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DPRG: Re: Robot platforms

Subject: DPRG: Re: Robot platforms
From: Wade A Smith warm38 at juno.com
Date: Fri Mar 5 19:22:18 CST 1999

Again, I forwarded my email to Kam also and here is his response:

Good stuff for someone warped as me.   8-)

- --------- Begin forwarded message ----------
>From: Kam Leang <kleang at eng.utah.edu>
To: Wade A Smith <warm38 at juno.com>
Cc: dprglist at dprg.org
Subject: Re: Kam Leang <kleang at eng.utah.edu>: Re: Robot platforms
Date: Fri, 5 Mar 1999 12:36:38 -0700 (MST)
<Pine.GSO.4.02A.9903051132390.19607-100000 at lab1-12.eng.utah.edu>

- -->DPRG People, 
- -->
- -->I forwarded a message from SRS, the guy responded to me and then
- -->I got this from him.  He asks some questions.  What do you think?
- -->He's not on the email list, so cc him with your response.
- -->
- -->My personal preferance is a tank base.  I currently have the
- -->Tamiya King Tiger as my robot base, but I'm always still looking
- -->for "the ultimate" tank base -- shucks, I even drool over turing
- -->one of those little pipe trenchers with the tracks 9" hi and 3' long.
- -->Can you imagine what kind of mondo robot THAT would be?  But the 
- -->wife would probably not like to see it running around in the house. 
- -->I did buy a large plastic "tank" from Target (made for a 12" action
- -->figure).  I gotta find some geared motors that fit within the 5"
- -->space available to connect to the drive sprocket (which will need to
- -->be homemade since all the wheels were the same -- no matter if road 
- -->wheels, idler and drive sprocket).  Any "GOOD IDEAS" for sources of
- -->motors that will fit in 5"wide x 4'hi x 18" long????
Tank bases have been one of my favorites.  I've built a couple already
my most recent one "Commando" was made from a Tamiya Twin Motor gearbox
set.  You can pick them up for about $15 from http://www.robotstore.com
I've been using the gearbox set for a couple of years now and have
had great success.  I'm a teaching assistant for a course called
Mechatronics and the students are required to build a robot each year.
Basically, this is my testing ground.  I've used a bunch of different DC
motor gearbox sets from Tamiya and I highly recommend them as long as a
proper motor driver circuit is provided.  They aren't the most efficient
motors.  The standard motor driver circuit that we use is either an
H-bridge or a bipolar push-pull circuit.  I posted the circuit in the
Handy Board website if anyone is interested.

Edmund Scientifics sells a variety of gearbox sets as well. If
take a look at http://scientifics.edsci.com/  The difficulty I had with
Commando robot was the track pulleys.  I bought a cheap Tonka tractor toy
for about $11 and ripped out the pulley wheels and treads.  Mounting the
pulley wheels required some machining, so I made bearing motor shaft
mounts for the wheels.  That was the most time consuming part of the
robot.  Tank tread drive tends to be high on the friction list so I used
the bearings to reduce the torque required by the Twin motor gearbox to
get the robot moving, otherwise poor O Commando would have been a paper
weight!  Kid toys are a great source of parts for robots, but custom
machining is usually required to get what you want.  There are companies
out there that sell timing belts and pulleys for tank treads.  Try to
for them from http://www.wmberg.com  http://www.smallparts.com  but be
aware because they can be pricey.  

If the Tamiya motors aren't your style and you want more precision and
performance, then I would recommend http://www.micromo.com  or
www.servosystems.com They are more expensive.

So, considering what I've said above I think it would be nice to have
standard tank platforms or other robot platforms available and at the
prices as possible.  Building robots should be fun.  So any comments
the tank platforms or other platforms that would be of interest?  I'm
to suggestions and would love to here the pros and cons.

Thanks for you time and good luck with all future robot projects.  Again,
thanks Wade for promoting the interest!
- --kam

- -->In Japan they had a robot in 3 tracked segments for finding people in
- -->caved in buildings.  Now THAT was a cool tracked robot!  Also mucho 
- -->pricey.
- -->
- -->wade
- -->
- -->--------- Begin forwarded message ----------
- -->From: Kam Leang <kleang at eng.utah.edu>
- -->To: Wade A Smith <warm38 at juno.com>
- -->Subject: Re: Robot platforms
- -->Date: Thu, 4 Mar 1999 21:53:59 -0700 (MST)
- -->Message-ID:
- --><Pine.GSO.4.02A.9903042135070.19607-100000 at lab1-12.eng.utah.edu>
- -->
- -->Hi Wade!
- -->Yes, I agree.  If I get more interest then I'll be sure to design
- -->Also, I want input from robot builders about the platform specs.  What
- -->are
- -->robot builders out there looking for?  I've been building robots for a
- -->few
- -->years now and I also teach a course that involves building an
- -->robot so I've got a good idea of what to design, but still need a bit
- -->input.  I don't want to design something that's not going to be used.
- -->Also, my goal is to build it as cheap as possible.  I know how
- -->things can get after you consider batteries, MCUs, mechanisms,
- -->etc.  If you look at the prices I offer my kits at, they are as low as
- -->can go.  I'm breaking even--I hope!
- -->
- -->Here's a few ideas I had in mind for future platforms.
- -->1.  I want to design a tank robot base that is either servo motor
- -->or DC motor driven.  What do you think?
- -->2.  I want to design a small base similar to my Minibots.  Have you
- -->them yet on my site?  http://www.mech.utah.edu/~kleang  Anyway, there
- -->seems to be an increase in interest related to small robots.  The
- -->Minibots
- -->will be small enough to fit a Botboard or Basic Stamp and have layers
- -->expansion.  I've got the design already.  All I need to do is have
- -->parts made so I can sell it as a kit.
- -->3.  Large robot base that can accomodate bigger motors and perhaps a
- -->laptop.  I've seen the ones out on the market today and would like to
- -->my own.
- -->
- -->These are just a few ideas off the top of my head and I have more.  I
- -->also
- -->want to design sensor mounts for such sensors as the Polaroid sonar
- -->sensor, IR light sensors, etc.  Also I think there's a need for servo
- -->motor mounts.  It's a pain to mount servo motors to a flat base, but
- -->there's just a simple mount that can be easily attached to the base of
- -->flat platform for a few bucks, I'm sure that it will help out a lot of
- -->robot builders.  Also I'd like to design a few gripper mechanisms that
- -->require either one or two servos.  They should be simple and robust
- -->be
- -->easily fitted to almost any existing system.  In addition, I'd like to
- -->move into custom robots where the robot builder can log on and choose
- -->parts he/she wants on their robot.  Everything from the wheels to the
- -->sensors and have them all shipped out ready for assembly.  
- -->
- -->There's plenty of ideas.  I'm just waiting for interest.  It's hard to
- -->invest without knowing if it's going to be used.  
- -->
- -->Any comments on this?  kam
- -->
- -->On Thu, 4 Mar 1999, Wade A Smith wrote:
- -->
- -->-->
- -->-->On Thu, 4 Mar 1999 07:52:07 -0700 (MST) Kam Leang
- --><kleang at eng.utah.edu>
- -->-->writes:
- -->-->>Hi Wade,
- -->-->>Thanks for sending to the DPRG!  I appreciate the exposure.
- -->-->
- -->-->Hey, I know lots of them are interested in a robot base, so why not
- -->-->give them more of a choice?
- -->-->
- -->-->>Good luck with your robot projects.
- -->-->>kam
- -->-->
- -->-->thanks.
- -->-->
- -->-->wade
- -->-->
- -->-->___________________________________________________________________
- -->
- -->
- -->                \\\|///
- -->                (     )
- -->                \ @ @ /
- -->*-----------oooO--(_)--Oooo------------*
- -->| Kam Leang                            |
- -->| University of Utah                   |
- -->| Department of Mechanical Engineering |
- -->| MEB Room 2202                        |
- -->| Salt Lake City, Utah 84112           |
- -->| (801) 581-3140  Fax: (801) 585-9826  |
- -->| http://www.mech.utah.edu/~kleang     |
- -->*-----------------------Oooo-----------*
- -->              oooO      (  )
- -->              (  )      ) /
- -->               \ (     (_/
- -->                \_)               
- -->
- -->
- -->--------- End forwarded message ----------
- -->
- -->___________________________________________________________________
- -->You don't need to buy Internet access to use free Internet e-mail.
- -->Get completely free e-mail from Juno at
- -->or call Juno at (800) 654-JUNO [654-5866]
- -->

                (     )
                \ @ @ /
| Kam Leang                            |
| University of Utah                   |
| Department of Mechanical Engineering |
| MEB Room 2202                        |
| Salt Lake City, Utah 84112           |
| (801) 581-3140  Fax: (801) 585-9826  |
| http://www.mech.utah.edu/~kleang     |
              oooO      (  )
              (  )      ) /
               \ (     (_/

- --------- End forwarded message ----------

You don't need to buy Internet access to use free Internet e-mail.
Get completely free e-mail from Juno at http://www.juno.com/getjuno.html
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