Extra-ocular Muscles for Robotic Eye and its Control Design for Real-Time Stimulus Tracking

For coordination and communication in human-robot interaction within a social environment, fast camera sensor movement is crucial for stimulus tracking. This paper proposes bio-inspired extra-ocular muscles for humanoid robotic eyes to achieve a high decoupling ratio between the camera sensor and the robotic head skeleton. The extra-ocular muscles, based on a gimbal system, offer effective decoupling and enable the camera sensor (ESP32 CAM) to be mounted within the inner channel, resembling the human eyeball in the extra-ocular muscles. The high decoupling ratio provided by the gimbal system makes the robotic eye more suitable for fast real-time stimulus tracking. The implemented control system allows for both automatic target tracking and manual control using commands. A comparison between the human and robotic eyes, including structure, mechanical design, and tracking mechanism, demonstrates the suitability of the proposed extra-ocular muscles for humanoid robots. A short video demonstrating real-time stimulus tracking by the robotic eye is provided as well.