Optimal design of a parallel bionic eye mechanism

Abstract

To obtain a large viewing angle and fast, smooth tracking of the target for a robot in an unknown environment, the vertebrate extraocular muscles are imitated in this paper, the configuration with a large field of view and high motion precision is studied, and then, a smallsized "inverted-tricept" parallel bionic eye mechanism is designed. For the "inverted-tricept" mechanism, the large inclination will make the mechanism more "slender", whereas the high precision requires the mechanism to be "stout". Thus, there is a contradiction between these two indexes. To ensure a large field of view and high eye movement accuracy simultaneously, the non-dominated sorting-based genetic algorithm-II (NSGA-II) is adopted under the constraints of the overall dimensions, driver stroke and hinge deflection to optimize the moving platform inclination and kinematic performance. Thus, the structural parameters are obtained. According to the optimization results, the dynamic simulation analysis of the system is conducted, and the rationality of the structural parameters is verified. In addition, the experimental prototype is built accordingly. It is shown from the actual measurement results that the designed parallel bionic eye has a distortion-free field of view of up to 200.95° and an eye movement accuracy of 0.01°, which lay a foundation for the wide range search and high-precision ranging of the subsequent binocular stereo vision system.