Braking Control Research Articles

Research on Automatic Braking and Traction Control of High-speed Train Based on Neural Network

With the rapid development of economy and technology, people’s quality of life has been continuously improved, which also makes people put forward higher requirements for the quality of transportation. As far as railway transportation is concerned, the running speed and route of trains in the past gradually failed to meet people’s travel needs. Automatic train operation system (ATO), under the protection of automatic train protection system, realizes automatic train driving according to the instructions of automatic train supervision system, and can automatically control the starting, traction, cruising, idling and braking of trains. Traction drive system is the core part of high-speed train, and traction drive converter technology is one of the key technologies of high-speed train. In this paper, according to the different working mechanism of traction and braking, the dynamic model of train under traction and resistance braking is established by combining neural network algorithm, and the corresponding controller is designed by using nonlinear backstepping design method to realize automatic tracking of train speed and position.

Regenerative braking control under sliding braking condition of electric vehicles with switched reluctance motor drive system

To enhance braking energy recovery and improve braking comfort under sliding braking condition for electric vehicles (EVs) with switched reluctance motor (SRM), a novel regenerative braking control scheme based on braking force optimization controller and angle optimization controller is presented in this paper. Firstly, the current regulation method is developed, and the braking torque control strategy with four-phase currents and voltages of SRM drive system is proposed. Braking system (BS) of EVs including mechanical braking system and regenerative braking system is established. Then, the multi-objective optimization strategy (MOOS) for vital control parameters of regenerative braking system is proposed to improve regeneration braking comprehensive performance under sliding braking condition of EVs, where braking energy recovery efficiency, braking impact, and current fluctuation are considered as indexes to reflect working distance, braking smoothness, and battery lifetime of EVs, respectively. Furthermore, braking force optimization controller and angle optimization controller are developed by means of the multi-objective optimization results. Finally, compared to the efficiency optimization, the braking comfort optimization, and the current smoothness optimization strategy, the regenerative braking control scheme with MOOS can effectively increase working distance, improve braking smoothness, and extend battery lifetime of EVs under sliding braking condition. Furthermore, the real-time performance and effectiveness of the braking torque control strategy proposed are verified by simulation and PIL test.

Simulation Research on Regenerative Braking Control Strategy of Hybrid Electric Vehicle

This paper proposes a double layered multi parameters braking energy recovery control strategy for Hybrid Electric Vehicle, which can combine the mechanical brake system with the motor brake system in the braking process to achieve higher energy utilization efficiency and at the same time ensure that the vehicle has sufficient braking performance and safety performance. The first layer of the control strategy proposed in this paper aims to improve the braking force distribution coefficient of the front axle. On the basis of following the principle of braking force distribution, the braking force of the front axle and the rear axle is reasonably distributed according to the braking strength. The second layer is to obtain the proportional coefficient of regenerative braking, considering the influence of vehicle speed, braking strength, and power battery state of charge (SOC) on the front axle mechanical braking force and motor braking force distribution, and a three-input single-output fuzzy controller is designed to realize the coordinated control of mechanical braking force and motor braking force of the front axle. Finally, the AMESim and Matlab/Simulink co-simulation model was built; the braking energy recovery control strategy proposed in this paper was simulated and analyzed based on standard cycle conditions (the NEDC and WLTC), and the simulation results were compared with regenerative braking control strategies A and B. The research results show that the braking energy recovery rate of the proposed control strategy is respectively 2.42%, 18.08% and 2.56%, 16.91% higher than that of the control strategies A and B, which significantly improves the energy recovery efficiency of the vehicle.

A novel state energy spatialization regenerative braking control strategy based on Q- learning algorithm for a super-mild hybrid electric vehicle

ABSTRACT Most of the existing regenerative braking control strategies maintain the battery balance by the state of charge (SOC) penalty function. However, the SOC penalty function only realizes the instantaneous balance and ignores the global balance. To solve this problem, this paper proposes a novel state energy spatialization regenerative braking control strategy. Firstly, the battery energy is converted from the time domain to the space domain at each state. Based on the principle of balance between driving energy consumption and braking recovery energy, the mathematical model of referenced recovery energy is established. Then, considering the maximum energy recovery and the global battery energy balance, the return function is formulated, which takes the referenced recovery energy as the constraint condition. Subsequently, the proposed strategy is optimized by Q-learning algorithm and the optimal motor torques of regenerative braking are obtained. Finally, the Kullback–Leibler (KL) divergence rate is adopted to recognize the type of actual driving cycle, and the online optimal motor torque is obtained by looking up the corresponding table. Using the MATLAB/Simulink software, the simulation model of real working condition in Yubei district of Chongqing is established. The simulation results show that the SOC variation of the proposed strategy is 33.5% and 20.1% lower than that of the maximum energy recovery and DP strategy, respectively. The results indicate the proposed strategy maintains the global balance of battery energy better than the conventional strategy.

Testing and Analysis of Lane Departure Warning and Lane Keeping Assist System Response

<div class="section abstract"><div class="htmlview paragraph">Many new vehicles come equipped with Advanced Driver Assistance Systems (ADAS) as standard or optional features. These technology packages frequently include Lane Departure Warning (LDW), an electronic system designed to alert the driver when the vehicle begins to depart from its lane. These systems identify lane boundaries using computer analysis of video captured by a forward-facing camera, typically mounted near the rear-view mirror. Some vehicles are also equipped with Lane Keeping Assist (LKA). Upon detecting an unintended lane departure, LKA will make electronic steering and/or braking control inputs to keep the vehicle in its original travel lane. Four vehicles equipped with LDW and LKA were tested: a 2019 Toyota Corolla, 2019 Honda Civic, 2020 Ford Explorer, and 2019 Chevrolet Tahoe. Tests were conducted on a straight, flat road with clear lane markings. Lane departures to the left and to the right were initiated by the test driver at 45 and 65 mph. Using a VBOX 3i RTK DGPS, data related to the vehicle’s speed, acceleration, and driver- and software-related control inputs were collected via the vehicle’s CAN bus. Additionally, the VBOX collected vehicle location data of ±2 cm (±0.79 in) accuracy relative to survey points. Analysis of test data yielded details of system-level behaviors. For LDW, the average warning issue point (lateral distance prior to reaching the lane boundary) observed was 1.33 ft, the average rate of departure (lateral velocity) was 1.45 ft/s, and the warning occurred 0.76 sec before lane departure. Lane keeping actions began, on average, 1.13 ft from the lane boundary (0.66 sec before lane departure) and involved 4.81 degrees of steering with an average maximum lateral acceleration of 2.86 ft/s<sup>2</sup> (0.09 g). The LKA systems tested permitted the vehicles’ outside tires to exceed the lane boundaries by an average of 0.14 ft.</div></div>

Regenerative Braking Control Strategy of Electric Vehicles Based on Braking Stability Requirements

Electric vehicles are effective way to solve energy and environmental problems, but the promotion and application of electric vehicles are suppressed by their limited endurance range seriously. The regenerative braking technology is an important method to increase the endurance range of the electric vehicle. During the braking process, the kinetic energy of the electric vehicle can be converted into electric energy and stored in the energy source device with the regenerative braking system, so the endurance range of the electric vehicle can be increased accordingly. In order to increase the efficiency of energy recovery, a regenerative braking strategy with the optimization distribution algorithm is proposed in this paper, and the braking forces of the front and rear axles are distributed optimally with variable ratios based on the braking strength. With the optimal braking force distribution ratio and related constraint conditions, the regenerative braking control strategy was designed to meet the braking stability and the maximum braking energy recovery. And then a simulation model of the braking control strategy was built with MATLAB/Simulink software, and the simulation tests on UDDS and NEDC cycle conditions were done to verify the effectiveness of the designed regenerative braking control strategy. Compared with the control strategy of ADVISOR software, the braking energy recovery efficiency was improved more than 51.9 % while maintaining the braking stability.

On pre-emptive vehicle stability control

Future vehicle localisation technologies enable major enhancements of vehicle dynamics control. This study proposes a novel vehicle stability control paradigm, based on pre-emptive control that considers the curvature profile of the expected path ahead in the computation of the reference direct yaw moment and braking control action. The additional information allows pre-emptive trail braking control, which slows down the vehicle if the predicted speed profile based on the current torque demand is deemed incompatible with the reference trajectory ahead. Nonlinear model predictive control is used to implement the approach, in which also the steering angle and reference yaw rate provided to the internal model are varied along the prediction horizon, to account for the expected vehicle path. Two pre-emptive stability control configurations with different levels of complexity are proposed and compared with the passive vehicle, and two state-of-the-art nonlinear model predictive stability controllers, one with and one without non-pre-emptive trail braking control. The performance is assessed along obstacle avoidance tests, simulated with a high-fidelity model of an electric vehicle with in-wheel motors. Results show that the pre-emptive controllers achieve higher maximum entry speeds – up to ∼34% and ∼60% in high and low tyre-road friction conditions – than the formulations without preview.

A predictive control method to improve pressure tracking precision and reduce valve switching for pneumatic brake systems

Pneumatic brake systems are crucial for the operation of trains. However, due to switching characteristics of on/off solenoid valves, the precise pressure control and low switching activities of valves are difficult to guarantee simultaneously during braking. To address the issue, a hybrid model predictive control (MPC) method is proposed for implementing the multi-objective optimisation in this paper, i.e. the precise pressure tracking and the valve switching reduction. In order to model the hybrid behaviour caused by continuous dynamics of the pressure and discrete features of solenoid valves, the mixed logic dynamical system theory is applied. Then, the braking control problem is recast as a hybrid MPC problem, which jointly optimises the pressure tracking precision and the valve switching. A mixed integer linear program is formulated to solve the MPC problem in an efficient way. Both simulation and experiment results show that the accurate pressure control and low switching activities of valves can be achieved by the proposed method when compared with existing methods.

Integrated Braking Control for Electric Vehicles with In-Wheel Propulsion and Fully Decoupled Brake-by-Wire System

This paper introduces a case study on the potential of new mechatronic chassis systems for battery electric vehicles, in this case a brake-by-wire (BBW) system and in-wheel propulsion on the rear axle combined with an integrated chassis control providing common safety features like anti-lock braking system (ABS), and enhanced functionalities, like torque blending. The presented controller was intended to also show the potential of continuous control strategies with regard to active safety, vehicle stability and driving comfort. Therefore, an integral sliding mode (ISM) and proportional integral (PI) control were used for wheel slip control (WSC) and benchmarked against each other and against classical used rule-based approach. The controller was realized in MatLab/Simulink and tested under real-time conditions in IPG CarMaker simulation environment for experimentally validated models of the target vehicle and its systems. The controller also contains robust observers for estimation of non-measurable vehicle states and parameters e.g., vehicle mass or road grade, which can have a significant influence on control performance and vehicle safety.

Shortening the Braking Distance of a Passenger Car through Coordinated Control of Brakes and Active Suspension

Aktif süspansiyon – fren entegre kontrolü, akademik ve otomotiv sanayi literatüründe popüler bir araştırma konusudur. Bu araştırma alanına odaklanan bu çalışma, iki entegre kontrol alternatifi önermektedir. İlk metot, aracın arka süspansiyonuna yerleştirilecek doğrusal elektrik motorları gözetilerek tasarlanmıştır. Bu metotta, aracın frenleme performansını ve sürüş konforunu geliştirecek olan kontrol sinyalleri, teker kayması, ve arka doğrusal elektrik motor kuvvetlerine bölüştürülmektedir. İkinci metot ise, hem ön, hem de arka süspansiyonlara yerleştirilecek doğrusal elektrik motorları gözetilerek tasarlanmıştır. Bu kez kontrol hedefi, teker kuvveti – teker kayması karakteristik grafiğinin pik noktasında kalmaktır. Aynı zamanda aracın yunuslama hareketi de kısıtlanmaktadır. Her iki kontrol yaklaşımı, kontrol bölüştürme yöntemini uygulamaktadır. Çalışmada özetlenen simülasyon çalışmaları ile, önerilen kontrolcülerin, pasif süspansiyonlu konvansiyonel araç ile kıyaslandığında aracın frenleme mesafesini kısaltacağı gösterilmiştir.

Hierarchical cooperative control of anti-lock braking and energy regeneration for electromechanical brake-by-wire system

Energy regeneration during braking process is the key energy-saving technology for electric vehicles (EVs). However, when the anti-lock braking system (ABS) is triggered, it is difficult to coordinate the mechanical braking and regenerative braking to ensure the vehicle stability and maximal energy regeneration. This study proposes a hierarchical cooperative control for the electromechanical brake-by-wire system (EBW) to solve this problem. First, a novel pneumatic EBW is designed. Then, a pneumatic pressure model is built and simplified, based on which a pressure regulation method is proposed. Next, the hierarchical cooperative control is proposed, where top layer controls slip ratio, mid layer distributes braking torque, and bottom layer controls the electric motor torque and pneumatic pressures. Finally, the experiment results show that the proposed strategy achieves better braking safety and energy regeneration performance than mature strategies in products. The research provides an effective solution of cooperative control for EVs, and it can be used as a low-cost approach in other vehicle stability control where precise braking torque is required.

A Comparative Study of Energy Consumption and Recovery of Autonomous Fuel-Cell Hydrogen–Electric Vehicles Using Different Powertrains Based on Regenerative Braking and Electronic Stability Control System

Today, with the increasing transition to electric vehicles (EVs), the design of highly energy-efficient vehicle architectures has taken precedence for many car manufacturers. To this end, the energy consumption and recovery rates of different powertrain vehicle architectures need to be investigated comprehensively. In this study, six different powertrain architectures—four independent in-wheel motors with regenerative electronic stability control (RESC) and without an RESC, one-stage gear (1G) transmission, two-stage gear (2G) transmission, continuously variable transmission (CVT) and downsized electric motor with CVT—were mathematically modeled and analyzed under real road conditions using nonlinear models of an autonomous hydrogen fuel-cell electric vehicle (HFCEV). The aims of this paper were twofold: first, to compare the energy consumption performance of powertrain architectures by analyzing the effects of the regenerative electronic stability control (RESC) system, and secondly, to investigate the usability of a downsized electrical motor for an HFCEV. For this purpose, all the numerical simulations were conducted for the well-known FTP75 and NEDC urban drive cycles. The obtained results demonstrate that the minimum energy consumption can be achieved by a 2G-based powertrain using the same motor; however, when an RESC system is used, the energy recovery/consumption rate can be increased. Moreover, the results of the article show that it is possible to use a downsized electric motor due to the CVT, and this powertrain significantly reduces the energy consumption of the HFCEV as compared to all the other systems. The results of this paper present highly significant implications for automotive manufacturers for designing and developing a cleaner electrical vehicle energy consumption and recovery system.

A review on braking control and optimization techniques for electric vehicle

In this modern world, due to limited fossil fuels, increasing cost, and environmental concerns a clean and sustainable transportation system in the form of electric vehicles (EV) is now becoming popular. On the other hand, electric vehicles have an advantage such as zero-emission, less maintenance, comfortable ride, less noise, etc. An electric vehicle is driven by an electric motor so considering driving patterns and road traffic conditions the vehicle often requires braking operation. The most common method is to employ mechanical brakes to reduce the speed of EV. However, mechanical braking mechanism results in friction which in turn, into heating losses and reduces the efficiency of EV. Therefore, regenerative braking system (RBS) and energy management system are employed in addition to mechanical braking for increasing the braking efficiency of the EV system. It is reported in many literatures about different regenerative braking control techniques for EV systems. This paper presents a review of regenerative braking and braking energy management techniques by considering different driving situations and road conditions.

Experimental study on braking and stability performance during low speed braking with ABS under critical road conditions

During braking with ABS (Anti-Lock Brake System), low braking initial speed causes to build-up and reduce brake pressure in longer time period due to extending application time of brake pressure and response time of solenoid valve. Also, the decision about speed and acceleration variations of wheel becomes very difficult due to weak speed signals arising from low speed. This results in lower braking torque than needed on the wheels. Therefore, effects of weak wheel speed signal become more pronounced in critical road conditions due to sudden changes in wheel speed. In this study, the effects of these problems occurring in low speed were investigated on both control and braking performance of ABS under critical road conditions. For this, ABS tests were carried out for low and high speeds on four different road types, which include slippery, wet and µ-jump tests (from wet to slippery and from slippery to wet). In this way, the results were compared to both vehicle speed and road type. The test results show that the low speed worsens braking stability, control and braking performance of ABS, regardless of road conditions. For this reason, it is proposed that ABS control algorithm must be divided in two parts as low and high speed control.

Experimental prototyping of the adhesion braking control system design concept for a mechatronic bogie

The dynamic parameters of a roller rig vary as the adhesion level changes. The change in dynamics parameters needs to be analysed to estimate the adhesion level. One of these parameters is noise emanating from wheel–rail interaction. Most previous wheel–rail noise analysis has been conducted to mitigate those noises. However, in this paper, the noise is analysed to estimate the adhesion condition at the wheel–rail contact interface in combination with the other methodologies applied for this purpose. The adhesion level changes with changes in operational and environmental factors. To accurately estimate the adhesion level, the influence of those factors is included in this study. The testing and verification of the methodology required an accurate test prototype of the roller rig. In general, such testing and verification involve complex experimental works required by the intricate nature of the adhesion process and the integration of the different subsystems (i.e. controller, traction, braking). To this end, a new reduced-scale roller rig is developed to study the adhesion between wheel and rail roller contact. The various stages involved in the development of such a complex mechatronics system are described in this paper. Furthermore, the proposed brake control system was validated using the test rig under various adhesion conditions. The results indicate that the proposed brake controller has achieved a shorter stopping distance as compared to the conventional brake controller, and the brake control algorithm was able to maintain the operational condition even at the abrupt changes in adhesion condition.

Electro-hydraulic Composite Emergency Braking System Based on Frequency Reconstruction Control

For four-wheel independently driven (FWID) electric vehicle (EV), in order to guarantee braking reliability, hydraulic braking system and motor anti-drag braking system are usually used at the same time. In this paper, a novel electro-hydraulic composite braking control strategy is given to solve the distribution problem of braking torque between hydraulic braking torque and motor anti-drag braking torque. The high-frequency part of the desired braking torque is distributed to the motor brake through a high-pass filter so as to fully utilize the fast response characteristics of the motor. Meanwhile, the low-frequency part of the desired braking torque is distributed to the hydraulic brake through a low-pass filter so as to reduce the load of the motor. The cost functions are designed to determine the cut-off frequency of low-pass and high-pass filters. Through the joint simulation of Matlab/Simulink and TruckSim, the braking effect of the electro-hydraulic composite braking is better than that of pure hydraulic braking with no motor to modulate the braking torque.

New Integrated Vehicle Stability Control of Active Front Steering and Electronic Stability Control Considering Tire Force Reserve Capability

To address the problem of the mutual interference and control distribution in the integrated stability control of active front steering (AFS) and electronic stability control (ESC), this study proposes a new integrated stability controller of AFS and ESC based on holistic control framework. A distribution rule of longitudinal and lateral tire force based on equal reserve capacity of tire force is designed to distribute the control right of steering and braking. A UniTire model with combined slip condition is also designed for the integrated control of steering and braking. Model predictive control (MPC) is adopted to address the constrained multi-objective control problem. To reduce the complexity of the system and improve the real-time performance of the system, a linear time-varying MPC controller is designed by linearizing the nonlinear system, and then the constrained MPC control problem is transformed into a quadratic programming problem for solving. Finally, the proposed method is validated on the basis of Matlab/Simulink and CarSim co-simulation platform. Results show that the proposed method has obvious effects on solving the mutual interference and control right distribution of steering and braking and improving vehicle stability.

Research on Control Strategy of Hydraulic Regenerative Braking of Electrohydraulic Hybrid Electric Vehicles

The vehicle will generate an amount of current while the electric vehicle just starting to regeneratively brake. In order to avoid the impact of high current on the traction battery, a novel electrohydraulic hybrid electric vehicle has been proposed. The main power source is supplied by the electric drive system, and the hydraulic system performs the auxiliary drive system that fully exerts the advantages of the electric drive system and the hydraulic drive system. A proper regenerative braking control strategy is presented, and the control parameters are determined by the fuzzy optimization algorithm. The simulation analysis built the model through the united simulation of AMESim and MATLAB/Simulink. The results illustrated that the optimized control strategy can reduce battery consumption by 1.22% under NEDC-operating conditions.

Оценка функциональной стабильности тормозного управления транспортных средств

The article is devoted to the study of the influence of the brake control elements of passenger vehicles on the stability of their braking properties. The analysis of the influence of uneven braking forces on the wheels of one axle of vehicles on the deviation of the distribution of braking forces between the axles from its calculated value is carried out. When assessing the error in regulating the distribution of braking forces between the axles of vehicles, three components were taken into account: the theoretical error due to the imperfection of the selected control method (the difference between the actual calculated control characteristic from the ideal), the error created due to the instability of the ratio of the braking forces on the front and rear wheels, an additional error caused by the unevenness of the braking forces on the wheels of individual axles, since the fulfillment of the most stringent requirements of international and national standards for the efficiency of braking of vehicles and is inextricably linked with the need to increase the energy consumption of brake mechanisms. The energy consumption of braking mechanisms is understood as the ability of the latter to dissipate the greatest amount of energy of the braking machine without reducing the braking efficiency indicators to the minimum permissible level. Excessive heating of the braking mechanisms leads to a decrease in the friction coefficient μ of the friction surfaces and increased wear of the friction linings, and the brakes are the most unstable element of the braking control, which ensures the absorption and dissipation of the vehicle's energy during braking. The instability of the braking torques on the front and rear wheels, caused by a change in the coefficients of friction of friction pairs, leads not only to a change in the distribution of braking forces between the axles and individual wheels, but also to a decrease in the braking efficiency of vehicles under operating conditions. A method is proposed that makes it possible to assess the quality of regulation of the distribution of braking forces between the axles of a car, taking into account the instability of the braking forces on the wheels.

Development of driver braking control model based on ride comfort index

We propose a new driver braking control model. The driver braking control model is developed based on a ride comfort index. First, a brake model of the experimental vehicle is shown. Next, a driver braking control model is developed by using LQ optimal control. The driver braking control model is designed so that a ride comfort index can become small and ride comfort performance can be improved. Finally, numerical simulations are carried out to show effectiveness of the driver braking control model.