How the Software Treats Loop Openings

金宝app^®Control Design™software linearizes models using a block-by-block approach. The software individually linearizes each block in your Simulink model and produces the linearization of the overall system by combining the individual block linearizations. For more information, seeExact Linearization Algorithm.

To obtain an open-loop transfer function from a model, you specify a loop opening. Loop openings affect only how the software recombines the individual linearized blocks. In other words, the software ignores loop openings when determining the input signal levels for each block, which affects how nonlinear blocks are linearized.

For example, in the following model, to compute the response frome₂toy₂without the effects of the outer loop, you open the outer loop by placing a loop opening analysis point aty₁.

Here,k₁,k₂,g₁, andg₂are nonlinear blocks.

The software linearizes each individual block at the specified operating point, creating the linearized blocksK₁,K₂,G₁, andG₂. At this stage, the software does not break the signal flow aty₁. Therefore, the block linearizations include the effects of the inner-loop and outer-loop feedback signals.

To compute the transfer function frome₂toy₂, the software enforces the loop opening aty₁, injects an input signal ate₂, and measures the output aty₂.

Here,K₁,K₂,G₁, andG₂are the linearized blocks.

The resulting linearized transfer function is (I+G₂K₂)^-1G₂K₂.

See Also

线性化|addOpening|getIOTransfer|getLoopTransfer|getSensitivity|getCompSensitivity

Related Topics

• Specify Portion of Model to Linearize
• Mark Signals of Interest for Batch Linearization
• Mark Signals of Interest for Control System Analysis and Design
• Compute Open-Loop Response