Am I killing servos?

Questions & Help
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1

So if you’ve spotted my first build attempt in the other thread, I’m working on “Warlord” my ant weight flipper.

IMG_7266
IMG_72661920×1440 175 KB

She’s working OK, but I’m using the plastic servo from BBB and she’s not lifting as well as she could, so I ordered “The Metal One”.

Whilst waiting for it to arrive, I’m playing around with what I have, I try to lift something too heavy, it makes a weird noise and the servo becomes a bit… broken. Not responding, or moving slow. I figure I’ve pushed it too far and something went pop. Oops.

So “The Metal One” arrives and it’s all great. I get her installed and I’m throwing some test weights around, she’s self-righting, awesome.

Then randomly I flip a test chassis, about 50g, and the flipper won’t lower. Check the wires, everything is still good, nothing is crossing over to create a short, it’s driving, but no flipper. It’s a little warm, but I’d expect that as it’s been working.

I touch the hinge mechanism and the flipper shuts, and opens, then won’t close again. I rest it a bit and it works, but then stops again, either open or closed. It’s making a whirring noise like it’s trying to move even when I’m not asking it to.

Any ideas if I’m blowing servos or what’s going on? Faulty servo? Asking too much of it?

7.4v 250mAh “Giant Power” LiPo

BBB ESC

N10s

All wired up exactly like this:

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Innards picture (Flipper at max extension, ~65*):

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image1920×2560 447 KB

Please help. On a budget and can’t keep killing servos

2

Have you done any end point adjustment or travel limiting?

It’s a really rare thing to have the travel of your servo fully in sync with your flipper linkage. Normally it will need adjusting so it starts/finishes in a happy place.

If you’re getting buzzing whiring when the robot is sitting still it’s normally a sign that your servo is pushing against something immovable (like chassis) so it’s almost constantly stalled out.

3

It’s limited so that it can only open to 65% as beyond the flipper starts to lower.

I think you’re right. The start point of the horn is slightly lower than parallel to the body of the servo, and I didn’t spot that it’s touching the bottom of the chassis, less than a mm, so it’s constantly stalling at rest. Damn.