No angular velocity value in output of Ideal Torque Source

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I am trying to model a DC motor with components in the Foundation Library. I am trying to understand the "spe_servomotor" example. I run the example with the input given below (my signal is the one in red square).
I am checking for the angular velocity as output of the "Ideal Torque Source" in the "DC Servo Motor" subsystem after the simulation, result is given below.
It is clear that there is the angular velocity as output of "Ideal Torque Source" in the "DC Servo Motor". For double check, I add a scope like the given below and check velocity and position informations:
My system uses a PID controller to calculate the required DC motor voltage to create required torque. There is no problem with the torque calculation but there is no angular velocity as the ideal torque source output. Because of that viscous friction and shaft inertia component are useless. I want to add rotational friction component to system but since there is no angular velocity, it is useless too. I cannot find what the problem is. Thanks for your help.

Answers (1)

Joel Van Sickel
Joel Van Sickel on 6 May 2022
Your torque sensor is holding your motor stationary. The torque sensor is unecessary becuase the torque applied to the system is the torque going into the ideal torque source. If you want to place the torque sensor, it needs to be between the source, and the rest of the system. Torque is a through variable, so the system is attatched to whatever is on the other side of the torque sensor. In your case, that is a rotational reference, which holds the motor stationary. Deleting that torque sensor and outputing your calculated torque should do the trick.

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