# Wydział Mechaniczny / Faculty of Mechanical Engineering / W1

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### Przeglądaj Wydział Mechaniczny / Faculty of Mechanical Engineering / W1 wg Autor "Awrejcewicz, Jan"

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Pozycja Analysis of stability of the human gait.(Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2007) Mrozowski, Jerzy; Awrejcewicz, Jan; Bamberski, PiotrPokaż więcej Analysis of the gait stability of a man moving along an even surface with a constant velocity is presented. The stability criteria applied to biped robots, namely: the Zero Moment Point (ZMP) and the Ground projection of the Center Of Mass (GCOM) have been employed in the investigations. The analysis has been carried out on the basis of measurement data obtained from the human gait recorded wit h a digital camera.Pokaż więcej Pozycja Anisotropic friction sliding rule influence on the mechanical systems dynamics(Wydawnictwo Politechniki Łódzkiej, 2021) Wijata, Adam; Stańczyk, Bartosz; Awrejcewicz, JanPokaż więcej Anisotropic friction can produce friction force which is not collinear with a sliding direction. How much friction deviates from a sliding direction is described with a so-called sliding potential or equivalently a sliding rule. A sliding potential is often described with an ellipse or a superellipse. In this paper we propose an oval curve which provides piecewise continuous mathematical description for a sliding rule and fits better to the experimental results than a typical superepllipse. For an exemplary mechanical system it is shown, that an anisotropic sliding potential can lead to an unstable equilibrium position in the system. Furthermore, for what parameters the unstable equilibrium occurs differs between sliding potential models. We have tested four different geometrical models of sliding potential in this regard.Pokaż więcej Pozycja Asymptotic study of elastic half-plane with embedded punch.(Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2007) Andrianov, Igor V.; Awrejcewicz, Jan; Kirichek, Yurii A.; Koblik, Steve G.Pokaż więcej A contact problem for an elastic half-plane and an embedded rigid punch is studied. The employed mathematical model describes the behavior of a soil with embedded foundation. The analytical solution geverning the stress field behaviour is derived. Singular perturbation and complex analysis techniques are used.Pokaż więcej Pozycja Axially excited spatial double pendulum nonlinear dynamics.(Politechnika Łódzka. Wydział Mechaniczny. Katedra Automatyki, Biomechaniki i Mechatroniki., 2015) Ludwicki, Michał; Kudra, Grzegorz; Awrejcewicz, JanPokaż więcej Analysis of a 3D spatial double physical pendulum system, coupled by two universal joints is performed. External excitation of the mechanism is realized by axial periodic rotations of the first joint of the pendulum. System of ODEs is solved numerically and obtained data are analyzed by a standard approach, including time series, phase plots and Poincaré sections. Additionally, FFT (Fast Fourier Transform and the wavelet transformation algorithms have been applied. Various wavelet basic functions have been compared to find the best fit, e.g. Morlet, Mexican Hat and Gabor wavelets. The so far obtained results allowed for detection of a number of non-linear effects, including chaos, quasi-periodic and periodic dynamics, as well the numerous and different bifurcations. Scenarios of transition from regular to chaotic dynamics have been also illustrated and studied.Pokaż więcej Pozycja Conditions Regulating Tumor Cell Behaviour in Biological Systems with Memory of States(Wydawnictwo Politechniki Łódzkiej, 2021) Dzyubak, Larysa; Dzyubak, Oleksandr; Awrejcewicz, JanPokaż więcej For biological systems with memory of states there were found conditions which regulate tumor cell behaviour. These conditions depend on parameters of the multi-parametric space. Based on the Masing–Bouc-Wen’s framework, the state memory in the biological system was simulated by means of supplemental state variables (internal variables). The additional state variables were introduced into the generalized non-linear multi-scale diffusion cancer invasion model and the chaotic cancer attractors were found. To quantify chaotic cancer attractors, the technique based on the wandering trajectories analysis was applied.Pokaż więcej Pozycja Construction and 3D model of stand for investigating a non-ideal forcing in a nonlinear chain dynamics of self-excited oscillators with friction(Wydawnictwo Politechniki Łódzkiej, 2021) Rogala, Patryk; Olejnik, Paweł; Awrejcewicz, JanPokaż więcej The research involves application and research on a non-ideal forcing to modelling and identification of vibrating systems with friction. It is still an innovative approach in the numerical analysis of vibrations of mechatronic machines and devices. This will allow to make a much real numerical modelling and more efficient identification of nonlinear dynamic phenomena observed in vibrating systems with friction, and thus, a better modelling of such phenomena in computer programs. To obtain the goal, initial 3D model of the mechanical stand was made in the CAD software. Based on the 3D model, real stand will be built, and experiments will be held to obtain data that will be necessary to ensure correctness of the mathematical model, which also will be studied and developed.Pokaż więcej Pozycja Decomposition of the Equations of Motion in the Analysis of Dynamics of a 3-DOF Nonideal System(2014) Awrejcewicz, Jan; Starosta, Roman; Sypniewska-Kamińska, GrażynaPokaż więcej The dynamic response of a nonlinear system with three degrees of freedom, which is excited by nonideal excitation, is investigated. In the considered system the role of a nonideal source is played by a direct current motor, where the central axis of the rotor is not coincident with the axis of rotation. This translation generates a torque whose magnitude depends on the angular velocity. During the system operation a general coordinate assigned to the nonideal source grows rapidly as a result of rotation. We propose the decomposition of the equations of motion in such a way to extract the solution which is directly related to the rotation of an unbalanced rotor. The remaining part of the solution describes pure oscillation depending on the dynamical behaviour of the whole system. The decomposed equations are solved numerically. The influence of selected system parameters on the rotor vibration is examined. The presented approach can be applied to separate vibration and rotation of motions in many other engineering systems.Pokaż więcej Pozycja Design and simulation of a lower limb exoskeleton with linear electric actuators(Wydawnictwo Politechniki Łódzkiej, 2021) Grzelczyk, Dariusz; Jarzyna, Olga; Awrejcewicz, JanPokaż więcej In the present study, we proposed and investigated a relatively simple and inexpensive construction of a lower limb exoskeleton driven by linear electric actuators and controlled by an Arduino microcontroller board. Moreover, to study crucial kinematic and dynamic parameters of the proposed device, we developed a general, three-dimensional simulation model of the exoskeleton in Mathematica software. To control individual joints of the investigated exoskeleton, we employed time histories of human joint angles in normal gait, recorded with the use of a motion capture system. As a result, we developed a novel human gait generator, which can be used to produce rhythmic movements in hip, knee and ankle joints of both limbs. Finally, the developed control approach was verified with the use of the constructed prototype of the exoskeleton.Pokaż więcej Pozycja Double pendulum colliding with a rough obstacle.(Politechnika Łódzka. Wydział Mechaniczny. Katedra Automatyki, Biomechaniki i Mechatroniki., 2015) Sypniewska-Kamińska, Grażyna; Starosta, Roman; Awrejcewicz, JanPokaż więcej The externally excited and damped vibrations of the double pendulum in the vertical plane are considered. The pendulum can collide with a rough obstacle many times during its motion. The pendulum is modeled as a piecewise smooth system. The differential equations govern the motion of the system in the relatively long time between the collisions. When a contact with the obstacle occurs, the pendulum exhibits a discontinuous behaviour. The velocities of both parts of the pendulum and the reaction forces are changing stepwise. An important element of the solving algorithm is aimed on the continuous tracking of the position of the pendulum in order to detect the collision with the unilateral constraints and to determine the state vector of the pendulum at the impact time instant. A single collision is described by the Euler’s laws of motion in the integral form. The equations are supplemented by the Poisson's hypothesis and Coulomb’s law of friction. The friction law is formulated for the instantaneous values of the reaction forces. The values of their impulses depend on the existence of a slip between the contacting bodies. Furthermore, during the collision the dynamic behaviour may change. Therefore the Coulomb law cannot be generalized for the linear impulses of the forces in a simple way. We have applied the Routh method in order to solve the problem. The method has a simple geometrical interpretation in the impulse space.Pokaż więcej Pozycja DSTA-2015 Conference Books vol. 1(Politechnika Łódzka. Wydział Mechaniczny. Katedra Automatyki, Biomechaniki i Mechatroniki., 2015) Awrejcewicz, Jan; Kaźmierczak, Marek; Mrozowski, Jerzy; Olejnik, PawełPokaż więcej Proceedings of the 13th Conference „Dynamical Systems - Theory and Applications" summarize 164 and the Springer Proceedings summarize 60 best papers of university teachers and students, researchers and engineers from whole the world. The papers were chosen by the International Scientific Committee from 315 papers submitted to the conference. The reader thus obtains an overview of the recent developments of dynamical systems and can study the most progressive tendencies in this field of science.Pokaż więcej Pozycja DSTA-2015 Conference Books vol. 2(Politechnika Łódzka. Wydział Mechaniczny. Katedra Automatyki, Biomechaniki i Mechatroniki., 2015) Awrejcewicz, Jan; Kaźmierczak, Marek; Mrozowski, Jerzy; Olejnik, PawełPokaż więcej Proceedings of the 13th Conference „Dynamical Systems - Theory and Applications" summarize 164 and the Springer Proceedings summarize 60 best papers of university teachers and students, researchers and engineers from whole the world. The papers were chosen by the International Scientific Committee from 315 papers submitted to the conference. The reader thus obtains an overview of the recent developments of dynamical systems and can study the most progressive tendencies in this field of science.Pokaż więcej Pozycja DSTA-2015 Conference Books vol. 3(Politechnika Łódzka. Wydział Mechaniczny. Katedra Automatyki, Biomechaniki i Mechatroniki., 2015) Awrejcewicz, Jan; Kaźmierczak, Marek; Mrozowski, Jerzy; Olejnik, PawełPokaż więcej Proceedings of the 13th Conference „Dynamical Systems - Theory and Applications" summarize 164 and the Springer Proceedings summarize 60 best papers of university teachers and students, researchers and engineers from whole the world. The papers were chosen by the International Scientific Committee from 315 papers submitted to the conference. The reader thus obtains an overview of the recent developments of dynamical systems and can study the most progressive tendencies in this field of science.Pokaż więcej Pozycja DSTA-2017 Conference Books - Abstracts(Wydawnictwa Uczelniane Politechniki Łódzkiej, 2017) Awrejcewicz, Jan; Kaźmierczak, Marek; Mrozowski, Jerzy; Olejnik, PawełPokaż więcej Pozycja DSTA-2017 Conference Books vol. 1(Lodz University of Technology Press, 2017) Awrejcewicz, Jan; Kaźmierczak, Marek; Mrozowski, Jerzy; Olejnik, PawełPokaż więcej Pozycja DSTA-2017 Conference Books vol. 2(Lodz University of Technology Press, 2017) Awrejcewicz, Jan; Kaźmierczak, Marek; Mrozowski, Jerzy; Olejnik, PawełPokaż więcej Pozycja DSTA-2017 Conference Books vol. 3(Lodz University of Technology Press, 2017) Awrejcewicz, Jan; Kaźmierczak, Marek; Mrozowski, Jerzy; Olejnik, PawełPokaż więcej Pozycja DSTA-2019 Conference Books vol. 1(Lodz University of Technology Press, 2019) Awrejcewicz, Jan; Kaźmierczak, Marek; Mrozowski, JerzyPokaż więcej Pozycja DSTA-2019 Conference Books vol. 2(Lodz University of Technology Press, 2019) Awrejcewicz, Jan; Kaźmierczak, Marek; Olejnik, PawełPokaż więcej Pozycja DSTA-2019 Conference Books – Abstracts(Lodz University of Technology Press, 2019) Awrejcewicz, Jan; Kaźmierczak, Marek; Mrozowski, Jerzy; Olejnik, PawełPokaż więcej Pozycja DSTA-2021 Conference Books – Abstracts(Lodz University of Technology Press, 2021) Awrejcewicz, Jan; Kaźmierczak, Marek; Mrozowski, Jerzy; Olejnik, PawełPokaż więcej From Preface: This is the sixteen time when the conference “Dynamical Systems – Theory and Applications” gathers a numerous group of outstanding scientists and engineers, who deal with widely understood problems of theoretical and applied dynamics. Organization of the conference would not have been possible without a great effort of the staff of the Department of Automation, Biomechanics and Mechatronics. The patronage over the conference has been taken by the "Excellent Science" program of the Polish Ministry of Education and Science. It is a great pleasure that our invitation has been accepted by so many people, including good colleagues and friends as well as a large group of researchers and scientists, who decided to participate in the conference for the first time. With proud and satisfaction we welcome 748 authors from 52 countries all over the world. They decided to share the results of their research and many years experiences in the discipline of dynamical systems by submitting many very interesting papers. This booklet contains a collection of 364 abstracts, which have gained the acceptance of referees and have been qualified for publication in the conference edited books.[...]Pokaż więcej