Conventional Braking System Research Articles

An Engine/Vehicle Model to Assess the Theoretical Increase of Car Safety by Using the Spark Ignition Engine to Support the Conventional Braking System

An Engine/Vehicle Model to Assess the Theoretical Increase of Car Safety by Using the Spark Ignition Engine to Support the Conventional Braking System

An Engine/Vehicle Model to Assess the Theoretical Increase of Car Safety by Using the Spark Ignition Engine to Support the Conventional Braking System

Introduction of active safety systems has led to a significant increase of passenger car safety. However, statistics on road accidents show that further improvements of active systems would be necessary. This paper presents a dynamical model of the engine–car–brakes system that is used to simulate vehicle deceleration and calculate the risk of injuries. The model is used to quantify the performance of active safety systems during specific collision scenarios in which several vehicle cruising speeds and different values of distance from the obstacle that causes the active system activation are considered. The base system constituted by actual hydraulic brakes with embedded ABS is first compared to the ideal active system. The latter allows for maximum vehicle deceleration owing to ideal operation of hydraulic brakes supported by ABS and also to mechatronic actuation which anticipates the human intervention and eliminates the delay due to reaction time. Then, the model is used to analyse two feasible evolutions of the ideal active safety system. In the first one, the internal combustion engine friction power aids the vehicle speed decrease before the action of brakes. In the second one, specifically devoted to vehicles powered by hybrid electrical–thermal units, the reversible electric motor operates in addition/substitution to the braking action exerted by the engine mechanical friction.

An Engine/Vehicle Model to Assess the Theoretical Increase of Car Safety by Using the Spark Ignition Engine to Support the Conventional Braking System

Introduction of active safety systems has led to a significant increase of passenger car safety. However, statistics on road accidents show that further improvements of active systems would be necessary. This paper presents a dynamical model of the engine–car–brakes system that is used to simulate vehicle deceleration and calculate the risk of injuries. The model is used to quantify the performance of active safety systems during specific collision scenarios in which several vehicle cruising speeds and different values of distance from the obstacle that causes the active system activation are considered. The base system constituted by actual hydraulic brakes with embedded ABS is first compared to the ideal active system. The latter allows for maximum vehicle deceleration owing to ideal operation of hydraulic brakes supported by ABS and also to mechatronic actuation which anticipates the human intervention and eliminates the delay due to reaction time. Then, the model is used to analyse two feasible evolutions of the ideal active safety system. In the first one, the internal combustion engine friction power aids the vehicle speed decrease before the action of brakes. In the second one, specifically devoted to vehicles powered by hybrid electrical–thermal units, the reversible electric motor operates in addition/substitution to the braking action exerted by the engine mechanical friction.

Enhanced Electromechanical Brake-by-Wire System Using Sliding Mode Controller

The importance of the brake-by-wire (BBW) system emerged from the fact that it replaces all the conventional hydraulic braking system components with electronic signals between sensors, control modules, and electrically driven braking actuators. This conversion has enormously contributed to the braking system performance in terms of responsiveness, integration with other vehicle subsystems, and an adaptive behavior in different driving circumstances. The aim of this research is investigating the sliding mode control (SMC) strategy to a proposed BBW system. To achieve this aim, BBW system is modeled and validated experimentally. The SMC strategy is applied to the model and validated experimentally. Moreover, this research focuses on compensating for the effect of worn pads on braking performance. The experimental work shows that the developed system model gives matched results with the experimental work. Applying SMC to the model shows a good performance in breaking operation with acceptable error. Applying of the SMC to the test rig shows a good performance with acceptable deviations. In addition, the experiments show that the control strategy is able to compensate the wear in braking pads and keep tracking the braking command.

Electric vehicle dynamics control during electrical system faults

This paper focuses on a propulsion concept for electric vehicles (EVs). The considered actuators consisting of permanent magnet synchronous machines and the conventional hydraulic braking system are mounted on the rear axle of the vehicle and offer new degrees of freedom in vehicle motion control. The proposed control structure consists of cascaded feedback loops for wheel slip, yaw rate and sideslip angle and accesses these actuators concurrently. The focus of the present work is on possible machine/inverter faults. Two characteristic electrical system faults are described, and their impacts on vehicle stability are investigated. It is shown how the proposed vehicle motion controller can preserve driving safety even in the presence of electric system faults. The consequences on vehicle motion are discussed in detail.

Full-scale testing of a novel slip control braking system for heavy vehicles

This paper summarises the measured emergency braking performance of a tri-axle heavy goods vehicle semitrailer fitted with a novel pneumatic slip control braking system developed by the Cambridge Vehicle Dynamics Consortium. Straight-line braking tests were carried out from 40 km/h in order to compare a commercially electro-pneumatic available anti-lock braking system and the Cambridge Vehicle Dynamics Consortium system, which has bi-stable valves coupled with a sliding-mode slip controller. On average, the Cambridge Vehicle Dynamics Consortium system reduced the stopping distance and the air use by 15% and 22% respectively compared with those for the conventional anti-lock braking system. The most significant improvements were seen on a wet basalt-tile surface (with similar friction properties to ice) where the stopping distance and the air use were improved by 17% and 30% respectively. A third performance metric, namely the mean absolute slip error, is introduced to quantify the ability of each braking system to track a wheel slip demand. Using this metric, the bi-stable valve system is shown to improve the wheel slip demand tracking by 62% compared with that of the conventional anti-lock braking system. This improvement potentially allows more accurate control of the wheel forces during extreme manoeuvres, providing scope for the future development of advanced stability control systems.

A Survey of Traction Control and Antilock Braking Systems of Full Electric Vehicles With Individually Controlled Electric Motors

Wheel slip control for ground vehicles with individually controlled electric motors can be realized with strategies that can significantly differ from the conventional antilock braking system (ABS) and traction control (TC) system. This paper provides a review of state-of-the-art technology and recent developments in TC and ABSs using the actuation of electric motors. Particular attention is paid to the realization of slip estimators, the formalization of torque demand, and the control methods applied for the implementation of TC and ABSs. The performed analysis allowed for the differentiation of several most elaborated methods for slip and torque control and defining still imperfectly investigated problems to be covered by the further development of TC and ABSs for full electric vehicles.

Optimised design for magnetorheological brake using DOE methods

Nowadays, the automobile systems like suspension, transmission, braking and clutch systems are controlled through the wire concept. To overcome the drawbacks of the existing conventional hydraulic braking system (CHB), magnetorheological brake (MRB) is introduced in this project. CHB require complex mechanical parts to dissipate energy. A magnetorheological fluid (MRF) brake is more efficient than conventional braking system in terms of weight reduction and response time. The research work is concerned with the development of a new braking system which employs MRF as working medium. MRB design proposed in earlier studies is to be further improved according to additional practical design criteria and constraints and more in-depth electromagnetic finite element analysis. The design procedure comprises the selection of materials for MRB, creating an analytical model for finding the braking torque produced by the MRB and finite element analysis of the MRB.

A novel method for the design of regenerative brake system in an urban automotive

Environmental problems a nd fossil fuel limitations have made the automobile manufactures use renewable energies and energy recovery systems; therefore, particular attention has been paid to hybrid vehicles and/or biofuel vehicles. In this paper, the main objective is to study the appropriate strategy for choosing a better alternative to fossil fuels. Here, one of the strategies is using some devices in order to reduce the waste energies and the other is providing the condition in order to reuse the energies. For this purpose, the regenerative braking system could be mentioned as an energy recovery mechanism which slows a vehicle down by converting its energy into another form, which can be either used immediately or stored until needed. In this work, the design of regenerative braking system in hybrid vehicles has been considered and conducting a few tests, based on ISO 6469 standards; recycled energy at different speeds has been investigated. Also comparison of brake distance of this vehicle in two conditions, with and without regenerative braking has been made. The results show that this system is suitable in high speeds, but in low speeds conventional braking system has better efficiency.

Modeling and Simulation of Electro-Hydraulic Compound Regenerative Braking Control Strategy for Electric Vehicle

This paper mainly discusses the dynamic distribution of regenerative braking system and conventional friction braking system of EV.In order to meet the requirements of vehicle braking stability and recycle the braking energy whenever possible, the paper proposes a control strategy which based on ECE regulation and I curve.Then the proposed control strategy is embedded into the simulation software ADVISOR.The result shows that the control strategy of regenerative braking the paper presented is better than ADVISOR’s own on braking energy recovery, and is especially suitable for frequent braking city conditions.

Design and Analysis of Magneto-Rheological Fluid Brake (MRB)

Magneto-rheological fluids are smart fluids displaying flow properties that can be adjusted by the introduction of magnetic fields. Conventional brakes require complex mechanical parts to dissipate energy, they are having more weight, produce less braking torque and the time of response is about 300-500 milliseconds and hence brake distance is high. A Magneto-rheological fluid brake is more efficient than conventional braking system in terms of the weight reduction, and response time. In this paper an improved MRB design is made, taking into account the temperature effects and more accurate description of the material properties as well. The proposed work is concerned with the development of a new Brake-by-wire system which employs MRF as working medium. The design procedure comprises the selection of materials for MRB, creating an analytical model for finding the braking torque produced by the MRB and Finite Element Analysis of the MRB. Finite element models are built to provide a means to analyze the performance of the magneto-rheological brake system. The formulation of these models (including the definition of the geometry, material properties, boundary conditions and meshing process, as well as necessary assumptions) are described. The results obtained with the finite element models are presented and analyzed using SolidWorks 2013® and COMSOL Multiphysics 4.3b®.

Preparation of MR Fluid and Modeling of Magneto Rheological Fluid Brake (MRB)

Magneto-rheological fluids are smart fluids displaying flow properties that can be adjusted by the introduction of magnetic fields. Conventional brakes require complex mechanical parts to dissipate energy, they are having more weight, produce less braking torque and the time of response is about 300-500 milliseconds and hence brake distance is high. A Magneto-rheological fluid brake is efficient than conventional braking system in terms of the weight reduction, and response time. In this paper MR fluid is prepard and an improved MRB design is made, taking into account the temperature effects and more accurate description of the material properties as well. The proposed work is concerned with the development of a new Brake-by-wire system which employs MRF as working medium. The design procedure comprises the selection of materials for MRB, creating an analytical model for finding the braking torque produced by the MRB and Finite Element Analysis of the MRB.

Investigation on Eddy Current Braking Systems – A Review

The changing magnetic field will induce eddy currents in the conductor. These currents will dissipate energy in the conductor and generate drag force. It is found that Aluminium is the best material as conductor compared to Copper and Zinc. Also, it is found that the larger thickness of disc, more number of turns of electromagnet and higher electrical conductivity of conductor influences the generation of greater braking torque. Conventional braking system relies on adhesion force between rail and wheel. It is found that a brake built up from permanent magnet pieces that combine both magnetic rail brake and eddy current brake permits the most profitable braking action through the whole range of acceptable speeds. Permanent magnet eddy current brake uses Neodymium - Iron - Boron (NdFeB) magnets. The analysis of permanent magnet eddy current shows that the parallel magnetised eddy current topology has the superior braking torque capability. In electrically controlled eddy current braking system subjected to time varying fields in different wave forms, the triangular wave field application resulted in highest braking torque. Electromagnetic brakes were found to interfere with the signalling and train control system. Permanent magnet eddy current brakes are a simple and reliable alternative to mechanical or electromagnetic brakes in transportation applications. Greater the speed greater is the eddy current braking efficiency. Hence, author intends to work on the development and investigation of permanent magnet eddy current braking system.

Optimization of nonlinear control strategy for anti-lock braking system with improvement of vehicle directional stability on split-μ roads

In a hard braking on a split-μ road, the achievement of shorter stopping distance while maintaining the vehicle in the straight line are of great importance. In this paper, to achieve these conflicting aims, an optimal nonlinear algorithm based on the prediction of vehicle responses is presented to distribute the wheel braking forces properly. The base of this algorithm is reducing the maximum achievable braking forces of one side wheels, as low as possible, so that the minimum stabilizing yaw moment is produced. The optimal property of the proposed control method makes it possible to get a trade-off between the shorter stopping distance and the less deviation of the vehicle heading from the straight line. The special case of this algorithm leads to the conventional anti-lock braking system (ABS) which generates the maximum braking forces for all wheels to attain the minimum stopping distance. However, the ABS cannot control the vehicle directional stability directly. The simulation results carried out using a nonlinear 8-DOF vehicle model demonstrate that the designed control system has a suitable performance to attain the desired purposes compared with the convectional ABS.

Coordinate Control of Electro-Hydraulic Hybrid Brake of Electric Vehicles Based on Carsim

Motor of electric vehicle is able to be used to brake regeneratively, so braking energy can be recycled. Braking stability of electric vehicles with electro-hydraulic hybrid braking system can be influenced by braking force distribution between hydraulic braking force and regenerative braking force. In order to research on braking stability and braking energy recovery, simulation platform of electro-hydraulic hybrid brake system based on Carsim and Matlab/Simulink is built, and a control strategy of electro-hydraulic hybrid brake were proposed. The vehicle simulation models with electro-hydraulic hybrid brake system and with conventional hydraulic braking system were applied the brake on different adhesion coefficient separately. The simulation results show when electric vehicle is in the conditions of low braking intensity, all vehicle braking force is provided by regenerative braking force, and braking energy can be not only recycled, but brake performance requirement can also be satisfied; when electric vehicle is in the conditions of moderate braking intensity, regenerative braking and hydraulic braking are coordinated with each other, electro-hydraulic hybrid brake can not only satisfy the same and better brake performance, but also braking energy can be recycled and demand of hydraulic pressure can be reduced.

Eddy current braking experiment using brake disc from aluminium series of A16061 and A17075

The electromagnetic braking using eddy current was studied, focused on two series of aluminium as the brake disc which are A16061 and A17075. This paper presents the comparison for both series in a few varied parameters related to eddy current braking such as air-gap, number of turns and brake disc thickness. Optical tachometer has been used along with PULSE analyzer to capture the speed (rpm) and time (s). The findings shows that the smaller the air-gap, the larger of electromagnet turns and the thicker disc thickness is, will generate higher braking torque to stop the rotational motion of disc brake and give great performance for eddy current braking. Thos parameters that been evaluated also addressed a potential on expanding this knowledge to develop an electromagnetic braking system to replace the conventional braking system.

Design and control of variable braking force system on a two wheeler

In this work, a variable braking force system is designed and applied to a motorcycle rear wheel to control maximum braking force. The centre of gravity of the motorcycle is measured. Subsequently, an optimum disc radius is found out based on pillion load and motorcycle geometry. A load cell which is used to measure the pillion load sends a signal to a controller to activate the stepper motor for varying the position of calliper thereby effective disc radius is changed. An experiment reveals that the stopping distance of the motor cycle gets reduced if it is compared with conventional braking system.

Study of Acceleration Slip Regulation Strategy for Four Wheel Drive Hybrid Electric Car

The use of multiple power sources not only increases the modulation means of driving wheel torque,but also brings a new challenge to the acceleration slip regulation(ASR) realized by relying on conventional anti-lock braking system(ABS).Aiming at four wheel drive hybrid electric car,a powertrain forward simulation model is built with consideration of the nonlinear seven degree-of-freedom vehicle longitudinal dynamics.Using the electric motor characterized by the accurate control and rapid response of torque to adjust the torque of slipping wheel,and based on the existing energy management strategy validated in the real vehicle,ASR control algorithms of logic threshold and P-Fuzzy-PI having the qualities of multi-mode and time-sharing are respectively developed,offline simulation is conducted under the two running cases of pure electric launching and hybrid propulsion emergence acceleration at the low adhesion coefficient road.Afterwards,front wheel speed sensor signals are acquired by the hybrid control unit(HCU)and ASR is integrated into HCU,real vehicle anti-slip test is performed on the snow/ice road.Simulation and test results indicate that the proposed two kinds of anti-slip strategies can effectively prohibit the driven wheel from transient slipping,so the scheme that ASR strategy can be integrated into the energy management strategy and be carried out in the HCU is feasible and effective.

Iterative Learning Control of Antilock Braking of Electric and Hybrid Vehicles

Hybrid electric vehicles (HEVs) use multiple sources of power for propulsion which provides great ease and flexibility to achieve advanced controllability and additional driving performance. In this paper, the electric motor in HEV and electric vehicle (EV) propulsion systems is used to achieve antilock braking performance without a conventional antilock braking system (ABS). The paper illustrates that the antilock braking of HEV can be easily achieved using iterative learning control for various road conditions. A vehicle model, a slip ratio model, and a vehicle speed observer were developed to control the antilock performance of HEV during braking. Through iterative learning process, the motor torque is optimized to keep the tire slip ratio corresponding to the peak traction coefficient during braking. Simulations were performed on a compact size vehicle to validate the proposed control method. The control algorithm proposed in this paper may also be used for the ABS control of conventional vehicles.