Mecanum drive train idea.

[MCeGEAR]

While at school i came up with an idea for a mecanum drive train that uses 8 mecanum wheels, no omni wheels used.
/1 \5
\2 /6

/3 \7
\4 /8

wheels 1 is connected to wheel 3 and wheel 2 to 4. Wheel 5 to 7 and 6 to 8.
Now, do you think this would possible work? and would it be superior to a traditional 4 wheel or some how just not work at all? Thank you very much in advance.

[Vikesrock]

My suggestion would be to think about what you think this accomplishes that a traditional 4 wheel mecanum drive does not.

Then draw out the wheel vectors and see if it behaves the way you think it does.

[MCeGEAR]

Well, my intent of such an odd drive train is for good traction due to surface area, and possibility to be able hold it's ground when hit. Now as far is I see it ,and bit slight mapping, it should work, but i could have very easily overlooked a large flaw.

[efoote868]

Basic physics will show that surface area has very little to do with traction.

Even if it did double your traction (which it won't), I'm not entirely convinced that the supposed benefits could outweigh the added cost, weight, and complexity of this drive-train.

If pushing power and traction are your only goals, I'd recommend a standard six wheel setup with traction wheels.

[davidthefat]

Now do you even have the budget to pull this off? Do you really think the benefits out weigh the resources needed to do this? Especially the weight would be the problem. I think it was Chris that told me not to innovate for the sake of innovation. I think that falls into that category.

[AndrewD]

Here's the picture from our team's whiteboard.

[Thxe]

This doesn't really accomplish anything. The idea that more wheels gives you better traction is a myth. The traction of an individual wheel is equal to the coefficient of friction times the downward force on the wheel. So, while going from 4 to 8 wheels will double surface area, it will also reduce the traction of each wheel by half because the weight of the robot is spread out and thus the downward force on each wheel is less.

Also, your configuration will have trouble turning due to the arrangement of the wheels. Its a bit difficult to explain, but when turning your arrangement will have some of the wheels working against each other.

Thxe

[MCeGEAR]

Let me re word what i meant to say. I wanted to find a Mecanum drive that could semi-compete with a 6 wheel drive and can strafe, this is only a 5 min concept that i want to see what people thought of.

[JewishDan18]

Might have some trouble twisting if the motors are fully linked as you indicated...

[EagleEngineer]

Why. Why would you try this what does it accomplish that the original mecanum does not accomplish?

[R1ffSurf3r]

Originally Posted by Thxe

This doesn't really accomplish anything. The idea that more wheels gives you better traction is a myth. The traction of an individual wheel is equal to the coefficient of friction times the downward force on the wheel. So, while going from 4 to 8 wheels will double surface area, it will also reduce the traction of each wheel by half because the weight of the robot is spread out and thus the downward force on each wheel is less.

While in this case you are right I wouldn't go on telling dragsters about how surface area is a myth my friend

[Ether]

Originally Posted by Thxe

Also, your configuration will have trouble turning due to the arrangement of the wheels. Its a bit difficult to explain, but when turning your arrangement will have some of the wheels working against each other.

I agree that the 6-wheel mecanum idea doesn't seem to meaningfully solve any real problem for Logomotion. But just as a pedantic point of technical interest to those who might care: If each of the six wheels were independently powered, it would be possible to compute the proper speed for each of the wheels (so they would not be fighting each other) using the inverse kinematic analysis approach detailed in this paper.

[pfreivald]

I understand what you mean to say, but I agree with the other comments:

The physics behind your idea is flawed.

To quote my absolute favorite quote: "It's a wonderful idea. But it doesn't work." (Poe's father)