Study on regenerative braking system, considerations of design, safety and associated effects

This paper presents a model-based fault detection method for an electrohydraulic braking system with cooperative regenerative braking management. The regenerative braking system can save energy and improve endurance in electric vehicles. However, failure of the regenerative system may result in the system being unable to fully convert the recovered energy into stored electrical energy, with a large portion of the energy being dissipated as heat. Meanwhile, the motor braking torque output is limited, and the range of battery state of charge is affected. In this paper, a Carsim/Simulink co-simulation was developed to model the operating conditions and failure modes of the regenerative braking system in an electric vehicle. A three-stage dynamic equation was derived to model the piston movement in the wheel cylinder of the electrohydraulic braking system. A vector control using coordinate transformation was developed for the permanent magnet synchronous motor to control the current and torque. Since various system components have been built, the advantage of model-based methods can perform predictive maintenance compared with the current corrective and preventive maintenance. Therefore, this paper proposed a three-layer systematic model (torque distribution layer, execution layer, and actuation layer) of electric vehicle regenerative braking system to detect and diagnose various fault conditions. Various parameters were compared with the normal braking mode in order to provide systematic guidance on fault detection.

<div class="section abstract"><div class="htmlview paragraph">A novel type of regenerative braking system for electric vehicles is proposed in this paper. Four pressure-difference-limit valves, two relief valves and two brake pedal simulators, are added to the layout of a conventional four-channel hydraulic modulator. The cooperation of relief valves and hydraulic pumps provides a stabilized high-pressure source. Pressure-difference-limit valves ensure that the pressure in each wheel cylinder can be modulated separately at a high precision. Besides, the functions of anti-lock braking system and electronic stability program are integrated in this regenerative braking system. The models of regenerative braking controller and vehicle dynamics are built in MATLAB/Simulink. Hydraulic brake model is built in AMESim through a parameterized and modularized method. Meanwhile, the control strategy of hydraulic brake modulation and brake force distribution are designed. Simulations are conducted via co-simulation interface between MATLAB and AMESim under scenarios of typical braking and ECE driving cycle. Simulation results show that regenerative and hydraulic braking forces are coordinated well during typical braking process, verifying the feasibility and effectiveness of the models built and strategies proposed. Under an ECE driving cycle, the proposed RBS can recover more than 75% of the total recoverable braking energy, which lengthen the vehicle’s driving range by more than 24%.</div></div>

- Regenerative braking systems play a vital role in improving the energy efficiency of modern electric and hybrid vehicles by recovering kinetic energy during deceleration. This project focuses on the design and development of a regenerative braking system that converts the kinetic energy of a moving vehicle into electrical energy, which is otherwise dissipated as heat in conventional braking systems. An electric motor is utilized to operate in dual modes, functioning as a drive motor during propulsion and as a generator during braking. When braking is applied, the motor generates electrical energy from wheel rotation and transfers it to an energy storage unit such as a battery or capacitor through power electronic converters. An electronic control unit ensures smooth transition between driving and braking modes while maintaining effective deceleration and system safety. The integration of regenerative braking with conventional friction brakes provides reliable stopping performance under all operating conditions. The developed system enhances overall energy utilization, reduces mechanical brake wear, and extends the operational range of electric vehicles. This study demonstrates the potential of regenerative braking technology to contribute significantly to sustainable transportation and efficient energy management in automotive and electromechanical applications. Key Words: Regenerative Braking System, Energy Recovery, Electric Motor Generator, Energy Storage System, Power Electronics, Electric Vehicles, Sustainable Transportation

Electric vehicles (EVs) have the advantage of using both regenerative braking and mechanical braking to produce the necessary braking torque. Currently, vehicles use Anti-lock Braking Systems (ABS) which provide intermittent braking torque to the vehicle and thereby prevents skidding or slipping of the vehicle by ensuring pure rolling of the wheels. Regenerative braking on the other hand generates the necessary braking torque by converting the kinetic energy of the vehicle to electrical energy via the motor(s). To coordinate both braking systems, the conventional method involves the use of crisp logic controllers that depend on lookup tables containing the data about various aspects of the vehicle such as battery state of charge (SoC), brake pedal input etc., to enable co-operative control of both systems. This paper presents a combined implementation of both braking systems in electric vehicles using separate fuzzy controllers for both ABS and regenerative braking. The control scheme is implemented such that when regenerative braking is not capable of providing enough braking torque, braking will be one by ABS. Two fuzzy logic controllers have been used, one to implement regenerative braking and the other to implement mechanical braking via ABS. If such a control algorithm is used, the driver will not have to manually adjust the level of regenerative braking in the vehicle and such an approach ensures that the braking process of an EV is smooth, safe and efficient. It also reduces the wear and tear of the brake pads thereby extending their life and reducing the cost of maintenance and by extension the total cost of ownership of the vehicle. The results demonstrate that the controllers for both ABS and regenerative braking can coordinate efficiently and reliably to produce proper and safe braking of the vehicle.

The regenerative braking system of electric vehicles can not only achieve the task of braking but also recover the braking energy. However, due to the lack of in-depth analysis of the energy loss mechanism in electric braking, the energy cannot be fully recovered. In this study, the energy recovery problem of regenerative braking using the independent front axle and rear axle motor drive system is investigated. The accurate motor model is established, and various losses are analyzed. Based on the principle of minimum losses, the motor control strategy is designed. Furthermore, the power flow characteristics in electric braking are analyzed, and the optimal continuously variable transmission (CVT) speed ratio under different working conditions is obtained through optimization. To understand the potential of dual-motor energy recovery, a regenerative braking control strategy is proposed by optimizing the dynamic distribution coefficient of the dual-electric mechanism and considering the restrictions of regulations and the I curve. The simulation results under typical operating conditions and the New York City Cycle (NYCC) proposed conditions indicate that the improved strategy has higher joint efficiency. The energy recovery rate of the proposed strategy is increased by 1.18% in comparison with the typical braking strategy.

Dry Tree Semisubmersibles (DTS), with the capability of supporting surface wellheads and allowing drilling and completion through direct vertical access risers, have attracted intense interest from the oil and gas industry. A wet tree deep draft semisubmersible has been carefully reconfigured considering the balance between the overall floater configuration and the tensioner stroke for a harsh environment application. A large amount of simulation efforts have been performed for the optimization of the integrated hull/deck/mooring/riser system. Recently, a basin model test was also successfully completed and further demonstrated its technical feasibility. The paper presents the overall design of a Top-Tensioned Riser (TTR) system for a DTS application focusing on the complexity of the DTS-TTR interface including ram style tensioning system, riser conductor and riser top assembly design with keel joint, etc. Due to the heavy weight of the TTR system in the ultra-deep water application, the riser top sections are subject to high reaction loads with the DTS in severe environments. The riser system faces the challenge to have a feasible and economic top assembly design. In this paper, an engineered riser conductor pipe is introduced to interface the riser top assembly with hull. The riser conductor pipe, which spans from deck to keel, is integrated with riser top assembly and the tensioner system design. The riser conductor protects the riser in the splash zone and prevents the high reaction loads directly transferring from hull to riser, thus reducing the riser keel joint and tension joint size. The feasibility and performance of the TTR system are demonstrated through the static and dynamic analyses. Pipe-in-pipe (PIP) contact model is employed in the simulation to ensure the dynamic interaction loads between riser and riser conductor are captured. The TTR overall system design consideration for the DTS application is discussed.

Applications of pedagogical agent (PA) systems incorporating animated characters in school settings have mainly addressed students at an individual level. However, how these systems could be used and designed for supporting teachers while taking advantage of artificial intelligence (AI) technology is an open question. Therefore, we carried out a focus group to understand what teachers would expect and need from such a system at a classroom level. Our focus group protocol sought to discover design and practical considerations in four dimensions. 1) System design considerations, where teachers expect the system to incorporate speech recognition and to “learn” from them while doing their practice. 2) System collaboration, teachers wanted support in their pedagogy by considering students’ achievement profiles, and by finding and sorting learning material as needed. 3) PA role in the classroom, we identified the following roles: annotator, scaffolder, peacekeeper, and substitute. 4) PA ethical considerations, teachers perceive PA as a possible replacement threat and controversial opinions on the use and meaning making of this technology. We discuss our findings and present future research directions to develop a PA that could empower teachers with AI pedagogy in the classroom, hence, indirectly supporting learning.KeywordsPedagogical agentClassroom level technologyArtificial intelligence pedagogyFocus groupEducational technology

Modifying the design of an existing system to meet the needs of a new task is a common activity in mechatronic system development. Often engineers seek to meet requirements for the new task via control design changes alone, but in many cases new requirements are impossible to meet using control design only; physical system design modifications must be considered. Plant-Limited Co-Design (PLCD) is a design methodology for meeting new requirements at minimum cost through limited physical system (plant) design changes in concert with control system redesign. The most influential plant changes are identified to narrow the set of candidate plant changes. PLCD provides quantitative evidence to support strategic plant design modification decisions, including tradeoff analyses of redesign cost and requirement violation. In this article the design of a counterbalanced robotic manipulator is used to illustrate successful PLCD application. A baseline system design is obtained that exploits synergy between manipulator passive dynamics and control to minimize energy consumption for a specific pick-and-place task. The baseline design cannot meet requirements for a second pick-and-place task through control design changes alone. A limited set of plant design changes is identified using sensitivity analysis, and the PLCD result meets the new requirements at a cost significantly less than complete system redesign.

The characteristics of electro-hydraulic braking systems have a direct influence on the fuel consumption, emissions, brake safety, and ride comfort of hybrid electric vehicles. In order to realize efficient energy recovery for ensuring braking safety and considering that the existing electro-hydraulic braking pressure control systems have control complexity disadvantages and functional limitations, this study considers the front and rear dual-motor-driven hybrid electric vehicle as the prototype and based on antilock brake system (ABS) hardware, proposes a new braking pressure coordinated control system with electro-hydraulic braking function and developed a corresponding control strategy in order to realize efficient energy recovery and ensure braking safety, while considering the disadvantages of control complexity and functional limitations of existing electro-hydraulic system. The system satisfies the pressure coordinated control requirements of conventional braking, regenerative braking, and ABS braking. The vehicle dynamics model based on braking control strategy and pressure coordinated control system is established, and thereafter, the performance simulation of the vehicle-based pressure coordinated control system under typical braking conditions is carried out to validate the performance of the proposed system and control strategy. The simulation results show that the braking energy recovery rates under three different conditions—variable braking intensity, constant braking intensity and integrated braking model—are 66%, 55% and 47%. The battery state of charge (SOC) recovery rates are 0.37%, 0.31% and 0.36%. This proves that the motor can recover the reduced energy of the vehicle during braking and provide an appropriate braking force. It realizes the ABS control function and has good dynamic response and braking pressure control accuracy. The simulation results illustrate the effectiveness and feasibility of the program which lays the foundation for further design and optimization of the new regenerative braking system.

This research focuses on the coordinated control of Electronic Stability Control (ESC) and Regenerative Braking System (RBS) for Parallel Hydraulic Hybrid Commercial Vehicles (PHHCV). The proposed control architecture consists of a top-level module with braking torque coordination, a middle-level module with privilege allocation between ESC and RBS and a low-level module with actuator coordination between air brake and hydraulic brake actuators.The proposed coordinated control aims at eliminating potential conflict on actuators of air brake and hydraulic brake systems and achieving maximum fuel economy while maintaining vehicle stability. PHHCV model and its actuator models have been established including both ESC and RBS system models. A coordinated control of ESC and RBS systems under proposed control architecture has been developed. Simulation has been conducted and the results demonstrates that the proposed method is valid and effective in achieving the design objectives.

In automobiles, Regenerative Braking (RB) / Acceleration Assist (AA) System captures a portion of the Kinetic Energy (KE) dissipated during braking and stores it in a reusable form to assist the subsequent acceleration of the vehicle. This improves the energy efficiency and reduces vehicle emissions. Electric hybrid cars employing regenerative braking systems are popular, but they are expensive and cannot capture energy at low speeds. Heavy trucks employ Hydraulic Regenerative Braking, which uses a hydraulic pump to pressurize hydraulic oil and stores the energy in a high pressure accumulator for reuse. They are heavy, bulky and expensive to be used in Light Motor Vehicles (LMVs). Hence there is a need for a low cost alternative to capture energy at low speeds. In an unconventional and unique attempt, we employ fluid power (Pneumatics) to build a Parallel RB/AA prototype for LMVs. Modeling, design, development and fabrication of a Parallel Pneumatic drive train with Regenerative Braking and Acceleration Assist (PPRB/AA) system has been attempted. Physical models were built and validated through simulation and experiments. A functional prototype of RB/AA system has been successfully built, mounted on a Go-kart and tested. Results show that even at very low velocities, energy lost during braking can be captured, stored and reused gainfully. Hence Parallel Pneumatic RB/AA system is a green and feasible alternative for LMVs operating at low urban velocities.

A regenerative braking system, which could restore kinetic energy and potential energy to a battery or any other forms of power during braking, is a special system for electric and hybrid electric vehicles. However, the large current produced by the generator during braking would affect battery performance and shorten battery life. A hybrid-power system is an excellent energy storage system, in which an ultra-capacitor bank and a battery pack are connected together through a DC/DC power converter. And the ultra-capacitor in this system can store instantaneous large currents quickly, which is able to protect the battery from large currents. The application advantages of the hybrid-power system are analyzed in this paper, as well as a series control strategy for regenerative braking based on it. In order to verify the feasibility of the strategy, a braking force distribution model, which contains one S-Function, between mechanical and regenerative braking is built in MATLAB/Simulink by taking into account the ultra-capacitor voltage, the motor regenerative braking ability and other factors. Simulation results suggest that the ultra-capacitor is able to restore the regenerative energy very quickly, which will improve starting and acceleration performance, extend driving range, and increase fuel economy.

With the development of the global automotive industry, environmental pollution and driving safety have been major problems. This paper focuses on a novel integrated cooperative antilock braking system (ABS) controller, which is used for antilock regenerative braking systems (ARBS) and antilock mechanical braking systems (AMBS) for hybrid electric vehicles (HEV) driving on different road surfaces. An intelligent tire system is utilized to detect varying road surfaces to obtain friction information and optimal operation slip ratio. In addition, the HEV eight‐degree‐of‐freedom dynamics model is developed for ABS control, which includes the LuGre tire model. Adaptive backstepping and finite state machine controllers are explored to maintain optimal wheel slip and regenerate energy, based on wheel slip, battery state of charge (SOC), motor capability torque, and vehicle velocity, and to develop the switching rules of regenerative and mechanical braking systems. In order to evaluate the performance of regenerative and mechanical braking systems on harvesting energy and driving safety, the HEV and LuGre dynamic tire models are developed in MATLAB SIMULINK /SimDriveline. The estimation results of different road surfaces and slip controller effects are tested via the experiments and simulations, finding good braking performances and high regenerative efficiency in different maneuvers.

Hybrid Electric Vehicle (HEV) is the most advance technology in automobile industries but long drive range in HEV is still a problem due to limited battery life. Regenerative braking system used in HEV to give backup power in deceleration mode which not only make HEV to drive longer but also increase the battery life cycle by charging of ultra-capacitor. Many researches have been done for increase the life cycle of battery by improvement in regenerative braking system where regenerated energy not fully returned to battery due to power losses are experienced in between such as losses in the motor armature and switching. In proposed system, improved regenerative braking system introduced which is simple, efficient due to less power losses in between BLDC motor and ESS without using of buck or boost system to minimized the losses. In regenerative braking mode, energy can be boosted by using of motor induction in winding by using H-bridge switches technic in inverter and transfer energy to ESS with minimum losses. These switches controlled by PWM through fuzzy logic controller. In resultant, battery working time and life will improve.

The electric vehicle’s overall efficiency can be augmented through the implementation of the regenerative braking system (RBS), which serves to extend the drive range. This paper explores a method for further increasing said range by implementing a roof‐mounted photovoltaic (PV) system in conjunction with RBS, resulting in an impressive 25.14% increase to the vehicle’s driving distance. The roof‐mounted PV and regenerative braking work together to charge the dual battery pack present within the vehicle, following a specific sequence as dictated by its controller. Maximum energy is extracted from the PV module via employment of a particle swarm optimization (PSO)‐based maximum power point tracking (MPPT) algorithm, while propulsion is provided through utilization of a brushless direct current (BLDC) motor driven by reduced switch voltage source inverter (VSI). The BLDC motor itself is controlled utilizing field‐oriented control (FoC), with hybrid ANN‐PID and Fuzzy‐PID (HAP‐FUP) controllers employed at the outer loop; furthermore, HAP‐FUP controller performance was compared favorably against other top controllers such as model predictive controller (MPC), sliding mode controller (SMC), and conventional PID controller, ultimately demonstrating superior performance when it comes to reducing rise time and settling time of vehicle speed.