Mathematical Model for Binocular Movements Mechanism and Construction of Eye Axes Control System

Abstract

A binocular motor control model based on the anatomic structure and physiological function of the brainstem is proposed. The simple control system of the model can realize vergence and conjugate eye movements, including smooth pursuit, optokinetic eye movements, and vestibular oculomotor reflex. The principles of vergence and conjugate eye movements are studied by analyzing the model from the viewpoint of system control engineering. Neural structures such as crossing image feedback pathways, which are not commonly found in system control engineering, are confirmed to play an important role in binocular motor control. The relationship of the neural pathway gains is obtained from the stability conditions of the model.As an application of the proposed model, an eye axis control system structured like the synthesized binocular motor model is implemented. In this eye axis control system, some characteristics existing in human eyes but not in conventional robot eyes are confirmed, including: (1) Both eyes can easily gaze at the same point simultaneously. (2) If one eye is closed or blocked by an obstacle, it will follow the movement of the other eye so that the obstructed eye can quickly find the target viewed by the other eye when the obstacle is removed.