From factory workshops to kitchens and living rooms, a few strands of tendon-like ropes are transforming robots from clunky machines into gentle companions that can interact with us.
At the 2025 World Robot Conference, a robot capable of smoothly performing delicate actions such as grasping and passing attracted many spectators. The secret of this robot lies in its use of rope drive technology, which allows it to exhibit unprecedented compliance and safety during human interaction.
“If traditional rigid arms construct the robot’s ‘skeletal structure,’ then rope-driven arms reshape its ‘meridians.’ This is how Tian Yingmei, the technical leader of the Jianghuai Center Rope Drive S1 project, explained it.
This bionic design allows robots to become not just cold machines, but assistants that can integrate into our daily lives.
The Paradigm Shift in Robot Drive Technology
While traditional robotic rigid drive systems are powerful, they lack flexibility. Similar to the coordination of human joints and tendons, rope drive technology introduces flexible ropes between motors and joints, effectively reducing impact forces by utilizing the vibrations of the ropes themselves, significantly lowering the end contact force.
This technology mimics the working principle of human tendons, moving the drive motor from the hand to the forearm or torso, transmitting force and motion through slender “tendon ropes.”The rope-driven S1 robot has a total of 46 degrees of freedom, and its 7 degrees of freedom rope-driven arm design enables it to achieve millimeter-level compliant precision operations.
CTO Zhu Haohua pointed out: “Rope drive is not a novel technology; it has been used in industry for decades, such as in elevators and cranes. Its principle is simple, but engineering implementation is extremely difficult.”
It is precisely this “simple principle, difficult to implement” characteristic that makes rope drive technology a watershed in the field of robotics.
How Rope Drive Technology Achieves “Gentle Hands””
The core advantage of rope drive technology lies in its inherent compliance. Unlike the direct metal link transmission of traditional rigid arms, rope-driven arms use ropes for transmission, allowing the softness and vibrations of the ropes to achieve a load release effect.
The co-founder of Stardust Intelligence explained their rope drive technology: “This technology mimics the way human muscles exert force, making the robot’s performance faster, more compliant, and safer.”
This characteristic makes robots safer during human-robot interactions, especially suitable for service scenarios such as homes, hotels, and retail stores.
In practical applications, this gentleness is reflected not only in force control but also in fine operational capabilities. The Jianghuai Center’s rope-driven S1 robot can perform tasks such as breakfast preparation, meal delivery, and cleaning, and is expected to become an intelligent housekeeper in future homes.
From Laboratory to Practical Application
In August 2025, the first humanoid robot in the country, acting as a “wedding officiant,” made its debut at the Civil Affairs Bureau in Nanshan District, Shenzhen. The S1 robot from Stardust Intelligence participated in the entire marriage registration process as a “witness of love,” assisting in welcoming guests, guiding them, and witnessing vows, showcasing the possibility of harmonious coexistence between robots and humans.
Stardust Intelligence founder Lai Jie pointed out: “The advantage of rope drive lies in ‘human living scenarios,’ such as homes and commercial services, because we set the single-arm rated load limit at 10 kilograms, which is based on human labor protection standards.”
This human-centered design approach makes rope-driven robots more suitable for entering human living spaces.
In addition to service scenarios, rope drive technology also shows great potential in the industrial field. In September 2025, Stardust Intelligence reached a cooperation agreement with Xian Gong Intelligent for a thousand-unit humanoid robot order, planning to deploy thousands of AI robots in phases over the next two years for industrial, manufacturing, warehousing, and logistics scenarios.
Technical Breakthroughs of Rope-Driven Dexterous Hands
The dexterous hand is a key component for robots to achieve fine operations. The DexHand021 five-finger dexterous hand launched by Stardust Intelligence has 19 degrees of freedom and 23 sensors, weighing only 1kg, yet capable of integrating 12 hollow cup motors, 19 joints, and a tendon drive system within a limited space.
The fingertips resemble the curves of human hands, with a surface layer of elastic silicone, and internally integrated with high-resolution miniature cameras. When the dexterous hand comes into contact with an object, the miniature camera captures the subtle changes in the elastic silicone layer, accurately calculating contact position and contact force, allowing it to grasp fragile objects like tofu without damage.
Zhu Haohua used a vivid analogy to explain the necessity of the five-finger dexterous hand: “You can try binding your ring finger and little finger together for a day, and you will find that many things become impossible or awkward; this is the irreplaceable truth of five fingers.”
This functional completeness allows the rope-driven dexterous hand to adapt to a wider variety of tasks.
Challenges and Breakthroughs Facing Rope Drive Technology
Every technology has its challenges. For rope drive technology, the main challenges focus on friction loss, pre-tension stability, and system integration complexity.
Friction loss can lead to accelerated wear of the tendon rope surface and increased risk of breakage; pre-tension stability issues concern whether the tendon rope can maintain constant tension to prevent slack or excessive tightness; while system integration complexity arises from the need to arrange dozens of tendon ropes within the dexterous hand, making path design highly complex.
Stardust Intelligence has addressed these challenges through material and algorithm innovations. “Our early research found that all elevators globally use rope drives, capable of pulling 3.6 tons of cabins, with safety verified over decades.”Lai Jie explained, “but we use the ‘pre-calibration real-time compensation’ algorithm to calculate the rope’s ‘force-deformation’ relationship in advance, allowing the motor to adjust the tension in real-time, ultimately controlling the error within plus or minus 0.03 millimeters.”
Future Applications: From Imagination to Reality
As rope drive technology matures, its application scenarios are continuously expanding. In the construction field, the first integrated rope-driven robot lightweight residential “Cloud Intelligent Manufacturing Factory” has been launched in Xiamen, where rope-driven robots perform tasks such as tying rebar and leveling concrete in the air, similar to a shuttle on a loom.
In home environments, rope-driven robots may become caring assistants for the elderly. Stardust Intelligence’s robots have already undergone application testing in nursing homes in Shenzhen, demonstrating potential in elderly care.
Zhu Haohua envisions the future: “The increase in intelligence leads to a fundamental shift in control methods, where today, control logic is more of a real-time dynamic adjustment driven by predictions, and under this control method, the rigidity requirements for the body are not as high.”
This shift in control paradigms is the stage for rope drive technology to showcase its capabilities.
At the 2025 World Artificial Intelligence Conference, staff wearing remote operation gloves operated the DexHand021Pro five-finger dexterous hand, which flexibly followed human hand movements in real-time. Such scenarios are transitioning from demonstrations to everyday occurrences.
From factory workshops to kitchens and living rooms, from industrial assembly lines to family life, rope drive technology is transforming robots from “steel giants” into “gentle assistants.” The “gentle hands” endowed by rope drive technology will be the key to their true integration into human society.
As Lai Jie, the founder of Stardust Intelligence, said: “AI robots entering thousands of households will still require 5 to 10 years of effort.”
And rope drive technology is accelerating the realization of this process.
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