Mathematical Model

[saba_rish91]

Hey,

I'm building a quadruped robot. I need to find its mathematical model. How do I start?
I did try to find few papers on that. But, it didn't help me.
Please help.


Thanks in advance.

[Gertlex]

There's various aspects... You weren't clear on what you need.

Here's a forum thread where forces on the servos are discussed.
http://forums.trossenrobotics.com/showthread.php?5349-4-DOF-leg-mechanics-and-torque-requirements

As for the actual walking gaits, there are a few different ones.  The NUKE code implements and documents them.
http://code.google.com/p/arbotix/wiki/NukeTuning#Gaits_Included

Finally, there are a couple of .gif animations in this thread's first post, which demonstrate the movement being done.  On a single leg, it's purely a geometry problem.  Then with four legs, you just have to figure out how to offset the four legs' movements to get actual walking.
http://forums.trossenrobotics.com/showthread.php?4929-My-4DoF-Quad-Mech-Numa

[saba_rish91]

In the thesis (link below)

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.12.2818&rep=rep1&type=pdf

Page 41, in equation 3.6, the vector rBH is constant and hence the derivative must be zero. But, in the next equation (3.7), he has multiplied it with the rotation matrix. I don't understand how he arrived at this.

Please help.