Re: Reaction-force space / Spatial algebra

On Tue, 6 Apr 2004, Joshua Hale wrote:

[...]
> I've been reading "Robot Dynamics Algorithms" -what a great book- and am
> having a problem with the reaction-force space. This is represented by a
> matrix orthogonal to the joint-space matrix and is denoted R in
> Featherstone's book. Anyhow, you need to calculate "velocity-product"
> terms Ra + R'v as part of a kinematic loop resolution algorithm... this
> is a step that confuses me because I'm not sure how to calculate R' (the
> derivative of R). Its straightforward apparently, and includes the term
> v X R... if you have a copy of the book I'm looking at page 164.
I understand what you are talking about.

> So if spatial algebra and joint reaction-force are concepts under your
> command please give me a shout and I'll explain myself in more detail if
> necessary!
This is strange usage of a mailinglist :-) Don't be afraid to ask your
question right away. Anyway, I don't really understand what your
question is... You want to understand where the formula for the
derivative of R comes from? You could take a look at page 59 of
 <http://people.mech.kuleuven.ac.be/~bruyninc/robotics.ps.gz>

Herman

-- 
  K.U.Leuven, Mechanical Engineering, Robotics Research Group
<http://people.mech.kuleuven.ac.be/~bruyninc> Tel: +32 16 322480