go_away

Author Topic: my first robot: Dr. Claw  (Read 2709 times)

0 Members and 1 Guest are viewing this topic.

Offline WhomBomTopic starter

  • Full Member
  • ***
  • Posts: 64
  • Helpful? 0
my first robot: Dr. Claw
« on: September 02, 2009, 02:24:35 PM »
I'm proud to present my first robot to you,

After reading a lot on the forum and tutorials i decided to give up on my six legged insect idea and make a differential drive version. I used an Arduino duemilanove for brains and 7,2V battery packs from a RC car. I removed one of the cells from these packs to make them 6V. I had to order the wheels, sensor and servos but the rest was all dug up somewhere as scrap. Because i never programmed before, except a little bit in basic, it took me at least 15 versions to get the program right. Although i still want to make the program better because it now immediately acts on what it sees and i want it to first take a good look around and then act on what it just saw. I think i need to store my data in an array for this but i don't know how to do that yet. What it does now is look from right to left and if it sees anything drive to it and eventually when it is close enough, bite. Once i find a program to convert my video files i'll post some vids right now i only have a couple of pics, and shitty ones too...  :-[





It drives really well, it can handle gravel and an uncut lawn.

Offline WhomBomTopic starter

  • Full Member
  • ***
  • Posts: 64
  • Helpful? 0
Re: my first robot: Dr. Claw
« Reply #1 on: September 07, 2009, 02:16:35 PM »
here are some vids  :)

Dr. Claw searching

Dr. Claw attacking


This is basically all it can do right now. I've added some switches in the claw so it can feel if it actually gripped anything (or so i hope). I have a PIR sensor, but i'll install this once it is completed.

Things to do include:
 adding a sonar to the head for increased range en broader detection of objects,
 adding a thermal sensor so that it only attacks things that are 37 C
 trying like hell to make it smarter, actually i think this is where i'll spend most of my time since i'm a mechanical guy with an interest in electronics rather than a programmer....

But since school hast started again i think it will take a while before everything's completed, and the fact that i blew up my servo for the head an hour ago also doesn't help much...

Offline Joker94

  • Supreme Robot
  • *****
  • Posts: 1,119
  • Helpful? 26
Re: my first robot: Dr. Claw
« Reply #2 on: September 08, 2009, 04:49:05 AM »
great bot, coming along nicely

can't wait to see the other sensors intergrated ;D

Offline SmAsH

  • Supreme Robot
  • *****
  • Posts: 3,959
  • Helpful? 75
  • SoR's Locale Electronics Nut.
Re: my first robot: Dr. Claw
« Reply #3 on: September 08, 2009, 05:36:41 AM »
those chompers are nice ;D
any idea of the pressure they are capable of?
Howdy

Offline WhomBomTopic starter

  • Full Member
  • ***
  • Posts: 64
  • Helpful? 0
Re: my first robot: Dr. Claw
« Reply #4 on: September 09, 2009, 04:48:01 PM »
thanks  :)

That's quite a question, i have no idea. I'll have tot test it! Al I can say is the servo should have 10kg/cm torque,


this is how the claw works, the fork (grey)  is attached to the servo arm 3cm from the middle, so in worst case it pulls the fork with 3,3kg. around 180 deg. servo rotation the force on the fork can be much much bigger because effectively the length of the arm is decreasing (cos(a)*3cm). When the servo is at 90deg a =0 at 180 deg it is 90. cos(90) = 0 so theoretically is should have infinte force  ;D

the distance between the pivot of the claws and where te rods connect is 2cm, if is disregard the rods not being in line with the fork that in worst case leaves me with 1,15kg *2cm = 3,3kg/cm torque on each claw.

the middle spikes of the claw are 4cm from the pivot so at these spikes the pressure should be about 550grams, imagine a pint standing on your hand, on a screwdriver.

the outer edges of the claw are 8cm from the pivot so here it is only 275grams, but the inner spikes are just 2cm out so here it should be 1,15kg. I can tell you it really pinches if you put your finger in there, but pracically nothing ever gets between those points because it's too narrow.
« Last Edit: September 09, 2009, 04:50:26 PM by WhomBom »

Offline ceruleanplains

  • Full Member
  • ***
  • Posts: 57
  • Helpful? 0
  • Got Wumpus?
Re: my first robot: Dr. Claw
« Reply #5 on: September 11, 2009, 12:07:42 PM »
have you tried crushing cans?

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,658
  • Helpful? 169
    • Society of Robots
Re: my first robot: Dr. Claw
« Reply #6 on: September 12, 2009, 05:53:16 PM »
lol nice! :D

and crush a can, please! do you by any chance have a kitten?

Quote
servo rotation the force on the fork can be much much bigger because effectively the length of the arm is decreasing (cos(a)*3cm). When the servo is at 90deg a =0 at 180 deg it is 90. cos(90) = 0 so theoretically is should have infinte force
I think you need to do that math again . . .

Offline WhomBomTopic starter

  • Full Member
  • ***
  • Posts: 64
  • Helpful? 0
Re: my first robot: Dr. Claw
« Reply #7 on: September 13, 2009, 04:14:43 PM »
It can't crush cans   :( at the outer tips of the claw it can dent a reb bull can. The can is ab bit square shaped, but not crushed.. 

And yeah, it should be sinus instead of cosinus  :-[  i also made a mistake in the 3cm of the arm, it's actually only 1,5cm

Offline radhoo

  • Full Member
  • ***
  • Posts: 66
  • Helpful? 1
Re: my first robot: Dr. Claw
« Reply #8 on: September 14, 2009, 03:45:26 AM »
very nice.

you could add a camera-flash circuit, and connect the discharge capacitor one terminal to each of the two claws.

it would give you an electrical strike :), nice for cans too.

Offline WhomBomTopic starter

  • Full Member
  • ***
  • Posts: 64
  • Helpful? 0
Re: my first robot: Dr. Claw
« Reply #9 on: September 14, 2009, 05:01:31 AM »
That wicked thought crossed my mind too  ;D i have an old insect killer (those blue lamp things that zap flies) lying under my bed...

But i only want to do that once it's completely finished.

Offline radhoo

  • Full Member
  • ***
  • Posts: 66
  • Helpful? 1
Re: my first robot: Dr. Claw
« Reply #10 on: September 14, 2009, 07:58:20 AM »
cool.

not to mention flame throwers or other toys  :D

Offline m4nti

  • Jr. Member
  • **
  • Posts: 27
  • Helpful? 0
Re: my first robot: Dr. Claw
« Reply #11 on: September 26, 2009, 10:00:04 AM »
that's one mean sob lol

Offline c02cutter

  • Jr. Member
  • **
  • Posts: 24
  • Helpful? 1
Re: my first robot: Dr. Claw
« Reply #12 on: September 26, 2009, 10:08:17 AM »
Nice bot, ought to turn it into the smarter mouse trap.

Offline galannthegreat

  • Supreme Robot
  • *****
  • Posts: 615
  • Helpful? 4
  • Blue-Lensed Blue LEDs?! What?! Impossible!!
Re: my first robot: Dr. Claw
« Reply #13 on: September 26, 2009, 12:36:27 PM »
Wow, great job on the 'bot!
Kurt

 


Get Your Ad Here