Helicopter Data Acquisition System ECE 4512 Senior Design I

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

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

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

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

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 ( MHz) for a practically sized antenna

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

Design Explanation Hub Blade Pivot Nonlinear stiffness spring POT Strain Gauge

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

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

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

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

Power Consumption Minimum Battery Life

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

Sampling and Data Conversion 5Hz sampled at 50Hz

Sampling and Data Conversion 5Hz sampled at 250Hz

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

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

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

Signal Conditioning (Amp) Wheatstone Bridge Terminal V1 and V2

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

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

Signal Conditioning (Filter) f c = 15 Hz 5Hz => Hz => dB attenuation (-40dB/dec rolloff)

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

Helicopter Data Acquisition System ECE 4512 Senior Design I The End