Summary of Key Points
This article analyzes the rapid evolution of robot bodies over the past two years by examining their physical components—skeletons, joints, sensors, and electrical systems. It highlights the role of a mature supply chain and breakthroughs in key technologies in this advancement, as well as the challenges involved in mass production and future milestones. The article emphasizes that the crucial factor in transforming robots from being capable to being user-friendly is their ability to integrate various systems effectively. The next major milestone is the development of robots that can perform simple tasks with precise perception and control, such as catching a falling leaf.
Detailed Analysis
#### 1. Skeleton Materials: Light Enough for Acrobatics, Strong Enough to Resist Impact
The robot’s skeleton, akin to human bones, must balance being lightweight and durable:
- Material Evolution: Early robots used steel (e.g., WABOT-1 weighed 160 kg and would create holes upon landing); later, aluminum alloys were used (one-third the density of steel); now, magnesium and titanium alloys are being explored (even lighter than aluminum, especially for impact-prone areas like knees and ankles).
- Cost Considerations: Skeleton suppliers earn a profit based on manufacturing costs, which include the cost of materials and processing. While processing costs decrease with mass production, material prices remain stable.
- Appearance and Durability: Decorative parts are made of plastic or synthetic materials to reduce wear and provide a comfortable touch. Bionic skins with embedded sensors are still in the early stages of development due to technical challenges (instability and deformation).
#### 2. Joint Actuators: The Most Expensive and Complex “Muscles”
Joints represent the most expensive and technically demanding parts of a robot, similar to human muscles:
- Core Components:
- Reducers: Function as amplifiers of force—high-speed motors generate low torque, which reducers increase through gears. There are three types: planetary (small and inexpensive for hands), harmonic (high precision and high torque for shoulders and elbows), and RV (impact-resistant for hips, knees, and waist). The challenge is ensuring consistency and durability in mass production (e.g., no noise or performance degradation after 1000 hours of use).
- Motors: Frameless torque motors are commonly used, eliminating the need for external bearings. Key issues include heat dissipation (instant heat generation during acrobatics), size (smaller motors are more flexible), and stable performance (precise control of current and torque to prevent malfunctions).
- In-house vs. Purchased Components: Buying off-the-shelf components is faster but more expensive, with limited performance; in-house development allows for better integration with algorithms. Leading companies often develop their own components or collaborate with suppliers.
#### 3. Sensor Systems: How Robots “Perceive” the World
Sensors enable robots to understand their environment and maintain balance:
- IMUs (Inertial Measurement Units): Similar to the inner ear, they detect body orientation and rotation, adjusting joint torque in real-time to prevent falls.
- Vision Systems: Cameras and lidar are used for distance measurement (similar to autonomous vehicles). Robots only need short-range detection (10–20 meters); higher precision is required for picking up small objects, so the systems must be compact and impact-resistant. Tesla’s Optimus uses cameras with 5 million pixels, while earlier versions aimed for 15 million pixels.
- Touch Sensation: Currently limited due to technical challenges (materials and algorithms). Three-dimensional touch sensors are expected to become more common by 2026, but they are still not widely used in mass-produced robots.
#### 4. Electrical and Computing Systems: The “Brain and Cerebellum” of Robots
The robot’s control system consists of a “brain” for complex tasks and a “cerebellum” for real-time adjustments:
- Brain Chips: Specialized chips like NVIDIA’s Orin/Thor or Qualcomm’s Dragonwing handle complex calculations.
- Cerebellum Chips: MCUs (e.g., STM32 from STMicroelectronics) control movements in milliseconds; any delay can lead to accidents.
- Trends: Integrating these chips is trending towards smaller sizes and faster communication for better coordination (e.g., the brain predicting trajectories while the “cerebellum” executes actions).
- Energy and Connectivity: Batteries (e.g., from CATL) are designed for high density and capacity, and wiring systems (e.g., from Lixin Precision) mimic neural networks.
#### 5. Mass Production: The Gap Between Being Capable and Being User-Friendly
While existing components can be assembled into a robot, being capable does not guarantee usability:
- Assembly Challenges: System integration is critical—imbalances in weight can affect balance and energy consumption. Issues like loose screws or worn wires may arise after extended use, requiring continuous tuning.
- Mass Production Challenges: Consistency is essential; even 10 robots may perform slightly differently when executing the same commands. Aging components also needs to be managed through online calibration.
- Advances in the Supply Chain: The robotics supply chain overlaps significantly with that of smartphones and automobiles (over 80% of components are shared). Suppliers are now willing to customize products for the robotics industry.
#### Future Milestone: Catching a Falling Leaf
Robots can already perform acrobatics, but they still fall short of human capabilities. The next major breakthrough will be robots that can perform simple tasks with precise perception and control, such as catching a leaf. This advancement would bring them one step closer to becoming an integral part of our daily lives.
The evolution of robot bodies is the result of advancements in multiple areas, including materials, components, algorithms, and supply chains. Every detail—such as the precision of gear in reducers or the efficiency of motors—plays a crucial role in enabling robots to move from the laboratory to mass production.