China Debuts Intelligent Cutter-Changing Robot for Large-Diameter TBMs

Introduction

Tunnel boring machines (TBMs) are among the most critical pieces of equipment in large-scale infrastructure projects, and their cutting tools—disc cutters on the cutterhead—wear rapidly when boring through rock and soil. Replacing these cutters traditionally requires workers to enter the cutter chamber under compressed-air conditions, a procedure that is time-consuming, physically demanding, and carries significant safety risks. On June 25, 2026, China Railway 14th Bureau Group officially released the country's first heavy-duty intelligent cutter-changing robot in Xiamen. The robot was deployed on the "Xiamen-Kinmen" TBM, which is being used for the Huandao Road tunnel section of the Xiamen-Kinmen Bridge (Xiamen section) project. This marks the first application of a cutter-changing robot in a large-diameter TBM project in China and signals a shift toward unmanned cutter replacement in large-diameter tunnel construction.

The Challenge of Traditional Cutter Replacement

In TBM tunneling, disc cutters act like teeth that continuously cut through rock and soil. Due to abrasive wear, they require frequent replacement. Under conventional methods, a crew of three workers must enter the pressurized cutter chamber to perform the replacement, which takes more than four hours per cutter. The working environment inside the chamber is cramped, poorly lit, hot and humid, and the air quality is poor. Workers face not only physical difficulty in maneuvering but also risks such as instability of the tunnel face. These conditions make cutter replacement one of the most hazardous routine operations in TBM tunneling.

Key Features of the Intelligent Cutter-Changing Robot

The newly released robot is designed to operate within the harsh environment of the cutter chamber. It features 11 independently controlled joints, providing strong obstacle-avoidance capabilities and fine manipulation. With a load capacity of 500 kg and a flexible, telescopic configuration, it can cover the entire cutterhead of TBMs ranging from 10 to 18 meters in diameter, and it can grasp and precisely replace heavy disc cutters. The robot's hardware and software are fully domestically developed, with 100% Chinese-owned intellectual property. To date, 38 invention patents have been filed and 7 software copyrights registered.

Technical Highlights: Vision and Control

A critical enabler of the robot's performance is its high-precision 3D infrared machine vision system. This system allows the robot to quickly scan and identify the exact position and wear status of each cutter even in the dim, humid, and low-visibility conditions of the front chamber, with positioning accuracy within 1 mm. Based on cutter location data, a digital twin management and control system receives real-time information and automatically plans the optimal cutter-changing sequence and robotic arm motion path. As a result, the time to replace a single disc cutter is reduced to 25–40 minutes, an efficiency improvement of over 50% compared with manual replacement. The entire process requires no personnel entry into the chamber, enabling minimally manned or unmanned operation and significantly enhancing the intrinsic safety of TBM construction.

Industry Significance and Expert Perspectives

The development and deployment of this robot have attracted attention from senior industry figures. Qian Qihu, academician of the Chinese Academy of Engineering, noted that the intelligent cutter-changing robot has achieved results in safety, efficiency, and cost, exploring a new path for the autonomous, unmanned, and intelligent development of China's transportation engineering equipment, and laying a foundation for industrial application. Xiao Mingqing, also an academician of the Chinese Academy of Engineering, commented that intelligent cutter-changing technology has long been a research hotspot domestically and internationally. China Railway Construction Corporation spent six years developing this technology, and its successful application represents a leap from manned to unmanned cutter replacement, which is of great significance for improving the safety, efficiency, and intelligence level of TBM construction.

Deployment Status and Future Outlook

The intelligent cutter-changing robot has completed on-machine debugging on the 16-meter-class "Xiamen-Kinmen" TBM, and all operational parameters have passed acceptance. The TBM is scheduled to commence boring on the left line at the end of June 2026, at which point the robot will assist in the safe and efficient excavation of the Huandao Road tunnel section of the Xiamen-Kinmen Bridge project. While the current application is specific to this project, the technology demonstrates a broader trend toward automation and remote operation in harsh underground construction environments. As large-diameter TBM projects increase worldwide, solutions that reduce personnel exposure to hazardous conditions while maintaining or improving efficiency are likely to gain attention. However, the adoption of such robotic systems will depend on project-specific factors, including TBM design, cutter type, and site logistics, and the long-term reliability and cost-effectiveness of the technology will need to be validated through extended operational data.

Sources and References

• China Industry News Network (CINN)

Frequently Asked Questions

What is the main advantage of the intelligent cutter-changing robot?

The primary advantage is that it eliminates the need for workers to enter the pressurized cutter chamber, significantly reducing safety risks associated with traditional manual replacement. It also reduces cutter replacement time to 25–40 minutes per cutter, improving efficiency by over 50%.

How does the robot ensure precise cutter replacement in dark and humid conditions?

The robot uses a 3D infrared machine vision system that can scan and identify cutter positions with 1 mm accuracy, even in low-visibility environments. A digital twin system then plans the optimal replacement sequence and arm path.

Can this robot be used on any TBM?

The robot is designed to cover cutterheads of TBMs with diameters from 10 to 18 meters. However, compatibility with specific TBM models and cutter types would need to be assessed on a case-by-case basis.

What is the current deployment status of the robot?

The robot has been installed and debugged on the 16-meter-class "Xiamen-Kinmen" TBM, and all operational parameters have passed acceptance. It is expected to support the TBM's boring of the left line starting at the end of June 2026.