Magnetic Detection System R&D - Electrans
About This Project
During my work-term at Electrans Technologies, I was tasked with doing R&D for optimizing the cost and effectiveness of an existing system in the companies robotic product. The system involves tracking a target over a defined range of motion. Since hall effect sensors are popular in modern vehicles, the R&D project was to determine if it could be an appropriate cost effective solution.
Determining the Points of Interest
Desmos Plot
By taking measurements in CAD, and doing some trig, key points were determined.
The two ends of the sweep were determined
4 points in between spaced by 2 degrees
This was then plotted in desmos to illustrate the sweep of values.
Simulations to Determine Magnetic Flux at Key Points
Sample Simulation
Position: End of sweep
Magnet Shape: Ring
OD: 15 mm
ID: 4.5mm
Thickness: 3.5 mm
Grade: N42
Simulation Sample Plot
This simulation was done at each key point for 10 magnets. Using the data acquired and the plots, 4 were selected for experimental testing.
3D Hall Effect Sensor Resolution
Calculations included to see if simulated positions provide significantly distinct magnetic flux values for the sensor.
Magnetic flux sensing of +/- 160 mT in each direction
12 Bit resolution
Calculated resolution is 0.0635 mT
This in addition to the simulated results indicate that the sensor is more than sensitive enough for this application
Experimental Testing
Experimental Testing Jigs
To accurately test and characterize the 4 magnets, I FDM printed jigs for each position. From here I used the 3D hall effect sensor evaluation kit to take experimental measurements in each position.
This characterized the curve for each magnet and also determined if each key point is significantly distinct from one another.
Results
The 4 Magnets were characterized as seen on the right.
Magnet 1,2, and 3 provided significantly distinct magnetic flux values between each key point
Standard deviation for each key point was < 0.2 mT for all magnets
Magnet 3 is preferred since it provides reliable readings and produces a weaker magnetic field meaning it is less of a contaminant
