Helicopter Data Acquisition SystemHelicopter Data Acquisition System

ECE 4512 Senior Design IECE 4512 Senior Design I

Team MembersTeam Members

David PaulDavid Paul

Aaron HillAaron Hill

Robert McInnisRobert McInnis

Jason SchemmelJason Schemmel

Dr. Rob KingDr. Rob King (Advisor)(Advisor)

Team ResponsibilitiesTeam Responsibilities Aaron Hill (Power)Aaron Hill (Power)

Battery selection and power consumption simulation

David Paul (Controls)David Paul (Controls)

Control circuit design and simulation

Jason Schemmel (Communications)Jason Schemmel (Communications)

Antenna simulation and transmitter/receiver simulation

Robert McInnis (Communications)Robert McInnis (Communications)

Signal conditioning, sampling, and data conversion

MotivationMotivation

Utilizes all aspects of Electrical EngineeringUtilizes all aspects of Electrical Engineering

High Level of DifficultyHigh Level of Difficulty

Can be used in many other applicationsCan be used in many other applications

Improvement of existing techniques Improvement of existing techniques

Problem StatementProblem 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 RequirementsDesign Requirements

Control CircuitControl Circuit

PowerPower

Signal ConditioningSignal Conditioning

Transmission FrequencyTransmission Frequency

Design a control circuit to synchronize MUX/DEMUX and data converters

Batteries must be selected toprovide 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

Design RequirementsDesign Requirements

Data TransmissionData Transmission

Sampling RateSampling Rate

Antenna PolarizationAntenna Polarization

CalibrationCalibration

Serial bit length must be chosen for a quantized signal with a

precision of .10 and 2 microstrains

Sampling frequency of 250 Hz for adequate signal recoveryTransmitting 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 ExplanationDesign Explanation

Hub

Blade

Pivot

Nonlinear stiffness spring

POT

Strain Gauge

Design ExplanationDesign ExplanationPosition Position

TransducerTransducerPosition Position

TransducerTransducer Battery Battery Pack Pack

Power Power SourceSource

TransmitterTransmitterTransmitterTransmitter

2:1 Mux2:1 Mux2:1 Mux2:1 Mux

Sampler/ Sampler/ A/D A/D

ConverterConverter

Sampler/ Sampler/ A/D A/D

ConverterConverter

Wheatstone Wheatstone BridgeBridge

Wheatstone Wheatstone BridgeBridge

Amplifier Amplifier Signal Signal

ConditionerConditioner

Amplifier Amplifier Signal Signal

ConditionerConditioner

Strain GaugeStrain GaugeStrain GaugeStrain Gauge

KEYKEY

PowerPower

SignalSignal

EM SignalEM Signal

Design ExplanationDesign Explanation

Helicopter Helicopter House House PowerPower

1:2 Demux1:2 Demux1:2 Demux1:2 Demux

D/A D/A Converter/Converter/

BufferBuffer

D/A D/A Converter/Converter/

BufferBuffer

KEY

Power

Signal

EM Signal

ReceiverReceiverReceiverReceiver

LaptopLaptopLaptopLaptop

Internal Internal Sensor Sensor

PackagePackage

Internal Internal Sensor Sensor

PackagePackage

DAQ DAQ PCMCIAPCMCIADAQ DAQ

PCMCIAPCMCIA

Simulation Results Simulation Results

Power ConsumptionPower Consumption

Sampling and Data Conversion Sampling and Data Conversion

Control CircuitControl Circuit

Signal Conditioning Signal Conditioning

Power ConsumptionPower Consumption

+15 Volt Rail

-15 Volt Rail

+5 Volt Rail

Power ConsumptionPower Consumption Battery Discharge Rate

14.5

15

15.5

16

16.5

17

0 10 20 30 40 50 60 70 80

Time (min)

Vol

ts

Negative 15 Volts

Positive 15 Volts

Minimum Battery LifeMinimum Battery Life

Sampling and Data ConversionSampling and Data Conversion

0 1 2 3 4 5 6 7 8 -100

-80

-60

-40

-20

0

20

40

60

80

100

Time (sec)

Bla

de L

ead

Ang

le (

deg)

Baseline Case w/ Duffing Spring

Computer simulation of baseline case, blade lead Computer simulation of baseline case, blade lead angles with Duffing stiffness springangles with Duffing stiffness spring

Sampling and Data ConversionSampling and Data Conversion

5Hz sampled at 50Hz

Sampling and Data ConversionSampling and Data Conversion

5Hz sampled at 250Hz

Control SimulationControl Simulation

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

Control SimulationControl Simulation

2ms

500 Hz

(250 Hz / channel)

Signal Conditioning (Amp)Signal Conditioning (Amp)

Wheatstone Bridge Output (V12 – V11)

Gain Adjust Output

Signal Conditioning (Amp)Signal Conditioning (Amp)

Wheatstone Bridge Terminal V1 and V2

Signal Conditioning (Amp)Signal Conditioning (Amp)

Gain = 333 V/V

Gain = 333 V/V difference amplifier

Amplified Signal±7.5mV Input Signal

Signal Conditioning (Filter)Signal Conditioning (Filter)

2-pole Butterworth Filter

(fc = 15Hz)

Signal Conditioning (Filter)Signal Conditioning (Filter)

fc = 15 Hz

5Hz => -.0414532.5Hz => -.00235

dB attenuation

(-40dB/dec rolloff)

Future ImprovementsFuture Improvements

Automated helicopter control system

Implement remote transmitting on/off switch

Battery reduction circuitry

Graphical User Interface (GUI)

Helicopter Data Acquisition SystemHelicopter Data Acquisition System

ECE 4512 Senior Design IECE 4512 Senior Design I

The End