For any given Cartesian or Task Space coordinates (x, y, z) of the end-effector, there are potentially multiple joint space configurations of the arm that can achieve that position. In these positions, the N9 shoulder and elbow angles will either move toward or away from the platform’s centerline.

When comparing between two possible joint space configurations with the same end-effector location, the configuration in which the N9 shoulder angle is closest to the centerline is called “shoulder center” on the IDE. The configuration in which the N9 shoulder angle is farthest from the centerline is called “shoulder out.”

Users can toggle between “shoulder center” and “shoulder out” configurations for a given position using the IK Solution field in the Location Dialog on the IDE, as depicted in the two images below. Notice how gripper remains in the same position, as indicated in the task space of each location, across two different joint space poses.

In a given end-effector location, the joint space configuration of the robot in which the N9 shoulder angle is closest to the centerline (i.e., shoulder and elbow joints are closest to 0 rad in joint space).

To minimize the risk of crashes, the IK Solution field defaults to shoulder center.

In a given end-effector location, the joint space configuration of the robot in which the N9 shoulder angle is farthest from the centerline.