‌Articulated Arm Coordinate Measuring Machines‌ (also known as portable 3D measurement arms or articulated CMMs) are coordinate measurement systems based on rotating joints and arms. They determine the probe’s coordinates in the instrument frame by measuring rotation angles via angular encoders at each joint and performing coordinate transformations.

Typically comprising three joints – the ‌shoulder joint‌, ‌elbow joint‌, and ‌wrist joint‌ – these systems feature specific rotation axes:

• Shoulder joint: Includes ‌A-axis‌ and ‌B-axis‌ rotation
• Elbow joint: Includes ‌D-axis‌ rotation
• Wrist joint: Includes ‌E-axis‌ and ‌lower rotation axis‌

The probe is mounted on the final rotation axis and operates through manual manipulation. Common configurations include ‌5-axis‌, ‌6-axis‌, and ‌7-axis‌ structures (referring to degrees of freedom).