Design and Simulation of a Biped Locomotor with Walking and Turning Operation Libo Zhou 1 , Mingfeng Wang 1, 2, 3 , Marco Ceccarelli 4 1 School of Mechanical and Electrical Engineering, Central South University, 410083, Changsha, Hunan, China 2 State Key Laboratory of High-Performance Complex Manufacturing, Central South University, 410083, Changsha, Hunan, China 3 Rolls-Royce UTC in Manufacturing and On-Wing Technology, University of Nottingham, NG7 2GX, Nottingham, United Kingdom 4 LARM: Laboratory of Robot Mechatronics , University of Rome Tor Vergata , 00185, Rome, Italy Abstract. A study on the mechanical design and walking and turning operation of a biped locomotor is presented in this paper. The biped locomotor consists of two identical 3 degree-of-freedom (DOF) tripod leg mechanisms and a turning waist mechanism. Gait analysis in terms of straight walking and turning is per- formed by coordinating the motions of the two legs and waist mechanisms. A 3D CAD model is elaborated in SolidWorks ® environment to characterize a feasible mechanical design of the proposed biped locomotor and a corresponding dy- namic model is built in the MSC.ADAMS ® environment to evaluate the walking and turning performance of the proposed gait. Simulation results show that the proposed biped locomotor performs a practical and feasible walking and turning motion on flat surfaces with reasonable actuation forces of linear actuators and limited reaction forces between its feet and the ground. Keywords: Biped Locomotor, Gait Analysis, Dynamic Simulation. 1 Introduction Biped locomotors, as a hot topic in the legged walking machines, have attracted the interest of many research communities in the past decades [1]. Most of the existing biped walking robots are developed as based on the idea of “function bionics” and uti- lize a tandem leg mechanism with six DOFs to realize the walking mechanism, such as ASIMO [2], WALK-MAN [3], ATLAS [4], and so on. However, compared with serial mechanisms, parallel mechanisms are well known for having better performance in terms of dynamic behavior, accuracy, and ratio of payload to own weight, and they have been widely studied in both the industry and academia [5, 6]. Nevertheless, there are very few works investigating parallel mechanisms for leg designs in biped locomo- tors, especially those with less than six DOFs. WL-16 (Waseda Leg-No.16), the world’s first dynamic biped walking locomotor carrying an adult human, is based on leg designs T. Uhl (ed.), Advances in Mechanism and Machine Science, Mechanisms and Machine Science 73, https://doi.org/10.1007/978-3-030-20131-9_230 2329 © Springer Nature Switzerland AG 2019