1. Liu J, Tan M, Zhao X G. Legged robots-an overview. Trans Inst Meas Control, 2007, 29(2): 185–202
2. Silva M F, Machado J A T. A historical perspective of legged robots. J Vib Control, 2007, 13(9–10): 1447–1486
3. Nozaki K, Murakami T. A motion control of two-wheels driven mobile manipulator for human-robot cooperative transportation. In: Proceedings of 35th Annual Conference of the IEEE Industrial Electronics Society, Porto, 2009. 1574–1579
4. Nakajima S. Concept of a novel four-wheel-type mobile robot for rough terrain, RT-mover. In: Proceeding of IEEE/RSJ International Conference on Intelligent Robots and Systems, St. Louis, 2009. 3257–3264
5. Bares J E, Wettergreen D S. Dante II: Technical description, results and lessons learned. Int J Robot Res, 1999, 18(7): 621–649