User manual MATLAB CONTROL SYSTEM TOOLBOX 8

[. . . ] Control System ToolboxTM 8 User's Guide How to Contact The MathWorks Web Newsgroup www. mathworks. com/contact_TS. html Technical Support www. mathworks. com comp. soft-sys. matlab suggest@mathworks. com bugs@mathworks. com doc@mathworks. com service@mathworks. com info@mathworks. com Product enhancement suggestions Bug reports Documentation error reports Order status, license renewals, passcodes Sales, pricing, and general information 508-647-7000 (Phone) 508-647-7001 (Fax) The MathWorks, Inc. 3 Apple Hill Drive Natick, MA 01760-2098 For contact information about worldwide offices, see the MathWorks Web site. Control System ToolboxTM User's Guide © COPYRIGHT 2001­2010 by The MathWorks, Inc. The software described in this document is furnished under a license agreement. The software may be used or copied only under the terms of the license agreement. [. . . ] Both editors allow you to set default characteristics for specific instances of LTI Viewers and Graphical Tuning windows. If you open a new instance of either, each defaults to the characteristics specified in the Toolbox Preferences editor. 7-2 LTI Viewer Preferences Editor LTI Viewer Preferences Editor In this section. . . "Opening the LTI Viewer Preference Editor" on page 7-3 "Units Pane" on page 7-4 "Style Pane" on page 7-4 "Options Pane" on page 7-5 "Parameters Pane" on page 7-6 Opening the LTI Viewer Preference Editor Select LTI Viewer Preferences under the Edit menu of the LTI Viewer to open the LTI Viewer Preferences editor, which is a tool for customizing various LTI Viewer properties, including units, fonts, and various other viewer characteristics. This figure shows the editor open to its first pane. 7-3 7 Setting Tool Preferences Units Pane You can select the following on the Units pane: · Frequency -- Radians per second (rad/sec) or Hertz (Hz) · Magnitude -- Decibels (dB) or absolute value (abs) · Phase -- Degrees or radians For frequency axis, you can select logarithmic or linear scales. Style Pane Use the Style pane to toggle grid visibility and set font preferences and axes foreground colors for all plots in the LTI Viewer. This figure shows the Style pane. 7-4 LTI Viewer Preferences Editor You have the following choices: · Grid -- Activate grids for all plots in the LTI Viewer · Fonts -- Set the font size, weight (bold), and angle (italic) · Colors -- Specify the color vector to use for the axes foreground, which includes the X-Y axes, grid lines, and tick labels. Use a three-element vector to represent red, green, and blue (RGB) values. Vector element values can range from 0 to 1. · If you do not want to specify the RGB values numerically, press the Select button to open the Select Colors window. See "Select colors" on page 7-12 for more information. Options Pane The Options pane has selections for time responses and frequency responses. 7-5 7 Setting Tool Preferences The following choices are available: · Time Response: - Show settling time within xx%-- You can set the threshold of the settling time calculation to any percentage from 0 to 100%. Specify rise time from xx% to yy%-- The standard definition of rise time is the time it takes the signal to go from 10% to 90% of the final value. You can choose any percentages you like (from 0% to 100%), provided that the first value is smaller than the second. Only show magnitude above xx--Specify a lower limit for magnitude values in response plots so that you can focus on a region of interest. Unwrap phase--By default, the phase is unwrapped. If the phase is wrapped, all phase values are shifted such that their equivalent value displays in the range [-180°, 180°). · Frequency Response: - Parameters Pane Use the Parameters pane, shown below, to specify input vectors for time and frequency simulation. 7-6 LTI Viewer Preferences Editor The defaults are to generate time and frequency vectors for your plots automatically. You can, however, override the defaults as follows: · Time Vector: - Define stop time -- Specify the final time value for your simulation Define vector -- Specify the time vector manually using equal-sized time steps Define range -- Specify the bandwidth of your response. Whether it's in rad/sec or Hz depends on the selection you made in the Units pane. Define vector -- Specify the vector for your frequency values. Any real, positive, strictly monotonically increasing vector is valid. · Frequency Vector: 7-7 7 Setting Tool Preferences Graphical Tuning Window Preferences Editor In this section. . . "Opening the Graphical Tuning Window Preferences Editor" on page 7-8 "Units Pane" on page 7-9 "Time Delays Pane" on page 7-10 "Style Pane" on page 7-11 "Options Pane" on page 7-13 "Line Colors Pane" on page 7-14 Opening the Graphical Tuning Window Preferences Editor To open the SISO Tool Preferences editor, select SISO Tool Preferences from the Edit menu of the Graphical Tuning window. This window opens. 7-8 Graphical Tuning Window Preferences Editor Units Pane The Units pane has settings for the following units: · Frequency -- Radians per second (rad/sec) or Hertz (Hz) · Magnitude -- Decibels (dB) or absolute value (abs) · Phase -- Degrees or radians For frequency and magnitude axes, you can select logarithmic or linear scales. 7-9 7 Setting Tool Preferences Time Delays Pane In the Time Delays pane, specify the order for Padé approximations of delays in your system as either: · Actual Padé order · Bandwidth of accuracy (rad/s) -- The highest frequency at which the approximated response matches the actual system. The software computes and displays the corresponding Padé order. The following compensator design tools do not support systems with exact time delays. [. . . ] You can select: · Any individual plot (only one at a time) by clicking on a button · Any row or column by clicking on Y(*) or U(*) · All of the plots by clicking [all] Using these options, you can inspect individual I/O pairs, or look at particular I/O channels in detail. 12-24 Customizing the LTI Viewer Customizing the LTI Viewer In this section. . . "Overview of Customizing the LTI Viewer" on page 12-25 "LTI Viewer Preferences Editor" on page 12-25 Overview of Customizing the LTI Viewer The LTI Viewer has a tool preferences editor, which allows you to set default characteristics for specific instances of LTI Viewers. If you open a new instance of either, each defaults to the characteristics specified in the Toolbox Preferences editor. LTI Viewer Preferences Editor Select Viewer Preferences in the Edit menu of the LTI Viewer to open the LTI Viewer Preferences editor. This figure shows the editor open to its first pane. The LTI Viewer Preferences editor contains four panes: · Units--Convert between various units, including rad/sec and Hertz 12-25 12 LTI Viewer · Style--Customize grids, fonts, and colors · Characteristics--Specify response plot characteristics, such as settling time tolerance · Parameters--Set time and frequency ranges, stop times, and time step size If you want to customize the settings for all instances of LTI Viewers, see the Toolbox Preferences editor. 12-26 Index A Index addition of LTI models 2-15 scalar 2-16 adjoint. . [. . . ]