Abstract: Upon striving to ensure the cargo safety and precizity of its delivery, mechatronic control systems are more and more widely applied in lifting mechanisms. They get information from various sensors, including those involved in registering the rope’s deformations. The got information may be distorted because of the appearance of cargo swinging that’s level depends on the mode of operation of the lifting mechanism and the rope’s elasticity. The latter varies dependently on the length of the unwound rope and the way of deformation of rope’s wires. In the paper, a mathematical model of a lifting mechanism that describes its dynamics on lifting when both the cargo and the rope swing in respect of a vertical axis is provided. The model was examined by a special program developed upon using MATLAB and SIMULINK program packages. The obtained dependences of the swing parameters on the mode of operation of the lifting mechanism and the rope’s parameters enable assessing a possible application of the lifting mechanism.
Abstract: The paper presents the model and design of a flexure-based precise 4 DOF degree of freedom positioning system for micro-positioning uses. The positioning system is featured with monolithic architecture, flexure-based joints and ultra-fine adjustment screws. The mathematical model for the output displacements of the positioning system has been verified by finite element analysis (FEA).
Abstract: The article discusses the results of experiments on the further development of the method for monitoring the state of the small samples of resin and polymers during curing. The applied method is based on a change in the structure of oscillating transducers leading to variations in the form and/or mode of oscillation. The thin layer of epoxy resin was placed between two piezoelectric transducers in the form of piezoceramic plates. Curing epoxy resin forms a bimorph and its characteristics change along with variations in viscosity or, after the gel point, stiffness. It is possible to establish the level of epoxy resin curing by monitoring changes in the resonance parameters of bimorph elements. The main purpose of cure monitoring of small samples is to develop a new method for evaluating the parameters of resin both before and after the gel point thus taking into consideration that the use of rheological data measured with reference to small samples will be applied for designing or interpreting bulk-flow processes where epoxy may be considered a continuum.
Abstract: The work presents a proposal of mathematical algorithm developed for analysis of piezoelectric stacks that consist of classical PZT piezoelectric transducers. The considered systems vibrate longitudinally. Piezoelectric plates are combined in order to obtain multiplied displacement of the system and ensure more effective operation. Using constitutive equations of piezoelectric materials and an equation of the single plate’s motion, a matrix of characteristics of the system was obtained. The matrix of characteristics consists of relations between mechanical and electrical parameters (forces, displacements, electric current and voltage) that describe behaviour of the system. A structural damping of the plate’s material was being taken into consideration using Kelvin-Voigt model of material and its influence on the plate’s dynamic flexibility was analyzed [1, 2]. A dynamic flexibility – relation between the plate’s deformation and a force applied to the system is considered. Using the obtained dependences and non-classical methods, characteristics of piezoelectric stacks were designated and presented on charts. The obtained results were juxtaposed with characteristics of the system without structural damping.
Abstract: This paper deals with the presentation of the new centering – leveling device developed in Vilnius Gediminas Technical University. Precision angle measuring systems are always combined of many mechanisms and devices which influence angle measurement accuracy. Therefore, every one of them has to be investigated separately. This device can be used as a separate device to perform a slight movement of measured object or it can be used as a part of mechatronic angle measuring system. This paper presents preliminary results of centering – leveling device minimum pitch determination and analysis of further development of this device as a part of mechatronic angle measuring system.
Abstract: Production of high precision circular scales is a complicated process requiring expensive equipment and complex processes to achieve. Precision angle measurement equipment tends to be very expensive and therefore not accessible to all in need. Simplification of production of such devices can lead to reducing costs of angle measurement systems ensuring easier accessibility. A new method of producing precision circular scales using low cost mass production can reduce the costs of these devices drastically. Therefore, utilising a common CD technology as the basis for such scales is analysed. This paper deals with the analysis of the newest laser cutting method for plastic circular scales. Preliminary results of manufacturing such scales are presented in the paper as well as measurements of the grating of the scale were performed. The quality of different scales manufactured using different laser types is analysed in the study. The cost – effective alternative of manufacturing circular scales is discussed in the paper.
Abstract: Due to their high power density and volumetric energy, lithium batteries are increasingly being employed as the source of energy in vehicles and mobile devices. Often, however, the individual cells have to be series-connected in order to reach the required supply voltage. As these cells, due to different production conditions, inevitably will differ in parameters (capacity, internal resistance, etc.), the result will be varying states of charge in these cells during operation. Because lithium batteries are damageable by a cell voltage that is either too high or too low, it is impossible to assure safe operation of the battery pack. So, in order to make lithium batteries operate safely, a battery management system is employed. Our contribution is about generating and applying a simulation model for the model-based development of functions for this battery-management system.
Abstract: Using a controller is necessary for any automation system. The controller must be cheap, reliable, user friendly and not cause any problems for inputs and outputs. Classical control systems like proportional integral derivative (PID) put adequate results of linear systems and continuous-time. In fact, real control systems are time-variant, with non-linearity and poorly calculated dynamic variables. For this reason, conventional control systems need an expert person to adjust controller parameters in general. Sometimes an operator is required to solve control problems. Human control is not completely reliable. Also, it does not include any electronic communication. In modern factories, every point must be monitored and electronically controlled from remote points when necessary. In this study, including every electronic communication channel, a simplified handling, low-cost, reliable, Fuzzy Neural Network Controller (FNNC) is designed.
Abstract: In this study, maximum bending stresses occurring on the rectangular aluminum beam under various small loads were measured with strain gauge, data acquisition cards and computer. Special software was developed to measure maximum strain and stress on the aluminum beam. Stress values occurring on the aluminum beam under various small loads were measured with strain gauge and those strain values were transmitted to computer directly with data cards. Using the strain, the load and other constant values of the material (Young’s modulus, dimensions, cross section area, load, Poisson’s rate, etc.), the stress values occurring on the beam are calculated and the stress-strain graph is drawn on the screen automatically. In this experimental study, the theoretical knowledge given in the books and experiment results obtained under laboratory conditions were compared with each other. The obtained results were almost 99% similar. Similar studies have characteristics that can be used to measure maximum bending and torsion stresses for real applications in the industry and mobile loading machines.
Abstract: Designing specific technical equipment requires solving a number of problems that consider the theoretical structures of particular technical means. In the case of mechatronics equipment, one should take into consideration three groups of problems: designing mechanical components, designing actuators and designing a control program . Moreover, it is important to properly organize the process for the purpose to obtain a coherent project linking the three above mentioned sub-systems of mechatronics equipment . Only when three sub-systems are properly designed, the whole system can appropriately and effectively operate. One should mention that the design process could be analyzed not only from the perspective of the partition of the main system but also from the perspective of design, material and assembly features [1, 3].Taking into account constraints providing for the design process, the procedures of creating the Stewart platform were followed. This platform was devised as an actuator of a car simulator [4, 5, 6, 7]. The process of designing was divided into the before introduced phases. First, the system of actuators was elaborated referring to information about the velocity and acceleration of a real car. Second, the control system was elaborated. The system was matched to the mechanical system of actuators. At the third stage, the control program was elaborated and tuned.All presented stages of the design process were computer aided so that the process of designing was conducted in virtual reality. It results in shortening the durability of the designing phase and in decreasing costs. This preparatory phase, including the realization phase, allowed preparing the real car simulator.