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 More