Verify Pulley Configuration in Power Window System

The Simscape™ Driveline™ power window example contains a pulley network that uses tension and inertia and follows recommended belt-direction practices.

1. To open the model, in the MATLAB^® command window, enter

   openExample('sdl/PowerWindowSystemExample')

   

   The model contains the Mechanism subsystem, a masked pulley network subsystem. The DC Motor subsystem and a Worm Gear block work together to initiate motion in the pulley system. The system also contains an Inertia block.

2. To look inside the mask of the Mechanism subsystem, click the arrow in the lower-left corner of the block.

   

   The arrows show how the four Belt Pulley blocks rotate in response to the rotation of the Cable Drum block. If the drum rotates in the opposite direction, the pulley directions reverse, and the Lift Plate lowers. There are six pulley pairs:

   • Cable Drum and Pulley 1

   • Pulley 1 and Pulley 2

   • Pulley 2 and Pulley 3

   • Pulley 3 and Pulley 4

   • Pulley 4 and Cable Drum

   • Pulley 2 and Pulley 4

   You need at least five Rope blocks to build this system. The Lift Plate acts as a tensioner for the Pulley 2 and Pulley 4 pulley pair. The system contains four additional Rope blocks. In the figure, you can see how these blocks are implemented in the system.

   

   Each Rope block contains a spring and damper network separating the base port from the follower port.

3. Run the simulation and plot the results by clicking the Plot motor torque link in the model canvas. When the Cable Drum has a negative angular velocity, the Lift Plate raises the window. When the Cable Drum has a positive velocity, the Lift Plate lowers the window.

   

4. Open the Results Explorer by clicking the Explore simulation results link in the model canvas. On the Results Explorer toolbar, click the settings button and, for the Plot signals parameter, select Separate. Use Ctrl+click to open plots for:

   • Mechanism > Cable Drum > A > v

   • Pulley 1 > A > v

   • Pulley 1 > B > v

As expected, the velocity of the drum belt end at port A matches the velocity of the Pulley 1 belt end at port B and is the opposite of the velocity of the Pulley 1 belt end at port A.