Simulink Control Design™ - MathWorks

(Tuis.) #1

Compute Steady-State Operating Points


Steady-State Operating Point Search (Trimming)


You can compute a steady-state operating point (or equilibrium operating point) using
numerical optimization methods to meet your specifications. The resulting operating point
consists of the equilibrium state values and corresponding model input levels. A
successful operating point search finds an operating point very close to a true steady-
state solution.

Use an optimization-based search when you have knowledge about the operating point
states and the corresponding model input and output signal levels. You can use this
knowledge to specify initial guesses or constraints for the following variables at
equilibrium:


  • Initial state values

  • States at equilibrium

  • Maximum or minimum bounds on state values, input levels, and output levels

  • Known (fixed) state values, input levels, or output levels


Your operating point search might not converge to a steady-state operating point when
you overconstrain the optimization by specifying:


  • Initial guesses for steady-state operating point values that are far away from the
    desired steady-state operating point.

  • Incompatible input, output, or state constraints at equilibrium.


You can control the accuracy of your operating point search by configuring the
optimization algorithm settings.

Steady-State Operating Point from Simulation Snapshot


You can compute a steady-state operating point by simulating your model until it reaches
a steady-state condition. To do so, specify initial conditions for the simulation that are
near the desired steady-state operating point.

Use a simulation snapshot when the time it takes for the simulation to reach steady state
is sufficiently short. The algorithm extracts operating point values once the simulation
reaches steady state.

1 Steady-State Operating Points

Free download pdf