Hydraulic Braking System Research Articles

Megawatt Wind Turbine Hydraulic Brake System Locking Device Modeling and Research Based on AMESim

As a megawatt-class wind turbine braking system, in addition to brake, it should also be in place with a wind wheel locking device to ensure that the failure of the braking system in the normal case fan will not burst start again.To solve the problem the article has designed a hydraulic locking device, and USES the AMESim software on the research and analysis.

A robust wheel slip ratio control design combining hydraulic and regenerative braking systems for in-wheel-motors-driven electric Vehicles

This paper develops a robust wheel slip controller for in-wheel-motors-driven electric vehicles equipped with both hydraulic anti-lock braking systems (ABS) and regenerative braking (RB) systems. Based on a combination of optimal predictive control design and Lyapunov theory, the issue of uncertain vehicle parameters is well addressed. A novel braking torque distribution strategy is also introduced to achieve smooth regulation of the hydraulic pressure, such that pedal pulsating effect of the traditional ABS system can be relieved. By utilizing the larger working range of the hydraulic braking (HB) system and the faster response of the RB system, a better wheel slip control performance can be obtained. Moreover, the torque distributer helps to reach a good compromise between braking distance and the magnitude of the RB torque, which is directly related to the amount of regenerated energy. The effectiveness of the proposed control system has been validated in various simulations.

Algorithms for Recuperation and Traction in Electric Vehicles

Depending on the design of the braking system foundation, a hydraulic state-of-the-art braking system in conventionally driven passenger cars distributes braking forces between front and rear axle at a ratio of about 70:30 (installed brake force distribution) [2], ❶. In hybrid and electric vehicles the brake energy can be partially recuperated. The distribution of axle specific recuperated brake energy depends on the drivetrain topology. In case of electric braking on the front axle only, a strong understeering of the vehicle would occur. When braking electrically on the rear axle only, an oversteering or even instable brake force distribution is likely. In general, this can lead to more frequent interventions of ABS/ESP. ❶ The installed brake force distribution is defined by the design of the hydraulic brake and by the wheel radius, the ideal brake force distribution results from the pitching of the vehicle [1]; the ratio of the brake force on the rear axle to the vehicle weight Fb,RA/G over the ratio of the brake force on the front axle to the vehicle weight Fb,FA/G [2] is depicted For electric vehicles with one electric motor per axle, every possible brake force distribution can be established as long as the maximum recuperation potential is not exceeded. Additional consideration of the hydraulic braking system can reduce the frequency of ABS/ESP interventions thus achieving a better balanced performance near the installed brake force distribution. Based on the brake pedal application a vehicle related target brake force Fb,Veh can be derived. For the generation of brake force four actors are available: one generator and the hydraulic brake per axle. The target brake force needs to be distributed to the four actors meeting suitable and prioritised rules: : vehicle stability : realisation of target brake force : maximum recuperation efficiency : realisation of demanded brake force distribution. The vehicle stability criterion results from axle individual acting of the generator brakes and their responsiveness, in contrast to the wheel individual ABS control of a hydraulic brake. In the following, a situation dependent reduction of the recuperation potential on one or both axles is assumed. This can be realised by a suitable pre-processing algorithm. The criterion of building up a target brake force is given by Eq. 1: The maximum recuperation efficiency demands for a preferably electric braking. Next to the stability restrictions here the degrees of freedom of the hydraulic brake are to be considered. Under consideration of the remaining recuperation potential of both electric motors and of the restrictions coming from the hydraulic braking system, the installed brake force distribution given by Eq. 2 and Eq. 3 can be established: Cp,FA, Cp,RA: brake force coeffi cient on front (FA) and rear axle (RA) τrwhl,FA, τrwhl,RA: wheel radius on front (FA) and rear axle (RA) The hydraulic brake force is separated in an unavoidable part Fb,HydBase and a freely adjustable part Fb,HydAdd. Hereby, the brake force of each axle is given by Eq. 4 and Eq. 5.

Experiment for a Parallel Hydraulic Hybrid Terminal Tractor

Hydraulic hybrid technology of vehicle has the potential to significantly improve fuel economy and reduce emission, and increasingly aroused the attention of the research institutions and automotive manufacturers all over the world. The main of this work is to design a parallel hydraulic hybrid system for a heavy terminal tractor. Firstly, overall scheme design, construction design, and hydraulic regenerative braking system (HRBS) for terminal tractor are designed. Furthermore, the hydraulic hybrid terminal tractor is refitted successfully. The test results show that the sample vehicle is credible and in good operation, a fuel economy improvement of the new scheme is 38.1%~61.6% more than conventional baseline. Experimental study has very important value in the hydraulic hybrid terminal tractor real application.

Research on Hydraulic Response Characteristics of Inlet Valve Used in Hydraulic Braking System

Hydraulic modulator regulates the pressure of four wheels independently to realize the Anti-lock Braking System (ABS) and the Electronic Stability Control (ESC) function. The pressure regulator, also called hydraulic control unit, works by controlling several valves to realize the on-off operation of the liquid paths. This paper focuses on working mechanism and hydraulic response characteristics of inlet valve of hydraulic control unit through simulation analysis.

Analysis of Influence Factors on Braking Energy Recovery of Pure Electric Vehicle

Based on the analysis the theoretical of regenerative braking and energy flow of the pure electric vehicle, the main influence factors of braking energy recovery were obtained. Ignoring the energy loss and the efficiency of system components as well as the response delay of the hydraulic braking system, two different regenerative braking control strategies were established without regard to the braking force distribution restrictions of the relevant brake laws. The simulation model was built on MATLAB/Simulink platform to analysis the effect of control strategies, vehicle mass and driving cycle for pure electric vehicle braking energy recovery. It was guidance for the development of pure electric vehicle braking energy recovery control strategy.

Design and Establishment of HIL Testing Bench for Electromagnetic and Hydraulic Hybrid Brake System

This paper discussed the brake performance and reviewed the research progress of the eddy current-hydraulic hybrid brake system. The paper mainly described the design principle of HIL testing bench, and presented a structure drawing of HIL testing bench. Based on the basic principle and structure of HIL testing bench, a real testing bench including hardware, software, interface, and virtual controller on PCs etc., is manufactured. Through two kinds of experiments on wet and dry road, the results indicates that the hybrid brake system has a perfect performance, the HIL testing bench of hybrid brake system is very convenient to study and simulate the braking system. Because the simulation on PCs cannot solve lots of actual problems, with the HIL testing bench, more actual research project can be done in the future.

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.

Study on a linear relationship between limited pressure difference and coil current of on/off valve and its influential factors

On/off solenoid valves with PWM control are widely used in all types of vehicle electro-hydraulic control systems respecting to their desirable properties of reliable, low cost and fast acting. However, it can hardly achieve a linear hydraulic modulation by using on/off valves mainly due to the nonlinear behaviors of valve dynamics and fluid, which affects the control accuracy significantly. In this paper, a linear relationship between limited pressure difference and coil current of an on/off valve in its critical closed state is proposed and illustrated, which has a great potential to be applied to improve hydraulic control performance. The hydraulic braking system of case study is modeled. The linear correspondence between limited pressure difference and coil current of the inlet valve is simulated and further verified experimentally. Based on validated simulation models, the impacts of key parameters are researched. The limited pressure difference affected by environmental temperatures is experimentally studied, and the amended linear relation is given according to the test data.

Antiskid Braking Control with On/Off Valves for Aircraft Applications

Traditional pressure servo valves used in hydraulic aircraft antiskid braking system are sensitive to contamination and require a high maintenance cost. This paper proposes an on/off-valve-based antiskid braking system with simple structure and high resistance to contamination for aircraft applications. It can improve the system reliability and reduce maintenance cost. An aircraft longitudinal motion model and a hydraulic antiskid braking system model with on/off valves are formulated. Based on these models, a switched controller with delay compensation is developed for an aircraft antiskid braking system using on/off valves. It features a switching surface derived through backstepping to govern the switching action of the valves and a pressure predictor to compensate the delay caused by response time of valves and brake lines. In addition, an approximation brake line model and a tire friction force observer are included in the controller to estimate the brake pressure and friction force, respectively. The system stability is analyzed with Lyapunov theory and Filippov framework. At last, hardware-in-loop tests are conducted on a research prototype of the hydraulic brake system and a computer-based simulator embedded with aircraft motion models. Experimental results show that the proposed on/off-valve-based aircraft antiskid braking system presents a smooth braking performance, and it is robust to uncertain road conditions.

Research on Dynamic Characteristic of Charging Valve of the Full Hydraulic Braking System

This paper introduce the working principle of accumulator charging valve. According to the static analysis of principle and structure of the valve, the model of accumulator charging valve was established by AMESim. which simulated the charging pressure and other charging characteristics. According to the result of the simulation, some technical advices for improving the performance of the full hydraulic system are provided. Thecomparison between simulation and experiment proved that the model of the valve was accurate and reliable. The performance of the charging valve meets the request of the full hydraulic braking system exactly.

The Application of Boolean Algebra in Modelling of Leakage Condition of a Car Hydraulic Braking System

A general characteristics of a car hydraulic braking system (CHBS) is presented in this publication. A graphical model of properties-component objects is developed for the above-mentioned system. Moreover, four mathematical models in terms of logic, the set theory and the Boolean algebra of Boolean functions are developed. The examination is ended with a general model of the CHBS for n - Boolean variables and the construction and mathematical-technical interpretation of this model is presented.

Simulation of the Integrated ABS and DYC Control for 4WID Electric Vehicle with Regenerative Braking

Study the lateral stability control method with regenerative braking for 4WID electrical vehicle whiling braking, an integrated control strategy with primary objective to enhance vehicle lateral stability was proposed, by which the regenerative braking, hydraulic braking, ABS and direct yaw moment control system were coordinated effectively. Simulation results on split-μ road indicated that compared with traditional ABS, the integrated control method can improve the lateral stability of vehicle at urgent braking condition, and increase the mileage of electric vehicles.

Design of Hybrid Electric Bus on Regenerative Braking System

In order to improve efficiency of Electro-Hydraulic regenerative braking system on electric bus, this paper will analysis dynamic performance and typical driving condition of electric bus based on ADAMS to establish electric bus simulation model and AMEsim to built hydraulic regenerative braking system simulation model. After simulation, displacement of Pump, volume and working pressure of accumulator, ratio of driving coupler will be optimized. The acceleration performance of electric bus will be enhanced obviously after applying hydraulic regenerative braking system.

Modelling of hydraulic regenerative braking systems for heavy vehicles

A hydraulic regenerative braking system for an articulated heavy vehicle is modelled for an idealised urban driving cycle, consisting of one stop and start from 30 mile/h, in a distance of 700 m. This model is used to guide specification of a hardware system but not to investigate brake blending methods or the torque distribution during braking. The specified system consists of a high-pressure accumulator and a low-pressure accumulator, connected by two fixed-displacement in-wheel pump–motors. One of these systems is fitted to each of the three trailer axles. This system can produce a fuel consumption saving of 21.7% over an idealised stop–start cycle. The same system was simulated over the Heavy Heavy-Duty Diesel Truck transient mode, New York City and Urban Driving Dynamometer Schedule legislative driving cycles, reducing fuel consumption by 11.2%, 17% and 11.7% respectively. Fuel consumption can be further reduced for all these cycles if engine stop–start technology is used. The potential to use the system when traversing hilly terrain was investigated, and the system was found to reduce fuel consumption by 12.6% over a V-shaped valley and by up to 5.3% over a realistic elevation profile.

Hardware-in-the-loop of Simulation for a Hydraulic Antilock Brake System

Hardware-In-the-Loop (HIL) of simulation policy is used as a rapid and economical tool for developing automotive systems effectively and for dangerous situations tests such as extreme road conditions or high travelling speeds. A method for building a HIL of simulation a hydraulic Antilock Braking System (ABS) based on MATLAB/Simulink is presented in this paper. The system is implemented for research purposes as well as for the application in educational process. It can help the user heightening the efficiency when developing the electronic device. Also, the system can be used as teaching demo software. Experiment tests of HIL scheme were carried to ensure the feasibility and effectiveness of the system.

On Hydraulic Brake System Using Bench Experiments for Off-Road Vehicles

The full power hydraulic brake system has several advantages over traditional brake actuation systems. These systems are capable of supplying fluid to a range of very small and large volume service brakes with actuation that is faster than air/hydraulic brake systems. Implementation of full power hydraulic brake system in off-road vehicles calls for good understanding of its dynamic characteristics. In this paper, we consider the problem of dynamic modeling of the brake system and develop a dynamic model for a hydraulic brake valve. First, the dynamic characteristics of full power hydraulic brake system are analyzed theoretically. The effects of varying design parameters (brake valve, accumulator and so on) and the different operating conditions are then analyzed. Second, we investigate the dynamic characteristics of a full power hydraulic brake system using a test bench, which is a loader brake system specifically designed for one construction Machinery Company. Finally, based on the experimental results, the mathematical models are amended and verified. The result shows that the model-calculated data agree well with tested data. The dynamic behavior of hydraulic valve can be well predicted with the model. The simplified models can be applied to the studies of full power hydraulic brake system dynamics.

Interaction of Anti-lock Braking Systems with Tire Torsional Dynamics

ABSTRACT A tire's torsional dynamics couple the responses of wheel/hub inertia to that of the ring/belt inertia. Depending on the effective stiffness, damping, and mass distribution of the tire, the ensuing deflections between the wheel and the ring can cause significant errors in the estimation of the tire's longitudinal slip from wheel speed measurements. However, this remains the established approach for constructing anti-lock braking system (ABS) control algorithms. Under aggressive braking events, the errors introduced by torsional dynamics may significantly affect the ABS algorithm and result in less than optimal braking performance. This article investigates the interaction of tire torsional dynamics and ABS control using a comprehensive system model that incorporates sidewall flexibility, transient and hysteretic tread-ground friction effects, and the dominant dynamics of a hydraulic braking system. It considers a wheel/hub acceleration-based ABS controller that mimics the working steps of a commercial ABS algorithm. Results from multiple sensitivity studies show a strong correlation of stopping distances and ABS control activity with design parameters governing tire/wheel torsional response and the filter cutoff frequency of the wheel acceleration signals used by the controller.

Study on Reliability of Hydraulic Brake System Based on Projection Pursuit Regression

The projection pursuit regression theory is applied to analysis the reliability of vehicle hydraulic brake system and build the projection pursuit regression model. This model on training sample fitting effect is good and shows extremely strong adaptability. We predict the reliability of certain type hydraulic brake system by this model which provides scientific basis for research on reliability of hydraulic brake system.

Investigation of Control Strategy for Hydraulic Auxiliary Braking of Tracked Vehicle Based on Pump Efficiency Analysis

On the basis of hydrostatic and hydraulic auxiliary braking system for tracked vehicle, the hydraulic pump efficiency was analyzed and discussed. And the model according to the performance analysis was set up, and the optimal working line in which the hydraulic pump working at the highest efficiency level was obtained. And an energy regenerative braking control strategy was proposed which can lead to the optimal matching of hydraulic coupler, hydraulic pump/motor. The computing results show that the hydraulic pump/motor can achieve efficient operation, and the energy regeneration efficiency of braking was improved obviously with the regenerative braking control strategy under the safe braking condition.