Older blog entries for cschur (starting at number 83)

HI all,

Just finished a huge project, our article on Bumper Logic. If you have any interest in programming and implementation of a bumper based robot, this article may be of interest:

http://www.schursastrophotography.com/robotics/bumperlogic.h tml

Thanks for looking.

Chris

Let me know what you think: comets133@yahoo.com

Hi all,

Were almost done with our current project, to develop a bumper logic processor for future robot projects. We have now put the picbot II through everything from mazes, tunnels, dead ends, tons of corners, and other obstacles such as edges to develop a write up on a generic bumper chip. The article is nearing completion, I have many illustrations to do on it yet. And ill post the whole research paper here for you to evaluate. Here is the first intro paragraph as a teaser:

 eBumper Logic‍

Usually, the first sensors the robot builder installs on a new robotic creation is a frontal bumper. As to what exactly they plan to do with these last resort sensors is generally vague, there is very little detailed information describing the behaviors to implement in the programming. Most books seem to skim over the subject, indeed other than  eturn right for left impact†and  eturn left for right impact‬ most publications move on to other more enticing subjects such as sonar or mapping. So here I wish to fill in that critical gap in information and discuss in more detail the issues that lie beyond simple  ebumper logic‮

More details later!

Chris

Hi all,

Ever considered making your very own robot test arena? We just finished our up last weekend, and it is essentially a 2 x 4 foot piece of formica covered particle board, with 4 inch high white rails on all the sides. Here, we will be developing the software and hardware in this "robot play area" for our current project.

We have constructed a small universal type robot that we can bolt various sensors to for evaluation. Each sensor will be one level in a behavioral priority arbitration architecture. Then after we have optimised each separate layer independently, Ill design a PCB. This will be a universal Priority Arb. Arch. Board, with sockets for 8 PIC processors that all run in paralell. There will be three or four digital demultiplexers, and of coarse the arbiter PIC, which we allready have from our PAAMI project.

So our PICbot II project will develop the "impact module", which will have six bumper plate inputs and will contain all essential escape routines and some unual ones as well. A single subsume line output goes high when the chip decieds it must take action upon an impact detect.

Other PICbots will be for developing the other modules, such as IR avoid, sonar cruise, beacon homing, charging, docking, and task planning. Ill post a shot I took last night of the arena on my web site.

Chris comets133@yahoo.com

www.schursastrophotography.com/roboticsmain.html

HI all,

If you watch any football this season from ESPN, CBS, or NBC, look carefully at the goalposts - those teleoperated robotic cameras you see that get all the great shots from the vantage point they are at are my babies - I design, maintain and repair those guys for a living. They are operated from thousands of feet away using a link of sending RS232 serial data over a coax cable.

Ive got the basic platform for our new PICBOT II running. A 16F73 PIc processor sends commands serially to two servo PICs, with software I designed to control them. Our next phase is to develop bumper plates out of double sided circuit board material that is dirt cheap, and can be made any size and shape. My real interest is to improve the AI behind bumper navigation and to design the bumper layer of the prioritized arbitration architecture most effectively. Then Ill do a write up detailing the math, action and bumper design for the robotics community to see.

Chris comets133@yahoo.com

Hi all,

were working on a series of small table top robots now, to develop in sections the various levels of subsumption architecture, one level at a time. I am doing this piece meal, to eventually develop a superior home cleaning robot. First, we are tackling the impact level, with bumpers and a new design for a plate style bumper. First I am working on a one chip per servo driver, using a PIC12f629, an under a buck processor to take serial data from the main processor and control a single servo. Ill of corse share it with all of you when we get it perfected, and you can have both the schematic and software ready to burn for your own servo drivers.

Chris

10 Aug 2006 (updated 10 Aug 2006 at 15:19 UTC) »

HI all,

Ok, well were finally finished with the Geobot project, and I would like to present to you the Final Report:

www.schursastrophotography.com/robotics/geobotfinal.html

There can be no doubt that the technologies we have gained much experience in on this project will be a great foundation for future out door robotics projects for us in the comming days.

Chris

comets133@yahoo.com

Hi all,

We have made another significant milestone in the progress of the Geobot, the rock collecting robot. The arm, motorized scoop, and ground detect sensors are done. We connected the interface to the processor tonight, and were able to move the arm smoothly, turn on the motorized rock scoop, and yes even detect the ground with contact switches. Our next step is to actually program the Finite state machine that will do the actual rock aqusition, stow the arm, and return the sample to home! This is certainly the most sophisticated robotic arm we have constructed yet. On my main page, Ive posted a new shot a few minutes ago of the geobot with its scoop arm raised:

http://www.schursastrophotography.com/roboticsmain.html

Note the new "Schurs Artificial intelligence Scale" at the top of the page too...

Chris

comets133@yahoo.com

17 Jul 2006 (updated 17 Jul 2006 at 03:48 UTC) »

Hi all,

Now that we are back from Australia, we are making good progress once again on the Geobot. The motorized power rock scoop is coming together fairly well, and a quick test in the back yard shows that it really does collect small rocks very well. So here is where we are at right now, and a movie of the robot performing its eventual rock collecting mission (without arm yet) in a street test.

www.schursastrophotography.com/robotics/rockscoop1.html

Chris

11 Jul 2006 (updated 11 Jul 2006 at 18:28 UTC) »

Hi all,

Just got back from 2 weeks in Queensland Australia, diggin dinosaurs and doing some astronomy. Time to get back to the Geobot. I finally found a brush to use for my rock scoop. Its a ceramic core, with stiff nylon fibers used for a hair brush. I cut a 2 inch wide section out of it, and am currently mounting the motor to it. This will be lowered by the new arm we installed 2 weeks ago to the ground, and turned on when it touches the ground. A wire mesh cup will catch the spray of material that comes from the brush, including small rocks and pebbles.

So we have the new arm working fine, the robot is turning around at its destination which is 100 feet for now, and returns very nearly to where it started just fine. The brush collection assembly is the last part to put on, but its not so easy to make!

I keep asking myself where Im going to store this huge robot after we accomplish our goal of rock collection...

Write me,

Chris comets133@yahoo.com

Here is a progress report on the Geobot. The devantech compass is finally working, the unit we got simply would not calibrate for blood or money. We rotated it in the cal mode over and over, but the cal done lamp would not change. Finally, in desparation, we calibrated it using the old style previous rev software version method. It worked. Apparently, we got an unmarked chip, which was not the newest version.

Anyway, The robot now goes out a preset distance, rotates 180, and returns very near the start position. We are ready to add the arm now, that will collect the rock samples from the remote location and return with them.

So two problems we encountered this week are first, the tank base I used (Stuart M5) doesnt have the power to rotate in place on 3 inch deep grass. We stick to rocky flats for now. Second, the motors genrate a horrendous magnetic field from the magnets inside them, which cause up to 20 degree offsets at certain angles from the real bearing!

WEll, other than mount the darn compass on a six foot pole, Im going to try to keep missions on the NS - EW line for now, thats where the compass is calibrated to be dead on. Alternately, I can make some sort of look up table for each angle as to what angle really is 180 degrees so It turns around at its destination for the return trip.

The final goal of course will be to send the robot on a rocky gravely plain (common here in Arizona) out to 100 foot distance, collect surface specimens with a motorized scoop with a rotating brush on the end, and return them to the start point.

The project page for the Geobot is at:

http://www.schursastrophotography.com/robotics/geobot_mainpa ge.html

Write me if you have time! chris

comets133@yahoo.com

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