MATLAB SIMEVENTS RELEASE NOTES Betriebsanweisung PDF herunterladen (Seite 59)

Build a Hybrid Model

2-37

• Periodically, the Time-Based Entity Generator block creates an entity that conveys

the control signal value from the ABS controller to the braking system.

• The Set Attribute block attaches the control signal value to the entity. This data-

carrying entity is a data packet in the network.

• The N-Server block models the latency in the communication system by delaying each

data packet.

• The Get Attribute block models the reconstruction of data at the receiver. This block

connects to an Event to Timed Signal block that converts the data back to a time-

based signal. This time-based signal connects to the Brake System Dynamics block at

the top level of the model.

• Once the time-based control signal departs the subsystem and enters the Brake

System Dynamics block, the entity that carries the data through the delay

susbsystem is not needed. The Entity Sink block absorbs the entity.

This subsystem models communication from the controller to the braking system,

but does not model the feedback path from the braking system to the controller. The

model that you create is only a first step toward modeling a true distributed control

system, where all components of the system communicate over a common communication

bus. Next steps might involve modeling the communication in the feedback path and

replacing the N-Server block with a more realistic representation of the communication

link.

Add the Network Delay Subsystem Block

To add the Network Delay subsystem block to the original time-based model:

Open the abs_timebased model.

Select File > Save As. Save the model to your working folder as abs_hybrid.

Open the Simulink and SimEvents libraries. In the MATLAB Command Window

enter simulink and simevents.

From the Simulink Ports & Subsystems library, drag a Subsystem block into the

model window.

For the newly inserted Subsystem block, place the cursor in the text box that is

beneath the block. Type the new name, Network Delay.

Double-click the Delay Subsystem block. The procedure, “Add the Network Delay

Subsystem Contents” on page 2-38 shows you how to build the contents of the

subsystem.

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MATLAB SIMEVENTS RELEASE NOTES Betriebsanweisung Seite 59