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Viewing 1 to 30 of 7397
Technical Paper
2014-09-30
Dhiraj Dashrat Salvi
ABSTRACT- Braking system is having a key importance in vehicle safety & handling stability. In this research paper I had developed a circuit model of Anti-lock braking system where the operating medium is hydra-pneumatic. A solenoid operated modulator valve consisting two 2/2 valves is connected in line with the air cylinder & hydraulic master cylinder assembly. Using methodology of response time calibration time taken to modulate hydraulic pressure w.r.t pneumatic pressure is evaluated. The signal input to the modulator valve is given by the Electronic controlled input (ECU). All results obtained is exported to an excel file using Data Acquisition software with pressure myograph system. It gives easy and intuitive readings based on the signal programmed from ECU for various inputs (i.e. ramp, step) .The signal are programmed for various inputs in order to check the fidelity of the circuit. These readings are easily customized to get the optimum graphs. The response time evaluated from the calibrated data is compared with benchmark or standard set by CMVR to meet the regulation.
Technical Paper
2014-09-30
Can Wang, Gangfeng Tan, Bo Yang, Ming Chen, Fudong Wei, Yabei Ni
The hydraulic retarder, which is an auxiliary brake device for enhancing traffic safety, has been widely used in kinds of heavy commercial vehicles. When the vehicle equipped with the retarder is traveling in non-braking state, the transmission loss would be occurred because of the stirring air between working wheels of the rotor and the stator no matter the retarder connects in parallel or in series with the transmission. This paper introduces an elaborate hydraulic retarder air-friction reduction system (AFRS) which consists of vacuum generating module and gas control module. AFRS works by decreasing the gas density between working wheels when the retarder is in non-braking state. The gas path model of hydraulic retarder is built first and then the working stability of the AFRS is analyzed in various driving conditions based on ensuring the normal braking of the retarder. Functional relations between air density and air friction in the working wheel are determined by means of 3D fluid simulation and the vacuum power and the air friction are analyzed comprehensively.
Technical Paper
2014-09-30
Sunil raj, S Ravi Shankar
Braking system is one of the very important in the automotive system. The purpose of the braking system is to stop or slow the vehicle when required. Deceleration of the vehicle is done due to the friction between Brake drum and Brake lining. Brake drum converts kinetic energy into heat energy and it dissipates the heat. The amount of heat depends on the weight of the vehicle and speed at the moment the brakes are applied. The brake drum material must be able to dissipate the heat as much as possible and to resist the high thermal stresses generated during repeated thermal cycling. Traditionally brake drums are manufactured using grey cast iron to meet thermal conductivity and vibration damping characteristics resistance to thermal shock and cycling, wear resistance and easy of production. The main purpose of using grey cast iron in brake drum is because it has good thermal conductivity property and wear resistance. Aluminum is the other metal which has better thermal conductivity compared to cast iron but it has very bad wear resistance compared to grey cast iron.
Technical Paper
2014-09-30
Hongyu Zheng, Linlin Wang
The condition of the brake pad wear depends greatly on the distribution of braking force and the type of brakes, so the wear conditions are usually different. From the perspective of braking force distribution, 60% braking force is distributed to the rear axle on a bus, leading to greater wear on the rear axle. While from the perspective of brake types, the brake pad on the front axle will have a greater wear if brake discs are applied to the front axle and drum brakes are applied to the rear axle. Different wear conditions make it impossible to replace all brake pads at the same time, which increases the time and cost needed in repair and maintenance. Both the deceleration of vehicle and optimum distribution of braking force depend on load conditions. The decoration control algorithm of EBS makes the total braking force proportional to the mass of the vehicle, which makes the braking performance independent from the load conditions when using the same pedal operation. Then the total braking force is distributed to each wheel based on the dynamic wheel load to make the adhesion utilization of each axle equal.
Technical Paper
2014-09-30
Anudeep K. Bhoopalam, Corina Sandu, Saied Taheri
Safety and minimal transit time are vital during transportation of essential commodities and passengers, especially during winter conditions. Icy roads are the worst driving conditions with the least available friction leaving valuable cargo and precious human lives at stake. This study investigates the available friction at the tire-ice interface due to changes in key operational parameters. Experimental analysis of tractive performance of tires on ice was carried out indoor, using the terramechanics rig located at the Advanced Vehicle Dynamics Laboratory (AVDL) at Virginia Tech. The friction-slip ratio curves were also generated from model simulations and compared to the experimental findings from the terramechanics rig. The shortcomings of simulations in considering all the effects of all the operational parameters result in a difference in the friction values obtained by the two methods. Thus, arises the need for state-of-the-art tire-ice models capable of predicting accurate friction levels taking into account all operational conditions.
Technical Paper
2014-09-30
Dong Zhang, Changfu Zong, Guoying Chen, Pan Song, Zexing Zhang
This paper mainly focuses on the dynamic characteristics and control methods for drive-by-wire electric vehicle. In this paper, the system architecture of the full drive-by-wire electric vehicle is proposed, which vehicle control unit is based on a rapid control prototyping. The X-by-wire electric vehicle is developed with four wheels independently steered, driven by in-wheel motors, braked by electromagnetic brakes and controlled by active suspensions. To identify and classify the drivers’ characteristics, the MDHMM is established by utilizing HMM and Baum-Welch algorithms. A double layer HMM is used to conduct onboard identification according to the driver’s inputs, environmental information and vehicle states. And real-time ideal reference models of vehicle dynamics for different characteristic drivers are built up with RBF neural network technique by using the driving simulator test data, which use dynamics control for the electric vehicle. For a full drive-by-wire electric vehicle, the wheel speed and braking torques of each wheel can be readily obtained.
Technical Paper
2014-09-30
Guoying Chen, Dong Zhang
Four-wheel independent control electric vehicle is a new type of x-by-wire vehicle with four wheels independent steering and four wheels independent drive/brake systems. Due to the superiority of its structure, the vehicle can perform some special actions that conventional vehicles couldn’t complete, such as zero radius turning, oblique driving and crab. These greatly improve the mobility of four-wheel independent control electric vehicles under low speed condition. Furthermore, the vehicle could get better handing stability by the integrated chassis control for steering and drive/braking systems. So in the paper we try to study the integrated chassis control on how to optimally distribute the angles/torque of each wheel of four-wheel independent control electric vehicle that maximizes the used of the friction between tire and road. In order to introduce the vehicle integrated chassis control clearly, this paper is divided into four parts. In part one, the control targets and the hierarchical control structure of the integrated chassis controller are described.
Technical Paper
2014-09-30
Boris Belousov, Tatiana I. Ksenevich, Vladimir Vantsevich, Sergei Naumov
An open-link locomotion module (OLLM) is considered as autonomous energy self-sufficient locomotion setup for designing ground wheeled vehicles of a given configuration including the number of the drive/driven and steered/non-steered wheels with individual suspension and brake systems. The paper concentrates on the module’s electro-hydraulic suspension design and presents results of analytical and experimental studies. The suspension design provides the sprung mass with sufficient vibration protection at low level of normal oscillations, enhanced damping and stabilized angular movements on highly non-even terrain. This is achieved by the introduction of two control loops: (i) a fast-acting loop to control the damping of the normal displacements; and (ii) a slow-acting control loop for varying the pressure and counter-pressure in the suspension system. Thus, two separate but coordinated controls were designed for both loops to act under small (less than ±7 degrees) and big (larger than ±7 degrees) pitch and roll angles of a vehicle designed with a set of the modules.
Technical Paper
2014-09-30
Xianjian Jin, Guodong Yin, Youyu Lin
Knowledge of vehicle dynamics variables is very important for vehicle control systems that aim to improve handling characteristics and passenger safety. However for both technical and economical reasons some fundamental data (e.g., Lateral tire-road forces and vehicle sideslip angle) are not measurable in a standard car. This paper proposes a novel Interacting Multiple Model Filter-Based method to estimate lateral tire-road forces by utilizing real-time measurements. The method uses measurements (yaw rate, roll rate, accelerations, steering angle and wheel speed) only from sensors which have already been integrated in modern cars. The estimation method of lateral tire-road forces is based on an interacting multiple model (IMM) filter that integrates in-vehicle sensors of in-wheel-motor-driven electric vehicles to adapt multiple vehicle-road system models to variable driving conditions. Considering extended roll dynamics and load transfer, a four-wheel nonlinear vehicle dynamics model (NVDM) is built.
Technical Paper
2014-09-30
Iman Hazrati Ashtiani, Mehrnoosh Abedi
Road trains have been applied as one of the efficient ways for transportation of goods in different countries like United States, Canada, Brazil and Australia. These long vehicles have a wide variety in length or towing systems like fifth wheel or dolly draw-bar and based on specific measured and regulation could be authorized to move in specific roads. In order to avoid hazard and danger in case of accidents of these vehicles, safety performance of a specific type of these vehicles, called B-train, is investigated in this paper. A Multi-Body Dynamics (MBD) model of a B-train, which consists of a prime mover and two trailers coupled by fifth wheels, are simulated in first phase of study. The developed dynamic model is capable of simulating required tests as well as SAE lane change and constant radius turn for roll and yaw stability analysis and safety evaluation. As far as transportation of fuel or other hazardous liquid are a common usage of B-train vehicles, the effects of liquid fill level variation are also considered in this research.
Technical Paper
2014-09-30
Vladimir V. Vantsevich, Jeremy P. Gray, Dennis Murphy
Through inverse dynamics-based modeling and computer simulations for a 6x6 unmanned ground vehicle in stochastic terrain conditions, this paper analytically presents a coupled impact of different driveline system configurations and a suspension design on vehicle dynamics, including vehicle mobility and energy efficiency. A new approach in this research work involves an estimation of each axle contribution to the level of potential mobility loss/increase and/or energy consumption increase/reduction. As it is shown, the drive axles of the vehicle interfere with the vehicle’s dynamics through the distribution of the wheel’s normal reactions and wheel torques. The interference causes the dynamics of the independent systems to become operationally coupled/fused, and thus diminishes the vehicle’s mobility and energy efficiency. The analysis is achieved by the use on new mobility indices and energy efficiency indices which are functionally coupled/fused. Four possible scenarios are considered to trade between mobility and energy efficiency improvements by re-distributing power between the drive axles in severe/extreme terrain conditions, including poor mu-conditions, and high longitudinal and lateral slopes.
Technical Paper
2014-09-30
Yiting Kang, Subhash Rakheja, Wenming Zhang
Different types of axle suspension systems have evolved for large size mining trucks to achieve improved attenuation of terrain-induced whole-body vibration (WBV) transmitted to the operator and to attain higher operating speeds. The hydro-pneumatic struts are increasingly being used together with different linkage configurations, which could yield widely different kinematic and dynamic properties and thereby the ride and handling performance of the vehicle. This paper presents comprehensive analyses of the different independent front suspension linkages that have been implemented in various off-road vehicles, namely a composite linkage Macpherson strut type suspension (CLT), a candle type suspension (CT), a longitudinal arm type suspension (LAT), and a double wishbone type suspension (DWT). The relative performance analyses are evaluated on the basis of handling dynamics of a 190 tons mining truck. The kinematic variations in camber, caster, inclination angle, toe-in and horizontal wheel center displacements of different linkage suspensions are synthesized via wheel bounce excitations in the MapleSim platform.
Technical Paper
2014-09-30
James Chinni, Robert Butler, Shu Yang
Federal Motor Carrier Safety Requirement (FMCSR) 393.76(h) states that “a motor vehicle manufactured on or after July 1, 1971 and equipped with a sleeper berth must be equipped with a means of preventing ejection of the occupant of the sleeper berth during deceleration of the vehicle.” [1] Today, sleeper berths are equipped with sleeper restraint systems that function to contain the sleeper occupant inside the sleeper berth during reasonably foreseeable crashes. To assess the effectiveness of sleeper restraint systems, computer simulation models of the sleeper cab environment and these restraint systems was developed, with a simulated supine occupant in the sleeper. The model was evaluated using two different rollover crash scenarios. The first rollover scenario used measurements from a previously reported tractor-trailer, driver side leading, quarter-turn rollover crash test. The second rollover scenario was based on reconstruction of a very severe crash that occurred on a mountain road, where a tractor-trailer rolled, passenger side leading.
Technical Paper
2014-09-30
Massimiliano Ruggeri, Carlo Ferraresi, Luca Dariz, Giorgio malaguti MD
The world of electronics is rapidly changing due to the new functional safety regulations, both for Construction Equipments and for Agricultural Machines. From the 2014 the new ISO4254 recalls the ISO25119, applying the functional safety to all Agricultural machines other than Tractors. But Tractors will be involved in new functional safety requirements from 2016, being analyzed under the ISO25119 statements. Functional safety requirements and solutions are more expensive in proportion for small machines: lower cost machines with less power but same functionalities with respect to the big machines. The paper will show a real electronic control unit design of a machine controller, controlling both engine working point, transmission, and other utilities like PTO, 4WD, brakes and Differential Lock; the Electronic Control Unit (ECU) was designed in accordance to ISO 25119 regulation, to meet AgPL = C or even D for some functionalities. The unit is a fully redundant electronic control unit with two CAN networks and some special safe state oriented mechanism, that allow the Performance Level C with less software analysis requirements compared with traditional solutions.
Technical Paper
2014-09-30
Raghuram Krishnamurthy, Dr. Rani Mukherjee
Safety compliance has a new set of difficult questions to address due to the usage of COTS, OSS and externally supplied software code in automotive systems. The use of third-party software component is essential to business as it helps in reduction of cost and development cycle. However, there are many technical risks encountered when incorporating Third-Party Software (TPSW) components into safety related software. Moreover, safety systems conforming to new automotive safety standard ISO 26262 are expected to satisfy criteria for co-existence of TPSW with internal safety related software and legacy code. The purpose is to avoid a potential failure that may be triggered by TPSW which in turn may propagate to cause failure in other software partitions. There are several options available to address the above requirements. We should carefully evaluate the TPSW’s functionality and pedigree and apply combination of techniques to assist in supporting the intent of ISO 26262. This paper discusses on the issues concerning insertion of third party software code (OEM supplied code, Tier 2 vendor software) into in-house developed ECU software.
Technical Paper
2014-09-30
James Chinni, Ryan Hoover
Full-scale vehicle crash testing is an accurate method to reproduce many real-world crash conditions in a controlled laboratory environment. However, the costs involved in performing full-scale crash tests can be prohibitive for some purposes. Dynamic sled testing is a lower cost and widely used method to obtain multiple useful data sets for development of frontal crash mitigating technologies, systems and components. Wherever possible, dynamic sled tests should use vehicle-specific deceleration pulses determined from full-scale vehicle crash tests. This paper establishes a dynamic sled test protocol based on data collected from a small number of full-scale heavy vehicle frontal crash tests. The sled test protocol is intended to be utilized as a basis for building a body of knowledge needed to update heavy vehicle frontal impact test recommended practices. These recommended practices provide direction for the development of frontal crash mitigating technologies, systems and components.
Technical Paper
2014-09-30
Takahiko Yoshino, Hiromichi Nozaki
In the present paper, we investigate the possibility of improving the maneuverability and stability, e.g., cornering behavior under large lateral acceleration, of vehicles by controlling not only the steer angle but also the camber angle. It possible to improve the marginal performance of vehicle dynamics effect of camber thrust force. In the total skid margin, no margin remains in the tires’ front/rear power regardless of the braking/driving force that is applied, and no performance improvement can be expected. We believe that, by proactively controlling the tire camber angle in relation to the steering angle, we can substantially improve maneuverability and stability in the critical range to a greater degree than with 4WS or direct yaw moment control. In an attempt to improve maneuverability and stability in the critical cornering ranges, the present study focused on negative camber angle control proportional to steering and examined its effectiveness through numerical computations using a tire model, through a camber angle control experiment with a model car, and through a simulation using a vehicle model.
Technical Paper
2014-09-30
Prashant Shinde, Pratik Gore
This paper is an attempt to address and simplify the root cause of catastrophic failures caused by incidents of fire and smoke in commercial vehicles during last few years in China and India. With the advancement of new features in automotive industry, ruinous failures of commercial vehicles, public transport buses have also increased a lot resulting in a considerable number of casualties. Some of the accidents encountered happened because of a crash with fire originating from the fuel tank. An ECU for preventing such fire-mishaps shall be designed for spotting this failure and activating prevention methods in order. It has been observed that the main reason behind these fire-mishaps was burning of fuel tank because of leakage and excessive heat produced due to friction of debris with the fuel tank which happened within a few seconds of the crash. This safety-critical ECU shall process real-time data coming from thermal-sensor and pressure sensor placed on vehicle fuel tank. This real-time data shall be compared with the previously processed values and then the delta-differentiated value shall be used to conclude the likelihood of fire-occurrence.
Technical Paper
2014-09-30
Hongyu Zheng, Linlin Wang
With the development of highway, the road transportation industry flourishes based on heavy duty vehicle. The wide application of heavy duty vehicle improves the efficiency of road transportation and reduces the cost of goods-delivery. While the heavy duty vehicle has a higher gravity-center, larger loads and relatively narrow tread in comparison with the height of vehicle. Therefore the stability of heavy duty vehicle and semitrailer often causes occurrence of rollover, swing, and jackknife. For years the accidents of heavy vehicles are in a status of high frequency and how to solve the problem of stability and safety of heavy duty vehicle has become a key factor in road transportation industry. At present, there are three stability loss situations which are rollover, trail swing and jackknife, have often happened by bus, tractor and trailer. By reviewing the previous research, the stability of tractor and trailer has been put into categories that yaw stability and roll stability control algorithms have been studied [3], [4].
Technical Paper
2014-09-30
Hongyu Zheng, Linlin Wang
Strong federal initiatives for increasing the efficiency and safety of today’s vehicle, and marketing strategies in industry, has motivated extensive research.Heavy duty vehicles have received particular attention due to the higher impact that automation has on the fleet efficiency and fuel economy.An heavy-duty vehicle’s mass can vary significantly from trip to trip.Trailer mass estimation is essential to optimize the relevant braking force distribution on both tractor and trailer.Directing at the poor compatibility between tractor and trailer and the braking impulse during the braking process,the paper proposes a mass-based braking force distribution algorithm for the electronic braking system.As a result ,coupling forces between tractor and trailer are kept to a minimum, so that negative effects on the stability can be excluded. To simplify the exposition of the approach,the algorithm neglects the BAS’s influence.Algorithm estimates the real-time vehicle mass during the process of building up the braking force.When the braking deceleration is less than a certain value ,the algorithm repeat the estimation process.Vehicle mass is equal to the mean value of the several mass values estimated by the algorithm.Electronic braking system(EBS) applies the estimated mass into distributing the braking force,keeping the agreement of the deceleration of the tractor and trailer ,reducing the braking impulse and improving the compatibility between tractor and trailer.The algorithm can be validated through the actual vehicle model in the software Trucksim and Matlab.
Technical Paper
2014-09-30
Linlin Wang, Hongyu Zheng
Aimed at enhancing the vehicle safety and improving the braking performance, a slip-rate-based braking force distribution algorithm is proposed for the electronic braking system of combination vehicle. In the algorithm the slip rates of the tractor’s rear wheels and the semi-trailer’s wheels change with the slip rate of the tractor’s front wheels, making tractors’ front wheels lock up ahead of the tractor’s rear wheels and the semi-trailer’s wheels The algorithm can be tested by co-simulation with Matlab/Simulink and Trucksim software on vehicle running both on high and low adhesion roads. The detailed algorithm can be elaborated as follows: The signals of the wheels’ speed and angular acceleration form the sensors are sent to the ECU. In order to simplify the calculating process, the vehicle speed can be evaluated as the maximum of the speeds of the six wheels. A threshold is set for the tractors’ rear wheels and the semi-trailer’s wheels when the slip rates change with the slip rates of the tractors’ front wheels so that the adhesion coefficient can be made best of.
Technical Paper
2014-09-30
Takahiko Yoshino, Hiromichi Nozaki
It has been reported that steering systems with derivative terms have a heightened lateral acceleration and yaw rate response in the normal driving range. However, in ranges where the lateral acceleration is high, the cornering force of the front wheels decreases and hence becomes less effective. Therefore, we applied traction control for the inner and outer wheels based on the steering angle velocity to improve the steering effectiveness at high lateral accelerations. An experiment using a driving simulator showed that the vehicle’s yaw rate response improved for a double lane change to avoid a hazard; this improves hazard avoidance performance. Regarding improved vehicle control in the cornering margins, traction control for the inner and outer wheels is being developed further, and much research and development has been reported. However, in the total skid margin, where no margin remains in the forward and reverse drive forces on the tires, spinout is unavoidable. Therefore, we applied tire camber angle control to improve vehicle maneuverability in the total skid margin.
Technical Paper
2014-09-28
Liang Zhou, Chuqi Su
In this paper,a strategy for recovery of braking energy in HEV with EMB is proposed, which is less limited to the performance of the 42V vehicle power supply, compared with the conventional recycling strategy without EMB. In the traditional HEV with 42V vehicle power supply, recovery of braking energy is mainly recycled to the 42V battery, directly. As charging current is too large, or charging time is too long can damage the battery, 42V battery is difficult to recycle braking energy effectively ,especially in complex urban condition with vehicle braking frequently and rapidly. But in HEV with EMB,the recovery transfers to the motor of EMB directly, which is utilized dynamically in the process of vehicle braking. Excess electricity transfers to the energy storage unit if the generator is performing a voltage higher than the required voltage of EMB brake motor, otherwise, the energy storage unit to supplement electricity. The kinetic energy of the HEV turned into electrical energy to EMB timely,rather than being stored statically in this process.
Technical Paper
2014-09-28
Michael Herbert Putz, Christian Wunsch, Markus Schiffer, Jure Peternel
With linear actuated brakes the actuation force (or actuation torque) rises linearly from 0 to the full actuation force at full braking, causing a very variable motor current. The electro-mechanical brake (EMB) of Vienna Engineering (VE) uses a highly non-linear mechanism to create the high pressing force of the pad. The advantage is that the pad moves very fast when the pad pressing force is low and moves slower with increasing pressing force. This non-linear actuation means that the motor is always running at relatively constant load (although the pad pressing force changes highly), resulting in a motor that can be optimized for constant torque and constant rpm, reducing size and costs and increasing efficiency. The normal force in EMBs is often controlled by observing mechanical deformation to conclude to stress or force, commonly using strain gauges. It causes costs of the gauge itself and attaching them to e.g. the caliper and a sensitive amplifier. The full gauge equipment goes into the safety-related brake control system.
Technical Paper
2014-09-28
Zhizhong Wang, Liangyao Yu, Yufeng Wang, Kaihui Wu, Ning Pan, Jian Song, Liangxu Ma
The Distributed Electro-hydraulic Braking System (DEHB) is a wet type brake-by-wire system for passenger vehicles, and is especially suitable for electric vehicles and hybrid electric vehicles. The basic DEHB comprises four independent brake actuators connected to four hydraulic brakes. The word ‘distributed’ refers to the distributed arrangement of the brake actuators on the vehicle. Each brake actuator comprises an electric motor to provide brake power, a mechanism to translate rotational motion of the motor shaft into translational motion of a piston. The piston moves back and forth in a cylinder under the control of the motor to push the brake fluid into the brake. In this way, braking pressure can be controlled by the motor. Like other brake-by-wire systems, brake pedal simulator and pedal sensors are also used in DEHB. Although the concept of DEHB traces back to 1990s, only a few research papers can be found. This paper gives a review and outlook on the design concepts of DEHB from the following three aspects. 1.
Technical Paper
2014-09-28
Alberto Boretti, Stefania Zanforlin
Real driving cycles are characterized by a sequence of accelerations, cruises, decelerations and engine idling. Recovering the braking energy is the most effective way to reduce the propulsive energy supply by the thermal engine. The fuel energy saving may be much larger than the propulsive energy saving because the thermal engine energy supply may be cut where the engine operates less efficiently and because the thermal engine can be made smaller. The present paper discusses the state of the art of hydro-pneumatic driveline now becoming popular also for passenger cars and light duty vehicle applications.
Technical Paper
2014-09-28
Dongmei Wu, Haitao Ding, Konghui Guo, Yong Sun, Yang Li
With the promotion of electric vehicles, their stability control problem has become increasingly important. Four-wheel-drive electric vehicle can not only control the vehicle stability through hydraulic braking pressure regulation, but also through controlling the motor driving and braking force to generate yaw moment , which are different with the conventional vehicles. In addition, the hydraulic braking system of four-wheel-drive electric vehicle is Electro-Hydraulic Braking System (EHB), rather than the conventional hydraulic braking system. With EHB, the braking pressure in four wheel cylinders can be controlled independently and flexibly, rather than depending on the braking pedal. Besides, there are also several pressure sensors in EHB, which can supply the wheel cylinder pressure information, without the need for pressure estimation. As a result, the way to achieve stability control of four-wheel drive electric vehicle will be different with conventional vehicle. Currently, there are not many researches on the stability control of four-wheel-drive electric vehicle with EHB, and most of them are still at the stage of virtual simulation, lacking testing and applications in real system.
Technical Paper
2014-09-28
Jongsung Kim, Chjhoon Jo, Yongsik Kwon, Jae Seung Cheon, Soung Jun Park, Gab Bae Jeon, Jaehun Shim
Electro-Mechanical Brake (EMB) is the brake system that is actuated by the electrical energy and the motor rotation. It has similar design with Electro-Mechanical Parking Brake (EPB). It uses the gear multiplication structure for the enough torque and screw/nut mechanism for changing rotational movement to linear. The differences with EPB are screw/nut and motor type and some specification of the inner parts because the needed performance of the service braking like braking time is much higher than EPB, and usually EMB includes the force sensor for controlling the actuator and solenoid-lever structure for EPB function. The highly responsive and independent brake actuators lead to enhanced controllability which should result in not only better basic braking performance, but also improvements in various active braking functions such as integrated chassis control, driver assistance systems, or cooperative regenerative braking. Although the EMB system has the potential for numerous advantages and innovations in braking, it has yet to be successfully introduced in series production mainly due to safety and cost concerns.
Technical Paper
2014-09-28
Lu Xiong, Bing Yuan, Xueling Guang, Songyun Xu
At the very beginning part, a detailed analysis on current status of electro-hydraulic brake system is carried out. By analyzing 28 electro-hydraulic brake systems, the paper provides a brief summarization on structural components of typical electro-hydraulic brake systems from the perspective of main functional units. Then a more in-depth analysis is conducted on the key functional units, particularly on Active pressure-building unit and Pedal simulation unit. For instance, in terms of Active pressure-building unit, electro-hydraulic brake system schemes can be divided into two categories according to active power sources: one is pump + high-pressure accumulator, the other electric motor+ reducing mechanism. Then author employs MK C1, the latest electro-hydraulic brake system launched by Continental AG, to illustrate its structural components and working principle. In the second part, the idea of dual-motor electro-hydraulic brake system is proposed. As a new solution, dual-motor electro-hydraulic brake system can actively simulate pedal feeling and merge pedal power (from the driver ) into braking power at the same time, which is a distinctive innovation compared to most current electro-hydraulic brake systems.
Viewing 1 to 30 of 7397