4WD Turning Difficulties

[pfreivald]

Four-wheel tank drive on a ~140lb robot seems about as easy to turn and maneuver with as a car towing a small trailer on a very icy road... Unreliable at anything approaching speed, but something you can definitely live with -- especially if there are no ditches into which one might slide, and the intactness of one's body is not on the line.

I didn't notice that skid steering was any better than the steering of an actual car on 1/4" of ice... and I had a chance to test that out in the school parking lot just this past Wednesday! (We had a snow day because of an ice storm, so I did a little 'research' with my car.)

Patrick

[kramarczyk]

I took a few minutes to update the spreadsheet from the beginning of the thread to include the forces from the trailer in the FBD. At present I still do not have the physical properties (i.e. an adequate trailer) to validate the spreadsheet, but it does seem to agree with what I have seen in videos from other teams. If some folks concur that the physics are correct I'll put it up in the white papers. Let me know if it is worthwhile.