Positioning issue on remora with nvem

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03 Aug 2024 12:58 #306842 by Lpkkk
Hi 
I've got some weird issue with my configuration. 
When I home I should be on X0Y0. But I'm always 0.003 - 0.005 from this point on both axes. 

Same when I go to X50, it is stopping at 49.995. DTG shows 0. 
I've noticed in hal config that j0pos-cmd and j0pos-fb are different. 
It happens on all of the axes 
​​​Can someone advise anything? 
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06 Aug 2024 03:04 #307053 by scotta
With a stepper based system you will be limited by the distance moved by one step. In the example you have shown your step scale is 160, ie 160 steps / mm. Therefore 1 step is 0.00625mm

The difference between the commanded and actual position is 0.0063mm (0.00625) or one step. The default deadband within the Remora component is 1/step_scale or 1 step. You can set the deadband to be smaller but then the control loop will hunt as the step resolution never allows the commanded position to be reached.

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06 Aug 2024 14:57 #307096 by Lpkkk
I've tried different deadband settings by adding to my hal :

setp remora.joint.0.pgain [JOINT_0]P_GAIN
setp remora.joint.0.ff1gain [JOINT_0]FF1_GAIN
setp remora.joint.0.deadband [JOINT_0]DEADBAND

And to my ini in joint 0 section :

P_GAIN = 1
FF1_GAIN = 1
DEADBAND = 0.001

I've tried different values like 1, 0.5, 1.1, all of them didn't change anything.

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06 Aug 2024 19:23 - 06 Aug 2024 19:31 #307118 by Lpkkk
With those settings(attached) i'm nearly there. Sometimes it is spot on, but sometimes like on the screenshot
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Last edit: 06 Aug 2024 19:31 by Lpkkk.

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