Mr. What's Klann Walking Linkage
$URL: svn+ssh:// $
$Id: Klann.html 280 2013-10-22 20:04:09Z mrwhat $

Mr. What's Klann Walking Linkage

Another popular walking linkage is the Klann linkage.

A Klann linkage was described in a manner similar to the method used to characterize the Jansen linkage above, and animated. The dimensions recovered from the patent seem to be sub-optimal in several ways. The measurements have many round numbers and are very symetric, as if designed by a human, and not (yet) optimized by a computer.

I wrote an optimizer for the Klann linkage, and got an optimized Klann geometry, with these dimensions :

   AC=17.5; Bx=-38.8; By=-12.5; Dx=-14.6; Dy=41.9; BH=23.7; CF=73.4; CH=38.8; DE=34.1; EF=57.7; EG=111.7; FG=59; FH=35.2;
and this optimized Klann orbit.

I worry that this linkage is just not as smooth (torque ripple) as Jansen. It looks to me like we are at some extreme geometry at some parts of the orbit, where the ground forces on a moving mass will not do much to help keep the crank rotating. (Nearly parallel forces, little vector in the direction helping crank rotation)

Building parts (Klann)

Some simple (non-braced) parts have been drawn for 3D printing. The complete (non-braced) assembly has 7 unique parts. The leg and rocker-bar can be re-used on each side by flipping them over. You can type make klann to generate these parts from openscad.

For each half-assembly (one leg pair, sharing a crank), print:

  1. (1 ea) main, crankArm, pulley
  2. (2 ea) DE, BH, leg, rocker
Glue two pulley halves together to make a full pulley for the central crankshaft at A. The two "main" parts can be glued together around the main crankshaft and pulley for the main central brace. Large axles can be used at B and D as a primary structure to hold the payload, and connect two quad-leg assemblies together for a walker. An additional brace/frame can be attached below the B pivots, or along the top of the main assembly.
Last modified: 130910