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Design and Development of a Helicopter Health Management System
EE 403W - Spring 2003
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Tiger Team Members
Johannes Coetzee -
Electrical Engineering |
Project Sponsors Jon Gabrys - Boeing Inc., Philadelphia Faculty Advisors
Dr. Edward Smith - Penn State University Mr. Timothy Wheeler - Penn State University
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Executive Summary
Our team has been assigned the task of developing a system that can predict life expectancies of critical structures in RC helicopters. Our design is a proof-of-concept experiment with future applications on full-scale helicopters. A market pull has indicated the need for a real-time data acquisition system that can capture tri-axial acceleration and the strain corresponding with various maneuvers. The structures we were interested in collecting strain measurements from were the tele-boom and horizontal tail fin. With the data we received, one can determine the relationship between strain and acceleration. The hope of the helicopter industry is to reduce dependency on strain gages, and determine structural life expectancy simply from acceleration data.
Our design was centered on acquiring five streams of data. These were x-axis acceleration, y-axis acceleration, z-axis acceleration, tele-boom strain, and tail fin strain. Our goal was to measure, signal condition, transmit, receive, and acquire this data on a ground station laptop. This process was completed real-time so that data could be analyzed, and if need be tests re-run to create the best data samples. This capability distinguishes our contribution from previous studies done on this helicopter. The system we designed had five components.
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1. Measurement
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Mounting of strain gages on - Placement of Crossbow IMU (inertial measurement unit) in
helicopter payload for 2. Signal Conditioning - Adjustable Wheatstone bridge circuitry. - Signal amplification circuitry. - Signal level shifting circuitry. 3. Transmission - Wireless analog data transmission using two Crossbow WSC-100 4-channel transmitters.
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4. Reception
- Data reception using two Crossbow WSC-100 4-channel receivers. 5. Data Acquisition - Data acquisition using a National Instruments DAQCard-700 and a 5-channel data display and storage program written in Labview code.
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Results
On April 26, 2003 a flight test was performed and the above system's capabilities were demonstrated. We successfully acquired strain and acceleration data. The most convincing proof of our system performance is the data representing z-axis acceleration and tail fin strain. The following graphs are the results of a loop maneuver performed by our RC helicopter pilot Brian Reed. By correlating the acquired acceleration to the acquired strain reading we are able to predict future strain while only measuring acceleration.
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