I currently have a description of my 22 joint robot in "classic" DH parameters. However, I would like the "modified" parameters. Is this conversion as simple as shifting the $a$ and $alpha$ columns of the parameter table by one row?

As you can imagine, 22 joints is a lot, so I'd rather not re-derive all the parameters if I don't have to. (Actually, the classic parameters are pulled out of OpenRave with the command: planningutils.GetDHParameters(robot).


1 Answer 1


Unfortunately it is not as simple as just shifting the a and alpha columns, as the locations of the frames and the directions of their axes can also change when moving from one DH formulation to another.

As you can see in the Wikipedia entry on Modified DH Parameters, these key differences result in a number of changes to how the overall transformation matrix is built.


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