Edit Constraint(s) Dialog :: SISO Design Tool (Using the SISO Design Tool and the LTI Viewer)

Using the SISO Design Tool and the LTI Viewer

Edit Constraint(s) Dialog

The Edit Constraint(s) dialog allows you to exactly position constraint segments and to edit other properties of these constraints. The dialog has two main components:

Use the upper panel to specify the constraint you are editing.
Use the lower panel to edit the constraint parameters.

When used with the SISO Tool in the Control System Toolbox, the upper panel of the Edit Constraint(s) dialog resembles the image below. Editor refers to the particular editor within the SISO Tool that contains the constraint and Constraint refers to a particular constraint within that editor. To edit other constraints within the SISO Tool, change either the Editor or Constraint field within this dialog.

When used with Simulink Response Optimization, the upper panel of the Edit Constraint(s) dialog resembles the image below. Simulink Response Optimization constraints are always Time Bound constraints and the Constraint Type field of this dialog is not editable.

Constraint Parameters

The particular constraint parameters shown within the lower panel of the Edit Constraint(s) dialog depend on the type of constraint. The table below summarizes the various constraint parameters.

Constraint Parameter
Found in
Description

Select edge to edit
Simulink Response Optimization, SISO Tool Open-Loop Bode Editor, Prefilter Bode Editor, SISO Tool Open-Loop Nichols Editor, SISO Tool Root Locus Editor
When a constraint contains more than one segment, also known as an edge, you can use this menu to choose the edge you want to edit. Edges are numbered from left to right starting at 1.

Time
Simulink Response Optimization
Defines the time range of an edge within a constraint.

Magnitude
Simulink Response Optimization, SISO Tool Open-Loop Bode Editor, Prefilter Bode Editor
Defines beginning and ending amplitude of a constraint edge.

Weight
Simulink Response Optimization
Defines the weight of an edge within a constraint. The weight is a measure of the relative importance of this constraint edge when used in a response optimization. Weights can vary between 0 and 1 where 0 implies that the constraint edge is disabled and does not have to be satisfied and 1 implies that the constraint edge must be satisfied. The weight of a constraint edge is graphically represented by the thickness of the black constraint line. An invisible constraint edge represents a weight of 0 and a thick constraint edge represents a weight of 1.

Frequency
SISO Tool Open-Loop Bode Editor, Prefilter Bode Editor
Defines the frequency range of an edge within a constraint.

Slope (dB/decade)
SISO Tool Open-Loop Bode Editor, Prefilter Bode Editor
Defines the slope, in dB/decade, of a constraint edge. It is an alternative method of specifying the magnitude values. Entering a new Slope value changes any previously defined magnitude values.

Settling Time <
SISO Tool Root Locus Editor
Defines a constraint edge for a particular settling time.

Percent overshoot <
SISO Tool Root Locus Editor
Defines constraint edges for a particular percent overshoot.

Damping Ratio >
SISO Tool Root Locus Editor
Defines constraint edges for a particular damping ratio.

Natural Frequency
SISO Tool Root Locus Editor
Defines a constraint edge for a particular natural frequency. To specify the constraint, choose at least or at most from the menu, and then specify the natural frequency of interest.

Real
SISO Tool Root Locus Editor
Defines the beginning and end of the real component of a pole-zero region constraint.

Imaginary
SISO Tool Root Locus Editor
Defines beginning and end of the imaginary component of a pole-zero region constraint.

Phase Margin >
SISO Tool Open-Loop Nichols Editor
Defines a constraint edge for a minimum phase margin. The phase margin specified should be a number greater than 0.

Located at
SISO Tool Open-Loop Nichols Editor
Defines the center, in degrees, of the constraint edge defining the phase margin, gain margin, or closed-loop peak gain. The location must be -180 plus a multiple of 360 degrees. If you enter an invalid location point, the closest valid location is selected.

Gain Margin >
SISO Tool Open-Loop Nichols Editor
Defines a constraint edge for a particular gain margin.

Closed-Loop Peak Gain <
SISO Tool Open-Loop Nichols Editor
Defines a constraint edge for a particular closed-loop peak gain. The specified value can be positive or negative in dB. The constraint follows the curves of the Nichols plot grid, so it is recommended that you have the grid on when using this feature.

Open loop phase
SISO Tool Open-Loop Nichols Editor
Defines the beginning and end of the open loop phase component of a gain-phase constraint edge.

Open loop gain
SISO Tool Open-Loop Nichols Editor
Defines the beginning and end of the open loop gain component of a gain-phase constraint edge.

Constraint Parameter	Found in	Description
Select edge to edit	Simulink Response Optimization, SISO Tool Open-Loop Bode Editor, Prefilter Bode Editor, SISO Tool Open-Loop Nichols Editor, SISO Tool Root Locus Editor	When a constraint contains more than one segment, also known as an edge, you can use this menu to choose the edge you want to edit. Edges are numbered from left to right starting at 1.
Time	Simulink Response Optimization	Defines the time range of an edge within a constraint.
Magnitude	Simulink Response Optimization, SISO Tool Open-Loop Bode Editor, Prefilter Bode Editor	Defines beginning and ending amplitude of a constraint edge.
Weight	Simulink Response Optimization	Defines the weight of an edge within a constraint. The weight is a measure of the relative importance of this constraint edge when used in a response optimization. Weights can vary between 0 and 1 where 0 implies that the constraint edge is disabled and does not have to be satisfied and 1 implies that the constraint edge must be satisfied. The weight of a constraint edge is graphically represented by the thickness of the black constraint line. An invisible constraint edge represents a weight of 0 and a thick constraint edge represents a weight of 1.
Frequency	SISO Tool Open-Loop Bode Editor, Prefilter Bode Editor	Defines the frequency range of an edge within a constraint.
Slope (dB/decade)	SISO Tool Open-Loop Bode Editor, Prefilter Bode Editor	Defines the slope, in dB/decade, of a constraint edge. It is an alternative method of specifying the magnitude values. Entering a new Slope value changes any previously defined magnitude values.
Settling Time <	SISO Tool Root Locus Editor	Defines a constraint edge for a particular settling time.
Percent overshoot <	SISO Tool Root Locus Editor	Defines constraint edges for a particular percent overshoot.
Damping Ratio >	SISO Tool Root Locus Editor	Defines constraint edges for a particular damping ratio.
Natural Frequency	SISO Tool Root Locus Editor	Defines a constraint edge for a particular natural frequency. To specify the constraint, choose `at least` or `at most` from the menu, and then specify the natural frequency of interest.
Real	SISO Tool Root Locus Editor	Defines the beginning and end of the real component of a pole-zero region constraint.
Imaginary	SISO Tool Root Locus Editor	Defines beginning and end of the imaginary component of a pole-zero region constraint.
Phase Margin >	SISO Tool Open-Loop Nichols Editor	Defines a constraint edge for a minimum phase margin. The phase margin specified should be a number greater than 0.
Located at	SISO Tool Open-Loop Nichols Editor	Defines the center, in degrees, of the constraint edge defining the phase margin, gain margin, or closed-loop peak gain. The location must be -180 plus a multiple of 360 degrees. If you enter an invalid location point, the closest valid location is selected.
Gain Margin >	SISO Tool Open-Loop Nichols Editor	Defines a constraint edge for a particular gain margin.
Closed-Loop Peak Gain <	SISO Tool Open-Loop Nichols Editor	Defines a constraint edge for a particular closed-loop peak gain. The specified value can be positive or negative in dB. The constraint follows the curves of the Nichols plot grid, so it is recommended that you have the grid on when using this feature.
Open loop phase	SISO Tool Open-Loop Nichols Editor	Defines the beginning and end of the open loop phase component of a gain-phase constraint edge.
Open loop gain	SISO Tool Open-Loop Nichols Editor	Defines the beginning and end of the open loop gain component of a gain-phase constraint edge.

Editing Constraints Deleting Constraints