Incremental development of a passive-dynamics-based walking machine

Passive-dynamic walkers are mechanical devices that walk down a slope without motors or controllers. In this paper we present in detail the incremental development of one such walker, the design stages we went through and its experimental results. We built a four-legged planar passive-dynamic walking machine with its inner and outer legs connected rigidly two by two, making it equivalent to a biped machine in terms of dynamics. We conducted our experiments with two different knee designs: first, with a magnetic knee-locking mechanism, and the second, with a knee-locking mechanism featuring active release. Both mechanisms were designed in an attempt to create a simpler and easier to adjust knee-locking mechanism, instead of the more common knee-locking via suction cups mechanism. We conducted series of experiments in which we counted the steps the walker made while walking down an incline. We compared the results achieved with the two knee-locking mechanisms and assessed their effectiveness. The second model made an increased number of successful walks down the slope from which we concluded that the newer active release mechanism is more reliable and easy to use and set up.