KR101393284B1 - Apparatus and method of prohibiting from locking in electric vehicle - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a braking method and apparatus for preventing a wheel from being locked during braking in an electric vehicle using hydraulic braking and regenerative braking, and more particularly, And more particularly to an anti-wheel braking method and apparatus for an electric vehicle for preventing a wheel locking phenomenon that may occur.
According to the present invention, when a mechanical lock-up phenomenon occurs in a mechanical hydraulic braking apparatus, a short-time positive torque is intermittently output to an electric motor, thereby solving the wheel locking phenomenon of the mechanical hydraulic braking apparatus.

Description

TECHNICAL FIELD [0001] The present invention relates to an anti-lock braking method and apparatus for an electric vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a braking method and apparatus for preventing a wheel from being locked during braking in an electric vehicle using hydraulic braking and regenerative braking, and more particularly, And more particularly to an anti-wheel braking method and apparatus for an electric vehicle for preventing a wheel locking phenomenon that may occur.

An electric vehicle refers to an automobile that uses an electric energy of a battery to drive an electric motor and uses the driving force of the electric motor as a whole or a part of the power source. Electric vehicles include pure electric vehicles that use only electricity as driving power, and hybrid electric vehicles that use the driving power of an existing internal combustion engine and the driving force of an electric motor together.

Pure electric and hybrid electric vehicles use conventional mechanical hydraulic braking and electric braking when braking.

An electric motor that drives the wheels of an electric vehicle can operate as a generator by changing the circuit. When the electric motor operates as a generator, a force to rotate in a direction opposite to the direction of rotation, that is, a braking force, is generated. When this principle is used, the electrical weakness of the mechanical hydraulic braking device Braking is possible.

Such electric braking is classified into power generation braking, which discharges electricity generated during braking to the outside through a resistor, and regenerative braking, which uses the generated electricity to charge the battery. Regenerative braking This is mainly used.

On the other hand, when the vehicle suddenly stops, the wheel may slip due to a mismatch between the speed of the wheel and the vehicle speed. When such a wheel-locked section occurs, the vehicle wheel loses friction with the ground, slips, and eventually becomes out of steering.

In order to prevent such unsteady state, conventionally, an ABS (anti-lock brake system) is mounted on a mechanical hydraulic braking device to solve the problem. ABS is also used in electric vehicles to solve the wheel lock problem.

Since electric vehicles can use both hydraulic braking and regenerative braking, there is a need for a technique that can solve the wheel locking problem by controlling the torque of the electric motor without installing the ABS in the hydraulic braking device.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an anti-wheel braking method and an anti-wheel braking device for an electric vehicle, which can solve the wheel locking problem only by torque control of an electric motor without attaching ABS to the hydraulic braking device.

In order to solve the above problems, the present invention provides a braking method for preventing a wheel from being locked during braking in an electric vehicle using hydraulic braking and regenerative braking, the method comprising the steps of: detecting a wheel speed and a wheel deceleration; Detecting a wheel-locked section in which the wheel deceleration during braking becomes equal to or higher than a limit level; And performing an anti-lock braking mode for controlling the torque of the electric motor so that a forward torque in an advancing direction of the vehicle is intermittently outputted from the electric motor driving the electric vehicle when the wheel locked section is detected. Thereby providing an anti-wheel braking method for an electric vehicle.

Preferably, the step of performing the anti-slip braking mode further includes the step of controlling the torque of the electric motor so that the forward torque is output from the electric motor in the vehicle traveling direction until the wheel speed reaches the target speed from the wheel speed zero A first control mode performing step of controlling the first control mode; And performing a second control mode performing step of controlling the torque of the electric motor so that the torque output in the electric motor is restricted until the wheel speed reaches zero at the target speed, when the wheel speed reaches the target speed, The first control mode performing step and the second control mode performing step may be alternately repeated until the vehicle speed becomes lower than the safe speed.

Preferably, the second control mode performing step controls the torque of the electric motor so that when the wheel speed reaches the target speed, the reverse torque is output in the direction opposite to the vehicle forward until the wheel speed reaches zero at the target speed Lt; / RTI >

Preferably, the anti-wheel braking method for an electric vehicle may gradually decrease the target speed during the repeating of the first and second control mode performing steps.

In order to solve the above problems, the present invention provides a braking device for preventing a wheel from being locked during braking in an electric vehicle using hydraulic braking and regenerative braking, the braking device comprising: a wheel speed detector for detecting a wheel speed and a wheel deceleration; A locked section detecting unit for detecting a wheel locked section in which the deceleration of the wheel during braking becomes equal to or more than a limit level; And a torque control section for controlling a torque of an electric motor for driving the electric vehicle, wherein the torque control section controls the torque of the electric motor so that the forward torque in the direction of travel of the electric motor is intermittently output when the wheel- The braking mode is the braking mode.

In order to achieve the above object, the present invention provides a computer-readable recording medium having recorded thereon a program for realizing the anti-wheel braking method for an electric vehicle.

According to the present invention, when a mechanical lock-up phenomenon occurs in a mechanical hydraulic braking apparatus, a short-time positive torque is intermittently output to an electric motor, thereby solving the wheel locking phenomenon of the mechanical hydraulic braking apparatus.

According to the present invention, it is possible to solve the wheel locking problem only by controlling the torque of the electric motor without mounting a separate wheel lock-up solenoid device such as ABS in the mechanical hydraulic braking device, so that miniaturization and cost reduction of the electric vehicle can be expected.

1 is a view illustrating occurrence of wheel lock in a vehicle;
2 is a block diagram of a wheel-lock braking device for an electric vehicle according to the present invention.
3 is a view showing a control operation according to the present invention from an initial stage of the electric vehicle starting to braking to a stop of the electric vehicle.
Fig. 4 is a view for explaining the control operation during the wheel-locked section in more detail; Fig.
FIG. 5 is a flow chart illustrating an anti-lock braking method for an electric vehicle according to the present invention. FIG.
6 is a flowchart showing a process of performing an anti-lock braking mode.

The present invention is capable of various modifications and various forms, and specific embodiments are illustrated in the drawings and described in detail in the text. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprising" or "having ", and the like, are intended to specify the presence of stated features, integers, steps, operations, elements, parts, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted as ideal or overly formal in meaning unless explicitly defined in the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

FIG. 1 is a view illustrating occurrence of wheel lock in a car. FIG.

       Slip ratio = (vehicle speed - wheel speed) / (wheel speed) * 100 (%)

The above equation is the expression of the slip rate.

The slip rate of 0% means that the wheel speed is the same as the vehicle speed, which means that the wheels of the car are moving without any locking phenomenon occurring.

A slip ratio of 100% means that the wheel speed is zero. When the slip ratio is 100%, the wheel speed becomes O, and the rotation of the wheel is stopped. However, since the vehicle can not completely stop, the wheel loses friction with the ground and slips and becomes unsteady. do. In case of falling into a state of inability to steer, there is a concern about an accident, and thus, the problem was solved by installing an anti-lock brake system (ABS).

FIG. 2 is a block diagram showing an anti-wheel braking apparatus for an electric vehicle according to the present invention.

Referring to FIG. 2, an anti-lock braking apparatus 100 for an electric vehicle according to the present invention includes a wheel speed detecting unit 110, a locked section detecting unit 120, and a torque control unit 130, 150).

The wheel speed detector 110 detects the wheel speed and the wheel acceleration, which are the wheel speeds of the electric vehicle. To detect the speed of the wheel, the wheel speed detecting unit 110 detects the number of revolutions of the wheel driving shaft and calculates the change in the number of revolutions of the wheel to detect the acceleration of the wheel.

The locked section detecting unit 120 analyzes the wheel speed and the wheel acceleration detected by the wheel speed detecting unit 110 and detects a wheel locking period in which the deceleration of the road speed at which the electric vehicle is braked becomes equal to or higher than the limit level.

As shown in FIG. 1, the vehicle deceleration from the point at which the wheel speed drops sharply is the wheel-locked section, and the deceleration of the vehicle, which means the degree of decrease in the wheel speed, becomes equal to or higher than the threshold level. The limit level can be set to various values depending on the characteristics of the vehicle and the brake, and the limit level can be determined within an appropriate range of 5 to 20 km / (hour * sec).

On the other hand, preferably the threshold level may be 10 km / (hour * sec). When the limit level is determined to be 10 km / (hour * sec), when the wheel deceleration becomes 10 km / (hour * sec) or more, the locking section detecting section 120 detects that the electric vehicle has reached the wheel locking section do.

When the wheel locked section is detected, the torque control section 130 controls the torque of the electric motor 140 driving the electric vehicle, thereby preventing the electric vehicle from falling into the unstable state when the electric vehicle is locked.

To this end, the torque control unit 130 controls the torque of the electric motor so that the forward torque is intermittently outputted in the vehicle traveling direction from the electric motor 140 driving the electric vehicle when the wheel-locked period is detected. In the present invention, the forward torque is output intermittently, which means that the electric motor 140 repeatedly outputs the pulse-like torque. That is, the torque control unit 130 controls the electric motor to output a pulse-like torque during the wheel-locked period in which the steering impossible state may occur.

On the other hand, the forward torque refers to the torque that causes the motor to be driven in the traveling direction of the vehicle, and the reverse torque refers to the torque that causes the motor to be driven in the reverse direction of the vehicle.

FIG. 3 is a view showing a control operation according to the present invention from the start to the stopping of the electric vehicle, and FIG. 4 is a view illustrating the control operation during the wheel-locked period in more detail.

The graph in FIG. 3 is a graph illustrating a case where a sudden stop attempt is made while the vehicle is running, and graphs for the wheel speed, the vehicle speed, the contact of the foot brake, the braking torque by the foot brake, .

When an abrupt stop is attempted by strongly depressing the foot brake during running of the electric vehicle, the contact of the foot brake is short-circuited so that hydraulic braking by hydraulic pressure and regenerative braking by electricity are also performed. During regenerative braking, the electric motor is controlled to output motor torque in the opposite direction of vehicle travel.

In the early stage of braking, braking is performed by using hydraulic braking and regenerative braking, and the speed of the vehicle is continuously decreased without occurrence of wheel locking due to the same wheel speed and vehicle speed.

However, at a certain moment, the wheel speed decreases sharply, and a wheel lock-in period starts which causes a difference between the wheel speed and the vehicle speed. It is necessary to prevent the wheel from being locked because the wheel slips in the locked position and the steering impossible state continues.

In order to prevent wheel locking, the torque control unit 130 controls the torque of the electric motor such that the forward torque in the vehicle traveling direction is output intermittently in a pulse shape as in the wheel-locked period of Fig.

Due to the intermittent forward motor torque in the form of a pulse, the wheel speed changes as shown in Fig. 3, and it is possible to prevent the vehicle from slipping due to wheel locking.

4 is a view for explaining the control operation during the wheel-locked period in more detail.

Referring to FIG. 4, graphs of the wheel speed of the wheel-locked section and the torque change of the electric motor are illustrated.

The time when the wheel speed is rapidly reduced and approximates to 0 is the time point of the wheel-locked period. The locked-period detecting unit 120 detects the wheel speed and the wheel acceleration to detect the wheel-locked period.

When the wheel locked section is sensed, the torque control section 130 performs the anti-lock braking mode for controlling the torque of the electric motor so that the positive torque is intermittently outputted from the electric motor in the vehicle traveling direction.

The anti-lock braking mode may include a first control mode (C1) and a second control mode (C2). As will be described later, the first control mode C1 is a mode for controlling the electric motor to output a forward torque, and the second control mode C2 is for controlling the electric motor to stop the torque output or to control the electric motor to output the reverse torque Mode.

The torque control unit 130 includes a first control mode execution unit 131 and a second control mode execution unit 132 for performing a first control mode and a second control mode, respectively.

The torque control unit 130 alternately and repeatedly performs the first control mode C1 and the second control mode C2 to prevent the steering failure state.

The present invention solves wheel locking phenomenon by installing an anti-lock brake system (ABS) or the like on a hydraulic braking device. However, according to the present invention, it is not necessary to add a separate anti-slip device such as ABS to a hydraulic braking device, It is possible to solve the problem that the wheel is locked only by the control.

Under the first control mode C1, the first control mode execution part 131 of the torque control part 130 controls the electric motor so that the forward torque is output, and the wheel speed accordingly increases.

The first control mode execution part 131 of the torque control part 130 stops the execution of the first control mode C1 when the wheel speed reaches the target speed V1. Then, the second control mode performing unit 132 of the torque control unit 130 performs the second control mode C2.

The second control mode C2 can control the torque of the electric motor in two different ways. One way is to control the torque output of the electric motor so that the torque is not outputted, and the other way is to control the output of the electric motor so that the motor torque is outputted in the opposite direction of the vehicle traveling direction, that is, in the reverse direction. In the present invention, any one of the two modes can be used as the second control mode C2.

When the second control mode C2 in which the motor torque is outputted in the reverse direction after the execution of the first control mode C1 is performed, there is an advantage that the durability of the mechanism including the drive shaft, wheels, hydraulic brakes, etc. is protected. On the other hand, when controlling the reverse motor torque to be output in the second control mode, the magnitude of the reverse torque can be appropriately determined at a torque magnitude in the range of 20 to 80% of the reverse torque at the initial stage of braking.

The second control mode execution unit 132 of the torque control unit 130 performs the second control mode from the time when the wheel speed becomes zero at the target speed. The period from when the wheel speed reaches the target speed to when the wheel deceleration becomes equal to or higher than the limit level can be determined as the period for performing the second control mode.

When the wheel speed reaches zero or the time when the wheel deceleration becomes equal to or higher than the limit level, the torque control unit 130 again performs the first control mode (C1).

Then, when the wheel speed reaches the target speed V2, the torque control section 130 stops the execution of the first control mode C1 and performs the second control mode C2.

As shown in FIG. 4, the torque controller 130 alternately repeats the first control mode C1 and the second control mode C2. The first and second control modes are performed in the first iteration period T1 and then the first and second control modes are performed in the second iteration period T2 and the second and third control modes are performed in the subsequent iteration periods T3 to Tn The alternate execution of the first and second control modes is repeated.

It is preferable that the target velocities V1 to Vn in the respective repeat periods T1 to Tn are gradually reduced for smooth deceleration and stop of the vehicle. In addition, the target velocities V1 to Vn in the respective repeat periods T1 to Tn may be determined differently depending on the characteristics of the vehicle, and preferably 50 to 95% of the target velocity in the previous repeat period.

Also, the torque control unit 130 controls the torque of the motor so that the pulse-shaped torque magnitude gradually decreases with time. The torque control unit 130 sets the initial forward torque magnitude to be equal to or similar to the reverse torque at the braking start and sets the magnitude of the initial forward torque to 50 to 95% of the forward torque magnitude in the immediately preceding interval in each of the repeated intervals T1 to Tn. . The magnitude of the initial forward torque and the torque magnitude in each iteration period (T1 to Tn) can be determined by various values depending on the type and characteristics of the electric vehicle.

On the other hand, when the target speeds V1 to Vn become lower than the safe speed, the torque control unit 130 completely stops the anti-lock braking mode. Here, various numerical values can be determined in the range of the safety speed of 5 to 20 km / hs, which is 10 km / hs.

Returning to Fig. 2, description will be made again.

The torque control unit 130 includes a first control mode execution unit 131 and a second control mode execution unit 132 that respectively perform the first control mode C1 and the second control mode C2, .

The inclination detection unit 150 detects the inclination of the electric vehicle and provides the detected inclination to the torque control unit 130.

The torque control unit 130 does not perform the anti-lock braking mode when the ascending slope of the electric vehicle is an uphill slope exceeding the threshold slope. In the case of an uphill with a large degree of inclination, the force of pulling back due to the influence of gravity becomes large. However, the uphill road having a gradient exceeding the threshold inclination does not cause the steering unavailability due to the locking of the wheel without performing the anti-lock braking mode. Here, it is preferable that the upward sloping limit is 3 to 20 degrees, which can be changed according to the characteristics of the electric vehicle.

It is preferable that the anti-wheel braking device for an electric vehicle according to the present invention is applied when the brakes used for hydraulic braking and the electric motor are connected to the same shaft. The problem of locking the wheel is solved by using the driving force of the electric motor. Therefore, the effect of the present invention can be achieved only when the hydraulic braking device and the electric motor are present on the same shaft.

Hereinafter, an anti-lock braking method for an electric vehicle according to the present invention will be described. The anti-lock braking method for an electric vehicle according to the present invention is substantially the same as the anti-lock braking device for an electric vehicle according to the present invention, and thus a detailed description and a duplicate description will be omitted.

5 is a flowchart illustrating an anti-lock braking method for an electric vehicle according to the present invention.

First, the wheel speed detecting section 110 detects the wheel speed (S10), and analyzes the change in the detected wheel speed to calculate the wheel acceleration (S20).

The locked section detection unit 120 analyzes the wheel speed and the wheel acceleration provided from the wheel speed detection unit 110 to determine whether the vehicle deceleration during braking of the electric vehicle is equal to or higher than the threshold level (S30). The point at which the wheel deceleration becomes above the limit level is the point where the wheel-locked section begins.

If the wheel deceleration is less than the threshold level, the torque control unit 130 controls not to perform the anti-lock braking mode (S70).

On the other hand, if the wheel deceleration is at the limit level, the tilt detection unit 150 detects the inclination of the vehicle and provides the detected tilt to the torque control unit 130 (S40). Of course, the tilt detection unit 150 may periodically detect the inclination of the vehicle and provide the result to the torque control unit 130. [

The torque control unit 130 controls the anti-lock braking mode so as not to perform the uphill when the inclination of the vehicle exceeds the threshold inclination (S70).

On the other hand, if the inclination of the vehicle is not an upward slope exceeding the threshold slope, the torque control unit 130 starts to perform the anti-slip braking mode (S60).

6 is a flowchart illustrating a process of performing the anti-lock braking mode.

First, the torque control section 130 controls the electric motor to be driven in the vehicle traveling direction by controlling the torque of the electric motor so that the forward torque in the vehicle traveling direction is outputted (S61).

The torque control unit 130 determines whether the wheel speed is equal to or higher than the target speed (S62).

When the wheel speed is less than the target speed, the torque control section 130 continues the step S61.

When the wheel speed becomes equal to or more than the target speed, the torque control section 130 stops driving the electric motor in the vehicle traveling direction (S63).

Steps S61 to S63 are the same as those of the first control mode described with reference to FIG.

On the other hand, when the wheel speed reaches the target speed, the torque control section 130 controls the torque of the electric motor so that the reverse torque in the opposite direction of the vehicle output is outputted, thereby controlling the electric motor to be driven in the opposite direction of the vehicle traveling direction (S64 ).

4, the torque control unit 130 may be controlled in such a manner as to limit the torque output of the electric motor so that the torque is not outputted.

The torque control unit 130 determines whether the wheel speed is zero (S65).

If the wheel speed is not zero, the torque control section 130 continues to step S64.

When the wheel speed becomes zero, the torque control section 130 decreases the target speed in the next iteration section (S66), and determines whether the target speed is equal to or less than the safe speed (S67).

When the target speed exceeds the safe speed, the process returns to step S61 for the repeated execution of the first control mode and the second control mode.

On the other hand, when the target speed is equal to or lower than the safe speed, the torque control section 130 stops performing the anti-lock braking mode.

Steps S64 to S65 are the same as those of the second control mode described with reference to FIG.

Meanwhile, the anti-wheel braking method for an electric vehicle according to the present invention is preferably applied to a case where a brake used for hydraulic braking and an electric motor are connected to the same shaft.

The method of the present invention can also be embodied as computer readable code on a computer readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like, and may be implemented in the form of a carrier wave (for example, transmission via the Internet) . The computer-readable recording medium may also be distributed over a networked computer system so that computer readable code can be stored and executed in a distributed manner.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, the scope of protection of the present invention should be construed in accordance with the following claims, and all technical ideas within the scope of equivalents and equivalents thereof should be construed as being covered by the scope of the present invention.

A wheel speed detecting unit 110, a locked section detecting unit 120
Torque control section, 130 electric motor, 140
An inclination detecting unit 150

Claims (12)

A braking method for preventing locking of a wheel during braking in an electric vehicle that uses hydraulic braking and regenerative braking but does not include an ABS (anti-lock brake system)
Detecting a wheel speed and a wheel deceleration;
Detecting a wheel-locked section in which the wheel deceleration during braking becomes equal to or higher than a limit level; And
And performing an anti-lock braking mode for controlling the torque of the electric motor so that a forward torque in an advancing direction of the vehicle is intermittently outputted from the electric motor driving the electric vehicle when the wheel locked section is detected. An anti - lock braking method for an electric vehicle. 2. The method of claim 1, wherein performing the anti-lock braking mode comprises:
A first control mode performing step of controlling the torque of the electric motor so that the forward torque is outputted from the electric motor in the vehicle traveling direction until the wheel speed reaches the target speed from the wheel speed zero position; And
Performing a second control mode execution step of controlling the torque of the electric motor so that the torque output in the electric motor is limited until the wheel speed reaches zero at the target speed, when the wheel speed reaches the target speed,
Wherein the first control mode performing step and the second control mode performing step are alternately repeated until the vehicle speed becomes less than the safe speed. 3. The method of claim 2, wherein the performing of the second control mode comprises:
And controlling the torque of the electric motor so that the reverse torque is outputted in the direction opposite to the vehicle forward until the wheel speed reaches zero at the target speed when the wheel speed reaches the target speed. Prevention braking method. 4. The method according to claim 2 or 3, wherein the anti-
And gradually decreasing the target speed during the repeating of the first and second control mode performing steps. The method as claimed in claim 1, wherein the anti-
Wherein the anti-slip braking mode is not performed for an ascending slope having an inclination greater than a threshold slope. The method as claimed in claim 1, wherein the anti-
Characterized in that the brake used for hydraulic braking and the electric motor are connected on the same axis. A braking device for preventing locking of a wheel during braking in an electric vehicle that uses hydraulic braking and regenerative braking but does not have an ABS (anti-lock brake system)
A wheel speed detector for detecting a wheel speed and a wheel deceleration;
A locked section detecting unit for detecting a wheel locked section in which the deceleration of the wheel during braking becomes equal to or more than a limit level; And
And a torque control unit for controlling a torque of an electric motor for driving the electric vehicle,
Wherein the torque control unit performs an anti-lock braking mode in which the torque of the electric motor is controlled so that a forward torque in an advancing direction of the vehicle is intermittently outputted from the electric motor when the wheel locked section is detected. Anti-lock braking device. 8. The braking system according to claim 7, wherein the anti-
A first control mode in which the torque of the electric motor is controlled so that the forward torque from the electric motor to the vehicle traveling direction is outputted until the wheel speed reaches the target speed from the wheel speed zero; And
And a second control mode for controlling the torque of the electric motor so that the torque output in the electric motor is limited until the wheel speed reaches zero at the target speed, when the wheel speed reaches the target speed,
Wherein the torque control unit alternately repeats the first control mode and the second control mode until the vehicle speed becomes lower than the safe speed. 9. The method according to claim 8,
Is a mode for controlling the torque of the electric motor so that the reverse torque is outputted in the direction opposite to the vehicle forward until the wheel speed reaches 0 at the target speed when the wheel speed reaches the target speed. Preventive braking device. 10. The torque converter according to claim 8 or 9,
Wherein the control unit gradually decreases the target speed during the repetition of the first control mode. The torque converter according to claim 7,
Characterized in that the anti-slip braking mode is not performed for an ascending slope having an inclination greater than a threshold slope. 8. The anti-wheel braking device for an electric vehicle according to claim 7,
Characterized in that the brake used for hydraulic braking and the electric motor are connected to the same axis.

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