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http://dx.doi.org/10.5302/J.ICROS.2011.17.4.289

Improving a Digital Redesign for Time-Varying Trackers  

Song, Hyun-Seok (Inha University)
Lee, Ho-Jae (Inha University)
Kim, Do-Wan (Hanbat National University)
Publication Information
Journal of Institute of Control, Robotics and Systems / v.17, no.4, 2011 , pp. 289-294 More about this Journal
Abstract
Digital redesign is yet another efficient tool to convert a pre-designed analog controller into a sampled-data one to maintain the analog closed-loop performance in the sense of state matching. A rising difficulty in developing a digital redesign technique for trackers with time-varying references is the unavailability of a closed-form discrete-time model of a system, even if it is linear time-invariant. A way to resolve this is to approximate the time-varying reference as a piecewise constant one, which deteriorates the state matching performance. Another remedy may be to decrease a sampling period, which however could numerically destabilize the optimization-based digital redesign condition. In this paper, we develop a digital redesign condition for time-varying trackers by approximating the time-varying reference through a triangular hold and by introducing delta-operated discrete-time models. It is shown that the digitally redesigned sampled-data tracker recovers the performance of the pre-designed analog tracker under a fast sampling limit. Simulation results on the formation flying of satellites convincingly show the effectiveness of the development.
Keywords
digital redesign; time-varying references; delta operator; performance recovery;
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Times Cited By KSCI : 1  (Citation Analysis)
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