Elastic rotary actuator

A rotary actuator comprising:

• a final output member rotatable about an axis of rotation;
• a motor unit designed to drive the final output member for rotation about said axis of rotation;
• and
• an elastic unit arranged between the motor unit and the final output member and having an input member torsionally coupled to the motor unit and an output member rigidly connected for rotation with the final output member,
• wherein the elastic unit comprises an elastic element and a hypocycloid mechanism designed to convert a relative rotation of the input member with respect to the final output member about said axis of rotation into elastic deformation of said elastic element along a direction of deformation, in such a way that the deformation of said elastic element varies in a non-linear manner depending on said relative rotation.