Imagine the robot reaching down into a machine. As J2 rotates forward (positive direction), the forearm naturally drops. To keep the tool orientation level or to reach a specific Z-height, J3 must rotate to compensate. This compensation is the heart of the J2 J3 interaction. If the controller commands a movement but the mechanical linkage or tuning is off, the robot will exhibit "bouncing" or oscillation at the elbow.
allow users to simulate or even modify this coupling sense (changing values from 1 to -1) to test how it affects the robot's motion envelope. Are you currently working on calibrating a specific robot model or trying to resolve a joint limit error related to this interaction? fanuc j2 j3 interaction
If you suspect issues with the interaction or need to verify it: Position Screen : On the Teach Pendant, you can view the J2/J3 Interaction Imagine the robot reaching down into a machine
No discussion of is complete without addressing singularities. While the "Wrist Singularity" (J4 and J6 alignment) is the most famous, the "Elbow Singularity" or "Alignment Singularity" involves J2 and J3. This compensation is the heart of the J2 J3 interaction
From a mechanical standpoint, the position of J3 drastically alters the Center of Gravity for the J2 axis. When J3 extends the arm fully outward (flattening the elbow), the torque load on the J2 motor increases significantly. Conversely, when J3 folds the arm inward, the lever arm shortens, reducing the torque burden on J2.
) must remain within a specific range to prevent the robot from colliding with itself. Mastering/Calibration : During a Single Axis Master
On the Fanuc Teach Pendant, the value for J3 often represents the angle including the interaction (the angle relative to the horizontal/base plane) rather than just the angle relative to the J2 arm. Software like ROS often requires developers to mathematically "de-couple" these values using formulas like J2' = J2 - J3 to get the actual independent joint states.