Asset inspection indoors and in confined spaces comes with intrinsic difficulties, regardless of whether your procedures are drone-based or using traditional methods such as the use of scaffolding and climbing.
A 3D scanning Lidar of the type discussed in this article is mounted on the Scout137 Drone System.
Dangerous environments, hazardous access and a lack of ambient light result in serious safety concerns when working at height or in tight spaces. Drones and other tech-assisted inspection methods help minimise that risk, but present other navigational problems especially for non-entry or beyond line-of-sight operations.
The combination of confined spaces and steel structures interferes with GPS and magnetic compass-based systems, rendering them useless in most cases. In places where such technology fails, relying on only a video camera feed for navigation is far from optimal.
Using an inspection drone equipped with 3D Lidar scanning technology instead of GPS makes all the difference indoors and in other confined spaces.
What is Lidar?
Light Detection and Ranging (Lidar) is a remote sensing technology that uses pulsed laser light to measure physical distance. In short, it rapidly fires laser beams and measures the time it takes for emitted light to travel to the nearest surface and back.
3D Lidar scanning technology has been used in many industrial applications for years, in everything from agriculture and aviation to geosciences, to measure precise information about the physical world.
The automotive future is all about the self-driving car. Billions of dollars are invested into the development of autonomous driving. A key question is whether it can be achieved with or without Lidar sensors. Tesla, with their great market share, are betting on combining regular camera technology with Machine Learning: An enormous amount of collected data enables the use of cheap cameras instead of Lidar for this task. More basic driver-assist functions are covered by radar or ultrasound sensors.
On the other hand, Chinese automotive company Xpeng invest heavily on Lidar technology and plan to use Lidar as part of their sensor package for autonomous driving. They believe cameras alone will not be enough.
Something that cannot be covered by using camera-based navigation is the absolute lack of ambient light. Confined industrial spaces, like storage tanks, silos, maritime vessel cargo rooms etc. are often pitch black on the inside, very self-similar and represent volumes too large to light up all at once. Here, the use of conventional cameras for navigation becomes difficult and less robust.
But the Lidar sees also in absolute darkness, with great range and good accuracy.
Using proven 3D Lidar technology together with our advanced software, we have created a synthetic GPS system. Just as with a GPS drone, the operator can fly in ‘position mode’ supported by 3D Lidar data. This keeps the drone in place and ensures anti-collision, while the operator focuses on the images.Nicolai Husteli, CEO ScoutDI
The OS series of sensors from Ouster are very good for confined spaces. They are lightweight which allows them to be carried by a drone, they have good range, and come at a reasonable cost.
We chose these 3D Lidar sensors because of the ideal compromise of properties and value for money. They can also be used for capturing mapping data about complex environments such as forests and building interiors. But for us, the sensors let the drone see what you cannot see.
Overcoming indoor navigation problems
The 3D Lidar mapping technology is integrated and built-in to the Scout 137 Drone. Thanks to its combination of 3D Lidar sensor, vertical laser sensors and a powerful onboard computer, the Scout 137 drone knows where it is at all times. Adding precise situational awareness increases safety and gives greater confidence in the results of an asset inspection procedure.
This remains true regardless of lighting conditions. No ambient light is needed for navigation so inspections can be conducted with confidence, even in complete darkness. Of course, light is required to generate useful visual inspection data. But it is only required locally. You only have to light up the parts of the surface that are in front of your inspection camera.
Benefits of Lidar for the drone operator
If the drone operator doesn’t know what is next to or behind the drone, the inspection process can be impacted by confusion and lack of overview. This poses a direct safety threat, threatens the integrity of data quality and coverage, and risks damage to the asset and the drone itself.
While GPS navigation isn’t feasible indoors, a Lidar-enabled system is an ideal option. Lidar provides situational awareness to the operator and data to the autopilot to keep the drone stable and avoid obstacles.
“Using proven 3D Lidar technology together with our advanced software, we have created a synthetic GPS system. Just as with a GPS drone, the operator can fly in ‘position mode’ supported by 3D Lidar data. This keeps the drone in place and ensures anti-collision, while the operator focuses on the images”, explains ScoutDI CEO Nicolai Husteli.
The Scout 137 is tethered with a lightweight cable to a ground station and all the data is available in real-time via the robust, high-speed data link to the operator using the Scout tablet. The operator sees the live camera feed on-screen with the 3D map generated by the Lidar, giving a comprehensive overview of the inspection target in real-time.
The 3D map can be zoomed, panned or rotated to whatever angle will provide the best insights for drone operations. You can also of course explore and interpret the data after the inspection has finished.
Connecting the ground station to the internet allows remote participants to join a live-streamed inspection and see the same visual and 3D Lidar data in real-time via the Scout Portal, that the operator sees on his tablet.
Have confidence in data coverage
The on-the-fly mapping makes it easy to location-tag findings at critical points such as stiffener welds and bracket toes. and even easier to find them again in future inspections. But Lidar also helps to overcome the problem of you don’t know what you don’t know.
How does a drone operator know with confidence that 100% of the infrastructure has been inspected? This is a tough challenge in big, confined spaces where everything looks the same with repeating, self-like structures. Another benefit of the Scout 137 is that the flight path of the drone is recorded together with the 3D map generated from the 3D Lidar scans during the inspection. So, the drone operator knows with confidence when the inspection is complete and can demonstrate this to any stakeholders.
Lidar improves asset inspections now and in the future
Not only does this give the operator confidence in the completion of a full inspection, it also increases the speed of the activity, reducing asset downtime and thus overall cost. The live-streaming capabilities support remote inspection, which offers yet more cost and efficiency benefits.
The results generated by the 3D Lidar technology also help maintenance engineers to better plan future inspections since both visual and 3D data will be available for the inspection planning process.
Find out more about the capabilities of 3D Lidar and the Scout 137 asset inspection drone by watching this free on-demand webinar.