Identification of the Structural Modes of High Performance Bicycles in the Perspective of Wobble Control

2011 ◽  
Author(s):  
Alberto Doria ◽  
Matteo Formentini
Keyword(s):  
Modal Analysis ◽  
Stiffness Matrix ◽  
High Speed ◽  
High Performance ◽  
Point Contact ◽  
Rigid Bodies ◽  
Bicycle Dynamics ◽  
The Road ◽  
On The Road ◽  
Analysis Of Stability

Most of researches in the field of bicycle dynamics deal with auto-stabilization and rider control by means of steer-torque and lean-torque. Bicycle models composed by rigid bodies with thin wheels making point contact with the road and rolling without any slip are suited for carrying out these studies. Numerical analysis of stability by means of these models leads to the capsize, castering and weave modes, which make it possible to understand many aspects of bicycle dynamics. However, some high performance bicycles at high speed show dangerous wobble oscillations. Cyclists’ experience and recent researches highlight that wobble phenomena are related both to tire properties and to fork and frame compliance. Since structural compliance in dynamic conditions generates vibrations, this paper focuses on the study of structural vibrations of high performance bicycles with the modal analysis approach. To isolate the effects of frame and fork compliance, four particular bicycles are considered, they are built assembling a pair of wheels, two forks (fork A and B) with the same shape but different structures and materials and two frames (frame A and B) with the same shape but different structures. Preliminary road tests showed that bicycles made with components A are more prone to wobble oscillations. In order to have a better comprehension of the different influence of fork and frame compliance, first the two forks (with the front wheel) are modally tested with the steer tube locked to a very stiff structure, then, the whole bicycles are tested. Modal analysis is carried out with the impulse method, for the analysis of each bicycle 60 FRFs are measured. The results of modal analysis are presented and the influence of identified modes on bicycle stability is discussed. An important issue of modal analysis of vehicles is the correlation between modal tests carried out in the laboratory and bicycle behavior on the road. When the vehicle is tested in the laboratory, additional constraints are added to guarantee equilibrium, but centrifugal forces are not present, because the vehicle is stationary. Since the analysis of the equations of linearized dynamics shows that the stiffness matrix includes a part due to centrifugal effects, the additional stiffness terms due to constraints in laboratory tests can be assumed to be equivalent to the centrifugal terms of the stiffness matrix at a certain speed. Details and limits of this equivalence are presented and discussed in the paper.

scholarly journals RCVC: RSU-Aided Cluster-Based Vehicular Clouds Architecture for Urban Areas

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 193
Author(s):  
Mohamed Ben bezziane ◽  
Ahmed Korichi ◽  
Chaker Abdelaziz Kerrache ◽  
Mohamed el Amine Fekair
Keyword(s):  
Urban Areas ◽  
High Speed ◽  
Service Discovery ◽  
Cluster Head ◽  
Experimental Comparison ◽  
The Road ◽  
Road Side Unit ◽  
End To End Delay ◽  
End To End ◽  
On The Road

As a promising topic of research, Vehicular Cloud (VC) incorporates cloud computing and ad-hoc vehicular network (VANET). In VC, supplier vehicles provide their services to consumer vehicles in real-time. These services have a significant impact on the applications of internet access, storage and data. Due to the high-speed mobility of vehicles, users in consumer vehicles need a mechanism to discover services in their vicinity. Besides this, quality of service varies from one supplier vehicle to another; thus, consumer vehicles attempt to pick out the most appropriate services. In this paper, we propose a novel protocol named RSU-aided Cluster-based Vehicular Clouds protocol (RCVC), which constructs the VC using the Road Side Unit (RSU) directory and Cluster Head (CH) directory to make the resources of supplier vehicles more visible. While clusters of vehicles that move on the same road form a mobile cloud, the remaining vehicles form a different cloud on the road side unit. Furthermore, the consumption operation is achieved via the service selection method, which is managed by the CHs and RSUs based on a mathematical model to select the best services. Simulation results prove the effectiveness of our protocol in terms of service discovery and end-to-end delay, where we achieved service discovery and end-to-end delay of 3 × 10−3 s and 13 × 10−2 s, respectively. Moreover, we carried out an experimental comparison, revealing that the proposed method outperformed several states of the art protocols.

Lane Detection Algorithm Based on Genetic Algorithm and its Parallel Computing Realization

2012 ◽  
Vol 479-481 ◽  
pp. 65-70
Author(s):  
Xiao Hui Zhang ◽  
Liu Qing ◽  
Mu Li
Keyword(s):  
Genetic Algorithm ◽  
Data Transmission ◽  
High Speed ◽  
High Performance ◽  
Large Data ◽  
Detection Algorithm ◽  
Lane Detection ◽  
The Road ◽  
Time Problem ◽  
High Speed Data

Based on the target detection of alignment template, the paper designs a lane alignment template by using correlation matching method, and combines with genetic algorithm for template stochastic matching and optimization to realize the lane detection. In order to solve the real-time problem of lane detection algorithm based on genetic algorithm, this paper uses the high performance multi-core DSP chip TMS320C6474 as the core, combines with high-speed data transmission technology of Rapid10, realizes the hardware parallel processing of the lane detection algorithm. By Rapid10 bus, the data transmission speed between the DSP and the DSP can reach 3.125Gbps, it basically realizes transmission without delay, and thereby solves the high speed transmission of the large data quantity between processor. The experimental results show that, no matter the calculated lane line, or the running time is better than the single DSP and PC at the parallel C6474 platform. In addition, the road detection is accurate and reliable, and it has good robustness.

Mobile Learning Technologies

2011 ◽  
pp. 146-152 ◽  
Author(s):  
Diane M. Gayeski
Keyword(s):  
Health Care Professionals ◽  
High Speed ◽  
Learning Technologies ◽  
Social Environments ◽  
The Road ◽  
Powerful Learning ◽  
Large Numbers ◽  
On The Road ◽  
And Performance ◽  
Internet Connections

While educational and corporate training environments have made large investments in getting wired to high-speed Internet connections, our work and social environments are rapidly becoming more mobile and flexible. The Internet and organizationally based intranets are powerful learning and performance tools, as long as users have a high-speed connection and up-to-date computing equipment. Online learning and information is not nearly as convenient or reliable when learners need to access sites from their homes, hotel rooms, client locations, or while on the road. In corporate settings, large numbers of critical employees such as factory engineers, health care professionals, builders, and maintenance workers often do not even have offices in which to use a computer.

scholarly journals Accurate whole-night sleep monitoring with dry-contact ear-EEG

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Kaare B. Mikkelsen ◽  
Yousef R. Tabar ◽  
Simon L. Kappel ◽  
Christian B. Christensen ◽  
Hans O. Toft ◽  
...  
Keyword(s):  
High Performance ◽  
Well Being ◽  
Extensive Study ◽  
Sleep Monitoring ◽  
The Road ◽  
Scalp Eeg ◽  
Dry Contact ◽  
Negative Effect ◽  
On The Road

AbstractSleep is a key phenomenon to both understanding, diagnosing and treatment of many illnesses, as well as for studying health and well being in general. Today, the only widely accepted method for clinically monitoring sleep is the polysomnography (PSG), which is, however, both expensive to perform and influences the sleep. This has led to investigations into light weight electroencephalography (EEG) alternatives. However, there has been a substantial performance gap between proposed alternatives and PSG. Here we show results from an extensive study of 80 full night recordings of healthy participants wearing both PSG equipment and ear-EEG. We obtain automatic sleep scoring with an accuracy close to that achieved by manual scoring of scalp EEG (the current gold standard), using only ear-EEG as input, attaining an average Cohen’s kappa of 0.73. In addition, this high performance is present for all 20 subjects. Finally, 19/20 subjects found that the ear-EEG had little to no negative effect on their sleep, and subjects were generally able to apply the equipment without supervision. This finding marks a turning point on the road to clinical long term sleep monitoring: the question should no longer be whether ear-EEG could ever be used for clinical home sleep monitoring, but rather when it will be.

Analysis of Dynamic Load Level of High-Speed Heavy Vehicle Imposed on Uneven Pavement

2011 ◽  
Vol 138-139 ◽  
pp. 146-152
Author(s):  
Guo He Guo ◽  
Yu Feng Bai ◽  
Tao Wang
Keyword(s):  
Dynamic Load ◽  
High Speed ◽  
Load Level ◽  
Heavy Vehicle ◽  
Vehicle Speed ◽  
Destructive Effect ◽  
The Road ◽  
Wide Range ◽  
On The Road ◽  
Factor Interaction

Based on the significant destructive effect of heavy vehicle on uneven roads, two simplified models of pavement unevenness and vehicle dynamic load were established in accordance with D'A lembert principle, and Matlab software was used to analyze the changing law of dynamic load under the conditions of different road unevenness, vehicle speed and load. The results show that vehicles running on uneven road may produce more cumulative damages than static load, and DLC (dynamic load coefficient) changes in wide range, maximum up to 2.0 or more; the effect of speed and load on dynamic load is complex, and due to multi-factor interaction, DLC doesn’t consistently increase or decrease with speed and load increasing. Although the dynamic load level caused by high-speed heavy vehicle is not necessarily too high, its impact on the road can not be ignored.

scholarly journals Incremental, Critical Plane Analysis of Standing Wave Development, Self-Heating, and Fatigue during Regulatory High-Speed Tire Testing Protocols

2020 ◽  
Author(s):  
William V. Mars ◽  
Govind Paudel ◽  
Jesse D. Suter ◽  
Christopher G. Robertson
Keyword(s):  
Steady State ◽  
High Speed ◽  
Structural Integrity ◽  
Loss Modulus ◽  
Standing Waves ◽  
Strength Properties ◽  
Critical Plane ◽  
The Road ◽  
Self Heating ◽  
On The Road

ABSTRACT Tire speed ratings derive from regulatory testing in which tire structural integrity is validated over a series of steps with successively increasing speed. For the FMVSS 139 high-speed standard, there are four half-hour duration speed steps at 80, 140, 150, and 160 kph. Speed ratings from Q through Y may be attained through the UN ECE R30 regulation high-speed testing. For either protocol, a tire must demonstrate the ability to operate without crack development at high speed for a specified period. After the test, “there shall be no evidence of tread, sidewall, ply, cord, inner liner, belt or bead separation, chunking, broken cords, cracking, or open splices.” A workflow for simulating regulatory high-speed durability performance has been developed based upon (1) recent improvements to the Abaqus steady-state transport formulation that now permit converged solutions to be obtained at high speed (including after the development of standing waves in the tire) and (2) Endurica DT self-heating and incremental fatigue simulations that account for thermal effects and for damage accumulation occurring due to a schedule of load cases. The self-heating calculation features the Kraus model and accurately captures viscoelastic loss modulus dependence on strain amplitude and temperature. For each step of the high-speed procedure, steady-state structural and thermal solutions are first computed. The deformation history in the presence of standing waves is shown to require rainflow counting due to the occurrence of multiple load cycles per tire revolution. Crack growth is finally integrated for each potential critical plane through each step of the test until failure is indicated. Standing waves at high speed induce significant self-heating and damage, rapidly limiting high-speed performance. The temperature dependence of self-heating and strength properties also plays a major role in limiting high-speed durability. The simulations were executed on both a flat surface and on the regulation specified 1.7 m diameter road wheel. As expected, durability testing on the road wheel is more severe, and the beneficial effect of a nylon overwrap is predicted.

scholarly journals Vibration modeling of a vehicle equipped with MR damper and aerodynamic elements

2019 ◽  
Vol 20 (1-2) ◽  
pp. 57-61
Author(s):  
Wiesław Grzesikiewicz ◽  
Michał Makowski
Keyword(s):  
High Speed ◽  
Mr Damper ◽  
Road Surface ◽  
Vehicle Model ◽  
Numerical Investigations ◽  
The Road ◽  
Mr Dampers ◽  
On The Road ◽  
Magneto Rheological ◽  
Vibration Modeling

We considered of a vehicle model equipped with controlled magneto-rheological (MR) dampers and controlled aerodynamic elements. The vibrations of the vehicle moving at high speed during acceleration and braking are analysed. The purpose of this analysis is to determine the effect of forces generated on aerodynamic elements on vehicle vibrations and changes in wheel pressure on the road surface during acceleration and braking. The presented work presents the results of numerical investigations obtained on the basis of the developed vehicle model.

The first traffic accidents involving cars in Kharkiv in the early twentieth century (based on materials from the local press)

2020 ◽  
Keyword(s):  
Twentieth Century ◽  
Urban Space ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Road Accidents ◽  
The Road ◽  
Road Users ◽  
Early Twentieth Century ◽  
Car Accidents ◽  
On The Road

Research aim is to establish the history of the first road accidents involving cars in Kharkiv in the early twentieth century. Research methodology. The article discusses the road accidents involving cars as one of the aspects of the emergence and development of new vehicles and ways of communication "traffic" in Kharkov in the early twentieth century from the point of view of the concept of modernization of urban space. Scientific novelty. For the first time in the historiography the history ofthe road accidents involving cars in Kharkov in the early twentieth century was the subject of special research. The publications from the newspapers «Yuzhnyj Kraj» («South Land») and «Utro» («Morning») newspapers revealed a number of testimonies of the first car accidents involving cars in Kharkiv in the early 20th century. The typical causes, circumstances, course and consequences of such incidents are established. Conclusions. It was found that the first car accidents were caused primarily by the unusualness of the new vehicle for traditional road users in time pedestrians, carriages and, especially, horses, which frightened the unusual view and high speed of automatic crews, the roar of their previous engines, known as time of movement of smoke and smoke, loud exhausts, internal combustion engines and various horns and even «sirens». Factors such as the poor quality of driver training and / or the irresponsibility of individual drivers when driving on city streets also played an important role in some cases. The most known example of dangerous behavior on the road was the case of a nobleman O. L. Samoilov (owner and driver of the infamous newspaper «Red Car»), who regularly consciously ensures the safety of road users. This has led to frequent road accidents involving schoolchildren of varying severity from other road users  people, animals (horses, dogs) and vehicles. At the same place on carriages and features of pedestrians who are accustomed to traffic on city streets. For a long time, they did not report the changes caused by the appearance of dozens of cars on the streets of Kharkiv and neglected their own safety, behaving carelessly.

Wireless Networks for Vehicular Support

2011 ◽  
pp. 4135-4140 ◽  
Author(s):  
Pietro Manzoni ◽  
Carlos T. Calafate ◽  
Juan-Carlos Cano ◽  
Antonio Skarmeta ◽  
Vittoria Gianuzzi
Keyword(s):  
Ad Hoc Networks ◽  
High Speed ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Building Blocks ◽  
The Road ◽  
V2v Communication ◽  
Safety Message ◽  
On The Road ◽  
Hoc Networks

Vehicular Ad hoc NETworks (VANETs) is an area under intensive research that promises to improve security on the road by developing an intelligent transport system (ITS). The main purpose is to create an inter-communication network among vehicles, as well as between vehicles and the supporting infrastructure. The system pretends to offer drivers data concerning other nearby vehicles, especially those within sight. The problem of information sharing among vehicles and between the vehicle and the infrastructure is another critical aspect. A general communication infrastructure is required for the notification, storage, management, and provision of context-aware information about user travel. Ideally an integrated vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication paradigm enriched with an information management system would solve the problem. The infrastructure should manage all the collected safety events garnered from vehicles and the interesting information to be provided to the user, which is adapted to the car context and driver preferences. Finally, security issues should be considered. Since the information conveyed over a vehicular network may affect critical decisions, fail-safe security is a necessity. The first directive for any V2V communication scheme is, therefore, that every safety message must be authenticated. Because of the high speed and therefore short duration within which communication between two cars is possible, communication must be non-interactive, and message overhead must be very low. The urgency of safety messages implies that authentication must be instantaneous without additional communication. Moreover, providing strong security in vehicular networks raises important privacy concerns that must also be considered. Safety messages include data that is dangerous to the personal privacy of vehicle owners. Most relevant is the danger of tracking a vehicle through positional information. A set of security basics to address these challenges should be proposed that can be used as the building blocks of secure applications. In this article we will focus on the aforementioned technologies and engineering issues related to vehicular ad-hoc networks, emphasizing the challenges that must be overcome to accomplish the desired vehicular safety infrastructure.

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