On January 28, 2025, a technologically advanced humanoid robot made its debut at the backstage of the 2025 CCTV Spring Festival Gala. This is not only a perfect combination of technology and art, but also a vivid display of China's scientific research strength. When the robot danced on the stage and flipped its handkerchief,hief accurately, and complete each movement smoothly, it is the advanced servo drive system and high-precision reducer that support their stable operation. As a company focusing on servo drive and precision reduction technology, our core products have become the key to the precise control and stable operation of these robots.
Core Transmission Technology: Three High-Performance Reducers
To achieve stable, flexible, and efficient motion control in humanoid robots, reducers play a crucial role in the entire system. RV reducers, harmonic drives, and planetary reducers are applied to different robot joints, enhancing their load capacity, precision, and energy efficiency.
1. RV Reducer: The Core of High Load and High Precision
Working Principle:
- The RV reducer (Cycloidal Pinwheel Reducer) adopts a two-stage reduction structure: the first stage is a conventional planetary gear reduction, and the second stage is a cycloidal pinwheel reduction.
- It mainly consists of cycloidal wheels, a pin housing, an input shaft, and an output shaft. The input end drives the cycloidal wheels to rotate, and through pin gear transmission, a high reduction ratio is achieved.
Features:
✅ High Rigidity: The RV reducer uses cycloidal pinwheel transmission, making it stronger and more impact-resistant than traditional gear reducers.
✅ High Precision: Minimal backlash (less than 1 arcmin) meets the high-precision motion control requirements of robots.
✅ High Torque Density: Ideal for large robot joints (e.g., hip and knee joints) to withstand heavy loads.
Applications:
Widely used in industrial robots, robotic arms, and heavy-load joints, ensuring stability in complex robotic movements.
2. Harmonic Drive: The Key to Lightweight and High Reduction Ratios
Working Principle:
- A harmonic reducer consists of a wave generator, a flexible spline, and a circular spline.
- The wave generator is an elliptical metal wheel that deforms the flexible spline and engages it with the circular spline to achieve a high reduction ratio.
Features:
✅ Ultra-High Reduction Ratio: Compared to the RV reducer, a harmonic drive can easily reach a 1:50 to 1:160 reduction ratio.
✅ Lightweight Structure: Compact design and low weight, making it ideal for small robot joints (e.g., wrist joints and finger joints).
✅ High Precision & Low Backlash: Ensures accurate micro-movements in robots, such as handkerchief-spinning and handshaking.
Applications:
Primarily used in collaborative robots, service robots, and precision control equipment, such as the precise wrist joint control of robots on the Spring Festival Gala stage.
3. Planetary Reducer: A Versatile and Efficient Reduction Solution

Working Principle:
- A planetary reducer consists of a sun gear, planetary gears, and an internal ring gear. Multiple planetary gears rotate around the sun gear, transmitting power.
- The simultaneous engagement of multiple planetary gears ensures even force distribution and improved transmission efficiency.
Features:
✅ High Efficiency: With a transmission efficiency of over 95%, it minimizes energy loss, making it ideal for high-performance robot systems.
✅ Compact Structure & Wide Applicability: Suitable for medium and small robot joints and industrial automation equipment.
✅ High Load Capacity: Widely used in robotic mobility systems, such as leg-driven mechanisms and mobile platforms.
Applications:
Ideal for AGVs (Automated Guided Vehicles), humanoid robot leg drives, and other applications requiring efficient and stable power transmission.
As humanoid robotics technology advances, reducer design and manufacturing continue to evolve. RV reducers provide high-load support, harmonic drives enable ultra-precise motion control, and planetary reducers achieve the perfect balance between compactness and efficiency. These core technologies are driving robots toward higher precision, greater power, and lighter structures.
HKT-ROBOT, specializing in motion control and intelligent drive systems, is dedicated to developing high-performance AGV motors, servo systems, and reducers, delivering efficient and precise power solutions for the robotics industry. With continuous innovations in materials, structure, and manufacturing processes, HKT-ROBOT is paving the way for a smarter and more powerful future in robotics.
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