Human-powered Vehicles Research Articles

Human-powered vehicles as a way to abate transport-related greenhouse gas emissions: Part 2 - A virtual prototype for emissions and performance analyses

Velomobiles, despite their potential for efficient transportation, remain relatively unknown compared to electric cars, receiving limited attention in academic research and public awareness. This paper highlights their untapped potential and underlines public interest in their adoption, provided a velomobile meeting customer requirements is available. Leveraging the Model Based System Engineering (MBSE) methodology, this work presents a structured approach to design, focusing on customer needs translation and digital prototype validation. This iterative process ensures velomobiles meet performance criteria while minimizing environmental impact. The lack of standardized testing for the energy consumption of Human-Powered Vehicles (HPVs) is addressed by proposing an analysis of consumption under diverse operating conditions, giving information on the environmental assessments. This study underscores velomobiles’ potential as a sustainable transportation solution and provides a framework for their design, validation, and optimization.

Comparison of different supervised learning algorithms for position analysis of the slider-crank mechanism

Slider-crank mechanisms have a wide range of applications in machine design, primarily for converting rotary motion into reciprocating motion, as seen in internal combustion engines, pumps, compressors, and human-powered vehicles. Due to their widespread usage, analytical and graphical solutions for the position analysis of slider-crank mechanisms are introduced in various textbooks and lecture notes. Recently, artificial neural network algorithms have been applied to various design applications across different research fields, and mechanism design is no exception. However, investigations into the application of neural network algorithms specifically to slider-crank mechanisms are quite limited. In this study, the analytical position analysis of the slider-crank mechanism is presented, and datasets are obtained first. Subsequently, the application of following three different supervised learning algorithms to the position analysis of the slider-crank (R-RRT) mechanism is investigated using analytical solution datasets: the Levenberg-Marquardt Backpropagation (LM) algorithm, Bayesian Regularization (BR) algorithm, and Scaled Conjugate Gradient Descent (SCG) algorithm. These three algorithms were chosen due to their distinct characteristics. The main objectives of this study are to highlight the differences among various neural network algorithms' applications and to understand the applicability and suitability of different neural network algorithms for kinematic position analysis in mechanisms. The results indicate that the Bayesian regularization algorithm yields the best results, while the Levenberg-Marquardt Backpropagation algorithm exhibits the best performance.

Survey-Based Accident Analysis for Human-Powered Three-Wheeled Vehicles

The causes of accidents involving nonconventional bicycle types have hardly been investigated in the literature to date. However, these vehicles could play an important role in reducing the CO2 emissions generated by traffic. As a basis for improving the driving safety of these environmentally friendly vehicles, this article presents the results of a survey on accidents and near-accidents of multitrack bicycle vehicles. More than 120 critical or accident situations of 86 drivers were analyzed. The situations are investigated with respect to the circumstances, the causes, and the consequences of the accidents using manual analysis and multiple correspondence analysis. A distinction is made between single accidents and accidents with another party. The aim of the survey is not to make statistically accurate statements on the frequency and probability of accidents, but rather to analyze the accident or near-accident circumstances. It is shown that the causes of single accidents are usually too high cornering velocities in combination with other factors such as road conditions. In the case of accidents with external involvement, the person who caused the accident is usually the other party involved. The accident opponent is in most cases a passenger car. Here the overlooking of the vehicles is the most frequent cause of accidents. Finally, possibilities to reduce the probability of accidents are briefly discussed for the different situations. As the research shows, most of the situations described occur on the road. This indicates that there are deficits in the bicycle infrastructure for the vehicles considered here. The results also indicate that there are deficits with regard to the perceptibility of the vehicles by other road users.

Mass Data Measurement, Approximation and Influence on Vehicle Stability for Ultra-Light Human-Powered Vehicles

The mass properties of a vehicle play a decisive role in its dynamics and characteristics and are fundamental for vehicle dynamics models and controllers. These values are not yet known for the vehicle class of the ultra-light velomobiles and similar multi-track bicycle vehicles. In the future, however, such vehicles could play a role in reducing the CO2 emissions generated by individual transportation. As a basis for vehicle dynamics modeling, accident reconstruction, and controller development for this vehicle class, this paper investigated ranges of mass properties and their influence on vehicle stability considering driver influence. In total, 13 vehicles (10 velomobiles and 3 trikes) were examined using different experimental setups. It was shown that most vehicles exhibited understeering behavior based on the center of gravity position and calculations of the static stability factor showed significantly lower rollover stability compared with conventional vehicles. The measured moments of inertia were used to develop and examine different approximation approaches for the yaw moment of inertia using conventional approaches from the passenger car sector and stepwise regression. This created the basis for parameter estimation from easily measurable vehicle parameters and provided the possibility to generate realistic parameter sets for vehicle dynamic models. Existing tests do not consider the influence of driver movements, such as pedaling movements or possible inclination of the upper body. This offers the potential for further investigations of the dynamic influences on the investigated variables.

Handbike: Systematic review and prospective study

People with motor disabilities present diverse needs that the available products cannot fully addresses. Handbikes are human-powered vehicles that provide mechanical efficiency and can be used as a product for every day. The objective of this study is to understand how the design aspects of these vehicles have been investigated. As a methodology adopted, a systematic literature review was carried out, in order to find relevant scientific articles on the subject, and a prospective study, to verify the prospective scenario. For the selection criteria adopted, 21 scientific studies and 17 patents, none in Brazil, were found on the research platforms. These results demonstrate that there is potential to work with handbikes in the country due to the market gap.

Experimental Comparison of Speed-Dependent Rolling Coefficients in Small Cycling Tires

ABSTRACTIn this article, the methodology and results of an experimental campaign on small and slick bicycle tires are presented. The test was developed to compare the rolling resistance of tires to be used in high-speed competitions for streamlined human-powered vehicles. After an explanation of the theoretical background for the measurement, the test-rig and the adopted procedure to measure and subtract aerodynamic effects are presented. The obtained data show that the rolling resistance coefficient has a nonlinear dependency from the speed between 45 and 145 km/h. The data comparison points out a decrease in rolling losses up to 54% by switching from a butyl to latex inner tube on the same tire, whereas no significant difference is detected between the latex tube and tubeless configuration. An estimation of the impact on racing performance is provided, showing that selecting the best option could save up to 19% of the overall effort energetic cost, which means a higher final speed can be achieved with the same rider effort. Finally, a speculative analysis is proposed that considers different functions to fit the obtained data, pointing out the need for experimental measurements on the very-low-speed region to achieve a better understanding of the entire rolling resistance behavior with respect to speed.

From PBL to innovation: a decennial case-study from an HPV student team

Purpose The implementation of project-based learning (PBL) activities in the curricula of engineering students has become a consolidated method to improve their skills. The purpose of this paper is to share the experience acquired by the authors from a decennial case-study on a student team PBL activity focused on design and development of human-powered vehicles (HPVs). A review of the project evolution, boundary constraints and management choices could provide inspiration and suggestions to faculty staff that would like to set-up similar experiences for engineering students in their universities. Design/methodology/approach A student team was funded by the authors in 2008 to gather engineering students interested in design and construction of HPVs. In the past decade, the team has grown from 10 up to 60 students enrolled per year and stimulated to develop a range of HPV designs for sports and mobility. The project management evolved as a consequence to com ply with the growing ambitions of the group and complexity of the goals. Findings A thorough analysis of factors contributing to the success of the project led to identification of the key factors to increase student participation: persistence of the faculty staff is essential, attending competitions and challenges increases students’ recruitment and formal recognition of the activity through credits and the implementation of intermediate assessment steps increase the active participation rate. Bigger teams reduce the negative impact of recruits eventually abandoning the project in an early stage. Ambitious goals keep students motivated for longer periods and enable a virtuous circle by transferring enthusiasm and knowledge to new members. Research limitations/implications The activity is analyzed starting from a subjective experience perspective and some of the findings/conclusions may be not applicable in a different context. However, such review can suggest strategies on the long-term period to create similar conditions elsewhere. Social implications In the last part of the paper, it is pointed out how PBL projects can provide a fertile ground for innovation and lead to patents and development of new products aiming at the market. Originality/value This study contributes to provide an insight view of how a student team PBL activity can grow over a decade if guided by faculty staff.

Cargo-bicycle with a Polymeric Frame: The Development of a Low-cost Multifunctional Cargo Bicycle

Since the beginning of the 21st century, human-powered vehicles are increasingly seen as an attractive alternative to solve some of the problems associated with mobility in major cities. Firmly rooted in Northern Europe’s Social and cultural behaviour, cargo bicycles are beginning to spread all over the globe and, in this sense, it is expectable a global outbreak on this market.A cargo bike that considers the use of a polymer as a raw material to build its frame opens a new window of opportunities for new and disruptive designs. A frame like this raises some new shape and structural challenges. But by taking advantage of existing technologies and combining them, made it possible to achieve results that exceeded by far the initial expectations.It is not intended to reinvent the bicycle, neither to propose it for new uses, others already addressed these issues. Instead, the goal is to redesign this machine, exploring new frame designs, to adopt Polypropylene as a structural material and explore injection moulding as a manufacturing processes.

The PurdueTracer: An Energy-Efficient Human-Powered Hydraulic Bicycle with Flexible Operation and Software Aids

Hydrostatic transmissions (HT) are widely applied to heavy-duty mobile applications because of the advantages of layout flexibility, power to weight ratio, and ease of control. Though applications of fluid power in light-duty vehicles face challenges, including the unavailability of off-the-shelf components suitable to the power scale, there are potential advantages for HTs in human-powered vehicles, such as bicycles, the most important one being the energy-saving advantage achievable through regenerative braking in a hybrid HT. This paper describes an innovative design for a hydraulic hybrid bicycle, i.e., the PurdueTracer. The PurdueTracer is an energy-efficient human-powered hydraulic bicycle with flexible operation and software aids. An open-circuit hydraulic hybrid transmission allows PurdueTracer to operate in four modes: Pedaling, Charging, Boost, and Regeneration, to satisfy users’ need for different riding occasions. An aluminum chassis that also functions as a system reservoir was customized for the PurdueTracer to optimize the durability, riding comfort, and space for components. The selection of the hydraulic components was performed by creating a model of the bicycle in AMESim simulation software and conducting a numerical optimization based on the model. The electronic system equipped users with informative feedback showing the bicycle performance, intuitive execution of functions, and comprehensive guidance for operation. This paper describes the design approach and the main results of the PurdueTracer, which also won the 2017 National Fluid Power Association Fluid Power Vehicle Challenge. This championship serves to prove the excellence of this vehicle in terms of effectiveness, efficiency, durability, and novelty.

APPLICATION OF FUNCTIONAL ELEMENTS TO THE CONCEPTUAL DESIGN OF INNOVATIVE HUMAN-POWERED VEHICLES

The purpose of this paper is to propose a simple and quick process for creating new design concepts for human-powered vehicles. First, the design theme for an innovative bicycle is described. Next, the functional elements of the bicycle are selected according to the contents described in the design theme. Based on the design requirements, various spatial arrangements of the creative functional elements are produced. In the final step, we followed the flowchart of the creative functional elements constructed by this research and demonstrated a case study design.

CFD analysis of internal ventilation in high-speed human powered vehicles

When dealing with fully faired human powered vehicles (HPVs) for speed or endurance record attempts, the need for internal ventilation of the rider arises. Different solutions have been proposed in the literature and in practice by designers and builders of these bicycles. The present paper proposes an analytical approach to design the frontal air inlet according to the VO $$_{2}$$ max of the rider in speed competitions. A 3D computational fluid dynamics (CFD) model is presented to analyse the external and internal flow interaction with respect to three design parameters: the presence of wheel covers, the location of the rear vent and its geometry. The CFD results predict that the wheel covers save 23 W of aerodynamic power at 125 km/h. A secondary but significant design parameter is the rear vent position that can provide a further reduction of 11 W at 125 km/h if properly located. Finally, the effect of the rear vent geometry was below the model confidence level, resulting in a likely negligible design parameter.

Ergonomic study on human-powered vehicles

In this paper, new methods for ergonomic analysis of cyclist for 4-wheel recumbent seat human-powered vehicle (HPV) are performed. An ergonomic index with fundamental formulation is developed in order to determine the level of comfortness during handling of the HPV. Basic reference of sitting postures are produced from three HPVs for 20 different individuals. All the dimensions, angles and measurements are recorded. The same individuals are required to sit on the three HPV models to evaluate their comfortness and ergonomic by observing the same dimensions, angles and measurements of leg and hand postures. The data is compared with reference comfort sitting ergonomic. This study is limited to a number of individuals which are the students of a university in Malaysia with age range from 20 to 24 years old. However, the ergonomic index can be expanded for Asian people and with some improvement in the parameters, it can be used for other countries. Derivation of ergonomic index and formulation in determining the comfort level and ergonomic of HPV. Using the ergonomic index, a new improved HPV can be developed. The index is also applicable with modification on several parameters in the formulation for other countries.

Rolling resistance, vertical load and optimal number of wheels in human-powered vehicle design

Even if it makes a smaller contribution than aerodynamic drag, rolling resistance plays a non-negligible role in the efficiency of human-powered vehicles, whether they are designed for daily commuting or to set speed records. The literature, experimental evidence and models show that the rolling resistance coefficient of cycling wheels strongly depends on the supported load, suggesting that the number of wheels and the load distribution could play a role in vehicle design and in road-test data analysis. Starting with an in-depth look at the relationship between a single wheel and overall vehicle rolling resistance coefficients, an analysis is proposed and discussed with the aim of minimizing the rolling resistance of a vehicle. Finally, a parametric surface response model for rolling resistance is obtained as a function of wheel size and the number of wheels. The overall analysis overturns the popular assumption according to which ‘the more wheels, the more rolling resistance’, at least according to a strict definition of the phenomenon.

Recumbent vs. upright bicycles: 3D trajectory of body centre of mass, limb mechanical work, and operative range of propulsive muscles

ABSTRACTRecumbent bicycles (RB) are high performance, human-powered vehicles. In comparison to normal/upright bicycles (NB) the RB may allow individuals to reach higher speeds due to aerodynamic advantages. The purpose of this investigation was to compare the non-aerodynamic factors that may potentially influence the performance of the two bicycles. 3D body centre of mass (BCoM) trajectory, its symmetries, and the components of the total mechanical work necessary to sustain cycling were assessed through 3D kinematics and computer simulations. Data collected at 50, 70, 90 110 rpm during stationary cycling were used to drive musculoskeletal modelling simulation and estimate muscle-tendon length. Results demonstrated that BCoM trajectory, confined in a 15-mm side cube, changed its orientation, maintaining a similar pattern across all cadences in both bicycles. RB displayed a reduced additional mechanical external power (16.1 ± 9.7 W on RB vs. 20.3 ± 8.8 W on NB), a greater symmetry on the progression axis, and no differences in the internal mechanical power compared to NB. Simulated muscle activity revealed small significant differences for only selected muscles. On the RB, quadriceps and gluteus demonstrated greater shortening, while biceps femoris, iliacus, and psoas exhibited greater stretch; however, aerodynamics still remains the principal benefit.

First motorcycle-exclusive lane (Motovia) in Colombia: perceptions of users in Cali, 2012–2013

This study's goal was to evaluate the pilot exclusive lane for motorcycles (Motovía) in Cali, Colombia, from the perception of its users in 2012–2013. A cross-sectional study using roadside surveys plus a qualitative component of individual semi-structured interviews was carried out. Road users' perceptions were investigated before and after implementation of lane dividers (LD) and were compared with other roads in the city. Perceptions were compared using chi-square tests. In the study, 293 motorcyclists, 111 cyclists, and 115 automobile drivers were interviewed. Following the installation of the LD, the majority of motorcyclists and cyclists reported that LD made easier the driving maneuvers and decreased travel time, in contrast to perceptions of automobile drivers (p < 0.001). For most motorcyclists, the Motovia was considered as safe and effective, approving its continuity and replication. Half of automobile drivers and cyclists did not approve the installation of the Motovia due to travel time (drivers) and security issues (cyclists). Motovia is an option to enhance motorcyclists' safety on the road. It must, however, offer clear circulation alternatives for automobile drivers. According to users' perception, it is not safe for bicycles and other human-powered vehicles to share lanes with motorcycles. Further research about vulnerable road users' infrastructure is required.

Design of a hybrid propulsion system for a three wheeled bicycle

Purpose – Velomobiles or bicycles cars are human-powered vehicles, enclosed for improving aerodynamic performance and protection from weather and collisions. The purpose of this paper is to design and develop a three-wheeled velomobile equipped with a hybrid human-electric propulsion system. Design/methodology/approach – The mechanical layout has been developed in order to improve safety, a CAD code has been used for the design and the dynamic performances have been studied by means of specific multi-body codes. The electric propulsion system has been designed both with analytical and FEM methods. Findings – A special three-wheeled tilting vehicle layout equipped with a four-bar linkage connection has been developed. A particular synchronous reluctance machine has been developed, which is very suitable for human-electric hybrid propulsion. A MATLAB code for integrated mechanical and electrical analysis has been developed. Originality/value – A new kind of light vehicle has been conceived. A new synchronous reluctance machine with high efficiency has been developed. A performance analysis in electric, human and hybrid working modes has been presented, which takes into account the specific features of both the electric motor and the pedaling legs. A prototype of the vehicle has been built.

Impacting the Community through a Sophomore Design Experience

Cornerstone design at James Madison University is a two-semester, client-based service learning project. Each year, sophomore engineering students work to design human-powered vehicles for a community member with needs very different from their own as a result of cerebral palsy. This paper provides a reflection of the fifth iteration (2013-2014) of this year-long sophomore design experience with the overarching goal to provide a transferable model such that other engineering programs may learn from our lessons and develop their own service learning experience. The reflection contained in this paper was catalyzed through participation in the National Science Foundation-funded Integrating Design and Community Engagement within the Curriculum Workshop hosted at Purdue University from June 19-20, 2014. In addition to reflection on the course, the paper provides insight into course coordination and assessment, and lessons learned over the past five years.

A METHOD FOR IMPROVING BICYCLE SHIFTING PERFORMANCE

The overwhelming majority of bicycles, the most common human–powered vehicles (HPVs), are equipped with sophisticated derailleur systems that serve the same purpose as transmissions in motor vehicles: enabling more efficient use of input power through selection of suitable gear reduction ratios. This paper presents a method for improving the performance of bicycle derailleur systems by modifying sprocket shape to eliminate jerkiness, slippage and rattling noise, and guide chain movement from one gear to another more quickly and directly. The sprocket modification CAD/CAM program, and an integrated optimization tool, were developed on an IRIS INDIG0/4000 workstation.

On-road and Wind Tunnel Aerodynamic Study of Human Powered Vehicles

The aim of the Royal Automotive Club of Victoria (RACV) Energy Breakthrough annual event is to provide an opportunity to school students to design and develop human powered vehicles (HPVs) and race a nonstop 24hours event that requires energy conservation, endurance and reliability. The event involves primary and secondary school students, teachers, parents and local industry to work together on the design and use of energy efficient vehicles. The key areas with interest of HPVs are the significance of aerodynamic design and ways to improve overall aerodynamics as most HPVs are designed with minimal or no aerodynamic consideration. Therefore, the primary objective of this study is to examine the aerodynamic behaviour of two production HPVs of variable designs using on-road, wind tunnel experimentations and Computational Fluid Dynamics (CFD) modelling. The study shows that the aerodynamic efficiency of vehicle largely depends on external shape especially the extrusion, gaps and bumps. The useful data can be obtained and utilized using wind tunnel and on-road tests for HPVs if a close replica along is used.

Aerodynamic study of Human Powered Vehicles

The key areas with interest of Human Powered Vehicles (HPVs) are the significance of aerodynamic design and ways to improve overall aerodynamics. Wind tunnel testing was undertaken at the RMIT wind tunnel with a selection of both faired and unfaired vehicles. Within these tests and vehicles different components were also analysed and tested. The wind tunnel testing was used to identify key characteristics of these HPVs, and, by identifying the different results obtained it was possible to understand more about the aerodynamics of HPV. Drag force values were obtained during wind tunnel testing, these drag values were compiled and compared. A key result was the importance of fairings, where travel could require significantly less effort as the faired vehicle tested provided only a quarter of the aerodynamic hindrance of any of the unfaired vehicles. Another significant finding was the effect of vehicle add-ons which showed how some apparently small components could have a relatively large negative impact on drag.