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

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.
 

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..

Peter_Cassar wrote:

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

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.

Maybe I am missing out but I only know the xyzac and xyzbc ones… please give reference where you found the xyzab - thanks.