A-pod, an ant inspired hexapod

Hexapod Robots

Re: A-pod, an ant inspired hexapod

Postby Zenta » Mon Jul 20, 2009 6:51 am

Hi,
HansWerner wrote:Because you are improving the movement of the legs and you are stated that the legs of the A-pod are shorter compared to real ants:
Do you think that will be a problem and will slow the movement (walking) of the A-pod down ?

I'm not sure if I understand your Q exactly. But the main problem for A-pod when walking was the flexibilty of each leg combined with a relative high weigth and how the mass are distributed. The relative large and heavy head and abdomen makes A-pod more unstable than just having a small body with the all the mass more centered.

Making the legs longer would require much stronger servos.

HansWerner wrote:Have you studied the walk of real ants maybe in slow motion ?

Yes, I've tried watching them live (and other insects too). They mostly uses the fastest gait (tripod) when running.

HansWerner wrote:I hope you don`t change your mind and start with a new project.
I like the main concept of an ant like robot.
I would like to see climbing the A-pod above obstacles and maybe autonomous collecting can`s.

I wont start a new project yet ;) And I'll work more on the A-pod. Actually, I'm just finished doing some mechanical reinforcements to the legs. I just have to recalibrate them. I'll post more info later (soon going for a summer vacation).

-Zenta
Zenta
 
Posts: 92
Joined: Fri Sep 26, 2008 5:23 pm

Re: A-pod, an ant inspired hexapod

Postby HansWerner » Mon Jul 20, 2009 7:45 pm

"The relative large and heavy head and abdomen makes A-pod more unstable than just having a small body with the all the mass more centered."

What is the main problem with the distribution of the mass ?
Why can't it not be centered ?
Is there not enough space in the middle of the body ?

"The relative large and heavy head and abdomen ..."

Is there a change to make the head and/or abdomen lighter ?

"Making the legs longer would require much stronger servos."

How strong would this influence the weight of the A-pod and enery consumption of the battery ?
Which materials would you chose if you had enough money ?
What would be the best compromise between size, walking speed, weight, battery consumption by disregarding costs ?

IMHO, I think the weight should be below 5 Kg to carry the robot easily around.

Sorry for my bad english.
HansWerner
 
Posts: 2
Joined: Sat Jul 18, 2009 5:22 pm

Update, some modifications and new pictures.

Postby Zenta » Tue Sep 15, 2009 7:00 am

Hi,

I thought it was time for a little update about A-Pod. As mentioned before, I've done some minor reinforcements to the legs and rebuilt the abdomen joint. The abdomen 2 DOF joint uses 2x 645MG.

Here are two pictures showing the legs with double femur parts and a bracket for stabilizing the femur servo. This made the legs much more stable.

Image

Image

Two pictures of the new abdomen joint. I'm using the molded injection hinge from LM and a custom plastic bracket for mounting the two servos together.

Image

Image

And here are some new pictures of A-Pod:

Image

Image

Image

Image

Image

I've not done anything with the code yet. I wont post any new vids before I'm satisfied with the walking part. It walks much better now but the code need some changes I'll post more about that later. I'm still working with some outdoor projects and therefore I've had very little time for robotics. Hopefully later this autumn.

-Zenta
Zenta
 
Posts: 92
Joined: Fri Sep 26, 2008 5:23 pm

Re: A-pod, an ant inspired hexapod

Postby blegas78 » Tue Sep 15, 2009 3:15 pm

I saw the way the first femur servos were mounted and immediately thought they needed something a little more for stability, as my first attempt at making a hexapod six years ago had a similar design, and the servo tabs eventually broke off on a couple of servos. :?

I look forward to seeing it walk, this is certainly one of the few hexapods out there that really leaves an impression in peoples minds!
blegas78
 
Posts: 110
Joined: Mon Feb 09, 2009 5:34 pm
Location: Tucson, Arizona

Re: A-pod, an ant inspired hexapod

Postby Aggrav8d » Sat Apr 10, 2010 4:55 pm

I see on the "far" side of each servo you have a bracket that supports the second brace. It looks like it is self-clamping and self-glued. Did that come with the 645? Did you make it yourself? It would be perfect for my hexapod.

and a custom plastic bracket for mounting the two servos together.


Ah, right. Nevermind :)
Aggrav8d
 
Posts: 52
Joined: Mon Apr 05, 2010 7:38 pm

Re: A-pod, an ant inspired hexapod

Postby Zenta » Sun Apr 11, 2010 6:47 am

Aggrav8d wrote:I see on the "far" side of each servo you have a bracket that supports the second brace. It looks like it is self-clamping and self-glued. Did that come with the 645? Did you make it yourself? It would be perfect for my hexapod.

If you are thinking of the servo hinges I used on the femur and tibia servos, you'll find them here: http://www.lynxmotion.com/Product.aspx?productID=399&CategoryID=87.

-Zenta
Zenta
 
Posts: 92
Joined: Fri Sep 26, 2008 5:23 pm

Re: A-pod, an ant inspired hexapod

Postby Aggrav8d » Tue Apr 13, 2010 3:50 pm

Those are exactly the ones. $6 each?! They're $0.20 parts! There's got to be a cheaper source for vacuum molded parts.
Aggrav8d
 
Posts: 52
Joined: Mon Apr 05, 2010 7:38 pm

Re: A-pod, an ant inspired hexapod

Postby innerbreed » Tue Apr 13, 2010 8:27 pm

Lynxmotion are the Sole manufacture of this part. they hold the copyright to it as well.
not sure were you are based but you can use there uk Distributor if here?
http://www.active-robots.com/products/m ... ware.shtml

how many do you need? i have a few laying about.... and not as expensive!
innerbreed
 
Posts: 154
Joined: Mon Jun 29, 2009 4:43 pm
Location: Cambridge UK

Re: A-pod, an ant inspired hexapod

Postby Aggrav8d » Tue Apr 13, 2010 10:05 pm

I'm in Vancouver, Canada - about 10 time zones away from you.

I'd want to get 12 of the clamps and associated ball bearings which will probably cost $80. Ridiculous.

I'm working with TowerPro servos at the moment. If I knew of a servo that included an different back plate (you know, with the ball-bearing attachment built-in) I'd switch in a heartbeat.

I wish some enterprising young soul would up and design a better servo.
Aggrav8d
 
Posts: 52
Joined: Mon Apr 05, 2010 7:38 pm

Re: A-pod, an ant inspired hexapod

Postby innerbreed » Wed Apr 14, 2010 9:52 am

Thanks for the PM. No worrys mate. One thing i did try last year with hitec servos was to remove the back casing from the servo, drill a hole though it, then push a screw though it and attach the ball baring directly to the servo back. Then just replace the casing.
innerbreed
 
Posts: 154
Joined: Mon Jun 29, 2009 4:43 pm
Location: Cambridge UK

PreviousNext

Return to Hexapods

Who is online

Users browsing this forum: Bing [Bot] and 2 guests