Ultra-Lightweight, Easy-to-Install Portable Collaborative Robot Accelerates Automation on Construction Sites

September 11, 2026
FANUC CORPORATION

 

The construction industry continues to face severe labor shortages and challenges in transferring skilled craftsmanship to the next generation. Against this background, the ultra-lightweight portable collaborative robot, the CRX-3iA, is attracting attention as a new solution for onsite automation.

The CRX-3iA was released at the International Robot Exhibition last year and is already being installed, particularly in the shipbuilding industry. In shipyards, operators carry the robot directly into large structures and easily use magnetic fixtures. Once welding begins, the robot performs the welding operation independently while the operator moves to another location to install an additional robot.

This approach allows a single operator to manage multiple robots simultaneously, delivering significant improvements in productivity and workforce efficiency.

Building on these successful operational results, we have expanded the concept to the construction industry and developed the CRX Structural Column Welding System. The system will be demonstrated live at the Japan International Welding Show, which will be held at Tokyo Big Sight starting on September 16.

Challenges in Construction Site Automation

• Despite growing demand for automation, the use of robots on construction sites has faced several challenges.
• Conventional robotic systems typically require safety fencing and additional peripheral equipment, such as external axes, to be brought to the onsite. As a result, these systems tend to be large, complex, and difficult to install in the field.
• In addition, automating the welding of structural steel columns on the first and second layers, where erection pieces are installed during steel-frame construction, has been particularly difficult. Consequently, many of these welding operations have continued to rely heavily on manual work.

Key Features of the Structural Column Welding System

Portable Collaborative Robot Enables Structural Column Welding

• The robot arm weighs just 11 kg. Despite being light enough to be carried with one hand, it delivers a wide maximum reach of 692 mm.
• Even for structural columns measuring 800 mm square, full circled welding can be achieved by positioning four robots at the four corners. Its lightweight and compact design allows easy transport and layout changes in narrow work areas, enabling flexible operation to suit on-site conditions.

Tool-Free Installation for Quick and Easy Setup

• Installation is simple. First, the magnetic base is attached to the column, and then the robot is mounted onto the base. The entire setup can be completed quickly without the use of any tools.
• In addition, the robot automatically detects its installation angle, eliminating the need for operators to manually input angles or perform complex setup procedures. The system can be applied not only to column welding but also to beam welding locations, making it suitable for a wide range of construction applications.

Start Welding Without Teaching

• The CRX-3iA automatically recognizes its installation orientation, eliminating the need to enter mounting angles, which is typically an essential setup parameter for collaborative robots. In addition, its laser sensor or touch-sensing functions automatically detect the welding position and compensate for joint variations by adjusting the weld path. As a result, operators simply install the robot and start the system to begin welding.
• The system also uses sensors to detect the position of erection pieces, which are unique to steel-frame construction sites, and accurately welds the areas between them. This enables the automation of a process that has traditionally relied on manual work, helping reduce workforce requirements while improving welding quality and consistency.

The Structural Steel Column Welding System will be exhibited at Japan International Welding Show 2026. We invite you to discover new possibilities for portable collaborative robots that are ultra-lightweight and easy to install.