JP2007203831A - Suspension control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suspension control device capable of improving control effect in unspring vibration control. <P>SOLUTION: In the case wherein a determination whether unspring acceleration (unsprung movement condition of a vehicle) from an unspring acceleration sensor is a predetermined unspring acceleration or more (excessive-vibration condition) or not is done and wherein the unspring acceleration at the predetermined unspring acceleration or less is determined, operation range of an actuator is limited within a limited time current range LH. Even if the actuator (a shock absorber) is controlled by using an unspring action signal containing a high frequency component, since operation range of the actuator is reduced, following ability is improved by reduction of the operation range, and the shock absorber can be controlled in good response to movement condition of a vehicle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a suspension control device including a damping characteristic reversing type shock absorber used for vehicles such as automobiles and railway vehicles.

Conventionally, as an example of a suspension control device provided with a damping characteristic reversal type shock absorber, there is a suspension control device disclosed in Patent Document 1.
This suspension control device, for example, in the case of over-sprung (vehicle body) vibration suppression, suppresses pushing the vehicle body upward with the contraction side as a soft characteristic when the swell is projected upward, and at this time, the expansion side is hard. Due to the characteristic, when the swell is lowered thereafter, the vehicle body facing upward is pulled downward by the weight on the axle side, thereby making the vehicle body flat. In addition, the piston speed (relative speed) is estimated from the sprung vertical acceleration to suppress unsprung vibration (unsprung riot), and high-frequency noise for passengers caused by unsprung vibration (unsprung sway). And a decrease in tire ground contact property (and hence a decrease in steering stability during cornering).

JP 2002-321513 A

  In general, unsprung vibration (unsprung fluctuation) has a frequency in the vicinity of about 10 to 15 Hz (unsprung resonance frequency), and vibration generated on the spring has a frequency in the vicinity of about 1 Hz. In the above prior art, the unsprung vibration is suppressed based on the sprung vertical acceleration. However, the actuator operation cannot follow the movement change of the vehicle, and the change of the damping characteristic of the shock absorber is likely to be delayed. In practice, there was room for improvement. Note that performing vibration suppression control based on unsprung vertical acceleration instead of sprung vertical acceleration is more undesirable because unsprung vibration (unsprung vertical acceleration) is a high frequency as described above.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a suspension control device capable of improving the control effect of unsprung vibration control.

The invention according to claim 1 is provided between the sprung and unsprung parts of the vehicle. Among the damping characteristics on the expansion side and the contraction side, when the damping characteristic on one side is soft, the damping characteristic on the other side is soft. When the other side of the damping characteristic is soft, the damping characteristic of the one side is adjusted between soft and hard. An actuator that adjusts the damping characteristic of the damping characteristic inversion type shock absorber according to the supply current, and a control means that controls the damping characteristic inversion type shock absorber by controlling the supply of current to the actuator in accordance with the motion state of the vehicle And an unsprung motion state detecting means for detecting the unsprung motion state of the vehicle, the unsprung motion state detecting hand. There when motion state unsprung detected is determined to be over-vibration state, and limits the operating range of the actuator.
According to a second aspect of the present invention, in the suspension control device according to the first aspect, the determination that the unsprung motion state is an overvibration state, and the data relating to the unsprung vertical acceleration has exceeded a predetermined value. It is characterized by performing by.

According to a third aspect of the present invention, in the suspension control device according to the first aspect, the determination that the unsprung motion state is an overvibration state is made based on a determination result of a road surface state determination unit that determines a road surface state. It is characterized by being performed.
According to a fourth aspect of the present invention, in the suspension control device according to any one of the first to third aspects, the damping characteristic reversal type shock absorber is extended without the actuator being subjected to the restriction on the operating range. Hard shrink soft, stretch soft soft and stretch soft shrink hard characteristic current range, stretch soft shrink current characteristic range, stretch soft shrink current characteristic range, stretch soft shrink soft characteristic current range Thus, the expansion hard contraction soft characteristic current range and the expansion / contraction soft characteristic current range are set.

According to the first to fourth aspects of the present invention, when it is determined that the unsprung motion state of the vehicle is an over-vibration state, the operating range of the actuator is limited. Even if the actuator is controlled using, vibration can be suppressed with good followability.
According to the second aspect of the present invention, the determination that the unsprung motion state is an over-vibration state is made by exceeding the data predetermined value relating to the unsprung vertical acceleration. Therefore, the determination can be easily performed. it can.
According to the third aspect of the present invention, the determination that the unsprung motion state is an excessive vibration state is made based on the determination result of the road surface state determination means for determining the road surface state, so that the determination accuracy is improved. Can be achieved.

  Hereinafter, a suspension control apparatus 1 according to a first embodiment of the present invention will be described with reference to FIGS. In FIG. 1, a vehicle body 3 (sprung) and four (only one is shown in the figure) wheel 4 side (an unsprung member (an axle shock absorber mounting bracket or the like)) constituting an automobile 2 (vehicle). A spring 5 and a shock absorber 6 (damping characteristic reversal type shock absorber) capable of adjusting the damping characteristic are interposed in parallel with each other (unsprung), and these support the vehicle body 3. Yes. A piston 7 is movably accommodated in the shock absorber 6, a piston rod 8 connected to the piston 7 is held by the vehicle body 3, and the shock absorber 6 is held on the wheel 4 side (shock absorber mounting bracket or the like).

The vehicle body 3 has a vertical acceleration (sprung vertical acceleration) relative to the absolute coordinate system of the vehicle body 3 (hereinafter referred to as a sprung acceleration for convenience). A sprung acceleration sensor 9u (sprung vertical acceleration detecting means) for detecting αu is attached. On the wheel 4 side, vertical acceleration (unsprung vertical acceleration) with respect to the absolute coordinate system on the wheel 4 side (hereinafter referred to as unsprung acceleration for convenience). An unsprung acceleration sensor 9d (unsprung vertical acceleration detecting means) for detecting αd is attached.
The sprung acceleration αu (detection signal) detected by the sprung acceleration sensor 9u and the unsprung acceleration αd (data relating to the unsprung vertical acceleration) detected by the unsprung acceleration sensor 9d are supplied to the controller 10 (control means). .

  Four shock absorbers 6 and four springs 5 are provided corresponding to the four wheels 4, but only one of them is shown for convenience. Further, one or two sets of sprung and unsprung acceleration sensors 9u and 9d are provided on the front wheel side, and at least one set of sprung and unsprung acceleration sensors 9u and 9d are provided on the rear wheel side. For convenience, only one set is shown. Reference numeral 11 denotes an actuator which is activated by receiving an input of a current I adjusted by a control signal A, which will be described later, and causes the shock absorber 6 to generate a damping force (target damping force) corresponding to the control signal A (current I). I am doing so.

As shown in FIGS. 5 and 6, the shock absorber 6 adjusts the expansion side damping characteristic between hard and soft when the contraction side damping characteristic is soft, and the expansion side damping characteristic is soft. In this case, the contraction-side damping characteristic is adjusted between soft and hard, and the contraction-side damping characteristic and the stretching-side damping characteristic are reversed [elongation hard (H ) / Shrinking software (S), stretching software (S) / shrinking software (S) or stretching software (S) / shrinking hardware (H)].
5 and 6 show the damping characteristics of the shock absorber 6 with the horizontal axis representing the current I received by the actuator 11 and the vertical axis representing the contraction and expansion side damping forces. When the actuator 11 is not subject to the limitations described later, as shown in FIG. 5, the current I ranges from the current value Ib to the current value Ic (Ib <Ic) (hereinafter referred to as a non-restricted use current range NLH). ) Current. The current value in the substantially middle portion of the non-restricted operating current range NLH is Ia (Ib <Ia <Ic).

In the first embodiment, when it is determined that the unsprung motion state detected by the lower acceleration sensor 9d and the unsprung state determination unit 50 (unsprung motion state detection means) is an overswing state, the actuator 11 is limited. Here, the operation range of the actuator 11 will be described with reference to FIGS. 5 and 6.
As shown in FIG. 5, the actuator 11 is in a state where it is not subject to the restriction (including during normal travel), and its operating range (non-restricted working current range NLH) is extended when the shock absorber 6 is extended and hard (H) is reduced. (S) damping characteristics, stretching / shrinking soft (S) damping characteristics, and stretching soft (S) shrinking hard (H) damping characteristics, respectively, an expansion hard contraction soft characteristic current range R1, an expansion / contraction soft characteristics current range R2, Elongation soft shrinkage hard characteristic current range R3.
The expansion hard contraction soft characteristic current range R1 corresponds to “a range from the current value Ib to a value in the vicinity of the current value Ia (a value slightly smaller than the current value Ia)” in the current I.
The expansion / contraction soft characteristic current range R2 and current I correspond to “the vicinity thereof including the current value Ia”.
The expansion soft contraction hard characteristic current range R3 corresponds to “a range from a value in the vicinity of the current value Ia (a value slightly larger than the current value Ia) to the current value Ic” in the current I.
On the other hand, by receiving the restriction, the operating range of the actuator 11 is limited to a limited use current range LH composed of an expansion hard contraction soft characteristic current range R1 and an extension soft contraction current characteristic R2, as shown in FIG. The
A controller 10 is connected to the sprung acceleration sensor 9u, the unsprung acceleration sensor 9d, and the actuator 11.

As shown in FIG. 2, the controller 10 receives the sprung acceleration αu of the vehicle body 3 detected by the sprung acceleration sensor 9u, generates a skyhook command signal B, and outputs the skyhook command signal B. The unsprung acceleration αd of the vehicle body 3 detected by the control calculation unit 12 (sprung vibration suppression signal calculating means) and the unsprung acceleration sensor 9u and unsprung acceleration sensor 9d is input, and the unsprung acceleration αd is determined from the unsprung acceleration αu. Relative acceleration calculator 25 for calculating relative acceleration αs by subtracting the value, and unsprung vibration damping command signal C to be generated and unsprung vibration damping command signal C to be output. And a control calculation unit 13 (unsprung vibration suppression signal calculation means).
The controller 10 further selects either the skyhook command signal B or the unsprung vibration suppression command signal C according to the motion state of the vehicle, and outputs the selected signal as the control signal A. An acceleration sensor 9d, a control signal output unit 14, an actuator, and the excessive vibration state determination unit 50 connected to a power supply unit that supplies current.

  The overvibration state determination unit 50 receives an input of the unsprung acceleration αd (indicating the unsprung motion state) from the unsprung acceleration sensor 9d, and determines whether or not the unsprung motion state is the overswing state. When the determination is made and it is determined that the unsprung motion state is an over-vibration state, the operation current range of the actuator 11 for the operating range of the actuator 11 that is the non-restriction use current range NLH in the determined normal running state. Limited to LH.

Further, based on the control signal A, the excessive vibration state determination unit 50 has a magnitude corresponding to the control signal A so that the current from the power supply unit 51 becomes a value within the operating range of the actuator 11 determined as described above. Current I is obtained, and this current I is supplied to the actuator 11. The actuator 11 causes the shock absorber 6 to generate a damping force corresponding to the current I (control signal A).
In other words, the excessive vibration state determination unit 50 performs determination and processing as follows. That is, when the unsprung state determination unit 50 does not determine that the unsprung motion state is an overswing state (including a normal running state), as illustrated in FIG. 5, a current ( Ib to Ic) are supplied to the actuator 11, and when it is determined that the unsprung motion state is an overvibration state, as shown in FIG. 6, the current corresponding to the limited use current range LH (Ib to approximately Ia) Is supplied to the actuator 11.
In the present embodiment, the over-vibration state determination unit 50 and the unsprung acceleration sensor 9d constitute unsprung motion state detection means.

As shown in FIG. 2, the skyhook control calculation unit 12 integrates the sprung acceleration αu from the sprung acceleration sensor 9 u to obtain a vertical speed (absolute speed) V, and a predetermined value for the speed V. An amplification circuit 16 that obtains a signal D by multiplying the magnitude of the control gain Ku, and a skyhook command signal B having a magnitude corresponding to the signal D obtained by the amplification circuit 16 is obtained and this skyhook command signal B is obtained as a control signal output unit. 14 and a skyhook command signal output unit 17 that outputs to 14.
The unsprung vibration suppression control calculation unit 13 receives an input of the relative acceleration αs and passes a high-pass filter 26 that passes a high-frequency component of 10 Hz or more, and receives a high-frequency signal that passes the high-pass filter 26 and passes a low-frequency component of 15 Hz or less. A low-pass filter 20 to be amplified, an amplification circuit 21 that amplifies by multiplying the signal control gain Kd that passes through the low-pass filter 20 and obtains an unsprung vibration suppression command calculation signal PD, and converts the output signal from the amplification circuit 21 An unsprung vibration suppression command signal output unit 33 that performs processing to obtain an unsprung vibration suppression command signal C and outputs the unsprung vibration suppression command signal C to the control signal output unit 14;

The operation of the suspension control apparatus 1 configured as described above will be described based on the flowcharts of FIGS. 3 and 4 and the control state diagram of FIG.
As shown in FIG. 3, when the controller 10 receives power supply by starting a vehicle engine (not shown) or the like (step S1), the controller 10 first performs initialization (step S2) to determine whether or not the control cycle has been reached. Determine (step S3). In step S3, it is repeatedly determined whether or not the control cycle has been reached until it is determined that the control cycle has been reached.

  If it is determined in step S3 that the control cycle has been reached, the content calculated in the previous control cycle is output to the actuator 11 to drive it (step S4). Subsequently, a signal corresponding to another port such as an LED is output (step S5). Next, detection signals are read from the sprung and unsprung acceleration sensors 9u, 9d, etc. (step S6). Subsequently, a control calculation subroutine is executed based on the read information in step S6 (step S7).

In the control calculation subroutine of step S7, as shown in FIG. 4, the control amount calculation is performed by the relative acceleration calculation unit 25, the skyhook control calculation unit 12, and the unsprung vibration suppression control calculation unit 13, and the skyhook command signal B And the unsprung vibration suppression command signal C are supplied to the control signal output unit 14, and one of the skyhook command signal B and the unsprung vibration suppression command signal C is selected based on the motion state of the vehicle (during normal driving). A skyhook command signal B is output, and an unsprung vibration command signal C is output when the unsprung vibration becomes relatively large, such as when the unsprung acceleration is large or when driving on a rough road. Is output from the control signal output unit 14 to the excessive vibration state determination unit 50 (step S11).
Next, or together with the process of step S11, the controller 10 (excessive vibration state determination unit 50) receives an input of the unsprung acceleration αd detected by the unsprung acceleration sensor 9d, and accordingly, from a storage unit (not shown) A predetermined unsprung acceleration αd0 (to be used as a comparison reference) stored in advance in the storage unit is read (step S12).

Next, the controller 10 (excessive vibration state determination unit 50) determines whether or not the unsprung acceleration αd from the unsprung acceleration sensor 9d is equal to or greater than a predetermined unsprung acceleration αd0 (and thus the unsprung motion state of the vehicle is an excessive vibration state). Whether or not) (step S13).
If it is determined NO in step S13 (the unsprung acceleration αd is less than the predetermined unsprung acceleration αd0), the operating range of the actuator 11 is set to a non-restricted operating current range NLH (of currents Ib to Ic as shown in FIG. 5). The current I having a magnitude corresponding to the control signal A so as to be a value within the unrestricted operating current range NLH, and supplying the current I to the actuator 11 to the shock absorber 6 A damping force corresponding to the current I is generated.

  Further, when it is determined YES in step S13 (the unsprung acceleration αd is equal to or greater than the predetermined unsprung acceleration αd0), the operating range of the actuator 11 is set to the limited use current range LH (current Ib˜approximately) as shown in FIG. The current I having a magnitude corresponding to the control signal A so as to be a value within the limited use current range LH, and supplying this current I to the actuator 11 to the shock absorber 6. A damping force corresponding to the current I is generated.

In the present embodiment, the spring force is determined by determining whether or not the unsprung acceleration αd (the unsprung motion state of the vehicle) from the unsprung acceleration sensor 9d is equal to or greater than a predetermined unsprung acceleration αd0 (excessive vibration state). When it is determined that the lower acceleration αd is equal to or greater than the predetermined unsprung acceleration αd0 (excessive vibration), the operating range of the actuator is limited to the limited use current range LH as shown in FIG. The current value of I is limited as shown by the solid line JS in FIG.
Therefore, according to the suspension control device 1 according to the present embodiment, the unsprung resonance frequency is as high as about 10 to 15 Hz, and even if this high-frequency component signal is used for control, as described above, the spring When the lower acceleration αd is determined to be equal to or greater than the predetermined unsprung acceleration αd0 (excessive vibration state), the operating range of the actuator 11 is limited to the limited use current range LH as shown in FIG. Vibration can be suppressed with a good followability.

  That is, if the actuator 11 is to be controlled using an unsprung behavior signal including a high-frequency component, if the operating range of the actuator 11 is the non-restricted operating current range NLH, the operating range of the actuator 11 is wide. Therefore, it is difficult to control the actuator 11 (and consequently the shock absorber 6) by quickly following the change in the motion state of the vehicle, and the response is inferior. As a result, when the actuator 11 is operating with the current in the extended hard contracted soft characteristic current range R1, it is necessary to operate with the current in the extended soft contracted hard characteristic current range R3 depending on the motion state of the vehicle. Even if a signal is output, the motion state of the vehicle is expanded until the signal is output, and the vehicle changes to a state in which the operation with the current in the soft characteristic current range R1 is necessary. It was possible that the vibration would promote the vibration.

On the other hand, as described above, when it is determined that the unsprung acceleration αd is equal to or greater than the predetermined unsprung acceleration αd0 (excessive vibration state), the operating range of the actuator 11 is not limited as shown in FIG. By limiting to the working current range NLH, vibration can be suppressed with good followability.
FIG. 7B shows the current value of the current I supplied to the actuator 11 when the operating range of the actuator 11 is not limited, corresponding to the solid line JS (when the operating range of the actuator 11 is limited). Shown by dotted line TS. FIG. 7A shows an example of unsprung acceleration αd that is the source of current generation in FIG. 7B.
In the first embodiment, the case where the data related to the unsprung vertical acceleration is the unsprung acceleration αd is taken as an example. However, the data related to the unsprung vertical acceleration is not limited to this, and the change in the unsprung acceleration αd. Rate may be used.

  Next, a suspension control apparatus 1A according to a second embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 8, the suspension control device 1A according to the second embodiment is provided with a controller 10A in place of the controller 10 as compared to the suspension control device 1A according to the first embodiment. However, the main difference is that the control calculation execution subroutine S7A (FIG. 10) is executed instead of the control calculation execution subroutine S7 (FIG. 4) of FIG. In addition, about the member and part equivalent to the member and part shown in FIGS. 1-7, the same code | symbol is used and the description is abbreviate | omitted suitably.

  As shown in FIG. 8, the controller 10 </ b> A includes a road surface determination unit 30 that detects a road surface state (swell road, normal road, bad road, and extremely bad road) based on the sprung acceleration αu, and the road surface determination unit 30 is in a road surface state. A road surface determination map storage unit 32 that stores in advance a road surface determination map 31 used for determination. The controller 10A includes a signal adjustment unit 50 that replaces the excessive vibration state determination unit 50 included in the controller 10 (FIG. 2). In the controller 10, the unsprung acceleration αd from the unsprung acceleration sensor 9 d is input to the overvibration state determination unit 50, but in the controller 10 A, instead of this, determination result information indicating the determination result performed by the road surface determination unit 30. dk is input to the signal adjustment unit 50.

When the determination result information dk from the road surface determination unit 30 is the content that the road surface (traveling road) is a terrible road, the signal adjustment unit 50 is set to the normal non-restricted use current range NLH. The operating range of the actuator 11 is limited to the limited use current range LH.
Further, based on the control signal A, the excessive vibration state determination unit 50 has a magnitude corresponding to the control signal A so that the current from the power supply unit 51 becomes a value within the operating range of the actuator 11 determined as described above. Current I is obtained, and this current I is supplied to the actuator 11. The actuator 11 causes the shock absorber 6 to generate a damping force corresponding to the current I (control signal A).
In other words, if the signal adjustment unit 50 does not determine that the unsprung motion state is an over-vibration state (including normal travel), the signal adjustment unit 50 corresponds to the unrestricted use current range LH as shown in FIG. Current (Ib to Ic) is supplied to the actuator 11. Further, when the over-vibration state determination unit 50 determines that the unsprung motion state is an over-vibration state, as illustrated in FIG. 6, the over-vibration state determination unit 50 generates a current (Ib to approximately Ia) corresponding to the limited use current range LH. Supply to the actuator 11.
In the present embodiment, the road surface determination unit 30 and the unsprung acceleration sensor 9d constitute unsprung motion state detection means.

  As shown in FIG. 9, the road surface determination map 31 of the road surface determination map storage unit 32 sets the road as an extremely bad road when the acceleration frequency is in the range of middle to high and the acceleration amplitude is in the range of middle to high. When the frequency is in the range of low to middle and the acceleration amplitude is in the range of middle to high, the road is a wavy road, and the acceleration frequency is in the range of low to middle, excluding the wavy road. In some cases, the road is a normal road.

In the suspension control device 1A, the control amount is calculated by the relative acceleration calculation unit 25, the skyhook control calculation unit 12, and the unsprung vibration suppression control calculation unit 13, as shown in FIG. 10, in the control calculation subroutine (step S7A). Thus, the skyhook command signal B and the unsprung vibration suppression command signal C are supplied to the control signal output unit 14, and one of the skyhook command signal B and the unsprung vibration suppression command signal C is based on the motion state of the vehicle. The selected control signal A is output from the control signal output unit 14 to the excessive vibration state determination unit 50 (step S21).
Next, or together with the process of step S11, the controller 10A (road surface determination unit 30) receives the input of the sprung acceleration αu detected by the sprung acceleration sensor 9u, and in accordance with this, the road surface determination map is stored from the storage unit 32. 31 is read (step S22).

Next, the controller 10A (road surface determination unit 30) compares the sprung acceleration αu with the road surface determination map 31, and determines whether or not the traveling road is a villainous road (a road surface that is unsprung) (step S23). If the determination result indicates that the target road is not a terrible road, it is determined NO in step S23, step S14 described above is executed, this subroutine is terminated, and the process returns to the main routine of FIG.
Further, if the determination result in step S23 is the content indicating that the traveling road is a terrible road, if it is determined YES in step S23, step S15 described above is executed, this subroutine is terminated, and the main process of FIG. Return to the routine.

In this second embodiment, the villainous road is determined using the sprung acceleration αu from the sprung acceleration sensor 9u to determine whether or not the road is a villainous road, and it is determined that the road is a villainous road. As shown in FIG. 6, it is limited to the limited use current range LH, and the current value of the current I supplied to the actuator is limited as shown by the solid line in FIG. 7B, so that it is the same as in the first embodiment. In addition, vibration can be suppressed with good followability.
In the second embodiment described above, the road surface state is estimated using the value of the sprung acceleration sensor 9u. However, the present invention is not limited to this, and the road surface state is estimated using the value of the unsprung acceleration sensor 9d. Also good.

It is a figure showing typically the suspension control device concerning a 1st embodiment of the present invention. FIG. 2 is a block diagram schematically showing the controller of FIG. 1. It is a flowchart (main routine) which shows the control content of the controller of FIG. It is a flowchart which shows the content of the control calculation subroutine of FIG. FIG. 2 is a diagram illustrating an unrestricted operating current range of the actuator of FIG. 1 together with a current-damping force characteristic of the shock absorber of FIG. 1. FIG. 2 is a diagram showing a current range during restriction of the actuator of FIG. 1 together with a current-damping force characteristic of the shock absorber of FIG. 1. 1 is used to determine the operating range of the actuator using the current waveform (B) when the operating range of the actuator of FIG. 1 is the non-limiting operating current range (FIG. 5) and the limiting operating current range (FIG. 6). It is a wave form diagram shown typically with acceleration (A). It is a block diagram which shows typically the controller used for the suspension control apparatus which concerns on 2nd Embodiment of this invention. It is a figure which shows the road surface determination map memorize | stored in the memory | storage part of FIG. It is a flowchart which shows the content of the control arithmetic subroutine which the controller of FIG. 8 performs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1A ... Suspension control apparatus, 6 ... Shock absorber (damping characteristic reversal type shock absorber), 9d ... Unsprung acceleration sensor (Unsprung motion state detection means), 10, 10A ... Controller, 30 ... Road surface judgment part (Unsprung) Motion state detection means), 50 ... spring over-vibration state determination unit (unsprung motion state detection means), NLH ... non-limit use current range, LH ... limit use current range, R1 ... extension hard contraction soft characteristic current range, R2 ... Elongation / contraction soft characteristic current range, R3 ... Elongation soft / shrinkage hard characteristic current range.

Claims (4)

It is provided between the sprung and unsprung parts of the vehicle, and when the damping characteristic on one side is soft, the damping characteristic on the other side is adjusted between soft and hard. When the damping characteristic on the other side is soft, the damping characteristic inversion type shock absorber in which the damping characteristic on one side is adjusted between soft and hard, and
An actuator that operates by receiving a current supply, and adjusts the damping characteristic of the damping characteristic inversion shock absorber according to the supplied current;
A suspension control device comprising: control means for controlling a damping characteristic reversal type shock absorber by controlling supply of a current to the actuator according to a motion state of the vehicle;
An unsprung motion state detecting means for detecting a unsprung motion state of the vehicle;
A suspension control device that limits the operating range of the actuator when it is determined that the unsprung motion state detected by the unsprung motion state detection means is an overvibration state.   The suspension control device according to claim 1, wherein the determination that the unsprung motion state is an over-vibration state is made when data relating to the unsprung vertical acceleration exceeds a predetermined value.   The suspension control device according to claim 1, wherein the determination that the unsprung motion state is an excessive vibration state is made based on a determination result of a road surface state determination unit that determines a road surface state. In the state where the actuator is not subject to the limitation on the operating range, the damping characteristic reversal type shock absorber has a stretching hard contraction soft characteristic current which indicates the damping characteristics of the expansion hard contraction soft, the expansion contraction soft and the extension soft contraction hard, respectively. The range, the expansion / contraction soft characteristic current range, and the expansion soft contraction hard characteristic current range are set, and the expansion hard contraction soft characteristic current range and the expansion / contraction soft characteristic current range are determined by receiving the restriction. 4. The suspension control device according to any one of items 1 to 3.

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