VEX Mecanum Vs. FRC Mecanum

The 4” VEX mecanum wheels strafed three Sack Attack sacks (that is, 15.5”). That’s about 6:5 strafing distance to wheel circumference. More tests were necessary to make sure that ratio exists on the FRC robot as well.

How to get AndyMark 775 motors with 100:1 Vex Pro Versa Planetary Gear Set to work

These were our tests to try to get the VEX Pro 100:1 Planetary Gear set to work with the AndyMark’s 775 motors.  These motors will be used for our intake rollers.

  1. We took the gear box apart and looked at the individual gears to see if anything is inside.
  2. We decomposed the gearbox and tested the motor again. Unfortunately, that did not fix the problem.
  3. We tested the motor with a power source.  A 12V battery gave different results than a power source that is plugged into the wall.
    1. Plugging it into a wall power source gave a significant decrease in energy It was enough to run the motors without the gearbox.
    2. When the gear boxes are connected the motors, the motors will then not spin.  This lead to the thought that the gearboxes have too much torque for the motors to spin.
    3. Luckily, when plugging the motor and gearbox to the 12V battery, it worked better.  This may be due to a more consistent feed of electricity through the battery rather than the Power Source.

Weight Distribution (In Progress)


Weight (in pounds)



Wheels (x4)

1.5 (6)

Power Distribution


Motors and Transmissions (x4)

7.5 (30)

12 Victors; 2x Victors (x6)                                         5/8 (3.75)
Super Structure                                                           6

Total so far                                                                  53.5 pounds

CAD of thoughts

We have decided to have a bar going from the top of the front tower to the back of the side rails to provide more structure.  We have also decided to have two arms for the intake because earlier, the ball would not properly get through.  Also we changed to having the two intake wheels by about six inches to allow more surface area on the ball.

2014-01-17 Friday Build Notes

  • We’ve done more work on the low goal: mounting hinges and connecting sides to each other. We’ve had a bit of trouble figuring out how the sides fit together, however.
  • We’ve discussed various ways of winding up and releasing the catapult: besides the Choo-choo design, Christian started prototyping a design involving two worm motors and a pneumatic. This transmission is a two speed with worm drive that engages with pneumatics.
  • Classmate was configured and connected. The control system is now working, sans joysticks. We were able to receive video from the axis on the classmate and power a motor in autonomous.