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Understanding robust control theory via stick balancing

Leong, Yoke Peng and Doyle, John C. (2016) Understanding robust control theory via stick balancing. In: IEEE 55th Conference on Decision and Control (CDC). IEEE , Piscataway, NJ, pp. 1508-1514. ISBN 978-1-5090-1837-6.

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Robust control theory studies the effect of noise, disturbances, and other uncertainty on system performance. Despite growing recognition across science and engineering that robustness and efficiency tradeoffs dominate the evolution and design of complex systems, the use of robust control theory remains limited, partly because the mathematics involved is relatively inaccessible to nonexperts, and the important concepts have been inexplicable without a fairly rich mathematics background. This paper aims to begin changing that by presenting the most essential concepts in robust control using human stick balancing, a simple case study popular in both the sensorimotor control literature and extremely familiar to engineers. With minimal and familiar models and mathematics, we can explore the impact of unstable poles and zeros, delays, and noise, which can then be easily verified with simple experiments using a standard extensible pointer. Despite its simplicity, this case study has extremes of robustness and fragility that are initially counter-intuitive but for which simple mathematics and experiments are clear and compelling. The theory used here has been well-known for many decades, and the cart-pendulum example is a standard in undergrad controls courses, yet a careful reconsidering of both leads to striking new insights that we argue are of great pedagogical value.

Item Type:Book Section
Related URLs:
URLURL TypeDescription Paper
Leong, Yoke Peng0000-0001-8560-8856
Doyle, John C.0000-0002-1828-2486
Additional Information:© 2016 IEEE.
Subject Keywords:Delays; Poles and zeros; Robust control; Robustness; Sensitivity; Uncertainty
Record Number:CaltechAUTHORS:20170106-124748759
Persistent URL:
Official Citation:Y. P. Leong and J. C. Doyle, "Understanding robust control theory via stick balancing," 2016 IEEE 55th Conference on Decision and Control (CDC), Las Vegas, NV, USA, 2016, pp. 1508-1514. doi: 10.1109/CDC.2016.7798480 URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:73301
Deposited By: George Porter
Deposited On:06 Jan 2017 22:47
Last Modified:09 Mar 2020 13:19

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