Tuesday, 6 December 2016

The Use of Drones in Construction

 The Cutting Edge No. 2


This is a collection of reports on the web from the last year or so on how and where drones have been used. There is probably a lot of other research and use going on that is not available and has not been reported, or is not on company or university websites, but I think this gives a fair idea of the state of play.

Drones are the big new thing in construction at the moment, but as always with new construction technology it is hard to get a good idea of how widespread their use, is or indeed how useful they are. Given the rapid uptake of BIM, tablets and apps in the US industry (see here and here) its not surprising that they also appear to be at the cutting edge with drones. That said, its hard to know how good the integrated systems from Skycatch and Droneview actually are, as there are no independent reports available so far. On the other hand, these companies have already got commercial products onto the market, and appear to be the first entrants.

It is worth noting that one effect of drones that monitor site progress against plans and schedules will be greatly increased transparency of project performance. I’ll discuss that topic in a later post, but there are some obvious implications of quality real-time information for clients, contractors and workers, though different in each case.



Drones are in regular use at Crossrail, a big project in London about to finish, although as far as I can tell they only have two in operation:
  • Site inspections - close examination of high-risk areas, and speedy overviews of large sites, freeing up time for other tasks.
  • Health and safety Induction – site plans can be quickly and efficiently updated to show where different works are taking place ensuring that operatives stay safe.
  • Crane, tower and scaffold inspection – a much easier method of doing inspections, providing real-time footage to spot anomalies. This reduces site downtime and mitigates risks of personnel having to work at height.
  • Site planning – overviews can be obtained quickly to inform planning sessions.
  • 360° panoramas – a more immersive experience to enhance appreciation of potential hazards and site orientation.


The French company claims to be a leader in the field, with four subsidiaries using drones:
  • Omexom, the subsidiary that handles electricity grids, is using helicopter-style drones to observe the condition of pylons and insulator chains.
  • At Eurovia drones are used in quarries to carry out topographic surveys and measure the likely reserves of the aggregate.
  • Nymphea uses underwater drones, known as remote survey vehicles, to assess the condition of structures such as bridge caissons, either with visual cameras or with acoustic devices that measure the extent of corrosion on metal structures.
  • Vinci Autoroutes uses drones that hover about 100m above the ground to build a 360 degree picture of the landscape along a particular road. The idea is to enable clients to see themselves from above, which they can do by linking to the drone’s cameras with their mobile phones or tablet computers.



The US contractor’s drone programme is the result of its decision in 2013 to team up with Skycatch a Californian start-up that attracted investment from Google, among others. The firm was founded to build drones for data collection on building sites. Christian Sanz, the founder and chief executive of Skycatch, said the aim was to have a fleet of drones continually flying over the works to capture real time information about their progress, prevent mistakes and detect unsafe situations.

Bechtel uses the technology to collect real-time environmental data such as air quality and temperature, monitor safety, survey difficult and inaccessible terrain and track real-time construction progress. The data collected can be stored in a cloud and viewed on site using handheld and desktop computers using the Skycatch dashboard. The technology was used at Bechtel’s three Curtis Island LNG projects in Australia, which are more or less complete and now in production.


 

Komatsu’s Smart Construction uses automated dozers and excavators. Komatsu partnered with Skycatch, and claim to have created the world’s first machine-to-machine automated construction equipment. The Smart Construction initiative uses Skycatch autonomous aerial robots for data collection, point cloud maps with 1 cm accuracy, visual intelligence and advanced data analysis. Skycatch UAVs scan job sites to capture imagery and automatically generate accurate 3D site data. This data is then compared with 3D drawings of the site to automatically calculate the area and volume of earth to be moved. The results are transmitted as instructions to Smart Construction machinery for fully autonomous work on the site.



The company provides aerial imaging including 2D and 3D models to assist project managers, general contractors, site superintendents and engineers in tracking construction progress, measuring material stockpile volumes, improving environmental compliance, providing timely site surveys and real time mapping, improving safety and maintaining project schedules and budgets. Integrates with CAD and BIM software to facilitate collaboration and enhance real time decision-making.

They have a very interesting page on industry resources here. This lists 2016 conferences (all except one in the US, which was on insurance in London), a large number of software products, and drone insurance providers.



Their website doesn’t have a lot of information, but on this page they have some good videos, including the Sacramento Kings' stadium in California in the next item. I assume this means they provided the imaging for the software system under development there.



In August 2015, MIT Technology Review reported that drones were being used on the construction of the Sacramento Kings' stadium in California. Drone footage of progress on site was converted into a 3D model that could be compared to digital drawings to identify where progress was behind programme. The system was developed at the University of Illinois, where Mani Golparvar-Fard and his research team are developing GPS enabled quadcopters that will be computer-controlled to fully automate data collection, analysis and reporting of progress on the construction site. They have also developed a way for these robots to install cameras on elements of the site automatically.

In order to test and develop their system, the researchers were granted access to several construction sites around the U.S. being operated by Zachry Construction and Turner Construction, including their Sacramento Kings project. The University granted access to a current residence hall construction site, there is a video that shows the project on their campus at Urbana-Champaign.

Their system works this way: the quadcopters take photos and videos of the construction site, guided by a cloud-based computer program that can direct them to the rights spots, resulting in automatic data collection. The activities of the aerial robots are fully autonomous, including take off, navigation, landing and charging. The captured images and videos are then used to create an actual 3D model of the site under construction. The system compares this automatically generated 3D model to the as-designed 4D (3D plus time) Building Information Model, resulting in more frequent and complete progress monitoring information. The system also autonomously mounts battery-operated and WiFi-enabled surveillance cameras on different elements of the site to automatically capture videos of ongoing construction operations. Once the data is captured and transferred to the cloud, the system automatically detects and tracks workers and equipment in real time from the video feeds and categorizes activities of the resources automatically. The progress and activity monitoring results are visualized in a web-based, 4D augmented reality (D4AR) environment—a representation of the construction site in 4D with additional performance information superimposed on it. These D4AR models can also be made available to construction professionals through smartphones and tablets



Christian Eschmann is a researcher at the Fraunhofer Institute for Non-Destructive Testing IZFP in Saarbrücken, Germany, where he develops and adapts micro-aircraft for building inspections: “For a 20 by 80 meter wide façade, a test engineer needs about two to three days. Our octocopter (eight motors) needs three to four hours for this.” Cracks and other flaws can be digitally photographed in high resolution. If necessary, the octocopter can also be equipped with a thermal imaging camera, to check things such as building insulation.

The image yield is high, a15-minute flight can result in up to 1,200 photos. On the computer, the individual images are combined to create an overall picture, and the resulting 2D and 3D data models illustrate the visually imageable condition of the building structure. In the future, there will be software to delete any superfluous images. A complete software suite is planned for the future, including damage recognition, image processing, a database and documentation, as well as the automation of all operations, including stitching of individual images and identification of crack patterns. The octocopter took to the air in 2011 for its first inspection. So far, it has needed to be controlled manually. Eschmann and his colleagues are currently (in 2014) working on navigation sensors which will control the flying robot in the future. Following a predetermined pattern, these sensors will steer the octocopter along the façades, floor by floor, from one side to the other.



The UK contractor used a drone for surveying to capture detailed images of the construction path. Apart from surveying, the drone came in useful following a 2014 road traffic accident when it was flown in to record the incident scene and examine how local traffic management was set up.


This is the second in an ongoing series of posts about technology trends in the building and construction industry. The first is here.