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Some problem with the acceleration in linear mode
#1
Hello.

I have some problem with the acceleration in linear mode.

Actually it is more correct that the problem is 'Jerk'.

When i tried a simple motion program which is set with 'TA 400' and 'TS 0', i expected that the total acceleration time will be 400ms. But it didn't work , it derived 420ms in plots for 'velocity- time'.

So i tried the motion program with another value for TA and TS. It wasn't changed with having an interval, 20ms. (if i test it with Ta 500 and TS 0, the total acceleration time is resulted in 520ms.

And then i saw an reduction trend for 20ms when the acceleration value went to 'zero' in the plots for 'acceleration-time'. i just expected the acceleration value went to 'zero' ,just like a pulse without any reduction trend or decreasing trend.

Why didn't it work as what i expect? i searched some initial value for acceleration , jerk or speed in coordinate system for motion program. But i couldn't catch anything.

So, i'm looking for answers.

Thank you reading my question.


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#2
Motor[*].InvJmax parameter will limit jerk magnitude regardless of your motion program requests.

This parameter's default value is 20 motor units/sec^2

Perhaps this is what you are seeing.
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#3
(10-10-2019, 05:42 AM)DaveBarnett Wrote: Motor[*].InvJmax parameter will limit jerk magnitude regardless of your motion program requests.

This parameter's default value is 20 motor units/sec^2

Perhaps this is what you are seeing.

Thank you for your answer.

I already tried to include the parameter, which is '0.0000001'.

In addition 'Motor[*].InvAmax' and 'Motor[*].InvDmax is also included in the motion prog.

But there isn't any change. :-(


[/quote]


I got it from my coworker. It comes out from servo-cycle. For gathering on servo-cycle(1ms), the plot is gathered with 2 servo-cycle(2ms).

So i get the reduction trend from the plot as 2ms(sorry , it wasn't 20ms).

Thank you :-)
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#4
Is your coordinate system in segmentation mode (Coord[x].SegMoveTime > 0)?

It looks like a setting of SegMoveTime = 10 msec would explain what you are seeing.
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#5
(10-11-2019, 09:25 AM)curtwilson Wrote: Is your coordinate system in segmentation mode (Coord[x].SegMoveTime > 0)?

It looks like a setting of SegMoveTime = 10 msec would explain what you are seeing.

Thank you for your answer.

Hm.. I knew that i tried the result in non-segmentation mode(coord[].segmovetime=0, linear mode).

Any way, if i have a problem just like the result again, i would solve it from your answer :-).

Thank you. Have a nice day~!
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