When to Specify Initial States Versus Estimate Initial States

Sets of measured data are often collected at various times and under different initial conditions. When you estimate model parameters using one data set and subsequently run another estimation with a second data set, your parameter values may not match.

You can use theParameter Estimatorto estimate the initial conditions using procedures that are similar to those you use to estimate parameters. You can then use these initial condition estimates as a basis for estimating parameters for your Simulink^®model.

Specify Model Initial States

After you select parameters for estimation, as described inSpecify Parameters for Estimation, you can specify initial conditions of states in your model. By default, the estimation uses initial conditions specified in the Simulink model. If you want to specify initial conditions other than the defaults, use theInitial Statespanel in the experiment editor dialog. For this example, right clickNewDataand selectEdit...from the list to open theexperiment editor. Then, click选择初始状态button.

The Select Model States dialog for theengine_idle_speedmodel looks like

Click the check box next to the state you would like to modify. For example, if you selectengine_idle_speed/Transfer Fcnand enter the initial values-0.2and0,Initial Statespanel now looks like

ClickSelect Parametersin theParameter Estimationtab. After you also select the parameters as described inSpecify Parameters for Estimation,Edit: Estimated Parameters dialog looks like the following figure.