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Unread 02-11-2010, 10:03
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Re: Mecanum. What's Best

Quote:
Originally Posted by JesseK View Post
Here are what I consider 'bloated'
  • 2 Joysticks that control different degrees of freedom**.
  • 1 Joystick that has a "twist" action for a z-axis rotation, in which users (from novices to veterans) unknowingly twist it ever so slightly while trying to strafe
  • Control software code where (as an example of negligible amounts) 10% more rotation control input from a joystick translates to 10% more rotational output from the robot even while the robot is strafing
  • Overly sensitive controls where fine muscle movement is needed (like game pad thumb sticks) for the difference between (example) strafing left and strafing the forward left diagonal. This is particularly noticeable when combined with the 3rd bullet.

...starting with something fundamentally simpler would also alleviate the problem with less impact on the robot's schedule. In other words, the drivers get more practice learning the robot's interaction with game elements rather than learning how to make the durn thing move as expected.
Thanks for making that clearer. I completely agree with the general point you are making (about making a driver interface with a quick learning curve).

I think we disagree slightly on the implementation of that goal, specifically the first two bullet points:

2 Joysticks that control different degrees of freedom

Experience has shown that there is a mecanum driver interface with different degrees of freedom on 2 joysticks which has virtually no learning curve for a driver with prior tank-drive experience. It's an implementation of the "Tank-drive" approach that you mentioned. The left and right joystick Y axes control the vehicle just like tank drive, and the right (or left) X axis controls strafe (but only when a button is held down). More detail available here.

1 Joystick that has a "twist" action for a z-axis rotation, in which users (from novices to veterans) unknowingly twist it ever so slightly while trying to strafe

The above objection is valid, but is easily mitigated by adjusting the gain curve of the Z-axis so that small signals have little or no effect. See this post for more detail.