Hardware

7-DOF Arm

A 7-DOF arm is a manipulator with seven independent joints, one more than the six required to place an end effector at an arbitrary pose, making it kinematically redundant. The extra degree of freedom, often arranged in a human-like shoulder-elbow-wrist (S-R-S) structure as in the KUKA iiwa and Franka Emika Panda, lets the elbow swivel through a null space to avoid obstacles, joint limits, and singularities while holding the hand fixed.

Why it matters for physical AI

Redundancy provides the workspace flexibility that cluttered human environments demand, and null-space motion gives whole-body and learned controllers room to optimize secondary objectives such as manipulability and collision clearance.