Humanoid Robot With Imitation Ability

This chapter designs an intelligent humanoid robot that not only can walk forward, backward, turn left, turn right, walk sideward, squat down, stand up and bow smoothly, but also can imitate several human basic motions. The robot’s structure is composed of 17 AI motors with some selfdesign acrylic sheets connections. The robot is like a human in that it also has two hands, two feet, and a head. The head is a web camera which serves as its eye of the robot. The eye can recognize the color marks pasted on the human body in any complex background. The robot can recognize and imitate human motions according to the relative positions of those marks. The imitated human motions include the various motions of the hand and the lower body, such as “raise hand”, “Stand up”, “Squat down”, and “Stand on one foot”. Furthermore, the robot can also imitate “walking forward”, “walking backward” and “walking sideways”. The webcam automatically rotates to search the marks pasted on the human when they move outside the robot’s vision. Notably, the stability and balance of the robot should be maintained, regardless of the motion performed by the robot. Humanoid biped robots have been widely studied. Those investigations always focus on keeping balance control and walking as smoothly as possible. Zero Moment Point (ZMP) concept has been used to implement the balance control for the biped robot (Erbatur et al., 2002), (Kim & Oh, 2004) and (Park & Chung, 1999). The paper (Kanehiro et al., 1996) developed a walking pattern generator and a gravity compensation function to enable the biped robot to walk and carry objects. (Grizzle et al., 2001) established the existence of a periodic orbit in a simple biped robot, and analyzed its stability properties. A biped robot has been designed in (Loffler et al., 2004) to achieve a dynamically stable gait pattern, allowing for high walking velocities. A walk control for biped robots, consisting of a feed forward dynamic pattern and a feedback sensory reflex, has also been proposed in (Huang & Nakamura, 2005). (Sias & Zheng, 1990) proposed the number of degrees of freedom corresponding to robot motions. For instance, each foot should have four degrees of freedom at least for the basic walking of a biped robot and should have five degrees of freedom at least for walking up stairs and down stairs. A robot can turn and walk smoothly on the ground with six degrees of freedom per foot, and can walk with a large step given seven degrees of freedom per foot. Furthermore, a robot needs at least eight degrees of freedom per foot to walk like a human being. The above information is helpful for the robot designers when determining the number of degrees of freedom of a robot.