Let's Make Robots!

tractor-trailer coupling with power transfer

This is an idea for two (or more) cooperative robots. One passive bot (with wheels, but without motors) and one active bot (with motors). The motor-bot (the tractor) would pull the lame bot (the trailer). The trailer has a power source on board. The tractor wants to recharge its battery from that source.

The big idea is so big, I won't even mention it here. Yet.

One of the necessary and mission-critical components would be the coupling of the two machines. In my design I want this coupling to be strong enough for the pulling AND I also want the two bots to share electrical power through the coupling. The mechanism must be robust and reliable. I want the tractor to be able to perform the entire coupling maneuver without my help. And also the de-coupling. So the coupling must also be fool proof.

Look at these designs made in a rapid prototyping material called pizza box.


That was the initial flat version. The red/black markings indicate where I would place conductive materials (e.g. copper plating). All the rest is electrically insulating (wood, plastic, chewing gum).

I recreated the "mushroom" in a taller version, so I could actually test the coupling/decoupling.



Here is how they "work".




And here you see how well the coupling works (even I were surprised) when the approach is not perfectly aligned.



Feel free to use these designs, even when I do not. Also feel free to post your results on LMR!



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Who said blog-postings where not read?
More blogs ought to be written though!
i think you should use the wires as Nicola has shown. Else: what will happen when the tractor brakes and the trail goes forward, thus disconnecting from the contacts on the "mushroom"?

That's very cool, I think I'll be making use of that coupling at some point. I really like the ideas you have for projects too, very creative. I hope to eventually see all of them posted here :)


I'm not sure we get to live that long Dan!

It's nice dreaming though.

Shiz man. That whole post was a thats what she said.However, that is an ingenious idea and i would love to see that in action (TWSS).


twis week?

That's pretty innovative Rik,

I like it, but I just have to ask a question.  How would you deal with the "loose" electrical connection when the coupler is slack, or just not under tension? Like when backing up, or coasting?

Duane S

Wilson, North Carolina  USA

The final implementation will have to provide some extra tension. Maybe a spring from bot to bot. Or in this case, from the pivotpoint on the traailer to the mushroom on the tractor. The whole idea  is based on the desire to keep the tractor part as simple as possible. So the spring would be attached to the trailer side.

idea for power contacts:

you could have two wire coming from both side, and having a small magnet so that when the joint close, the magnets will attach and keep the wires connected.

Here's a representation made with my Advanced Mechanical CAD Software:


The magnets should be weak enought to be easily separated when the robots disconnects.

Btw, your system looks great, is it original or you based on something you've seen around ? Maybe it's worth a patent :)