So you want to change the breakaway friction torque during the simulation. I think the simplest way to do that is to create a custom component where the breakaway torque is defined as an input instead of a parameter.
- Create a copy the source code of the Rotational Friction block.
- Add a "input" section
- Move the line "brkwy_vel = { 0.1, 'rad/s' }; % Breakaway friction velocity" from the "parameter" section to the "input" section
- Add a Simscape Component block to your model, and use the modified source code.
The newly created Simscape Component will have a physical signal input that let you set the breakaway torque during the simulation.
