<qi-bot>
[commit] Werner Almesberger: slicer/slice.h, slice.c, util.h: extract outlines of Z slices from mesh (master) http://qi-hw.com/p/cae-tools/49abc13
<qi-bot>
[commit] Werner Almesberger: slicer/slice.c (add): only output lower end of vertical walls (still needs work) (master) http://qi-hw.com/p/cae-tools/3f2c6cd
<qi-bot>
[commit] Werner Almesberger: slicer/stl.c (stl_load_file): support binary STL as well (on little-endian hosts) (master) http://qi-hw.com/p/cae-tools/c82ea10
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<wpwrak>
(giving freecad another try. but without having to suffer crappy toolpaths in return :)
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<DocScrutinizer05>
pcercuei: I tend to agree
<DocScrutinizer05>
posting commit messages to IRC is kinda abusive
<wpwrak>
naw, i like it. shows where things are happening. but it may help if very long sequences would get truncated.
<DocScrutinizer05>
by definition/netiquette of IRC, a bot shouldn't spam a channel with unsolicited info. It might be tolerable when you do this in a dedicated channel which users would join only when they are interested in that sort of automated update about "where things happen". For a channel with /topic "hardware hackers join here to discuss Ben NanoNote, atben / atusb 802.15.4 wireless, and other community driven hw projects" I'd consider such
<DocScrutinizer05>
but obviously that's pretty much up to the individual channel's policies, as set up by the channel founders
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<DocScrutinizer05>
wpwrak: wut? Argentinia building the RN40 since EIGHTY years and still not even half done? real fun!
<DocScrutinizer05>
well, Koeln dome took longer to be not finished yet ;-)
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<wpwrak>
i think you mean paved, not constructed. where are many unpaved roads in argentia. please remember that it's a big country and traffic can be fairly light in some areas :)
<wpwrak>
s/where/there/
<qi-bot>
wpwrak meant: "i think you mean paved, not constructed. there are many unpaved roads in argentia. please remember that it's a big country and traffic can be fairly light in some areas :)"
<eintopf>
wpwrak: do you have a car in argentia?
<wpwrak>
yup, and i think i've driven on RN40 (the paved part :)
* eintopf
image some linux car with a big fat linux sticker at the back
<eintopf>
maybe baking some boards on the top of the motor while driving the car ;-)
<eintopf>
wpwrak: please don't be angry.... it's just funny. Maybe you have something similar in your car and for me that's pretty cool
<wpwrak>
that looks kinda dangerous :)
<wpwrak>
naw, the only "diy" addition is a gps support
<eintopf>
:-(
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<eintopf>
I finished my implementation for controlling a inverted pendulum via matlab PID code generation (some project for my study)
<eintopf>
it's simulated in a physic engine only
<eintopf>
but I implemented a cool opengl plotter for the PID error
<eintopf>
my experience, you don't need the fancy matlab thing... but I can't say this in my course
<eintopf>
and matlab simulink code generation - I don't know if I can setup some settings for generating code for 8bit mcu. I mean the code generator need to be sure that there is no overflow, etc...
<eintopf>
somebody wants to have some x86_64 binary to see how a PID works? it's magic
<DocScrutinizer05>
thanks, I've built both analog and digital PID controllers
<DocScrutinizer05>
:-)
<eintopf>
it's magic because I have only some error value with no dimension and the PID try to get this error at 0... okay that's how a PID works
<eintopf>
but the gains, it's purely randomness
<eintopf>
DocScrutinizer05: :O analog PID controller?
<DocScrutinizer05>
sure
<eintopf>
this is fast
<DocScrutinizer05>
that's how that stuff started
<eintopf>
ah, ok.
<DocScrutinizer05>
some prolly 100 years ago
<eintopf>
do you also do some fuzzy logic?
<DocScrutinizer05>
hardly ever
<DocScrutinizer05>
I think fuzzy logic is a joke
<DocScrutinizer05>
I can do logic of arbitrary "fuzziness" in proper digital
<DocScrutinizer05>
no need for "gaaaaaanz viel 0 is ein klein bisschen 1"
<eintopf>
and for what do you use the PID?
<eintopf>
for controlling things...
<eintopf>
I mean when do you use PID and when fuzzy
<eintopf>
okay the PID error value plot looks more like a sin(x) with some damping
<eintopf>
and fuzzy looks different, then fuzzy is maybe better
<DocScrutinizer05>
when it looks too much like sin(x) you should adjust the integral factor
<eintopf>
ah, an expert
<eintopf>
I have a little input box where I can change the values on the fly
<DocScrutinizer05>
PID regulators are used literally everywhere
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<DocScrutinizer05>
there is math to calibrate the PID from known parameters of the controlled system, but they are tedious and it's generally easier to simply adjust the stuff live
<DocScrutinizer05>
particularly since it's quite difficult to acquire a comprehensive set of parameters of the controlled system, incl all actors and sensors
<eintopf>
yes, matlab has also some feature to auto-detect the gains
<eintopf>
but then I need to have my physical model inside matlab
<eintopf>
and my physic engine only understand setMotorSpeed(500)
<eintopf>
don't know what 500 means :-)
<DocScrutinizer05>
hehe
<eintopf>
this will cost much time
<eintopf>
but for the PID this doesn't matter
<eintopf>
he only tries to get the error value -> 0
<DocScrutinizer05>
yep
<DocScrutinizer05>
it's more about inertia and momentum, about delays etc in your system
<DocScrutinizer05>
phase shift
<DocScrutinizer05>
and those are hard to measure, for any physical object
<DocScrutinizer05>
basically you compensate delay with the D component and inertia with the I component
<DocScrutinizer05>
funny even the letters match :-D
<DocScrutinizer05>
just noticed first time
<DocScrutinizer05>
you can also think of differential component as highpass and integral component as lowpass
<eintopf>
I used the normal PID controller from wikipedia
<eintopf>
pure simple
<eintopf>
with the matlab componentes Integral 1/s and derivate
<eintopf>
and sum function at end
<eintopf>
the P gain is only to set my "setMotorSpeed" to some value which fits
<eintopf>
not too fast, not too slow
<eintopf>
and I simple experiment with all values
<eintopf>
I know the matlab builtin PID controller has some filter
<eintopf>
but I didn't understand that, if I set the filter coefficient above 0, nothing worked anymore
<eintopf>
I simple have a "normal" deivate block after D-Gain
<eintopf>
don't know what matlab tries to do there
<DocScrutinizer05>
well, they build a differentiator from an integrator
<DocScrutinizer05>
a highpass for x is what you get from x-lowpass(x)
<DocScrutinizer05>
in simple analog this would be a capacitor feeding back opamp output to negative input
<DocScrutinizer05>
ooops sorry, nope, the contrary
<DocScrutinizer05>
this would be a capacitor shorting high frequencies of the feedback to ground, in negative input
<DocScrutinizer05>
the 1/s feeding back low frequencies to the inverting input, thus attenuating them
<eintopf>
ah
<DocScrutinizer05>
and such feedback however can't reduce the amplification to <1
<eintopf>
I know lowpass filter. A rc-circuit.
<DocScrutinizer05>
:nod:
<eintopf>
oh
<eintopf>
When I started my study I had some frequency generator and making serval RC-circuits. Then I looked at oscilloscope what happens
<eintopf>
the first time where I understand for what's good for
<DocScrutinizer05>
ypur amplification in such feedback filter needs to be >1 to produce any significant difference in output signal between filtered and non-filtered frequencies
<DocScrutinizer05>
quite possibly a feed-forward filter would be better suited for that usecase than a feedback filter
<DocScrutinizer05>
a filter without feedback could result in output amplitude approaching zero for frequency approaching zero
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<eintopf>
I think I don't do any filtering now, but thanks for the info
<eintopf>
I also saw some filtering about position and the acceleration, which is calculated by position''. They had some weights with pos_filter = (pos_avg * 0.1) + (real_pos * 0,9);
<eintopf>
ah so I don't have higher frequency, this will reduce some wobble pendulum :-)
<DocScrutinizer05>
maybe it helps to think about you following another car with your car on the highway. You have a very accurate way to detect the distance to the car you're following and your goal is to keep a certain constant distance
<DocScrutinizer05>
consider what you would do to the trottle when you notice your distance is 10% too short.
<DocScrutinizer05>
you also would act differnt based on your observation if that distance is short but constant or the car before you is actually slower than you
<DocScrutinizer05>
that's the D component
<DocScrutinizer05>
to adjust your speed to the other car quickly
<DocScrutinizer05>
when you notice you're 10% short but same speed, you slowly reduce throttle gradually. That's the I component
<eintopf>
ahhh
<DocScrutinizer05>
too much I without any D would result in oscillation
<DocScrutinizer05>
but too high D would also result in oscillation
<DocScrutinizer05>
both of them too low would result in your distance never getting right
<DocScrutinizer05>
the P component is basically just to adjust the target distance you want to keep
<DocScrutinizer05>
sorry when there's anything incorrect in all this, it's what I recall from my experience with PID which is quite several years ago already
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<DocScrutinizer05>
also note there are serial PID as well. What you shown is a parallel PID
<DocScrutinizer05>
actually nope, P component is what determines the working point and thus characteristics of the whole regulator. (over-damped vs overshooting)