What core technologies constitute a typical humanoid robot?

Hello! When it comes to humanoid robots, it's a hot topic. It's easy to understand if you imagine it as a "human," and its core technologies essentially correspond to different parts of the human body: the brain, senses, muscles/joints, and bones.

Let me break it down for you in plain language:

1. The Brain: Control System

This is the robot's "soul" and its most complex part. It determines how "smart" the robot is.

• Motion Control (Cerebellum and Motor Nerves): This is the most fundamental and also the most challenging aspect. How do you walk without falling? How can you reach out and accurately grab a cup from the table? Robots also need a system to precisely calculate how many degrees each joint should rotate, how much force to apply, and to maintain balance at all times. Behind this are extremely complex mathematical algorithms, such as "inverse kinematics" (which means knowing where the hand needs to go and then calculating how the shoulder, arm, and wrist should move) and "ZMP" (Zero Moment Point, a theory used to determine if a robot will fall while walking).
• Sensor Fusion (Brain Processing Sensory Information): Robots have many sensors (eyes, ears, skin), and they need to integrate all this disparate information to understand "where I am now," "what's in front of me," or "am I about to hit a wall?" For example, it needs to combine images seen by cameras with distances measured by LiDAR to build a 3D map of its surroundings.
• AI and Decision-Making (Brain Thinking): Once the environment is understood, what's next? That's where AI comes in. For example, if you tell it, "Get me a can of Coke," its brain needs to:
  1. Understand your words (speech recognition).
  2. Know what "Coke" looks like and that it's in the "refrigerator" (knowledge graph).
  3. Plan a path from its current location to the refrigerator (path planning).
  4. Plan a series of actions: open the refrigerator door -> identify the Coke -> reach out and grab it -> close the door -> walk back -> hand you the Coke (task planning). The integration of large models (like ChatGPT) has led to a qualitative leap in robots' "understanding" and "planning" capabilities.

2. Senses: Sensor System

These are the robot's "five senses," tools used to collect information from the outside world.

• Eyes (Visual Sensors): Mainly cameras. There are ordinary 2D cameras for recognizing colors and shapes (e.g., identifying faces, objects); more importantly, there are 3D cameras (or depth cameras) that can perceive the distance of objects, which is crucial for grasping things and avoiding obstacles.
• Ears (Voice/Auditory Sensors): These are microphone arrays, used to receive commands and identify the direction of sound sources.
• Sense of Balance (Inertial Measurement Unit, IMU): This is super important! It's like the vestibular system in human ears, sensing the robot's own posture (standing, lying down, or tilted) and acceleration of movement. Robots rely entirely on it to walk without falling. Your phone also has one; it's what works when you play games or watch videos in landscape mode.
• Touch/Force Sense (Torque Sensors): Distributed in the robot's joints, fingers, or feet. It allows the robot to perceive "force," for example, knowing how much force to apply when holding an egg so it doesn't crush it; or feeling whether the ground under its feet is soft or hard when walking. This is key to achieving delicate operations and safe interaction.
• Distance Sense (LiDAR / Ultrasound): Like a bat's echolocation, it precisely measures distances to surrounding objects by emitting and receiving reflections of laser or sound waves. That rotating "little hat" on top of many robot vacuums? That's LiDAR, used for mapping and navigation.

3. Muscles and Joints: Actuators

If the control system is the brain, then actuators are the "muscles" that turn the brain's ideas into actual movements.

• Servo Motors: These are not ordinary motors, but motor systems that can precisely control rotation angle, speed, and torque. Almost every joint in a robot has one of these "small muscles."
• Reducers (Gearboxes): Motors themselves spin very fast but have little strength (high speed, low torque), whereas robot joints require significant force (e.g., to support body weight). Reducers act like a "gearbox," converting the motor's high rotational speed into low speed and high torque output. This is one of the most core and precise components in a robot, especially "harmonic reducers," which are both expensive and critical.
• Hydraulic/Pneumatic: Some robots that pursue extreme explosive power and load capacity (like early Boston Dynamics' Atlas) use hydraulic systems. They are incredibly powerful but complex to control and carry the risk of oil leaks. There's a growing trend towards electric drives now.

4. Bones and Skin: Mechanical Structure and Materials

This is the robot's "physical body."

• Lightweight Structural Design: A robot's skeleton must be as light as possible, yet very sturdy. Because the heavier it is, the greater the burden on its "muscles" (actuators) and the more power it consumes. Therefore, advanced materials like aerospace aluminum and carbon fiber are commonly used.
• Biomimetic Design: Why make it humanoid? It's to enable it to adapt to environments designed for humans, such as opening doors, climbing stairs, and using tools. Its height, arm length, and leg length proportions are all carefully considered.
• Wiring Harness Management: A robot's entire body is filled with electrical and signal wires. Cleverly concealing these harnesses within the body and ensuring they don't wear out or break during repeated joint movements is a detail that severely tests engineering capabilities.

In summary, a humanoid robot is a complex integration of various cutting-edge technologies, including mechanics, electronics, computer science, materials science, and AI. Any single weakness will significantly compromise the robot's overall performance.