Network-based H<inf>∞</inf> control for offshore steel jacket platforms

This paper is concerned with network-based H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> control for an offshore steel jacket platform subject to nonlinear wave-induced force and external disturbance. A network-based dynamic model of the offshore platform with an active tuned mass damper mechanism is presented, and a network-based H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> control scheme is presented to attenuate the vibration of the offshore platform. The effects of the network-induced delays on the H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> control for the offshore platform is investigated. Simulation results show that the proposed network-based H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> control scheme can improve the control performance of the offshore platform significantly. In addition, the control force and the oscillation amplitudes of the offshore platform under the network-based H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> controller with proper network-induced delays are smaller than the ones under the H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> controller without network settings, which means that the proper network-induced delays are of the positive effects on the H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> control of the offshore platform.