Jerky motion with spiral cutting for circles
28 Apr 2014 03:48 - 28 Apr 2014 03:49 #46387
by Duc
Jerky motion with spiral cutting for circles was created by Duc
Im running into issues with the machine being jerky when running spiral cutting for a circle code versus a code output that only output simple circles with step overs.
Machine specs
Intel P4 1.8 ghz
1.5 gigs ram
ATI 9800 Pro
Mesa 5i25/7i76/7i84
The machine will behave perfectly if Im running simple G-code but if running code that uses alot of G-code changes then I get jerky movement. Seems like it is running one line then a short pause till the next line.
Any ideas
Machine specs
Intel P4 1.8 ghz
1.5 gigs ram
ATI 9800 Pro
Mesa 5i25/7i76/7i84
The machine will behave perfectly if Im running simple G-code but if running code that uses alot of G-code changes then I get jerky movement. Seems like it is running one line then a short pause till the next line.
Any ideas
Last edit: 28 Apr 2014 03:49 by Duc.
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28 Apr 2014 04:38 #46391
by PCW
Replied by PCW on topic Jerky motion with spiral cutting for circles
Its likely your spiral gcode is made of lots of short segments
Have you looked at the G64 options?
linuxcnc.org/docs/html/common/User_Conce...c:trajectory-control
Have you looked at the G64 options?
linuxcnc.org/docs/html/common/User_Conce...c:trajectory-control
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28 Apr 2014 06:43 #46399
by Duc
Tried both G61 and G64. Problem was noticably worse with G61.
Looking at my .ini file I do have different acceleration numbers for X and Y. X is 4 and Y is 2. Anything higher than 2 on y results in joint following errors.
Replied by Duc on topic Jerky motion with spiral cutting for circles
Its likely your spiral gcode is made of lots of short segments
Have you looked at the G64 options?
linuxcnc.org/docs/html/common/User_Conce...c:trajectory-control
Tried both G61 and G64. Problem was noticably worse with G61.
Looking at my .ini file I do have different acceleration numbers for X and Y. X is 4 and Y is 2. Anything higher than 2 on y results in joint following errors.
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28 Apr 2014 07:28 #46406
by PCW
Replied by PCW on topic Jerky motion with spiral cutting for circles
Those seem like very low acceleration numbers
I would suspect tuning issues or too tight following error limits
I would suspect tuning issues or too tight following error limits
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28 Apr 2014 07:36 #46408
by Duc
Wasnt to sure what FERROR and MIN_FERROR I should use on the machine. I know its not a super fast CNC since its a old bridgeport boss 5 with original steppers. The joint follow error could be tied to the FERROR limits according to the wiki.
What is a good rough number to use for them to increase the acceleration.
Replied by Duc on topic Jerky motion with spiral cutting for circles
Those seem like very low acceleration numbers
I would suspect tuning issues or too tight following error limits
Wasnt to sure what FERROR and MIN_FERROR I should use on the machine. I know its not a super fast CNC since its a old bridgeport boss 5 with original steppers. The joint follow error could be tied to the FERROR limits according to the wiki.
What is a good rough number to use for them to increase the acceleration.
#********************
# Axis X
#********************
[AXIS_0]
TYPE = LINEAR
HOME = .5
FERROR = 0.005
MIN_FERROR = 0.0005
MAX_VELOCITY = 1.66666666667
MAX_ACCELERATION = 4.0
# these are in nanoseconds
DIRSETUP = 200
DIRHOLD = 200
STEPLEN = 1000
STEPSPACE = 2000
STEP_SCALE = -10000.0
MIN_LIMIT = -0.0
MAX_LIMIT = 18.0
HOME_OFFSET = -0.050000
HOME_SEARCH_VEL = -0.2
HOME_LATCH_VEL = -0.016667
HOME_FINAL_VEL = 0.000000
HOME_USE_INDEX = NO
HOME_IGNORE_LIMITS = YES
HOME_SEQUENCE = 1
#********************
# Axis Y
#********************
[AXIS_1]
TYPE = LINEAR
HOME = .050
FERROR = 0.005
MIN_FERROR = 0.0005
MAX_VELOCITY = 1.667
MAX_ACCELERATION = 2.0
# these are in nanoseconds
DIRSETUP = 200
DIRHOLD = 200
STEPLEN = 1000
STEPSPACE = 2000
STEP_SCALE = -10000.0
MIN_LIMIT = -0.0
MAX_LIMIT = 12.0
HOME_OFFSET = -0.060000
HOME_SEARCH_VEL = -0.2
HOME_LATCH_VEL = -0.016667
HOME_FINAL_VEL = 0.000000
HOME_USE_INDEX = NO
HOME_IGNORE_LIMITS = YES
HOME_SEQUENCE = 2
#********************
# Axis Z
#********************
[AXIS_2]
TYPE = LINEAR
HOME = 0.0
FERROR = 0.005
MIN_FERROR = 0.0005
MAX_VELOCITY = 1.667
MAX_ACCELERATION = 2.0
# these are in nanoseconds
DIRSETUP = 200
DIRHOLD = 200
STEPLEN = 1000
STEPSPACE = 2000
STEP_SCALE = -10000.0
MIN_LIMIT = -5.0
MAX_LIMIT = 0.001
HOME_OFFSET = 0.050000
HOME_SEARCH_VEL = 0.100000
HOME_LATCH_VEL = 0.016667
HOME_FINAL_VEL = 0.000000
HOME_USE_INDEX = NO
HOME_IGNORE_LIMITS = YES
HOME_SEQUENCE = 0Please Log in or Create an account to join the conversation.
28 Apr 2014 08:38 #46409
by PCW
Replied by PCW on topic Jerky motion with spiral cutting for circles
I had forgotten that this was a step/dir machine
If you have following errors its likely that the stepgen_maxaxccel values are not set
(they should be set to about 1.2X the maxaccel values for the corresponding axis)
for a slow stepgen machine I might set maxaccel to 2 to 5x maxvel
If you have following errors its likely that the stepgen_maxaxccel values are not set
(they should be set to about 1.2X the maxaccel values for the corresponding axis)
for a slow stepgen machine I might set maxaccel to 2 to 5x maxvel
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28 Apr 2014 09:19 #46411
by Duc
Replied by Duc on topic Jerky motion with spiral cutting for circles
so I need to adjust the values in the .hal file
Current
Suggested?
Current
#*******************
# AXIS X
#*******************
# Step Gen signals/setup
setp hm2_5i25.0.stepgen.00.dirsetup [AXIS_0]DIRSETUP
setp hm2_5i25.0.stepgen.00.dirhold [AXIS_0]DIRHOLD
setp hm2_5i25.0.stepgen.00.steplen [AXIS_0]STEPLEN
setp hm2_5i25.0.stepgen.00.stepspace [AXIS_0]STEPSPACE
setp hm2_5i25.0.stepgen.00.position-scale [AXIS_0]STEP_SCALE
setp hm2_5i25.0.stepgen.00.step_type 0
setp hm2_5i25.0.stepgen.00.control-type 0
setp hm2_5i25.0.stepgen.00.maxaccel 5.0
setp hm2_5i25.0.stepgen.00.maxvel 2.1
net x-pos-fb axis.0.motor-pos-fb <= hm2_5i25.0.stepgen.00.position-fb
net x-pos-cmd axis.0.motor-pos-cmd => hm2_5i25.0.stepgen.00.position-cmd
net x-enable axis.0.amp-enable-out => hm2_5i25.0.stepgen.00.enable
# ---setup home / limit switch signals---
net both-home-x => axis.0.home-sw-in
net both-home-x => axis.0.neg-lim-sw-in
net both-home-x => axis.0.pos-lim-sw-in
#*******************
# AXIS Y
#*******************
# Step Gen signals/setup
setp hm2_5i25.0.stepgen.01.dirsetup [AXIS_1]DIRSETUP
setp hm2_5i25.0.stepgen.01.dirhold [AXIS_1]DIRHOLD
setp hm2_5i25.0.stepgen.01.steplen [AXIS_1]STEPLEN
setp hm2_5i25.0.stepgen.01.stepspace [AXIS_1]STEPSPACE
setp hm2_5i25.0.stepgen.01.position-scale [AXIS_1]STEP_SCALE
setp hm2_5i25.0.stepgen.01.step_type 0
setp hm2_5i25.0.stepgen.01.control-type 0
setp hm2_5i25.0.stepgen.01.maxaccel 2.5
setp hm2_5i25.0.stepgen.01.maxvel 2.1
net y-pos-fb axis.1.motor-pos-fb <= hm2_5i25.0.stepgen.01.position-fb
net y-pos-cmd axis.1.motor-pos-cmd => hm2_5i25.0.stepgen.01.position-cmd
net y-enable axis.1.amp-enable-out => hm2_5i25.0.stepgen.01.enable
# ---setup home / limit switch signals---
net both-home-y => axis.1.home-sw-in
net both-home-y => axis.1.neg-lim-sw-in
net both-home-y => axis.1.pos-lim-sw-in
#*******************
# AXIS Z
#*******************
# Step Gen signals/setup
setp hm2_5i25.0.stepgen.02.dirsetup [AXIS_2]DIRSETUP
setp hm2_5i25.0.stepgen.02.dirhold [AXIS_2]DIRHOLD
setp hm2_5i25.0.stepgen.02.steplen [AXIS_2]STEPLEN
setp hm2_5i25.0.stepgen.02.stepspace [AXIS_2]STEPSPACE
setp hm2_5i25.0.stepgen.02.position-scale [AXIS_2]STEP_SCALE
setp hm2_5i25.0.stepgen.02.step_type 0
setp hm2_5i25.0.stepgen.02.control-type 0
setp hm2_5i25.0.stepgen.02.maxaccel 2.5
setp hm2_5i25.0.stepgen.02.maxvel 2.1Suggested?
#*******************
# AXIS X
#*******************
# Step Gen signals/setup
setp hm2_5i25.0.stepgen.00.dirsetup [AXIS_0]DIRSETUP
setp hm2_5i25.0.stepgen.00.dirhold [AXIS_0]DIRHOLD
setp hm2_5i25.0.stepgen.00.steplen [AXIS_0]STEPLEN
setp hm2_5i25.0.stepgen.00.stepspace [AXIS_0]STEPSPACE
setp hm2_5i25.0.stepgen.00.position-scale [AXIS_0]STEP_SCALE
setp hm2_5i25.0.stepgen.00.step_type 0
setp hm2_5i25.0.stepgen.00.control-type 0
setp hm2_5i25.0.stepgen.00.maxaccel 5.0
setp hm2_5i25.0.stepgen.00.maxvel 1
net x-pos-fb axis.0.motor-pos-fb <= hm2_5i25.0.stepgen.00.position-fb
net x-pos-cmd axis.0.motor-pos-cmd => hm2_5i25.0.stepgen.00.position-cmd
net x-enable axis.0.amp-enable-out => hm2_5i25.0.stepgen.00.enable
# ---setup home / limit switch signals---
net both-home-x => axis.0.home-sw-in
net both-home-x => axis.0.neg-lim-sw-in
net both-home-x => axis.0.pos-lim-sw-in
#*******************
# AXIS Y
#*******************
# Step Gen signals/setup
setp hm2_5i25.0.stepgen.01.dirsetup [AXIS_1]DIRSETUP
setp hm2_5i25.0.stepgen.01.dirhold [AXIS_1]DIRHOLD
setp hm2_5i25.0.stepgen.01.steplen [AXIS_1]STEPLEN
setp hm2_5i25.0.stepgen.01.stepspace [AXIS_1]STEPSPACE
setp hm2_5i25.0.stepgen.01.position-scale [AXIS_1]STEP_SCALE
setp hm2_5i25.0.stepgen.01.step_type 0
setp hm2_5i25.0.stepgen.01.control-type 0
setp hm2_5i25.0.stepgen.01.maxaccel 5
setp hm2_5i25.0.stepgen.01.maxvel 1
net y-pos-fb axis.1.motor-pos-fb <= hm2_5i25.0.stepgen.01.position-fb
net y-pos-cmd axis.1.motor-pos-cmd => hm2_5i25.0.stepgen.01.position-cmd
net y-enable axis.1.amp-enable-out => hm2_5i25.0.stepgen.01.enable
# ---setup home / limit switch signals---
net both-home-y => axis.1.home-sw-in
net both-home-y => axis.1.neg-lim-sw-in
net both-home-y => axis.1.pos-lim-sw-in
#*******************
# AXIS Z
#*******************
# Step Gen signals/setup
setp hm2_5i25.0.stepgen.02.dirsetup [AXIS_2]DIRSETUP
setp hm2_5i25.0.stepgen.02.dirhold [AXIS_2]DIRHOLD
setp hm2_5i25.0.stepgen.02.steplen [AXIS_2]STEPLEN
setp hm2_5i25.0.stepgen.02.stepspace [AXIS_2]STEPSPACE
setp hm2_5i25.0.stepgen.02.position-scale [AXIS_2]STEP_SCALE
setp hm2_5i25.0.stepgen.02.step_type 0
setp hm2_5i25.0.stepgen.02.control-type 0
setp hm2_5i25.0.stepgen.02.maxaccel 5
setp hm2_5i25.0.stepgen.02.maxvel 1.0Please Log in or Create an account to join the conversation.
28 Apr 2014 10:23 #46415
by PCW
Replied by PCW on topic Jerky motion with spiral cutting for circles
if the maxvel numbers in the ini file are all 4, yes
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28 Apr 2014 14:41 #46419
by Rick G
Replied by Rick G on topic Jerky motion with spiral cutting for circles
In addition to what PCW has suggested you might want to look here...
www.linuxcnc.org/index.php/english/forum...stersprograms-wanted
Rick G
www.linuxcnc.org/index.php/english/forum...stersprograms-wanted
Rick G
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