Damping Bender Corrections with VTube-LASER

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Damping Bender Corrections

Vtube-laser 1.77.3.jpg


VTube-LASER can add damping correction data in order to avoid over-steer in bender correction by reducing the total correction sent to the bender - typically by 50% of the correction.

When to Use Damping

Two adjacent 90 degree bends that are close to each other followed by a long straight causes VTube (and other measuring solutions) to overcorrect the end of the long straight. The end is supposed be corrected to the middle straight (the MASTER) like this:

Vtube-automatic proper correction tube swing.jpg

But what this tube configuration may cause is a wag-the-tail oscillation in the correction loop like this:

Vtube-automatic proper correction tube swing too much.jpg

The result is a correction that causes the leg to overshoot the target.

Two Kinds of Damping

VTube has two kinds of automatic damping. The first one reduces the correction by 50% in any of three sets of bender axis data (the Length, Rotation, and Bend). It allows for this damping in each axis independently – so they can choose the appropriate axis to damp. The second kind of damping is based on the previous adjustment values. Using the previous value causes the correction to be reduced even faster if this kind of oscillation exists.

Vtube-autocorrectiondamping green curve.jpg

When NOT to Use Damping

Damping is not helpful if your tube does not have the characteristic shape shown above. If the tube you are measuring does not have short straights that are basically "jogs" or offsets in longer sections of tubes, then you should turn damping off by unchecking the damping check boxes and/or ignoring all damping report data.

Also, do not rely on damping corrections in reports if the blue columns in the bender data setup menu are set to zeros (not actual bender data). The best time to use damping is when short jogs exist, and there is a connection the bender so that you can reset the blue columns to existing (actual) bender data first.

Vtube-autocorrectdamping pulldownbox.jpg

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