Re: [CAD_CAM_EDM_DRO] Anyone done pll / servo speed control using "RC" stuff?

Servo means 'slave'. In other words something that should do what it is
told. This is achieved by measuring the parameter to be controlled,
comparing it with the desired value, producing an error and using that to
make an adjustment. The parameter to be controlled could be speed, current
or whatever.

I think what you need to control speed accurately under varying load is a
tacho coupled to the motor to provide an actual speed signal and use a speed
controller to act as a speed servo. You could use an encoder and a PLL but
that is increasing the complexity considerably.

An RC controller is a very simple speed controller converting the PWM input
from the receiver to produce a chopped variable voltage dc output to vary
motor speed. Usually they are single ended and so cannot reverse or brake
the motor (except very crudely).

One of your considerations is will a single ended controller be able to
control the motor especially give the performance you require. Or do you
need a bidirectional controller that will accept energy from the motor to
brake it.

Regards Peter

----- Original Message -----
From: "Mark" <mfraser@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Tuesday, February 04, 2003 7:16 PM
Subject: [CAD_CAM_EDM_DRO] Anyone done pll / servo speed control using "RC"
stuff?


> While I'd prefer a Gecko320, I have an application that wants 40 or
> more amps at 30vdc to run a high-performance DC PM motor.
>
> I was handed a switch-mode driver for this, which takes pulse trains
> from
> model aircraft-style RC receivers - this isn't surprising since the
> motor
> is for model aircraft racing apps.....
>
> But the application needs quite precise speed control under widely
> varying loads, and everything about it says "servo" as in servomotor,
> rather than "servo" as in RC modeling.
>
> I'm not up to designing a PLL-based setup, especially as this is a
> 1-off application.
>
> Anyone out there care to direct me, disabuse me, abuse me or otherwise
> contribute?
>
> Thanks / mark
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
> Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
>
> Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...,
timg@...
> Moderator: pentam@... indigo_red@... [Moderators]
> URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
>
> OFF Topic POSTS: General Machining
> If you wish to post on unlimited OT subjects goto:
aol://5863:126/rec.crafts.metalworking or go thru Google.com to reach it if
you have trouble.
> http://www.metalworking.com/news_servers.html
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
sister site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> bill
> List Mom
> List Owner
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>