Recently, the research team led by Wang Shuang, a faculty member from the School of Precision Instrument and Optoelectronics Engineering at Tianjin University, completed the project "Key Technologies and Applications of Optoelectronic Fusion Sensing for Automatic Assembly of Shield Tunneling Segment Erector Machines," which was awarded the Second Prize of the Tianjin Science and Technology Progress Award.

In tunnel engineering, the assembly performance of shield machines is directly related to construction safety and tunnel quality. Addressing the practical needs and bottleneck problems in shield construction regarding segment posture analysis, precise segment positioning, and precise motion control of the erector machine, Tianjin University, Tianjin Qiushi Feibo Technology Co., Ltd., CCCC Tianhe Mechanical Equipment Manufacturing Co., Ltd., and CCCC ** Navigation Engineering Bureau Co., Ltd. jointly developed the key technology of optoelectronic fusion sensing for automatic assembly of shield tunneling segment erector machines.

Many complex situations arose during the project, and on-site debugging alone lasted four years. As early as nine years ago, Tianjin University and Tianjin Qiushi Feibo Technology Co., Ltd. began exchanges with the research team of CCCC Tianhe Mechanical Equipment Manufacturing Co., Ltd. and came into contact with the shield segment assembly project. Since the project was officially established in 2016, the research team members have consistently carried out industry-university-research cooperation, from model construction to workshop experiments and then to construction sites, debugging and testing while improving. Ultimately, they developed the most usable and practical technical method for automatic shield assembly.

It is not easy to go from a scientific research project to actual technological implementation and application that generates benefits. The team members initially spent more than a year resolving theoretical issues; the laboratory stage was not very difficult. Our initial goal was very clear: to achieve good automatic assembly. After comprehensively considering requirements such as detection accuracy, range, and environmental adaptability, we finally determined that optoelectronics was the most feasible solution.

However, in practical applications, they found that the problems to be solved far exceeded the models constructed in the laboratory. The engineering application stage was extremely difficult. It appears to be a three-dimensional plane, but in reality the erector machine has six degrees of freedom, and parameters must be adjusted and set for different segment sizes. Performing fine operations on very heavy and large equipment increases engineering difficulty and imposes very high requirements.

The on-site debugging process lasted as long as four years. System debugging had to consider both the time costs of the construction unit and the need to avoid collision risks during debugging, while the system scheme and algorithms also had to adapt to the complex shield construction environment. In the tunnel construction environment, controlling the assembly error of large-tonnage segments to within 3 millimeters is very challenging. To some extent, it can be said that the process of implementing the technology is no less difficult than the creative process from 0 to 1.

During the engineering debugging stage, for example, parameters verified in the debugging workshop showed large actual assembly discrepancies once viewed on site. Ultimately, the original method was revised, combined with erector machine status monitoring and feedback control technology, and an optical lever effect was added to improve assembly accuracy.

At present, the research team is still considering how to solve detection problems in other shield technology fields, such as abnormal main bearing fault detection, hoping to achieve earlier warning.

At present, the project technology can already assist and replace manual assembly methods. As a component of the shield machine erector, it assists in tunnel excavation engineering and improves the quality and efficiency of tunnel engineering construction. The project includes applications of technologies such as imaging, laser ranging, and optical fiber. The project has been granted 9 Chinese invention patents and 2 utility model patents. The project technology has been applied in more than ten national major engineering fields, including subways, railways, highways, municipal pipe networks, river-crossing tunnels, and hydropower, achieving significant economic and social benefits.