Many thanks. I'll give it a try.

ah i get it...i think..

this means... its important that if i jog in +.. the + the direction is of the joint i move... and this is the direction of the arrows +.

this means for the alphas from the drawing: 0,90,90,0,-90,0 would be tool to the table?!

my setup is alpha 0,90,0,90,-90,90

i throwed again my hand with the right hand rule.. thumb up is Z..
i get 0,90,0,90,-90,90 BUT the toolplate is parallel to the base/table. different is that the toolplate is in another angle?!

its so complex...

thank you for your help....

Routerworks wrote:

Any suggestions?
 

camotics.org/gcode.html

I have tried a few online g code viewers.  None of them seem great.  Actually the best and most accurate one is the one that comes with Linuxcnc.  However I would like to view my g code on my windows computer where my CAD and other software are locaated.  I have been using NC Viewer but it won't slow down g83 g code or show the pecking steps.  
Any suggestions?

Thanks in advance.

i got some datasheets... interesting part:


i the joint angle view.... the arm is upside down?!
the arrows and signs show the alpha for each joint?! or i am wrong.. then is my DH parameter list complete wrong...

in the drawing with the measurements... the arm is in the NEST position... dont care.. but all measurements are present... now.. i wonder because:

joint 1 is the base which rotate left and right              alpha 0
joint 2 is the upper arm on the shoulder                     alpha+
joint 3 is the lower arm on the elbow                          alpha+
joint 4 wrist rotate                                                        alpha 0
joint 5 wrist roll                                                            alpha +
joint 6 toolplate rotate                                                 alpha 0


we have a side offset from shoulder rotation point to base rotation point..
we have a side offset from upper arm to lower arm...

but i was thinking that the side offset ist from base turn point to middle upper arm..... complete wrong?!

thanks guys!

 

It does sound like the issue is EMI causing miss-counts.

Software read encoder counters are more susceptible to noise
because they do no have a high enough sampling rate to allow
oversampling/ filtering of the A/B/Z signals. This means  that very
short noise pulses on the inputs can result in a miss-count

Possible fixes:

1. Use differential signaling on the A/B/Z  signals and a differential --> single ended converter
to convert the differential signals to the single ended parallel port signals.

2. Use some RC filtering of the A/B/Z signals at the parallel port end of the wiring.

For velocity mode servos (of any kind) one limitation is that the drive effectively does
linear interpolation between waypoints, so  you get what I would call a chord error
which depends on acceleration and servo thread rate.

For typical machine tool accelerations and  and say 1 KHz thread rates, this error is quite small
but machines that have high accelerations and need high precision may require either higher servo
thread rates or using second degree interpolation in the drive.


Chord error polygon vs circle =
R (1-cos(180/N))

R = radius
N = sides

R = Minimum Radius= V^2/A
N  = Sides = T_Circle/T_Sample

 

Hello,I am trying to configure M19 spindle orientation on LinuxCNC 2.9.4 using the standard orient component.My spindle is driven by an analog servo drive (0–10 V speed command) and direction is selected by a relay (CW/CCW). Because of this hardware, the PID output is converted to an absolute value and the direction is handled separately. The orientation itself works surprisingly well, but I have a strange drift that I cannot explain.Hardware

• LinuxCNC 2.9.4C10 breakout boardParallel portAnalog servo drive (0–10 V speed reference)External incremental encoder (100 PPR, TTL, A/B/Z)Encoder position-scale = 400 (quadrature)
  Code:

  encoder.0.position
  increases by exactly 1.0 per spindle revolution

HAL architectureThe orientation chain is:

• Code:

  orient
  Code:

  pid
  Code:

  mux2
  PID output →
  Code:

  abs
  Sign handled separately by logic (
  Code:

  and2
  ,
  Code:

  or2
  ,
  Code:

  not
  ) driving the CW/CCW relay.

The relevant HAL section is attached below.What works

• M3 and M4 work correctly.Rigid tapping (G33.1) works correctly.M19 works mechanically.

The problemBetween different executions of the same G-code program, the spindle zero slowly drifts.1–2 degreesAdditional observationsAfter M19:

• Code:

  orient.0.is-oriented
  is always FALSE.
  Code:

  spindle.0.is-oriented
  is also always FALSE.
  Code:

  orient.0.poserr
  is typically around 73 degrees.
  Code:

  orient.0.tolerance = 0.5
  Visually, however, the spindle is correctly oriented.

Signal values:

• Code:

  encoder.0.position = spindle.0.revs = orient.0.position
  Position is in revolutions (1.0 per revolution).

Another observationWhile debugging I discovered something unexpected.With the servo drive powered ON (motor stopped), the external encoder produces random A/B/Z pulses.The encoder is even removed from the motor and rotated by hand.If the servo drive is powered OFF, the encoder signals become perfectly clean.This may be a separate EMC issue, but I do not know whether it could also explain the orientation drift.QuestionHas anyone seen a similar behaviour with the component?In particular:

• should
  Code:

  orient.0.is-oriented
  become TRUE after a successful M19?is a
  Code:

  poserr
  of about 73° compatible with a visually correct orientation?could the drifting reference be caused by the encoder/EMC issue, or is there something wrong in my HAL logic?

Any suggestions would be greatly appreciated.I can provide the HAL file if necessary.Thank you.jelost

You mean this position? 

I was thinking it was only to show dimension?!

Thanks very much for your knowledge and advice rodw!

I'm taking it to heart and will NOT update for now.

I'm going to continue posting progress and I hope you'll find it entertaining rather than laughable!