Closed Loop
- andypugh
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12 Jul 2021 23:24 #214453
by andypugh
You have the PID all set up, but it isn't being used.
means that the commanded position goes direct to the stepgen with no influence from the PID.
Try, instead:
Replied by andypugh on topic Closed Loop
net z-enable pid.0.enable <= joint.0.amp-enable-out => stepgen.0.enable
net z-output pid.0.output
net z-pos-cmd joint.0.motor-pos-cmd => pid.0.command => stepgen.0.position-cmd
net z-vel-fb encoder.0.velocity => pid.0.feedback-deriv
net z-pos-fb joint.0.motor-pos-fb <= encoder.0.position => pid.0.feedbackYou have the PID all set up, but it isn't being used.
net ... joint.0.motor-pos-cmd ... stepgen.0.position-cmdTry, instead:
net z-enable pid.0.enable <= joint.0.amp-enable-out => stepgen.0.enable
net z-pos-cmd joint.0.motor-pos-cmd => pid.0.command
net z-vel-fb encoder.0.velocity => pid.0.feedback-deriv
net z-pos-fb joint.0.motor-pos-fb <= encoder.0.position => pid.0.feedback
net z-output pid.0.output => stepgen.0.position-cmdPlease Log in or Create an account to join the conversation.
- rohit269
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13 Jul 2021 06:58 #214498
by rohit269
Replied by rohit269 on topic Closed Loop
Many thanks for supporting me,
Sir after making this change in the hal file joint 0 error indicate and I am increase min ferror and ferror than check but after that stepper motor behavior is uncontrolled.
Sir now how solve this stepper motor behavior problem.
Sir after making this change in the hal file joint 0 error indicate and I am increase min ferror and ferror than check but after that stepper motor behavior is uncontrolled.
Sir now how solve this stepper motor behavior problem.
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13 Jul 2021 10:00 #214523
by andypugh
Replied by andypugh on topic Closed Loop
You will need to tune the PID.
First set FF0 to 1, FF1, FF2, Pgain, Igain, Dgain to 0.
That should leave you exactly where you were before, but with the PID in the data path.
Then try adding very small amounts of I and (and maybe P). when I say "small" I think I would start at 0.0001 (0.1um / mS) for I.
First set FF0 to 1, FF1, FF2, Pgain, Igain, Dgain to 0.
That should leave you exactly where you were before, but with the PID in the data path.
Then try adding very small amounts of I and (and maybe P). when I say "small" I think I would start at 0.0001 (0.1um / mS) for I.
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16 Jul 2021 13:35 #215052
by rohit269
Replied by rohit269 on topic Closed Loop
Many thanks for supporting me,
sir,
After tuning pid z axis motor run smoothly but i have new problem e.g. when i run G1 Z100 F300 then axis reach near z100 like 100.3 or 100.2 or 100.4 after that machine reach Z100.0010 very very slowly (Deadbend is 0.001) and when i increased Pgain for increasing this speed than z axis motor behave like jerking.
so please tell us how to solve this problem
sir,
After tuning pid z axis motor run smoothly but i have new problem e.g. when i run G1 Z100 F300 then axis reach near z100 like 100.3 or 100.2 or 100.4 after that machine reach Z100.0010 very very slowly (Deadbend is 0.001) and when i increased Pgain for increasing this speed than z axis motor behave like jerking.
so please tell us how to solve this problem
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16 Jul 2021 13:39 #215054
by andypugh
Replied by andypugh on topic Closed Loop
Thus sounds like I-term windup. You could try to reduce the maxerrorI setting.
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16 Jul 2021 13:52 #215055
by rohit269
Replied by rohit269 on topic Closed Loop
Many thanks supporting me,
sir,
where is this maxerrorI setting and kindly see ini file.
sir,
where is this maxerrorI setting and kindly see ini file.
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16 Jul 2021 13:55 #215056
by andypugh
Replied by andypugh on topic Closed Loop
linuxcnc.org/docs/2.8/html/man/man9/pid.9.html
It is quite likely that your existing HAL does not include MaxerrorI, and if it isn't in the HAL then nothing happens if you put it in the INI.
So, if you want to use it, you need to add a "setp" line to the HAL. You can either set the value directly in the HAL, or link to a new entry in the INI.
It is quite likely that your existing HAL does not include MaxerrorI, and if it isn't in the HAL then nothing happens if you put it in the INI.
So, if you want to use it, you need to add a "setp" line to the HAL. You can either set the value directly in the HAL, or link to a new entry in the INI.
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17 Jul 2021 09:37 - 17 Jul 2021 21:14 #215127
by rohit269
Replied by rohit269 on topic Closed Loop
Many thanks for supporting me,
Sir,
After add errorI than improve the speed up to 18mm/min but more than 18mm/min axis motor behavior like earlier and also when run e.g. G1 z-10 f150 than starting to 3 or 4mm axis motor jurking than run smoothly and one more question I am testing axis scale with metal scale e.g. G1 z100 f100 and that time move 0.400 higher (z100.400Z) sir kindly tell how to solve this problem.
Sir,
After add errorI than improve the speed up to 18mm/min but more than 18mm/min axis motor behavior like earlier and also when run e.g. G1 z-10 f150 than starting to 3 or 4mm axis motor jurking than run smoothly and one more question I am testing axis scale with metal scale e.g. G1 z100 f100 and that time move 0.400 higher (z100.400Z) sir kindly tell how to solve this problem.
Last edit: 17 Jul 2021 21:14 by rohit269.
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19 Jul 2021 07:49 #215292
by rohit269
Replied by rohit269 on topic Closed Loop
Many thanks for supporting me,
Sir,
After add errorI than improve the speed up to 18mm/min but more than 18mm/min axis motor behavior like earlier and also when run e.g. G1 z-10 f150 than starting to 3 or 4mm axis motor jurking than run smoothly and one more question I am testing axis scale with metal scale e.g. G1 z100 f100 and that time move 0.400 higher (z100.400Z) sir kindly tell how to solve this problem.
Sir,
After add errorI than improve the speed up to 18mm/min but more than 18mm/min axis motor behavior like earlier and also when run e.g. G1 z-10 f150 than starting to 3 or 4mm axis motor jurking than run smoothly and one more question I am testing axis scale with metal scale e.g. G1 z100 f100 and that time move 0.400 higher (z100.400Z) sir kindly tell how to solve this problem.
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19 Jul 2021 12:44 #215321
by andypugh
Replied by andypugh on topic Closed Loop
18mm/min is very slow. Are you sure that is what you mean?
PID tuning is a process, and every machine is different. All I can suggest is that you read articles on the internet about the subject to try to understand how it works.
PID itself is very simple in terms of what calculations it does, but applying it to a specific application can take a lot of experiment.
PID tuning is a process, and every machine is different. All I can suggest is that you read articles on the internet about the subject to try to understand how it works.
PID itself is very simple in terms of what calculations it does, but applying it to a specific application can take a lot of experiment.
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