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Topic: My Hexapod walks! (Read 4711 times) previous topic - next topic

vinceherman

http://www.vinceherman.net/robot/media/IMG_0071.MOV

Yes, I am just starting to get it together.
Yes, wires everywhere.
But IT'S ALIVE!!!!

Next steps include
  • smoothing the foot lift and set, rather than the slam up and down I have now.
  • Remote Control input
  • Solve the logic for transitions from one walking mode to another


Then, further down the road, video processing for navigation and object recognition.

But small steps as they say.


cr0sh

Is that a custom bracket job, or did you purchase it from somewhere? It looks great, nonetheless! I've always wanted to try and replicate the ODEX-1 full-scale using modern materials, motor drives, electronics and computational advances - but aside from the cost (which might be fairly large), I just don't have the time with all my other projects waiting in line!

:)
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

mowcius

Looks great

Any way you could speed it up to chase people?  ;D

Mowcius

Ocon

I'm making hexapod too for my kid.
Could you share the code?

Thanks.
http://www.pinotronics.com

vinceherman

Quote
Is that a custom bracket job, or did you purchase it from somewhere?

http://www.lynxmotion.com/

Our first work was with wooden brackets, because we could manufacture then with the band saw and a drill.  They simply bolted to the servo horns.  But this puts all of the side load on the output shaft of the servo.  The commercial brackets mount the servo in a frame that has a bearing on the bottom.  The bracket engages both the servo horn on one side and the bearing on the other, making the joint much stronger.  The down side is cost.

Quote
Any way you could speed it up to chase people?

Certainly it can walk faster.  The entire step cycle is 4 seconds.  I think that the step cycle can be reduced down to a half second or so.  That would be 8 times faster.  We will do testing to see how fast it can go without loosing accuracy on the step smoothness.

Quote
Could you share the code?

Absolutely.  I have to clean up the code a bit, and put in some explanation for what the various elements are there for.  I did modify the servo library to handle servo reversing and servo trim.  I will include those files.  They are from the 0017 version of the IDE.  I have not tested them with 0018.  The servo library did change some, and I have not merged my changes into the 0018 version of the library yet.

What components are you using?  I got the Phoenix chassis, somewhat ant like.  There are also radial chassis.  My code is written for the ant version, but would work with the radial model with the legs pointed out sideways like a crab.

So far, we only walk forward.  But we have constructed the various functions with hooks to hang future functionality on, like RC direction and speed control, rotational movement, translational movement (mix of forward and sideways movement with the orientation remaining the same), and turning.

Federico

Looks like you are using the phoenix body and the "round hexapod" legs, am I right? I am interested in creating a phoenix arduino controlled robot... What type of motors are they? If I remember well another of your posts you use the Mega, right?
I will follow your project with interest and Ihope to contribute!
Federico
Federico - Sideralis
Arduino &C: http://www.sideralis.org
Foto: http://blackman.amicofigo.com

Ferret

Hi vince,

If your looking to keep the RC side of your hexapod project all Arduino you might be interested in some of the code I have posted while looking for assistance with a very nood question.
http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1267236058

I'm currently using a Duemilanove with Liquidware Input sheilds as a dual stick 6 button transmitter via xbee for a RC tank project.

Have you implemented any IK into the movements?

Federico

I have read many times about this invers kinematic. What is exactly? :)
Federico - Sideralis
Arduino &C: http://www.sideralis.org
Foto: http://blackman.amicofigo.com

vinceherman

http://en.wikipedia.org/wiki/Inverse_kinematics

It probably encompasses much more than what I am doing, but I still use the term to describe it.

Basically, if I know that I want the foot of one leg to be in a certain position, I can use algebra and trigonometric functions to calculate the angles of each joint that will put the foot in that position.

If I get a chance, I will write up a description of the formulas I am using.

It was a lot of fun using my dormant math skillz   ;D

Osgeld

ack quicktime ... must reboot

but sounds quite cool
http://arduino.cc/forum/index.php?action=unread;boards=2,3,4,5,67,6,7,8,9,10,11,66,12,13,15,14,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,86,87,89,1;ALL

the1evilgenius

Looks awesome. I'm working on the radial hexapod body from lynxmotion.

I've been reading alot on the internet (probably too much for my own good because I have too many ideas floating around in my head), but I digress.

The Mega looks like the best solution for the robot for starters at least. How did you modify it to control the extra servos? I can't find any details on that aspect of using the Mega to control 18 servos.

mem

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How did you modify it to control the extra servos?

You don't need to modify anything to control 18 servos with the mega, the mega supports up to 48 servos with the standard Servo library.

The changes vinceherman made were to provide configuration to reverse the servo direction and to trim the position of the servo.

the1evilgenius

Noted.

Thanks for the prompt response, mem. I thought that was the case; I just misunderstood other posts I had read.

Federico

I am wondering if there any reason for not including this sort of modification in the standard servo library?
Federico - Sideralis
Arduino &C: http://www.sideralis.org
Foto: http://blackman.amicofigo.com

sciguy

Why would you need the modification?  To lesen the maximum amount of servos?
I don't understand what you mean.
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