Connecting Robot Parts Using Joints (Robotics Module)

A joint is the connection point where two robot parts make contact. Joints connect robot parts and constraint movement between the parts. Add joints between robot parts to build an integrated robot model. If you do not add joints between robot parts, the robot model that you save is broken and contains fragments.

You can view the connection of robot parts by setting the root of the robot model. In the Robot Simulation Model Builder, right-click a component in the Parts Hierarchy tree and select Set Root from the shortcut menu. The Parts Hierarchy displays all the robot parts that connect to this root component. The robot parts that do not connect to the root component display separately.

You can drag one robot component onto another component in the Parts List or Parts Hierarchy to add a joint between the two components.

You can set the joint type to configure different behaviors of movement. Select a joint in the Parts Hierarchy, right-click, and select Joint Type from the shortcut menu. Select one of the following types of joints:

• Fixed—Fixed joints maintain a fixed relative position and orientation between two bodies.
• Hinge (Revolute)—Hinge joints allow bodies to rotate around the axis of the joint.
• Slider (Prismatic)—Slider joints allow two bodies to move along an axis, but this kind of joint constrains the motion of a rigid body point along a line.
• Ball—Ball joints allow rotational movement between two bodies.
• Piston—Piston joints are similar to slider joints except that rotation around the translation axis is possible. The Robotics Module provides one type of piston joints, the spring joint, which returns to the original length when the joint is free of external forces. To add a spring joint to a robot model, select a joint in the Parts Hierarchy, right-click the joint, and select Joint Type»Piston»Spring from the shortcut menu.

Refer to the Springed Starter Kit.lvproj in the labview\examples\robotics\Simulator\Springed Starter Kit directory for an example of using the spring joint in a simulation application.