Wireless Test Instrumentation System for Rotating Parts

Wireless Test Instrumentation System for Rotating Parts

ECE Team 167Lawrence BoganJeremy Neaton

Adam BienkowskiMichael GolobME Team 29

Sean HandahlKen ThompsonCaleb Browning

Paul Inguanti - Company AdvisorChris Winslow - Senior Test Engineer

Rajeev Bansal - ECE Project AdvisorRobert Gao - ME Project Advisor


Outline

ME Team 29 - ECE Team 167Senior Design Fall 2012

1. The Problem2. Project Goals3. Electrical Components4. Electronics Package5. Test Rig6. Energy Harvesting7. Budget8. Timeline


Problem


• Collect and wirelessly transmit data pertaining to the tail rotor pitch change bearing in S-92 helicopter

• Wireless link to eliminate need for wired interface between rotating and non-rotating parts

• Battery must last at least 1 year, 3 years recommended

• Electronics cavity is 1.5" diameter by 5.1" long• Components will be in a noisy environment with

high vibrations and temperature


Problem



Project Goals


• ECEo Measuring of sensor datao Signal processing, storage, and transmissiono Power management

• MEo Design and creation of test rigo Energy harvesting/energy generation to

power/recharge systemo Mounting and installation of sensors and transmitter


Block Diagram



Wireless Transmission


• Wireless device must be able to transmit data over a distance of about 40 feet. The measuring system is located in the tail rotor and the stationary receiver is

located in the cabin.

• ZigBee (Wireless chip):o Provides low power consumption o Transmits data at a far distanceo Low Cost

• Part Number: AT86RF231o 14 mA Active Currento .02 μA Idle Current


Accelerometer


• The accelerometer needs to transmit the vibration data it receives to the

microcontroller.

• Accelerometer needed to have an interrupt. This will tell the microcontroller when

to start recording the data.

• Our sensor needed a minimum bandwidth of 400Hz, so we found an

accelerometer with an adjustable bandwidth in that range.

• The power consumption needed to be at a minimum. We were able to find an

accelerometer with an active current of 11μA.

• This sensor is extremely small at 3 x 3 mm.

LIS3DH


Microcontroller


• Needs to be able to communicate with sensor, memory and transmitter

• TI Ultra-Low Power Microcontrollero 312µA Active Currento 2.6µA Idle Currento SPI and IO interfaces


Memory


• Needed to store sensor data• If data is collected continuously over the maximum specified

time of 12 hours between data accesses, this will produce too much data to store and transmit given power and space constraints

• Options:o Time synchronous averagingo Periodic Samplingo Transmit when available memory is full

• Cypress 16Mbit Low Power SRAMo 2mA active currento 10µA idle current


Battery


• Assuming constant sampling, transmission when memory is full, 16-bit samples, 1.25kHz sampling rate:Total battery capacity needed is 10.5Ah

• We found a lithium thionyl chloride battery, The Tadiran 5930 battery has 17Ah.

Part Data Acquisition Current Transmission Current Idle Current

Sensor 11 µA 0.5µA 0.5 µA

Memory 2mA 2mA 22µA

Microcontroller 220µA 220µA 0.5µA

Transceiver 0.02µA 14mA 0.02µA

Totals 2.23mA 16.22mA 23µA


Electronics Package



Test Rig



Energy Harvesting


• Unnecessary to meet minimum design requirements, but will extend the life of the electronics past one year.

• Researched thermal, vibration, or magnetic energy harvesting methods• Vibration is the only viable and relatively constant in helicopter; turns

strain into energy, energy created is relatively small, and the system may be too large to implement

• A custom rectifier board is needed: commercial boards are too large. If we cannot make a custom board we cannot use energy harvesting. Energy output is dependent on how much space is left for the unit to vibrate.


Budget


• Our budget, from Sikorsky is $4,000 and will cover the following: Wireless Transmitter- $5 Microcontroller- $10 Sensors- $2 Battery- $25 Memory- $16 Antenna- $8 PCB- ~$100 Energy Harvester and Equipment- ~$100 Representative Rotating System- ~$500

TOTAL=$766 REMAINING: $3234


Timeline


November December January February March April


Questions?


Wireless Test Instrumentation System for Rotating Parts

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