National Repository of Grey Literature 65 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Influence of Powertrain Type on Vehicle Dynamics
Haniška, Jan ; Semela, Marek (referee) ; Bilík, Martin (advisor)
The aim of this master’s thesis is to assess the influence of the vehicle’s powertrain concept on its driving dynamics. The assessment is carried out with the help of data obtained during driving tests done with test vehicles. As a testing cars were choosen 3 Hyundais Kona with different powertrain types, classic internal combustion engine, a hybrid and a purely electric. Performed tests were the so-called moose test, acceleration, deceleration and it was measured center of gravity for all vehicles too. From the data obtained during individual tests, it was subsequently assessed the influence of the vehicle powertrain type on its driving dynamics.
Selected Issues of Motorcyclist's Behavior
Sedláček, Jan ; Bradáč, Albert (referee) ; Semela, Marek (advisor)
This thesis focuses on the braking systems of modern motorcycles. It describes the design details mainly concerning braking systems, ABS, semi-active chassis, but also the MSC stability control system. The experimental part deals with the measurement, analysis of the braking decelerations of motorcycles and evaluation, among others, whether the ABS system reduces the braking distance on dry road. Nine motorcycles were used to measure this issue. All models tested had ABS or the newer ABS system with built-in MSC stability control. Braking progress was analysed from initial speeds of 50 and 70 km/h to a straight-line stop with ABS applied and with ABS deactivated. The results were plotted graphically and can be used to provide information about the actions of the rider and the motorcycle itself. Braking distances, MFDD, initial speeds were calculated. In this study, the video recordings of braking are analyzed and compared with the measured data. The data can be useful for the analysis of single-track vehicle accidents.
Analysis of time demandingness for solution of selected road traffic situations by drivers
Krejčiřík, Roman ; Bucsuházy, Kateřina (referee) ; Semela, Marek (advisor)
The presented diploma thesis deals with the analysis of driver time, which is needed for solving the chosen traffic situation in regular road traffic. The thesis aims to find out the duration, which drivers need for evaluation of chosen various types of intersections, and the duration which is needed to safely drive thru those intersections. Based on the theoretical part of this thesis, the experiment was proposed. This experiment was accomplished by real drive testing. The experiment took place in the city of Brno, with 10 participants. The purpose of the experiment was to obtain the required times for decision-making for 7 different situations in city traffic. Data were collected by eye tracker and afterwards, these data were evaluated and sorted by different categories and factors. The results were compared between the same intersections and also between different intersections. Obtained results give basic information about duration, which is needed for solving the situation. The shortest time obtained was 2,1 s.
Lane change manoeuvre of modern vehicles on wet surface
Mikulec, Roman ; Kropáč, František (referee) ; Mičunek, Tomáš (referee) ; Semela, Marek (advisor)
This dissertation investigates the possibilities of determining the minimal duration of modern vehicles lane change manoeuvre on the wet road surface. In cases when the driver changed lanes or swerved before or during the crash, analysis of this manoeuvre should be carried out, as well as part of a collision avoidance investigation. The issue of lane change has been addressed in several theses in the past, but most of these theses were based on the results of measurements on the dry road surface. It is, therefore, necessary to investigate the applicability of the existing calculation methods to the situation of reduced adhesion conditions, together with the considerable time lag from most of the earlier studies, and therefore the considerable advances in vehicle design and driving stability systems. For this reason, several series of driving tests have been carried out with modern vehicles on predominantly wet road surfaces. These measurements have provided essential input and output variables used to analyse the current calculation methods and determine the set-up of the driving stability systems in simulation programs. Based on the statistical analysis, the so-called Kovařík equation, which has been used so far, was evaluated as the most suitable method for calculating the duration of lane-change manoeuvre, for which a new value of the mathematical constant was found. An alternative calculation of the longitudinal distance travelled by the vehicle in the manoeuvre is also presented in this dissertation.
Selected Driving Manoeuvres of Motorcyclists
Kriegsmann, Luděk ; Bradáč, Albert (referee) ; Semela, Marek (advisor)
The entire diploma thesis is designed into two parts. The first part is focused on the theoretical description of the construction of motorcycles. In particular, the theoretical part deals with the description of the types of motorcycles, types of frames, types of suspension and the description of braking systems used on motorcycles. In the theoretical part, the main parameters of the motorcycle are also addressed, which affect the handling and stability of the motorcycle while riding. The last theoretical part deals with the technique of riding a motorcycle. The second part is focused directly on the execution of the experiment. The experiment consists of measuring five disciplines, namely measuring acceleration, measuring braking deceleration using brakes, measuring deceleration by the engine, measuring exit from an intersection and measuring lateral displacement. Eight motorcycles took part in the measurement. The main outputs from the measurements are time data, deceleration and lateral acceleration values.
Measuring the Driving Manoeuvres of Public Transport Vehicles
Habr, Vojtěch ; Semela, Marek (referee) ; Bilík, Martin (advisor)
Master’s thesis focuses on the the comfort and safety of passengers when using public transport vehicles. The introductory part summarizes previous studies and experiments on a similar topic. It also analyzes the development of night transport in public transport in Brno. The experimental part then describes the methodology and interprets the results of objective measurement of vehicle maneuvers with the XL Meter together with the subjective evaluation by passengers. Based on the outputs of these activities, it determines longitudinal and transverse acceleration limits for a comfortable and safe ride. In addition, emphasis is also placed on comparing the ride thorugh the measuring points during the day and at night. The analysis of the findings compares the results with previously performed experiments.
System analysis of braking truck - trailer combination
Haring, Andrej ; Kubjatko,, Tibor (referee) ; Řehák,, Miloslav (referee) ; Semela, Marek (advisor)
The dissertation deals with the issue of braking of articulated vehicles, especially articulated vehicles consisting of a tractor and a semi-trailer. This configuration was chosen with regard to the number of accidents and their consequences, and often also does not suit the technical condition of the tractor and semi-trailer, which is closely related to the safety of operation of these combinations. In the case of road accidents, the consequences are often very serious, whether it is personal injury or material damage. Investigating these accidents is a relatively demanding process, requiring a high degree of expertise as well as the necessary technical equipment. In contrast to these requirements, the availability of sources from which the necessary information can be drawn is relatively low. The available resources are mostly in a foreign language and are usually solutions to partial problems, not systemically comprehensive literature. Therefore, it is possible to say a "constant demand" for the available professional literature dealing with issues related to the solution of traffic accidents not only of combinations of vehicles, but of commercial vehicles as a whole. From the point of view of the importance, or topicality of needs arising from expert practice, the dissertation is thematically focused on braking of combinations of vehicles. There are several key reasons to focus on articulated vehicles. First of all, this is due to the specific character of the vehicle itself, which consists of two communication-linked brake systems. Other reasons are that the information contained in the dissertation, whether it is descriptive information, assessment of the technical condition of the systems, or the measurement results themselves, can be partially or even fully used for stand-alone towing vehicles or trailers. However, not all problems related to this issue can be solved within the dissertation. Therefore, in the dissertation, significant influences are selected, the solution of which, given the frequency and severity, the author considers essential. From the title of the dissertation it follows that this is a system analysis of the braking of combinations of vehicles. The system concept of solving a problem situation and selected problems are a guarantee that really essential parameters are selected within the content possibilities and scope of the dissertation and the system approach to their solution allows a "general" application in solving similar problems. The aim of the dissertation is a system analysis of the influence of selected parameters on the overall braking effect and stability of commercial vehicle combinations, analysis of input parameters on the decision logic of electronic brake system control unit, where procedures but also conclusions can be applied in similar cases with similar input parameters and decision criteria. Another partial goal is to develop a framework methodology for determining the technical condition of individual components of brake systems of commercial vehicles, which will be possible to apply especially in trucks, where electronically controlled systems are installed. Here, too, a systemic concept is applied, which will enable a wider use of this methodology.
Analysis of Selected Manoeuvres of Bicyclists
Špačková, Kateřina ; Belák, Michal (referee) ; Semela, Marek (advisor)
This diploma thesis Analysis of selected manoeuvres of bicyclists deals with the history and development of the bicycles, further their division of, construction, analysis accident and national legislation in the theoretical part. The practical part of the master thesis is devoted to the measurements of the bicycles. Specifically, it is about acceleration, deceleration, transverse movement, ride in the curve and looking back before changing the direction. For measuring are selected different type of bikes with different construction. The results of individual measurements are evaluated in the end of the diploma thesis.
Determination of duration that driver needs to assess the situation behind the vehicle in course of turning or overtaking manoeuvres.
Belák, Michal ; Rábek,, Vlastimil (referee) ; Kolíbal, Zdeněk (referee) ; Semela, Marek (advisor)
The dissertation thesis deals mainly with determining of the duration that driver needs to assess the situation behind his vehicle at manoeuvers of turning and overtaking, based on the measurements made in real road traffic. These are common and frequent driving manoeuvers, which the driver performs while driving the vehicle in regular road traffic. For their safe execution the driver needs to have sufficient amount of information about the situation around the vehicle and especially behind the vehicle. This information can driver usually gain from devices for indirect vision, most often rear view mirrors. The time thus defined, suitable e.g for the needs of forensic engineering applications for the analysis of road accidents, has not been studied in detail yet. For the purpose of its determination, therefore, an extensive analysis of the current state of problematics related to the indirect vision from the vehicle was carried out. There were formulated influences on the time duration and with this related characteristics of humans as a part of the driver-vehicle-environment system in the thesis. The characteristics of human perception were investigated and the problematics of reaction time was discussed. Existing research focused on the duration of rear view mirrors glances was analyzed and possible methods of its measurement in detail were presented by author. Based on this, an experiment was designed and realized, the time necessary for rear view mirror glances was defined by the author. The results enable to quantify the time that the driver needs for assessing the situation behind the vehicle in connection of turning, overtaking and other driving manoeuvers when the driver needs to change the driving direction. The conclusions showed that the time needed to evaluate the situation behind the vehicle by means of the rear-view mirrors does not normally exceed duration 1 second.
Perception of vehicle speed by pedestrian
Rak, Martin ; Semela, Marek (referee) ; Bilík, Martin (advisor)
This master’s thesis deals with the issue of the perception of speed of a vehicle from pedestrian’s point of view. The theoretical part consists of a research into sense perception of humans and construction of motor vehicles. The practical part designs and describes the experiment which was performed in order to provide data used for analyzing different factors and their effect on the accuracy of vehicle speed estimations.

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