Running the Cosimulation
1
In the Simulation toolbar, click Run to start the simulation.
You can monitor the progress in Simulink by watching the progress bar and the updates of the scope. On Windows® and Linux® operating systems, you can monitor the progress in COMSOL for each communication step in the solver progress window that appears.
The scope in the following image shows the displacement in micrometers. Since the communication time step is set to 5e-6 seconds the curve appears to have steps. It is an important part of the modeling procedure to choose a suitable communication step size to obtain a reasonable accuracy.
We will now replace the constant voltage with an on/off controller to maintain the tip displacement between 0.71 μm and 0.81 μm.
2
Delete the Constant block from the Simulink diagram.
3
Add a Relay block, and set the following parameters:
Parameters
Values
Switch on point
0.81
Switch off point
0.79
Output when on
0
Output when off
5
4
Now link the COMSOL Cosimulation block output port 1(disp) to the Relay block input port and the Relay block output port to the COMSOL Cosimulation block input port.
5
Finally add a scope to display the Relay block output port.
You can also change the name of the scope so that the Simulink diagram looks like the figure below.
6
In the Simulation toolbar, click Run to start the simulation.
The scope for the tip displacement now shows that the displacement is kept between 0.81 μm and 0.79 μm after the on/off controller has been activated.
The maximum temperature is kept between 420 K and 440 K.
The voltage scope shows the activation of the actuator.