Let's Make Robots!

Cardboard Robot Series

Looks like cardboard...now it moves like cardboard too!!!

Original

So far all I have is this cardboard prototype. I chose to make it out of cardboard instead of making a CAD model cause I thought it would be FUN! :p

 

 

Well it's pretty obvious what it is...it's a robotic arm...and it's name is A.R.M. which stands for Autonomous Robotic Arm. It's perfect! I made the cardboard model in hopes that I could mount my servos inside of it...but I don't know how to attach a servo to cardboard. So I used thumb tacks instead. This is actually my second model that I made because the first one had dimensional problems and the servos couldn't rotate the full 180 degrees.

 

Plans for the future 0.o

 

When I finish this ARM project (which shouldn't take long,) There will be 3 translation joints (as with the model) but also a rotation joint at the base and a rotation and translation joint at the wrist before the gripper. The ARM will use machine vision to track objects that it wants to grab. Using a camera (probably CMUcam) the arm will be able to distinguish between different color objects and will be able to track them using middle mass detection. The body will be made up of HDPE and I'll probably be using standard servos, but I haven't done any force calculation yet. Using the input from the camera as well as varies distance sensors, the arm will use simple reverse kinematics to mathematically determine how to reach the target. I'll probably use the Arduino at first to get everything working, and then simply use an AVR ATMEGA-168 by itself.

 

After the ARM project, I plan on building a simple 4WD platform on which it can rest. The Camera (not shown) that will be mounted on the ARM will (hopefully) be use for obstacle detection when the ARM is not in use.

Simple 4WD robot

 

That's about it for now. If anyone has some cool idea for this poject or have any questions, let me know...

 


 

UPDATE 01.18.09 0420

Upon further consideration...I chose to complete the cardboard model!

Cardboard arm with servos glued in!

 I hot glued in the servos (first I tested it to make sure I could get the glue off...thanks Oddbot)

 34ebwuv.jpg

There I mounted it into a cardboard box with the front and sides cut off but left a small portion in the middle to glue the shoulder servo on.

 Top View

Here you can see how the joints are set up, they're all the same. You can also see the Arduino over there, and the crappy breadboard because I don't have any headers :'(

 Now I just have to program it and a video will be up ASAP!

 


UPDATE 01.18.09 0533

 

VIDEO VIDEO VIDEO! But you probably aready knew that because it's up there and not down here because I don't know how to get it down here....but o well. Just watch!

 As of now, each servo is being controlled in unison by the code, meaning that they're not hooked up using a Y adapter or anything like that, they're all just getting the same PWM signal from the Arduino.  I'll be writing new code that will allow full control over each servo soon.

 I'm guessing that the servo for the shoulder joint is pumping out max amps....so I'll need a stronger one there...especially since the real one won't be using cardboard....the other ones seem to be fine, but I still need to do calculations.

 

P.S. Sorry the video's so awkward...I'll try to get a better one up tomorrow...or rather, later today....it's 0648 and I've been up for a while....

 

 


UPDATE 01.18.09 1712

 

Thanks to Oddbots' suggestion, I decided to create this:

2mdjupk.jpg

it's a cardboard robotic catapiller (thanks to oddbot who gave me the idea). A video will be posted as soon as YouTube is done processing. It was my robotic arm, but I took off the shoulder joint and then attached the circuits using rubberbands. I also added homemade washers because the more you work with cardboard, the more it tears. 

Plans for the future 0.o

I plan on making this a full fledge robot as well. I'll use HDPE to make the body (which will be more effecient at moving thanks to rubber grips I'll be adding) and I'll use sub-micro or micro servos for the control...so it will be small...and cute...and FUN!

 I decided to change the name to Cardboard Robot Series because it's no longer an A.R.M. project, it's cardboard robot projects!

Maneuver said the following:

"Daring to take a differnt approach and going for "fun" over "practical" is what will spawn new ideas."

and obviously, he's right!

 

 


UPDATE 01.18.19 1815

 

VIDEO!

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I love it. It makes me laugh. Like to see what it turns into
More of an inch worm I think though the way it moves. :) Nice job on the arm and inch worm. Cant wait to see the finished product. It reminds me of transformers. Robotic arm transforms into robotic inch worm W00T!. :P

A Cardboard Mind Is A Joy For Ever!

And obviously: "Every Robot Need A Hat!"

As an afterthought, you may want to consider putting your servos on a seperate supply so they don't burn out your Aduino's regulator. Under heavy load any one of those servos is capable of overloading your regulator which probably has a 1A limit.

See this tutorial for some alternative power configurations. Your Arduino already has the 5V side covered but you should try and run your servos from the battery without exceeding their 6V limit.

Yeah I know that pretty much a rule when it come to robots, however, I just expect this to be a quicky prototype so I wasn't worried about it.

That was a great start, probably need to add some weight at the front and put the third servo in the middle so that it can twist if you continue with th catterpilla idea. Maybe some adheasive velcro strips or suction cups for traction?

If you do want to make an arm then to overcome the strength problem you might be better off with some motor/gearbox assemblies that are much stronger and then mount pots in the joints for positional feedback. See Frits's tutorial on home made servos.

Another arm suggestion is to have the control servos all at the shoulder with cables attaching them to their joints. This means the arm doesn't have to lift the weight of all those servos, just strings or belts and some pulley wheels.

...And C.R.S. means something different where I come from...

When I was designing Walter's head, I thought about an arm instead of the x,y,z I have now...  Of course I was looking at the cool servo driven arms available in the 300 to 400 dollar range. It was then that I really found out about servo torque. And here is what I found... Servos are weak. A standard servo is rated between 40 and 60 oz/in which means at 1" from the pivot, it can lift, say, 50oz. Now lets stick a 4" arm onto that leading to the next joint. Now we have 50/4 = about 12 or so. Add another servo at that joint and we loose about an oz and we are about down to 10 oz it can lift. Add another 4" section and a servo on top of that and you are soon to the place where your arm can't even lift itself. On the arms I looked at they were using (2) high torque servos at the bottom and elbow minium. I did some looking and it seems better to use one 1/4 scale servo for the base, hi-torque for first and second joints and standards and mini's from there.

Hope this helps, all I am saying is when I did the math, it got expencive quick.

 

hhhmmmm....oh yeah....I forgot that money exsisted....damn.

I never really thought about cost, but seeing how that's a big factor I'll stick with my $8.99 servos and cardboard haha.

 

-Thanks

How much are you feeding them servos? Seem very aggressive?! (Which is nice - IMHO all servos are too weak, pussies!)

(Yes, I know you can get expencive ones)