Team 4206 Pre-Season Drive Module (In Progress)

[DavisDad]

Originally Posted by jbsmithtx

This is Team 4206's preseason drive module (or at least part of it). The rest of the model is a little messy right now. Any comments, thoughts or suggestions would be much appreciated... The large arms on the side will be actuated by a pneumatic piston

Hi jbsmithtx,

We're working on a similar design using VEX 4" Mecanums. We built a prototype to test performance of wheels, motor controller, and gearmotor/encoder combination. We used the Matrix system for cost and availability reasons; the Matrix gearmotor has the encoder built in and the Matrix controller handles up to 4 motors. We really like the VEX Mecanum wheels; they roll smoothly and the price is very reasonable.

Our competition design is currently:



For the testing prototype we built:





We want to fold the motor tighter to the side using a miter gearbox; at least on the front. This will provide more room for the collection mechanism.

Things we like about the prototype:

• Motor controller built in PID speed control worked well (RobotC code)
• Teleop control is very nice for omni-directional control
• Speed vs. power is good (quantitative date to come)
• Fabrication was fairly straight forward (see cons)
• Square shaft for wheel eliminates hub

Cons:

• Couldn't get encoder position control to work with the built in Matrix RobotC code
• Square shaft VEX to 4mm motor shaft coupling was tricky. We had to learn how to broach a square hole and weld 2 pieces of the coupler together.