Torque Problem?

[LegoMindstormsmaniac]

@Brian He

Mecanum Wheels In H-drive
http://youtu.be/b_ENv9lxChA

• Summary of problems:

1. Robot cannot travels when placed on the field mats, but it was able to do so for the first time(moved less than a meter).
2. The back wheels cannot spin continuously to one direction only, and there’s a pattern of timing when they pause. They pause very shortly but multiple times in one cycle, and both wheels act the exact same way.
3. The back wheels can rotate the robot to one direction, but barely to the opposite way.
   My Questions:
   Are the above problems related with one or multiple factors? (Torque, the constructions, the programming etc.)
   How do you know is there enough torque for moving the robot?
   **Is the a way to keep the 4:1 ratios with Mecanum wheels in a H-drive while improving the driving power? (Things like increasing the contact area of the robot with the mats so the weight spreads out more etc.)

The reason your robot is not functioning correctly is not weight distribution. The problem is that your gear ratio is too fast for the weight of your robot, and the torque of your motor configuration. Adding more motors to your drive could help, but as a rough estimate, I would say it would take all 10 of your motors on your drive with a very light robot (drivetrain only and made out of aluminum) to be able to get your 1:5 gear ratio running on the mechanum wheels.

In short, a 1:5 ratio on your drive with mechanum wheels is just not going to work on a typical VEX competition robot, especially one that is made out of steel. I suggest changing this ratio to a 3:5, changing your 12-tooth metal gears on the wheels to 36-tooth plastic gears.

~Jordan