Wydział Mechaniczny / Faculty of Mechanical Engineering / W1
Stały URI zbioruhttp://hdl.handle.net/11652/1
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Pozycja Influence of a relatively high frequency structure vibrations on the dynamics of real stick-slip motion(Wydawnictwo Politechniki Łódzkiej, 2021) Olejnik, Paweł; Górniak vel Górski, Adrian; Cebulak, Maciej; Awrejcewicz, JanThe work concerns the research on the impact of structure vibrations on the dynamics of frictional contact of bodies moving in relation to each other and remaining in frictional contact, causing a stick-slip motion. A literature review was carried out, describing mainly the phenomena concerning friction, but also the dynamics of vibrations and non-ideal energy sources that induce system oscillations. In the next step an experimental station for investigation of friction equipped with a new subsystem inducing high-frequency vibrations is presented to propose a modified physical model of the investigated frictional system. After analysing the most important factors influencing the behavior of the tested system, a mathematical description was prepared, which in theory showed the potential influence of the attached subsystem on the dynamics of the movement of the tested object - the frictional connection. Various methods of implementing the unbalance of rotors, being the source of highfrequency excitation, have been considered. At the final stage, a series of measurements of the displacement of the vibrating block on the moving belt was performed with the highfrequency excitation turned on and off. The prepared graphs were used to analyse the dynamics of frictional contact and the impact of non-autonomous vibrations on the occurrence of the stick-slip phenomenon.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, JanThe 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.Pozycja Mathematical Modelling of an extended Swinging Atwood Machine(Wydawnictwo Politechniki Łódzkiej, 2021) Yakubu, Godiya; Olejnik, Paweł; Awrejcewicz, JanAn extended model for a variable-length pendulum’s mechanical application is being derived from the Swinging Atwood Machine (SAM). An electrical component consisting of an electromagnet and armature coil is attached on the link connected to the counterweight mass on the left-hand side of the modified SAM to provide an excitation force for the system when an electric current is induced. The extended SAM presents a novel SAM concept being derived from a variable-length double pendulum with a suspension between the two pendulums. The equations of motion are simulated to see the trajectory of the two pendulums. The results of original numerical simulations show some compact regions of attraction at some regimes. Therefore, the extended SAM’s nonlinear dynamics presented in the current work can be thoroughly studied, and more modifications can be achieved. The new technique can reduce residual vibrations through damping when the desired level of the crane is reached. It can also be used in simple mechatronic and robotic systems.Pozycja Drive-by-wire of a converted into electric car Syrena 105 enabling Hardware-In-Loop tests of driving(Wydawnictwo Politechniki Łódzkiej, 2021) Adamski, Paweł; Olejnik, PawełIn this work, replacing an electronic throttle pedal and a driver in an electric car converted into electric by a hardware-in-loop workbench is described, highlighting the advantage of drive-by-wire feature that appeared after conversion. Drive-by-wire facilitates replacing a driver by Hardware-In-Loop (HIL) workbench, as instead of simulating a mechanical pedal depression by a servomechanism, electric signals can be transmitted directly from the workbench. Thanks to one-pedal-driving feature of the motor controller used in the car, there is a possibility of performing a variety of road tests replacing only the electronic throttle pedal. Hardware interventions in the car are described and sample HIL test results are presented.