Braking Effect Research Articles

Impact of magnetic braking on high-mass close binary formation

ABSTRACT Combining numerical simulations and analytical modelling, we investigate whether close binary systems form by the effect of magnetic braking. Using magnetohydrodynamics simulations, we calculate the cloud evolution with a sink, for which we do not resolve the binary system or binary orbital motion to realize long-term time integration. Then, we analytically estimate the binary separation using the accreted mass and angular momentum obtained from the simulation. In unmagnetized clouds, wide binary systems with separations of >100 au form, in which the binary separation continues to increase during the main accretion phase. In contrast, close binary systems with separations of <100 au can form in magnetized clouds. Since the efficiency of magnetic braking strongly depends on both the strength and configuration of the magnetic field, they also affect the formation conditions of a close binary. In addition, the protostellar outflow has a negative impact on close binary formation, especially when the rotation axis of the prestellar cloud is aligned with the global magnetic field. The outflow interrupts the accretion of gas with small angular momentum, which is expelled from the cloud, while gas with large angular momentum preferentially falls from the side of the outflow on to the binary system and widens the binary separation. This study shows that a cloud with a magnetic field that is not parallel to the rotation axis is a favourable environment for the formation of close binary systems.

Conceptual design evaluation of concurrent brake actuator mechanism

The proper amount of braking force on both wheels is needed to optimize the braking performance and stability of the motorcycle. The braking effectiveness can be maximized by keeping the ideal nonlinear brake force distribution during braking. Thus the purpose of this research is to present a mechanism that can be accommodated as a Concurrent Brake Actuator (CBA) design to control the ideal nonlinear brake force distribution. In this paper, the conceptual design of the CBA mechanism is developed to be used as a based design for CBA development. Thus, two conceptual designs of the CBA mechanism have been generated. The proposed concept designs were evaluated based on Design Failure Mode and Effect Analysis (DFMEA) and SOLIDWORKS Motion Analysis. The potential failure of the CBA concept design was determined based on the risk priority number (RPN) in DFMEA. The information obtained from DFMEA was used in SOLIDWORKS Motion Analysis to identify stress performance analysis for each CBA conceptual design. Then, the best CBA concept design will be selected. The selection was made based on the highest score gained by the CBA concept design in qualitative evaluation. Based on the results, the fixed main body design with a tilted position linear slope in CBA Design I is potentially to actuate and distribute the nonlinear brake force to the front and rear brake with less potential of failure. Therefore, the proposed mechanism design will be used as a based mechanism design for CBA development.

Research on regenerative braking system for linear control chassis platform

The regenerative braking system of the electric vehicle with the linear control chassis plays an important role in improving the mileage of the vehicle, which mainly solves the problem of large electricity demand for the linear control chassis. After analyzing the structural characteristics of the linear control chassis, the constraints of regenerative braking and the existing regenerative braking control strategies, a new regenerative braking control strategy is proposed, and the control strategy is modified. The regenerative braking control strategy model is established by Simulink / Stateflow, and the braking effect and energy recovery efficiency are verified by changing the initial braking speed. The simulation results show that the strategy can well complete the braking task of the vehicle, and the braking energy recovery rate increases with the increase of the initial braking speed. Reasonable control strategy can effectively improve vehicle energy recovery efficiency.

Gait Speed Modulations Are Proportional to Grades of Virtual Visual Slopes-A Virtual Reality Study.

Gait is a complex mechanism relying on integration of several sensory inputs such as vestibular, proprioceptive, and visual cues to maintain stability while walking. Often humans adapt their gait to changes in surface inclinations, and this is typically achieved by modulating walking speed according to the inclination in order to counteract the gravitational forces, either uphill (exertion effect) or downhill (braking effect). The contribution of vision to these speed modulations is not fully understood. Here we assessed gait speed effects by parametrically manipulating the discrepancy between virtual visual inclination and the actual surface inclination (aka visual incongruence). Fifteen healthy participants walked in a large-scale virtual reality (VR) system on a self-paced treadmill synchronized with projected visual scenes. During walking they were randomly exposed to varying degrees of physical-visual incongruence inclinations (e.g., treadmill leveled & visual scene uphill) in a wide range of inclinations (−15° to +15°). We observed an approximately linear relation between the relative change in gait speed and the anticipated gravitational forces associated with the virtual inclinations. Mean relative gait speed increase of ~7%, ~11%, and ~17% were measured for virtual inclinations of +5°, +10°, and +15°, respectively (anticipated decelerating forces were proportional to sin[5°], sin[10°], sin[15°]). The same pattern was seen for downhill virtual inclinations with relative gait speed modulations of ~-10%, ~-16%, and ~-24% for inclinations of −5°, −10°, and −15°, respectively (in anticipation of accelerating forces). Furthermore, we observed that the magnitude of speed modulation following virtual inclination at ±10° was associated with subjective visual verticality misperception. In conclusion, visual cues modulate gait speed when surface inclinations change proportional to the anticipated effect of the gravitational force associated the inclinations. Our results emphasize the contribution of vision to locomotion in a dynamic environment and may enhance personalized rehabilitation strategies for gait speed modulations in neurological patients with gait impairments.

A pulse‐and‐glide ‐driven adaptive cruise control system for electric vehicle

As the adaptive cruise control system (ACCS) on vehicles is well-developed today, vehicle manufacturers have increasingly employed this technology in new-generation intelligent vehicles. Pulse-and-glide (PnG) strategy is an efficacious driving strategy to diminish fuel consumption in traditional oil-fueled vehicles. However, current studies rarely focus on the verification of the energy-saving effect of PnG on an electric vehicle (EV) and embedding PnG in ACCS. This paper proposes a pulse-and-glide-driven adaptive cruise control system (PGACCS) model which leverages PnG strategy as a parallel function with cruise control (CC) and verifies that PnG is an efficacious energy-saving strategy on EV by optimizing the energy cost of the PnG operation using Intelligent Genetic Algorithm and Particle Swarm Optimization (IGPSO). This paper builds up a simulation model of an EV with regenerative braking and ACCS based on which the performance of PGACCS and regenerative braking is evaluated; the PnG energy performance is optimized and the effect of regenerative braking on PnG energy performance is evaluated. As a result of PnG optimization, the PnG operation in the PGACCS could cut down 28.3% energy cost of the EV compared to the CC operation in the traditional ACCS which verifies that PnG is an effective energy-saving strategy for EV and PGACCS is a promising option for EV.

Design and Development of Braking and Wiring Systems in Go-Kart

This paper is aimed to calculate and numerically analyse the effectiveness of Disc brakes before and after manufacturing of full scale Go-kart. Disc brakes are developed over time to time for being a reliable method of decelerating and stopping a vehicle. There are different designs of disk brake systems for various applications. This review gives an in depth description of various geometries of the components and therefore the materials utilized in a disk brake system. In spite of all the involvements, there are still many operational issues associated with disc brakes that need to be understand during operations and resolved. There has been tons of research happening about these issues and at an equivalent time different methods are being proposed to eliminate or reduce them. One major purpose of this paper is to provide a comprehensive overview of all such developments.

Stress Analysis on an Automotive Coil Spring Driven on Flat, Uphill, and Downhill Road Surfaces

This study aims to analyze the stress that occurred on the automotive coil spring made of SAE 5160 carbon steel due to various types of road surfaces. The 60-second strain signals measured on a coil spring of a car being driven on a flat, uphill, and downhill road surface were used as the loads in these dynamic analyses. The analysis results showed that the maximum stress occurred on the inside of the spring in the second coil from the top. The results of this dynamic analysis also showed that the three types of road surfaces provided almost the same stress. The downhill road surface gave the highest stress, which was 0.622 GPa, followed by flat road (0.621 GPa) and uphill road (0.62 GPa). The reasons for this are the shifting of the vehicle load to the front wheels together with the braking effect when driving downhill.

A regulatory network involving Rpo, Gac and Rsm for nitrogen-fixing biofilm formation by Pseudomonas stutzeri

Biofilm and nitrogen fixation are two competitive strategies used by many plant-associated bacteria; however, the mechanisms underlying the formation of nitrogen-fixing biofilms remain largely unknown. Here, we examined the roles of multiple signalling systems in the regulation of biofilm formation by root-associated diazotrophic P. stutzeri A1501. Physiological analysis, construction of mutant strains and microscale thermophoresis experiments showed that RpoN is a regulatory hub coupling nitrogen fixation and biofilm formation by directly activating the transcription of pslA, a major gene involved in the synthesis of the Psl exopolysaccharide component of the biofilm matrix and nifA, the transcriptional activator of nif gene expression. Genetic complementation studies and determination of the copy number of transcripts by droplet digital PCR confirmed that the regulatory ncRNA RsmZ serves as a signal amplifier to trigger biofilm formation by sequestering the translational repressor protein RsmA away from pslA and sadC mRNAs, the latter of which encodes a diguanylate cyclase that synthesises c-di-GMP. Moreover, RpoS exerts a braking effect on biofilm formation by transcriptionally downregulating RsmZ expression, while RpoS expression is repressed posttranscriptionally by RsmA. These findings provide mechanistic insights into how the Rpo/Gac/Rsm regulatory networks fine-tune nitrogen-fixing biofilm formation in response to the availability of nutrients.

Increasing Energy Efficiency With Fuzzy Logic Control in FPGA-Based Electromagnetic Stirrer

In this study, a new field-programmable gate array (FPGA)-based electromagnetic stirrer system was developed allowing mixing on a single axis, and the energy efficiency of the system was increased with fuzzy logic control. The electromagnetic stirrer system was designed with three phases and each phase is fed with pulsewidth modulation (PWM) voltage with 120° phase difference. Ranked control of phases in the system used the FPGA structure in the myRIO® embedded system to determine the PWM signal production, increase intervals for phase frequencies, and rotation rate of the magnetic stir bar. In the system, to increase the energy efficiency with fuzzy logic control, the ARM® microcontroller structure in the myRIO® embedded system was used. Programming of the myRIO® embedded system was provided through the graphic-based LabVIEW <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">®</sup> software. In situations where the system is operated with 100% duty cycle, the force affecting the magnetic stir bar should be continuous and have fixed value until the next phase change. As a result, the magnetic stir bar performs more than 120° rotation and a braking effect of the force is observed. To resolve this situation, fuzzy logic control ensured operation of a different duty cycle without loss of speed of the stir bar. Thus, the energy efficiency of the system was increased with lower current and lower stimulation duration. Within the scope of this article, the experimental results obtained about the structure, control, and energy efficiency of the electromagnetic stirrer system are discussed in detail.

The motor brake of a compressor type

The accident rate in road transport remains very high and it is necessary to consider all the factors that affect this process to reduce it. In this regard, special attention should be paid to the process of long-term braking, the negative manifestations of which require the development of additional braking systems (retarding retarders) for vehicles operating in mountainous areas, primarily in the sphere of passenger transport. Transmission retarder brakes, which provide sufficient braking performance, have a number of disadvantages that hinder their use. The existing motor brakes-retarders show insufficient retardation and Kuban State Agrarian University conducted researches to improve their effectiveness. The compressor brake mode was experimentally studied after the theoretical analysis, in which an increased pressure was created in the inlet collector, and at the end of the compression stroke, the air from the cylinder was released through a special valve back into the system, which created the braking effect. The experiments have confirmed the possibility of a significant increase in the braking torque of the engine in the compressor brake mode, when both flaps are closed - the exhaust flap after the exhaust collector and the inlet collector before the carburetor, and compressed air is supplied to the inlet collector at different pressures. Then the braking torque increases in comparison with the engine braking more than 3 times.

Optimal operation of a rail lubrication device with respect to noise reduction and wheel/rail friction coefficient

During research work, three series of studies were performed to support the importance of using rail lubrication at tramway tracks in Budapest. The first task was to determine the noise reduction efficiency of automated rail lubrication: noise measurements were performed in case of lubricated rails with corrugations, non-lubricated rails with corrugations, grinded rails as well as grinded and lubricated rails. Once the conformity was determined, an additional task was to find the right lubricant. After the noise and braking effect tests of various lubricants, it was a legitimate need to determine the optimum lubricant application because the setting of the devices is based only on the experience of the Operator. Finally, the noise mitigation effect and the friction coefficient affecting the wheel/rail contact with different lubricant application settings were investigated simultaneously. It is important that the lubricant be applied in appropriate amount such that even the safe movement of the trams is guaranteed, but at the same time the noise reduction is satisfactory too. Based on the results, the authors make recommendations for the application of the rail lubrication devices.

Car braking effectiveness after adaptation for drivers with motor dysfunctions

Car braking effectiveness after adaptation for drivers with motor dysfunctions

Damping Behaviour of Multi-Walled Carbon Nanotubes Grafting on Carbon Fiber Reinforced Friction Material

&#x0D; &#x0D; &#x0D; An automobile's braking system plays an important role to control the vehicle at various operating speeds. At present, the brake friction industry is mainly focused on effectiveness of braking in addition to aesthetic considerations of an automobile. In this research, carbon fiber reinforced friction material is developed by grafting multi-walled carbon nanotubes functionalized (MWCNTS-F) on CF surface. The surface of CF is basically chemically inert and hydrophobic in nature and needs to be modified by grafting MWCNTS-F on its surface to increase hydroxyl or carboxyl groups. An attempt is made to improve the bonding strength between CF, polymer matrix and the remaining ingredients. Carbon fiber content after surface modification is varied in weight percentor wt% (2%, 3%, 4% and 5%) and mixed with the remaining ingredients of friction material. Composite sheets are prepared using hand lay-up method and characterized for damping, SEM, TGA and FTIR analysis. It is observed that MWCNTS-F grafted on CF 3 wt% possess good damping results. The results also reveal that, optimum selection of ingredients and surface treatment method on CF is the main reason for improvement of the composite’s interfacial adhesion and damping behavior.&#x0D; &#x0D; &#x0D;

Do Driver Characteristics and Crash Conditions Modify the Effectiveness of Automatic Emergency Braking?

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;Studies of automatic emergency braking (AEB) find that AEB-equipped vehicles are around half as likely to crash. This study examines whether driver characteristics and road and weather conditions modify this preventive effect of AEB.&lt;/div&gt;&lt;div class="htmlview paragraph"&gt;Toyota production data were merged with police reported crash files from eight U.S. states for crash years 2015 up to 2019 by 17-digit vehicle identification number (VIN). Using a case-control design, this study investigated the relationship of AEB presence with being a case vehicle in a system-relevant crash (the striking vehicle in front-to-rear crash; n=30,056) versus an AEB non-relevant control vehicle (the struck vehicle in a front-to-rear crash; n=62,820). The analysis was stratified by driver characteristics and by weather and road conditions. Logistic regression modeled the relationship, controlling for exposure (vehicle-days) and possible confounding factors. The resulting odds ratios for AEB equipment from the separate models were compared to determine if the effect of AEB presence was modified by the characteristic or condition of interest.&lt;/div&gt;&lt;div class="htmlview paragraph"&gt;Overall, AEB-equipped vehicles were 43% (p&amp;lt;0.001) less likely to be the striking (case) vehicle compared to non-equipped vehicles. However, the preventive effect of AEB was significantly lower among older drivers (over 65 years) compared to younger drivers; 29% less likely to be a striking vehicle (OR=0.71) versus 46% (OR=0.54), respectively. The effect of AEB was also lower in adverse weather conditions (rain, fog, snow) (OR=0.66) and on wet or snowy roads (OR=0.65), though these differences were not significant compared to clear weather and dry roads. The AEB effect was also lower among risk-taking drivers (alcohol-involved, speeding, or unrestrained) compared to non-risk-taking (OR=0.72 versus OR=0.59, respectively).&lt;/div&gt;&lt;div class="htmlview paragraph"&gt;AEB prevents crashes, regardless of driver characteristics and environmental conditions. This study suggests, however, that the size of the effect is smaller among older and risk-taking drivers, and in adverse weather and road conditions.&lt;/div&gt;&lt;/div&gt;

Indoor simulation test research on cumulative longitudinal displacement of rail based on force and displacement sensors data collection.

The train sometimes needs to brake frequently on the turnout, although the braking force does not exceed the limit resistance of fastener, cumulative displacement of rail occurs because of the long-term effect of the train brakes, thus, the relationship between the cumulative displacement of rail and the number of train braking actions should be explored. Aiming at the spring bar type III fastener, a 1:1 physical indoor simulation test was carried out, and an electromagnetic relay device was used to simulate the train load, force, and displacement sensors for data collection. Then a single load no more than the maximum resistance of fastener was applied to the rail end to explore the relationship between the number of loads and the rail cumulative deformation. The rail longitudinal cumulative displacement changes linearly in positive correlation with the number of load actions, and increases faster when the number of load actions is small. As the number of repeated loads increases, the above-mentioned relationship approximately and credibly obeys the power function distribution. Repeatedly applying load no more than the maximum longitudinal resistance of fastener to the rail, the existence of the rail cumulative displacement caused by frequent train braking can be demonstrated, and the relationship curve between the rail displacement and the number of loads can be obtained. Applying the fitting formula, the rail displacement after a specific number of loading times can be attained, and then referring to specific codes, we can determine whether it will exceed the safety limit.

Potential Effectiveness of Bicycle-Automatic Emergency Braking using the Washtenaw Area Transportation Study Data Set

In the United States, fatalities from vehicle–bicycle crashes have been increasing since 2010. A total of 857 cyclists were struck and killed in 2018 which is an increase from 623 fatalities in 2010. One promising countermeasure is Automatic Emergency Braking (AEB), which can help prevent and/or mitigate many vehicle–bicycle crashes. AEB is a vehicle-based system that can detect and mitigate an impending crash. The goal of this study was to elucidate U.S. vehicle–bicycle crashes and examine related factors to estimate AEB effectiveness. This study used a unique in-depth vehicle–bicycle crash study dataset collected under the collaboration of the Washtenaw Area Transportation Study (WATS) and the Toyota Collaborative Research Center conducted in southeast Michigan from 2011 to 2013. The WATS database provides in-depth investigations of vehicle–bicycle crashes in the United States. The characteristics of the WATS vehicle–bicycle crashes were validated against the Fatality Analysis Reporting System and the General Estimate System. The WATS database cases were examined to estimate the potential effectiveness of AEB to prevent or mitigate vehicle–bicycle collisions. In 60% of the WATS cases, cyclists were in the road for more than 1 s before impact. Assuming that a hypothetical AEB system requires a minimum of 1 s for detection and brake activation, these collisions would potentially be avoided or mitigated. However, for the remaining cases with less than 1 s of time to react (40% of cases), that AEB system would be challenged to avoid or mitigate the collision.

Car braking effectiveness after adaptation for drivers with motor dysfunctions

Abstract This article presents the results of measurements of the braking efficiency of vehicles adapted to be operated by drivers with motor dysfunctions. In such cars, the braking system is extended with an adaptive device that allows braking with the upper limb. This device applies pressure to the original brake in the car. The braking force and thus its efficiency depend on the mechanical ratio in the adapting device. In addition, braking performance depends on the sensitivity of the car’s original braking system and the maximum force that a disabled person can exert on the handbrake lever. Such a person may have limited power in the upper limbs. The force exerted by the driver can also be influenced by the position of the driver’s seat in relation to the handbrake lever. This article describes the research aimed at understanding the influence of the above-mentioned factors on the car braking performance. As a part of the analysis of the test results, a mathematical function was proposed that allows a parametric description of the braking efficiency index on the basis of data on the braking system, adaptation device, driver’s motor limitations, and the position of the driver’s seat. The information presented in this article can be used for the preliminary selection of adaptive devices to the needs of a given driver with a disability and to the vehicle construction.

Car braking effectiveness after adaptation for drivers with motor dysfunctions

Abstract This article presents the results of measurements of the braking efficiency of vehicles adapted to be operated by drivers with motor dysfunctions. In such cars, the braking system is extended with an adaptive device that allows braking with the upper limb. This device applies pressure to the original brake in the car. The braking force and thus its efficiency depend on the mechanical ratio in the adapting device. In addition, braking performance depends on the sensitivity of the car’s original braking system and the maximum force that a disabled person can exert on the handbrake lever. Such a person may have limited power in the upper limbs. The force exerted by the driver can also be influenced by the position of the driver’s seat in relation to the handbrake lever. This article describes the research aimed at understanding the influence of the above-mentioned factors on the car braking performance. As a part of the analysis of the test results, a mathematical function was proposed that allows a parametric description of the braking efficiency index on the basis of data on the braking system, adaptation device, driver’s motor limitations, and the position of the driver’s seat. The information presented in this article can be used for the preliminary selection of adaptive devices to the needs of a given driver with a disability and to the vehicle construction.

Electro-hydraulic Composite Emergency Braking System Based on Frequency Reconstruction Control

For four-wheel independently driven (FWID) electric vehicle (EV), in order to guarantee braking reliability, hydraulic braking system and motor anti-drag braking system are usually used at the same time. In this paper, a novel electro-hydraulic composite braking control strategy is given to solve the distribution problem of braking torque between hydraulic braking torque and motor anti-drag braking torque. The high-frequency part of the desired braking torque is distributed to the motor brake through a high-pass filter so as to fully utilize the fast response characteristics of the motor. Meanwhile, the low-frequency part of the desired braking torque is distributed to the hydraulic brake through a low-pass filter so as to reduce the load of the motor. The cost functions are designed to determine the cut-off frequency of low-pass and high-pass filters. Through the joint simulation of Matlab/Simulink and TruckSim, the braking effect of the electro-hydraulic composite braking is better than that of pure hydraulic braking with no motor to modulate the braking torque.

Front steering design guidelines formulation for e-scooters considering the influence of sitting and standing riders on self-stability and safety performance

E-scooters are a recent trend and are viewed as a sustainable solution to ease the first and last mile problem in modern transportation. However, an alarming rate of accidents, injuries, and fatalities have caused a significant setback for e-scooters. Many preventive measures and legislation have been put on the e-scooters, but the number of accidents and injuries has not reduced considerably. In this paper, the current design approach of e-scooters has been analyzed, and the most common range of design parameters have been identified. Thereafter, validated mathematical models have been used to quantify the performance of e-scooters and relate them with the safety aspects. Both standing and seated riders on e-scooters have been considered, and their influence on the dynamic performance has been analyzed and compared with the standard 26-in wheel reference safety bicycle. With more than 80% of the accidents and injuries occurring from falling or colliding with obstacles, this paper tries to correlate the dynamics of uncontrolled single-track vehicles with the safety performance of e-scooters. The self-stability, handling, and braking effect have been considered as major performance matrices. The analysis has shown that the current e-scooter designs are not as stable as the reference safety bicycle. Moreover, these e-scooters have been found unstable within the most common range of legislated riding velocity. The results corroborate with the general perception that the current designs of e-scooters are less stable, easy to lose control, twitchy, or wobbly to ride. Furthermore, the standing posture of the rider on the e-scooter has been found dangerous while braking to avoid any disturbances such as potholes or obstacles. Finally, the front steering design guidelines have been proposed to help modify the current design of e-scooters to improve the dynamic performance, hence the safety of the e-scooter riders and the surroundings.