Simulink® Parameter Estimation™

Adaptive Lookup Table (1D Stair-Fit) - Perform one-dimensional adaptive table lookup

Description

The Adaptive Lookup Table (1D Stair-Fit) block creates a one-dimensional adaptive lookup table by dynamically updating the underlying lookup table. The block uses the outputs, ydata, of your system to do the adaptations.

Each indexing parameter U may take a value within a set of adapting data points, which are called breakpoints. Two breakpoints in each dimension define a cell. The set of all breakpoints in one of the dimensions defines a grid. In the one-dimensional case, each cell has two breakpoints, and the cell is a line segment.

You can use the Adaptive Lookup Table (1D Stair Fit) block to model time-varying systems.

Data Type Support

Doubles only

Dialog Box

First input (row) breakpoint set

The vector of values containing possible block input values. The input vector must be monotonically increasing.

Make initial table an input

Selecting this check box forces the Adaptive Lookup Table (1D Stair-Fit) block to ignore the Table data (initial) parameter. Instead, a new port appears with Tin next to it. Use this port to input table data.

Table data (initial)

The initial table output values. This vector must be of size N-1, where N is the number of breakpoints.

Table numbering data

Number values assigned to cells. This vector must be the same size as the table data vector, and each value must be unique.

Adaptation method

Choose Sample mean or Sample mean (with forgetting). Sample mean averages all the values received within a cell. Sample mean with forgetting gives more weight to the new data. How much weight is determined by the Adaptation gain parameter. For more information, see Selecting an Adaptation Method.

Adaptation gain (0 to 1)

A number between 0 and 1 that regulates the weight given to new data during the adaptation. A 0 means short memory (last data becomes the table value), and 1 means long memory (average all data received in a cell).

Make adapted table an output

Selecting this check box creates an additional output port for the adapted table.

Add adaptation enable/disable/reset port

Add an input port that enables, disables, or resets the adaptive lookup table. 0 = disable; 1 = enable; 2 = reset to initial table data.

Add cell lock enable/disable port

A port that provides the means for updating only specified cells during a simulation run. 0 = unlock; 1 = lock current cell.

Action for out-of-range input

Ignore or Adapt by extrapolating beyond the extreme breakpoints.

Block Reference

Adaptive Lookup Table (2D Stair-Fit)