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This review is the result of a joint reflection carried out by researchers in the fields of robotics and automatic control on the one hand and neuroscience on the other, both trying to answer the same question: what are the functional bases of bipedal locomotion and how can they be controlled? The originality of this work is to synthesize the two approaches in order to take advantage of the knowledge concerning the adaptability and reactivity performances of humans and of the rich tools and formal concepts available in biped robotics. Indeed, we claim that the theoretical framework of robotics can enhance our understanding of human postural control by formally expressing the experimental concepts used in neuroscience. Conversely, biological knowledge of human posture and gait can inspire biped robot design and control. Therefore, both neuroscientists and roboticists should find useful information in this paper.

This paper concerns the simultaneous synthesis and control of walking gaits for biped robots. The goal is to propose an adaptable and reactive control law for two-legged machines. The problem is addressed with human locomotion as a reference. The starting point of our work is an analysis of human walking from descriptive (biomechanics) as well as explicative (neuroscience and physiology) points of view, the objective being to stress the relevant elements for the approach of robot control. The adopted principles are then: no joint trajectory tracking; explicit distinction and integration of postural and walking control; use of evolutive optimization objectives; on-line event handling and environment adaptation and anticipation. This leads to the synthesis of an original control scheme based on non-linear model predictive control: Trajectory Free NMPC. The movement is specified implicitly through coherent physical inequality constraints. Dynamic model and internal limitations of the system are part of the problem constraints. This work is validated by simulation results obtained for the Bip and Rabbit biped robots in various walking and standing situations and compared to human data recorded in these same situations. [Copyright &y& Elsevier]

This paper presents an experimental approach to the problem of designing and executing walking gaits on a dedicated 2-legged machine. We have oriented all our approach towards the experimental analysis of large pattern of walking gaits. This work has lead to the first experimental results obtained on the Bip anthropomorphic robot. The desired movements are designed off line using a model of the robot and tracked on the real system by means of a simple control law. The success of our approach is due both to an efficient mechatronic architecture and to the way it is used to achieve the goal of experimenting walking. The paper presents the system architecture, from mechanical to software issues and also describes the approach developed for designing and executing locomotion. Several results validate the accuracy of our modelling and exhibit the robustness and the efficiency of our controller architecture. We also present and evaluate one of the gaits realized with Bip, using both robotic and biomechanical criteria. [Copyright &y& Elsevier]