Marian Lopatka

Dr. Marian Lopatka

Faculty of Mechanical Engineering, Military University of Technology, Kaliskiego 2, 00-908 Warsaw, Poland
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Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 April 2022 in Applied Sciences
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Journal Article
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KCKarol Cieślik
Karol Cieślik
Marian LopatkaMarian Lopatka
Marian Lopatka
Due to threats to human safety, remotely controlled manipulators are more and more often used to carry out rescue tasks in hazardous zones. To ensure high efficiency and productivity of their work, intuitive control systems are necessary, e.g., master-slave and drive systems that maximize the speed of working movements by copying the movements of the operator’s hands and are adapted to human perception and capabilities. Proper design of manipulator drive and control systems, therefore, requires knowledge of the acceleration and velocity of hand movements as signals controlling manipulators. This paper presents the results of tests of speed and acceleration in the implementation of the hand when making precise movements and moving objects over short distances (0.4–0.5 m) and during relatively long-distance reaching movements (0.73–0.93 m). Research has shown that, at short distances, the hand movements do not reach the maximum speed, while at longer distances, there is a period of constant maximal speed. In addition, studies have shown that the maximum speed of manipulation movements (longitudinal, lateral, and vertical) does not depend on the direction of movement. Moreover, precise movements were performed at a much slower velocity than reaching movements.

1 January 2018 in AIP Conference Proceedings
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ATAndrzej Typiak
Andrzej Typiak
Marian LopatkaMarian Lopatka
Marian Lopatka
Łukasz RykałaŁukasz Rykała
Łukasz Rykała
MKMagdalena Kijek
Magdalena Kijek
The work presents the dynamic equations of motion of a unmanned six-wheeled vehicle with mecanum wheels for rescue applications derived with the of Lagrange equations of the second kind with multipliers. Analysed vehicle through using mecanum wheels has three degrees of freedom and can move on a flat ground in any direction with any configuration of platform’s frame. In order to derive dynamic equations of motion of mentioned object, kinetic potential of the system and generalized forces affecting the system are determined. The results of a solution of inverse dynamics problem are also published.

2 August 2022 in Energies
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Marian LopatkaMarian Lopatka
Marian Lopatka
PKPiotr Krogul
Piotr Krogul
Arkadiusz RubiecArkadiusz Rubiec
Arkadiusz Rubiec
MPMirosław Przybysz
Mirosław Przybysz
The effective use of robotic manipulators is particularly important when carrying out hazardous tasks. Often, for this type of mission, manipulators equipped with a hydraulic drive system are used, and their work results primarily from the implementation of precise movements through their effectors. In heavy manipulators, limiting the uncontrolled movement resulting from high inertia and relatively low stiffness has an impact on the improvement of the control precision. Therefore, the paper presents experimental studies that allow the assessment of the impact of the use of counterbalance valves on the precision and dynamics of a manipulator with a hydrostatic drive system. The tests were carried out for a wide range of effector velocities along a horizontal trajectory, on the basis of which, it was found that it was possible to improve the precision and dynamics of the work of such manipulators due to the precision of the trajectory and pressures in the drive system.

16 October 2020 in Challenges to national defence in contemporary geopolitical situation
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Marian LopatkaMarian Lopatka
Marian Lopatka
The problem of dismounted operation support with Unmanned Ground Vehicles (UGV) often called robots is widely discussed and many solutions were tested to verify theory and find technological gaps and limitation for such application. In this paper the initial demand and requirements and their evolution is described on an example of US Army. Described changes concerns demanded level of autonomy, fire support possibility, possibility of performing combat engineer tasks, using UGV for reconnaissance, surveillance, and target acquisition, longitudinal and lateral stability, obstacle negotiation and overall terrain mobility and efficiency of make use of the “mule”.

11 December 2023 in Journal of Terramechanics
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DSDaniela Szpaczyńska
Daniela Szpaczyńska
Marian LopatkaMarian Lopatka
Marian Lopatka
PKPiotr Krogul
Piotr Krogul

19 August 2020 in Applied Sciences
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Marian LopatkaMarian Lopatka
Marian Lopatka
Arkadiusz RubiecArkadiusz Rubiec
Arkadiusz Rubiec
Heavy-wheeled vehicles with articulated hydraulic steering systems are widely used in construction, road building, forestry, and agriculture, as transport units and tool-carriers because they have many unique advantages that are not available in car steering systems, based on the Ackermann principle, such as—high cross-country mobility, excellent maneuverability, and high payload and lift capacity, due to heavy axles components. One problem that limits their speed of operation and use efficiency is that they have poor directional stability. During straight movement, articulated tractors’ deviate from a straight line and permanent driver correction is required. This limits the vehicles’ speed and productivity. In this study, we describe a driver-aid system concept that would improve the directional stability of articulated vehicles. Designing such a system demands a comprehensive knowledge of the reasons for the snaking phenomenon and driver behaviors. The results of our articulated vehicle directional stability investigation are presented. On this basis, we developed models of articulated vehicles with hydraulic steering systems and driver interaction. We next added the stabilizing system to the model. A simulation demonstrated the possibility of directional stability improvement.