International Journal of Vehicle Safety (8 papers in press)
Research status of electronic differential control of electric vehicle driven by in-wheel motor
by Di Tan, Guangcheng Ge, Liwei Shi, Kun Yang
Abstract: The electric vehicle driven by the in-wheel motor has the advantages of simple structure, high efficiency and easy control, and it has broad development prospects. Electronic differential control based on the structure of the electric vehicle chassis driven by the in-wheel motor can improve the power performance, manoeuvrability and safety of the vehicle. However, this technology also has some technical difficulties. How to overcome these difficulties is significant in this technology. This paper analyses the electronic differential control technology of an electric vehicle driven by an in-wheel motor in various automobile companies and universities, and summarises the current control strategies in related fields at home and abroad.
Keywords: in-wheel motor; electric vehicle; electronic differential technology; control strategy.
Application of weighted allocation method of multi-index sample sizes in traffic accident investigation
by Junfeng Wang, Jiqing Chen, Fengchong Lan, Qingshan Liu, Lingyun Xiao
Abstract: In the in-depth investigation of traffic accident sampling, different grades of roads are stratified, and stratified sampling methods are used for sample survey. In stratified sampling, when the allocation of sample size needs to consider multiple indices, the traditional method treats each index equally, or uses the variance of the indices to evaluate the weights. This ignores the subjective preference of the investigator. In addition, there may be some cases where the variance difference of some important indices is small or missing, resulting in the sample size allocation failing to achieve the desired goal. In view of this situation, this paper adopts a compromise scheme, considering the weight of each index, the weighted average method is used to allocate the sample size. In order to evaluate the weight of each index, the analytic hierarchy process (AHP) coefficient of variation (CV) method is used in this paper. According to the loss value of corresponding indices of different grades of roads, the weight of different indices is evaluated comprehensively from subjective and objective aspects. Then, according to the proportional allocation method, the samples of each index of each layer are determined. Finally, the sample size of each layer is distributed by weighted average method to maximise sampling accuracy.
Keywords: traffic accident investigation; stratified sampling; distribution method; weight; analytic hierarchy process; coefficient of variation method.
Numerical reconstruction for a multi-car collision dynamics
by Shen Rui Hong, Lan Fengchong, Xiao Lingyun, Chen Jiqing
Abstract: In order to accurately determine the collision relationship of each vehicle in complex traffic accidents, combined with the scene trace and accident simulation, an accident reconstruction method is proposed. The method examines the accident scene and the accident vehicle, which can forecast the accident process in advance and determine the approximate vehicle collision speed by the dynamics method. Then, based on the pre-determination, the PC-Crash software is used for accident reconstruction to more accurately determine the accident scenario and the vehicle collision parameters. The above method was used in a four-car serial collision on a rainy highway. The collision information of the accident cars was read using Bosch's data reading tool CDR (Crash Data Retrieval). The results showed that the method can accurately reconstruct complex traffic accidents and provide an effective solution for determining the collision relationship of vehicles and the responsibility of traffic accidents.
Keywords: trace identification; complex traffic accident; accident reconstruction; PC-Crash; crash data retrieval.
Analysis of lower limb injury mechanism of an average Chinese pedestrian lower limb FE model in lateral impact
by Jiqing Chen, Renjie Cheng, Fengchong Lan, Yunjiao Zhou
Abstract: According to the statistics, lower limb injuries are the second most frequent region of traffic injuries. For the in-depth study of the biomechanical response and injury mechanism of pedestrian lower limb, the pedestrian lower limb biomechanical finite element (FE) model with high biological fidelity was developed and verified. By applying the proposed model, simulation studies were conducted to investigate pedestrian lower limb dynamic responses and injuries under different bumper foam filling structures and bumper collision heights during lateral impact. Simulation results demonstrated that filling the cushion foam between the bumper cover and the anti-collision beam can effectively reduce the injury index of pedestrian's lower limbs, and the trapezoidal foam structure has better protection effect. In addition, appropriately lowering the bumper collision height can improve the car's friendliness to pedestrians lower limbs.
Keywords: biomechanics; pedestrian lower limb; finite element model; lateral impact; injury; simulation.
Modelling aspects and risk analysis for road vehicles under non-stationary wind excitation
by Xiaoyu Zhang, Carsten Proppe
Abstract: Strong crosswind has a great influence on the stability of road vehicles. At exposed locations (e.g. embankments, long bridges), the topographical features may magnify the wind effects and thus cause accidents. In order to evaluate the accident risk of road vehicles in a more realistic way, the model for the wind-vehicle system has to take the non-stationary characteristics of natural wind into account, and specific vehicle models for different vehicle types have to be developed. This paper details a mathematical model and physical scenario of road vehicles running under strong crosswinds. Possible road vehicle accidents due to excessive sideslip, yaw rotation and overturning are taken into account. In order to quantify the accident risk under strong crosswind, failure probabilities for different types of road vehicle are computed and analysed.
Keywords: risk assessment; non-stationary wind; vehicle dynamics.
Head injury of CHARM-70 FE model and a comparative study with Hybrid III and GHBMC model
by Hequan Wu, Xiaoyan Qian, Qifan Ren, Xuehui Zhan
Abstract: In the paper, the Hybrid III FE head model is first validated through dummy impact experiments. Then, the CHARM-70 head model was developed, and the structure, head injury and dynamic mechanical response of the model are studied. Subsequently, the GHBMC head model is introduced to compare the dynamic mechanical response of the forehead to the steering wheel edge under the same speed with the Hybrid III and the CHARM-70. The result demonstrates that the CHARM-70 model has high biological fidelity. Meanwhile, owing to different material properties, the GHBMC model shows the best stiffness and force response, followed by the CHARM-70 model, and
finally the Hybrid III model. Finally, the different settings of material parameters indicate a fine response to the decline rule of bone strength caused by human age, which is meaningful for the development of different age, body and other special population models in the future.
Keywords: CHARM-70; Hybrid III; GHBMC; injury mechanism; biological fidelity; material parameters.
Road sign detection using edited shuffled frog leaping algorithm
by Ameur Zaibi, Anis Ladgham, Anis Sakly
Abstract: This paper suggests a new system for the automated detection of road signs. This driver assistance system detects traffic signs that have a red border with different shapes (circular, triangular, hexagonal). So, our approach relies on Support Vector Machines (SVM) implementation for road signs detection supported by feature extraction technique supported employment of a range of filters from Gabor that simplifies the recognition of points of interest in our database. On the other hand, our approach has improved the edited shuffled frog leaping algorithm (ESFLA) optimisation technique that helps in road signs detection, and this technique is termed GABOR-ESFLA-SVM. This strategy ensures an intelligent recognition system. The obtained results show that this optimised classification provides better results compared with the previous dual classification GABOR-SVM and other published research works.
Keywords: road signs with red border detection; ESFLA optimisation; optimal solution; Gabor wavelets; features extraction; Gabor representation; SVM classification; fitness function.
Evaluation of behaviour of an obese human body model in frontal sled tests
by Hamed Joodaki, Bronislaw Gepner, Maika Katagiri, Jason Kerrigan
Abstract: 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 response 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 systems for front-seat occupants with obesity.
Keywords: obese HBM; obesity; motor vehicle collisions; biofidelity; GHBMC.