US Patent 11750121 Fault tolerant multiple rotary actuator assembly

An actuator assembly comprising an output member rotatable about a center axis relative to a structure, a first actuator having a first stator fixed to the structure and a first rotor rotatable about the center axis relative to the first stator, a second actuator having a second stator coupled to the first rotor such that the second stator rotates about the center axis relative to the first stator with rotation of the first rotor about the center axis and having a second rotor rotationally coupled to the output member, a controller configured in a failure mode to drive one of the first actuator or the second actuator to selectively control the rotation of the output member about the center axis with an operational failure of the other of the first actuator or the second actuator.