Braking Time Research Articles

Оценка влияния параметров автомобилей на значение потока насыщения

Abstract. As a result of the changes that the car market has undergone over the past decades, a large number of various cars have appeared on the road, which are excellent primarily in design characteristics (length, width, height, weight, etc.), as well as dynamic (power, braking time, turning radius, etc.). When they are taken into account as the characteristics of a conventional car, incorporated into the initial model for calculating the parameters of a controlled intersection, it is possible to obtain variable data that will affect the final result — the value of the saturation flow. In order to determine the variability of the saturation flow values, taking into account certain parameters of a conventional car, the study presented in this article was carried out. The main objectives of the study were to analyze the composition of the traffic flow; determining the design and dynamic characteristics of the most common vehicles in the stream; establishing the parameters of a conditional car, determined by the calibrated one and calculating the saturation flux with subsequent comparison of the data obtained. When carrying out the research, the methods of field observations, analysis and mathematical calculation were used. The calculations were performed using a mathematical model used to determine the value of saturation flux when performing a turn, depending on the turning radius. In the study, this model was determined as the main one due to the fact that on many sections of the road network the turning radii change significantly, in contrast to the basic model, which depends on the lane width, which in most cases is standardized or does not change as much as turning radii. Based on the results of calculations, the variability of the ST values was obtained at 7% for the minimum value of the turning radius and 20% for the maximum value, which requires further research to assess the influence of the obtained results on the calculated parameters of the traffic light operation — the duration of the main ticks and the duration of the entire cycle, as well as on the parameters the transport stream itself when establishing new, refined work cycles.

Thermomechanical Behavior of Brake Drums Under Extreme Braking Conditions

Braking efficiency is characterized by reduced braking time and distance, and therefore passenger safety depends on the design of the braking system. During the braking of a vehicle, the braking system must dissipate the kinetic energy by transforming it into heat energy. A too high temperature can lead to an almost total loss of braking efficiency. An excessive rise in brake temperature can also cause surface cracks extending to the outside edge of the drum friction surface. Heat transfer and temperature gradient, not to forget the vehicle's travel environment (high speed, heavy load, and steeply sloping road conditions), must thus be the essential criteria for any brake system design. The aim of the present investigation is to analyze the thermal behavior of different brake drum designs during the single emergency braking of a heavy-duty vehicle on a steeply sloping road. The calculation of the temperature field is performed in transient mode using a three-dimensional finite element model assuming a constant coefficient of friction. In this study, the influence of geometrical brake drum configurations on the thermal behavior of brake drums with two different materials in grey cast iron FG200 and aluminum alloy 356.0 reinforced with silicon carbide (SiC) particles is analyzed under extreme vehicle braking conditions. The numerical simulation results obtained using FE software ANSYS are qualitatively compared with the results already published in the literature.

Robustness Analysis for Adaptive Model Predictive and Sliding Mode Controllers Regulating Longitudinal Tire Slip Ratio

This study aims to evaluate the robustness of Adaptive Model Prediction Controllers (AMPC) and First Order Sliding Mode Controllers (FOSMC) facing modelling uncertainties or external disturbances when used to track longitudinal tire slip ratio. Changing road conditions create uncertainties in the friction coefficient of the tire-road interface, and the uncertainty of mass is caused by over/under loads on the nominal mass of the vehicle. the external perturbations are generally linked to the angle of inclination of the road. The efficiency of the controllers, in terms of ensuring the minimum braking time in the face of uncertainties and perturbations, is evaluated by numerical simulation and detailed comparison.

CURRENT STATUS OF CONTROL STRATEGIES IN ENERGY RECOVERY SYSTEMS IN ELECTRIC VEHICLES

There is currently an increasing demand for electric vehicles that require greater autonomy and energy efficiency when driving them. Control strategies in energy recovery systems are crucial to optimize the amount of energy returned to the battery and to ensure safety and stability for the user. In this paper, active fault tolerant control systems (AFTC) and passive fault tolerant control systems (PFTC) with other specialized control strategies (Fuzzy Logic, Neural Networks and Perturbation Rejection Controllers) are compared with classical PID controllers.The results of the simulations show that, keeping the battery voltage constant, returns of about 12% of the battery charge capacity are achieved while the braking time of the vehicles is reduced.

Permitted speed decision of single-unit trucks with emergency braking maneuver on horizontal curves under rainy weather.

Under adverse weather conditions, visibility and the available pavement friction are reduced. The improper selection of speed on curved road sections leads to an unreasonable distribution of longitudinal and lateral friction, which is likely to cause rear-end collisions and lateral instability accidents. This study considers the combined braking and turning maneuvers to obtain the permitted vehicle speed under rainy conditions. First, a braking distance computation model was established by simplifying the relationship curve between brake pedal force, vehicle braking deceleration, and braking time. Different from the visibility commonly used in the meteorological field, this paper defines "driver’s sight distance based on real road scenarios" as a threshold to measure the longitudinal safety of the vehicle. Furthermore, the lateral friction and rollover margin is defined to characterize the vehicle’s lateral stability. The corresponding relationship between rainfall intensity-water film thickness-road friction is established to better predict the safe speed based on the information issued by the weather station. It should be noted that since the road friction factor of the wet pavement not only determined the safe vehicle speed but also be determined by the vehicle speed, so we adopt Ferrari’s method to solve the quartic equation about permitted vehicle speed. Finally, the braking and turning maneuvers are considered comprehensively based on the principle of friction ellipse. The results of the TruckSim simulation show that for a single-unit truck, running at the computed permitted speed, both lateral and longitudinal stability meet the requirements. The proposed permitted vehicle speed model on horizontal curves can provide driving guidance for drivers on curves under rainy weather or as a decision-making basis for road managers.

КОНЦЕПЦІЯ ОЦІНКИ ГАЛЬМІВНОЇ ЕФЕКТИВНОСТІ ВАНТАЖНИХ ПОЇЗДІВ ЗА РЕЗУЛЬТАТАМИ ЕКСПЕРИМЕНТАЛЬНИХ ДОСЛІДЖЕНЬ У РОЗРІЗІ ВИМОГ ГОСТ 34434-2018

The approach of experimental study of the freight trains braking efficiency using computer simulation based on the implementation of the simulation model in the form of a differential equation of the wagon motion during braking, is proposed. The methodology of experimental studies is based on universal formulas for power-law dependences of braking parameters. The braking efficiency is evaluated by the use of computer software packages written in VBA (Visual Basic for Application) in Excel. The software package al-lows you to increase the automation of testing, the accuracy of calculations, to reduce the time for testing, and also minimize the number of errors caused by the human factor. The presented methodology significantly extends the number of parameters of the braking process used to analyze the braking efficiency of a freight train based on the results of running braking tests: actual values of braking coefficients; braking distances of a freight train not only on the site, but also on normalized gradient descents for a given number of wagons in the train, taking into account the increase in the braking force along the wagons in the train formation; actual values of wheel and rail adhesion coefficients during braking; the deceleration of the freight wagon and the train during braking, as well as the braking time. Examples of computational and experimental studies of a freight train with tread brake are given. A comparative analysis of experimental and computational studies demonstrates sufficiently satisfactory matching of their results. Key words: freight train, braking distance, braking speed, braking coefficient, increase in braking force, mathematical model, trend line, braking wave.

MINIMIZATION OF ELECTRICAL CONSUMPTION OF A FREQUENCY-REGULATION INDUCTION MOTOR WITH A FAN LOAD IN START-BRAKING REGIMES

Purpuse. To minimize the total power consumption in start-braking regimes by a three-phase squirrel-cage frequency-regulated induction motor, loaded a centrifugal fan (or smoke exhauster), and also to obtain analytical dependencies for calculating the optimal durations of acceleration and deceleration times, corresponding to minimizing the total energy consumption of this motor in start-braking regimes with the indicated type of load. Metodology. Based on the methods of calculus of variations and numerical solution of non-linear differential equations, the quasi-optimal type of trajectories of speed change (tachograms) of the motor with the considered load in start-braking regimes is determined. Using the methods of mathematical analysis and similarity, the acceleration and deceleration times of an induction motor with a fan load were optimized for different (linear, parabolic and quasi-optimal) types of tachograms. Using the method of computer simulation, the energy consumption in the start-braking regimes of an induction motor with the indicated load for these types of tachograms was quantified. Results. Refined analytical dependencies are obtained for calculating the consumed active power and energy in start-braking regimes by a frequency-regulated induction motor with a fan load for the mentioned various types of tachograms. Analytical optimization of the consumption of active energy of this motor in start-braking regimes has been carried out. The change at the optimal durations for the starting-braking regimes and the corresponding it’s total energy consumption of the motor with varying the maximum value of the motor speed in these regimes has been researched. A quantitative assessment of transient electromechanical and energy processes in the considered motor with a fan load has been carried out. For this motor, as applied to the non-regenerative version of the static frequency converter, a scalar automatic control system is proposed, by means of which the motor accelerates with a constant rotor flux linkage with a given (linear, parabolic or quasi-optimal) speed trajectory and brakes on freewheel. The expected annual saving of active energy by an induction motor, loaded with a smoke exhauster, in starting and braking regimes, achieved by optimizing the form of the tachograms and the duration of the acceleration and deceleration times, is determined. Originality. Analytical dependencies are obtained for calculating the optimal durations of the acceleration and deceleration times of an induction motor with a fan load, corresponding to minimizing the energy consumption of this motor in start-braking regimes. The "U"-shaped form of dependences of the total energy, consumed during acceleration (or the total generated energy during braking) of the induction motor in function the duration of the deceleration (or braking) times is established. An analytical dependence is obtained for changing the speed of a motor loaded by a fan or a smoke exhauster during the freewheel braking regime, and an analytical expression is proposed for determining the duration of the indicated braking time. Practical value. On the example of an induction motor loaded by a smoke exhauster, the possibility of saving the total energy consumption in start-braking regimes was identified: from 77 to 90 % – due to the use of the proposed quasi-optimal tachogram and the use of practically realizable optimal acceleration and deceleration times, and also in the amount of 10 % – through the transition from freewheel braking to regenerative braking. Figures 6, tables 6, references 22.

Minimization of power and energy consumption of mechatronic drives in robotics and technological equipment

The maximum instantaneous power consumption of robot drives determines the requirements for the energy supply system and the dimensions of the machine. For numerous machines, there are no technological restrictions on the types of applied motion laws and their numerical characteristics i.e. maximum speeds and accelerations. The type of the motion law and especially its parameters are traditionally determined according to the preferences of the design engineer without any justification, though some-times restrictions on maximum accelerations or speeds are considered. The restrictions on maximum accelerations are related to ensuring the strength and accuracy of the drive, and the restrictions on maximum speeds are related to the safety of personnel in the workplace. The motor power is selected according to the maximum value of the instantaneous power and thermal load, which depends on the duration of switching on. The article analyzes the ways of minimizing of this maximum (peak) of instantaneous power inside the cycle for different laws and different loads. The main parameter by which the maximum (peak) power is minimized for all types of laws is the acceleration and braking times. On the example of the most common motion laws, the dependence of instantaneous power and energy consumption on accelerating time and braking time for various types of loads are studied. In this article, the dependence of instantaneous power and energy consumption on accelerating time and braking time for various types of loads are studied on the example of the most common motion laws. The research results are intended to create a design technique for drives of modern equipment.

A novel method for determining fixed running time in operating electric train tracking optimal speed profile

<span lang="EN-US">Tracking the optimal speed profile in electric train operation has been proposed as a potential solution for reducing energy consumption in electric train operation, at no cost to improve infrastructure of existing Metro lines as well. However, the optimal speed profile needs to meet fixed running time. Therefore, this paper focuses on a new method for determining the fixed running time complied with the scheduled timetable when trains track the optimal speed profile. The novel method to ensure the fixed running time is the numerical-analytical one. Calculating accelerating time ta, coasting time tc, braking time tb via values of holding speed vh, braking speed vb of optimal speed profile with the constraint condition: the running time equal to the demand time. The other hands, vh and vb are determined by solving nonlinear equations with constraint conditions. Additionally, changing running time suit for each operation stage of metro lines or lines starting to conduct schedules by the numerical-analytical method is quite easy. Simulation results obtained for two scenarios with data collected from electrified trains of Cat Linh-Ha Dong metro line, Vietnam show that running time complied with scheduled timetables, energy saving by tracking optimal speed profile for the entire route is up to 8.7%, if the running time is one second longer than original time, energy saving is about 11.96%.</span>

Tractor-trailer-train braking time sequence detection based on monocular vision

The tractor-trailer-train at the braking process prone to braking instability caused by asynchronous braking between the shafts. With respect to the lack of intelligent detection of Braking Time Sequence (BTS), a non-contact dynamic detection scheme of intelligent vehicle BTS is proposed. Based on the monocular vision principle, the edge markers of tractor-trailer train tires are identified, and the tire slip rate is solved. The noise reduction of the collected image is processed. The marker area is obtained by Blob analysis. This region at the image to be matched is identified by the template matching algorithm based on contour. The camera is calibrated by Zhang’s calibration method. In order to verify the effectiveness of the detection scheme, the real vehicle test was carried out. The test results show that the error of slip rate solution is below 4.2%.

Testing the Impact of Braking Algorithm Parameters on Acceleration and Braking Distance for a Suspended Monorail with Regard to Acceptable Travel Speed in Hard Coal Mines

Increasing the maximum speed limit of suspended monorails, which became a very popular means of auxiliary transport, is one of the aspects of improving the efficiency of work in underground coal mines. It is especially important to enable higher (than allowed by the law) travel speed, when moving the crew to and from the workplace, which is often very distant from the shaft, and can take more than one hour of travel. Increasing this speed will make it possible to extend the effective working time of miners, which should have a positive impact on the economics of the mine. However, driving at a higher speed is also associated with increased risk of a negative impact of dynamic overload to people, e.g., during emergency braking of the suspended monorail. The concept of sequential emergency braking was developed in order to avoid excessive deceleration affecting passengers and the operator of the monorail, as well as to minimize the dynamic loads acting on the rail suspensions and on the roadway support frames, which could cause serious accidents. The developed assumptions with regard to the new method of braking are innovative in the area related to hard coal mining, where there are currently no such solutions. According to the principles of the developed concept, the total braking force was divided into two stages. The activation of the second stage depends on the deceleration measured after the time delay from activation of the first stage of braking. We present the results of the numerical simulations, which aimed to analyze the impact of changing the parameters of the braking algorithm on the braking deceleration, the braking time, and the braking distance. The possibility of changing the braking force and downward emergency braking on a high inclination angle were also taken into account during the numerical simulations. Use of the developed emergency braking algorithm enables the optimization of this process at a higher speed than is currently used. This aspect is also very important in increasing the safety for people travelling at a higher speed limit. The numerical simulations provide knowledge for safety in terms of the dynamic overload during emergency braking, without injury risk to miners or damage to equipment.

Thermal stress analysis of disc brake using analytical and numerical methods

This article presents study of the thermal stress development in brake disc and the associated life cycle of the disc. The thermal stress analysis of disc brake under the first brake application and the influences of thermal loads on stress development of the disc have been investigated. The temperature distribution was conducted as a function of disc thickness and braking time. The study was done on the disc brake of Sports Utility Vehicle with a model of DD6470C. Partial solution approach was used to solve analytical temperature distribution through the thickness. The model was done using representative areas of the disc exposed to high temperature whose distribution result was obtained as a function of disc thickness and braking time. The solutions of coupled thermal transient fields and stress fields were obtained based on thermal-structural coupled analysis. Based on the model developed for the study, the positions of high and low stress formations were investigated, and it has been observed that thermal stress and temperature gradient show similar behavior through the thickness of disc. Generally, high temperature and stress components were found on the rubbing surfaces of the disc.

PENGARUH PEMILIHAN KAMPAS REM PADA RODA DEPAN HONDA SONIC 150R

Brakes are an important element in a vehicle that serves to reduce and stop the vehicle, allow the vehicle to park in an uneven place and a tool that ensures the safety and security of the driver. One of the important components of the brake system is the brake lining. People are often confused in choosing brake pads. The purpose of this study was to determine the effect of local product brake lining grades, genuine parts, and racing on the braking distance and time and which brake lining is better to use. This test was carried out by testing the front brake braking on a flat and straight road on a Honda Sonic 150r with a brake lever pressure of 3 kg at every speed of 30km/hour, 40km/hour, 50km/hour, and 60km/hour by testing 3 times on each canvas. brakes and speed. The test results show that racing grade brake linings are the best to use.Keywords: brake pads, distance, time.

Train Braking Time Variations Changing the Pressurized Air Temperature

Braking time in a moving train at standard speeds has become a critical variable that increasingly concerns the industry. The present paper discusses the possible option of temperature variation to cut down the response time of the whole pneumatic braking system in a train installation. A pneumatic system, considered equivalent to the system existing in a real train, was experimentally analyzed to account for the time and characteristics of a sonic pressure wave moving in the pipes. The available system behavior was compared for two different air temperatures. The obtained results point to a relevant temperature effect on the pressure wave transmission, which may promote time or distance shortening in a standard braking process. Although in the experimental campaign only two initial temperatures could be set, the study shows a possible research path for future improvements. A parallel theoretical calculation corrected by the effect of the relevant elements in the pipes was performed to allow a comparison with the experiments.

Energy-efficient speed profile: An optimal approach with fixed running time

Tracking the optimal speed profile in electric train operation has been proposed as an efficient and feasible solution for not only reducing energy consumption, but also no at costs to upgrading the existing railway systems. This paper focuses on finding the optimal speed profile based on Pontryagin's maximum principle (PMP) while ensuring the fixed running time, and comparing energy saving levels in the cases of applying or not applying PMP. The way to determine the fixed running time also differs from works published is to calculate the total trip time equal to scheduled timetable exactly. Calculating accelerating time t a , coasting time t c , braking time t b via values of maximum speed v h , braking speed v b of optimal speed profile. The other hands, v h and v b are determined by solving nonlinear equations with constraint condition: the running time equal to the demand time. Simulation results with data collected from electrified trains of Cat Linh-Ha Dong metro line, Vietnam show that energy reduction for the entire route when PMP utilization is up to 8.7% and running time complied with scheduled timetables.

Brake Pad Characteristics of Natural Fiber Composites from Coconut Fibre and Wood Powder

The aim of the research is to develop brake pad of natural fibre composite from coconut fiber waste and wood powder. The characteristics of hardness, braking time and wear compared to the commercial brake pad had been studied. Test samples were produced by varying content of coconut fiber from 0 - 40% weight, wood powder content from 40% - 0 weight with 10% intervals. The percentage of polyester resin was made constant. The process of mixing ingredients started from filtering coconut fiber and wood powder using a filter with mesh size 40 μm. Then, the materials combined with certain composition into a container and stirred until evenly mixed. The composite poured into the mold was design appropriate the motorcycle disc brake pad dimensions. The test results of natural fiber composites on brake pads showed different characteristic values on hardness, wear, and braking time tests.

Thermomechanical and Tribological Properties of SiC/Gr Reinforced Hybrid Aluminum Composite for Disc Brake Application

The disc brake motorcycle material has been developed by using aluminium matrix composite (AMC) reinforced with matrix particulate ceramic. The composite has many advantages: lightweight, high re-sistance to wear, and controllable strength by adjusting the reinforcement materials percentage. The main issue is the environmental factor that influences the surface properties of the disc. The research aims to study thermomechanical and tribology characteristics to determine the effect of the environmental factor on the composite's wear-out rate. The disc is made from matrix Al7Si6Mg9Zn composite matrix with 10% SiC and 10% graphite (v/v). The disc is produced by squeeze casting method and heated for 4 hours at 180 °C as artificial aging heat treatment. Thermomechanical characteristics are carried out by observing the temperature changes when a load is introduced to the disc. The pin-on-disc method is applied at three different speeds (60, 80, and 100 rpm) under the wet and dry surface on the disc for observing the tribo-logical properties. Thermomechanical characteristics of the disc are average braking time is 3.72 seconds, where the average braking distance is 515.8 cm at speed 40 km/hour with the average temperature of 46.12 °C. The wear-out rate results are steady, where the highest wear out rate for the dry surface is 0.725 mm3/N.m and 6.133 mm3/N.m for the wet surface at 100 rpm.

Phase-Specific Verbal Cue Effects on Countermovement Jump Performance.

Krzyszkowski, J, Chowning, LD, and Harry, JR. Phase-Specific Verbal Cue Effects on Countermovement Jump Performance. J Strength Cond Res 36(12): 3352-3358, 2022-The aim of this study was to determine whether countermovement vertical jump (CMVJ) phase-specific cues can improve jump performance and phase-specific force-time characteristics. Twenty-nine subjects (14 males and 15 females) performed 15 total CMVJ trials (5 per condition) while being provided with a control and phase-specific (unloading phase and eccentric braking phases) foci of attention. Jump height, reactive strength index-modified, countermovement depth, time-to-takeoff, and CMVJ subphase force-time characteristics were compared between each phase-specific verbal cues and the control condition using paired samples t-tests ( α = 0.05) and Cohen's d effect sizes ( d ; large >1.2). Female ( d = 0.242; p = 0.012) and male ( d = 1.96; p = 0.047) subjects achieved greater jump heights in the control condition compared with the unloading phase condition. Females demonstrated a faster unloading phase, less unloading force, greater unloading yank, and greater braking force during the unloading condition, as well as greater eccentric braking force during the eccentric braking condition compared with the control condition ( p ≤ 0.014; d ≥ 0.242). Males exhibited less body mass unloading, greater unloading yank, faster eccentric braking time, greater eccentric braking force, and greater eccentric braking yank for both the unloading and eccentric braking conditions compared with the control condition ( p ≤ 0.047; d ≥ 0.196). Collectively, these results suggest that phase-specific foci of attention do not acutely improve jump performance but can enhance phase-specific force-time characteristics in recreationally active individuals. Specifically, practitioners should consider using an eccentric braking phase instruction for individuals need to improve eccentric braking force generation.

Development of AEB control strategy for autonomous vehicles on snow-asphalt joint pavement

ABSRACT An autonomous emergency braking (AEB) algorithm for snow-asphalt joint pavement is proposed. Based on machine vision and kinetic analysis, we realize the identification of road information, including the road type, slope, and road section lengths. A new safety model, the reference velocity model, is proposed to solve the problem of determining the braking time on the joint pavement to achieve collision avoidance. In the asphalt section, we design the desired deceleration considering the comfort and safety, while in the snow section, we use the estimated maximum deceleration that the pavement can provide. To meet the desired deceleration requirement, we choose a single-neuron proportion integration differentiation (PID) controller with a Kalman filter. The joint simulation with CarSim and Simulink shows that the host vehicle successfully realizes collision avoidance in various working conditions and verifies the proposed AEB algorithm. Benefitting by the recognition of the forefront road conditions, our proposed model performs better than the traditional AEB model.

Application of neural networks in predictions of brake wear particulate matter emission

According to the World Health Organization, air pollution with PM10 and PM2.5 (PM-particulate matter) is a significant problem that can have serious consequences for human health. Vehicles, as one of the main sources of PM10 and PM2.5 emissions, pollute the air and the environment both by creating particles by burning fuel in the engine, and by wearing of various elements in some vehicle systems. In this paper, the authors conducted the prediction of the formation of PM10 and PM2.5 particles generated by the wear of the braking system using a neural network (Artificial Neural Networks (ANN)). In this case, the neural network model was created based on the generated particles that were measured experimentally, while the validity of the created neural network was checked by means of a comparative analysis of the experimentally measured amount of particles and the prediction results. The experimental results were obtained by testing on an inertial braking dynamometer, where braking was performed in several modes, that is under different braking parameters (simulated vehicle speed, brake system pressure, temperature, braking time, braking torque). During braking, the concentration of PM10 and PM2.5 particles was measured simultaneously. The total of 196 measurements were performed and these data were used for training, validation, and verification of the neural network. When it comes to simulation, a comparison of two types of neural networks was performed with one output and with two outputs. For each type, network training was conducted using three different algorithms of backpropagation methods. For each neural network, a comparison of the obtained experimental and simulation results was performed. More accurate prediction results were obtained by the single-output neural network for both particulate sizes, while the smallest error was found in the case of a trained neural network using the Levenberg-Marquardt backward propagation algorithm. The aim of creating such a prediction model is to prove that by using neural networks it is possible to predict the emission of particles generated by brake wear, which can be further used for modern traffic systems such as traffic control. In addition, this wear algorithm could be applied on other vehicle systems, such as a clutch or tires.