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1

Conception of suspension system with variable stiffness for mobile robots

Duda Sławomir, Gembalczyk Grzegorz, Kowalik Zygmunt, Machoczek Tomasz

Vibrations in Physical Systems

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2024

|

Vol. 35, nr 1

art. no. 2024118

EN

The paper presents the results of work on an innovative form of the suspension node. It is a concept of semi-active suspension that allows for control the stiffness system during operation of the device. This type of suspension can be used in robotic intralogistics systems, where mobile platforms must have a suspension that ensures adequate vibration damping, keeps the platform in a horizontal position, and at the same time provides adequate pressure to the ground of the drive wheels. A particularly interesting object with the potential possibility of using such a suspension are vehicles with omnidirectional wheels. The proposed design form is the first prototype version, which should primarily be used to validate computational models. The idea of the developed suspension element refers to the double torsion shafts.

2

Analysis of the effectiveness of changes introduced to the suspension system of the Scorpio 7 Martian rover

Bernat Rafał, Lorek Bartłomiej, Kosobudzki Mariusz

Journal of TransLogistics

|

2023

|

Vol. 19

19-30

EN

The paper describes an innovative solution for the suspension system of the Scorpio 7 Martian rover, developed based on the previous generation of the vehicle - Scorpio X. The machine was intended to participate in Martian rover competitions from the Rover Challenge series. The document presents an analysis of the parameters characterising the discussed suspension system, with heavy emphasis on the mass of the platform, deflection under working conditions, amount of space required and angular positions of paramount components. Those characteristics are compared to values describing the systems of Scorpio X.

3

Analiza budowy i działania układu zawieszenia łazika Scorpio X

Lorek Bartłomiej, Bernat Rafał, Kosobudzki Mariusz

Journal of TransLogistics

|

2022

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Vol. 8, nr 1

61-72

PL

W artykule przedstawiono charakterystykę konstrukcji układu zawieszenia zależnego pojazdu wysokiej mobilności Scorpio X, skonstruowanego na potrzeby uczestniczenia w zawodach łazików marsjańskich serii Rover Challenge. Przedstawiono i omówiono podstawowe wymagania regulaminowe zawodów oraz koncepcję zawieszenia pojazdu. Analizy ograniczono do wybranych warunków ruchu pojazdu, tj. pokonywania pojedynczej przeszkody terenowej. Wyznaczono przełożenie kinematyczne w przyjętym układzie zawieszenia oraz poddano analizie wartości sił, jakie oddziałują na elementy zawieszenia. Obliczono wartości odkształceń elementów zawieszenia i ramy pojazdu. Przedstawiono również wnioski z użytkowania pojazdu i wymagane zmiany jakie należy wprowadzić do kolejnej wersji pojazdu.

EN

The article presents the characteristics of the structure of the dependent suspension system of the Scorpio X high-mobility vehicle, constructed for the purpose of participating in the competition of Mars rovers of the Rover Challenge series. The basic regulatory requirements of the competition and the concept of the vehicle suspension were presented and discussed. The analyses were limited to selected vehicle motion conditions, i.e. negotiating a single terrain obstacle. The kinematic ratio in the adopted suspension system was determined, and the values of forces that affect the suspension elements were analyzed. The deformation values of the suspension elements and the vehicle frame were calculated. The conclusions from the use of the vehicle and the required changes to be made to the next version of the vehicle were also presented.

4

Investigations on an influence of the material properties on vibrations of active rocker-bogie suspension

Sokół Krzysztof, Pierzgalski Maciej

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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Vol. 70, nr 1

art. no. e138239

EN

Unmanned vehicles are often used in everyday life, mostly by rescue teams or scientists exploring new terrains. In those constructions, the suspension has constant dimensions, which leads to many disadvantages and limits the application area. The solution to these problems can be creating a six-wheeled mobile platform that can dynamically change the wheelbase in relation to the area of action or terrain inclination angle. The active change in location of the center of gravity gives a possibility to access sloppy obstacles not available with classical suspensions. The main scope of this study is to investigate the influence of material properties on vibration frequency at different lengths of suspension members. The obtained results will allow finding the optimum material for producing a prototype unit.

5

The method of estimating kinematic road excitation with use of real suspension responses and model

Klockiewicz Zbyszko, Ślaski Grzegorz

Vibrations in Physical Systems

|

2019

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Vol. 30, nr 2

art. no. 2019214

EN

The paper deals with the problem of vertical kinematic excitations in road vehicle dynamics simulation, with the main focus on reconstruction of random excitations using measured dynamic responses of a car suspension. The possibility of causing excitations adequately in terms of chosen conditions of exploitation and in reliable way is crucial to properly asses ride comfort, ride safety as well as rattle space and fatigue strength of suspension elements. The paper presents a method of generating equivalent kinematic excitation allowing for reconstruction of suspension dynamic responses in simulation. The method uses unsprung mass accelerations acquired during test rides and a model of vertical suspension dynamics. The method uses estimated displacements of unsprung mass as a preliminary approximation of kinematic excitation and tracking control system with a PID controller, which causes corrections of kinematic excitations transforming it to the form that allows for faithful reconstruction of unsprung mass accelerations and, in turn, kinematic excitations. The paper presents the basic structure of kinematic excitations’ reconstruction system as well as a method of tuning PID controller’s coefficients so that the error in estimation is minimized. Research and verification of results were done using a sine chirp signal and constant frequency sine waves. The similarity of estimated road profiles is high with error no larger than 8% of the original signal’s amplitude.

6

Simulation study of the method of random kinematic road excitation’s reconstruction based on suspension dynamic responses with signal disruptions

Klockiewicz Zbyszko, Ślaski Grzegorz, Spadło Mikołaj

Vibrations in Physical Systems

|

2019

|

Vol. 30, nr 2

art. no. 2019208

EN

The paper presents the results of simulation studies of the method of random kinematic road excitation’s reconstruction based on the dynamic responses of the suspension acquired in road tests. The method uses registered unsprung mass accelerations as well as model of suspension’s vertical dynamics and tracking control with PID controller to monitor unsprung mass accelerations’ signal in simulation. In the simulation the quality of reconstruction of random irregularities of the road profile was tested. The road profiles were generated based on their power spectral density of road profile heights that is in line with the description given in ISO 8608 standard. Four road classes had their profiles estimations tested – A, B, C and D (corresponding to highways through city roads to the very bad quality roads). The influence of the simulated noise in the suspension’s dynamic response signal – i.e. unsprung mass acceleration – was also tested. The methods of processing of the initial acceleration’s signal from the road tests were proposed and achieved accuracy was defined. Lastly, the necessary requirements to use the method effectively were defined and its limitations were listed.

7

Seat suspension system of the electric golf cart

Jírová R., Svoboda R., Pešík L.

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2018

|

z. 99

89--94

EN

The paper deals with reducing vibrations transmitted from electric golf cart wheels to the seat and the seated person. These vibrations appear while driving a golf cart on uneven terrain of a golf course. This problem can be solved by using the elastic and damping link between the cart frame and seat, which is tightly connected to the electric power battery. A mathematical calculation is used to evaluate the designed solution in which the golf cart is defined as a system of masses connected with elastic and damping links. The result of the designed solution’s mathematical description provides a reference step response of the golf cart seat.

8

Analysis of transverse stability parameters of hybrid buses with active trailers

Sakhno V., Poliakov V., Murovanyi I., Selezniov V., Vovk Y.

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2018

|

z. 101

185--201

EN

The objective of the article is to determine the transverse stability indexes of hinge-connected buses (HCBs) by applying the computation-analytical method. The transverse stability parameters of hybrid buses with active trailers are analysed. Based on these parameters (the angles of the roll and redistribution of loads on the sides), the analytical dependences are developed. The dependences describe the movement of the parts of HCBs in the vertical plane. Considering the action of longitudinal and transverse forces, the roll angles of the bus and the trailer were determined. The limiting angle of the side roll of the bus rollover was found to be γамах = 27.560γмах, and the trailer rollover to be γамах = 30.210. The obtained transverse stability indexes of HCBs with a hybrid power plant testify to the compliance with the standard DSTU UN/ECE R 111-00.

9

The influence of vehicle preparation on the results of suspension kinematics measurement

Wach K.

Technical Transactions

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2018

|

Vol. 115, iss. 8

199--209

EN

This paper concerns the assessment of the impact of tyre pressure and additional vehicle loading which is inconsistent with the manufacturer’s requirements on the results of wheel alignment measurement. A sample of results from tests performed on a second generation Toyota Prius and a fifth generation Volkswagen Passat are presented. The tested vehicles differed in the types of front axle wheel suspension. An analysis of the obtained results was conducted. The analysis revealed differences between the results of reference tests performed in accordance with the requirements of vehicle manufacturers and those conducted for incorrectly prepared vehicles. The values of these differences depended, inter alia, on the type of suspension.

PL

Praca dotyczy oceny wpływu ciśnienia w ogumieniu oraz obciążenia pojazdu niezgodnego z wymaganiami producenta, na wyniki pomiaru geometrii zawieszenia. Przedstawione zostały przykładowe wyniki prób przeprowadzonych na samochodach Toyota Prius II generacji oraz Volkswagen Passat generacji piątej. Pojazdy różniły się rodzajami zawieszenia kół osi przedniej. Wykonana została analiza uzyskanych wyników, która wskazała różnice pomiędzy wynikami prób referencyjnych – przeprowadzonych zgodnie z wymaganiami producentów – a próbami dla pojazdów niewłaściwie obciążonych bądź z niewłaściwym ciśnieniem w ogumieniu. Wartości tych różnic uzależnione były między innymi od rodzaju zawieszenia.

10

Measurements of the angular and linear displacements of steered wheel

Wach K.

Technical Transactions

|

2018

|

Vol. 115, iss. 2

219--227

EN

This paper concerns the use of a prototype measuring instrument for conducting measurements of the linear and angular displacements of a steered wheel in relation to the car body. The theoretical principles of the measurement are presented, as are the notation method and a solution to the system of equations of the geometric constraints of the instrument’s mechanism. In the research section, the manner in which the measurements were conducted is discussed and sample results are described. A preliminary analysis of the results is performed in the summary section.

PL

Praca dotyczy pomiarów przemieszczenia i orientacji koła kierowanego względem nadwozia pojazdu wykonanych za pomocą prototypowego przyrządu pomiarowego. Przedstawione zostały teoretyczne podstawy pomiaru, jak również sposób zapisu i rozwiązywania układu równań więzów geometrycznych mechanizmu przedmiotowego przyrządu. W części badawczej omówiono sposób przeprowadzania pomiarów oraz przedstawiono przykładowe wyniki. W podsumowaniu została dokonana ich wstępna ocena i analiza.

11

Vibration analysis and control of locomotive system

Shireesha Y., Venkata Suresh B., Sateesh B.

Mechanics and Mechanical Engineering

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2018

|

Vol. 22, nr 1

195--205

EN

Vibration is an undesirable phenomenon of ground vehicles like locomotives and vibration control of vehicle suspension system is an active subject of research. The main aim of the present work is to modeling and analysis of locomotive system. The simplified equations for dynamical locomotive are firstly established. Then the dynamical nature of the locomotive without control is investigated, and also active control suspension and passive control suspension are compare and discussed. The obtained simulation shows that suspension of the locomotive with feedback control could decrease the locomotive vibration. According to the above control strategy along with angular acceleration it also reduces the possibility of vibration of the locomotive body, to improves the stability of vehicle operation.

12

Thermal conductivity of CNT - wated nanofluids: a review

Akhilesh M., Santarao K., Babu M. V. S.

Mechanics and Mechanical Engineering

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2018

|

Vol. 22, nr 1

207--220

EN

In heat transportation applications, water is most commonly used fluid. The efficiency of equipment used in these applications depends on thermal characteristics of water used. The thermal characteristics of water could be upgraded by suspending high thermal conducting solid nanoparticles. In this paper an attempt has been made to know how the use of surfactants and functionalization of carbon nanotube walls can affect the thermal characteristics and stability of nanofluid. A thorough analysis of collected literature revealed that carbon nanotubes have much higher thermal conductivity than any other nanoparticles and hence improve the thermal properties of water when suspended in them. Further it is concluded that suspension of carbon nanotubes in water requires use of surfactant or functionalization of carbon nanotube walls with proper group. By setting optimum pH and better dispersion, better thermal conductivity is possible. Experimental studies in the literature survey reveal that chemical stabilization techniques and physical stabilization techniques together decide the stability of the nanofluid.

13

Investigation of forced frequency in a commercial vehicle suspension system

Kumar S. D., Kumar S. S., Kumar K. A.

Mechanics and Mechanical Engineering

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2018

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Vol. 22, nr 4

967--974

EN

Vehicle suspension plays a vital role in maintaining the center of gravity to achieve perfect balancing of the vehicle to provide the comfortable ride. While designing the suspension system of automobile, vibration is the main aspect to be considered. This paper aims to analyze the automobile front and rear suspension for a four wheeler using analytical and numerical approach. Existing details of the suspension is collected using the concept of reverse engineering. Natural and forced frequency of the front and rear suspension system is calculated theoretically based on the collected data's. The natural frequency and forced frequency is numerically computed for front and rear suspension. The amplitude of vibration is reduced by replacing the spring material and its forced frequency is reduced by 1.18% and 1.56% for front and rear suspension system respectively. This result reveals that low carbon steel has ability to reduce the forcing frequency and can produce comfort ride.

14

Zawieszenie działalności gospodarczej w zakresie transportu drogowego

Dylong A.

Logistyka

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2018

|

nr 5

42--43

PL

Przewoźnik drogowy ma prawo zawiesić w całości bądź w części wykonywanie transportu drogowego na okres nie dłuższy niż 12 miesięcy (art. 14a ust. 1 ustawy z dnia 6 września 2001 r. o transporcie drogowym, t. j. Dz. U. z 2017 r., poz. 2200 z późn. zm., dalej ‘u.t.d.’). Przyczyna zawieszenia nie ma znaczenia i nie jest badana przez właściwy organ. Istotne jest natomiast to, że w ciągu 14 dni od dnia, w którym przewoźnik zawiesił swoją działalność, zobowiązany jest zawiadomić organ, który udzielił licencji o zawieszeniu wykonywania transportu drogowego.

15

Analysis of vehicle’s suspension’s dynamic responses during test track rides and real exploitation

Klockiewicz Z., Ślaski G.

Journal of Mechanical and Transport Engineering

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2018

|

Vol. 70, No. 3

25--40

EN

The following paper presents a study of dynamic responses of a passenger vehicle in typical exploitation conditions. It describes the process of acquiring data from the test rides and their further analysis using statistical values using MatLab. The analysis focuses on accelerations of sprung and unsprung mass, suspension deflection and its speed, comparing the values achieved on different road surfaces, taking into account safety limits and suspension characteristic. The data acquired are presented as graphs of density of probability and cumulative empirical probability, as well as tables listing dynamic responses undergoing analysis. The results allow for estimation of expected dynamic responses of a vehicle, thus making the preparation of future experiments more thorough.

PL

Niniejszy artykuł opisuje badania odpowiedzi dynamicznych zawieszenia samochodu osobowego w typowych warunkach eksploatacyjnych. Zaprezentowano w nim sposób pozyskania danych z jazd testowych i ich dalszej analizy statystycznej w programie Mat-Lab. Analiza skupia się na przyspieszeniach masy resorowanej i nieresorowanej, ugięciu zawieszenia i jego prędkości, porównując wartości otrzymane na różnych typach nawierzchni z uwzględnieniem typowych ograniczeń prędkości na danym typie drogi i charakterystykę zawieszenia. Zebrane dane ukazane są w formie wykresów gęstości prawdopodobieństwa i skumulowanej częstości oraz tabel opisujących analizowane odpowiedzi dynamiczne. Wyniki pozwalają na określenie przybliżonych wartości odpowiedzi dynamicznych, tym samym ułatwiając przygotowanie przyszłych badań.

16

Analiza zmodyfikowanej konstrukcji mechanizmu kolumny Macphersona

Kwietniewski M., Bil T.

Autobusy : technika, eksploatacja, systemy transportowe

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2018

|

R. 19, nr 11

41--44

PL

Nazwa kolumna MacPhersona, pochodzi od nazwiska wynalazcy tego rozwiązania Earle’a S. MacPhersona, która po raz pierwszy została wyprodukowana w fabryce Forda w 1949 roku. Jest to jedno z najczęściej używanych typów zawieszenia przedniego z kołami kierowanymi w popularnych samochodach osobowych. Zaletą tego typu zawieszenia jest zwarta konstrukcja, wadą natomiast jest m.in. wpływ ruchu amortyzacji na położenie koła kierowanego mogące powodować niezamierzoną zmianę kierunku jazdy. Jednocześnie przy ruchu „resorowania” następuje niewielkie dodatkowe pochylenie kół. W proponowanym rozwiązaniu zaproponowano częściową eliminację tego typu niepoprawności poprzez zmianę rodzaju połączenia końcówki drążków kierowniczych z kołami kierowanym pojazdu. Wprowadzona zmiana polega na zastąpieniu jednego z przegubów kulistych występujących w tego typu połączeniach na dwa przeguby obrotowe. Zmiana taka wprowadza do modelu matematycznego opisującego zachowanie się zawieszenia pod wpływem ruchu amortyzacji dodatkowych parametrów. Odpowiedni dobór tych parametrów pozwala na znaczne zmniejszenie niepotrzebnych zmian kierunku w trakcie jazdy. Opisany model konstrukcji mechanizmu pozwala na analizę wpływu wszystkich jego wymiarów na wybrane parametry zachowania się kół w trakcie jazdy, wynikające z ruchów resorowania i kierowania.

EN

The McPherson strut name comes from the inventor of this Earle S. MacPherson solution, which was first manufactured at the Ford plant in 1949. This is one of the most commonly used types of front suspension in popular passenger cars. The advantage of this type of suspension is a compact construction, but the disadvantage is. The influence of the damping motion on the position of the steering wheel may result in an unintentional change of direction of travel. At the same time, there is a slight additional tilt of the wheels when the „spring” movement. In the proposed solution, partial elimination of this type of incorrectness is proposed by changing the type of connection of the steering rod end to the steering wheels of the vehicle. The introduced change consists in replacing one of the spherical joints in these joints into two rotary joints. Such a change introduces a mathematical model describing the behavior of the suspension under the influence of the depreciation of additional parameters. Proper selection of these parameters allows for significant reduction of unnecessary direction changes during driving. The described model of the structure of the mechanism allows to analyze the influence of all its dimensions on the selected parameters of the behavior of the wheels during the ride, resulting from the movement of the suspension and steering.

17

Numerical analysis on the influence of suspended equipment on the ride comfort in railway vehicles

Dumitriu M.

Archive of Mechanical Engineering

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2018

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Vol. LXV, nr 4

477--496

EN

To study the impact of suspended equipment on the ride comfort in a railway vehicle, a rigid flexible general model of such a vehicle is required. The numerical simulations is based on two different models, derived from the general model of the vehicle, namely a reference model of a vehicle with no equipment, and another model with six suspended elements of equipment mounted in various positions along the carbody. The objective of this paper arises from the observation that the literature does not contain any study that highlights the change in the ride comfort resulting exclusively due to the influence of equipment. The influence of the suspended equipment on the ride comfort is determined by comparing the ride comfort indices calculated in the carbody reference points, at the centre and above the two bogies, for a model with six elements of equipment and a model of the vehicle with no equipment.

18

Solution approaches to differential equations of mechanical system dynamics: a case study of car suspension system

Terefe Tesfaye O., Lemu Hirpa G

Advances in Science and Technology. Research Journal

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2018

|

Vol. 12, no. 2

266--273

EN

Solution of a dynamic system is commonly demanding when analytical approaches are used. In order to solve numerically, describing the motion dynamics using differential equations is becoming indispensable. In this article, Newton’s second law of motion is used to derive the equation of motion the governing equation of the dynamic system. A quarter model of the suspension system of a car is used as a case and sinusoidal road profile input was considered for modeling. The state space representation was used to reduce the second order differential equation of the dynamic system of suspension model to the first order differential equation. Among the available numerical methods to solve differential equations, Euler method has been employed and the differential equation is coded MATLAB. The numerical result of the second degree of freedom, quarter suspension system demonstrated that the approach of using numerical solution to a differential equation of dynamic system is suitable to easily simulate and visualize the system performance.

19

The influence of vehicle body roll angle on the motion stability and maneuverability of the vehicle

Parczewski K., Wnęk H.

Combustion Engines

|

2017

|

R. 56, nr 1

133--139

EN

The article discusses the impact of design solutions of vehicle suspensions into angles of body roll. It was shown which type of suspensions is better from this point of view. There were examined the dependence of the suspensions parameters on the vehicle body roll angle. The influence of camber angle on the force transmitted to the tire contact with the road surface was analysed. The lateral forces were measured on the test stand. There was tested dependency of lateral forces from the sideslip angle for different angles of camber. Was analysed change of lateral forces generated by camber angle on the vehicle which was made on a scale ~ 1:5 during tests carried out on the testing track. For this purpose, two tests have been selected: first one allowing the measurement in steady motion conditions, the second one with dynamic change of direction of vehicle motion. The graphs show the effect of camber angles on the controllability and stability of the vehicle motion.

20

Analysis of the force during overcoming the roadblock – the preliminary experimental tests

Polasik J., Waluś K.

Transport Problems

|

2016

|

T. 11, z. 1

113--120

EN

The paper applies to the issue of preservation of passenger vehicles during overcoming the roadblocks on a dry asphalt surface with the constant speed. The study aimed to estimate the forces which are affecting the suspension of the vehicle during the contact between a tyre and roadblock. Using the video recording it is possible to calculate the values of the tyre deflection and forces acting in the system. The obtained deflections of the tyres were compared to earlier laboratory test results and load deflection characteristics of the tyres with the same size. The roadblock with the defined geometry causes a dynamic deflection of the tyre. During the study a significant change in the geometry of the suspension has not occurred. The paper presents the characteristics of the vehicles research with a particular regard to model and type of tyres. The determination of the exact dimensions of the roadblocks and application of the ADIS16385 system for acquisition and archiving the features of the kinematic motion of the vehicle allowed to determine the speed at the moment of collision with the roadblock.

PL

Praca dotyczy problematyki zachowania pojazdów osobowych podczas pokonywania przeszkody stałej na suchej nawierzchni asfaltowej, z zadaną prędkością. Przeprowadzone badania miały na celu oszacowanie sił oddziałujących na zawieszenie pojazdu w momencie styku opony z przeszkodą. Wykorzystując nagranie wideo, możliwe były obliczenie proporcji ugięcia opony oraz teoretyczne wyznaczenie sił działających w układzie. Otrzymaną wartość ugięcia opony porównano z wcześniejszymi wynikami badań laboratoryjnych i charakterystykami obciążenie-ugięcie dla opon o tym samym rozmiarze. Przeszkoda o zdefiniowanej geometrii powodowała ugięcie dynamiczne opony. Podczas badań nie zaobserwowano istotnej zmiany geometrii zawieszenia. W artykule przedstawiono charakterystyki pojazdów badawczych, ze szczególnym uwzględnieniem modeli i rodzaju/typu opon. Opisano dokładne wymiary przeszkody, a wykorzystany układ ADIS 16385 do akwizycji i archiwizacji cech kinematyczny ruchu pojazdu umożliwił określenie prędkości w chwili najechania na przeszkodę.