Weight Distribution and Layers of GoPiGo3 ROSbot

[cyclicalobsessive]

@KeithW

I wonder if it won’t be a bit top-heavy. I’ve got my battery on the back, and that seems to work fine (and would help lower the center-of-gravity.

True, the moment for the center of mass will probably be in the battery level, with the 6 oz LIDAR and the 4 oz BeeDo character on the top.

There is delicate balance between minimizing the weight on the castor and the maximum negative acceleration (stopping forward motion or starting reverse motion).

But then it is also possible to fix a face plant:

You’ve got your distance sensor on a servo, so you’ll need a bit more clearance than I do. But you could still shorten the layer where you currently have the battery and still easily clear the distance sensor.

Also true. I was limited to the standoffs of the GPG3 Core Kit plus the extra Body Kit I purchased. The battery layer worked best with the shorter standoff, but that made the LIDAR layer huge.

The servo hits the LIDAR layer plate at +/- 70 degrees but I can live with that. I would have to trim off some of the left and right eyes to get 90 degrees, but since it is a multi-layer pc board, I don’t want to risk ruining $30.

Regardless, you’ll need an updated URDF to account for the extra height and different positioning of the sensors.

Yes, that will be a good learning task to get create the URDF for ROSbot. Looking forward to that.

[KeithW]

@cyclicalobsessive

I was limited to the standoffs of the GPG3 Core Kit plus the extra Body Kit I purchased.

Fair enough. The standoffs I used for my lidar experiment were ones I had laying around, but they were a bit skinny for actual structural use. I’d probably get some more standoffs of different heights, but that’s just me and my slight case of OCD .
/K

[jimrh]

@cyclicalobsessive

I was limited to the standoffs of the GPG3 Core Kit plus the extra Body Kit I purchased

Absolutely true.

However, I discovered that the local Chip and Dip, (electronic supply store near me), has similar standoffs in various heights, diameters, and thread pitches.

Look for a hobby shop, especially if it specializes in R/C and/or robotics, and they should have all kinds of interesting hardware.

What you did is great for a proof-of-concept model, but you may want to get more reasonably sized standoffs for The Real Deal.

Dave will thank you!