Keywords: Indoor Localization, GPS-Free Localization, Ultra-Sonic, Industrial Application, Low-Cost Implementation
Motivation: Grain of various sorts is normally stored in silos. Due to heat, humidity, insects, etc, this grain might get spoiled, which results in hugh amounts of money losses for farmers worldwide. Mixing is a surprisingly simple care action for which Wellenbrock, has developed a special-purpose robot (see figures above). The robot propels by lifting some grain and pushing it backwards, and it steers by switching on and off either of the two motors.
(1) developing an appropriate indoor localization method that operates in silos with up to 50×50 m in size,
(2) the localization precision should be at least 40 cm, and
(3) the installation costs should not exceed € 1000.
This project has explored the following approaches:
(1) measuring the time-of-flight of (ultra-)sonic signals,
(2) employing two-dimensional position sensitive photo diodes (2D-PSD) , and
(3) CCD-camera-based image processing.
(1) Ultrasonic: precision of about 21 mm at an effective range of up to 20-25 m.
(2) Sonic: precision of about 40 mm at an effective range of up to 50 m.
(3) 2d-PSD: The results for the two-dimensions, position-sensitive photo diode were not conclusive and very much depend on the actual lighting conditions.
(4) CCD camera: still under investigation.
Poster: Further information can be found on the poster.
Contact: Ralf Salomon