Electromagnetic actuator , comprising: - a motor shaft defining an output axis of the motion of said actuator , - a rotor connected integrally to said motor shaft and movable in response to the application of a first magnetic field, - a first stator configured to generate said first magnetic field proportionally to a first electrical signal in such a way as to move said rotor and including a first wall , - a second stator including a second wall defining with said first wall a chamber including at least part of said rotor , and containing - at least one magnetorheological fluid housed in at least part of said chamber , - said rotor comprising a partition wall configured to divide said chamber into a first portion defined between said first wall and said partition wall and into a second portion defined between said partition wall and said second wall , - said partition wall magnetically isolating said first portion and said second portion , - said magnetorheological fluid being housed in said second portion , and - said second stator also being configured to generate a second magnetic field in proportion to a second magnetic field in such a way as to vary, on command, the viscosity of said magnetorheological fluid and therefore the compliance of said actuator ; characterized by the fact that - said first wall includes a plurality of said first coils ; and said first coils are concentric with respect to a reference center, housed in distinct and separate positions of said first wall and independently controllable so that said the first magnetic field can move said rotor around a plurality of rotation axes passing through said center of reference and distinct from said output axis so that said output axis also rotates. - a motor shaft defining an output axis of the motion of said actuator , - a rotor connected integrally to said motor shaft and movable in response to the application of a first magnetic field, - a first stator configured to generate said first magnetic field proportionally to a first electrical signal in such a way as to move said rotor and including a first wall , - a second stator including a second wall defining with said first wall a chamber including at least part of said rotor , and containing - at least one magnetorheological fluid housed in at least part of said chamber , - said rotor comprising a partition wall configured to divide said chamber into a first portion defined between said first wall and said partition wall and into a second portion defined between said partition wall and said second wall , - said partition wall magnetically isolating said first portion and said second portion , - said magnetorheological fluid being housed in said second portion , and - said second stator also being configured to generate a second magnetic field in proportion to a second magnetic field in such a way as to vary, on command, the viscosity of said magnetorheological fluid and therefore the compliance of said actuator ; characterized by the fact that - said first wall includes a plurality of said first coils ; and said first coils are concentric with respect to a reference center, housed in distinct and separate positions of said first wall and independently controllable so that said the first magnetic field can move said rotor around a plurality of rotation axes passing through said center of reference and distinct from said output axis so that said output axis also rotates. <EOS>