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Showing papers on "Dynamic braking published in 1992"


Patent
07 Dec 1992
TL;DR: In this paper, the regenerative braking force for the driving wheel exceeds a theoretic distribution characteristic of the braking forces for the follower and driving wheels at least during an initial braking.
Abstract: In a brake system in an electric vehicle comprising a follower wheel capable of being hydraulically braked by the operation of a brake operating element, and a driving wheel connected to and driven by a motor using a battery as an energy source and capable of being hydraulically braked and regeneratively braked by the operation of the brake operating element, the regenerative braking force for the driving wheel exceeds a theoretic distribution characteristic of the braking forces for the follower and driving wheels at least during an initial braking. Thus, it is possible to sufficiently perform the recovery of the kinetic energy of the vehicle by the regenerative braking to increase the possible travel distance of the vehicle. In addition, at least during an initial braking, the hydraulic braking of the driving wheel and the hydraulic braking of the follower wheel are inhibited, and substantially only the regenerative braking of the driving wheel is performed. Thus, it is possible to recover the kinetic energy of the vehicle without consumption thereof by the hydraulic braking to increase the possible travel distance of the vehicle.

82 citations


Patent
07 Apr 1992
TL;DR: In this article, a regenerative braking control system consumes energy generated in a period corresponding to an angle ϑ₁ which starts in a half of a period of an AC voltage produced in a drive motor during the braking of the drive motor.
Abstract: A regenerative braking control system consumes energy generated in a period corresponding to an angle ϑ₁ which starts in a half of a period of an AC voltage produced in a drive motor during the braking of the drive motor. The regenerative braking control system also consumes energy generated in a period corresponding to an angle ϑ₂ that ends at the end of a half of a period of the AC voltage. The regenerative rate of braking control system utilizes a current induced in the driving coils of the drive motor at the end of the period corresponding to the angle ϑ₁ to recharge a battery. By utilizing two periods to carry out the regenerative braking process, the recharging energy and the braking force can be controlled individually. Moreover, a controller monitors the electric control system to determine whether a malfunction is present. If a malfunction is detected, an electrical brake electrically brakes the drive motor. This electrical braking after the detection of a malfunction in the electrical system provides satisfactory controllability of the electric vehicle.

68 citations


Patent
22 Jul 1992
TL;DR: In this article, a system and method for independently controlling the braking force applied to each wheel of an automobile based on the lesser of two target braking force calculations intended to produce a desired vehicular motion is presented.
Abstract: A system and method for independently controlling the braking force applied to each wheel of an automobile based on the lesser of two target braking force calculations intended to produce a desired vehicular motion. The first target braking force is based upon steering angle and vehicle sped, and is calculated so as to achieve a target value of a preselected motion variable, such as yaw rate, corresponding to the desired vehicular motion. The second target braking force is based upon individual wheel speed and is intended to maintain within a predetermined slip rate at least one wheel of the vehicle.

37 citations


Patent
03 Aug 1992
TL;DR: In this paper, an electrically controlled brake system including a brake operating member, a braking device braking a wheel of a vehicle, a second detector for detecting an actual braking effect provided by the braking device, and a controller for controlling the braking devices is presented.
Abstract: An electrically controlled brake system including a brake operating member, a first detector for detecting an operating amount of the brake operating member, a braking device braking a wheel of a vehicle, a second detector for detecting an actual braking effect provided by the braking device, and a controller for controlling the braking device. The second detector detects the actual braking effect in the form of a positive value when the vehicle is running in one of a forward and a backward direction, and in the form of a negative value when the vehicle is running in the other of the forward and backward directions. The controller determines a positive value as a target braking effect based on the detected operating amount of the brake operating member, and controls the braking device such that an absolute value of the detected actual braking effect coincides with the positive value of the determined target braking effect.

37 citations



Patent
27 Feb 1992
TL;DR: A ribbon tension control system uses dynamic braking of the drag motor, and includes drag circuitry with rectifier bridge circuitry and a constant current sink settable for drawing predefined selectable levels of current from the windings of a drag motor as mentioned in this paper.
Abstract: A pair of ribbon spools are independently operated by respective motors to rotate in one direction until the ribbon end and then in the opposite direction, and so forth. Spools alternately function as feed and take-up spools and motors as a drive and drag motors, respectively To eliminate excess drag motor cogging, a ribbon tension control system uses dynamic braking of the drag motor, and includes drag circuitry with rectifier bridge circuitry and a constant current sink settable for drawing predefined selectable levels of current from the windings of the drag motor. The motors are polyphase, permanent magnet, stepper motors which, when turned by the ribbon, generate alternating back emf signals in their windings. A full-wave rectifier bridge is connected to each winding of the drag motor with bridge outputs connected to a common sink which is an emitter follower circuit whose current level is set and maintained by an operational amplifier. The current level of the emitter follower circuit is set by adjusting the reference voltage of the amplifier using a resistive voltage divider network connected to a binary switch controlled by a microprocessor with a memory. The microprocessor monitors the back emf signals, periodically adjusts the rotational speed of the drive motor depending on distribution of ribbon, and adjusts the sink based on drag value tables stored in memory.

30 citations


Patent
15 Apr 1992
TL;DR: In this paper, a multi-disk braking system for a train is presented, where a set of metallic disks and carbon disks are coaxially installed on an axis of the train and actuated independently.
Abstract: PURPOSE: To ensure braking in a multi-disk braking device for a train, by coaxially installing a set of metallic disks actuated by a first pressure device and a set of carbon disks actuated by a second pressure so as to immediately actuate the metallic disks when stopping the train and to operate the carbon disks when an electrical retarder is abnormal. CONSTITUTION: A braking device 1 is equipped with a set of metallic disks 4 and a set of carbon disks 5 coaxially on an axis 2, which are respectively connected to pressure devices 6 and 7 and actuated independently. When a speed sensor CA senses that a train has been slowed down to a speed limit by actuating an electrical retarder RE to put on the brake, a pressure device 5 is actuated through a control logic device LA and an electrical hydraulic directional control valve DI, so that the metallic disks 4 stop the train. A pressure device 7 is actuated to operate the carbon disks 5 when a detector DE detects that the electrical retarder RE is abnormal. Thereby, the brake is effectively applied until the train is stopped.

25 citations


Patent
06 Feb 1992
TL;DR: In this paper, the hydraulic fluid pressure is adjusted by three-way valves under the control of relays wired to a stored-program controller, and additional inputs may be related e.g. to deceleration, vehicle loading or tyre adhesion.
Abstract: Strain gauges or magnetostrictive or piezoelectric force transducers (28) on the individual wheels (35) supply information on actual braking forces to signal processors (31) for comparison with an optimal setting worked out w.r.t. properties of the system. The hydraulic fluid pressure (P) is adjusted accordingly by three-way valves (34) under the control of relays (36) wired to a stored-program controller (32). Additional inputs (37) may be related e.g. to deceleration, vehicle loading or tyre adhesion. ADVANTAGE - Precise distribution of braking forces enhances safety with more efficient braking within shorter distances and without tendency to locking or yawing.

20 citations


Patent
22 Dec 1992
TL;DR: In this article, an electronically controlled braking system wherein improved braking distribution in a multi-axle vehicle is achieved by making allowance for sources of background braking by assessing through measurement the total background braking force and assigning this in a predetermined proportion between the vehicle axles.
Abstract: An electronically controlled braking system wherein improved braking distribution in a multi-axle vehicle is achieved by making allowance for sources of background braking by assessing through measurement the total background braking force and assigning this in a predetermined proportion between the vehicle axles.

20 citations


Patent
15 Jun 1992
TL;DR: In this article, a dynamic braking system resistor for stabilizing a power system during power system disturbances includes a braking resistor for coupling with the power system bus, and a valve responsive to the thyristor control signal couples the braking resistor with a ground potential.
Abstract: A dynamic braking system resistor for stabilizing a power system during power system disturbances includes a braking resistor for coupling with a power system bus. A controller monitors a power system parameter, such as the speed of a generator coupled with the power system bus, and determine therefrom a thyristor control signal. The controller uses the power system parameter to establish a desired modulation and then provides a bias to the desired modulation. The controller conditions the biased desired modulation signal to provide the thyristor control signal. A thyristor valve responsive to the thyristor control signal couples the braking resistor with a ground potential. A method is also provided of damping subsequent oscillations on a power system following a power system disturbance using the dynamic braking resistor.

18 citations


Patent
28 May 1992
TL;DR: In this paper, a power wheelchair (10) includes wheels (12a and 12b) that are reversibly driven by electric motors (24a and 24b) included in respective ones of electric motor drives (170).
Abstract: A power wheelchair (10) includes wheels (12a and 12b) that are reversibly driven by electric motors (24a and 24b) included in respective ones of electric motor drives (170). The electric motor drives (170) provide driving voltage pulses (142) of a pulse-width-modulated driving voltage (144) to respective ones of the motors 24a and 24b), and the electric motor drives (170) provide dynamic braking pulses (150) that are interposed intermediate of respective ones of the driving voltage pulses (142). The maximum width (146) of the driving voltage pulses (142) is selectively adjusted by a removable speed control knob (46) that is connected to a pair of ganged maximum speed potentiometers (48), thereby adjustably determining the maximum speed of the conveyance (10). The maximum torque of the power wheelchair (10) is selectively adjusted by a removable torque control knob (50) that is connected to a pair of ganged torque enhancement controls (52). Torque enhancement is achieved by sampling torque of each of the motors (24a and 24b) during a selected portion (190) of constant time periods (148) of the pulse-width-modulated driving voltage (144). Sampling of motor torque is done subsequent to a dynamic braking pulse (150) and prior to a driving voltage pulse (142) in a delay (164) for a portion (190) of a constant time period (148).

Patent
23 Nov 1992
TL;DR: In this paper, a low-loss braking of an electrically driven vehicle with two electric motors connected in parallel and arranged one on each side of the vehicle and which are controlled by a pulse control is proposed, for one, to brake the vehicle above a prescribed rpm threshold value by useful current braking, and below it by means of regenerative braking.
Abstract: For the low-loss braking of an electrically driven vehicle with two electric motors connected in parallel and arranged one on each side of the vehicle and which are controlled by a pulse control, it is proposed, for one, to brake the vehicle above a prescribed rpm threshold value by useful-current braking, and below it by means of regenerative braking. Secondly, instead of an rpm threshold value, the battery current can also be used as the criterion for one of the two different braking types. A high heat generation in the motors is avoided and energy is saved by this braking process. An electric switching circuit for the conversion of this process is indicated.

Patent
26 Jun 1992
TL;DR: In this paper, the bridge drive motor is prevented from "driving through the brake" when the hydraulic brake is being applied to result in significant retarding torque, and the machine is retarded solely by application of the manually operated brake until the machine reaches a very slow speed.
Abstract: The inventive method and machine are improvements in aspects of a material handling machine (such as an overhead travelling crane) having an electrically-powered traverse drive, e.g., a bridge drive. Such machine has (a) regenerative motor braking and (b) a manually-applied hydraulic brake, both for retarding the machine. The invention prevents the bridge drive motor from "driving through the brake" when the hydraulic brake is being applied to result in significant retarding torque. When the hydraulic brake is pedal-applied, an electrical contact closes at a predetermined hydraulic pressure and other devices, relays and the like, are actuated to modify operation of the controller and prevent "motoring" simultaneous with hydraulic braking. Regenerative braking is likely to be set for a retardation rate less than results from application of the hydraulic brake. The invention prevents the drive motor and hydraulic braking system from "fighting." With the invention, the motor control unit is disabled at some predetermined pressure in the brake hydraulic line. Thereafter, the machine is retarded solely by application of the manually-operated brake until the machine reaches a very slow speed.

Patent
23 Jul 1992
TL;DR: In this article, a rolling stock comprising a motor, receiving AC power obtained by inverting DC power through an inverter and producing driving power, is subjected to dynamic braking by feeding electromotive force from the motor to a motor fan connected in parallel with a dynamic brake resistor thereby cooling the resistor forcibly and positively.
Abstract: PURPOSE:To enhance reliability when a rolling stock comprising a motor, receiving AC power obtained by inverting DC power through an inverter and producing driving power, is subjected to dynamic braking by feeding electromotive force from the motor to a motor fan connected in parallel with a dynamic brake resistor thereby cooling the resistor forcibly and positively. CONSTITUTION:DC power is inverted through a VVVF inverter 1 into AC power which is then fed through a circuit breaker 2 to a linear synchronous motor(LSM) 3 thus producing thrust in a rolling stock 4 opposing thereto. When the rolling stock 4 is subjected to dynamic braking, the circuit breaker 2 is opened while a brake circuit breaker 5 is closed to operate the LSM 3 as a generator and supplies electromotive force therefrom to a dynamic brake resistor 6 and a motor fan 8. Power is consumed through the dynamic brake resistor 6 which is forcibly cooled through the fan 8. This constitution prevent temperature rise of the resistor 6 positively thus enhancing reliability.

Patent
01 Sep 1992
TL;DR: In this paper, a regenerative braking system in a motor vehicle determines a state of deceleration on the basis of the number of revolutions of a motor and an accelerator signal and performs a Regenerative braking according to the state.
Abstract: A regenerative braking system in a motor vehicle determines a state of deceleration on the basis of the number of revolutions of a motor and an accelerator signal and performs a regenerative braking according to the state of deceleration. The regenerative braking system includes a revolution sensor for detecting the number of revolutions of a rotor of a vehicle driving motor and an accelerator opening sensor in a RAM stores discrimination data for discriminating between a regenerative braking mode and a drive mode on the basis of the number of revolutions of the rotor and the accelerator opening and also stores on-off duty ratio data of FETs in the regenerative braking mode and that in the drive mode. A CPU retrieves on-off duty ratio data corresponding to the number of revolutions of the rotor and the accelerator opening in the regenerative braking mode when the regenerative braking mode is determined on the basis of the rotor revolutions and the accelerator opening, and controls the FETs at an on-off duty ratio corresponding to the retrieved on-off duty ratio data.


Proceedings ArticleDOI
03 Aug 1992

Patent
23 Jul 1992
TL;DR: In this article, a braking system for electrically driven vehicles consists of a driven front axle (VA) and an undriven rear axle (HA) in the form of a triple-circuit (I, II, III) compound system consisting of hydraulic friction brakes (3, 4, 10, 11), and an electro-regenerative (II) braking system, which makes use of one of the electric drive motors of the motor vehicle for braking and power recovery.
Abstract: A braking system for electrically driven vehicles consists essentially of a driven front axle (VA) and an undriven rear axle (HA) in the form of a triple-circuit (I, II, III) compound system consisting of hydraulic friction brakes (3, 4, 10, 11) and an electro-regenerative (II) braking system, in which the electro-regenerative braking system makes use of one of the electric drive motors of the motor vehicle for braking and power recovery. The actuation of the friction brakes connected to the second and third braking circuits and the braking force distribution between the front and rear axles are controllable by means of an electronic regulator which receives information via e.g. the brake pedal position and evaluates this information to control the brakes acting on the driven wheels.

Patent
15 Apr 1992
TL;DR: In this paper, a method of controlling the braking behavior of various wheels of a vehicle during a normal braking mode and during an antilock braking mode of operation is presented, using a control unit which calculates various parameters over a known time increment (t-t1).
Abstract: A method of controlling the braking behaviour of various wheels of a vehicle during a normal braking mode of operation and during an antilock braking mode of operation, the method using a control unit which calculates various parameters over a known time increment (t-t1), the method including the steps of: obtaining a value of the actual rotational velocity of each wheel (W1, W2); generating a first signal indicative of braking effort P(in) or desired vehicle deceleration; generating a per wheel velocity command signal the slope or deceleration of which is proportional to the desired vehicle deceleration p(in) and a multiplicative scale factor (ABSGi+GI) for adjusting such deceleration during the normal braking mode and antilock braking mode, generating a per wheel error signal Ei as a difference between the wheel velocity command and actual rotational velocity of each wheel; operating upon the error signal Ei to generate a brake activity command signal Bi, regulating brake force in response to the brake activity command signal Bi.

Patent
12 Aug 1992
TL;DR: In this paper, an electric motor drive system for a motor vehicle consisting of switching means 42, (T1, T2, Fig. 12) for selectively supplying current from a power source, including a battery (18, Figs 1 and 12), coupled to the switching means for operating the motor 14 in an actuation mode for moving the vehicle and a braking mode for applying dynamic braking to the motor.
Abstract: An electric motor drive system for a motor vehicle (10, Fig. 1) comprises switching means 42, (T1, T2, Fig. 12) for selectively supplying current from a power source, including a battery (18, Figs 1 and 12) to the motor 14 and control means 24-40 coupled to the switching means for operating the motor 14 in an actuation mode for moving the vehicle and a braking mode for applying dynamic braking to the motor. Additionally the switching means (T1, T2, Fig. 12) is operable to operate the motor in a regenerative braking manner during the braking mode for generating a charging current to the battery (18). In the actuation mode a transistor (T2) is conductive to energise field windings (LA, LF) of the motor. In the dynamic braking mode the transistor (T2) is turned off and a further transistor (T1) is turned on. In the regenerative braking mode the further transistor is also turned off and energy generated by the motor is fed to the battery (18). The control means may include a microprocessor 32. A generator (20, Fig. 12) with an internal combustion engine may be used to charge the battery (18). Electronic circuitry is used to ensure that regenerative circuit is generated even if the motor Emf is lower than the voltage of the battery 18.


Patent
02 Apr 1992
TL;DR: In this article, the authors define a relationship between a braking pressure and the braking force as a braking characteristic value, and determine the braking efficiency in each interval and compared with a threshold value dependent on the braking system to determine its functional state.
Abstract: The method involves defining a relationship between a braking pressure and the braking force as a braking characteristic value. The braking process is divided into several measurement time intervals. The braking efficiency is determined in each interval and compared with a threshold value dependent on the braking system to determine its functional state. ADVANTAGE - Simple and reliable method.

Patent
13 Oct 1992
TL;DR: In this article, the operating point on the brake control plot is shifted towards smaller grip factors, i.e. to reduce the braking effect and increase the brake modulation, for a more stable braking effect while cornering.
Abstract: Dynamic sensors (2,3,3) on the vehicle measure the actual cornering settings of the vehicle and compare them with the settings of the steering controls. This produces a slip factor which is used to correct the ABS control for a more stable braking effect while cornering. The operating point on the brake control plot is shifted towards smaller grip factors, i.e. to reduce the braking effect and increase the brake modulation. The vehicle speed, lateral acceleration and steering setting provide the main parameters. The rate of change of the correction factor is also computed in the control unit (1) for a more responsive correction control. ADVANTAGE - Improved cornering stability, safer cornering control.

Patent
15 Apr 1992
TL;DR: In this paper, the authors proposed to improve steering accuracy of rear wheels by intercepting the drive current of each electric motor in order while leaving an interval before a target rotating speed of the motor at the time of rear wheel steering, and performing braking there in after intercepting drive current to at least one electric motor.
Abstract: PURPOSE:To improve steering accuracy of rear wheels by intercepting the drive current of each electric motor in order while leaving an interval before a target rotating speed of the motor at the time of rear wheel steering, and performing braking there in after intercepting the drive current to at least one electric motor. CONSTITUTION:At the time of rear wheel steering, the drive current of a first motor 2a is intercepted while leaving prescribed rotating speed A before the rotating speed N, and after a little interval the drive current of a second motor 2b is intercepted while leaving prescribed rotating speed B before the target rotating speed N. At the almost same time of interception of the drive current of the second motor 2b braking in the first motor 2a is begun, and further after a little interval braking in the second motor 2b is begun while leaving prescribed rotating speed D before the target rotating speed. Namely, stop control against the first and second motors 2a, 2b are performed little by little, and hence the rotating speed as the whole motors is facilitated to correspond to the target rotating speed. Further, overrun due to inertia can be prevented by dynamic braking.

Patent
Shohei Matsuda1, Jiro Suzuki1, Tsuyoshi Satoh1, Kazutoshi Tashima1, Toshio Yahagi1 
22 Jun 1992
TL;DR: In this article, a method for generating braking forces in the brake devices for driving wheels when excessive slipping has occurred in the drive wheels involves an independent control mode for independently controlling respective braking forces of the plurality of drive-wheel brake devices and a collective control mechanism for collectively controlling the braking forces.
Abstract: A traction control method for a vehicle according to the present invention for generating braking forces in the brake devices for driving wheels when excessive slipping has occurred in the drive wheels involves an independent control mode for independently controlling respective braking forces of the plurality of drive-wheel brake devices and a collective control mode for collectively controlling the braking forces. These two control modes are interchangeable with each other. This enables traction control which can insure both reliable driving force and high stability.

Patent
24 Jan 1992
TL;DR: In this paper, an improved electrical circuit configuration for a chopper circuit is disclosed which is particularly adapted for use with an inductive load such as a braking resistor (38) of the type used in many rapid transit vehicles.
Abstract: An improved electrical circuit configuration for a chopper circuit is disclosed which is particularly adapted for use with an inductive load such as a braking resistor (38) of the type used in many rapid transit vehicles. Instead of connecting a di/dt reactor directly in series with the electronic switch of the chopper circuit, a di/dt reactor (84) is connected in series with the freewheeling diode (46). Using this configuration, the di/dt reactor (84) does not have to continuously handle the average current through the electronic switch (42) during the entire chopping operation. Hence, a much smaller, lighter, and less expensive di/dt reactor (84) can be utilized.

Patent
09 Sep 1992
TL;DR: In this article, the authors proposed a utility model for an AC asynchronous motor braking controller, which combines a capacitor dynamic braking circuit and a DC energy consumption braking circuit by utilizing a control circuit of a contactor of residual magnetism voltage passive attracting.
Abstract: The utility model relates to an AC asynchronous motor braking controller, which combines a capacitor dynamic braking circuit and a DC energy consumption braking circuit by utilizing a control circuit of a contactor of residual magnetism voltage passive attracting. The utility model can not only control conveniently and effectively motors which have a large capacity and large load inertia to brake smoothly, but also fit for frequent brakes, and the utility model is suitable for the frequent, quick and smooth braking of the motor dragging of devices of machinery, light industry, textiles, etc.


Patent
Alan August Fennema1
01 Apr 1992
TL;DR: In this paper, the head carriage of a servo is automatically stopped by dynamic braking through use of a power amplifier which is switched from a transconductance mode used during normal servo positioning operations to a voltage amplifying mode which is set to a zero input for dynamically braking the servo position system to a safe speed and thence to a stop condition whereupon further error recovery procedures may be employed.
Abstract: A servo positioning system, such as used in an optical disk or other types of disk drives includes focus and positioning servo circuits. When a focus error is detected, then it is desired to stop the operation of the positioning system. Similarly, when a positioning error is detected, such as excessive speed or a non-zero velocity at the end of a seek or positioning motion, the head carriage should also be stopped. The stopping of the head carriage is by dynamic braking through use of a power amplifier which is switched from a transconductance mode used during normal servo positioning operations to a voltage amplifying mode which is set to a zero input for dynamically braking the servo positioning system to a safe speed and thence to a stop condition whereupon further error recovery procedures may be employed.