I have the Simscape and Simscape Multibody toolboxes, from this I have generated a model of a stepper motor (just the motor with something on the shaft, so I can tell if it is spinning or not). What I'm trying to do, is link the actuator torque of the model to an electrical/mechanical system, so I can then start to create a closed loop for it.
Just to check that everything is working, I've linked the torque input of the Multibody model to a constant value, and I see that the angles and velocities increase very quickly (as torque affects the acceleration). What I don't get is, if I configure the input of the actuator such that it is based on position and have this position ramping up (at a constant angular velocity), I see that the "sensed" torque is a sine wave - shouldn't this be zero (after the initial speed "up-phase") Is anyone able to explain what I am seeing? As this doesn't make sense to me...