Error using Unbalanced load to simulate DC motor rotor imbalance

Hi everyone,

I am attempting to use the Unbalanced Load Simscape block to model rotor imbalance in a motor. This can be simulated by adding an unbalanced mass or by modifying the rotor’s inertia.

As shown in Figure 1, I have connected the unbalanced load to the motor output. However, when I run the simulation, I encounter an error, which is displayed in Figure 2.

Thank you in advance!

Answer 1

[MULI]

Hi @M.Sattar,

• The issue is likely due to a rigid connection between the DC motor and the mechanical load (unbalanced load).
• This rigid setup can cause initialization errors in Simscape because the solver struggles with perfectly stiff systems.
• To fix this, you can add compliance by inserting a "Rotational Spring" and "Rotational Damper"
• Connect these between the motor's R port and the unbalanced load.
• This will allow some mechanical flexibility and help the solver initialize the system correctly.

For more information on this you can refer to the below links and also the examples mentioned:

https://www.mathworks.com/help/releases/R2024b/simscape/ref/rotationaldamper.html

https://www.mathworks.com/help/releases/R2024b/simscape/ref/rotationalspring.html

[M.Sattar]

Hi @MULI. Thank you for your respone!

Unfortunately I tried your suggestion, but I am still facing the same error