MorpHex part 2
Posted on 13 July, 2011
MorpHex, sphere sections mounted on legs
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:
Already drilled and just plugged in the screws for holding it in place when doing the next leg (sorry for the blurry picture):
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 ribs on each side the part gets more rigid, the rib also make sure that the neighbor leg/sphere part doesn’t overlap each other in sphere mode.
Here are some pictures of MorpHex in action with all six sphere parts mounted.
Fully extended body:
Ready for transforming into sphere mode:
Sphere mode! 😀 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.
Still a lot of work left. I’ll start on the upper sphere section when I’m satisfied with the lower section.
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. 🙄
Anyway, pictures tell much more than any words. All parts are handmade, the material is polycarbonate. Here are some pictures of the hinge system:
The hinge-system are going to be placed above the ARC-32 board. Another picture of the hinges in the max/fan position:
This picture illustrate how the sphere sections are going to be mounted to the hinge-system:
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:
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:
I’ll come back with more info on how I’ll attach the servos. Now 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 :
One thing is for sure, my workshop is a complete mess at the moment..
The upper sphere sections are 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..
The camera lens is just for temporary support 😉
The “Nuclear shape”:
I believe having an upper section that can take different shapes might be a cool feature in walking mode.
MorpHex video part II
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:
End of page. Read more about my MorpHex project on page 3.