Active vibration H∞ control of offshore steel jacket platforms using delayed feedback

• Published in: Journal of sound and vibration 2013-10, Vol.332 (22), p.5662-5677
• Main Authors: Zhang, Bao-Lin, Tang, Gong-You
• Format: Article
• Language: English
• ISSN: 0022-460X; 1095-8568
• DOI: 10.1016/j.jsv.2013.06.029

This paper is concerned with delayed H∞ control for an offshore steel jacket platforms subject to external wave force. By artificially introducing a proper time-delay into control channel, a delayed H∞ controller is designed to attenuate the wave-induced vibration of the offshore platform and thereby improve the control performance of the system. The problem of the controller design is transformed into a nonlinear minimization problem. It is shown through simulation results that compared with the delay-free H∞ control scheme, the vibration amplitudes of the offshore steel jacket platform with the delayed H∞ control scheme are in the same level as the ones with the delay-free H∞ control scheme, while the required control force by the delayed H∞ control scheme is much smaller than that by the delay-free H∞ control scheme. Compared with the feedforward and feedback optimal control scheme, both the vibration amplitudes of the offshore platform and the required control force with the delayed H∞ control scheme are smaller than the ones with the feedforward and feedback optimal control scheme.