Browsing by Subject "Adaptive control"

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    Development of Active Traffic Management Strategies for Minnesota Freeway Corridors
    (Minnesota Department of Transportation, 2015-06) Kwon, Eil; Park, Chongmyung
    In this study, the effectiveness of the I-35W variable advisory speed limit system on the improvement of the traffic flow was evaluated with the real traffic data. The analysis results indicate there was significant reduction in the average maximum deceleration and also the traffic time reliability was substantially improved during a peak hour period. Based on the assessment results, an enhanced version was developed to be able to reflect more effectively the time-variant road traffic conditions in determining the variable speed limits in real time. The coordinated adaptive metering strategy, developed in the previous phase of this research, is also enhanced and implemented in the field in this research. The field test results of the new metering system with the 100 NB corridor indicate substantial improvements in both the mainline and ramp traffic performance compared with those from the old stratified algorithm.
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    Time delay margin analysis for adaptive flight control laws.
    (2010-12) Dorobantu, Andrei
    Adaptive control algorithms have the potential to improve performance and reliability in flight control systems. Implementation of adaptive control on commercial and military aircraft requires validation and verification of the control system's robustness to modeling error and uncertainty. Currently, there is a lack of tools available to rigorously analyze the robustness of adaptive systems due to their inherently nonlinear dynamics. This thesis addresses the use of nonlinear robustness analysis for adaptive flight control systems. First, a model reference adaptive controller is derived for an aircraft short period model. It is noted that the controller is governed by polynomial dynamics. Polynomial optimization tools are then applied to the closed-loop model to assess its robustness to time delays. Time delay margins are computed for various tuning of design parameters in the adaptive law, as well as in the presence of model uncertainty.