MorpHex, a sphere formed morphing hexapod

Hexapod Robots

Re: MorpHex, a sphere formed morphing hexapod

Postby Zenta » Sat Jul 09, 2011 9:01 am

TemplarGFX wrote:If the Sphere parts are attached to the Femur sections rather than the Tibia sections you could use angle changes on the Tibia servers to shift the centre of gravity to make it roll in any direction you like. Put the Tibias flush with the sphere at the point on the sphere you want it to roll towards, and the Tibias on the opposite side point in towards the centre of the sphere. it should be enough of a shifting in weight to cause it roll providing your Sphere sections are solid.

I'am afraid just moving the tibias isn't enough to change the gravity. I'm not sure how to attach the sphere parts to the femur section without getting in conflict with free movement of the legs. Also I'm not using 31 servos, but 25. So there are legs only on the bottom part of the sphere.

Yesterday evening I temporarily mounted three of the sphere sections using strong velcro. I did it just for testing. So far it seem to work very well! :D MorpHex curled together like a sphere and back to a hexapod. With the body fully expanded the legs got very much freedom even with the sphere parts mounted. Tomorrow I'll temporarily mount the other three (have to sand them first).

After that I'll reinforce the sphere sections, probably using expanded PVC. And permanently mount them to the tibia sections. The next step after that is the upper sphere section.
Zenta
 
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Re: MorpHex, a sphere formed morphing hexapod

Postby TemplarGFX » Sat Jul 09, 2011 10:26 am

I cant wait to see it actually unfold!
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Re: MorpHex, a sphere formed morphing hexapod

Postby Zenta » Tue Jul 12, 2011 8:18 pm

Hi,

A new update about my MorpHex project. I didn't have time to take some good quality pictures because I'm working with some gardening and renovating stuff that occupies my "photo studio". Some workshop pics with bad lighting was my only option last evening/night.

Anyway, I've been very eager to get the lower sphere sections mounted onto the legs. So eager that I selected a rather easy way by using some counter sink white nylon screws. I'm planning to use three screws on each sphere part and mount it to the ASB-04 tibia bracket. So far I'm using only two for testing. It was a bit tricky to align the hole for drilling, so I used a LED as a lamp behind the sphere part:

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Already drilled and just plugged in the screws for holding it in place when doing the next leg (sorry for the blurry picture):

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Btw, I'm also planning to reinforce each sphere part. I did just a simple test, the final result will be better. The plastic material is Poly Carbonate. By mounting a rail (or what should we call it?) on each side the part gets more rigid, the rail also make sure that the neighbor leg/sphere part doesn't overlap each other in sphere mode.

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Here are some pictures of MorpHex in action with all six sphere parts mounted.

Fully extended body:
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Ready for transforming into sphere mode:
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Transforming:
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Sphere mode! :D As you can see there are some small adjustments to do, and I've already done some improvements today to get them even better aligned. but so far, so good.
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Normal body height for walking, the legs have very much free space for moving around without any conflict.
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Still a lot of work left. I'll start on the upper sphere section when I'm satisfied with the lower section.
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Re: MorpHex, a sphere formed morphing hexapod

Postby TemplarGFX » Tue Jul 12, 2011 9:08 pm

that is awesome!
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Re: MorpHex, a sphere formed morphing hexapod

Postby Zenta » Tue Sep 13, 2011 12:22 pm

Hi,

Its been a while since I last got some time for working on this project. But luckily I've had some time now and then for working on the upper sphere sections. I mentioned earlier that I'm using only six servos for controlling the six upper sphere sections. This mean that each sphere section only have 1 DOF of movement. If each sphere section where coupled together with a simple joint/hinge at the top center of the upper sphere half they wouldn't be able to move at all or at least not at the same time. That's because of several mechanical obstructions between the sphere sections. So I had to figure out a mechanical hinge solution that made the sphere section translate a little away from the top center before it could swing out and upward (bad english.. sight). I hope you get what I mean. :roll:

Anyway, pictures tell much more that any words. All parts are handmade, the material is polycarbonate. Here are some pictures of the hinge system:

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The hinge-system are going to be placed above the ARC-32 board. Another picture of the hinges in the max/fan position:

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This picture illustrate how the sphere sections are going to be mounted to the hinge-system:

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Just for the fun of it I've placed the upper sections loosely on top of MorpHex just for giving you an image of how it will be at the end:

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As you can see, the sphere parts does deflect a little under load, but hopefully its not going to be a problem. I'll probably need to make sure there is a little gap between the upper and lower sphere sections:

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I'll come back with more info on how I'll attach the servos. At the moment I'm also very curious to see how it will perform when the upper sections are mounted. It will add about 1,2 kg extra load. Earlier I did some testings and it seemed to perform ok with the extra load. The extra load was 3 beefy 3S LiPo's :lol: :

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One thing is for sure, my workshop is a complete mess at the moment.. :roll:

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New update

Postby Zenta » Sun Sep 18, 2011 8:34 pm

Hi,

The upper sphere sections are now mounted onto the hinge/linkage system.

So today I took some more pictures with a darker background for better contrast, do I need to say more.. :wink:

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I believe having an upper section that can take different shapes might be a cool feature in walking mode.

-Zenta
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MorpHex video part II

Postby Zenta » Sat Dec 10, 2011 10:47 am

Hi,

Sadly I've not had much time for robotics this year. But yesterday I finally got some time for shooting a video of MorpHex. I'm still not finished so there are still some features missing, like rolling. Hopefully there will be a part III video too. I'll post more details later with some pictures.
In the meantime I hope you'll enjoy this video:




-Zenta
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Re: MorpHex, a sphere formed morphing hexapod

Postby Mark » Sat Dec 10, 2011 4:11 pm

That is Awesome.

Great work.
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