Stanford School of Engineering & Doerr School of Sustainability
ENGINEERING Civil & Environmental Engineering
Center for Integrated Facility Engineering

Report "Scaled Robotics"

Introduction to the robot and the construction project

Scaled Robotics (Fig.1, Fig.3.), offers the inspection capability to automatically compare the built reality to a project’s BIM (Building Information Model) to help detect differences between reality and the plan. The Water Culture House (Fig.2.) is a public aquatic facility located in the harbor of Copenhagen, Denmark. The Water Culture House design includes thousands of plumbing, electrical, and ventilation elements, many of which have close-fitting tolerances between each other. The general contractor for the Water Culture House project, MT Højgaard, was interested in using Scaled Robotics AI inspection tools to be able to verify that the many close-fitting plumbing, electrical, and ventilation elements are all installed according to the BIM plan.

Fig.1. Scaled Robotics
Fig.1. Scaled Robotics
Fig.2. The Water Culture House
Fig.2. The Water Culture House
Fig.3. Web interface that shows the states of BIM elements
Fig.3. Web interface that shows the states of BIM elements

POP analysis

  • Product: MT Højgaard could manually verify the work by either manual spot checks or using laser scanners to collect data for comparison with BIM. Each of these manual approaches is cost and time prohibitive to validate the work regularly, leaving the project operating on low-resolution information. The robot uses a BLK2GO (handheld scanner) for inspections, and all data collected will be analyzed and visualized on a web interface (Fig.6.).
  • Organization: For the manual process, there are three organizations involved: the general contractor, subcontractors performing the installation work, and a third-party consultant who does quality control and verification of the installed elements on behalf of the general contractor. Scaled Robotics’ involvement replaces the independent quality consultant required for manual processes.
  • Process: The advantage of the Scaled Robotics process over the manual method is the rapid detection of needed rework across the entire construction site, which means that up to one rework cycle may be required. In contrast, it is difficult to inspect all installations at once using the manual process. In practice, incremental and piece-meal inspection may require multiple cycles of identifying and resolving rework, which may lead to the increasing of costs. 

Based on the POP analysis, the students conducted the robot was feasible for the selected project.

 

SQSC analysis

  • Safety: The BLK2GO scanner has a range of 25 meters, which enable the worker to inspect overhead installations without needing to climb ladders and risk falling from heights.
  • Quality: The largest benefit in terms of quality is the percentage of elements inspected. While manual inspections typically only check a few element installations at a time, Scaled Robotics can inspect all elements that are installed at once. Another benefit is that the robot can achieve higher accuracy. The BLK2GO has an accuracy indoors of 10 mm whereas manual inspection has an accuracy between the range of 1-100 mm depending on the skill of the worker and the tools which they use. 
  • Schedule: Scaled Robotics is able to quickly catch differences between the BIM and built reality which saves potentially months by reducing the amount of rework due to failure to catch errors at an early stage. Under the presented scenario, we estimated a savings of 800-1000 hours using the Scaled Robotics.
  • Cost: While the capital and subscription cost of using the robot is four times that of the manual, it helps reduce follow-up costs by 72% by reducing rework cycles and inspection work. Therefore, the total cost of using a robot is 23% higher than the cost of manual work.

 

Conclusion

During the analysis, we identified a couple of potential challenges when using Scaled Robotics for inspection tasks. One was the difficulty of verifying partial installations with Scaled Robotics. The other was that Scaled Robotics was so demanding that the inspection accuracy was even higher than the inspection tolerance required by the project so that not all out-of-tolerance elements detected by the robot needed to be reworked.  However, within the platform, there are tools that allow prioritization of work to help address these issues to some extent.

Overall, Scaled Robotics was the preferred installation inspection method over a manual inspection alternative, as MT Højgaard valued providing high-quality data products which help the project stay on schedule. Due to the priority on quality and schedule, the GC was willing to pay 23% more to meet those needs. In addition, Scaled Robotics could reduce the rework rate, and this advantage could be better reflected in complex and large-scale projects.