Getting Started

Plotting MIMO Model Responses

For MIMO models, time and frequency response functions produce an array of plots with one plot per I/O channel (or per output for initial and lsim). For example,

h = [tf(10,[1 2 10]) , tf(1,[1 1])]
step(h)

produces the following plot.

Figure 3-13: Step Responses for a MIMO Model

The simulation horizon is automatically determined based on the model dynamics. You can override this automatic mode by specifying a final time,

step(h,10) % Simulates from 0 to 10 seconds

or a vector of evenly spaced time samples.

t = 0:0.01:10   % Time samples spaced every 0.01 second
step(h,t)

Right-Click Menus

All the time and frequency response functions provide right-click menus that allow you to customize your plots. This picture shows the plots from Figure 3-13, Step Responses for a MIMO Model,, with the right-click menu open.

Figure 3-14: Using the Right-Click Menu in a Step Response Plot

The options you can select include:

• Systems -- Select or deselect any models that you included when you created the response plot.
• Characteristics -- Add information about the plot. The characteristics available change from plot to plot. For example, Bode plots have stability margins available, but step responses have rise time and steady-state values available.
• Axes Grouping -- Change the grouping of your plots. Available options are All, None, Inputs, and Outputs. You can group all the plots together, place each in a separate plot region (none), or group the inputs or outputs together.
• I/O Selector -- Open the I/O Selector Window.
  
  

Use this window to select/deselect which inputs and outputs to plot.

• Zoom -- Zoom in and out of plot regions.
• Grid -- Add grids to your plots.
• Properties -- Open the Property Editor, which you can use to customize various attributes of your plot. See Customization in the Control System Toolbox online documentation for a full description of the Property Editor.

Alternatively, you can open the Property Editor by double-clicking in an empty region of the response plot.

Time and Frequency Responses

Data Markers