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Subject: 
Re: "Servo" Driver for NQC
Newsgroups: 
lugnet.robotics
Date: 
Tue, 29 Jan 2002 13:57:35 GMT
Original-From: 
Stephen Edwards <EDWARDS@CSantispam.VT.EDU>
Viewed: 
778 times
  
Rebel Transcanner wrote:
>

when it gets within a certain number of counts on the rotation
sensor, jumps to a slow speed by pulsing the motor (on, wait 1, off, wait
1).

I take it you are really doing on...float...on...float cycles
with your motor instead of using "off", which actually performs
active braking (on/off cycles are almost guaranteed to give serious
mechanical jitters).  Also, depending on the load on the motor, adjusting
the power level can also help--this tends to be much less effective
with lightly loaded motors, however.  Finally, gear trains can have
huge effects too, so be sure yours can be driven backwards easily and
smoothly, so that the momentum of the moving pieces works for you
during "float" periods.


                                 -- Steve

--
Stephen Edwards            604 McBryde Hall          Dept. of Computer Science
e-mail      : edwards@cs.vt.edu           U.S. mail: Virginia Tech (VPI&SU)
office phone: (540)-231-5723                         Blacksburg, VA  24061-0106
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Message has 2 Replies:
  Re: "Servo" Driver for NQC
 
"Stephen Edwards" <lego-robotics@crynwr.com> wrote in message news:3C56AA4F.409050....vt.edu... (...) wait (...) Nope, I'm using Off, because I need to brake the motor to pulse it. Floating it does almost nothing - the inertia of the motor carries (...) (23 years ago, 29-Jan-02, to lugnet.robotics)
  Re: "Servo" Driver for NQC
 
The ON/OFF bang-bang control you are trying has some problems that proportional control does not. While it is true that if the update rate is high enough, or the controlled plant damped enough, that switching a drive ON and OFF can simulate (...) (23 years ago, 30-Jan-02, to lugnet.robotics)

Message is in Reply To:
  "Servo" Driver for NQC
 
Hi All, I've got a bit of a problem! Whenever I do a cartesian (or other) robot model, I typically (in NQC) will program a "driver" which can spin the motors with the rotation sensors to any position and delecerate to finely reach the destination. (...) (23 years ago, 27-Jan-02, to lugnet.robotics)

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