Hexapod Makeover

Hexapod Robots

Re: Hexapod Makeover

Postby surfdabbler » Tue Apr 27, 2010 2:00 pm

I've just caught up on this thread. You've done some great work here, and like everyone else, I'm very jealous of your 3d printer access. :) I was originally thinking of some legs like yours, but I don't have the inspiration or time to make something like that without a 3d printer, so I've just gone for flat perspex cutouts.

It's great reading through and finding that you have come up against many of the same issues that I have been working on. I was originally considering hacking servos with PIC controllers and I2C/SPI, and I may still do that, but I'm way early on in the process compared to you, so I'll be getting it all working with standard servos first.

I was reading your posts on the IK speed. I've just finished optimising my IK code. I'm running an 80MHz PIC32, so performance is pretty critical, but I managed to get the IK code optimised to run at 190Hz, running 20 joints, including walk cycle. Not bad, huh? :) I was pretty happy when I got it to that level. There's also some special methods in there so that it resolves almost perfectly in each iteration, even for large jumps in foot position. This means I only need one iteration per servo-cycle, so I have 70% of the CPU still spare.

I am also planning to do video, but that's a ways off. I don't know if the PIC32 will be fast enough to do the face detection thing. Time will tell.

Keep up the great work. I'll be watching!
surfdabbler
 
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Joined: Thu Jun 18, 2009 12:05 pm

Re: Hexapod Makeover

Postby blegas78 » Tue May 18, 2010 10:15 pm

surfdabbler wrote:I've just caught up on this thread. You've done some great work here, and like everyone else, I'm very jealous of your 3d printer access. :) I was originally thinking of some legs like yours, but I don't have the inspiration or time to make something like that without a 3d printer, so I've just gone for flat perspex cutouts.

It's great reading through and finding that you have come up against many of the same issues that I have been working on. I was originally considering hacking servos with PIC controllers and I2C/SPI, and I may still do that, but I'm way early on in the process compared to you, so I'll be getting it all working with standard servos first.

I was reading your posts on the IK speed. I've just finished optimising my IK code. I'm running an 80MHz PIC32, so performance is pretty critical, but I managed to get the IK code optimised to run at 190Hz, running 20 joints, including walk cycle. Not bad, huh? :) I was pretty happy when I got it to that level. There's also some special methods in there so that it resolves almost perfectly in each iteration, even for large jumps in foot position. This means I only need one iteration per servo-cycle, so I have 70% of the CPU still spare.

I am also planning to do video, but that's a ways off. I don't know if the PIC32 will be fast enough to do the face detection thing. Time will tell.

Keep up the great work. I'll be watching!


Thanks! The 3D printer is nice, but you don't need to be skilled to use it, so I feel like I'm cheating my abilities sometimes when I use it. Well worth it though :)

190Hz is great! Probably what I would expect of a PIC32, I have a few at home which I need to tinker around with. I may look into using the USB on-the-go peripheral.

Vision processing would really be interesting. You can even easily implement cell-phone cameras, like available from Sparkfun. I have one sitting at home that I would like to get connected. These are nice because you don't have to worry about JPEG decompression as like from standard webcams, so it would be much less intensive for processing on a PIC. You could then look at the source code from OpenCV, or start from scratch if you are really hardcore about coding. ;)
blegas78
 
Posts: 110
Joined: Mon Feb 09, 2009 5:34 pm
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