Wheel encoding
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Posts: 46,084
Hi All,
I now have wheel encoders on my robot and am looking for ways to turn
the pulses they generate into useful information. My primary interest
for the moment is straight line tracking. Somedays my robot travels
straight, somedays it drifts left and sometimes it will drift right
(fickel servos). It's a constant, irritating problem and I'm getting
tired of having to recalibrate my pulses everytime I run it.
So I'm wondering how other Stamp users have overcome this problem. I
was thinking of looking into the PWMPAL but I'm still not sure it
will do what I need it to do. Thanks.
-Dave
I now have wheel encoders on my robot and am looking for ways to turn
the pulses they generate into useful information. My primary interest
for the moment is straight line tracking. Somedays my robot travels
straight, somedays it drifts left and sometimes it will drift right
(fickel servos). It's a constant, irritating problem and I'm getting
tired of having to recalibrate my pulses everytime I run it.
So I'm wondering how other Stamp users have overcome this problem. I
was thinking of looking into the PWMPAL but I'm still not sure it
will do what I need it to do. Thanks.
-Dave
Comments
http://www.al-williams.com/pak7.htm. Of course, you already have the wheels,
or I'd recommend http://www.al-williams.com/pak11.htm -- this uses a mouse
to read position. You can gut a mechanical mouse and use it for position
data or -- and this is really slick -- use an optical mouse. Of course, the
optical mouse has to practically drag the ground which may not be practical
in this case, but it works great on my drill press table! Even then, a $5
mechanical mouse will provide encoders and the chip reads out very easily
using RS232.
Regards,
Al Williams
AWC
>
Original Message
> From: nuclearspin2000 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=DAY0AhPaYzyRxBUw-Gm3HEtmeCs5GoSNBPxwDgDsgoAaM3v59grgpG8bxUJahJ5Vv4FBDxi5hFuWf2j6XNEeRn8LC5I]nuclearspin2000@y...[/url
> Sent: Saturday, November 08, 2003 11:43 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Wheel encoding
>
>
> Hi All,
>
> I now have wheel encoders on my robot and am looking for ways to turn
> the pulses they generate into useful information. My primary interest
> for the moment is straight line tracking. Somedays my robot travels
> straight, somedays it drifts left and sometimes it will drift right
> (fickel servos). It's a constant, irritating problem and I'm getting
> tired of having to recalibrate my pulses everytime I run it.
>
> So I'm wondering how other Stamp users have overcome this problem. I
> was thinking of looking into the PWMPAL but I'm still not sure it
> will do what I need it to do. Thanks.
>
> -Dave
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
> Subject and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
>
>
following article.
http://www.seattlerobotics.org/encoder/200010/dead_reckoning_article.htm
l
Original Message
From: nuclearspin2000 [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=-HYhUNThiuUCN7sF4RjzYj04StpRC6dr3KebFJ8LsMVDzxkeFL0-iHph1niO6RUmnbyRqB54abyYu_pvjYJd8fc]nuclearspin2000@y...[/url
Sent: Saturday, November 08, 2003 11:43 PM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Wheel encoding
Hi All,
I now have wheel encoders on my robot and am looking for ways to turn
the pulses they generate into useful information. My primary interest
for the moment is straight line tracking. Somedays my robot travels
straight, somedays it drifts left and sometimes it will drift right
(fickel servos). It's a constant, irritating problem and I'm getting
tired of having to recalibrate my pulses everytime I run it.
So I'm wondering how other Stamp users have overcome this problem. I
was thinking of looking into the PWMPAL but I'm still not sure it
will do what I need it to do. Thanks.
-Dave
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
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Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
and is exactly what I'm using. You can also find the schematic at
www.acroname.com. Here's a tip, those Hammamatsu sensors do not like
to be hooked up backwards to the supply voltage, I already destroyed
one doing this. I added a low drop Schottky diode inline with the
positive supply to make it idiot proof, and it works. You might want
to do the same.
I printed out the encoder disks using a 64 stripe pattern that was
scanned out of "Mobile Robot, Inspiration to Implementation". If I
can count both the rising and falling edges of the pulse, that gives
me 64 ticks per revolution. I still haven't come up with the software
algorithm yet, but it looks like it's going to involve some PI or PID
control. I still have to get a pulse accumulator, still shopping
around but it looks like Al Williams PAK7 is the best one I've seen
so far. Good luck and keep me posted, if you solve the problem before
I do I'd love to see your solution. Best regards,
-Dave
--- In basicstamps@yahoogroups.com, "Bryan Smith" <bsmith@w...> wrote:
>
> I am working on the same problem. I just received the parts for the
> following article.
>
>
http://www.seattlerobotics.org/encoder/200010/dead_reckoning_article.h
tm
> l
>
>
>
Original Message
> From: nuclearspin2000 [noparse][[/noparse]mailto:nuclearspin2000@y...]
> Sent: Saturday, November 08, 2003 11:43 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Wheel encoding
>
>
> Hi All,
>
> I now have wheel encoders on my robot and am looking for ways to
turn
> the pulses they generate into useful information. My primary
interest
> for the moment is straight line tracking. Somedays my robot travels
> straight, somedays it drifts left and sometimes it will drift right
> (fickel servos). It's a constant, irritating problem and I'm
getting
> tired of having to recalibrate my pulses everytime I run it.
>
> So I'm wondering how other Stamp users have overcome this problem.
I
> was thinking of looking into the PWMPAL but I'm still not sure it
> will do what I need it to do. Thanks.
>
> -Dave
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject
> and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
www.rhombus-tek.com/SMt_Rob.htm
www.rhombus-tek.com/co-processors.html
The original testing had a BoeBot with 30+ segments per wheel completing
a perfect 'Square', reversing and returning home accurately.
As you have discovered, it is not just the distance, but the difference
in accelaration that matters.
David Lawrence
www.rhombus-tek.com
Original Message
From: nuclearspin2000 <nuclearspin2000@y...>
To: <basicstamps@yahoogroups.com>
Sent: Saturday, November 08, 2003 9:43 PM
Subject: [noparse][[/noparse]basicstamps] Wheel encoding
> Hi All,
>
> I now have wheel encoders on my robot and am looking for ways to turn
> the pulses they generate into useful information. My primary interest
> for the moment is straight line tracking. Somedays my robot travels
> straight, somedays it drifts left and sometimes it will drift right
> (fickel servos). It's a constant, irritating problem and I'm getting
> tired of having to recalibrate my pulses everytime I run it.
>
> So I'm wondering how other Stamp users have overcome this problem. I
> was thinking of looking into the PWMPAL but I'm still not sure it
> will do what I need it to do. Thanks.
>
> -Dave
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject
and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
>
>
>
frame.htm
--- In basicstamps@yahoogroups.com, "Bryan Smith" <bsmith@w...>
wrote:
>
> I am working on the same problem. I just received the parts for
the
> following article.
>
>
http://www.seattlerobotics.org/encoder/200010/dead_reckoning_article.
htm
> l
>
>
>
Original Message
> From: nuclearspin2000 [noparse][[/noparse]mailto:nuclearspin2000@y...]
> Sent: Saturday, November 08, 2003 11:43 PM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Wheel encoding
>
>
> Hi All,
>
> I now have wheel encoders on my robot and am looking for ways to
turn
> the pulses they generate into useful information. My primary
interest
> for the moment is straight line tracking. Somedays my robot
travels
> straight, somedays it drifts left and sometimes it will drift
right
> (fickel servos). It's a constant, irritating problem and I'm
getting
> tired of having to recalibrate my pulses everytime I run it.
>
> So I'm wondering how other Stamp users have overcome this problem.
I
> was thinking of looking into the PWMPAL but I'm still not sure it
> will do what I need it to do. Thanks.
>
> -Dave
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject
> and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
Thanks for the reply. Your control algorithm is very similiar to
others I've seen and is the one I'm going to try implementing first.
Is this just a paper design or did you actually implement it? What
part numbers did you use? Thanks.
-Dave
--- In basicstamps@yahoogroups.com, "rcrousseau" <rrousse1@s...>
wrote:
>
http://shrike.depaul.edu/~rrousse1/engineering/control/controlsystem_
> frame.htm
>
> --- In basicstamps@yahoogroups.com, "Bryan Smith" <bsmith@w...>
> wrote:
> >
> > I am working on the same problem. I just received the parts for
> the
> > following article.
> >
> >
>
http://www.seattlerobotics.org/encoder/200010/dead_reckoning_article.
> htm
> > l
> >
> >
> >
Original Message
> > From: nuclearspin2000 [noparse][[/noparse]mailto:nuclearspin2000@y...]
> > Sent: Saturday, November 08, 2003 11:43 PM
> > To: basicstamps@yahoogroups.com
> > Subject: [noparse][[/noparse]basicstamps] Wheel encoding
> >
> >
> > Hi All,
> >
> > I now have wheel encoders on my robot and am looking for ways to
> turn
> > the pulses they generate into useful information. My primary
> interest
> > for the moment is straight line tracking. Somedays my robot
> travels
> > straight, somedays it drifts left and sometimes it will drift
> right
> > (fickel servos). It's a constant, irritating problem and I'm
> getting
> > tired of having to recalibrate my pulses everytime I run it.
> >
> > So I'm wondering how other Stamp users have overcome this
problem.
> I
> > was thinking of looking into the PWMPAL but I'm still not sure it
> > will do what I need it to do. Thanks.
> >
> > -Dave
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
> Subject
> > and Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/