Robotic Claw Inspired By Doombot.

 
#11

This is a really good idea, with great progress so far. Clawed robots always struggle with knowing how and when they have actually grabbed the item they were designed to grab. Excited to see how your design progresses Smile

#12

This is what the claw has evolved into....


#13

Richard R ,
Claw actions looking good. Triggers respond well. What hardware are you using on shoulder and claw? Very smooth.
I like the aluminum framework. What kind of IRobot platform is it built on?
Looks like a tall robot.
I think the sneak preview turned into a great build.
Thanks for sharing.
Steve S

#14

Thanks Steve... sadly and even with the aluminum it was too heavy for the create base so I had to switch to a Zagros robot base I had. Still a work in progress and a crap load more programming is still needed. The shoulders are vex turntables with two vex 393 motors per shoulder. The arms are strong enough to easily lift a full bottle of beer without any idle back drive after lift. I am now using IR detectors in the claws to trigger closing when objects are near... I might work on an elbow joint if I can figure out how to do it without adding too much weight to the arm. Needs a animated head now too, any suggestions? Grin

#15

@Richard, here is a link to the Sharp optical ranger that I use on my robots claws etc.

www.pololu.com/product/1134

If you buy just the sensor alone its under 4 bucks, they are very small and work well.

www.pololu.com/product/1135

Hope this is of help.

#16

Thanks Tony, it does help... I am going to grab some today... Smile

#17

@Richard, I modify the Sharp Rangers tiny PCB so the red LED is visible from the front and I wire in the "enable pin" (blue wire) to a 4pin header connector, here is a photo of the mods.

User-inserted image

#18

@Richard , Those Vex Turntables are cool and look like they may help a lot of builders easily make movable joints. They sat they are made for high load but I wonder just how high. What kind of servo are you using to move them? Looks like the servo needs some type of gear attached that sticks down into the turntable to mesh with the internal gears?

@Tony , Your amazing. You find all the cool toys. Smile These sensors only tell when an object is within it's gaze not how far away it is. How do you let the robot know when the object is actually within the hands grasp area?

#19

I am using vex 393 motors (two per shoulder) and limit switches to prevent over rotation. The arm can lift 3lbs easily at 75% power (haven't tried heavier yet). I am using a sabertooth 2x5 motor controller to run the motors...I am now working in a elbow joint using a single motor and a jack screw assembly... Albeit slow, the elbow joint with a single vex269 motor can also easily curl a 3lbs weight... What geared dc motors lack in precision (compared to servos) they make up for in power.... Besides, with limit switches and coding I am doing a pretty good job of precision movements.... pics and more videos are coming...

Thanks for your comments
Richard

#20

@Dave, these object detection sensors flag the main controller when an object comes into range of its view. with the GP2Y0D810 the range is 100mm (4 inch) and with the GP2Y0D805 the range is 50mm (2 inch). There output is normally high and driven low when an object comes into range, so you just need to connect it to one of the EZ-B port lines. I use the 100mm type which senses outside of the fingers (they have to be slightly open) so a signal on this port line shows that something has been placed in front of the hand.