mathstodon.xyz is one of the many independent Mastodon servers you can use to participate in the fediverse.
A Mastodon instance for maths people. We have LaTeX rendering in the web interface!

Server stats:

2.7K
active users

#controltheory

0 posts0 participants0 posts today
Continued thread

You could think of a tach signal as a pulse density modulation. Each clock period is an implicit sample. If the tach is ticking at 1/200,000 the clock speed, then for 200,000 consecutive clocks, there are 0 samples, then there's a single 1 sample.

So I can run that through a low pass filter and get a very low amplitude speed signal? Are there feasible digital filters that work when the cutoff frequency is orders of magnitude below the sample rate?

DSP and control theory tooters, how do you smooth a tach signal?

I'm measuring a sequence of tachometer pulses, and I want to turn that into a smoothed current speed number. Everything I know about DSP uses a fixed sampling interval, but these aren't fixed -- the interval is the signal.

This has to be a well known problem with well known solutions...

Thank you.

ModConFlex' first researchers started around August 2023. Our presently 13 #MSCA researchers are coming from fields of #engineering, #physics and/or #mathematics. They are hosted by eight different #universities for their PhD and meet at least once a year at our annual network and training events.

Their research focuses on a range of topics from #ArtificialIntelligence over #ControlTheory (applied to floating #WindTurbines or, more theoretical, port Hamiltonian systems) to #FlexibleAircraft.

Last 2024 publication within the #ModConFlex project:

"LQR control for a system describing the interaction between a floating solid and the surrounding fluid" on #mathematics of #solid moving on the #sea and #control acting on the solid.

Co-authored by #ModConFlex #MSCA researcher Zhuo Xu and published in Mathematical Control and Related Fields:

aimsciences.org//article/doi/1

Congratulations to Zhuo for his first #publication !

#controltheory

#offshorewind
#floatingwindfarms

Mathematical Control and Related FieldsLQR control for a system describing the interaction between a floating solid and the surrounding fluidThis paper studies an infinite time horizon LQR optimal control problem for a system describing, within a linear approximation, the vertical oscillations of a floating solid, coupled with the motion of the free boundary fluid on which it floats. The fluid flow is described by a viscous version of the linearized Saint-Venant equations (shallow water regime). The major difficulty we face is that the domain occupied by the fluid is unbounded so that the system is not exponentially stable. This raises challenges in proving the wellposedness, requiring the combined use of analytic semigroup theory and an interpolation technique. The main contribution of this paper is that, in spite of the lack of exponential stabilizability, we could define a wellposed LQR problem for which a Riccati-based approach to design feedback controls can be implemented.

A couple decades ago it occurred to me that the dynamics of disagreement often tend toward polarization rather than toward unification at a higher level of understanding.

Further, it seemed (to me) that this might be analogous to the behavior of a feedback loop out of control and going to one or the other of its extreme rails.

And further, this seemed (to me) to be the behavior of a system finding its lowest energy/information state, associated with lack of requisite variety.

This behavior seemed (to me) generalizable in principle across systems based on electronics, mechanisms, …, human individuals, and groups.

At that time I was active in a forum of Very Smart People, and when I ventured this observation/opinion it received no interest or engagement.

I'm wondering whether now, twenty years later, with polarization in politics being grossly apparent, whether anyone reading this might be able to recommend some sources of more extensive thinking on the question of such a general principle…?

Better late then never: #introduction
I'm a researcher at the German Research Center for Artificial Intelligence (@DFKI) interested in #ReinforcementLearning, #ControlTheory and #Robotics. My career so far included: Selling popcorn, cabinet making, mechanical engineering, database programming, mechatronics, controller design, reinforcement learning and robotics.
Looking forward to some nice and interesting discussions on any of these topics!