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Update on MicroRaptor progress

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JonHylands:
In case you guys aren't following, I've made a bunch of blog posts, including several that show progress on a CAD model I have built for the next robot I am building, MicroRaptor.

http://www.huv.com/blog

I expect to start building the robot itself once I get my hands on the Bioloid kit, hopefully sometime in January. In the meantime, I'm cranking away on design work and software.

Interesting book I just finished reading - "On Intelligence" by Jeff Hawkins. An excellent read - I highly recommend it to anyone who likes to think about AI.

- Jon

Admin:
potential problems I see with your CAD . . . hey, im a mechanical engineer its instinctual . . .  :P

http://www.huv.com/blog/uploaded_images/MicroRaptor-02-734314.JPG

the head looks heavy, and the servo that drives the head will not only possibly have torque issues, but also unneccessarily drain lots of power to support the head.

considered using a worm gear instead? or at least some kind of spring force to support the weight?

as for the tail, I am assuming its for balance . . . did your moment arm balancing equations yet?  :P

otherwise the design looks well thought out and stable . . .

JonHylands:
Thanks for the feedback Admin... Being a software guy, I don't always consider everything...

The servos have approximately 200 oz-in of torque, so I don't suspect that will be a big issue.

The leg servos (and specifically the ankles) are going to have a lot more weight on them than the neck servos - I actually wasn't very concerned about the neck.

The tail is to help with balance while walking, yes. I hvaen't done any calculations because (a) I wouldn't have the slightest idea how, and (b) I haven't built the thing yet, nor do I have the kit, so I don't know what all this stuff weighs. I was planning on building and weighing the tail to counteract the weight of the cameras, whatever that ends up being.

Admin:
i guess the experimental way will work . . . but if you want to calculate beforehand . . .

its basically a moment arm balancing equation
http://www.societyofrobots.com/mechanics_statics.shtml#momentbalancing

weight_neck * mass_length_neck = weight_tail * mass_length_tail

where horizontal length is from the pivot point (location of foot on ground, not leg joint) to center of mass of the neck. you just want that equation to balance. ehhh that sounds kinda confusing . . . lemme know if it is . . .

basically it means that if you have a long tail, put the weight at the furthest point possible - results in a lighter tail, yet more effective.

JonHylands:
Yeah, I kind of assumed it was something like that. The two spacers on the tail will be machined from whatever material makes sense to get the weight I need.

Like I said, though, it will have to wait until I actually get the kit...

- Jon

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