JP2014028558A - Suspension control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce inflow of an air current to a lower surface of a vehicle body at high-speed travelling, and to reduce floating and pitching of the vehicle body.SOLUTION: Using an upper spring acceleration sensor 8 and integrator 12, an upper spring speed V1 is detected. Using the upper spring acceleration sensor 8, a lower spring acceleration sensor 9, a subtractor 14 and the integrator 13, a relative speed V2 between a vehicle body 1 and a wheel 2 is detected. A gain multiplication processing part 15 sets extension-side front wheel target damping force DFf to be high and contraction-side front wheel target damping force DFf to be low, when the vehicle speed is high, compared to a case when the vehicle speed is low, and sets extension-side rear wheel target damping force DFr to be low and contraction-side rear wheel target damping force DFr to be high. A damping force map 20 calculates a command current value I on the basis of the target damping force DFf and DFr and the relative speed V2. This configuration enables a vehicle to behave nose-down at high speed.

Description

  The present invention relates to a suspension control device that is mounted on a vehicle such as a four-wheeled vehicle and is preferably used for buffering vibration of the vehicle.

  In general, a vehicle such as an automobile is provided with a damping force adjustment type shock absorber between a vehicle body and each axle, and a suspension control device configured to adjust a damping force characteristic by the shock absorber using an adjustment signal is mounted. (For example, see Patent Documents 1 to 3). In this type of suspension control device according to the prior art, for example, vibrations in the upward and downward directions of the vehicle body are detected as sprung speed or sprung acceleration, and a shock absorber is generated so as to generate a damping force corresponding to the detected speed. In contrast, an adjustment signal was output. Further, in the suspension control device according to the prior art, the gain is changed or the damping force is adjusted according to the vehicle speed for the purpose of reducing the flickering of the vehicle body and the fluttering under the spring.

JP-A-8-216645 JP-A-6-270632 JP-A-7-323714

  By the way, in the suspension control apparatus according to the prior art, the gain of the damping force is set according to the traveling state of the vehicle such as the vehicle speed and the influence of the road surface for the purpose of reducing the vehicle behavior. For this reason, when the vehicle body shakes at a high vehicle speed, the damping force of the shock absorber is controlled so as to reduce pitching, that is, to make the vehicle body posture parallel to the road surface. As a result, when the vehicle body rises, there is a concern that airflow flows into the lower surface of the vehicle body, the vehicle body is lifted, and pitching is increased.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to reduce the inflow of airflow to the lower surface of the vehicle body at a high vehicle speed, and to reduce the lifting and pitching of the vehicle body. Is to provide.

  In order to solve the above-described problem, the invention according to claim 1 includes a damping force adjustment type shock absorber that is interposed between a vehicle body and a wheel of a vehicle and that adjusts damping force characteristics using an adjustment signal. In the suspension control apparatus, a vehicle body side vertical speed detection unit that detects the vehicle body vertical speed as the vehicle body vertical speed, and the damping force adjustment formula based on the vehicle body vertical speed by the vehicle body vertical speed detection unit A damping force calculation unit that calculates a target damping force generated in the shock absorber, a relative speed detection unit that detects a relative speed between the vehicle body and the wheel in the upward and downward directions, and a target damping force by the damping force calculation unit And an adjustment signal output unit that outputs an adjustment signal for adjusting the damping force characteristic of the damping force adjustment type shock absorber based on the relative speed by the relative speed detection unit, and a vehicle speed detection unit that detects the traveling speed of the vehicle as a vehicle speed And with The damping force calculation unit sets the target damping force on the expansion side of the front wheels to be lower and the target damping force on the contraction side to be lower when the vehicle speed by the vehicle speed detection unit is high than when the vehicle speed is low, and / or It is characterized in that the target damping force on the expansion side of the wheel is set low and the target damping force on the contraction side is set high.

  According to the present invention, it is possible to reduce the inflow of airflow to the lower surface of the vehicle body at high vehicle speeds, and to reduce the lifting and pitching of the vehicle body.

It is a figure showing typically a suspension control device by an embodiment of the invention. It is a block diagram which shows the controller in FIG. It is a block diagram which shows the gain multiplication process part in FIG. It is explanatory drawing which shows the gain map for front wheels in FIG. FIG. 4 is an explanatory diagram showing a rear wheel gain map in FIG. 3. It is explanatory drawing which shows the front-wheel target damping force calculator in FIG. It is explanatory drawing which shows the rear-wheel target damping force calculator in FIG. It is explanatory drawing which shows the damping force map in FIG. It is explanatory drawing which shows the vehicle behavior at the time of the high vehicle speed and the low vehicle speed. It is a flowchart which shows the control content by the controller in FIG.

  Hereinafter, a suspension device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case where the suspension device is applied to a four-wheeled vehicle.

  Here, FIG. 1 to FIG. 10 show an embodiment of the present invention. The vehicle body 1 constitutes a vehicle body. Below the vehicle body 1, for example, left and right front wheels and left and right rear wheels (hereinafter collectively referred to as wheels 2) are provided. The wheels 2 include tires 3. At this time, the tire 3 acts as a spring that absorbs fine irregularities on the road surface.

  The suspension device 4 is provided between the vehicle body 1 and the wheel 2. The suspension device 4 includes a suspension spring 5 (hereinafter referred to as a spring 5) and a damping force adjustment type shock absorber (hereinafter referred to as a shock absorber 6) provided between the vehicle body 1 and the wheel 2 in parallel with the spring 5. ). FIG. 1 illustrates a case where a set of suspension devices 4 is provided between the vehicle body 1 and the wheels 2. However, for example, a total of four suspension devices 4 are individually provided between the four wheels 2 and the vehicle body 1, and only one of these is schematically illustrated in FIG. 1. .

  Here, the shock absorber 6 of the suspension device 4 is configured using a damping force adjusting hydraulic shock absorber. The shock absorber 6 includes a damping force adjusting valve or the like for continuously adjusting the generated damping force characteristic (damping force characteristic) from a hard characteristic (hard characteristic) to a soft characteristic (soft characteristic). An actuator 7 is attached. Note that the damping force adjusting valve may be capable of adjusting the damping force characteristics in two or more stages without being continuous.

  The sprung acceleration sensor 8 is provided on the vehicle body 1. Specifically, the sprung acceleration sensor 8 is attached to the vehicle body 1 at a position near the shock absorber 6, for example. The sprung acceleration sensor 8 detects the vibration acceleration in the upward and downward directions on the side of the vehicle body 1 that is a so-called spring upper side, and outputs a detection signal to the controller 11 described later.

  The unsprung acceleration sensor 9 is provided on the vehicle wheel 2 side. The unsprung acceleration sensor 9 detects vibration acceleration in the upward and downward directions on the side of the wheel 2 that is a so-called unsprung side, and outputs a detection signal to the controller 11 described later.

  The vehicle speed sensor 10 is provided, for example, on the vehicle wheel 2 side, and constitutes a vehicle speed detection unit that detects the traveling speed of the vehicle as the vehicle speed V3. The vehicle speed sensor 10 detects, for example, the number of rotations of the wheel 2 that changes according to the traveling speed of the vehicle, and outputs a detection signal to the controller 11 described later. Thus, the controller 11 can obtain the vehicle speed V3 based on the detection signal from the vehicle speed sensor 10.

  The controller 11 is composed of, for example, a microcomputer and constitutes control means for controlling the shock absorber 6 based on detection signals from the acceleration sensors 8 and 9 and the vehicle speed sensor 10. The input side of the controller 11 is connected to the acceleration sensors 8 and 9, the vehicle speed sensor 10 and the like, and the output side is connected to the actuator 7 and the like of the shock absorber 6. The controller 11 has a storage unit 11A composed of a ROM, a RAM, and the like.

  The storage unit 11A of the controller 11 includes a vehicle speed sensitive gain multiplication processing unit 15 that outputs target damping forces DFf and DFr based on the vehicle speed V3 and the sprung speed V1 shown in FIG. 3, and a target damping shown in FIG. A damping force map 20 indicating the relationship between the forces DFf and DFr, the relative speed V2 and the command current value I is stored.

  Here, as shown in FIG. 2, the controller 11 includes integrators 12 and 13, a subtracter 14, a gain multiplication processing unit 15, and a damping force map 20. Then, the integrator 12 of the controller 11 calculates a sprung speed V1 that is a speed in the upward and downward directions of the vehicle body 1 by integrating the detection signal from the sprung acceleration sensor 8. Therefore, the sprung acceleration sensor 8 and the integrator 12 constitute a vehicle body side vertical speed detection unit, and the integrator 12 outputs a sprung speed V1 that is the vehicle body side vertical speed.

  On the other hand, the subtracter 14 subtracts the detection signal from the unsprung acceleration sensor 9 from the detection signal from the sprung acceleration sensor 8, and calculates the difference between the sprung acceleration and the unsprung acceleration. At this time, this difference value corresponds to the relative acceleration between the vehicle body 1 and the wheel 2. Then, the integrator 13 integrates the relative acceleration output from the subtractor 14 and calculates an upward and downward relative speed V2 between the vehicle body 1 and the wheel 2. For this reason, the sprung acceleration sensor 8, the unsprung acceleration sensor 9, the subtractor 14 and the integrator 13 constitute a relative speed detector, and the integrator 13 outputs a relative speed V2.

  The gain multiplication processing unit 15 constitutes a damping force calculation unit, and outputs target damping forces DFf and DFr to be generated in the shock absorber 6 based on the vehicle speed V3 and the sprung speed V1. The target damping forces DFf and DFr are obtained from, for example, skyhook control theory. As shown in FIG. 3, the gain multiplication processing unit 15 includes a gain setting unit 15A and a front wheel / rear wheel target damping force calculator 15B.

  The gain setting unit 15A includes a front wheel gain map 16 and a rear wheel gain map 17 which will be described later. The gain setting unit 15A sets a front wheel gain Gf and a rear wheel gain Gr based on the vehicle speed V3 of the vehicle speed sensor 10.

  The front wheel / rear wheel target damping force calculator 15B includes a front wheel target damping force calculator 18 and a rear wheel target damping force calculator 19 which will be described later. The front wheel / rear wheel target damping force calculator 15B multiplies the front wheel gain Gf by the gain setting unit 15A by the sprung speed V1 on the front wheel side to calculate the front wheel target damping force DFf, and the rear by the gain setting unit 15A. The rear wheel target damping force DFr is calculated by multiplying the wheel gain Gr and the rear wheel sprung speed V1.

  The front wheel gain map 16 sets the front wheel gain Gf based on the signal directions of the vehicle speed V3 and the sprung speed V1 on the front wheel side. Specifically, the front wheel gain map 16 indicates that when the vehicle speed V3 is lower than a predetermined threshold value Vt of, for example, about 100 km / h (at low vehicle speed), the sprung speed on the front wheel side. Regardless of the signal of V1, the front wheel gain Gf is set to a constant value. On the other hand, when the vehicle speed V3 is higher than the threshold value Vt (at the time of high vehicle speed), the vehicle body 1 moves downward when the vehicle body 1 vibrates upward (characteristic line 16A in FIG. 4). The front wheel gain Gf is set to a larger value as the vehicle speed V3 becomes higher than when the vehicle vibrates (characteristic line 16B in FIG. 4). The threshold value Vt is obtained experimentally, and is not limited to the exemplified values, but is set as appropriate according to the shape of the vehicle body 1 and the like.

  The rear wheel gain map 17 sets the rear wheel gain Gr based on the signal directions of the vehicle speed V3 and the rear wheel sprung speed V1. Specifically, when the vehicle speed V3 is lower than the threshold value Vt, the rear wheel gain map 17 sets the rear wheel gain Gr to a constant value regardless of the signal of the sprung speed V1 on the rear wheel side. Set to. On the other hand, the rear wheel gain map 17 shows that when the vehicle speed V3 is higher than the threshold value Vt, when the vehicle body 1 vibrates downward (characteristic line 17A in FIG. 5), Compared to when the vehicle vibrates upward (characteristic line 17B in FIG. 5), the rear wheel gain Gr is set to a larger value as the vehicle speed V3 increases.

  The front wheel target damping force calculator 18 calculates a front wheel target damping force DFf based on the front wheel gain Gf and the front wheel sprung speed V1. Specifically, the front wheel target damping force calculator 18 calculates the front wheel target damping force DFf by multiplying the front wheel side sprung speed V1 by the front wheel gain Gf set by the front wheel gain map 16. Here, when the vehicle speed V3 is high, the sprung speed V1 is negative (the vehicle body 1 vibrates downward) when the sprung speed V1 is positive (the vehicle body 1 vibrates upward). The front wheel gain Gf becomes a large value as compared with the above case. Therefore, as shown in FIG. 6, when the vehicle speed V3 is high, the front wheel target damping force DFf on the expansion side (the sprung speed V1 is the positive side) becomes higher and the contraction side (the sprung speed). The front wheel target damping force DFf with V1 on the negative side is low. In other words, the absolute value of the front wheel target damping force DFf is larger on the expansion side (the sprung speed V1 is the positive side) than on the contraction side (the sprung speed V1 is the negative side).

  The rear wheel target damping force calculator 19 calculates a rear wheel target damping force DFr based on the rear wheel gain Gr and the rear wheel sprung speed V1. More specifically, the rear wheel target damping force calculator 19 multiplies the rear wheel side sprung speed V1 by the rear wheel gain Gr set by the rear wheel gain map 17 to obtain the rear wheel target damping force DFr. calculate. Here, when the vehicle speed V3 is high, the sprung speed V1 is positive (the vehicle body 1 vibrates upward) when the sprung speed V1 is negative (the vehicle body 1 vibrates downward). The rear wheel gain Gr becomes a large value as compared with the above case. For this reason, as shown in FIG. 7, when the vehicle speed V3 is high, the rear wheel target damping force DFr is higher on the contraction side (the sprung speed V1 is negative) than when the vehicle speed is low, and on the expansion side (sprung) The rear wheel target damping force DFr becomes lower (the speed V1 is the positive side). In other words, the absolute value of the rear wheel target damping force DFr is larger on the contraction side (the sprung speed V1 is negative) than on the expansion side (the sprung speed V1 is positive).

  The damping force map 20 constitutes an adjustment signal output unit, and outputs a command current value I as an adjustment signal for adjusting the damping force characteristics of the shock absorber 6 based on the target damping forces DFf and DFr and the relative speed V2. As shown in FIG. 8, this damping force map 20 is set based on the test data by the inventors etc. in which the relationship between the target damping force DFf, DFr and the command current value I is variably set according to the relative speed V2. It has been done. The damping force map 20 should be output to the actuator 7 of the front wheel side shock absorber 6 based on the front wheel target damping force DFf from the gain multiplication processing unit 15 and the front wheel side relative speed V2 from the integrator 13. Command current value I is output. The damping force map 20 is applied to the actuator 7 of the shock absorber 6 on the rear wheel side based on the rear wheel target damping force DFr from the gain multiplication processing unit 15 and the rear wheel side relative speed V2 from the integrator 13. The command current value I to be output is output.

  The damping force map 20 outputs an adjustment signal (command current value I) for controlling the shock absorber 6 so that the damping force adjusting shock absorber is adapted to the Skyhook theory. More specifically, when the relative speed V2 is on the positive side (extension side), first, one is selected from a plurality of characteristic lines indicated by solid lines in FIG. 8 according to the magnitude of the relative speed V2. The In FIG. 8, the larger the relative speed V2, the more characteristic line on the right side. Next, the command current value I corresponding to the values of the target damping forces DFf and DFr in the selected characteristic line is obtained. Geometrically, a line is drawn vertically from the values of the target damping forces DFf and DFr to obtain an intersection with the selected characteristic line, and the intersection between the line drawn horizontally and the vertical axis is the command current value I It becomes.

  In this way, when the relative speed V2 is on the positive side (extension side) and the sprung speed V1 is on the positive side (upward side), the command current value I is decreased and attenuated as the target damping forces DFf and DFr increase. Set the force characteristics to hard characteristics (hard characteristics). When the relative speed V2 is on the positive side (extension side) and the sprung speed V1 is on the negative side (downward side), the command current value I remains constant at a large value regardless of the magnitude of the target damping forces DFf and DFr. Set the characteristic to a soft characteristic.

  On the other hand, when the relative speed V2 is on the negative side (contraction side), one is selected from a plurality of characteristic lines indicated by broken lines in FIG. 8 according to the magnitude of the relative speed V2. In FIG. 8, the characteristic line on the left side becomes larger as the relative speed V2 increases. Next, the command current value I corresponding to the values of the target damping forces DFf and DFr in the selected characteristic line is obtained.

  In this way, when the relative speed V2 is on the negative side (contraction side) and the sprung speed V1 is on the positive side (upward side), the command current value I is a large value regardless of the magnitudes of the target damping forces DFf and DFr. The damping force characteristic is set to a soft characteristic. When the relative speed V2 is negative (contraction side) and the sprung speed V1 is negative (downward), the command current value I is decreased as the target damping forces DFf and DFr decrease (increase in the negative direction). Set the damping force characteristics to hard characteristics.

  As described above, the generated damping force of the shock absorber 6 is variably adjusted between hardware and software according to the command current value I supplied to the actuator 7 or variably in a plurality of stages.

  The vehicle suspension control apparatus according to the present embodiment has the above-described configuration. Next, a process for variably controlling the damping force characteristic of the shock absorber 6 using the controller 11 will be described.

  First, when the control process shown in FIG. 10 is started upon receiving power supply accompanying the engine start of the vehicle, the controller 11 is initially set in step 1. Then, in step 2, it is determined whether or not a control cycle of, for example, about 5 to 10 ms has been reached, and the process waits until the control cycle is reached while determining “NO”. On the other hand, when “YES” is determined in Step 2 and the control period is reached, the process proceeds to the next Step 3 to output the control command value (command current value I) calculated in the previous control period to the actuator 7. The actuator 7 of the shock absorber 6 is driven.

  Next, in step 4, in order to input the sensor value, the vibration acceleration in the upward and downward directions on the sprung (vehicle body 1) side is read from the sprung acceleration sensor 8, and the unsprung (wheel 2) is read from the unsprung acceleration sensor 9. The vibration acceleration in the upward and downward directions is read, and the vehicle speed V3 is read from the vehicle speed sensor 10.

  In the next step 5, the ride comfort control process is performed from the obtained information, and the target damping forces DFf and DFr and the relative speed V2 are calculated. Specifically, the integrator 12 of the controller 11 integrates the vibration acceleration detection signal from the sprung acceleration sensor 8 and calculates the sprung speed V1 on the front wheel side and the rear wheel side. Then, the gain multiplication processor 15 calculates the front wheel target damping force DFf and the rear wheel target damping force DFr based on the vehicle speed V3 and the sprung speeds V1 on the front and rear wheels.

  Further, the detection signal from the unsprung acceleration sensor 9 is subtracted from the detection signal from the unsprung acceleration sensor 8 by the subtractor 14 of the controller 11. Then, the integrator 13 integrates the relative acceleration output from the subtractor 14 to calculate the upward and downward relative speed V2 between the vehicle body 1 and the wheel 2.

  Next, at step 6, using the damping force map 20 of the controller 11, a command current value I corresponding to the target damping forces DFf and DFr calculated at step 5 and the relative speed V2 is calculated.

  The command current value I calculated in step 6 drives and controls the actuator 7 of the shock absorber 6 in the next step 3 every time the control period determined as “YES” in step 2 is reached. Used for. Thereby, the damping force characteristic of the shock absorber 6 is continuously controlled by being variable between a hard characteristic (hard characteristic) and a soft characteristic (soft characteristic).

  Thus, according to the present embodiment, the gain multiplication processing unit 15 increases the front wheel target damping force DFf on the expansion side and increases the front wheel target on the contraction side when the vehicle speed V3 by the vehicle speed sensor 10 is high compared to when the vehicle speed V3 is low. Set the damping force DFf low. Further, the gain multiplication processing unit 15 sets the contraction-side rear wheel target damping force DFr higher and the expansion-side rear wheel target damping force DFr lower when the vehicle speed V3 by the vehicle speed sensor 10 is higher than when the vehicle speed V3 is low. To do.

  For this reason, when the vehicle speed is high, the damping force of the shock absorber 6 is controlled so that the front side of the vehicle body 1 is low and the rear side is high. Therefore, as shown in FIG. As a result, at high vehicle speeds where lift is likely to be generated by the airflow, the vehicle behavior is lowered forward, so that the inflow of the airflow to the lower surface of the vehicle body 1 can be reduced and the lifting and pitching of the vehicle body 1 can be reduced.

  Further, the gain setting unit 15A sets the expansion-side front wheel gain Gf higher and the contraction-side front wheel gain Gf lower when the vehicle speed V3 measured by the vehicle speed sensor 10 is higher than when the vehicle speed V3 is low. The wheel target damping force calculator 15B calculates the front wheel target damping force DFf by multiplying the front wheel gain Gf by the gain setting unit 15A and the sprung speed V1 on the front wheel side. For this reason, when the vehicle speed V3 by the vehicle speed sensor 10 is high, the front wheel target damping force DFf on the expansion side can be set higher and the target front wheel damping force DFf on the contraction side can be set lower than when the vehicle speed V3 is low. In other words, the absolute value of the front wheel target damping force DFf is larger on the expansion side (the sprung speed V1 is the positive side) than on the contraction side (the sprung speed V1 is the negative side).

  Further, the gain setting unit 15A sets the rear wheel gain Gr on the expansion side lower and the rear wheel gain Gr on the contraction side higher when the vehicle speed V3 by the vehicle speed sensor 10 is higher than when the vehicle speed V3 is low. The rear wheel target damping force calculator 15B calculates the rear wheel target damping force DFr by multiplying the rear wheel gain Gr by the gain setting unit 15A and the rear wheel sprung speed V1. For this reason, when the vehicle speed V3 by the vehicle speed sensor 10 is high, the rear wheel target damping force DFr on the contraction side can be set higher and the target rear wheel target damping force DFr on the extension side can be set lower than when the vehicle speed V3 is low. In other words, the absolute value of the rear wheel target damping force DFr is larger on the contraction side (the sprung speed V1 is negative) than on the expansion side (the sprung speed V1 is positive).

  In the above-described embodiment, the vehicle body side vertical speed detection unit is configured using the sprung acceleration sensor 8 and the integrator 12. However, the vehicle body 1 side upward and downward speeds (sprung speed V1) are directly measured. The vehicle body side vertical speed detection unit may be configured by using a sprung speed sensor that detects the speed of the vehicle.

  In the above-described embodiment, the relative speed detection unit is configured using the sprung acceleration sensor 8, the unsprung acceleration sensor 9, the subtractor 14, and the integrator 13. However, the sprung speed sensor, the unsprung speed sensor, and the subtractor are used. The relative speed detection unit may be configured by using a speed sensor that directly detects the relative speed V2 between the vehicle body 1 and the wheel 2. You may comprise a relative speed detection part with the displacement sensor and differentiator which detect the relative displacement between the wheels 2. FIG.

  In the above-described embodiment, the configuration in which the signal from the vehicle speed sensor 10 is directly input to the controller 11 is exemplified. However, the controller 11 may acquire the vehicle speed V3 via a CAN (Controller Area Network) or the like.

  In the above embodiment, the gain setting unit 15A (the front wheel gain map 16, the rear wheel gain map 17) determines whether or not the vehicle speed is at a high vehicle speed depending on whether or not the vehicle speed V3 is higher than a certain threshold value Vt. Is determined. However, the present invention is not limited to this. For example, the threshold value is changed according to the lift acting on the vehicle, and it is determined whether the vehicle speed is high or not according to whether the speed is higher than the variable threshold value. May be.

  In the above embodiment, the gain multiplication processing unit 15 is configured to calculate the target damping forces DFf and DFr by multiplying the sprung speed V1 by the front wheel gain Gf and the rear wheel gain Gr, but the gain Gf, It is not necessary to multiply the sprung speed V1 by Gr. For example, the target damping forces DFf and DFr that have nonlinear characteristics with respect to the sprung speed V1 are calculated based on the gains Gf and Gr and the sprung speed V1, for example. Also good.

  In the above embodiment, the front wheel gain Gf and the rear wheel gain Gr are changed in proportion to the vehicle speed V3 at high vehicle speeds. However, the present invention is not limited to this. For example, the front wheel gain Gf and the rear wheel gain Gr may be changed in two stages at high vehicle speed and low vehicle speed, or may be changed in three or more stages. It is good also as a structure changed not only in steps but with arbitrary nonlinear characteristics.

  In the above-described embodiment, the gain multiplication processing unit 15 sets the expansion-side front wheel target damping force DFf higher and the contraction-side front wheel target damping force DFf lower when the vehicle speed V3 is higher than when the vehicle speed V3 is low. In addition, the rear-wheel target damping force DFr on the expansion side is set low and the rear-wheel target damping force DFr on the contraction side is set high. However, the present invention is not limited to this. For example, when the vehicle speed V3 is high, the front wheel target damping force DFf on the expansion side is set higher and the front wheel target damping force DFf on the contraction side is set lower than when the vehicle speed V3 is low. The target damping force DFr may be set the same as when the speed is low. Further, when the vehicle speed V3 is high, the expansion-side rear wheel target damping force DFr is set lower and the contraction-side rear wheel target damping force DFr is set higher than when the vehicle speed V3 is low, and the front wheel target damping force DFf is low. The same setting may be used.

  Therefore, the gain setting unit 15A is not limited to adjusting both the front wheel gain Gf and the rear wheel gain Gr according to the vehicle speed V3, and may adjust only the front wheel gain Gf. It is good also as a structure which adjusts only Gr.

  Furthermore, in the above-described embodiment, the case where the present invention is applied to the controller 11 that controls the shock absorber 6 of the suspension device 4 based on the Skyhook theory has been described as an example, but the controller that performs roll feedback control and pitch feedback control is described. It is good also as composition to apply.

DESCRIPTION OF SYMBOLS 1 Car body 2 Wheel 4 Suspension device 5 Spring 6 Damping force adjustment type shock absorber 7 Actuator 8 Sprung acceleration sensor 9 Unsprung acceleration sensor 11 Controller 12, 13 Integrator 14 Subtractor 15 Gain multiplication processing unit (damping force calculation unit)
15A Gain setting unit 15B Front wheel / rear wheel target damping force calculator 20 Damping force map (adjustment signal output unit)

Claims (2)

In a suspension control device including a damping force adjustment type shock absorber that is interposed between a vehicle body and a wheel of a vehicle and that adjusts damping force characteristics using an adjustment signal,
A vehicle body side vertical speed detector that detects the vehicle body vertical speed as the vehicle body vertical speed, and the damping force adjustment type shock absorber is generated based on the vehicle body vertical speed by the vehicle body vertical speed detector. A damping force calculation unit that calculates a target damping force, a relative speed detection unit that detects an upper and lower relative speed between the vehicle body and the wheel, and a target damping force and the relative speed detection by the damping force calculation unit An adjustment signal output unit that outputs an adjustment signal for adjusting the damping force characteristic of the damping force adjusting shock absorber based on the relative speed by the unit, and a vehicle speed detection unit that detects the traveling speed of the vehicle as a vehicle speed,
The damping force calculation unit sets the target damping force on the expansion side of the front wheels to be lower and the target damping force on the contraction side to be lower when the vehicle speed by the vehicle speed detection unit is high than when the vehicle speed is low, and / or A suspension control device characterized in that the target damping force on the expansion side of the wheel is set low and the target damping force on the contraction side is set high. The damping force calculation unit includes a gain setting unit that sets a front wheel gain and a rear wheel gain based on a vehicle speed by the vehicle speed detection unit, and the front wheel gain and the vehicle body side vertical speed by the gain setting unit. Front wheel / rear wheel that calculates the target damping force on the front wheel side by multiplying and calculates the target damping force on the rear wheel side by multiplying the gain for the rear wheel by the gain setting unit and the vehicle body side vertical speed A target damping force calculator,
The gain setting unit sets the front wheel gain on the expansion side lower and the front wheel gain on the contraction side lower than the low speed when the vehicle speed detected by the vehicle speed detection unit is high. The suspension control device according to claim 1, wherein the suspension gain control device is configured such that the wheel gain is set low and the rear wheel gain on the contraction side is set high.

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