Help : Robotic snake the simpler one

[nayome]

Hey guys i know some people here are pro...can i ask for a help?...we are building a robotic snake using PIC 16f84A...we had the program...the 6-7 servor motors...and etc....the only thing is the body.. .when our snakes move the body won't move as we expected...our snake doesnt have a wheels so it depends upon the power of the servo...Do you have any information on how to build a simpler one...any kind of robotic snakes using 6-7 servo...we really nid this..it's our thesis and now we failed the last semester and need to change our grade if we can build the sidewinding snake that our panelist needs....Thanks....email me...for other information about the robotic snakes [email protected]......

[JesseWelling]

Sidewinding snake you say?
Have you watched any videos of a side winding snake?
Seems like the apropriate place to start.
Off hand I would say 6 servos would be the bare minnium for that kind of movement.
that would probably get you a inverting u type of motion but....
some thing that goes from this 'm' to 'w' would be better becaus it has more contact points (would help with ballance)
but my guess is to have a trulley good sidewinding motion you will need at least 3 points of contact at all times.
and I would make sure the points are not all in a line or else you might as well just go with one point. make a plane
with those three points.
I'll draw a picture.

or just give you this really great video 
http://video.google.com/videoplay?docid=7130994539006744932&q=sidewinder+snake

[Admin]

got pics or video? it will help us understand the problem better.

i think jesse is right, you just dont have enough DOF to perform the proper motions (you need more servos).

[JonHylands]

Have you seen this site:

http://www.snakerobots.com/

It is the obvious place to start.

S2 had ten servos, and each segment had a couple free-rotating wheels on the bottom to allow it to follow an S-motion as it moved, but not slide sideways.

You can click on some of the pictures to get movies, which are quite neat to look at...

- Jon

[Militoy]

In a biological snake, the sidewinding mode of locomotion is used both to optimize movement over soft substrates (like sand), and to minimize contact with the hot ground. To get a good sidewinding motion, the way your snake is jointed will have to force it to “lift” the forward-moving portions as they are pushed forward. Sidewinders I’ve watched typically touch the ground only at 2 zones (the least possible contact). The snake doesn’t need to “tripod” for stability, as the contact zones are curves, not single points. The parts of the snake touching the ground varies in a wave as the snake moves along, so that no single part of the snake stays in contact with the ground for too long at a time.

[JesseWelling]

If you can get that kind of curve out of 6 servos be my guest
People also walk with two contact joints...robots can't do that effectivly yet either.
Although I'll give you that a 'fall' would be negligible in this kind of motion it would
essentialy brake any momentum you had, and would be akin to planing your
foot to change direction.