Modeling, design and analysis of a biomimetic eyeball-like robot with accommodation mechanism

This paper presents a prototype design and system analysis of a novel biomimetic eyeball-like robot (BEBOT) with mechanism implementing the process of accommodation. The mechanism proposed is inspired by the evidence of anatomy results of human eyeball, which has the ability to percept visual information of target object from far to near distance clearly. BEBOT implements this function by bio-inspired design with annular piezoelectric actuators (PZT) stack and adaptive lens system (ASL). Anterior side of ALS is a plano-convex lens fixed on the body of robotic eyeball, while posterior side includes liquid sealed by motion platform with soft optical membrane. With proposed mechanism, the surface of posterior side deformed as the cap of sphere in different radius accordingly to the displacement of PZT actuator. Variation of the curvature represented by the radius is equivalent to the adaption of focal length in perspective of optical system. Thus, targets in a variable range of distance are projected on artificial retina based on vision sensor. Firstly, the simplified model for human eyeball is described based on anatomical research and bionic engineering. And then, detailed designs of the prototype and system architecture are illustrated either. Finally, the characteristic analysis of mechanism and optical properties are illustrated.