1. Helicopter Data Acquisition System ECE 4512 Senior Design I

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

3. Team Responsibilities Aaron Hill (Power) Battery selection and power consumption simulation David Paul (Controls) Control circuit design and simulation Jason Schemmel (Communications) Antenna simulation and transmitter/receiver simulation Robert McInnis (Communications) Robert McInnis (Communications) Signal conditioning, sampling, and data conversion

4. Motivation Utilizes all aspects of Electrical Engineering Utilizes all aspects of Electrical Engineering High Level of Difficulty Can be used in many other applications Improvement of existing techniques Improvement of existing techniques

5. Problem Statement To develop a more efficient data acquisition system obtaining real-time data from a high speed rotating blade by replacing the use of slip-rings

6. Design Requirements Control Circuit Power Signal Conditioning Transmission Frequency Design a control circuit to synchronize MUX/DEMUX and data converters Batteries must be selected to provide 500 mW for a typical flight time of 60 minutes ± 15 mV range must be amplified and conditioned to a 0-10V range for proper sampling Frequency selected (300-500 MHz) for a practically sized antenna

7. Design Requirements Data Transmission Sampling Rate Antenna Polarization Calibration Serial bit length must be chosen for a quantized signal with a precision of.1 0 and 2 microstrains Sampling frequency of 250 Hz for adequate signal recovery Transmitting antenna must be oriented to prevent polarization mismatches with the receiver Hardware and Software calibration is required prior to session to compensate for physical inadequacies

8. Design Explanation Hub Blade Pivot Nonlinear stiffness spring POT Strain Gauge

9. Design Explanation Position Transducer Battery Pack Power Source TransmitterTransmitter 2:1 Mux Sampler/ A/D Converter Wheatstone Bridge Amplifier Signal Conditioner Strain Gauge KEYPowerSignal EM Signal

10. Design Explanation Helicopter House Power 1:2 Demux D/A Converter/ Buffer Buffer KEY Power Signal EM Signal ReceiverReceiver LaptopLaptop Internal Sensor Package DAQ PCMCIA

11. Simulation Results Power Consumption Power Consumption Sampling and Data Conversion Sampling and Data Conversion Control Circuit Control Circuit Signal Conditioning Signal Conditioning

12. Power Consumption +15 Volt Rail -15 Volt Rail +5 Volt Rail

13. Power Consumption Minimum Battery Life

14. Sampling and Data Conversion Computer simulation of baseline case, blade lead angles with Duffing stiffness spring

15. Sampling and Data Conversion 5Hz sampled at 50Hz

16. Sampling and Data Conversion 5Hz sampled at 250Hz

17. Control Simulation f = 1.44/((R2+2R3)C1)

18. Control Simulation 2ms 500 Hz (250 Hz / channel)

19. Signal Conditioning (Amp) Wheatstone Bridge Output (V12 – V11) Gain Adjust Output

20. Signal Conditioning (Amp) Wheatstone Bridge Terminal V1 and V2

21. Signal Conditioning (Amp) Gain = 333 V/V Gain = 333 V/V difference amplifier Amplified Signal ±7.5mV Input Signal

22. Signal Conditioning (Filter) 2-pole Butterworth Filter (f c = 15Hz)

23. Signal Conditioning (Filter) f c = 15 Hz 5Hz => -.041453 2. 5Hz => -.00235 dB attenuation (-40dB/dec rolloff)

24. Future Improvements Automated helicopter control system Implement remote transmitting on/off switch Battery reduction circuitry Graphical User Interface (GUI)

25. Helicopter Data Acquisition System ECE 4512 Senior Design I The End