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In this article, a mathematical model is established to determine the working parameters of a hydraulic recoil mechanism, considering the characteristic parameters of the oil. The parameters considered in this study are oil compression and oil temperature. Parameters such as recoil braking force, recoil velocity, recoil length, and recoil time are calculated in the cases of incompressible oil, compressible oil, and different working temperatures of oil. Numerical calculations are applied to 85 mm anti-tank artillery. Calculation results show that oil compression mainly affects the early stages of the recoil movement of the recoil part. When considering the oil’s compressibility, the maximum recoil brake force and maximum hydraulic brake force values are 73406 N, and 61052 N, respectively - reduced by 4.3% and 5.2% compared to the case of uncompressed oil. In addition, the working temperature of the oil also significantly affects the working parameters of the hydraulic recoil mechanism. The calculation results are a reliable theoretical basis for choosing oils suitable for the harsh working conditions of the hydraulic recoil mechanism during maintenance. [ABSTRACT FROM AUTHOR]

This paper details the conceptualization, design, topology optimization, manufacturing, and validation of a hydraulic brake caliper for Formula SAE race cars made of Scalmalloy®, an innovative Al-Mg-Sc alloy which was never adopted before to manufacture a brake caliper. A monoblock fixed caliper with opposing pistons was developed, focusing on reducing mass for a fixed braking force. The design process began with a theoretical analysis to establish braking force and pressure requirements, followed by preliminary design and topology optimization. The caliper was then manufactured using laser powder bed fusion (LPBF). Comprehensive experimental validation, including testing with static and rotating brake discs on an inertial dynamometer, confirmed the expected caliper's performance, with the results showing strong alignment with finite element analysis estimations. In particular, strain and displacement measurements showed excellent correlation with numerical estimates, validating the design's accuracy and effectiveness. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Taking a rear‐wheel drive pure electric vehicle as the research object, considering the safety during braking and improving energy recovery rate, a study was conducted on the distribution strategy of front and rear axle braking force. During the braking process, the feedback braking force of the motor and the hydraulic braking force with an electronic stability controller (ESC) were coordinated and controlled, to ensure that the total required braking force was met. A fuzzy logic controller has been designed, with three variables of battery state of charge, vehicle speed, and braking intensity as inputs, and a modified motor braking ratio as output variable to prevent wheel lockup. Using Cruise software, a co‐simulation model was established with Amesim and Simulink, and simulation validation was conducted on the braking process and cycling conditions. The simulation results showed that the brake recovery strategy based on fuzzy control can effectively improve the vehicle's control performance and energy recovery rate compared to the Economic Commission of Europe regulation. The NEDC (New European Driving Cycle) working condition improved by 10.41% and the CLTC‐P (China Light‐duty Vehicle Test Cycle‐passenger) working condition improved by 10.57%. Effectively improving power consumption per 100 km, NEDC decreased by 1.81% and CLTC‐P decreased by 2.62%. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Vehicle hydraulic braking systems are widely used, structurally complex. Reliability allocation during the design phase is crucial, yet there is a relatively limited body of research on this subject. In response, a new method for vehicle hydraulic braking system is proposed: the comprehensive reliability allocation method based on partial fuzzy ratings and considering failure correlation (CRA-PFRAFC). Based on the analysis of reliability allocation criteria impacting the braking system, the fuzzy set theory is introduced into the comprehensive allocation method, and the criteria with strong subjective dependence are fuzzy evaluated. The braking system allocation model is established by Gumbel Copula function. According to the set reliability target, the model is solved to allocate the failure rates to each subsystem according to the allocation vector. An example illustrates the advantages of this method. The results show that the reliability of the brake assembly is the lowest, while the reliability of the vacuum booster system is the highest. By fuzzy rating the failure severity and failure occurrence, the subjective quantification problem in traditional method is avoided. Meanwhile, compared with the traditional subsystem independent assumption model, this method is more realistic, and the failure rate of subsystem allocation is increased by 20% on average. Therefore, this study provides necessary and effective theoretical basis for reducing the design and manufacturing costs of vehicle hydraulic braking systems. [ABSTRACT FROM AUTHOR]

The main aim of this study was to find ways to increase the performance and life of generator brake linings, which can lead to cost reduction and adequate downtime periods for hydroelectric power plants. First, the dynamic analysis of the linings used in hydraulic turbines was realized and their reactions were examined under different operating conditions. Second, two types of brake linings with different composite components produced in the market were examined metallographically and tested to determine both the stopping performance and durability time of the turbine-generator unit for a sufficient period of time in the vertical 150-megawatt Francis turbine with approximately 500 tons of rotary weight. As a result of these experiments, the lining with the boron component led to much better results than the other brake linings. It has been determined that the boron-containing lining makes 100 stops more than the other lining and stops 20 s earlier in one stop. Therefore, the use of a composite lining with boron content in the braking systems of hydroelectric power plants significantly reduces maintenance incidents and operation costs as it prolongs brake replacement periods in these plants. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Currently, the main solution for braking systems for underground electric trackless rubber-tired vehicles (UETRVs) is traditional hydraulic braking systems, which have the disadvantages of hydraulic pressure crawling, the risk of oil leakage and a high maintenance cost. An electro-mechanical-braking (EMB) system, as a type of novel brake-by-wire (BBW) system, can eliminate the above shortcomings and play a significant role in enhancing the intelligence level of the braking system in order to meet the motion control requirements of unmanned UETRVs. Among these requirements, the accurate control of clamping force is a key technology in controlling performance and the practical implementation of EMB systems. In order to achieve an adaptive clamping force control performance of an EMB system, an optimized fuzzy proportional-integral-differential (PID) controller is proposed, where the improved fuzzy algorithm is utilized to adaptively adjust the gain parameters of classic PID. In order to compensate for the deficiency of single-close-loop control and adjusting the brake gap automatically, a cascaded three-closed-loop control architecture with force/position switch technology is established, where a contact point detection method utilizing motor rotor angle displacement is proposed via experiments. The results of the simulation and experiments indicate that the clamping force response of the proposed multi-close-loop Variable Universe Fuzzy–PID (VUF-PID) controller is faster than the multi-closed-loop Fuzzy–PID and cascaded three-close-loop PID controllers. In addition, the chattering of braking force can be suppressed by 17%. This EMB system may rapidly and automatically finish the operation of the overall braking process, including gap elimination, clamping force tracking and gap recovery, which can obviously enhance the precision of the longitudinal motion control of UETRVs. It can thus serve as a BBW actuator of mine autonomous driving electric vehicles, especially in the stage of braking control. [ABSTRACT FROM AUTHOR]

To guarantee the braking performance and safety of electric vehicles (EVs) and to improve their regenerative energy performance, a regenerative braking recuperation control strategy based on hierarchical coordinated control of an electrohydraulic brake system (eBooster) is proposed in this paper. First, considering the EV braking system characteristics, the eBooster model, vehicle dynamics model and energy recuperation model are established. Then, a hierarchical coordinated control strategy (HCCS) is proposed, and the top-level controller based on model predictive control (MPC) reasonably coordinates the braking torque according to the control objectives and constraints. Additionally, as per the eBooster characteristics, the bottom-level controller adopts a double closed-loop controller to improve the control accuracy and response speed. Finally, verification in the Simulink/AMESim joint simulation environment shows that the eBooster and the HCCS enable combined regenerative and hydraulic braking, which improves brake safety and performance. [ABSTRACT FROM AUTHOR]

Torque vectoring is a widely known technique to improve vehicle handling and to increase stability in limit conditions. With the advent of electric vehicles, this is becoming a key topic since it is possible to have distributed powertrains, i.e., multiple motors are adopted, in which each motor is controlled separately from the others. Moreover, electric motors deliver the torque required by the controller faster and more precisely than internal combustion engines, active differentials and conventional hydraulic brakes. The state of the art of Direct Yaw Moment Control (DYC) techniques, ranging from classical to modern control theories, are analyzed and discussed in this paper. The aim is to give an overview of the currently available approaches while identifying their drawbacks regarding performances and robustness when dealing with common issues like model uncertainties, external disturbances, friction limit and common state estimation problems. This contribution analyzes all the steps from the lateral dynamics reference generation to the desired control action computation and allocation to the available actuators. In addition, some of the presented control logic is evaluated in a simulation environment for a passenger car. Results of both open-loop and closed-loop maneuvers allow the comparison and clarification of each control strategy's key advantages. [ABSTRACT FROM AUTHOR]

This article addresses the braking controls for an electric vehicle with DC motors such that the voltage in the motors is used for controlling the wheel angular velocity. Other papers on the anti-lock braking system (ABS) handled how to derive the braking torque (or braking pressure) for controlling the wheel angular velocity. However, heavy or prolonged braking can cause brake fade or wear. According to EURO 7 regulations, brake fade or wear is not desirable, since the regulations refer to the reduction in particles emitted from brake pads. For avoiding heavy or prolonged braking, this paper does not use a brake unit, such as electro-mechanical brake units or hydraulic brake units, for vehicle stop. Instead, the motor voltage is used for controlling the wheel angular velocity. While a vehicle moves, the goal of this paper is to provide automatic braking controls in real time, so that the vehicle stops safely and smoothly without slippage before colliding with an obstacle. In practice, road conditions can change depending on weather conditions, such as rain or snow. Moreover, road slope can have an effect on the braking distance for the vehicle. Thus, this article introduces automatic braking controls, while considering both road slope and road conditions. This article is unique in presenting automatic braking controls for the smooth stop of electric vehicles with DC motors, while considering both road slope and road conditions. In addition, this article is unique in controlling the motor voltage for controlling the wheel angular velocity, while not requiring any brake units. [ABSTRACT FROM AUTHOR]

Based on the principle of eddy current braking and hydraulic braking, a new eddy current-hydrodynamic hybrid retarder (ECHHR) is proposed. Based on the introduction of the working principle and structure of the ECHHR, the finite element analysis models of the electromagnetic field and the flow field of the ECHHR were established, respectively. The electromagnetic field distribution, the flow field velocity, and the flow field pressure in the ECHHR were numerically simulated. The air gap magnetic density, the eddy current braking torque, and the hydraulic braking torque under different excitation currents and different liquid filling rates were calculated. Finally, the braking performance of the EHHR was tested via experiments, and the effectiveness of the finite element analysis method was verified. The test results indicated that as the speed increased, the composite braking torque of the ECHHR increased approximately linearly. When the speed was 1000 r/min, the composite braking torque reached 2100 N·m. Compared to separate hydraulic braking and eddy current braking, the composite braking torque was relatively high in the full-speed range. [ABSTRACT FROM AUTHOR]

The brake system requires careful attention for continuous monitoring as a vital module. This study specifically focuses on monitoring the hydraulic brake system using vibration signals through experimentation. Vibration signals from the brake pad assembly of commercial vehicles were captured under both good and defective conditions. Relevant histograms and wavelet features were extracted from these signals. The selected features were then categorized using Nested dichotomy family classifiers. The accuracy of all the algorithms during categorization was evaluated. Among the algorithms tested, the class-balanced nested dichotomy algorithm with a wavelet filter achieved a maximum accuracy of 99.45%. This indicates a highly effective method for accurately categorizing the brake system based on vibration signals. By implementing such a monitoring system, the reliability of the hydraulic brake system can be ensured, which is crucial for the safe and efficient operation of commercial vehicles in the market. [ABSTRACT FROM AUTHOR]

Due to the difference of time‐domain response between hydraulic braking and regenerative braking, as well as changes of equivalent parameters and operating parameters during braking mode switching, it is liable to cause torque fluctuation, which affects braking safety and vehicle ride comfort. First, the uncertainties of vehicle load and frictional coefficient model are investigated. Second, the hybrid system theory is applied to provide state transfer condition for mode switching strategy. Finally, the control strategy that utilizes regenerative braking torque to compensate for difference of the required braking torque is designed, and a new μ‐H∞ control algorithm through D‐K iteration is presented to improve the robust performance. The proposed μ‐H∞ control strategy is examined under various braking situations, and the results indicate that (1) the μ‐H∞ controller have the advantage of robustness performance, the amplitude of regenerative braking is decreased by 6.14%, and the steady‐state error of hydraulic braking is decreased by 5.26% over the H∞, and (2) under the braking mode switching, the designed compensation control strategy has the performance of fast and accurate tracking of the desired torque, and the steady‐state error does not exceed 3.5%. [ABSTRACT FROM AUTHOR]

Featured Application: The proposed braking intention identification control strategy has braking stability. As a widely-used construction machinery, the electric loader has the potential to recover braking energy due to its large mass and frequent starts and stops. Identifying braking intention accurately is the foundation of braking energy recovery. The typical braking condition of an electric loader is analyzed; the braking intention is divided into sliding brake, mild braking, moderate braking, and emergency braking. A large number of braking data were collected under different braking intentions, which are used as the basis for fuzzy control variable partitioning, fuzzy controller parameter setting and fuzzy control rule formulation. The control strategies of deceleration intention identification based on accelerator pedal, braking intention identification based on brake pedal and sliding brake intention identification are proposed in this paper, respectively. This paper takes the hydraulic brake pressure as a feedback parameter, even if there is hysteresis or failure based on the intention of pedal identification, the system can still provide sufficient braking strength to ensure the braking safety. The AMESim(R12)-Matlab/Simulink co-simulation model and prototype are built to verify the feasibility of the control strategy under different braking intention identification. The results show that the braking strength under stronger braking intention can satisfy the braking demand whether at a speed of 2 m/s or 12 m/s, which ensures the safety of emergency braking, and the electric loader can provide stable braking strength under different braking intention and different speed. This has good braking stability. [ABSTRACT FROM AUTHOR]

In this paper is presented a methodology of systemic design and control of a synchronous generator with hybrid excitation for the generation of wind energy. The design of the generator is made by the analytical method taking into account the interactions of the global system. Indeed, the regulation of the speed of the turbine is ensured by adjustment of the excitation current to regulate the electromagnetic torque and in this case the excitation current is limited to a fixed value since the increase of excitation current leads to an increase generator's phase currents magnitude. The increase of the phase's currents of the generator is linked to the increase of the amplitude of the electromotive forces depending on the excitation current. Therefore, to limit the amplitude of the phase's currents to the value of the design current fixed by the note book specifications for a given power of the wind turbine, it is necessary to limit the excitation current by limiting the supply voltage of the DC-DC converter used to vary the excitation current for the regulation of the electromagnetic torque. This technique of speed adjustment is simpler and less expensive than techniques using mechanical and hydraulic braking systems. [ABSTRACT FROM AUTHOR]

The full hydraulic braking systems have gradually replaced the traditional mechanically actuated brake systems due to their increased performance, reliability, and safety. Besides their excellent characteristics, the functional performance of individual components, the correlation of their performance parameters, and energy consumption are not fully explored. In this paper, An Advanced Modeling Environment for performing Simulation of engineering systems (AMESim) simulation model of a fully hydraulic braking system is developed and validated, and the sensitivity of different parameters to the system performance is predicted. The multi-factor comprehensive optimization analysis was carried out from the system level for the first time. The brake energy consumption and interaction time are evaluated through a Genetic Algorithm (GA) considering a multi-factor coupling condition. The optimization results revealed that the outlet pressure and braking pump power are reduced by 35.6%, the energy consumption is reduced by 32.8%, and the braking times are increased by 10%. [ABSTRACT FROM AUTHOR]

Featured Application: The proposed energy recovery structure control strategy can improve the energy efficiency of an electric loader. The loader has a lot of recoverable braking energy due to its larger mass and frequent starts/stops. For a 5-ton pure electric drive loader, an emergency braking intention recognition strategy based on hydraulic braking pressure was proposed. The braking intention recognition strategy of an acceleration pedal and brake pedal was used to distinguish different braking intentions, and the hydraulic braking system pressure was used as a feedback parameter for emergency braking intention recognition to improve braking safety. Aiming at electro-hydraulic composite braking mode switching, a collaborative control strategy of walking regenerative braking and mechanical braking is proposed. Simulation analysis by AMESim and vehicle test results show that the proposed control strategy can realize driver braking intention recognition and electro-hydraulic braking force distribution under different working conditions and improve braking smoothness. According to the calculation of the energy recovery effect evaluation index, the energy recovery efficiency is up to 71.64%, the braking recovery rate is above 42.50%, and the maximum energy saving for the whole vehicle is 7.58% under one cycle condition. The proposed strategy has a good energy-saving effect. [ABSTRACT FROM AUTHOR]

The traditional traction control system (TCS) based on hydraulic braking only works when the wheels are slipping, which will cause the problem of slow response to extreme slip. In addition, the TCS of four‐wheel‐independent‐drive electric vehicle (4WIDEV) is often based on road adhesion characteristics identification or optimal slip ratio identification to implement active control, which is difficult to achieve in engineering. Aiming at this problem, a practical active TCS is proposed in this paper. Firstly, according to the wheel slip state of the front and rear axles, the dynamic transfer of torque between axles is realized to maintain the vehicle propulsion power. Second, the adhesion conditions between road and tire are classified, and two sets of target slip ratio thresholds are formulated for high and low adhesion pavement, respectively. Then the current road adhesion coefficient is estimated by using the advantage that the in‐wheel motor torque can be obtained in real‐time. Thirdly, the overall framework of the control strategy is established, the logic threshold control algorithm is adopted for tracking the wheel target slip ratio. Finally, the simulation results show that the proposed active TCS can improve the vehicle power and avoid excessive wheel slipping. [ABSTRACT FROM AUTHOR]

The friction vibration signal corresponding to different fault types of brakes is significantly different, thus a hydraulic disc brake fault diagnosis and judgment scheme based on vibration signal detection was proposed and validated in the paper. According to the composition and electric control principle of hydraulic brake, the vibration signal detection and brake pressure control strategies were established. The key hardware and isolation circuit of the detection system were designed, which can effectively improve the stability and anti-interference ability in the process of vibration data acquisition and transmission with SPI and CAN bus communication scheme. In order to eliminate noise interference in friction vibration signal and improve the accuracy of fault diagnosis with advantage, wavelet threshold denoising method was applied to brake disc vibration signal processing. The denoised signal can be obtained by inverting the selected wavelet coefficients to separate the useful components of the signal from the invalid noise. For the research on the correlation between fault types and vibration signal characteristics, a friction vibration test bench for hydraulic braking system was built to obtain and process the output signal from vibration sensor. The frequency spectrum response laws of vibration signals were compared and analyzed when the brake disc was normal and had surface defects, including microcracks, excessive wear and fatigue peeling. The external parameters such as brake pressure and spindle speed were keeping constant, thus eliminating the influence of working factors on vibration characteristics. In order to study the influence of brake pressure failure on friction vibration, the variation law of vibration signal is compared and analyzed under the condition of hydraulic valve leakage and pressure maintaining failure. The results show that the friction vibration signal can be used as an effective basis forjudging the surface defects and brake pressure faults of brake discs. Under the condition of wavelet threshold denoising, accurate and effective vibration parameters can be obtained, which is of great significance to the safety and reliability of the braking system. [ABSTRACT FROM AUTHOR]

Studies have shown the topical domestic use of hydraulic brake fluid and it has been reported by domestic users as efficacious against skin infections, especially dermatophytosis. Hydraulic brake fluid ointment is a combination of hydraulic brake fluid and a 30 g weight of simple ointment formulation. Its MIC on T. rubrum was determined using the micro-broth dilution method and a solid culture medium gave three different volumes of 0.2, 0.4, and 0.8 ml which were used to prepare percentage formulations of 30 g simple ointment. A total of 28 male albino rats (pathogen-free, 6-8 weeks old) weighing between 180-210 g, randomly divided into 7 groups of 4 rats each, was used for this experiment. The first and second groups received 30 g simple ointment administered constituting the negative (without dermatophytosis) and positive (with dermatophytosis) control groups. The third, fourth and fifth groups received 0.7, 1.3 and 2.7% formulation of the test agent in the simple ointment, respectively; the sixth group was topically given 0.2% ketoconazole gel; the standard group while the seventh group received 0.25 ml (equivalent to a drop) of hydraulic brake fluid (neat) without a simple ointment base applied on the infected paws of the group. Application was from the 10th day of post-infection and lasted for 2 weeks. Clinical response and fungal scores were significantly lower (p < 0.05) in T. rubrum - induced albino rats treated with 1.3, 2.7, and 0.25 ml (neat) concentrations of the test agent compared to infected non-treated group administered simple ointment alone. The test agent (2.7%) produced a clinical response similar to standard drug (ketoconazole). [ABSTRACT FROM AUTHOR]

To solve the problems of high power consumption and insufficient driving range of pure electric rear-drive commercial vehicle, a braking energy recovery method for the pure electric rear-drive commercial vehicle was proposed. The original H-type hydraulic pipeline layout of the brake system was kept, and the fixed ratio distribution of the front and rear axle hydraulic braking force was unchanged.Only one brake pedal force sensor was added, and the braking energy recovery strategy was proposed based on ECE R13 and I curves. AVL Cruise and Simulink were used to establish a joint simulation platform for vehicle, and a strategic model and a typical series scheme model with greatly increasing costs were built and compared. Under three typical conditions, the vehicle brake energy recycling simulation test was conducted. The results show that the proposed braking energy recovery control strategy with load identification can approach the upper limit of recovery within the safety limit at low cost, and the driving distance can be increased by more than 21.00% compared with the original design at full load. [ABSTRACT FROM AUTHOR]