torque sensed by a motion does not create the same motion!!!

We modeled two links connected to a revolute joint which is fixed on the ground. We implemented a sine wave motion to the first joint with frequency of 1 and amplitude of 1. Angular velocity and acceleration are both applied as well. We used a joint sensor to sense the applied torque and we applied this torque to an another identical link. Interestingly, the output motion of the second link is not sinusoidal. What do you think the problem is? All CSs are set to World.