project specification

Ardea

Ardea is a Micro Aerial Vehicle (MAV) which researches two major research directions for MAVs; autonomous exploration of unknown environments and cooperation with emergency teams in disaster situations. The MAV is well suited to operating in diverse environments, for example in collapsed buildings or on alien planets, where GPS positioning is not available and self-contained localization, navigation and mapping using on-board sensors is crucial.

Specifications

Length68 cm
Width68 cm
Depth30 cm
Weight2.4 kg
Flight time~10 m
Power supply4 S (14.8V) LiPo battery 7000mAh
On-board sensors4 VRmS-16/C-COB (1280 × 960px) • IMU
ProcessingIntel NUC with a dualcore i7 (3 GHz)
BeagleBone Black
Cameras1280×860 px

Overview

Ardea is well suited to operating in diverse environments, for example in collapsed buildings or on alien planets, where GPS positioning is not available and self-contained localization, navigation and mapping using on-board sensors is crucial.

Ardea has four Ultra-wide Angle Lens cameras which enable 240° view in the vertical direction. Therefor, Ardea has simultaneous coverage of the ground and directly above, facilitating navigation and mapping in narrow spaces such as caves. Additionally Ardea's FPGA runs Semi-Global-Matching (SGM) stereo image processing of the four cameras to produce depth maps which enable it to perceive the three dimensional world.

Ardea has a trigonal Y6 frame construction to be able to place the cameras in a way that they have a high coverage without having any parts from the MAV in their field of view.  It enables the MAV to fly in more confined areas such as indoors or in caves. Ardea is propelled by three 10” coaxial rotor pairs providing a maximum thrust of 3.6 kg.

The MAV consists of two main, separable parts:

  • Frame: includes all engines, speed-controllers and the outer carbon frame tubes.
  • Stack: consists of all navigation sensors and on-board computers.

The stack can also be operated by itself, which makes it easier to develop and test new hardware and software before incorporating it with the frame.  

Camera

Ardea provides  approx. 240◦ vertical field of view. In addition to the large FOV, the arrangement of cameras is well suited for the high dynamic range situation in outdoor scenes with often much higher brightness above the horizon than below. 

As separate cameras cover the FOV below and  above the horizon, longer exposure and higher gains can be used for the lower FOV to cope with the different intensities. The camera system consists of four synchronized cameras, each providing 1280×860px. Forachieving a large FOV and reasonable resolution in the vertical axis, the smaller image dimension (860px) of the camera sensors are horizontally aligned.  

References

Describes the technology, its preliminaries, wind velocity estimations, experimental setup, and results.

Teodor Tomic, Korbinian Schmid, Philipp Lutz, et al.

Describes the general hardware setup & multiple camera setup. Describes experiments and the results.

M. G. Muller, F. Steidle, M. J. Schuster, et al.

Wevolver 2022