Revolute Joint for the Simple Pendulum

Fig.6. A Simple Pendulum Connected to Ground by a Revolute

Configuring the Revolute Joint Block.

The geometry of the Joint connection is shown in the figure preceding. The ground point at (3, 4, 5) and the CS1 at (3, 4, 5) are actually the same point in space, but have been separated in the figure for clarity. The revolute rotation axis is along the + z direction:

1. Open the Joints library in the block library.

2. Drag and drop a Revolute block into your model window.

3. Rotate the Revolute block so that you can connect the base (B) side of the Joint to the Ground block and the follower (F) side of the Joint to the Body block. Make the two connections.

4. Open the Revolute dialog box. In the Parameters area, on the Axes pane, configure the rotation axis to the World z -axis:

a. Enter [0 0 1] under Axis of Action [x y z].

b. Leave the Reference CS at WORLD.

c. Ignore the Advanced tab.

Note several important things:

· Under Connection parameters, the Current base is located at GND@Ground, which is the Grounded CS associated with the Ground block located at (3, 4, 5) in World.

· Under Connection parameters, the Current follower is located at CS1@Body, which is the CS1 on Body1 located at (3, 4, 5) in World.

· This Joint's directionality runs from Ground to Body along the + z -axis.

Close the Revolute dialog box.