Scrub friction

[GeeTwo]

For a 12x18" robot going to six wheels would be awful tight unless you went smaller than 4" wheels. I would recommend changing the two at the radio end to 4" omnis to minimize the scrub force resisting rotation, and to maximize the scrub force in resisting strafing motion, especially if it is applied near the CoG.

You may have some swaying motion when you go to two omni wheels, whichever end you put them on. You will probably have more swaying one direction than the other - experiment with this to determine which end should be the preferred "front". As I recall from our Ultimate Ascent 'bot, we did better to push from the solid wheels towards the omnis, but we were not driving the omnis, so YMMV.

I'm curious - you referred to this as a tote 'bot. How are you going to secure the tote to the chassis? One big hole or four little ones?

[Mschmeh144]

Originally Posted by GeeTwo

For a 12x18" robot going to six wheels would be awful tight unless you went smaller than 4" wheels. I would recommend changing the two at the radio end to 4" omnis to minimize the scrub force resisting rotation, and to maximize the scrub force in resisting strafing motion, especially if it is applied near the CoG.

You may have some swaying motion when you go to two omni wheels, whichever end you put them on. You will probably have more swaying one direction than the other - experiment with this to determine which end should be the preferred "front". As I recall from our Ultimate Ascent 'bot, we did better to push from the solid wheels towards the omnis, but we were not driving the omnis, so YMMV.

I'm curious - you referred to this as a tote 'bot. How are you going to secure the tote to the chassis? One big hole or four little ones?

This robot will have the tote sit on top of it, and connect to the frame of the tote using some sort of easy or quick connections,as I don't want to have to take parts off to remove the tote.there is no bottom to the tote we selected for the robot
We also added a set of omni wheels to the back of the robot. Which did give it some success. It was cruising around the lab this morning, until I floored it and reversed it too hard.
I underestimated the tourqe of the CIM motors we used. Resulting in a bent front axle. That part will be reinforced heavily to prevent damage like that ever again. Here is a photo of the front axle in its bent state