Device and method for controlling shock absorption force by road frequency classification

Abstract

The present invention relates to an apparatus and method for controlling damping force by road frequency classification. An apparatus for controlling damping force by road frequency classification may include: a high-pass filter configured to perform high-pass filtering on a detection value of wheel vibration input from a wheel vibration sensor according to different cutoff frequencies; a main frequency extraction module configured to determine a main frequency of wheel vibration according to a filter value output from the high-pass filter; a maximum amplitude and amplitude ratio extraction module configured to determine a maximum amplitude and amplitude ratio of wheel vibration based on the filter value; a road grip control determination module configured to determine whether to control road grip according to a determined main frequency and a determined maximum amplitude and amplitude ratio; and a shock absorber control module configured to determine a damping force of a shock absorber of a vehicle according to a determination result and road surface roughness.

Description

Technical Field

[0001] The present invention relates to a device and method for controlling damping force by classifying road frequencies, and more specifically, to a device and method for controlling damping force, which can classify road frequencies using information detected by wheel vibration sensors arranged on wheels of a vehicle to detect longitudinal acceleration of the wheels, and appropriately control the damping force of the vehicle's shock absorber based on the classified road frequencies to improve the vehicle's ride comfort and its road grip. Background Art

[0002] The electronically controlled suspension ECS currently applied to vehicles has a shock absorber configured to control the vibration of the spring when the spring is impacted by speed bumps, rapid acceleration, rapid deceleration, cornering, etc., so as to reduce the impact transmitted from the road to the vehicle body, thereby improving ride comfort.

[0003] As one of the conventional shock absorber control technologies, there is a known sky-hook control method, in which a body vibration sensor provided on the vehicle body and a wheel vibration sensor provided on the wheel are used to detect the longitudinal acceleration of the vehicle body and the longitudinal acceleration of the wheel, the longitudinal velocity of the vehicle body and the longitudinal velocity of the wheel are obtained by integrating the respectively detected longitudinal accelerations, and the damping force of the shock absorber is controlled based on the difference between the longitudinal velocity of the vehicle body and the longitudinal velocity of the wheel.

[0004] However, the current shock absorber control technology based on skyhook control is implemented based on driving on a flat road (e.g., a paved road), and therefore, when the vehicle is driving on an uneven road, the ride comfort or road grip of the vehicle may deteriorate. For example, a vehicle intended to perform dynamic and high-speed driving maintains a hard state, in which the damping force of the shock absorber is reduced. In this case, such shock absorber control technology is advantageous in optimizing handling and vehicle motion control on a flat road, but may reduce the ride comfort and the road grip of the vehicle on an uneven road, thereby causing instability in vehicle driving.

[0005] The information included in this Background section of the present invention is only intended to enhance understanding of the general background of the present invention and should not be taken as an acknowledgement or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0006] Various aspects of the present invention are directed to providing a device and method for controlling damping force, which can classify road frequencies using information detected by wheel vibration sensors arranged at wheels of a vehicle to detect the longitudinal acceleration of the wheels, and control the damping force of the vehicle shock absorber based on the classified road frequencies to be suitable for road conditions to improve the ride comfort of the vehicle and its road grip.

[0007] According to various aspects of the present invention, the above and other purposes can be achieved by providing a device for controlling the damping force by road frequency classification, the device comprising: a plurality of high-pass filters, the high-pass filters being configured to perform high-pass filtering on the detection values ​​of the wheel vibration input from the wheel vibration sensor according to different cut-off frequencies; a main frequency extraction module being configured to determine the main frequency of the wheel vibration according to a plurality of filter values ​​output from the high-pass filter; a maximum amplitude and amplitude ratio extraction module being configured to determine the maximum amplitude and amplitude ratio of the wheel vibration according to the filter values ​​output from the high-pass filter; a road grip control determination module being configured to determine whether to control the road grip according to the determined main frequency of the wheel vibration and the determined maximum amplitude and amplitude ratio of the wheel vibration; and a shock absorber control module being configured to determine the damping force of the shock absorber of the vehicle according to the determination result of the road grip control determination module and the road surface roughness.

[0008] The main frequency extraction module may include: a plurality of zero-crossing counters, each of which is configured to count the number of times a filter value output from a corresponding one of the high-pass filters crosses zero "0"; a plurality of integrators, each of which is configured to accumulate and sum the count values, the count values ​​being obtained by counting by a corresponding one of the zero-crossing counters within a predetermined sampling time; a plurality of counting and output units, each of which is configured to update and output a count sum at each sampling time, the count sum being obtained by accumulating and summing the count values ​​by a corresponding one of the integrators; a body resonance region summing calculator, which is configured to sum the count sums corresponding to the body resonance region of the vehicle among the count sums output from the plurality of counting and output units; a wheel resonance region summing calculator, which is configured to sum the count sums corresponding to the wheel resonance region of the vehicle among the count sums output from the plurality of counting and output units; and a main frequency calculator, which is configured to derive the main frequency of wheel vibration according to a difference between the sum of the count sums corresponding to the body resonance region of the vehicle and the sum of the count sums corresponding to the wheel resonance region of the vehicle.

[0009] The main frequency calculator may derive the main frequency by dividing a difference between a sum of counts corresponding to the vehicle body resonance region and a sum of counts corresponding to the wheel resonance region by twice a predetermined sampling time.

[0010] The maximum amplitude and amplitude ratio extraction module may include: a plurality of absolute value calculators, each of which is configured to determine the absolute value of a corresponding one of the filtered values; a plurality of maximum value calculators, each of which is configured to determine the maximum value of the absolute values ​​determined by the corresponding one of the absolute value calculators; a plurality of maximum value determiners, each of which is configured to update and output the maximum value determined by the corresponding one of the plurality of maximum value calculators at each predetermined sampling time; a body resonance region summing calculator, which is configured to sum the maximum values ​​corresponding to the body resonance region of the vehicle among the maximum values ​​output from the maximum value determiners; a wheel resonance region summing calculator, which is configured to sum the maximum values ​​corresponding to the wheel resonance region of the vehicle among the maximum values ​​output from the maximum value determiners; a maximum amplitude calculator, which is configured to determine the maximum amplitude of the wheel vibration according to the difference between the sum of the maximum values ​​corresponding to the body resonance region of the vehicle and the sum of the maximum values ​​corresponding to the wheel resonance region of the vehicle; and an amplitude ratio calculator, which is configured to determine the amplitude ratio of the wheel vibration according to the ratio of the sum of the maximum values ​​corresponding to the body resonance region of the vehicle and the sum of the maximum values ​​corresponding to the wheel resonance region of the vehicle.

[0011] When the main frequency of the wheel vibration determined by the main frequency extraction module is greater than a first predetermined reference value, the maximum amplitude of the wheel vibration determined by the maximum amplitude and amplitude ratio extraction module is less than a second predetermined reference value, and the amplitude ratio of the wheel vibration determined by the maximum amplitude and amplitude ratio extraction module is greater than a third predetermined reference value, the road grip control determination module determines that the road grip is to be controlled.

[0012] When the road grip control determination module determines that the road grip is to be controlled and the road surface roughness is greater than a fourth predetermined reference value, the damping force of the damper control module may change the damping force of the damper to a hard state in which the damping force is reduced.

[0013] When the road grip control determination module determines that the road grip is not to be controlled and the road surface roughness is not greater than a fourth predetermined reference value, the damping force of the damper control module may change the damping force of the damper to a hard state in which the damping force is reduced.

[0014] When the road grip control determination module determines that the road grip is not to be controlled and the road surface roughness is greater than a fourth predetermined reference value, the damping force of the damper control module may change the damping force of the damper to a soft state in which the damping force is increased.

[0015] According to another aspect of the present invention, a method for controlling shock absorbing force by road frequency classification is provided, the method comprising: performing high-pass filtering on the detection value of wheel vibration input from the wheel vibration sensor according to different cut-off frequencies; determining the main frequency of the wheel vibration according to the filter values ​​output from multiple high-pass filters; determining the maximum amplitude and amplitude ratio of the wheel vibration according to the filter values ​​output from the high-pass filter; determining whether to control road grip according to the determined main frequency of the wheel vibration and the determined maximum amplitude and amplitude ratio of the wheel vibration; and determining the shock absorbing force of the vehicle's shock absorber according to the determination result of whether to control road grip and the road surface roughness.

[0016] The methods and apparatus of the present invention have other features and advantages that will be apparent from, or will be described in detail in, the accompanying drawings and subsequent specific embodiments incorporated herein, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a perspective view exemplarily showing one example of a vehicle to which an apparatus and method for controlling a damping force by road frequency classification according to various exemplary embodiments of the present invention are applied;

[0018] Figure 2 is a schematic diagram showing the relationship between the frequency of a detection value detected by a wheel vibration sensor of a vehicle and the vibration of the vehicle according to a constant of a shock absorber;

[0019] Figure 3 is a block diagram of an apparatus for controlling damping force by road frequency classification according to various exemplary embodiments of the present invention;

[0020] Figure 4 is a flowchart illustrating a method for controlling a damping force according to various exemplary embodiments of the present invention;

[0021] Figure 5 is a block diagram showing a detailed configuration of a high-pass filter component of an apparatus for controlling a damping force according to various exemplary embodiments of the present invention;

[0022] Figure 6 is a block diagram illustrating in more detail a portion of a main frequency extraction module of an apparatus for controlling a damping force according to various exemplary embodiments of the present invention;

[0023] Figure 7 is a block diagram illustrating in more detail the remaining portion of a main frequency extraction module of an apparatus for controlling damping force according to various exemplary embodiments of the present invention;

[0024] Figure 8 is a block diagram illustrating in more detail a portion of a maximum amplitude and amplitude ratio extraction module of an apparatus for controlling damping force according to various exemplary embodiments of the present invention; and

[0025] Fig. 9 is a block diagram illustrating the rest of the maximum amplitude and amplitude ratio extraction module of the apparatus for controlling damping force according to various exemplary embodiments of the present invention in more detail.

[0026] It should be understood that the accompanying drawings are not drawn to scale, but are illustrative and simplified to present various features to show the basic principles of the present invention. The specific design features of the present invention contained herein (including, for example, specific size, direction, position and shape) will be determined in part by the specific environment to be applied and used.

[0027] In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. DETAILED DESCRIPTION

[0028] Various embodiments of the present invention will now be shown in detail, and the examples of these embodiments are shown in the accompanying drawings and are described as follows. Although the present invention will be described in conjunction with exemplary embodiments of the present invention, it should be understood that this specification is not intended to limit the present invention to those exemplary embodiments. On the other hand, the present invention is intended to not only cover exemplary embodiments of the present invention, but also cover various alternatives, modifications, equivalents and other embodiments that may be included in the spirit and scope of the present invention as defined by the appended claims.

[0029] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Throughout the drawings, the same reference numerals will be used wherever possible to refer to the same or like parts.

[0030] Hereinafter, an apparatus and method for controlling damping force through road frequency classification according to various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0031] Figure 1 is a perspective view exemplarily illustrating one example of a vehicle to which an apparatus and method for controlling a damping force through road frequency classification according to various exemplary embodiments of the present invention are applied.

[0032] Reference Figure 1A vehicle 10 to which the apparatus and method for controlling a damping force according to various exemplary embodiments of the present invention are applied may include wheel vibration sensors 11a and 11b, body vibration sensors 12a, 12b and 12c, shock absorbers 13a, 13b, 13c and 13d, and an electronic control unit (ECU); the wheel vibration sensors 11a and 11b are provided at wheels of the vehicle to detect vibrations of the wheels; each of the body vibration sensors 12a, 12b and 12c is installed in an area of ​​the vehicle body to detect vibrations of the vehicle body; the shock absorbers 13a, 13b, 13c and 13d are provided at respective wheels of the vehicle so that the damping force of the respective wheels is adjustable; the electronic control unit (ECU) is configured to determine and adjust the damping force of the shock absorbers 13a, 13b, 13c and 13d based on detection values ​​of the wheel vibration sensors 11a and 11b and the body vibration sensors 12a, 12b and 12c.

[0033] The wheel vibration sensors 11a and 11b and the vehicle body vibration sensors 12a, 12b, and 12c may be implemented as gyro sensors that detect the longitudinal acceleration of the vehicle, and the number of the wheel vibration sensors and the vehicle body vibration sensors may be appropriately adjusted when necessary.

[0034] The shock absorbers 13a, 13b, 13c and 13d adjust the flow rate of oil supplied to the shock absorbers by valves whose openings are controlled by electric currents, and accordingly, the shock absorbing forces of the shock absorbers 13a, 13b, 13c and 13d can be determined.

[0035] ECU 20 can receive detection values ​​from wheel vibration sensors 11a and 11b and vehicle body vibration sensors 12a, 12b and 12c, and accordingly determine the amount of current (current value) supplied to shock absorbers 13a, 13b, 13c and 13d. ECU 20 can supply the determined current value to shock absorbers 13a, 13b, 13c and 13d, thereby adjusting the damping force of shock absorbers 13a, 13b, 13c and 13d.

[0036] Figure 2 1 is a diagram showing a relationship between the frequency of a detection value detected by a wheel vibration sensor of a vehicle and the vibration of the vehicle according to a constant of a shock absorber. Figure 2 The illustrated diagram shows information on the road grip determined as the wheel vibration, and it should be understood that as the wheel vibration increases, the road grip relatively decreases.

[0037] exist Figure 2In the figure, the reference symbol "FH" indicates the case where the shock absorber constant has a minimum value, that is, the shock absorbing force of the shock absorber is minimized and the spring installed on the shock absorber is in the hardest state, and the reference symbol "FS" indicates the case where the shock absorber constant has a maximum value, that is, the shock absorbing force of the shock absorber is maximized and the spring installed on the shock absorber is in the softest state.

[0038] like Figure 2 As shown, the vibration intensity when the spring is set to the hardest state and when the spring is set to the softest state are different in the regions R1 to R4 divided based on the vibration frequency.

[0039] First, in region R1 corresponding to a flat road driving section with a low level of wheel vibration, the vibration intensity when the spring is set to the softest state is higher than the vibration intensity when the spring is set to the hardest state, and it can be determined that resonance occurs at a specific frequency when the spring is set to the softest state. This resonance can be considered as a vehicle body resonance occurring in the low-frequency domain. Therefore, in region R1, when the spring is set to the hardest state by minimizing the damping force of the shock absorber, excellent road grip can be ensured.

[0040] Furthermore, among the regions R2 to R4 (i.e., corresponding to the uneven road driving section) where the wheel vibrates, in the region R2, the vibration intensity when the spring is set to the hardest state is higher than the vibration intensity when the spring is set to the softest state. Therefore, in the region R2, when the spring is set to the softest state by maximizing the damping force of the shock absorber, excellent road grip can be ensured.

[0041] In addition, in region R3, similar to the above-mentioned region R1, the vibration intensity when the spring is set to the softest state is higher than the vibration intensity when the spring is set to the hardest state, and it can be determined that when the spring is set to the softest state, resonance occurs at a specific frequency. This resonance can be considered as a wheel resonance occurring in the high frequency domain. Therefore, in region R3, when the spring is set to the hardest state by minimizing the damping force of the shock absorber, excellent road grip can be ensured.

[0042] Furthermore, in region R4, it can be confirmed that almost similar vibration intensities are exhibited in all damping constants.

[0043] Referring to these results, in order to ensure excellent road grip, it is appropriate to determine the damping force of the shock absorber to set the spring in the hardest state in regions R1 and R3, and to set the spring in the softest state in the remaining regions R2 and R4.

[0044] Various embodiments of the present invention are characterized in that the road frequency (i.e., the frequency of the wheel vibration detected by the wheel vibration sensors 11a and 11b) is classified using the detection values ​​obtained by the wheel vibration sensors 11a and 11b, and the Figure 2 The damping forces of the shock absorbers 13a, 13b, 13c and 13d are then controlled in the region corresponding to the road frequency among the plurality of regions shown to ensure the best road grip.

[0045] Figure 3 is a block diagram of an apparatus for controlling damping force through road frequency classification according to various exemplary embodiments of the present invention.

[0046] Reference Figure 3 According to various exemplary embodiments of the present invention, the device for controlling the damping force by road frequency classification may include a high-pass filter component 21, a main frequency extraction module 22, a maximum amplitude and amplitude ratio extraction module 23, a road grip control determination module 24 and a shock absorber control module 25; the high-pass filter component 21 includes a plurality of high-pass filters, and the high-pass filters perform high-pass filtering on the detection values ​​of the wheel vibration input from the wheel vibration sensors 11a and 11b according to different cut-off frequencies; the main frequency extraction module 22 determines the main frequency of the wheel vibration according to the filter value output from the high-pass filter; the maximum amplitude and amplitude ratio extraction module 23 determines the maximum amplitude and amplitude ratio of the wheel vibration according to the filter value output from the high-pass filter; the road grip control determination module 24 determines whether to control the road grip according to the determined main frequency of the wheel vibration and the determined maximum amplitude and amplitude ratio of the wheel vibration; the shock absorber control module 25 determines the damping force of the shock absorber of the vehicle according to the determination result of the road grip control determination module 24 and the road surface roughness.

[0047] In an exemplary embodiment of the present invention, the cutoff frequency of the high-pass filter may be preset.

[0048] Figure 4 is a flowchart illustrating a method of controlling damping force through road frequency classification according to various exemplary embodiments of the present invention.

[0049] Reference Figure 4, the method for controlling the damping force by road frequency classification according to various exemplary embodiments of the present invention may include: detecting the vibration of the wheel by wheel vibration sensors 11a and 11b (S11), performing high-pass filtering on the detection values ​​of the wheel vibration input from the wheel vibration sensors 11a and 11b according to different cutoff frequencies (S12); determining the main frequency of the wheel vibration according to the filter value output from the high-pass filter (S13); determining the maximum amplitude of the wheel vibration according to the filter value output from the high-pass filter (S14); determining the amplitude ratio of the wheel vibration according to the filter value output from the high-pass filter (S15); determining whether to control the road grip according to the determined main frequency of the wheel vibration and the determined maximum amplitude and amplitude ratio of the wheel vibration (S16); determining the damping force of the shock absorber of the vehicle according to the determination result of whether to control the road grip and the road surface roughness (S17).

[0050] The detailed configuration and operation of the apparatus for controlling the damping force will be more clearly understood through the following description of a method of controlling the damping force through road frequency classification according to various exemplary embodiments of the present invention.

[0051] The method for controlling the damping force according to various exemplary embodiments of the present invention may start by detecting the vibration of the wheel through the wheel vibration sensors 11a and 11b (S11), and performing high-pass filtering on the detection values ​​of the wheel vibration input from the wheel vibration sensors 11a and 11b according to different cutoff frequencies (S12).

[0052] The performing of high pass filtering ( S12 ) may be performed by a high pass filter component 21 of the apparatus for controlling the damping force.

[0053] Figure 5 is a block diagram illustrating a detailed configuration of a high pass filter component of an apparatus for controlling a damping force according to various exemplary embodiments of the present invention.

[0054] like Figure 5 As shown, the high-pass filter assembly 21 of the apparatus for controlling damping force according to various exemplary embodiments of the present invention may include a plurality of high-pass filters 21 - 1 to 21 - n (n is a natural number of 2 or more).

[0055] The high-pass filters 21-1 to 21-n are provided to reduce the signal characteristics having a frequency lower than their respective cut-off frequencies, and the cut-off frequencies of the respective high-pass filters 21-1 to 21-n and the number of the high-pass filters 21-1 to 21-n may be appropriately determined according to the characteristics of the vehicle on which the wheel vibration sensors 11a and 11b are mounted. For example, the cut-off frequencies of the high-pass filters 21-1 to 21-n may be set close to the body resonance frequency or the wheel resonance frequency of the vehicle, and the number of the high-pass filters 21-1 to 21-n may be appropriately determined according to the required determination accuracy.

[0056] Thereafter, determining the main frequency of the wheel vibration (S13) may be performed. Determining the main frequency of the wheel vibration (S13) may be performed by the main frequency extraction module 22 of the apparatus for controlling the damping force.

[0057] Figure 6 is a block diagram illustrating a portion of a main frequency extraction module of an apparatus for controlling damping force according to various exemplary embodiments of the present invention in more detail.

[0058] Figure 6 The portion where the main frequency extraction module 22 receives and processes the first filtered value is shown. Figure 6 The above configuration of the main frequency extraction module 22 shown may be applied to each of the filtered values ​​output from the high-pass filters 21 - 1 to 21 - n.

[0059] Reference Figure 6 , the main frequency extraction unit 22-1 may include a zero crossing counter 221, an integrator 223 and a counting and output unit 224; the zero crossing counter 221 is configured to count the number of times the filter value output from the high-pass filter 21-1 crosses zero "0"; the integrator 223 is configured to accumulate the count value obtained by counting the number of times by the zero crossing counter 221 within a predetermined time period; the counting and output unit 224 is configured to update and output the count sum obtained by accumulating the count value within the predetermined time period in each predetermined time period. In addition, the main frequency extraction unit 22-1 may include a reset trigger 222, which is configured to provide the integrator 223 and the counting and output unit 224 with a predetermined time period (i.e., sampling time) for the integrator 223 to accumulate the count.

[0060] The reset trigger 222 may output a reset signal at each predetermined sampling time, and when the integrator 223 receives the reset signal, the integrator 223 may initialize the accumulated count value and then re-accumulate the count value. In addition, the counting and output unit 224 may output the accumulated count sum of the previous sampling time without receiving the reset signal from the reset trigger 222, and output the current accumulated count sum obtained by the integrator 223 when receiving the reset signal from the reset trigger 222.

[0061] from Figure 5 The filtered values ​​output by each high-pass filter 21-1 to 21-n shown in FIG. Figure 6 The portion of the main frequency extraction module 22 shown may accordingly generate a count value of a corresponding filtered value.

[0062] Determining the maximum amplitude of the wheel vibration (S14) and determining the amplitude ratio of the wheel vibration (S15) may be performed together with determining the main frequency of the wheel vibration (S13). Determining the maximum amplitude of the wheel vibration (S14) and determining the amplitude ratio of the wheel vibration (S15) may be performed by the maximum amplitude and amplitude ratio extraction module 23 of the device for controlling the damping force.

[0063] Figure 7 is a block diagram illustrating the remaining portion of a main frequency extraction module of the apparatus for controlling damping force according to various exemplary embodiments of the present invention in more detail.

[0064] Reference Figure 7 , through Figure 6 The configuration shown can generate the sum of the counts obtained from each filter value to identify the resonance area of ​​the vehicle body ( Figure 2 The counts and sums corresponding to the area R1 in the wheel resonance area ( Figure 2 Here, the division between the vehicle body resonance region and the wheel resonance region can be achieved by the cutoff frequency of the high-pass filters 21-1 to 21-n used to generate the respective filter values. For example, the vehicle body resonance region corresponding to the relatively low frequency (i.e., Figure 2 The count sum of the region R1 in the figure may be a count sum determined by a filter value generated by a high-pass filter whose cutoff frequency belongs to the vehicle body resonance region. In addition, the wheel resonance region corresponding to a relatively high frequency (i.e., Figure 2 The count sum of region R3) in the embodiment may be a count sum determined by a filter value generated by a high-pass filter having a cutoff frequency higher than an upper limit of the vehicle body resonance region.

[0065] The reason for this is that the count values ​​generated by the filtered values ​​of a high-pass filter having a low frequency as a cutoff frequency (i.e., the count values ​​in the vehicle body resonance area) may include all the count values ​​due to the vehicle body resonance and the wheel resonance, whereas the count values ​​generated by the filtered values ​​of a high-pass filter having a high frequency as a cutoff frequency (i.e., the count values ​​in the wheel resonance area) may include only the count values ​​due to the wheel resonance.

[0066] In the low frequency domain, vibration is generated due to the vehicle body resonance, whereby the count value may be low. Therefore, when it is determined that the main frequency is in the low frequency domain, the result obtained by subtracting the count sum in the wheel resonance region from the count sum in the vehicle body resonance region may be a negative value. On the other hand, when it is determined that the main frequency is in the high frequency domain where the vehicle body resonance is small and the wheel resonance is large, the result obtained by subtracting the count sum in the wheel resonance region from the count sum in the vehicle body resonance region may be a positive value. That is, the result obtained by subtracting the count sum in the wheel resonance region from the count sum in the vehicle body resonance region may be a trend for determining the main frequency rather than a value indicating the main frequency itself.

[0067] The frequency configured to separate the vehicle body resonance region and the wheel resonance region from each other may vary depending on the vehicle and may be determined in advance by an experimental method.

[0068] The vehicle body resonance region summing calculator 225 can sum the count sums corresponding to the vehicle body resonance region in the count sums obtained from each filter value, and the wheel resonance region summing calculator 226 can sum the count sums corresponding to the wheel resonance region in the count sums obtained from each filter value. Since the count sum is a value obtained by summing the number of times the filter value crosses zero "0" within a predetermined time, the frequency of the corresponding filter signal can be obtained by dividing the count sum by twice the predetermined sampling time. Therefore, since the frequency is reflected in the count sum, the range of the count sum corresponding to the vehicle body resonance region and the range of the count sum corresponding to the wheel resonance region can be predetermined, and accordingly, the vehicle body resonance region summing calculator 225 and the wheel resonance region summing calculator 226 can sum the count sums within the corresponding ranges.

[0069] The main frequency calculator 227 may determine the main frequency based on the difference between the sum of counts A corresponding to the vehicle body resonance region and the sum of counts B corresponding to the wheel resonance region. The main frequency calculator 227 may determine the main frequency by dividing the difference between the sum of counts A corresponding to the vehicle body resonance region and the sum of counts B corresponding to the wheel resonance region by twice the predetermined sampling time. The value of the main frequency determined and output by the main frequency calculator 227 is represented as an extracted main frequency value.

[0070] Figure 8 is a block diagram illustrating a portion of a maximum amplitude and amplitude ratio extraction module of an apparatus for controlling damping force according to various exemplary embodiments of the present invention in more detail.

[0071] Figure 8 The portion where the maximum amplitude and amplitude ratio extraction module 23 receives and processes the first filtered value is shown. Figure 8The above configuration of the maximum amplitude and amplitude ratio extraction module 23 shown may be applied to each of the filtered values ​​output from the high-pass filters 21 - 1 to 21 - n.

[0072] Reference Figure 8 , the maximum amplitude and amplitude ratio extraction unit 23-1 may include: an absolute value calculator 231, a maximum value calculator 233 and a maximum value determiner 234; the absolute value calculator 231 is configured to determine the absolute value of the filter value output from the high pass filter 21-1; the maximum value calculator 233 is configured to determine the maximum value of the absolute value determined by the absolute value calculator 231; the maximum value determiner 234 is configured to update and output the maximum value determined by the maximum value calculator 233 at each predetermined sampling time. In addition, the maximum amplitude and amplitude ratio extraction unit 23-1 may include a reset trigger 232 configured to provide a predetermined sampling time to the maximum value calculator 233 and the maximum value determiner 234.

[0073] The absolute value calculator 231 extracts an absolute value of the filter value, and the extracted absolute value may be a value corresponding to the magnitude of the filter value.

[0074] The maximum value calculator 233 is reset and the maximum value is determined again whenever a reset signal is input to the maximum value calculator 233, and the maximum value can be output as a larger value obtained by comparing the absolute value of the new input with the maximum absolute value determined in the previous sampling time before the latest reset signal is input.

[0075] When the reset signal is input to the maximum value determiner 234 , the maximum value determiner 234 may output the maximum value input from the maximum value calculator 233 until the next reset signal is input to the maximum value determiner 234 .

[0076] The reset trigger 232 may output a reset signal at each predetermined sampling time, the maximum value calculator 233 may output a larger value of the absolute value input in the current sampling time and the maximum absolute value determined in the previous sampling time, and when the maximum value calculator 233 receives the reset signal, the maximum value may be set to 0, and then the absolute value input in the current sampling time may be compared with the maximum absolute value determined in the previous sampling time. In addition, when no new reset signal is input to the maximum value determiner 234, the maximum value determiner 234 may output the maximum value determined due to the input of the previous reset signal, and when a new reset signal is input to the maximum value determiner 234, the maximum value determiner 234 may update the maximum value using the maximum value input from the maximum value calculator 233.

[0077] from Figure 5 The filtered values ​​output by each high-pass filter 21-1 to 21-n shown in FIG. Figure 8The portion of the maximum amplitude and amplitude ratio extraction module 23 shown, accordingly, can generate the maximum value of the amplitude of the corresponding filtered value.

[0078] Fig. 9 is a block diagram illustrating the rest of the maximum amplitude and amplitude ratio extraction module of the apparatus for controlling damping force according to various exemplary embodiments of the present invention in more detail.

[0079] Reference Fig. 9 , through Figure 8 The configuration shown can be used to select the maximum value of the amplitude obtained from each filter value and the resonance area of ​​the vehicle body ( Figure 2 The maximum values ​​corresponding to the region R1 in the wheel resonance region ( Figure 2 The vehicle body resonance region summing calculator 235 may sum the maximum values ​​corresponding to the vehicle body resonance region among the maximum values ​​obtained from the respective filtered values, and the wheel resonance region summing calculator 236 may sum the maximum values ​​corresponding to the wheel resonance region among the maximum values ​​obtained from the respective filtered values.

[0080] With and against Figure 7 In the same manner as described above with respect to the main frequency extraction module 22 shown, the body resonance region and the wheel resonance region can be determined based on the cutoff frequencies of the high-pass filters 21-1 to 21-n used to generate the respective filter values, and as described above, the frequency bands corresponding to the body resonance region and the wheel resonance region can be predetermined by experimental methods.

[0081] In addition, the maximum amplitude calculator 237 can output the extracted maximum amplitude value as the difference between the sum C of the maximum values ​​corresponding to the vehicle body resonance area and the sum D of the maximum values ​​corresponding to the wheel resonance area, and the amplitude ratio calculator 238 can output the extracted amplitude ratio value as the ratio of the sum C of the maximum values ​​corresponding to the vehicle body resonance area and the sum D of the maximum values ​​corresponding to the wheel resonance area.

[0082] After that, a determination may be made whether the road grip is to be controlled (S16). The determination may be performed by the road grip control determination module 24 of the device for controlling the damping force (S16).

[0083] Figure 3 The road grip control determination module 24 may determine whether to control the road grip based on the extracted main frequency value determined by the main frequency extraction module 22 and the extracted maximum amplitude value and the extracted amplitude ratio value determined by the maximum amplitude and amplitude ratio extraction module 23 .

[0084] For example, the road grip control determination module 24 may compare the extracted main frequency determined by the main frequency extraction module 22 with the first predetermined reference value Th1, compare the extracted maximum amplitude value determined by the maximum amplitude and amplitude ratio extraction module 23 with the second predetermined reference value Th2, and compare the extracted amplitude ratio value determined by the maximum amplitude and amplitude ratio extraction module 23 with the third predetermined reference value Th3. When the extracted main frequency is greater than the first predetermined reference value Th1, the extracted maximum amplitude value is less than the second predetermined reference value Th2, and the extracted amplitude ratio value is greater than the third predetermined reference value Th3, the road grip control determination module 24 may determine that the road grip is to be controlled. Here, the road grip is controlled to prevent the road grip from decreasing on a road with high road roughness such as an uneven road.

[0085] Here, the extracted main frequency value is configured as an index value for checking the road surface condition, but it is difficult to accurately check the road surface condition using only the extracted main frequency value. The extracted main frequency value may have a positive value due to high-frequency wheel vibration on an uneven road, but may also have a positive value if there is almost no low-frequency vehicle body vibration and thus wheel vibration occurs only on a flat road (e.g., an asphalt road).

[0086] In the current situation, in order to distinguish flat roads and uneven roads from each other, in addition to the extracted main frequency determined by the main frequency extraction module 22, the road grip control determination module 24 can also use the extracted maximum amplitude value and the extracted amplitude ratio determined by the maximum amplitude and amplitude ratio extraction module 23.

[0087] For example, on an uneven road, a high-amplitude vehicle body vibration is generated, so the extracted main frequency value can be a positive value, and the extracted maximum amplitude value and the extracted amplitude ratio can be large. On the other hand, on a flat road, the extracted main frequency value is a positive value, but a low-frequency vehicle body vibration is not generated, so the extracted maximum amplitude value and the extracted amplitude ratio can be small.

[0088] Accordingly, the extracted main frequency value, the extracted maximum amplitude value and the extracted amplitude ratio value are configured as indicators for checking the road condition, and whether to control the road grip can be determined by comparing these values ​​with the first predetermined reference value to the third predetermined reference value respectively.

[0089] Thereafter, determining the damping force of the shock absorber of the vehicle (S17) may be performed. Determining the damping force of the shock absorber of the vehicle (S17) may be performed by the shock absorber control module 25 of the device for controlling the damping force.

[0090] When the road grip control determination module 24 determines that the road grip is to be controlled (S16), the shock absorber control module 25 may control the shock absorber based on the road surface roughness. Figure 2 When the road grip control determination module 24 determines that the road grip is to be controlled (“Yes” in S16) and the road surface roughness is greater than the fourth predetermined reference value Th4 (“Yes” in S17), the shock absorber control module 25 can determine that the vehicle is in a state of Figure 2 The driving condition corresponding to the region R3 of FIG. 1 is determined, and the shock absorber coefficient is changed to achieve a hard state in which the shock absorbing force of the shock absorber is reduced ( S18 ).

[0091] Otherwise, when the road grip control determination module 24 determines that the road grip is not to be controlled ("No" in S16) and the road surface roughness is not greater than the fourth predetermined reference value Th4 ("No" in S19), the shock absorber control module 25 may determine that the vehicle is in a state of Figure 2 The driving condition corresponding to the region R1 of FIG. 1 is determined, and the shock absorber coefficient is changed to achieve a hard state in which the shock absorbing force of the shock absorber is reduced ( S18 ).

[0092] Alternatively, when the road grip control determination module 24 determines that the road grip is not to be controlled (“No” in S16) and the road surface roughness is greater than the fourth predetermined reference value Th4 (“Yes” in S19), the shock absorber control module 25 may determine that the vehicle is in a state of being ... Figure 2 The driving condition corresponding to the region R2 is determined, and the shock absorber coefficient is changed to achieve a soft state in which the shock absorbing force of the shock absorber is increased (S20).

[0093] For the current operation, the fourth reference value Th4 may correspond to a road surface roughness value that distinguishes the region R1 and the region R2 from each other.

[0094] The road surface roughness value applied to the present invention may be acquired through various sensors known in the art or through an algorithm for determining road surface roughness.

[0095] As described above, in the device and method for controlling the shock absorbing force by road frequency classification according to various embodiments of the present invention, it can be determined whether to perform control for ensuring road grip based on the results of the frequency and amplitude of the detection value of the wheel vibration obtained by analyzing the detection value from the wheel vibration sensor, and the shock absorbing force of the vehicle's shock absorber can be controlled based on the determination result.

[0096] Therefore, when road grip is required in an uneven road section, the apparatus and method for controlling damping force by road frequency classification according to an exemplary embodiment of the present invention can enable the vehicle to travel stably by adjusting the damping force of the shock absorber to ensure road grip.

[0097] It is obvious from the above description that in the device and method for controlling the shock absorbing force by road frequency classification according to various exemplary embodiments of the present invention, it can be determined whether to perform control for ensuring road grip based on the results of the frequency and amplitude of the detection value of the wheel vibration obtained by analyzing the detection value from the wheel vibration sensor, and the shock absorbing force of the vehicle's shock absorber can be controlled based on the determination result.

[0098] Therefore, when road grip is required in an uneven road section, the device and method for controlling the damping force by road frequency classification can enable the vehicle to travel stably by adjusting the damping force of the shock absorber to ensure the road grip.

[0099] For ease of interpretation and precise definition in the appended claims, the terms "upper", "lower", "inner", "outer", "upward", "downward", "upwardly", "downwardly", "front", "rear", "backside", "inner side", "outer side", "inwardly", "outwardly", "inner", "outer", "inner", "external", "forward", and "rearward" are used to describe features of the exemplary embodiments shown in the figures with reference to their positions. It will also be understood that the term "connect" or its derivatives refer to both direct and indirect connections.

[0100] The description presented above of the specific exemplary embodiments of the present invention is for the purpose of illustration and description. The foregoing description is not intended to be exhaustive or to limit the present invention to the precise form disclosed, and it is apparent that many modifications and variations can be made in accordance with the above teachings. The exemplary embodiments are selected and described in order to explain the specific principles of the present invention and its practical application, so that other technical personnel in the art can realize and utilize the various exemplary embodiments of the present invention and its different selected forms and modified forms. The scope of the present invention is intended to be limited by the appended claims and their equivalents.

Claims

1. A device for controlling the damping force by classifying the road frequency, the device include: a plurality of high-pass filters configured to perform high-pass filtering on the detection values ​​of the wheel vibration input from the wheel vibration sensor according to different cut-off frequencies; a main frequency extraction module configured to determine a main frequency of wheel vibration based on a plurality of filtered detection values ​​output from a plurality of high-pass filters; a maximum amplitude and amplitude ratio extraction module configured to determine a maximum amplitude and an amplitude ratio of wheel vibration based on filtered detection values ​​output from a plurality of high-pass filters; a road grip control determination module configured to determine whether to control the road grip according to the determined main frequency of the wheel vibration and the determined maximum amplitude and amplitude ratio of the wheel vibration; as well as The shock absorber control module is configured to determine a shock absorbing force of a shock absorber of the vehicle according to a determination result of the road grip control determination module and a road surface roughness.

2. The device for controlling the damping force by classifying the road frequency according to claim 1, in, The main frequency extraction module comprises: a plurality of zero-crossing counters, each zero-crossing counter being configured to count the number of times a filtered value output from a corresponding one of the plurality of high-pass filters crosses zero "0"; a plurality of integrators, each integrator being configured to accumulate and sum a count value obtained by counting by a corresponding one of the zero-crossing counters within a predetermined sampling time; a plurality of counting and output units, each of which is configured to update and output a count sum at each sampling time, the count sum being obtained by accumulating and summing the count values ​​by a corresponding one of the plurality of integrators; a body resonance region summing calculator configured to sum counts corresponding to a body resonance region of the vehicle among the count sums output from the plurality of counting and outputting units; a wheel resonance area summing calculator configured to sum counts corresponding to a wheel resonance area of ​​the vehicle among the count sums output from the plurality of counting and outputting units; and A main frequency calculator is configured to derive a main frequency of the wheel vibration based on a difference between a sum of counts corresponding to a body resonance region of the vehicle and a sum of counts corresponding to a wheel resonance region of the vehicle.

3. The device for controlling the damping force by classifying the road frequency according to claim 2, in, The main frequency calculator obtains the main frequency by dividing a difference between a sum of counts corresponding to the vehicle body resonance region and a sum of counts corresponding to the wheel resonance region by twice a predetermined sampling time.

4. The device for controlling the damping force by classifying the road frequency according to claim 1, in, The maximum amplitude and amplitude ratio extraction module comprises: a plurality of absolute value calculators, each absolute value calculator configured to determine an absolute value of a corresponding one of the filtered detection values; a plurality of maximum value calculators, each maximum value calculator configured to determine a maximum of the absolute values ​​determined by a corresponding one of the absolute value calculators; a plurality of maximum value determiners, each of the maximum value determiners being configured to update and output a maximum value determined by a corresponding one of the plurality of maximum value calculators at each predetermined sampling time; a body resonance region summing calculator configured to sum maximum values ​​corresponding to a body resonance region of the vehicle among the maximum values ​​output from the maximum value determiner; a wheel resonance area summing calculator configured to sum maximum values ​​corresponding to the wheel resonance area of ​​the vehicle among the maximum values ​​output from the maximum value determiner; a maximum amplitude calculator configured to determine a maximum amplitude of wheel vibration according to a difference between a sum of maximum values ​​corresponding to a body resonance region of the vehicle and a sum of maximum values ​​corresponding to a wheel resonance region of the vehicle; and An amplitude ratio calculator is configured to determine an amplitude ratio of wheel vibration according to a ratio of a sum of maximum values ​​corresponding to a body resonance region of the vehicle and a sum of maximum values ​​corresponding to a wheel resonance region of the vehicle.

5. The device for controlling the damping force by classifying the road frequency according to claim 1, in, When the main frequency of the wheel vibration determined by the main frequency extraction module is greater than a first predetermined reference value, the maximum amplitude of the wheel vibration determined by the maximum amplitude and amplitude ratio extraction module is less than a second predetermined reference value, and the amplitude ratio of the wheel vibration determined by the maximum amplitude and amplitude ratio extraction module is greater than a third predetermined reference value, the road grip control determination module determines that the road grip is to be controlled.

6. The device for controlling the damping force by classifying the road frequency according to claim 5, in, When the road grip control determination module determines that the road grip is to be controlled and the road surface roughness is greater than a fourth predetermined reference value, the damper control module changes the damping force of the damper to a first state in which the damping force is reduced.

7. The device for controlling the damping force by classifying the road frequency according to claim 5, in, When the road grip control determination module determines that the road grip is not to be controlled and the road surface roughness is not greater than a fourth predetermined reference value, the damper control module changes the damping force of the damper to a first state in which the damping force is reduced.

8. The device for controlling the damping force by classifying the road frequency according to claim 5, in, When the road grip control determination module determines that the road grip is not to be controlled and the road surface roughness is greater than a fourth predetermined reference value, the damping force of the damper control module changes the damping force of the damper to a second state in which the damping force is increased.

9. The device for controlling the damping force by classifying the road frequency according to claim 1, in, When the road grip control determination module determines that the road grip is to be controlled and the road surface roughness is greater than a predetermined reference value, the damper control module changes the damping force of the damper to a first state in which the damping force is reduced.

10. The device for controlling the damping force by classifying the road frequency according to claim 1, in, When the road grip control determination module determines that the road grip is not to be controlled and the road surface roughness is not greater than a predetermined reference value, the damper control module changes the damping force of the damper to a first state in which the damping force is reduced.

11. The device for controlling the damping force by classifying the road frequency according to claim 1, in, When the road grip control determination module determines that the road grip is not to be controlled and the road surface roughness is greater than a predetermined reference value, the damper control module changes the damping force of the damper to a second state in which the damping force is increased.

12. A method for controlling damping force by road frequency classification, the method include: High-pass filtering is performed on the detection value of the wheel vibration input from the wheel vibration sensor according to different cut-off frequencies; determining a main frequency of wheel vibration based on filtered detection values ​​output from a plurality of high-pass filters; determining a maximum amplitude and an amplitude ratio of wheel vibration based on filtered detection values ​​output from a plurality of high-pass filters; determining whether to control road grip based on the determined dominant frequency of the wheel vibration and the determined maximum amplitude and amplitude ratio of the wheel vibration; The damping force of the shock absorber of the vehicle is determined based on the result of the determination of whether the road grip is to be controlled and the road surface roughness.

13. The method according to claim 12, in, Determining the dominant frequencies of wheel vibration involves: Counting the number of times a filtered value output from a corresponding one of the plurality of high-pass filters crosses zero "0" by each of the plurality of zero-crossing counters; Accumulating and summing, by each of the plurality of integrators, a count value obtained by counting by a corresponding one of the zero-crossing counters within a predetermined sampling time; updating and outputting a count sum at each sampling time through each of the plurality of count sum output units, wherein the count sum is obtained by accumulating and summing the count values ​​through a corresponding one of the plurality of integrators; summing, by a body resonance region summing calculator, count sums corresponding to a body resonance region of the vehicle among the count sums output from the plurality of counting and output units; summing, by a wheel resonance area summing calculator, count sums corresponding to a wheel resonance area of ​​the vehicle among the count sums output from the plurality of counting and output units; The main frequency of the wheel vibration is obtained by the main frequency calculator based on the difference between the sum of the counts corresponding to the body resonance area of ​​the vehicle and the sum of the counts corresponding to the wheel resonance area of ​​the vehicle.

14. The method according to claim 13, in, The main frequency calculator obtains the main frequency by dividing a difference between a sum of counts corresponding to the vehicle body resonance region and a sum of counts corresponding to the wheel resonance region by twice a predetermined sampling time.

15. The method according to claim 12, in, Determining the maximum amplitude and amplitude ratio of wheel vibration based on the filtered detection values ​​output from the plurality of high pass filters includes: determining, by each of a plurality of absolute value calculators, an absolute value of a corresponding one of the filtered detection values; determining, by each of the plurality of maximum value calculators, a maximum value of the absolute values ​​determined by a corresponding one of the absolute value calculators; updating and outputting, by each of the plurality of maximum value determiners, a maximum value determined by a corresponding one of the maximum value calculators at each predetermined sampling time; summing, by a body resonance region summing calculator, maximum values ​​corresponding to a body resonance region of the vehicle among the maximum values ​​output from the maximum value determiner; summing, by a wheel resonance area summing calculator, maximum values ​​corresponding to a wheel resonance area of ​​the vehicle among the maximum values ​​output from the maximum value determiner; determining, by a maximum amplitude calculator, a maximum amplitude of the wheel vibration according to a difference between a sum of maximum values ​​corresponding to a body resonance region of the vehicle and a sum of maximum values ​​corresponding to a wheel resonance region of the vehicle; The amplitude ratio of the wheel vibration is determined by the amplitude ratio calculator according to the ratio of the sum of the maximum values ​​corresponding to the body resonance region of the vehicle to the sum of the maximum values ​​corresponding to the wheel resonance region of the vehicle.

16. The method according to claim 12, in, When determining whether to control road grip, when the main frequency of wheel vibration determined by the main frequency extraction module is greater than a first predetermined reference value, the maximum amplitude of wheel vibration determined by the maximum amplitude and amplitude ratio extraction module is less than a second predetermined reference value, and the amplitude ratio of wheel vibration determined by the maximum amplitude and amplitude ratio extraction module is greater than a third predetermined reference value, it is determined that the road grip is to be controlled.

17. The method according to claim 12, in, In determining the damping force of the shock absorber, when the road grip control determination module determines that the road grip is to be controlled and the road surface roughness is greater than a fourth predetermined reference value, the damping force of the shock absorber is changed to a first state in which the damping force is reduced.

18. The method according to claim 12, in, When determining the damping force of the shock absorber, when the road grip control determination module determines that the road grip is not to be controlled and the road surface roughness is not greater than a fourth predetermined reference value, the damping force of the shock absorber is changed to a first state in which the damping force is reduced.

19. The method according to claim 12, in, When determining the damping force of the shock absorber, when the road grip control determination module determines that the road grip is not to be controlled and the road surface roughness is greater than a fourth predetermined reference value, the damping force of the shock absorber is changed to a second state in which the damping force is increased.

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