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Hello! Today I was working on a GUI and found what the problem was! Last time I didn't do it according to the instructions. I wrote Index with a capital letter, but it should have been with a small letter. It turns out that index is case sensitive. I did this today and it worked. This is much faster than typing commands manually. Thank you!

@Grotius

Question 1:
yes s0 and se are the end points. The first clothoid of the spline P(s) starts at s0 and the last (4th) clothoid of the spline ends at se.
P_traj.(s0) = P(0) and P(s4) = P_traj.(se)
P(s) is the clothoid spline and P_traj.(s) are the curves at the beginning and end of the spline.

Question 2:
That's correct. You can either calculate first all the derivatives and transform them afterwards or you can first transform v_a1 and v_a2 and then calculate the derivatives.

Question 3:
Exactly, this is one of the boundary conditions. it is the z component of the first derivative in the starting point s_0 in the transformed coordinate system.

Question 4:
Fresnel Integrals show only up in equation 44. Until now we did not need them.

I think you are getting things confused and did steps not in the instructions. If you load firmware.bin onto the SD card the first time, it will change to firmware.cur if it loaded correctly. Your config.txt file is stored on the sdcard, it needs to remain inside the board.

if you loaded the firmware using other methods, it is possible you overwrote the bootloader in which case the firmware will not load. you might need to reinstall flash the board with bootloader, then reload the firmware.

with the stock bootloader on the octopus, all you need to do is
- put the firmware.bin on the sd card
- put config.txt on the sd card
- put sd card in octopus and leave it there
- thats it

1x Universal Stepper Controller
1x Universal PWM Controller
4x PWM Servo Amplifier
1x Spindle DAC
1x PCI-e card + cable
For specs visit: picosystems.store/shop/

 

Price: 350eur + shipping in EU (from Slovenia).
tomaz_ti1(at)hotmail.com

Alles, was ich geschrieben habe weg. (nich schön, passiert hier öfter)

Z Achse erste Anfahrt 0.03 mm danach Messuhr wieder genullt und dann bekomme ich +0.01-0.00 mm (fährt fast wieder auf 0)

Y Achse erste Anfahrt 0.02 und danach ist das immer so im Bereich +0.02-0.00 mm gelandet.

X Achse ähnlich, wie Z-Achse.+0.01-0 mm wenn die Messuhr nach der ersten Anfahrt genullt wurde.

Umkehrspiel auf der X-Achse ist 0.04 mm.

Das schockiert mich etwas, weil es viel besser als erwartet ist.

Ich habe mehrfach einfach "home all" gedrückt, so dass die Achsen aus dem Schalter fahren und sofort wieder rein.
Aber auch einige Versuche mit "Anlauf" aus 60-150 mm Entfernung habe ich gemacht. Das hatte keinen Einflusss auf die Ergebnisse.

Fazit für mich: a) "gut genug" und  b) "besser, als erwartet".

Über Hersteller, Alter, Sorte der Sensoren weiß ich nix. (gebrauchte low budget Maschine, vermutlich so um 2006-2008 )

Gruß Timo

p.s. still not convinced. ... haha.... jedenfalls muss ich da nicht ran. 
pp.s. Die Endschalter hängen am Parallelport vom Rechner, die Schrittmotoren (open loop) laufen über 6i25 mit 7i76
 

@Fiabian,

Thank you for checking this.

Question 1:
I updated the related code for eq 39. link    

Page 7, eq39.
Here the abstract states that : "s0, se are parameters at the start, end point of clothoid."

When i think about that. It's meaning or pointing to the fillet start, end point for the clothoid spline.
s0, se are in my opinion waypoints on segment 1 & 2, where the spline should start at s0, and end at se.
Can you confirm this?

Question 2:
Page 7, eq35.

Here the 2 segment transformation is done, It multiplies the segment points with the matrix T. Everything ok.

Then for the derivates is proposes to also multiply the derivates with the matrix T.
I have my questions about the workflow here.

1. We start with 2 segments in 3d space.
2. We apply transformation. The transformation uses the workflow:  eq35 -> eq33 -> eq33->eq30_theta.
3. For the transformation only one time we use eq30_theta to get the first derivate theta. Note: no cpu consuming task.
4. Transformation is done.

Given steps 1-4, only one time the first derivate is calculated. 
We did not calculate all derivates when segments where at initial 3d space position.

So eq35 to multiply all derivates by the matrix T is rendundant.
We can better calculate all the derivates when segments are in transformed position, only then we need them.

Question 3:
For the inputs of eq39.

If we look at the first line   :  Theta1.0 = asin ( ztraj ( so ) )

The first derivate theta for a point P consists out 3 values, x,y,z.
Then we used the transformed point P here.
Then for ztraj, we used the first derivate theta, the z value.

As in question 1. I think s0 & se are fillet start, end points to use here.

Question 4:
Until now, no Fresnels where required?

hi cakeslob,

I checked the firmware version (stm32F446 octopus 1.1) At some point i was using minicom and cutecom to test the spi communication, I got [42] back at some point.

I just reinstalled the firmware using CubeProgrammer. What I dont get is why config.txt with the pin mappings should go in the sd reader of the octopus board. I did a secure format of my 8 and 16 Gb sd cards from realiable brands (Kingston and Sandisk) FAT32, but I never had the firmware being renamed to firmware.cur. For this reason I believe that having the sd card in there with the config file not being read is the issue.

So I'm assuming that CubeProgrammer did a good job and the MCU is flashed correctly. However when powering the board, it takes no motor current which I thought is weird. And the linuxcnc control still stuck in estop....

Gosh what else can I try?
Thanks

p.s. maye I didnt name all things I tried but I definitely went over the checklist you provided  

Does anyone want to buy my Mesa control cards? I have a single board pc with PCI/PCIe slot I can add in for cheap.

Located in France/Norway but I will be back in the States in April so I could ship them from there as well. 

They work perfectly, I am just moving away from LinuxCNC 

100 Euro/USD + shipping

​​​​​​​Luke 

 

I checked:
setp hm2_5i25.0.encoder.00.filter 0
It doesn't change anything.
In the evening I will try to take halscop photos of what they look like.

Hi Grotius,

I guess you calculated va1 directly as the vector between centerpoint P_c and Startpoint P_a0 and va2 by first calculating n via the cross product between va1 and the vector between P_c and end of the arc P_as?
In the colinear case this will not work as the circle is not clearly defined in this situation, so it is required to get the additional info from LCNC in which plane this arc is supposed to be so your solution is the way to go.

Sorry Timo, ich hatte mich evtl. etwas missverständlich ausgedrückt.
Es ist im Vorgang der Referenzfahrt unerheblich, wenn die X-Achse ein paar Zehntel verstellt ist!
Selbstverständlich ist es sehr wichtig, dass die Referenzposition exakt und reproduzierbar angefahren werden kann.

Wie schon geschrieben, Dein Tip mit dem Messtaster war Super und das werde ich unbedingt durchführen.
Interessiert mich wirklich brennend wie die Wiederholgenauigkeit bei meiner Maschine aussieht und, wenn ja, wie groß die Steuung ist.

Wenn Du Lust hast, Deine induktiven Sensoren mal zu testen, wäre das super. 
Dann könnten wir mal eine ergebnissoffene, praktische Gegenüberstellung machen. 
Ich hatte mich ja damals auch nur aufgrund von Annahmen für die mechanischen Schalter entschieden..

Gruß Jens 

@urvilsuthar
We can change feed rate in real time but acceleration changes need a queuebuster command in the gcode like M66 E0 L0.

In my opinion it does not make the mesa cards obsolete. yes digital servos don't need the step/dir or analog interfaces of standard mesa cards. But that is not the point. In my opinion mesa cards are not used in professional of the shelf solutions anyway. So it is the hobby and semi professional market mesa is addressing.
When your controller of an old machine breaks do you replace everything? or do you replace the broken parts with new stuff. Here having the option to go with ethercad would be great.
When you build your own machine you most likely will only use a digital spindle servo and not one on all axes to keep the cost down.
When you want to add stuff for automation the ability to add steppers is huge due to the low cost. And everyone has them laying around who works with automation. I once hacked together a system which pneumatically unlocked a clamp and advanced a square profile for the next part with two rubber wheels and two steppers. Cheap and fast.

Right now my main motivation is linear encoders.