Newsgroups: comp.robotics
Path: brunix!uunet!news.centerline.com!noc.near.net!gateway!miki!huangj
From: huangj@miki.pictel.com (Jian Huang)
Subject: Re: Stepper motor programs wanted
Message-ID: <1992Sep15.235009.1702@miki.pictel.com>
Organization: PictureTel Corporation
References: <1992Sep8.202500.27325@oswego.Oswego.EDU> <bubpe7.1wt@wang.com> <TED.92Sep10103428@lole.nmsu.edu>
Date: Tue, 15 Sep 1992 23:50:09 GMT
Lines: 5

  It is not easy to control a coordinate stepper system, specially at high speed. The algorithm you talked about was actually used in those IC-based NC machine many years ago (remember those tapes?). The implementation of the algorithm (called interpolation) only needs some adders and shifters which people could afford that time. The problem is that it has poor pulse evenness and gives stepper a lot of disturbance which causes its stall. It also is step-based other than time-base, which means you do calcul

ation at the step rate. Even fast processor will run into the trouble if you require a step rate near 1Mhz in microstepping system. This algorithm only works fine for those low speed (several hundred step/second) system and, of cause, drawing lines on screen. To use stepper motors in coordinate motion control system (such as robot) you need a good pulse generator which can output a specified pulse train evenly within a given time and a time-based interpolation algorithm. But I have found such system yet.

  Jian

