Some survey on passive dynamic walking

The focus of the work is a review on the development of the passive dynamic walking. The passive dynamic walking has distinguished advantages compared with other methodologies in robotics, mainly because that the passive dynamic robotics focuses on and exploits the dynamics of the mechanisms of the biped robot. In addition, the development of passive dynamic walkers is introduced. Control strategies are necessary to improve the stability and robustness of locomotion of passive dynamic walkers, such as the slope invariant control, the energy based control and the learning control, are discussed briefly. Finally, the unresolved problems in the field of the passive dynamic walking are summarized, and directions of further developments are discussed.