A flying robot equipped with an on-board stereo camera and sensors has autonomously navigated its way through a mine.
Developed by researchers at the German Aerospace Center (DLR), the multicopter was given a defined destination and then tasked with navigating autonomously to its target by creating a map of the test site using its onboard equipment.
‘We deliberately selected a location in which the challenges faced by the navigation system were particularly demanding,’ said Korbinian Schmid from the DLR Robotics and Mechatronics Center.
According to DLR, the airborne system found its way through the mine’s passageways, demonstrating for the first time the principle of autonomous flight under challenging environmental conditions and without external navigation aids such as GPS.
DLR believe future systems would fly into buildings in disaster-stricken areas, or map changes in mines over a long period.
Facing difficult lighting conditions at a coalmine in Recklinghausen, Germany the flying robot was asked to overcome air turbulence in the narrow passages, swirling dust, an uneven floor, slanted walls and obstacles such as machines and generators while arriving safely at the destination its operator had pre-defined over a wireless network.
To navigate safely, the flying robot’s on-board computer combines measurements of acceleration and rotation rates it receives from the sensors with the relative orientation and position measurement data that the stereo camera provides.
The estimated positions are then put to further use in combination with the images provided by the airborne system’s stereo camera to continuously create a map of the surroundings.
DLR further claims that the flying robot always knows its position, its orientation and the speed at which it is travelling, and is able to autonomously plan the trajectory it must take to reach its defined destination.
Once created, the map is sent to the operator over a wireless network for mission planning. If the wireless connection between the multicopter and the operator fails, the system has a choice to continue along its independent flight towards its destination or return to a previously defined point, such as the mine entrance.
If obstacles appear the aircraft stops and hovers until it receives new commands.
So far, the multicopter carries its own source of illumination in the form of LED spotlights, and the stereo camera covers a field of view of around 60 degrees.
‘What we would really like to do is enlarge this field to make it truly panoramic,’ Schmid said in a statement. ‘Additionally, we want to be able to consider the altitude and the dynamic properties of the system when planning a trajectory.’