Older blog entries for cschur (starting at number 38)

Hi all,

Well, here it is - our first operational images and movies of our new robot arm/gripper on PAAMI. Right now, Im just showing you how it works, and how it will be used. The arm motor is slow right now to keep the arm from jerking when it lifts, and will be replaced with a standard servo which is on order. This is a great example of priority arbitration architechture. The highest level now is the Grab module, and subsumes the other levels when triggered.

http://www.schursastrophotography.com/robotics/paami8.html

Comments?

Chris comets133@yahoo.com

HI all,

Another update on PAAMI. We are on the last processor module we intend to implement, the can seek and grab module. Im using a PIC16F73, which has 22 inputs and a nice4 A/d inputs at 10 bits. Its also great because it will hold 8k of program memory. This will be the 12th parallel processor working in her. This weekend, I wired in the servos on the arm including the lift and grab motors, and got the new processor up and running. I was able to FOR THE FIRST TIME to have the robot reach out, grab a soda can and lift it and store it on its back. Pretty cool, ay?

Now heres the freaky part. I removed one of the two boards in the bot, and had it on the bench to add the new processor. But the other parallel processors were also powered up on that board, and were alive and thinking! While I tested power and voltages on the socket for the new processor, the dozen lights or so on the board were flashing, showing status and trying to drive the bot around! Oh man, thats kindof freaky working on a living AI....

Chris comets133@yahoo.com

HI all,

Exciting news - our last endeavor on PAAMI is to get the can lifing arm and gripper working. This weekend I added the lexan gripper, driven by one tiny servo, and the arm which is a pivoting horseshoe shaped bar that pivots over the top of the robot, over the beacon dome and lowers the gripper to the position the can is supposed to be in eventually. Im controlling it manually right now with a servo driver box, but after I refine the mechanism, which works darn well right now, Ill wire it to the motherboard and start the final level of subsumtion, the can grab and deposit level. Videos to come soon!

Chris Schur

HI all,

Here are some more IR images of the robot in the dark, You may be interested in the patterns projected onto the ground by the GP2D120 and 12 sensors:

http://www.schursastrophotography.com/robotics/dropoff2.html

Chris

We have finished our drop off sensor array for our priority arbitration bot, PAAMI this weekend. The final touch was to add two GP2D12 sensors on each side of the rear caster wheel with a small 12F675 PIC to convert the analog to digital and drive the IMPACT processor. The robot is programmed to go forward a short distance ballistically when the rear drop off sensor swings over the stairwell. You can either rotate your back wheel over the stairs and fall off, or back up over it. Either way, its doom. The other sensors were tilted out a bit on both sides of the main drive wheels to add some additional buffering to the dropoff. Finally, Ive done some IR imageing of the GP2D120 and 12 sensors light beam. You may find this intersting, and Ill post some images later on this week, but in essence, the beam diamter is pencil eraser sized in the first few inches, with a sharp edge. At 1 foot, its up to half an inch and by 2 feet up to an inch and becomming very diffuse.

Chris

Just a quick note, Im adding two GP2D12 sensors to the back bumper plate to PAAMI today, to watch if there is a drop off on either side of the rear caster wheel. The problem is when the bot rotates and it is next to or along side of a stairwell, the back wheel can fall over the edge, leading to rather disasterous results! the sensors are located about two inches on each side of the castor, and about an inch outboud toward the rear. The processor will be instructed to go forward if either of the rear drop off sensors sees anthing over a 2 inch fall off. Of course, since the sensors are analog, they need a/d converters. Once again the killer PIC12F675 chip comes to the rescue, and I can digitize the gp sensor output directly, and put out a hi low signal to the main impact subsumption processor to enact on the drop off. These cost less than a buk, compared to the GP2D sensors, which are nearly 10 buks!

Chris

Hi all,

We have added a new type of rear bumper design to our robot, possibly a design you can use in your robot as well. Its cheap, very effective and totally reliable. Id love to share it with you:

http://www.schursastrophotography.com/robotics/rbump1.html

Chris

Hi all,

I now have a web page for our current Priority Arbitration Bot, I wanted to wait until we got it far enough along to show something significant:

http://www.schursastrophotography.com/robotics/paami_main.ht ml

Chris

Hi all,

Here is the first write up on our testing of the prototype drop off sensor array. I hope you find it helpful:

http://www.schursastrophotography.com/robotics/dropoff1.html

Write me at

comets133@yahoo.com

Chris Schur

HI all,

Major progress last night on the drop off sensor array. We put four GP2D120 sensors on the robots bottom, about an inch in front of and behind the wheels. These route to two 12F675 PIC's which have the a/d converters, and are really cheap. Right now, I sample the sharp sensors, which are remarkably uniform and when a drop over 2 inches occurs on any of them, for now an LED lights. This will then be ported into the Bumper/Impact module which has a very high priority in the arbieter. Thats later this week. For now, I can push the bot over an overhang on a table, and the corresponding LED will light indicating the drop off. Will the robot be able to stop in time to prevent certain death? Stay tuned!

Write me:

comets133@yahoo.com

29 older entries...

X
Share this page