My IQ DR6B Mimic won't lift... What magic must I do?

My IQ DR6B Mimic won’t lift… What magic must I do? (There’s only one RMS forum channel and it’s under EDR…)

The program tries to lift with 100 power right from the start and it just sags down a bit.

I tried two motors and that doesn’t work. I can change the 2x beams for 1x beams, but I want to know that would make a difference before I go for it. Anyone have experience with this?

https://www.robotmesh.com/studio/5d0ea54377215f49ee3c49a9

Is it banded?
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I don’t see rubber bands available in the Mimic. Also, when I put two motors on it I got very bizarre results.

Oh wait I’m dumb, this is a mimic not an actual lift

didn’t really look for anything wrong, but when I tried to run the lift motor the lift sort of folded backwards and kind of bugged out. I’d check to make sure everything is all build properly

I went through a few iterations. Mimic physics is not the same as real physics. If you just click run it doesn’t do much but it stays together and everything send to flow well enough. Once it hits the bottom bizarre things happen.

Maybe it behaves differently on different computers as well… Not sure.

Mimics live on a high gravity planet. IQ is not nearly as bad as EDR either. You can get it to work by adding another motor to the lift, and then replacing many of the 2x beams with 1x .
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Another annoying issue is that the motor polarity doesn’t always work the way you would expect it to. You should only have to reverse the polarity on one side, but I had to switch both.

Here is a link to the updated project: https://www.robotmesh.com/studio/5d10089d77215f49ee3c4b35

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Does the Dr6b lift straight up and down, similar to the DR4B? Or does it lift only parallel like the classic parallel arm? From my logic an arm with 6 bars wouldn’t lift straight up and down.

As long as the geometry of both six-bars is the same, and they are aligned properly, the arm will lift straight up and down.

You are right that each individual 6-bar does not lift straight up and down. But because the two 6-bars are in phase with each other but pointing in opposite directions, the non-linear motion effectively cancels out, and as a result the end of the lift moves straight up and down.

(yes, I realize that explanation is a bit hand-wavey, but my goal in this case is to build intuition, not be 100% mathematically rigorous)

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the way all dr4b’s and dr6b’s lift straight up, is that the horizontal movement of the first stage is cancelled out by the opposite horizontal movement in the second stage.

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Yes, but doesn’t the third bar of the DR6B cancel the opposite horizontal movement?

Never mind, I thought about it

I didn’t think when first mentioning this topic I’m sorry.

no worries, that’s what we’re here for.

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