An artificial joint with a knee axis including a swing-phase control means having a variable friction-based swing-phase controller. The variable friction-based swing-phase controller may apply different resistances at different ranges of motion by altering the torque applied upon the knee axis by altering any combination, or all of the following: the length of a lever arm and a force applied. This may be done to optimize the swing-phase control of the artificial joint to promote natural and smooth walking gait.