Force/Torque Sensors in Robot Wrists and Ankles

Knowing exactly how hard you're pushing on something turns out to matter as much as knowing where you are.

A 6-axis force/torque sensor measures force along three perpendicular axes and torque (rotation) around each of those same three axes, giving a complete picture of the mechanical load at whatever joint it's mounted on.

At the wrist

A wrist-mounted F/T sensor lets a robot arm feel how hard it's gripping or pushing against something, enabling compliant behaviors like inserting a peg into a hole by feel, or stopping the instant unexpected resistance is detected — both much harder to do with position control alone.

At the ankle

An ankle-mounted F/T sensor tells the balance controller exactly how much weight is on each foot and where the center of pressure sits underneath it, which is core information for walking, standing on uneven terrain, and recovering from a push.