A distributed and scalable electromechanical actuator for bio-inspired robots

Bio-inspired robots require agility, low transportation cost, and ability to operate in an unstructured environment. Although existing robots exhibit wide ranges of motion, their performance is limited by actuators. Often the robot design involves adapting a conventional motor with appropriate gears, linkages, and joints to execute high-level motion planning. The procedure leads to complex mechanical designs, low actuation speed, and poor backdrivability. This paper proposes an approach to create a modular and scalable electromechanical actuator that trades off force with allowable displacement. The stacked-actuator structure allows the whole system to share the magnetic flux path. This configuration simplifies mechanical design and assembly while improving thermal management. Stacking several actuators enables a distributed actuation mechanism suitable for creating limited-displacement motions, as in an animal spine. Analytical modeling and design, finite element analysis based simulation, and experimental results of the stacked architecture validate its feasibility to reproduce animal-like motions.