Owning Palette: State Feedback Design VIs
Installed With: Control Design and Simulation Module
Builds the state estimator based on a list of known inputs, measured outputs, the linear state-space model, and the estimator gain. The data type you wire to the Estimator Gain (L) input determines the polymorphic instance to use.
A matrix estimator gain indicates that the system is a multiple-output model. Refer to the LabVIEW Control Design User Manual for more information about building state estimators. A general system configuration for the state estimator is one where this VI appends the original model states (x) to the estimation model states (
) to represent the estimator, as shown in the following equations.
Use the pull-down menu to select an instance of this VI.
 Place on the block diagram | Find on the Functions palette |
State Estimator (Single Output)
 | Configuration specifies if this VI includes the system in the estimator or considers noise as an input of the estimator. The estimator also can be a standalone estimator.
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 | Estimator Gain (L) is the gain that premultiplies the output error to correct the model state dynamics towards the physical states of the system. | ||||||
 | State-Space Model contains a mathematical representation of and information about the model that you want to use to build the estimator. | ||||||
 | Measured Outputs lists the index numbers of all the outputs that you can measure for state estimation. The index is zero-based. By default, this VI measures all outputs. | ||||||
| Known Inputs lists the index numbers of all the inputs that are known for state estimation. The index is zero-based. By default, all inputs are known. | ||||||
 | error in describes error conditions that occur before this VI or function runs.
The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code.
Use exception control to treat what is normally an error as no error or to treat a warning as an error.
Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
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 | Estimator Model provides the state-space model for the state and output estimation given known inputs and measured outputs. | ||||||
 | error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces.
Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error.
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State Estimator (Multiple Output)
| Configuration specifies if this VI includes the system in the estimator or considers noise as an input of the estimator. The estimator also can be a standalone estimator.
| ||||||
 | Estimator Gain is the gain that premultiplies the output error to correct the model state dynamics towards the physical states of the system. | ||||||
| State-Space Model contains a mathematical representation of and information about the model that you want to use to build the estimator. | ||||||
| Measured Outputs lists the index numbers of all the outputs that you can measure for state estimation. The index is zero-based. By default, this VI measures all outputs. | ||||||
| Known Inputs lists the index numbers of all the inputs that are known for state estimation. The index is zero-based. By default, all inputs are known. | ||||||
| error in describes error conditions that occur before this VI or function runs.
The default is no error. If an error occurred before this VI or function runs, the VI or function passes the error in value to error out. This VI or function runs normally only if no error occurred before this VI or function runs. If an error occurs while this VI or function runs, it runs normally and sets its own error status in error out. Use the Simple Error Handler or General Error Handler VIs to display the description of the error code.
Use exception control to treat what is normally an error as no error or to treat a warning as an error.
Use error in and error out to check errors and to specify execution order by wiring error out from one node to error in of the next node.
| ||||||
| Estimator Model provides the state-space model for the state and output estimation given known inputs and measured outputs. | ||||||
| error out contains error information. If error in indicates that an error occurred before this VI or function ran, error out contains the same error information. Otherwise, it describes the error status that this VI or function produces.
Right-click the error out front panel indicator and select Explain Error from the shortcut menu for more information about the error.
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CD State Estimator Details
Configuration Types
There are different configurations to synthesize the estimator. These configurations are system included, system included with noise, and standalone.
The system included configuration indicates that this VI calculates the states of the system and the outputs of the system internally. You do not need to provide the system outputs as inputs of the estimator to synthesize the estimator.
The system included with noise configuration incorporates sensor noise into the system included configuration. Therefore, sensor noise is an input of the controller model. Sensor noise affects the estimated states that you use to calculate the control action.
The standalone configuration configures the estimator to accept the actual outputs of the systems as inputs for state estimation. This configuration is useful for implementing the estimator on a real-time target.
Refer to the LabVIEW Control Design User Manual for more information about building a state-space controller.
Delay Support
This VI does not support delays unless the delays are part of the mathematical model that represents the dynamic system. To account for the delays in the synthesis of the controller, you must incorporate the delays into the mathematical model of the dynamic system using the CD Convert Delay with Pade Approximation VI (continuous models) or the CD Convert Delay to Poles at Origin VI (discrete models). Refer to the LabVIEW Control Design User Manual for more information about delays and the limitations of Pade Approximation.