Aerospace Blockset

Modeling with the Aerospace Blockset

If you have never used Simulink before, take some time to get acquainted with its features.

Begin by learning the two basic stages in model construction, discussed in the following sections:

• Model Definition
• Model Simulation

Model Definition

Simulink is a software package for modeling, simulating, and analyzing dynamic systems. Try building a simple model that drives an actuator with a sine wave and displays the actuator's position superimposed on the sine wave.

Note    If you prefer to open the complete model shown below instead of building it, type aeroblktutorial at the MATLAB command line.

Following are the procedures for defining a model on Windows and UNIX platforms.

• Defining a Model on Windows Platforms
• Defining a Model on UNIX Platforms

Defining a Model on Windows Platforms

1. Start Simulink.

1. Click the button in the MATLAB toolbar or enter simulink in the MATLAB Command Window. The Library Browser appears.
   
   

2. Open a new model.

1. Select New -> Model from the File menu in the Library Browser. A new model window appears on your screen.

   Alternate methods for creating a new model are by selecting New from the File menu in the Simulink model or by using the key sequence Ctrl+N.

3. Add a Sine Wave block to the model.
1. Click Sources in the Library Browser to view the blocks in the Simulink Sources library.
2. Drag the Sine Wave block from the Sources library into the new model window.
4. Add a Second Order Linear Actuator block to the model.
1. Click the  symbol next to Aerospace Blockset in the Library Browser to expand the hierarchical list of the aerospace blocks.
2. In the expanded list, click Actuators to view the blocks in the Actuator library.
3. Drag the Second Order Linear Actuator block into the model window.
5. Add a Mux block to the model.
1. Click Signal Routing in the Library Browser to view the blocks in the Simulink Signals & Systems library.
2. Drag the Mux block from the Signal Routing library into the model window.
6. Add a Scope block to the model.
1. Click Sinks in the Library Browser to view the blocks in the Simulink Sinks library.
2. Drag the Scope block from the Sinks library into the model window.
7. Resize the Mux block in the model.
1. Click the Mux block to select the block.
2. Hold down the mouse button and drag a corner of the Mux block to change the size of the block.
8. Connect the blocks.
1. Position the pointer near the output port of the Sine Wave block. Hold down the mouse button and drag the line that appears until it touches the input port of the Second Order Linear Actuator block. Release the mouse button.
2. Using the same technique, connect the output of the Second Order Linear Actuator block to the second input port of the Mux block.
3. Using the same technique, connect the output of the Mux block to the input port of the Scope block.
4. Position the pointer near the first input port of the Mux block. Hold down the mouse button and drag the line that appears over the line from the output port of the Sine Wave block until double crosshairs appear. Release the mouse button. The lines are connected when a knot is present at their intersection.
9. Set the block parameters.
1. Double-click the Sine Wave block. The dialog box that appears allows you to set the block's parameters. Parameters are defining values that tell the block how to operate.

• For this example, configure the block to generate a 10 rad/sec sine wave by entering 10 for the Frequency parameter. The sinusoid has the default amplitude of 1 and phase of 0 specified by the Amplitude and Phase offset parameters.

  

2. Click OK.
3. Double-click the Second Order Linear Actuator block.

• For this example, the actuator has the default natural frequency of 150 rad/sec, a damping ratio of 0.7, and an initial condition of 0 radians specified by the Natural frequency, Damping ratio, and Initial condition parameters.

  

4. Click OK.

You can now move on to the model simulation phase. See Model Simulation.

Defining a Model on UNIX Platforms

1. Start Simulink.

1. Enter simulink in the MATLAB Command Window. The Simulink Library window appears.
   
   

2. Open a new model.

1. Select New -> Model from the File menu in the Simulink Library window. A new model window appears on your screen.

   Alternate methods for creating a new model are by selecting New from the File menu in the Simulink model or by using the key sequence Ctrl+N.

3. Add a Sine Wave block to the model.
1. Double-click Sources in the Simulink Library window to view the blocks in the Simulink Sources library.
2. Drag the Sine Wave block from the Sources library into the new model window.
4. Add a Second Order Linear Actuator block to the model.
1. Double-click Blocksets & Toolboxes in the Simulink Library window. This opens the Blocksets and Toolboxes Library window.
2. Double-click Aerospace Blockset in the Blocksets and Toolboxes Library window. This opens the Aerospace Blockset block libraries.
3. In the Aerospace Blockset block libraries, click Actuators to view the blocks in the Actuator library.
4. Drag the Second Order Linear Actuator block into the model window.
5. Add a Mux block to the model.
1. Double-click Signal Routing in the Simulink Library to view the Signal Routing blocks.
2. Drag the Mux block from the Signal Routing library into the model window.
6. Add a Scope block to the model.
1. Double-click Sinks in the Simulink Library window to view the blocks in the Simulink Sinks library.
2. Drag the Scope block from the Sinks library into the model window.
7. Resize the Mux block in the model.
1. Click the Mux block to select the block.
2. Hold down the mouse button and drag a corner of the Mux block to change the size of the block.
8. Connect the blocks.
1. Position the pointer near the output port of the Sine Wave block. Hold down the mouse button and drag the line that appears until it touches the input port of the Second Order Linear Actuator block. Release the mouse button.
2. Using the same technique, connect the output of the Second Order Linear Actuator block to the second input port of the Mux block.
3. Using the same technique, connect the output of the Mux block to the input port of the Scope block.
4. Position the pointer near the first input port of the Mux block. Hold down the mouse button and drag the line that appears over the line from the output port of the Sine Wave block until double crosshairs appear. Release the mouse button. The lines are connected when a knot is present at their intersection.
9. Set the block parameters.
1. Double-click the Sine Wave block. The dialog box that appears allows you to set the block's parameters. Parameters are defining values that tell the block how to operate.

• For this example, configure the block to generate a 10 rad/sec sine wave by entering 10 for the Frequency parameter. The sinusoid has the default amplitude of 1 and phase of 0 specified by the Amplitude and Phase offset parameters.

  

2. Click OK.
3. Double-click the Second Order Linear Actuator block.

• For this example, the actuator has the default natural frequency of 150 rad/sec, a damping ratio of 0.7, and an initial condition of 0 radians specified by the Natural frequency, Damping ratio, and Initial condition parameters.

  

4. Click OK.

You can now move on to the model simulation phase. See Model Simulation.

Opening the Aerospace Blockset on UNIX Platforms

Model Simulation