To enhance the trajectory tracking accuracy and manoeuvring stability performance of semi-trailer trains, a Third-order Multi-point Preview (TMP) drive model is designed, based on the Sliding Mode Control (SMC) theory. Firstly, a linear three-Degree-of-Freedom (3-DOF) model of a three-axis semi-trailer train was built, and the validity of which is verified. Lateral deviation of the vehicle preview point is used to determine the optimal rate of change of the optimal lateral acceleration. Then, the SMC drive controller is designed based on the consideration of the semi-trailer train yaw rate and articulated angle. Finally, the TMP-SMC driver model has been simulated and tested in a Double Line Change (DLC) condition, using a combined simulation of MATLAB/Simulink and TruckSim. The designed TMP-SMC driver model significantly enhances the trajectory following accuracy at low speeds and the manoeuvring stability at high speeds of semi-trailer trains, and reduces the driver's steering effort.
In order to solve the problem that the measured values of key state parameters such as the lateral velocity and yaw rate of the vehicle are easily interfered by random errors, a filter estimation method of vehicle state is proposed based on the principle of robust filtering and the unscented particle filter algorithm. Based on the establishment of a 3-DOF non-linear dynamic model and the Dugoff tire model of the vehicle, the adaptive robust unscented particle filter(ARUPF) is used to filter and estimate the parameters of the vehicle state, and to realize the longitudinal and lateral speed as well as the yaw rate of the vehicle during the driving process. The simulation and the real vehicle test results show that based on the adaptive robust unscented particle filter algorithm, the vehicle driving state estimation can be realized, the measurement parameters can be effectively filtered, and the estimation accuracy is high.
The correlation between vehicle front profiles and multiple head injury forms in accidents remains unclear. Three hundred simulations were conducted by considering five vehicle front-end variables: bumper centre height, Bonnet Length (BL), Bonnet Leading Edge Height (BLEH), Bonnet Angle (BA) and Windscreen Angle (WA). HIC15, angular acceleration, maximum principal strain and cumulative strain damage measure were calculated to evaluate Skull Fracture (SF), Sub-Dural Hematoma (SDH) and Diffuse Axonal Injury (DAI). Prediction models were developed and evaluated by using back-propagation neural network algorithms. Results reveal that BLEH exhibits the highest overall significance of 0.41, which was the most sensitive parameter affecting all three injury forms. SF was significantly correlated with BL, with an importance value of 0.12. Changing WA and BA demonstrates significant effects on SDH and DAI, with significance values of 0.29 and 0.33, respectively. The results can give a comprehensive reference for the design and optimisation of vehicle front profiles.
Estimating the real-time state of a vehicle is critical for driver assistance systems. In this study, we propose a framework that utilises deep learning (DL) and monocular cameras to obtain information about vehicles. We first estimate the velocity of the ego vehicle using optical flow. Then, the position of the visible vehicle is tracked and predicted using deepSORT and projection geometry. Finally, an extended Kalman filter (EKF) is used to combine the velocity, tracking information and relative position to estimate the trajectory of both vehicles in a common coordinate frame. We evaluated the accuracy of the visible vehicle's position using three public data sets. The results show that our proposed algorithm has a consistent Root Mean Square Error (RMSE) between 5.12 and 6.272. On two of the data sets, our algorithm outperforms other data-driven supervised DDSDL algorithms. To evaluate trajectory generation, we conducted both simulated experiments and real-world tests, demonstrating that our algorithm generates accurate vehicle trajectories.
To improve the aerodynamic characteristics of the rear wing and enhance the handling stability of the racing car, based on the orthogonal experimental design and iSIGHT platform, the multi-objective optimisation of the structural parameters of the spatial layout of the rear wing was carried out to determine the optimal combination of the angle of attack between the rear wings and the clearance between adjacent wings. A hybrid fuzzy PID variable rear wing control system was developed to suppress vehicle roll by real-time control of the flap angle of attack. The co-simulation results show that as the road adhesion coefficient decreases, the variable rear wing system improves the handling stability of the car more and more and the suppression of vehicle roll gradually increases, with the improved handling stability on slippery roads, the car's cornering performance and driving safety are enhanced.
An earlier study by authors implemented Corpuscular Particle Method (CPM) for simulations of Pedestrian Protection Airbags (PPA). Present study utilised the CPM to investigate the effect of gas flow on the airbag's unfolding procedure. A PPA was designed to cover bottom of windshield and A-pillars where pedestrian head is more likely to hit and stiffness is high. This paper aims to investigate the effect of six folding patterns on PPA deployment behaviour and pedestrian head injuries. For each folding pattern, headform impact on nine points was simulated. Head acceleration curves, HIC values, PPA pressure and friction curves were exported. Results show that a PPA can reduce pedestrian head injuries by up to 90%. Across six patterns studied in this research, the folding-rolling as the best pattern generates lowest HIC values and the rolling-folding and rolling-stochastic as the weakest patterns generate high HIC values as they have higher friction.
Since pedestrians are Vulnerable Road Users (VRU), the collision proportion and casualty rate are still high between vehicle and pedestrian, while the current Autonomous Emergency Braking (AEB) system lacks relative overall pedestrian test scenarios. Based on the National Automobile Accident In-depth Investigation System (NAIS) in-depth accident data about the collision accidents between passenger car and pedestrian in 220 cases, five typical AEB pedestrian system scenarios are obtained by clustering analysis and chi-square test in this paper; then, based on the second typical scenario, three more severe test scenarios are obtained by analysing pedestrian-vehicle collision avoidance model and the actual road traffic situation in China from the perspective of user acceptance; finally, eight times field operation test shows that the test vehicle is subject to premature braking. This paper provides a reference for establishment and further optimisation of AEB pedestrian test scenario in China.
We investigated the impact of vehicle-related factors on speed at which accidents occur and accident severity rates. To achieve the objectives of the study, incident rate ratio effects were considered. The data was collected from the Ghana Police Motor Transport and Traffic Department accident database, vehicle owners, garages of auto-mechanics and welders in Ghana. The result shows that engine capacity, vehicle type and type of drive had significant impact on rates of accident severity. Additionally, the effect of engine capacity, vehicle age, vehicle type and type of drive on the speed at which accidents occur was also highly significant. An increase in speed and accident severity rates was explained primarily by high-engine capacity, 4WDs, AWDs and the size of vehicles. Again, an increase in vehicle age increased injuries. Therefore, it is important for authorities to strengthen the enforcement of traffic rules to control drivers' aggression speed and reduce accidents.
Today, the use of mobile phones has become a concern due to the advancement of technology. The aim of this study is to investigate the status of mobile phone addiction in drivers of Khuzestan province. The statistical population of the study was 120 drivers who had the experience of accidents and 120 drivers who had no accidents were selected by simple random sampling. In this study, the standard mobile phone addiction questionnaire was used. The results showed that there is a significant difference between the rate of mobile phone addiction of injured and non-injured drivers (P <0.01). There is a significant difference in the rate of mobile phone addiction of accident and non-accident drivers based on the duration of mobile phone use, marital status and their driving history (P <0.05). According to the results, the relationship between cell phone addiction and the occurrence of traffic accidents is obvious.
In this paper, the biodynamic responses exposed to human seated posture were investigated by developing a biodynamic model based on anthropometric data for various Indian male subjects. Four degrees of freedom model for the human seating posture was constructed to extract the different biodynamic responses at several low-frequency vibrations. The male subjects were categorised by age and body weight. A total of nine different categories were identified for the examination. The impact of body mass, age, stiffness, and damping coefficient of the body segments was analysed using MATLAB-based code. The biodynamic responses of seated posture have been measured in terms of seat-to-head transmissibility (STHT), driving point impedance (DPMI), and apparent mass (AM). The present work will help to predict the biodynamic responses of the seated human body under various vertical excitations. The results of the current work show that the proposed approach was very much effective and reliable for designing a seated posture ergonomically.
Lasers combined with GNSS can be used to create a safer design of automobiles. Laser sensors can detect if an accident has taken place. Combination of both the data can be used to inform fire brigade, ambulance, friends and family in case of accident. This technology can save lives and avoidable injuries. It can be new dimension in automobile safety and is comparable to airbags or seatbelts. Multiple GNSS were used in parallel for more accuracy, network coverage and reliability. Combination of satellite phones and sim card was used to ensure that the message reaches even in the presence of network, software and hardware failures. Multiple sensors such as gyroscope, accelerometer and proximity sensor were used to increase the accuracy of observations. A vehicle can become debris and disintegrate. A vehicle can fall into an underground pit and reach a place where no network connectivity is available.
Road conditions at interchanges are more complicated than those on basic freeway segments, which results in high probability of risky situations. To simulate the driving safety of an articulated vehicle on a typical interchange, a virtual vehicle model is developed and validated. Driving simulations are conducted on each ramp of the interchange. Influences of longitudinal velocity and road friction are discussed. The results show that the lateral accelerations increase with increased driving speed or decreased curve radius. The articulated vehicle body rolls to the inside of the circular curves and transition curves, and the roll angles increase with the decrease in speed. The low-speed heavy vehicle might roll over to the inside of the large banked curves. The allowed driving speeds are decreased and the critical speeds for sideslip are obtained at low friction conditions. Accident prevention methods are suggested to enhance the driving safety on the interchange.
The goal of this study was to assess the behaviour of an obese Human Body Model (HBM) in frontal sled tests. The results of rear-seat sled tests with an obese (BMI = 35) Post Mortem Human Surrogate (PMHS) were used to evaluate the performance of the obese HBM in matching conditions. Also, the responses of a non-obese HBM (BMI = 25) and the obese HBM were compared in a front-seat frontal impact test. In the rear-seat tests, both the obese HBM and the obese PMHS experienced a large forward excursion, delayed lap belt engagement with the pelvis, and a reclined-to-upright torso angle throughout the tests, which were the effects of large body mass and thick flesh. In the front-seat simulations, the obese HBM experienced a larger excursion than the non-obese HBM. The obese HBM can be a useful tool to design and optimise restraint system for front-seat occupants with obesity.
For studying the pelvic injury mechanism and the difference among different age groups in the car crash, elderly pelvic model was developed and validated in this paper. The elderly pelvis model was compared with the young people's pelvis model and the children's pelvis model. The results show that the physiological and geometric size of pelvic model of elderly is similar to that of young people, but both of them are quite different from the children's. Compared with the other two models, the elderly pelvic model has the strongest response of peak force and Dforce (deflection at maximum force), but the weakest response of maximum deflection under different impact velocities from 4 m/s to 15 m/s. The peak force and Dmax increased exponentially and linearly with the impact energy in all three models, respectively. The most vulnerable parts of the injury were the ischio-pubic rami, iliac-sacral junction and acetabulum area.
Bumper is a structure attached to the vehicle at both front and rear end to dissipate the kinetic energy generated by an impact and protect the vehicle components and its occupants. An ideal bumper energy absorbing system should be crash-worthy at both low-speed and high-speed collisions as well as meet the requirement of pedestrian safety. Energy absorbers are used between the bumper fascia and bumper beam to improve crashworthiness. Key areas of research focused to optimise the bumper energy absorbing systems are the selection of material and the structural design/geometry. Different materials and structural designs are being tried out to optimise the bumper energy absorbing system to meet the requirements. The characteristics, advantages and disadvantages of these materials and structures are reviewed in this paper.
Carbon Fibre-Reinforced Materials (CFRM) are used in automotive, aerospace, building material and other fields. In application of CFRMs, various damage initiation criteria and evolution laws have been continuously proposed. In this study, Hashin's, Chang's and Linde's damage initiation criteria, and linear and exponential damage evolution laws were studied and the performances of their different combinations on simulating damage of CFRM were compared under the Open-Hole Tension (OHT), Open-Hole Compression (OHC) and low-speed impact conditions. Results showed good performance was made by (1) Hashin's damage initiation criterion + the exponential damage evolution law; (2) Linde's damage initiation criterion + the linear damage evolution law and (3) Chang's damage initiation criterion + the exponential damage evolution law. Using a Gross Correlation Index (GCI) to evaluate the overall performance of the six combinations, Chang's damage initiation criterion + the exponential damage evolution law ranks the best, revealing their wider applicability.
In order to simulate the injury of rear children occupants in the frontal impact, a previously validated six-year-old child Finite Element (FE) model was used to load ECE R44 testing conditions. Through the resultant head acceleration, pressure, brain tissue Von Mises stress, brain tissue shear stress, shear force and axial force of neck, compression of chest and abdomen to compare the protective effects of the six-year-old rear seat occupant on forward-facing child seat restraint system and booster in different collision speeds. The results indicate that: when the collision speed is low, there is little difference of the child FE model's injury criteria in the two restraint systems, while the protective effect of child seat restraint system to the children is better than booster with the increase of the collision speed.
