custom linearization. For more information, see “Specify Linear System for Block
Linearization Using MATLAB Expression” on page 2-162 and “Specify D-Matrix
System for Block Linearization Using Function” on page 2-163.Block Linearization
To verify whether a block linearized as expected, check the block linearization equations.
By default the software displays the linearization in state-space format. In the Show
linearization as drop-down list, you can select a different display format.To diagnose the cause of an unexpected block linearization, such as a block that linearizes
to zero, consider:- Any corresponding diagnostic messages. These messages can highlight common
causes of incorrect linearizations and propose potential solutions. - The block operating point. For example, if the input to a saturation block is outside the
saturation limits of the block, the block linearizes to zero. - The block parameters. For example, if a block is configured to use nondouble inputs or
states and has no predefined exact linearization, it linearizes to zero.
Block Operating Point
If the block does not linearize as expected, check the operating point. The operating point
at which the block is linearized consists of input and state values. If the operating point
for the block is incorrect, check whether the overall model operating point is correct. For
more information, see “Check Operating Point” on page 4-6.If an input signal value in the block operating point is incorrect, investigate the
linearization of upstream blocks from that signal. For example, consider a Product block
with two inputs. The operating point of this block consists of the two input signal values.
If either input value is zero, the path from the other input to the output linearizes to zero.If you expect the Product block to contribute to the linearization result for the operating
point at which you linearized the model, check the linearization for the block that
generates the zero input signal. For complex models, the cause of the incorrect input
signal can be more than one block upstream.4 Troubleshooting Linearization Results