**2. Precision agriculture: UAV integration**

UAVs are found in a wide range of applications in PA due to their advantages over the use of current agricultural machinery. Their flexibility and a high degree of autonomy, along with low labor needs and avoidance of crops and soil damage, significantly increase agricultural productivity and sustainability. The efficient use of chemicals in agricultural production is crucial in order to reduce harm to human health and also to reduce costs. UAVs can be an effective and inexpensive alternative to conventional spraying, and applications can be extended to crop fertilization, seed sowing, and similar activities. The equipment in charge of spraying can be relatively easily retrofitted to this type of aircraft, which further reduces the cost of the system. In terms of system autonomy, a multirotor type of UAV is able to perform precision pesticide spraying missions given the specifics of the crop, the severity of the disease or pest, the location, and other requirements. The key thing in carrying out the mission is precisely controlled droplets deposition on the target and reducing the environmental pollution. Several UAV system parameters need to be considered, including flight route (path pattern), spraying height, flight speed, nozzle flow rate, number and orientation of nozzles, and others. There are several commercial smart spraying systems, and one of the most used all-in-one solutions is DJI Agras (**Figure 1**) [41].

Multirotor unmanned aerial vehicles intended for plant protection can be used on flat plots but also hilly and extremely uneven terrain. The application of an aerial robotic system for smart spraying missions in the rural area of Hrvatsko Zagorje, which is characterized by hilly terrain (relief), was considered, where typical landscape is shown in **Figure 2**. Apart from the demanding terrain, the problem is the fragmentation of plots and an uneven distribution of crops (by square footage and shape). Besides, some plots are very difficult to access with the machinery currently in use because there are very narrow roads between plots that are often unorganized, and some plots do not have any access roads. The abovementioned implies the need to design a flexible robotic system that can be used on parcels of wider square footage. In this chapter, the concept of an aerial robotic system consisting of a mobile base station and a multirotor UAV armed with spray equipment and a tank is considered. The possibility of performing vertical take-off and landing of a multirotor type of UAV allows easy docking of the aircraft with the base station.

A base station is a mobile multifunctional docking facility that has several functions. From the aspect of system planning and control, the essential component is a computer with associated modules that send and receive wireless signals from the aircraft online and also serve as an interface between the user and the aircraft. The mission parameters can be set via the base station, i.e., the flight can be planned based on the tasks that the aircraft needs to perform. The base station will determine flight parameters (path, speed, height) based on the required pesticide amount for specific area and the volume of spraying tank. Mission parameters determine the course of

*Autonomous Aerial Robotic System for Smart Spraying Tasks: Potentials and Limitations DOI: http://dx.doi.org/10.5772/intechopen.103968*

**Figure 1.** *DJI Agras MG-1 commercial aircraft [42].*

**Figure 2.** *Presentation of a typical landscape in Hrvatsko Zagorje characterized by small and irregular plots.*

execution since this type of system can be used for different dimensions of plots and can also be used to perform a task on several plots. The base station should be able to change the batteries as needed for the mission and recharge the tank. After the aircraft completes the first part of the task and consumes the chemical, it returns vertically to the base station to fill up the tank and replace the battery. After the change, the aircraft performs a vertical take-off and continues to perform the task of spraying at the place where it stopped before loading. It follows from the above mentioned that the base station must be designed in such a way as to enable aircraft take-off

**Figure 3.** *Schematic representation of the concept of an aerial robotic system.*

and landing, two-way communication, easy and safe replacement of batteries, and pump to fill up the tank. In addition to the listed basic functions, the base station can also have a module (generator) for charging batteries. **Figure 3** schematically shows the concept of an autonomous aerial robotic system consisting of a multifunctional mobile base station and a multirotor aircraft for smart spraying tasks.
