Our tread

[HaWkeYe15]

I fear that the changes we made to our wheel treads are going to slow us down at the competition.
We went to ILM recently and we drove our duplicate on the carpet there and we couldn't turn.
Does anyone know if our tread (shown below) will make us slower?

[Conor Ryan]

i've heard something before on too much traction.

But that mostly affects robot's with tank treads. What happens is the friction generated by the treads touching the carpet, and creating enough friction to stall the motors. But with wheel treads? Thats a first.

[Billfred]

Too much traction can happen on virtually any robot setup--although it mainly plagues 4WD, 6WD, and treads. Without knowing more about your robot's setup, it's really hard to say whether those wheels will leave you stuck.

[henryBsick]

More traction does not slow a robot down. It increases the power required to turn. Watch the robot when it turns... it has to slide laterally. Wheels with a high coefficient of friction don't slide easily, therefor making it harder to turn. That is why there are teams that have pop-down sliders or casters. They allow the 2 wheels of the robot still in contact with the carpet to spin in opposite directions easily turning the caster or slider. Basicly..your wheels have to much grip for your motors to turn. The motors are geared too fast...the output through your reduction doesn't have the torque requiured to overcome the lateral friction on the wheels. If you want to turn faster...get a lower friction wheel, increase the numbr of motors on you drivetrain, or reduce the gearing for an overall slower robot, but able to turn. More information is needed though, for instance how many motors are on the drivetrain, the reduction, and the wheel setup ie:4 or 6.

[HaWkeYe15]

hmmm, the carpet was pretty "fluffy" but it scares me because I'm not sure its too much different than the competition carpet, maybe I should have paid more attention to the carpets last year, hmm.
We did adjust our sensitivity on our joystick in the programming, so I guess we'll just have to mess around with that some if all else fails.
We were able to move foreward but because the x-axis programming was adjusted to about half, we could not turn from idle positions.
I guess we'll just have to play around with the programming when we get to the competition, which im so excited for!!

Originally Posted by cdr1122334455

i've heard something before on too much traction.

But that mostly affects robot's with tank treads. What happens is the friction generated by the treads touching the carpet, and creating enough friction to stall the motors. But with wheel treads? Thats a first.

[HaWkeYe15]

Here're pictures of our robot:


We have 6 WD with the gear boxes provided in the kit.

[Billfred]

If your middle wheel is down a bit (which the kitbot frame provides for), you should be good.

[sanddrag]

As for trouble with turning:

Are the center wheels lower than the rest? If so, how much? If not, they should be.

Also, you may consider changing two or four of the wheels back to just normal tread the way they come.

Last, I think the competition carpet is finer and slicker than most carpet of the same pile I've seen.

[HaWkeYe15]

Our middle wheel is down enough to see a noticeable shift of gravity when we bring a tetra from one side (approx. 30-55 degree angle) to the other side (approx. 60-85 degree angle).
Thank you for your help everyone, good luck to you all at your competitions, hope to see you at nationals if my team goes.
and if the carpet is finer than i thought it was, it should be good.

Originally Posted by sanddrag

As for trouble with turning:

Are the center wheels lower than the rest? If so, how much? If not, they should be.

Also, you may consider changing two or four of the wheels back to just normal tread the way they come.

Last, I think the competition carpet is finer and slicker than most carpet of the same pile I've seen.

[Chris Fultz]

Ideas if you stil have problems:

Make the center wheels about 1/4" lower than the outside ones.

Remove the tread from the outside wheels.


Also, a tip for later builds - you can drill several holes in those sprockets to remove weight. You can cut 20 - 30% of the weight from them and still get good performance. With 8 on the robot, it can add up to a significant weight savings.

[HaWkeYe15]

heh.. the thing was, we were scared about being UNDERweight rather than overweight this year, we used the frame that came with the kit so we had a lot less weight this year.

Originally Posted by Chris Fultz

Ideas if you stil have problems:

Make the center wheels about 1/4" lower than the outside ones.

Remove the tread from the outside wheels.


Also, a tip for later builds - you can drill several holes in those sprockets to remove weight. You can cut 20 - 30% of the weight from them and still get good performance. With 8 on the robot, it can add up to a significant weight savings.

[haverfordfords]

Originally Posted by HaWkeYe15

I fear that the changes we made to our wheel treads are going to slow us down at the competition.
We went to ILM recently and we drove our duplicate on the carpet there and we couldn't turn.
Does anyone know if our tread (shown below) will make us slower?

While this may do absolutely nothing, we had major problems with our desensitising program for the joysticks (it would make our robot ONLY go in reverse and we had no control whatsover - it ended up eating up an inch of carpet and stalling our motors, but ANYWAY...) I would reccomend just TRYING to take out the programming for the desensitizing of the joysticks and see if that works. It's worth a shot.

[HaWkeYe15]

Yeah, at first we had trouble making it less sensitive at first.. but we mastered it. We can always undo what we did.

Originally Posted by haverfordfords

While this may do absolutely nothing, we had major problems with our desensitising program for the joysticks (it would make our robot ONLY go in reverse and we had no control whatsover - it ended up eating up an inch of carpet and stalling our motors, but ANYWAY...) I would reccomend just TRYING to take out the programming for the desensitizing of the joysticks and see if that works. It's worth a shot.

[meiv4]

Originally Posted by Chris Fultz

Ideas if you stil have problems:

Make the center wheels about 1/4" lower than the outside ones.

Remove the tread from the outside wheels.


Also, a tip for later builds - you can drill several holes in those sprockets to remove weight. You can cut 20 - 30% of the weight from them and still get good performance. With 8 on the robot, it can add up to a significant weight savings.

watch your size when you do this. we had our center wheele 3/16 lower, and when it was resting on the front 2 wheeles it fit inside the box, but when it was on the back 2 it was outside by maybe 1/4 inch... our 15 minute solution was attaching a ziptie to the shield and placing it under the back wheel at the begining of competition.