pic: FRC488's Octocanum Ver 2.0

[JohnGilb]

Originally Posted by Ether

Mecanum is not hard to program. It is very straightforward. The same is true of field-oriented drive.

If your robot had superior control, I suspect the reasons are probably:

1) superior craftsmanship and attention to detail of the mechanical design (wheel and frame alignment, leveling, weight distribution, minimal and consistent drivetrain friction, carefully assembled and adjusted mecanum wheels)

2) attention to detail of the electrical design (proper wiring to motors and gyro, selection of gyro with minimal drift, etc)

3) well-designed driver interface (match the driver interface to the driver)

4) skilled drivers with lots of practice

Granted, the 488's 2011 machine was built quite well, but there were still all sorts of mechanical inconsistencies. The center of gravity moved around significantly as the arm moved, generally there was more weight in the back (and slightly more on the left side, I believe), not to mention occasionally getting rammed around or crashing into objects.

The base aspect of converting a desired vector/rotation into wheel speeds is pretty easy (it's even included in the WPI libraries), but we did a lot of additional work so the robot would _actually_ move the way you intended. There were many PID operations that more or less worked in concert to allow smooth robot control. It was essentially a solved problem from a theory perspective, but still required a lot of code in order to operate well.