5axiskins and W axis
13 Aug 2013 17:23 #37614
by eslavko
5axiskins and W axis was created by eslavko
Hello...
I'm little confused about W axis in XYYBC machine.
Ok I understand that with -W I can drill in any plane based by BC head.
But how to proper configure it? As there is no stepper for that axis?
As I see I must have XYZBCW axis enabled in ini. But for XYZBC there are some motors and config data for them. But not for W. So what I must configure for W?
I'm little confused about W axis in XYYBC machine.
Ok I understand that with -W I can drill in any plane based by BC head.
But how to proper configure it? As there is no stepper for that axis?
As I see I must have XYZBCW axis enabled in ini. But for XYZBC there are some motors and config data for them. But not for W. So what I must configure for W?
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13 Aug 2013 19:31 #37621
by andypugh
I don't think you need to configure anything physical. Any change in W position results in movements in X Y and Z motors.
Replied by andypugh on topic 5axiskins and W axis
As I see I must have XYZBCW axis enabled in ini. But for XYZBC there are some motors and config data for them. But not for W. So what I must configure for W?
I don't think you need to configure anything physical. Any change in W position results in movements in X Y and Z motors.
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- Todd Zuercher
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14 Aug 2013 09:58 #37644
by Todd Zuercher
Replied by Todd Zuercher on topic 5axiskins and W axis
Here is an example configuration with a W axis.
linuxcnc.org/media/kunena/attachments/3190/Digital_4w.ini
linuxcnc.org/media/kunena/attachments/3190/Digital_4w.hal
It is a servo config with XYZW axis.
linuxcnc.org/media/kunena/attachments/3190/Digital_4w.ini
linuxcnc.org/media/kunena/attachments/3190/Digital_4w.hal
It is a servo config with XYZW axis.
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14 Aug 2013 13:24 #37645
by eslavko
Replied by eslavko on topic 5axiskins and W axis
Todd, there is difference.
You have real hardware for W axis.
I do not. Seems that W axis in 5 axis machine is just workaround to have tool offset ?!?
So W axis hardvare is "mythical". It must be configured in INI, bot then lost somewhere in HAL.
I don't get it yet where.
So if I ommit it in hal then thing work until I do move in W axis (to accomplish tool length) but then got joint folowing error for that axis.
That's strange. I need to dig little more to got solution.
(I copy some part's from 5axis sim hal but without success yet)
Saddly there are near nill documentation about 5 axis. Even in kins help there is no 5axiskins....
But I'm happy as at least thing work as regular 5 axis machine with trivkins. As I really don't have CAM yet I can do little wait.
As I understand in some CAM programs the complete kinematics of machine is simulated (tool length, pivot lenght, some offsets...) And in other the machine should have all that thing (so I need to setup 5axiskins properly)
You have real hardware for W axis.
I do not. Seems that W axis in 5 axis machine is just workaround to have tool offset ?!?
So W axis hardvare is "mythical". It must be configured in INI, bot then lost somewhere in HAL.
I don't get it yet where.
So if I ommit it in hal then thing work until I do move in W axis (to accomplish tool length) but then got joint folowing error for that axis.
That's strange. I need to dig little more to got solution.
(I copy some part's from 5axis sim hal but without success yet)
Saddly there are near nill documentation about 5 axis. Even in kins help there is no 5axiskins....
But I'm happy as at least thing work as regular 5 axis machine with trivkins. As I really don't have CAM yet I can do little wait.
As I understand in some CAM programs the complete kinematics of machine is simulated (tool length, pivot lenght, some offsets...) And in other the machine should have all that thing (so I need to setup 5axiskins properly)
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14 Aug 2013 16:43 #37653
by andypugh
I am very much tempted to configure my tilting-head machine as a 5-axis just for this reason. The head-tilt is entirely manual, but I can set an angle (say 45 degrees) then do a G0 B45 so set up the kinematics, and then do a feed move in W (G1 F20 W-50) and Z and will move together to drill an angled hole.
Part of the confusion is that the HAL pins are called names like "axis.0.motor-position-cmd". This is a carry-over from previous versions that could not handle kinematics. it would be far clearer if the pins were "motor.0.position-cmd" for example. In the next version of LinuxCNC (probably) the pins will be called "joint.0.motor-position-cmd" to make it more clear that they correspond to a physical actuator not a geometrical direction in space.
Which joint _number_ is giving the following error? What is probably happening is that a quirk of the geometry means that to achieve the required W-move one of the physical axes is being asked to move more quickly than it can. (this may well be due to the pivot length or tool length being zero)
pivot-length defaults to 250. That is very long indeed in inches and fairly long in mm.
Replied by andypugh on topic 5axiskins and W axis
Not entirely. In the sample config it is possible to command a move in W that results in a cooordinated change in all of X Y and Z _motor_ such that you can drill angled holes.I do not. Seems that W axis in 5 axis machine is just workaround to have tool offset ?!?
I am very much tempted to configure my tilting-head machine as a 5-axis just for this reason. The head-tilt is entirely manual, but I can set an angle (say 45 degrees) then do a G0 B45 so set up the kinematics, and then do a feed move in W (G1 F20 W-50) and Z and will move together to drill an angled hole.
W exists in the G-code. The 5axiskins then outputs joint position commands on the HAL pins corresponding to joints 0, 1, 2, 3, 4.So W axis hardvare is "mythical". It must be configured in INI, bot then lost somewhere in HAL.
Part of the confusion is that the HAL pins are called names like "axis.0.motor-position-cmd". This is a carry-over from previous versions that could not handle kinematics. it would be far clearer if the pins were "motor.0.position-cmd" for example. In the next version of LinuxCNC (probably) the pins will be called "joint.0.motor-position-cmd" to make it more clear that they correspond to a physical actuator not a geometrical direction in space.
There is no way to get a following error in axis "W". Following error is a motor/joint problem, and they are referred to numerically.So if I ommit it in hal then thing work until I do move in W axis (to accomplish tool length) but then got joint folowing error for that axis.
Which joint _number_ is giving the following error? What is probably happening is that a quirk of the geometry means that to achieve the required W-move one of the physical axes is being asked to move more quickly than it can. (this may well be due to the pivot length or tool length being zero)
pivot-length defaults to 250. That is very long indeed in inches and fairly long in mm.
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14 Aug 2013 17:09 #37655
by eslavko
Replied by eslavko on topic 5axiskins and W axis
As I understand after tool change I need to command sonmething like G0W0 to mahe machine to move at right position so the tip of tool is really axis of rotation. Ok it's can be used for peck drilling too but that is not my interest (yet).
I know that W exists and can really move the joint 012 45 (andy type 01234) or in my case XYZ BC if I use trivkins.
About HAL names I know that axis.0.,,... is talking about motor/joint. So no confussion there.
Now the funny part I got folowing error on joint 8! But there are nothing about joint 9 in HAL. (Sadly I deleted that and start from scratch again so I can't post it)
So if I have axis XYZ BC W expressed as joint 012 45 8, I know what I need to define for 0-5 (X..C) but for axis W (joint 8) there is no hardware, so I can't just copy Z axis (joint 2) parameters within hal. I'm confused what I need to have and what not. More and less I do change/try to see result, as lack of documentation. For next try I was thinking to make joint 8 same as joint 2 just without connection to 7i43. I was thinking as I didn't interconnect position command with command feedback I got folowing error.
BC head isn't finished yet but pivot length of 250mm is close to real. (machine is metric)
Just need more trying to learn new stuff.
..and to check what posprocessor really need. (As far I see I can pass with trivkins, but to write some simple code by hand the 5axiskins seems mandatory.)
I know that W exists and can really move the joint 012 45 (andy type 01234) or in my case XYZ BC if I use trivkins.
About HAL names I know that axis.0.,,... is talking about motor/joint. So no confussion there.
Now the funny part I got folowing error on joint 8! But there are nothing about joint 9 in HAL. (Sadly I deleted that and start from scratch again so I can't post it)
So if I have axis XYZ BC W expressed as joint 012 45 8, I know what I need to define for 0-5 (X..C) but for axis W (joint 8) there is no hardware, so I can't just copy Z axis (joint 2) parameters within hal. I'm confused what I need to have and what not. More and less I do change/try to see result, as lack of documentation. For next try I was thinking to make joint 8 same as joint 2 just without connection to 7i43. I was thinking as I didn't interconnect position command with command feedback I got folowing error.
BC head isn't finished yet but pivot length of 250mm is close to real. (machine is metric)
Just need more trying to learn new stuff.
..and to check what posprocessor really need. (As far I see I can pass with trivkins, but to write some simple code by hand the 5axiskins seems mandatory.)
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14 Aug 2013 17:57 #37658
by andypugh
This is probably a config error.
How many axes are defined in the INI?
You probably want [TRAJ]AXES=6 and [TRAJ]COORDINATES = XYZBCW
Replied by andypugh on topic 5axiskins and W axis
Now the funny part I got folowing error on joint 8!
This is probably a config error.
How many axes are defined in the INI?
You probably want [TRAJ]AXES=6 and [TRAJ]COORDINATES = XYZBCW
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14 Aug 2013 18:03 #37659
by andypugh
Actually, what is probably missing is the feedback loopback defined in lines 21 to 38 here:
git.linuxcnc.org/gitweb?p=linuxcnc.git;a...b5bd5dbf01e7;hb=HEAD
That short-circuits all following error feedback in that config. You probably want to leave the "synthetic" joints looped back, but not the real ones.
A shorter format is
Replied by andypugh on topic 5axiskins and W axis
Now the funny part I got folowing error on joint 8!
This is probably a config error.
How many axes are defined in the INI?
You probably want [TRAJ]AXES=6 and [TRAJ]COORDINATES = XYZBCW
Actually, what is probably missing is the feedback loopback defined in lines 21 to 38 here:
git.linuxcnc.org/gitweb?p=linuxcnc.git;a...b5bd5dbf01e7;hb=HEAD
That short-circuits all following error feedback in that config. You probably want to leave the "synthetic" joints looped back, but not the real ones.
A shorter format is
net J8-pos axis.8.motor-pos-cmd => axis.8.motor-pos-fbPlease Log in or Create an account to join the conversation.
14 Aug 2013 18:24 - 14 Aug 2013 18:25 #37660
by eslavko
Hmm I defined AXES=9 acording manual
www.linuxcnc.org/docs/html/config/ini_co...tml#sub:TRAJ-section
Replied by eslavko on topic 5axiskins and W axis
Now the funny part I got folowing error on joint 8!
This is probably a config error.
How many axes are defined in the INI?
You probably want [TRAJ]AXES=6 and [TRAJ]COORDINATES = XYZBCW
Hmm I defined AXES=9 acording manual
www.linuxcnc.org/docs/html/config/ini_co...tml#sub:TRAJ-section
Last edit: 14 Aug 2013 18:25 by eslavko.
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14 Aug 2013 18:29 #37661
by eslavko
Yes I do not have that feedback. And all other seems now normal. When I try to move W axis I got joint folow error for joint 8 (W).
I will put that feedback and try again.
Replied by eslavko on topic 5axiskins and W axis
Actually, what is probably missing is the feedback loopback defined in lines 21 to 38 here:
git.linuxcnc.org/gitweb?p=linuxcnc.git;a...b5bd5dbf01e7;hb=HEAD
That short-circuits all following error feedback in that config. You probably want to leave the "synthetic" joints looped back, but not the real ones.
A shorter format isnet J8-pos axis.8.motor-pos-cmd => axis.8.motor-pos-fb
Yes I do not have that feedback. And all other seems now normal. When I try to move W axis I got joint folow error for joint 8 (W).
I will put that feedback and try again.
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