Foot Force Sensor

A sensor mounted on a legged robot’s foot or ankle that measures the contact force between foot and ground.

A foot force sensor measures ground-contact force at a legged robot’s foot; common forms include a single-axis force or pressure sensor at a quadruped’s foot tip, a six-axis force sensor at a humanoid’s ankle, or a pressure array laid across the sole. It answers two questions: is this foot on the ground, and how large is the ground reaction force? The first answer feeds contact estimation and leg odometry (you need to know which foot is bearing weight to infer how the body is moving); the second lets you compute the center of pressure and zero-moment point for judging balance. The foot takes an impact every step, so the sensor wears out and its readings drift, which is why many quadruped products skip it and instead do sensorless force estimation from joint torque or motor current. On the Unitree Go2, for example, only the EDU version has foot force sensors.

ExampleOlder Unitree Go1-generation quadruped SDKs (unitree_legged_sdk) provide a footForce field in the low-level LowState message with one force reading per foot, which the control program can use to judge each foot’s touchdown moment.

Also called

Foot Contact Sensor

Related

Contact Estimation · Six-Axis Force/Torque Sensor · Ground Reaction Force (GRF) · Zero Moment Point · Leg Odometry · Sensorless Force Estimation

Sources

Unitree Go2 产品页（规格表：足端力传感器仅 EDU 版） (Chinese)
unitree_legged_sdk comm.h（LowState footForce 字段） (Chinese)

As of

2026-09