Michael W. Corbett, Peter T. Lamm, U.S. Air Force Research Laboratory; T. Baudendistel, J. Mitch Wolff, E. A. Walters, PC Krause and Associates, Inc. Aircraft power demands continue to increase with the increase in electrical subsystems. These subsystems directly affect the behavior of the power and propulsion subsystems and this interdependency can no longer be neglected in system analyses and prognostic health management (PHM) schemes. The performance of the whole aircraft must be considered with the combined interactions between the power, propulsion, and aeronautical subsystems. The larger loading demands placed on the power and propulsion subsystems result in thrust, speed, and altitude transients that affect the whole aircraft and result in different operating parameters. The complex models designed to integrate new capabilities have a high computational cost. This paper investigates the possibility of using a hardware-in-the-loop (HIL) analysis with real time integration of the aircraft/propulsion system and its possible application to PHM schemes. Using this method, a significant reduction in computational runtime is observed, and the airframe/turbine engine model is usable in an observer based PHM system. This would allow for a more complete analysis of the interactions between engine loading and aircraft performance by passing some real hardware component data to a real-time health observer. The possible implementation of a real-time, observer based PHM system is also discussed. 2007 ISHM Conference, August 2007. Contact information:...
Read MoreNoninvasive Approach to Health Management of Aircraft Power Systems Using Torque Ripple
T. Baudendistel, PC Krause and Associates, inc; S. Pekarek, Purdue University; Steve Peecher, GE Aerospace; Sean Field, Nathan Kumbar, Naval Air Systems Command; E. A. Walters, PC Krause and Associates, inc. In this presentation, a recently developed hardware and software tool for the health management of electric generators, motors, power electronic components, and electric power systems will be presented. This tool enables higher fidelity health management prognostics. The hardware component of this tool is a vibration sensor that is low cost, durable, and relatively straightforward to implement in a drive system or power electronic module. The sensor has been used to detect torque-ripple-induced vibration created by electric machines. It provides a convenient means to detect faults of both electrical and mechanical components of electric drive systems and also facilitates feedback-based control to mitigate the vibration source through control of the excitation to a machine. The first software tool analyzes the raw data acquired by the vibration sensor. This software utilizes both signal processing and statistical algorithms to reduce the acquired data into a user friendly pareto chart format. This format allows vehicle level PHM systems to cost-effectively analyze and store pertinent data relating to the health of the power system. This format also allows ground maintenance teams to quickly assess the health changes between flights without adding to “information overload”. The second software tool is a method of Distributed Heterogeneous Simulation (DHS) that provides a means to simulate the healthy and faulted behavior of large-scale systems at a speed and level of detail heretofore unachievable. Specifically, DHS enables the synchronized interconnection of any number of dynamic subsystem simulations, developed using any combination of a variety of programs/languages, and implemented on a single computer/workstation/supercomputer, a local area network (Intranet), a distributed, and any combination thereof. Theoretically, using an -computer network, DHS can approach an gain in computational speed over single computer, single numerical algorithm implementation. It is shown that through coupling of these tools, a comprehensive prognostics and health management system (PHM) for aircraft generators and associated electrical systems can be developed. Specifically, using DHS, component and system-level simulations of aircraft generator systems under nominal and failure modes can be performed efficiently. Using the simulation results obtained, the vibration sensor, unique monitoring concepts and advanced signal conditioning are coupled to establish an approach that can effectively detect component degradation and predict time-to-failure, and to develop feedback-based strategies for operation of generator electrical systems under component degradation or failure. Hence, maintaining the war fighting capabilities by extending the life of the aircraft electrical systems. Contact information:...
Read MoreEvaluating Real-Time Platforms for Aircraft Prognostic Health Management Using Hardware-in-the-Loop
Michael Boyd, Mitch Wolff, T. Baudendistel, PC Krause and Associates, Inc; Michael Corbett, Peter Lamm, U.S. Air Force Research Laboratory Aircraft power demands continue to increase with the increase in electrical subsystems. These subsystems directly affect the behavior of the power and propulsion systems and can no longer be neglected or assumed linear in system analyses and prognostic health management (PHM) schemes. The complex models designed to integrate new capabilities have a high computational cost. Hardware-in-the-loop (HIL) is being used to investigate aircraft power systems by using a combination of hardware and simulations. This paper considers two different real-time simulators in the same HIL configuration. A representative electrical power system is removed from a turbine engine simulation and is replaced with the appropriate hardware attached to a 350 horsepower drive stand. Variables are passed between the hardware and the simulation in real-time to update model parameters and to synchronize the hardware with the model. Real-time simulation platforms from dSPACE, National Instruments (NI), and MathWorks’ xPC are utilized for this investigation. Similar results are obtained when using HIL and a simulated load. Initially, noticeable differences are seen when comparing the results from each real-time operating system. However, discrepancies in test results obtained from the NI system can be resolved. This paper briefly details the underlying problem and its solution before discussing test results which show that dSPACE, NI, and xPC can be configured to match the baseline Simulink data and can be utilized in an observer based PHM system. The possible implementation of a real-time, observer based PHM system is also discussed. GDIT Integrated Systems Health Management (ISHM) Conference, August 2008. Contact information:...
Read MoreLow-Cost/High-Speed Bearing Tester Using Torque Ripple Sensors
T. Baudendistel, PC Krause and Associates, Inc; S. Pekarek, Purdue University; E. A. Walters, PC Krause and Associates, Inc. In the aviation industry, the ever increasing need for more power in addition to the need to reduce weight and size has driven the requirements for higher and higher rotating speeds in aircraft machinery. This in turn has put an increasing burden on the bearings used in these machines. In this presentation, a recently developed fixture was developed to test high-speed bearings in the range of 25,000 rpm. This low-cost test fixture was developed to test bearings to failure by applying an artificial axial load. This low-cost/high-speed bearing tester is instrumented with a low cost torque ripple sensors and temperature probes to aid in the development of a PHM algorithm as well as a suite of temperature probes to monitor bearing temperatures. As the bearings fail the torque ripple and temperature signatures created are recorded for future analysis. Due to the low-cost nature of the fixture, it will also include an accelerometer dedicated to determining the speed of the rotating drive motor. Contact information:...
Read MoreSimulation of an F-18 Cycloconverter and Transformer-Rectifier Load Using an Automated State Modeler
S. D. Pekarek, O. Wasynczuk, T. Skvarenina, E. A. Walters, PC Krause and Associates, Inc. 33rd Intersociety Energy Conversion Engineering Conference Proceedings, August 1998.
Read MoreAn Automated State Model Generation Algorithm for Simulation/Analysis of Power Systems with Power Electronic Components
S. D. Pekarek, E. A. Walters, T. L. Skvarenina, O. Wasynczuk, PC Krause and Associates, Inc. In this paper, a recently developed algorithmic method of deriving the state equations of power systems containing power electronic components is described. Therein the system is described by the pertinent branch parameters and the circuit topology; however, unlike circuit-based algorithms, the difference equations are not implemented at the branch level. Instead, the composite system state equations are established. A demonstration of the computer implementation of this algorithm to model a variable-speed, constant-frequency aircraft generation system is described. Because of the large number of states and complexity of the system, particular attention is placed on the development of a model structure which provides optimal simulation efficiency. SAE Transactions Journal of Aerospace, sec. 1, vol. 107, Month 1998, pp....
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