In 2023, DeepX, Inc., in collaboration with Oriental Shiraishi Corporation, developed an automatic driving system for construction machinery, specifically for ‘caisson excavators’ used in pneumatic caisson construction. Through demonstrative experiments, it was confirmed that multiple caisson excavators can be automated simultaneously and that this system meets the performance requirements necessary for on-site implementation.

 

■The significance of autonomous construction machinery in the construction industry
In the construction industry in Japan, compared to other industries, the aging rate is high, and the shortage of workers is a significant issue now and for the future. In recent years, there has been a strong push to alleviate the labor shortage in the construction industry by promoting labor-saving and automation measures. Within this context, the autonomous operation of construction machinery is expected to contribute to labor-saving and safety improvements, potentially alleviating and resolving significant challenges in this industry.

■Pneumatic caisson construction method
The pneumatic caisson construction method is widely used for bridge and building foundations, as well as sewer pump stations, underground adjustment tanks, shafts for shield tunnels, and main structures for subway and road tunnels. In this method, a reinforced concrete body (structure) is built on the ground, a workspace is set up at the bottom of the structure, and caisson excavators and earth buckets are installed. The process involves repeated excavation, soil removal, and sinking of the structure to advance vertically.

■Features of the automated construction machinery system developed and demonstrated
The autonomous operation system for the caisson excavators that was developed and demonstrated this time can automate the operation of the caisson excavators for excavation and transport of the excavated soil. Here are the five main features of this system.

・Real-time visualization system in digital-twin
In real-time, this system perceives the position and posture of the two caisson excavators, as well as the shape and height of the ground and can visualize them in three dimensions in a digital twin format. It can also automatically calculate one of the most important indicator, the opening ratio, that shows the unique and critical work situation in pneumatic caisson construction. As a result, on-site workers and supervisors can immediately get an overview of the current situation at any time, improving work efficiency and management efficiency.

 

・Collision prevention
This system has a feature that prevents collision between the caisson excavators. Specifically, if the two caisson excavators get too close, an alert will be issued on the screen, and if they get even closer, a warning will be issued and the operation will stop. This can prevent collisions between machinery not only during the automatic operation of multiple machines, but also when automatic and manual operations are mixed, improving the efficiency and safety of the entire operation.

 

・UI that makes it easy to specify work details
Users can initiate the automated operation simply by specifying the excavation area (where to dig) and soil removal area (where to transport the excavated soil) for each excavator on the GUI of this system, which visualizes the terrain and construction machinery in real time, and then clicking the start button. After starting the automatic operation, the system 1) automatically calculates the trajectory for moving the machinery, considering the shape of the ground, 2) the machinery moves automatically according to the calculated trajectory, and 3) the system can automatically carry out a series of operations such as excavation and soil removal in the specified areas.

 

・Simultaneous automatic operation of multiple machines
After the start of automatic operation, users basically only need to monitor the behavior of the machinery, so it is possible to operate multiple machines by one person, which is expected to have labor-saving effects. Also, it is possible to have continuous automatic operation during times when work is usually not done (for example, at night), which may potentially shorten the overall construction period.

・Stable automatic operation and seamless manual operation under conditions not suitable for automatic operation
In addition to a real-time environmental perception mechanism, this system allows for excavation operations that take into account the shape and hardness of the terrain. Therefore, it is a robust system that can cope with changes in the environment within a certain range, enabling stable automatic operation even at construction sites with many variations and fluctuations in conditions. In case of encountering irregular situations that cannot be dealt with above, it is assumed that the system will switch to manual operation, improve the situation by hand, and then switch back to automatic operation. To accommodate such operations, this system can easily switch from automatic operation to manual operation and vice versa.

Furthermore, Mr. Negishi from the Technical Department of Oriental Shiraishi, a user of the construction machinery automatic driving system developed this time, has given us the evaluation, “The system’s user interface is easy to see, and automatic operation can be executed with intuitive and simple operations. Even a single operator can keep multiple construction machines moving automatically without stopping, which is very convenient. In the future, we would like to challenge ourselves to expand the range of work we can handle while promoting the introduction to the site, and to move more construction machines at the same time“.

■Future outlook
We plan to introduce the construction machinery automatic driving system developed this time into the field within this fiscal year and start its actual operation. We will continue to forge ahead in pioneering the practical application of autonomous operation of construction machinery.

■About Oriental Shiraishi Corporation
Oriental Shiraishi Corporation engages in a wide variety of social infrastructure construction projects including bridges, highways, railroads, and lifeline facilities. Vast natural landscapes and future-oriented cities are the stages in which they utilize their state-of-the-art engineering capabilities and technologies. The technologies they specialize in include prestressed concrete products, construction, pneumatic caissons, structure retrofits and revamps. Their social infrastructure construction projects enhance people’s lives and ensure high safety standards through a variety of innovative technologies developed with the corporation’s extensive construction experience and R&D efforts. Oriental Shiraishi Corporation is continuously striving to improve the urban environment, develop new infrastructure, repair and reinforce existing infrastructure, and provide disaster countermeasures against natural disasters. Based on their management philosophy, ”Leveraging state-of-the-art engineering capabilities and technologies to contribute to society”, the company will continue to make steady progress.