Project Kontakt II LH12066 – Spectral methods for vibration suppression and control design of mechanical systems with feedback delays

Supported by the Ministry of Education of Czech Republic

Brief description

A complete methodology for synthesis of active system vibration suppression using delay resonators followed by control synthesis of the damped systems with communication delays in the feedback loop will be proposed. As the first objective, the research on delay resonator design achieved by the University of Connecticut will be extended. Applying the modern spectral methods, a comprehensive analysis of the dynamics and robust synthesis of algorithms for vibration suppression of systems damped by several delay resonators will be performed. Consequently, the algorithms for robust control of these actively damped systems will be designed. Next to the delays in the resonators, communication delays in feedback loops will be considered in the synthesis. Finally, laboratory validation of the theoretical results will be performed. The validation will be done using laboratory equipment of all the partners. Next, a laboratory system will be designed and built for the testing purposes.


  • Prof. Nejat Olgac,
    ALARM lab, Department of Mechanical Engineering, University of Connecticut
    Personal Web Page
  • Prof. Rifat Sipahi,
    Department of Mechanical and Industrial Engineering, Northeastern University
    Personal Web Page


  • QPmR algorithm update



[1j] T. Vyhlidal, V. Kucera, M. Hromcik. Signal shaper with a distributed delay: Spectral analysis and design, Automatica, Vol 49, Issue 11, November 2013, pp 3484-3489

[2j] VYHLÍDAL, T., OLGAC, N., and KUČERA, V. Delayed resonator with acceleration feedback – Complete stability analysis by spectral methods and vibration absorber design. Journal of Sound and Vibration. 2014, 333(25), pp. 6781-6795. ISSN 0022-460X

[3j] PILBAUER, D., VYHLÍDAL, T., OLGAC, N.,  Delayed Resonator With Distributed Delay in Acceleration Feedback—Design and Experimental Verification, IEEE/ASME TRANSACTIONS ON MECHATRONICS, VOL. 21, NO. 4, AUGUST 2016


[1c] T. Vyhlidal, V. Kucera, M. Hromcik. Input shapers with uniformly distributed delays. 10th IFAC Workshop in Time Delay Systems, Boston, June 22-44, 2012.

[2c] T. Vyhlidal, Olgac N. , V. Kucera, Design and Stability Analysis of Delayed Resonator with Acceleration Feedback, ASME – DSCC 2013, Standford University, Palo Alto Ca, October 21-23, 2013

[3c] Sipahi, R., Kucera, V., and Vyhlidal, T. Stability Analysis and Control Design of a Vibration Control System with Uncertain and Tunable Delays. In: Proceedings of the 12th IFAC Workshop on Time Delay Systems. Ann Arbor, MI, 28.06.2015 – 30.06.2015. New York: IFAC. 2015, pp. 123-128. IFAC-PapersOnLine. ISSN 1474-6670.

Book chapters

[1b]  VYHLÍDAL, T. and ZÍTEK, P. QPmR – Quasi-Polynomial Root-Finder: Algorithm Update and Examples [online]. In: SIPAHI, R., VYHLÍDAL, T., and LAFAY, J-F., eds. Delay Systems: From Theory to Numerics and Applications. 10th IFAC Workshop on Time Delay Systems. Boston, MA, 22.06.2012 – 24.06.2012. New York: Springer. 2014, pp. 299-312. Advances in Delays and Dynamics. ISSN 2197-117X. ISBN 978-3-319-01694-8.


Following the delayed resonator concept proposed by Prof. Olgac and his colleagues, and utilizing the resonator design as described in [2c], the delayed resonator with an acceleration feedback has been implemented using two magnetic shakers. The objective is to suppress the vibration of the cart induced by the magnetic shaker. It is done by the absorber with the second magnetic shaker actively controlled by the delayed acceleration feedback. The following videos the first experimental results.

The objective is to suppress the vibrations of the cart induced by the periodic forces emitted by the thicker voicecoil. It is done by the actively controlled absober, which is implemented using the thinner (but longer) voicecoil positioned on the cart. The absorber voicecoil is controlled by delayed acceleration feedback. If the absorber is on, the cart stops moving.

In this experiment, the scheme is supplemented by the delay based signal shapers which compensate the natural oscillatory modes of the cart (connected to the platform by two springs) and absorber (connected to the cart by two springs). Various combinations of absorber control and signal shaping being on and off are considered. If both the delay based control means are on, no oscillations should be observed on the cart.

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