18-12-2015 23:44

billbo911

pic: Robo Riot 3418 practice robot

It looks like you just need a belly pan and it is good to go!

Specs please.
Transmission used and ratio.
Drive formula (if not standard Kiwi).
Gyro?
Weight?

This looks like a well conceived design, I'm sure it you have learned a lot just by building it.

18-12-2015 23:45

bkahl

Re: pic: Robo Riot 3418 practice robot

Looks to me like there's a Lexan bellypan.

19-12-2015 00:39

billbo911

Re: pic: Robo Riot 3418 practice robot

Now that I look at an expanded image, I believe you are correct. Either that or they have discovered the secrets of levitation!

19-12-2015 03:17

GeeTwo

Re: pic: Robo Riot 3418 practice robot

Other than as a control board, is a belly pan really needed on an essentially triangular robot?

19-12-2015 19:21

lark95

Re: pic: Robo Riot 3418 practice robot

We used the Andymark bane bot gearboxes for CIMs, 16:1 gear ratio. The frame with gearboxes and motors weighs 24 pound even. The mane frame is 1/8th wall 1 by 2 aluminum. We used 3/16 aluminum/steel rivets. Each side is 24.5 inches long.

19-12-2015 19:23

lark95

Re: pic: Robo Riot 3418 practice robot

No, the belly pan is not needed for strength at all. We just use it to mount all of the electronics to. Everything is directly threaded to the lexan making it very easy to remove components.

We used 1/4 inch lexan with 4 10/32 screws on each side threaded directly to the frame rails. I am thinking that the side with the battery might be be quite strong enough but we will see after some demos.

19-12-2015 20:34

Ari423

Re: pic: Robo Riot 3418 practice robot

Does putting the battery on one side make the robot drive crooked? We had problems last year on mecanum with uneven wheel loading. I imagine it would be similar if not worse on a kiwi drive.

19-12-2015 21:16

lark95

Re: pic: Robo Riot 3418 practice robot

I havent really noticed anything weird. I have notice that it does not strafe very well no matter what.

19-12-2015 21:44

Ari423

Re: pic: Robo Riot 3418 practice robot

I wonder if you saet the battery over the center of the robot and tried driving if it would strafe better. When we added ballast to the opposite side of our robot last year to shift the CoM to the center it corrected all of our strafing problems.

19-12-2015 22:38

lark95

Re: pic: Robo Riot 3418 practice robot

That certainly is possible. However at this point it would be to much trouble.
Also the only service we have driven it on is a concrete floor. I am not really sure how it will handle on carpet.

20-12-2015 08:46

GeeTwo

Re: pic: Robo Riot 3418 practice robot

Assuming that you consider the battery to be at the back (or front) of the robot, that makes sense. Most of the weight is on the two "side" wheels, which point mostly forward/back, so you can get good forces in the forward/reverse direction. When trying to go sideways, half of the force should normally be coming from the "nose" wheel, but as it is carrying little weight, it cannot generate as much force.

As these wheels will have a higher CoF on carpet, I would expect better performance, including when strafing.

20-12-2015 09:06

Ari423

Re: pic: Robo Riot 3418 practice robot

Also since it looks like when that picture was taken the radio hadn't been fully mounted, you should try to move it away from that motor. Motors can cause electrostatic interference that messes with the WiFi signal. The further away your radio is from motors, large power wires, or spinning brushes (read static-y stuff) the better signal you'll get.

20-12-2015 19:13

lark95

Re: pic: Robo Riot 3418 practice robot

We will definitely do that at some point. In future preseasons we are going to be adding something on top,maybe something like a ball shooter of some sort. Then we will be able to mount the radio farther up at out of all the noise from the electronics.