Rather than the hard to control air wrench have you considered using a small DC motor with an encoder and gear reduction? Some years ago there was a lengthy series of posts on CNCZONE about such a system.
-----Original Message----- From: John Dammeyer <jo...@autoartisans.com> Sent: November 21, 2021 2:41 AM To: Enhanced Machine Controller (EMC) <emc-users@lists.sourceforge.net> Subject: [Emc-users] Closed loop control of air motors. Has anyone ever tried any sort of closed loop control of an air motor similar the one on this butterfly impact wrench. https://www.penntoolco.com/52-424-9/ In order to not have both the TTS and R8 collet drop out of the spindle I'd like to be able to limit the number of turns to 2. What I've found however, is that 10mS pulses to the valve supplying air for CCW rotation barely move it until it's unloaded and then it immediately spins up very fast and does at least 4 to 8 turns. That's way too many. I've only got a one pulse per rev hall sensor detecting a magnet on the socket. But I suspect between reaction time of the valve, the compressibility of air and the rotary inertia of the motor that unless there is some sort of constant load that control is pretty well impossible. With servos, if the motor is loaded and then suddenly totally unloaded, it too might turn a number of revolutions before the control system could bring it back down to the original speed. Short of adding some sort of mechanical brake am I trying to do the impossible? Oh and to avoid another 1000 words to explain I've added a picture. John _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users