Humanoid face utilizing rotary actuator and piezoelectric sensors

Mimicking facial structure for a robotic head is a challenging issue and requires information on design and control of muscle actuation, architecture of the linkages between actuation points within skin, and deformation matrix with respect to global coordinates for a specific expression. This manuscript presents: (1) a functional relationship between deformation vector of facial control points and actuator parameter, skin elasticity and angular position of actuator. The actuation method is applicable to any rotary actuator technology utilized for facial expressions and takes into account the skin stiffness; (2) a prototype robotic head with embedded sensor to enhance interaction ability of humanoids; and (3) characterization of various facial expressions on a prototype robotic face.