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Specifying Completely Known Operating Points

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Workflow for Specifying Completely Known Operating Points Creating an Operating Point Object Changing Operating Point Values

Workflow for Specifying Completely Known Operating Points

To use functions to specify completely known operating points

1. Create an operating point object.

2. Make changes to the object values.

This section continues the example from Example: Water-Tank System. At this stage in the example, linearization point objects have been created in the MATLAB workspace. See Selecting Inputs and Outputs for the Linearized Model for more information on creating linearization point objects.

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Creating an Operating Point Object

An operating point object contains information about your system's states and inputs at the operating point. When you know your operating point explicitly, use the function operpoint to create an operating point object for your model.

For example, to create an operating point object for the water-tank model, type

watertank_op=operpoint('watertank')

MATLAB software displays

Operating Point for the Model watertank.
 (Time-Varying Components Evaluated at time t=0)

States: 
----------
(1.) watertank/PID Controller/Integrator
      x: 0            
(2.) watertank/Water-Tank System/H
      x: 1            
 
Inputs: None 
----------

Within the operating point object are objects for all the states and inputs in the model. Each of these objects has a property called x, or u in the case of inputs, that gives the value of that state or input.

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Changing Operating Point Values

Change the x and u properties of the operating point object to known values at the operating point. For example, to change the value of the first state to 1.26 and the second state to 10, type

watertank_op.States(1).x=1.26, watertank_op.States(2).x=10

which returns

Operating Point for the Model watertank.
 (Time-Varying Components Evaluated at time t=0)

States: 
----------
(1.) watertank/PID Controller/Integrator
      x: 1.26         
(2.) watertank/Water-Tank System/H
      x: 10           
 
Inputs: None 
----------

The operating point object, watertank_op, now contains the known operating point of the system.

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Computing Operating Points from Specifications

Extracting Values from Simulation

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