Dynamic Positioning during Heavy Lift Operations Using fuzzy control techniques, Nonlinear Observer and H-Infinity Method Separately to Obtain Stable DP Systems for Heavy Lift Operations J. Ye Thesis for the degree of MSc in Marine Technology in the specialization of DPO – Marine Engineering Dynamic Positioning during Heavy Lift Operations By Jun Ye Performed at RH Marine This thesis (SDPO.16.007.m.) is classified as confidential in accordance with the general conditions for projects performed by the TUDelft. 31.03.2016 Company supervisor Responsible supervisor: E. El Amam Daily Supervisor(s): E. El Amam E-mail: [email protected] Thesis exam committee Chair/Responsible Professor: Prof. ir. J.J. Hopman Staff Member: Dr M. Godjevac Staff Member: Dr. R.R. Negenborn Company Member: E. El Amam Author Details Studynumber: 4274830 Author contact e-mail: [email protected] Summary Dynamic positioning has been developed for over half a century and is now widely used on board. However, the existing dynamic positioning system is not specially made with heavy lift vessels. This report is to solve the dynamic positioning problem during heavy lift operations. To fulfill this goal, the robustness and stability of the solutions are also considered. The solutions mentioned in this report are based on the RH Marine vessel model and the RH Marine dynamic positioning system. First the crane vessel model is reviewed and checked. Then the solutions are chosen and applied. At last the results are presented and analyzed. The stability of each solution is approached and the robustness of each solution is tested in Simulink. There are three solutions in this thesis. Fuzzy controller, nonlinear passive observer and H-infinity controller are implemented to the original system separately. For first two solutions, there’s no theoretical proof that they are robust. For H-infinity controller, it is proven to be robust. All three solutions showed good robustness under tests. This report, as a master thesis, is to present the dynamic positioning problem to the reader and to provide possible solutions to the heavy lift dynamic positioning problem. i Table of Content Summary .................................................................................................................................................. i 1 Introduction ..................................................................................................................................... 1 Crane Vessels ....................................................................................................................... 1 Offshore Heavy Lifting ........................................................................................................ 2 Dynamic Positioning ............................................................................................................ 4 Structure of the Thesis ......................................................................................................... 6 2 Problem of Dynamic Positioning during Heavy Lift Operations and Current Solutions ................ 6 Problem of Dynamic Positioning during Heavy Lift Operations......................................... 7 Current Solutions ............................................................................................................... 10 2.2.1 Current Solutions in Practice .................................................................................. 10 2.2.2 Current Solution in Theory ..................................................................................... 12 Conclusion ......................................................................................................................... 12 3 Modelling of the Vessel and Simulation of the Problem .............................................................. 13 Simulation Model .............................................................................................................. 13 3.1.1 Reference Frames ................................................................................................... 13 3.1.2 Low Frequency Vessel Model ................................................................................ 14 Simulation of the Heavy Lift Mooring Problem ................................................................ 15 3.2.1 Under Seastate 0 ..................................................................................................... 16 3.2.2 Under Seastate 3 ..................................................................................................... 18 3.2.3 With Setpoint Changed ........................................................................................... 19 Conclusion ......................................................................................................................... 21 4 Possible Solutions and Candidate Solutions ................................................................................. 21 Possible Solutions .............................................................................................................. 21 4.1.1 Improve the Observer ............................................................................................. 22 4.1.2 Improve the controller ............................................................................................ 27 4.1.3 Other Solutions ....................................................................................................... 30 Candidate Solutions ........................................................................................................... 32 4.2.1 Load estimator with a fuzzy controller ................................................................... 32 4.2.2 Nonlinear passive observer ..................................................................................... 33 4.2.3 H-infinity controller ................................................................................................ 33 ii 4.2.4 Auxiliary solution: AGC ........................................................................................ 33 Conclusion ......................................................................................................................... 33 5 Implementation of Candidate Solutions ........................................................................................ 34 Fuzzy PID Controller ......................................................................................................... 34 5.1.1 Calculations of mooring stiffness ........................................................................... 34 5.1.2 Load estimator ........................................................................................................ 37 5.1.3 The fuzzy logic ....................................................................................................... 39 5.1.4 Pole Placement Design ........................................................................................... 41 5.1.5 Fuzzy logic ............................................................................................................. 43 Nonlinear Passive Observer ............................................................................................... 45 5.2.1 Observer Model ...................................................................................................... 45 5.2.2 The Tuning of the Nonlinear Passive Observer ...................................................... 46 H-infinity Control Method ................................................................................................. 48 5.3.1 H-infinity Control Method ..................................................................................... 48 5.3.2 H-infinity for crane vessels..................................................................................... 49 5.3.3 Implementation of H-infinity controller ................................................................. 50 6 Results of Implemented Candidate Solutions ............................................................................... 50 Results of the Fuzzy PID Controller .................................................................................. 51 6.1.1 Under Seastate 0 ..................................................................................................... 51 6.1.2 Under Seastate 3 ..................................................................................................... 54 6.1.3 Analyze of the results ............................................................................................. 56 Performance of the Observer ............................................................................................. 56 6.2.1 Performance of Nonlinear Passive Observer in Simulation ................................... 56 6.2.2 Comparing Experiment .......................................................................................... 63 6.2.3 Conclusion of Nonlinear Passive Observer ............................................................ 71 Performance of H-infinity Controller ................................................................................ 71 6.3.1 Under Seastate 0 ..................................................................................................... 71 6.3.2 Under Seastate 3 ..................................................................................................... 73 6.3.3 Analyze of H-infinity Controller ............................................................................ 74 Comparison