Article citation info: (*) Tekst artykułu w polskiej wersji językowej dostępny w elektronicznym wydaniu kwartalnika na stronie www.ein.org.pl Prochowski L, wAch w, JAckowski J, Pieniążek w. experimental and model studies on the influence of the run flat tire damage on braking dynamics of the multi-axial special purpose vehicle. eksploatacja i niezawodnosc -Maintenance and reliability 2015; 17 (1): 118-128.
Leon Prochowski wojciech wAch Jerzy JAckowski wiesław PieniążekExpErimEntal and modEl studiEs on thE influEncE of thE run flat tirE damagE on braking dynamics of thE multi-axial spEcial purposE vEhiclE EkspErymEntalnE i modElowE badania wpływu uszkodzEnia opon run flat na dynamikę hamowania wiEloosiowEgo pojazdu spEcjalnEgo*
Tire damage, that occurs quite often during operation of special purpose vehicles (building, forest, military, agricultural heavyduty vehicles), affects a vehicle motion also during sudden braking. Motion of a four-axial vehicle has been analysed in order to evaluate the influence of tire damage (cracking, tearing) on its behaviour during sudden braking and based on that to evaluate the possibilities of driver's reactions to motion disorders resulting from that emergency condition. Using the PC-Crash software, a vehicle model was designed allowing for simulation of special-purpose vehicle motion. The vehicle model includes a possibility of occurring of sudden tire damage when in motion. In such situation a model of cooperation of a tire and a surface is of crucial significance. A semi-empirical, non-linear TMeasy tire model was used. Its parameters were obtained on the basis of the results of the tests performed on 14.00R20 tires with run flat inserts. A vehicle model parameterization was based on the results of the vehicle measurements, however the validation was based on the results of experimental road tests of braking with damaged tires. Performed calculations and simulations indicated that when braking is started a process of vehicle deviation and related motion track modification is initialized. The motion track deviation increases as the initial braking speed is increased.
Keywords: tire use, special purpose vehicle operation, active safety, tire damage, run flat tires, driver training.Uszkodzenie opony, które dość często pojawia się podczas eksploatacji pojazdów specjalnych (budowlane, leśne, militarne, rolnicze)
IntroductionDifficult conditions of special purpose vehicle operation result in high tire damage risk. The nature of damage varies but it always affects the vehicle traction properties and causes increased driver's effort and driving safety threat. A vehicle with damaged tires (if it is still able to continue a drive, even a short-distance one) has increased motion resistance and it is hard to keep an intended track of motion.The analyses being carried out further on refer to the braking process of a vehicle equipped with run flat tires. The wheels with that type of equipment can be driven for a short distance after tire damage.The goal of this paper is to analyse the beh...
This study analyzed the possibilities to validate the indications of sensors for yaw rate and lateral acceleration within the scope of extended diagnostic routine of the car ESP system at Vehicle Inspection Stations (SKP). The stand tests were performed using the reference sensors and a standard diagnostic tester. The comparison of the yaw rate and lateral acceleration results obtained from the working sensor under examination, recorded with the V box unit, and the results from the reference sensor demonstrated a good conformity both in quality and quantity. But these tests were demonstrated also a pure conformity (both in quality and quantity) with runs obtained from tester. The Root Mean Square (RMS) was used as factor of qualitative estimation. These inconveniences were caused from in sampling frequency incompatibility and lack of recording synchronization for signals from the tester and from reference sensors. The primary importance question is a firmware modification for selected testers. Such a tester should be able to record signals from a reference sensor and have a set sampling frequency for signals from a working sensor. On the basis of already carried out research analyses the suggested frequency should be no fewer than about of 10 Hz. It resulted from a spectral analysis carried out for possessed runs maintaining the Nyquist limit frequency.
Podstawowy wskaźnik kierowalności samochodu, gradient podsterowności, jest wyznaczany na podstawie zależności zmian kąta obrotu kierownicy w funkcji przyspieszenia poprzecznego pojazdu. Członem odpowiedniego wzoru obliczeniowego jest tzw. porównawczy, dynamiczny kąt skrętu koła, w którym, dla pojazdów wieloosiowych, występuje tzw. ekwiwalentny rozstaw osi Le, zastępczego pojazdu dwuosiowego. W pracy przeanalizowano metody wyznaczania tego parametru. Wykorzystano zastępczy, rowerowy model pojazdu, z ekwiwalentnym rozstawem osi Le., do którego można sprowadzić płaski model pojazdu wieloosiowego. Przedstawiono i porównano dwie, analityczne metody obliczeń, które zilustrowano konkretnymi przykładami liczbowymi. Rozważania przedstawione w pracy mogą być wykorzystane do wspomagania obliczeń przy analizie badania kierowalności trzyosiowych i czteroosiowych pojazdów specjalnych, w tym także kołowej Kołowej Platformy Wysokiej Mobilności (KPWM) – prototypowego pojazdu uniwersalnego zastosowania.
One-antenna GPS systems present no possibility for the direct determination of vehicle slip angle. This is an easy task for dual antenna systems; however, many users have this kind of apparatus. In this paper, a method of estimation of this parameter, which is important for the estimation of vehicle steerability factors, is proposed (e.g. TB factor calculated on the basis of data from input test [8]). The method is based on two parameters measured by a one-antenna GPS system; these are the heading angle created from the Doppler channel coming directly from the GPS engine, and the yaw rate measured by an IMU device integrated and cooperating with the GPS engine. The sideslip angle which was calculated according to the proposed method is compared with an equivalent angle calculated on the basis of data from a non-slip measurement of velocity components for selected point of vehicle acquired using. The presented method is illustrated with examples from real tests. In the author’s opinion, the sideslip angle calculated with the application of measurement data obtained from a one-antenna GPS device could be used in practice. From comparison with another upper mentioned method, it follows that the differences between average values of sideslip angles obtained from both considered methods is not greater than 8%.
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