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Parameter Optimization of Anti-roll Bar Based on Stiffness

Wuhan University of Technology-Zhenyu Wang, Donghua Guo, Haoyu Wang, Yifeng Jiang, Ming Li, Xiaoge Hou
Suizhou-WUT Industry Research Institute-Gangfeng Tan
  • Technical Paper
  • 2020-01-0921
To be published on 2020-04-14 by SAE International in United States
Anti-rolling bar is an important structural part of the automobile, which can effectively prevent the automobile from rolling and improve the safety of the vehicle during bending. In the design of the current anti-rolling bar, the stiffness of anti-rolling is determined based on experience or oversimplified mathematic model. In this paper, an anti-rolling bar is determined by 7 parameters, and forces in different directions and perpendicular to the bar are applied at both ends. The mathematical model of stiffness of anti-rolling bar is established by combining the Deformation Energy Theorem and Castigliano Theorem. Nonlinear programming and genetic algorithm are used to acquire the optimal solution and corresponding values of parameters of the mathematical model. Then, by means of partial least-squares regression method, the correlation of different parameters to the stiffness of anti-rolling bar is analyzed. Besides, the stiffness of the anti-rolling bar is calculated by finite element method. On the experimental bench, the tensile and compressive tests were carried out on the equal-scale shrinking model of the bar, which verified the correctness of the influence…
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An Image Recognition Application Method for Vertical Movement of Vehicles

Wuhan University of Technology-Ming Li, Gangfeng Tan, Zhenyu Wang, Haoyu Wang, Yifeng Jiang, Donghua Guo, Jiaming Feng
  • Technical Paper
  • 2020-01-0733
To be published on 2020-04-14 by SAE International in United States
In ITS, image processing technology is applied to a wide variety of areas such as visual-based intelligent vehicle navigation, visual-based traffic monitoring and visual-based traffic management. In the identification system of the vehicle body characteristics, most of the recognition is the license plate and the car emblem, etc. This paper proposes an image recognition application method for the vertical motion of the car while driving, mainly including vertical height detection and vertical displacement velocity acceleration recognition. The edge detection model of the image object is established by using the gray image to obtain the car motion segmentation image. At the same time, an image length and actual length coordinate conversion model is established, which can calculate an arbitrary actual length of the image object. In this paper, the Yuejin Shangjun X500 van is selected as the test vehicle. Using camera capture the video data and the height of the vehicle is recognized for each frame. The height is compared with the actual length. The absolute error can be controlled within 40mm, and the minimum relative…
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Decision Making and Trajectory Planning of Intelligent Vehicle’ s Lane-Changing Behavior on Highways under Multi-Objective Constrains

Wuhan University of Technology-Linzhen Nie, Zhishuai Yin, Haoran Huang
  • Technical Paper
  • 2020-01-0124
To be published on 2020-04-14 by SAE International in United States
Discretionary lane changing is commonly seen in highway driving. Intelligent vehicles are expected to change lanes discretionarily for better driving experience and higher traffic efficiency. This study proposed to optimize the decision-making and trajectory-planning process so that intelligent vehicles made lane changes not only with driving safety taken into account, but also with the goal to improve driving comfort as well as to meet the driver’ s expectation. The mechanism of how various factors contribute to the driver’s intention to change lanes was studied by carrying out a series of driving simulation experiments, and a Lane-Changing Intention Generation (LCIG) model based on Bi-directional Long Short-Term Memory (Bi-LSTM) was proposed. The inputs of the Bi-LSTM were data fragments of several influencing factors including the relative velocity and the distance between the relative vehicles, the type of the preceding vehicles, and the average velocity of the adjacent traffic flows, that over a certain period of time, which was determined via examining subjects’ visual behaviors of the left view mirror or the right view mirror. By combining the…
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Driver Distraction Detection with a Two-stream Convolutional Neural Network

Wuhan University of Technology-Yuefeng Ma, Zhishuai Yin, Linzhen Nie
  • Technical Paper
  • 2020-01-1039
To be published on 2020-04-14 by SAE International in United States
Driver distraction detection is crucial to driving safety when autonomous vehicles are co-piloted. Recognizing drivers’ behaviors that are highly related with distraction from real-time video stream is widely acknowledged as an effective approach mainly due to its non-intrusiveness. In recently years, deep learning neural networks have been adopted to by-pass the procedure of designing features artificially, which used to be the major downside of computer-vision based approaches. However, the detection accuracy and generalization ability is still not satisfying since most deep learning models extracts only spatial information contained in images. This research develops a driver distraction model based on a two-stream, spatial and temporal, convolutional neural network (CNN). The CNN in both stream is improved with Batch Normalization-Inception (BN-Inception) modules which increase the sparsity in the inception modules in GoogLeNet, so that the network is further speeded up and also more adapted to features at various-scales. The original RGB image is fed into the spatial stream CNN to extract static information, and the feature map of optical flow field extracted from adjacent image frames is…
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A Pre-warning Method for Cornering Speed of Concrete Mixer Truck

Wuhan University of Technology-Yifeng Jiang, Haoyu Wang, Zelong Wang, Zhenyu Wang, Ming Li
Suizhou-WUT Industry Research Institute-Gangfeng Tan
  • Technical Paper
  • 2020-01-1003
To be published on 2020-04-14 by SAE International in United States
The high gravity center of the concrete mixer truck reduces the truck’s stability while steering, and the rolling stirring tank makes the stability even worse than the regular engineering vehicle due to the dynamic variation of centroid position. Most of the researches on the rollover stability of concrete mixer trucks focus on the rollover model establishment and dynamics simulation module. The influence of concrete centroid changes is ignored when the safe cornering speed is calculated. This paper proposes a pre-warning method for cornering speed of concrete mixer truck based on centroid dynamic simulation. In the method, the mixing tank stirring model and the vehicle driving dynamics model are established on the Fluent and TruckSim simulation platforms, respectively.The theoretical speed threshold obtained by simulation is used as the evaluation index of warning of the speed for steering. First, the dynamic simulation of the stirring tank model is carried out by Fluent. According to Newton Leibniz numerical calculation method, Matlab is used to obtain the mathematical model of the centroid position and the main parameters of the…
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Kalman Filter Slope Measurement Method Based on Improved Genetic Algorithm- Back Propagation

Wuhan University of Technology-Haoyu Wang, Donghua Guo, Gangfeng Tan, Zhenyu Wang, Ming Li, Yifeng Jiang, Meng Ye, Kailang Chen
  • Technical Paper
  • 2020-01-0897
To be published on 2020-04-14 by SAE International in United States
How to improve the measurement accuracy of road grade is the key content of the research on the speed warning of commercial vehicles in mountainous roads. If there is a large measurement error, the obtained speed threshold will be biased, posing a safety hazard. Conventional measuring instruments such as accelerometers and gyroscopes generally have noise fluctuation interference or time accumulation error, resulting in large measurement errors. In response to this situation, the Kalman filter method is often used for filtering to reduce the interference of unwanted signals, thereby improving the accuracy of the slope measurement. However, the Kalman filtering method is limited by the estimation error of various parameters, and the filtering effect is difficult to meet the project research requirements. In this paper, the acceleration of vehicle gravity, running speed and acceleration of parallel slope are used as auxiliary measurement parameters to improve the measurement method of mountain road slope. Based on the Kalman model, genetic algorithm (GA) and BP neural network are used to carry out the innovation , covariance matrix and the…
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Effect of stator surface area on braking torque and wall heat dissipation of magnetorheological fluid retarder

Wuhan University of Technology-ZhiQiang Liu, Zhongpeng Tian, Mi Zhou, Philip Agyeman, Justice Frimpong
Suizhou-WUT Industry Research Institute-Gangfeng Tan
  • Technical Paper
  • 2020-01-0937
To be published on 2020-04-14 by SAE International in United States
Magnetorheological fluid (MRF) is used as the transmission medium of the hydraulic retarder. The rheological properties are regulated by changing the magnetic field to realize the accurate control of the slow braking torque magnetic field. In magnetorheological fluid retarder and under the action of magnetic field, the flow structure and performance will be changed in a short time. The apparent viscosity coefficient increases by several orders of magnitude, the fluidity deteriorates and the heat generated by the brake cannot be well transferred through the liquid circulation. And it has influence on brake torque and wall heat dissipation of retarder to change stator surface area. In this study, the relationship between the braking torque of the MRF retarder and the stator surface area of the retarder was analyzed. In addition, phase change materials were used to directly dissipate heat on the retarder surface to reduce the retarder's operating temperature and improve the stability of the retarder's braking torque. In order to study the effect of stator diameter on braking torque of MR retarder under external magnetic…
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Research on Measurement Method of Aerodynamic Noise of Reactive Muffler

Wuhan University of Technology-Liping Xie, Zhien Liu, Zhu Yawei, Kai Liu, Chenhui Ye
  • Technical Paper
  • 2020-01-0423
To be published on 2020-04-14 by SAE International in United States
The aerodynamic noise of the reactive muffler is generated inside the muffler and mixed with the noise of the muffler body, which is difficult to be measured in the exhaust system. Based on two-microphone transfer function method and transmission loss of mufflers in the absence of airflow, this paper proposes a method for measuring the aerodynamic noise of the muffler. On the built-in muffler aerodynamic noise test bench, a special sampling tube was designed to measure the aerodynamic noise of the muffler at different flow velocity. For the sound absorption end with large reflection coefficient, the test and simulation data have large error at low frequency, and a correction formula that can eliminate the reflection of sound waves at the end of the test pipeline and form multiple reflections in the upstream and downstream is derived. The test results of the muffler on the test bench show: The aerodynamic noise data obtained by the sampling pipe is basically consistent with the simulation results by means of leading out measurement, which realizes the measurement of high…
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Research on the Best Driving Speed of the Deceleration Bump

Wuhan University of Technology-Ming Li, Haoyu Wang, Yifeng Jiang, Zhenyu Wang, Kailang Chen, Hanyu Zhang
Suizhou-WUT Industry Research Institute-Gangfeng Tan
  • Technical Paper
  • 2020-01-1088
To be published on 2020-04-14 by SAE International in United States
The ride performance and stability of the vehicle will decrease while the vehicle passing a deceleration bump with relatively high speed. If the speed is too low, the road efficiency and ride comfort will be affected. It is essential to identify the proper speed taking into account all the factors. In this paper, the dynamic model of the vehicle passing through the deceleration bump is established. Three kinds of indicators vibration weighted acceleration RMS, maximum vertical vibration acceleration and wheel load impact coefficient, are used to comprehensively evaluate the ride comfort and safety. The highway model, vehicle model, and common trapezoidal cross-sections bump models are set up in Carsim. Parameters such as vertical acceleration and tire force at different vehicle speeds are obtained. Then use the spline interpolation method to fit the data, and comprehensively consider the three indicators to get the best speed. Finally, the Audi A6 is used as the C-class test vehicle, and a section of the deceleration bump pavement is selected for the real vehicle test, and the simulation results are…
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Vehicle accelerator and brake pedal on-off state judgment by using speed recognition

Wuhan University of Technology-Zhongpeng Tian, Bo Yang, Cong linpeng, Fangyu Zhou
Suizhou-WUT Industry Research Institute-Gangfeng Tan
  • Technical Paper
  • 2020-01-1377
To be published on 2020-04-14 by SAE International in United States
The development of intelligent transportation improves road efficiency, reduces automobile energy consumption and improves driving safety. The core of intelligent transportation is the two-way information interaction between vehicles and road environment. At present, mainly the road environment information transmits to vehicles, while the information of vehicles rarely transmits to the outside. The electronic throttle and electronic braking systems of some vehicles using sensors to get the state of the accelerator and brake pedal, which can be transmitted to the outside through technologies such as the Internet of vehicles. But, Internet of vehicles technology has not been widely used, and it relies on signal sources, which is a passive way of information acquisition. In this paper, an active identification method is proposed to get vehicle pedal on-off state also driver operation behavior through existing traffic facilities. The research object is commercial vehicles driving on expressways. Vehicle speed is acquired by the camera, and specific vehicle models are identified by the camera to get the relevant vehicle parameters from vehicle model database. Combined with road environment data,…