Helicopter Data Acquisition System

1. Helicopter Data Acquisition System ECE 4512 Senior Design I

2. Team Members David Paul Robert McInnis Dr. Rob King (Advisor) Aaron Hill Jason Schemmel

3. Team Responsibilities • Aaron Hill (Power) • Circuit board layout, power consumption, and package design • David Paul (Controls) • Simulink, sensor pak installation, and control circuit design • Jason Schemmel and Robert McInnis (Communications) • RF design, circuit simulation, and antenna design

4. Purpose • To implement a helicopter data acquisition system obtaining real-time data from the fuselage and a rotating blade • Data from rotating blade can only be obtained accurately with a wireless communications system

5. Motivation Pivot Hub Blade POT Strain Gauge Nonlinear stiffness spring

6. Motivation Computer simulation of baseline case, blade lead angles without Duffing stiffness spring

7. Motivation Computer simulation of baseline case, blade lead angles with Duffing stiffness spring

8. Project Abstract Strain Gauge Position Transducer Battery Pack Power Source Wheatstone Bridge Wheatstone Bridge Amplifier Signal Conditioner 2:1 Mux KEY Power Signal EM Signal Sampler/ A/D Converter Transmitter

9. Project Abstract Receiver KEY Power Signal EM Signal Data Enable Internal Sensor Package D/A Converter/ Buffer 1:2 Demux Helicopter House Power DAQ PCMCIA Laptop

10. Signal conditioning and amplification PCMCIA DAQ Card with Dell laptop Simulink using Matlab A/D conversions and multiplexing Signal encoding and decoding Components

11. Design a control circuit to synchronize MUX/DEMUX and data converters ± 3.5 mV range must be amplified and conditioned to a 0-5V range for proper sampling Batteries must be selected to provide 333 mW for a maximum time of 45 minutes Frequency selected (100-400 MHz) for a practically sized antenna Design Requirements • Control Circuit • Power • Signal Conditioning • Transmission Frequency

12. Serial bit length must be chosen for a quantized signal with at least a precision of 2mV increments Sampling frequency of 100 Hz for adequate signal accuracy Transmitting antenna must be oriented 90° with respect to receiving antenna Software calibration is required prior to session to compensate for physical inadequacies Design Requirements • Data Transmission • Sampling Rate • Antenna Polarization • Calibration

13. Model Test Stands Spectrum Analyzer Constraints Simulink Circuit Modeling Oscilloscope X Control Circuit Power X X X Transmission Frequencies X Data Transmission X X Sampling Rates X X Calibration X X Antenna Polarization X Signal Conditioning X X X Test Requirements

14. Summary Transmitting/ Receiving System Sensor Pak

15. Future Improvements • Implement transmitting on/off switch • Automated helicopter control system

16. References • M.L. Deutsch, “Ground Vibrations of Helicopters,” Journal of the Aeronautical Sciences, Vol. 15, No.5, May 1946. • R.W. Prouty, Helicopter Aerodynamics, PJS Publishers, Inc., Peoria, IL, 1985. • B.P. Lathi, ModernDigital and Analog Communication Systems, Oxford University Press, New York, New York, 1998 • C.W. Sayer, The Complete RF Technician’s Handbook, PROMPT Publications, Indianapolis, Indiana, 1998 • United Technologies [Online]. Available: http://www.utc.com/discover/index.htm [2000, September 3]. • R.W. Prouty, Helicopter Performance, Stablility, and Control, PWS Publishers, Boston, MA, 1986. • Title 47, Part 15 – Radio Frequency Devices,” Code of Regulations, Federal Communications Commission, USA, 16 April 1999. • Omega Technologies [Online]. Available: http://www.omega.com/literature/transactions/volume3/strain2.html [2000, September 6].