Showing papers on "Dynamic braking published in 2013"

Precise Braking Torque Control for Attitude Control Flywheel With Small Inductance Brushless DC Motor

Abstract: In this paper, a newly designed braking torque control scheme with improved toque estimation and control characteristics in a small inductance brushless DC motor is presented. The motor torque is estimated according to the back electromotive force (EMF) shape function that is fitted by neural network and corrected by temperature. Upon this, a hybrid braking torque control structure that combines dynamic braking and plug braking is proposed for the smooth and continuous braking torque. These two braking modes operate, respectively, in the relatively high- and low-speed ranges. During dynamic braking, a predictive torque control method is proposed to suppress the torque fluctuation that is induced by the supplying voltage namely back EMF descent. During plug braking, an effective torque ripple reduction method is designed to weaken the large torque ripple which is caused by high winding voltage, low winding impedance, and three-phase inverter modulation. In addition, different pulse width modulation patterns and the most suitable operating conditions for each braking mode have been studied. Finally, experimental results are presented to demonstrate the validity and effectiveness of the proposed braking torque control scheme.

Methods and systems for extending regenerative braking

Abstract: Systems and methods for improving operation of a hybrid vehicle are presented. In one example, an electrical load may be automatically activated to consume electrical energy produced during driveline braking so that driveline braking may be extended. The electrical load may be a windscreen heater or other device.

Monitoring autonomous vehicle braking

Abstract: Instructions are provided to a vehicle braking mechanism for autonomous operation of the braking mechanism. At least one first parameter is retrieved for governing control of the braking mechanism. The first parameter is applied to operation of the braking mechanism. Data is collected relating to operation of the vehicle. At least one second parameter is determined for governing control of the braking mechanism.

Energy-Regenerative Braking Control of Electric Vehicles Using Three-Phase Brushless Direct-Current Motors

Abstract: Regenerative braking provides an effective way of extending the driving range of battery powered electric vehicles (EVs). This paper analyzes the equivalent power circuit and operation principles of an EV using regenerative braking control technology. During the braking period, the switching sequence of the power converter is controlled to inverse the output torque of the three-phase brushless direct-current (DC) motor, so that the braking energy can be returned to the battery. Compared with the presented methods, this technology can achieve several goals: energy recovery, electric braking, ultra-quiet braking and extending the driving range. Merits and drawbacks of different braking control strategy are further elaborated. State-space model of the EVs under energy-regenerative braking operation is established, considering that parameter variations are unavoidable due to temperature change, measured error, un-modeled dynamics, external disturbance and time-varying system parameters, a sliding mode robust controller (SMRC) is designed and implemented. Phase current and DC-link voltage are selected as the state variables, respectively. The corresponding control law is also provided. The proposed control scheme is compared with a conventional proportional-integral (PI) controller. A laboratory EV for experiment is setup to verify the proposed scheme. Experimental results show that the drive range of EVs can be improved about 17% using the proposed controller with energy-regeneration control.

Power stage precharging and dynamic braking apparatus for multilevel inverter

Abstract: Precharging and dynamic braking circuits are presented for multilevel inverter power stages of a power converter with a shared resistor connected to charge a DC bus capacitor with current from the rectifier circuit in a first operating mode and connected in parallel with the capacitor to dissipate power in a dynamic braking mode.

Cooperative Control of Regenerative Braking and Antilock Braking for a Hybrid Electric Vehicle

Abstract: A new cooperative braking control strategy (CBCS) is proposed for a parallel hybrid electric vehicle (HEV) with both a regenerative braking system and an antilock braking system (ABS) to achieve improved braking performance and energy regeneration. The braking system of the vehicle is based on a new method of HEV braking torque distribution that makes the antilock braking system work together with the regenerative braking system harmoniously. In the cooperative braking control strategy, a sliding mode controller (SMC) for ABS is designed to maintain the wheel slip within an optimal range by adjusting the hydraulic braking torque continuously; to reduce the chattering in SMC, a boundary-layer method with moderate tuning of a saturation function is also investigated; based on the wheel slip ratio, battery state of charge (SOC), and the motor speed, a fuzzy logic control strategy (FLC) is applied to adjust the regenerative braking torque dynamically. In order to evaluate the performance of the cooperative braking control strategy, the braking system model of a hybrid electric vehicle is built in MATLAB/SIMULINK. It is found from the simulation that the cooperative braking control strategy suggested in this paper provides satisfactory braking performance, passenger comfort, and high regenerative efficiency.

Adaptive neuro-fuzzy wheel slip control

Abstract: Due to complex and nonlinear dynamics of a braking process and complexity in the tire–road interaction, the control of automotive braking systems performance simultaneously with the wheel slip represents a challenging problem. The non-optimal wheel slip level during braking, causing inability to achieve the desired tire–road friction force strongly influences the braking distance. In addition, steerability and maneuverability of the vehicle could be disturbed. In this paper, an active neuro-fuzzy approach has been developed for improving the wheel slip control in the longitudinal direction of the commercial vehicle. The dynamic neural network has been used for prediction and an adaptive control of the brake actuation pressure, during each braking cycle, according to the identified maximum adhesion coefficient between the wheel and road surface. The brake actuation pressure was dynamically adjusted on the level that provides the optimal level of the longitudinal wheel slip vs. the brake pressure selected by driver, the current vehicle speed, the brake interface temperature, vehicle load conditions, and the current value of longitudinal wheel slip. Thus the dynamic neural network model operates (learn, generalize and predict) on-line during each braking cycle, fuzzy logic has been integrated with the neural model as a support to the neural controller control actions in the case when prediction error of the dynamic neural model reached the predefined value. The hybrid control approach presented here provided intelligent dynamic model – based control of the brake actuation pressure in order to keep the longitudinal wheel slip on the optimum level during a braking cycle.

Vehicle Motion Control Apparatus, and Vehicle Motion Control Method

Abstract: A vehicle motion control apparatus that the travel stability of a vehicle can be maintained by appropriately controlling the regenerative braking force in accordance with the wheel slip state or the road surface friction coefficient, and that the amount of regeneration of regenerative energy by the electric motor 13 can be ensured under various situations which may range from gradual braking to rapid braking is provided. A braking/driving force allocation unit of the vehicle motion control apparatus allocates braking/driving force to a front wheel 7FL, 7FR and a rear wheel 7RL, 7RR on the basis of braking/driving force required for the vehicle 50 and decreases the braking/driving force for one of the front wheel 7FL, 7FR and the rear wheel 7RL, 7RR for which the braking/driving force is generated by the electric motor 13 in response to a decrease in the ratio of braking/driving force to a slip ratio of at least one of the front wheel 7FL, 7FR and the rear wheel 7RL, 7RR.

Simulation-Based Genetic Algorithm towards an Energy-Efficient Railway Traffic Control

Abstract: The real-time traffic control has an important impact on the efficiency of the energy utilization in the modern railway network. This study is aimed to develop an energy-efficient railway traffic control solution for any specified railway. In other words, it is expected to define suitable driving profiles for all the trains running within a specified period through the targeted network with an objective to minimize their total energy consumption. How to optimize the train synchronization so as to benefit from the energy regenerated by electronic braking is also considered in this study. A method based on genetic algorithm and empirical single train driving strategies is developed for this objective. Six monomode strategies and one multimode strategy are tested and compared with the four scenarios extracted from the Belgian railway system. The results obtained by simulation show that the multi-mode control strategy overcomes the mono-mode control strategies with regard to global energy consumption, while there is no firm relation between the utilization rate of energy regenerated by dynamic braking operations and the reduction of total energy consumption.

Motor drive apparatus equipped with dynamic braking control unit

Abstract: A motor drive apparatus includes an inverter which has an upper and lower arms each provided with a plurality of semiconductor switching devices and free-wheeling diodes connected in reverse parallel with respective ones of the plurality of semiconductor switching devices, wherein the semiconductor switching devices are controlled on and off to convert DC to AC, a short-circuiting unit which includes a selector switch between motor phase windings of a synchronous motor, the selector switch being opened and closed under the control of a command, and a dynamic braking control unit which, upon reception of a dynamic braking start command, performs control so as to turn on all of the semiconductor switching devices provided in either one of the upper and lower arms and to turn off all of the semiconductor switching devices provided in the other arm, and thereafter controls the short-circuiting unit so that the selector switch is closed.

Designing and testing an advanced pneumatic braking system for heavy vehicles

Abstract: Heavy goods vehicles exhibit poor braking performance in emergency situations when compared to other vehicles. Part of the problem is caused by sluggish pneumatic brake actuators, which limit the control bandwidth of their antilock braking systems. In addition, heuristic control algorithms are used that do not achieve the maximum braking force throughout the stop. In this article, a novel braking system is introduced for pneumatically braked heavy goods vehicles. The conventional brake actuators are improved by placing high-bandwidth, binary-actuated valves directly on the brake chambers. A made-for-purpose valve is described. It achieves a switching delay of 3–4 ms in tests, which is an order of magnitude faster than solenoids in conventional anti-lock braking systems. The heuristic braking control algorithms are replaced with a wheel slip regulator based on sliding mode control. The combined actuator and slip controller are shown to reduce stopping distances on smooth and rough, high friction (μ = 0.9) surfaces by 10% and 27% respectively in hardware-in-the-loop tests compared with conventional ABS. On smooth and rough, low friction (μ = 0.2) surfaces, stopping distances are reduced by 23% and 25%, respectively. Moreover, the overall air reservoir size required on a heavy goods vehicle is governed by its air usage during an anti-lock braking stop on a low friction, smooth surface. The 37% reduction in air usage observed in hardware-in-the-loop tests on this surface therefore represents the potential reduction in reservoir size that could be achieved by the new system.

Vehicle dynamics with brake hysteresis

Abstract: This paper studies hysteresis of vehicle brakes and its influence on the vehicle dynamics. The experimental investigation clearly shows the non-linear and asymmetric characteristics of hysteresis of the disk brakes in passenger cars. A computational model of the brake mechanism with hysteretic elements, based on the Bouc–Wen method, is developed and verified with experimental data. Using the developed model, the influence of hysteresis on the vehicle dynamics during straight-line braking with an anti-lock braking system is analysed. It is also observed that the variations in the hysteresis parameters have important influences on the main vehicle brake characteristics such as the stopping (brake) distance, the time of braking and the average deceleration. A comparative analysis of the simulation results is also given for braking with zero hysteresis or with hysteresis represented as a signal delay and linear function.

A new braking force distribution strategy for electric vehicle based on regenerative braking strength continuity

Abstract: Regenerative braking was the process of converting the kinetic energy and potential energy, which were stored in the vehicle body when vehicle braked or went downhill, into electrical energy and storing it into battery. The problem on how to distribute braking forces of front wheel and rear wheel for electric vehicles with four-wheel drive was more complex than that for electric vehicles with front-wheel drive or rear-wheel drive. In this work, the frictional braking forces distribution curve of front wheel and rear wheel is determined by optimizing the braking force distribution curve of hydraulic proportional-adjustable valve, and then the safety brake range is obtained correspondingly. A new braking force distribution strategy based on regenerative braking strength continuity is proposed to solve the braking force distribution problem for electric vehicles with four-wheel drive. Highway fuel economy test (HWFET) driving condition is used to provide the speed signals, the braking force equations of front wheel and rear wheel are expressed with linear equations. The feasibility, effectiveness, and practicality of the new braking force distribution strategy based on regenerative braking strength continuity are verified by regenerative braking strength simulation curve and braking force distribution simulation curves of front wheel and rear wheel. The proposed strategy is simple in structure, easy to be implemented and worthy being spread.

Conceptual designs of hybrid locomotives for application as heavy haul trains on typical track lines

Abstract: A computer simulation technique has been used to study and evaluate the potential for the application of hybrid locomotives to heavy haul operations on two typical track routes in Australia. The study envisages typical pit-to-port operations with large altitude changes. The train energy usage and the energy created by dynamic braking are analysed based on the simulation results. It is shown that the locomotives operate at an average power that is much less than full power. It is found that there is potential for hybrid heavy haul locomotive applications. Suggested methods and concept designs are proposed. Sizing of the energy storage system when it contained batteries, super-capacitors and flywheels was carried out for comparison purposes. The merits and problems with each concept are discussed.

Digital Sliding Mode Control of Anti-Lock Braking System

Abstract: The control of anti-lock braking system is a great challenge, because of the nonlinear and complex characteristics of braking dynamics, unknown parameters of vehicle environment and sy ...

A Study on Control Strategy of Regenerative Braking in the Hydraulic Hybrid Vehicle Based on ECE Regulations

Abstract: This paper establishes a mathematic model of composite braking in the hydraulic hybrid vehicle and analyzes the constraint condition of parallel regenerative braking control algorithm. Based on regenerative braking system character and ECE (Economic Commission of Europe) regulations, it introduces the control strategy of regenerative braking in parallel hydraulic hybrid vehicle (PHHV). Finally, the paper establishes the backward simulation model of the hydraulic hybrid vehicle in Matlab/simulink and makes a simulation analysis of the control strategy of regenerative braking. The results show that this strategy can equip the hydraulic hybrid vehicle with strong brake energy recovery power in typical urban drive state.

Dynamic braking of induction motor - Analysis of conventional methods and an efficient multistage braking model

Abstract: In this paper, a detailed analysis is made on capacitor self excitation and DC injection methods of dynamic braking of induction motor through MATLAB/SIMULINK simulations. The effectiveness of these conventional dynamic braking methods is carefully analyzed while changing various parameters. The speed range and time duration for which these methods are the most effective is carefully observed during changing load conditions. The effects of changing capacitor values and DC injection voltage levels on the effective speed range have been studied and the time durations in which these methods are most effective are also analyzed. Using the analysis data obtained, the parameters of a reliable fast multistage dynamic braking model are arrived upon for its best possible performance. The performance of this model, which efficiently dissipates the kinetic energy of the motor in a very short duration of time, is checked through simulations.

Investigation of regenerative and Anti-lock Braking interaction

Abstract: The use of a regenerative braking mode can reduce overall vehicle energy usage for most of the most common drive cycles. However, a number of technical issues restrict the use of regenerative braking for all possible braking situations. These issues are concerned with two key limitations. The first is related to physical limitations of the applied regenerative braking system, e.g. Electric Motor (E-Motor) power limits; energy storage device capacity and vehicle load transfer etc. The second limitation results from the potentially detrimental interaction between regenerative braking and the Anti-locking Braking System (ABS). The first type of limitation can, to some extent, be alleviated by suitable choice of hardware and, as a consequence, will not be discussed further in this paper. The second type of limitation concerns the regenerative braking strategies during an ABS event. Some of the regenerative braking strategies designed and investigated within the Low Carbon Vehicle Technology Project (LCVTP) will be described and analyzed in this paper. A comparison of competing strategies is made and conclusions are drawn together with suggestions for further research. The work has been progressed as a part of a major research programme; namely the LCVTP, which has been conducted within an extensive industrial and academic partnership, mutually funded by the European Regional Development Found and Advantage West Midlands.

The simulation of a novel regenerative braking strategy on front axle for an unaltered mechanical braking system of a conventional vehicle converted into a hybrid vehicle

Abstract: Regenerative braking is one of the most important features of a hybrid vehicle Currently used regenerative braking systems add a considerable cost to the vehicle due to the electronics involved The author presents here a novel method for implementing a regenerative brake strategy without changing the mechanical brake system, ie, without adding complex electronic systems like ABS, of a low cost conventional vehicle which is converted to a low-cost HEV (hybrid electric vehicle) for front axle applications The electric braking force is additional to the mechanical braking force applied by friction brakes under normal conditions In a previous study, a similar strategy was discussed but for application on the rear axle only This strategy pertains to the regenerative brake force being applied on the front axle of a rear wheel drive vehicle The strategy is simulated over urban drivecycles and results are compared with NEDC drivecycle The results show a potential of 30% of brake energy recuperation with the proposed strategy The study also illustrates the relevance of the strategy to high traffic volume markets with low vehicle speeds

Electromechanical braking system architecture

Abstract: The invention relates to a braking system architecture for an aircraft having wheels 1 braked by means of respective brakes 2 , each brake having a plurality of electromechanical actuators 3 a, 3 b , the braking system having controllers 8 a, 8 b for distributing electric power Ps to the actuators 3 a, 3 b in response to a braking setpoint, each controller 8 a, 8 b being associated with some of the actuators of any given brake. According to the invention, each controller 8 a, 8 b has an input Ev for receiving information about the rotary speed of the wheel 1 braked by the actuators associated with said controller, the controller including processor means 13 for modulating the power transmitted to the actuators as a function of the speed of rotation of the wheel in order to provide anti-skid protection.

Control apparatus and method for regenerative braking of eco-friendly vehicle

Abstract: A variable control apparatus and method of the amount of regenerative braking of a vehicle using a paddle shift are provided. The method includes sensing, by a controller, positive (+) and negative (−) shifting in a manual mode based on a signal from a shift-operating unit during regenerative braking with a drive (D) gear engaged while the vehicle travels. A regenerative braking torque map that corresponds to a selected gear is selected based on the signal from the shift-operating unit. In addition, regenerative braking of a driving motor is adjusted based on the torque value calculated from the selected regenerative braking torque map.

Method of decelerating a vehicle with regenerative and friction braking

Abstract: A method of decelerating a vehicle equipped with both regenerative powertrain braking from a motor/generator and friction braking from fluid pumped through a brake circuit. A deceleration demand is received, and regenerative braking torque is ramped up in response to the deceleration demand. The brake circuit is pre-charged during the ramping up of regenerative braking torque. Pre-charging the brake circuit includes pumping fluid to at least one wheel cylinder braking device to reduce the required pump speed and resulting noise for any subsequent braking demand on the brake circuit. The pump is actuated to operate at a predetermined speed that maintains noise and vibration below predetermined levels.

Optimal Regenerative Braking Control for Permanent Magnet Synchronous Motors in Electric Vehicles

Abstract: The permanent magnet synchronous motors(PMSM) is widely adopted for traction motor in the electric vehicles(EV) with the advantage of high efficiency and high torque density.Field oriented control(FOC) is appropriate for PMSM and the maximum efficiency control can be achieved.In this paper,the principle for electric braking control of PMSM under FOC was studied.Based on this,the optimal regenerative braking control strategy for EV was obtained with the model of the electric drive system(including PMSM,inverter and battery),which was significant for the economical operation of EV.In the existing electrical and mechanical coupling braking methods of EV,the parallel and the series braking control strategies were compared.The results showed that the optimal regenerative braking was achieved in the series braking control strategy and a good regenerative braking could be obtained by adjusting the free travel of mechanical brake appropriately with the parallel braking control strategy.

Antiskid Braking Control with On/Off Valves for Aircraft Applications

Abstract: Traditional pressure servo valves used in hydraulic aircraft antiskid braking system are sensitive to contamination and require a high maintenance cost. This paper proposes an on/off-valve-based antiskid braking system with simple structure and high resistance to contamination for aircraft applications. It can improve the system reliability and reduce maintenance cost. An aircraft longitudinal motion model and a hydraulic antiskid braking system model with on/off valves are formulated. Based on these models, a switched controller with delay compensation is developed for an aircraft antiskid braking system using on/off valves. It features a switching surface derived through backstepping to govern the switching action of the valves and a pressure predictor to compensate the delay caused by response time of valves and brake lines. In addition, an approximation brake line model and a tire friction force observer are included in the controller to estimate the brake pressure and friction force, respectively. Th...

An adaptive braking system and method

Abstract: An adaptive braking system for a motor vehicle is described, the system comprising an assisted braking system and a controller arranged to determine, in response to one or more driving condition parameters and in advance of a brake application,the braking assistance to be provided. Braking assistance is defined by a function which maps a brake actuation parameter to be applied from a detected brake pedal actuation parameter. The or each driving condition parameter includes an environmental condition parameter. The controller may also adjust the braking assistance in response to one or more braking response signals.

System and method for monitoring braking effort

Abstract: A method (e.g., for monitoring a braking system of a vehicle system) includes monitoring fluid pressures of a braking system and modeled braking efforts of the braking system in a vehicle system traveling along a route, identifying one or more time periods at least one of before a brake event of the braking system or after the brake event, calculating residual forces exerted on the vehicle system during the one or more time periods, and determining at least one of an estimated braking effort of the braking system or an estimated propagation rate at which the estimated braking effort is applied by the braking system using the residual forces that are calculated.

Dynamic Braking Control for Accurate Train Braking Distance Estimation under Different Operating Conditions

Abstract: The application of Model Reference Adaptive Control (MRAC) for train dynamic braking is investigated in order to control dynamic braking forces while remaining within the allowable adhesion and coupler forces. This control method can accurately determine the train braking distance. One of the critical factors in Positive Train Control (PTC) is accurately estimating train braking distance under different operating conditions. Accurate estimation of the braking distance will allow trains to be spaced closer together, with reasonable confidence that they will stop without causing a collision. This study develops a dynamic model of a train consist based on a multibody formulation of railcars, trucks (bogies), and suspensions. The study includes the derivation of the mathematical model and the results of a numerical study in Matlab. A threerailcar model is used for performing a parametric study to evaluate how various elements will affect the train stopping distance from an initial speed. Parameters that can be varied in the model include initial train speed, railcar weight, wheel-rail interface condition, and dynamic braking force. Other parameters included in the model are aerodynamic drag forces and air brake forces. An MRAC system is developed to control the amount of current through traction motors under various wheel/rail adhesion conditions while braking. Minimizing the braking distance of a train requires the dynamic braking forces to be maximized within the available wheel/rail adhesion. Excessively large dynamic braking can cause wheel lockup that can damage the wheels and rail. Excessive braking forces can also cause large buff loads at the couplers. For DC traction motors, an MRAC system is used to control the current supplied to the traction motors. This motor current is directly proportional to the dynamic braking force. In addition, the MRAC system is also used to control the train speed by controlling the synchronous speed of the AC traction motors. The goal of both control systems for DC and AC traction motors is to apply maximum available dynamic braking while avoiding wheel lockup and high coupler forces. The results of the study indicate that the MRAC system significantly improves braking distance while maintaining better wheel/rail adhesion and coupler dynamics during braking. Furthermore, according to this study, the braking distance can be accurately estimated when MRAC is used. The robustness of the MRAC system with respect to different parameters is investigated, and the results show an acceptable robust response behavior.

Brake system and method for generating a braking force

Abstract: The brake system (1) has two brake circuits with two pressure generating units, which are supplied with energy from two energy sources. A single error in the brake circuits is detected, where the faulty brake circuit is deactivated and a functional brake circuit is activated. A braking effect generated by the former pressure generating unit is greater than or equal to a predetermined operating braking effect, where another braking effect generated by the latter pressure generating unit is greater than or equal to the predetermined operating braking effect. An independent claim is included for a method for generating a braking force in a vehicle, particularly in a partial, high or fully automatically operated vehicle.