EtherCAT driver for a 6 axis robot

-i would prefer to write a small c component for the initializing sequence, with an managed passthrough of the joints amp-enable-out and error pins...

-did you survive to get proper motion without pid, are the scaling correct ?

-does this descripe that everytime estop is raised, the robot lost its homing? does the robot send continous encoder values during its "own" homing sequence? this would raise a lot of following errors.

Hi!

So, without any PID and just using the motion controller outputs

joint.0.vel-cmd => lcec.0.Meca500.vel-cmd.a1
joint.0.motor-pos-fb  <= lcec.0.Meca500.encoder.a1

I was able to jog each axis ok (with following error after a few seconds).

At power-up, the Meca500 knows the approximate angle of each of its joints, with a couple of degrees of uncertainty. To find the exact joint angles with high accuracy, each motor must make one full revolution. This motion is the essential part of a procedure called homing. During homing, all joints rotate simultaneously. Each of joints 1, 2 and 3 rotates 3.6∘, joints 4 and 5 rotate 7.2∘ each, and joint 6 rotates 12∘. Then, all joints rotate back to their initial angles. The whole sequence lasts a few seconds.


Initially (at application startup) clear both the MoveID and SetPoint fields.
setp lcec.0.Meca500.motion.move-id      0
setp lcec.0.Meca500.motion.set-point     0

To start moving the robot
setp lcec.0.Meca500.vel-command        21
setp lcec.0.Meca500.motion.set-point     1
setp lcec.0.Meca500.motion.move-id      0
lcec.0.Meca500.vel-cmd.a1 thru a6 (degree/sec as REAL float)

To stop the robot, you must reset
setp lcec.0.Meca500.motion.set-point     0

absolute encoder positions (degree as REAL float) are read from
lcec.0.Meca500.encoder.a1 thru a6

joint velocities (degree/sec as REAL float) can be read from
lcec.0.Meca500.velocity.a1 thru a6

REAL floats was made possible by this commit
github.com/sittner/linuxcnc-ethercat/pull/114

 

does the robot send continous encoder values during its "own" homing sequence? this would raise a lot of following errors.

Just checked, yes it does.

-i would prefer to write a small c component for the initializing sequence

What would the C look like for setting the following at application startup?

At what stage would you then "activate" , "robot home" and check for a sucessful home? Insert this routine to the power on button in the UI?

with an managed passthrough of the joints amp-enable-out and error pins...

I believe I may need to look at "immediate homing" for the Meca500 if the robot provides its own homing mechanisms.  Thoughts?

db1981 Are you suggesting a comp "glue" layer similar to
github.com/dbraun1981/hal-cia402/blob/main/cia402.comp