Author Topic: New RC robot project (Read 8652 times)

garriwilson · « **Reply #30 on:** December 19, 2007, 06:46:34 PM »

Sorry for this noob question: When using a jigsaw, where do you put the material you are cutting? Is there supposed to be a hole for the blade to go through? Where do I put the HDPE? A table?

airman00 · « **Reply #31 on:** December 19, 2007, 07:01:05 PM »

You just clamp it to the table, with the part you want to cut sticking off the table. Make sure the HDPE is clamped tightly. Turn the jigsaw on and then just cut the piece of the HDPE you want cut. You should probably buy work gloves to not cut your finger off

BE CAREFUL WHEN USING POWERTOOLS!

No hole, its just slicing across the plastic in the shape you make

seriously, do not cut off your fingers ., be super careful

garriwilson · « **Reply #32 on:** December 19, 2007, 07:09:43 PM »

When I'm designing my robot, how do I know how I should put the caster. I mean so it's at the same level as the drive wheels? I'm getting these wheels: http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXB913&P=0
Dave Brown Lite Wheels 4" in diameter (outside)

Also, I want to use an omniwheel as a caster for this robot. You know those small wheels on wheelchairs? And those metal attachments that connect the wheels to the wheelchair. What are those connections called? I want to get a small version of that, to attach the omniwheel to my robot so it can swivel.

Thanks

airman00 · « **Reply #33 on:** December 19, 2007, 07:18:04 PM »

you have to make a 3D model to scale

get the measurements for everything and then figure it out

an omniwheel is this

a swivel caster is this

a ball caster is this

What type of surfaces do you expect the robot to go on?

By the way, I used those same wheels before. Get a long servo screw from servocity to mount those wheels.

garriwilson · « **Reply #34 on:** December 19, 2007, 07:27:02 PM »

OK, I'm getting a swivel caster then.
I know I added those screws already to my cart.
I expect it to go on everything.

(carpet, concrete, dirt)

By the way I just found this really good tutorial on How to Use a Jigsaw:

http://www.rd.com/content/openContent.do?contentId=18223

garriwilson · « **Reply #35 on:** December 19, 2007, 07:39:32 PM »

Is this caster good from McMaster.com

Casters
This product matches all of your selections.

Part Number: 9950T51
$12.22 Each
Capacity
   225 lbs.
Mounting Type
   Plate
Caster Type
   Swivel
Wheel Material
   Rubber
Floor Material
   Asphalt and Brick and Ceramic Tile and Concrete and Dirt and Hardwood and Linoleum and Ribbed and Steel and Terrazzo
Wheel Diameter
   3-1/2"
Wheel Width
   1-1/4"
Mount Height
   4-3/4"
Rubber Wheel Material
   Rubber on Polypropylene
Plate Length x Width
   3-5/8" x 2-7/8"
Plate Thickness
   1/8"
Center-to-Center
   1-3/4" x 2-15/16"
Slotted to
   Not slotted
Bolt Hole Size
   11/32"
Frame Material Type
   Steel
Frame Construction
   Cold Formed and Heat Treated
Frame Finish/Coating
   Zinc Plated
Application
   General Purpose
Swivel Construction
   Rivet Kingpin
Kingpin Diameter
   1/2"
Wheel Bearing Type
   Ball
Swivel Bearings
   Double Ball
Leg Thickness
   3/32"
Axle Diameter
   3/8"
Axle Construction
   Solid
Specifications Met
   Not Rated
Wheel Bearing Features
   Debris Guards
Wheel Durometer Range
   Hard
Wheel Durometer
   70A
Wheel Color
   Gray
Number of Wheels
   One
McMaster-Carr Name
   Hammin
For Compatible Rigid Caster, Order:
   9950T52
For Field-Installable Face Wheel Brake, Order:
   2877T81

airman00 · « **Reply #36 on:** December 19, 2007, 07:46:26 PM »

nice find with the jigsaw info

that caster is huge!, way way to big

you want a smaller one , rated for about 15 pounds

garriwilson · « **Reply #37 on:** December 19, 2007, 07:51:41 PM »

I can find that at McMaster right?

airman00 · « **Reply #38 on:** December 19, 2007, 07:55:26 PM »

probably , for all terrain you probably need a six wheel robot , an insect robot, steering ( like a car) , or tracked vehicle.

forget all terrain for now, just do it for indoor use

for indoor use, a ball caster is fine

and for outside you need suspension......

garriwilson · « **Reply #39 on:** December 19, 2007, 08:09:02 PM »

I got confused at McMaster, so I went to Towerhobbies.

This is the only ball caster I found and there are no measurement specifications.

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXWB21&P=7

Admin · « **Reply #40 on:** December 19, 2007, 08:10:26 PM »

Quote

When I'm designing my robot, how do I know how I should put the caster. I mean so it's at the same level as the drive wheels?

CAD it up!

As for caster wheels, go to Homedepot and ask.

garriwilson · « **Reply #41 on:** December 19, 2007, 08:11:27 PM »

Just found this but again no specs:

http://www.pololu.com/products/tamiya/0066/

airman00 · « **Reply #42 on:** December 19, 2007, 08:26:00 PM »

yes, ordered that one for my robot in the tutorial

If you are patient enough to wait until next Tuesday , specs will be posted for that caster , as well as how to mount it , etc.

also, that caster is for smooth surfaces( or mostly smooth) its basically a (relatively) low friction skid.

garriwilson · « **Reply #43 on:** December 19, 2007, 08:28:27 PM »

I mean I want it to go on carpet, because my house is covered in carpet. However, I could live with just concrete and stuff. (outside)

Is there a caster that can go on carpet and asphalt?

david_or_johnny · « **Reply #44 on:** December 19, 2007, 09:58:58 PM »

Make your own with two pieces of sheet metal and a Dubro 1.5 in foam tailwheel

garriwilson · « **Reply #45 on:** December 19, 2007, 10:04:35 PM »

Omni-wheels work on carpet and asphalt right?

ADMIN, in your Experimental Robot Platform, how did you attach the omniwheel to the chassis? A metal rod axle?

Also, is 4" too big for wheels?

Admin · « **Reply #46 on:** December 19, 2007, 10:17:07 PM »

The concept of an caster is to have as low friction as possible.

Quote

ADMIN, in your Experimental Robot Platform, how did you attach the omniwheel to the chassis? A metal rod axle?

check out the last four images on this page:
http://www.societyofrobots.com/robot_mobot_2007.shtml

I reused the same exact parts from this line following robot on the ERP. The rod was plastic and press fit between two plates with holes. You will also find an interactive CAD of it on that page, just rotate the robot to see the bottom.

garriwilson · « **Reply #47 on:** January 02, 2008, 10:19:52 PM »

Why can't I attach a CAD of my robot? I think it says it's too big. Are CAD files too big to attach? How should I post it?

airman00 · « **Reply #48 on:** January 03, 2008, 05:40:46 AM »

if u used google sketchup export it as an image file. Then upload it

garriwilson · « **Reply #49 on:** January 03, 2008, 08:59:17 PM »

Trying that right now in this post.

airman00 · « **Reply #50 on:** January 03, 2008, 09:30:44 PM »

Very nice CAD!!!!

Are you sure that it is to scale?

garriwilson · « **Reply #51 on:** January 03, 2008, 09:32:39 PM »

Quote

Very nice CAD!!!!

Thanks, in fact it is my first fully done CAD.

Quote

Are you sure that it is to scale?

You know, I think I need to double check it. But most of it is to scale.

I will post more when I make changes.

airman00 · « **Reply #52 on:** January 03, 2008, 09:34:37 PM »

Next step: Buy / make the parts

Though I suggest you make another dedicated thread for the actual building of this new project

garriwilson · « **Reply #53 on:** January 03, 2008, 09:55:33 PM »

Well..., actually the next step is make some money. (~350$)

Caduscus · « **Reply #54 on:** January 04, 2008, 08:58:01 PM »

try checking out www.popsci.com they have a DIY project for something exacly like that, with places to buy the stuff and everything, I think it's called RC tank or something it's really neat

garriwilson · « **Reply #55 on:** January 05, 2008, 11:32:08 AM »

Is this what you mean: http://popsci.typepad.com/how20blog/2007/10/build-it-the-al.html

You know what, you gave me the idea to use a tank for chassis. I mean then I don't have to buy the radio equipment.

Thanks!

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Author Topic: New RC robot project (Read 8652 times)

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