Change internal mechanics of a prismatic joint during a simulation

I have a simscape model that using a prismatic joint. During a simulation, i want to modeify my damping coefficient. But looks like i can't modify it during the simulation. Is there a way i can do this, or can i modify the prismatic joint source code to make my own prismatic joint block?

Answer 1

[Sahas]

Hi @Limeng,

As per my understanding, you would like to modify the "Damping Coefficient" of the "Prismatic Joint" in the model during simulation.

One way to achieve this is by using the "Variable Translational Damper" block in Simscape and connecting it to the Prismatic Joint. You can use the "Translation Multibody Interface" block to link the Simscape circuits to Simscape Multibody joints based on the model.

Refer to the following MathWorks documentation links for more information on "Variable Translational Damper", "Translation Multibody Interface" blocks and steps to connect Simscape networks to Simscape Multibody joints:

• https://www.mathworks.com/help/sdl/ref/variabletranslationaldamper.html
• https://www.mathworks.com/help/simscape/ug/connecting-simscape-networks-to-simscape-multibody-joints.html
• https://www.mathworks.com/help/simscape/ref/translationalmultibodyinterface.html

I hope this is beneficial!

[Limeng]

Thank you very much!

Answer 2

[Dhruv]

In Simscape, modifying parameters like the damping coefficient of a Prismatic Joint during a simulation can be challenging because Simscape typically requires parameters to remain constant throughout the simulation. However, you can try implementing one of the following approaches:

• Custom Damping Force: Create a custom damping force using a MATLAB Function block that varies with time or other simulation conditions. This allows you to calculate the damping force based on the desired damping coefficient at each time step. Refer to the following link for more information: https://www.mathworks.com/help/simulink/slref/matlabfunction.html
• Simulink Events: Consider using Simulink events to trigger changes in the damping value if the change is event-driven (e.g., at specific simulation times or conditions). You can implement this using Stateflow. For more details, I recommend going through the following documentation: https://www.mathworks.com/help/simulink/mdl_gd/maab/using-simulink-and-stateflow-in-modeling.html

I hope this helps!

[Limeng]

Thnak you very much!