Reconfigurable Control Strategies: Towards Fault – Tolerant and High – Confidence Systems

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Reconfigurable Control Strategies: Towards Fault – Tolerant and High – Confidence Systems. George Vachtsevanos Georgia Institute of Technology Atlanta GA 30332-0250 SWAN ’06 The University of Texas at Arlington. December 7 – 9, 2006. Flight Results – Bob Up. Collective Failure Scenario. - PowerPoint PPT Presentation

Text of Reconfigurable Control Strategies: Towards Fault – Tolerant and High – Confidence Systems

  • Reconfigurable Control Strategies: Towards Fault Tolerant and High Confidence SystemsGeorge VachtsevanosGeorgia Institute of TechnologyAtlanta GA 30332-0250

    SWAN 06The University of Texas at ArlingtonDecember 7 9, 2006

  • Flight Results Bob Up

  • Collective Failure Scenario

  • The ProblemImproving UAV reliability is the single most immediate and long reaching need to ensure their success. - OSD UAV Roadmap 2002-2027Unmanned aerial vehicles require a fault-tolerant control (FTC) architecture that allows them to generate and track safe flight paths before and after the occurrence of a fault.

  • The Anatomy of a FailureHydraulic fluid swapped for engine oil during maintenanceMore volatile lubricant evaporates increasing frictionIGB output bearing overheatsBearing fails from excessive heat SH-60 loses tail-rotor authority SH-60 grounded for IGB servicingHydraulic Fluid Runs Red by LCdr. Patrick KennedyMech, Winter 2001

  • Aircraft Mishaps/Failure ModesRetired Marine Lt. Gen. Bernard Trainor said the issue of aging aircraft is a constant complaint of all branches of service.Atlanta Journal ConstitutionApril 27, 2002

  • Testing, Modeling, and Reasoning Architecture for Fault Diagnosis and Failure PrognosisTesting/Seeded Fault DataModelingReasoning Architecture for Diagnosis-PrognosisIntermediateGearbox (IGB)fitted with VMEP sensors to monitor components Prevent unscheduled maintenance Assist the pilot in making intelligent decisions about air-worthinessVMEP/HUMSmodules

  • The Fault Diagnosis/Prognosis Architecture

  • Space Engine Fault AccommodationBody Flap ControllersElevonControllersRudderControllersComponent Degradation andSystem Performance Model(From Task 2)Prognostic & DiagnosticAlgorithms(From Task 4)Run-TimeDemo SystemActuator CommandsActuatorPerformance DataSystem Requirements(Task 1)Model Validation(Task 3)Integrated Flight Control System Logic(From Task 5)

  • Proposed Architecture

  • Helicopter Active System RestructuringRPM control CollectiveTail rotorSwashplate actuatorsS/P Actuator AdA S/P Actuator BdBS/P Actuator CdC Tail Rotor PitchdtrActive Control:Long. Cyclicdlon Lateral CyclicdlatCollective Pitchdcoll Tail Rotor Pitchdtr

    Alternate means of restructuring employ: tandem rotors, stabilator control, individual blade control, jettisoning of storesLong. Cyclicdlon Lateral CyclicdlatCollective Pitchdcoll Tail Rotor Pitchdtr

  • Adapts the position, velocity, acceleration, and/or jerk for the assigned waypointsProvides a simple exportable model (HURT)Implies a change to the aircraft time of arrivalWith or without reconfigurable path planningMission Adaptation

  • Reconfigurable Flight ControlBaseline controllerInverted Model PDReference Model RPM sensor:Feedback Linearization:-+Plant

    Adaptive Neural Network

  • Flight Results - Stuck Collective

  • Challenges for Control EngineersRobust, reliable and timely fault diagnosis and prognosisInterface requirements to system controllersSystem design to accommodate fault isolation, system restructuring and control reconfigurationControl reconfiguration technologiesHigh Confidence Systems!

  • Intelligent Fault Diagnosis and Prognosis for Engineering Systems

    This is a summary of the demo plans for next summer.This presentation has focused on rotary-wing technologies, but many of the controllers and tools are being applied in a Boeing-led group to the F-15 and UCAV. The OCP is going to transition to UCAV as the mission management system in the next block (block 2). In the fixed-wing demo, we will control use the T-33 UCAV surrogate in formation flight, trajectory regulation, and weapons-release control scenarios.