Actively variable stiffness and transmission mechanism based on 4-bar linkage for robots

A robot comprising:

• a main body;
• an actuation unit installed in the main body and comprising a first motor to rotate a swivel panel in forward and reverse directions at a predetermined angle;
• a link unit comprising an input link coupled in a direction intersecting with an axis of the first motor to the swivel panel so as to be able to idle, a ground link having one end coupled so as to be pivotable about the axis of the first motor, a connecting link having one end reciprocatably screwed to an outer peripheral surface of the input link and the other end disposed in a direction intersecting with the input link, and an output link having one end pivotably coupled to the other end of the connecting link and the other end pivotably coupled to the other end of the ground link;
• a swivel unit extending from the other end of the output link in its longitudinal direction by a predetermined length and swiveled at a predetermined angle when the first motor is operated in the forward and reverse directions;
• and
• a control unit configured to control a transmission ratio of the swivel unit depending on the situation by comprising a motor configured to rotate the input link in the forward and reverse directions so as to adjust a length of the input link by increasing or decreasing a distance between the axis of the first motor and one end of the connecting link.