A study carried out by several Spanish research institutions has shown that the use of drones to measure temperature, humidity, light and concentration of carbon dioxide in greenhouses can help improve climate control systems and the monitoring of crops, since the capacity of the aerial robot to move in three dimensions and position sensors anywhere is an advantage over other alternatives, such as sensor networks.
The study has been led by researchers of the Group of Robotics and Cybernetics (RobCib) and the Centre for Automation and Robotics (CAR), which is a mixed centre of the Polytechnic University of Madrid (UPM) and the Higher Council for Scientific Research (CSIC) seeking greater precision in crop control.
Nowadays, many greenhouses have advanced systems to control the climate or supply water or nutrients to plants. Greenhouse agriculture requires careful climate control, in addition to the monitoring of crops. There is therefore the need to measure certain environmental variables continuously and accurately.
An aerial robot powered by four propellers called Quadcopter (or Quadrotor) has been used to carry out the project. The use of these aerial robots is spreading thanks to their small size, which can vary from a few decimetres to a metre or two. Other advantages are their low cost (some are available for a few hundred euros), manoeuvrability and the large amount of equipment they can carry, such as cameras or sensors.
The Quadrotor has been equipped with sensors for temperature, humidity, light and concentration of carbon dioxide, as well as a device to collect measurements and send these figures through a wireless network. Researchers have conducted an analysis of computational fluid dynamics, which has shown the optimum position for these sensors and demonstrated that the flow of the propellers does not interfere in their measurements. The Quadrotor can follow programmed routes autonomously by the greenhouse or move freely in search for abnormalities in the measurements.
Lastly, all systems have been tested in an experiment in a greenhouse located in Almeria's "plastic sea". The robot has flown across the whole greenhouse in about 20 minutes and created maps for temperature, humidity, light and concentration of carbon dioxide. These maps can be used, among other things, to ensure that the environmental conditions are suitable for plant growth or to detect temperature and humidity leaks caused by defects in the covers.
This work has been published in the journal Sensors and has opened the door to the use of drones in greenhouses to perform different tasks. At present, these research projects developed in universities, such as the UPM, are starting to be marketed by several companies. In light of studies like this, it is quite likely that their use will become essential in the future.
Source: rtve.es