Benchmarking human likeness of bipedal robot locomotion: State of the art and future trends

The difficulty of quantitatively defining human likeness is a well-known problem in bipedal robotics. This chapter reviews methods and criteria for the assessment of the sensorimotor mechanisms involved in human walking and posture. We focused on the potential of the reviewed methods to be used as benchmarks for human-like locomotion of bipedal robots. For walking condi-tions, several criteria and methods related to dynamic similarity, passivity and dynamicity, static stability, and energy consumption have been identified. As for standing functions, we identified the most relevant features characterizing the human postural sensorimotor mechanisms and presented the experimental protocols currently used to evaluate the human-like robotic performance. Fur-thermore, we discussed how the current robotic competitions such as RoboCup and DARPA Robotics Challenges can contribute to the identification of relevant benchmarks. Finally, we speculated about the importance of international consensus on the quantitative definition of human likeness and suggested some future actions for improving collaboration and standardization within the scien-tific community.