JP2012051424A - Suspension control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the ride quality of a vehicle by adequately controlling the damping force characteristics even during the step ride-over by only a single wheel.SOLUTION: When it is determined that the left sprung speed and the right sprung speed are in the same phase, it is determined that the step ride-over is executed by only single wheel on the wheel side in which the sprung speed is higher. By setting the roll FB control quantity by multiplying the roll speed by the predetermined gain, the damping force characteristic is changed to the hard side. On the other hand, in the wheel in which the sprung speed is lower, it is determined that the step ride-over is not executed, and the roll FB control quantity is not set, and the damping force characteristic is not changed to the hard side, but kept to the soft side. In other words, on the wheel side in which any step ride-over is not executed, the damping force characteristic of the damping force variable damper is controlled so as to maintain the previous damping force command signal.

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.

  Generally, in a vehicle such as a four-wheeled vehicle, a damping force adjustment type shock absorber is provided between the vehicle body side and each wheel side. In addition, a suspension control device configured to variably control the damping force characteristics of the respective shock absorbers according to the vehicle posture during traveling or the like is mounted (for example, see Patent Document 1).

  This type of suspension control device according to the prior art responds to the lateral acceleration and / or the front and rear acceleration of the vehicle in order to suppress the change in posture caused by, for example, the steering operation and braking operation of the vehicle and to ensure running stability. The damping force characteristics of the shock absorbers of each wheel are variably controlled. For example, when a vehicle roll rate is detected by a signal from a lateral acceleration sensor or the like, each shock absorber provided on the left and right wheels has a roll rate so that the damping force characteristics are opposite in phase to the left and right. A command signal that is multiplied by a gain is output, thereby suppressing rolling of the vehicle.

  In addition, it is determined that vibrations caused by “aori” corresponding to the resonance frequency on the vehicle body side and vibrations caused by rolling or pitching on the vehicle body side are different vibration modes, and the damping force characteristics of each shock absorber are variably controlled. A configuration in which the control gain is changed according to the determination result is also known (for example, see Patent Document 2).

JP-A-8-2231 JP-A-8-40034

  By the way, in the prior art according to Patent Document 1, for example, when vibrations in the left and right directions of the vehicle are detected as roll rates, the shock absorbers provided on the left and right wheels side have a damping force characteristic on the left, It is configured to output a command signal obtained by multiplying the roll rate by a gain so as to be in reverse phase on the right. For this reason, even when only one of the left and right wheels gets over the road level difference (for example, when roll resonance occurs at a frequency of about 2 to 3 Hz), the shock absorber for each wheel May output a command signal so that the damping force characteristics are opposite in phase on the left and right, and as a result, the damping force may be hardened even on the side of the wheel with small fluctuations, and the ride comfort of the vehicle may be deteriorated.

  Further, the prior art according to Patent Document 2 discriminates and controls the vibration caused by “aori” corresponding to the resonance frequency on the vehicle body side (for example, a frequency of 10 or more Hz) and the vibration caused by rolling or pitching on the vehicle body side. In this case as well, it is difficult to stop the vibration on the spring when stepping over only one wheel, and the ride comfort of the vehicle may be deteriorated.

  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 properly control the damping force characteristic even when overcoming a step of only one wheel, and to improve the riding comfort of the vehicle. It is an object of the present invention to provide a suspension control device that can perform the above.

  In order to solve the above-described problem, the configuration adopted by the invention of claim 1 is provided with a plurality of damping elements provided between the vehicle body and the plurality of wheels, respectively, and the damping force characteristics are variably adjusted. A force adjustment type shock absorber, a horizontal axis rotation speed detecting means provided on the vehicle body side for detecting a roll rate or a pitch rate of the vehicle body as a horizontal axis rotation speed, and each damping force adjustment according to the horizontal axis rotation speed And a controller for variably controlling the damping force characteristic of the shock absorber, wherein the horizontal axis rotational speed detecting means includes two damping members spaced apart from each other in the horizontal direction of the vehicle body among the plurality of damping force adjusting shock absorbers. The first and second upper and lower speed detecting means for detecting the upper and lower speeds of the vehicle body in the vicinity of the force adjusting shock absorber are configured, and the controller includes the first and second upper, By lower speed detection means Phase determining means for determining whether the two upper and lower speeds are in phase or not, and the one having the smaller upper and lower speeds when the two phases are determined to be in phase by the phase determining means And a damping force characteristic maintaining means for maintaining the damping force characteristic of the damping force adjustment type shock absorber.

  As described above, according to the first aspect of the present invention, it is determined that the step over the step of only one wheel is the same phase. In this case, the damping force adjustment type shock absorber having the smaller upper and lower speeds out of the two locations. By maintaining the damping force characteristic, it is possible to properly control the damping force characteristic and improve the riding comfort of the vehicle.

1 is a perspective view showing a four-wheeled vehicle to which a suspension control device according to a first embodiment of the present invention is applied. It is a control block diagram which shows the structure of a suspension control apparatus. It is a flowchart which shows the damping force control process of each wheel by the controller in FIG. It is a flowchart which concretely shows the control arithmetic processing in step 6 in FIG. It is a map figure which shows the roll state judgment map in the left and right wheels. It is a characteristic diagram which shows the relationship between the upper and lower speed on a spring used in 2nd Embodiment, and roll FB gain. It is a flowchart which actualizes and shows the control arithmetic processing by 2nd Embodiment. It is a characteristic diagram which shows the simulation result when only the left-wheel side gets over a level | step difference at the time of a rough road driving | running | working.

  Hereinafter, a suspension control 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 control device is applied to a four-wheeled vehicle, for example.

  Here, FIG. 1 to FIG. 5 show a first embodiment of the present invention. In the figure, reference numeral 1 denotes a vehicle body constituting a vehicle body. On the lower side of the vehicle body 1, for example, left and right front wheels 2 (only one shown) and left and right rear wheels 3 (only one shown) are shown. Is provided.

  Reference numerals 4 and 4 are front wheel side suspension devices provided between the left and right front wheel 2 sides and the vehicle body 1, and each suspension device 4 includes left and right suspension springs 5 (hereinafter referred to as springs). 5), and left and right damping force adjustable shock absorbers 6 (hereinafter, referred to as semi-active suspensions) formed of a semi-active suspension provided between the left and right front wheels 2 and the vehicle body 1 in parallel with the springs 5 respectively. The damping force variable damper 6).

  7 and 7 are rear wheel side suspension devices provided between the left and right rear wheel 3 sides and the vehicle body 1, and each suspension device 7 includes left and right suspension springs 8 (hereinafter referred to as the left and right suspension springs 8). , Springs 8), and left and right damping force adjustable shock absorbers 9 comprising semi-active suspensions provided between the left and right rear wheels 3 and the vehicle body 1 in parallel with the springs 8). (Hereinafter referred to as a damping force variable damper 9).

  Here, the damping force variable dampers 6 and 9 of the suspension devices 4 and 7 are configured using a damping force adjustable hydraulic shock absorber. The damping force variable dampers 6 and 9 are each composed of a damping force adjusting valve, a solenoid and the like in order to continuously adjust the damping force characteristic from a hard characteristic (hard characteristic) to a soft characteristic (soft characteristic). An actuator (not shown) is attached. Note that the actuator for adjusting the damping force is not necessarily configured to continuously change the damping force characteristic, and may be configured to intermittently adjust in two stages or three or more stages. Further, the damping force variable dampers 6 and 9 only need to be able to switch the damping force, and may be a pneumatic damper or an electromagnetic damper.

  Reference numeral 10 denotes a plurality of sprung and lower acceleration sensors provided on the vehicle body 1. Each of the spring and lower acceleration sensors 10 detects upper and lower vibration accelerations on the vehicle body 1 side, which is the upper side of the spring. In addition, it is attached to the vehicle body 1 at a position near the upper end side (rod protruding end side) of the damping force variable damper 6 on each front wheel 2 side, and is also attached to the vehicle body 1 at an intermediate position between the left and right rear wheels 3. ing.

  That is, as shown in FIG. 2, the sprung and lower acceleration sensor 10 (hereinafter referred to as acceleration sensor 10FL) on the left front wheel side and the sprung and lower acceleration sensor 10 (hereinafter referred to as acceleration sensor 10FR) on the right front wheel side. And a sprung and lower acceleration sensor 10 (hereinafter referred to as acceleration sensor 10R) on the rear wheel side. These acceleration sensors 10FL, 10FR, and 10R constitute a road surface state detector that detects the road surface state as upward and downward vibration acceleration while the vehicle is traveling, and output the detection signal to the controller 15 described later. .

  Further, the sprung speed on the vehicle body 1 side is detected as described later by detection signals from the acceleration sensors 10FL, 10FR, 10R. Among the acceleration sensors 10FL, 10FR, and 10R, for example, the acceleration sensors 10FL and 10FR are disposed in the vicinity of two damping force variable dampers 6 that are separated from each other in the horizontal direction of the vehicle body 1 among the plurality of damping force variable dampers 6 and 9. The first and second upper and lower speed detecting means for detecting the upper and lower speeds 1 are configured. Furthermore, the acceleration sensors 10FL, 10FR, 10R also constitute a horizontal axis rotational speed detecting means for detecting the roll rate or pitch rate of the vehicle body 1 as the horizontal axis rotational speed.

  Reference numeral 11 denotes a throttle sensor for detecting the acceleration / deceleration state of the vehicle. The throttle sensor 11 detects the opening of a throttle valve (not shown) provided in the engine of the vehicle, and the detection signal is a controller described later. 15 is output. Since the opening degree of the throttle valve is increased or decreased according to the operation amount of the accelerator pedal, the detection signal of the throttle sensor 11 increases or decreases according to the accelerator operation amount, that is, the acceleration / deceleration state of the vehicle.

  Reference numeral 12 denotes a brake operation detector that detects the braking state of the vehicle. The brake operation detector 12 detects, for example, a depression amount of a brake pedal (not shown) of the vehicle, and sends a detection signal to a controller 15 described later. Output. Further, the brake operation detector 12 in this case also detects which of the left and right front wheels 2 and the left and right rear wheels 3 is performing a brake operation.

  Reference numeral 13 denotes a vehicle speed sensor. The vehicle speed sensor 13 detects the rotational speed of the front wheels 2, for example, and outputs the detected signal as a vehicle speed signal to a controller 15 described later.

  A steering angle sensor 14 detects a steering operation amount of the vehicle. The steering angle sensor 14 detects an operation amount of a steering handle (not shown) of the vehicle, for example, and outputs a detection signal to the controller 15 described later. . That is, rolling of the vehicle occurs due to left and right accelerations accompanying the steering operation.

  Reference numeral 15 denotes a controller as a control means constituted by a microcomputer or the like. As shown in FIG. 2, the controller 15 has an acceleration sensor 10FL, 10FR, 10R on the input side, a throttle sensor 11, a brake operation detector 12, a vehicle speed sensor. 13 and the steering angle sensor 14, etc., and connected to an actuator (not shown) of the damping force variable damper 6 on the left front wheel side and the right front wheel side, and the damping force variable damper 9 on the left rear wheel side and the right rear wheel side. Has been.

  The controller 15 has a storage unit 15A composed of a ROM, a RAM, a non-volatile memory, and the like. In the storage unit 15A, a program for control processing shown in FIGS. 3 and 4 and a roll state determination shown in FIG. Maps 16 and the like are stored. Then, the controller 15 computes a damping force command signal to be output to an actuator (not shown) of each damping force variable damper 6 and 9 as a current value in accordance with the damping force control processing of each wheel shown in FIG. Each of the damping force variable dampers 6 and 9 is controlled so that the generated damping force is continuously variable between hardware and software or in a plurality of stages according to the current value (damping force command signal) supplied to the actuator.

  The suspension control apparatus according to the present embodiment has the above-described configuration. Next, processing for variably controlling the damping force characteristics of the damping force variable dampers 6 and 9 by the controller 15 will be described.

  First, the controller 15 executes a damping force control process for each wheel as shown in FIG. 3 when the vehicle engine is started to start and run. That is, in step 1 in FIG. 3, controller initialization is performed, and in the next step 2, it is determined whether or not the control cycle has been reached. The process waits while determining “NO” in step 2, and proceeds to the next step 3 when determining “YES”.

  In this step 3, the damping force command signals according to the control calculation process in step 6 described later are individually applied to the left and right front wheel side damping force variable dampers 6 and the left and right rear wheel side damping force variable dampers 9. And each actuator is driven independently. In the next step 4, a command signal is output to actuators (ports) other than the dampers 6 and 9.

  In step 5, sensor values are input, and detection signals are read from the acceleration sensors 10FL, 10FR, 10R, the throttle sensor 11, the brake operation detector 12, the vehicle speed sensor 13, the steering angle sensor 14, and the like. Then, in the next step 6, a process for controlling and calculating a damping force command signal to be individually output to each damping force variable damper 6 and 9 is performed in accordance with a program shown in FIG. 4 described later.

  That is, in the control calculation process of FIG. 4, the sprung speed and the lower speed of each wheel are calculated in step 11. In this case, when the sprung and lower speeds on the left and right front wheels are taken as an example, the left front wheel side is obtained by integrating the left and right front sprung and lower accelerations by the acceleration sensors 10FL and 10FR. The sprung and lower speed (hereinafter referred to as the left sprung speed VFL) and the sprung and lower speed (hereinafter referred to as the right sprung speed VFR) on the right front wheel side can be calculated.

  In the next step 12, the roll speed Vr of the vehicle body 1 is calculated according to the following equation (1) by calculating the difference between the left sprung speed VFL and the right sprung speed VFR. Further, in step 13, it is determined whether the left spring top speed VFL and the right spring top speed VFR are in-phase rolls or reverse-phase rolls based on the roll state determination map 16 shown in FIG. That is, when both the left spring upper speed VFL and the right spring upper speed VFR are upward or both downward, it is determined that the rolls are in-phase. Further, when one of the left spring upper speed VFL and the right spring upper speed VFR is upward and the other is downward, it is determined that the roll is a reverse phase roll.

  In step 14, it is determined whether the left spring sprung speed VFL and the right spring sprung speed VFR are reversed-phase rolls. When “YES” is determined, the rolls are reversed-phase rolls, and the vehicle body 1 is vibrated by rolling. It can be determined that Therefore, in this case, the process proceeds to step 15 where the roll speed Vr according to the equation 1 is multiplied by a gain of a predetermined value, and a roll FB control amount (that is, roll feedback control amount) corresponding to this is set. .

  In the next step 16, the damping coefficient of each wheel is set according to the roll FB control amount at this time. That is, for the damping force variable dampers 6 on the left front wheel side and the right front wheel side, the damping force characteristic is controlled so that the expansion side has a hard characteristic on the one hand and the contraction side has a hard characteristic on the other hand. Outputs a damping force command signal. Then, the process returns at step 17 thereafter.

  On the other hand, when it is determined as “NO” in step 14, the left sprung speed VFL and the right sprung speed VFR are in the same phase roll, so that only one of the left and right front wheels 2 gets over the step on the road surface. (For example, when roll resonance occurs at a frequency of about 2 to 3 Hz).

  Therefore, in the next step 18, the wheel side having the higher sprung speed among the left and right front wheels 2 is determined. For example, when the left front wheel 2 is used as a reference, it is determined whether or not the sprung speed on the left front wheel side is higher than the right front wheel 2 serving as the reverse wheel. Then, it can be determined that the wheel having the higher sprung speed is over the step of only one wheel and the vehicle is not over the step on the side of the slower wheel.

  If “YES” is determined in step 18, a gain of a predetermined value for the roll speed Vr according to the equation 1 is set on the wheel side with the higher sprung speed (that is, on the wheel side overstepping the step). And a roll FB control amount corresponding to this is set.

  If “NO” is determined in step 18, the roll FB control amount is not set on the side of the slower wheel (that is, the wheel that has not been stepped over), for example, the damping on the wheel side. Control is performed so that the force characteristic is maintained at the previous damping force command signal.

  In step 16, the damping coefficient of the damping force variable damper 6 is set according to the roll FB control amount on the wheel side where the sprung speed is faster due to overcoming the step, and the wheel having the slower sprung speed without stepping over the step is set. On the side, roll feedback control is canceled and damping force control similar to the previous control is continued. Thereafter, the process returns at step 17.

  Thus, according to the first embodiment, when the left sprung speed VFL and the right sprung speed VFR are determined to be in phase, on the wheel side having the higher sprung speed, the step over the step of only one wheel is overcome. When it is determined that it is performed, the roll speed Vr according to the equation 1 is multiplied by a predetermined gain, and the roll FB control amount corresponding to this is set, thereby switching the damping force characteristic to the hardware side.

  On the other hand, the wheel having the slower sprung speed is determined not to step over the step and the roll FB control amount is not set, and the damping force characteristic is not changed to the hard side, and the soft characteristic is maintained. That is, on the side of the wheel that is not overcoming the step, control is performed so that the damping force characteristic of the damping force variable damper 6 is maintained at the previous damping force command signal.

  As a result, the damping force characteristic can be properly controlled even when the step is over only one wheel, and the vehicle body 1 that is the upper side of the spring can be stopped well when the step is over only one wheel. Comfort can be improved.

  In the first embodiment, as the characteristic lines 24, 27, 30, 33, and 36 indicated by alternate long and short dash lines in FIG. A simulation result when only the left front wheel 2 side of the right front wheel 2 gets over the step can be obtained, and a damping effect can be exhibited.

  Next, FIGS. 6 to 8 show a second embodiment of the present invention. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. However, the feature of the second embodiment is that the damping force characteristic of the damping force variable damper 6 on the upper side of the left and right front wheels 2 above the spring and on the side of the wheel having the larger downward speed is higher. Therefore, the control is variably controlled in proportion to the downward speed.

  Here, FIG. 7 shows a process for controlling and calculating the damping force command signal to be individually output to each damping force variable damper 6 and 9, for example, a concrete example of the damping force control calculation process in step 6 of FIG. It is. In this case, the process from step 21 to step 28 in FIG. 7 is performed similarly to the process from step 11 to step 18 shown in FIG. 4 of the first embodiment described above.

  However, if “YES” is determined in the step 28, the roll FB gain is calculated in the next step 29 according to the characteristic line 21 shown in FIG. That is, the characteristic line 21 shown in FIG. 6 shows the characteristic of increasing or decreasing the roll FB gain in proportion to the upper and lower speeds on the spring, which is determined based on experimental data and the like. Accordingly, the roll FB gain is set to a small gain when the upper and lower speeds on the spring are small and slow, and is gradually set to a larger gain as the upper and lower speeds on the spring are increased.

  In the next step 30, the roll FB gain obtained in step 29 is multiplied by the roll speed Vr obtained by the above equation 1, and the roll FB control amount corresponding to this is set. Further, when “NO” is determined in step 28, the roll FB control amount is not set on the side of the slower wheel (that is, the wheel that has not been stepped over), which has a low sprung speed. Control is performed so that the damping force characteristic is maintained at the previous damping force command signal.

  In step 26, the damping coefficient of the damping force variable damper 6 is set according to the roll FB control amount on the side of the wheel having a higher sprung speed due to overcoming the step, and the wheel having the lower sprung speed without stepping over the step is set. On the side, roll feedback control is canceled and damping force control similar to the previous control is continued. Thereafter, the process returns at step 27.

  Thus, also in the second embodiment configured as described above, similarly to the above-described first embodiment, it is possible to satisfactorily stop the vehicle body 1 that is the upper side of the spring when stepping over only one wheel. The ride comfort of the vehicle can be improved. However, in the second embodiment, the roll FB gain is calculated as a gain proportional to the upward and downward speeds according to the characteristic line 21 shown in FIG. It is configured to do.

  As a result, the roll FB control amount is based on the gain that increases or decreases in proportion to the upward and downward speeds on the wheel side with the higher sprung and downward speeds (that is, on the wheel side where the step is overtaken). The damping force characteristic of the corresponding damping force variable damper 6 can be variably controlled according to the sprung speed. As a result, it is possible to improve the vibration damping performance when climbing over a step of only one wheel, and to reduce the left and right acceleration and roll rate of the vehicle.

  Here, the characteristic line shown in FIG. 8 shows the simulation result when only the left front wheel 2 side of the left and right front wheels 2 gets over the step while the vehicle is traveling on a rough road. . When traveling on rough roads, both the left and right front wheel side damping force variable dampers 6 are set to soft damping force characteristics.

  For this reason, the damping force variable damper 6 on the right front wheel side indicated as “FR” has the target damping force according to the second embodiment set to substantially zero as indicated by the characteristic line 22 indicated by the solid line in FIG. . That is, when overcoming the step on the left front wheel side, the target damping force on the right front wheel (FR) side is held at the previous value.

  On the other hand, in the case of the conventional technique, as shown by the characteristic line 23 shown by the dotted line, the right front wheel (after 2.0 to 2.3 seconds before and after, for example, is affected by stepping over the step on the left front wheel side. The target damping force on the FR) side has peaked rises on the minus side and the plus side. That is, in the case of the prior art (for example, refer to Patent Document 1), even when the step on the left front wheel side is overcome, the command signal obtained by multiplying the roll rate by the gain is output so that the characteristics are opposite in phase on the left and right. The target damping force is also set to be hard on the right front wheel side indicated as “FR”.

  A characteristic line 24 indicated by an alternate long and short dash line indicates the characteristic of the target damping force according to the first embodiment. Also in this case, when the step on the left front wheel side is overcome, the target damping force on the right front wheel (FR) side is held at the previous value, so that the right side is almost the same as the characteristic line 22 according to the second embodiment shown by the solid line. The target damping force on the front wheel (FR) side is set to almost zero.

  A characteristic line 25 indicated by a solid line as “current value FR” in FIG. 8 indicates the current value of the damping force command signal on the right front wheel side according to the second embodiment. Since the command signal on the right front wheel (FR) side is held at the previous value, it is set to a substantially constant current value. However, the characteristic line 26 indicated by a dotted line according to the prior art has a peak-like rise like the characteristic line 23 of the target damping force. A characteristic line 27 indicated by a one-dot chain line indicates the characteristic of the current value of the command signal according to the first embodiment.

  A characteristic line 28 indicated by a solid line as “sprung acceleration FR” in FIG. 8 indicates a detection signal of the sprung on the right front wheel side and the bottom acceleration sensor 10FR (see FIG. 2). A wave-like vibration is generated below. However, in the second embodiment, when the step on the left front wheel side is overcome, the damping force command signal on the right front wheel side is held at the previous value. Can be suppressed.

  On the other hand, the characteristic line 29 of the prior art indicated by the dotted line shows the influence of the road surface directly on the spring in order to switch the damping force command signal on the right front wheel side to a hard characteristic when overcoming the step on the left front wheel side, The amplitude of vibration is large. It should be noted that the characteristic line 30 according to the first embodiment indicated by a one-dot chain line has a vibration amplitude suppressed to be small in the same manner as the characteristic line 28 according to the second embodiment indicated by a solid line.

  A characteristic line 31 indicated by a solid line as “roll rate” represents the characteristic of the roll rate in the second embodiment, a characteristic line 32 indicated by a dotted line represents a conventional technique, and a characteristic line 33 indicated by a one-dot chain line represents a first characteristic line 33. The characteristic of the roll rate by embodiment is represented. A characteristic line 34 indicated by a solid line as “left and right acceleration” represents a characteristic of acceleration in the left and right directions in the second embodiment, a characteristic line 35 indicated by a dotted line represents a conventional technique, and a characteristic indicated by a one-dot chain line. A line 36 represents the left and right acceleration characteristics according to the first embodiment.

  Even in this case, the “roll rate” and “left and right acceleration” at the time of overcoming the step on the left front wheel side are the largest in the prior art (characteristic lines 32 and 35 shown by dotted lines), and this is the case in the second embodiment. Thus, it can be seen that the characteristic lines 31 and 34 indicated by the solid lines are kept small. In the case of the characteristic lines 33 and 36 (first embodiment) indicated by alternate long and short dash lines, the vibration damping effect is slightly reduced as compared with the characteristic lines 31 and 34 (second embodiment) indicated by solid lines. Yes.

  That is, in the second embodiment, the roll FB control amount is set in proportion to the upward and downward speeds on the wheel side where the step is overtaken, and the damping force characteristic of the corresponding damping force variable damper 6 is sprung. Since it is configured to be variably controlled in accordance with the speed, it is possible to improve the vibration damping performance when climbing over a step of only one wheel, compared to the first embodiment, the vehicle's left and right acceleration, Roll rate can also be reduced.

  In the first embodiment, the process of steps 13 and 14 shown in FIG. 4 is a specific example of the phase determining means, which is a constituent of the present invention, and the process of step 20 is a specific example of the damping force characteristic maintaining means. An example is shown. In the second embodiment, the processing of steps 23 and 24 shown in FIG. 7 shows a specific example of the phase determination means, and the processing of step 31 shows a specific example of the damping force characteristic maintaining means.

  Further, in the first embodiment, the upper and lower speeds are detected using the left front wheel side acceleration sensor 10FL and the right front wheel side acceleration sensor 10FR, and the roll of the vehicle body 1 is detected from the difference between the two speeds. The case where so-called roll control is performed by calculating the speed has been described as an example. However, the present invention is not limited to this. For example, the upper and lower speeds are detected using one of the front wheel side acceleration sensors 10FL and 10FR and the rear wheel side acceleration sensor 10R, and both of them are detected. By calculating the pitch speed of the vehicle body 1 from the speed difference, it may be determined whether the pitch is the in-phase pitch or the reverse-phase pitch, and the pitch control based on this is performed. This point is the same as in the second embodiment.

  In each of the above-described embodiments, the case where the upward and downward speeds of the spring are obtained by calculation from the detection signals of the upward and downward acceleration sensors 10 has been described as an example. However, the present invention is not limited to this, and for example, a configuration may be employed in which the upward and downward speeds on the spring are obtained by calculation using a signal from a vehicle height sensor that detects the height of the vehicle body 1.

  Further, in each of the above embodiments, the case where the rear wheel side acceleration sensor 10R is provided at the intermediate position between the left and right rear wheels has been described as an example. However, the present invention is not limited to this. For example, a sprung and lower acceleration sensor may be provided on the left rear wheel side, and a sprung and lower acceleration sensor may be provided on the right rear wheel side.

  Next, the invention included in the above embodiment will be described. That is, according to the present invention, the controller determines the damping force characteristic of the damping force adjustment type shock absorber with the larger upper and lower speeds among the two locations when the phase determining means determines that the phase is the same. Therefore, the control is variably controlled in proportion to the downward speed.

  As a result, it is determined that only one wheel has been stepped over, and the damping force characteristic of the shock absorber is maintained on the soft side without changing the damping force characteristic on the side of the wheel having the slower sprung speed. On the wheel side with the higher sprung speed, the damping force characteristics of the shock absorber can be variably controlled in proportion to the upper and lower speeds on the spring, and the vibration control when overcoming the step difference of only one wheel is possible. Can increase the sex. As a result, it is possible to more effectively control the damping force characteristics when climbing over the step of only one wheel, and it is possible to satisfactorily stop the vehicle body swinging on the upper side of the spring when climbing over the step of only one wheel. Comfort can be improved.

DESCRIPTION OF SYMBOLS 1 Car body 2 Front wheel 3 Rear wheel 4,7 Suspension device 5,8 Spring 6,9 Damping force variable damper (damping force adjustment type shock absorber)
10 Spring upper and lower acceleration sensors (horizontal axis rotation speed detection means, upper and lower speed detection means)
11 Throttle sensor 12 Brake operation detector 13 Vehicle speed sensor 14 Steering angle sensor 15 Controller (control means)

Claims (2)

A plurality of damping force adjusting type shock absorbers that are provided between the vehicle body and the plurality of wheels, respectively, and the damping force characteristics are variably adjusted;
A horizontal axis rotational speed detecting means provided on the vehicle body side for detecting a roll rate or pitch rate of the vehicle body as a horizontal axis rotational speed;
A controller for variably controlling the damping force characteristic of each damping force adjusting shock absorber according to the horizontal axis rotation speed,
The horizontal axis rotational speed detection means is configured to detect an upward and downward speed of the vehicle body in the vicinity of two damping force adjustable shock absorbers spaced apart from each other in the horizontal direction of the vehicle body among the plurality of damping force adjustable shock absorbers. Comprising first and second upper and lower speed detecting means for detecting,
The controller is
Phase determining means for determining whether or not the two upper and lower speeds detected by the first and second upper and lower speed detecting means are in phase;
A damping force characteristic maintaining means for maintaining the damping force characteristic of the damping force adjusting type shock absorber having the smaller upward speed when the phase determining means determines that the phase is the same phase. A suspension control apparatus characterized by the above.   When the controller determines that the phase is in phase by the phase determination means, the damping force characteristic of the damping force adjusting shock absorber having the larger upper and lower speeds out of the two locations is proportional to the upper and lower speeds. The suspension control device according to claim 1, wherein the suspension control device is configured to be variably controlled.

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