High-speed Car Research Articles

An Optimized Dynamic Traffic Control System using OpenCV

Abstract: This study delves into a web-based platform designed to apprehend speeding vehicles. It harnesses the capabilities of OpenCV, a robust computer vision library, to accurately detect high-speed cars. Furthermore, the system integrates a specialized model for identifying vehicles deviating from their designated lanes, thereby fostering safer road conditions. To streamline the process of vehicle identification and potential ticket issuance, it incorporates automatic license plate recognition through Azure Cognitive Services. By amalgamating these advanced technologies, the proposed system offers a comprehensive solution for realtime traffic monitoring and regulation enforcement, with the overarching goal of enhancing road safety and traffic management.

Dual-Frequency Signal Enhancement Method of Moving Target Echoes for GNSS-S Radar

The GNSS-S radar utilizes the signals of a global navigation satellite system (GNSS) to carry out target detection. Due to the very low power of GNSS signals, long-term accumulation is needed to improve the gain of the echo signals. However, when it is used for moving object detection, the random movement of the target will cause residual Doppler frequency after the echoes are correlated and compressed through the direct signal. The residual Doppler frequency will cause two problems: on the one hand, the signal coherence will deteriorate, affecting the coherent accumulation gain; on the other hand, the amplitude of the signal after compression will decrease due to the sensitivity of GNSS signals to Doppler frequency. Therefore, how to increase the signal amplitude and eliminate the phase fluctuation caused by the Doppler frequency shift in the GNSS echoes of moving targets is an important issue for GNSS-S radar to detect moving targets. This paper proposes a dual-frequency GNSS echo enhancement method that uses the dual-frequency signals transmitted by the GNSS satellites to enhance and regularize the target echo. First, the phase relationship model of the GNSS dual-frequency echo is constructed, and the phase difference is made to the compressed dual-frequency echo signal to obtain the differential phase without fluctuation; then, the amplitudes of the dual-frequency echo signals are added together; and finally, a new signal with enhanced amplitude and consistent phase is constructed by using the dual-frequency additive amplitude and differential phase, and the long-term coherent accumulation of the signal is carried out, which can improve the processing gain of the weak echo signal of the moving target. The simulation and field experiments show that this method makes full use of the energy of the GNSS dual-frequency signal and eliminates the phase fluctuation in the echo signal of the moving target so that the compressed signal energy remains consistent in the slow-time dimension. After long-term coherent accumulation, the echo SNR was greatly improved, which enabled the detection of two high-speed cars by GNSS-S radar in the experiment.

Deep Reinforcement Learning Car-Following Model Considering Longitudinal and Lateral Control

The lateral control of the vehicle is significant for reducing the rollover risk of high-speed cars and improving the stability of the following vehicle. However, the existing car-following (CF) models rarely consider lateral control. Therefore, a CF model with combined longitudinal and lateral control is constructed based on the three degrees of freedom vehicle dynamics model and reinforcement learning method. First, 100 CF segments were selected from the OpenACC database, including 50 straight and 50 curved road trajectories. Afterward, the deep deterministic policy gradient (DDPG) car-following model and multi-agent deep deterministic policy gradient (MADDPG) car-following model were constructed based on the deterministic policy gradient theory. Finally, the models are trained with the extracted trajectory data and verified by comparison with the observed data. The results indicate that the vehicle under the control of the MADDPG model and the vehicle under the control of the DDPG model are both safer and more comfortable than the human-driven vehicle (HDV) on straight roads and curved roads. Under the premise of safety, the vehicle under the control of the MADDPG model has the highest road traffic flow efficiency. The maximum lateral offset of the vehicle under the control of the MADDPG model and the vehicle under the control of the DDPG model in straight road conditions is respectively reduced by 80.86% and 71.92%, compared with the HDV, and the maximum lateral offset in the curved road conditions is lessened by 83.67% and 78.95%. The proposed car following model can provide a reference for developing an adaptive cruise control system considering lateral stability.

CFD Analysis on the Effect of Vortex Generator on Sedan Car using ANSYS Software

Nowadays, the demand for a high-speed car increases in which vehicle stability and fuel economy are the primary concern. The vehicle's aerodynamics plays a crucial role as it influences the overall performance of the vehicles. In the exploration of car aerodynamics, it involves studying various forces that act on a car while moving on the road, i.e., drag force, lift force. The leading causes of aerodynamic drag for automotive vehicles are the flow separation at the vehicles' rear end. By reducing the drag force, it is possible to increase the fuel economy. The research is focused on the effect of a vortex generator (VG) on a sedan car aerodynamics. The objective is to simulate fluid flow analysis for a sedan car that uses VG and without VG, to assess the effect of a different configuration of VG and the impact of a varying number of VG mounted on a sedan car in terms of flow pattern development and coefficient of drag (Cd). This study is conducted using two identical sedan car models, i.e., with VG and without VG. The flow around the vehicle has been considered incompressible. It is obtained by solving the incompressible form of the Reynolds Navier-Stokes (RANS) equations combined with the k-ε turbulence model. The simulation is run for different configuration of VG that acquire different radius of fillet, i.e., VG-1 (5 mm), VG-2 (30 mm) and VG-3 (50 mm) and for different number of VG that is mounted on a sedan car, i.e., 0 VG, 1 VG, 3 VG, 5 VG, 7 VG, and 9 VG. The data and results taken from this simulation show that the smallest fillet radius of VG, i.e., VG-1 (5 mm), is the best VG to be used on a sedan car. The results also show that, as the number of VGs increases, the drag coefficient is decreased. Hence, the best number of VGs to be used on a sedan car are nine VGs.

Neural Network Algorithm for Stabilizing Mechanized Systems

The article describes an experimental model of stabilization of a mechanized system. The following are shown: a skate; an element of the program code; an algorithm for stabilizing a proportional-integral-differential controller (PID). The experimental model uses the calculation and adjustment of the regulator according to the Ziegler-Nichols method. For the case of applying the neural network approach to the search for equilibrium, the Hopfield neural network is used. The technology of calculating the balancing of the values of the coefficients: proportional, integral, differential components are described. The design of the rolling system is described. The experimental model is designed to identify the balancing range of the rolling system of small-diameter balls. The experimental module balances the ball at a distance of 4.5 to 7 cm (SW-range). The shortcomings of the experimental model of stabilization of the mechanized system are revealed. The analysis of experimental studies of spacecraft stabilization is carried out. It is determined that it is advisable to use the mathematical tools of the sixth-order Butterworth polynomial in the training of a neural network. Complex neural network calculations make it possible to calculate the stabilization coefficients of the spacecraft when the coordinate system does not coincide with the axes of inertia. An overview of the authors ' research on the use of intelligent quality control systems for the production of medicines is given. An overview of neural network solutions for stabilizing the turning angle of high-speed cars is given. The expediency of selecting the stabilization coefficients of a proportional-integral-differential regulator by a trained neural network for various rolling ranges is proved.

Research on the effect of car’s roll motion on the aerodynamic characteristics of high-speed car

The main purpose of this study is to study the aerodynamic mechanism of periodic roll motion of car body and provide engineering reference for car design and safety evaluation. A simplified roll motion model is established based on a real car model. The two-wheel centerline of the left-wheel symmetrical section is considered as the roll axis, and the overset mesh method was used to model the sinusoidal roll motion of the car. According to the experimental data, the frequency and maximum roll angle were set to be 10 Hz and 2.2°, respectively. A transient numerical solver based on the detached-eddy simulation method is employed. The accuracy of the numerical method is validated by means of the wind tunnel test. Due to the asymmetry of the movement, the aerodynamic change of the roll motion was obvious. It is found that the roll motion is closely related to the aerodynamic characteristics of the car. Because of the hysteresis effect, the phase of aerodynamic force on the car shifts and the most dangerous position of the car is obtained. In addition, the aerodynamic differences of the car parts are found, and the wake is analyzed in detail.

Investigation of the wear of asphalt concrete pavement taking into account the influence of temperature, moisture of the pavement and the presence of an aggressive environment

Abstract. The emergence of a large number of modern high-speed cars with improved dynamic characteristics and an increase in the share of cars, especially large load capacity, have significantly accelerated the destruction of asphalt roads. Plastic deformations, tracks and cracks are more and more often observed on asphalt concrete pavements of roads, their wear is accelerated. As a result, the transport and operational condition of roads deteriorates, the speed of traffic decreases, the cost of road transport increases, and increasing costs are required for road repairs. Thus, the conditions of traction of the wheels of the car with the road surface are influenced by the service life of the coating, traffic intensity, the amount of harmful emissions of industrial enterprises and climatic factors. At the same time uneven change of conditions of coupling in cross and longitudinal profiles of the highway comes to light. Analyzing the natural and climatic factors, we can establish that different weather conditions have different effects on the condition of the road surface. In summer, the condition of the surface is dry and clean, so the driving conditions are safe. Taking into account all the factors that lead to the destruction of the coating with the formation of residual deformations and irreversible changes, requires the study of wear of the coating surface. he wear of the coating largely depends on the friction force in the area of contact of the tire with the surface of the coating, the type of tires and the pressure in the tires. But the random nature of changes in the intensity and composition of traffic, seasons, temperature, humidity, rainfall affects the amount of wear over a period of operation of the road surface. The presence of water or solutions in the pores of the coating leads to the separation of mineral particles from the layer under the action of impact force from the wheels of vehicles. It is experimentally established that the wear of asphalt concrete in the dry and wet state increases with increasing temperature. One of the main types of damage to road surfaces is their premature wear under the influence of vehicle wheels, in combination with changing weather conditions. Analyzing the natural and climatic factors, we can establish that different weather conditions have different effects on the condition of the road surface. The article considers the influence of temperature, humidity and the presence of solutions of chloride anti-icing materials on the process of abrasion of asphalt pavement in the autumn-winter period. Occurrence of big differences of temperature and humidity accelerates processes of aging of materials from which layers are made, influencing their durability and wear resistance.

Drag reduction by application of aerodynamic devices in a race car

In this era of fast-depleting natural resources, the hike in fuel prices is ever-growing. With stringent norms over environmental policies, the automotive manufacturers are on a voyage to produce efficient vehicles with lower emissions. High-speed cars are at a stake to provide uncompromised performance but having strict rules over emissions drives the companies to approach through a different route to keep the demands of performance intact. One of the most sought-after ways is to improve the aerodynamics of the vehicles. Drag force is one of the major setbacks when it comes to achieving high speeds when the vehicle is in motion. This research aims to examine the effects of different add on devices on the vehicle to reduce drag and make the vehicle aerodynamically streamlined. A more streamlined vehicle will be able to achieve high speeds and consequently, the fuel economy is also improved. The three-dimensional car model is developed in SOLIDWORKS v17. Computational Fluid Dynamics (CFD) is performed to understand the effects of these add on devices. CFD is carried out in the ANSYS™ 17.0 Fluent module. Drag Coefficient (CD), Lift Coefficient (CL), Drag Force and Lift Force are calculated and compared in different cases. The result of the simulations was analyzed and it was observed that different devices posed several different functionalities, but maximum drag reduction was found in the case of GT with spoiler and diffuser with a maximum reduction of 16.53%.

To the question of action on the rods lying on elastic foundation, inertial load with a variable speed of its movement

A method for calculating the rods on elastic foundation under the inertial load action when it moves at a variable speed is proposed. Test problems about a force or load movement with variable speeds along a hinged beam and about the movement with a high-speed railway car deceleration along a track section modeled by a hinged supported beam of great length on an elastic foundation are considered. The selection of the elastic foundation material of the rail track determines the dynamics of the high-speed railway car in different modes of its movement. To construct the methodology, the previously proposed by the author of the article solutions are used: a step-by-step procedure for solving the problems of unsteady dynamics of structures and the method of “nodal accelerations” to take into account the action on structures of a moving inertial load.

Design and analysis of disc brake system in high speed vehicles

Brakes are the most important component of any automobile. Brakes provide the ability to reduce or bring automobile to a complete stop. The process of braking is usually achieved by applying pressure to the brake discs. The main objective of this research paper is to propose an appropriate design and to perform analysis of a suitable brake rotor to enhance the performance of the high-speed car. The design of the brake disc is modelled using Solid works and the analysis is carried out using Ansys software. The analysis has been conducted by considering stainless steel and grey cast iron using same brake rotor design so that optimal choice of brake disc can be considered. The analysis considered involves static structural analysis and steady state thermal analysis considering specific parameters on brake rotor to increase the life of brake rotor. From the analysis it is found that the performance and life of disc brake depends upon heat dissipation. From the analysis results it can be concluded that grey cast iron has performed better as compared to stainless steel as this material has anti-fade properties which improves the life of the brake rotor.

Simulation of Fluid Flow Through Sedan Car YRS 4 Doors with Speed Variation using CFD

Aerodynamic forces that occur around the vehicle must be considered since it involves safety, ergonomic, and fuel consumption. To reduce fuel consumption, the vehicle should be built as aerodynamic as possible to minimize drag forces. The vehicle becomes unstable at high speed due to increasing lift force. To balance the vehicle at high speed, a downforce should be generated to keep the tires attached to the road surface. Each type of car has a various value of aerodynamic force due to its design, dimension, and cross-section area. The characteristics of streamflow around the car are discussed in this paper. This research simulated 2D sedan car YRS 4 Doors in the steady condition in various velocities, i.e. 23 m/s, 26 m/s, and 40 m/s. This simulation used the Quad Pave mesh model and run in k-ε implicit turbulence model. The characteristics could be observed from the qualitative and quantitative data. The quantitative data used as measurable data were Coefficient of Pressure (CP) and Drag Coefficient (CD). Quantitative data was shown to outline a better visual explanation of the streaming characteristic. The qualitative data used in this paper are path lines, velocity vectors, and contours. The high-velocity stream results in a low value of CP. When the fluid flowed at high speed through a surface, it had low pressure. The coefficient of drag in the high-speed car decreased as the free stream increased. The value of the coefficient of drag (Cd) from this research was app. 0.567.

Aerodynamics analysis of the car using Solidworks flow simulation with rear spoiler using CFD

The Vehicle stability is the major concern in the high speed car being produced now a day. The fuel consumption is mainly affected by different forces which include the force due to drag and lift, force due to self-weight, side forces and also the thrust acting on the vehicle. About 60% of the drag is which is caused due to the relative motion between the air and the vehicle is created at the rear end. The fuel consumption can be increased by reducing the drag force at the rear end. So this paper aims to reduce the drag force which helps in improving the fuel consumption which leads to environment protection. We used a Sedan car with various types of spoilers for reducing the aerodynamic drag force. The design of the car was done on SOLIDWORKS and also it was used for the analysis in SOLIDWORKS FLOW SIMULATION. The analysis was done to find out the drag and lift forces at various velocities and by using different spoilers. This study proposed a numerical model which was effective when done on the computational fluid dynamics (CFD) so as to obtain the different flow structure around the car with spoiler at the rear end.

Vertical vibration analysis of a coupled vehicle-container model of a high-speed freight EMU

The high-speed freight trains are increasingly using containers for efficient cargo handling and improved transportation economy. The dynamic interactions of the containers with the vehicle can cause greater vehicle vibration, especially at speeds as high as 350 km/h. This study investigates the vibration response of a high-speed freight car (electric motor unit, EMU) through development and analysis of a coupled container-vehicle multibody dynamics (MBD) model in the SIMPACK platform. The flexible carbody is established in the ANSYS software. An integrated MBD model which ignore the viscoelastic coupling between the containers and the carbody and a MBD model of the vehicle without the containers are established as the reference models. The viscoelastic parameters study of the cargo mounting system and the vertical vibration responses of the carbody, containers and the bogies under different operating speeds and different container loads are analysed. The simulation results are discussed to provide design guidance for the containers’ mounts. The results suggested that the vertical vibration response of the coupled system is strongly affected by the viscoelastic properties of the mounting system. Stiffer container mounts revealed dominant vibration responses of the containers in the vicinity of the modal frequencies of the carbody.

Experimental Investigation of a Spoiler’s Impact on the Flow Pattern of a High-Speed Sport Car

The relative motion of a car causes air resistance. This generates an aerodynamic force in the opposite direction of motion...

Dynamic model of high speed following traffic flow

For the physical phenomenon of high-speed car following in the road traffic flow, all the vehicles with small spacing do not run at low speed. The speeds of the vehicles are significantly higher than those they normally should be when they are in this vehicles’s density. There are more than 7% of high-speed following vehicles in the measured data. At present, the traditional traffic flow model cannot simulate the phenomenon of high-speed car following, so a new nonlinear dynamic mathematical model is needed to describe and analyze the physical phenomenon. In order to study the physical phenomenon of high-speed car following in road traffic, a traffic flow dynamics model for simulating the phenomena is proposed, which combines with the prospect theory and takes into account some factors such as driver’s decision-making behavior and randomization. It is called HCCA (high-speed car following celluar automat) model. In the model, the prospect theory is used to analyze the driver’s lane changing behavior under the uncertain conditions. Combined with the characteristics of the radical driver, the dynamic prediction speed is considered for the front car followed by the radical driver, and the HCCA dynamics rules of high-speed following traffic flow mechanics are defined. By the computer numerical simulation, the evolution mechanism and the characteristics of high-speed car-following flow are studied. The results show that compared with the symmetric two-lane cellular automata (STCA) dynamic model, the HCCA dynamic model established in this paper can simulate abundant traffic physical phenomena, and reproduce complex traffic phenomena such as free flow, synchronous flow and wide-range motion congestion. Finally, the phenomenon of high-speed car following is simulated and the results of high-speed car following rate over 7% with small spacing are in good agreement with the measured results. It overcomes the shortage that traditional STCA model cannot simulate the synchronous flow. It is found that the larger the proportion of radical drivers, the larger the high-speed car following rate and traffic flow with small spacing are under the same road density. The high-speed car following traffic flow mechanics model proposed in this paper has a certain reference significance and practical value for analyzing the physical phenomenon of high-speed car following and enriching the traffic flow theory.

Dynamics simulation of a high-speed railway car operating in low-temperature environments with stochastic parameters

The dynamic performance of a high-speed railway vehicle operating in low-temperature environments was studied through simulations using a stochastic, parameter-based, dynamic model. This model considered the random distribution of the design and operational parameters due to variations in operating conditions and manufacturing errors, as well as the maintenance procedure. The effects of the ambient temperature on the properties of the vehicle suspensions, such as the rubber-made elements, hydraulic dampers and air springs, were determined through laboratory tests. The results suggest that the low-temperature operating conditions substantially increase the stiffness and damping properties of the rubber components and hydraulic dampers, especially when the temperature is less than −20°C. In extremely low-temperature operating conditions, the vehicle with a relatively small equivalent conicity could be subjected to car body hunting, thereby deteriorating the ride comfort. Therefore, a minimum wheel equivalent conicity of greater than 0.1 is suggested. By considering the scenarios of snow build-up on the bogie, the results further show that the snow could limit the motion of the suspension and significantly affect the dynamic performance of the vehicle. However, the effect of the added mass on the bogie is considered to be negligible.

Numerical analysis of an automatic deployment to enhance the downforce of the vehicle

ABSTRACT Aerodynamic force plays a major role in motorsport since it is independent of the forced system. The efficient aerodynamic car has the capability of consuming less energy and better vehicle handling. This paper is about how to enhance the downforce aerodynamics to achieve better handling of the vehicle even at corners. The vehicle undergoes deceleration at corners to get more grips on road. During cornering the vehicle loses its downforce due to the aerodynamic effects. To compensate that loss, the vehicle decelerates at the corners. Due to this deceleration, the energy is wasted and the velocity of the car decreases drastically. In order to compensate that the latest high speed cars and other cars use the tail wing and spoilers to achieve great downforce. However, the downforce created is not much enough to hold the vehicle in the track during cornering and mostly under braking issues leads to the delamination of tyres. Furthermore, the variable is added on the device at the bottom of chassis to increase the downforce of the vehicle.

Justification of the bridge span vertical stiffness on high-speed railways

When designing bridges on high-speed railways, special attention should be paid to ensuring the safety of train traffic and the comfort of passengers. Excessive structure deformations (both elastic and non-elastic) result in unfavorable irregularities in the train movement pattern on the bridge and so can lead to violation of the traffic safety requirements as well as to vibration and acceleration of the train body, which is inadmissible due to its effect on the human body or the transported goods. In this paper, based on numerical simulation, the results of the study of the motion of a high-speed train along bridge structures of the dynamic bridgetrain interaction was performed with respect to various models of high-speed trains running along the bridges. The obtained dependences help to provide a practical assessment of high-speed passenger car dynamics and passenger comfort under the most unfavorable conditions, when the train is running along a multi-span bridge. For these purposes, the dependences of the admissible value of the relative vertical deflection are presented, based on the envelope curves that show the typical dynamic passenger car parameters (natural frequency of car oscillations) and Corresponding with their oscillations on the multi-span girder bridges with various lengths

Multi-objective optimization of electric multiple unit wheel profile from wheel flange wear viewpoint

The CRH1 train is one of the main commuter trains in China which is mostly operating on typical and high-speed lines. Previously, a high-speed car wheel profile was used on the CRH1 train, but it does not match well with the train suspension parameters and also causes the instability of the train on tangent track and large curved track. Therefore, a new profile was designed as the replacement of the old one for the CRH1 train. However, the use of the new profile results in the serious wheel flange and rail gauge corner wear but it can provide better stability compared to the old profile. This paper first presents the evaluation of using the two profiles, and then a development of the wheel profile is objected in terms of both currently used profiles, which is not only to minimize the flange wear and also take the vehicle dynamic behavior into consideration. A multi-objective optimization method was, therefore, to propose for the minimization of the lateral force and the stability of wheelsets. The requirements of the wheel profile geometry are investigated through proposed optimization method. Finally, the profile satisfied the safety requirements of the vehicle has been provided by using the particle swarm optimization method. Furthermore, the evaluation of vehicle dynamic has been performed by using Multi-Body Simulation Software. The entire design process has been completed in a closed-loop procedure programed in MATLAB. The findings show that the developed profile after the optimization procedure is fairly acceptable for the requirements of the wheel-rail interface and dynamic behavior of CRH1 train.

Medico-Legal Implications of C1 Vertebral Fractures. Case Report

Abstract Introduction: The upper C1-C2 column is the subject of several erroneous diagnostics. The most common mechanisms of injuries include fall from high-impact skulls, car accidents, etc. Vertebra C1 can also be injured by mild trauma. The Japanese show that atlas fractures occur in about 2-13% of the cervical spine fractures and about 1.3% of the total spinal cord injuries. It is underlined that CT examination is the most useful diagnostic method. The Czechs show that the atlas lesions appear in 1-2% of the cervical spine lesions. Americans reported fracture of the atlas in 7% of the cervical spine fractures. Even if CT has shown its value, lateral radiography is recommended in C1-C2 fractures. When victims are children or people injured in high-speed car crashes, the reported mechanisms were the fall from a high level and the impact on the tip of the flexed skull. The Italians mention that the C1-C2 area is the most exposed diagnostic area with errors. Material and methods: given the difficulty of establishing a diagnosis of C1 type fractures, we present in this paper such a case. We highlight the value of a CT scan. The victim is a 26-year-old woman with a trauma from the wall. The main issue in this case is that the diagnosis made by the radiologist seems to be wrong, the electronic and imprinted copies are of inferior quality. A second opinion revealed a very fine fracture that seemed to come from an older date than the date when the victim claimed she was assaulted. The better the lesions, the more misleading the interpretations. Any imaginary imaging lesion, especially if it is obvious in electronic reconstructions, must be brought to the attention of the physician if they are taken into account by "image". The axial CT sections may omit some lesions under certain conditions, for example at the upper and lower poles of a spherical, ovoid or cubic structure, such as the atlas lateral mass. Conclusions: the diagnostic solution in this case is the reconstruction of the axial sections in several planes. The crack can be highlighted, in the case of a reconstructed image, only after stacking the axial images. The mechanism could be through sudden compression, during a sudden head movement, uninitiated and uncontrolled by the neck muscles, when a movement occurs over the degree of elasticity of the occiput-atlas joint, the occipital condyles compressing abruptly, unilaterally one of the atlas masses. In such clinical cases, we experience pain, muscle contraction and torticollis, on a normal neurological background.