Joint couplers allow the motion of a revolute, cylindrical, or translational joint to be coupled to the motion of another revolute, cylindrical or translational joint. The two coupled joints may be of the same or different types. For example, a revolute joint may be coupled to a translational joint. The coupled motion may also be of the same or different type. For example, the rotary motion of a revolute joint may be coupled to the rotary motion of a cylindrical joint, or the translational motion of a translational joint may be coupled to the rotary motion of a cylindrical joint.
A coupler takes two values, one for the motion of each joint, and from these derives a ratio that relates the motion of one joint to the motion of another joint. For example, if a revolute joint is being coupled with a translational joint, 90 degrees could be specified for the revolute joint, and 100 mm for the translational joint. This means that for every 90 degrees the revolute joint rotates, the translational joint moves 100 mm, or 1 degree of rotation results in 0.9 mm of translation (90/100).
A coupler does not differentiate between a driver joint and a driven joint. Either joint in the couple may at one point in time be driving the other joint. A potential for locking does exist if both joints in a coupler are driven by motion generators. The coupler may conflict with the motion generator.
A single joint may be coupled to more than one joint. Again, the potential for locking does exist if the multiple couples conflict with each other.
A coupler removes one additional degree of freedom from the motion model.
Joint couplers allow the motion of a revolute, cylindrical, or translational joint to be coupled to the motion of another revolute, cylindrical or translational joint.
To create a joint coupler:
Display the Edit Coupler dialog box using one of the following methods:
From the Motion menu, select Coupler.
Right-click the Couplers branch in the Browser, and then select Add Coupler.
Select one or two revolute, cylindrical, or translational joints in the Browser, and then select Add Coupler.
In the first and second text boxes, select a revolute, translational, or cylindrical joint from the Browser.
If the selected joint is a revolute joint, select Rotates.
If the joint is a translational joint, the select Translates.
If the joint is a cylindrical joint, select either Rotates or Translates, and then enter the degree of freedom of the joint to couple.
Specify the ratio between the two coupled joints. For example to couple two joints with a ratio of 2:1, enter 2 in the first box and 1 in the second box. To reverse the direction of one joint, enter a minus sign (-) in front of the number.
Select Apply to create the coupler.