# Design and Comparative Analysis of a Ground-Level Trellising Tool for Greenhouse Tomato Cultivation
## 3 Results  
### Final Design of the Tool  
This section outlines the materials used in the construction of the tool. The materials were selected based on the criteria of strength, durability, and efficiency to ensure optimal performance under the intended conditions. Figure 10 illustrates the key components and their interconnections within the tool. The main components of the tool and the properties of each are described in Table 3.  
The tool was designed to optimize efficiency and enhance worker ergonomics during greenhouse trellising. This innovative tool features a telescopic carbon fiber mast with an adjustable length, enabling operators to perform tasks at height without the need for lifting platforms or ladders. By eliminating the risk of working from a height, the tool significantly increases operator safety, reducing the potential for workplace accidents. The tool allows for the handling of plants weighing up to 8 kg; beyond this weight, ergonomic issues may arise for the worker. According to the plant weight measurements taken in the greenhouse, 99% of plants are below 8 kg. When plants with higher weights are encountered, it is advisable to adopt measures such as pruning unwanted stems or harvesting the fruit to reduce the plant's weight. It is worth noting that this issue would not only affect the use of this tool but also pose difficulties for any current trellising method. Additionally, \begin{table}
\begin{tabular}{l c c} \hline \hline \multicolumn{1}{c}{**Parameter**} & **Greenhouse 1** & **Greenhouse 2** \\ \hline Soil and irrigation & Sandy soil and drip irrigation \\ Surface & 5500 m\({}^{2}\) & 10 000 m\({}^{2}\) \\ Tomato variety & “Bacco Cocktail” & “Bacco Cocktail” \\ Professional experience of the & 9 years & 8 years \\ evaluated worker & & \\ Knowledge about working at & Basic & Basic \\ heights & & Ladder, manual \\ Methods to be evaluated & scaffolding, silts, and & Motorized scaffolding \\  & the newly designed tool & \\ Frequency of visits per evaluator & 4 days & 1 day \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Greenhouse characteristics. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multicolumn{1}{c}{**Risk Level**} & \multicolumn{4}{c}{**Consequences**} \\ \cline{2-5}  & & **Slightly Harmful** & **Harmful** & **Extremely Harmful** \\ \hline \multirow{3}{*}{Probability} & Low & Trivial & Tolerable & Moderate \\ \cline{2-5}  & Average & Tolerable & Moderate & Important \\ \cline{2-5}  & High & Moderate & Important & Intolerable \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Risk levels according to the INSST method. Adapted from [29]. it improves productivity by allowing easier and more precise access to elevated areas. Figure 11 shows an image of the farmer performing the trellising task with the prototype built from the final design of the tool. To ensure that the tool can roll and unroll the raffia, a minimum torque is required. This minimum torque, provided by the DC motor, was calculated using Equation (2), resulting in a torque of 5.27 N\(\cdot\)m. A compact DC motor reducer was installed, providing a torque of 6.45 N\(\cdot\)m, operating at 12 V, and delivering a power of 15 W.  
The electrical circuit (Figure 12) must supply power to three 3 W electromagnets and a 15 W motor, all operating at 12 V. A simple switch controls the activation of the electromagnets, while a three-position switch controls the motor's rotation system. The circuit connections are made using two parallel circuits, one controlled by the simple switch, supplying power to the three electromagnets, and another parallel circuit controlled by the three-position switch to manage the motor's rotation. These connections are made with 2.5 mm\({}^{2}\) copper conductors. The power supply requirements were calculated using Equations (4)-(6), resulting in a total power demand of 24 W and a capacity of 16 Ah to power the tool for an 8 h workday. A 17 Ah battery was installed in the tool.