Praying Mantis Robot Project!

Hi everyone! I’ve finished cutting out about 98% of the parts for the robot’s torso and I’m going to start testing one of the arms now so I should hopefully be able to get a video of it working soon - while then, you’ll have to settle for a photo. :mrgreen:

Here’s the video - the movements are a bit jerky at the moment but I was just testing if everything works (i.e. the servos don’t fail under the load) so I’ll upload a video with smoother movement later on or maybe tomorrow. Enjoy! :mrgreen:

Hi again everyone! I’ve gotten some better movement with the arms and I think it looks like some kind of dancing move but I’ll let you guys decide that. :mrgreen:

Here’s a video - ENJOY! :smiley:

I take it that’s a leg? You’ll probably need some kind of rubber “boot” to get traction on the floor.

How well does it handle a load? What servos did you use again?

Nice!

Alan KM6VV

Thanks for the comment! :mrgreen:

It’s technically an arm but as the video (which innerbreed posted) on the first page shows, the Praying Mantis uses it’s arms as well as it’s legs to walk (which I never realised before :blush:). Most of the load will be taken by the four normal legs so the arms will be used for basic walking when using a hexapod walking gait but I haven’t tested the load handling yet - I’ll do that later on or maybe tomorrow. I was thinking of making some customized rubber boots for the ends but they’ll be done later once I’ve got the basic structure ready.

The servos I’m using at the moment for the arms are HS-422’s but I’ll probably upgrade them once I’ve carried out a few more tests with the other arm (i.e. picking up objects, etc.). :smiley:

422’s. yeah, rather limiting. Might get by for arms, but I suspect you’ll want '645MGs all around (depending on leg segment lengths, of course).

The digital servos are really nice, I’m playing with a couple, but expensive for a hexapod!

Alan KM6VV

Yeah I was going for the 645’s for the legs anyway - they shorter than my spider robot’s (about 9 cm between servo horn centres diagonally) but they are going to have to support some more weight now (the addition of the torso). It’s going to be costly! :unamused:

The digital servos are awesome! :mrgreen:

Hi everyone! I’ve been busy again but I’ve managed to get the top half of the mantis robot completed (more or less - I’m still missing a head which I’ll make on Monday/Tuesday). :mrgreen:

I’ve got some time over the weekend so I’ll work on the programming then. Here’s a photo :smiley::

Quite colorful!

You’ve done some great work here.

Alan KM6VV

Thanks! :mrgreen:

Turns out that 2 of my 8 HS-422’s don’t work for some reason so I’ve ordered some more (HS-645 this time) as well as 645’s for the legs. I’ll be cutting out the body for the robot tomorrow so I’ll upload some photos of that when they’re done. :mrgreen:

I was thinking of adding a servo that could rotate the torso in the horizontal plane - would this be possible? I don’t want to apply too much force on the servo doing the rotations.

Thanks! :mrgreen:

P.S. I received my 645’s today so I’ll commence the building of the bottom half tomorrow. :smiley:

I cut out the body plates for the robot today - what do you guys think? :mrgreen:

Once again, excellent work!

That’s a lotta little holes around the servo hub patterns!

Alan KM6VV

i good idea as far as i can see.

i second Alans comment. great work. 8)

Thanks for all the great comments! :mrgreen:

I was planning on positioning the back two legs at 45 degrees so I decided to add the extra holes - but then adding them only for the back legs would look weird so I decided to repeat it for all the legs. :smiley:

I’m going to start putting it all together tonight and tomorrow so hopefully I’ll have some more photos by then. 8)

Well the screws took longer to find than I expected but then I was expecting it - nothing ever follows my schedules. :unamused:
Anyway, I’ve started to assemble the base of the robot and I’m going to program it to walk without the torso for the time being so I can get rid of any problems with the base servo alignments (I want them to be symmetrical otherwise I’ll get the same biased walking problem as I had with NEXUS).

Here’s a photo of the base so far! :mrgreen:

Looks like it’s coming together!

I don’t think I see a “spacer” hole pattern. Will you add spacers to support the two chassis panels?
Also curious how you will mount the electronics, battery and power switch(es)?

Looks good!

Alan KM6VV

The electronics will be mounted on the base plate of the bottom half of the Mantis’ body and the power switch (I’ll a using a toggle) will poke through a hole on the top plate. The battery pack will slide under the PCB this time instead of being mounted on the top - it’ll look much better out of sight. :mrgreen:

Hope this answered your questions. :smiley:


So, what holds the two plates together? Just curious.

Nice PCB!

Alan KM6VV