An example robot includes: a motor disposed at a joint configured to control motion of a member of the robot; a transmission including an input member coupled to and configured to rotate with the motor, an intermediate member, and an output member, where the intermediate member is fixed such that as the input member rotates, the output member rotates therewith at a different speed; a pad frictionally coupled to a side surface of the output member of the transmission and coupled to the member of the robot; and a spring configured to apply an axial preload on the pad, wherein the axial preload defines a torque limit that, when exceeded by a torque load on the member of the robot, the output member of the transmission slips relative to the pad.