Showing papers on "Dynamic braking published in 2011"

Adaptive Vehicle Speed Control With Input Injections for Longitudinal Motion Independent Road Frictional Condition Estimation

Abstract: This paper presents a novel real-time tire-road friction coefficient estimation method that is independent of vehicle longitudinal motion for ground vehicles with separable control of the front and rear wheels. The tire-road friction coefficient information is of critical importance for vehicle dynamic control systems and intelligent autonomous vehicle applications. In this paper, the vehicle longitudinal-motion-independent tire-road friction coefficient estimation method consists of three main components: 1) an observer to estimate the internal state of a dynamic LuGre tire model; 2) an adaptive control law with a parameter projection mechanism to track the desired vehicle longitudinal motion in the presence of tire-road friction coefficient uncertainties and actively injected braking excitation signals; and 3) a recursive least square estimator that is independent of the control law, to estimate the tire-road friction coefficient in real time. Simulation results based on a high-fidelity CarSim full-vehicle model show that the system can reliably estimate the tire-road friction coefficient independent of vehicle longitudinal motion.

Vehicle brake control system

Abstract: A vehicle brake control system has a braking detector and a braking controller. The braking detector determines whether a braking operation in a vehicle is within an initial braking stage based on a control condition of a frictional braking system. The braking controller performs initial braking stage control during the initial braking stage by controlling a regenerative braking system to provide a limited braking torque and the frictional braking system to provide a supplemental braking torque, the combination of which provides a target braking torque. The braking controller performs subsequent braking control when the initial braking stage ends to provide an increased regenerative braking torque and a lower supplemental braking torque as the target braking torque.

Vehicle and method for controlling regenerative braking

Abstract: A vehicle and a method for controlling regenerative braking may utilize the maximum available regenerative braking torque for some time during a braking event. As the vehicle speed and/or powertrain torque decreases, the regenerative braking torque is controlled to deviate from the maximum. The point at which the regenerative braking torque deviates from the maximum is chosen based on the level of vehicle deceleration. The regenerative braking torque is then smoothly blended out until it reaches zero. The regenerative braking torque is brought to zero when the vehicle speed is very low, thereby eliminating the inefficiencies associated with operating a motor at a very low speed.

Motion control system of vehicle

Abstract: Vehicular motion control system comprising controller that independently controls driving force and/or braking force of each of four wheels and a turning direction sensor that senses a turning direction, and with an acceleration/deceleration command generator that generates an acceleration/deceleration command based upon a sensed steering angle and sensed vehicle speed and a driving force/braking force distributor that determines the distribution of driving force or driving torque and/or braking force or braking torque of each wheel, and driving force/braking force distributor determines based upon the acceleration/deceleration command and the turning direction so that more driving force or more driving torque and/or more braking force or more braking torque are/is distributed to the inside front wheel in turning than the outside front wheel in turning and more driving force or more driving torque and/or more braking force or more braking torque are/is distributed to the outside rear wheel.

Vehicle braking system

Abstract: A vehicle braking system includes an electric motor, an operating amount detector, a brake assist controller, a first braking device and a second braking device. The electric motor drives a driving wheel via a reduction ratio setting device. The first braking device makes the electric motor generate a first braking power under regenerative control. The second braking device generates a second braking power by actuating an actuator with an operating fluid to be pressurized through a hydraulic pressure source. When an initiation condition for a brake assist control is met, the reduction ratio setting device sets a reduction ratio so as to reduce the first braking power and then suspends a change in the reduction ratio, and the first braking device generates the first braking power as well as the second braking device generates the second braking power to produce a target braking power.

Lane centering fail-safe control using differential braking

Abstract: Method, system and non-transitory computer-readable medium for fail-safe performance of a lane centering system. An electrical power steering (EPS) system of a vehicle is monitored for a failure and operation of the lane centering system is switched to a differential braking controller to output differential braking commands to a differential breaking system upon determining that a failure of the EPS system has occurred, where the output braking commands direct the differential braking system to apply force a brake for a wheel of vehicle, such by the applied braking force the vehicle follows a desired path determined for a lane centering operation.

Electric vehicle regenerative braking system

Abstract: A method and system for braking a vehicle are disclosed. The vehicle has at least one of an electronic stability control system and an antilock brake system. The vehicle may also include a regenerative brake adapted to apply a regenerative braking torque to slow the vehicle. The vehicle may further include a pressure sensor adapted to sense pressure in a hydraulic brake line. The pressure sensor may be a component of the at least one of the electronic stability control system and the antilock brake system. The vehicle may also include a controller adapted to control the regenerative braking torque of the regenerative brake based on at least the sensed pressure.

Modeling and System Identification of the Braking System of Urban Rail Vehicles

Abstract: The braking model of the train is crucial for design of ATO control law for train stop.In this paper,we propose a braking model and a method for identifying its parameters after reviewing the composition,characteristics and interface of the braking system of the urban rail train.The model is validated with data from field experiments.Its applicability for the control purpose has been demonstrated by the performance of an automatic stopping controller designed on the basis of the proposed braking model.

Urban tram braking system

Abstract: The invention relates to an urban tram braking system. The system comprises a braking instruction generation system, a braking control system and an anti-skid system, wherein the braking instruction generation system comprises a braking electronic control unit (BECU) and a braking control unit (BCU) and sends a braking instruction to the BECU; the BECU calculates required braking force according to the braking instruction and loading force detected by a loading pressure sensor and provides the braking force for a traction control unit; the traction control unit feeds a dynamic braking force signal back to the BECU; the BECU calculates air braking force which is needed to be supplemented and controls the BCU to generate braking cylinder pressure so as to realize braking control; the braking instruction generation system is provided with a driver controller, an emergency braking switch and a logic control unit connected with the emergency braking switch; the anti-skid system comprises a speed sensor arranged on a wheel axle and an anti-skid exhaust valve arranged on a braking cylinder pipe; the speed sensor detects a speed signal and transmits the speed signal to the BECU; and the BECU controls the action of the anti-skid exhaust valve according to the speed signal.

Apparatus for controlling motion of vehicle

Abstract: A vehicle motion controlling apparatus has an allocating unit for selecting steering or braking control mainly performed in cooperative control, receiving a desired value of vehicle turning motion, allocating steering and braking controls for the motion, determining main yaw rate from vehicle conditions, and determining a non-main yaw rate from difference between the desired value and the main yaw rate. Setting units set assist torque corresponding to the main yaw rate and braking torque corresponding to the non-main yaw rate when the steering control is selected and set braking torque corresponding to the main yaw rate and assist torque corresponding to the non-main yaw rate when the braking control is selected. The assist torque is generated for assisting a change of steering angle of vehicle in steering control. The braking torque is generated for applying braking force to wheel of vehicle in braking control.

Vehicle braking management for a hybrid power train system

Abstract: An exemplary system includes a vehicle having a drive wheel mechanically coupled to a drive shaft of a hybrid power train. The hybrid power train includes an internal combustion engine and an electric motor selectively coupled to the drive shaft. The internal combustion engine including a compression braking device. The system includes an electric generator selectively coupled to the drive shaft and coupled to an electrical storage device. The system includes a brake pedal position sensor that provides a braking request value. The system includes a controller configured to interpret the braking request value, a regenerative braking capacity, and a compression braking capacity. The controller is further configured to provide a regenerative braking command and a compression braking command in response to the braking request value, the regenerative braking capacity and the compression braking capacity.

Study on the Composite ABS Control of Vehicles with Four Electric Wheels

Abstract: Proposed a composite ABS control method for vehicles with four electric wheels, and simulated the method. By analyzing the characteristic curves of the four in-wheel electric motors, and some typical braking force distribution methods of composite braking for EV, a braking force distribution method for four-electric-wheel EV is presented. The method combined the ideal braking force distribution curve, and considered the ECE braking regulations, so it can guarantee both the braking stability and the energy recovery. Furthermore, a composite ABS control method was proposed base on the braking force distribution method. The composite ABS control method is a control method that the electric motor ABS control works together with the hydraulic ABS control. Both of the two modes of ABS control logic were using logic threshold control method. The model of the electric-wheel vehicle were established with AMESim, and the model of the composite ABS controller were built with Simulink. Co-simulation were carried out. Through analysis, a number of parameters curves were obtained. It proves that the composite ABS control method for four-wheel electric vehicles can effectively control the slip rate, and ensure braking stability.

Electric braking performance analysis of PMSM for electric vehicle applications

Abstract: This paper analyzed the performances of plug braking and regenerative braking of Permanent Magnet Synchronous Motor (PMSM), which is often used as the driving motor of electric vehicles. The electric braking principles are briefly explained at first. The performance analysis focuses on maximum braking torque, braking torque ripple and the feedback power of braking energy. The two main control methods for PMSM, six step commutation control and field oriented control (FOC), have been analyzed. A simulation system has also been developed in this paper and the analysis is supported by the results of simulation and preliminary experiments.

Gas turbine engine braking method

Abstract: The present disclosure discloses an engine braking system, especially for vehicles powered by a gas turbine. The engine braking system allows for control of engine braking force; control of over-speed of the power turbine and further includes means of recovering some or all of the braking energy of the engine braking system. Dissipative engine braking devices include an auxiliary compressor, or electrical generator, or an eddy current clutch or an eddy current brake, or fluid pump. Several methods of controlling the engine braking force of a dissipative braking device are disclosed and include (1) a continuously variable transmission (“CVT”); (2) an electrical generator and an optional thermal storage device; (3) an eddy current clutch; and (4) a fluid pump system. The various control devices may be operated automatically by appropriate algorithms. One of these control methods utilizes an eddy current clutch assembly. An innovative configuration of eddy current clutch assembly based on a brushless alternator is disclosed. Additional innovations include vehicle braking systems that utilize some or all the braking features to recoup a portion of braking energy available with either or both of a hybrid transmission and a dissipative braking device such as a compressor, an electrical generator or a fluid pump system.

Integrative braking control system for electric vehicles

Abstract: For Electric Vehicle (EV), energy saving and endurance mileage prolonging are very important. Regenerative braking techniques are key parts of electric techniques for saving energy. The traditional braking system must be updated to adapt the condition that the friction braking force is coexisting with the motor regenerative braking force. For the integrative braking control system it is so important to keep the traditional braking performance while recovering braking energy and fully exert the capability of the motor. In this paper, a new integrative braking control system will be studied. The simulation results based on the ADVISOR and the HIL test bench validate the effects of the system, such as energy recovering and braking performance.

Vehicle braking/driving force control system and vehicle braking/driving force control method

Abstract: Braking/driving force control that includes: detecting a driver's operating state for causing the vehicle to run; detecting a vehicle body motional state while the vehicle is running; computing a target longitudinal driving force for causing the vehicle to run and motional state amounts for controlling a vehicle body behavior on the basis of the detected operating state and motional state; and computing driving or braking forces allocated to the wheels so as to achieve the computed target longitudinal driving force and target motional state amounts and that the braking/driving force generating mechanism causes the wheels to generate independently.

Design and implementation of a regenerative braking system for electric bicycles based on DSP

Abstract: This paper proposes a regenerative braking system for electric bicycle based on DSP. The proposed method is used to adjust the switching sequence of the inverter, so that the braking energy will be returned to charge the battery. With the cooperation of regenerative braking energy recovery technologies and digital signal processor (TMS320LF2407) as the control unit, the regenerative braking energy is transformed to electrical energy and then returns to battery. The recovered energy can increase the driving endurance of the electric vehicles.

Research on regenerative braking control strategy of hybrid electric vehicle

Abstract: For the shortage of the original strategy of braking force distribution in hybrid electric vehicle (HEV) simulation software ADVISOR, a new model which the braking share of every braking force varies on the change of load was built from the standpoint of dynamics, based on the original regenerative braking control model. The model is simulated by ADVISOR software in HAFEI sample car and the simulation results show that the effect of energy recovery in new control strategy is superior to the original one, emissions of harmful gases are reduced and the motor efficiency is improved significantly. The braking force distribution method is also in accordance with ECE regulation. So the control strategy proposed in this paper is proved to be reasonable and effective. This kind of model expands the scope of the ADVISOR simulation effectively and facilitates the study of hybrid electric vehicle.

Design of an Anti-Lock Regenerative Braking System for a Series Hybrid Electric Vehicle

Abstract: In this paper, an adaptive rule based controller for an anti-lock regenerative braking system (ARBS) of a series hybrid electric bus (SHEB) has been proposed. The proposed controller integrates the regenerative braking and wheel antilock functions by controlling the electric motor of the hybrid vehicle, without using any conventional mechanical antilock braking system. The performance of the proposed system is evaluated by a comprehensive vehicle dynamics model in MATLAB/Simulink. Using the designed ARBS, the braking and regenerative performances of SHEB have significantly improved in slippery roads while the slip ratios are kept between 0.15 and 0.20.

Method and system for eliminating fuel consumption during dynamic braking of electric drive machines

Abstract: A drive system (100, 100a-c) for an electric drive machine (102, 102a-c) having an engine (104, 104a-c), a generator (106, 106a-c), a motor (108, 108a-c), final drive wheels (110, 110a-c) and auxiliary devices (116, 116a-c) is provided. The drive system (100, 100a-c) may include an inverter circuit (118, 118a-c) and an auxiliary driver (120, 120a-c). The inverter circuit (118, 118a-c) may be coupled to each of the generator (106, 106a-c) and the motor (108, 108a-c). The auxiliary driver (120, 120a-c) may be coupled to each of the generator (106, 106a-c) and the auxiliary devices (116, 116a-c). The inverter circuit (118, 118a-c) and the auxiliary driver (120, 120a-c) may be configured to automatically communicate power from the engine (104, 104a-c) and any power from the auxiliary devices (116, 116a-c) to the motor (108, 108a-c) in a propel mode, and automatically communicate power from the motor (108, 108a-c) to the engine (104, 104a-c), and optionally to a hybrid system (132) if applicable, in a dynamic braking mode so as to minimize fuel consumption during the dynamic braking mode.

Dynamic modeling of disc brake contact phenomena

Abstract: An interaction between a brake disc and friction material of automotive brake is characterized by a number of braking phenomena. These phenomena are influenced by brake operation conditions (applied pressure, speed, and brake interface temperature) and material characteristics of a friction couple. The dynamic and highly non-linear changes occurred in the contact of the friction pair, provokes hard-to-predict change of braking torque as the most important brake's output performance. Complex disc brake contact situation is causing sudden change of braking torque and could not be easily modeled and predicted using classical mathematical methods. That is why, the possibilities for development of the method for prediction of influence of braking regimes on generation of the stick-slip phenomena during a braking cycle has been investigated in this paper. Dynamic neural networks have been employed for development of the model of influences of the disc brake operation conditions on contact phenomena generation and 'nature' of braking torque change.

Regenerative control device and regenerative control method and hybrid motor vehicle

Abstract: A regenerative control capable of realizing a comfortable operation, along with an efficient collection of a regenerative energy of a motor generator and an effective regenerative braking control. A regenerative control device for a motor generator generates a regenerative braking power for decelerating a motor vehicle at a time of collecting regenerative energy generated by driving of the motor vehicle. The arrangement includes a driving state detection unit for detecting a driving state and a deceleration level acquisition unit for acquiring a deceleration level. A braking force setting unit sets the regenerative braking force of the motor generator at a time of detection of a deceleration operation by the driving state detection unit. A braking force adjustment unit adjusts and suppresses the regenerative braking force set by the braking force setting unit, according to acquired deceleration level.

Control apparatus for preventing rolling back of electrically driven vehicle upon start-up thereof

Abstract: In an electrically driven vehicle propelled by an electric machine (motor)equipped with a collaborative braking system of regenerative and frictional braking capacities, in order to achieve the “rollback prevention” at starting on an sloping road, when the regenerative braking is not available due to charging restriction to battery, frictional braking is used instead of regenerative braking and wheels are (automatically, i.e. not manually by driver) braked with friction to prevent the rollback. Moreover, in addition to braking wheels by frictional braking, further control is performed to adjust and match the magnitude of frictional braking force to a braking force in accordance with the starting operation. Thus, at the time of rollback prevention by the frictional braking as well, the similar prevention of rollback will be possible as the prevention by way of regenerative braking such that the effect of rollback prevention may be achieved without a feel of discomfort.

Optimized brake-based control of path lateral deviation for mitigation of secondary collisions

Abstract: This paper considers brake-based lateral control of a passenger vehicle, for reducing secondary collision risk following an initial impact in a traffic accident. Since secondary collisions are associated with deviations from the original travel path, the control problem is formulated via brake control sequences that minimize lateral path deviation. Optimal sequences are found not to conform to any simple control mode; sometimes all brakes are released, sometimes all wheels are locked, or the brakes may be applied in differential mode. In general, the optimal strategy combines several such actuation modes, and analysis shows it is related to the utilization of instantaneous vehicle force and moment capacity, indicating that a closed-loop control strategy may be developed based on the real-time estimation of tyre force limits during the post-impact event. Yaw motion control is related to response discontinuity and multiple equilibria found in the optimal response - a small change in initial yaw velocity generates large changes in the ensuing vehicle motion and thus in the aimed equilibrium point of the vehicle's orientation. Overall it is found that braking control strongly influences the post-impact path of the impacted vehicle, and may therefore form the basis of a practical system for avoiding secondary collisions in future traffic accidents.

Method of controlling braking in a vehicle

Abstract: A braking control system includes sensors for detecting pressure applied to a brake pedal. The system can also include a pressure sensor capable of detecting the hydraulic pressure of the braking system. The system can also include a position sensor for detecting a position of the brake pedal. The pressure applied to the brake pedal is compared to either the hydraulic pressure or the pedal position. If the resulting measurements are not correlated properly, braking countermeasures are applied. Braking countermeasures can include engine braking, regenerative braking, hydraulic assist, and brake pad assist.

ABS control design for two-wheel drive electric vehicles

Abstract: An ABS (Anti-lock Braking System) is a safety mechanism for vehicles which prevents the wheels of motor vehicles locked (ceasing of rotation) while braking. This research intends to develop and implement a non-mechanical ABS controller based on the application of regenerative and short-circuit braking mechanism in two-wheel electric vehicle. Boundary layer velocity control is proposed to ensure the optimized wheel-speed, under the minimum slip-ratio between tires and road.