Discrete feedforward and feedback optimal tracking control for offshore steel jacket platforms

• Published in: Ocean engineering Vol. 91; pp. 371 - 378
• Main Authors: Zhang, Bao-Lin, Liu, Yu-Jia, Ma, Hui, Tang, Gong-You
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 15.11.2014; Elsevier
• Subjects: Applied sciences; Building structure; Buildings. Public works; Construction (buildings and works); Control systems; Control theory; Exact sciences and technology; Feedback; Feedforward; Hydraulic constructions; Marine; Metal structure; Nonlinear vibration; Offshore engineering; Offshore platform; Offshore platforms; Offshore structure (platforms, tanks, etc.); Optimal control; Optimization; Time-delay; Tracking; Tracking control; Offshore platform; Time-delay; Tracking; Feedforward; Nonlinear vibration; Optimal control; Vibration; Wave effect; Non linear oscillation; Jacket platform; Modeling; Feedback; Production platform; Numerical simulation; Delay time; Offshore structure
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2014.09.030

This paper is concerned with discrete feedforward and feedback optimal tracking control schemes for an offshore steel jacket platform subject to irregular wave force. By discretizing a dynamic model of the offshore steel jacket platform system, a discrete feedforward and feedback optimal tracking controller is developed first to attenuate the wave-induced vibration of the offshore platform. Then, for the case of the offshore platform with control delays, a discrete feedforward and feedback optimal tracking controller with memory is presented. The controllers can be designed by solving an algebraic Riccati equation and a Stein equation, respectively. It is found through simulation results that compared with the classic state feedback optimal tracking control schemes, the proposed control schemes are more efficient in attenuating the vibration of the offshore platform. In addition, compared with the feedforward and feedback optimal control schemes, the proposed control schemes require less control cost. •Optimal tracking control with feedforward compensation scheme is developed for an offshore platform.•The existence and uniqueness of the proposed controller is derived.•The proposed scheme and the existing schemes are compared via simulation results.•Under the proposed scheme, the required control cost is much reduced.