International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Production levelling, also referred to as production smoothing (jap. Heijunka), is an effective method for reducing unevenness in the production process and maintaining better control over stock levels. It helps keep production at a steady pace and ensure the desired level of flexibility. The authors present a study aimed at developing a method for planning the inflow of products from the production process, intended to be used in the scheduling of levelled production. Focus has been put on finding the right combination of lot size and production interval which, assuming certain input parameters (order size and placement rate, initial stock levels), yields the best outcome in terms of timely/untimely order fulfilment and minimum and maximum stock levels.

For simulation of processes of compaction or forging of products from powder materials, a method of permeable elements is proposed. The essence of the method is to use elements whose shape is regulated in advance, and, unlike the finite element method, where the elements coincide with the material volumes and their masses are unchanged, here the masses elements are variable, and material can flow between adjacent cells. Examples of using the method for modeling the processes of forging of porous preforms in closed and open dies, as well as in a closed die with a compensation cavity, are presented.

On the basis of completed studies, including computer modeling of the morphology of the temperature field of heat pipes and thermal measurements in the framework of the experiment, a method was developed for diagnosing the quality of heat pipes with a symmetrical structure.

In this paper the results of modelling of radial-shear rolling process of austenitic stainless steel AISI-321 are presented. The simulation in Simufact Forming program complex was performed. The conditions of simulation for radial-shear mill SVP-08 of Rudny industrial Institute were adopted. The various parameters of stress-strain state (effective plastic strain, effective stress, mean normal stress and Lode-Nadai coefficient) and also microstructure evolution with rolling force were considered. It is revealed that radial-shear rolling is an effective process for obtaining of high quality round billets from stainless steels of austenitic class.

One of the main problems in the plastic deformation of materials is the determination of the coefficient of friction as well as the subsequent application of the simulation for comparative analysis. However forecasting process and matching between simulation and experimental data is still a problem. Causes of this are factors such as roughness, mechanical properties of the material, chemical composition, etc. which strongly influence the behavior of the material in the simulation of the process.

In this study, an approach is proposed to determine the changeable coefficient of friction in the deformation process experimentally, taking into account implicitly the influence of surface roughness on the friction curves. For the comparative analysis between experiment and simulation of the process, the experimental data for objective assessment was introduced. Nevertheless, there are differences between experiment and simulation, which is most evident in high loads, using lubricants differing from more than 12 units for graphite lubricant, with more than 6 units with oil and with dry friction with 8 units.

This research proposes modelling, simulation and implementation of autonomous unmanned quadrotor prototype based on Matlab Simulink software, and Mission Planner for communicating with APM control board of the quadrotor. The goal is to Control attitude and altitude over a desired trajectory of the Quadrotor using PID control, with high precision and reliability. The mathematical model used for simulation takes into account all differential equations of motion of the quadrotor. A full quadrotor prototype was assembled for real experiments to do a comparison between real and simulated data. This comparison reveals the reliability and the accuracy of the PID controller and the mathematical model used in Matlab.

In the paper, fuzzy logic is used to simulate active suspension control of a one-half-car model. Velocity and acceleration of the front and rear wheels and undercarriage velocity above the wheels are taken as input data of the fuzzy logic controller. Active forces improving vehicle driving, ride comfort and handling properties are considered to be the controller outputs. The controller design is proposed to minimize chassis and wheels deflection (sky-hook concept) when uneven road surfaces, pavement points, etc. are acting on tires of the running car. As a result, a comparison of an active suspension fuzzy control and a spring/damper passive suspension is shown using MATLAB simulations.

At the time of exploitation, the geometrical position of the control valve changes as a result of wearing, which leads to a change of residual electromagnetic gap stroke and force of control valve spring. The following study measures the hydraulic characteristic changes, based only on common rail injector increased stroke of control valve and residual electromagnetic gap. The results show that the increasing of control valve stroke and residual electromagnetic gap increase the fuel flow rate and return fuel flow. Increased fuel flow rate and return fuel flow are presented with short injector signal time and lower levels of working pressure. The increasing is lower with longer injector signal time and high level of working pressure. The follow-up results are practically significant by common rail electromagnetic injector diagnosing and repairing.

The paper deals with a variable multifunctional simulation tool that enables to design and assemble animated models of various technological processes controlled by externally connected fuzzy logic unit. It enables to verify the correctness of fuzzy controller settings in the future control of real technological processes in practice. This tool represents an effective, innovative, and creative concept important to understanding control approach of technological processes modeling as an insight to behavior of real industrial processes and their control which is based on fuzzy logic. On the base of this animated simulation, real technological processes control can be realized successfully according to producer demands afterwards. Models of technological processes assembled by this simulation tool can be then externally controlled by various control strategies (traditional PID controllers, ON-OFF controllers,PLC controllers, fuzzy logic controllers etc.) via a proper real controller connected to the computer. In the paper, two-conveyor-belt system for product packing is shown. The goal consists in control of synchronization of products and boxes placed on individual conveyor belts in order to pack the product into the box. The main concern here is to improve dynamic performance and control efficiency with the help of assembling an animated model of the controlled technological process and its external control by a fuzzy logic unit.

Web services are application components that can be linked together for creating new functionality. As such, they support industry environments by binding together inhabitant services with distributed on demand services for implementing the business strategies. However, web services are operating in dynamic environments and an important issue during the composition process is change management either at the local or at the web, in general. Therefore, service changes together with other nondeterministic behaviours must be efficiently propagated to ensure the validity and consistency of the enterprise plans. Simulations are effective tools for enhancing factory competitiveness. Simulating the operation of a developed composite service for verifying the developed product could be a solution to this problem. The results of the simulation will allow to predict and react to such behaviours before applying the developed service in real production. As such, this paper describes and compares the existing service simulators that could be used in smart industry environments in terms of their functionality. Based on this review, the identification of gaps in performing simulation of service composition in industrial environments is presented, and challenges to be met on the field are outlined.

A review of the existing methods applied to multi-criteria decision aiding has been made as well as the multi-criteria approach to a class of problems in the field of material science has been defined. The multi-criteria decision aiding has been successfully applied to determine appropriate compromise decisions about the examined parameters of a number of technological processes of welding, chemical thermal processing, iron covering, etc. The approach presented determines the values of technological factors satisfying the requirements of users simultaneously to a number of values examined and proposes a solution for the relatively highest thresholds at one and the same time

In the paper are presented the main theoretical techniques used for the modeling and simulation of industrial processes. The main focus is on the physical side of the theoretical techniques and their mathematical side is reduced to a reasonable minimum. Different theoretical approximations as thermodynamic and hydrodynamic levels are used.