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initopspec - Initialize operating point specification values

Syntax

opnew=initopspec(opspec,oppoint)
opnew=initopspec(opspec,x,u)
opnew=initopspec(opspec,xstruct,u)

Graphical Interface

As an alternative to the initopspec function, initialize operating point specification values in the Create Operating Points pane in the Operating Points node within the Simulink Control Design GUI. See Computing Operating Points from Specifications.

Description

opnew=initopspec(opspec,oppoint) initializes the operating point specification object, opspec, with the values contained in the operating point object, oppoint. The function returns a new operating point specification object, opnew. Create opspec with the function operspec. Create oppoint with the function operpoint or findop.

opnew=initopspec(opspec,x,u) initializes the operating point specification object, opspec, with the values contained in the state vector, x, and the input vector, u. The function returns a new operating point specification object, opnew. Create opspec with the function operspec. You can use the function getxu to create x and u with the correct ordering.

opnew=initopspec(opspec,xstruct,u) initializes the operating point specification object, opspec, with the values contained in the state structure, xstruct, and the input vector, u. The function returns a new operating point specification object, opnew. Create opspec with the function operspec. You can use the function getstatestruct or getxu to create xstruct and the function getxu to create u with the correct ordering. Alternatively, you can save xstruct to the MATLAB workspace after a simulation of the model. See the Simulink documentation for more information on these structures.

Example

Create on operating point using findop by simulating the magball model and extracting the operating point after 20 time units.

oppoint=findop('magball',20)

This syntax returns the following operating point:

 Operating Point for the Model magball.
(Time-Varying Components Evaluated at time t=20)

States: 
----------
(1.) magball/Controller/Controller
      x: 5.28e-009    
      x: -2.56e-006   
(2.) magball/Magnetic Ball Plant/Current
      x: 6.99         
(3.) magball/Magnetic Ball Plant/dhdt
      x: -2.62e-005   
(4.) magball/Magnetic Ball Plant/height
      x: 0.05    
 
Inputs: None

Use these operating point values as initial values in an operating point specification object.

opspec=operspec('magball');
newopspec=initopspec(opspec,oppoint)

The new operating point specification object is displayed.

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

States: 
----------
(1.) magball/Controller/Controller
      spec:  dx = 0,  initial guess:     5.28e-009
      spec:  dx = 0,  initial guess:    -2.56e-006
(1.) magball/Magnetic Ball Plant/Current
      spec:  dx = 0,  initial guess:          6.99
(1.) magball/Magnetic Ball Plant/dhdt
      spec:  dx = 0,  initial guess:    -2.62e-005
(1.) magball/Magnetic Ball Plant/height
      spec:  dx = 0,  initial guess:          0.05
 
Inputs: None
 
Outputs: None

You can now use this object to find operating points by optimization.

See Also

findop, getstatestruct, getxu, operpoint, operspec

getxu

linearize

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