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INTRODUCTION
Diverse technological systems have been introduced in Cuba that include innovative harvesting machines, seeders and transport with auto-tipper. With the aim of reducing damage to sugarcane fields as a result of mechanized harvesting, the transport system named step transport or cane transshipment is introduced, by means of self-tipping trailers or semi-trailers pulled by medium and high-power tractor within the field and the use of trucks with trailers to transport cane towards the tipper of the industry (Paneque, 1988). The objectives of introducing this technology are to reduce the costs of the harvest and to improve the quality of the material that goes to the industry (Paneque et al., 2018; López et al., 2021).
Sugarcane harvest is a rigorous process, which requires a high degree of organization and coordination of all the factors that intervene in the technological process. Harvesting consumes an average of 40% of the expenses dedicated to cane production, so maximum organization is required in all its actions, from the field to the tipper to optimize it through the instrumentation of new technologies like: new harvesting equipment, organization based on computerization and fleet control through geo-positioning (Paneque, 2010; Daquinta et al., 2018).
Castillo et al. (2021) state that the evaluations of agricultural machines are generally carried out according to the Cuban standard Iagric (2013), by utilizing the photo-timing method to identify the times used in the production process and to define the exploitation indicators of the agricultural sets and self-propelled machines (sugarcane harvesters). Within these investigations, those carried out by the following authors are mentioned: Suárez et al., (2006a; 2006b); Matos & López (2011); Daquinta et al. (2014); de la Rosa et al. (2014) and others.
In Cuba, losses arise from the organization of the transportation of sugarcane that are not immediately solved. In the specific case of the Base Business Unit (UEB), Attention to Sugarcane Producers “Héctor Molina Riaño”, not only industrial problems have arisen, but also organizational and productive problems have emerged (Rodríguez et al., 2020).
In the case of transport, the biggest problem is defined by the imbalance between the number of combined and the number of means of transport. Due to this, the operational time of the transport does not exceed 40%, fundamentally given by the high rate of transport interruptions (about 50% on average), due to the wait for the supply of cane, interruptions of the combined and the wait to unload the tipper (Suárez et al., 2006a; Matos et al., 2010).
Taking into account the aforementioned, the objective of this work is to develop the DCMT automated system, to determine the amount of means of transport necessary in the mechanized harvest of sugarcane, for different exploitation conditions.
MATERIALS AND METHODS
Characterization of the Technological Process, of the Mechanized System for Harvesting and Transporting Sugarcane
During the sugarcane cutting by the harvester, a moving tractor with a tipping trailer moves parallel to it while it is being filled, later, they move full to the head of the field, filling the truck and the trailers coupled to it, where the trailer trains are formed with the truck. Then, it is transferred to the sugar mill tipper of the plant where the download is carried out.
Methodology Used to Develop the Automated System
The implementation of a methodology for the preparation of the software, which implies the organization of chain processes, such as the mechanized harvest of sugarcane, allows accelerating the analyzes in the decision-making process, as is the case of the organizational systems in the farming. It is necessary to take into account all the variables that participate in the technological process such as: transportation distance, field performance, capacity of the means of transport, among others, allowing in advance the possible solutions.
In order to develop the automated system for determining the amount of means of transport (DCMT), the mechanized system of transport and harvesting of sugarcane was modeled using the SMCTCA software, developed by De las Cuevas et al. (2016), for different exploitation conditions.
As an optimization criterion, the maximum values of the time utilization coefficient were chosen during the technological process, guaranteeing that the combine does not stop during cutting due to lack of means of transport, that is, that the synchronization between them is the most rational.
From dissimilar SMTCA software runs for different operating conditions and capacities of means of transport (20 and 60 t), the behavior curves are defined, for different distances from the field to the sugar mill tipper of the plant (5, 10 , 20, 30, 40, 50, 60, 70, 80, 90 and 100 km) and eight field yields (20, 30, 40, 50, 60, 70, 80 and 90 t / ha).
A battery of behavior curves was elaborated for all the variants analyzed, defining the equations by means of a linear fit, which were the methodological basis for the calculation of the amount of means of transport, of the automated system DCMT.
Automated System for Determining the Quantity of Means of Transport in the Mechanized Sugarcane Harvesting and Transport System
The "DCMT" system was developed on an EXCEL work platform for Windows, based on the synthesized flow diagram shown in Figure 1. According to this scheme, the amount of means of transport is determined for eleven distances from the field to the sugar mill tipper (Lx, 5 to 100 km), depending on the performance and load capacity of the means of transport selected. In addition, it provides the behavior graph of the aforementioned variables.
The system consists of an interactive Main Control Panel (Figure 2), which allows the user to link with each of the parts that comprise it. It is used for the selection of field performance in the control format of multiple selection and simple selection, to choose the capacity of the means of transport. It also has a hyperlink button that allows the transfer to the spreadsheet for determining the means of transport (Figure 3), where a panoramic view is offered in the form of a table, depending on the distance and agricultural yield, as well as, a graphical behavior, which allow defining quickly and precisely the need for means of transport, for the operating conditions selected above.
Within the Control Panel there is also an "About" button, which accesses the names and surnames of the authors, version, logo and address of the work center, etc.
All the parts that make up the automated system have a hyperlink button that accesses the Main Control Panel quickly.
RESULTS AND DISCUSSION
In order to carry out an analysis of the variation experienced by the rational amount of means of transport, according to the criterion of maximizing the coefficient of utilization of the harvesters' time, based on the automated DCMT system, the evaluation of this system for the CASE combine was carried out. It has field yields of 40 t per hectare and utilizes Howo Sinotruk truck (20 t) and two trailers of 20 t each as means of transport.
In Figure 4, it can be seen that, up to a distance of 40 km, the most rational variant, from the point of view of the maximum coefficient of time utilization, is the one that uses three means of transport with a total capacity of 60 t. Higher than this distance and up to 80 km, the variant that uses three means of transport is the most rational and with five for a distance between 90 and 100 km, between the field and the sugar mill's collection center.
This behavior is acceptable, since as the transportation distance increases, a greater quantity of means of transportation is necessary to guarantee a stable behavior of the time utilization coefficient, in an environment of 80%. This allows a stable productivity of the harvester and minimal operating costs of the mechanized system of harvesting and transportation of sugarcane.
CONCLUSIONS
The automated system "DCMT" allows defining the quantity of means of transport, according to the criterion of maximum coefficient of utilization of the time of the harvesters, in the mechanized system of harvesting and transportation of sugarcane, for different exploitation conditions.
The application of the results of the "DCMT" system allow achieving a stable productivity of the harvesters, with the minimum operating costs, with the increase of the transportation distance.
The "DCMT" software is easy to use, accessing each of its component parts through the user's link to the Control Panel.
The results of the "DCMT" system make it possible to define the most rational, productive and economically advantageous variants of means of transport of the mechanized sugarcane harvest and transport system.
