KR20210025222A - Brake System for a Vehicle Rolling Tire by the Excitation of Normal Vibration - Google Patents

Abstract

A braking device using vertical vibration excitation in a tire of a traveling vehicle is provided. According to an embodiment of the present invention, a braking device effectively increases a kinetic friction force when a tire slips through a new braking method that applies vibration to the wheel to compensate for the alternating vertical drag acting between the tire and the road surface, thereby solving the problems of the braking force drop and the braking distance increase. Accordingly, it is possible to significantly reduce the incidence of accidents due to vehicle slipping, and to enable much safer driving through interaction with the existing brake system.

Description

Brake System for a Vehicle Rolling Tire by the Excitation of Normal Vibration}

The present invention relates to a vehicle braking device, and more particularly, to a vehicle braking device for improving the braking force of a vehicle on a slippery road surface.

In a wheel-rolled vehicle driving on slippery road surfaces such as snow, ice, frosty roads, muddy roads, and block roads wet with rain, if slipping occurs during braking, the braking force is reduced due to a very small dynamic coefficient of friction between the wheel and the ground surface. It becomes very small and the braking distance becomes longer. In addition, even if the braking force provided by the braking system of each wheel is the same, the amount of sliding of all the wheels is very slightly different on the contacting road surface, and accordingly, it becomes sensitive to very small steering changes, so it is easy to become in a state that cannot be controlled, leading to an accident. Can pose a risk.

In order to prevent this, a method of using an increase in the vertical drag component according to a small contact area by mounting a chain dedicated to snow roads on a tire or a snow tire having a thick groove has been widely used.

However, this has a hassle of having to install or replace each time during a snowfall or on the ice, it has to be operated only at a very low speed, and there are problems in that it does not effectively cope with the slip of the vehicle.

In order to shorten the braking distance on a slippery surface or during sudden braking, an electronic ABS (Anti-lock Brake System) is introduced into the vehicle wheel to provide a stopping friction force of more than 10 times per second during sudden braking, thereby increasing the braking force. have. However, under very slippery road conditions such as on snow, on ice, on sand, etc., even ABS is not helpful for accurate and quick braking.

The present invention was conceived to solve the above problems, and an object of the present invention is to improve the braking force of a vehicle through a new braking method that applies vibration to the wheels to compensate for the alternating current vertical drag acting between the tire and the road surface. It is to provide a braking device and a method that can be used.

According to an embodiment of the present invention for achieving the above object, a braking device includes: a first vibrator for generating vibration and applying the generated vibration to a wheel; And a controller for controlling the first vibrator to generate vibration during braking.

In addition, the first vibrator may apply vibration to compensate for an alternating current vertical drag acting between the tire of the wheel and the road surface.

In addition, the first vibrator may be installed in the housing of the shaft on which the wheel is mounted.

And, the vibration generated by the first vibrator may have a frequency band of 260 Hz to 500 Hz.

In addition, the vibration generated by the first vibrator may have a bandwidth of 120 Hz or less.

And, the vibration generated by the first vibrator may be a single frequency vibration or a multi-frequency vibration.

In addition, a first sensor for measuring the moving speed of the vehicle; further comprising, the controller may control the vibration generated by the first vibrator based on the moving speed of the vehicle measured by the first sensor.

In addition, the braking device according to an embodiment of the present invention may further include a second vibrator for applying vibration to cancel propagation of the vibration generated by the first vibrator toward the vehicle.

In addition, the braking device according to an embodiment of the present invention may further include a third vibrator for applying vibration to cancel propagation of the vibration generated by the first vibrator toward the vehicle.

In addition, the first vibrator may be installed on one side of the housing, and the second vibrator may be installed on one side of the housing and closer to the vehicle side than the first vibrator.

Further, the first vibrator may be installed on one side of the housing, and the third vibrator may be installed on the other side of the housing opposite to one side where the first vibrator is installed.

And, the braking device according to an embodiment of the present invention further comprises a second sensor for measuring the vibration propagated from the housing, the controller, based on the vibration measured by the second sensor, the second vibrator and Vibration generated by the third vibrator can be controlled.

Also, the wheel may be a wheel of a vehicle.

On the other hand, according to another embodiment of the present invention, a braking method includes the steps of controlling to generate vibration when braking a wheel; And applying the generated vibration to the wheel.

As described above, according to the embodiments of the present invention, through a new braking method that applies vibration to the wheel to compensate for the alternating current vertical drag acting between the tire of the wheel and the road surface, the kinetic friction force when the tire slip occurs is effectively increased. Thus, it is possible to solve the problem of lowering the braking force and increasing the braking distance.

According to the embodiments of the present invention, it is possible to significantly reduce the incidence of accidents due to slipping of a vehicle, and to enable a much safer driving through interaction with an existing brake system.

1 is a view provided for explanation of frictional force generated between a tire and a road surface;
2 is a view provided to explain the concept of a braking device according to an embodiment of the present invention;
3 is an example showing the overall frictional force reinforcement through dynamic frictional force compensation,
4 is a table showing the coefficient of friction,
Figure 5 A diagram showing the dynamic friction force acting between a vehicle tire and a road surface, and,
6 is a detailed configuration diagram of a braking device according to an embodiment of the present invention shown in FIG. 2.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

In an embodiment of the present invention, braking performance is improved through vertical vibration excitation in a tire of a vehicle running. Specifically, an embodiment of the present invention proposes a method of making the braking force on a slippery surface similar to that of a non-slip general road surface by applying a vertical vibration of a medium-high frequency band that the occupant does not feel to a vehicle wheel.

This creates a tangential resistance force of the tire by creating an additional dynamic normal force other than the dynamic load due to the dynamic movement of the existing vehicle's own weight according to the vibration excitation of a relatively high frequency, and in addition to the existing small kinetic friction force on the sliding tread, the tire and the tire It creates a resistance force that increases the traction between the road surfaces. That is, in the embodiment of the present invention, in order to improve the braking performance, vertical vibration between the tire and the contact surface is used.

1 is a view provided for explaining the frictional force generated between a tire and a road surface. The vertical drag acting between the road surface and the tire can be classified into DC and AC components, which act as a constant component and a variable component, that is, a dynamic friction force with respect to the time of the friction force, respectively.

는 F/N으로 주어지며, 전체 마찰력 F(t)는 다음의 식 (1)과 같이 일정한 평균 성분과 시간에 따라 변동하는 성분으로 각각 표현할 수 있다:Specifically, as shown in FIG. 1, when the smooth road surface and the tire of the vehicle contact each other and start a relative sliding motion, the frictional force generated on the contact surface appears as a constant average component over time and a component that fluctuates over time. do. The acting force that fluctuates with time is inherent in the motion mechanism itself, such as contact vibration, reciprocating excitation, or periodic excitation caused by surface roughness given in a magnitude relative to the vehicle's speed. When the average normal force is N and the average friction force is F, the average kinetic friction coefficient

Is given by F/N, and the total frictional force F(t) can be expressed as a constant average component and a component that fluctuates over time, as shown in the following equation (1):

(1)

(One)

로, 교류 성분은 순간 동마찰계수인

로 나타낸 일정한 상수의 마찰계수 값에 의해 결정된다. 한편, 일반 포장도로에서는

이므로, 식 (1)의 두번째 항은 무시가 가능하다. 또한, 눈밭이나 빙판, 서리 내린 길, 진흙탕 길 등과 같이 미끄러운 노면의 경우, 내재하는 왕복 운동형이나 주기적인 가진이 없으며, 또 조도가 매우 작으므로 표면 조도에 기인한 접촉 진동도 매우 작아서, 식 (1)의 두번째 항인 동적인 성분은 역시 무시할 수 있다. 따라서, 아래의 식 (2)와 같이 차량 전체의 무게에 해당하는 수직항력 N₀을 사용해 간략히 쓸 수 있다:The vertical drag in Equation (1) is the constant component N ₀ as direct current (DC) and the dynamic component f _N (t) as alternating current (AC), and the direct current component is the dynamic friction coefficient.

As, the alternating current component is the instantaneous dynamic friction coefficient

It is determined by the value of the coefficient of friction of a constant constant expressed as. On the other hand, on general paved roads

Therefore, the second term in Equation (1) can be ignored. In addition, in the case of slippery road surfaces such as snow fields, ice, frosty roads, muddy roads, etc., there is no inherent reciprocating motion or periodic excitation, and since the roughness is very small, the contact vibration caused by the surface roughness is very small. The dynamic component, which is the second term of 1), is negligible too. Therefore, it can be briefly written using _{the normal force N 0} corresponding to the weight of the vehicle as shown in Equation (2) below:

(2)

(2)

In the case of the slippery road mentioned above, the average coefficient of dynamic friction between the tire and the road surface is about 0.02-0.05 when the slip ratio λ is 25% or more, about 0.02-0.05 in the case of ice or frosty roads, and about 0.1-0.15 in the case of snow fields. Compared to the average dynamic friction coefficient of 0.4-0.9 that occurs on general asphalt or concrete road surfaces, this is very small, which means that it can cause a big problem in braking performance when braking the vehicle being driven. Here, the slip ratio is given by the following equation (3) in SAE J670, assuming that the degree of dependence of the vehicle is V, the wheel rotational speed is Ω, and the radius of the wheel at the center of the wheel in an unloaded state is R:

(3)

(3)

If the static weight or dynamic friction component increases to compensate for equation (2), the overall friction force increases as in equation (1), so that even on slippery roads, it is as if braking on ordinary asphalt or concrete roads, or less slippery. Can be. In general, static weight cannot be significantly increased, so the method of applying artificial alternating current to the tire from the outside remains, and given such an alternating current or oscillating type, that is, external vibratory excitation f _v , the following It will be possible to increase the magnitude of the dynamic friction force as shown in equation (4):

(4)

(4)

는 이제 요동형 동마찰계수(oscillatory kinetic friction coefficient)라고 부를 수 있다.here,

Can now be called oscillatory kinetic friction coefficient.

An excitation system for obtaining such an additional dynamic friction force can be implemented as shown in FIG. 2. 2 is a view provided to explain the concept of a braking device according to an embodiment of the present invention.

A braking device according to an embodiment of the present invention, as shown in FIG. 2, includes an actuator-1 (110), an exciter-2 (120) and an exciter-3 (130). . The exciters 110, 120, and 130 are installed in the housing 30 of the shaft (drive shaft or axle shaft) 20 on which the wheel 10 is mounted.

The vibrator-1 (110) is a vibrator that applies vibration to the wheel 10 to compensate for the alternating vertical drag acting between the tire of the wheel 10 and the road surface.

Vibration generated by the vibrator-1 (110) and transmitted to the tire of the wheel 10 increases the alternating current component of the vertical drag force to enhance the dynamic friction force, thereby increasing the friction force between the tire and the road surface.

The vibrator-2,3 (120,130) is a vibrator that applies vibration to offset the propagation of the vibration generated from the vibrator-1 (110) to the vehicle side, not to the wheel (10), specifically to other parts inside the vehicle body. admit.

The vibrator-2(120) is installed on the side of the vibrator-1(110), and is installed closer to the vehicle side than the vibrator-1(110). That is, as shown in Fig. 2, the vibrator-1 (110) and the vibrator-2 (120) are installed adjacent to one side of the housing (30), the vibrator-1 (110) is a wheel (30) The vibrator-2 120 is installed in a position close to and in a position close to the vehicle, respectively.

The vibrator-3 (130) is installed on the other side of the housing (30) opposite to one side of the housing (30) in which the vibrator-1 (110) is installed.

3 is an example showing the reinforcement of the total friction force through dynamic friction force compensation. When the dynamic component of the frictional force is strengthened, the energy of the frictional force is directly related to the square of the envelope of the entire shape, so that the gain of the total frictional force due to the strengthening of the dynamic frictional force component and its prediction are possible.

In (a) of FIG. 3, the friction force generated on the tire and the slippery road surface and the dynamic friction force is compensated through vibration of the vibrator and the envelope thereof, and the effective value of the friction force is shown in (b) of FIG. 3, respectively.

"는 타이어-빙판 사이의 마찰력을, "

"는 가진기의 진동으로 생긴 요동형 저항에 의한 마찰력 성분을, "

"는 요동형 저항에 의한 마찰력의 envelope을, "

"은 경질고무-유리(타이어-빙판을 모사) 간 마찰력의 실효값을, "

"은 요동형 저항에 의한 마찰력의 envelope에 의한 동적 마찰력 성분이 기존의 경질고무-유리 간의 동마찰력에 보상된 최종적인 동마찰력의 실효값을 각각 나타내었다.In Fig. 2 "

"Is the friction between the tire and ice,"

"Is the frictional force component due to the oscillating resistance caused by the vibration of the vibrator,"

"Is the envelope of the frictional force by oscillating resistance,"

"Is the effective value of the frictional force between hard rubber and glass (which simulates tire and ice),"

"Represents the effective value of the final dynamic friction force in which the dynamic friction force component due to the envelope of the friction force caused by the oscillating resistance is compensated for the existing dynamic friction force between hard rubber and glass.

In FIG. 3, when a hard rubber is rubbed against a slippery surface such as glass (simulation of friction between a slippery road surface and a tire), the experimental results show how the dynamic friction is increased by this method. The hard rubber used in the experiment has a value of 73 Shore hardness. Considering that the Shore hardness of rubber used for tire tread is approximately 65-70, it can be said to be a similar material.

In addition, as shown in the table of Fig. 4, since the coefficient of dynamic friction between ice and rubber is known to be about 0.15, the result of Fig. 3 showing the case between the hard rubber and the clean glass surface is the coefficient of dynamic friction between the frozen road surface and the running tire. It can be said to be a very similar case.

In contrast, the coefficient of dynamic friction between the tire and the dry general asphalt road surface is a very large value of 0.5-0.8. 5 schematically shows when this situation is applied to an actual vehicle. The left side of FIG. 5 shows the dynamic friction force acting between the vehicle tire running on the slippery road surface and the road surface, and the right side of FIG. 5 shows the principle of FIG. 3 using the vertical vibration of an external input exciter connected to the wheel under the same conditions. The dynamic friction force compensated by is shown.

As a simple example, it is possible to think of a method of giving the axle vibration of a sine wave having a constant amplitude, but when the vibration frequency is low, the positive phase and the negative phase of the vibration move the vehicle. Compared to the speed, it is well distinguished, so if you take an average over a certain period of time, it can be said that there is no overall benefit. For example, a vehicle driving or sliding at a speed of 20 kph per second moves 5.6 m per second, but if excitation is performed with a low frequency vibration of 56 Hz, it corresponds to one cycle per 0.1 m, increasing and decreasing the average vertical force of RMS every 5 cm. As a result, there is no significant benefit in generating frictional force. In addition, at low frequencies, when external excitation for compensating the friction force is given, the occupant feels vibration in the band of about 35-500 Hz, so even if there is a benefit of braking accordingly, practical application becomes difficult. On the other hand, it can be noted that humans feel the touch vibration most sensitively to vibrations of about 200-250Hz on average.

Although it is possible to use excitation of less than 250Hz, it can be a new vibration-noise source if the residual vibration is transmitted to the chassis and body, if it matches the structure of various parts, the body panel, and the resonance of the interior space. Be careful. In addition, since the structural resonance of the tire itself appears prominently in the range of about 80-260 Hz, excitation using this band has the potential to have a great influence on driving stability and ride comfort. It is possible to use a frequency of about 500Hz or more that humans cannot feel, but the higher the excitation frequency, the worse the efficiency of the energy input to the exciter, and thus the controllable excitation power decreases. You can say no. In addition, since the center peaks of air and rescue aircraft noise due to the tire structure are usually in the 700-1300 Hz band, excitation of about 600 Hz or more can be said to be negative in terms of noise-vibration.

Accordingly, in summarizing the above, it is recommended to use a frequency of about 300-400Hz or more when using a vibration damper together, but in the case of offset control, it can be said that any frequency between 260-500Hz can be used. Meanwhile, the 260-500Hz band corresponds to the mid-high frequency in terms of vibration of the vehicle body, suspension system, other chassis watches, and tires, which means that there are many related vibration modes.

Therefore, it becomes difficult to avoid large resonance of a specific part even if it is excitation at any pure tone frequency. On the other hand, when several different frequencies are together at almost the same energy level or a bandwidth excitation having a specific bandwidth is performed, the negative effect is reduced due to the effect of interference between several resonance modes (smearing effect). ). Considering the energy efficiency of excitation, narrow-band excitation is more advantageous than broadband excitation, so narrow-band excitation or multi-frequency excitation with a bandwidth less than 100-120Hz within the 260-500Hz frequency band. You can see that it is appropriate.

In the case of a multi-frequency excitation, which is regarded as medium-high frequency in terms of vibration, the energy provided by the vertical force is the envelope or root-mean-square (RMS) of the entire input waveform over time rather than individual vibration waveforms. It is closely related. The envelope of the oscillating signal is represented by a smooth chain of the largest amplitudes, and the time fluctuation is generally very slow. In the case of mid- and high-frequency vibrations, especially in the case of complex multi-frequency vibrations in these frequency bands, the amplitude that produces the corresponding energy is not the individual signals that make up the entire waveform, but the size of the envelope representing the variation of the entire waveform. Complying is a widely known fact in terms of verbal communication and grasping the size and characteristics of musical instruments. In the case of a signal in which simple harmonic oscillations are continuously overlapped (~e ^jωt ), it can be expressed as Equation (5) below:

(5)

(5)

), ω는 각주파수(angular frequency; rad/s), c_ph는 파동의 위상속도(phase velocity), f(k)는 초기 변위에 대한 푸리에 변환값(Fourier transform)을 나타낸다. 이러한 복합 요동을 총괄적으로 나타내는 해는 수학적으로 정상위상법 (method of stationary phase)에 의해 아래의 식 (6)과 같이 얻어진다:Here, k is a wave number;

), ω is the angular frequency (rad/s), c _ph is the phase velocity of the wave, and f(k) is the Fourier transform for the initial displacement. The solution representing these complex fluctuations as a whole is mathematically obtained by the method of stationary phase as shown in Equation (6) below:

(6)

(6)

According to the steady phase condition, the following equation (7) becomes:

(7)

(7)

Here, c _g means the group velocity at which energy is propagated. The physical meaning of equations (6) and (7) is that _{narrow-band fluctuations composed of multiple frequencies with ω 0} as the center frequency have an amplitude that fluctuates with time as a whole, and the amplitude changes due to each fluctuation in the band. Rather, it indicates that the total amplitude is determined according to the group velocity fluctuation at the center frequency representing the entire band, which means the envelope of the waveform. Since the group velocity corresponds to the propagation velocity of energy, the envelope expression for the total bandwidth fluctuation given in Equation (6) means the equivalent excitation amplitude that can be expressed as energy by squaring.

In actual data processing, a representative signal processing technique for extracting the envelope of the signal is expressed as the size of the analytic signal obtained as a result of the Hilbert transform as shown in the following equation (8-9):

(8)

(8)

(9a,b)

(9a,b)

는 x(t)의 Hilbert transform 결과이며, A(t)와 θ(t)는 각각 해석적 신호의 크기와 위상으로, 물리적인 의미로는 x(t)의 envelope와 순간 위상을 의미한다. 위의 식 (8-9)에서, 신호

은 해당하는 수직력 혹은 가속도와 관련된 변수라고 생각할 수 있다. 마찰력은 수직항력에 비례하므로, 이러한 요동에 의해 생기는 마찰력은 진동 가속도 envelop에 비례하게 된다. 또, 물리계의 에너지 값은 관련된 계측 물리변수의 제곱에 비례하므로, 식 (9)에 의하면 특정 시간에서 envelope의 크기 A는 신호의 파워, 즉 에너지와 직접 관련된다. 이 에너지는 envelope의 해석으로부터 얻어지는 군속도(group velocity)를 따라 전달된다.Where z(t) is the analytic signal of x(t),

Is the Hilbert transform result of x(t), and A(t) and θ(t) are the magnitude and phase of the analytic signal, respectively, and in the physical sense, the envelope and instantaneous phase of x(t). In the above equation (8-9), the signal

Can be thought of as a variable related to the corresponding normal force or acceleration. Since the frictional force is proportional to the normal force, the frictional force generated by this oscillation is proportional to the vibration acceleration envelope. In addition, since the energy value of the physical system is proportional to the square of the related measured physical variable, according to Equation (9), the size A of the envelope at a specific time is directly related to the power of the signal, i. This energy is transferred along the group velocity obtained from the interpretation of the envelope.

Therefore, by using the envelope of vibration acceleration, it is possible to know the magnitude and transmission pattern of the energy of the oscillating signal, and according to the same principle, it is possible to predict or evaluate the frictional force increased by the application of vertical vibration. In this way, when a composite vibration of medium-high frequency is applied to a tire grounded on the ground, additional frictional force is generated in the existing kinetic friction given by the existing ground and the tire material and the relative speed.

6 is a detailed configuration diagram of a braking device according to an embodiment of the present invention shown in FIG. 2. A braking device according to an embodiment of the present invention, as shown in Fig. 6, is a vibration sensor (Vibrometer) (110, 120, 130), a speed sensor (Velocity sensor) 140, a force sensor (Force sensor) 150, a vibration sensor (Vibrometer). ) 160, an exciter driver 170, and a power supply 180.

Since the exciters 110, 120, and 130 have been described in detail with reference to FIG. 2, descriptions thereof will be omitted here.

The speed sensor 140 measures the moving speed of the vehicle, the force sensor 150 measures the magnitude of vibration applied by the vibrator-1 (110), and the vibration sensor 160 is equipped with a wheel 10 The vibration in the housing 30 of the shaft (drive shaft or axle shaft) 20 is measured. The measurement result by the sensors 140, 150, and 160 is transmitted to the exciter driving unit 170.

The exciter driver 170 includes a data memory 171, a controller 172, and an amplifier 173.

The data memory 171 stores the measurement results by the sensors 140, 150, and 160 as data. The controller 172 generates a control signal for controlling the exciters 110, 120, and 130 based on the data stored in the data memory 171, amplifies it through the amplifier 173, and applies it to the exciters 110, 120, and 130.

Specifically, the controller 172 generates a control signal for generating a vibration for performing a speed control corresponding to the vehicle speed measured by the speed sensor 140 when the slipping motion of the tire occurs. 110).

The excitation signal of the exciter-1 (110) is suitable for single-frequency narrow-band excitation or multi-frequency excitation with a bandwidth less than 100-120 Hz within the 260-500 Hz frequency band, and the specific excitation value is determined by the vehicle speed. .

At this time, the controller 172 detects the vibration state of the vibrator-1 110 measured by the force sensor 150, and feedback control is possible.

In addition, the controller 172 generates control signals for generating vibration capable of canceling the vibration in the housing 30 measured by the vibration sensor 160, and the vibrator-2 120 and the vibrator- Control 3(130).

The power supply 180 supplies necessary power to the exciters 110, 120 and 130, the sensors 140, 150 and 160, and the exciter driving unit 170.

Until now, a preferred embodiment has been described in detail with respect to a braking device using vertical vibration excitation in a tire of a traveling vehicle.

In the above embodiment, the housing 30 of the shaft 20 on which the wheel 10, which is the position where the vibrators 110, 120, and 130 are installed, is only exemplary. It goes without saying that it is possible to position the vibrators 110, 120, and 130 at different positions according to the structure, shape, and type of the vehicle dynamometer.

In addition, in the above embodiment, the vibrator-2 (120) and the vibrator-3 (130) correspond to an optional configuration. Even in the case of implementing a braking device excluding at least one of these, the technical idea of the present invention may be applied.

Further, in the case of an electric vehicle, it goes without saying that the technical idea of the present invention can be applied to the case of controlling excitation and vibration at a position where the electric motor is attached. Furthermore, the technical idea of the present invention can be applied to a drive system other than a vehicle.

In addition, although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention belongs without departing from the gist of the present invention claimed in the claims. In addition, various modifications are possible by those of ordinary skill in the art, and these modifications should not be understood individually from the technical spirit or prospect of the present invention.

10: wheels
20: shaft (drive shaft or axle shaft)
30: housing
110: Actuator-1
120: exciter-2
130: exciter-3
140: Velocity sensor
150: Force sensor
160: Vibrometer
170: exciter drive unit
171: data memory
172: controller
173: amplifier
180: power supply

Claims (14)

A first vibrator for generating vibration and applying the generated vibration to the wheel; And
And a controller for controlling the first vibrator to generate vibration during braking.
The method according to claim 1,
The first exciter,
A braking device, characterized in that it applies vibration to compensate for alternating vertical drag acting between the tire of the wheel and the road surface.
The method according to claim 1,
The first exciter,
Braking device, characterized in that it is installed in the housing of the shaft on which the wheel is mounted.
The method of claim 3,
The vibration generated by the first vibrator is,
Braking device, characterized in that the frequency band is within the range of 260Hz to 500Hz.
The method of claim 4,
The vibration generated by the first vibrator is,
Braking device, characterized in that the bandwidth is within 120Hz.
The method of claim 5,
The vibration generated by the first vibrator is,
Braking device, characterized in that the single frequency vibration or multi-frequency vibration.
The method according to claim 1,
Further comprising a; a first sensor for measuring the moving speed of the vehicle,
The controller,
A braking device, characterized in that, based on the moving speed of the vehicle measured by the first sensor, the vibration generated by the first vibrator is controlled.
The method according to claim 1,
And a second vibrator for applying vibration to cancel propagation of the vibration generated in the first vibrator toward the vehicle.
The method of claim 8,
And a third vibrator for applying vibration to cancel propagation of the vibration generated in the first vibrator toward the vehicle.
The method according to claim 8 or 9,
The first exciter,
It is installed on one side of the housing,
The second exciter,
Braking device, characterized in that installed at a position closer to the vehicle side than the first vibrator on one side of the housing.
The method of claim 10,
The first exciter,
It is installed on one side of the housing,
The third exciter,
A braking device, characterized in that it is installed on the other side of the housing opposite to the one side where the first vibrator is installed.
The method of claim 10,
Further comprising a; a second sensor for measuring the vibration propagated in the housing,
The controller,
A braking device, characterized in that, based on the vibration measured by the second sensor, the vibration generated by the second and third vibrators is controlled.
The method according to claim 1,
The wheel,
Braking device, characterized in that the wheel of a vehicle.
Controlling to generate vibration when braking the wheel; And
Applying the generated vibration to the wheel; braking method comprising a.

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