ACTIVE AND SEMI-ACTIVE CONTROL METHODS IN WAVE-STRUCTURE INTERACTION

There are a variety of proposed passive, active, and semi-active motion reduction systems for floating platforms. All these methods can be classified according to the energy requirements, the energy absorption, and the energy storages. The theoretical and experimental results for a semi-active method with open bottom chambers and air valves is presented. Even a quite coarse model leads to a fourth order bilinear equation system to which the classical design methods for linear controllers cannot be applied. The numerically computed optimal trajectories can be used as a reference, but because of the computing time, they are still away from real-time applications. A control law determined by minimizing the time derivative of the Lyapunov function yields a very poor system behaviour. A heuristic control which is much more efficient is proposed and investigated. This control law is based on the physical insight and can be expressed by the very simple equations. For the levelling of initial states a comparison with the optimal trajectories and the optimal control signals is carried out. The performance index with the heuristic control law is 150% of the optimal index which is quite low compared with 420% for the Lyapunov type controller.

  • Supplemental Notes:
    • OMAE 1995, 14th Intl Conf on Offshore Mechanics & Arctic Engng; 18-22 June 1995; Copenhagen, Denmark. Sponsored by ASME et al. Procs. Publ by ASME, ISBN 0-7918-1306-1. Vol I, Pt A, p 377 [6 p, 17 ref]
  • Authors:
    • Ehler, J
  • Publication Date: 1995

Language

  • English

Subject/Index Terms

Filing Info

  • Accession Number: 00718271
  • Record Type: Publication
  • Source Agency: British Maritime Technology
  • Files: TRIS
  • Created Date: Mar 27 1996 12:00AM