Sándor Hajdu

• PhD
• associate professor at University of Debrecen

We have introduced a novel approach to competency-based education in mechatronics from the undergraduate to the postgraduate level. What distinguishes this approach is the integration of modeling and control of sampled systems right from the beginning of the undergraduate education. It is achieved by changing the structure of the first-semester Cal...

The aim of this paper was to reduce the current spikes in battery-powered saw motors by designing and implementing a sliding mode model-following adaptive controller. The proposed controller reduces overcurrent consumption, improves system energy efficiency, and effectively maximizes battery runtime, especially under high-load conditions. By applyi...

At the Faculty of Engineering of the University of Debrecen we have dealt with the design and construction of electric prototype race cars for more than a decade. With a focus on more conscious design and racing we developed a vehicle dynamics simulation program, which can be used to generate the dynamics functions of the cars from their technical...

The defining scientific developments of our time would not have been possible without the use of simulations. The aim of the research is to create a simulation of a BLDC motor. When creating a simulation, great emphasis must be placed on defining the purpose of the simulation. This basically determines the structure and complexity of the model. The...

The goal of the research presented in this article is to create a vehicle dynamics model, with which can simulate the emissions and consumption data of buses. During the research we created a vehicle dynamics model with AVL Cruise software. This is a longitudinal vehicle model that can be used to analyze the behavior of the bus in the direction of...

MATLAB, Simulink, and Simscape are market-leading products in Model-Based Design (MBD). Applying acausal and causal modeling methods to model the physical plant and control algorithms of mechatronic systems results in high-fidelity virtual prototype models that can be used for Model-in-Loop (MiL) development. In this paper, an electric-driven vehic...

Absztrakt. Jelen cikkben mindkét végén befogott, téglalap keresztmetszetű gerendák hajlító rezgéséhez tartozó sajátfrekvenciák számítási módszereivel foglalkoztunk. Az említett sajátfrekvenciákat a gerenda egyszabadságfokú modelljén analitikusan, valamint a térbeli szilárdtest-, és a térbeli rúd modellek esetében végeselemes modális rezgésvizsgálat...

In most cases, when creating vehicle dynamics simulations, we need software that can speed up model creation and simulation. There are many programs on the market for this purpose, but they have different knowledge and user interfaces. We present in this article briefly introduces the use of one of the market's leading vehicle simulation software,...

In this paper, a review is presented on automotive vehicle dynamics modeling. Applied vehicle dynamics models from various application fields are analyzed and classified in the first section. Vehicle dynamics models may be simplified because of different reasons: several control/estimation/analysis methods are suitable only for simplified models (e...

In this paper, a parameter estimation method of the model-based design approach is applied to estimate the drag coefficient and the rolling resistance coefficient of a vehicle. In fact, a constant-force parameter (c_const) and a velocity-square-force parameter (c_square) are in the vehicle model, and these result in the sum force applied along the...

In this paper, a review is presented on automotive vehicle dynamics modeling. Applied vehicle dynamics models from various application fields are analyzed and classified in the first section. Vehicle dynamics models may be simplified because of different reasons: several control/estimation/analysis methods are suitable only for simplified models (e...

In this paper, a parameter estimation method of the model-based design approach is applied to estimate the drag coefficient and the rolling resistance coefficient of a vehicle. In fact, a constant-force parameter (c_const) and a velocity-square-force parameter (c_square) are in the vehicle model, and these result in the sum force applied along the...

A járműdinamikai modellek a modell egyszerűsítése alapján két csoportra oszthatók. Vannak egyszerűsített modellek, amelyek során elhanyagolásokkal élünk: ezek jellemzően a hossz-, oldal- és függőleges irányok közül nem tartalmazzák az összes irányt. Az egyszerűsített modellekre több ok miatt is szükség lehet: vannak szabályozási, becslési, valamint...

A járműdinamikai szimulációk készítésekor a legtöbb esetben szükségünk van egy szoftverre, amellyel meggyorsíthatjuk a modell készítését és szimulációját. Erre a célra számos program van a piacon, azonban ezek eltérő tudással és felhasználói felülettel rendelkeznek. Cikkünkben röviden bemutatjuk a piac egyik vezető járműszimulációs szoftverének has...

The aim of the study is to analyse and visualize the accuracy of two parallel manipulators. The kinematics are calculated using vectors and the Newton method. The accuracy is calculated based on the actuator errors, visualization is done with color shading. Calculations was done using MATLAB

In this paper a vehicle dynamics model is presented, which is an example that contains all the necessary aspects of making a decent vehicle model. Several examples show the use of such a model: basic vehicle dynamics phenomena can be recognized with the simulation of a detailed vehicle model. We are dealing with the connection between downforce and...

In the following the role and contribution of vehicle dynamics simulation to the development of race cars at the Faculty of Engineering of the University of Debrecen is presented. The application of the developed simulation program for the optimization of the car’s technical data, together with the principle and method of optimization, is also desc...

A következőkben járművek menetdinamikai szimulációjának a lehetőségeivel foglalkozunk. Az egyszerű kétkerék-modelltől kezdve, a valós futóművel rendelkező jármű tetszőleges útfelület mentén történő mozgásának a szimulációját mutatjuk be. A MATLAB, Simulink, valamint a Simscape nagyon jól használható eszközöket biztosít az előbb említett célok eléré...

A kutatás célja két párhuzamos manipulátor kinematikájának és munkaterének vizsgálata. A kinematikai vizsgálatok vektoralgebrával és a Newton módszerrel készültek el. A munkaterek konstans orientációval kerültek ábrázolásra. A dolgozat eredménye, hogy a két manipulátor kinematikája és munkatere összehasonlítható. A számításokhoz a MATLAB program ke...

The efficiency and accuracy of the modern positioning systems are crucial points in their design. The designers and engineers are highly motivated to find new methods and solutions to the accuracy problem with the biggest mobility and safety. Considerable numbers of solutions are on the market but only some of them can be used in medical industry....

The stacker cranes in automated storage/retrieval systems (AS/RS) of warehouses often have very high dynamical loads. These dynamical loads may generate harmful mast vibrations in the frame structure of stacker cranes which can reduce the stability and positioning accuracy of these machines. The aim of this paper is to develop controller design met...

In the frame structure of stacker cranes harmful mast vibrations may appear due to the inertial forces of acceleration or the braking movement phase. This effect may reduce the stability and positioning accuracy of these machines. Unfortunately, their dynamic properties also vary with the lifted load magnitude and position. The purpose of the paper...

A következőkben egy MATLAB környezetben kifejlesztett járműdinamikai szimulációs programot ismertetünk. A program a műszaki adatokból, mint bemenő paraméterekből, előállítja a jármű menetdinamikai függvényeit, és közvetve alkalmas a műszaki paraméterek optimalizálására. A programot a DE MK Gépészmérnöki Tanszékén tervezett és kivitelezett elektromo...

In the frame structure of stacker cranes during non-stationary phases of movement due to inertial forces undesirable mast vibrations may occur. This effect can reduce the stability and positioning accuracy of these machines. The aim of this paper is to introduce an accurate and quite simple dynamical model of single-mast stacker cranes, which is su...

This paper presents distributed parameter dynamical modeling capabilities of single-mast stacker crane structures. In the frame structure of stacker cranes due to external excitation or inertial forces undesirable structural vibrations may arise. These vibrations reduce the stability and positioning accuracy of stacker crane and causes increasing c...

The paper presents the reduction of mast-vibration of single-mast stacker cranes by using a robust controller. During non-stationary movement undesirable mast vibrations may occur. These vibrations can reduce the positioning accuracy of the machine. The aim of this paper is to present the design procedure from the dynamic modeling to robust control...

In the structure of single-mast stacker cranes due to external excitation forces undesirable mast-sway may arise. This effect reduces the stability and positioning accuracy of stacker crane and causes increasing cycle time of storage/retrieval operation. Thus it is necessary to reduce the mast sway in some way e.g. via motion control of stacker cra...

In our paper we introduce the main reasons and necessity of the dynamic analysis of storage and retrieval machine frame structures. The objects of modelling and several simplification conceptions are also analyzed. Finally, we summarize the mathematical tools and methods of modelling, the limits of these methods and the properties of results.

Budapesti Műszaki és Gazdaságtudományi Egyetem, Közlekedésmérnöki Kar, Építőgépek, Anyagmozgatógépek és Üzemi Logisztika Tanszék 1111, Budapest, Bertalan Lajos u. 7-9. Összefoglalás Elsődleges célunk, egy, a felrakógépek számítógéppel segített méretezésére szolgáló eljárás kidolgozása volt. Ez lehetővé teszi a változtatható bemenő paraméterek hatás...