My first omniwheeler

Let's Make Robots Robots
1

Update: Hmm.. I found that it pulls a trailer really well.. Hmm.. And the Omni's are really easy to navigate. Hmmm :)

I was waiting for my omni wheels to arrive, because I wanted to see if they where not the right thing for my main project.

While waiting and working on other small stuff, I got interested in making my own Mecanum Wheels.

After making that proof of concept, I decided to make 4 stable ones, and put them on a test-platform.

I got some triangled wood, drilled holes in it, and cut it in 64 pieces..

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Double sided tape on;

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Marked up 4 CD's:

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Metal sticks in the holes, wheels on..

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Till I had 4 wheels - of the homemade "Mecanum Wheels" - type:

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Made 4 continous servos, and glued the wheels up on them:

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...

 

 

And THEN I got mail:

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WHAM! To hell with homemade wheels, I am back on testing for my main project :)

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Really fast made, as you can tell, I stuck new wheels and some sensors and an old picaxe 28A board on the simple frame.

Made some code very fast one evening (atached, read it, it's short compared to how complex it performs), to test how to navigate with the setup of these interesting wheels..

Result & what I learned:

Really fun & effective, wicked fun to code omni! - check code. Info: servo passive is at 135, not 150, because I set them up with another controller.First commands, "servo" is just to initiate servos, they are set for real by the "servopos" commands

I think I may have to make more tests (read: Have more fun with new wheels) before moving on with the project :)

 

Sorry it's no fantastic robo-post, but it is & was my first omniwheeler, a simple robot, but I had to post it because the moves are new :D

(Have to clean up my workshop now, I know, a mess, must clean up!)

  • Actuators / output devices: 4 servos
  • Control method: undefined
  • CPU: Picaxe 28A
  • Operating system: Picaxe
  • Power source: 4 DD cells, 4 AA calls
  • Programming language: Picaxe basic
  • Sensors / input devices: Maxbotix EZ2
  • Target environment: indoor
This is a companion discussion topic for the original entry at https://community.robotshop.com/robots/show/my-first-omniwheeler
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Looks great fritz : )
Looks great frits : )

3

Nice! Is it able to slide to
Nice! Is it able to slide to the sides since it has the omni wheels? What was the benefit of using them above regular wheels?

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looks good! :slight_smile:
looks good! looking forward to see what will it do!

and… am I seeing another bot behing this one?? :slight_smile:

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thumbs up

thumbs up

6

Attachment
Nice. Don’t see the advantage over fixed wheels in this application, though. Are those the 2in wheels with the 1/2in hole? How’d you attach them to the servos?

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If you don’t see the

If you don’t see the advantage over normal wheels in this one, have a look at how the bot actually slides when turning. Would be impossible to do with normal ones. There is a close up of wheels at 1:27, effordsly it is made… normal wheels would take a lot of efford :slight_smile:

The wheels are just placed on the servos discs… with hot glue between the two surfaces :slight_smile:

I dare you to copy the project with normal wheels, the steering is quite outstanding - if you can see it or not :stuck_out_tongue:

8

it’s a way to lower friction

it’s a way to lower friction when the robot have to turn

the drawback is no control over side slip

anyway it’s a very appreciable show

9

"no control over side

"no control over side slip"?!?

What do you mean, like when on a roof of a building, or driving really fast and turning… or ?!?

10

yep precisely, obviously

yep precisely, obviously it’s not stable versus any sort of side force if compared to regular wheels…

it’s not a criticism :wink:

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No worries if it is / was

No worries if it is / was criticism, even if it was, I could take it :slight_smile: And if I sound harsh never mind it etc :slight_smile:

However, I would not give a f*ck if the robot should slide on a roof; It’s like “it could not take rain” or “it would not be able to drive in the snow”… Completely irelevant, it is driving inside, on flat surfaces, so what does it matter, why is it relevant?

Also, it is not able to drive very fast, so why bother about drifting at high speeds?

 

It is an indoor robot, driving on my flat floors, at the speed it can, and that is all the design should concentrate about, not zero gravity or sailing ships etc :slight_smile:

12

I see it

It’s like skidsteer, but without the disadvantages of skidding!

Pity there’s no sideways friction.I have a suggestion. I think if you make two wheels on teh same side just be regular wheels, you have a solution to the problem. You still have the advantage of skidsteer with no skid, but also the sideways traction.

That way, it would be able to drive sideways across a roof in the rain or the snow. :slight_smile:

13

Yes, you are right; if I

Yes, you are right; if I wanted to make sure it should not slide off a roof, I could glue one front and one rear wheels omni-thingeys, and still sort of turn well.

I could also use belt tracks.

Or hire someone to flatten the roof.

Yes.

You may think it is a pity that there is no sideways friction. But there is. It takes quite a push to make it slide sideways. And nobody is pushing it, and the floor is flat, you techies, so it is allright as it is.

Really, it does not slide to the sides unless I ask it to, by only moving front or rear wheels in a zig-zag motion.

Luckely, I want a robot to drive just as this one is driving, so there is really no problem!

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Hey, I just tested; It takes

Hey, I just tested; It takes so much tilting of the surface that even the Yellow Drum Machine is starting to slide it’s yellow tracks - before the omni-cousin does it.

Let it be known; Sliding is not a problem for this robot!

15

Eh?


There has to be some sort of misunderstanding here. Unless the laws of physics are different in Fristy land. You have four wheels with sideways facing rollers. What stops it sliding sidweays?
16

man thats flippin

man thats flippin awesome!

 

love it, nice work

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Q: "What stops it sliding

Q: "What stops it sliding sidweays?"

A: The lack of sideways force!

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I love Frits answers. They
I love Frits answers. They are so scholarly! Do you have a masters in physics?

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masters degree
in Sideways

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(the lack of it)BTW; It’s

(the lack of it)

BTW; It’s the same (lack of) force that keeps BOA off the wall most of the time!