6WD Pros and Cons

[Madison]

Originally Posted by Daniel_LaFleur

Hmmm ... maybe I'm being a dolt here and not understanding.

Each axle on a 6WD robot has 33% of it weight over it (assuming level loading).
Each axle of a 4WD robot has 50% of it's weight over it (again assuming level loading).

A 6WD robot has to overcome the traction of 2 of it's axles in order to turn, or in otherwords overcome (66% of it's weight over wheels x CoF).
A 4WD robot only needs to overcome the traction of 1 of it's axles (or 50% of it's weight over wheels x CoF).

Again, maybe I'm being a dolt here and not seeing the obvious, but why would it be easier to turn against more weight on wheels?

** as a note: this is all theoretical. It assumes many things which in nature just don't happen such as weigh being perfectly distributed over each wheel, the plane that the wheels sit on is perfectly flat, all wheels touch the plane in 1 (and only 1) point, the effective suspension for all wheels are identical, etc **

I

In the instances above, you're assuming a different center of mass in each case. If the weight is distributed evenly across the robots, the center of mass will be in the center of the robot and it will, thus, turn about that point.