Pneumatic Braking Research Articles

Construction and verification of pressure response model for series dual-chamber brake valve in commercial vehicles

As a key component in pneumatic braking systems, the series dual-chamber brake valve has an important impact on the braking response and braking distance of commercial vehicles. According to its working mechanism, considered with the influence of brake pipeline, this paper presents a simulation model obtaining the valve’s dynamic characteristics accurately. A theoretical model for the valve integrated with throttle orifice and gas volume was developed. On this basis, simulation model for the series dual-chamber brake valve was developed and analyzed. A test bench was built, and validity of the model was verified by comparing the simulation results with the experimental ones. The results have shown that maximum value of the root mean square deviation of each pressure measurement point is 0.05 × 105 Pa and the correlation coefficient is 0.98. Owing to its effectiveness and accuracy, the response model can be applied in performance analysis, structural design and optimization for the series dual-chamber brake valve in commercial vehicles.

Analysis of a Measurement Method and Test System for Pressure Change Rates in Commercial Vehicle Brake Chambers.

The pressure change rate (PCR) of the brake chamber is the key control parameter and evaluation index in the pneumatic braking system for intelligent braking. The PCR threshold value of commercial vehicle brake chambers for braking comfort is analyzed. The PCR measurement method based on a laminar flow resistance tube is proposed, and the PCR test system is designed. The simulation model of a PCR test system for commercial vehicle brake chambers is presented. By analyzing the simulation and experimental results, it is validated that the PCR test system of commercial vehicle brake chambers has the function of measuring PCR in real time. Finally, according to the MSA (Measurement System Analysis) evaluation method, the performance of the PCR test system for commercial vehicle brake chambers is analyzed, and the correctness and applicability of the test system are verified.

Research on Measurement Principle and Key Measuring Devices of Pressure Change Rate for Electronically Controlled Pneumatic Brake of Commercial Vehicle Based on Poiseuille's Law.

For intelligence brakes in the electronic pneumatic brake system of commercial vehicles, the pressure change rate is used as the key control parameter and evaluation index. This can improve the brake safety, stability, and ride comfort of the vehicle. The real-time detection of the brake pressure change rate for commercial vehicles is the premise for realizing the accurate control of brake pressure change rate. Based on Poiseuille’s law, an efficient measurement method of brake pressure change rate is proposed for commercial vehicles, and a new measuring device with an isothermal container and laminar flow resistance tube as the core components is designed. Through thermal insulation performance tests, flow resistance tests and measurement accuracy tests, combined with simulations, the effects of structural parameters and copper wire filling density on the performance of the isothermal container are analyzed, and these key parameters are optimized to improve the thermal insulation performance. A tubular laminar flow resistance tube composed of 304 stainless steel capillaries in parallel is designed. The influence mechanism of core parameters such as the number, radius, and length of laminar flow channels on its performance is studied, and the optimal parameter array is selected to optimize its performance. The experimental platform for measuring brake pressure change rate is constructed. By comparing the measurement curve of brake pressure change rate under simulation and experiment, the correctness and effectiveness of the pressure change rate measurement principle and the key components for electronically controlled pneumatic brakes of commercial vehicles are verified to meet engineering requirements.

Integrated simulation platform for a locomotive braking system

We used a locomotive and a rail car to examine the working principle of a locomotive braking system. We established models of the locomotive braking system, the locomotive dynamics, and the brake disc thermodynamics and, based on the correlation parameters for each subsystem, built an integrated simulation platform for the locomotive braking system based on Simulink and AMESim. Using this platform, we simulated the characteristics of the pneumatic braking unit, the locomotive braking, and temperature increase in the brake disc under emergency braking conditions. We compared our simulation results with experimental data and the results showed that the integrated simulation platform for the locomotive braking system could successfully be used to study locomotive braking control on the vehicle level. We provide a design optimization method for the development of a braking system, the setting of the anti-skid criterion, and early warning of an increase in the brake disc temperature.

Research on accurate modeling and control for pneumatic electric braking system of commercial vehicle based on multi-dynamic parameters measurement

Accurate pressure control and fast dynamic response are vital to the pneumatic electric braking system (PEBS) for those commercial vehicles that require higher regulation precision of braking force on four wheels when braking force distribution is carried out under some conditions. Due to the lagging information acquisition, most feedback-based control algorithms are difficult to further improve the dynamic response of PEBS. Meanwhile, feedforward-based control algorithms like predictive control perform well in improving dynamic performance but because of the large amount of computation and complexity of this kind of control algorithm, it cannot be applied in real-time on the single-chip microcomputer, and it is still in the stage of theoretical research at present. To address this issue and for the sake of engineering reliability, this article presents a logic threshold control scheme combining analogous model predictive control (AMPC) and proportional control. In addition, an experimental device for real-time measuring PEBS multi-dynamic parameters is built. After correcting the key parameters, the precise model is determined and the influence of switching solenoid valve on its dynamic response characteristics is studied. For the control scheme, numerical and physical validation is executed to demonstrate the feasibility of the strategy and for the performance of the controller design. The experimental results show that the dynamic model of PEBS can accurately reflect its pressure characteristics. Furthermore, under different air source pressures, the designed controller can stably control the pressure output of PEBS and ensure that the error is within 0.08 bar. Compared with the traditional control algorithm, the rapidity is improved by 32.5%.

An adaptive fuzzy sliding‐mode control for regenerative braking system of electric vehicles

SummaryThis article proposes a novel fuzzy sliding‐mode control scheme under an adaptive control strategy for energy management mechanism in electric vehicles that are subject to a regenerative braking system. The effectiveness of the fuzzy logic controller is to adjust the sliding mode parameters according to the slip ratio tracking error between the optimal slip ratio and the actual slip ratio. Specifically, the proposed torque distribution strategy can integrate the best battery condition and energy recovery efficiency under the practical constraints through this control method by fixing the pneumatic braking torque and motor torque. Finally, an electric vehicle model is established in the Simulink environment to verify the applicability of the proposed control algorithm.

Train Braking Time Variations Changing the Pressurized Air Temperature

Braking time in a moving train at standard speeds has become a critical variable that increasingly concerns the industry. The present paper discusses the possible option of temperature variation to cut down the response time of the whole pneumatic braking system in a train installation. A pneumatic system, considered equivalent to the system existing in a real train, was experimentally analyzed to account for the time and characteristics of a sonic pressure wave moving in the pipes. The available system behavior was compared for two different air temperatures. The obtained results point to a relevant temperature effect on the pressure wave transmission, which may promote time or distance shortening in a standard braking process. Although in the experimental campaign only two initial temperatures could be set, the study shows a possible research path for future improvements. A parallel theoretical calculation corrected by the effect of the relevant elements in the pipes was performed to allow a comparison with the experiments.

Pressure control for pneumatic electric braking system of commercial vehicle based on model predictive control

Precise braking pressure control of a pneumatic electric braking system (PEBS) poses challenging non-linear control problems, since it can operate in several distinct discrete processes (the pressure increasing, holding and decreasing) by switching the on-off solenoid valves and the piston of relay valve moves irregularly. This article describes the development and experimental validation of a viable controller for an electronically controlled braking pressure based on the theory of model predictive control (MPC). The controller design consists of two parts. The non-linear characteristic is first studied to ensure the pressure response of PEBS when the opening time is 4–10 ms in a fixed period, followed by calculation and prediction of the optimal on-off time of inlet valve and release valve based on the current braking pressure to realize steady state. A logic rule is designed to ensure that the MPC controller and feedback control work coordinate to guarantee engineering reliability. A comprehensive system model is derived to help characterize system non-linearities and design the MPC predictive model. Simulations and experimental results are presented finally to show how the MPC and feedback control strategy can be successfully applied to solve the braking pressure control of a PEBS in a systematic way.

Detailed Modeling of Pneumatic Braking in Long Combination Vehicles

Detailed Modeling of Pneumatic Braking in Long Combination Vehicles

Automated Pneumatic Braking and Bumper System

Automobiles have been used to move human beings or things and the automobile technology has been developed within the last few years. The traffic accidents are increasing as automobile production has been increasing. The number of casualties during the vehicle accidents is very large as compared to the other causes of death. It is important to prevent accidents and to protect the driver and pedestrian when accidents occur. Though there are different causes for these accidents but proper technology of braking system and technology to reduce the damage during accident (such as pneumatic bumper system) can be effective on the accident rates. Therefore, pre-crashing system is demanded. Automotive safety has gained an increasing amount of interest from the general public, governments, and the car industry. The pre-crash system is to prevent accidents on roads with poor visibility by using sensor network to find invisible vehicles, which are to be detected by autonomous on-vehicle sensors. The pre-crashing system is processing the sensor data and controlling the vehicle to prevent accidents and accidents caused by careless driving. The pneumatic system is simple and easy in operation and hence can be used in automation industry.

A Software-in-the-Loop Simulation of Vehicle Control Unit Algorithms for a Driverless Railway Vehicle

The realization of the first prototype of a vehicle requires several tests of the algorithms implemented on the electronic control unit (ECU). This represents an important step for conventional vehicles, which becomes fundamental when dealing with unmanned vehicles. Since there is no human supervision, most critical tasks are handled by the control unit, which results in higher complexity for the control algorithms. In this work, a software-in-the-loop (SiL) test bench is used to validate the control algorithms of a vehicle control unit (VCU) for a driverless railway vehicle (DLRV). The VCU manages the control of the traction motors, pneumatic braking systems, and range extender, as well as control of the hybrid powertrain configuration to guarantee a high level of availability via the use of redundant systems. The SiL test bench has been developed in a Simulink real-time environment, where the vehicle model is simulated along with its fundamental subsystems. The model communicates with the VCU through a CAN bus protocol in the same way that it will operate with a real vehicle. The proposed method can be used to simulate many mission profiles for the DLRV, which may last several hours each. Moreover, this kind of test bench ensures a high time resolution, which allows one to find solutions for problems which occur with a time scale that is much smaller than the simulation time scale.

Research of Determining Low-Reliability Elements of Multiple-Flows Compressed Air Braking System Based on Goal-Oriented (GO) Methodology

The multi-flows pneumatic braking system is one of the modern braking systems equipped with truck vehicles which is a very complex system consisting of many elements connected in series or parallel. The reliability of the braking system has a significant influence on safety and the ability to manoeuvre. The study of identifying low-reliability elements in the brake system is of great significance to improve the efficiency of maintenance and repair. This article shows the research results that determine low-reliability elements of the multi-flows pneumatic brake system based on GO methodology, and allow to examine each element's reliability and the complex system. The reliability assessment model is built based on GO theory and statistics data collected at the used units about the frequency of damage, ability, and time to repair and restore the assemblies in the brake system. By using this model, the reliability of the assemblies and the whole system can be determined at any point in time relative to the actual operating time of the brake system. The article's research results can be applied for surveying other components’ reliability and complex systems such as steering or suspension systems.

Study on Pressure Change Rate of the Automatic Pressure Regulating Valve in the Electronic-Controlled Pneumatic Braking System of Commercial Vehicle

In contrast to the traditional pneumatic braking system, the electronic-controlled pneumatic braking system of commercial vehicles is a new system and can remedy the defects of the conventional braking system, such as long response time and low control accuracy. Additionally, it can adapt to the needs and development of autonomous driving. As the key pressure regulating component in electronic-controlled pneumatic braking system of commercial vehicles, automatic pressure regulating valves can quickly and accurately control the braking pressure in real time through an electronic control method. By aiming at improving driving comfort on the premise of ensuring braking security, this paper took the automatic pressure regulating valve as the research object and studied the pressure change rate during the braking process. First, the characteristics of the automatic pressure regulating valve and the concept of the pressure change rate were elaborated. Then, with the volume change of automatic pressure regulating valve in consideration, the mathematical model based on gas dynamics and the association model between pressure change rate and vehicle dynamic model was established in MATLAB/Simulink and analyzed. Next, through the experimental test of a sample product, the mathematical models have been verified. Finally, the key structure parameters affecting the pressure change rate of the automatic pressure regulating valve and the influence law have been identified; therefore, appropriate design advice and theoretical support have been provided to improve driving comfort.

Electrified Vehicle Wheel Slip Control Using Responsiveness of Regenerative Braking

In vehicles, wheel locking and associated instability issues can be prevented by regulating wheel brake torque during braking. In contrast with conventional vehicles, electrified vehicles have both friction and regenerative braking. Typically, pneumatic friction braking is used for Wheel Slip Regulation (WSR) in Heavy Commercial Road Vehicles (HCRVs). However, the pneumatic brake system has a lower bandwidth compared to a regenerative brake system, thereby affecting the braking performance of the HCRV during WSR application. This article proposes an Integral Sliding Mode Control (ISMC) based WSR to exploit the responsiveness of regenerative brakes during braking. The proposed control strategy was evaluated in a hardware-in-loop experimental setup. For different operating conditions, the experimental results conveyed that the proposed braking strategy incorporating regenerative braking reduced the slip ratio tracking root mean square error and stopping distance in the range of 12.13% to 72% and 2.43% to 4% respectively compared to conventional frictional braking (without regenerative braking).

Accident Avoiding by Using Pneumatic Bumper

A control system for pneumatic bumper activation and automated braking in automobiles is designed and built. The transmitter and receiver circuit, control unit, pneumatic bumper system and pneumatic brake system are all included in this project. The obstruction is detected by the IR sensor of the camera. The bumper activation system and pneumatic braking system are activated simultaneously if there is an obstruction in the path of the vehicle. In order to produce the man and vehicle, pneumatic bumper and braking systems are employed. A few automobile manufacturers currently utilise passive dampers positioned between the bumper and the vehicle's frame as a kind of shock absorption. It is possible to waste a large amount of energy through the compression of the damper. The residual force will be transmitted to the vehicle's chassis by means of this mechanism. Static damping coefficient of this system is typically quite high, making it unable to dissipate higher speed impact forces. To decrease the crash impact and transfer of the residual force, dampers were utilised in this project to give a dynamic damping coefficient. To create a notion for an accident-avoiding system that can fulfil the requirements of safe travel, the present study is an attempt. Embedded electrical sensor and mechanical elements are used in this idea, which is a bit different from other types of machines.

ШВИДКІСНИЙ ВАНТАЖНИЙ ПОЇЗД ДЛЯ ПЕРЕВЕЗЕННЯ КОНТЕЙНЕРІВ ЗІ ШВИДКІСТЮ 200 КМ/ГОД

The article is devoted to building of freight trains for transportation of containers with railway transport at speed of 200 km/h. The article considers building experience of the high speed freight trains for transportation of containers at speed of 350 km/h. Main technical characteristics of the rolling stock, involved in freight high speed railway transportation in foreign countries are analyzed. The purpose of the article is to discover design features of the rolling stock for freight transportations at speed of 200 km/h and in modeling of the braking processes during electro pneumatic and pneumatic braking of the rolling stock from speed of 200 km/h to 160 km/h. The concept of the rolling stock for high speed freight transportation of containers is proposed. A specialized platform with bogies, disc brake and air-spring suspension Installed on it is used as a rolling stock. A brief description of the brake system is given; its main features are shown. A pneumatic scheme of the container block of the braking equipment and the general view of container block is given. Classified freight train, which consists of 30 platform cars and has two locomotives on each side is proposed for high speed transportation. Brake distance during electro pneumatic and pneumatic braking at freight train speed of 160 km/h is calculated. The results of calculated studies of the trains braking efficiency are given, which showed that at the speed of the freight train of 200 km/h, the brake distances at electro pneumatic and pneumatic braking are represented by 1472 m and 1571 m respectively, which corresponds to the technical requirements of the European Union TSI. Key words: high-speed freight trains, container, speed, brake distance, disc brakes.

Design and Development of a Pneumatic Braking Device for Testing the Gas Turbine Plant

Design and Development of a Pneumatic Braking Device for Testing the Gas Turbine Plant

Impact of a modified braking valve for static and dynamic characteristics of pneumatic braking systems of agricultural trailers

Pneumatic braking systems of agricultural trailers contain brake valves with adjustable predominance of the output pressure relative to the control pressure. The goals of our study were to improve the static and dynamic properties of agricultural trailer pneumatic braking systems by modification of brake valve construction with implementing a throttle valve to the predominance device in valve. Proposed correction device ensures that the intensity of the predominance effect depends on the rate of pressure rise in control chamber of the braking valve. Initial testing of three agricultural trailers' braking systems has confirmed the effect of modifying relay emergency valve to shortening the response time of their braking systems while maintaining a follow-up action under steady state conditions.

Multi-Objective Trajectory Optimization for Freight Trains Based on Quadratic Programming

The overspeed protection, smooth driving, punctuality, and energy efficiency of freight trains largely depend on their trajectory optimization. This paper proposes a multi-objective optimization model, which maximizes the weighted sum of energy efficiency, punctuality, and driving smoothness. Model constraints systematically cover many practical conditions, including varying line resistance, overspeed protection, discrete neutral zones, and nonlinear traction and electric braking characteristics. Electric braking and pneumatic braking are distinguished in the freight train model, and the utilization of feedback braking energy is also considered. By nonlinear approximation, the proposed multi-objective optimization model is solved by the quadratic programming (QP) algorithm, and optimized trajectories are obtained. Numerical simulation demonstrates the correctness and effectiveness of the proposed method. Comparisons with two actual trials show that the energy efficiency and driving smoothness of the proposed method are better than that of the drivers’ operation with the same journey time. In addition, the algorithm has a short computation time, which has the potential to be integrated for on-board devices such as the driver advisory system (DAS).

Delay compensated pneumatic brake controller for heavy road vehicle active safety systems

Performance enhancement of typically sluggish pneumatic brake actuators in Heavy Commercial Road Vehicles (HCRVs) is necessary for the efficacious operation of active safety systems. This study develops a robust Proportional Integral Derivative (PID) controller using the Kharitonov theorem for pneumatic brakes. To account for the inherent time delay present in pneumatic brakes, Padé approximation and state prediction methods were used. The efficacy of the brake controller when used for active safety system operation has been investigated by conducting Hardware-in-Loop (HiL) experiments. It was found that state prediction based design turned out to be a better choice for handling time delays in the brake actuator. This controller was then compared with a Sliding Mode Control (SMC) based brake controller and the performance of both controllers was comparable. Further, the state prediction based PID brake controller was found to be robust up to 100% variation in system time constant and 40% variation in time delay for different road and load conditions.