Electromechanical Brake Research Articles

A Comparative Analysis of Brake-by-Wire Smart Actuators Using Optimization Strategies

Since the automotive industry is shifting towards electrification, brake-by-wire technologies are becoming more prevalent. However, there has been little research comparing and optimizing brake-by-wire actuators in terms of their energy expenditure and response time. This paper investigates the comparison of three different smart brake-by-wire actuators, Electro-Hydraulic Brakes (EHB), Electro-Mechanical Brakes (EMB), and Electronic Wedge Brakes (EWB), first by defining an objective metric and then using both linear and nonlinear optimization techniques. Modeling of the actuators is performed using the bond graph method. Then, the controllers are designed using a robust control strategy, Youla parameterization. After designing the controllers, two types of optimization are performed on the actuators. Optimizations are performed in two ways: 1. by linearizing the plants and optimizing using their transfer functions and 2. by nonlinear optimization of the plants in the closed-loop following a specific clamp force target. The objective metrics or the cost functions for these optimizations are chosen to be the energy usage of the plants during the closed-loop operation, maximum power requirement, and their dynamic responsiveness. Using this optimization framework, we can show a significant improvement in the energy usage of the actuators and slight improvements in their responsiveness. In the end, the actuators are compared in terms of their energy usage for sets of initial and optimized physical parameters.

Беспилотный измеритель коэффициента сцепления взлетно-посадочных полос

The paper describes an autonomous friction coefficient tester with an electromechanical braking device of the measuring wheel. Its structure is given and the computer vision system operation is described.

Enhanced Force Estimation for Electromechanical Brake Actuators in Transportation Vehicles

In transportation vehicles, the installation of force sensors for electromechanical brake systems causes cost issues and implementation difficulties. The elimination of the sensor is highly demanded. The main vulnerability of the existing force estimators is that the algorithms either rely on shifting characteristic curves or empirical data to determine the major quantities. Hence, they are less capable of dealing with initialization offset errors, fast-changing dynamics, and uncertainties. This article presents a novel super-twisting observer to accurately estimate the clamping force on the basis of a dynamic torque-balance model. In this observer, an extended state is defined on top of a super-twisting algorithm. The observer gains are computed through a smooth Lyapunov function to guarantee the fast convergence. It is experimentally validated that the observer enhances the performance required by the antilock braking systems in comparison with conventional methods.

Control System Design for Electromechanical Brake System Using Novel Clamping Force Model and Estimator

The electromechanical brake (EMB) is a key component of the brake-by-wire (BBW) system generating the clamping force between the brake pad and disk through an electric motor and mechanical transmission. Control of the clamping force has significant impact on the brake performance. In this paper, an EMB clamping force control system is developed that addresses several major challenges in the practical implementation. Firstly, a nonlinear EMB model including the DC motor, planetary gear set, ball screw, and clamping force model is built. In particular, a novel clamping force model is introduced based on a linear transform of two polynomial functions. For the control system design, a clamping force estimation algorithm is proposed that requires only the existing measurements of motor torque, angular speed, and position. The contact point of the brake pad and the disk is also estimated using an internal model controller and a Rauch–Tung–Striebel smoother. The tracking controller is based on the disturbance observer structure, with a PI feedback controller and a zero-phase error tracking feedforward controller. Furthermore, a unified architecture is proposed such that a smooth transition between gap closing and clamping force tracking is realized. Finally, the performance of the entire control system under various conditions is evaluated based on simulation.

Research on Anti-lock Braking System of Electro-mechanical Braking Vehicle Based on Feature Extraction

With the increase of vehicle speed, the increase of road traffic density and people’s higher requirements for vehicle safety, the Anti-lock Braking System (ABS) has become an important safety device on vehicles. It not only has the braking function of the common braking system, but also can prevent the wheels from locking. Automobile ABS is an important device that affects the safety of automobile braking system and driving safety. It can shorten braking distance and improve directional stability and operability during braking. Electro-mechanical braking control system adopts advanced electro-mechanical braking technology and is applied to automobile braking control system together with anti-lock braking system. Emb (electro-mechanical brake) uses electric energy as the energy source of the braking system, and uses the motor to drive the actuator to generate braking force, which responds quickly and can effectively improve the active safety of automobiles. In this paper, based on feature extraction algorithm, the brake pressure estimation method of EMB actuator is proposed, and the anti-lock braking control algorithm of automobile is analyzed.

Modeling and Simulation of an Electromechanical Brake System

The effect of brake pad wear on the electromechanical disc brake system response using MATLAB/Simulink software was investigated in this paper. The analysis of the pad wear involves building thermal model and electromechanical brake model, and calculating the required braking force at a constant and variable coefficient of friction between the pad and disc. A comparison between the electromechanical brake responses without wear and during wear at a constant and variable coefficient of friction was carried out. The results show that the coefficient of friction has a major role in calculating the required braking force, and cumulated wear during breaking. The required braking force starts higher in the case of using a variable coefficient of friction by about 0.06%. The variable coefficient of friction presents higher wear than the constant coefficient of friction by about 30%.

Braking performance oriented multi-objective optimal design of electro-mechanical brake parameters.

Excellent braking performance is the premise of safe driving, and improve the braking performance by upgrading structures and optimizing parameters of braking systems has become the pursuit of engineers. With the development of autonomous driving and intelligent connected vehicle, new structural schemes such as electro-mechanical brakes (EMBs) have become the future of vehicle braking systems. Meanwhile, many scholars have dedicated to the research on the parameters optimization of braking systems. While, most of the studies focus on reducing the brake size and weight, improving the brake responses by optimizing the parameters, almost not involving the braking performance, and the optimization variables are relatively single. On these foundations, a multi-objective optimal design of EMB parameters is proposed to enhance the vehicle's braking performance. Its objectives and constraints were defined based on relevant standards and regulations. Subsequently, the decision variables were set, and optimal math model was established. Furthermore, the co-simulation platform was constructed, and the optimal design and simulation analyses factoring in the crucial structural and control parameters were performed. The results confirmed that the maximum braking pressure response time of the EMB is decreased by approximately 0.3 s, the stopping distance (SD) of 90 km/h-0 is shortened by about 3.44 m. Moreover, the mean fully developed deceleration (MFDD) is increased by 0.002 g, and the lateral displacement of the body (LD) is reduced by about 0.037 m. Hence, the vehicle braking performance is improved.

An ultrasonic sensor based automatic braking system to mitigate driving exhaustion during traffic congestion

Traffic congestion has been the most tiresome encounter since the initiation of vehicle advancement. Many braking systems have been designed by researchers in previous studies, but this study is primarily focused on a braking system that is affordable to all because it is based on a simple Arduino-controlled system. Moreover, it is assistive on everyday traffic commutes rather than highway driving, which is relatively rare for normal drivers. As more and more vehicles crowd the roads, the more problematic it is becoming for the drivers, which is ultimately leading toward increment in the frontal car accidents. In this study, an electro-mechanical braking system has been deployed that assists the driver during the jam-packs by measuring the exact distance between the driven and forthcoming vehicle or any obstacle by applying the brakes without the driver pressing the brake pedal to ultimately bring the vehicle to a halt without any fear of vehicle collision. An ultrasonic sensor is used at the front bumper grille that measures the distance between the two closing vehicles. The total time to halt the vehicle has been calculated as 0.6 s, while the critical distance for the sensor has been set as 1-m. Furthermore, the stepper motor drivers are set at the maximum current output of 2.5 amps with a 12-volt battery connected in parallel to the motors. It is found that theoretical stopping time is in good agreement with the experimental stopping time to completely press the brake pedal and halt the car.

Fast calculation method of transient temperature rise of motor for electro-mechanical braking.

Electro-mechanical braking is a new braking mode of rail vehicles, which has the advantages of compact structure, fast response speed, and high precision. It is a new braking technology that conforms to the development trend of full electrification and full intelligence of rail transit brake devices. Due to the special power demand of the electro-mechanical braking device, the electro-mechanical braking motor has a short-time and intermittent working mechanism and is in the state of blocking during working, resulting in its high-temperature rise. Therefore, it is necessary to calculate the temperature rise of the motor quickly and accurately at the beginning of its design. To address this problem, based on the coupling calculation of the equivalent thermal circuit method and the equivalent magnetic circuit method, a fast temperature rise calculation method of the motor is proposed. Then, using the fast calculation method, the temperature rise of the electro-mechanical brake motor under different working periods and wind speed is calculated. By function fitting the calculated results, the motor temperature rise curve fitting function is obtained, which can accurately predict the temperature rise of the motor under different working conditions. It provides a theoretical basis for the use of electro-mechanical braking motor in different working conditions and also provides a reference for the design of the electro-mechanical braking motor.

Control of Electronic Mechanical Brake System on Automobile Electromechanical Brake

To verify the brake effect and the mechanism of exerting the brake of the electronic mechanical brake (EMB) system in the brake process of electronic vehicles, the working environment and function of each component of EMB are analysed based on the current relevant laws and regulations. Each component of EMB is calculated and selected. The mechanical relationship between the components of the EMB system are analysed, the preliminary EMB structure is designed, and the key parameters such as EMB brake pressure and EMB brake clearance elimination time are tested. Results show that the difference between the experimental value and theoretical value of the brake pressure test of the preliminary designed EMB structure aren’t large, and the brake clearance force increases with the increase of the locked-rotor voltage. When the voltage increases to 12V, the theoretical brake clearance force is 16510N and the experimental value is 15998N. During the EMB brake clearance elimination time test, the maximum speed of the brake block running at a constant speed during the elimination of brake clearance phase is 2.39mm/s, which is similar to the theoretical value Vmax=2mm/s. The experimental and theoretical motor brake speed is reduced to 88 rpm/min at 0.15s and at 0.13s. With all indicators considered, the EMB system can be used to control electromechanical brakes and provide certain guidance for its development.

Design and experimental study of electrical and mechanical brake for mine hoist

To meet the requirement of the braking response of the coal mine hoist, a new electromechanical braking technology for mine hoists is proposed, the principle of electromechanical braking of mine hoists is demonstrated, and the detailed parameters and braking performance of electromechanical brakes are given. Index, an electromechanical brake test platform with large load and high response is developed. Experiments show that the maximum positive pressure of the designed electromechanical brake reaches 33 KN, which meets the requirement of positive pressure of mine hoist. The braking error is less than 10 %, and the braking gap elimination time is less than 0.1 s. There is a linear relationship between motor current input and brake positive pressure output, with a slope of 4.17 and an intercept of 0.62. The screw displacement output and the brake pressure output have a cubic relationship, and the zero error is small. Through research, a new idea is provided for the development of electromechanical brakes for coal mine hoist.

Sliding-Mode Clamping Force Control of Electromechanical Brake System Based on Enhanced Reaching Law

The control of clamping force has a significant influence on the braking performance of low-floor trams. However, the load torque variations, strong nonlinearity and complex structure of electromechanical brake (EMB) systems present challenging the clamping force control issues. In this paper, an EMB system mathematical model is established. Then, an enhanced sliding-mode reaching law (ESMRL) is investigated to address these issues. In addition, novel gap distance elimination and adjustment strategies are proposed to improve the response quality and adjust the gap distance in a simple and low-cost way. Taking advantages of minimal chattering and short reaching times, the proposed ESMRL enhances the dynamic performance and tracking accuracy of the clamping force control. Finally, simulation and experimental results are offered to validate the effectiveness and superiority of the proposed control strategy.

Clamping force control of electro-mechanical brakes based on driver intentions.

Electro-mechanical brakes (EMBs) are the future of braking systems, particularly in commercial vehicles. Therefore, it is important to design a simple EMB scheme and establish its clamping force control strategy to satisfy the demands of commercial vehicle braking systems. This study proposes a pneumatic disc-brake-based EMB for an electric bus. Its working principle was established, and the system model was analyzed. Subsequently, the hidden Markov models (HMMs) of driver decelerate and brake intentions were built and recognized based on the analytic hierarchy process (AHP). Given the time-consuming behavior of the proposed EMB to eliminate brake clearance due to the leverage effect of the arm and motor performance limitation, a clamping force control strategy factoring in the driver intentions was developed to improve the response performance without changing the structure or size of the EMB. Furthermore, simulation analyses were performed using MATLAB/Simulink. The results confirmed that under the action of a step and 5 Hz triangular sawtooth signals, the clamping force output from the EMB corresponds well with the target signal. The clamping force gradually increases when approaching the target without overshoot and jitter during the process. The overall clamping force response time is decreased by approximately 0.25 s under the driver emergency brake than the conventional control method. Hence, the response performance of the EMB is improved.

Coupled rigid-flexible modelling and dynamic characteristic analysis of electromechanical brake (EMB) units on trains

The electromechanical braking is a novel braking mode, which is the development direction of the electrification and intelligent train braking system. In this paper, a coupled-rigid-flexible model of the EMB unit is developed, and dynamic characteristics of the EMB unit are analysed based on the model. Firstly, assumed mode method is used to describe the axial and torsional vibration of the screw in nut-screw assembly, and lumped mass method is used to describe motions of other components in the EMB unit. Secondly, the EMB unit model is established and simulated in Matlab/Simulink software based on electro-mechanical and rigid-flexible coupling characteristics. Then the model parameters are calibrated by experiment. Finally, the simulated model is studied to analyse the influence of various factors on the dynamic characteristics of the EMB unit. The results indicate that an increment in viscous damping flats the fluctuation of the pushout force. The maximal pushout force decreases and the changing trend of force is different along with the rotational structure damping increases. The flexible vibration of the screw results in higher pushout force, meanwhile the fluctuation of the force is greater with higher braking instruction current value. When the ratio of the screw length to the screw cross-sectional diameter is 30, the pushout force varies along with the friction pairs wear under vibration. The study can provide references for structure design, control design and fault diagnosis of EMB units.

An electro-mechanical braking energy recovery system based on coil springs for energy saving applications in electric vehicles

Regenerative braking system is a promising energy recovery mechanism to achieve energy saving in EVs (electric vehicles). This paper focuses on a novel mechanical and electrical dual-pathway braking energy recovery system (BERS) based on coil springs for energy saving applications in EVs. With the aims of maximizing energy recovery efficiency, mechanical and electrical recovery strategies are respectively employed under two different brake situations of inching braking and emergency braking. This system mainly consists of three parts, including the mechanical module, electrical module and control module. The mechanical module utilizes coil springs to store the kinetic energy in the form of elastic potential energy which can be utilized to provide a part of the starting torque for EVs. The electrical module enables recovery of the braking energy into the vehicle battery. The control module controls the mechanical module and the electrical module to work coordinately to select an appropriate energy recovery pathway under different braking modes. A full-size prototype, manufactured and based on this design, is introduced. Simulations and experiments of the proposed regenerative braking system are conducted to verify the system. Auxiliary starting torque of 12.7 N m, maximum voltage of 3.5 V and total energy recovery efficiencies of 0.53 can be obtained, verifying that the proposed braking energy recovery system is effective and beneficial for vehicle energy savings.

Simulation and Experimental Study of a New Electromechanical Brake with Automatic Wear Adjustment Function

This paper presents a novel electromechanical brake (EMB) with automatic wear adjustment function, which has been ignored in most previous studies. With the aim of investigating the parameter characteristics of the EMB system and analyzing the proposed function, the mathematical models of the DC motor, motor friction, worm drive, ball screw and load are established in MATLAB/Simulink. The differences between the simulation and the experiment under step, triangular wave, square wave and sinusoidal input signals are discussed. The parameter characteristics of clamping force-motor current and clamping force-ball screw displacement are obtained, which also verifies that the established model is correct. The results demonstrate that the automatic wear adjustment function of the new EMB could guarantee that the brake stroke and response time remain consistent across each braking manoeuvre.

Robust force control for brake-by-wire actuators via scenario optimization

Clamping force control in Electro Mechanical Brakes (EMBs) is a challenging task, mainly due to the nonlinear dynamics of the system and the uncertainty affecting its physical parameters. In this paper, a robust tuning of a PID control loop for an EMB is proposed. First, a control-relevant linear model of the system is derived. Then, the optimal parameters of the controller are tuned by solving a convex pole-placement problem and probabilistic robustness guarantees are provided according to the scenario theory. Finally, the performance of the proposed strategy is assessed on a complex nonlinear simulator of the EMB dynamics, and compared with the state of the art approach for robust control of EMBs.

Modelling and Validation of An Electronic Wedge Brake System with Realistic Quarter Car Model for Anti-Lock Braking System Design

With the advancement in battery and electronics technologies, soon Electric Vehicles (EV) will replace traditional vehicles as they are more efficient and environment friendly. This will require replacement of all mechanical systems in vehicles with their electrical counterparts. This study focuses on electromechanical brakes (EMB) as replacement of hydraulics brakes. Particularly a type of EMB known as Electronic Wedge Brake (EWB) which uses wedges to create self reinforcing braking force and consume less power than other EMBs. Detailed mathematical model of an EWB system is presented which provides braking force and torque to the disk brake. A Quarter Car Model (QCM) with realistic parameter values and aerodynamic deceleration is modelled to validate the EWB system. The system is validated for different road conditions and anti-lock braking system (ABS) is demonstrated for snowy road using a single PID controller. The results validate the brake and car model and a need for cascaded control strategy to implement ABS is established.

Evaluation of Efficient Operation for Electromechanical Brake Using Maximum Torque per Ampere Control

This paper deals with efficient operation method for the electromechanical brake (EMB). A three-phase interior permanent magnet synchronous motor (IPMSM) is applied to the EMB operation. A current controller, speed controller, and position controller based on proportional-integral (PI) control are used to drive the IPMSM. Maximum torque per ampere (MTPA) control is applied to the current controller to perform efficient control. For MTPA control, the angle β is calculated from total input current, and the synchronous frame d–q axis current reference is determined by the angle β. The IPMSM is designed and analyzed with finite element analysis (FEA) software and current control is simulated by Matlab/Simulink using a motor model designed by FEA software. The simulation results were verified to compare with experimental results that are input current and clamping force of caliper. In addition, the experimental results showed that the energy consumption is reduced by MTPA.

Accurate State Estimation for Electro-Mechanical Brake Systems

Electro-mechanical brake (EMB) system is an electric motor based braking force generation module, and it requires various sensors such as motor position, motor current and clamping force sensor for stable vehicle deceleration control. Because fault in these sensors can lead to degradation of the system performance, system monitoring is essential. To build a model based state estimator for the braking system, there are some requirements: the mathematical model presenting the nonlinearity and disturbance of the real system, fast response time and the accurate estimation. To solve this problem, this paper proposes a new EMB model which clamping force term is divided into the linear and nonlinear compensation part, and Kalman filter algorithm is applied to design the state estimator. The proposed model is simple and linear, and Kalman filter algorithm is robust to system noise and guarantees the fast computation time. Additionally, the braking direction aware and contact point aware clamping force estimation techniques are introduced, and they help to improve the accuracy of the state estimation. Lastly, the proposed approach is verified through experiments on the EMB test bench.