scholarly journals Practical Application of the Whipple and Carvallo Stability Model on Modern Bicycles with Pedal Assistance

2020 ◽  
Vol 10 (16) ◽  
pp. 5672
Author(s):  
Sien Dieltiens ◽  
Frederik Debrouwere ◽  
Marc Juwet ◽  
Eric Demeester
Keyword(s):  
Center Of Mass ◽  
Front Wheel ◽  
Stable Range ◽  
Stability Behaviour ◽  
Stability Model ◽  
Electric Bicycle ◽  
Electric Bicycles ◽  
The Stability ◽  
Extra Weight ◽  
Physically Challenged

Increasingly more people cycle with electrically-powered pedal assistance. The reduced pedalling effort attracts physically challenged people and seniors, who have a higher risk of falling. Since electric bicycles are heavier and the centre of masses are located higher, accidents happen easily. This study analyses the influence of the addition of a battery and motor unit on the stability behaviour of common bicycles for women. Based on market research, seven typical bicycle configurations are determined. Geometrics, mass values, and cycling postures are measured, and the theoretical stability behaviour is determined analytically based on the stability model of Whipple and Carvallo. The research shows that bicycles without pedal assistance have a smaller self-stable and semi-stable range than most electric bicycles. The electric bicycle with a motor implemented in the front wheel perform best, as the extra weight of the motor enhances the gyroscopic self-stabilization of the front wheel. Furthermore, a battery in the lower mid-tube is preferred over one in the luggage rack as it lowers the center of mass of the rear frame assembly. Knowledge about the optimal configuration to maximize the stability will enhance the cycling comfort and minimize the chance of accidents.

scholarly journals CONVERSION OF AN ORDINARY N BICYCLE INTO AN ELECTRIC BIKE AND RELATED RESEARCH / DVIRAČIO PERDARYMAS Į ELEKTRINĮ IR JO TYRIMAS

2014 ◽  
Vol 6 (2) ◽  
pp. 178-181
Author(s):  
Marius Janavičius
Keyword(s):  
Electric Vehicles ◽  
Front Wheel ◽  
Performance Characteristics ◽  
Related Research ◽  
Electric Bicycle ◽  
Electric Bicycles ◽  
Battery Technology ◽  
Lifepo4 Battery ◽  
Electric Bike

An electric bicycle as a transport and leisure vehicle is expected to have a promising future. Currently, he market offers a great choice of factory electric bicycles and conversion kits to remake an ordinary bicycle into an electric bike. Also, the increasing number of electric vehicles is determined by the reduction in costs for manufacturing of batteries and an evolution in battery technology. This article presents the implementation of an electric bike by selecting the “Golden Motor Technology” company’s electric front wheel conversion kit MagicPie3 and 16 cell 10Ah LiFePO4 battery. After installation of the engine and other components, experiments were conducted to evaluate the performance characteristics of the electric bike and check the manufacturer’s specifications. Elektriniams dviračiams, kaip transporto ir laisvalaikio praleidimo priemonėms, prognozuojamos geros perspektyvos. Šiuo metu rinkoje yra didelis pasirinkimas gamyklinių elektrinių dviračių ir adaptavimo komplektų paprastam dviračiui perdaryti į elektrinį. Elektrinių transporto priemonių gausėjimą lemia tobulėjančios ir pingančios maitinimo elementų technologijos bei gamyba. Straipsnyje aprašoma, kaip dviratį perdaryti į elektrinį pasirinkus „Golden Motor Technology“ kompanijos 26 colių skersmens priekinio elektrinio rato adaptavimo komplektą MagicPie3 ir 16 celių 10 Ah LiFePO4 bateriją. Sumontavus variklį ir kitus komponentus atlikti eksperimentai, siekiant įvertinti technines elektrinio dviračio charakteristikas ir patikrinti gamintojo nurodytas specifikacijas.

TO THE STABILITY OF TANK VEHICLES IN THE BRAKE MODE

2019 ◽  
pp. 27-32
Author(s):  
Denys Popelysh ◽  
Yurii Seluk ◽  
Sergyi Tomchuk
Keyword(s):  
Mathematical Model ◽  
Control Systems ◽  
Distribution Systems ◽  
Traffic Accidents ◽  
Road Traffic ◽  
Center Of Mass ◽  
Dynamic Processes ◽  
Course Stability ◽  
The Stability ◽  
Tank Vehicles

This article discusses the question of the possibility of improving the roll stability of partially filled tank vehicles while braking. We consider the dangers associated with partially filled tank vehicles. We give examples of the severe consequences of road traffic accidents that have occurred with tank vehicles carrying dangerous goods. We conducted an analysis of the dynamic processes of fluid flow in the tank and their influence on the basic parameters of the stability of vehicle. When transporting a partially filled tank due to the comparability of the mass of the empty tank with the mass of the fluid being transported, the dynamic qualities of the vehicle change so that they differ significantly from the dynamic characteristics of other vehicles. Due to large displacements of the center of mass of cargo in the tank there are additional loads that act vehicle and significantly reduce the course stability and the drivability. We consider the dynamics of liquid sloshing in moving containers, and give examples of building a mechanical model of an oscillating fluid in a tank and a mathematical model of a vehicle with a tank. We also considered the method of improving the vehicle’s stability, which is based on the prediction of the moment of action and the nature of the dynamic processes of liquid cargo and the implementation of preventive actions by executive mechanisms. Modern automated control systems (anti-lock brake system, anti-slip control systems, stabilization systems, braking forces distribution systems, floor level systems, etc.) use a certain list of elements for collecting necessary parameters and actuators for their work. This gives the ability to influence the course stability properties without interfering with the design of the vehicle only by making changes to the software of these systems. Keywords: tank vehicle, roll stability, mathematical model, vehicle control systems.

A novel path tracking approach considering safety of the intended functionality for autonomous vehicles

2021 ◽  
pp. 095440702110205
Author(s):  
Huiran Wang ◽  
Qidong Wang ◽  
Wuwei Chen ◽  
Linfeng Zhao ◽  
Dongkui Tan
Keyword(s):  
Autonomous Vehicles ◽  
Autonomous Vehicle ◽  
Coordinated Control ◽  
Steering System ◽  
Front Wheel ◽  
Path Tracking ◽  
Hierarchical Architecture ◽  
Automatic Steering ◽  
The Stability ◽  
Control Layer

To reduce the adverse effect of the functional insufficiency of the steering system on the accuracy of path tracking, a path tracking approach considering safety of the intended functionality is proposed by coordinating automatic steering and differential braking in this paper. The proposed method adopts a hierarchical architecture consisting of a coordinated control layer and an execution control layer. In coordinated control layer, an extension controller considering functional insufficiency of the steering system, tire force characteristics and vehicle driving stability is proposed to determine the weight coefficients of automatic steering and the differential braking, and a model predictive controller is designed to calculate the desired front wheel angle and additional yaw moment. In execution control layer, a H∞ steering angle controller considering external disturbances and parameter uncertainty is designed to track desired front wheel angle, and a braking force distribution module is used to determine the wheel cylinder pressure of the controlled wheels. Both simulation and experiment results show that the proposed method can overcome the functional insufficiency of the steering system and improve the accuracy of path tracking while maintaining the stability of the autonomous vehicle.

Stability of Milling Operations With Asymmetric Cutter Dynamics in Rotating Coordinates

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Alptunc Comak ◽  
Orkun Ozsahin ◽  
Yusuf Altintas
Keyword(s):  
Time Domain ◽  
Machine Tools ◽  
High Speed ◽  
End Mill ◽  
Spindle Shaft ◽  
Milling Operations ◽  
Stability Model ◽  
Principal Directions ◽  
The Stability ◽  
Rotating Coordinates

High-speed machine tools have parts with both stationary and rotating dynamics. While spindle housing, column, and table have stationary dynamics, rotating parts may have both symmetric (i.e., spindle shaft and tool holder) and asymmetric dynamics (i.e., two-fluted end mill) due to uneven geometry in two principal directions. This paper presents a stability model of dynamic milling operations with combined stationary and rotating dynamics. The stationary modes are superposed to two orthogonal directions in rotating frame by considering the time- and speed-dependent, periodic dynamic milling system. The stability of the system is solved in both frequency and semidiscrete time domain. It is shown that the stability pockets differ significantly when the rotating dynamics of the asymmetric tools are considered. The proposed stability model has been experimentally validated in high-speed milling of an aluminum alloy with a two-fluted, asymmetric helical end mill.

Effects of finite-rate chemistry and detailed transport on the instability of jet diffusion flames

2014 ◽  
Vol 745 ◽  
pp. 647-681 ◽  
Author(s):  
Yee Chee See ◽  
Matthias Ihme
Keyword(s):  
Transport Properties ◽  
Diffusion Flames ◽  
Diffusive Transport ◽  
Mean Flow ◽  
Stability Behaviour ◽  
Jet Diffusion Flames ◽  
One Step ◽  
The Mean ◽  
Modelling Assumptions ◽  
The Stability

AbstractLocal linear stability analysis has been shown to provide valuable information about the response of jet diffusion flames to flow-field perturbations. However, this analysis commonly relies on several modelling assumptions about the mean flow prescription, the thermo-viscous-diffusive transport properties, and the complexity and representation of the chemical reaction mechanisms. In this work, the effects of these modelling assumptions on the stability behaviour of a jet diffusion flame are systematically investigated. A flamelet formulation is combined with linear stability theory to fully account for the effects of complex transport properties and the detailed reaction chemistry on the perturbation dynamics. The model is applied to a methane–air jet diffusion flame that was experimentally investigated by Füriet al.(Proc. Combust. Inst., vol. 29, 2002, pp. 1653–1661). Detailed simulations are performed to obtain mean flow quantities, about which the stability analysis is performed. Simulation results show that the growth rate of the inviscid instability mode is insensitive to the representation of the transport properties at low frequencies, and exhibits a stronger dependence on the mean flow representation. The effects of the complexity of the reaction chemistry on the stability behaviour are investigated in the context of an adiabatic jet flame configuration. Comparisons with a detailed chemical-kinetics model show that the use of a one-step chemistry representation in combination with a simplified viscous-diffusive transport model can affect the mean flow representation and heat release location, thereby modifying the instability behaviour. This is attributed to the shift in the flame structure predicted by the one-step chemistry model, and is further exacerbated by the representation of the transport properties. A pinch-point analysis is performed to investigate the stability behaviour; it is shown that the shear-layer instability is convectively unstable, while the outer buoyancy-driven instability mode transitions from absolutely to convectively unstable in the nozzle near field, and this transition point is dependent on the Froude number.

Evaluation of Non-Vibrating Utility Burner/Furnace Systems for Resistance to Thermoacoustic Oscillations

2006 ◽  
Author(s):  
Frantisek L. Eisinger ◽  
Robert E. Sullivan
Keyword(s):  
Design Process ◽  
Axial Direction ◽  
Stability Diagram ◽  
Stable Range ◽  
Design Engineers ◽  
Secondary Role ◽  
The Stability ◽  
Thermoacoustic Oscillations

Six burner/furnace systems which operated successfully without vibration are evaluated for resistance to thermoacoustic oscillations. The evaluation is based on the Rijke and Sondhauss models representing the combined burner/furnace (cold/hot) thermoacoustic systems. Frequency differences between the lowest vulnerable furnace acoustic frequencies in the burner axial direction and those of the systems’ Rijke and Sondhauss frequencies are evaluated to check for resonances. Most importantly, the stability of the Rijke and Sondhauss models is checked against the published design stability diagram of Eisinger [1] and Eisinger and Sullivan [2]. It is shown that the resistance to thermoacoustic oscillations is adequately defined by the published design stability diagram to which the evaluated cases generally adhere. Once the system falls into the stable range, the frequency differences or resonances appear to play only a secondary role. It is concluded, however, that in conjunction with stability, the primary criterion, sufficient frequency separations shall also be maintained in the design process to preclude resonances. The paper provides sufficient details to aid the design engineers.

scholarly journals Turning Gait Planning Method for Humanoid Robots

2018 ◽  
Vol 8 (8) ◽  
pp. 1257 ◽  
Author(s):  
Tianqi Yang ◽  
Weimin Zhang ◽  
Xuechao Chen ◽  
Zhangguo Yu ◽  
Libo Meng ◽  
...  
Keyword(s):  
Inverted Pendulum ◽  
Center Of Mass ◽  
Translational Motion ◽  
Humanoid Robots ◽  
Inverted Pendulum Model ◽  
Straight Line ◽  
Pendulum Model ◽  
The Stability ◽  
And Control ◽  
Present Simulation

The most important feature of this paper is to transform the complex motion of robot turning into a simple translational motion, thus simplifying the dynamic model. Compared with the method that generates a center of mass (COM) trajectory directly by the inverted pendulum model, this method is more precise. The non-inertial reference is introduced in the turning walk. This method can translate the turning walk into a straight-line walk when the inertial forces act on the robot. The dynamics of the robot model, called linear inverted pendulum (LIP), are changed and improved dynamics are derived to make them apply to the turning walk model. Then, we expend the new LIP model and control the zero moment point (ZMP) to guarantee the stability of the unstable parts of this model in order to generate a stable COM trajectory. We present simulation results for the improved LIP dynamics and verify the stability of the robot turning.

Simple Leg Placement Strategy for a One Legged Running Model

2012 ◽  
Author(s):  
Timothy Sullivan ◽  
Justin Seipel
Keyword(s):  
Stance Phase ◽  
Energy State ◽  
Center Of Mass ◽  
Mass Movement ◽  
Legged Locomotion ◽  
Energy Conserving ◽  
Lower Torque ◽  
The Stability ◽  
Time Required ◽  
Torque Values

The Spring Loaded Inverted Pendulum (SLIP) model was developed to describe center of mass movement patterns observed in animals, using only a springy leg and a point mass. However, SLIP is energy conserving and does not accurately represent any biological or robotic system. Still, this model is often used as a foundation for the investigation of improved legged locomotion models. One such model called Torque Damped SLIP (TD-SLIP) utilizes two additional parameters, a time dependent torque and dampening to drastically increase the stability. Forced Damped SLIP (FD-SLIP), a predecessor of TD-SLIP, has shown that this model can be further simplified by using a constant torque, instead of a time varying torque, while still maintaining stability. Using FD-SLIP as a base, this paper explores a leg placement strategy using a simple PI controller. The controller takes advantage of the fact that the energy state of FD-SLIP is symmetric entering and leaving the stance phase during steady state conditions. During the flight phase, the touch down leg angle is adjusted so that the energy dissipation due to dampening, during the stance phase, compensates for any imbalance of energy. This controller approximately doubles the region of stability when subjected to velocity perturbations at touchdown, enables the model to operate at considerably lower torque values, and drastically reduces the time required to recover from a perturbation, while using less energy. Finally, the leg placement strategy used effectively imitates the natural human response to velocity perturbations while running.

Design and Analysis of Electric Bikes for Local Commutes

2015 ◽  
Author(s):  
Preston Moore ◽  
Chase Vande Velde ◽  
Richard Wagner ◽  
Christopher Depcik
Keyword(s):  
Public Transportation ◽  
Center Of Mass ◽  
Physical Exertion ◽  
Front Wheel ◽  
Motor Vehicles ◽  
First Year ◽  
Average Height ◽  
Potential Solution ◽  
Direct Drive ◽  
Environmental Benefit

In today’s society, those who do not take advantage of public transportation services typically drive personal vehicles to school, work, and other locations of interest. Due to the required amount of physical exertion, walking or riding a bike is often avoided. This is concerning given that a large percentage of carbon and hazardous emissions emanate from motor vehicles. This creates a need for an alternative means of travel for shorter commutes with electric bikes (e-bikes) one potential solution. They have zero tailpipe emissions and significantly lower overall emissions relative to motorized vehicles; however, their cost often prevents them from being readily marketable. In order to address this issue, two undergraduate capstone design teams have constructed e-bikes using recycled and donated parts over the past two years. In the first year, the runner from a pickup truck was scavenged from a junkyard and employed as the frame to provide for the greatest environmental benefit. However, this resulted in an odd bicycle shape because of limited material availability. As a result, the second years team decided to use a donated chrome moly tube as the frame while focusing on ergonomics and aesthetics. This second bike was designed so that a male rider of average height (5′10″ – 1.78 m) could complete commutes of several miles in relative comfort. Both e-bikes employ a direct drive motor (first year – front wheel; second year – back wheel) to provide assistance when needed, leaving the rider less fatigued. To promote further development in electric bike design, each team has made a considerable effort to record the design process with highlights presented in this effort. Furthermore, e-bike testing results are presented including center of mass calculations, braking distances, turning radii, and overall efficiencies quantified by the miles traveled using the same battery pack. This information will be used to compare the bikes against each other in order to illustrate bike attributes that are desired when an electric motor is employed. The result is an appealing, cost-effective, and efficient electrical bike that will greatly reduce traffic related emissions should it become widely implemented. Given the issues related to transportation at a university (e.g., available parking) including the reticence of students to traverse long distances across campus to attend classes, it is believed that this effort can serve as a model example to other universities who might see e-bikes as a potential solution to reducing congestion and improving student attendance.

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