Constant speed source and position control
In advanced gem based APM systems both for use and production
due to densely packed nanomachinery operating at higher frequencies (~MHz)
there needs to be a focus on avoiding high energy dissipation events.
particularly: Intercrystolecular snapping modes
The two scary events in electrical case and mechanical analogy
In electrical systems these high energy dissipation events correspond to the "scary events" of:
- short circuiting a capacitor causing a current excursion
- open circuiting an inductor causing a voltage excursion
=> result being high energy dissipation at best and irreversible damage at worst
In the mechanical case of our focus the analogies are:
- not holding/retaining a force (or moment) causing a speed (or angular speed) excursion
(also known as "free wheeling"; ever seen a large ships anchor chain out of control?) - suddenly stopping a speed (or angular speed) causing a force (or moment) excursion (aka: fast "crashing" and slow "crushing")
=> the result usually being just high energy dissipation as
superelasticity of crystolecules can absorb these excursions.
And extreme mechanical excitations can dissipate the energy in a high frequency ring down.
Snapping events - free wheeling than possibly followed by fast crashing
Snapping events combine both types of scary event.
– First the force or moment (from bending or vdW forces) is no longer held,
– then possibly (but not necessarily) the to-high-speeds-accelerated part slams into a wall without any gentle breakig first.
… exciting lots of complex mechanical modes to high energy
Without the slamming and thus a more smooth back and forth wiggle ring-down
eventually the same amount of energy is dissipated in the end.
Same amount of problematic heat gets generated. It just takes a little while longer.
Just a little because at the nanoscale
the space between the high energy mechanical modes
and the low energy phonon modes is small.
One basically can count one as a form of the other.
There is no clear border.
Slow crushing events
The situation here:
Starting out in an already contacted state but not stopping moving farther despite counter-forces growing to huge magnitudes.
Due to featureing superelasticity one could even say that
to some degree crystolecules even like this sort of abuse.
Very small flexures would feature such suigh high deformations and high forces.
With caveats on energetic reversibility.
Since no high frequency modes are excited here more energy can be recuperated
than in the case of high speed crashes from snaps.
That is so long things are stopped before irreversible structural damage occurs.
Still the hihg deformations potentaially
make reciprocative dissipation mechanisms a problem.
Future sdvanced densely packed nanosystems may need to avert using flexures except
when kept
– operated at low frequency
– larger in scale
– smaller in deflections
More analysis needed. Just a note for caution.
Fast crashing events
What shall I say.
If you experimentally intentionally shoot your crystolecules at something
putting in effort to so, then you probably meant it.
As for simulations, hiugh speed is actually easier.
Also it can be fun watching crystolecules ringing and their assemblies "exploding".
This can be quite misleading for building a good intuitive understanding though.
See pages:
- A better intuition for diamondoid nanomachinery than jelly
- Misleading aspects in animations of diamondoid molecular machine elements
Why constant (angular)speed rather than constant force/moment?
Since for may things like mechanical control logic
there is no real load at the end of the driven kinematic chain,
using a constant force (or constant moment) dive would not a non held force (a scary free wheeling sate).
It would also sort of correspond to not constraining the abstract 1D coordinate of the kinematic chain to the machine phase.
I.e. Constant force source on on an unheld load can be seen as leaving towards out of machine phase.
Thus constant a speed drive would be more of a default for many cases of low load crystolecule based mechanical nanosystems.
Analog to using constant current source when driving LED diodes as beyond their voltage they act like almost like electrical shorts.
Caveat
With the caveat that in the case of high load systems and a constant force/moment source can be used.
The systems resistance then arbitrarily adjusts the actual speeds/frequencies.
To save spatial part of the machine phase property.
One still can (and needs to) track the abstract coordinate motion(s).
If click count tracked as such then while
one loses the synchronicity and precision in time,
one still does not lose the information in which step of the process the current state is.
Weaker form of machine phase?
Position control (as in machine phase)
Holding a force/moment also corresponds to keeping the charge constant.
This probably can be used to extend on the helpful mechanical electrical analogies.
Defining a motion in machine phase by trajectory
– not just in space
– but in time too
is done by specifying x(t)and
by simple basic derivation v(t) = d/dx x(t)
one gets a constant speed source situation.
The electrical correspondence being: i(t) = d/dx q(t)
See main page: Tracing trajectories of component in machine phase
Given a certain fixes capacity a fixed charge means a fixed voltage U = Q/C
Given a certain fixes sping-softness a fixed position means a fixed force F = x/(1/k) = k x