Humanoid robots are a type of robot that imitate human appearance and certain behaviors, usually designed to have a shape similar to that of a human. They are applied in multiple fields such as service sector, healthcare, education, scientific research and industrial automation. With their human-like perception and interaction capabilities, limb structures and movement patterns, humanoid robots can quickly integrate into various environments designed for humans. In the future, they are expected to replace humans in simple repetitive labor and dangerous operations, and also assist humans in completing complex tasks.

Sensor systems constitute the fundamental enabler for humanoid robotic perception, transmitting acquired data to the central processing unit (CPU) to execute responsive actuation. Both internal proprioceptive sensing (critical for performance monitoring) and external exteroceptive modalities (tactile, visual, auditory) are mission-critical, directly determining the robot's operational envelope and application scope.

Humanoid robot sensors mainly used in:

Environmental perception

Vision sensor:

Vision sensors serve as critical perceptual interfaces for robotic environmental interaction, enabling functionalities including environmental awareness, navigation, object recognition, and facial identification. Primary vision sensor modalities encompass: Stereo Cameras, Depth Cameras, LiDAR and Infrared Sensors. These sensors can provide color, depth, and distance information to help robots better understand and adapt to their surroundings.

LiDAR:

LiDAR (Light Detection and Ranging) systems generate precise 3D point cloud maps by emitting laser pulses and calculating Time-of-Flight (ToF) of reflected signals. The sensor can accurately sense the distance between the robot and surrounding objects. This is very effective for navigation and path planning in complex environments, such as outdoor patrols and logistics handling, helping robots accurately avoid obstacles and plan safe paths.

Ultrasonic sensor:

Ultrasonic sensors utilize the echo ranging principle to measure distances through sound wave reflection, primarily deployed for short-range obstacle detection. These devices are particularly effective in confined-space robotics applications, enabling proximity awareness and collision prevention in geometrically complex environments.

Motion control

Joint position sensor:

Deployed at robotic articulations, provide real-time feedback on angular displacement and positional states, enabling precise limb motion control. Achieving a variety of complex movements, such as the accurate imitation of dance, martial arts movements, and high-precision assembly operations in industrial production.

Joint Angle Sensor: Monitor the robot's limb position and range of motion.

Force/Torque sensor:

The force/torque sensor is a core component for sensing and measuring force at the joints of humanoid robots. Deployed at the joints or end-effector of robots, they are able to accurately measure the forces and torques of an object in multiple directions and have vital influence in achieving fine manipulation, maintaining balance and avoiding damage. The common force/torque sensor including one-dimensional, three-dimensional and six-dimensional force sensors, of which the six-dimensional force sensor can simultaneously measure the force in three directions and the torque in three directions, providing a full range of force perception information.

Inertial Measurement Unit (IMU)

Inertial measurement unit (IMU) is an important component for humanoid robots to sense their own motion state. It is usually composed of sensors such as accelerometers, gyroscopes and magnetometers. IMU can measure the acceleration, angular velocity and direction of the robot in real time, and plays an important role in the robot's posture control, navigation and positioning.