MorpHex, a sphere formed morphing hexapod

Lynxmotion Legged Robots
1

This is a project I’ve been thinking on for a very long time. Shortly explained this is a sphere shaped hexapod that I plan to give the following features:

Roll freely like a ball
Have different sort of locomotion for moving in any direction
Variable inner-body dimensions
Transform from a sphere shape into a hexapod and vice versa
Walk like a hexapod

Before I started to make any exact sketches or started building anything, I shared my ideas with my friend Jeroen Janssen (Xan). We talked about this project when I visited him in Netherlands this summer. At first I was thinking of using a fixed sized inner body with 6 x 4 DOF legs, similar to what I used for the T-Hex hexapod. Another problem was finding a sphere shaped material that I could use. Jeroen and I went to a local toy-shop and I just asked him to look for ball-shaped object. After a little while Jeroen had found a globe! At that moment I got the feeling that using a globe could actually work. After a few months and some searching in different book and toy-shop’s I found a 28cm in diameter globe from Toysrus. It was also cheap and the plastic material seemed to be relative solid (about 3mm thick).

I’m cutting out 12 identical sphere parts. Using a simple handsaw and cutting along the lines of the Longitude every 60 deg. The line of equator was made of 1mm thick dark blue plastic band and was very easy to remove, that resulted in a perfect clean edge too! Here are some pictures of the sphere parts:

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/10/D-Hex00003.jpg

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/10/D-Hex00001.jpg

The map coating was very easy to peel of. The trick was to preheat the surface carefully and then start in one corner and just peel off the whole layer. To the left is the original part. The middle part has the globe/map layer peeled off and the right part is sanded by hand:

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/10/D-Hex00002.jpg

As you can see the material is very transparent, I do have some future ideas of mounting several LED’s for some cool lighting effects.

Morphing inner-body:

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/D-Hex_01.jpg

The principle is very simple. I’m using one digital 5645 servo in the centre of the body, the servo holds two delrin gears.

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex_02.jpg

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/D-Hex_02.jpg

I’m using 7x of the LPA gear sets from Lynxmotion. One gear with SES holes is mounted to each of the 6 outer body sections.

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/D-Hex_03.jpg

This construction makes it possible to adjust the body dimension by about x2 using only one servo.

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/D-Hex_05.jpg

The main reason for making the body like this is to hopefully make some more free space for each leg when the robot are in the walking mode. Even with the increased body size the legs are still going to be highly restricted in free motion caused by the large sphere parts, but I think it will work :wink: I’ve already done some changes to the body section, like replaced the 1,5 mm aluminium parts used on the 6 outer sections to 2mm for more strength and stability. And also some more stuff like an holder for electronics.

There is still a lot of work left and I’m currently working with assembling all the legs. In total there will be 31 servos, 12* 5990 + 19*5645.

I’ll post more info when I’m finished with all the legs and have some more and better photos.

2

Pretty cool!

31 servos :open_mouth: where do the other 6 servos go?

Kurt

3

Looking forward to seeing the changes! This is an awesome build. 8)

4

I may as well give up now… :wink: :laughing:
Very nice. now all is clear on that morphing body part. very nice and inventive. 8)

you have solved a lot of the problems i have faced with this kind of project. the morphing body will help with the distance that each segment has to move.

Im looking forward to this very much. :wink:

from axis to axis (sphere Closed/Open) what is the measurement?
how much does the chassis weigh?

Pure genius zenta.

5

Very elegant design!

We’re all anxious to see it in action. Again, my complements on your excellent design!

Alan KM6VV

6

The small individual panels might be duplicated fairly easily using vacuum forming and a light weight plastic.

7

Thanks Kurt! Now you understand why I wan’t the ARC-32/SSC-32 combo. :wink:
I’ll post some info later of how I’m designing the leg, 4 of them are now complete and 2 more to go.

Thanks Jim! As you know this is old news for you and I’ve not done that much since you got the sneak pictures, but I hope to be able to post more info later.

Thanks Jonny!
Oh no, don’t give up on your project. I would probably do it the similar way you did if I had different goals on the project.
I’m not sure what dimensions you are after but the shortest diameter on the body (coxa-coxa) is 17cm and the largest is 29,4cm. The weight of the body including the SSC +ARC board is 572 gram. I believe this body design could be used for many different leg configurations, ex combined with the 4 DOF T-Hex or ordinary 3 DOF would also be fun.

Thanks Alan!
There is a very long way until you’ll see it in action. Many challenges when it comes to programming, but its going to be fun! :smiley:

True, but the sphere parts need to be very strong and solid, the ordinary thin plastic used for vacuum forming isn’t very strong though.

8

Hi,

Yesterday a local TV company visited me in my workshop and made a short TV program (just a couple of minutes) about me and my robots. Its all in Norwegian so it might not be so very interesting for you but it was very fun though. The program can also be viewed from their website tvvest.no. Look for the tv program “Sendt: 19.11.2010”

EDIT: It starts at 05:32.

The website should look like this:

tvvest19112010.jpg
tvvest19112010.jpg1010×593 75.3 KB

If you try this another day you’ll have to navigate to this exact tv program.

The interview took about 30 minutes but they edited to a very short 3 minutte snip though.

9

I’ve uploaded a new video on YouTube, now with subtitles.

The subs are not perfectly translated, but I tried to do my best.

10

Nice video! But do I need to do somthing to turn on the subtitles?

Kurt

11

You have to watch the video on Youtube, not embedded, and click the [CC] button at the bottom of the video.

Very cool interview! :smiley:

12

Thanks Snailkeeper that did the trick!

Again very cool!!!

Kurt

P.S. - Happy Birthday :smiley:

13

Thanks Kurt and Beth! Glad you liked it. :smiley:

The captions work in embedded to, like Beth said you’ve to turn it on (cc).

14

Very cool video! I wish I had the money (or the free stuff :stuck_out_tongue:) to build things like that. One day I want to build the mech shown in my display picture.

As for the MorpHex project, it reminds me a lot of an old cg animated series I used to watch where one faction had these giant spherelike mechs that could roll and deploy for combat. No idea of what the show was called, but it had planets with thrusters attached.

-1

15

Leg design

To make MorpHex being able to curl up into a ball shape, I’ve decided to go for a little special leg design. Actually, MorpHex is a sort of dual hexapod, where one leg share a common coxa part with two femur and tibia parts.

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex01.jpg

I’m using standard SES brackets, but pay attention to the ASB 15 v2 bracket that holds the two femur servos. The v2 bracket is just perfect for attaching the ASB-04 coxa bracket.

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex02.jpg

5990’s are used for the femur and 5645’s for the tibia and coxa. Notice that the 5990 wires are guided through the 8 mm bearing/SES hole between the ASB-15 v2, LPA lexan spacer and the ASB-04 coxa bracket.

Body modifications

Since my first post about this project I’ve replaced the outer body parts from 1,5 mm to 2 mm thick aluminium, mainly for increased strength and stability (less flexing):

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex04.jpg

Making sure that every gear is aligned correctly was the hardest part when assembling the body section. I solved it by carefully placing one gear at the time and mark the 4 SES holes on each outer bodysection, remove the section, drill the holes and mount the section onto the inner body section again. Repeated this process for all the 6 sections.

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex05.jpg

Instead of using 3mm steel hex screws for holding the 12 ball-bearings onto the inner body I’m using 3mm threaded rods. The rods make it much easier for mounting a holder for battery and electronics.

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex06.jpg

All the six legs are finally assembled, next step is to mount them to the body:

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex08.jpg

MorpHex, taking form

I know it looks kinda messy right now, but I do have plan, :laughing: . This picture show all legs mounted to the body and the upper part have their legs curled up into the ball shape position.

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex12.jpg

Another picture illustrate MorpHex in the walk mode position:

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex14.jpg

I’ve fixed some sphere parts with velcro just for giving you a little hint of how MorpHex are going to look like with all the sphere parts mounted:

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex15.jpg

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex16.jpg

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex17.jpg

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex18.jpg

I might have to modify the feet a little bit (using smaller end caps and modify the ends of the tubes) so that they can be aligned even closer in the curled position. But these pictures illustrate how it’s going to look like at the end:

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex20.jpg

Just for visualization:

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex21.jpg

This is one of my favorite pictures, it kinda remind me of the unfinished Death Star from Star Wars, 8) :

http://zentasrobots.com/wp-content/blogs.dir/3/files/2010/11/MorpHex24.jpg

16

:open_mouth: Whoa!!! :open_mouth:

17

Oooh. that is sweet. well done zenta. that duel hex is a great idea.
[size=150]Truly Awesome! [/size] 8)

18

That is amazing!!!

So far I am counting 31 servos. You might even be able to make it roll…

Kurt

19

Thanks guys! Your comments are highly appreciated!

Thats one of mine goal to achieve. :wink:

There are still a lot of work left (both mechanics and code) and I’m very excited to see if it will work as I hope.

20

I can’t do anything other than be really excited to see it in action…
It’s amazing…

Well done

Eric Nantel