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Heavy-duty vehicles are generally equipped with non-contact hydraulic retarders or eddy current retarders to ensure safe driving during downhill conditions. The torque of the hydraulic retarder is large when the rotor rotates at a high speed, but the torque is small when the rotor rotates at a low speed. As another commonly used retarder, the eddy current retarder has a large torque at a low speed and a low power density at a high speed. High torque at full speed is the vehicles’ requirement for the auxiliary brake system, with no retarders can achieve this goal perfectly alone. Encouragingly, the braking performances of these two kinds of retarders are complementary. Based on the above properties, the eddy current-hydraulic hybrid retarder (EHR) is designed applying the principle of eddy current and the principle of hydraulic braking. In this novel HER, both sides of the rotor are used for hydraulic braking, and the outer ring of the rotor generates eddy currents. The finite element models of the flow field and the electromagnetic field are established separately and solved by computer to predict the braking torque of the EHR. The prototype was developed and the braking performance of the EHR was obtained through the bench tests. Comparing the theoretical calculation results and experimental data, the braking characteristics of the EHR are analyzed. At low speed, the EHR mainly relies on the eddy current braking, whereas at high speed, it relies on both eddy current and hydraulic braking. Moreover, the control of the EHR can be realized only by adjusting the braking torque of the eddy current part, which simplifies the control system. [ABSTRACT FROM AUTHOR]

Some recent accident reports involving large vessels in mooring operations or breaking away from their moorings conclude that brakes of mooring winches do not render before line parts. As the potential loss of life is high, the utmost attention on-board must be paid to minimise this inherent risk. When the load on the mooring lines becomes overloaded beyond the pre-set levels, mooring winches band brakes have the safety function of rendering and allowing the line to shed this load before its potential breaking and the subsequent snap-back. As a preventive measure against breaking, the pre-set level, known as Brake Holding Capacity (BHC), must be below the Minimum Breaking Load (MBL) of the line. In this paper, the authors analyse concerns that can arise from those with conventional screw manually-applied band brakes regarding their BHC reliability. Thus, in order to improve safety, the advantages of the spring-applied band brakes with manual setting and release or with hydraulic release are highlighted. Finally, the paper shows a typical procedure using a hydraulic jack for brake testing the winch of a Liquefied Natural Gas (LNG) ship to fix their BHC in order to hold 60% of the MBL of the mooring line. [ABSTRACT FROM AUTHOR]

This study designs one kind of hydraulic auto-brake-valve calculates its driving force and velocity, simulates its braking force and stability, in order to accomplish auto brake in the landing condition and keep braking in cruising condition of the unmanned aerial vehicle. The auto-brake-valve uses a servo motor to drive lead screw and nut. The output press of the auto-brake-valve is changed by the variation of rotate speed and direction of servo motor, that can be completed the control of the brake device. [ABSTRACT FROM AUTHOR]

In this study, modifying a constant speed–driven hydraulic press brake machine into a variable speed drive system is examined in terms of electricity saving, CO2 reduction, and economic perspectives. The goal of the modification is to obtain increased efficiency by adding minimum hardware and software tools. For realizing this goal, a hydraulic test rig operated in a manner to represent the cycle of a specified press brake machine is taken into consideration, which is equipped with a frequency controller on an induction motor and an electro-hydraulic load sensing. Then, the amount of electricity saving is determined experimentally under wide-range operating conditions. Besides, an economic analysis is performed based on 5 different scenarios to represent the conditions of the real industry throughout an operation year. As a result, the amount of electricity saving is observed to vary between 3 and 19% depending on the operating conditions. In addition, it is determined that there is 1.75 to 10.5 tons of CO2 reduction potential per year. The payback period of the modification investment is computed between 1.51 and 4.67 years, according to the considered scenarios. In the sensitivity analysis, the most important parameters affecting the economic criteria are discount rate, electricity unit price, and initial investment cost. [ABSTRACT FROM AUTHOR]

The braking quality is considered as the most important performance of the adaptive control system that influences the vehicle safety and ride comfort remarkably. This research is aimed at designing an adaptive cruise control (ACC) system based on active braking algorithm using hierarchical control. Taking into account the vehicle with safety and comfort, the upper decision-making controller is designed based on model predictive control algorithm. Throttle controller and braking controller are designed with feedforward and feedback algorithms as the bottom controller, where the braking controller is designed based on the hydraulic braking model. The whole model is simulated collaboratively with Amesim, Carsim, and Simulink. By comparison with the full deceleration model, the results show that the proposed algorithm can not only make the vehicle maintain a safe distance under the premise of following the target vehicle ahead effectively but also provide favorable driving comfort. [ABSTRACT FROM AUTHOR]

With the development of large‐scale wind power generation and offshore wind energy, reducing the nacelle weight and the gear failure rate is increasingly important. Hydraulic transmission is characterized by its flexible layout and transmits large energy with small volume and weight, which suits the demands of wind power generation. In this paper, a thorough review of hydraulic technology application in wind energy is carried out, in the aspect of pitch, brake, yaw, transmission, new applications, and the potential problems. [ABSTRACT FROM AUTHOR]

A novel compact initiative braking system orienting intelligent vehicles and autonomous driving is revealed. The delicate arrangement of on–off switch valves guarantees precise hydraulic pressure modulation. Integrated stroke simulator provides a well-tuned pedal force feedback. The fallback level is intensively designed to be nondegraded. A hierarchical control frame with the underlying hydraulic controller is designed to govern operation procedures. The underlying hydraulic controller is set up based on adaptive gain scheduling proportion differentiation controller and logic threshold control. Hardware-in-loop tests are carried out in full perspectives. The test result of slope-sine combination tracking shows that, compared with the conventional proportion integration differentiation controller, the designed underlying controller achieves higher pressure modulation accuracy with no chattering effect. Controller robustness to accumulator pressure fluctuation is proven by the dual-cylinder tracking test. A batch of step-response tests under different accumulator pressures shows a rapid pressure building capability in emergency situations under all pressure range. The fail-safe test result indicates that the conventional hydraulic brake can be restored in 1.5 s with the operation of the driver, which significantly increases the margin of brake safety for highly autonomous vehicles. The regenerative braking test result suggests the immense potential of the developed system in an application to electrified vehicles. [ABSTRACT FROM AUTHOR]

Brake-bleeding is the process of removing air bubbles present on hydraulic brake systems. In particular, the existence of air content within the EPB caliper deteriorates bleeding performance, causing a high-level compressibility of the brake fluid. This paper presents numerical and experimental investigations of the effect of holes on brake-bleeding performance improvement for three different nut-spindle models included in the driving-part model of the EPB caliper. In the present paper, compressible brake-fluid simulations with pressure rise and drop ranging in pressure from 0 to 100 bar are modelled with a transient numerical approach utilizing a three-phase mixture model and standard k-ω turbulence model. The experimental verification of the effect of the holes with a constant 2 mm diameter, determined from the simulation results, was conducted using a standard test device at Mando Corporation. In conclusion, the experimental results prove that the effect of the holes has considerable impact on the performance improvement. [ABSTRACT FROM AUTHOR]

This study deals with the development of drum brake liner for a multi-utility vehicle possessing a hydraulic brake system by varying 7 weight % of steel fiber and stainless steel fiber each, in friction composite formulations. The developed friction composites were tested for physical, chemical, corrosion, mechanical, thermal properties, and tribological characteristics, under near-actual conditions using an inertia dynamometer as per industrial standards. Finite element analysis software (ANSYS) analysis was performed to show the thermal stress distribution of the developed friction composites at the maximum temperature rise due to heat generated during brake stops, and an extensive evaluation method was used to rank the composites. The study concludes that the brake factor of the stainless steel fiber-based friction composite produces stable performance in all conditions with a lower liner temperature rise of 340 °C and lower thermal stress at 4.255294 MPa. However, the steel fiber-based composites produced high performance at the beginning but deteriorated after a certain period due to higher levels of corrosion and a high temperature rise of 361 °C resulting in a negative fade (−0.84%) and more thermal stress (5.619102 MPa). The primary plateau, secondary plateau, back transfer of drum wear debris, and the distribution of constituents on the worn surface of the developed composites in a resin matrix were identified and studied using a scanning electron microscope (SEM) equipped with energy-dispersive spectroscopy. [ABSTRACT FROM AUTHOR]

To solve the problem of static pressure transmission performance of electronic hydraulic brake system, the mathematical models of main cylinder, solenoid valve, accumulator, and motor hydraulic pump of electronic hydraulic brake system are established. Based on the mathematical model, the static pressure transmission performance of electronic hydraulic brake system is analyzed. Then the standard normal state model of static pressure transmission performance of electronic hydraulic brake system is established by statistical method. The threshold correlation degree between the vibration signal of the static pressure drive and the normal state mode obtained by the vibration acceleration sensor are calculated. If the threshold correlation degree is greater than or equal to 0.5, the precision pressure transmission state of the electronic hydraulic brake system to be tested belongs to the standard normal state, and the threshold correlation degree is less than 0.5, indicating that the precision pressure transmission state of the electronic hydraulic brake system to be tested does not belong to the standard normal state. The test results show that the proposed method can effectively detect the boost response of the static pressure transmission of the electronic hydraulic brake system under high and low strength conditions under normal conditions and accumulator failure conditions. The method can effectively detect the static pressure transmission state of the electronic hydraulic brake system belongs to the fault state according to the threshold correlation degree, which is consistent with the simulation results. [ABSTRACT FROM AUTHOR]

A double-loop optimal control strategy combined with a voltage variable charging control scheme is developed to enhance the efficiency of energy recovery and improve control precision for a regenerative hydraulic composite braking system. The proposed voltage variable charging control scheme structure aims to regulate a regenerative braking torque using a charging voltage variation based on an existing battery management system. In addition, an experimental test was conducted to verify the effectiveness of the charging voltage control, and a first loop optimal control was developed to evaluate the ideal ground braking force accurately by transforming several state variables into differential equations. A second optimal control loop was subsequently developed to track an ideal slip ratio using a full-information optimal sliding mode control method under the all-braking conditions. Simulation results corroborate that a composite braking system controlled by the proposed control strategy can implement the regenerative braking behavior precisely with a considerable high-energy recovery efficiency. [ABSTRACT FROM AUTHOR]

Significant nonlinearity of electronic hydraulic brake (EHB) systems often leads to complex hydraulic force control responses. This paper designs a motor-driven EHB system and analyzes nonlinear friction induced by the deceleration mechanism. To compensate this friction, a flutter signal is added to the controller input. In addition, this paper designs a fuzzy-PI (Proportional and Integral) controller for the cylinder hydraulic pressure of the EHB system based on the opening and closing characteristics of a solenoid valve. Response curves of cylinder hydraulic pressure are obtained under three different input signals: step, triangular, and sinusoidal. The co-simulation model is established by AMEsim™ and Simulink® ansofts. The study results indicate that the proposed hydraulic-force-following control method of the EHB system can follow different input signals well. A step response test and a sine-wave-following test are carried out, which correspond to the EHB response in the case of driver's emergency braking and frequent braking, respectively. Stable and rapid pressure build-up is obtained under different step target hydraulic pressures. Therefore, the hydraulic-force-following control method of the EHB system based on a fuzzy-PI controller can satisfy the EHB system accuracy requirements for an electric vehicle, which is a certain valuable for the automobile industry. [ABSTRACT FROM AUTHOR]

The purpose of this study is to analyze the hydraulic compound power system and energy system of parallel hydraulic hybrid electric vehicle and discuss its advantages in vehicle braking and energy recovery. In this research, the hydraulic hybrid power system of the power vehicle was summarized, the internal combustion engine, secondary components, clutch and accumulator in the system were described, and the mathematical model was established according to the characteristics. In addition, the braking energy feedback principle of hybrid electric vehicle was introduced, which lay a foundation for the analysis of energy recovery strategy. The results showed that when the vehicle was braking, the hydraulic regenerative braking system was recovered the energy and the pressure of accumulator was increased. When the car was started, it was driven by the hydraulic regenerative braking system, and the pressure of the accumulator was reduced. Therefore, electric vehicles can fully recover the energy consumed by traditional vehicles during braking by adding the hydraulic regenerative braking system, and store the energy in the hydraulic accumulator. When the car was started or accelerated, the stored energy was released to save energy and reduce carbon emissions, so that the efficiency of energy and heat utilization was significantly improved, and the endurance was enhanced. [ABSTRACT FROM AUTHOR]

This study investigates the efficiency and safety of regenerative brake energy recuperation systems for electric vehicles. A three-input single-output fuzzy controller is developed to allocate hydraulic and electric braking forces, considering brake intensity, vehicle speed, and battery SOC's impact on regenerative braking performance. Fuzzy neural networks are utilized due to their effectiveness in solving complex, nonlinear, and fuzzy systems, along with their robustness to parameter changes and external disturbances. The fuzzy process of the controller is optimized using a self-tuning algorithm for designing membership function parameters, resulting in a fuzzy neural network controller. Moreover, electric and hydraulic braking forces are redistributed. Simulation using AVL Cruise software is conducted under NEDC and FTP-75 working conditions. The suggested brake energy recovery control approach using fuzzy neural networks successfully recovers braking energy, achieving energy recovery efficiencies of 14.52% and 39.61% under NEDC and FTP-75 conditions, respectively. [ABSTRACT FROM AUTHOR]