Yet Another Walking Mechanism

thingiverse

This mechanism, based on the Win-Bin Shieh 8 bar linkage, is essentially a Chebyshev Lambda or plantigrade mechanism that has been inverted twice with a pantograph. The Lambda already known to have smooth and flat motion, but located above the linkage, is rotated upside down here. To invert the motion, a pantograph is used for both front and back legs, consisting of two pantographs in this case. However, the pantograph could also be used to produce larger scaled motions if desired. In this instance, I have used 1:1 scale instead. The ski that connects the front and back leg provides a wide ground contact area. Video: https://youtu.be/AfgMdyHlt1A I used a large number of screws for this project, all of which are M3 with lengths of 6 mm, 10 mm, and 15 mm. For the long axles, I employed 3 mm iron wire. The mechanism features holes with diameters of 2.8mm that need to be tapped for M3 screw use, as well as 3.2mm holes that may require drilling clean. The servo horn requires a 3 mm diameter hole at a position 1 cm from the center. Two screws fasten the horn to the crank1 part. The servo mounting holes are designed slightly wider than their real size, which is intended to compensate for shrinkage.