In recent years, humanoid robots have become a hot topic in the technology field, seemingly making a giant leap from science fiction movies to the real world. In factory workshops, they collaborate precisely, boosting production efficiency; in home settings, they transform into considerate helpers, assisting children with learning, aiding the elderly in daily activities, and even managing household chores in an orderly fashion.
The reason why humanoid robots can be so "versatile" lies in their flexible and smooth "joint" movements, and the secret weapon behind this is the harmonic gear drive. As the core transmission component of robot joints, the harmonic gear drive is akin to the human joint cartilage, playing a crucial role in precise control and accurate transmission, ensuring each movement of the robot is smooth and fluent.
However, the current cost of harmonic gear drives, to some extent, limits the large-scale popularization and application of humanoid robots. Therefore, exploring effective cost control methods is not only the only way for enterprises to enhance competitiveness but also a key breakthrough to bring humanoid robots into thousands of households.
Core Component Procurement Costs
The core components of harmonic gear drives, such as the flexspline, circular spline, and wave generator, account for a significant proportion of the total cost. Taking the flexspline as an example, it is the most critical flexible component of the harmonic gear drive, bearing periodic alternating stresses, requiring extremely high fatigue strength, toughness, and machining accuracy of the material. Currently, high-quality flexspline materials mostly rely on imported special steel, which is costly.
Moreover, due to the complex production process of the flexspline, only a few manufacturers worldwide can stably supply high-quality flexsplines, leading to insufficient market competition and further driving up procurement prices.
Production Processing Costs
The production and processing of harmonic gear drives are highly costly, mainly due to their complex processing technology and high precision requirements. From the perspective of component processing, the inner teeth of the flexspline need high-precision electrical discharge machining (EDM), which has low processing speed and high material consumption. For instance, a medium-sized EDM machine's processing cost can reach hundreds of RMB per hour. To ensure tooth profile accuracy, multiple cuts and fine adjustments are often required, significantly increasing processing costs.
The external teeth of the circular spline also demand high-precision hobbing and grinding processes, with strict requirements for machine accuracy, stability, and operator skill levels. Any slight deviation can affect the transmission performance of the reducer. During assembly, the compact internal structure of the harmonic gear drive requires micro-level precision in component fitting. The assembly process must occur in a clean, constant temperature environment, conducted by experienced technicians using specialized jigs, incurring high labor and equipment maintenance costs.
Research and Testing Costs
Research and testing are also vital components of harmonic gear drive costs. To improve product performance and overcome technical bottlenecks, enterprises need to continuously invest substantial funds in R&D. On one hand, developing new tooth design and optimizing transmission structures requires specialized R&D teams and advanced design software and simulation analysis tools, with high labor and software procurement costs.
On the other hand, after product development, stringent testing procedures are necessary, including fatigue life testing, accuracy retention testing, and high/low-temperature adaptability testing. These tests are time-consuming – a complete fatigue life testing cycle can take several months. They also require specialized testing equipment, such as high-precision torque sensors and temperature control devices, leading to enormous equipment purchase and operational costs.
