How can I change the parameters of a Simulink model during simulation?

I have a Simulink model. Now, I'd like to quickly test a set of parameter values used in the model and observe the effects. How can I change the parameters of a Simulink model during simulation?

Answer 1

[MathWorks Support Team]

There are many ways to achieve it, depending on your use case:

1. Saving and restoring the simulation state as the 'SimState':

The Simulink 'SimState' feature allows you to save all run-time data necessary for restoring the simulation state of a model. A SimState includes both the logged and internal state of every block (e.g., continuous states, discrete states, work vectors, zero-crossing states) and the internal state of the Simulink engine (e.g., the data of the ODE solver). Note: Since R2019, 'Save complete SimState in final state parameter' was renamed to 'Save final operating point'.

Please refer to the following documentation link to learn more about the functionality:

Save final operating point - Option to save complete model operating point when simulation is paused or stopped

2. Tunable Block Parameters:

Simulink lets you change the values of many block parameters during simulation. Such parameters are called tunable parameters. You can tell whether a particular parameter is tunable by examining its edit control in the block's dialog box or Model Explorer during simulation. You can also tune a parameter at the MATLAB command line, using either the "set_param" command or by assigning a new value to the MATLAB workspace variable that specifies the parameter's value. Note: You must update the model diagram after you change the value of a workspace variable; using "set_param" does not require this.

Refer to the following documentation link to learn more about using tunable parameters:

Tune and Experiment with Block Parameter Values

3. Simulink.Parameter:

This class enables you to create workspace objects that you can then use as the values of block parameters (for example, the value of the "Gain" parameter of a Gain block). You can create a Simulink.Parameter object in the base workspace, a model workspace, or a Simulink data dictionary. Note: You also have to update the model diagram after you change the value of a Simulink.Parameter.

Refer to the following documentation link to learn more about 'Simulink.Parameter':

Simulink.Parameter - Store, share, and configure parameter values 

If a block parameter needs to be evaluated (and changed if needed) at every simulation time step, a programmatic way of stepping through the simulation is to use the following command in a loop:

>> set_param(modelName, 'SimulationCommand', 'step');

Users can also employ event listeners to make parameter modifications only when certain events happened. Below is an example:

Accessing Block Data During a Simulation » Guy on Simulink - MATLAB & Simulink