[solved] Using motorless B-axis in HAL only
19 Apr 2020 11:54 - 19 Apr 2020 16:54 #164629
by Aciera
[solved] Using motorless B-axis in HAL only was created by Aciera
I'm working on a mill with a manual swivel head, an indexing b-axis without a motor. We use this with 5-axis xyzbc-kinematics to mill pockets at preset angles of the tool in reference to the table like in the image below but without the rotary table.
It's all working with the B-axis connected to a stepgen on a MESA 7i76e that does not have an actual motor connected to that particular output connector. I can command say G0 B30 and the DRO for the B-axis counts up to 30 and that is then used in the kinematic to calculate the movement of the X- and Z-axis.
So as it is the loop gets closed on the MESA board.
Now I would like to use that stepgen on the MESA board for another axis and have the b-axis working only in software.
I'm guessing I need to somehow provide the pid with a position feedback to get the DRO to function.
Does anybody have an idea if it is possible to close that loop in HAL and get the DRO to function?
It's all working with the B-axis connected to a stepgen on a MESA 7i76e that does not have an actual motor connected to that particular output connector. I can command say G0 B30 and the DRO for the B-axis counts up to 30 and that is then used in the kinematic to calculate the movement of the X- and Z-axis.
#*******************
# AXIS B
#*******************
setp pid.b.Pgain [JOINT_3]P
setp pid.b.Igain [JOINT_3]I
setp pid.b.Dgain [JOINT_3]D
setp pid.b.bias [JOINT_3]BIAS
setp pid.b.FF0 [JOINT_3]FF0
setp pid.b.FF1 [JOINT_3]FF1
setp pid.b.FF2 [JOINT_3]FF2
setp pid.b.deadband [JOINT_3]DEADBAND
setp pid.b.maxoutput [JOINT_3]MAX_OUTPUT
setp pid.b.error-previous-target true
setp pid.b.maxerror .0005
net b-index-enable <=> pid.b.index-enable
net b-enable => pid.b.enable
net b-pos-cmd => pid.b.command
net b-vel-cmd => pid.b.command-deriv
net b-pos-fb <= pid.b.feedback
net b-output => pid.b.output
# Step Gen signals/setup
setp hm2_7i76e.0.stepgen.04.dirsetup [JOINT_3]DIRSETUP
setp hm2_7i76e.0.stepgen.04.dirhold [JOINT_3]DIRHOLD
setp hm2_7i76e.0.stepgen.04.steplen [JOINT_3]STEPLEN
setp hm2_7i76e.0.stepgen.04.stepspace [JOINT_3]STEPSPACE
setp hm2_7i76e.0.stepgen.04.position-scale [JOINT_3]STEP_SCALE
setp hm2_7i76e.0.stepgen.04.step_type 0
setp hm2_7i76e.0.stepgen.04.control-type 1
setp hm2_7i76e.0.stepgen.04.maxaccel [JOINT_3]STEPGEN_MAXACCEL
setp hm2_7i76e.0.stepgen.04.maxvel [JOINT_3]STEPGEN_MAXVEL
# ---closedloop stepper signals---
net b-pos-cmd <= joint.3.motor-pos-cmd
net b-vel-cmd <= joint.3.vel-cmd
net b-output => hm2_7i76e.0.stepgen.04.velocity-cmd
net b-pos-fb <= hm2_7i76e.0.stepgen.04.position-fb
net b-pos-fb => joint.3.motor-pos-fb
net b-enable <= joint.3.amp-enable-out
net b-enable => hm2_7i76e.0.stepgen.04.enableSo as it is the loop gets closed on the MESA board.
Now I would like to use that stepgen on the MESA board for another axis and have the b-axis working only in software.
I'm guessing I need to somehow provide the pid with a position feedback to get the DRO to function.
Does anybody have an idea if it is possible to close that loop in HAL and get the DRO to function?
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19 Apr 2020 12:01 - 19 Apr 2020 12:10 #164631
by bbsr_5a
Replied by bbsr_5a on topic Using motorless B-axis in HAL only
as you say manuel it is not a 5Axis Kinetics
just 3+2 as of Fusion360
so Just use Trivial kinetics as it cand move on Auto at all
a Post 5Axis will move all axis simultan like Powermill
and as you set 5axis kinetics it uses RTCP Rotating Tool Center Pos that the machine cand do
so you will be in real trouble if the joints are not there
YOU shoudt go for a 4AXIs only
use GEOMETRY XYZC and you are fine
you can try to HACK with a own component
LOOK at THCUD it hacks the Z axis
z_pos_out = z_pos_in;
z_fb_out = z_pos_in; // keep axis motor position fb from being confused
just feed the Component with your B Axis
just 3+2 as of Fusion360
so Just use Trivial kinetics as it cand move on Auto at all
a Post 5Axis will move all axis simultan like Powermill
and as you set 5axis kinetics it uses RTCP Rotating Tool Center Pos that the machine cand do
so you will be in real trouble if the joints are not there
YOU shoudt go for a 4AXIs only
use GEOMETRY XYZC and you are fine
you can try to HACK with a own component
LOOK at THCUD it hacks the Z axis
z_pos_out = z_pos_in;
z_fb_out = z_pos_in; // keep axis motor position fb from being confused
just feed the Component with your B Axis
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