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Collisions between motorcycles and car doors that are being opened are common, preventable accidents that can result in fatalities. A critical limitation of safety advancements in both cars and motorcycles is high cost associated with the use of radar sensors. In this study, a deep learning model was integrated into an inexpensive and camera-utilizing automatic braking assistance system for motorcycles to enhance braking performance and alert motorcyclists to avoid collisions. This research involved two stages: (1) the training of a deep learning model for detecting car door states and (2) the design of safety mechanisms for selecting appropriate braking intensity and front braking ratio values on the basis of the model’s output, time-to-collision, the rider’s braking action, and the initial braking speed, in order to achieve optimal braking performance. Specifically, the YOLOv12s object detection model showed high performance in predicting the states of car doors, exhibiting precision, recall, and mean average precision values of 90.5%, 80.6%, and 87.8%, respectively. The braking intensity of the system was set to 0%, 25%, 50%, or 100% in scenarios involving opening states of the car door (closed, small, medium, or large opening), time-to-collision values, and the rider’s braking action. The optimal front braking ratio function was determined based on the initial braking speed to achieve the optimal braking performance. At an initial braking speed of 60 km/h, the braking stroke under a front braking ratio of 45% was 35.61% and 13.37% shorter than those under front braking ratios of 20% and 60%, respectively. The proposed braking assistance system can feasibly be deployed in the real world because it can respond within a safe time window under the conditions studied, which is approximately 0.5 s. However, further refinement is required, including improvement of the robustness of the object detection model through the collection of a larger and more diverse dataset, experimental measurement of front braking ratios to determine the optimal braking performance in real scenarios, and design of a physical actuator to control braking intensity and the front braking ratio in real time.

A hub motor is an effective drive system for Battery Electric Vehicles (BEVs). However, due to limitations on packaging and cost, there are few applications in which hub motors are taken as the only actuators for a brake vehicle. Most applications involve a Regenerative Braking System (RBS) combined with a Hydraulic Braking System (HBS). In this paper, a top hierarchy Advanced Emergency Braking System (AEBS) controller is designed in Matlab/Simulink and State-flow, including functionalities of basic emergency braking, brake force distribution between front and rear wheels, anti-lock braking and coordination between RBS and HBS based on Model Predictive Control (MPC); a Seven Degrees of Freedom (DOF) BEV chassis model is constructed and rear-end crash test scenarios are created in Carsim with a high and low road adhesion coefficient. A series of comparison tests show that not only are the stopping distances between the ego vehicle and target vehicle shorter, but also the braking torques, longitudinal slip ratio and rotation speed of each wheel are well controlled without wheel locking. To sum up, in addition to meeting the AEBS requirements of avoiding a rear-end collision, the control strategy developed in this paper also levels up braking performance and enhances vehicle stability on both high-mu and low-mu roads for BEVs driven by a hub motor independently.

An innovative friction and permanent magnet combined braking system is the research object of this article and its distribution strategy of braking force was studied. Firstly, three typical distribution strategy curves of braking force were defined, based on the working mechanism of the friction and permanent magnet combined braking system, between the front and rear axles of vehicle. Considering the constraints ofECE regulations, the distribution strategy between the front and rear axles was formulated for the combined braking system, and the distribution strategy within a combined brake was formulated. Secondly, the co-simulation model of whole vehicle with the combined braking system was constructed based on Carsim and Simulink, and a quantitative evaluation index, which is the proportion coefficient of permanent magnet braking, was proposed. Taking continuous braking, low intensity braking and moderate intensity braking as examples, the proposed braking force distribution strategies were simulated and verified. Finally, the test bench was built for the combined braking system, and taking the target braking strength of 0.3 as an example, the performance on anti-heat decay of the combined brake was verified through bench test. The test result shows that the distribution strategies proposed for the combined braking system can fully leverage the advantages of non-contact permanent magnet braking, and the anti-heat decay performance of combined brake is improved.

The purpose of this research was to study the braking behaviors of Cu-based composite pad under real operating conditions of high-speed train. A series of pad-on-disk braking tests was performed with the initial braking speed (IBS) from 80 to 380 km/h. Results showed that the coefficient of friction (COF) of the brake pad demonstrated a three-stage feature with the increase in IBS. It decreased from 0.395 to 0.358 with the increase in IBS from 80 to 200 km/h, then increased to 0.398 when IBS reached 320 km/h; and fell again to 0.379 at 380 km/h. Similarly, the pad also displayed three wear regimes as IBS increased, i.e., (1) mild wear (80–160 km/h), (2) moderate wear (200–250 km/h), and (3) severe wear (300–380 km/h). Surface morphologies and phase analyses indicate that the evolution of the COF mainly depends upon the state of friction film. The formation or completion of friction film regularly contributes to a lower COF and wear rate, while the destruction of friction film results in a higher COF and wear rate. Besides, the “lubricants” induced by high braking temperature are also responsible for the change in the COF. As IBS increased, the key wear mechanisms changed from abrasion, plowing, and oxidation to delamination at 250 km/h.

The friction brake works as an indispensable guarantee for regular work and safety operation of vehicles and industrial equipments. Friction and wear behaviors of brake’s friction materials are considered as an important subject. In this article, friction materials were classified by matrix categories, and their major components were introduced first. Then, the advantages and disadvantages of each friction material were summarized and analyzed. Furthermore, the micro-contacting behaviors on friction interface and the formation mechanism of various friction films were discussed. Finally, the influential rules and mechanism of braking conditions (temperature, pressure, and velocity) on the friction and wear behaviors of friction materials were summarized. It is concluded that the friction film, an intermediate product in braking, is greatly beneficial to protect friction materials from being seriously abraded. The braking conditions have complicated influences on friction and wear behaviors of brake. Generally, the friction coefficient tends to be fairly low while the wear rate increases rapidly under a condition with high temperature, braking pressure, or initial braking speed.

The actual driving conditions of electric vehicles (EVs) are complex and changeable. Limited by road adhesion conditions, it is necessary to give priority to ensuring safety, taking into account the energy recovery ratio of the vehicle during braking to obtain better braking quality. In this work, an electric vehicle with an EHB (electro-hydraulic braking) system whose braking force adaptive distribution control strategy is studied. Firstly, the vehicle dynamics model, including seven degrees of freedom, tire, drive motor, main reducer, battery pack, and braking system, was constructed, which is attributed to the vehicle configuration and braking system scheme. Second, based on curve I and ECE regulations, the adaptive braking force distribution control strategy was formulated by taking the maximum regenerative braking torque as the inflection point, the synchronous adhesion coefficient as the desired point, and the battery SOC, road adhesion coefficient, and braking strength as the threshold. Finally, the vehicle dynamics simulation model was built on the Matlab/Simulink platform, and the simulation results verified the feasibility of the proposed braking force adaptive allocation control strategy. The research shows that the adaptive distribution control strategy can better adapt to the complex and variable driving conditions of the vehicle by combining the inflection point and the desired point. The braking energy recovery ratios of the vehicle under the NEDC and NYCC cycle conditions on a high adhesion road are 52.62% and 47.45%. The braking force distribution curve is close to curve I under the low adhesion extreme road.

During the vehicle exploitation in the conditions of stop and go, or during to the maintain of constant vehicle speed on the long downhills, it comes to the generation of high temperatures on the brake system executive organs. With the correct design of the brake disc, the generation of the excessive temperature can be avoided, what is and the purpose of this study. In order to determine the influence of the brake disc design on the heating, they were analysed four brake discs with different design. One brake disc was a full cross-section disc, while the other three were ventilated brake discs. The ribs shape in the case of the ventilated brake discs were radial, 48 vane and pillar vane. The numerical approach (FEM) was used to investigate the thermal problem (Transient structural module), where ANSYS software was used to achieve this task. The highest temperatures were obtained in the case of the full cross-section disc, while the lowest temperatures were obtained in the case of the ventilated braking disc with 48 vane ribs. The conclusions, which are the result of this research, indicate that the design of the ribs of the brake disc has significant influence on the heating of brake system.

Electric wheel-drive multi-axle heavy-duty vehicles have the characteristics of strong maneuverability and good passability, thereby they are widely used in heavy equipment transportation. However, current research on the composite braking of multi-axle heavy-duty vehicles is rare, which is not conducive to improving braking performance and braking energy utilization efficiency. This work proposes a multi-mode composite braking control strategy for the five-axle distributed electric wheel-drive heavy-duty vehicle. Firstly, given the differences in braking dynamics between two-axle vehicles and multi-axle vehicles, the brake dynamics characteristics of multi-axle vehicles are analyzed, and the vehicle dynamics model of multi-axle vehicles is constructed. Next, a multi-mode composite braking control strategy including a fully electric braking state and hybrid electro–hydraulic braking state is proposed in order to improve the braking energy recovery and braking stability. Finally, a hardware-in-the-loop simulation system is established, and the single-braking conditions and China heavy-duty commercial vehicle test cycle-heavy truck (abbreviated as CHTC-HT) are conducted to verify the performance of the braking control strategy. The results indicate that the recaptured braking energy and braking stability are significantly increased by applying the control strategy proposed in this work.

For road safety, braking system performance has become a very important requirement for car vehicle manufacturers and passengers. To this end, vehicle designers must understand the characteristics of tribological behavior and the causes of their variation in properties. This paper analyzes the tribological behavior (at friction and wear) of the most recent material couples of the braking disk-pad system affected by their structural change through the implications on the braking system stability, reliability and suitable characterizations. Obtaining information to design a very efficient braking system and assessing the influence of the material’s structural changes on its stability has become a necessity. This has been made possible by using several methods of testing a brake disk-pad couple on various devices intended for this purpose. The materials of the contact surface disk-brake pad with their tribological performance (friction, wear), especially the friction coefficient, present particular importance. Also, system components’ reliability, heat transfer and the noise and vibration of the brake disk-pad couple are vital to the correct operation of the braking system and should be given special attention. The test results obtained define the friction patterns and the influence of structural changes and other environmental factors that can be used in computer analysis.

The friction and wear tests of high-speed railway braking materials for a variety of braking speeds (600, 400, and 200 rad/min) at 65% and 98% RH RH (RH: relative humidity) were carried out utilizing a friction-testing machine and humidity generator. The research results indicate that braking speeds and ambient humidity have a prominent influence on the friction and wear characteristics of high-speed railway braking materials. At 65% and 98% RH, the lower the braking speed, the lower the wear rate, and the better the wear resistance property of the braking material. Furthermore, at 600 rad/min, the wear rate of the braking material at 98% RH was smaller than that at 65% RH. However, at 200 rad/min, the wear rate of the braking material at 98% RH was greater compared to that at 65% RH. Concretely, at 600 rad/min, compared with 65% RH, the wear rate to the brake disc at 98% RH was reduced by about 9%, and the brake pin decreased by about 6%. However, at 200 rad/min, compared to 65% RH, the wear rate to the brake disc at 98% RH increased by about 39%, and the brake pin increased by about 37%.