JP5093507B2 - Suspension control device - Google Patents

Description

  The present invention relates to a suspension control device used for a vehicle such as an automobile.

As an example of a conventional suspension control device, there is a suspension control device in which suspension characteristics are softened to improve riding comfort when passing through a step (see Patent Document 1).
JP 2007-127149 A

  By the way, on an asphalt pavement, asphalt may be peeled off and a hole called a pothole having a depth of about 10 cm or more may be formed on the surface. And when driving | running | working the road surface in which the pothole was formed, it is desired to ensure favorable driving | running | working. However, in a vehicle equipped with the above-described suspension control device of the prior art, when passing through the pothole formed on the road, the suspension characteristics are controlled so that the suspension characteristics are soft. There is a risk of impact and failure, and the above situation (running well on a road surface with potholes) is not adequately met and there is a need for improvement. there were. In addition, a conveyor that does not have a damping force adjustment function requires a high damping force to run through the pothole, and the ride quality deteriorates on other road surfaces.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a suspension control device capable of smoothly traveling on a road surface on which a pothole is formed.

  The present invention relates to a suspension control device for adjusting the damping force of a damping force adjusting type shock absorber used in a vehicle, a wheel load calculating means for obtaining a wheel load acting on a wheel, and a calculation obtained by the wheel load calculating means. Pothole judging means for judging whether or not the road surface during traveling of the vehicle is a pothole using a wheel load, and the pothole judging means is such that the road surface during traveling of the vehicle is a pothole. If it is determined, the damping force on the extension side of the damping force adjusting type shock absorber is made hard.

  ADVANTAGE OF THE INVENTION According to this invention, the smooth driving | running | working of the road surface in which the pothole was formed can be aimed at.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a diagram schematically showing an automobile 1 in which a suspension control device according to a first embodiment of the present invention is employed. FIG. 2 is a block diagram showing a configuration of the controller of FIG.
FIG. 3 is a diagram showing a ¼ vehicle body model in which the vertical vibration of the vehicle body is modeled with two degrees of freedom. FIG. 4 is a diagram schematically showing a relationship between forces applied to the vehicle body during acceleration / deceleration of the automobile shown in FIG. FIG. 5 is a diagram schematically showing a relationship between forces applied to the vehicle body during the turning of the automobile shown in FIG. FIG. 6 is a diagram schematically showing the relationship between forces applied to the vehicle body at the front axle position of the automobile shown in FIG. FIG. 7 is a diagram showing a wheel load estimated to be obtained when traveling on a road surface including a pothole in comparison with an actual value obtained by a corresponding simulation. FIG. 8 is a block diagram for explaining the function of the front and rear wheel delay time calculation unit of FIG. FIG. 9 is a flowchart showing the processing contents of the pothole determination unit in FIG. FIG. 10 is a block showing the processing contents of the control command calculation unit of FIG. FIG. 11 is a diagram illustrating a result of verifying the control effect of the first embodiment by simulation. FIG. 12 is a diagram showing a pothole simulated by the simulation of FIG.

1 and 2, each wheel [front left and right wheels 3FL and 3FR, rear left and right wheels 3RL and 3RR] of an automobile 2 on which the suspension control device 1 according to the first embodiment of the present invention is mounted. As appropriate, the wheels 3 are collectively referred to. ] Is a variable damping force type shock absorber (hereinafter also referred to simply as a shock absorber) 4FL, 4FR, 4RL, 4RR (hereinafter, collectively referred to as shock absorber 4 as appropriate), which is an example of a damping force adjusting type shock absorber. . ] Is attached.
A spring 5 is attached to the outer periphery of the shock absorber 4. The shock absorber 4 and the spring 5 are interposed between the vehicle body 6 and each wheel 3 and have a function of damping the vertical movement of each wheel 3.

  The vehicle body 6 is mounted with sprung acceleration sensors 7FL, 7FR, 7RR for detecting vertical acceleration (sprung vertical motion) acting on the vehicle body 6 corresponding to the front left and right wheels 3FL, 3FR and the rear right wheel 3RR. ing. The vehicle body 6 further includes longitudinal acceleration sensors 8 a and 8 b (generically designated by reference numeral 8 as appropriate) for detecting longitudinal and lateral accelerations acting on the vehicle body 6, a lateral acceleration sensor 9, and travel of the automobile 2. A vehicle speed sensor 11 for detecting the speed is attached. Corresponding to the front left and right wheels 3FL and 3FR, the front left and right wheels 3FL and 3FR (unsprung) have unsprung acceleration sensors 12FL and 12FR (which detect a vertical acceleration (unsprung vertical acceleration) acting on the portion). As appropriate, it is generally designated by reference numeral 12). In this embodiment, the case where the unsprung acceleration sensors 12FL and 12FR are attached to the front left and right wheels 3FL and 3FR is taken as an example, but the unsprung acceleration sensors 12FL and 12FR may be provided in other unsprung portions other than the wheels.

  A controller (control means) 13 is connected to the sprung acceleration sensors 7FL, 7FR, 7RR, longitudinal acceleration, lateral acceleration sensors 8, 9, vehicle speed sensor 11, and unsprung acceleration sensors 12FL, 12FR. The controller 13 receives the input of information from each connection member, estimates the wheel load of the front two wheels (front left and right wheels 3FL, 3FR) based on a calculation process described later, and based on the calculation results, A control command value (damping force command value) is calculated, and the shock absorber 4 is controlled.

As shown in FIG. 2, the controller 13 includes a front wheel load estimating unit (wheel load calculating unit, wheel load combining unit) 15, a pothole determining unit (pothole determining unit) 16, and a front and rear wheel delay time calculating unit 17. And a control command calculation unit 20.
In the front wheel load estimation unit 15, the sprung acceleration from the sprung acceleration sensors 7FL, 7FR, 7RR, the unsprung acceleration from the unsprung acceleration sensors 12FL, 12FR, the longitudinal acceleration from the longitudinal acceleration sensors 8a, 8b, and the lateral acceleration sensor The front wheel load is estimated using the lateral acceleration from 9. The pothole determination unit 16 determines whether or not it is a pothole from the estimated wheel load value, and outputs the determination result to the control command calculation unit 20. The front and rear wheel delay time calculation unit 17 calculates the front and rear wheel delay time using the vehicle speed (v) and the wheel base (L). The control command calculation unit 20 inputs the front and rear wheel delay times calculated by the pothole determination unit 16 and the front and rear wheel delay time calculation unit 17 and performs calculation processing for calculating a command value to be output to the damping force adjustment type shock absorber 4. Go to find the command value.

Next, the front wheel load estimating unit 15, the pothole determining unit 16, the front and rear wheel delay time calculating unit 17, and the control command calculating unit 20 will be described in detail.
The front wheel load estimating unit 15 estimates the wheel load as described above. First, the estimation principle of the wheel load will be described.
When the vertical vibration of the vehicle body 6 is modeled with two degrees of freedom, it is as shown in FIG. Here, the mass of the vehicle body 6 per wheel is m _b , the mass of the tire is m _t , the absolute vertical displacement of the vehicle body 6 is Z _b , the absolute vertical displacement of the tire is Z _t , and the absolute vertical displacement of the road surface is Z ₀ , The suspension spring constant is k _s , the damping coefficient is c _s , the tire spring constant is k _t , and the external force acting on the vehicle body 6 is f.
From this, the equation of motion of this system is as follows.

ここで輪荷重の変動分ΔＦ_zは、タイヤの反力となるので
ΔＦ_z＝−ｋ_t（Ｚ_t−Ｚ₀） （３）
となる。よって、 （１）、（２）式より、次式（４）の

となり、ばね上加速度

とばね下加速度

および外力ｆから輪荷重の変動分（輪荷重変動量）を計算することができる。また外力ｆは、旋回時や加減速時に発生する荷重移動量と考えれば、外力ｆは加速度センサで検出した前後・横加速度ａ_x、ａ_yより以下〔後述する式（１２）参照〕のように計算できる。図４に加減速中の車体６にかかる力を示す。図４において、車体６に前後加速度ａ_xが作用したときの荷重移動量ΔＦ_zxは、力とモーメントの釣合いより、
ΔＦ_zx＝−ｍ_sａ_xｈ_g／（２Ｌ） （５）
ただし、ｍ_s：車体６質量
となる。ここでｈ_gは重心点（車体６の重心点を指す。当該重心を以下、重心６Ｃという。）の高さ、Ｌはホイールベースを示す。これより加速時(ａ_x＞0)のとき前輪（３ＦＬ，３ＦＲ）の輪荷重は減少し、反対に後輪は増加するので、前輪（３ＦＬ，３ＦＲ）の荷重移動分（前後方向の加速度から得られる輪荷重移動量）をΔＦ_zxf、後輪（３ＲＬ，３ＲＲ）の荷重移動分（前後方向の加速度から得られる輪荷重移動量）をΔＦ_zxrとすると、これらは夫々、次の式（６）、（７）に示すようになる。
ΔＦ_zxf＝−ｍ_sａ_xｈ_g／（２Ｌ） （６）
ΔＦ_zxr＝−ｍ_sａ_xｈ_g／（２Ｌ） （７）

Here variation [Delta] F _z of the wheel load, since the reaction force of the tire _{ΔF z = -k t (Z t} -Z 0) (3)
It becomes. Therefore, from the equations (1) and (2), the following equation (4)

And sprung acceleration

And unsprung acceleration

The wheel load fluctuation amount (wheel load fluctuation amount) can be calculated from the external force f. If the external force f is considered to be the amount of load movement that occurs during turning or acceleration / deceleration, the external force f is determined from the longitudinal and lateral accelerations a _x and a _y detected by the acceleration sensor as shown below (see equation (12) below). Can be calculated. FIG. 4 shows the force applied to the vehicle body 6 during acceleration / deceleration. 4, the load shift amount [Delta] F _zx when acceleration a _x acts longitudinal to the vehicle body 6, from the balance of forces and moments,
_{ΔF zx = -m s a x h} g / (2L) (5)
However, m _{s is} 6 masses of the vehicle body. Here, h _g indicates the height of the center of gravity (refers to the center of gravity of the vehicle body 6. The center of gravity is hereinafter referred to as the center of gravity 6C), and L indicates the wheel base. As a result, the wheel load on the front wheels (3FL, 3FR) decreases and the rear wheel increases on acceleration (a _x > 0), so the load shift of the front wheels (3FL, 3FR) (according to the longitudinal acceleration) _Assuming that the obtained wheel load movement amount is ΔF _zxf and the load movement amount of the rear wheels (3RL, 3RR) (wheel load movement amount obtained from the acceleration in the front-rear direction) is ΔF _zxr , these are respectively _expressed by the following formulas (6 ), As shown in (7).
_{ΔF zxf = -m s a x h} g / (2L) (6)
_{ΔF zxr = -m s a x h} g / (2L) (7)

Next, the force applied to the vehicle body 6 at the time of turning is shown in FIG. Here, the front wheel roll rigidity Gf, the rear wheel roll rigidity Gr, the distance hc from the roll axis (Roll Axis) to the center of gravity 6C, the roll axis heights at the front and rear wheels are hf and hr, and the treads at the front and rear wheels [front side 2 The width between the wheels and the width between the two rear wheels] is L _wf and L _wr , respectively. If the lateral acceleration is a _y , the inertial force acting on the vehicle body 6 is m _s a _y .

FIG. 6 shows the balance in moment at the front axle position. In FIG. 6, the following equations hold when the distance from the front wheel axis to the center of gravity 6C and the distance from the rear wheel axis to the center of gravity 6C are Lf and Lr, respectively, from the balance of moments at the front axle position.
front wheel:
_{[G f / (G f +} G r)] m s a y h c - (L r / L) m s a y h f + ΔF zyf L wf = 0 (8)
The following equation holds true for the rear wheels as well.
Rear wheel:
_{[G r / (G f +} G r)] m s a y h c - (L f / L) m s a y h r + ΔF zyr L wr = 0 (9)
Here, ΔF _zyf and ΔF _zyr are the left and right load movement amounts on the front and rear wheels, respectively. From these equations (8) and (9),
_{ΔF zyf = (m s a y} / L wf) _{[[G f / (G f +} G r)] h c + (L r / L) h f ] = 0
(10)
_{ΔF zyr = (m s a y} / L wr) _{[[G r / (G f +} G r)] h c + (L r / L) h r ] = 0
(11)
It becomes. Here, when turning right (a _y > 0), the wheel load on the right side decreases and the wheel load on the left side increases.

  As for the external force f described above, as shown by the following equation (12), the sum or difference of the equations (5), (6) and (9), (10), that is, “the right side of (5)” And “Right side of (6)” + “Sum or difference of either one of“ Right side of (9) ”and“ Right side of (10) ”.

以上より、減速、右旋回時のとき各輪の輪荷重Ｆ_zは、各センサから検出したばね上加速度、ばね下加速度、前後加速度、横加速度を用いて式（１３）〜（１６）のように推定することができる。式（１３）〜（１６）でＧは重力加速度である。

ここで、ばね上、ばね下質量を前後輪で区別するため、前後輪それぞれのばね上質量をｍ_{b Fr}、ｍ_{b Rr}、ばね下質量をｍ_{t Fr}、ｍ_{t Rr}とした。このようにして推定した輪荷重推定値をポットホール判断部１６に出力する。

From the above, the wheel load F _z of each wheel at the time of deceleration and turning right is expressed by the equations (13) to (16) using the sprung acceleration, unsprung acceleration, longitudinal acceleration, and lateral acceleration detected from each sensor. Can be estimated as follows. In equations (13) to (16), G is the gravitational acceleration.

Here, in order to distinguish the sprung mass and unsprung mass between the front and rear wheels, the sprung mass of each of the front and rear wheels is _{expressed as Fr} , m _{b Rr} , unsprung mass m _{t Fr} , m _{t Rr} . The estimated wheel load estimated in this way is output to the pothole determining unit 16.

  In FIG. 7, using the logic of the front wheel load estimation unit 15 that executes the above-described processing, a simulation result when the automobile 2 passes through the pothole is shown as an estimated value by a solid line, and the behavior of the automobile 2 is simulated. For this purpose, the result of a similar simulation using software called so-called “cursim” is shown by a dotted line as an actual value. According to the front wheel load estimating unit 15 of the present embodiment, it can be seen that the wheel load can be estimated (calculated) satisfactorily as can be seen by comparing the estimated value with the actual value in FIG.

  Next, the front and rear wheel delay time calculation unit 17 will be described with reference to FIG. The front and rear wheel delay time calculation unit 17 calculates the vehicle speed and the wheel base determined by the specifications of the automobile 2, and calculates the wheel base by dividing it by the vehicle speed as shown in FIG.

  Next, the pothole determination unit 16 will be described. The pothole determination unit 16 determines whether or not the pothole is based on the estimated wheel load value. When passing through the pothole, the judgment is made by utilizing the fact that the wheel load is suddenly lost and the wheel load becomes zero. As shown in FIG. 9, the pothole determining unit 16 performs a calculation process based on loop control. The details of this calculation will be described below.

Pothole determination unit 16, as shown in FIG. 9, first, obtains the wheel load estimated value F _z and wheel load change [Delta] F _z, and calculates the time differential value dΔF _z (step S1). Next, it is determined whether the wheel load F _z is smaller than the threshold and whether the change rate of the wheel load fluctuation is smaller than the threshold (step S2). If it is determined in step S2 that the two conditions are satisfied, that is, if YES is determined, it is determined as a pothole, the pothole timer is cleared, and the pothole flag is set to 1 (step S3). In order to prevent malfunction as much as possible, the determination in step S2 is based on the determination based on the absolute value of the wheel load (the wheel load F _z ) and the change rate of the wheel load fluctuation. In addition, the wheel load estimated value considering the load movement is used to determine the absolute value (the absolute value of the wheel load), and the change rate (the rate of change of the wheel load fluctuation) is used to determine the change rate (the wheel load fluctuation only). In order to prevent misjudgment due to changes in

When the condition is not satisfied in step S2 (when it is determined NO), it is determined whether or not the pothole flag is 1 (step S4). If the condition is not satisfied in step S4 (that is, if it is determined as NO), the loop control is terminated without executing anything. If the condition is satisfied in step S4 (that is, if YES is determined), the process proceeds to determination (step S5) of whether the predetermined time has elapsed for the pothole timer. If it is determined in step S5 that the predetermined time has elapsed (that is, YES), the pothole flag is set to 0 and the timer is cleared (step S6). If it is determined in step S5 that the predetermined time has not elapsed (that is, if NO is determined), a timer is counted (step S7). In this way, it is determined whether or not it is a pothole (that is, whether or not the pothole flag is 1), and the pothole flag is set to be released when a predetermined time has elapsed after the pothole determination.
Although time management is used for canceling the pothole determination, it may be determined from an unsprung, sprung, or wheel load estimated value.

Next, the control command calculation unit 20 will be described. The control command calculation unit 20 calculates a control command value (control amount) based on the determination result in the pothole determination unit 16.
The control command calculation unit 20 calculates a control command value according to the determination result (pothole flag is 1 or 0) in the pothole determination unit 16. When the pothole flag is 1 and 0, the control command value (front wheel control command) that uses the damping force characteristics of the corresponding wheel (front wheel as a target) as hardware characteristics and software characteristics as control command values, respectively. Value) x is calculated.

When the determination result in the pothole determination unit 16 indicates that the pothole flag is 1, a control command value (front wheel control command value) having the damping force characteristic of the corresponding wheel (here, the front wheel is the target) as a hard characteristic ) Calculate x. In addition, when the determination result in the pothole determination unit 16 indicates that the pothole flag is 0, a control command value having soft characteristics as the damping force characteristic of the corresponding wheel (the front wheel is the target as described above) ( Front wheel control command value) x (scalar value) is calculated.
On the rear wheel side, the rear wheel control command value y (scalar value) is calculated with respect to the front wheel control command value x obtained from the determination result in the pothole determination unit 16 in consideration of the predetermined delay time τ. To do.
That is, the control command calculation unit 20 determines that the shock absorber 4 on the rear wheel side is a pothole, and then determines the system delay time from the front and rear wheel delay time (value calculated by the front and rear wheel delay time calculation unit 17). A control command value (rear wheel control command value) y (scalar value) having a damping force characteristic as a hard characteristic is calculated after a time obtained by subtracting the value, that is, “front and rear wheel delay time−system delay time” has elapsed. Here, the system delay time corresponds to a calculation time, an actuator response time, and the like.
The control command calculation unit 20 obtains a control command value (vector) by simultaneously processing the front wheel and rear wheel control command values x and y (scalar values) as vectors.
As described above, the rear wheel side shock absorber 4 can be made hard before reaching the pothole, so that the control effect can be maximized. The time for switching the shock absorber 4 on the rear wheel side to the hard characteristic immediately before reaching the pothole can shorten the time for making it hard, so that it is possible to prevent the deterioration of riding comfort due to the influence other than the pothole.

The present inventor has described the suspension control device 1 according to the above-described embodiment for the behavior during control during pothole travel, the conventional technology in which the control force is soft during pothole travel [control force software (SS) or control force soft as appropriate. It is called conventional technology. ] Conventional technology that does not have a damping force adjusting function [appropriately referred to as a convex technique or simply as a convex. ], The simulation of the command current for the front and rear wheels, the estimated wheel load, the unsprung acceleration on the front and rear wheels, and the unsprung acceleration was performed. As shown in FIG. 12, the simulation was performed such that the automobile 2 traveled at a vehicle speed of 60 km / h and passed through a road surface simulating a pothole having a depth of 100 mm and a length of 762 mm. The result shown in FIG. 11 was obtained by the simulation.

As shown in FIG. 11, according to the suspension control device 1 of the above embodiment, the damping performance of the rear wheel side unsprung acceleration and sprung acceleration is improved as compared with the conventional technique and the control force software conventional technique. The PP value is equal to or higher than that of the conveyor technology,
As for the unsprung acceleration and sprung acceleration on the front wheel side, the damping performance is equal to or higher than that of the convex technique, the PP value is equal to that of the convex technique, and the control force software is smaller and improved than the conventional technique. In other words, it was confirmed that the impact input can be reduced in the pothole, and the unsprung and unsprung vibrations can be reduced.

According to the present embodiment, when the pothole determination unit 16 determines that the road surface during travel of the automobile 2 is a pothole, the damping force on the expansion side of the shock absorber 4 is made hard, so when passing through the pothole, By avoiding the follow-up to the pothole, it is possible to smoothly shift to the road surface after passing through the pothole. Furthermore, the elongation displacement is suppressed, the impact in the latter half of passing through the pothole can be reduced, and the impact applied to the shock absorber 4 can be suppressed.
Also, by determining the pothole using the estimated wheel load as described above, it is possible to control the unsprung state before it vibrates, and the ride comfort can be reduced by reducing impact input and suppressing unsprung rampage. Can be improved.

  In the above embodiment, the front wheel load estimating unit 15 calculates the wheel load of the front two wheels by calculating the front wheel side spring top, front wheel side unsprung, front and rear, lateral acceleration sensors (7FL, 7FR, 12FL, 12FR, 8a, 8b). , 9) is based on the front-wheel-side spring, front-wheel-side unsprung, front-rear, and lateral acceleration, respectively. , 7FR, 12FL) may be configured to be performed based on the front wheel-side spring acceleration and the front wheel-side unsprung acceleration detected respectively.

In the above-described embodiment, the pothole determination unit 16 determines whether or not the road surface during travel of the automobile 2 is a pothole by comparing the calculated wheel load with a predetermined wheel load threshold value, and Although the case of performing based on the comparison result of the calculated wheel load reduction rate corresponding to the reduction rate of the calculated wheel load and a predetermined wheel load reduction rate threshold value is taken as an example, instead of this, the calculated wheel load and You may make it perform based on the comparison result with a predetermined wheel load threshold value. In addition, the determination process may be performed based on a comparison result between a calculated wheel load reduction rate corresponding to the calculated wheel load reduction rate and a predetermined wheel load reduction rate threshold value.
In addition, since the unsprung acceleration sensors 12FL and 12FR are provided only on the front wheel side to estimate the wheel load, the number of unsprung acceleration sensors can be reduced as compared with the case where the unsprung acceleration sensor is provided on the rear wheel side. Therefore, the cost can be reduced.

  In the above embodiment, the case where the front wheel load estimating unit 15 estimates the front wheel load is taken as an example, but instead of this, a wheel load sensor (wheel load calculating means) for detecting the wheel load may be provided. Good.

Next, a suspension control apparatus 1A according to a second embodiment of the present invention will be described with reference to FIGS.
The suspension control device 1A according to the second embodiment of the present invention has an acceleration sensor 7 as shown in FIGS. 1, 2, and 13 to 15, as compared with the suspension control device 1 according to the first embodiment. , 8, 9 and 12, load sensors (wheel load measuring devices) 22FL and 22FR are provided on the front two wheels (3FL and 3FR) to detect the wheel load of the front two wheels (3FL and 3FR), and The main difference is that the longitudinal acceleration sensors 8a and 8b and the lateral acceleration sensor 9 are eliminated, and that steps S1A and 2A instead of steps S1 and S2 are executed.
FIG. 14 shows an outline of processing performed in the controller 13A of the suspension control device 1A according to the second embodiment. The load sensors 22FL and 22FR detect the wheel loads of the two front wheels (3FL and 3FR) and output the values to the pothole determination unit 16A. The pothole determination unit 16A determines from the detected wheel load value whether or not the road surface when the vehicle 2 is traveling is a pothole, and outputs the determination result to the control command calculation unit 20. Thereafter, the control amount is calculated in the same manner as in the first embodiment, and is output to the damping force adjustable shock absorber 4.

Pothole determination section 16A, as shown in FIG. 15, first load sensors 22FL, obtains the wheel load F _z detected by 22FR, and calculates the time differential value (step S1A). Next, it is determined whether or not the wheel load F _z is smaller than the threshold and whether or not the wheel load change rate dF _z is smaller than the threshold (step S2A). If two conditions are satisfied (YES in step S2A) If it is determined), it is determined that the road surface during travel of the automobile 2 is a pothole, the pothole timer is cleared, and the pothole flag is set to 1 (step S3).

Here, in order to prevent malfunction as much as possible, the determination based on the wheel load absolute value and the determination based on the change rate of the wheel load fluctuation are used. If the condition is not met, it is determined whether the pothole flag is 1. If the conditions are not satisfied, the process ends without executing anything. When the condition is satisfied, the process proceeds to determination of whether the predetermined time has elapsed for the pothole timer. If the predetermined time has elapsed, the pothole flag is set to 0 and the timer is also cleared. If it has not elapsed, the timer is counted. In this way, it is determined whether or not it is a pothole, and the pothole flag is set to be canceled when a predetermined time has elapsed after the pothole determination. In addition, although time management was used for cancellation | release of pothole determination, you may determine from wheel load etc.
In the subsequent processing, as in the case of the first embodiment, the control command calculation unit 20 calculates the control amount and outputs the calculated control command value to the damping force variable shock absorber 4.

1 is a perspective view schematically showing an automobile 2 in which a suspension control device according to a first embodiment of the present invention is employed. It is a block diagram which shows the structure of the controller of FIG. It is a figure which shows the 1/4 vehicle body model which modeled the vertical vibration of the vehicle body in 2 degrees of freedom. It is a figure which shows typically the relationship of the force applied to a vehicle body during the acceleration / deceleration of the motor vehicle of FIG. It is a figure which shows typically the relationship of the force applied to the vehicle body 6 during turning of the motor vehicle of FIG. It is a figure which shows typically the relationship of the force concerning the vehicle body in the front axle position of the motor vehicle of FIG. It is a figure which shows the wheel load estimated to be obtained at the time of road surface including a pothole in contrast with the actual value obtained by a corresponding simulation. It is a block diagram for demonstrating the function of the front-and-rear wheel delay time calculation part of FIG. It is a flowchart which shows the processing content of the pothole judgment part of FIG. It is a block which shows the processing content of the control command calculating part of FIG. It is a figure which shows the result of having verified the control effect of 1st Embodiment by simulation. It is a figure which shows the pothole simulated by the simulation of FIG. It is a perspective view showing typically automobile 2 by which a suspension control device concerning a 2nd embodiment of the present invention was adopted. It is a block diagram which shows the structure of the controller of FIG. It is a flowchart which shows the processing content of the pothole judgment part of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Suspension control apparatus, 2 ... Automobile (vehicle), 3FL, 3FR (3) ... Front left-right wheel, 3RL, 3RR (3) ... Rear left-right wheel, 4FL, 4FR, 4RL, 4RR (4) ... Damping force variable type Shock absorber (damping force adjustable shock absorber), 7FL, 7FR, 7RR ... sprung acceleration sensor, 8 ... longitudinal acceleration sensor, 9 ... lateral acceleration sensor, 10 ..., 11 ..., 12FL, 12FR ... unsprung acceleration sensor, 13 ... Controller 15. Front wheel load estimation unit (wheel load calculation means, wheel load synthesis unit) 16. Pothole determination unit (pothole determination means).

Claims (11)

A suspension control device for adjusting the damping force of a damping force adjusting type shock absorber used in a vehicle,
A wheel load calculating means for determining a wheel load acting on the wheel;
Pothole judging means for judging whether or not the road surface during travel of the vehicle is a pothole using the calculated wheel load obtained by the wheel load calculating means,
A suspension control device characterized in that, when the pothole judging means judges that the road surface during travel of the vehicle is a pothole, the damping force on the extension side of the damping force adjusting type shock absorber is made hard.   2. The suspension control device according to claim 1, wherein the pothole determination unit performs the determination process based on a comparison result between the calculated wheel load and a predetermined wheel load threshold value. 3. apparatus.   2. The suspension control device according to claim 1, wherein the pothole determining means is based on a comparison result between a calculated wheel load reduction rate corresponding to the reduction rate of the calculated wheel load and a predetermined wheel load reduction rate threshold value. A suspension control device that performs the determination process.   2. The suspension control device according to claim 1, wherein the pothole determining means calculates a calculated wheel load corresponding to a comparison result between the calculated wheel load and a predetermined wheel load threshold value and a reduction rate of the calculated wheel load. 3. A suspension control device characterized in that the determination processing is performed based on a comparison result between a reduction rate and a predetermined wheel load reduction rate threshold value.   5. The suspension control device according to claim 1, wherein the wheel load calculating means calculates a front wheel side sprung acceleration sensor that detects a vertical acceleration on a front wheel spring and a spring acceleration below the front wheel. A front wheel side unsprung acceleration sensor for detecting, and calculating the wheel load of the front two wheels from the front wheel side sprung and front wheel side unsprung acceleration sensors respectively detected by the front wheel side unsprung acceleration sensor. Suspension control device characterized by this.   5. The suspension control device according to claim 1, wherein the wheel load calculating means calculates a front wheel side sprung acceleration sensor that detects a vertical acceleration on a front wheel spring and a spring acceleration below the front wheel. A front wheel side unsprung acceleration sensor for detecting, a longitudinal acceleration sensor for detecting longitudinal acceleration acting on the vehicle body, and a lateral acceleration sensor for detecting lateral acceleration acting on the vehicle body, wherein the front wheel side spring comprises A suspension control device that calculates wheel loads of the front two wheels from a front wheel side spring, front wheel side unsprung, front and rear, and lateral acceleration detected by an upper, front wheel unsprung, front and rear, and lateral acceleration sensors, respectively. A suspension control device for adjusting the damping force of a damping force adjusting type shock absorber used in a vehicle,
By synthesizing the wheel load fluctuation amount obtained from the vertical acceleration under the spring and unsprung of the vehicle and the load movement amount obtained from the longitudinal and lateral acceleration acting on the vehicle body, the wheel load acting on the wheel is obtained. , Wheel load calculating means having a wheel load combining unit to be calculated as a calculated wheel load;
Pothole judging means for judging whether or not the road surface during travel of the vehicle is a pothole based on the calculated wheel load;
The pothole judging means includes a comparison result between the calculated wheel load and a predetermined wheel load threshold value, a calculated wheel load reduction rate corresponding to a reduction rate of the calculated wheel load, and a predetermined wheel load reduction rate. It is configured to perform the determination process based on a comparison result with a threshold value,
The pothole determining means is configured to use the wheel load fluctuation amount for the comparison processing related to the wheel load reduction rate,
A suspension control device characterized in that, when the pothole determining means determines that the road surface during travel of the vehicle is a pothole, the damping force on the extension side of the damping force adjusting type shock absorber is made hard.   7. The suspension control device according to claim 5, wherein the front-wheel unsprung acceleration sensor is attached to the two front wheels.   5. The suspension control device according to claim 1, wherein the wheel load calculating means is a wheel load measuring device that measures a wheel load. 6.   The suspension control device according to claim 9, wherein the wheel load measuring device is attached to the front two wheels.   11. The suspension control device according to claim 1, wherein the rear wheel side damping force adjustment type shock absorber has a hard damping force of the front wheel side damping force adjustment type shock absorber, and then the vehicle speed and the wheel are adjusted. A suspension control device characterized in that it is made hard after a time considering a system delay time from a delay time calculated by a base.

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