Control

Joint Position Control

Joint position control is the servo-level tracking of commanded joint positions, conventionally implemented as cascaded position, velocity, and current loops with PID controllers running at kilohertz rates on the motor drives. It is the stiffest and most widespread control interface on commercial arms, and many learned manipulation policies output joint position targets that these loops execute.

Why it matters for physical AI

Position control's stiffness gives repeatability but punishes unexpected contact, so the choice between position, velocity, and torque interfaces shapes both policy action spaces and contact safety.