1312 Part G Human-Centered and Life-Like Robotics 56.2.3 Different Sensors the robot will see a different world than the human.With Part G156 respect to behavior,placement of sensors on the head of Humanoid robots have made use of a variety of sen- the robot allows the robot to sense the world from a van- sors including cameras,laser range finders,microphone tage point that is similar to that of a human,which can arrays,lavalier microphones,and pressure sensors. w be important for finding objects that are sitting on a desk Some researchers choose to emulate human sensing by or table. selecting sensors with clear human analogs and mount- Prominent humanoid robots have added additional ing these sensors on the humanoid robot in a manner that sensors without human analogs.For example,Kismet mimics the placement of human sensory organs.As dis- used a camera mounted in its forehead to augment the cussed in Sect.56.6,this is perhaps most evident in the two cameras in its servoed eyes,which simplified com- use of cameras.Two to four cameras are often mounted mon tasks such as tracking faces.Similarly,versions of within the head of a humanoid robot with a configuration Asimo have used a camera mounted on its lower torso similar to human eyes. that looks down at the floor in order to simplify obstacle The justifications for this bias towards human-like detection and navigation during locomotion. sensing include the impact of sensing on natural human- robot interaction,the proven ability of the human senses 56.2.4 Other Dimensions of Variation to support human behavior,and aesthetics.For example, with respect to human-robot interaction,nonexperts can Other significant forms of variation include the size of sometimes interpret the functioning and implications of the robot.the method of actuation.the extent to which the a human-like sensor.such as a camera,more easily.Sim- robot attempts to appear like a human,and the activities ilarly,if a robot senses infrared or ultraviolet radiation, the robot performs. 56.3 Locomotion Bipedal walking is a key research topic in humanoid typically need to balance dynamically when walking robotics (see also Chap.16,Legged Robots,for a review bipedally. of this topic in the context of locomotion in general). Legged locomotion is a challenging area of robotics 56.3.1 Bipedal Locomotion research,and bipedal humanoid locomotion is espe- cially challenging.Some small humanoid robots are Currently the dominant methods for bipedal legged loco- able to achieve statically stable gaits by having large motion with humanoids make use of the zero-moment feet and a low center of mass,but large humanoids with point(ZMP)criterion to ensure that the robot does not a human-like weight distribution and body dimensions fall over [56.35].As discussed in detail in Chap.16,con- 1=0s t=2.5s 1=5s t=7.5s 1=17.5s t=15s t=12.5s t=10s Fig.56.9 HRP-2 walks on a slightly uneven surface1312 Part G Human-Centered and Life-Like Robotics 56.2.3 Different Sensors Humanoid robots have made use of a variety of sen￾sors including cameras, laser range finders, microphone arrays, lavalier microphones, and pressure sensors. Some researchers choose to emulate human sensing by selecting sensors with clear human analogs and mount￾ing these sensors on the humanoid robot in a manner that mimics the placement of human sensory organs. As dis￾cussed in Sect. 56.6, this is perhaps most evident in the use of cameras. Two to four cameras are often mounted within the head of a humanoid robot with a configuration similar to human eyes. The justifications for this bias towards human-like sensing include the impact of sensing on natural human– robot interaction, the proven ability of the human senses to support human behavior, and aesthetics. For example, with respect to human–robot interaction, nonexperts can sometimes interpret the functioning and implications of a human-like sensor, such as a camera, more easily. Sim￾ilarly, if a robot senses infrared or ultraviolet radiation, the robot will see a different world than the human. With respect to behavior, placement of sensors on the head of the robot allows the robot to sense the world from a van￾tage point that is similar to that of a human, which can be important for finding objects that are sitting on a desk or table. Prominent humanoid robots have added additional sensors without human analogs. For example, Kismet used a camera mounted in its forehead to augment the two cameras in its servoed eyes, which simplified com￾mon tasks such as tracking faces. Similarly, versions of Asimo have used a camera mounted on its lower torso that looks down at the floor in order to simplify obstacle detection and navigation during locomotion. 56.2.4 Other Dimensions of Variation Other significant forms of variation include the size of the robot, the method of actuation, the extent to which the robot attempts to appear like a human, and the activities the robot performs. 56.3 Locomotion Bipedal walking is a key research topic in humanoid robotics (see also Chap. 16, Legged Robots, for a review of this topic in the context of locomotion in general). Legged locomotion is a challenging area of robotics research, and bipedal humanoid locomotion is espe￾cially challenging. Some small humanoid robots are able to achieve statically stable gaits by having large feet and a low center of mass, but large humanoids with a human-like weight distribution and body dimensions t=17.5 s t=0 s t=15 s t=2.5 s t=12.5 s t=5 s t=10 s t=7.5 s Fig. 56.9 HRP-2 walks on a slightly uneven surface typically need to balance dynamically when walking bipedally. 56.3.1 Bipedal Locomotion Currently the dominant methods for bipedal legged loco￾motion with humanoids make use of the zero-moment point (ZMP) criterion to ensure that the robot does not fall over [56.35]. As discussed in detail in Chap. 16, con￾Part G 56.3