Humanoid stereo head with augmented mobility

The paper presents a new parallel-hybrid architecture, called ArmillEye, used to realize a humanoid stereo head with vergence, with augmented mobility and augmented dynamic performance. Two cameras are supported by a parallel system of thin links providing 2 rotational mobilities to each camera. The four mobilities are coupled so that the overall degree of freedom (dof) is 3: the same pan-tilt-vergence scheme of the human vision system but the cameras have the same vergence axis of rotation instead than two separate axes. Compared to the stereo heads with serial-branched architectures normally used, the new head has: i) minimum degree of freedom because the eye and neck mobilities are integrated; ii) high dynamics because all the actuators are fixed to the base and the inertia of the mobile links and cameras is small; iii) a large view-space with 2pi pan angular span, 2pi/3 tilt angular span and vergence from very close to infinity with divergent view possible. A prototype of ArmillEye was realized and a detailed description of the robotic architecture is provided. The kinematics of the system is briefly outlined