Design optimization of hybrid actuation combining macro-mini actuators

A significant challenge in the development of human-safe robots is how to optimize performance while maintaining high safety standards. One promising solution is a hybrid actuation concept which combines low-frequency and high-frequency actuators. However, actuator sizing of the hybrid actuation is a difficult proposition, since motor torque capacity significantly affects robot control performance and safety. Deriving an analytical model of the hybrid actuation, we propose a design methodology to determine an optimal actuator size, which provides a combination of high control bandwidth and low impedance. Our simulation and experimental results validated the proposed methodology showing that the obtained actuator parameters from the methodology improved control bandwidth while keeping effective inertia minimum.