Bicycle Type Research Articles

Wobble of a racing bicycle with a rider hands on and hands off the handlebar

So far fundamental papers on the understanding of the wobble mode at motorcycles have been published, but in contrast, little research has been published on the wobble mode at bicycles. Wobble denotes a characteristic unstable oscillatory mode dominated by oscillations of the front wheel about the steering axis. The wobble mode of a trekking bicycle at low speeds has already been analysed, where no influence of the rider's hands on the steering system is taken into account. The wobble mode of a racing bicycle at higher speeds has not been addressed in more detail so far. The paper points out the difference between a trekking bicycle and a racing bicycle in particular with respect to the wobble mode. Different geometry, mass and stiffness properties of both types of bicycles and different characteristic positions of the rider are considered. As the wobble at racing bicycles often occurs at high speeds, when riding down a grade with hands on a dropped handlebar, a passive rider model, that takes into account the movement of the rider's arms, is presented.

Measurement and Analysis System for Bicycle Field Test Studies

The work presented describes the development of a measurement and analysis system for bicycle field test studies capable of measuring structural responses including strain and acceleration. The system incorporates 24 sensors measuring strain, 4 sensors measuring acceleration, a stand-alone data acquisition unit weighing 1.7kg which can be mounted behind the seat post and an offline programme analysing the data obtained. The system has been fully implemented on a BMX bicycle for the work presented herein. Piezo-electric accelerometers and resistance strain gauges are used as sensors which are wired to the data acquisition (DAQ) unit. The DAQ unit consists of a controller-chassis, 4 signal conditioning modules and specific application software. The software which controls the measurement process performs sensor calibration, simultaneous 24 bit data acquisition with a sampling frequency of 1000Hz, signal conditioning and data storage. The sampling frequency was established as optimal in specifically designed assessment tests. The data is post-processed to determine the frequency responses, maximum accelerations and strains and to illustrate the time behaviour of accelerations and strains. The measurement and analysis system is validated in common cycling scenarios and a race simulation on a race track. The system is applicable to different types of bicycles and enables comprehensive investigations of structural phenomena.

The Effect of Crosswinds on Cyclists: An Experimental Study

The aims of this research were to firstly investigate the effect of crosswinds on the aerodynamic behaviour of cyclists and secondly, to determine which parameters (cyclist position and bike type) influenced the aerodynamic forces on cyclists the most. The aerodynamic response of two different full-scale bikes with and without a mannequin has been recorded for a variety of crosswind angles ranging from 0o – 90o (in 15o increments). The results showed that the wind induced force is a function of the crosswind angle. The actual aerodynamic loads arising from such winds can be up to about 2.5 times the aerodynamic drag. It has also been observed that the torso angle has little effect on the lateral force coefficient. In contrast, the bike type significantly affects the aerodynamic forces: at large yaw angles, a road bike is responsible for approximately 60% of the total lateral force coefficient. This study is the first step in the process of determining the effect of crosswind from a full range of angles of attack on cyclists, and will help to improve the safety of cyclists and equipment, and to define guidelines for cycling lanes.

미소운동 변환을 이용한 자율주행 자전거의 기구학 모델

This paper presents a new method of kinematic modeling for autonomous bicycle by using the differential motion transformation. Kinematic model is indispensable to trajectory planning and control for an autonomous mobile robot. The conventional methods of kinematic modeling for an autonomous bicycle depend on intuition by geometry. On the contrary, the proposed method in this paper is based on the systematic differential motion transformation, thus applicable to various types of autonomous bicycles. The differential motion transformation gives Jacobian between two coordinate frames and the velocity kinematics as a result.

이동 로봇 위치 추정 및 시뮬레이션 프로그래밍 툴킷

본 논문은 실제 환경과 모의실험에서 이동 로봇의 위치 추정과 자율주행 구현을 위한 프로그래밍 툴킷에 대해 서술한다. 기존에 사용되고 있는 라이브러리들은 복잡성과 유용성의 결함으로 사용에 어려움이 있다. 제안된 툴킷은 추측항법, 운동 모델, 측정 모델, 그리고 방향 또는 지향각의 연산을 위한 툴킷들로 구성된다. 추측 항법과 운동 모델은 차륜 구동 로봇과 전, 후륜 속도에 의한 이륜차 로봇에 대해 다룬다. 툴킷들은 실제 환경과 모의실험에서의 자율주행을 위해 사용 가능하다. 툴킷의 사용가능성은 모의실험의 결과와 실제 실험의 결과를 보임으로써 증명한다. 제안된 툴킷은 이동 로봇의 위치추정, 지도 작성, 그리고 장애물 회피와 같은 자율주행의 구성 기술을 위한 알고리즘의 검사에 사용할 수 있을 것으로 기대된다. This paper reports a programming toolkit for implementing localization and navigation of a mobile robot both in real world and simulation. Many of the previous function libraries are difficult to use because of their complexity or lack of usability. The proposed toolkit consist of functions for dead reckoning, motion model, measurement model, and operations on directions or heading angles. The dead reckoning and motion model deals with differential drive robot and bicycle type robot driven by front wheel or rear wheel. The functions can be used for navigation in both real environment and simulation. To prove the feasibility of the toolkit, simulation results are shown along with the results in real environment. It is expected the proposed toolkit is used for test of algorithms for mobile robot navigation such as localization, map building, and obstacle avoidance.

Modeling of Passing Events in Mixed Bicycle Traffic with Cellular Automata

The primary objective of this study was to use the cellular automata (CA) method to model the characteristics of bicycle passing events in mixed bicycle traffic on separated bicycle paths. The mixed traffic was composed of two types of bicycles: the conventional bicycle (c-bicycle) and the electric bicycle (e-bicycle). The number of passing events and the characteristics of mixed bicycle traffic were investigated in the field on eight physically separated bicycle paths in China. Then a CA model was calibrated with the use of the field data to simulate the passing events in the mixed bicycle traffic. The results showed that the CA model could simulate the features of bicycle passing events well. The simulation results were consistent with field observations. An increase in the ratio of e-bicycles would not significantly increase the number of passing events, but e-bicycles did contribute substantially to passing events in mixed bicycle traffic. E-bicycles were shown to have more stability than c-bicycles, especially in traffic with a high flow rate. The findings of this study could improve the performance of simulation techniques to reflect the actual characteristics of mixed bicycle traffic.

North America's First E-Bikeshare

The integration of electric bicycles (e-bikes) with bikesharing could increase the utility of bikesharing through a reduction of some barriers to bicycling and an increase in the number of prospective users. North America's first e-bikesharing system (cycleUshare) at the University of Tennessee, Knoxville, offers a new, sustainable transportation option for students, faculty, and staff. The cycleUshare system with two stations was launched as a small pilot project to study the technology and its users' experiences. This paper presents an overview of the cycleUshare system and reports experiences from the first year of operation. With 93 enrolled users, cycleUshare provided a unique opportunity to study not only the system's use but how individual users made trips with both regular bicycles and e-bikes and the factors that influenced those trips. The study reported here found that only 22% of users accounted for 81% of the trips. Factors of speed and convenience played major roles in participants' decisions to use the system, and speed and comfort were the most influential factors in the selection of an e-bike rather than a regular bicycle. Most of the reported trips were class related, although e-bikes were used for a wide variety of trip purposes. Walking was the mode most displaced by the system; this result indicated that e-bikesharing expanded user mobility. User perceptions about bicycle types were explored also. This model of e-bikeshare was effective in its capability to attract users to both regular bicycles and e-bikes and to expand user mobility.

Personal and trip characteristics associated with safety equipment use by injured adult bicyclists: a cross-sectional study

BackgroundThe aim of this study was to estimate use of helmets, lights, and visible clothing among cyclists and to examine trip and personal characteristics associated with their use.MethodsUsing data from a study of transportation infrastructure and injuries to 690 adult cyclists in Toronto and Vancouver, Canada, we examined the proportion who used bike lights, conspicuous clothing on the torso, and helmets on their injury trip. Multiple logistic regression was used to examine associations between personal and trip characteristics and each type of safety equipment.ResultsBike lights were the least frequently used (20% of all trips) although they were used on 77% of trips at night. Conspicuous clothing (white, yellow, orange, red) was worn on 33% of trips. Helmets were used on 69% of trips, 76% in Vancouver where adult helmet use is required by law and 59% in Toronto where it is not. Factors positively associated with bike light use included night, dawn and dusk trips, poor weather conditions, weekday trips, male sex, and helmet use. Factors positively associated with conspicuous clothing use included good weather conditions, older age, and more frequent cycling. Factors positively associated with helmet use included bike light use, longer trip distances, hybrid bike type, not using alcohol in the 6 hours prior to the trip, female sex, older age, higher income, and higher education.ConclusionsIn two of Canada’s largest cities, helmets were the most widely used safety equipment. Measures to increase use of visibility aids on both daytime and night-time cycling trips may help prevent crashes.

Prevalence of Bicycle Helmet Use by Users of Public Bikeshare Programs

Public bikeshare programs are becoming increasingly common in the United States and around the world. These programs make bicycles accessible for hourly rental to the general public. We seek to describe the prevalence of helmet use among adult users of bikeshare programs and users of personal bicycles in 2 cities with recently introduced bikeshare programs (Boston, MA, and Washington, DC). We performed a prospective observational study of adult bicyclists in Boston, MA, and Washington, DC. Trained observers collected data during various times of the day and days of the week. Observers recorded the sex of the bicycle operator, type of bicycle, and helmet use. All bicycles that passed a single stationary location in any direction for a period of between 30 and 90 minutes were recorded. There were 43 observation periods in 2 cities at 36 locations; 3,073 bicyclists were observed. There were 562 (18.3%; 95% confidence interval [CI] 16.4% to 20.3%) bicyclists riding shared bicycles. Overall, 54.5% of riders were unhelmeted (95% CI 52.7% to 56.3%), although helmet use varied significantly with sex, day of use, and type of bicycle. Bikeshare users were unhelmeted at a higher rate compared with users of personal bicycles (80.8% versus 48.6%; 95% CI 77.3% to 83.8% versus 46.7% to 50.6%). Logistic regression, controlling for type of bicycle, sex, day of week, and city, demonstrated that bikeshare users had higher odds of riding unhelmeted (odds ratio [OR] 4.4; 95% CI 3.5 to 5.5). Men had higher odds of riding unhelmeted (OR 1.6; 95% CI 1.4 to 1.9), as did weekend riders (OR 1.3; 95% CI 1.1 to 1.6). Use of bicycle helmets by users of public bikeshare programs is low. As these programs become more popular and prevalent, efforts to increase helmet use among users should increase.

EMG analysis of lower limb muscle activation pattern during pedaling: Experiments and computer simulations

The purpose of this study was to investigate the performance of the recumbent bicycle. The recumbent bicycle is a type of bicycle usually used to train or exercise a patient or the elderly. A recumbent bicycle was specially constructed for this study by researchers. The speed and power can be recorded and displayed on the monitor of the recumbent bicycle. The experiments consisted of four steps with different start-knee angle (α=85°, 105°, 125°, 145°). The activation and force of lower limb muscles were measured and calculated using an electromyography (EMG) and a computer simulation respectively. The maximum of intraclass correlation coefficients (ICC) and their differences were calculated to compare between the data of different muscles. The data obtained from test and retest was shown to have a good reliability on all of the measured muscles. The ICC is 0.93 for biceps femoris (BF) of step 2 (α=105°). The maximum muscle activation and muscle force were also measured at step 2. The BF EMG of step 2 was shown to be significantly different (p<0.05) from other steps. Overall, the recumbent bicycle was shown to be similar in function with an upright bicycle. The frequency use of the recumbent bicycle is predicted to increase for a patient and the elderly due to stable seat structure which have bucket shape.

Impact of Age, Location, and Bicycle Style on Helmet Usage by Adults

Objective: Our objective was to describe current patterns of bicycle helmet usage in a university community using a direct observation approach. Participants: Cyclists in a university community observed in 2010 and 2011. Methods: We identified 6 locations in Athens, Georgia, and recorded the type of bicycle, age group, sex, and helmet usage of passing cyclists. We performed univariate and multivariate analysis to identify independent predictors of helmet usage. Results: We observed 433 cyclists: 74 percent male, 74 percent college age, and 45 percent of whom wore a helmet. Helmet usage varied by bicycle type, location of observation, and age group. Independent predictors of bike helmet were on-campus location (0.38, 95% confidence interval [CI]: 0.22–0.66), college-age rider (0.29, 95% CI: 0.15–0.54), and use of a city or leisure bike (0.39, 95% CI: 0.23–0.65). Conclusions: College-age riders, riders on campus, and those riding a city or leisure-style bike are less likely to wear a helmet. Health promotion efforts aimed at increasing helmet usage should target these groups.

어린이용 자전거의 차량 충돌거동에 관한 연구

Abstract : Recently the usage of bicycle has increased steeply in Korea owing to traffic culture of well-being. In a car to bicycle accident investigation, the throw distance of bicycle is very important factor for reconstructing of the accident. The variables that influence on the throw distance of bicycle can be classified into the factors of vehicle and bicycle. Simulations and collision tests in actual car to bicycle accident were executed for obtaining throw distance of bicycle. The simulations were done by PC-CRASH TM and for actual crash tests sand bags were used for the behavior of bicyclist instead of dummy. Factors considered were vehicle velocity and the moving angles of bicycle, also the types of bicycle and vehicle were fairy cycle and automobile, respectively. From the results, the throw distances of a head-on tire collision of 0° direction was longer than that of tire crash test of 45° direction, and the throw distances of a head -on frame crash test of 90° direction was longer than that of frame crash test of 45° direction. In addition restitution coefficient between vehicle and bicycle was estimated as about 0.1 with based on actual crash tests. Finally the increaser vehicle velocity the longer the throw distances of bicycle, and the results of simulation were relatively good agreement to the experimental results.

Theoretical study of the mechanism for the gas‐phase pyrolysis kinetics of 2‐methylbenzyl chloride

AbstractThe study of the kinetics and mechanism of dehydrochlorination reaction of 2‐methyl benzyl chloride in the gas phase was carried out by means of electronic structure calculations using ab initio Móller‐Plesset MP2/6‐31G(d,p), and Density Functional Theory (DFT) methods: B3LYP/6‐31G(d,p), B3LYP/6‐31++G(d,p), MPW1PW91/6‐31G(d,p), MPW1PW91/6‐31++G(d,p)], PBE/6‐31G(d,p), PBE/6‐31++G(d,p). Investigated reaction pathways comprise: Mechanism I, a concerted reaction through a six‐centered cyclic transition state (TS) geometry; Mechanism II, a 1,3‐chlorine shift followed by beta‐elimination and Mechanism III, a single‐step elimination with simultaneous HCl and benzocyclobutene formation through a bicyclic type of TS. Calculated parameters ruled out Mechanism III and suggest the elimination reaction may occur by either unimolecular Mechanism I or Mechanism II. However, the TS of the former is 20 kJ/mole more stable than the TS of the latter. Consequently, the Mechanism I seem to be more probable to occur. The rate‐determining process is the breaking of C‐Cl bond. The involvement of π‐electrons of the aromatic system was demonstrated by NBO charges and bond order calculations. The reaction is moderately polar in nature. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 537–546, 2011

Research of the Joint Workspaces and Kinematic Efficiency of Man-Machine Systems of Bicycles

Bicycle design largely contradicts human motion, necessitating consideration of both the bicycle structure and the kinematic efficiency in the dimensions of the rider’s limbs, as well as human factor engineering, i.e. comfortability. By focusing on the kinematic model of 5-bar linkage and joints workspace, this study examines the most appropriate bicycle design and the riding posture to ensure that muscles can produce the effective moment and increase driving efficiency of a crank necessary. For upright, racing and recumbent bicycle types, assumptions are made regarding mobility analysis and the system of man-machine systems of bicycles estimated as well. Simulation results can identify the major dimensions of bicycle designing for different riders efficiently by inputting physical measurements of the rider and the angle range of driving force, subsequently increasing the riding efficiency to decrease the load of lower limbs of riders and satisfying ergonomic requirements of bicycle riders.

Interaction between Cyclist and Car during Broadside and Confrontation with Pedestrian Throw Formulas - Multibody Simulation

Although the issue of the injury of a cyclist in car collision is in lower when compared to that of pedestrians, we cannot ignore it completely. There is an increasing need to pay attention to bicycle safety due to the growing popularity of motorless single-track vehicles. This study investigates whether it is appropriate to analyze cyclist accidents using relations describing pedestrian throws and whether using simulation software Madymo models the side-impact collision caused by cars. This paper also describes how significant the form of the front parts of normal cars are, as well as the position of the cyclist on three types of bicycles. The analysis of formulas which estimate the car's speed before the impact contributes mainly to the field of judicial expertise and the investigation of car accidents.

Platinum(II)‐Catalyzed Reaction of γ,δ‐Ynones with Alkenes for the Construction of 8‐Oxabicyclo[3.2.1]octane Skeletons: Generation of Platinum‐Containing Carbonyl Ylides from Acyclic Precursors

Two types of bicycles can be prepared selectively by the title reaction, depending on whether or not a substituent is present at the propargylic position of the ynone substrate (see scheme). The cycloaddition of carbonyl ylides derived from γ,δ-ynones with vinyl ethers (or styrene) gave intermediate bicyclic carbene complexes, which underwent a 1,2-hydrogen-atom shift or rearrangement to provide the products. R1=alkyl, Ph; R3=alkyl.

Multi-value cellular automata model for mixed bicycle flow

In this paper, we investigate mixed bicycle flow using the multi-value cellular automata (CA) model. Two types of bicycles with different maximum speed are considered in the system. The system of mixed bicycles is investigated under both deterministic and stochastic regimes. It is shown under the deterministic case that there appear multiple states both in congested flow and free flow regions. Analytical analysis is carried out and is in good agreement with the simulation results. Under the stochastic case, the multiple states effect disappears only when both slow and fast bicycles are randomized. Spacetime plots are presented to show the evolution of mixed bicycle flow.

1111 自動車の統合制御による自律走行の研究 : ハンドル操舵角と重心移動量の場合

In this study, we deal with the autonomous run by the integrated control of a bicycle. Integrated control means the control by the steering angle, the movement of the rider and the driving forces. It is considered that the effect of the driving force control is big especially under low speed operation. Our final goal is to evaluate the stability and controllability of the various types of bicycles, with the feedback gains under autonomous run. In this report, as the first step, the experiments results of autonomous run only by the steering angle control are shown. The autonomous runs of about 9 seconds were achieved.

Effect of changing the saddle angle on the incidence of low back pain in recreational bicyclists.

OBJECTIVE: According to the literature, 30-70% of cyclists suffer from cervical, dorsal, or lumbar back pain. This study was conducted to evaluate one of the possible causes of low back...

Impact of laryngeal paralysis and its treatment on the glottic aperture and upper airway flow characteristics during exercise

Patients with unilateral vocal fold paralysis occasionally report shortness of breath during exercise. This symptom may persist in some patients after medialization thyroplasty. A review of the literature revealed no study that objectively evaluated laryngeal dynamics or airway flow characteristics during exercise after medialization thyroplasty for unilateral laryngeal paralysis. This study evaluates glottic aperture size and configuration as well as upper airway flow characteristics during exercise in 16 subjects. Six patients who underwent medialization thyroplasty for unilateral vocal fold paralysis were compared with 10 healthy control subjects. During a standardized exercise protocol on an incremental ergometer (bicycle type), real-time videolaryngoscopy was obtained and correlated in a synchronized fashion with maximum-effort respiratory efforts at the beginning, midpoint, and end of the exercise period. Direct calculations of glottic size during various phases of the exercise period were performed from digitized images. These data were correlated with inspiratory flow data for each patient. Patients with laryngeal paralysis demonstrated smaller mean glottic areas and lower peak inspiratory flow rates than controls both at rest and during all phases of the exercise period. This study suggests that after treatment of unilateral laryngeal paralysis with medialization thyroplasty, inspiratory flow rate and glottic area are significantly less than in normal controls. (Otolaryngol Head Neck Surg 1999;120:819-23.)