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Paper Seminar



A Bottom-Following Preview Controller for Autonomous Underwater Vehicle

A Bottom-Following Preview Controller for Autonomous Underwater Vehicle



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  • 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
  • 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
  • Overview• State of The Art• Vehicle Dynamics• Error Space• Preview Problem Formulation• Discrete Time Controller Design• Reference Path• Implementation• Simulation Results
  • 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.
  • Vehicle Dynamics INFANTE vehicle Vehicle CharacteristicsLength(m) 4.5Width(m) 1.1Height(m) 0.6Thrusters 2 (Propellers & Nozzles)
  • Vehicle Dynamics(cont’) Coordinate frames: inertial {I}, Body {B} Serret {T}, Desired Body {C}
  • Error SpaceThe vector of control inputs is:And the output vector is:Assume straight line, Vr=qc=0,
  • Error Space(cont’)Error linearizationDiscretization
  • 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
  • Preview Problem Formulation(cont’)
  • Discrete Time Controller DesignThe Linear Matrix Inequalities Theoretical Background(LMIs)approach is used todesign the discrete time H2 Feedback interconnectionstate feedback controller
  • Discrete Time Controller Design(cont’)Preview Controller Synthesis Technique
  • 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)
  • ImplementationAffine Parameter-Dependent Description of Operating regions parameterized byThe plant
  • Implementation (cont’) Implementation setup using gain scheduling and the D-methodology D- Methodology•Integrators (input)•Differentiator (needed•Stability Characteristics•Linearization•Auto trimming Property
  • Implementation (cont’) Evolution of the preview gains f(t)Closed-loop system’s H2 norm Trajectories described by the vehicle
  • Simulation ResultsThe control objective is to achieve a constant 15-mbottom elevation offset. Descending phase Climbing phase. Error vector Xe (t)
  • 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
  • Any Questions