RE: following error / Angular axis

[Granville Barker <Barker-at-boardtown.com>]

It looks like my motors are moving the wrong way, or my encoders where
hooked up backwards.  I reversed the a/b on the encoders and have it moving
all the axis.  The new problem is that if I try to move real fast I get
following errors, and it's not doing rectangular to polar conversions.  ( IS
EMC SUPPOSE TO? )  It seems like if the axis are defined as angular, and you
move x, it should move both axis to make the x move.

--
Granville Barker

-----Original Message-----
From: Chris Stratton [stratton-at-mdc.net]
Sent: Saturday, June 23, 2001 2:17 PM
To: Multiple recipients of list
Subject: Re: following error / Angular axis



Maybe try increasing the minimum following error parameter - the
following error limit gets scaled (by velocity?) and as a result the
effective limitmight at times be unreasonably low, so you can set a
minimum value.

You may also need to do some servo loop tuning, and check for
something like an offset error on your amps (assuming this is a servo
system).

> I just finished the hard part, getting Mandrake linux, rtlinux, and emc up
> and running with my hardware.  Now I have emc reportin the arm's position,
> and moving the arm.  I am getting the "following error" whenever I move
> either axis.  The robot also has two polar axis, but EMC is reporting the
> X,Y positions as direct reads from the controller rather than trying to
> interpolate the x,y based on the movement of both encoders.  
> 
> I'm sure there are alot of things in the ini file that aren't quite right
> yet, but I don't understand enough yet to get them set right.  
> 
> One oddity that i notice, is joggin the x, y axis in one direction moves
> very slowly, while the other direction takes off like a racecar.  ( any
> particular setting that effect this)?
> 
> Anyone have a good Angular sample ini file?
> 
> --
> Granville Barker
> 
> 


-- 
Christopher C. Stratton, stratton-at-mdc.net
Instrument Maker, Horn Player & Engineer
22 Adrian Street, Somerville, MA 02143
http://www.mdc.net/~stratton
NEW PHONE NUMBER: (617) 628-1062 home, 253-2606 MIT