Contactless Angular Position Sensor
Mid-Semester Design Presentation
Senior Design Presentation
October 8, 2009
Team Members
Eugene Sandberg
Computer Engineer
Christine Bratton
Electrical Engineer
Matt Landry
Electrical Engineer
Tasks:
-Construct Test Setup
-Program Microchip
-Website
Tasks:
-Research Magnets and Sensors
-Program Microchip
-Output Stage
Tasks:
-Research Magnets and Sensors
-Output Stage
-Packaging
Aram Lee
Electrical Engineer
Jeremy Lewis
Computer Engineer
Tasks:
-Research Magnets and Sensors
-Program Microchip
Tasks:
-Construct Test Setup
-Packaging
-Layout
Outline
• Problem Statement
• Solution Diagram
• Constraints
– Technical
– Practical
• Alternatives to Original Solution
• Progress
– Timeline
Problem
A-Arm
Endcap/Sensor
Problem With Current Design
The current sensor
fails often.
The Army believes
that it is due to the
mechanical contact.
Solution - Hall Effect Sensor
Overview of Proposed Solution
Magnet
• Generates a
magnetic
field.
Sensor
• Outputs a
signal
relative to
angular
position of
magnetic
field.
Microprocessor
• Processes
the signal
from the
sensor.
DAC/Amp
• Outputs
analog
voltage.
(0-24V)
Constraints
•Technical Constraints
•Practical Constraints
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 less than
20ms or less.
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.
Practical Constraints
• Problem
• Sustainability
– The CAPS must be contactless.
Practical Constraints
• Problem
• Compatibility
– Must Fit in End Cap
– Same Casing
Alternatives for Angular
Position Sensing
•Optical
-Grease Interference
-Outside of Vehicle
-Particle Interference
Alternatives for Angular
Position Sensing
•Hall Effect Sensor
-No particle interference
-Operates in Endcap
-Sensitive to Magnetic
field
Alternatives
Angular Position Sensors
MLX90316
KMA200
• Hall Technology
• Magnetoresistive
• Digital SPI Output
• Analog and Digital SPI Output
• Specify Default Mode when Ordering • Default Mode is Analog
• Currently Being Tested
• Will be used for Initial Testing,
• 360 Degree Range
Calibration of Test Setup
• 180 Degree Range
Progress - Parts
MAX5312EAE
• DAC
• 0V-8V Output
• 12Bit Percision
PIC24
• Process Sensor Signal
• Talks to the
MAX5312EAE
LM7321MA
• OP AMP
• 3 to 1 Amplification
• Will output voltage of 0- 24
• 24V supply
Progress-Test Setup
Test Setup
Progress
Magnet Evaluation
Magnet A (Largest Magnet)
Voltage at 45 Degrees
Voltage at 90 Degrees
Voltage at 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
Progress
Timeline
8/18
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
8/28
9/7
9/17
9/27
10/7
10/17
10/27
References
•Karahalis, Alex. “Contacless Angular Position Sensor.”
August 11, 2009.
•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].
• Quasdorf, Joachim. “A Case Study: MR vs. Hall Effect for
Position Sensing.” [Online]. Available:
http://www.sensorsmag.com/sensors/article/ [Accessed:
October 2009].
Questions
?????