Fig. 1.

Coordinate frame convention for the proposed RUSS. F_base stands for the robot base frame; F_flange is the flange frame to attach the end-effector; F_cam is the RGB-D camera’s frame; F_A–SEE is the US probe tip frame; (1) is the transformation from F_base to F_flange, denoted as ${\text{T}}_{\mathit{\text{flange}}}^{\mathit{\text{base}}}$; (2) is the transformation from F_flange to F_A–SEE, denoted as ${\text{T}}_{A-\mathit{\text{SEE}}}^{\mathit{\text{flange}}}$; (3) is the transformation from F_A–SEE to F_cam, denoted as ${\text{T}}_{\mathit{\text{cam}}}^{A-\mathit{\text{SEE}}}$.