On Mon, 2011-05-23 at 11:37 -0400, Kent A. Reed wrote: > On 5/23/2011 9:17 AM, Javier Ros wrote: > > Viesturs, > > > > Just in case, and without trying to dig deep into the problem: > > > > Euler angles can be singular at certain positions. That is they are unable > > to > > give a rotation or base change matrix when at such positions. > > > > If you experience estrange problems only when the angles are close to 0 or > > to 90 degrees it is possible that our problem is related to this. > > > > <...> > > > > Hope this helps, > > > > Javier > > > Viesturs et al.: > > Javier is quite correct. If you want go to searching for explanations, > The situation is called "gimbal lock" and the USA could have lost the > Lunar Lander on the Apollo 11 mission because of it > (http://en.wikipedia.org/wiki/Gimbal_lock). It's bad enough when your > wrist flips over. It's got to be a lot scarier when your spacecraft > controls lock up! > > I meant to bring it up yesterday when I saw your description but instead > I went to watch my grandson play soccer/football. Sorry, but grandkids > come first:-)
Oh, Duh! Traveled across state this weekend to watch my oldest granddaughter as "Alice" in a Jr. High production of Alice in Wonderland. > > As an aside, I have no experience---practical or theoretical---with > robot arms but I'm interested in your problem because I want my grandson > and I to build a robot arm as part of a chess-playing machine. It will > be more along the lines of a LynxMotion arm in size and robustness, but > I still have to understand the kinematics. > > I used your list of serial-kinematics requirements (email message > 2011/1/4) as an exercise to learn how to use Creo Elements Personal > Edition from PTC. If I set up my account correctly, you can see my first > crude attempt at > http://www.mediafire.com/file/q10zd56hbc8ytdb/ViestursRobot-annotated.pdf > > As you can see, I took liberties in naming the components:-) > > Regards, > Kent > > > > ------------------------------------------------------------------------------ > What Every C/C++ and Fortran developer Should Know! > Read this article and learn how Intel has extended the reach of its > next-generation tools to help Windows* and Linux* C/C++ and Fortran > developers boost performance applications - including clusters. > http://p.sf.net/sfu/intel-dev2devmay > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ What Every C/C++ and Fortran developer Should Know! Read this article and learn how Intel has extended the reach of its next-generation tools to help Windows* and Linux* C/C++ and Fortran developers boost performance applications - including clusters. http://p.sf.net/sfu/intel-dev2devmay _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
