Electro-mechanical Braking System Research Articles

Electromechanical braking systems and control technology: A survey and practice

Electromechanical braking systems and control technology: A survey and practice

Electro-Mechanical Brake System Architectural Design and Analysis Based on Functional Safety of Vehicles

Electro-mechanical brake (EMB) systems have garnered significant attention due to their distributed architecture. However, their signals from the brake pedal to the wheel-end actuators (WEAs) are transmitted electrically, meaning that any fault in EMB systems can severely impair the braking performance of vehicles. Consequently, the functional safety issues of EMB systems are the primary limitation of their widespread adoption. In response, this study first introduced the typical architectures of EMB and evaluated the automotive safety integrity level (ASIL) that must be achieved. Based on this, an EMB system architecture that satisfies functional safety standards was proposed. To accurately analyze the main factors affecting the probabilistic metric for hardware failures (PMHF) of the architecture, the failure rate of WEAs is further discussed. Specifically, a Markov chain was employed to define the operating states of the WEA matrix. The availability of each operating state was assessed based on the fault-tolerant control strategy. Finally, the failure rates of critical EMB parts, particularly the WEA matrix, were calculated. The results indicate that the unavailability of the WEA matrix is 9.244 × 10−3 FIT. Furthermore, the PMHFs of the EMB system for each safety goal are 6.14 FIT, 5.89 FIT, and 6.03 FIT, respectively, satisfying the ASIL-D requirements.

Design and Research of an Elevator Electric Brake Release Device with a Safety Detection Function

Abstract In response to the issues and defects associated with the current method of using electrical devices to open brakes for emergency rescue, a new elevator electric brake release device applicable to any elevator employing an electromechanical braking system has been designed. This device mainly consists of a car data collection unit and a brake release control unit, utilizing the STM32F103C8T6 microcontroller as the control core for elevator emergency rescue operations. The car data collection unit is responsible for gathering and transmitting data on the car’s operational state and position, while the brake release control unit evaluates the conditions for emergency rescue operations and performs real-time analysis, storage, and display of the collected data. It also decides whether to output a brake release signal. Experimental results show that when conditions for rescue operations are met, the electric brake release device can ensure the safe operation of the elevator; when abnormalities are detected, it outputs a signal to stop operations, alongside fault alarms and status displays.

Comparison between traditional vacuum booster and electro-mechanical braking system

The Electro-Mechanical Braking System (EMB) is an innovation in the energy supply and transmission of the brake drive mechanism. It provides braking energy with a motor and transmits the driver's braking intention with an electrical signal, and the actuator is still a conventional brake. The automotive electronic mechanical system is in line with the three major themes of safety, energy saving, and environmental protection, and is the development direction of the future brake system. Its research is still in the experimental stage, and there is still some distance from the product launch. Therefore, by comparing the structure and principle of the traditional vacuum booster and the Electro-Mechanical brake system, this paper analyzes their respective advantages and disadvantages, and finally points out that under the current background, the research and development of the Electro-Mechanical brake system is still immature, because its structure is more compact and complex, it is more difficult to conduct simulation, and it still needs to increase research and development investment.

Variable Universe Fuzzy-Proportional-Integral-Differential-Based Braking Force Control of Electro-Mechanical Brakes for Mine Underground Electric Trackless Rubber-Tired Vehicles.

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.

Wheel slip ratio control considering time delay characteristic for electro-mechanical braking system

Electro-mechanical braking (EMB) system is a novel brake-by-wire (BBW) system which is the development direction of the electrification and intelligent vehicle braking system. However, as the EMB contains a mechanical transmission mechanism, there is an inevitable time delay in the braking process, which will cause problems of the wheel slip ratio control. To address this issue, this paper proposes a novel wheel slip ratio control system based on a hierarchical control framework, comprising a slip ratio control layer and a clamping force control layer. Firstly, an EMB actuator model considering the stiffness and damping characteristics of the ball screw is constructed and the correspondence between the model and the EMB object is verified. Subsequently, a model-based compensate active disturbance rejection control (MCADRC) algorithm based on the EMB actuator model is designed to compensate the uncertainty of the EMB and improve the tracking accuracy of the clamping force. Furthermore, the influence of time delay on slip ratio control is analyzed and a slip ratio controller considering time delay characteristic is developed to improve the slip ratio control quality. Finally, the HiL test results show that the proposed controller can effectively reduce the jitter of slip ratio by 1.2% and improve the response speed of slip ratio control 7.8%, which prove the real-time and effectiveness of the controller.

Coordinated control strategy of electro-mechanical composite braking for four-wheel drive electric vehicles

Regenerative braking energy recovery technology is critical for electric vehicles, which can significantly improve vehicle mileage. In addition, the regenerative braking system is often used with the friction braking system to provide vehicle braking force. This paper presents an electro-mechanical compound brake control strategy for four-wheel drive electric vehicles equipped with an electro-mechanical braking system. Firstly, the configuration of a four-wheel drive electric vehicle with an electro-mechanical braking system is introduced. The mathematical models of the driving motor, battery, and electro-mechanical braking are established. Secondly, a new control method is introduced by optimizing torque allocation based on maximum energy recovery with considering battery limits and a cooperative control method of the electro-mechanical composite braking system. It can be ensured that the braking energy recovery capability and braking comfort. Finally, simulation results indicate that the introduced control strategy can increase the braking recovered energy by 3% and 4%, respectively, under NEDC and WLTC conditions, compared to the ideal braking force distribution strategy. The introduced control method can effectively decrease the braking impact and ensure braking comfort in the coordination control section.

Enhanced Estimation of Clamping-Force for Automotive EMB Actuators Using a Switching Extended State Observer

The automotive intelligence and electrification require the braking system to cooperate with the controller to achieve regenerative and active braking functions. Hence, the range and driving safety of the electric vehicles are improved. Electromechanical Brake (EMB) systems completely abandon the fluid and hydraulic elements and replace the traditional hydraulic braking system with a wire harness and electromechanical parts. The braking torque adjustment is achieved entirely by controlling the four-wheel EMBs. At present, reliability and fault tolerance are the key technical issues associated with EMBs. To eliminate the need of any clamping-force sensor due to its vulnerability and high cost, in this paper, a switching extended state observer (SESO) is presented to provide rapid force estimation with higher precision. The substrates of the internal linear and nonlinear structures have been unified into a single form by using an equivalent gain method. The SESO is effective to detect the initial contact between the braking disk and pad by estimating the load torque. It is experimentally verified that the developed force sensorless control strategy is accurate and superior to the existing techniques.

Simulation of screw size effect on performance of electro-mechanical braking system

Electro-mechanical brakes (EMB) are promising alternatives to conventional braking systems, as they are eco-friendly and have lower maintenance requirements. Currently, researchers and automotive manufacturers are interested in developing the performance of EMB systems for implementation in commercial vehicles. Current studies are either conducted experimentally and/ or modeled using mathematical based simulation models using different vehicles kinematic and dynamic models. These models are time-consuming, and expensive in case of experimental implementation. This paper presents a simple and easy-to-construct simulation model using MATLAB Simulink Graphical user interface (GUI) without using conventional mathematical modelling techniques. The presented simulation model studies the effect of the lead screw size on performance of EMB in terms of the generated clamping force and system response time. The accuracy and reliability of the proposed model were statistically verified using ANOVA. In addition, its performance was verified by comparing its results with the same input data used in previously validated experimental and mathematical-based simulation models from the literature review. The proposed model can be used to improve the performance of EMB systems and facilitate comparisons among different EMB designs.

Research on motor rotation anomaly detection based on improved VMD algorithm

PurposeThe electromechanical brake system is leading the latest development trend in railway braking technology. The tolerance stack-up generated during the assembly and production process catalyzes the slight geometric dimensioning and tolerancing between the motor stator and rotor inside the electromechanical cylinder. The tolerance leads to imprecise brake control, so it is necessary to diagnose the fault of the motor in the fully assembled electromechanical brake system. This paper aims to present improved variational mode decomposition (VMD) algorithm, which endeavors to elucidate and push the boundaries of mechanical synchronicity problems within the realm of the electromechanical brake system.Design/methodology/approachThe VMD algorithm plays a pivotal role in the preliminary phase, employing mode decomposition techniques to decompose the motor speed signals. Afterward, the error energy algorithm precision is utilized to extract abnormal features, leveraging the practical intrinsic mode functions, eliminating extraneous noise and enhancing the signal’s fidelity. This refined signal then becomes the basis for fault analysis. In the analytical step, the cepstrum is employed to calculate the formant and envelope of the reconstructed signal. By scrutinizing the formant and envelope, the fault point within the electromechanical brake system is precisely identified, contributing to a sophisticated and accurate fault diagnosis.FindingsThis paper innovatively uses the VMD algorithm for the modal decomposition of electromechanical brake (EMB) motor speed signals and combines it with the error energy algorithm to achieve abnormal feature extraction. The signal is reconstructed according to the effective intrinsic mode functions (IMFS) component of removing noise, and the formant and envelope are calculated by cepstrum to locate the fault point. Experiments show that the empirical mode decomposition (EMD) algorithm can effectively decompose the original speed signal. After feature extraction, signal enhancement and fault identification, the motor mechanical fault point can be accurately located. This fault diagnosis method is an effective fault diagnosis algorithm suitable for EMB systems.Originality/valueBy using this improved VMD algorithm, the electromechanical brake system can precisely identify the rotational anomaly of the motor. This method can offer an online diagnosis analysis function during operation and contribute to an automated factory inspection strategy while parts are assembled. Compared with the conventional motor diagnosis method, this improved VMD algorithm can eliminate the need for additional acceleration sensors and save hardware costs. Moreover, the accumulation of online detection functions helps improve the reliability of train electromechanical braking systems.

Slip ratio control based on adaptive fuzzy sliding mode for vehicle with an electromechanical brake system

The development of vehicle intelligence has driven the evolution of brake-by-wire systems, with electromechanical braking (EMB) emerging as a crucial development in intelligent vehicle braking. To enhance the braking safety of EMB-equipped vehicles, this paper proposes a slip ratio control method based on adaptive fuzzy sliding mode control (AFSMC) to more effectively achieve wheel slip ratio tracking during braking. The approach involves establishing the mathematical model of the planetary gear-type EMB system and the vehicle’s longitudinal dynamics model. Additionally, a hierarchical collaborative control strategy is introduced, where the bottom layer employs the EMB clamping force control algorithm based on cascaded proportional-integral (PI), and the top layer integrates AFSMC to regulate the slip ratio. The simulation results, validated using the joint simulation platform of Simulink and Carsim under various conditions, illustrate that the AFSMC, compared to the conventional sliding mode controller (SMC), attains more precise control of wheel slip ratio while mitigating the chattering phenomenon. These findings suggest the potential of AFSMC for practical engineering applications.

Study on multi-closed loop control of electro-mechanical braking for electric vehicles based on clamping force

In order to improve the clamping force control accuracy of electro-mechanical braking system of electric vehicles, a multi-closed loop control strategy of electro-mechanical braking based on clamping force is proposed. A detailed EMB mathematical model is established. The sliding mode speed controller and improved fuzzy PID clamping force controller are designed, and the joint simulation model of the speed the clamping force controller is established, and simulation experiments are used to verify the effectiveness of the control strategy. Comparative analysis of three simulation conditions, the maximum adjustment time of the proposed control strategy is 0.254 s and the maximum overshoot is 0.45%. The results of research show that the control strategy designed in this paper can quickly and stably reach the target value of clamping force, has a strong anti-interference capability, has some reference value in the electric vehicle braking control.

Clamping Force Control Strategy of Electro-Mechanical Brake System Using VUF-PID Controller

Clamping force control is one of the key technologies in the algorithm design and implementation of electro-mechanical braking system, whose control effects directly affect the vehicle braking performance and safety performance. In order to improve the clamping force control performance of electro-mechanical braking (EMB) system, an EMB clamping force control method based on Variable universe adaptive fuzzy PID (VUF-PID) controller is proposed, and stretching factors are added to the fuzzy PID control. According to the operation of the controlled object, the fuzzy theory domain can be adjusted in real time to keep the system in the proper parameter value and improve the adaptive ability of the system. The response characteristics and effectiveness of clamping force under step braking condition, gear switching braking condition and sine braking condition are verified by simulation experiments using MATLAB/Simulink. The results show that the proposed VUF-PID control method has strong tracking characteristics and stability characteristics, and meet the braking requirements under different braking conditions.

Electro-mechanical braking system spindle unbalance axis trajectory purification and feedback method

The brake disc spindle of the electromechanical braking system will be accompanied by vibration unbalanced fault during the rotation operation, which will affect the braking performance of the brake system. In view of this phenomenon, based on the ensemble empirical mode decomposition algorithm and related energy operation theory, an offline purification program for the unbalanced axial trajectory of the spindle of electromechanical braking system are designed. Meanwhile, an online braking control feedback procedure for the axial trajectory are designed based on Cspace controller. Based on the designed program and braking theory, an experimental bench of the electro-mechanical braking system was set up, and experiments were conducted on the purification of the axial trajectory and the braking of the fault feedback respectively. The results show that the EEMD algorithm and the related energy operation theory can purify the unbalanced axial trajectory of the brake discs of the braking system and draw an ideal axial trajectory fault map; meanwhile, the experimental data of the fault feedback braking shows that the time required from the unbalanced fault monitoring to the completion of the braking process of the braking system is 1.278 s, which can effectively achieve the purpose of emergency braking in case of sudden failure. Through research, a new idea is provided for the development of electro-mechanical braking system fault detection and feedback.

A Review of Electro-Mechanical Brake (EMB) System: Structure, Control and Application

With the development of automobile electrification and intelligence, the demand for electro-mechanical braking (EMB) systems is increasing rapidly. This paper reviews the development status of the EMB actuator on the basis of extensive patent and literature research. By analyzing the basic structure of the EMB actuator, this paper decomposes the actuator into five modules: service brake module, parking brake module, brake clearance compensation module, quick-return module and sensor module. On the basis of basic structure, the estimation algorithm for indirect clamping force control and the direct clamping force control algorithm of the actuator are summarized. In addition, the requirements of the EMB system for intelligent vehicles and its typical architecture are analyzed, and the preliminary application of the EMB system in intelligent driving is summarized.

Study on Braking Energy Recovery Control Strategy for Four-Axle Battery Electric Heavy-Duty Trucks

Regenerative braking can extend the driving range and reduce PM emissions from abrasion for battery electric heavy-duty trucks (BETs). The composite braking control strategy including torque distribution and dynamic coordinated control for the four-axle BET equipped with the electromechanical braking system is studied. A segmented torque distribution strategy is proposed to maximize energy recovery while ensuring braking stability. The simulation results reveal that the strategy shows better comprehensive braking performance than the two benchmark strategies, and the energy recovery rate in different load states under CHTC-D is above 40%. The proposed coordinated control strategy takes advantage of regenerative braking’s rapid response and precise control to compensate for torque deviations caused by the hysteresis of friction braking. For two common braking mode transition conditions, regenerative braking torque correction and advance of the mode switching timing are adopted to enable the motor to obtain the torque compensation ability. This method leads to a slight loss of braking energy, and the maximum torque deviation during the mode switching process is suppressed to less than 1.4 kN·m, and the jerk and braking distance is reduced accordingly, which is of great importance in improving driving comfort and braking safety.

Reliability evaluation of electromechanical braking system of mine hoist based on fault tree analysis and Bayesian network

Electromechanical braking system is the key way to improve the braking response ability of mine hoist. At present, the reliability research of electromechanical braking system is less. In order to further analyze and improve the reliability of electro-mechanical braking system, this paper adopts the reliability analysis method of electro-mechanical braking system based on fault tree and Bayesian network. Firstly, the fault tree of the electro-mechanical braking system is established, and then the fault tree is transformed into a Bayesian network, and the posterior probability, probability importance and key importance of each root node are inversely deduced. The diagnosis results show that the ball screw is the weakest link of the electro-mechanical braking system. Then the static simulation and fatigue life simulation of the ball screw are carried out for optimization, and the optimal model of the ball screw is determined. Finally, the electro-mechanical brake installed with the optimized ball screw is tested and analyzed. After the reliable performance test of the electro-mechanical brake, it is finally determined that the braking effect of the optimized electro-mechanical brake is stable.

An adaptive backstepping nonsingular fast terminal sliding-mode control for the electromechanical brake system with backlash nonlinearity compensation

With the operation of low-floor trams, unavoidable nonlinear factors such as backlash and parameter perturbation are present in electromechanical brake (EMB) systems. This results in poor clamping force tracking performance and challenges the operational safety of trams. Thus, an adaptive nonsingular fast terminal sliding-mode control algorithm is proposed to address this thorny problem. Firstly, a differentiable function approximates the backlash nonlinearity. Then, a dynamic mathematical model for an EMB system with backlash nonlinearity and parameter perturbation is established. Based on the backstepping control principle, this paper divides the system into three subsystems, and the nonsingular fast terminal sliding-mode control (NFTSMC) algorithm is adopted to design the controller of each subsystem. Notably, the NFTSMC algorithm can solve the parameters perturbation problem by the large switching gains, which may cause the chattering phenomenon. This paper utilizes the adaptive law to establish an adaptive NFTSMC algorithm to improve this phenomenon. Furthermore, the global asymptotic stability of the system is analyzed using Lyapunov theory. Finally, experimental results clearly validate the effectiveness and superiorities of the proposed control algorithm.

Optimal systemic combined design and control of an automated wind energy conversion system

In this paper, is presented a design and control toll of electromechanical braking system dedicated to wind energy conversion chain. The braking system makes it possible to apply pressure strength at the level of the rotating shaft near to the propeller of the wind turbine. This pressure force is transformed into a dry friction force via the mechanical part of the braking system consisting of a piece of brake lining and steel of the rotating shaft of the propeller. A program of dimensioning by the analytical method of a permanent magnet linear motor structure is developed. The interactions between this program and the braking system control algorithm are taken into account. The integration of the global model under the Matlab-Simulink simulation environment allows full validation of the presented study.

Optimal Slip Ratio Tracking Integral Sliding Mode Control for an EMB System Based on Convolutional Neural Network Online Road Surface Identification

As the main branch of the brake-by-wire system, the electro-mechanical brake (EMB) system is the future direction of vehicle brake systems. In order to enhance the vehicle braking effect and improve driver safety, a convolutional neural network (CNN) online road surface identification algorithm and an optimal slip ratio tracking integral sliding mode controller (ISMC) combined EMB braking control strategy is proposed in this paper. Firstly, according to the quarter-vehicle model and Burckhardt tire model, the vehicle braking control theory based on the optimal slip ratio is analyzed. Secondly, using the VGG-16 CNN method, an online road surface identification algorithm is proposed. Through a comparative study under the same dataset conditions, it is verified that the VGG-16 method has a higher identification accuracy rate than the SVM method. In order to further improve the generalization ability of VGG-16 CNN image identification, data enhancement is performed on the road surface image data training set, including image flipping, clipping, and adjusting sensitivity. Then, combined with the EMB system model, an exponential approach law method-based ISMC is designed to achieve the optimal slip ratio tracking control of the vehicle braking process. Finally, MATLAB/Simulink software is used to verify the correctness and effectiveness of the proposed strategy and shows that the strategy of real-time identifying road surface conditions through vision can make the optimal slip ratio of vehicle braking control reasonably adjusted, so as to ensure that the adhesion coefficient of wheel braking always reaches the peak value, and finally achieves the effect of rapid braking.