Agree with all that. But its friction solved under no load conditions.
What about stiction? What about a loaded system? What about the effects of time on a loaded bearing?
I think we’re all agreed we can make some wonderfully free systems that move easily under ideal conditions. But a flexure can be so sensitive it doesn’t just wobble in the wind, it wobbles as you walk past. Always and forever. Not that that matters either, really, but does illustrate the non-existence of friction. Zip, Zilch. Nowt.
So while its true, as Mark insists, that a flexure must always impose ‘some force’ even if vanishingly small, it is also true that any bearing has friction, and much more seriously, will have stiction, and that in time and under load the stiction that it intrinsic to the system is both indeterminate and very likely to be many times larger than that of a flexure.
The fundamental problem with stiction is the unknown bit. Basically we build it as best we can and hope for the best. A flexure on the other hand can be designed and built to perform in a determined way.
Anyway, all of this is a digression. This thread wasn’t intended to argue for flexures v bearings. That is to miss the point. In this thread the fundamental benefits and characteristics of a flexure are a given, and we are looking at the PLOP derivative design described in the OP for practical accessible ways to implement that design and similar structures.
Edited by Oberon, 21 December 2019 - 06:44 PM.