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Can Repelling Magnets Replace the Spring in a Pogo Stick?

kjmagnetics.com

61–70 of 149 posts

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#61
post #6

Seems like electromagnets could help compensate for distance by drawing more current when far apart, and less when close together. A microcontroller could essentially make the force linear like a spring. Of course, then you need wires hooked up to your pogo, and that might be scary if the microcontroller has a bug (or somehow fails) since you are now essentially hopping onto a railgun.

About as scary as my Tesla on autopilot going around a curve at 75mph. Every time I ask myself, what if there is a bug or if it turns off...

Consider not going on a modern airliner. Every commercial passenger jet since the A340 has been fly-by-wire.

(military jets have been so longer).

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#62
post #6

Seems like electromagnets could help compensate for distance by drawing more current when far apart, and less when close together. A microcontroller could essentially make the force linear like a spring. Of course, then you need wires hooked up to your pogo, and that might be scary if the microcontroller has a bug (or somehow fails) since you are now essentially hopping onto a railgun.

You could have controls in the handgrips to change the shape and amplitude of the curve.

As far as bugs go, you could clamp the output in the good old fashioned analog way (i.e. via circuitry) so the worst case is you just fall/jump off which is already the case for the sprung ones.

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#63

Earlier quoted context omitted.

A lot of science museums have a display showing how magnets and copper pipes interact. In short, because of Lenz's Law, the magnet's motion induces an opposing magnetic field in the pipe ... which suggests another possible way to make a pogo stick with the right kind of resistance curve as well as addressing the heat issue.

This means the kinetic energy is lost to heat, which is not good for a pogo stick

Yes, but there will always be some heat loss, and the magnetism is lost with heat. I’m just assuming the pogo stick will drastically fail when the magnets get hot enough.

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#64
post #61

Earlier quoted context omitted.

About as scary as my Tesla on autopilot going around a curve at 75mph. Every time I ask myself, what if there is a bug or if it turns off...

Consider not going on a modern airliner. Every commercial passenger jet since the A340 has been fly-by-wire. (military jets have been so longer).

But you have more time to react on a plane and switch to manual override. It's not like people fly with just a few meters distance to other airplanes. There's also a good distance to the only other thing you can crash into, the ground, as opposed to driving between walls or with a cliff to one side.

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#65
post #61

Earlier quoted context omitted.

About as scary as my Tesla on autopilot going around a curve at 75mph. Every time I ask myself, what if there is a bug or if it turns off...

Consider not going on a modern airliner. Every commercial passenger jet since the A340 has been fly-by-wire. (military jets have been so longer).

[deleted]

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#66
post #61

Earlier quoted context omitted.

About as scary as my Tesla on autopilot going around a curve at 75mph. Every time I ask myself, what if there is a bug or if it turns off...

Consider not going on a modern airliner. Every commercial passenger jet since the A340 has been fly-by-wire. (military jets have been so longer).

737 Looks like cables, air, and hydraulics to me.

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#67
post #6

Seems like electromagnets could help compensate for distance by drawing more current when far apart, and less when close together. A microcontroller could essentially make the force linear like a spring. Of course, then you need wires hooked up to your pogo, and that might be scary if the microcontroller has a bug (or somehow fails) since you are now essentially hopping onto a railgun.

About as scary as my Tesla on autopilot going around a curve at 75mph. Every time I ask myself, what if there is a bug or if it turns off...

I know exactly what you mean. I will admit at 20mph over the speed limit going over a poorly maintained curve on the Mass Pike I usually just disengage for a moment and then switch it back on. It can take the curve, but it doesn’t feel good to let it.

I’ve had it lose tracking on the highway. It just leaves the wheel in the last position and beeps very urgently to let you know to take over.

I find autopilot helps me become more aware and less fatigued while driving. It’s a level 2 system. There is never a question of losing engagement as an active driver like what happens with level 3 self driving.

It will keep a clearly marked lane better than I can (it’s very precise with staying in the exact middle of the lane and doesn’t cut corner like humans tend to). For stop and go traffic it’s a blessing.

It sucks at zipper merging. I’ve had to brake for merging cars more than once, even though they are visible coming into my lane on the HID. That part needs work. And I don’t really trust it to change lanes as I feel like the blind spot detection isn’t quite there either.

All said it’s pretty much the most amazing driving tech ever, and the TM3 is most definitely the most amazing driving machine I’ve ever had the pleasure of owning. Just orders of magnitude better handling than I realized was possible. Curves rated at 25mph that I used to take at 45mph in my Infiniti previously with some tire squeal, it can silently tear through at 65mph. I don’t know what the skidpad rating is, but it feels unflappable and body roll is just nonexistent.

Actually it’s a bit tricky because you literally feel no complaints or judder or roll all the way up to pulling 100% of traction the tires have to offer. It is quite well mannered once it does start drifting though.

Sorry, sorry, I can’t help it. You can guess I’m thrilling at parties.

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#68
post #5

Loved the video. Didn't love the loud beep near the end, that's at about 3x the volume of the speaker the whole video...

YouTube desperately needs an audio compressor feature. Can't imagine why they haven't implemented that yet, it's more or less trivial.

Re: Can Repelling Magnets Replace the Spring in a Pogo Stick?

#69

Earlier quoted context omitted.

Hook's law[1] states that the force of a spring scales linearly with the distance it is stretched. [1] https://en.wikipedia.org/wiki/Hooke%27s_law

And magnets repel with an inverse cube law. So there is no simple way to replace a spring with magnets. You could "linearise" an electromagnet with distance sensors and code, but that's a bit of a Franken-Solution - not least because any delay in the closed loop could make the system unstable. In this case a couple of minutes of research - or maybe asking a physicist - would have saved a lot of essentially rather poi…

You coukd linearize it using a meta-material of small magnets, though it would probably end up being a cylinder lined with magnets of varying density.
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