# Evaluation of Autonomous Mowers Weed Control Effect in Globe Artichoke Field
## 2 Materials and Methods
### Experimental Set up and Design of the Two Trials  
#### 2.2.1 Trial 1: Performance Evaluation of Three different Autonomous Mowers  
In March 2021, the performances of three different autonomous mowers were tested. A Husqvarna Automower\({}^{\circledR}\) 310 (Husqvarna, Stockholm, Sweden), hereafter AM1, a Husqvarna Automower\({}^{\circledR}\) 550 (AM2), and a Husqvarna Automower\({}^{\circledR}\) 535 (AM3), were compared. Figure 1: Cumulative precipitations and maximum and minimum average temperatures recorded by the meteorological station in Bocca d’Arno (Pisa, Italy) (43°40°51.6′′ N, 10°16′48.0′′ E). These battery-powered machines operate following random trajectories within a defined area. The working area is delimited by a boundary wire, which produces an electromagnetic field. The autonomous mowers stop and change direction whenever they reach the boundary wire or hit an obstacle. The characteristics of the three autonomous mowers [35; 36; 37] are shown in Table 1. The AM1 (Figure 2a) was chosen for the trial because of its smaller size compared to the others, which could have allowed it to move more easily in confined spaces such as between artichoke plants. The AM2 (Figure 2b), on the other hand, was chosen as it is more of a performing machine, being equipped with a larger battery, a greater working capacity, a higher forward speed and a slightly higher cutting width than the others. Regarding the AM3 (Figure 2c), the choice is due to the fact that the four-wheel drive could have facilitated the movement of the machine in the field since it is within an agricultural context. Autonomous mowers were left to work on an area of 150 m\({}^{2}\) (25 \(\times\) 6 m) containing four artichoke rows and a buffer area of 18 m\({}^{2}\) between the base station and the crop rows. Autonomous mower's performances were evaluated based on the percentage of area moved and total primary energy consumption. Details about the above-mentioned assessments are reported in Section 2.3 (Data Collection). Based on previous experience in agricultural contexts, an acceptable weed control effect was achieved when the percentage of area moved was around 80% [25]. Thus, this level of coverage was assumed as the \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & & \multicolumn{3}{c}{**Autonomous Mowers**} \\  & & **Automower\({}^{\text{\textregistered}}\)** & **Automower\({}^{\text{\textregistered}}\)** & **Automower\({}^{\text{\textregistered}}\)** \\  & & **310 (AMI)** & **550 (AM2)** & **535 (AM3) 1 ** \\ \hline Type of engine & & electric & electric & electric \\ Dimensions (lenght \(\times\) height \(\times\) width) & cm & \(63\times 25\times 51\) & \(72\times 31\times 56\) & \(93\times 29\times 55\) \\ Vehicle weight & kg & 9 & 13.9 & 17.3 \\ Number of driving wheels & & 2 & 2 & 4 \\ Cutting width & cm & 22 & 24 & 22 \\ Working capacity & m\({}^{2}\)-day\({}^{-1}\) & 1000 \(\pm\) 20\% & 5000 \(\pm\) 20\% & 3500 \(\pm\) 20\% \\ Average moving time on one recharge & min & 70 & 270 & 100 \\ Average charging time & min & 60 & 60 & 30 \\ Blade motor speed & rpm & 2300 & 2300 & 2475 \\ Total power consumption during mowing 2 & W & 25 \(\pm\) 20\% & 35 \(\pm\) 20\% & 40 \(\pm\) 20\% \\ Max active time per day 3 & min\(\cdot\)day\({}^{-1}\) & 1080 & 1440 & 1440 \\ Standby time per day & min\(\cdot\)day\({}^{-1}\) & 360 & 0 & 0 \\ Forward speed & m\(\cdot\)s\({}^{-1}\) & 0.38 & 0.65 & 0.61 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Autonomous mowers’ main characteristics. Figure 2: The three autonomous mowers compared during the first trial: (**a**) AM1, (**b**) AM2 and (**c**) AM3. target of the studied machines. Each autonomous mower was set to work 3 h (charging time excluded). The three autonomous mowers were tested one at a time, six times each. 2.2 Trial 2: Comparison between the Weed Control Effect of Autonomous Mower and Conventional Weed Management  
From April to June 2021 a second trial was carried out to compare the weed control effect of the selected autonomous mower with the conventional weed management system.