Swerve Gear Box

[AdamHeard]

Originally Posted by artdutra04

These are both different methods for controlling a "unicorn" drive, with the prior being better for autonomous path planning and the latter being easier for human control. For the prior, there are simply too many inputs for a person to feasibly and intuitively control, but this method (rotation around any arbitrary instantaneous center) is best suited for advanced path planning/navigation. For example, if you wanted to autonomously drive a robot along lines, arcs, or splines while rotating the drive base, the first one would be the chosen control scheme. For this drive mode, everything is broken down into driving straight, driving in arcs, driving along splines, etc and the control inputs are based upon the desired states of these actions.

The latter scheme, as Adam pointed out, is similar the prior, but much simpler (less inputs, less inverse kinematics). This makes it easier for someone to control it, but with has "less control" over the outputs of the system. However, this can be overcome by "transferring" some of the complicated "inverse kinematics" back to the human driver: by training, the human driver could learn to control the three inputs they are given in this scheme to produce very similar results to the above control scheme (e.g. the driver could drive in an arc/spline while rotating by learning how to perfectly alter and coordinate the X-Y vector and Z-rotation joysticks).

I really don't view the method with three inputs as being too difficult to control, for the general case of FRC driving (all situations covered by one set of controls) it's a better match. It also is a 1:1 match to the style of controls students are all familiar with from exposure to video games.

I guess what is better for human control is more a matter of opinion than anything.