Purpose

Initialize the SISO Design Tool

Syntax

sisotool
sisotool(plant)
sisotool(plant,comp)
sisotool(views)
sisotools(views,plant,comp)
sisotool(views,plant,comp,options)

Description

When invoked without input arguments, sisotool initializes a SISO Design GUI for interactive compensator design. This GUI allows you to design a single-input/single-output (SISO) compensator using root locus and Bode diagram techniques.

This picture shows the SISO Design Tool.

sisotool(plant) opens the SISO Design Tool with plant imported. If your 
plant is any SISO LTI object (created with ss, tf, or zpk) that exists in the 
MATLAB workspace, sisotool(plant)

initializes a SISO Design Tool with the plant model P set to plant. The SISO Design Tool draws the root locus of the closed-lop poles and zeros. The Bode diagram plots the open-loop frequency response (both magnitude and phase) of the plant.

sisotool(plant,comp)

also initializes a SISO Design Tool for the plant model plant. In addition, the root locus compensator is initialized to comp, where comp is any SISO LTI object that exists in the MATLAB workspace.

By default, the SISO Design Tool:

Opens root locus and Bode diagrams.

Places the compensator in the forward path.

Assumes the prefilter, F, and the sensor, H, are unity gains. If you want to include F and H in the design model, open the Import Model window and select the models you want to use for each.

sisotool(views) or sisotool(views,plant,comp) specifies the initial configuration of the SISO Design Tool. The parameter views can be any of the following strings (or combination thereof):

'rlocus' -- Root Locus plot

'bode' -- Bode diagrams of the open-loop response

For example

        sisotool('bode')

opens a SISO Design Tool with only the Bode Diagrams on.

sisotool(plant,comp,options) allows you to override the default compensator location and feedback sign by using an extra input argument options with the following fields:

options.Location = 'forward' -- Compensator in the forward loop

options.Location = 'feedback' -- Compensator in the feedback loop

options.Sign = -1 -- Negative feedback

options.Sign = 1 -- Positive feedback

You can design compensators for one of the following two feedback loop configurations.

Figure 1-1: The SISO Design Tool Supports Two Feedback Structures.

In either configuration, F is a pre-filter, P is the plant model, H is the sensor dynamics, and K is the compensator to be designed. In terms of the GUI design procedure, once you specify them, F, P, and H are fixed in the feedback structure. The default structure is for the compensator to be in the forward path.