Preprint:

    Samuel R. Buss and Jin-Su Kim.
    "Selectively Damped Least Squares for Inverse Kinematics."
    In Journal of Graphics Tools, vol. 10, no. 3 (2005) 37-49.

    Download submitted journal article version: postscript or PDF. 

Preprint:

    Samuel R. Buss.
    "Introduction to Inverse Kinematics with Jacobian Transpose, Pseudoinverse and Damped Least Squares methods."
    Unpublished survey.

    Download unpublished article: postscript or PDF. 

Movies   

Movies showing the double-Y shape are available in two formats.  Only one update is performed in each time step, so the end effectors do not exactly track the target positions.   (File sizes are 1.7MB to 3.0MB.)

  1. Selectively Damped Least Square (SDLS).   Quicktime(.mov) or AVI format.   This is the new method introduced in the paper.
  2. Damped Least Squares (DLS).    Quicktime(.mov) or AVI format.   A traditional method from robotics.
  3. Pseudoinverse method.    Quicktime(.mov) or AVI format.   An ill-conditioned method.  Includes clamps on the joint angle changes.  Oscillates badly and converges very poorly.
  4. Jacobian transpose method.     Quicktime(.mov) or AVI format.   As illustrated in the movie, it does not work well with multiple end effectors.  It freezes up and oscillates.

Software   

The source code is available in two formats:  PC format in .zip file and Unix format in a gzipped tar file.  You will need to have OpenGL, GLUT and GLUI header files and libraries to compile and run these.  The programs run very fast on my home machine in Visual C++.NET and very slow on my office computer with Visual C++.6.0 (don't ask me why!), so your mileage may vary.  Bug reports appreciated, but the software is not being supported.

Back to Sam Buss's publications page.