NN-based fuzzy control for TLP systems: A case study of practical structural parameters and wave properties

Although there are many successful applications of neural networks (NNs), however, there are still some drawbacks in using neural networks (NNs) in any control scheme. In this study an NN-based model is applied for a tension leg platform (TLP) system. A linear differential inclusion (LDI) state-space representation is constructed to represent the dynamics of the NN model. Control performance is achieved by using the parallel distributed compensation (PDC) scheme to ensure the stability of TLP systems subjected to an external wave force. In terms of the stability analysis, the linear matrix inequality (LMI) conditions are derived using the Lyapunov theory to guarantee the robustness design and stability of the TLP system. A simulation example based on practical data is given to demonstrate the feasibility of the proposed fuzzy control approach. In the end, we discuss a practical application with field data on the wave properties and structural characteristics. The results indicate the efficiency and robustness of the proposed NN based approach.

The 2D numerical wave flume and boundary conditions. The incident surface wave propagates from the left and interacts with the floating platform. Most of the wave energy could be dissipated during the wave–structure interaction. Based on natural physics, when the incident wave reaches a permeable medium, part of the wave energy is reflected backward (reflected wave) and part is transferred to the medium (transmitted wave). Transmitted waves might result from dispersion of the incident waves. The incident wave energy causes structural oscillation which also causes reflected gravity waves and transmitted waves. This complex dynamic mechanism can be simplified into three sections which can then be solved by the method of separation of variables.Figure optionsDownload as PowerPoint slideHighlights
► An NN-based model is applied for a tension leg platform (TLP) system.
► A LDI state-space representation is constructed.
► Control performance is achieved by using the PDC scheme to ensure the stability of TLP systems.
► A simulation example based on practical data is given.
► The numerical experiments indicate the efficiency and robustness of the proposed NN based approach.