How to specify the rotational velocity of a torque source?

I am trying to specify the rotational velocity of a torque source but can't find the answer.

Do I place the output of an ideal rotational velocity source into the input of an ideal torque block? Or do I add them in parallel?

I've tried both but have unexpected results.

[Raghvi]

What are your expected results?

Check this out to get an idea on how to use torque source https://www.mathworks.com/help/simscape/ug/permanent-magnet-dc-motor.html

Answer 1

[Steve Miller]

If you want the shaft to spin at a specified speed, you have two options - use one or the other.

1. Use an Ideal Angular Velocity Source. This block will apply whatever torque is needed to make the shaft spin at the specified speed.
2. Use an Ideal Torque Source with a controller to adjust the torque if the shaft speed does not match the target speed. Measure the shaft speed with a Rotational Motion Sensor, subtract from the target speed to get the error, and use a PI or PID controller to specify the torque the Ideal Torque Source should apply.

You cannot specify both speed and torque. If you choose a speed, the torque may need to vary to keep the shaft at that speed. If you choose a torque, the system will accelerate or decelerate according to the other conditions in the system.

--Steve

[Geordie]

Hi Steve,

I have a similar scenario to AThomas - specifically: I'm modelling a system with known input velocity and torque on one end of a flexible coupling and a torque input on the other end of the flexible coupling. I'm attempting to model the interaction of the coupling with the second torque source (the dynamics of which are modeled elsewhere in MATLAB).

Since torque and speed are both important parameters in my simulation, is there a way to model external torque loads on a shaft operating at a given speed?

Thanks,

Geordie