Hybrid RobOstrich Manipulator with Intrinsic and Extrinsic Actuations

Ostrich neck-inspired manipulators have attracted attention in the field of bio-inspired robotics. They achieve unique movements that are difficult for conventional robots, owing to their flexibility. However, it is difficult to mimic the length, mass, and actuation redundancy of ostrich necks. This is because the longer and heavier the robotic arm, the greater is the load on the joints. Furthermore, if a robotic arm exhibits actuation redundancy, its structure and control become more complex. In this study, we developed a hybrid RobOstrich manipulator with both intrinsic and extrinsic actuations. This is the third-generation of the RobOstrich series. The manipulator consists of a servomotor attached to each joint that performs intrinsic actuation and two servomotors on the base that perform extrinsic actuation through wires. We conducted an experiment to reproduce the rolling pattern, which is a unique movement of the ostrich neck, to verify the effect of hybrid actuation. The results indicated that the joint angle error and required torque were reduced by applying hybrid actuation.