# Quadcopters in Smart Agriculture: Applications and Modelling
## 2 Types of Quadcopters  
UAVs come in various types, each designed to fulfill specific missions and meet different operational needs. This section explores the different categories of UAVs, focusing on rotary-wing UAVs, particularly quadcopters. UAVs are divided into five types: blimps, flapping-wing, parafoil-wing, fixed-wing, and rotary-wing. Table 1 presents a comparison among them in terms of structure, advantages, and disadvantages. Among the pre-listed UAV types, blimps, flapping-wing, and parafoil-wing UAVs are rarely used in smart agriculture due to their specific limitations. In contrast, fixed-wing and rotary-wing UAVs are the most commonly selected for various agriculture missions [2]. Deciding between fixed-wing and rotary-wing UAVs depends on the specific mission requirements. For instance, fixed-wing UAVs are preferable for tasks that require longer flight durations and higher speeds, such as aerial mapping and monitoring over large agricultural areas [27; 28]. Conversely, rotary-wing UAVs are ideal for missions that require hovering and low-speed operations, such as collecting data from sensor nodes on the ground in crop fields [29; 30]. This paper primarily addresses rotary-wing UAVs, specifically quadcopters. These UAVs, characterized by having at least one rotor, are divided into several types, as illustrated in Figure 2. Among these, quadcopters are selected as the core focus of this work. This selection is not random; it is because quadcopters are the most popular UAVs in smart agriculture and are frequently used in research [15; 16; 17]. Their superior capabili \begin{table}
\begin{tabular}{c l l l l} \hline
**Type** & **Structure** & **Advantages** & **Disadvantages** & **References** \\ \hline \multirow{6}{*}{Blimps} & - Spheroid shape & - High endurance & - Low speed & [13; 18] \\  & - Lifting gas & - Most harmless in the case & - Larger in size compared to & [13; 18] \\  & & of clashes & other UAVs & \\  & & - Stay airborne even in the & - Lack of maneuverability & \\  & & & - Weightless, cannot carry & \\  & & & much of a payload & \\ \hline \multirow{6}{*}{Flapping-wing} & - Little wings to fly & \multirow{2}{*}{- Flexible shape} & - High energy consumption & [13; 15; 18; 19] \\  & imitating insects and birds & & - Very small & \\ \hline \multirow{6}{*}{Parafoil-wing} & - One or more propellers at & \multirow{2}{*}{- Carry larger payload} & - Very sensitive to weather & [13; 20; 21] \\  & the back for steering control & & - Carry larger payload & - Non-rigid connection & \\ \cline{1-1}  & \multirow{2}{*}{- Parafoil parachute} & - Benefit from the air power & between the parachute’s & \\ \cline{1-1}  & & to decrease the energy & suspension lines and the lift & \\ \cline{1-1}  & & consumption & produced complicates & \\ \hline \multirow{6}{*}{Fixed-wing} & - Fixed wings & - High endurance & -Need a runway to take off & [13; 18; 22] \\  & - Landing gear & - High speed & - High cost & \\ \cline{1-1}  & - Propeller & - Higher payload limit & & \\ \hline \multirow{6}{*}{Rotary-wing} & - At least one rotor & - Vertical Take-Off and & - Low speed & [13; 15; 18; 19; 23; 24; 25; 26] \\  & - Propellers & - Tail rotor and swashplate & - Ability to hover & - Shorter flight time & \\ \cline{1-1}  & & in case of helicopter & - High maneuverability & \\ \cline{1-1}  & & - Easy to build & - Can be used indoors & \\ \cline{1-1}  & & - Low-cost maintenance & & \\ \hline \end{tabular}
\end{table} 
Table 1: Different types of UAV. ties and unique features make them the go-to choice for many agricultural applications, outperforming other types of UAVs [31; 32; 33; 34; 35]. Theirs characteristics are summarized as follows:  
* Quadcopters support heavier payloads by generating a higher lift force through increased thrust from its rotors. The increased lift helps balance the extra weight, allowing quadcopters to stay stable and fly properly while carrying heavier loads;
* Hovering is a key feature that allows quadcopters to maintain a stable position in the air without moving.