pic: New serve mk.1-2517

[kk052]

Originally Posted by CENTURION

Doesn't look like anyone has mentioned this yet, so I will. You're going to have a lot of trouble turning this module.

If I understand correctly, both wheels are locked together? When you try to rotate the module while the robot is stationary, one wheel needs to spin one way, and the other needs to spin the opposite, because the center of rotation is between them. And when the robot is moving, and you attempt to rotate the module, one wheel will have to turn faster than the other.

What you need is some sort of differential, so that when turning, the wheels are able to rotate independently, but you can still apply drive power to both.

Here's a great old video that wonderfully explains how differentials work (at least in the context of cars)

it was argued about in the design process about the use of a diff, we decided not to to save space and make the unit simpler, and the less things to go wrong the better, also if there are any ramps in the 2015 game and one side of the wheel gets on it, all the power will be given to the other wheel. we are going to have to use a lower ratio to turn it however

[asid61]

Originally Posted by kk052

it was argued about in the design process about the use of a diff, we decided not to to save space and make the unit simpler, and the less things to go wrong the better, also if there are any ramps in the 2015 game and one side of the wheel gets on it, all the power will be given to the other wheel. we are going to have to use a lower ratio to turn it however

As long as you use a beefy turning motor (not a window motor) you should be fine.

[kk052]

Originally Posted by asid61

As long as you use a beefy turning motor (not a window motor) you should be fine.

a bane bot 775 (i think) on a 132:1 ratio is what we used this year with no problems, and most likely what we will use on the prototype, if we have any issues we may use a different gearbox, or find a way through code that the wheels never pivot in place, only when the wheels move forward/backward will the assembly turn, but this is what we are prototyping to find out.

[Tyler2517]

Originally Posted by kk052

a bane bot 775 (i think) on a 1:4 ratio is what we used this year with no problems, and most likely what we will use on the prototype, if we have any issues we may use a different gearbox, or find a way through code that the wheels never pivot in place, only when the wheels move forward/backward will the assembly turn, but this is what we are prototyping to find out.

We used a 430 on a 132/1

[R.C.]

Originally Posted by Tyler2517

We used a 430 on a 132/1

A 430?

[Bryce Paputa]

Originally Posted by R.C.

A 430?

Nope I was wrong. 430 is probably a typo, there isn't a banebots 400 series as I assumed.

[Andrew Schreiber]

Originally Posted by Bryce Paputa

It's a weak, fan cooled, motor that's smaller and weaker than a rs550

That's, kinda, not on the list of approved motors?

[Tyler2517]

We used the 540.

We designed initially to use a 400 series moter with a moduler mounting plat to the gear box. Ended up using a 540.

[R.C.]

Originally Posted by Bryce Paputa

Nope I was wrong. 430 is probably a typo, there isn't a banebots 400 series as I assumed.

http://banebots.com/p/M3-RS395-12

Might be this guy, I believe it was legal at some point in time. But with the current motor allocations teams should just use the 550 or the 775.