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MagBot Model 1
VEX Magnetic Climbing Robot

The VEX Magnetic Climbing Robot was designed to demonstrate how a simple robot could accomplish the technical challenge of climbing a metallic surface.  There are numerous commercial applications for this type of robot.  Oil refineries must inspect the inside of their storage containers.  iRobot has had great commercial success with their Roomba Vacuuming robot as well as their numerous other cleaning robots.  A robot capable of cleaning or inspecting metallic surfaces of oil tanks, buildings, water towers, and arenas would be commercially valuable.

Magbot 1 uses (4) Neodymium Rare Earth Magnets attached to lever arms positioned just below the axles of the robot.  These powerful magnets provide the necessary adhesion to firmly attach the robot to the climbing surface.  The magnetic adhesion itself is not sufficient to allow the robot to climb.  The magnets are attached to the robot chassis with tensioned lever arms.  These lever arms generate the force necessary on the wheels to provide adequate traction for climbing.  During initial testing it was determined that excessive tension on the lever arms led to an inappropriate reduction of the magnetic surface adhesion.  The reduction in magnetic surface adhesion led to gravity induced structural deformation of the robot on several occasions.


Built and Designed by: Beener  See the Next Generation Model 2 & Model 3


Magbot Technical Specifications

Robot Technical Specifications

Chassis Aluminum
Weight 3.45lbs (1564.89g)
Dimensions (L x W x H) 12" x 9" x 2.5" (304.8mm x 228.6mm x 63.5mm)
Wheels (8) 2.75" VEX Robotic Wheels (69.85mm)
Motors (4) VEX Continuous Rotation Motors
Electronics (1) VEX Signal Splitter
(1) RF Receiver Module
Drivetrain Continuous (4) wheel drive. 
1:1 gear ratio
Dual drive shafts with (2) motors driving each shaft.
Torque 26 in/lb @ 100 rpm (1.45 m/kg)
Min/Max Voltage 4.4 - 15 Volts

Magnet Technical Specifications

Magnets (4) Neodymium Rare Earth Magnets
Dimensions 25mm diameter
4mm inner diameter
6mm thick
8mm diameter x 3mm deep countersink
Plating Nickel
Surface Gauss 3000
Magnetized Axially through 6mm thickness
Coercivity 12440 Gauss
Remanance 11.76 kOe
Max Energy Product 36.96 MGOe
Pull Strength 20.4kg (45lbs)
Weight 20.61g (0.7oz)
The magnets were purchased from Gaussboys.  They were the cheapest place I could find for Rare Earth Magnets.
I also called them up and they provided excellent technical support on determining which magnets would be best for this application.

Magbot Photos


Click on image to Enlarge


The tension arms can be clearly seen.  During testing the rubber bands were placed in several locations on the lever arms and different size rubber bands were used.

Initially there were only 4 wheels.  Additional wheels were added to increase the traction during vertical ascent..

The magnet is shown here under the drive shaft.  This provides the down force as close as possible to the contact patch of the wheel.

The drivetrain uses (2) motors to drive each driveshaft.  The bevel gears are the same on the motors and the wheels providing a 1:1 gear ratio.

This shows the placement of the magnet in proximity to the axle.  The nylon spacer prevents the magnet from making contact with the axle.

The drive shafts are supported at (5) points along the axis.  The smaller motor shafts and wheel axles are supported at (2) points.

This is a detailed photo of the wheel axle assembly.  Notice how the bevel gear is shimmed with small washers.

This is a detailed photo of the motor shaft assembly.  Notice how the center structural cross member is supporting the primary drive shafts.

An important design feature is to have the motors and magnets behind the wheels.  In the event of a reduction in magnetic surface adhesion the wheel axles can be straightened easier than replacing the expensive motors and magnets.

The design of the robot was kept as simple as possible.  This allowed for quick and easy repairs.  The chassis was built entirely of aluminum to keep the weight to a minimum.


YouTube Videos - Successes and Failures
Additional Videos - InnovationFirst Channel