Birds and Four Bar Linkages

Fri, 13 May 2011

All sorts of family related chores to do today but I have managed to squeeze in a bit of work on the bird project. I was trying to change the way the head moves to give it a little twist as it moved up and down. The head is joined to the body using a four bar linkage. Keep the opposite pairs of linkages in a four bar linkage parallel and all the parts move in a regimented lined up fashion. Small changes to the alignment, however, can make for more fluid looking results. Check out the animation above. In the bird on the left horizontal bars are 50mm long and the vertical bars are 30mm. The result is a straight forward parallel movement. In the bird on the right the vertical bar joining to the head is only 25mm long, all other measurements are the same. The result gives the movement just a little kick and a little more realism. I've implemented that new linkage set in card and it works nicely. Pics tomorrow.