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EN
In the article the results of simulation and experimental studies of the movement of a four-wheeled mobile platform, taking into account wheel slip have been presented. The simulation results have been based on the dynamics of the four-wheel mobile platform. The dynamic model of the system motion takes into account the relationship between the active and passive forces accompanying the platform motion, especially during wheel slip. The formulated initial problem describing the motion of the system has been solved by the Runge-Kutta method of the fourth order. The proposed computational model including the platform dynamics model has been verified in experimental studies using the LEO Rover robot. The motion parameters obtained on the basis of the adopted computational model in the form of trajectories, velocities and accelerations have been compared with the results of experimental tests, and the results of this comparison have been included in the paper. The proposed computational model can be useful in various situations, e.g., real-time control, where models with a high degree of complexity are useless due to the computation time. The simulation results obtained on the basis of the proposed model are sufficiently compatible with the results of experimental tests of motion parameters obtained for the selected type of mobile robot.
PL
Celem pracy jest zaprezentowanie sprawdzenia poprawności tezy, czy możliwe jest określenie wartości chwilowych mocy pojazdu pod kątem ich wykorzystania do wyznaczenia charakterystyki mechanicznej silnika spalinowego, elektrycznego lub napędu hybrydowego, podczas eksperymentów ruchowych pojazdu. Artykuł poświęcony jest różnym sposobom przetwarzania danych pomiarowych, uzyskanych z akcelerometru 3D w trakcie ruchu pojazdu.
EN
Currently, accelerometers are installed in the majority of commercially available smartphones. The paper proposes the use of a 3D accelerometer installed in a smartphone to measure vehicle motion parameters. The measured values obtained were subjected to filtration using an approximation of the spline function, so that they could be used for further testing. The main purpose of the work is to check if it is possible to estimate the instantaneous power of the vehicle, which can be used to determine the mechanical characteristics of an internal combustion engine, electric engine or hybrid drive during physical experiments. The tests carried out allowed the estimation of vehicle motion parameters.
EN
Currently, triaxial (3D) accelerometers are installed in every smartphone, so paper proposes to use such an accelerometer in vehicle motion measurement. The work describes a conception of the utilization of 3D accelerometer in smartphone to the determination of the car speed and the estimation of a power on the vehicle wheels. The analysis of the results was conducted based on road measurements. The basic issues which were discussed: calibration of acceleration sensor and processing of acceleration signals with variable sampling time resulting from the properties of the smartphone operating system. The smartphone (iPhone 4s) uses the accelerometer LIS331DLH (in Microelectromechanical systems technology MEMS) 12-bit analog-to-digital converter for ±2g range. Moreover, the iOS system (ver. 9.3.5) was chosen because of the more stable sampling time than in the Android system. The article presents the following signal processing: 3D acceleration → longitudinal vehicle acceleration → vehicle speed →resultant power → power transmitted from the propulsion system.
PL
Praca opisuje koncepcję wykorzystania akcelerometru trójosiowego, instalowanego w smartphonie, do pomiaru prędkości pojazdu samochodowego oraz oszacowania mocy napędu przekazywanej na koła pojazdu. Analizę wyników przeprowadzono na podstawie pomiarów drogowych. Podstawowymi opisywanymi zagadnieniami są: kalibracja czujnika przyspieszenia oraz przetwarzanie sygnałów przyspieszenia o zmiennym czasie próbkowania urządzenia mobilnego.
PL
W artykule przedstawiono zagadnienia związane z badaniem własności dynamicznych pocisku rakietowego. Przedstawiono realizację badań zgodnie z następującą kolejnością: badania teoretyczne, eksperymentalne oraz weryfikacja. Stosując zasady modelowania, opisano budowę i dane techniczne pocisku rakietowego oraz wykorzystując program PRODAS, opracowano model fizyczny pocisku, w oparciu o który przeprowadzono badania symulacyjne. Wyznaczono charakterystyki masowe, aerodynamiczne oraz podstawowe parametry toru lotu. Następnie omówiono badania doświadczalne podstawowych charakterystyk dynamicznych. Porównanie wyników uzyskanych z badań eksperymentalnych i teoretycznych świadczy o poprawności opracowanego modelu.
EN
The paper has been intended to present the issues of studying dynamic properties of a rocket projectile. The study has been carried out and presented as the following sequence: theoretical analyses, experimental testing works, and their verification. With the theory of modelling applied, a physical model of a rocket projectile has been generated. A mathematical model has been formulated using the PRODAS software. With the latter one as the basis, simulation-based analyses have been made. Mass and aerodynamic characteristics and the most essential parameters of the flight path/trajectory have been found. What follows is the discussion of the experimental study of fundamental dynamic characteristics. Comparison of theoretically found results and those gained experimentally proves the generated model to be correct.
EN
Modeling of ship motions in waves concentrates in most applications on the response amplitude operator (RAO). This mathematically not demanding method of analysis is very attractive, but loses some essential information in certain situations. The objective of present contribution is to establish and investigate preliminary foundations for a seakeeping model as optimal for under keel clearance (UKC) estimation. A special attention was devoted to transients of motions, stationary harmonic motions, coupling between degrees of freedom, and the wave force transfer functions – all in the aspect of shallow water environment.
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