Hydraulic Braking Research Articles

Research on New Automotive Electronic Hydraulic Brake System

The new structure of EHB replaces part of the mechanical transmission by electronic control, brake pedal is not connected with brake wheel cylinder directly. While braking, ECU collect the sensor signal of brake pedal as the driver’s intention. It solves the problems caused by traditional hydraulic braking system, and also makes up for deficiencies caused by the traditional braking system design and principle. The EHB system can make brake control gets the maximum control margin, which can improve the efficiency and braking safety.

Adaptive Cruise Control Strategy Design with Optimized Active Braking Control Algorithm

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.

Pressure Estimation and Pressure Control of Hydraulic Control Unit in Electric-Wheel Vehicle

In order to improve the braking performance and safety performance of electric vehicles driven by a hub motor, the cylinder pressure estimation and pressure control of its hydraulic braking system are studied. In this paper, a mathematical model is established for the solenoid valve, a key component of the hydraulic actuator, and the hydraulic and electrical characteristics of the solenoid valve are studied. A state equation is established for the solenoid valve, and the square root volume Kalman filter (SRCKF) algorithm is used to estimate the solenoid valve spool position. The brake fluid flow and brake wheel cylinder pressure are calculated based on the spool position. Finally, a solenoid valve spool position control algorithm based on sliding mode variable structure algorithm is designed, and the brake pressure in the brake wheel cylinder is controlled by adjusting the spool position. Matlab/Simulink-AMESim software simulation and hardware-in-the-loop were used to verify the algorithm. Simulation results show that the brake cylinder pressure can be estimated accurately, and the pressure control algorithm can accurately follow the control target value.

Simulated Braking Performance Comparison of an Electric Drum Brake and a Hydraulic Drum Brake Systems

The most important safety equipment for the operation of a vehicle is the brake equipment. This research attempts to develop an all-electric braking system that can be used in an electric vehicle. Since the drum brake requires lower actuation input than the disk brake in order to deliver the same amount of braking force. It seems logical to be used in the electric vehicle as far as minimizing energy usage is concerned. The proposed electric drum brake system conceptually is not new as it has been used as a trailer brake for a tractor-trailer vehicle. Adopting the trailer brake for a passenger vehicle requires proper downsizing and different braking control scheme. This paper presents the modelling and simulation results of the proposed electric drum brake. The main interest is its braking performance which can be investigated by the brake force profile or the brake force characteristic. The results are compared with the braking performance of the conventional hydraulic drum brake system which is using validated data from the literature. The simulation results show that the braking force of the electric drum brake system is two times higher than that is of the hydraulic drum brake system subjected to the same actuation force. The results from this paper will be valuable for the development of the controller in the future.

Optimal Anti-Lock Braking Control With Nonlinear Variable Voltage Charging Scheme for an Electric Vehicle

An optimal anti-lock braking control strategy using nonlinear variable voltage charging scheme for an electric-wheel vehicle is developed with aim of improving energy recovery efficiency on the premise of vehicle safety under the critical braking situation. A variable voltage charging control scheme is proposed with its operational principles to obtain maximum energy recovery as well as to balance the energy differences of each battery cell during the anti-lock braking. Given the nonlinearity of in-wheel motor, the nonlinear variable voltage charging control law is obtained on the basis of parameters fitting via experimental data. An ideal regenerative braking torque calculated by the nonlinear variable voltage charging control law is set as one of the disturbance vectors and an optimal sliding mode–anti-lock braking control strategy is developed to provide optimal hydraulic pressure for anti-lock braking system. In this manner, the torque allocation process is omitted by using a compensation control of the hydraulic braking torque. Simulation results corroborate the effectiveness of the proposed optimal anti-lock braking control strategy with higher energy recovery efficiency.

Study on intelligent control of yaw stability of electric vehicle with in‐wheel motors

In order to improve yaw stability of electric vehicles with in-wheel motors, a yaw moment fuzzy control method based on yaw rate and side-slip angle is designed. A hierarchical control structure was set up. The upper layer is motion tracking layer, it obtains required additional yaw moment based on the fuzzy control theory according to current status feedback of vehicle and ideal status of reference model. The lower layer is a torque distribution layer that uses the weighted least squares method to optimise moment distribution by adopting an in-wheel motors/hydraulic brake system combined control strategy, with full consideration of all restraints. A rapid control prototype test bench is designed based on dSPACE system, simulation experiments were conducted under typical test work conditions. The simulation result shows that compared with even torque distribution and the optimal torque distribution involving the motor only, the optimal torque distribution control strategy of the combined in-wheel motor and the hydraulic braking system can effectively improve the stability of wheel-motor driven electric vehicles.

Research on energy-saving characteristics of battery-powered electric-hydrostatic hydraulic hybrid rail vehicles

With the advantages of no emission and low noise, battery rail vehicles (BRVs) are widely used in the construction of subway, high-speed railway and so on. However, the problems of low energy efficiency and peak power shock of traction motor have severely restricted the application and promotion of BRVs. To address these problems, an electric-hydrostatic hydraulic hybrid powertrain (EH3) is designed in this paper. Friction braking (FB) is replaced by hydraulic regenerative braking (HRB) and the mode of recovered hydraulic energy coupled at the inlet of pump (ECIP) to assist acceleration is proposed. The energy conservation characteristics of recovery and coupling of hydraulic energy in EH3 powertrain are verified by simulation and laboratory test bench. The energy recovery efficiency of HRB is up to 50% and the new coupling modes can greatly reduce the consumption of electric power. The control strategy is designed to coordinate different working modes which are established based on the high-pressure accumulator (HPA) and the driving state parameters of BRVs. The simulation result shows that the energy consumption of the battery can be reduced by 17.32%. The EH3 powertrain has broad application prospects in realizing energy conservation, reducing peak motor power shock and improving the braking performance of BRVs.

Mechatronic approach in hydraulic braking system

In present automotive sector there are magnificent transformations from mechanical to electrical with intensive changes. Each and every one is showing enthusiasm towards vehicles. In addition, humans are very much fascinated towards vehicles where they are driving faster than before. Many types of braking system have been introduced but this paper explains whether the brakes can be applied with less human effort by removing the solid linkage present in between pedal and master cylinder. In order to make the braking system economical and affordable, we are introducing a mechatronic technique which helps us in eliminating the solid linkage present in between the pedal which is linked to master cylinder, linking the pedal to linear potentiometer for the resistance. As the resistance starts varying, difference in braking will be observed. This technique helps in reducing manual effort. Working will be effective and efficient if the components are given more than recommended power supply.

Retraction: Experimental investigation of the vacuum-actuated brake system compared with hydraulic brake system in a vehicle

In this study, a new vacuum brake system has been designed in the place of conventional hydraulic braking system for a Light Commercial Vehicle (LCV). An attempt has been made to reduce the braking...

Torque Coordination Control of an Electro-Hydraulic Composite Brake System During Mode Switching Based on Braking Intention

The electro-hydraulic composite braking system of a pure electric vehicle can select different braking modes according to braking conditions. However, the differences in dynamic response characteristics between the motor braking system (MBS) and hydraulic braking system (HBS) cause total braking torque to fluctuate significantly during mode switching, resulting in jerking of the vehicle and affecting ride comfort. In this paper, torque coordination control during mode switching is studied for a four-wheel-drive pure electric vehicle with a dual motor. After the dynamic analysis of braking, a braking force distribution control strategy is developed based on the I-curve, and the boundary conditions of mode switching are determined. A novel combined pressure control algorithm, which contains a PID (proportional-integral-derivative) and fuzzy controller, is used to control the brake pressure of each wheel cylinder, to realize precise control of the hydraulic brake torque. Then, a novel torque coordination control strategy is proposed based on brake pedal stroke and its change rate, to modify the target hydraulic braking torque and reflect the driver’s braking intention. Meanwhile, motor braking torque is used to compensate for the insufficient braking torque caused by HBS, so as to realize a smooth transition between the braking modes. Simulation results show that the proposed coordination control strategy can effectively reduce torque fluctuation and vehicle jerk during mode switching.

Study on Braking Characteristics of a Novel Eddy Current-Hydraulic Hybrid Retarder for Heavy-Duty Vehicles

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.

Designing and Analyzing the Brake Master Cylinder for an ATV vehicle

A braking system is a means of converting momentum into heat energy by creating friction in the wheel brakes. The braking system which works with the help of hydraulic principles is known as hydraulic braking systems. The most frequently used system operates hydraulically, by pressure applied through a liquid. These are the foot-operated brakes that the driver normally uses to slow or stop the car. Our special interest in hydraulics is related to the actions in automotive systems that result from pressure applied to a liquid. This is called hydraulic pressure. Since the liquid is not compressible, it can transmit motion. A typical braking system includes two basic parts. These are the master cylinder with the brake pedal and the wheel brake mechanism. The other parts are the connecting tubing, or brake lines, and the supporting arrangements. The present paper is about designing of Twin master cylinder system for an all-terrain vehicle and doing a feasibility study of its strength using ANSYS. Our work is focused on reducing weight which is one of the factors to increase efficiency. Reduction in weight and space, due to its compactness. The twin Master cylinder system is a great advancement in the braking system for an ATV. 3-D CAD modeling is done using SOLIDWORKS 2017, whereas the analysis of its strength is done using ANSYS.

Experimental Investigation on Effects Accumulator Initial Pressure, Pump Displacement and Vehicle Speed on Regeneration Efficiency of the Hydraulic Regenerative Braking System

Recently researchers are focus on evaluation of hydraulic regenerative braking systems for improving fuel economy and reducing pollutant emissions. Present work is oriented to study effects of variation in vehicle speed at braking, accumulator initial pressure and pump displacement on regeneration efficiency of hydraulic regenerative braking system (HRBS) on the school van conveyance in Vadodara city. The results show that the HRBS regeneration efficiency improves between 1.7 to 10% with reduction in initial pressure from 110 to 90bar. Increase in pump displacement from 16 LPM to 23 LPM results in rise in regeneration efficiency of the HRBS between2.6 to 16.7%. While increasing initial speed at braking from 20 to 35 KMPH, regeneration efficiency of the HRBS system rises by 48%. This is the maximum rise in regeneration efficiency while varying the initial braking speed.

Numerical and experimental analysis of dry contact in pad disc brake assembly

When driving in cities, due to intensive loads, the brake disc assembly aside of mechanical and thermal stresses. Thermal stresses are the main source of risk for the braking system. In the paper, a numerical thermo-mechanical analysis was performed using ANSYS software for brake disc assembly within a hydraulic braking system. In the numerical analysis the model coupled between disc and pad was considered. In the paper were determined the total deformations, the values of Von Misses stresses and the temperature variations within a certain braking interval. In the first modelling was considered a ventilated disc made of gray cast iron and brake pads made of semi metallic material. In the second modelling was considered the same brake disc and pads made of composite material with organic fibre. The simulation models will be validated by experimental determinations on a hydraulic braking plant. Both numerical simulation and experimental determinations were performed by considering ten successive brakes. The results were used to compare the values obtained from numerical and experimental temperatures in order to validate the considered models.

Control Allocation for Hybrid Braking Considering Dynamic Battery Behaviour

This work deals with the problem of maximizing energy recovery while optimizing braking capability of high-performance electric vehicles under given actuator constraints. A scalable, real-time capable concept using a complementary filter with an additional daisy chain for the control allocation between hydraulic brakes and electric motors is proposed. Furthermore, a model inversion approach that derives necessary battery limits while trying to decouple the wheel speed control loop from the protection loop of a modern battery management system is described. The hybrid braking control architecture is studied in simulation and validated in a prototype electric vehicle by highly dynamical driving manoeuvres.

Research on multi-mode regenerative braking energy recovery of electric vehicle with double rotor hub motor

In this study, a new type of double rotor hub motor is proposed. Then, its structure, the working principle as well as the regenerative braking energy recovery modes are described. In detail, three kinds of regenerative braking energy recovery modes, i.e., double motor regenerative braking mode, single inner motor regenerative braking mode and single outer motor regenerative braking mode, are introduced. The mathematical models of single wheel dynamics model and double rotor hub motor model are established. The three kinds of braking energy recovery modes are compared and the simulation results show that, by using the sliding mode control strategy, on the condition that the maximum braking energy recovery of the motor is satisfied, the hydraulic braking torque can make corresponding response according to the change of the regenerative braking torque of the motor. At the same time, antilock braking of the wheel is achieved.

Development of an automated hydraulic brake control system for testing aircraft turboshaft gas turbine engines

To absorb the power generated by a free turbine, hydraulic brake systems of various designs are used in ground tests of aircraft turboshaft gas turbine engines. Ground tests of aircraft turboshaft gas turbine engines with the use of such hydraulic brakes can result in emergency modes of automated engine control in the area of operation of a free turbine speed regulator. Mismatch between the hydraulic brake loading characteristics and the loading characteristics of the rotor driven by a free turbine of the engine is the main cause of emergency operation of automated control systems.The presented experimental loading characteristics of the hydraulic brake and the helicopter rotor show their significant difference in terms of gain. To eliminate this difference, a possibility of modeling dynamic parameters of rotors by simple automation means was considered. To solve this problem, a linear dynamic model and a block diagram of an automated hydraulic brake control system for ground testing of turboshaft gas turbine engines were elaborated. The law of regulation of the hydraulic brake loading was substantiated. A structurally dynamic diagram of the developed automated control system was presented and calculation formulas for determining the regulator parameters were given. Transient characteristics of the hydraulic brake unit without automation means and with the use of an automated loading control system were calculated. The presented calculation results have shown that the use of automation make it possible to fully emulate characteristics of the helicopter rotors

An intelligent braking system composed single-pedal and multi-objective optimization neural network braking control strategies for electric vehicle

The braking system is significant to improve the total energy efficiency and ensure driving security of electric vehicles. An intelligent braking system (IBS) composed single-pedal and multi-objective optimization neural network braking control strategies is proposed in this paper to improve the energy economy, braking stability and driving intelligence for electric vehicles. The braking operations of drivers are divided into two parts: (1) releasing the accelerator pedal and (2) stepping on brake pedal. In the first braking operation, a single-pedal regenerative braking control strategy (RBCS) of accelerator pedal based on adaptive fuzzy control algorithm is proposed to improve energy recovery and driving intelligence. Simulation results illustrate that the simulation velocities under the control of adaptive single-pedal RBCS can follow several standard test cycles (including US06, UDDS, LA92 and ECE) very well. The braking energy can be recovered effectively with a less usage of brake pedal. In the second braking operation, a neural network (NN) controller for the composite braking system (CBS) is proposed to optimize the energy economy and braking stability at the same time. The control effect is verified by simulation results under NEDC cycles. The hardware-in-loop (HIL) experiments of the IBS are also conducted in this paper. Compared with a parallel braking strategy used in EU260 electric vehicles, the energy economy of IBS is improved by 3.67% than EU260 in 3 NEDC cycles. IBS performs more closely to the I curve in a specific braking condition with a decreasing braking severity. The time ratio of hydraulic braking in IBS is 2.27% less than EU260 with an increasing driving intelligence.

Optimal Design and Analyses of T-shaped rotor Magnetorheological Brake

Magnetorheological (MR) brakes, belonging to the class of electromagnetic brakes, have a potential to replace conventional hydraulic brakes owing to reversible, rapidly controllable torque characteristics. In this study, T-shaped rotor MR brake was considered due to their higher braking torque capability and compactness compared to other configurations of brake. Optimal design of the brake was performed considering brake rotor radius, rotor thickness, flange length, casing thickness, coil height and coil width. Magnetostatic analyses were performed for different combinations of parameters of the brake dimensions to compute the magnetic flux density generated in the MR fluid region and the torque ratio and mass were calculated. The optimum dimensions of the brake were determined based on maximization of torque ratio and minimization of mass of the brake using multi-objective Genetic algorithm optimization technique. Further, magnetostatic analyses of the T-rotor brake with optimal dimensions were performed and torque characteristics were compared with those obtained for brake with simple disk rotor. It was concluded that T-rotor brake produces higher braking torque compared to simple disk rotor type MR brake for similar dimensions.

Energy efficiency of hydraulic regenerative braking for an automobile hydraulic hybrid propulsion method

ABSTRACTA hydraulic hybrid propulsion method with the hydraulic common pressure rail for automobiles is proposed. The hydraulic regenerative braking characteristics of the hydraulic hybrid propulsion method are investigated with simulation and experiment. The dynamic responses of the system in the hydraulic regenerative braking mode are studied. The results indicate that there is an obvious correlation between the hydraulic motor speed and the hydraulic transformer speed in both driving mode and hydraulic regenerative braking mode. In the hydraulic regenerative braking mode, a greater hydraulic transformer controlled angle makes a higher braking torque applied by the hydraulic motor. The hydraulic accumulator pressure is positively correlated with the hydraulic transformer controlled angle. The energy losses include the rolling resistance energy loss, the air resistance energy loss and the hydraulic energy loss. The hydraulic energy loss is in the majority. The proportions of the rolling resistance energy loss and the air resistance energy loss become higher when the average vehicle speed becomes larger during hydraulic regenerative braking.