Master of Science / Rubber is a widely used material globally and undergoes significant changes as it ages. However, the specific consequences of rubber aging on tires and vehicle dynamics remain a relatively underexplored domain. This study delves into the effects of rubber aging on tires and motorcycle dynamics. A Dynamical Mechanical Analysis (DMA) test was performed to study the effect of rubber aging combined with computer simulation models to predict how much the rubber wears out over time. It was found that as rubber gets older it doesn't wear out much faster. This might be because the changes in the rubber properties as it ages are very small. The rubber material also gets stiffer as it ages, leading to minimal differences in the wear rate. The Magic Formula (MF) model was used in this study to model motorcycle tires. A 3-4% increase in the longitudinal and lateral tire forces was observed as the tire aged. This was followed by simulations to study the motorcycle behavior during straight-line and turning motion. It was found that the front tires of the motorcycle had an approximately 3% change in the forces experienced, while the forces experienced by the rear tires only changed by 1-2% with respect to aging. These results are similar to the results obtained by other researchers on the effects of rubber aging on car performance. Thus, this study stresses the importance of understanding how tires change over time and how that affects how motorcycles perform.

Motorradfahrer gehören zu den am meisten gefährdeten Verkehrsteilnehmern im Straßenverkehr. Häufig ist die Unfallursache ein Kontrollverlust auf Landstraßen, der durch Ausnutzung des physikalischen Potenzials in Form von größeren Schräglagenwinkeln vermieden werden könnte. Gleichzeitig sind in der Realität gefahrene Schräglagen über eine größere Gruppe von Fahrern und eine längere Strecke unbekannt, was vor allem auf die erforderliche spezielle Messtechnik zurückzuführen ist. Der Schwerpunkt liegt daher auf der Entwicklung eines kostengünstigen Messverfahrens zur Messung der Schräglagenwinkel von Motorrädern. Smartphones zeichnen sich in der Regel durch integrierte Inertialsensoren aus, die für die Erfassung der Fahrdynamik von Motorrädern geeignet sind. Mit Hilfe einer auf die Anforderungen zugeschnittenen Smartphone-App zur Erfassung von Messdaten auf dem Motorrad werden die Daten der Sensoren aufgezeichnet. Anschließend werden mittels einer Offline-Auswertung die Drehwinkel zwischen dem Smartphone und dem Motorrad-Koordinatensystem bestimmt, die inertialen Messdaten transformiert und der Schräglagenwinkel berechnet. Ein wesentlicher Bestandteil ist die Validierung der entwickelten Messkette durch einen Vergleich der Ergebnisse mit einem hochpräzisen Messsystem. Dieser wurde auf verschiedenen Strecken zur Bestimmung der Datenqualität durchgeführt. Als Machbarkeitsstudie diente eine Probandenstudie, die die Praxistauglichkeit der Messkette bestätigte. Die Studienergebnisse werden zusätzlich auszugsweise dargestellt und diskutiert. Die erfolgreiche Validierung auf verschiedenen Strecken, die Praxistauglichkeit der Datenerfassung und die Genauigkeit des Messsystems ermutigen dazu, die Smartphone-App auf ein größeres Panel von Testpersonen auszurollen und damit Daten über ein größeres Fahrerkollektiv zu erheben.:Introduction, State of Research, Methods, Measurement Chain Verification, Results and Discussion, Conclusion / Motorcyclists are among the most vulnerable road users in road traffic. Often, the cause of accidents is a loss of control on rural roads which could be averted by making use of the physical potential in terms of larger lean angles. At the same time, in reality driven lean angles over a larger group of riders and a longer route are unknown which is mainly due to the special measuring technology required. The focus is therefore on the development of a low-cost measurement method for measuring the lean angles of motorcycles. Smartphones are usually characterized by integrated inertial sensors, which are suitable for the acquisition of motorcycle driving dynamics. Employing a smartphone app tailored to the requirements for collecting measurement data on the motorcycle, the data of the sensors are recorded. During the offline evaluation, the rotation angles between the smartphone and the motorcycle coordinate system are determined, the inertial measurement data are transformed and the roll angle is calculated. An essential part is the alignment of the developed measurement chain with a high-precision measurement system. This was carried out on different routes and thus the data quality was determined. As a feasibility study, a test person study with several participants was carried out, which confirmed the practical suitability of the measurement chain. Hence, the study outcomes are briefly shown and discussed. The successful validation on different routes, the practical suitability of the data acquisition and the accuracy of the measurement system encourage to roll out the smartphone app to a larger panel of test persons and thus to collect data on a larger driver collective.:Introduction, State of Research, Methods, Measurement Chain Verification, Results and Discussion, Conclusion

Off-road and racing motorcycles require a particular setup of the suspension to improve the comfort and the safety of the rider. Further, due to ground unevenness, off-road motorcycle suspensions usually experience extreme and erratic excursions in performing their function. In this regard, the adoption of nonlinear devices, such as progressive springs and hydro pneumatic shock absorbers, can help limiting both the acceleration experienced by the sprung mass and the excursions of the suspensions. For dynamic analysis purposes, this option involves the solution of the nonlinear differential equations that govern the motion of the motorcycle, which is excited by the stochastic road ground profile. In this study a 4 degrees-of-freedom (4-DOF) nonlinear motorcycle model is considered. The model involves suspension elements with asymmetric behaviour. Further, it is assumed that the motorcycle is exposed to loading of a stochastic nature as it moves with a specified speed over a road profile defined by a particular power spectrum. It is shown that a meaningful analysis of the motorcycle response can be conducted by using the technique of statistical linearization. The validity of the proposed approach is established by comparison with results from pertinent Monte Carlo studies. In this context the applicability of auto-regressive (AR) filters for efficient implementation of the Monte Carlo simulation is pointed out. The advantages of these methods for the synthesis of excitation signals from a given power spectrum, are shown by comparison with other methods. It is shown that the statistical linearization method allows the analysis of multi-degree-of-freedom (M-DOF) systems that present strong nonlinearities, exceeding other nonlinear analysis methods in both accuracy and applicability. It is expected that the proposed approaches, can be used for a variety of parameter/ride quality studies and as preliminary design tool by the motorcycle industry.

[pt] Veículos autônomos são um problema recente, com aplicação em carros e motocicletas ainda nos estágios iniciais. Além das dificuldades inerentes de fazer um veículo mover-se independentemente, a motocicleta autônoma deve permanecer estável em qualquer velocidade e trajetória. O objetivo principal deste trabalho é desenvolver uma motocicleta elétrica autônoma com sistema de instrumentação de baixo custo. Para tanto, foi analisado um modelo dinâmico de motocicleta, capaz de reproduzir o comportamento real e permitindo a implementação de estratégias de controle linear em tempo real. O controlador tem dois objetivos diferentes: manter a motocicleta estável e seguir uma trajetória desejada, de forma autônoma. Experimentos foram realizados com a motocicleta de escala reduzida com o objetivo de caracterizar seus elementos; as estratégias de controle propostas foram simuladas com o modelo dinâmico ajustado. Por fim, os algoritmos de controle são aplicados ao sistema real através de uma plataforma atuada capaz de reproduzir a dinâmica de veículos de duas rodas. O presente trabalho é uma ferramenta para o ensino de engenharia, envolvendo estudantes de diferentes níveis em torno de um problema complexo. O sistema permite uma aprendizagem contínua com dificuldade crescente, envolvendo temas como dinâmica de multicorpos; análise de resultados através de simulações de software; eletrônica e filtros na instrumentação embutida e técnicas de controle para manter o sistema estável em todos os caminhos desejados, culminando na aplicação experimental dos conceitos citados. / [en] Autonomous vehicles are an interesting and recent problem, with its application in cars and motorcycles still in its early stages. In addition to the inherent difficulties in making a vehicle move independently, the autonomous motorcycle has to be able to remain stable at any speed and trajectory. The vehicle s stability can be achieved by different solutions and control techniques. The main objective of this work is to develop an autonomous electric motorcycle with low cost sensing system. For this, a dynamic model of two-wheeled vehicles is analyzed, capable of describing the dynamic behavior while being simple enough to allow the implementation of real-time linear control strategies. The controller has two different objectives: to maintain the motorcycle stable and to follow a desired trajectory, in an autonomous way. Experiments were carried out with the small scale motorcycle aiming to characterize its elements for the theoretical model; then the proposed control strategies were simulated with the adjusted dynamic model. Finally, the control algorithms are applied to the real system through an actuated platform capable of reproducing the dynamic behavior of single-track vehicles. At last, the present work is a tool for teaching engineering, involving multilevel students around a complex, but familiar, problem. The system allows for continuous learning with increasing difficulty, involving multibody dynamics, experimental results analysis via software simulations, electronics and filters present in the embedded instrumentation and many control techniques to keep the system stable in every desired path, culminating in the experimental application of cited concepts.

Two and three-wheeled vehicles are being used in increasing numbers in many emerging countries. The dynamics of such vehicles are very different from those of cars and other means of transportation. This thesis deals with a study of the dynamics of a motorcycle and an extensively used three-wheeled vehicle, called an “auto-rickshaw” in India. The commercially available multi-body dynamics (MBD) software, ADAMS, is used to model both the vehicles and simulations are performed to obtain insight into their dynamics. In the first part of the thesis, a study of the two wheeler dynamics is presented. A fairly detailed model of a light motorcycle with all the main sub-systems, such as the frame, front fork, shock absorbers , power train, brakes, front and rear wheel including tire slips and the rider is created in ADAMS-Motorcycle. The simulation results dealing with steering torques and angles for steady turns on a circular path are presented. From the simulation results and analytical models, it is shown that for path radius much greater than motorcycle wheel base, the steering torque and angle can be described by only two functions for each of the two variables. The first function is related to the lateral acceleration and can be determined numerically and the second function, in terms of the inverse of the path radius, is derived as an analytical approximation. Various tire and geometric parameters are varied in the ADAMS simulations and it is clearly shown that steady circular motion of a motorcycle can be reasonably approximated by only two curves–one for steering torque and one for steering angle. In the second part of the thesis, a stability analysis of the three-wheeled “autorickshaw” is presented. The steering instability is one of the major problems of the “auto-rickshaw” and this is studied using a MBD model created in ADAMS-CAR .In an Initial model the frame ,steering column and rear-forks (trailing arms) are assumed to be rigid. A linear eigenvalue analysis, at different speeds, reveals a predominantly steering oscillation, called a “wobble” mode, with a frequency in the range of 5 to 6Hz. The analysis results show that the damping of this mode is small but positive up to the maximum speed(14m/s) of the three-wheeled vehicle. Experiments performed on the three-wheeled vehicle show that the mode is unstable at speeds below 8.33m/s and thus the experimental results do not agree with the model. Next, this wobble instability is studied with an analytical model, similar to the model proposed for wheel shimmy problem in aircrafts. The results of this model show that the wobble is stable at low speeds regardless of the magnitude of torsional stiffness of steering column. This is also not matching with the experimental result. A more refined MBD model with flexibility incorporated in the frame, steering column and the trailing arm is constructed. Simulation results with the refined model show three modes of steering oscillations. Two of these are found to be well damped and the third is found to be lightly damped with negative damping at low speeds, and the results of the model with the flexibility is shown to be matching reasonably well with the experimental results. Detailed simulations with flexibility of each body incorporated, one at a time, show that the flexibility in the steering column is the main contributor of the steering instability and the instability is similar to the wheel shimmy problem in aircrafts. Finally, studies of modal interaction on steering instabilities and parametric studies with payload and trail are presented.