Grzegorz Suchanek

Analyzing air pollutants is of key importance for the environmental protection goals. High concentrations of particulate matter (PM) have a particularly negative impact on human life and health. The use of an autonomous multirotor flying robot (drone) for the purposes of locating PM sources requires the design of a dedicated measurement system from scratch. The aim of this study was to make the most important design decision, which is the correct localization of the inlet of the measurement system, taking into account disturbances in the flow field caused by the rotors. To achieve this, a computational model was built with the use of a finite-volume method in Ansys Fluent software. Based on its results, a novel criterion was proposed and applied. In addition to the trivial position outside the rotors on the extended arm, it gave the second location in the space limited by the rotors below the robot. Finally, a robot prototype was built, and a series of verification experiments were carried out, first indoors and then outdoors, at different levels of ambient PM concentrations with and without a pollution source. The field results were compiled as histograms and scatter plots and clearly demonstrated the validity of the adopted criterion. The determination coefficient between measured concentrations showed a stronger relationship when the rotors were operating. Furthermore, in cases with a present pollution source, higher concentrations were observed around the internal sensor, making it more suitable for the studied application.

The aim of the work was to create a CFD model of the flow generated around the drone to estimate the impact of field parameters on the results of actual measurements from PM sensors that are positioned differently in relation to the propellers. The model created with the use of the ANSYS Fluent software allowed one to determine the criterion of their sufficient distance. The robots with four, six and eight rotors were analyzed. For these, the turbulence intensity, velocity and pressure distributions were determined. The paper also presents the results of PM measurements carried out under field conditions using two sensors mounted on the hexacopter robot.

The use of flying robots for various environmental protection issues is a very important and current research topic. Designing a dedicated multi-rotor flying robot is necessary for the efficient and automated localization of sources of air pollution, especially solid particles. In particular, one of the most important requirements that must be met by such a robot is its appropriate impact on the measurement process, i.e., increasing the sensitivity of sensors or reducing the interference. This is particularly difficult because its rotating rotors introduce significant disturbances to the surrounding fluid. In these studies, the design process is supported by the creation of a mathematical flow model and a series of analyzes to optimize the PM measurement system. The model is built using the finite-volume method in ANSYS Fluent software and steady-state RANS averaging. First, a flow field model with one propeller was modeled and its parameters identified by comparison with the results from the dedicated original dynamometer stand -- characteristics of the propeller performance. On the basis of the simulations and measurement of one rotor, subsequent systems of the highest practical importance are built. The effect of that design process was the preparation and testing of a functional robot prototype. The field parameter distributions resulting from the analyzes, in particular the turbulence intensity, allow one to propose a criterion on the basis of which both the best rotor configuration and localization of sensors are selected.

Polluted air causes enormous damage to human health. There is a high demand to find a solution for locating the places of illegal waste incineration due to the persistent smog problem. The use of multi-rotor drones for that purpose has now become one of the important research topics. The aim of the work was to check the possibility of using simple algorithms to search for the source of pollution. The algorithms that require low computing power, which may be part of the robot’s measurement and the control system’s internal software, were considered. The focus was on building a system based on a single robot that independently searches an area of a certain size. The simulation of the accuracy and scalability of the three different search algorithms was analysed for areas up to 200 m × 200 m. Two multi-rotor robots were prepared for the fieldwork. The validation of the two selected algorithms was carried out in outdoor environmental conditions. The fieldwork tests were carried out in areas with a maximum size of 100 m × 100 m. The obtained results were different, in particular on the wind speed and direction and the intensity of the pollution source. The random influence of these factors can verify the operation of the proposed system in practical applications. The difference between the true and the position of the source indicated by the robot was up to 15 m. That difference depended on the mutual arrangement of the measurement points and the pollution source location.

The drone is an unmanned aerial vehicle. Currently, many commercially available remote controlled flying toys are used to be called drones. This is an erroneous nomenclature, because the drone must have an autonomus flight function implemented. Due to it's simple mechanical construction, the most popular drones are in the form of a multirotor, in which arrangement the engines are placed in one plane. One of the most important advantages of this type of robots is the ability to maintain a certain position in space. Today, this allowed for e.g. taking photos from the air or inspecting hard-to-reach places. For use for environmental protection purposes, drone equipped with appropriate sensors and instrumentation may be used to monitor air pollution. The mechanical part of a quadrocopter flying robot was based on a TAROT frame with a 450mm engines spacing. The frame has been expanded with a dedicated set of legs to raise the clearance up to 150mm. Four dedicated EMAX MT2213 electric motors were installed on the frame, which are the main drive. They are characterized by the propeller hub-free-mounting, which minimizes possible imbalances. A single engine cooperating with a dedicated 10-inch propeller and a 4.5-inch pitch generates a maximum thrust of a 0.85kg. In the case of this system, it sums to a total of 3.4 kg. The weight of the ready to flight robot is 1.35 kg. To power the robot, a lithium-polymer battery with a capacity of 2.2 Ah is used, providing flight time of about 8 minutes. The basic work mode of the robot is a manual one, which means a self leveling mode with manual control. In addition to this mode, an autonomous navigation mode using GPS coordinates has been implemented. This navigation mode was also been tested during field tests. The operation of this navigation mode is very similar to the position maintaining mode, but operates on a larger scale. The robot in this mode is vectorically controlled, performing forwards/backwards and sideways movements to the set location.