Recent technological advances in legged robots are opening up a new era of mobile robotics. In particular, legged robots have a great potential to help during disaster situations or with elderly care services. To allow for dynamic physical interactions with environments, the hardware/software design requirements of mobile robots differ from manufacturing robots (which are designed for maximum stiffness to allow for accurate and rapid position tracking without contact). Events such as the Fukushima power plant explosion highlight the need for robots that can traverse various terrains and perform dynamic physical tasks in unpredictable environments. Kim will discuss the new mobile robot design paradigm, the control algorithms for Cheetah robot version 2 and version 3, and the role of bio-inspiration in designing legged robots. Finally, Kim will compare solutions from both an engineering and biological perspective.