Closed-Loop Control

A control strategy in which a system continuously measures the current state, compares it to a desired reference, and adjusts its output to minimize the error. Contrasted with open-loop control, which acts without sensing outcomes. In assistive wearables, closed-loop control is what allows a guidance cue to update in real time as the user moves — for example, a ring-mounted camera senses where a target is relative to the finger, and tendon motors adjust fingertip deflection frame by frame until the user converges on the target.