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Paper Seminar


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A Bottom-Following Preview Controller for Autonomous Underwater Vehicle

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Paper Seminar

  1. 1. A Bottom-Following Preview Controller for Autonomous Underwater Vehicles Carlos Silvestre, Rita Cunha, Nuno Paulino, and António Pascoal By: Ahmed El SheikhMSc Student, Mechatronics and Robotics, Sghool of Innovative Design, E-JUST
  2. 2. Carlos Silvestre: PhD, (IST), Lisbon,Portugal.Rita Cunha: PhD, (IST), Lisbon,Portugal.Nuno Paulino: M.Sc, (IST),Lisbon, Portugal. António M. Pascoal, PhD, (IST), Lisbon, Portugal
  3. 3. Overview• State of The Art• Vehicle Dynamics• Error Space• Preview Problem Formulation• Discrete Time Controller Design• Reference Path• Implementation• Simulation Results
  4. 4. State of The Art• Solving the problem of bottom –following for AUV• Using the echo sounders to evaluate the terrain characteristics• AUV linearized error dynamics for a pre-de ned set of operating regions• Using the LMIs to solve the H2 state feedback control problem• Using the D-Methodology to implement non-linear controller.
  5. 5. Vehicle Dynamics INFANTE vehicle Vehicle CharacteristicsLength(m) 4.5Width(m) 1.1Height(m) 0.6Thrusters 2 (Propellers & Nozzles)
  6. 6. Vehicle Dynamics(cont’) Coordinate frames: inertial {I}, Body {B} Serret {T}, Desired Body {C}
  7. 7. Error SpaceThe vector of control inputs is:And the output vector is:Assume straight line, Vr=qc=0,
  8. 8. Error Space(cont’)Error linearizationDiscretization
  9. 9. Preview Problem Formulation Two echo sounders are used to Reference path—slope discontinuity measure the characteristics of the seabed ahead of the AUV. The seabed signalThe linear error dynamics
  10. 10. Preview Problem Formulation(cont’)
  11. 11. Discrete Time Controller DesignThe Linear Matrix Inequalities Theoretical Background(LMIs)approach is used todesign the discrete time H2 Feedback interconnectionstate feedback controller
  12. 12. Discrete Time Controller Design(cont’)Preview Controller Synthesis Technique
  13. 13. Reference Path Sensor readings &offset to obtain the data points•Adding the elevation offset•Output inertial frame {I} - x coordinate•Points- straight linesFinal computed path (segments of straight lines)
  14. 14. ImplementationAffine Parameter-Dependent Description of Operating regions parameterized byThe plant
  15. 15. Implementation (cont’) Implementation setup using gain scheduling and the D-methodology D- Methodology•Integrators (input)•Differentiator (needed•Stability Characteristics•Linearization•Auto trimming Property
  16. 16. Implementation (cont’) Evolution of the preview gains f(t)Closed-loop system’s H2 norm Trajectories described by the vehicle
  17. 17. Simulation ResultsThe control objective is to achieve a constant 15-mbottom elevation offset. Descending phase Climbing phase. Error vector Xe (t)
  18. 18. The Papers I’ve presented The PapersPaper 1 A SURVEY OF UNDERWATER VEHICLE NAVIGATION: RECENT ADVANCES AND NEW CHALLENGESPublishedPaper 2 An Adaptive Controller for Underwater Vehicle-Manipulator Systems Including Thruster DynamicsPublished Proceedings of the 2010 International Conference on Modeling, Identification and Control, Okayama, Japan, July 17-19,2010Paper 3 A Bottom-Following Preview Controller for Autonomous Underwater VehiclesPublished IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY, VOL. 17, NO. 2, MARCH 2009
  19. 19. Any Questions