Is the PID controller running on the PC under LCNC or is this an external PID controller you built?
What are the numbers, the loop period, motor speed and numer of encoder lines. and so on? I don't think the fact that there is a worm gear matters. The problem, I bet is the large inertia of the system. Aside from proper tuning of the PID gains you could change the system to use a nested or "cascade" PID. THis allows the velocity setpoint to be controlled by the position error see the section "cascade" in the wiki article https://en.wikipedia.org/wiki/PID_controller I think you want a very fast loop i=for the inner PID. LIkely it wouldbe in external hardwarelike a microcontroller or FPGA. (does MESA do the PID algorithm in the FPGA? It should.) On Sun, Sep 19, 2021 at 3:39 PM Gene Heskett <ghesk...@shentel.net> wrote: > Greetings all; > As most of you know, I built a servo from scratch for a BS-1. > > But I am not at all happy with its performance. > It is a motor with a worm output, driving the worm of the bs-1. And it > has an A/B quad encoder in it. > > But I must rather severely limit its run speed because the PID doesn't > see the null coming near fast enough to slow it and stop a couple > arcseconds early. I can't allow it to use reverse to stop as the motor > seems to be a near short circuit then, crowbarring the power supply, > causing a 2 to 3 minute dead time for the 450 watt psu to cool, so I > must limit its speed to disallow its use of reverse to accomplish the > stop. With 2 worms in series the scale for a 360 degree full turn is of > coarse huge. If it could be throttled to a gradual stop by anticipating > the coming null, I could probably run it 2 to 4x faster for a cruising > speed. > > So my question is, which of the pid inputs would if raised, better > anticipate the approaching null, slowing it over the last 5 angular > minutes of a turn, ideally to a stop within an arc-second of the command > from the gcode? > > Thanks all. > > Cheers, Gene Heskett > -- > "There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." > -Ed Howdershelt (Author) > If we desire respect for the law, we must first make the law respectable. > - Louis D. Brandeis > Genes Web page <http://geneslinuxbox.net:6309/gene> > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
