JP2019051781A - Unsprung vibration detection device and suspension control device - Google Patents

Abstract

To provide an unsprung vibration detection device which can accurately detect vibration of an unsprung member, and to provide a suspension control device which achieves improvement of vibration inhibition effect of a vehicle body to improve riding quality.SOLUTION: An unsprung vibration detection device of the invention includes: a vibration information detection unit 1 which detects vibration information of an unsprung member W in a vehicle; a road surface displacement detection unit 2 which detects displacement between an unsprung member B and a road surface in the vehicle; and a vibration information calculation unit 3 which obtains vibration information of the unsprung member W on the basis of a high frequency component of the vibration information detected by the vibration information detection unit 1 and a low frequency component of the vibration information obtained by the road surface displacement detected by the road surface displacement detection unit 2. A suspension control device C includes the unsprung vibration detection device, a speed calculation unit 5, and a controller 4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an unsprung vibration detection device and a suspension control device.

  When the unsprung member climbs over the road surface unevenness while the vehicle is running, the suspension spring expands and contracts, and the support force by which the suspension spring supports the sprung member fluctuates, so the sprung member vibrates. In order to suppress the vibration of the sprung member, an actuator interposed between the unsprung member and the sprung member in the vehicle is interposed, and the thrust exerted by the actuator is controlled to There are suspension control devices that suppress vibrations.

  Such suspension control devices include not only a control for improving the damping performance of the sprung member in the vehicle, but also a control for suppressing the vibration of the unsprung member (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-49782

  In the conventional suspension control device, the vertical acceleration of the sprung member and the vertical acceleration of the unsprung member are detected, the sprung speed is obtained from the sprung acceleration, and the unsprung speed is obtained from the unsprung acceleration. Perform feedback control and unsprung feedback control.

  In addition, in the conventional suspension control device, a filter that performs integration is used to obtain the unsprung speed from the vertical acceleration of the unsprung member. However, due to the nature of the integration, the obtained unsprung speed has many low-frequency characteristics. The noise will be included.

  Therefore, since the detection accuracy of the unsprung speed in the sprung resonance frequency band is deteriorated, there is a possibility of adversely affecting the vibration control of the sprung member.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an unsprung vibration detection device that can accurately detect vibration of an unsprung member, and a suspension control device that can improve the vibration suppression effect of the vehicle body and improve riding comfort.

  In order to achieve the above object, an unsprung vibration detection device of the present invention includes a vibration information detection unit that detects vibration information of an unsprung member in a vehicle, and a road surface that detects displacement between the sprung member and the road surface in the vehicle. Based on the displacement detection unit, the high-frequency component of the vibration information detected by the vibration information detection unit, and the low-frequency component of vibration information obtained from the road surface displacement detected by the road surface displacement detection unit, vibration of the unsprung member A vibration information calculation unit for obtaining information. According to the unsprung vibration detector configured in this way, it is not necessary to perform an integration process that includes low-frequency noise, so vibration information that does not include noise can be detected.

  Further, the unsprung vibration detection device may obtain the vibration of the unsprung member by adding the low frequency component of the road surface displacement and the high frequency component of the vibration information of the unsprung member. The unsprung vibration detection device configured as described above can detect vibration information of the unsprung member with high accuracy in the entire frequency band.

  The unsprung vibration detection device may detect vibration information of the unsprung member using an acceleration sensor, or may detect using a stroke sensor interposed between the sprung member and the unsprung member. Alternatively, vibration information of the unsprung member may be detected by using a stroke sensor interposed between the sprung member and the unsprung member and an acceleration sensor for detecting the acceleration of the sprung member.

  Further, the unsprung vibration detection device extracts a low frequency component of vibration information obtained from road surface displacement by a low-pass filter having a cutoff frequency between the unsprung resonance frequency and the unsprung resonance frequency, You may extract the high frequency component of the vibration information detected by the vibration information detection part by the high-pass filter with the cut-off frequency between the sprung resonance frequencies. The use of a low-pass filter and a high-pass filter with the cut-off frequency set in this way is optimal for a suspension control device that suppresses vibration of the vehicle body.

  Further, the suspension control device uses an unsprung vibration detection device that obtains the displacement of the unsprung member as vibration information of the unsprung member, a speed calculation unit that obtains the speed of the unsprung member, and the displacement and speed of the unsprung member. And a controller for generating a control command to be given to an actuator interposed between the sprung member and the unsprung member. According to the suspension control device configured as described above, it is possible to detect all frequency bands including low frequency components and high frequency components of unsprung vibration information, and to control the influence of disturbance with high accuracy by cutting the influence of noise. Can seek power.

  According to the unsprung vibration detection device of the present invention, the vibration of the unsprung member can be accurately detected. Moreover, according to the suspension device of the present invention, the vibration suppression effect of the vehicle body is improved, and the riding comfort can be improved.

It is the figure which applied the unsprung vibration detection apparatus in one embodiment to the suspension control apparatus. It is a control block diagram of the unsprung vibration detection apparatus in one embodiment. It is a control block diagram of the unsprung vibration detection apparatus in the 1st modification of one embodiment. It is a control block diagram of the unsprung vibration detection apparatus in the 2nd modification of one embodiment. It is a control block diagram of the unsprung vibration detection apparatus in the 3rd modification of one embodiment.

  The present invention will be described below based on the embodiments shown in the drawings. As shown in FIGS. 1 and 2, the unsprung vibration detection device according to one embodiment is applied to a suspension control device C for damping a vehicle body B. The suspension control device C controls the actuator A interposed with the suspension spring S between the wheel W, which is an unsprung member of the vehicle V, and the vehicle body B, which is a sprung member, to suppress vibration of the vehicle body B.

  Hereinafter, each part will be described in detail. As shown in FIG. 1, a vehicle V as a system includes a wheel W having a tire Ti on its outer periphery, a vehicle body B, and a suspension spring S that is interposed between the wheel W and the vehicle body B and elastically supports the vehicle body B. It consists of and.

Vehicle V, the tire Ti and spring of spring constant K _t, the wheel W and the mass of the mass M _1, the suspension spring S and a spring of spring constant K _S, two mass two to the vehicle body B and the mass of the mass M ₂ This is a spring mass system having a degree of freedom, and can be expressed by a model of the spring mass system shown in FIG. Further, the vertical displacement of the road surface disturbance and X _0, the vertical displacement of the vehicle body B and X _1, the vertical displacement of the wheel W and X _2, are upward and positive in FIG.

In this example, the suspension control device C includes a vibration information detection unit 1, a road surface displacement detection unit 2, a vibration information calculation unit 3, and a controller 4 that obtains a control command _{fa_ref} to be given to the actuator A.

Suspension control device C, in this example, in order to detect the vertical displacement X ₂ of the wheel W as the vibration information of the wheel W is unsprung member, the vibration information detecting unit 1 and the road surface displacement detecting unit 2, the vibration And an information calculation unit 3. In this example, the vibration information detecting unit 1, in order to detect the vertical displacement X ₂ of the wheel W as the vibration information of the wheel W, provided with an acceleration sensor 11 and the integrator 12, the acceleration sensor 11 Then, the vertical acceleration d ² X ₂ / dt ² of the wheel W is detected and integrated twice to detect the vertical displacement X ₂ of the wheel W and input it to the vibration information calculation unit 3.

Road displacement detecting part 2 in order to detect the road surface displacement X ₀ is a vertical displacement of the road surface, and a road surface displacement detection sensor for detecting the distance between the road surface and the vehicle body B (relative displacement). The road surface displacement detection unit 2 detects the road surface displacement X ₀ based on the distance between the road surface and the vehicle body B and the vertical displacement of the vehicle body B, and inputs the detected road surface displacement X ₀ to the vibration information calculation unit 3.

As shown in FIG. 2, the vibration information calculation unit 3 includes a high-pass filter 31 that extracts a high-frequency component X _2H of the displacement X ₂ input from the vibration information detection unit 1, and the road surface displacement X detected by the road surface displacement detection unit 2. a low-pass filter 32 for extracting a low frequency component of _0, from the road surface displacement X ₀ treated with a low-pass filter 32 and the displacement acquiring unit 33 for obtaining the vertical displacement X ₂ of the wheel W, the wheel W of the high-pass filter 31 outputs and a low frequency component X _2L displacement X ₂ of the wheel W to the high frequency component X _2H displacement acquiring unit 33 of the displacement X ₂ is output by adding the adding unit 34 for obtaining the vertical displacement of the wheel W .

In this example, the high-pass filter 31 has an unsprung resonance frequency (near 10 Hz) whose cutoff frequency is the resonance frequency band of the wheel W and an unsprung resonance frequency (near 1-2 Hz) which is the resonance frequency band of the vehicle body B. The high frequency component X _2H including the resonance frequency band of the wheel W is extracted from the displacement X ₂ input from the vibration information detection unit 1. Therefore, the high-pass filter 31 in this example outputs the unsprung displacement in the unsprung member including the 10 Hz component, that is, the high frequency component X _2H of the vertical displacement X ₂ of the wheel W including the 10 Hz component. Thus obtaining a high frequency component X _2H of vertical displacement X ₂ of the wheel W in the high frequency component X _2H of vertical displacement X ₂ of the wheel W that does not contain low-frequency noise due to the integration process is obtained.

The high-pass filter 31 extracts the high-frequency component of the acceleration d ² X ₂ / dt ² before being integrated by the integrators 12 and 13, and then integrates by the integrators 12 and 13 to extract the high-frequency component X _{2H of the} displacement X _2. You may get Further, a high pass filter 31 may be inserted between the integrator 12 and the integrator 13.

In this example, the low-pass filter 32 has a cutoff frequency between an unsprung resonance frequency (near 10 Hz) that is the resonance frequency band of the wheel W and a sprung resonance frequency (near 1 Hz) that is the resonance frequency band of the vehicle body B. is set to a frequency, to extract the low frequency components including the resonance frequency band of the vehicle body B from the road surface displacement X ₀ input from the road surface displacement detecting portion 2.

The displacement acquisition unit 33 obtains the low frequency component X _2L of the displacement X ₂ of the wheel W using the transfer function G (x) from the low frequency component of the road surface displacement X _{0 to} the displacement of the wheel W as the unsprung member. . Displacement acquiring unit 33 receives the low-frequency component of a road surface displacement X ₀ to a low-pass filter 32 is output to the transfer function G (x), unsprung displacement at the spring lower member including a 1Hz component, i.e., it contains 1Hz component and outputs the low frequency component X _2L of vertical displacement X ₂ of the I wheel W. When the low frequency component X _2L of the vertical displacement X ₂ of the wheel W is obtained in this way, since the integration process is not performed, the low frequency component of the vertical displacement X ₂ of the wheel W that does not include low frequency noise. Is obtained. Incidentally, the low-pass filter 32 may be provided after the displacement acquiring unit 33, a low frequency component X _2L contained in the displacement X ₂ after obtaining a displacement X ₂ in advance displacement acquiring unit 33 in the low-pass filter 32 You may make it extract.

Addition unit 34, vertical displacement X ₂ of the high-frequency component X _2H and the low frequency component X _2L and adding to unsprung displacement of the unsprung portion of the wheel W, i.e., in the vertical direction of the wheel W displacement X ₂ Output. Vertical displacement X ₂ of the wheel W obtained in this way, since the unsprung displacement X ₂ of the unsprung member without the noise over the entire frequency band is obtained is determined accurately unsprung displacement X ₂ . Further, the wheel W is connected to the vehicle body B so as to be swingable in the vertical direction by the suspension arm, and the camber angle is also changed by the vertical movement of the wheel W. Therefore, the acceleration sensor 11 in the vibration information detection unit 1 Since drift that shifts the output center occurs, integrating the acceleration d ² X ₂ / dt ² makes it difficult to obtain an accurate displacement in a low frequency band, but such a problem can also be eliminated.

  In this example, the cut-off frequency of the high-pass filter 31 and the cut-off frequency of the low-pass filter 32 are set near the middle of the resonance frequency of the sprung member and the resonance frequency of the unsprung member (around 5 to 6 Hz). . Thus, when the cut-off frequencies of the high-pass filter 31 and the low-pass filter 32 are set, the resonance frequency band of the vehicle body B, which is a sprung member that is particularly important for vibration suppression control of the vehicle body B, and the wheel W, which is an unsprung member. The detection accuracy of vibration information in the resonance frequency band is more effectively improved. Therefore, if comprised in this way, the unsprung-vibration detection apparatus will become optimal when applied to the suspension control apparatus C which suppresses the vibration of the vehicle body B. However, the cut-off frequencies of the high-pass filter 31 and the low-pass filter 32 are not necessarily set as described above, and there is no problem in application to the suspension control device C. Further, the cutoff frequencies of the high pass filter 31 and the low pass filter 32 may be set to different values when it is desired to remove vibration information in a specific frequency band.

In addition, the suspension control device C in this example includes a speed calculation unit 5 in addition to the vibration information calculation unit 3. The speed calculator 5 differentiates the displacement X ₂ obtained by the vibration information calculator 3 to obtain a speed dX ₂ / dt. Since the speed calculation unit 5 calculates the speed dX ₂ / dt from the high-precision displacement X ₂ obtained by the vibration information calculation unit 3, the speed calculation unit 5 can obtain the high-precision speed dX ₂ / dt.

The controller 4 generates a control command f _{a_ref} based on the displacement X ₂ and the speed dX ₂ / dt as vibration information of the wheel W, which is an unsprung member, and obtains a control command to be input to the actuator A.

In this way, the controller 4 generates the control command f _{a_ref} to be given to the actuator A from the unsprung displacement X ₂ and the speed dX ₂ / dt obtained by adding the high frequency component X _2H and the low frequency component X _2L, and gives them to the actuator A. . The control command f _{a_ref} is a command for instructing the actuator A the direction of expansion and contraction and the magnitude of the thrust.

The actuator A is arranged in parallel with the suspension spring S and interposed between the vehicle body B and the wheel W. For example, the actuator A is a telescopic cylinder or an electric linear actuator using hydraulic pressure or pneumatic pressure. Have a source. The actuator A expands and contracts in _{response to} the input of the control command _{fa_ref} by exerting a thrust in the direction and magnitude as in the control command, and _vibrates the vehicle body B and the wheels W in the vertical direction.

Then, as shown in FIG. 1, a road surface displacement and X _0, the vertical displacement of the wheel W and X _2, the vertical displacement of the vehicle body B and X _1, the thrust is the output of the actuator A f _a Assuming that the upward direction is positive, the equation of motion of the vehicle body B can be expressed as the following equation (1) from the balance in the vertical direction of the vehicle body B that is a sprung member.

また、ばね下部材である車輪Ｗの上下方向の釣り合いから車輪Ｗの運動方程式は、以下の式（２）のように示せる。

Moreover, the equation of motion of the wheel W can be shown as the following formula (2) from the balance in the vertical direction of the wheel W that is the unsprung member.

さらに、アクチュエータＡを一次遅れ系とし、アクチュエータＡの制御指令ｆ_{ａ＿ｒｅｆ}から出力である推力ｆ_ａまでの応答遅れにおける時定数をＴとすると、アクチュエータＡの応答に関する微分方程式は、以下の式（３）のように示せる。

Additionally, the actuator A as a first-order lag system, when the time constant of the response delay from the control command f _{A_ref} actuator A to thrust f _a is the output is T, the differential equation for the response of the actuator A has the following formula (3 ).

式（１）を分解すると以下の式（４）となる。

When the equation (1) is decomposed, the following equation (4) is obtained.

ここで、路面変位Ｘ_０の変動（外乱）によって車輪Ｗが振動するが、車輪Ｗの振動によって車体Ｂへ伝達される伝達力を打ち消せば、車体Ｂへ車輪Ｗの振動の伝達をキャンセルして絶縁できる。つまり、路面変位Ｘ_０の変動（外乱）によって動かされる車体Ｂの変位Ｘ_１と、アクチュエータＡが推力ｆ_ａを発揮して動かされる車体Ｂの変位Ｘ_１が全く逆の大きさになれば両者が相殺される。車輪Ｗの変位Ｘ_２によって車体Ｂに作用する伝達力は、車輪Ｗの変位Ｘ_２によって懸架ばねＳが伸縮して懸架ばねＳが発揮するばね力となるから、アクチュエータＡの推力ｆ_ａが車輪Ｗの変位によって懸架ばねＳが発揮するばね力Ｋ_ＳＸ_２の符号を反転した値に等しくなればよい。

Here, the variation of the road surface displacement X ₀ (disturbance) by the wheel W is vibrated, if Uchikese transmission force transmitted to the vehicle body B by the vibration of the wheel W, cancels the transmission of vibrations of the wheel W to the vehicle body B Can be insulated. Both words, the displacement X ₁ of the vehicle body B which is moved by the fluctuation of the road surface displacement X ₀ (the disturbance), if the magnitude of the displacement X ₁ is completely reverse the vehicle body B which the actuator A is moved by exerting a thrust f _a Is offset. Transmitting force acting on the vehicle body B by a displacement X ₂ of the wheel W, since the suspension spring S and the suspension spring S is stretching the displacement X ₂ of the wheel W is a spring force that exerts thrust f _a of the actuator A the wheel suspension spring S by the displacement of W may if equal to the value obtained by inverting the sign of the spring force K _S X ₂ to exert.

In formula (1), if K S and _(X 2 _{-X 1)} and a value related numeric opposite sign equal thrust f _a, as indicated that the acceleration does not occur in the vehicle body B I think. In other words, it seems like may be used as the thrust _{f a = -K S (X 2} -X 1). However, (X ₂ −X ₁ ) is a relative displacement between the vehicle body B and the wheel W, and the change in the relative displacement is caused by a change in the posture of the vehicle body B due to turning, braking or acceleration, and a change in the load on the vehicle body B. Whether it is caused by road surface displacement cannot be determined. For example, when reducing the suspension spring S sinks forward of the vehicle body B by pitching _and exert a thrust to f _a = -K actuator A as _{S (X} 2 -X _1), to facilitate the sinking of the vehicle body B Will exert thrust in the direction. When the vehicle body B is lifted, the lift is promoted. As described above, in the control that feeds back the relative displacement between the vehicle body B and the wheel W, there is a mode in which the posture of the vehicle body B is not stable and the vibration of the vehicle body B oscillates. Accordingly, the spring force K _S · X ₂ thrust f _a of the actuator A is the suspension spring S is exerted by the displacement X ₂ of the wheel W as transmission force, so as to cancel the transmission power, and obtains a thrust f _a of the actuator A That's fine. Considering the above, the following equation (5) may be established.

他方、ラプラス演算子をｓとして、式（３）の制御指令とアクチュエータＡの推力の関係を伝達関数で表現すると、伝達関数は、以下の式（６）で表現される。

On the other hand, when the Laplace operator is s and the relationship between the control command of Expression (3) and the thrust of the actuator A is expressed by a transfer function, the transfer function is expressed by the following Expression (6).

この式（６）を式（５）に代入すると、式（７）となる。なお、式（７）中で、ｋはゲインである。この式（７）は、アクチュエータＡの制御指令ｆ_{ａ＿ｒｅｆ}の入力から推力ｆ_ａを出力するまでの応答遅れが勘案された式となる。

When this equation (6) is substituted into equation (5), equation (7) is obtained. In Expression (7), k is a gain. The equation (7) consists of an input control command f _{A_ref} actuator A and expression response delay has been consideration of to the output of thrust f _a.

ラプラス演算子ｓが乗算される変数は微分されるので、式（７）を展開して整理すると、以下の式（８）が得られる。

Since the variable multiplied by the Laplace operator s is differentiated, the following formula (8) is obtained by expanding and organizing the formula (7).

式（８）から理解できるように、変位Ｘ_２に対して位相が進む速度を利用してアクチュエータＡの応答遅れを補償できる制御指令ｆ_{ａ＿ｒｅｆ}を求める。この式（８）において、アクチュエータＡの制御指令ｆ_{ａ＿ｒｅｆ}の入力から推力ｆ_ａを出力するまでの応答遅れについて、予め、実機において時定数Ｔとゲインｋに計測すれば足り、車輪Ｗの変位Ｘ_２は前述のばね下振動検知装置で検知される。よって、制御器４は、式（８）を演算すれば制御指令ｆ_{ａ＿ｒｅｆ}を求め得る。このように制御指令ｆ_{ａ＿ｒｅｆ}を求めてアクチュエータＡへ入力するとアクチュエータＡは、推力ｆ_ａを発揮して車輪Ｗからの伝達力を打ち消せるので、路面からの外乱入力による車体Ｂの振動を相殺して、車体Ｂの振動を抑制できる。

As can be understood from the equation (8), by utilizing the speed at which the phase is advanced relative to the displacement X ₂ obtains a control command f _{A_ref} capable of compensating the response delay of the actuator A. In the formula (8), the response delay from the input of the control instruction f _{A_ref} actuator A to the output of thrust f _a, in advance, sufficient by measuring the constant T and the gain k when the actual displacement of the wheel W X ₂ is detected by the aforementioned unsprung vibration detector. Therefore, the controller 4 can obtain the control command _{fa_ref} by calculating Expression (8). Thus seeking control command f _{A_ref} inputs to the actuator A the actuator A, since Uchikeseru the transmission force from the wheels W to exert thrust f _a, to cancel the vibration of the vehicle body B due to a disturbance inputs from the road surface Thus, vibration of the vehicle body B can be suppressed.

As described above, according to the suspension control apparatus of the present embodiment (the unsprung vibration sensing device) C, is obtained displacement X ₂ under spring cut the influence of noise. Thus, while compensating for the response delay of the actuator A by simple arithmetic processing so Uchikeseru the influence of disturbance, can offset the vibration of the vehicle body B due to changes in the road surface displacement X ₀ is a disturbance input to a precision, vibration of the vehicle body B The suppression effect can be improved.

Although the unsprung vibration information can be detected using only the unsprung acceleration d ² X ₂ / dt ² detected by the acceleration sensor 11, in practice, the unsprung acceleration is integrated to obtain the vibration information. For this reason, low frequency noise increases due to the nature of integration, and it is difficult to accurately detect low frequency unsprung displacement and unsprung acceleration. Further, since sensor noise is generated, vibration information in a low frequency band is detected through a low-pass filter for noise reduction, and detection accuracy is poor. On the other hand, according to the suspension control apparatus C of the present embodiment, the entire frequency band including the low frequency component X _2L and the high frequency component X _2H of the unsprung vibration information can be detected, and the influence of noise is cut. Since the control force that cancels out the influence of the disturbance with high accuracy is obtained, the vibration suppression effect of the vehicle body B is improved and the riding comfort is improved.

In the case where the actuator A is provided with a characteristic of the secondary delay, the natural angular frequency and omega, when the attenuation factor zeta, when the gain and k, the transfer function from the control command f _{A_ref} to thrust f _a Is expressed by the following equation (9).

この式（９）を式（５）に代入すると、式（１０）となる。式（１０）は、アクチュエータＡの制御指令ｆ_{ａ＿ｒｅｆ}の入力から推力ｆ_ａを出力するまでの二次の応答遅れが勘案された式となる。

When this equation (9) is substituted into equation (5), equation (10) is obtained. Equation (10) is a second-order response delay from the input of the control instruction f _{A_ref} actuator A to the output of thrust f _a is consideration equation.

ラプラス演算子ｓが乗算される変数は微分され、ラプラス演算子ｓの二乗が乗算される変数は二回微分となるので、式（１０）を展開して整理すると、以下の式（１１）が得られる。

The variable multiplied by the Laplace operator s is differentiated, and the variable multiplied by the square of the Laplace operator s is differentiated twice. Therefore, when formula (10) is expanded and arranged, the following formula (11) is obtained. can get.

式（１１）から理解できるように、アクチュエータＡが二次の応答遅れ位の特性を備えている場合、一次遅れのアクチュエータＡに比較して、変位Ｘ_２から位相が進んだ速度ｄＸ_２／ｄｔに加えて、更に位相が進んだ加速度ｄ^２Ｘ_２／ｄｔ^２を加味して、制御指令ｆ_{ａ＿ｒｅｆ}を求めればよい。つまり、二次遅れのアクチュエータＡの場合、制御指令ｆ_{ａ＿ｒｅｆ}を求めるために利用するばね下部材である車輪Ｗの振動情報は、変位Ｘ_２、速度ｄＸ_２／ｄｔおよび加速度ｄ^２Ｘ_２／ｄｔ^２となる。このようにすれば、アクチュエータＡの応答遅れを補償しつつ、路面からの外乱入力による車体Ｂの振動を相殺して、車体Ｂの振動を抑制できる。よって、アクチュエータＡが高次の応答遅れとなれば、車輪Ｗの変位Ｘ_２から位相が次数分進んだ情報を加味すれば、アクチュエータＡの応答遅れの特性に対応して車体Ｂの振動を抑制できる。よって、制御指令ｆ_{ａ＿ｒｅｆ}を得るためのばね下部材である車輪Ｗの振動情報は、アクチュエータＡの応答遅れの次数に応じて、前述のように決定すればよい。

As can be understood from the equation (11), when the actuator A has a second-order response delay characteristic, the velocity dX ₂ / dt in which the phase has advanced from the displacement X ₂ compared to the first-order delay actuator A. In addition to the above, the control command _{fa_ref} may be obtained by taking into account the acceleration d ² X ₂ / dt ^{2 in} which the phase has further advanced. That is, in the case of the second-order lag actuator A, the vibration information of the wheel W, which is an unsprung member used to obtain the control command f _{a_ref} , is displacement X ₂ , velocity dX ₂ / dt, and acceleration d ² X ₂ / dt. ² . In this way, the vibration of the vehicle body B can be suppressed by compensating for the response delay of the actuator A and canceling the vibration of the vehicle body B due to disturbance input from the road surface. Therefore, if the actuator A is a higher order response delay, if considering the information phase advances a few minutes following the displacement X ₂ of the wheel W, suppressing the vibration of the vehicle body B so as to correspond to the characteristics of the response delay of the actuator A it can. Therefore, the vibration information of the wheel W that is an unsprung member for obtaining the control command _{fa_ref} may be determined as described above according to the order of the response delay of the actuator A.

In addition, as shown in FIG. 3, the road surface displacement detection unit 2 includes a camera 21 that is installed on the vehicle body B and images the road surface, instead of the road surface displacement detection sensor for detecting the road surface displacement. may be configured with a road surface displacement calculation unit 22 that the captured road image data image processing to determine the road surface displacement X _0.

Even in the configuration shown in FIG. 3, the road surface displacement detection unit 2 directly detects the road surface displacement and does not perform integration processing, so the low frequency component X _2L of the displacement X ₂ of the wheel W that is an unsprung member that does not include noise or the like. Is obtained. Thus, over the entire frequency band displacement X ₂ of good wheels W accuracy obtained, since obtaining a control force to cut the influence of noise cancel the influence of the disturbance with high accuracy, improving the vibration suppressing effect of the vehicle body B And ride comfort improves.

As shown in FIG. 4, the vibration information detection unit 1 includes a stroke sensor 15 interposed between the wheel W and the vehicle body B together with the suspension spring S and the actuator A instead of the acceleration sensor 11. May be. Stroke sensor 15 detects the relative displacement X _2-1 wheel W and the vehicle body B, and which detects the relative displacement X _2-1 away from each other as a positive value. By filtering this relative displacement _{X 2-1} in the high-pass filter 17 may determine the displacement _{X 2} of the wheel W. The relative displacement X _2-1 for detecting a stroke sensor 15, includes a vibration component of the unsprung resonance frequency of the wheel W, if filtered by a high pass filter 17 may extract a displacement X ₂ of the wheel W. Incidentally, the relative displacement X _2-1 for detecting a stroke sensor 15 includes a vibration component of the sprung resonance frequency of the vehicle body B. Therefore, by setting the cutoff frequency of the high-pass filter 17 to a frequency between the unsprung resonance frequency and the sprung resonance frequency, it can be extracted displacement X ₂ of the wheel W from the relative displacement X _2-1.

Further, as shown in FIG. 5, the vibration information detection unit 1 is arranged between the acceleration sensor 14 that detects the vertical acceleration of the vehicle body B on the vehicle body B and the wheel W and the vehicle body B instead of the acceleration sensor 11. A stroke sensor 15 interposed with the suspension spring S and the actuator A and a displacement calculation unit 16 may be provided. Stroke sensor 15 detects the relative displacement X _2-1 wheel W and the vehicle body B, and which detects the relative displacement X _2-1 away from each other as a positive value. Then, the displacement calculation unit 16 calculates the vertical acceleration d ² X ₁ / dt ² of the vehicle body B detected by the acceleration sensor 14 twice from the displacement X ₁ obtained by integrating twice by the integrators 12 and 13. it may be obtained a displacement X ₂ of the wheel W in by subtracting the relative displacement X _2-1 between the wheel W and the vehicle body B to be detected.

Vibration information calculation section 3 was obtained by subtracting the relative displacement _{X 2-1} detected by the stroke sensor 15 from the displacement _{X 1} of obtaining the vertical acceleration ^d 2 _X 1 / dt ² of the vehicle body B by integrating twice a displacement _{X 2} is treated with a high-pass filter 31, seeking a high frequency component _{X 2H} displacement _{X 2,} may be obtained a displacement _{X 2} is added to the low frequency component _{X 2L} displacement _{X 2.} In this way, even with the configuration shown in FIG. 4, it is possible to detect the entire frequency band including the low frequency component and the high frequency component X _2H of the unsprung vibration information, and control to cancel the influence of disturbance with high accuracy by cutting the influence of noise. Since the force is obtained, the vibration suppressing effect of the vehicle body B is improved and the riding comfort is improved.

  In addition, as described above, the road surface displacement detection unit 2 uses a road surface displacement detection sensor, but it is only necessary to detect vibration of only a low frequency, so a high performance road surface displacement detection sensor with a fast sampling cycle must be used. good.

Further, in the place where the aforementioned, the vibration information of the unsprung member although the displacement X ₂ of the wheel W, may be acceleration or velocity of the vibration information wheel W. For example, when the vibration information is acceleration or speed, the vibration information detection unit 1 detects the acceleration of the unsprung member, and obtains the speed by integrating the acceleration or the acceleration. A high frequency component of acceleration or velocity is obtained. Further, the acceleration or the speed is obtained using a transfer function from the road surface displacement X ₀ detected by the road surface displacement detection unit 2 to the acceleration or speed of the unsprung member. Then, the vibration information calculation unit 3 extracts the high frequency component of acceleration or speed obtained by the vibration information detection unit 1, extracts the low frequency component of acceleration or velocity obtained by the road surface displacement detection unit 2, and extracts vibration information from them. If the acceleration or acceleration is obtained, a highly accurate acceleration or velocity that does not include noise and drift in the entire frequency band can be obtained.

  In the above description, the present invention has been described by taking the case where the unsprung vibration detection device is the suspension device C as an example. However, the unsprung vibration detection device can be used other than the suspension device C of the vehicle V.

  The preferred embodiments of the present invention have been described in detail above, but modifications, changes, and modifications can be made without departing from the scope of the claims.

DESCRIPTION OF SYMBOLS 1 ... Vibration information detection part, 2 ... Road surface displacement detection part, 3 ... Vibration information calculating part, 11, 14 ... Acceleration sensor, 15 ... Stroke sensor, 31 ... Low pass filter, 32: high-pass filter, B: vehicle body (sprung member), V ... vehicle, W ... wheel (unsprung member)

Claims (7)

A vibration information detector for detecting vibration information of an unsprung member in the vehicle;
A road surface displacement detector for detecting displacement between the sprung member and the road surface in the vehicle;
Based on the high frequency component of the vibration information detected by the vibration information detection unit and the low frequency component of the vibration information obtained from the road surface displacement detected by the road surface displacement detection unit, vibration information of the unsprung member Vibration information calculation unit for obtaining
An unsprung vibration detection device comprising: The unsprung vibration detection device according to claim 1, wherein the vibration information calculation unit obtains the vibration of the unsprung member by adding a low frequency component of the vibration information and a high frequency component of the vibration information. . The unsprung vibration detection device according to claim 1, wherein the vibration information detection unit includes an acceleration sensor that detects an acceleration in a vertical direction of the unsprung member. The unsprung vibration detection device according to claim 1, wherein the vibration information detection unit includes a stroke sensor interposed between the sprung member and the unsprung member. The unsprung vibration detection device according to claim 4, wherein the vibration information detection unit further includes an acceleration sensor that detects an acceleration of the sprung member. The vibration information calculation unit includes a low-pass filter that extracts a low-frequency component of the vibration information obtained from the road surface displacement, and a high-pass filter that extracts a high-frequency component of the vibration information detected by the vibration information detection unit. ,
The cut-off frequency of the low-pass filter and the high-pass filter is set to a frequency between the unsprung resonance frequency of the unsprung member and the unsprung resonance frequency of the sprung member. The unsprung vibration detection device according to any one of the above. The unsprung vibration detection device according to any one of claims 1 to 5, wherein a displacement of the unsprung member is obtained as vibration information of the unsprung member.
A speed calculator for determining the speed of the unsprung member;
Suspension control, comprising: a controller that generates a control command to be given to an actuator interposed between the sprung member and the unsprung member using the displacement and speed of the unsprung member. apparatus.

Images