# How to achieve rapid positioning in the final stage of hydraulic servo？

**URL:** <https://forum.deltamotion.com/t/how-to-achieve-rapid-positioning-in-the-final-stage-of-hydraulic-servo/969>\
**Category:** Motion System Design\
**Created:** [December 18, 2021, 4:06pm UTC](https://forum.deltamotion.com/t/how-to-achieve-rapid-positioning-in-the-final-stage-of-hydraulic-servo/969 "2021-12-18T16:06:34Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![mars\_bruce\_lee](https://forum.deltamotion.com/letter_avatar_proxy/v4/letter/m/a587f6/32.png) [@mars\_bruce\_lee](https://forum.deltamotion.com/u/mars_bruce_lee)\
**Post date:** [December 18, 2021, 4:06pm UTC](https://forum.deltamotion.com/t/how-to-achieve-rapid-positioning-in-the-final-stage-of-hydraulic-servo/969/1 "2021-12-18T16:06:34Z")

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How to achieve rapid positioning in the final stage of hydraulic servo, which parameters are generally adjusted for rapid positioning  
In many projects, the positioning accuracy time in the final positioning stage is too long. Adjusting which parameters can effectively improve the positioning time in the final stage  
Or by what means to determine which parameters to adjust

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**Author:** ![ndzied1](https://forum.deltamotion.com/letter_avatar_proxy/v4/letter/n/77aa72/32.png) [@ndzied1](https://forum.deltamotion.com/u/ndzied1)\
**Post date:** [December 18, 2021, 7:30pm UTC](https://forum.deltamotion.com/t/how-to-achieve-rapid-positioning-in-the-final-stage-of-hydraulic-servo/969/2 "2021-12-18T19:30:24Z")

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A higher deceleration will create a motion profile that tries to stay faster longer before slowing down. The natural frequency of the system will limit what is possible here.

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**Author:** ![mars\_bruce\_lee](https://forum.deltamotion.com/letter_avatar_proxy/v4/letter/m/a587f6/32.png) [@mars\_bruce\_lee](https://forum.deltamotion.com/u/mars_bruce_lee)\
**Post date:** [December 19, 2021, 2:03pm UTC](https://forum.deltamotion.com/t/how-to-achieve-rapid-positioning-in-the-final-stage-of-hydraulic-servo/969/3 "2021-12-19T14:03:35Z")

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![截图00](https://forum.deltamotion.com/uploads/default/original/1X/536eb92498015ac56996828ea610134bd28ca911.png)

[Manipulator\_Rotate.rmcplotx](https://forum.deltamotion.com/uploads/short-url/znuztVHTBEyX8qAj7d3v88fnjIc.rmcplotx) (1015.7 KB)

The curve part of the above figure  
Which parameter is inappropriate, which caused the slow positioning in the final stage

Tuning Position

Too much Acceleration Feed Forward？

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**Author:** ![Paul\_Huumala](https://forum.deltamotion.com/letter_avatar_proxy/v4/letter/p/22d042/32.png) [@Paul\_Huumala](https://forum.deltamotion.com/u/Paul_Huumala)\
**Post date:** [December 20, 2021, 4:42pm UTC](https://forum.deltamotion.com/t/how-to-achieve-rapid-positioning-in-the-final-stage-of-hydraulic-servo/969/4 "2021-12-20T16:42:15Z")

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The overshoot at the beginning of the move and undershoot at the end indicate that the Acceleration Feed Forward is too high. I also think you could use some Output Filter (larger value = less filtering) and then increase your proportional and integral gains as well.

For the Output Filter, I would start with a value like 50 Hz and reduce it if my control output was looking too “grassy” or fuzzy.