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Specify Known Initial States

When to Specify Initial States Versus Estimate Initial States

Often, sets of measured data are 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. Given that the Simulink® Design Optimization™ software attempts to find constant values for parameters, this is clearly a problem.

You can 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. The Control and Estimation Tools Manager has an Estimated States pane that lists the states available for initial condition estimation.

How to Specify Initial States in the GUI

After you select parameters for estimation, as described in Specify Parameters to Estimate, 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 the State Data tab. You can select the State Data tab in the New Data node under the Transient Data node in the Workspace tree.

To specify the initial condition of a state for the engine_idle_speed model:

  1. Select the Data cell associated with the state.

  2. Enter the initial conditions. In this example, enter -0.2 for State - 1 of the engine_idle_speed/Transfer Fcn. For State - 2, enter 0.

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