MorpHex, a sphere formed morphing hexapod

Lynxmotion Legged Robots
101

Hi,

A little setback this evening. It looks like I have to replace all the LM servo horn I used on the 5990’s and use the original instead. There is to much slope between the servo spline and the horn. One solution could be using locktite directly on the spline, but since I already have the original horns I’ll try to use them. They are mm though so I need to use other screws.

I taped together the six sphere parts for the lower leg sections, that’s the only way to get them 100% correctly aligned before mounting them to the legs.

This picture gives a little illustration of how its gonna be.

MorpHex_HalfSphere.jpg
MorpHex_HalfSphere.jpg800×600 238 KB

But first I need to fix the horn issue and calibrate the femurs again… :unamused:

102

I’ve just replaced one of the servo horns and the result was significant much better!

103

Looks great!

104

Thanks Kurt!

All six horns are replaced now. I’ll do the calibration part tomorrow. I just hope my wife doesn’t kill me since I need to use the dinner table when doing the calibration part and she has already complained about the 5990 noise… :laughing:

105

I like it!

Are you referring to the metal servo horns that LM now supplies with sets of six servos? They seem to be different from the ones in the past. I’ve also noticed that they don’t fit very well.

Alan KM6VV

106

Thanks Alan,

I can’t say if they came with a six servo set. But they came in a bag marked HMSH-02. Some of these horns where very loose on the servo spline. The horn that came with the 5990’s was a better fit, I had to press them with force onto the spline.

New update: All femurs are calibrated again. Also need to do some changes to the stand, I might need to use a tube or rod with a smaller diameter so that the feet can come closer when Morphex are on the stand. + some other small adjustments.

107

They tell me the horns are in spec. I will see what I can do to get the tolerances improved.

108

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:

http://zentasrobots.com/wp-content/blogs.dir/3/files/2011/07/MorpHex21.jpg

http://zentasrobots.com/wp-content/blogs.dir/3/files/2011/07/MorpHex22.jpg

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

http://zentasrobots.com/wp-content/blogs.dir/3/files/2011/07/MorpHex23.jpg

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.

http://zentasrobots.com/wp-content/blogs.dir/3/files/2011/07/MorpHex20.jpg

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

Fully extended body:
http://zentasrobots.com/wp-content/blogs.dir/3/files/2011/07/MorpHex25.jpg

Ready for transforming into sphere mode:
http://zentasrobots.com/wp-content/blogs.dir/3/files/2011/07/MorpHex26.jpg

Transforming:
http://zentasrobots.com/wp-content/blogs.dir/3/files/2011/07/MorpHex27.jpg

http://zentasrobots.com/wp-content/blogs.dir/3/files/2011/07/MorpHex28.jpg

Sphere mode! :smiley: 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.
http://zentasrobots.com/wp-content/blogs.dir/3/files/2011/07/MorpHex29.jpg

http://zentasrobots.com/wp-content/blogs.dir/3/files/2011/07/MorpHex30.jpg

Normal body height for walking, the legs have very much free space for moving around without any conflict.
http://zentasrobots.com/wp-content/blogs.dir/3/files/2011/07/MorpHex31.jpg

Still a lot of work left. I’ll start on the upper sphere section when I’m satisfied with the lower section.

EDIT: Did I forgot to tell you that it look pretty cool watching it in action? :wink:

109

Pictures are very good…!
Look amazing

110

Sounds great! Thanks. :smiley:

Thanks DialFonzo, glad you liked it!

111

I am not so good to express myself in english…

But at that point, i think what you do is Art for eyes…!

112

Thanks! :smiley:
Well, its not finished yet though. So far it kinda reminds of a flower opening itself for a new sunny day… :laughing:

113

Nice! I think you mentioned there will be more servos to actuate the upper sphere components. I’m interested to see how it will all come together. :slight_smile:

114

I don’t usually post on here often, but I have to say Zenta, that is absolutely amazing!!!
You’ve definately got an artistic side to your robot building. It’s great to see continued innovation come out of this community :smiley:

If only I had such arty construction skills on my (secret :wink:) project :frowning:.

-1

115

very cool. great work. its good to see that you are solving the issues i had and that you have almost accomplished what you set out to do. it looks great zenta. well done.

you could get this to roll (Potential energy) by kicking the legs out in a sequence pushing the sphere over to its heavier side.
of course this would only work if you had the same weight with in the top section of the sphere to complete a top to bottom roll.

116

Thanks Jim and Zodius!

Glad you liked it Jonny! :smiley:

Well, that’s exactly the way I plan to do it. And I think its the only way to accomplish some sort of rolling motion too.
But the rolling part isn’t my main goal with this project. Its more the transforming part from a ball/sphere to a hexapod. And also letting my kids play with it, where they roll it like a ball and suddenly it transforms into a hexapod. Thats gonna be fun.

They can’t wait to get their own big real Bakugan. :laughing:

117

Yeah, of course. I’ve been thinking about that. I might have to move the battery to the upper section. Maybe use two smaller LiPo’s instead of one big.

118

Yes, I concur. Very impressive!

Maybe call them “ribs”? Should add stiffness at a minimum weight. Don’t know how they all fit into the “compact” posture of the 'bot, but the ribs could be made even wider, and a series of holes used to keep the parts light.

Alan KM6VV

119

Hi Zenta,

I really love the work you’ve done on this! Very innovative and creative! The body (leg) parts really makes it look more massive. Neat that you managed to find white screws which match the design perfectly.

I’m really curious how the last part of the transformation from hex to ball takes place. do you ‘walk’ the legs to a smaller diameter and then slide it in?

I always enjoy your work! Keep inspiring us!

Xan

120

Thanks Alan, Yes ribs sounds like a logic word to use. I do plan to use a slightly thinner material for saving weight, but not higher.

Thanks Xan! :smiley: Glad you liked it.

Yes, I’m using the gait engine when doing the transformation. At that point I only use 2 DOF IK, setting the coxa to a fixed angle. That allow us to also use negative numbers on the IKFeetPosXZ variable so that the feet can move to under the body. When the feet are very close to the center (about 20mm) the legs snap in to the sphere position without any lifting.

To enable the gait I simply set the TravelRequest to “1” (and do a lot of other stuff of course) and then set it to “0” after StepsInGait# cycle counts.

Thanks to your code its pretty easy to modify it. :smiley: