Note: Please refrain from jokes about sex, I'd like some serious answers if possible...

For my project I'm looking at designing a simple electromechanical interface for charging batteries. Specifically to have an autonomous robot be able to drive into something, have a way to align itself, and be able to charge.

Now the simplest way I have thought of is to grab a chunk of PCB and use it like a credit card slot. Then have the little sprung battery sliding contact thingo's (as can be seen in sim card slots, phone battery slots, etc...) inside to make contact.

Where I am a bit lost here is where to start with the physics of this. I have a feeling that the kero's might be able to steer me in the right direction.

I plan on designing so that horizontal misalignment can be ignored (say within 30 degrees). I know the maximum height misalignment that can occur. What I envisage is the requirement of one or two teardrop shaped curves to be able to align the PCB and the final sliding parallel.

Where do I start to look for these curves? I'm thinking that they will probably be an e^(x) or ln(x) from intuition...

Will try to do a quick cad of what I think it should look like, but what I'm after is how to make maths proofs or if they already exist...

Cheers,
Mike
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They say that he crossed the fine line, from insanity to genius.

I've just done a literal "back of an envelope sketch" and am scanning it thru now...



On the left is the fixed interface with PCB board to be used as a "plug". Need to determine the tension in the springs to allow the PCB movement as shown in the middle.

Middle being the sequence of how I envisage the mechanism to work, with the location of the forces that will be applied.

And on the right there is "Mr Robot Man" (the socket... Perhaps should have been a *Mrs. Robot Lady* as it is the "female" part of the connector), who will be driving along a line until (s)he runs into the housing of the fixed interface on the left.

So... looking for ideas on where to start with:
1. the tensions in the springs
2. the curve shape of the socket
3. the things I have missed or gotten wrong
4. and where do I even start with this?

As stated above:
1. I know the max height mis-match
2. I guess I know the PCB thickness
3. hence would also know the final dimensions of the sliding contact assembly
4. I have charts for the shape and force for the sliding contacts (if I can design it that far)
5. could probably find the strength of fibreglass PCB

Where to from here?
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They say that he crossed the fine line, from insanity to genius.

if you want a male/female socket why not use an audio jack?

For battery charging, the "way forward" seems to be induction, they seem to be getting fairly efficient these days with that in mobile phones etc.
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Mechanical engineers build weapons, civil engineers build targets

That's all way too complex - a viable commercial robot charger needs to be simple and cheap. I have a Jap copy of the Roomba vacuum robot; it just has two large contacts on the bottom and a base station with two small spring-loaded pins. There are no fancy alignment devices, the docking procedure is all done in software, which is cheaper and smarter. When the bot wants to dock, it drives about until it intercepts a narrow IR beam from the docking station. It then turns into the beam path and drives onto the docking station. If there is a contact problem it can jiggle around on the base station until it gets a charge. The bot has several sensors around the rim; I'm guessing its using a PID algorithm to accurately steer down the beam and dock.

I was going to suggest to do it like a dodgem car.
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https://www.halfdonethings.com/