Spider Envy
Posted April 3, 2008 by Ash
3 Comments »
Wow look at the motion control on this one. 
I posted about Matt Denton’s awesome spider bot before on AusRobotics. This time he has taught it to draw. I just cant’t get over how nicely he has a) designed and machined it and b) programmed it to move.
The motion (especially at the end when it zooms out a bit) is exactly how you imagine it will look when these things start coming over the hills with their lasers firing 
I definitely feel that we are entering an age where more and more people will be fusing artistry with the normal functionality of robotics development. It won’t be enough to get it to walk. It will also have to have "personality".
This may not indicate such great precision as it first appears.
The pen is under control of the “average” of the 6 legs, and therefore will be subject to a 1/sqrt(6) “sample variance” factor.
So if each leg is good to 1 mm accuracy (probably pretty gross obver-estimate, but let’s take for illustration purposes) the overall positioning of the pen will be 1/sqrt(6) == .4 mm accuracy.
Since the leg positions are not statistically independent, there may be an even larger correction factor using some “non random” techniques — e.g. using small variations in position for certain legs that are properly phased.
I’ve tried a similar approach in the “Ninjabot” to try to improve dynamic balancing. (With mixed success.
I was more talking about the walking gait actually. It seems as if it has been specifically programmed to more accurately match a real spider rather than the simple hexapod/octopod gaits i have seen elsewhere.
Of course that might be because mose of the hex/octopods i have seen have been symmetrical around the vertical axis and so didn’t require the same motions to move and position themselves.
Would be interesting to see the software behind it though!
I saw a vid of a dynamically balancing humanoid that you might be interested in. I was wondering if you could scale down the technique to work on something as small as the little humanoid you are working on. I’ll post it as soon as I find it again.
Ahh. I just looked up Matt Denton’s site listed in the vid and found that his company actually specialises in animatronics.
Check out this link to some videos of their other hexapods. The 3rd one of the tortoise is great!
http://www.micromagicsystems.com/#/hexapodv4/4516342130