JP2007245956A - Suspension control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the occurrence of the abutment of a bound stopper or a rebound stopper by a simple constitution even in the state that a vehicle height is deviated from a standard position during the adjustment of the vehicle height, and to enhance riding comfortability. <P>SOLUTION: This suspension control device is provided with suspensions 31-34 each having a vehicle height adjustment and attenuation force adjustment function of the vehicle; an exhaust valve V0, a compressor 30, valves V1-V4, vehicle height sensors 21-24 and suspension control actuators 11-14. when it is determined by a suspension control computer 3 that vehicle height adjustment is performed, the attenuation force is set larger than the attenuation force when the vehicle height adjustment is not performed. Further, when it is determined as a failure of a vehicle height adjustment system, the vehicle height adjustment is interrupted and it is switched to attenuation control (attenuation force is fixed to the maximum stage number) at a failure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a suspension control device, and more specifically, even when the vehicle height is deviated from a standard position during vehicle height adjustment, occurrence of hitting a bound stopper or a rebound stopper can be suppressed with a simple configuration. The present invention relates to a suspension control device that can improve riding comfort.

  A damping device (hydraulic cylinder) and an air spring are provided for each vehicle wheel, and the vehicle height is increased according to the running state of the vehicle, the number of passengers, and the loading capacity by supplying and discharging air (air) to and from the air spring. Various techniques for adjustment have been proposed (see, for example, Patent Document 1).

  In addition, as a related technology, if the vehicle height adjustment does not stop because the vehicle height does not reach the target even after the compressor has been operating for a predetermined time, it is determined that the vehicle height adjustment system is abnormal and A technique for warning has been proposed (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 7-237421 Japanese Examined Patent Publication No. 62-56803

  However, in the above prior art, if the number of passengers and load is large and the vehicle travels immediately after the engine is started, the vehicle height cannot be adjusted and the vehicle height remains low. There was a problem that the bounce stopper hit frequently and the ride comfort became uncomfortable.

  In addition, there is a problem that the vehicle height is high immediately after the passenger gets off the vehicle or immediately after the load is lowered and the vehicle height adjustment is finished, and the rebound stopper hits frequently and the same problem occurs. .

  Further, when adjusting the vehicle height using air in the air suspension, it takes time to adjust the vehicle height as compared with the hydraulic suspension. The size of the air compressor or air dryer that determines the vehicle height adjustment time and the use of the pressure accumulator are subject to restrictions on mounting in the vehicle, so install a large capacity object that can adjust the vehicle height in a short time. I can't. For this reason, it has been difficult to instantaneously adjust the vehicle height with an air compressor having a relatively small capacity.

  The present invention has been made in view of the above, and even when the vehicle height is shifted from the standard position during the vehicle height adjustment, the occurrence of hitting the bounce stopper or the rebound stopper is suppressed with a simple configuration. An object of the present invention is to provide a suspension control device that can improve the ride comfort.

  In addition, even if the vehicle height adjustment is not properly performed due to a failure of the suspension or the like, the present invention can suppress the occurrence of hitting the bound stopper or the rebound stopper by switching to the damping force control at the time of the failure. An object of the present invention is to provide a suspension control device that can be used.

  In order to solve the above-described problems and achieve the object, a suspension control apparatus according to a first aspect of the present invention includes vehicle height adjusting means for adjusting the vehicle height of the vehicle, and variable damping force for changing the damping force of the suspension. And a vehicle height adjustment state determination unit that determines whether or not the vehicle height is being adjusted, and when the vehicle height adjustment state determination unit determines that the vehicle height is being adjusted, the damping force is It is characterized by being set larger than the damping force when the vehicle height is not being adjusted.

  A suspension control apparatus according to a second aspect of the present invention is the suspension control device according to the first aspect, further comprising abnormality detection means for detecting an abnormality at the time of vehicle height adjustment of the vehicle height adjustment means. When an abnormality is detected, the damping force by the damping force varying means is set to be larger.

  According to a third aspect of the present invention, there is provided a suspension control device according to the second aspect of the invention, further comprising a time measuring means for detecting an elapsed time since the start of the vehicle height adjustment, which is detected by the time measuring means. When the elapsed time exceeds a predetermined value, the abnormality detection means detects an abnormality and sets the damping force by the damping force variable means to be larger.

  According to a fourth aspect of the present invention, there is provided a suspension control apparatus according to the second aspect, further comprising driving current measuring means for detecting a driving current value of the vehicle height adjusting means during vehicle height adjustment, wherein the driving When the driving current value detected by the current measuring unit exceeds a predetermined value, the abnormality detecting unit detects an abnormality and sets the damping force by the damping force varying unit to be larger. Is.

  According to the suspension control device of the present invention (Claim 1), even when the vehicle height is adjusted, the damping force is more than the damping force when the vehicle height is not being adjusted. Since it is set to be large, it is possible to suppress the occurrence of the bounce stopper or the rebound stopper with a simple configuration, and to improve the riding comfort.

  According to the suspension control device of the present invention (Claim 2), an abnormality (fault) at the time of vehicle height adjustment can be easily detected by the abnormality detection means, and the vehicle height adjustment is not properly performed due to the failure. By switching to damping force control at the time of failure (for example, fixing the damping force to the maximum number of stages), the occurrence of per bound stopper or rebound stopper can be suppressed.

  Further, according to the suspension control device of the present invention (Claim 3), it is possible to detect an abnormality at the time of adjusting the vehicle height based on the elapsed time detected by the time measuring means, and to easily switch to the damping force control at the time of failure. Can do.

  Further, according to the suspension control device of the present invention (Claim 4), an abnormality at the time of vehicle height adjustment can be detected based on the drive current value detected by the drive current measuring means, and the damping force control at the time of failure is easy. You can switch to

  Embodiments of a suspension control apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a perspective view showing an outline of a vehicle provided with a suspension control device according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a suspension control (vehicle height control) device. As shown in FIG. 1, the vehicle C including the suspension control device 1 has wheels disposed at four positions, front, rear, left, and right.

  Also, suspensions (vehicle height adjusting means, damping force variable means) for adjusting the vehicle height and adjusting the damping force are provided at positions corresponding to the respective wheels. In addition, a suspension control actuator (vehicle height adjusting means, hereinafter referred to as “SCA”) for adjusting the vehicle height by these suspensions is provided.

  That is, as these suspensions, the right front suspension 31 at a position corresponding to the right front wheel, the left front suspension 32 at a position corresponding to the left front wheel, the right rear suspension 33 at a position corresponding to the right rear wheel, and a position corresponding to the left rear wheel. A left rear suspension 34 is provided.

  The suspensions 31 to 34 are so-called air suspensions in which an air spring is configured by expansion / compression of compressed air in the air chamber. The suspensions 31 to 34 have a function of keeping the vehicle height constant regardless of changes in the number of passengers and the load capacity, and can adjust the vehicle height so as to correspond to the driving situation and road surface condition. It is configured.

  Further, as these SCA, the right front SCA 11 at a position corresponding to the right front wheel, the left front SCA 12 at a position corresponding to the left front wheel, the right rear SCA 13 at a position corresponding to the right rear wheel, and the left rear SCA 14 at a position corresponding to the left rear wheel. Are provided.

  The right front suspension 31 is connected to a right front valve (vehicle height adjusting means) V1 as a vehicle height adjusting valve for the right front wheel. The left front suspension 32 is connected to a left front valve (vehicle height adjusting means) V2 as a vehicle height adjusting valve for the left front wheel.

  The right rear suspension 33 is connected to a right rear valve (vehicle height adjusting means) V3 as a vehicle height adjusting valve for the right rear wheel. The left rear suspension 34 is connected to a left rear valve (vehicle height adjusting means) V4 as a vehicle height adjusting valve for the left rear wheel.

  Further, a compressor (vehicle height adjusting means) 30 having an exhaust valve (vehicle height adjusting means) V0 is connected to each of the suspensions 31 to 34. Then, air is supplied or discharged from the compressor 30 to the suspensions 31 to 34 via the valves (vehicle height adjusting means) V1 to V4, and the SCAs 11 to 14 are operated to adjust the heights of the wheels. Thus, the vehicle height of the wheel is adjusted, and the damping force of the suspension is adjusted.

  Furthermore, a vehicle height sensor (vehicle height adjusting means) for detecting the vehicle height is provided at a position corresponding to each wheel. That is, the right front vehicle height sensor 21 is located at the position corresponding to the right front wheel, the left front vehicle height sensor 22 is located at the position corresponding to the left front wheel, the right rear vehicle height sensor 23 is located at the position corresponding to the right rear wheel, and the position corresponding to the left rear wheel. The left rear vehicle height sensor 24 is provided respectively.

  The vehicle C is provided with a suspension control computer (vehicle height adjustment state determination means) 3 for controlling the SCAs 11 to 14. As shown in FIG. 2, the suspension control computer 3 is connected to the valves V1 to V4, the SCAs 11 to 14, the vehicle height sensors 21 to 24, the compressor 30, and the exhaust valve V0.

  The suspension control computer 3 receives predetermined signals output from the vehicle height sensors 21 to 24, vehicle speed signals from a vehicle speed sensor (not shown), and the like. The suspension control computer 3 calculates the vehicle height at the position corresponding to each wheel based on these signals, and outputs a control signal to each SCA 11 to 14 so as to obtain the calculated vehicle height.

  The suspension control computer 3 determines the operating state of the compressor 30 and the valves V0 to V4 and controls them to control the amount of air supplied to the suspensions 31 to 34.

  The suspension control computer 3 stores threshold values Δh1 and Δh2 for starting the vehicle height adjustment control, threshold values for determining a failure of the suspensions 31 to 34, and the like, which will be described later based on these threshold values and the like. Adjust the vehicle height. The suspension control computer 3 also includes a counter (time measuring means) for measuring the vehicle height adjustment time (elapsed time), and serves as an abnormality detection means for detecting an abnormality in the suspensions 31 to 34 and the like based on the vehicle height adjustment time. It functions.

  Note that the damping force of each of the suspensions 31 to 34 is adjusted in accordance with the traveling state of the vehicle C by the right front actuator 41, the left front actuator 42, the right rear actuator 43, and the left rear actuator 44, respectively, as shown in FIG. .

  These actuators 41 to 44 are controlled by an absorber control computer 40 based on output signals of a steering angle sensor 45, a stop lamp switch 46, a sprung acceleration sensor 47, and output signals S1 to S6 of a suspension control computer 3 described later. Is done.

  Here, FIG. 3 is a block diagram showing a suspension control (damping force control) device. Further, as shown in FIG. 6, the absorber control computer 40 stores in advance a damping force map used when switching the number of damping force steps.

  Next, the control operation will be described. In the control operation according to the present embodiment, the normal damping force control is interrupted simultaneously with the start of the vehicle height adjustment, and the control is switched to the damping force control at the time of vehicle height adjustment. In this damping force control, because the vehicle height is lower than or higher than the standard position, so-called per-bound stopper or rebound stopper is likely to occur. The number of steps is regulated. In addition to this control, the vehicle height adjustment time is monitored, and if it exceeds a certain time, it is judged that the vehicle height adjustment system has failed (failure), and the damping force control during the failure (the damping force is fixed at the maximum number of stages) ).

  Hereinafter, the vehicle height control by the suspension control computer 3 will be described based on FIG. 4 by taking the right front wheel as an example. Here, FIG. 4 is a flowchart showing the vehicle height control. As shown in FIG. 4, first, the current vehicle height HFR0 of the right front wheel is read by the right front vehicle height sensor 21 (step S100).

  Next, it is determined whether or not the difference between the target vehicle height HFRR of the right front wheel and the current vehicle height HFR0 is equal to or greater than a vehicle height adjustment start threshold value Δh1 (step S110). If the vehicle height adjustment start threshold value Δh1 or more (Yes at Step S110), it is determined whether the compressor 30 is OFF and the right front valve V1 is closed (Step S120).

  If the compressor 30 is OFF and the right front valve V1 is closed (Yes at Step S120), a vehicle height adjustment start signal S1 is output to adjust the insufficient vehicle height (Step S130). ), The compressor 30 is turned on, and the right front valve V1 is opened (step S140). Thereby, the vehicle height adjustment is started toward the target vehicle height HFRR.

  Then, after resetting the counter of the suspension control computer 3, the vehicle height adjustment time is measured (step S150), and the process returns to the start. The vehicle height adjustment start signal S1 in step S130 is input to A in a damping force control flowchart shown in FIG.

  On the other hand, if the determination in step S120 is negative, it is determined whether the vehicle height adjustment time T1 measured so far is equal to or greater than a failure determination threshold T10 (step S160). If the measured vehicle height adjustment time T1 is not longer than the failure determination threshold value T10 (No at step S160), the process returns to the start and the vehicle height adjustment is continued.

  If the vehicle height adjustment time T1 is equal to or greater than the failure determination threshold value T10 (Yes at Step S160), it is determined that the right front suspension 31 has failed (abnormal), and a vehicle height adjustment interruption signal S5 is output (Step S170). The control is interrupted (step S180). The vehicle height adjustment interruption signal S5 in step S170 is input to A in a damping force control flowchart shown in FIG.

  If the difference between the target vehicle height HFRR of the right front wheel and the current vehicle height HFR0 is not equal to or greater than the vehicle height adjustment start threshold value Δh1 (No in step S110), the compressor 30 is ON. In addition, it is determined whether or not the right front valve V1 is opened (step S190).

  If the determination in step S190 is affirmative, it can be determined that the target vehicle height has been reached, so a vehicle height adjustment end signal S3 is output (step S200), the right front valve V1 is closed, and the compressor 30 Is turned off (step S210), and the process returns to the start. Note that the vehicle height adjustment end signal S3 in step S200 is input to A of the damping force control flowchart shown in FIG.

  On the other hand, if the determination in step S190 is negative, it is determined whether the difference between the target vehicle height HFRR of the right front wheel and the current vehicle height HFR0 is equal to or less than a vehicle height adjustment start threshold −Δh2. (Step S220).

  If the vehicle height adjustment start threshold value −Δh2 or less (Yes at Step S220), it is determined whether or not the exhaust valve V0 and the right front valve V1 are closed (Step S230).

  If the determination in step S230 is affirmative, a vehicle height adjustment start signal S2 is output to reduce the current vehicle height that exceeds the target vehicle height (step S240), and the exhaust valve V0 and the right front valve V1 are turned off. The valve is opened (step S250), and the vehicle height adjustment time measurement counter is reset once and then started (step S260), and the process returns to the start. Note that the vehicle height adjustment start signal S2 in step S240 is input to A of the damping force control flowchart shown in FIG.

  If the determination in step S230 is negative, it is determined whether the vehicle height adjustment time T2 measured so far is equal to or greater than a failure determination threshold T20 (step S270). If the measured vehicle height adjustment time T2 is not equal to or greater than the failure determination threshold T20 (No at Step S270), the process returns to the start and continues the vehicle height adjustment.

  If the vehicle height adjustment time T2 is equal to or greater than the failure determination threshold T20 (Yes at Step S270), it is determined that the right front suspension 31 is out of order, and a vehicle height adjustment interruption signal S6 is output (Step S280). The process is interrupted (step S290). The vehicle height adjustment interruption signal S6 in step S280 is input to A in the damping force control flowchart shown in FIG.

  If the vehicle height adjustment start threshold value −Δh2 or less is not satisfied (No in step S220), it is determined that the current vehicle height has decreased to the target vehicle height, and the exhaust valve V0 and the right front valve V1 are then opened. It is determined whether or not (step S300).

  If the determination in step S300 is affirmative, it can be determined that the target vehicle height has been reached normally, so a vehicle height adjustment end signal S4 is output (step S310), and the exhaust valve V0 and the right front valve V1 are turned on. The valve is closed (step S320). Note that the vehicle height adjustment end signal S4 in step S310 is input to A of the damping force control flowchart shown in FIG.

  As described above, the vehicle height control or the like is executed for the right front wheel, but the left front wheel and the left and right rear wheels are also controlled in the same manner as described above.

  Next, the damping force control by the absorber control computer 40 will be described with reference to FIG. Here, FIG. 5 is a flowchart showing the damping force control. Damping force control is performed based on the output signals S1 to S6 from the vehicle height adjustment control described above. That is, control is performed in which the damping force is changed in accordance with the vehicle speed, giving priority to ride comfort at low speeds and giving priority to steering stability at high speeds. Hereinafter, it will be described in more detail with reference to FIG.

  As shown in FIG. 5, if the vehicle height adjustment interruption signal S5 or S6 output in the above-described vehicle height adjustment control is ON in step S400 (Yes in step S400), for example, the attenuation shown in FIG. The force map 3 is used (step S410), the number of steps is determined so that the damping force is maximized regardless of the read vehicle speed (step S420) (step S430), and the right front actuator 41 is driven so as to be this number of steps. (Step S440).

  On the other hand, if the vehicle height adjustment interruption signal S5 or S6 is not ON in step S400 (No in step S400), it is determined whether or not the vehicle height adjustment start signal S1 or S2 is ON (step S400). Step S450).

  If the vehicle height adjustment start signal S1 or S2 is ON (Yes at Step S450), the damping force map 2 shown in FIG. 6 is used (Step S460), and the number of steps according to the read vehicle speed (Step S420). Is determined (step S430), and the right front actuator 41 is driven so as to achieve this number of steps (step S440).

  Here, as shown in FIG. 6, the damping force map 2 used when it is determined that the vehicle height is being adjusted at the same vehicle speed is the damping force map 1 used when the vehicle height is not being adjusted. It is set larger than (described later).

  If the vehicle height adjustment start signal S1 or S2 is not ON (No in step S450), it is further determined whether or not the vehicle height adjustment end signal S3 or S4 is ON (step S470). .

  If the vehicle height adjustment end signal S3 or S4 is ON (Yes at Step S470), the damping force map 1 shown in FIG. 6 is used (Step S480), and the number of steps according to the read vehicle speed (Step S420). Is determined (step S430), and the right front actuator 41 is driven so as to achieve this number of steps (step S440).

  If the determination in step S470 is negative, vehicle height adjustment control is not performed, and normal damping force control may be executed. That is, the number of steps is determined from the map used during normal damping force control according to the read current vehicle speed (step S420) (step S430), and the right front actuator 41 is driven to achieve this number of steps (step S440). .

  While the damping force control is executed for the right front wheel as described above, the left front wheel and the left and right rear wheels are also controlled in the same manner as described above.

  As described above, the normal damping force control is interrupted simultaneously with the start of the vehicle height adjustment control, and the damping force is set to be larger than the damping force when the vehicle height is not being adjusted. Even when the vehicle height is deviated from the standard position, it is difficult for the bounce stopper or the rebound stopper to hit, and the ride comfort is improved. Therefore, a compressor having a relatively small capacity can be used as the vehicle height adjusting means.

  In addition, when any of the suspensions 31 to 34, the valves V0 to V4, etc. are operating normally, normal damping force control according to the vehicle speed is performed, while any of the suspensions 31 to 34 is In the event that the vehicle height is not adjusted properly due to a malfunction, switching to the damping force control (fixing the damping force to the maximum number of stages) at the time of failure can suppress the occurrence per bounding stopper or rebound stopper. it can.

  In the above-described embodiment, the suspensions 31 to 34 have been described as air spring type so-called air suspensions. However, the suspensions 31 to 34 are not limited thereto, and may be hydraulic so-called hydropneumatic suspensions. In this case, the present invention can be similarly applied.

  Further, in the abnormality determination when the vehicle height adjustment is not properly performed, the vehicle height adjustment time (elapsed time) measured by the counter is described as being used. However, the abnormality determination means is not limited to this. For example, since the drive current values of the suspensions 31 to 34 and the valves V0 to V4 at the time of adjusting the vehicle height become large at the time of abnormality, the abnormality is determined by determining whether or not the drive current value has exceeded a predetermined value. The above control may be performed, and the same effect as described above can be expected.

  As described above, the suspension control device according to the present invention is useful for a so-called air spring type air suspension that requires time to adjust the vehicle height, and particularly when the vehicle height is shifted from the standard position during vehicle height adjustment. Even if it exists, it is suitable for suspension control which can suppress generation | occurrence | production for a bound stopper or a rebound stopper with a simple structure, and can improve riding comfort.

1 is a perspective view showing an outline of a vehicle provided with a suspension control apparatus according to an embodiment of the present invention. It is a block diagram which shows a suspension control (vehicle height control) apparatus. It is a block diagram which shows a suspension control (damping force control) apparatus. It is a flowchart which shows vehicle height control. It is a flowchart which shows damping force control. It is a damping force map which shows the map used at the time of switching of the number of damping force steps.

Explanation of symbols

C vehicle 1 suspension control device 3 suspension control computer (vehicle height adjustment state determination means, abnormality detection means)
11 Right front SCA (vehicle height adjustment means)
12 Front left SCA (vehicle height adjustment means)
13 Right rear SCA (vehicle height adjustment means)
14 Left rear SCA (vehicle height adjustment means)
21 Right front vehicle height sensor (vehicle height adjustment means)
22 Left front vehicle height sensor (vehicle height adjustment means)
23 Right rear vehicle height sensor (vehicle height adjustment means)
24 Left rear vehicle height sensor (vehicle height adjustment means)
30 Compressor (vehicle height adjustment means)
31 Front right suspension (vehicle height adjustment means, damping force variable means)
32 Left front suspension (vehicle height adjustment means, damping force variable means)
33 Rear right suspension (vehicle height adjustment means, damping force variable means)
34 Left rear suspension (vehicle height adjustment means, damping force variable means)
V0 exhaust valve (vehicle height adjustment means)
V1 Right front valve (vehicle height adjustment means)
V2 Front left valve (vehicle height adjustment means)
V3 Right rear valve (vehicle height adjustment means)
V4 Left rear valve (vehicle height adjustment means)
T1, T2 Measurement time (elapsed time)

Claims (4)

Vehicle height adjusting means for adjusting the vehicle height;
A damping force variable means for changing the damping force of the suspension;
Vehicle height adjustment state determining means for determining whether or not the vehicle height is being adjusted;
With
When the vehicle height adjustment state determining means determines that the vehicle height is being adjusted, the suspension control device sets the damping force to be larger than the damping force when the vehicle height is not being adjusted. An abnormality detection means for detecting an abnormality at the time of vehicle height adjustment of the vehicle height adjustment means,
The suspension control device according to claim 1, wherein when an abnormality is detected by the abnormality detection means, the damping force by the damping force variable means is set to be larger. Comprising time measuring means for detecting an elapsed time from the start of the vehicle height adjustment,
The abnormality detecting means detects an abnormality when the elapsed time detected by the time measuring means exceeds a predetermined value, and further sets the damping force by the damping force varying means to be larger. Item 3. The suspension control device according to Item 2. A driving current measuring means for detecting a driving current value of the vehicle height adjusting means at the time of vehicle height adjustment;
When the drive current value detected by the drive current measuring means exceeds a predetermined value, the abnormality detection means detects an abnormality and sets the damping force by the damping force variable means to be larger. The suspension control device according to claim 2.

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