TCP 5-axis kinematics

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23 Jan 2022 16:50 - 23 Jan 2022 17:42 #232890 by dgarrett
Replied by dgarrett on topic TCP 5-axis kinematics
> any idea how to correct this?

No -- you did not supply information about your makefile
or what you did.


However, as noted:
forum.linuxcnc.org/10-advanced-configura...ics?start=400#232231

It is recommended to use halcompile to make a custom
switchable kinematics module since:
1) in manhy cases, no additions or modifications
are required to the source tree
2) modules can be built using a deb install.
(The halcompile utility is provided in the
package linuxcnc-dev).

Attached is a minimal sim config including a comp file
(xyz_a_bc_trt_kins.comp) that uses the functions from your file:
forum.linuxcnc.org/media/kunena/attachme.../xyz_a_bc_trt_kins.c

To use:
$ tar xf example.tar
$ cd example
$ [sudo] halcompile --install xyz_a_bc_trt_kins.comp
# NOTE: sudo only need if using a deb install,
# do NOT use sudo if using RIP (run-in-place build)
$ linuxcnc example.ini

(Starts the axis gui and a halshow widget)
In axis gui:
F1 # Estop off
F2 # Machine on
Ctrl-Home # Home All
F5 # MDI tab
M429 # select kinstype=1 (halshow verifies)
M430 # select kinstype=2 (halshow verifies)
M428 # select kinstype=0 (halshow verifies)
Attachments:
Last edit: 23 Jan 2022 17:42 by dgarrett. Reason: fix bug in tarfile: missig m66 in 430remap.ngc
The following user(s) said Thank You: tommylight

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29 Jan 2022 14:33 - 29 Jan 2022 14:37 #233436 by jsskangas
Replied by jsskangas on topic TCP 5-axis kinematics
Hello

Thanks for clearing out.
I got it installed this way.

Some problems:
When you change kinematics machine makes a loud "Bang" noise.
Somehow this kinematic switching type makes sudden position change that then PID corrects.

If then press to "F3" to jog mode It makes another bang, clearly shifting to individual axis mode again as you try to move rotary axis tool does not follow.

Then back to MDI mode and when you try to set kinematic mode back It gives another loud back with a following error.

Anyone else has same type of problems?
I think this is specific problem to analog servo users.

I did not had this problem with my earlier switching kinematics, but as earlier mentioned in this thread that
it was only able to change kinematic mode when rotary axis were at 0 position.
But it did not introduce this loud bang.  
Last edit: 29 Jan 2022 14:37 by jsskangas.

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30 Jan 2022 19:56 - 30 Jan 2022 20:02 #233572 by Aciera
Replied by Aciera on topic TCP 5-axis kinematics
I run it on two mills with closed loop steppers and a robot with a digital servo interface without issues. I know there are other users of the feature and so far no reports have come back about following errors.
As user feedback has been so scant I cannot say whether you are actually the first to run it on analog servos or not.

[edit]
Are you sure your forward and inverse kinematic models match up properly?
Last edit: 30 Jan 2022 20:02 by Aciera.

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05 Feb 2022 21:48 - 05 Feb 2022 21:50 #234055 by mittim
Replied by mittim on topic TCP 5-axis kinematics
Is there a working TCP kinematics module for XYZAC? Only found XYZBC from jsskangas.
Last edit: 05 Feb 2022 21:50 by mittim.

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06 Feb 2022 08:42 #234085 by Aciera
Replied by Aciera on topic TCP 5-axis kinematics
your installation should contain a simulation config:
configs/sim/axis/vismach/5axis/table-rotary-tilting/xyzac-trt.ini

The kinematic xyzac-trt-kins.c and trtfuncs.c can be found in in
src/emc/kinematics

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14 Mar 2022 05:35 #237190 by Peter_Cassar
Replied by Peter_Cassar on topic TCP 5-axis kinematics
Hi All,   I'm scratching my head on this one...Is there are simple explanation of what's needed in the HAL file to get something like an xyzac-trt with TCP machine configured? I see a lot of posts with snippets of HAL configs , talk of success and desirable features..I've read the PDF and doc page. There are no sample HAL and INI examples. I find the SIM stuff confusing.

What is different in the HAL config between simple 5axis trivkins xyzab and proper xyzac-trt or xyzbc-trt kinetmatics ? I understand the mathematics behind it , 3D transformations , rotations and translations etc.  I understand the offsets for the vectors need to be specified somewhere, either in HAL or a file.

I have 5 axis trivkins working with a  Mesa 5125+7i76 .  If I set the kinematics to xyzab-trt  I get five joints (0 to 4)  in the Axis GUI. Where to from here?  Does LinuxCNC assume each axis pivot is co-located , there are no translations? I would like Tool Center Point functionality and would like to see the X axis translate while the A axis is tilting the B or C axis to keep the work under the tool.

I'm using the latest version of LinuxCNC 2.8.2 

Can I simply take an AXIS SIM config with xyzab-trt and modify it to work with actual hardware?

Thanks,
Peter.
 

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15 Mar 2022 08:24 #237302 by mydani
Replied by mydani on topic TCP 5-axis kinematics
I am currently trying to wrap my head around how the link/joint situation can be noted based on the work of Rudy du Preez.

In his 6DOF robot document I can follow his thoughts, however I am not sure about how to model a 5 axis machine as such with links and joints. For a robot arm it's quite obvious, one fixed base and a sequence of links and joints which lead to a given amount of transformations. With a CNC machine you also have a fixed base of course, but then there's one path of links and joints, in my case for X,Y,Z,B and another for A.

Not quite sure how Denavit-Hartenberg for this setup is applied...

Not needed this kind of thinking and math for the last 20years makes me little woried..

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15 Mar 2022 08:27 #237305 by mydani
Replied by mydani on topic TCP 5-axis kinematics

I have 5 axis trivkins working with a  Mesa 5125+7i76 .  If I set the kinematics to xyzab-trt  I get five joints (0 to 4)  in the Axis GUI. Where to from here?  
 


 
For xyzab there is no kinematics for TCP available atm. This is the reference for my post above.

Regards,
Daniel

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15 Mar 2022 21:11 #237380 by Peter_Cassar
Replied by Peter_Cassar on topic TCP 5-axis kinematics
OK then what's the purpose of xyzab-trt and to xyzac-trt kinematics? My thinking is that the kinematics is applying transformations to the X ,Y and Z axis when AB or AC are moving.

Regards,
Peter.

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15 Mar 2022 21:19 #237382 by mydani
Replied by mydani on topic TCP 5-axis kinematics
Maybe I am missing out but I only know the xyzac and xyzbc ones… please give reference where you found the xyzab - thanks.

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