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ilowpass: deprecate, smooth wheel jogs with jog-accel-fraction - #4809
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BsAtHome
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Nov 9, 2026
Motion plans wheel jogs itself under the axis and joint limits, and jog-accel-fraction lowers the acceleration of wheel jogs. With PLANNER_TYPE = 1 and a MAX_JERK they are also jerk limited. ilowpass in front of jog-counts only adds a lag after the wheel stops and defeats jog-vel-mode, as motion never sees the wheel stop. The pico pendants, shuttle.hal, the touchy example and the MPG example now feed the counts straight to jog-counts and set jog-accel-fraction to 0.25. The jog scales grow by the ilowpass scale they no longer divide. The scorbot-er-3 INI pointed at a shuttlexpress.hal that does not exist; it is shuttle.hal.
No in-tree config uses ilowpass any more. Point its man page and the component list at jog-accel-fraction, so it can be removed a release later.
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Follow-up to #4796, as agreed there: motion plans wheel jogs itself under the axis and joint limits, so ilowpass in front of
jog-countsis no longer needed.The first commit moves every in-tree user to
jog-accel-fraction0.25: the two picopendant.halfiles,configs/common/shuttle.halwith the scorbot-er-3 customization,touchy.hal.exampleand its notes, and thempg.adocexample. The jog scales grow by the ilowpass scale they no longer divide. The scorbot-er-3 INI pointed at ashuttlexpress.halthat does not exist; it isshuttle.hal.The second commit marks ilowpass deprecated in its man page and in the component list, so it can be removed a release later.
I compared both in a sim (1 ms servo, trapezoid planner, 1 mm click and 0.1 mm/click spins):
ilowpass does not soften a single click: motion chases the first filtered step at full acceleration. It only lowers the acceleration during a steady spin, and then trails the wheel by up to 2.4 mm. On a fast machine 0.25 sits between the two ilowpass gains during a spin, also caps the click, and stops 5-10 times sooner. On a slow machine it is softer than ilowpass was. With
PLANNER_TYPE = 1and aMAX_JERKthe wheel jogs are also jerk limited.The configs need hardware (ppmc, shuttle, hm2), so I have not run them.