Developed Shield Tunnel Survey System 'WanWanSurvey™'

Okumura Corporation (Abeno-ku, Osaka; President and CEO: Takanori Okumura; hereinafter "Okumura") and Nishimatsu Construction Co., Ltd. (Minato-ku, Tokyo; President and CEO: Masakazu Hosokawa; hereinafter "Nishimatsu Construction") have jointly developed a survey system called "WanWanSurvey" that automates the work of installing prisms at known points in shield tunneling progress management surveys.

This system realizes unmanned operation of the prism installation work at known points in tunnel survey operations by replacing human labor with work performed by a quadruped robot. Furthermore, by combining it with the "Remote Survey System" utilizing a TS (Total Station) compatible with automatic surveying developed by Nishimatsu Construction, it enables complete unmanned operation of progress management surveys.

*1: A known point is a reference point for which information such as coordinates and height has already been provided.

Background

In the construction industry, efforts to improve productivity using ICT and other technologies are rapidly advancing against the backdrop of a declining labor population. In shield tunneling, challenges such as shortening work hours, reducing labor, and enhancing quality and safety management are being addressed, and initiatives toward the automation of tunnel surveys in progress management are required.

Tunnel surveys in shield construction must be performed after the excavation work is completed, and traditionally, workers entered the tunnel to perform the work manually. Because it is necessary to travel long distances within the shield tunnel, the work hours become long, leading to overtime for workers. In small-diameter shield tunnel construction, movement and surveying work in the narrow tunnel space impose a significant physical burden on workers. Even when using automatic surveying equipment (auto-tracking TS), human labor is required to move the prism to another known point. To solve these problems, the "WanWanSurvey" system, which enables automatic prism installation by a quadruped robot, has been developed.

In addition, patent applications are currently being filed jointly by Okumura and Nishimatsu Construction.

Figure 1: Overall image of "WanWanSurvey"

Overview of the "WanWanSurvey" System

This system automates the work of installing prisms at known points in tunnel surveys for shield construction progress management by utilizing a quadruped robot and a robot arm.

After the survey starts, the robot moves autonomously within the tunnel and automatically installs the prism at the designated known point. This realizes unmanned operation of tunnel movement and prism installation work.

Figure 2: System overview of "WanWanSurvey"

1. About the Quadruped Robot

The quadruped robot adopted in this system can move flexibly on scaffolding without depending on the tunnel's alignment or rail equipment*2. It is equipped with automatic start and return functions via remote control, eliminating the need for manual placement or retraction of the robot between survey tasks. By utilizing point cloud data acquired by the 3D-LiDAR sensor mounted on the robot's upper part and referring to pre-set coordinate point information, the movement to the known point is automatically controlled.

*2: Rail equipment refers to the rails, sleepers, and fixing devices used for the travel of trailing bogies and transport vehicles in shield tunnel construction.

Photo 1: Quadruped robot. Figure 3: Real-time analysis of 3D survey results.

2. About the Robot Arm

Upon arrival at the known point, the quadruped robot assumes a stable posture with a low center of gravity to prevent falling and ensure stability during prism installation, and deploys the robot arm. Then, based on images captured by the camera mounted on the tip of the robot arm, the AI optimizes the robot arm's position to install the prism vertically above the known point.

Photo 2: Robot arm.

3. Automatic Charging Station (Doghouse)

The quadruped robot automatically starts from the automatic charging station (contact charging system) installed on the rear bogie at the start of the survey (system startup) and automatically returns to charge after the survey is completed. If there is a step near the station that is difficult for the robot to overcome, a slope will be required.

Photo 3: Standby and charging status. Photo 4: Movement from charging station to known point.

Demonstration Tests Conducted

To confirm the effectiveness of this system, demonstration tests of the robot's walking ability and survey accuracy were conducted in a simulated tunnel using actual segments installed within Okumura Corporation's Technical Research Institute and at a shield tunnel construction site under construction by Okumura Corporation.

As a result, it was confirmed that autonomous movement is possible on scaffold boards (approximately 480mm wide) laid on the track gauge*3, and stable walking is possible even in sharp curve sections (curve radius of 35m). Furthermore, regarding prism installation accuracy, the difference between measured values for the distance between two points was confirmed to be approximately 2 mm.

*3: Track gauge refers to the distance between the two rails on which the trailing bogies run.

Photo 5: Inside the simulated tunnel.

Photo 6: Walking on scaffold boards (construction site).

Photo 7: Prism installation (construction site).

Photo 8: Known point recognition system UI.

Future Development

In the future, we will aim for further accuracy improvements and conduct more on-site demonstration tests to advance development toward practical application. Furthermore, by integrating with the "Remote Survey System," we will automate the entire process from prism installation to surveying known points and automatic aiming by the total station, promoting labor saving and efficiency in surveying work.

◆ Exhibiting at the 8th International Construction and Surveying Exhibition (CSPI-EXPO 2026)

We will jointly exhibit this technology at the booth of Nishimatsu Construction during the "8th International Construction and Surveying Exhibition (CSPI-EXPO 2026)" to be held at Makuhari Messe from June 17 (Wednesday) to 20 (Saturday), 2026.

[Contact Information for this Matter]

Okumura Corporation

Technology Division, Technical Research Institute, Planning and Management Group

TEL: 029-865-1521

FAX: 029-865-1522

E-mail: [email protected]

[Development Representative]

Okumura Corporation

Technology Division, Technical Research Institute, Civil Engineering Research Group

Ryutaro Matsumoto