Modelling and simulation of a waste sorting mechatronic system for multi-floor residential buildings

. The paper presents modelling and simulation of a mechatronic sorting system for residential buildings where the “wet” garbage can be used as fuel in an energy generation system. The proposed system can be used for the implementation of a selective storage model in the actual garbage chute system. The proposed system will have five different storage capacities that can be recycled: paper, glass, plastic packaging, metal boxes and organic household waste.


Introduction
Waste collection is not done at source; instead, the garbage is thrown through a garbage chute system, where reaches the garbage storage room on the ground floor of the building from where it is loaded manually into garbage collection machines. Also, storage is a real problem [1][2][3][4][5][6][7][8] and in this paper, we present a solution that enhance actual systems for a selective, sorting and storage system to obtain selective packages that can be recycled.
In literature, many papers or studies present similar systems for waste management systems implemented in different countries [9][10][11]16] dealing with automated sorting systems [12][13]. These solutions have some important disadvantages regarding costs, maintenance and use. Therefore, we propose a low-cost solution for garbage chute system with four or six distinct routes for dumping the waste that can be used in multi-floor residential buildings. The system consists of a garbage chute with door access from each floor and four storage devices for waste placed in a ground room.
The proposed system addresses the issue of selective collection of the following types of waste: -glass, glass containers made for beverages and food, jars; -newspapers, magazines, paper-cardboard packaging, folded cardboard boxes; -plastic packaging, plastic beverage containers (PET) and dairy products. Containers for cosmetics and detergents, plastic and polystyrene cassettes, plastic dishes, noncontaminated household waste plastic bags, plastic food containers; -metal packaging, such as cans, beverage doses; -organic household waste. According with the legislation, until 2025 [14], all the buildings must have a room on the ground floor, properly arranged, with four special containers for paper, glass, plastic and metal, plus the household. But it is hard to believe that the inhabitants on the upper floors will come down to throw the garbage in the especially designed places. Nevertheless, it will be preferred that the convenient and fast solution as outlined in this paper.
2 Study on rotation of the mobile waste sorting element From the point of view of waste sorting, this study is essential to determine the position of the garbage container. Elements of kinematic modelling of mechanisms were used [15,17]. The kinematic modelling refers to the fundamental principle of forming mechanisms, according to which a mechanism is made up of an active modular group and a passive modular group, the number and nature of which are dependent on the degree of freedom and the number of independent contours. The degree of mobility puts into evidence the number of independent variables that define the state of motion of the mechanism. The position function is where k=1…M (M=degree of mobility), j=1…2N (2N=number equation of independent loop), x k are independent variables and y j are dependent variables.
From Eq. 1 using derivation in function of time results the velocity.
We can rewrite Eq. 5 as Using the above relationships, several trajectories of the mobile waste sorting element were determined using a numerical software.
The mechanism of waste sorting is presented in Fig.1 and the trajectory will be generated by the mobile sorting element at different rotation angles in Fig. 2.

Modelling and simulation of a mechanical waste sorting system
The mechanical waste sorting system is made of five slots for: glass (green); metals (yellow); plastic (red); paper (blue) and household waste (the free fall section) as can be seen in  For kinematic modelling, it was used realized each part and then combined into an assembly, resulting the desired waste sorting system.
In Fig. 4b we present how it was simulated of garbage (interrupted line), to place the garbage container within these limits. The place where the garbage container is located could not be established, as there are several variables regarding the waste: weight, density and form, but there are some tests in progress and the results will be included in a future study. was used a 3D simulation software, before that it was realized each part and then combined into an assembly, resulting the desired waste sorting simulated the minimum and the maximum trajectory the garbage container within these limits. The fixed place where the garbage container is located could not be established, as there are several variables regarding the waste: weight, density and form, but there are some tests in progress and the results will be included in a future study.  These were focused on the actuation system and on the door. A 10N load is considered as constantly distributed over the sorting element, a sliding element at the side edge opposite the clamping member and a rotating element at the shaft of the engine (Fig, 5a and 5b). This is the most disadvantageous case where the entire load will fall on the engine spindle (which should not happen accidentally), for that mechanism of waste sorting has a screw nut elements. The deformation of the mobile sorting element is present in Fig.6. The second simulation considered a concentrate force of 10 N placed in the middle of the structur is the most disadvantageous situation (Fig, 7a and 7b). Deformation of the mobile sorting element obtained using FEM.
These were focused on the actuation system and on the door. A 10N load is considered as the sorting element, a sliding element at the side edge opposite the clamping member and a rotating element at the shaft of the engine (Fig, 5a and 5b). This is the most disadvantageous case where the entire load will fall on the engine spindle uld not happen accidentally), for that mechanism of waste sorting has a screw nut elements. The deformation of the mobile sorting element is present in Fig.6. The second simulation considered a concentrate force of 10 N placed in the middle of the structure that is the most disadvantageous situation (Fig, 7a and 7b). he greatest deformation of the mobile sorting element occurs takes directly the weight of the trash. The maximum deformation of the mobile sorting element appears at the contact between the selector margin and the garbage chute. This is due to the unbalanced attachment to the gripping element. In order to be verify model we have developed a small-scale model of the mechanical sorting system because the solution needs a coherent approach to deliver a workable technical solution. This experimental model was imperative to implement the control and the electronic part of the mechanical sorting system. The prototype (Fig. 2) is using four step motors type 42BYGHW609 with a power control done using a L298N driver. The automation of the system was made using the Arduino MEGA 2560 and four control buttons, one for each sort of waste.

Conclusions
In this article, was presented the 3D modelling and simulation of a mechanical waste sorting system. We verified the mathematical model using a specialized software, and it was realized the kinematic analyze. Also, a finite element analysis was performed to see the static mechanical behavior mobile of the sorting element .
To evaluate the theoretical results, a small-scale model was made which includes the automation software. In the near future, we want to test a real system in the existing system in the residential buildings.