Showing papers on "Dynamic braking published in 2002"

Regenerative braking system for a hybrid electric vehicle

Abstract: This paper discusses a regenerative braking system (RBS) for a parallel hybrid electric vehicle (PHEV) that performs regenerative energy recovery based on vehicle attributes, thereby providing improved performance, efficiency and reliability at minimal additional cost. A detailed description of the regenerative braking algorithm is presented along with simulation results from a dynamic model of the PHEV exhibiting the regenerative braking performance.

Evolution of Electronic Control Systems for Improving the Vehicle Dynamic Behavior

Abstract: Starting with ABS (Antilock Brake System) the steps towards integrated active safety systems dealing with vehicle dynamics is shown. While ABS and TCS were initially designed as open loop controllers for the lateral vehicle motion a first approach towards closed loop control of the lateral vehicle motion for active safety systems was realized by ESP (Electronic Stability Program. Estimation algorithms and model following control are used with ESP to compensate for the lack of sensors. Since 2001 ESP is available for cars with an electro hydraulic brake system. The extension of ESP in combination with active front steering is expected to enter the market in 2003.

Independent braking and controllability control method and system for a vehicle with regenerative braking

Abstract: A strategy is provided using feedback control algorithms to monitor and dynamically modify front and rear braking torque to maintain controllability in a vehicle that initially favors regenerative braking. Simple proportional-integral-derivative feedback controllers can be used. The controller can monitor wheel speed, lateral acceleration, yaw rate, and brake position to selectively activate non-regenerative braking independently for each individual wheel and regenerative braking in varying proportion based on at least one actual vehicle controllability value and at least one predetermined target value for controllability and optimization of energy recovery. Controllability factors can include predetermined longitudinal slip ratio, comparison of tire slip angle or yaw rate. For rear wheel drive configurations, the non-regenerative brakes can be applied to just one front axle wheel on the outside of a turn. For front wheel drive configurations, the non-regenerative brakes can be applied to just one rear axle wheel on the inside of a turn.

Braking force control apparatus for a vehicle

Abstract: Each of target braking forces for front and rear wheels of a vehicle is calculated based on an amount of braking performed by a driver and a predetermined braking force distribution ratio between the front wheels and the rear wheels Each of the target regenerative braking forces for the front and rear wheels, respectively, is calculated based on a corresponding one of the target braking forces such that a maximum regeneration efficiency is obtained If the driver has performed an abrupt braking operation, if the driver has performed a braking operation when the vehicle runs at a high deceleration, or if the vehicle runs at a high lateral speed, it is quite likely that anti-skid control will be started afterwards Therefore, the target regenerative braking forces are gradually reduced, and target frictional braking forces are gradually increased If anti-skid control is started, the target regenerative braking forces are set as 0

Dynamic driving/braking force distribution in electric vehicles with independently driven four wheels

Abstract: A novel algorithm for the dynamic driving/braking force distribution is proposed for electric vehicles (EV) with four in-wheel motors. In such EVs, the vehicle lateral motion can be controlled by a yaw moment, generated by the torque difference between wheels. This method is known as DYC (Direct Yaw moment Control) in ordinary engine vehicle engineering; however, the torque difference can be generated more directly with in-wheel motors. One problem of DYC is its instability on slippery roads, such as wet or snowy asphalt. To achieve high stability, the loads of wheels are preferably equal. The load on each wheel can be evaluated as the square root of the sum of squares of driving/braking force and side force. Therefore, the driving/braking forces, or motor torques, should be distributed depending on the side forces of the wheels, to minimize the load imbalance between wheels. The proposed algorithm can solve this optimization problem approximately with little calculation cost, and thus this method can be applied for real-time calculation within a control period. Approximate solutions obtained with the proposed method are evaluated by comparison with numerical solutions that require much calculation time. The difference between these solutions is shown to be negligible, indicating the effectiveness of the proposed method. © 2001 Scripta Technica, Electr Eng Jpn, 138(1): 79–89, 2002

Vehicular braking control apparatus and braking control method thereof

Abstract: A vehicular braking control apparatus and method controls frictional braking performed by a frictional braking device, controls regenerative braking performed by a regenerative braking device, and controls shifting between a cooperative braking mode, realized by the frictional braking and the regenerative braking, and a single braking mode, realized by only the frictional braking. A correction coefficient for one of a frictional braking control amount and a regenerative braking control amount is calculated on the basis of an actual degree of vehicle deceleration and a reference degree of vehicle deceleration based on an amount of braking operation performed by a driver during braking in the single braking mode. The control amount is corrected based on the correction coefficient.

Braking and controllability control method and system for a vehicle with regenerative braking

Abstract: The present invention provides a method and system to use feedback control algorithms to monitor and dynamically modify front and rear braking torque to initiate braking based on driver demand, initially favoring regenerative braking more than conventional braking balance would indicate while monitoring and maintaining vehicle controllability factors such as oversteer and understeer. A simple proportional-integral-derivative feedback controller can be used. Vehicle sensors for wheel speed, lateral acceleration, yaw rate, and brake position can provide input to the controller to monitor vehicle conditions and to activate non-regenerative and regenerative braking in varying proportions based on at least one actual vehicle controllability value and predetermined target value for controllability and optimization of energy recovery. Controllability factors can include predetermined longitudinal wheel slip ratios or a comparison of tire slip angle or yaw rate to a target value.

Adaptive Continuously Variable Compression Braking Control for Heavy-Duty Vehicles

Abstract: Modern heavy-duty vehicles are equipped with compression braking mechanisms that augment their braking capability and reduce wear of the conventional friction brakes. In this paper we consider a heavy-duty vehicle equipped with a continuously variable compression braking mechanism. The variability of the compression braking torque is achieved through controlling a secondary opening of the exhaust valve of the vehicle's turbocharged diesel engine using a variable valve timing actuator A model reference adaptive controller is designed to ensure good vehicle speed tracking performance in brake-by-wire driving scenarios in presence of large payload and road grade variations. The adaptive controller is integrated with backstepping procedure to account for compression braking actuator dynamics, with observers for various unmeasured quantities and with compensation schemes for actuator saturation. In addition to speed tracking, the vehicle mass and road grade are simultaneously estimated if persistence of excitation-type conditions hold. The final version of the controller is successfully evaluated on a high order crank angle model of a vehicle with a six-cylinder engine.

Antilock braking system based roll over prevention

Abstract: A rollover prevention system for a vehicle includes an antilock braking system and a plurality of wheel-end modulator valves associated with respective wheels. The antilock braking system includes an electronic control unit and a lateral acceleration estimator for determining a lateral acceleration of the vehicle. The wheel-end modulator valves cause respective braking pressures to be applied at the respective wheels as a function of the lateral acceleration of the vehicle and a level of frictional contact between the wheels and a driving surface.

Automatic braking device

Abstract: A plurality of automatic brake devices having different braking characteristics are appropriately operated in response to a braking request issued from various safety devices of a vehicle. A vehicle VL includes a hydraulic brake device 2 on each of wheels 4FR to RL, and an electric parking brake 3 for braking rear wheels. The brake control ECU 1 transmits, via the in-vehicle LAN bus 6, detection values from various sensors 8 and braking requests from braking request output means including safety devices such as a congestion following control ECU 71, an inter-vehicle control ECU 72, and a sleep prevention ECU 73. Then, the magnitude of the braking request is determined according to the vehicle speed and other vehicle conditions, and based on the determination result, an operation signal for operating the hydraulic brake device 2 and the electric parking brake 3 simultaneously or by switching is output. [Selection diagram] Fig. 1

Combined regenerative and friction braking system for a vehicle

Abstract: A combined regenerative and friction braking system for the road wheels of a vehicle includes a friction braking subsystem, a regenerative braking subsystem coupled to the road wheels equipped with the friction braking subsystem, and a brake system controller for controlling both the friction and regenerative braking subsystems such that regenerative braking is restored to a maximum practicable value following conclusion of an antilock braking event.

Brake control for vehicle

Abstract: A brake control apparatus for a vehicle includes an actuating section to apply a regenerative braking force to a motor-driven wheel driven by a motor of the vehicle. A control section is arranged to vary the regenerative braking force in a direction to shift a front and rear wheel braking force distribution toward an ideal braking force distribution, in accordance with a wheel locking tendency of the motor-driven wheel when the regenerative braking force exceeding a braking force determined by the ideal braking force distribution is applied to the motor-driven wheel.

Braking/driving control apparatus and method for automotive vehicle

Abstract: In braking/driving force controlling apparatus and method for an automotive vehicle, a state discriminating section discriminates between a parking state in which a manipulation for the vehicle to be parked is carried out and a non-parking state in which no manipulation for the vehicle to be parked is carried out, a controller detects a manipulated variable of a manual input section, generates a constant target vehicle speed corresponding to the detected manipulated variable in a case where the state discriminating section discriminates the parking state, calculates a vehicular braking/driving force for a present vehicle speed to become the target vehicle speed, and controls the vehicular braking/driving force on the basis of the calculated braking/driving force.

Prediction of maneuver trajectory for automobile during braking, controls the anti lock braking and steering system based upon trajectory prediction dependent upon the relative speeds and distance between two vehicles

Abstract: The control of the anti lock braking and steering system is based upon trajectory prediction dependent upon the relative speeds and distance between two vehicles (V1,V2). In one scenario the distance (15) is sufficiently great with the existing relative speed that straight line braking is possible in order to avoid a collision. In other instances a maneuver is needed (11,14) to maintain maximum contact of wheels with road.

Cooperative control device for air over hydraulic brake

Abstract: PROBLEM TO BE SOLVED: To prevent occurrence of a shortage of slowdown speed due to a deviation between regenerative braking and frictional braking that is caused by a delay in response for the command value of the frictional braking when switching from the regenerative braking to the frictional braking. SOLUTION: The following describes when master cylinder hydraulic pressure Pmc is generated by treading a brake pedal at t1 and the vehicle speed VSP decreases as shown. Regenerative braking torque is used until the moment t2, during the period of a high speed area with vehicle speed Vlmth or more at the start of a regenerative braking control performing the regenerative braking accurately, and a command value Tmcom2 for regenerative braking torque is decreased in a second order curve as shown in solid line as the speed VSP decreases when the speed VSP becomes less than Vlmths, and then the target braking torque for the vehicle is achieved by the increase of the command value Pbcomf for brake hydraulic pressure (frictional braking torque). Since the total target braking torque is a sum of values of Tmcom2 and Pbcomf, Pbcomf is also increased in the second order curve. Accordingly a deviation between the two types would not widen even because of a delay in response for the command value for the frictional braking, and that diminishies a temporal shortage of the slowdown speed due to the deviation and allows a smooth transition from the regenerative braking to the frictional braking. COPYRIGHT: (C)2004,JPO&NCIPI

Method for operating a vehicle braking system uses devices to determine the temperature of a braking area/surface by relying on deceleration/acceleration after activating the vehicle's braking system

Abstract: Devices (TEMP,MEM) determine the temperature of a braking area/surface (BD) i.e. disks or linings by relying on slowing down or acceleration as a vehicle's braking system is activated. After the braking system is activated, control devices (BS,ECU,MEM) control the level of braking force on the braking area/surface by relying on the temperature of the braking area/surface. An independent claim is also included for a device for operating a vehicle braking system.

Trailer braking system

Abstract: A trailer braking system includes a controller that supplies pressurized air or hydraulic fluid to an actuator that powers a master brake cylinder on the trailer. A pressure sensor is supplied to provide feedback to the controller so that the controller may vary the braking force being generated by the system. The trailer braking system includes an indicator system that allows the driver of the vehicle towing the trailer to readily determine the status of the trailer braking system.

Method for eliminating fuel use during dynamic braking

Abstract: A dynamic braking system for a vehicle, the system comprising an engine, an alternator, a plurality of alternating current (AC) electric traction motors, each coupled in driving relationship to a respective one of a plurality of driven wheels, a plurality of power inverters where each of the traction motors has excitation windings coupled in circuit with a corresponding one of the plurality of power inverters, a fuel-free dynamic braking controller, a fuel-free dynamic braking transfer switch located between one of the plurality of traction motors and the one of the plurality of power inverters in circuit with the corresponding one of the plurality of power inverters, wherein the one of the plurality of traction motors in circuit with the corresponding one of the plurality of power inverters that is separated by the fuel-free dynamic braking transfer switch does not generate and does not consume power, and wherein the fuel-free dynamic braking controller commands one of the plurality of power inverters that is separated by the fuel-free distributed braking transfer switch from one the traction motor to convert direct current (DC) power into AC power for use by the vehicle.

Engine cylinder power measuring and balance method

Abstract: An accurate method of determining the power developed by selected cylinders of a multiple cylinder engine is based on the concept of controlling engine rpm for test purposes by adjusting the load on the engine instead of controlling speed by adjusting the fuel rate as is commonly done in normal engine operation. The method may be utilized for evaluating cylinder performance and for accurately balancing the output of the individual cylinders. It is particularly useful in railroad applications where the engine operates a generator that produces electric power and the system is provided with dynamic braking grids, which can be utilized as resistor grids for load testing the engine. However, the method is also applicable to other engines and other engine arrangements where engine power may be absorbed by a generator or dynamometer for controlling the load for test purposes.

Braking performance simulation for a tractor-semitrailer vehicle with an air brake system:

Abstract: Recently safety systems for commercial vehicles have been developed rapidly. However, there are still many problems in the vehicle stability and the braking performance. In particular, a commercial vehicle may meet a dangerous braking condition when the vehicle is lightly loaded or empty and when the road is wet or slippery. Under these conditions, the truck can spin out, the tractor can jackknife or the trailer can swing out. To design an air brake system for a commercial vehicle, since the air brake system has many design variables, there must be intense research on a method on how to prevent dynamic instability and how to maximize vehicle deceleration. In this study, mathematical models of the tractor-semitrailer and the air brake system including an antilock brake system controller have been constructed for computer simulation. Also, simcopy IMple examples are applied to show the usefulness of the program. Designers can use this simulation program for understanding the braking characteristics ...

Dual-frequency braking in AC drives

Abstract: Many variable frequency drive (VFD) applications require infrequent or partial braking. The use of a regenerative circuit, or of a dynamic braking resistor, adds significant cost to the VFD. This paper presents a method to obtain braking torque in nonregenerative AC drives without the need for additional power circuits. With this method, braking energy is absorbed from the rotating inertia at the applied frequency and is dissipated in the motor at a second loss-inducing frequency. Theoretical results that illustrate the usefulness and limitations of the proposed approach are given. Test results with low-voltage and medium-voltage drives are included in this paper. As compared to DC injection braking, the proposed method allows continuous estimation of motor speed and gives much higher braking torque per ampere.

Control of an automatic vehicle clutch and/or gearbox, uses an automatic and controlled operation of the vehicle brakes to interrupt the tensile load when changing gears

Abstract: For the automatic control of a clutch and/or the automatic vehicle gearbox, the gear shift action is accompanied by an interruption in the tensile load. A braking action is applied during a forward motion, using the vehicle brakes automatically to compensate for a loss of braking forces during gear shifting, using a braking torque which equals the difference between the motor thrust torque and the transmitted clutch torque.

Method and apparatus for braking a hybrid electric vehicle

Abstract: A method and system for braking a hybrid electric vehicle having an internal combustion engine and a traction motor coupled to a common output shaft, with the vehicle also having an energy storage battery. The method includes monitoring of the vehicle to determine if the vehicle's driver is operating the vehicle in a braking mode and if so, controlling the engine and traction motor so as to provide dynamic braking such that when the traction motor is operated regeneratively, the brake torque produce by the engine is reduced from a maximum contemporaneous brake torque value.

Work machine having a drive train with an enhanced engine braking mode

Abstract: An enhanced braking mode for a work machine includes activating engine compression release brakes while placing a torque converter in an overspeed condition. By doing so, both the engine and the torque converter contribute to decelerating the work machine. This combined braking horsepower is greater than that available using the engine compression release brakes with the torque converter in a locked condition. In addition, the braking horsepower available in this enhanced braking mode is comparable to that available with the employment of hydraulic retarders, which can be substantially more expensive, and require additional hydraulic cooling system capability. The enhanced braking mode is preferably carried out automatically by the electronic control module when the vehicle is in a retarding mode.

Method and device for improving braking behavior

Abstract: A method to improve the braking behavior of a vehicle is provided, in which it is not permitted to exceed a maximum allowable braking pressure difference between the braking pressures on the two wheels of one axle, and in which the maximum allowable braking pressure difference between the wheels of one axle is a function of at least one variable describing the vehicle dynamics When an unstable behavior of the vehicle is recognized, the maximum allowable braking pressure difference between the wheels of the axle is maintained or reduced

Apparatus for controlling deceleration of DC motor

Abstract: An apparatus for controlling deceleration of a DC motor which is driven in a forward operating direction with a forward-drive electric current applied thereto by a forward driving device, wherein the forward motor driving device applies the forward-drive electric current in the form of pulses to the DC motor during its deceleration, and wherein a plugging-braking device operable while the motor is subjected to a regenerative brake or operated in a non-braked state is operated to apply a reverse-drive electric current in the form of pulses to the motor, to apply a plugging brake to the motor, such that at least one pulse of the reverse-drive electric current follows every predetermined number of pulses of the forward-drive electric current. The plugging-braking device may be replaced by a dynamic braking device operable to short-circuit the motor to apply a dynamic brake to the motor, with at least one pulse of a dynamic-brake current following every predetermined number of pulses of the forward-drive electric current.

Electric steering controller and antiskid controller for vehicle having the same

Abstract: PROBLEM TO BE SOLVED: To easily perform countersteering operation when giving braking force on a so-called μ split road surface in an electric steering controller. SOLUTION: In a steering torque control block B0, steering torque for a steered wheel of a vehicle is controlled in accordance with steering operation. Moreover, in a braking force inference block B1, braking force given to each wheel of the vehicle is inferred to infer a difference in braking force given to right and left wheels in a right and left braking force difference inference block B2 based on the braking force inferred in the block B1. Assist steering torque is given to the steering torque control block B0 by an assist steering torque giving block B3 in accordance with a difference in braking force on the right and left wheels to assist operation when performing countersteering. COPYRIGHT: (C)2004,JPO