4th axis tangent to path XY

Hi,
is it possible at low level (HAL layer) move automatically 4th axis tangent to XY path?

do you have suggestions?

Thanks,
Michele

Cutting with a blade ?

This does come up now and then, here is a starting point...

www.linuxcnc.org/component/option,com_ku...imitstart,6/lang,en/

Rick G

Thanks.
I have to cut with a disk round parts, the disk orientation must be tangent to path.

In this moment i'm thinking to calculate the angle with a external python module and generate right g-code, but my final idea is to move this routine in real time tread to have this automatic.

Michele

I have attached a modified kinematics file in which the A axis value automatically changes to suit the direction of movement.

You can install this with You can then swap "trivkins" for "tangentkins" in your HAL and INI files.

It probably needs more work.

Thanks, i try to use the file.

Hi,
I compiled the file following your instructions and the kinematics move A axis automatically!

The angle was in radiant so i changed angle calculation on the file (see the attached file).



Is it possible lock and unlock the A axis runtime?
I mean, start the program normally withouth A automatically moved and activate the angle automatic movement only in some parts of the program.


In the next few days i can test the kinematics on a real machine.

Thanks.

Modified file.

Sorry.

ioiotutu wrote:

Is it possible lock and unlock the A axis runtime?
I mean, start the program normally withouth A automatically moved and activate the angle automatic movement only in some parts of the program.

Yes. You would need to create a HAL pin in the rtpi_app_main function, then link that pin to something in the HAL file (motion.spindle-on would work, but remember that you need to have S > 0 for M3 to change the value of that pin) then modify the kinematics code to act on the value of that pin.

Alternatively, instead of using a pin in HAL to change the mode, you could use a user-defined M-code and a shell script containing
How much of this needs further explanation?

Thanks,

For me It's ok to use M-codes. I build:

M151
#!/bin/bash
halcmd setp tangentkins.auto true
exit 0

M152
#!/bin/bash
halcmd setp tangentkins.auto false
exit 0

Testing this m-codes with HAL METER seems to work fine, i see the status changed but the A axis always move following XY.

I have some warnings during comp command:

root@ubuntu:/home/michele/emc2/nc_files# comp --install tangentkins.c
make -C /usr/src/linux-headers-2.6.32-122-rtai SUBDIRS=`pwd` CC=gcc V=0 -o /Module.symvers modules
make[1]: ingresso nella directory «/usr/src/linux-headers-2.6.32-122-rtai»
CC [M] /tmp/tmp8A54AP/tangentkins.o
Building modules, stage 2.
MODPOST 1 modules
WARNING: "hal_init" [/tmp/tmp8A54AP/tangentkins.ko] undefined!
WARNING: "hal_exit" [/tmp/tmp8A54AP/tangentkins.ko] undefined!
WARNING: "hal_malloc" [/tmp/tmp8A54AP/tangentkins.ko] undefined!
WARNING: "hal_pin_bit_new" [/tmp/tmp8A54AP/tangentkins.ko] undefined!
WARNING: "hal_ready" [/tmp/tmp8A54AP/tangentkins.ko] undefined!
WARNING: "rtapi_print" [/tmp/tmp8A54AP/tangentkins.ko] undefined!
CC /tmp/tmp8A54AP/tangentkins.mod.o
LD [M] /tmp/tmp8A54AP/tangentkins.ko
make[1]: uscita dalla directory «/usr/src/linux-headers-2.6.32-122-rtai»
cp tangentkins.ko /usr/realtime-2.6.32-122-rtai/modules/emc2/
root@ubuntu:/home/michele/emc2/nc_files#

what do i wrong?

Sorry but i am a newbie!