Elastic body having variable rigidity, and actuator module including same

An actuator module, comprising:

• a motor;
• a gear module connected to the motor;
• an output unit acting on an external load;
• a variable-stiffness elastic body configured for transmitting power from the gear module to the output unit, the variable-stiffness elastic body comprising:
• a link portion configured to receive torque from the gear module or the output unit, and
• a spring portion connected to the gear module or the output unit that is not connected to the link portion in order to receive torque therefrom, the variable-stiffness elastic body having stiffness that varies due to contact between the link portion and the spring portion when deformed by torque;
• and
• a sensor configured to sense deformation of the spring portion,
• wherein the spring portion comprises:
• a central body connected to the gear module or the output unit to receive torque therefrom;
• a connection portion extending outwards from the central body;
• and
• a deformable portion extending from an outer end of the connection portion along a circumference of the central body, the deformable portion being bent multiple times so as to repeatedly approach and move away from the central body, the link portion being integrally connected to the deformable portion,
• wherein the connection portion includes a plurality of bars each having a substantially straight elongated body, and
• wherein the link portion radially extends from a circumference of the deformable portion toward the central body.