitz constant of the unknown nonlinearities in the system. The tools from this paper can be used to develop a theoretically justified verification and validation framework for NN adaptive controllers. Simulation results illustrate the theoretical findings.  This article is not yet tagged | 2007 |
| | | Cao, C. | Intelligent Excitation for Adaptive Control With Unknown Parameters in Reference Input read moreAbstract: Model reference adaptive control problem is considered for a class of reference inputs dependent upon the unknown parameters of the system. Due to the uncertainty in the reference input, the tracking objective cannot be achieved without parameter convergence. The common approach of injecting persistent excitation (PE) in the reference input leads to tracking of the excited reference input as opposed to the true one. A new technique, named intelligent excitation, is presented for introducing an excitation signal in the reference input and regulating its amplitude, dependent upon the convergence of the output tracking and parameter errors. Intelligent excitation ensures parameter convergence, similar to conventional PE; it vanishes as the errors converge to zero and reinitiates with every change in the unknown parameters. As a result, the regulated output tracks the desired reference input and not the excited one. This article is not yet tagged | 2007 |
| | | Bashrullah, R. | RF subsystems implemented in mainstream CMOS - Overcoming special concerns affecting performance and cost read moreAbstract: Research is underway to explore the feasibility of implementing complete RF subsystems in standard mainstream CMOS processes without a need for any off-chip components. Progress to date has verified that RF circuits and on-chip antennas adequate for chip to chip communication can be realized, and it can be stated with some certainty that feasibility has been established. Radio architecture, signaling methodology, and individual circuit blocks have been devised and confirmed. It remains to demonstrate an on-chip reference with +/-150 ppm stability, optimize the individual circuit blocks, and demonstrate the overall concept in a single integrated chip This article is not yet tagged | 2006 |
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