Swerve with a twist

[Ryan_Todd]

Originally Posted by Harshizzle

Yeah, this is exactly what I was attempting to describe.
[...]
This design cannot do simultaneous steering and moving with any sort of accuracy, but in cases when that is not needed (I'm picturing something like an amazon warehouse robot), this could be an option.

Thanks for confirming my interpretation.

Personally, I would be less interested in this concept as a "Plan A" design than as a case study in control systems design. As discussed above, this still has the same total number of outputs as a traditional independently-steered swerve drive, but it nonetheless manages to be an under-actuated system; this would therefore save relatively little in cost and complexity, while giving up a fair amount of controllability in the process. If you're looking to save on cost and complexity, after all, it's hard to beat a good old-fashioned skid-steer setup.

Don't get me wrong, however, because I strongly believe that this project would still be completely worthwhile-- and indeed, quite valuable in the real world! The key is to shift gears a bit, and instead view this as a research project.

As a software engineer in the automotive industry, I always need to be mindful of the fact that the real world isn't perfect; things go wrong all the time, and my work needs to be able to take that in stride. As a result, my job is not simply to get my component to work right, but rather to ensure that even if the rest of the system is compromised to the point where my component cannot work right, it will still never work wrong. If that means slowing down the engine to prevent it from overheating (or stopping the engine altogether to prevent it from exploding), then so be it!
This kind of thinking is essential whenever the end user's safety is at stake, and strongly advisable in many other applications.

With this in mind, can you see a way that it might be helpful to have an understanding of how to control a swerve drive platform, even if one or more axes of control are disabled, modified, or behaving abnormally?

(It may, for example, be advantageous to design a swerve drive specifically to allow for the possibility of falling back to an alternative control scheme like the one described above.)