Anomaly Detection and Damage Mitigation in Complex Systems by Amol M Khatkhate Pennsylvania State University
Objectives Experimental Validation of Theoretical Research Anomaly detection Damage Mitigating Control Department of Defense (DoD) Applications Rotorcraft and Armored Vehicles Jet Engines in Aircraft
Test Apparatus
Design of Test Apparutus Resonating behavior Fatigue Crack Failure crack initiation crack propagation catastrophic failure Role of microscope in the experiments
Implementation of Control System Data Acquisition : Acquiring sensor data from 3 LVDT’s, 2 load cells and feeding back reference input into DAQ board Real Time Control : Establishing connection through board under RTLinux and facilitate real time control Keyboard Interfaces : Starting and stopping of system, increasing gain and frequency of input excitation, loading and removal of damage mitigating controller in realtime Image Capture By Microscope : Capturing crack image of all three specimens on the test apparatus
Control System Architecture RTLinux Kernel communicates and controls the mechanical system through DAQ board User Space Process communicate with kernel for sending commands and receiving data Fifos are mechanism to facilitate communication between kernel and user process RTLinux Kernel Mechanical System (hardware) FIFOS USER SPACE PROCESS DAQ Board Sensor Data Command FIFO
Software Implementation Real Time Plotting COMMAND FIFO DATA FIFO THREADS Keyboard Control HARDWARE (DAQ BOARD ) SERIAL PORT Microscope Initialise module Create Fifo Handler Initialize Board Command Fifo Handler Wait for commands from keyboard Write into data fifo Cleanup module Delete Fifo Handler Mechanical System USER SPACE PROCESSES KERNEL SPACE GRAPHICAL USER INTERFACE
Experimental Results & Conclusions Anomaly detected at this point Depth and # of symbols Choice of wavelet basis
Future Work Apply results from the online fatigue testing machine to study fatigue failure under flexural loading Design of control strategy so as to enhance life (damage mitigation control) without significance loss in performance Implementation of DES to switch between controllers (similar to rotorcraft application)
DoD Applications: Jet Engine Propulsion 2 similar Jet engines in a twin engine aircraft Fault/anomaly detected in the operation of this engine Data Acquisition and Real Time Control system DES ( design the control strategy based on fault detected )
DoD Applications: Rotorcraft/Aircraft Structures MODEL VISUALISED AS INTERACTION BETWEEN BEAMS AND MASSES