Construction of a Translating Link for a Leg Mechanism
This video starts with a four-bar linkage with a coupler curve that is to be used as the foot trajectory for a leg mechanism. It presents a Geogebra construction of two additional bars, one of which is connected to the coupler point and moves without rotating. This means the bar can be expanded into a leg that places the desired coupler curve where the designer specifies. This is described in Chapter 4 of Kinematic Synthesis of Mechanism.