blockSmoothN
N-th order exponential smooth with constant averaging time
Extends from Interfaces.PartialConverters.SmoothSISO (Smooth-like converter).
Information
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A smooth is an exponential information delay. It is typically used to model time lags in forming an expectation or in perceiving some information. A smooth of order n is modeled as a cascade of n first-order exponential smooth components, where the output of a preceding component is the input for its successor. The delay time for each smooth in the cascade will be delayTime/n.
Notes
- The
delayTimegiven (either as constant parameter or continuous signal) will effectively be clipped to a minimum value ofn × modelSettings.dt. The delay time for any first-order smooth in the cascade can thus never become smalle thandt, which denotes the minimum process time anywhere in the model. - In the system dynamics community a smooth is an information delay (as opposed to a material delay) [1, Appendices E and H]. Information delays model the process of updating information to the actual value. Since the technical procedure is called exponential smoothing, the name smooth has prevailed.
- Mathematically a cascade of first-order exponential delays can be modeled as a convolution of exponential delays giving an Erlang distribution; see Sterman [3, pp. 462-476] for more details.
- The parameter
initin the Advanced tab allows to select →InitializationOptions:
- FixedValue (default) will use the parameter
initialValueto determine the initial output y. - SteadyState will set the initial output y equal to the initial input u.
- Free there will be no initial equation and thus the solver is free to find an initial output using
initialValueas an initial guess.
- FixedValue (default) will use the parameter
See also
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Time | delayTime | 1 | Constant delay time (optional) |
| OutputType | initialValue | 0 | Initial Output |
| Structural Parameters | |||
| Integer | n | 3 | Order of the smooth |
| Boolean | hasConstantDelayTime | true | if true, the constant parameter value is used |
| Advanced | |||
| InitializationOptions | init | modelSettings.init | Provide InitializationOptions (Free, FixedValue, SteadyState) |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Connectors.RealInput | u (from SmoothSISO) | Input | |
| Interfaces.Connectors.RealInput | u_delayTime | Delay time input |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| RealOutput | y (from SmoothSISO) | ||
| ModelSettings | modelSettings |