mid-semester design presentation senior design presentation october 1, 2009 contactless angular...

Mid-Semester Design PresentationSenior Design Presentation

October 1, 2009

Contactless Angular Position Sensor

Team Members

Eugene SandbergComputer Engineer

Tasks:-Construct Test Setup-Program Microchip

Christine BrattonElectrical Engineer

Tasks:-Research Magnets and Sensors-Program Microchip-Output Stage

Aram LeeElectrical Engineer

Tasks:-Research Magnets and Sensors-Program Microchip

Jeremy LewisComputer Engineer

Tasks:-Construct Test Setup-Packaging-Layout

Matt LandryElectrical Engineer

Tasks:-Research Magnets and Sensors-Output Stage-Packaging

Outline

• Problem• Solution• Constraints

– Technical– Practical

• Alternatives• Progress

Problem and Solution

Problem Statement• The current sensor fails due to shaft mechanical

contact. • Each failure results in a significant cost for the Army since

they must replace the entire A-Arm.

Solution• Eliminate the mechanical contact by using a Hall effect sensor and a magnet attached to the rotating portion of the A-Arm. • The raw data output will be processed by the PIC24 and sent to

the output stage for amplification.• A test setup will be constructed that will allow us to test the

chosen sensors and magnets.• Finally, a mechanical prototype will be constructed using a 3D

CAD program.

Overview of Proposed Solution

Magnet

• Generates a magnetic

field.

Sensor

• Outputs a signal relative

to angular position.

Microprocessor

• Processes the signal from the sensor.

DAC/Amp

• Outputs analog

voltage. (0-24V)

System supply is 24V.

Constraints

• Technical Constraints

• Practical Constraints

Technical Constraints

• The CAPS must operate between -40 to 70 degrees Celsius

• The CAPS must be accurate to .1 degrees and measure an angle of 90 degrees.

Technical Constraints

• The CAPS must be driven by a 24 volt input and output a linear DC voltage ranging from 0 to 24 V.

• The CAPS must draw less than 24 mA.

• The CAPS must have a response time of 24 ms or less.

Practical Constraints

• Problem• Sustainability

– The CAPS must be contactless.

Practical Constraints

• Problem• Manufacturability

– The design must be easily produced and manufactured by an army subcontractor.

– Must Fit in End Cap – Same Casing

• Optical-Grease Interference-Outside of Vehicle-Particle Interference

• WiFi/Bluetooth-Complicated-Extra Power Source

Alternatives

Alternatives

Magnet A (Largest Magnet)

45 Degrees 90 Degrees 135 Degrees

5mm 1.08 2.5 3.64

10mm 1.07 2.49 3.67

15mm 1.08 2.52 3.66

20mm 1.09 2.48 3.62

25mm 1.09 2.48 3.61

30mm 1.1 2.4 3.61

Magnet B (Second Largest Magnet)


5mm 0.726 2.5 3.74

10mm 0.799 2.49 3.62

15mm 0.906 2.49 3.54

20mm 0.96 2.43 3.52

25mm 1 2.43 3.5

30mm 1.06 2.44 3.5

Magnet C (Third Largest Magnet)


5mm 1.43 2.99 3.88

10mm 1.49 2.94 3.85

15mm 1.49 2.87 3.88

20mm 1.49 2.81 3.88

25mm 1.47 2.79 3.87

30mm 1.48 2.75 3.85

Magnet D (Smallest Magnet)


5mm DATA INCONSISTINT MAGNET TOO WEAK






Magnet Comparison

Alternatives

Sensors, MAX548A, and PIC24 for Test and Implementation

MLX90316• Rotary Position IC• Hall Technology• Output Signal to PIC

PIC24• Process Sensor Signal• Talks to the MAX548A

KMA200• Analog Output• Will be used for initial testing,

Calibration of Test Setup

MAX5312EAE• DAC• 5V-10V

LM7321MA• OP AMP• Will output voltage of 0- 24

Progress

Test Setup

• Built Simulation Control Arm from PVC

• Mounted Arm on Test Bench

• Attached Magnet to Rotating Portion of Arm

• Mounted Sensor Setup Facing Magnet

-Sensor setup will consist of PIC24HJ64, a Hall Effect sensor, and the necessary circuitry

• Mounted Old Sensor on Backend for Comparison

Progress

Tasks/Dates

Research Sensor and Magnets

Construct Test Setup

Evaluate Angle Sensor 1

Output Stage

Investigate 3D CAD Packaging

Evaluate Angle Sensor 2

Interface with Microprocessor

Package Design

8/18 8/28 9/7 9/17 9/27 10/7 10/17 10/27

References

• [1] Karahalis, Alex. “Contacless Angular Position Sensor.” August 11, 2009.

• [2] SPG Media Group Ltd. “Stryker 8-Wheel Drive Armoured Combat Vehicles, USA.” 2009. [Online]. Available: http://www.army-technology.com/projects/stryker/ [Accessed: August 30, 2009].

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Questions

mid-semester design presentation senior design presentation october 1, 2009 contactless angular...

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