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Opentrons / opentrons

Software for writing protocols and running them on the Opentrons Flex and Opentrons OT-2
https://opentrons.com
Apache License 2.0
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bug: Jerky motion during touch_tip() command #9141

Open danolson1 opened 2 years ago

danolson1 commented 2 years ago

Overview

When I have the robot do a touch_tip() operation, it immediately jerks the tip before starting the touch_tip() operation. I think this might be causing small droplets of liquid to be sprayed into adjacent wells.

Steps to reproduce

Run the touch_tip() command on a 384 well plate at a slow speed (5 mm/min). I'm sure it happens at fast speeds too, but it is much more visually obvious when set to a slower speed.

I am doing this via the Jupyter interface, in case that matters.

Current behavior

The tip immediately jerks back and forth, then proceeds to slowly touch the walls.

Expected behavior

No jerky behavior. This might require smoothing the acceleration of the motion commands.

danolson1 commented 2 years ago

When I set the touch_tip parameter to True in the dispense() function, and use it on a full column of a 384 well plate, the jerky motion seems to be causing the Y-axis to drift, which eventually causes pipetting in the wrong wells.

SyntaxColoring commented 2 years ago

@danolson1 Which robot software version is this on?

danolson1 commented 2 years ago

Server version 4.7.0 Firmware version: v1.1.0-25e5cea

SyntaxColoring commented 2 years ago

Got it. I ask because our v5.0 beta is having problems where the whole touch_tip() is slower (#9135), presumably because it's erroneously stalling for a moment between each movement within the touch_tip().

But it sounds like you're talking about something different: the movements are coming right after each other, as they should, but the change in direction is too abrupt?