Let’s start by saying that the list of fields of application of the drone as a tool for inspections and / or maintenance, is not exhaustive.
Let us therefore describe the main ones, paying attention to the peculiar aspects of the different types of inspection, which in fact characterize both the type of drone to be used, and the difficulties the pilot could face (wind effect, electromagnetic interference, reduced visibility , etc.). For the technical specs of the inspection drones, refer to the article “Inspections with drone – The technical specs of the drone” from the Blog.
The inspections of tanks-silos-cisterns-smokestacks assume flight at altitude (wind action) and in BLOS (see Drones – Acronyms and terms). In fact, the inspection may not be limited to only the external analysis, but – especially for the tanks – to an internal analysis with control of some structural and / or functional aspects, such as the state of the welds, or the state of the floats, etc.
For this type of inspection it is therefore necessary that the drone has an excellent photographic sector and that the pilot is very good at getting as close as possible to the element under investigation.
For this type of analysis, special drones are used, equipped with safety cages to avoid contact between the propellers and the walls of the product. The presence of an observer to help the pilot is therefore essential.
Inspecting a bridge or viaduct with the drone requires carrying out activities at high altitude in areas often very windy. The capture of details related to the deterioration and defects of batteries, supports, shoulders, pulvinus is the main purpose of the aerial survey.
Percolations, exposed irons, degraded iron covers are alarm bells that the drone must therefore capture, in order to allow an effective assessment of the state of the work. Often the drone has to fly flush with the deck to capture the degradation of the beams in concrete.
The activity is in VLOS (see Drones – Acronyms and terms), but requires the help of an observer. The drone for this type of inspection must have an excellent zoom camera, for the acquisition of quality images.
Mobile TLC systems (radio base stations)
Inspect a mobile TLC system means analyzing: the state of the RF connectors of the antennas, the tightening of the antenna bolts, the state of the sheaths of the RF cables. Also in this case the drone operates at altitude in mostly windy areas (a tower for TLC can exceed 60 meters in height).
During this type of inspection, the influence of the electromagnetic fields of the antennas on the radio link between the drone and controller must be kept in mind. Operations take place in VLOS, but also here the presence of an observer to assist the pilot is very important and helpful in capturing aerial data, together with an excellent zoom camera.
Power distribution airlines
The analysis of overhead power distribution lines is very similar to the analysis of mobile TLC systems. Knowledge of the conductor state, insulators, supports, the effects of erosion, cracks, assembly problems, knowledge of defects in general, are fundamental aspects for the correct operation of overhead lines.
Also in this case the electromagnetic fields of the high voltage lines can interfere on the radio link between the drone and the controller. Operations take place in VLOS, with the presence of an observer. Staying in hovering, at a certain distance, implies the need to install an excellent zoom camera on the drone.
The inspection of wind turbines with the drone is an activity that requires special expertise from the pilot, considering that the combined effect of the wind in the area with that generated by the propellers (if in motion), can play bad jokes.
The heights involved are considerable, and even here a drone with a zoom is necessary if you want to carry out a good inspection. A drone with good stabilization and with stable hovering will therefore allow you to grasp through the zoom those aspects due to erosion, fractures, splits both at the turbine level and at the propeller level once the system is off.
The drone for the inspection of solar fields must mount a dual camera: one in the visible and one in the near infrared.
The benefit of using the drone for the inspection of photovoltaic fields consists mainly in being able to perform a mapping of all strings over a period of time, in order to identify defects such as hot-spots, damage-oxidation of frames, state of the cover glasses, malfunctions of the coupling boxes, etc.
This type of inspection must be carried out in VLOS, and flight planners play a fundamental role, allowing you to plan the collection of thermograms according to very specific schemes.
The analysis of the facade of a building with a drone is not a simple activity, because it takes place in 95% of cases in urban dress, where you cannot fly unless with the necessary authorizations (if possible!). a drone for this type of activity must have an excellent zoom and must be equipped with a dual camera: one in the visible and one in the near infrared, as in the case of drones for inspections of photovoltaic fields.
In this type of inspection, the scan must take place up to the level of the top floor of the building, and for horizontal or vertical bands, in order to cover the entire facade. Wind, presence of people, often restricted urban areas are the challenges to be kept in mind in this type of inspection. This type of inspection is in VLOS.
Analyzing a roof, be it a pitched roof, or a vaulted roof, or a flat roof, in itself is not a complicated operation, except that the operation may have to be carried out in BLOS. This in fact depends on the position of the pilot with respect to the roof, the extent of this and the height of the roof with respect to the height of the ground.
In most cases the roofs are found in the urban area with the limitations already exposed for inspections of the facades of buildings.
If the inspection instead concerns an isolated building, or a shed in an industrial area, the limitations are certainly less. In the case of an isolated shed, a good flight planner can help the pilot considerably. Camera with excellent zoom is the basic requirement for a drone for this type of inspection.
In rural, forestry and environmental settings, the drone can play a fundamental role in inspections, especially as regards the riverbeds of streams and waterways in general.
The presence of branches, obstructions due to landslides, clogging of bridles and wells, can be easily detected by a drone with a good camera with a decent zoom. The inspection of collection channels, especially in urban areas, can then play a strategic role. In this case, a good lighting source generated by the drone is essential. These types of inspections are in VLOS.
Landslides and instabilities
Understanding the position of a fracture in the rocks, or the sliding state of a landslide, its extension, are fundamental aspects that only a reading from above can give.
The drone therefore for the inspection of landslides and instabilities is a fundamental tool. The ability to climb to altitude, operating in often windy areas, to capture an overview, a good hovering, stable to capture or film ridge and moving areas, with the possibility of zooming, are the requirements that an inspection drone for landslides and quenches must have.
This type of operation, carried out in VLOS, may require the help of a flight planner to capture relevant details with the aerial photogrammetric method.
As seen in this short summary, drones can carry out inspections in a short time and at significantly reduced costs compared to traditional methods.
Not only that, the role of drones both in inspections and in predictive and corrective maintenance can reduce if not completely eliminate the risks to which operators would be exposed, when engaged in maintenance and / or inspection activities in hard-to-reach places.
However, the difficulties associated with some types of inspection should not be underestimated, always remembering that the inspection activities must be entrusted to a pilot with a certificate for critical operations, and that in the event of an accident with the drone, the client is still responsible.
Note regarding the images: The images in the post are taken from pixabay.com, they are free for commercial use without attribution request; the author who is the legitimate owner is however mentioned for each image. The use of the images is exclusively for the purpose of a better understanding of the contents of the article. The highlighted image is taken from pixabay.com free for commercial use and without attribution request, the author is Public Co.
Last Updated on/Ultimo aggiornamento – 28/07/2020
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