Academic literature on the topic 'Motorcycle`s dynamics'

The main objectives of the work described are to devise an effective path-based motorcycle simulation capability and to add to understanding of how riders control motorcycles. Optimal linear preview control theory was previously applied to the tracking of a roadway by a car, using a simple car model operating in fixed control. Similar theory is applied to path control of motorcycles. The simple car previously employed is replaced by a much more elaborate motorcycle. The steering angle control used previously is changed into steering torque control. Rider upper body lean torque is also allowed as a control input. The machine speed is considered constant but is a parameter of the motion. The objective of the optimal control is to minimize a weighted sum of tracking errors, rider lean angle and control power. The time-invariant optimal control corresponding to a white noise disturbance and to an infinite optimization horizon is found for many situations, involving variations in machine speed and performance priorities. Tight controls, corresponding to high weightings on performance, and loose controls, corresponding to high weightings on control power, are identified. Results show the expected pattern for preview control, that information well into the future is of limited value in determining the present control inputs. Full system performance is achievable with only finite preview. The extent of the preview necessary for full performance is determined as a function of machine speed and performance priorities. This necessary preview is found to be in accord with conventional wisdom of motorcycle riding and rider training. Optimal path tracking preview controls are shown to represent the inverse dynamics of the motorcycle. New light is shed on the relative effectiveness of steering torque and body lean torque controls. Simulations of an optimally controlled motorcycle and rider combination are conducted. A typical lane change path and an S-shaped path from the literature are used. For a chosen speed, optimal controls are installed on the machine for which they were derived and simulation results showing tracking performance, control inputs, and other responses are included. Transformation of the problem from a global description, in which the optimal control is found, to a local description corresponding to the rider’s view, is described. It is concluded that a motorcycle rider model representing a useful combination of steering control capability and computational economy has been established. The model yields new insights into rider and motorcycle behavior.

Abstract: A motorcycle helmet is the best protective headgear for the prevention of head injuries due to direct cranial impact. A finite element model based on realistic geometric features of a motorcycle helmet is established, and explicit finite element code is employed to simulate dynamic responses at different impact velocities. Peak acceleration and Head injury criterion values derived from the head form are used to assess the protective performance of the helmet. We have concluded that the dynamic responses of the helmet dramatically vary with impact velocity, as well as the mechanical properties of the outer shell and energy- absorbing liner. At low velocities e.g. 8.3 m/s, the shell stiffness and liner density should be relatively low to diminish head- contact force. At high velocity e.g. 11m/s, a stiffer shell and denser liner offer superior protection against head injuries. Different tests were performed in ansys explicit dynamics solver by taking different materials and calculating PLA, Head Injury Criteria, K.E, P.E, contact energy etc. The results obtained for different materials were then compared with easy other to draw the necessary conclusion’s. Keywords: Peak Linear Acceleration (PLA), Head Injury Criteria.

A study of the effects of regular road undulations on the dynamics of a cornering motorcycle is presented. This work is based on an enhanced version of the motorcycle model described in “A Motorcycle Model for Stability and Control Analysis” (R. S. Sharp and D. J. N. Limebeer, 2001, Multibody Syst. Dyn., Vol. 6, No. 2, pp. 123–142). We make use of root-locus and frequency response plots that were derived from a linearized version of this model; the linearization is for small perturbations from a general steady-cornering equilibrium state. The root-locus plots provide information about the damping and resonant frequencies of the key motorcycle modes at different machine speeds, while the frequency response plots are used to study the propagation of road forcing signals to the motorcycle steering system. Our results are based on the assumption that there is road forcing associated with both wheels and that there is a time delay between the front and rear wheel forcing signals—this is sometimes referred to as wheelbase filtering. As has been explained before, control systems are used in the nonlinear simulation code to establish and maintain the machine’s speed and roll angle at preset values (for flat road running). These controllers are used to find the machine’s equilibrium state and not to emulate a rider’s control actions. The results show that at various critical cornering conditions, regular road undulations of a particular wavelength can cause severe steering oscillations. At low speeds the machine is susceptible to road forcing signals that excite the lightly damped wobble and front suspension pitch modes. At higher speeds it is the weave and front wheel hop modes that become vulnerable to road forcing. We believe that the results and theory presented here explain many of the stability related road accidents that have been reported in the popular literature and are therefore of practical import. The models used in this research make use of the multibody modelling package AUTOSIM (Autosim 2.5+ Reference Manual, 1998, Mechanical Simulation Corporation) and are available at the web site http://www.ee.ic.ac.uk/control/motorcycles/. The motorcycle and tire parameters can be found at the end of the code.

AbstractThis paper investigates the effect of separated exhaust expansion chamber parameters on pressure oscillations in spark-ignited internal combustion (IC) gasoline engines. It is known that exhaust expansion chambers are becoming increasingly more popular among both – original equipment (OE) and aftermarket equipment (AE) exhaust system manufacturers for performance-oriented motorcycles equipped with mainly single cylinder engines, but the companies are reluctant to reveal any detailed principles of operation of the mentioned expansion chambers. The subject of this research is the type of expansion chamber (separate) as used on performance-oriented motorcycles, particularly its’ effect on exhaust pressure pulsations as different chamber volumes, locations and passage sizes are tested. Time-dependent computational fluid dynamics (CFD) analysis was carried out in Solidworks Flow Simulation environment on a simplified exhaust header pipe model imitating engine operation at full load and steady speed. Honda CRF450R motorcycle engine was used as the example and fully defined using a 1D engine performance calculator software to determine the combustion chamber pressure and exhaust valve lift at any given crankshaft position. Volume flow rate of exhaust gasses at the header pipe inlet was calculated based on engine parameters and operating speed. The average pressure values with respect to physical time were measured and graphed across the header pipe inlet cross-section. Eight different header pipe and exhaust expansion chamber combinations were modelled, tested, and results compared at low, medium and high engine speeds. It was found that the presence of exhaust expansion chamber tends to dampen the amplitude and decrease the frequency of pressure oscillations generated at the opening of the exhaust valve(s). Observations show that the addition of an expansion chamber as per design of performance-oriented motorcycles helps to decrease the negative effect of engine tuning while also dampening the positive effect.

Background: During the first Austrian MotoGP Grand Prix of 2020, following a serious accident involving the riders J. Zarco and F. Morbidelli, Morbidelli’s riderless bike cartwheeled across turn 3, narrowly missing V. Rossi and M. Viñales by just a few centimeters. As is the case with ordinary traffic accidents, analyzing the dynamics of motorcycle racing accidents can help improve safety; however, to date, the literature lacks studies that analyze the causes and severity of such accidents. Hence, the purpose of this study was to analyze the main causes that led to the accident at the 2020 Austrian MotoGp Grand Prix, to quantify the speeds and distances of the bikes and riders involved, and to hypothesize several alternative scenarios using a low-cost method. Method: Kinovea and Google Earth Pro software were used to identify markers along the racetrack and to measure the distances and calculate the time it took the motorcycles to cover those distances. The analyses were carried out on three 30-fps (frames per second) videos. Results: Zarco’s average speed as he was overtaking Morbidelli on the straightaway before turn 2 was 302 ± 1.8 km/h, higher than that of Rins and Rossi (299.7 ± 1.7 and 296 ± 1.7 km/h, respectively). The speed of Zarco and Rossi’s bikes 44.5 m before the crash was the same (267 ± 7.9 km/h). Immediately after overtaking Morbidelli, Zarco moved 2.92 m towards the center of the racetrack from point A to B, crossing Morbidelli’s trajectory and triggering the accident. Morbidelli’s riderless bike flew across turn 3 at a speed of about 76 km/h, missing V. Rossi by just 20 cm. The consequences could have been catastrophic if Rossi had not braked just 0.42 s before encountering Morbidelli’s bike in turn 3. Conclusion: Through a low-cost quali-quantitative analysis, the present study helps us to gain a deeper understanding of the dynamics of the accident and its main causes. Furthermore, in light of our findings regarding the dynamics and severity of the accident and the particular layout of the Red Bull Ring circuit, racers should be aware that overtaking at the end of turn 2, following the same trajectory as the riders involved in the crash, could be very risky.

A composite material is a combination of two or more chemically distinct and insoluble phases; its properties and structural performance are superior to those of the constituents acting independently. MMCs are made by dispersing a reinforcing material into a metal matrix to improve their properties. They are prepared by powder metallurgy and casting, although several technical challenges exist with casting technology. Achieving a homogeneous distribution of reinforcement within the matrix is one such challenge, and this affects directly on the properties and quality of composite. In this work a composite is developed by adding Mango seed shell Ash (MSSA) particulate in Al- Si-Mg Alloy by mass ratio 5%, 10%, 15% and 20%. The composite was prepared by stir casting technique. It is proposed to use this material for production of motorcycle wheel hub which are subjected to continuous wear as the hubs are in direct contact with the brakes and rotating sprockets. The MSSA, was characterized using X- ray fluorescent (XRF). The result reveals SiO2, has the highest percentage composition followed by CaO, Al2O3, Fe2O3 and Mg2O as major phases. The presents of these hard constituent compounds suggests that the mango seed shell ash can be used as particulate reinforcement in various metal matrices since the chemical composition has similarity with the XRF analysis of Periwinkle shell ash, rice husk, fly ash, and bagasse ash currently used in metal matrix composite. Mechanical tests such as hardness test and impact test were conducted. The results revealed that increase in the percentage of MSSA progressively increased the hardness of the material from 5% wt to a maximum hardness of 43.2 HV at 15% addition of MSSA. This represents a 26.16% improvement over the unreinforced alloy. However, the impact energy progressively decreases of the material from 5%wt of MSSA and later increased to optimum energy at 15% addition of MSSA. From the results it is concluded that composite material such as Al- Si-Mg/ MSSA is one of the options as a material for production of motorcycle hub. The wear test of the composite was then carried out using Taguchi design to optimize the range of MSSA from 5% wt -15% wt., Sliding speed of 5cm/s -20cm/s, sliding distance from 50m to 200m, and the load of 2N, 4N, 6N, & 8N respectively. Analysis of the result of SN ratio for wear rate shows the optimum wear resistant value is in the combination of Load=4N, sliding speed = 10cm/s sliding distance=200m and MSSA=15 wt% These also correspond with the analysis of wear maps & wear rate presented in the diagrams of dynamic friction coefficient (COF) for Al-Si- Mg/ MSSA Composite.

Purpose The purpose of this paper is to highlight that the need for improved system identification methods within the domain of modal analysis increases under the impulse of the broadening field of applications, e.g., damage detection and vibro-acoustics, and the increased complexity of today’s structures. Although significant research efforts during the last two decades have resulted in an extensive number of parametric identification algorithms, most of them are certainly not directly applicable for modal parameter extraction. So, based on this, the aim of the present work is to develop a technique for modal parameter extraction from the measured signal. Design/methodology/approach A survey and classification of the different modal analysis methods are made; however, the focus of this thesis is placed on modal parameter extraction from measured time signal. Some of the methods are examined in detail, including both single-degree-of-freedom and multi-degree-of-freedom approaches using single and global frequency-response analysis concepts. The theory behind each of these various analysis methods is presented in depth, together with the development of computer programs, theoretical and experimental examples and discussion, in order to evaluate the capabilities of those methods. The problem of identifying properties of structures that possess close modes is treated in particular detail, as this is a difficult situation to handle and yet a very common one in many structures. It is essential to obtain a good model for the behavior of the structure in order to pursue various applications of experimental modal analysis (EMA), namely: updating of finite element models, structural modification, subsystem-coupling and calculation of real modes from complex modes, to name a few. This last topic is particularly important for the validation of finite element models, and for this reason, a number of different methods to calculate real modes from complex modes are presented and discussed in this paper. Findings In this paper, Modal parameters like mode shapes and natural frequencies are extracted using an FFT analyzer and with the help of ARTeMiS, and subsequently, an algorithm has been developed based on frequency domain decomposition (FDD) technique to check the accuracy of the results as obtained from ARTeMiS. It is observed that the frequency domain-based algorithm shows good agreement with the extracted results. Hence the following conclusion may be drawn: among several frequency domain-based algorithms for modal parameter extraction, the FDD technique is more reliable and it shows a very good agreement with the experimental results. Research limitations/implications In the case of extraction techniques using measured data in the frequency domain, it is reported that the model using derivatives of modal parameters performed better in many situations. Lack of accurate and repeatable dynamic response measurements on complex structures in a real-life situation is a challenging problem to analyze exact modal parameters. Practical implications During the last two decades, there has been a growing interest in the domain of modal analysis. Evolved from a simple technique for troubleshooting, modal analysis has become an established technique to analyze the dynamical behavior of complex mechanical structures. Important examples are found in the automotive (cars, trucks, motorcycles), railway, maritime, aerospace (aircrafts, satellites, space shuttle), civil (bridges, buildings, offshore platforms) and heavy equipment industry. Social implications Presently structural health monitoring has become a significantly important issue in the area of structural engineering particularly in the context of safety and future usefulness of a structure. A lot of research is being carried out in this area incorporating the modern sophisticated instrumentations and efficient numerical techniques. The dynamic approach is mostly employed to detect structural damage, due to its inherent advantage of having global and location-independent responses. EMA has been attempted by many researchers in a controlled laboratory environment. However, measuring input excitation force(s) seems to be very expensive and difficult for the health assessment of an existing real-life structure. So Ambient Vibration Analysis is a good alternative to overcome those difficulties associated with the measurement of input excitation force. Originality/value Three single bay two storey frame structure has been chosen for the experiment. The frame has been divided into six small elements. An algorithm has been developed to determine the natural frequency of those frame structures of which one is undamaged and the rest two damages in single element and double element, respectively. The experimental results from ARTeMIS and from developed algorithm have been compared to verify the effectiveness of the developed algorithm. Modal parameters like mode shapes and natural frequencies are extracted using an FFT analyzer and with the help of ARTeMiS, and subsequently, an algorithm has been programmed in MATLAB based on the FDD technique to check the accuracy of the results as obtained from ARTeMiS. Using singular value decomposition, the power Spectral density function matrix is decomposed using the MATLAB program. It is observed that the frequency domain-based algorithm shows good consistency with the extracted results.

AbstractCycling races contain a multitude of motorcycles for various activities including television broadcasting. During parts of the race, these motorcycles can ride in close proximity of cyclists. Earlier studies focused on the impact of a nearby motorcycle on cyclist drag for in-line arrangements. It was shown that not only a motorcycle in front of a cyclist but also a motorcycle closely behind a cyclist can substantially reduce cyclist drag. However, there appears to be no information in the scientific literature about the impact of the motorcycle on cyclist drag for parallel and staggered arrangements. This paper presents wind tunnel measurements of cyclist drag for 32 different parallel and staggered cyclist-motorcycle arrangements. It is shown that the parallel arrangement leads to a drag increase for the cyclist, in the range of 5 to about 10% for a lateral distance of 2 to 1 m. The staggered arrangement can lead to either a drag increase or a drag decrease, where the latter is about 2% for most positions analyzed. For one of the parallel arrangements, computational fluid dynamics simulations were performed to provide insight into the reasons for the drag increase. A cyclist power model was used to convert the drag changes into potential time gains or losses. Compared to a lone cyclist riding at a speed of 46.8 km/h (13 m/s) on level road in calm weather, the time loss by a drag increase of 10%, 4% and − 2% was 2.16, 0.76 s and − 0.80 s per km, respectively. These time differences are large enough to influence the outcome of cycling races.

AbstractMotorcycles are present in cycling races for reasons including television broadcasting. During parts of the race, these motorcycles ride in front of individual or groups of cyclists. Concerns have been expressed in the professional cycling community that these motorcycles can provide aerodynamic benefits in terms of drag reduction for the cyclists drafting behind them. However, to the best of our knowledge, no information about the extent of these benefits is present in the scientific literature. Therefore, this paper analyses the potential drag reduction for a cyclist by drafting behind a motorcycle. Wind tunnel measurements and numerical simulations with computational fluid dynamics were performed. It was shown that drafting at separation distances d = 2.64, 10, 30 and 50 m can reduce the drag of the cyclist down to 52, 77, 88 and 93% of that of an isolated cyclist, respectively. A cyclist power model is used to convert these drag reductions into potential time gains. For a non-drafting cyclist at a speed of 54 km/h on level road in calm weather, the time gains by drafting at d = 2.64, 10, 30 and 50 m are 12.7, 5.4, 2.7 and 1.6 s per km, respectively. These time differences can influence the outcome of cycling races. The current rules of the International Cycling Union do not prevent these aerodynamic benefits from occurring in races.

The significant problems in metropolitan’s traffic are road congestion and safety  The Intelligent Transportation Systems (ITS) offer improvement for the problems using Roadside Unit placement along the road to detect and inform all matters relating to traffic condition. This research will be conducted measurement interconnection network that will be used by Roadside Unit (RSU) to communicate with the central office. RSU will transmit data type of vehicle and speed information to the central office server. Measurements carried out on the existing cellular network and find the right position for placement of RSU according network availability by considering the received signal power, pathloss and performance data delivery. Measurement locations in the main road metropolitan city of Surabaya by using sensors (counted mode) as the RSU. From the measurements taken showed that communication between infrastructures managed by using digital sensors falcon plus II with a percentage error of less than 3%. Communications between the RSU and the central office using GPRS / GSM network supported by the presence of a nearby BTS tower. The power level of BTS antenna greater than  wireless modem (SIM 900) sensitivity (-107 dbm), with pathloss exponent about 2.77. The ability of data transmission by wireless modem (SIM 900) reached 85.6 Kbps to 42.8 Kbps for downlink and uplink. The server side using the internet network 512 Mbps with a dynamic public IP features that support port forwarding that is useful for data communication. Best sensor position for mounting the sensor horizontally at a height of 40-120 cm from ground level to the maximum detection distance of 150 m for vertical mounting above the overpass. Best sensor position facing the one lane road with a height of 5-6 m from ground level, with the best angle measurement is 45˚-60˚ for vertical and horizontal mounting. Average speed of vehicles is 38.34 km / h with a volume of 4128 units of vehicles, mostly motorcycles and traffic density 135 units / km. Keywords— Roadside unit, I2I, ITS, cellular network

This Master’s thesis deals with designing a measuring device that would record driver’s movements during dynamic riding states known as localization, and based on the recorded data creating a simulation in multi-body software. The first part reviews the current state of knowledge in the field of photogrammetry, sensors, and motorcycles’ characteristics. Moreover, the second part focuses on constructing the measuring device, practical aspects of data collection, processing, and evaluation in multi-body software.