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Technical Paper

A Non-Contact Overload Identification Method Based on Vehicle Dynamics

2019-04-02
2019-01-0490
The vehicle overload seriously jeopardizes traffic safety and affects traffic efficiency. At present, the static weighing station and weigh-in-motion station are both relatively fixed, so the detection efficiency is not high and the traffic efficiency is affected; the on-board dynamic weighing equipment is difficult to be popularized because of the problem of being deliberately damaged or not accepted by the purchaser. This paper proposes an efficient, accurate, non-contact vehicle overload identification method which can keep the road unimpeded. The method can detect the vehicle overload by the relative distance (as the characteristic distance) between the dynamic vehicle's marking line and the road surface. First, the dynamics model of the vehicle suspension is set up. Then, the dynamic characteristic distance of the traffic vehicle is detected from the image acquired by the calibrated camera based on computer vision and image recognition technology.
Technical Paper

A Pre-warning Method for Cornering Speed of Concrete Mixer Truck

2020-04-14
2020-01-1003
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.
Technical Paper

An Image Recognition Application Method for Vertical Movement of Vehicles

2020-04-14
2020-01-0733
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.
Technical Paper

Battery Thermal Management System Using Water as a Phase Change Material

2017-10-08
2017-01-2454
In these years, the advantages of using phase change material (PCM) in the thermal management of electric power battery has been wide spread. Because of the thermal conductivity of most phase change material (eg.wax) is low, many researchers choose to add high conductivity materials (such as black lead). However, the solid-liquid change material has large mass, poor flow-ability and corrosively. Therefore, it still stays on experiential stage. In this paper, the Thermal characteristics of power battery firstly be invested and the requirements of thermal management system also be discussed. Then a new PCM thermal management has been designed which uses pure water as liquid phase change material, adopts PCM with a reflux device for thermal management.
Technical Paper

Brake Guidance System for Commercial Vehicles with Coordinated Friction and Engine Brakes

2017-09-17
2017-01-2508
Using friction brakes for long time can increase easily its temperature and lower vehicle brake performance in the downhill process. The drivers' hysteretic perception to future driving condition could mislead them to stop untimely the engine brake, and some other auxiliary braking devices are designed to increase the brake power for reduction of the friction brake torque. The decompression engine brake has complex structure and high cost, and the application of eddy current retarder or hydraulic retarder on the commercial vehicles is mainly limited to their cost and mass. In this paper, an innovative brake guidance system for commercial vehicles with coordinated friction brakes and engine brake is introduced to guide the drivers to minimize the use of the friction brakes on the downhill with consideration of future driving conditions, which is aimed at releasing the engine brake potential fully and controlling the friction brake temperature in safe range.
Technical Paper

Co-simulation Based Hydraulic Retarder Braking Control System

2009-10-06
2009-01-2907
Hydraulic retarder has been widely applied on military vehicles and heavy commercial vehicles because of it could provide great brake torque and has lasting working time [1]. In order to reduce driver's frequent actions in braking process and prevent hydraulic retarder system from overheating, it is need to apply constant braking torque control, this control target has a strict requirement to hydraulic control system design. Many parameters often require repeated test to determine, which increases the R&D cost and extends the research cycle. This paper tries to find a time-efficient research method of hydraulic retarder control system through studying on a heavy military vehicle hydraulic retarder system. Hydraulic retarder model is set up through test data. The hydraulic control system is built based on AMESim. Controller model is set up based on PID control. The whole vehicle brake model is built based on MATLAB/Simulink.
Technical Paper

Combined Hill Descent Braking Strategy for Heavy Truck in the Featured-Slope

2017-09-17
2017-01-2535
The continuous braking for the brake drum will cause the brake thermal decay when the heavy truck is driving down the long slope in the mountain areas. It reduces the heavy truck’s braking performance and the braking safety. The engine braking and the hydraulic retarder braking both consume the kinetic energy of the heavy truck and can assist the truck driving in the mountain areas. This research proposes a combined hill descent braking strategy for heavy truck based on the recorded information of the slopes to ensure the braking safety of the heavy truck. The vehicle dynamic model and the brake drum temperature rising model are established to analyze the drum’s temperature variation during the downhill progress of the heavy truck. Then based on the slope information, the combined braking temperature variation is analyzed considering the characteristics of the engine braking, the drum braking and the hydraulic retarder braking.
Technical Paper

Design and Simulation Analysis for an Integrated Energy-Recuperation Retarder

2016-04-05
2016-01-0458
Vehicle auxiliary braking system is very significant to the brake safety. The eddy current retarder (ECR) has a good braking performance, but the braking torque would fade under high speed domain. In the contrary, the regenerative brake (RGB) could provide a satisfied braking performance in high speed domain. However, the braking torque in low speed domain is insufficient. This paper proposed a novel concept of the integrated energy-recuperation retarder (IEER), which would take advantage of the merits of both the ECR and the RGB to have a steady braking performance in all-speed domain. The IEER integrates the structures of rotary eddy current retarder (RECR) and the RGB, both of which share a stator. Braking torque of the IEER produced by stator core and armature-windings can stack together, and therefore the IEER can provide greater braking torque than the RECR. Besides, the IEER can recover electric energy from armature-windings.
Technical Paper

Downhill Safety Assistant Driving System for Battery Electric Vehicles on Mountain Roads

2019-09-15
2019-01-2129
When driving in mountainous areas, vehicles often encounter downhill conditions. To ensure safe driving, it is necessary to control the speed of vehicles. For internal combustion engine vehicles, auxiliary brake such as engine brake can be used to alleviate the thermal load caused by the continuous braking of the friction brake. For battery electric vehicles (BEVs), regenerative braking can be used as auxiliary braking to improve brake safety. And through regenerative braking, energy can be partly converted into electrical energy and stored in accumulators (such as power batteries and supercapacitors), thus extending the mileage. However, the driver's line of sight in the mountains is limited, resulting in a certain degree of blindness in driving, so it is impossible to fully guarantee the safety and energy saving of downhill driving.
Technical Paper

Driving Fatigue Detection based on Blink Frequency and Eyes Movement

2017-03-28
2017-01-1443
The development of the vehicle quantity and the transportation system accompanies the rise of traffic accidents. Statistics shows that nearly 35-45% traffic accidents are due to drivers’ fatigue. If the driver’s fatigue status could be judged in advance and reminded accurately, the driving safety could be further improved. In this research, the blink frequency and eyes movement information are monitored and the statistical method was used to assess the status of the driving fatigue. The main tasks include locating the edge of the human eyes, obtaining the distance between the upper and lower eyelids for calculating the frequency of the driver's blink. The velocity and position of eyes movement are calculated by detecting the pupils’ movement. The normal eyes movement model is established and the corresponding database is updated constantly by monitoring the driver blink frequency and eyes movement during a certain period of time.
Technical Paper

Driving Path Planning System under Vehicular Active Safety Constraint

2016-09-27
2016-01-8105
Path planning system, which is one of driver assistance systems, can calculate the driving paths and estimate the driving time through the road information provided by information source. Traditional path planning systems calculate the driving paths through Dijsktra's algorithm or A* algorithm but only consider the road information from electronic maps. It is not safe enough for operating vehicles because of the insufficient information of vehicle performance as well as the driver's willingness. This study is based on the Dijsktra's algorithm, which comprehensively considered vehicular active safety constraints such as road information, vehicle performance and the driver's willingness to optimize the Dijsktra's algorithm. Then the path planning system can calculate the optimal driving paths that would satisfy the safety requirement of the vehicle. This study used LabVIEW as a visual host computer and MATLAB to calculate dynamic property of the vehicle.
Technical Paper

Effect of Circumferential Magnetic Field on Braking Performance of a Direct Vane Magnetorheological Fluid Retarder

2019-04-02
2019-01-0342
The hydraulic retarder used in commercial vehicles can provide hydraulic damping to generate braking torque, reducing the pressure of the braking system on the slope section and increasing the safety. In this paper, the magnetorheological fluid with fast magnetic field reflection characteristics is used to increase the response speed of the hydraulic retarder, which can effectively reduce the response time of the hydraulic retarder. In this paper, the influence of the change of circumferential magnetic field on the braking torque of the magnetorheological fluid retarder is studied.
Technical Paper

Effect of Temperature on Braking Efficiency Stability of Magnetorheological Fluid Auxiliary Braking Devices

2017-09-17
2017-01-2510
Fluid auxiliary braking devices can provide braking torque through hydraulic damping, fluid auxiliary braking devices can also convert vehicular inertia energy into transmission fluid heat energy during the braking, which can effectively alleviate the work pressure of the main brake. Traditional hydraulic auxiliary braking devices use transmission fluids to transmit torque, however, there is a certain lag effect during the braking. The magnetorheological fluid (MR fluid) can also be used to transmit torque because it has the advantages of controlling braking torque linearly and responding fast to the magnetic field changed. The temperature of MR fluid will increase when the vehicle is engaged in continuous braking. MR fluid temperature changes will cause a bad influence on the efficiency stability of auxiliary braking.
Technical Paper

Effect of stator surface area on braking torque and wall heat dissipation of magnetorheological fluid retarder

2020-04-14
2020-01-0937
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.
Technical Paper

Experiment Study and Design of Self-excited Eddy Current Retarder

2013-11-27
2013-01-2825
Good braking performance is an important guarantee for the vehicle driving. In the condition of frequent or prolonged braking, the overheating problem for the traditional mechanical braking device causes the recession of the braking performance, which is a prominent problem especially for the commercial vehicle perennial traveling in the mountains. Eddy current retarder can reduce the mechanical brake load as a kind of auxiliary braking device. Thus, the temperature of the mechanical braking device would not be too high, and the traveling safety of the vehicle can be ensured. But eddy current retarder would cause an enormous impact for automobile battery when it starts up and huge electricity energy would be consumed which means that more automotive batteries are needed. Considering above, a kind of self-excited eddy current retarder is developed in the paper.
Technical Paper

Fuel-Efficient Driving for Motor Vehicles Based on Slope Recognition

2017-03-28
2017-01-0037
The drivers' hysteretic perception to surrounding environment will affect vehicular fuel economy, especially for the heavy-duty vehicles driving under complex conditions and long distance in mountainous areas. Unreasonable acceleration or deceleration on the slope will increase the fuel consumption. Improving the performance of the engine and the transmission system has limited energy saving potential, and most fuel-efficient driving assistant systems don't consider the road conditions. The main purpose of this research is to introduce an economic driving scheme with consideration of the prestored slope information in which the vehicle speed in mountainous slopes is reasonably planned to guide the driver's behavior for reduction of the fuel consumption. Economic driving optimization algorithm with low space dimension and fast computation speed is established to plan accurate and real-time economic driving scheme.
Technical Paper

Kalman Filter Slope Measurement Method Based on Improved Genetic Algorithm- Back Propagation

2020-04-14
2020-01-0897
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.
Technical Paper

Microwave-Steam Based Road Deicing Vehicle Focused on Thin Ice Layers

2015-04-14
2015-01-0502
For the thin ice on the road in winter, the traditional road deicing vehicle relies on mechanical and chemical methods for melting ice, which is inclined to damage the pavement and has insidious influence on environment. The thermal deicing vehicle has been adopted in recent years. Although the deicing method is available, the deicing efficiency is unacceptable while the energy consumption is huge. The study adopts the new idea of “bottom-to-top” for melting the intersection area between the road surface and the bottom ice layer by the microwave heating firstly and then cleaning them out using high pres. vapor cutting so as to save the cost of energy and enhance the traffic safety. First of all, the mathematical model of the melting process of the intersection of the pavement and the ice layer was established according to the microwave heating characteristics.
Technical Paper

Optimal Management of Charge and Discharge of Electric Vehicles Based on CAN Bus Communication

2020-04-14
2020-01-1297
With the shortage of energy and the continuous development of automotive technology, electric vehicles are gradually gaining popularity. However, during the running of the electric vehicle, there is a risk of exhaustion of the electric power, and the position of the charging pile is fixed, which is likely to cause anxiety and worry of the owner. At present, there is a lack of an effective energy consumption prediction system, which is convenient for the driver to make reasonable driving planning guidance. As a standard serial communication protocol of ISO, CAN bus has a simple structure, short development cycle, stability and reliability. In this paper, the CAN bus is used to extract the dynamic parameter information of the speed, engine speed and throttle opening of the traveling vehicle in real time.
Technical Paper

Parameter Optimization of Anti-roll Bar Based on Stiffness

2020-04-14
2020-01-0921
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.
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