Maslow Home Maslow Community Garden Newsletter

Weight of chain causing inacuracy

I’m just curios if the weight of the chain between the sled and motors is accounted for. I’m sure that it would only cause a minor issue with the accuracy of the machine, but something to consider. The more chain that is let out, the heavier it becomes. This must be why the Maslow is less accurate in the bottom corners? This could all be taken care of in software.

look for a topic ‘sources of error’, there are a lot of possible errors.

What you re noticing is what we call ‘chain sag’ and the holey triangulation
does make an estimate of it, along with ‘chain stretch’ here there is just a
smidge of space between the pin and the link in the chain (if you think about
it, 1/1000" gap here multiplied by 500 links adds up to a lot of error)

good thinking, we want people thinking like you, so I want to bring you up to
speed :slight_smile:

but the bigger cause for the error in the bottom corners is that the chains get
so close to vertical that there is not much force available from gravity to pull
into the corners. This combines with the chain sag problem in that you have the
longest amount of chain anywhere in the workspace under the least amount of
tension anywhere in the workspace, so the most sag of anywhere in the workspace

the stock calibration doesn’t account for this.

David Lang

1 Like

I was looking through these last night, not that I understand much of what they are doing, but just blown away by how much thought and effort that people have put into this.

If you use treat the maslow as a 4x4’ machine a lot of these problems simply vanish and corners are much more accurate.