I hope readers of this forum are aware of Joint torque feedback (JTF) control. In simple words, JTF compensates for non-linear link dynamics of a mechanical manipulator by measuring torque between the actuator rotor and the link. For more information, you can have a look at the following paper:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.48.8860
In this paper the input to the system is the torque generated by the actuator/motor and the output is the torque sensor signal. The difference of these two torques give the dynamics of the rotor (NOT THE LINK). My question is, if the rotor and the link are rigidly connected to each other, shouldn't the torque generated by the motor and torque sensed by the torque signal be equal provided there is no joint friction?