5 ms·
But is it linear, from the data? They had two datapoints and projected from that sparse data a regression line.
by jldugger 8y ago
But is it linear, from the data? They had two datapoints and projected from that sparse data a regression line.
- twtw 8y agoThere are far more than two data points on all of the charts in the article. What chart are you looking at?
- jldugger 8y agoThe youtube video mostly.
- mindslight 8y agoNo, it's linear from basic physics.
- mhh__ 8y agoWithin a certain operating region (stress and strain, i.e. the straight bit on the stress/strain graph), a spring will behave linearly e.g. F = kx. In real life it should be pretty close to linear, but it would be worth checking as I could imagine there being non-linearity or time dependence of a spring under what is probably a decent amount of load being applied quickly and repeatedly.
- thomasahle 8y agoYes, that would have been fair. The electromagnets are also (close to) linear if you look at small intervals.
- halestock 8y agoHook'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 https://en.wikipedia.org/wiki/Hooke%27s_law
- TheOtherHobbes 8y agoAnd 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 pointless tinkering. I mean - if you enjoy tinkering more than you enjoy producing an elegant solution, then tinker away. But this is noodling around for the sake of it, not solid engineering.
- madengr 8y agoYou 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.
- SamReidHughes 8y agoYou can also linearize it by making the displacement small enough -- which is how Hooke's law actually works.