Transmission tower - Inspection parameters

This article will summarise the best practices and inspection parameters for inspecting transmission towers with Sterblue.

Sterblue's solutions allow for automated infrastructure inspections, thanks to two core technologies: Perception and Curiosity. 

Perception generates automated flight plans for your infrastructure inspections. 
Curiosity is Sterblue's proprietary AI, designed to automatically locate any defects. 

It is imperative to adjust your inspection parameters based on the equipment you use and the inspection environment, as the default parameters may not be optimized for your drone, lens or environment. 

2 types of drones are recommended for transmission tower inspections. DJI Matrice RTK serie or Phantom 4 Pro/Mavic 2 Pro series. The laters are sensible to magnetic interferences.

It is imperative to adjust your inspection parameters based on the equipment you use and the inspection environment, as the default parameters may not be optimized for your drone, lens or environment.
It is your responsibility to control the drone at all time and switch to manual flight mode if the drone sensors are disturbed.

Optimizing the inspection parameters used by Perception will allow for a more accurate inspection, and hence for better AI performance in detecting defects.

Recommended settings

General inspection parameters for the structure can be modified under the Parameters tab, but Sterblue recommends specific parameters depending on the side of the tower and the drone you are using.

Transmission tower trajectories are usually split into 6 sides, in the following order:

  • Side 1: Front right
  • Side 2: Right side insulator
  • Side 3: Rear right
  • Side 4: Rear left
  • Side 5: Left side insulator
  • Side 6: Front left

Inspection parameters can be modified on the right tab of the Sterblue Cloud when creating your mission, or in the Sterblue App when on site.

Inspection distance and angles

These side specific parameters can be accessed by clicking on the dropdown arrow to the right of the selected structure, as seen in the example below.

Removing Side

As can be seen in the gif above, the angle with line can be modified at the 4 corners of the tower (sides 1, 3, 4 & 6 ) in order to adjust the trajectory of the drone.

  • Increasing the angle will also increase the distance of the drone from the cables.
  • The inspection distance can also be modified for optimal precision.
  DJI Matrice 200 / 210 RTK DJI Mavic 2 or Phantom 4 Pro
Optics X5s+45mm or X7+50mm lens N/A
Inspection Distance
Insulator Sides 2 & 5

6m

5m
Inspection Distance Sides 1, 3, 4 & 6 10m 6m 
Angle with line
Sides 1, 3, 4, 6
45°
Increase angle if you feel this is too close to the cables
60° 

Minimum inspection height

The minimum inspection height parameter is designed to allow the user to avoid obstacles on particular sides of the tower. 
For example, should there be a telephone pole which is 7m high near side 3 of this tower, you should set the minimum inspection height to ~10m to ensure the operation is carried out safely. 

Activate or deactivate a side?

It is possible to remove one side entirely from the trajectory - this can be a useful feature to avoid obstacles or simply if the inspection of a particular side isn't required. Tension towers do not need to have the sides 2 and 5 inspected for instance as the insulator chain is horizontal.
The gif below shows the trajectory updating once "side 3" has been deselected. 

Screen Recording 2020-04-27 at 15.19.54.mov