JP2012206560A - Suspension control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suspension control device capable of improving riding comfort when riding over a projection especially while a vehicle is running on a rough road.SOLUTION: In a control method of a controller of a suspension control device, even when the projection ride-over determination is established by a projection ride-over determination unit during the rough road travel control, the rough road travel control is continued. Thus, when a vehicle rides over a projection while traveling a rough road, the damping characteristic becomes the softer control than a conventional one, and the riding comfort can be improved.

Description

  The present invention relates to a suspension control device that controls a damping force characteristic of a shock absorber used in a vehicle.

  In the suspension control device according to Patent Document 1, when a vehicle rides over a protrusion on the road surface while traveling on a relatively flat road surface (ordinary road), if the protrusion overriding determination is established based on various control parameters of the control means, immediately after overriding the protrusion The shock absorber is hard-controlled at the optimal timing by monitoring the stroke of the shock absorber.

JP 2010-235019 A

  Therefore, in the suspension control device according to Patent Document 1, when the road surface is determined to be a bad road by the bad road determination unit, the vehicle travels on the rough road traveling control, that is, the damping force is higher than that on the normal road traveling control. The characteristic is driven with soft control, but when the vehicle gets over a bump while riding on a rough road, if the bump over judgment is established, the over bump running control is executed and the damping force characteristic is hard when appropriate after the bump is over. Since it is controlled (harder than the damping force characteristic of normal road traveling control), there is a problem that the riding comfort deteriorates.

  It is an object of the present invention to provide a suspension control device that improves the ride comfort when riding over a protrusion while traveling on a rough road.

As means for solving the above-mentioned problems, the first invention is a suspension control device for controlling damping force characteristics of a damping force adjusting type shock absorber interposed between a vehicle body and wheels by a control means, The control means includes a rough road determination unit and a protrusion overpass determination unit, and performs rough road traveling control when the rough road determination unit determines a bad road, and when the rough road traveling control is not in progress, the protrusion When the overpass determination is established by the overpass determination unit, the overpass control with a greater damping force characteristic than the rough road control is performed. During the rough road control, the overpass determination is established by the overpass determination In this case, the rough road traveling control is continued without performing the protrusion overrunning control.
Further, the second invention is a suspension control device for controlling the damping force characteristic of a damping force adjusting type shock absorber interposed between the vehicle body and the wheel by the control means, wherein the control means determines a bad road. And a projection overpass determination unit that performs rough road traveling control when the rough road determination unit determines a rough road, and when the rough road traveling control is not being performed, the projection overdetermination unit When it is established, the bump overriding running control having a damping force characteristic larger than that of the rough road running control is performed, and when the bump overriding judgment is established by the bump overriding determination unit during the bad road running control, the bump overriding is performed. The damping force characteristic is made smaller than that of the traveling control.

  According to the suspension control device of the present invention, it is possible to improve the ride comfort when riding over a protrusion, particularly while traveling on a rough road.

It is a mimetic diagram of a suspension control device concerning an embodiment of the invention. It is a flowchart which shows the control method which concerns on 1st Embodiment of the controller of this suspension control apparatus. It is a flowchart which shows the control method which concerns on 2nd Embodiment of the controller of this suspension control apparatus. It is the figure which compared transition of the spring vertical acceleration etc. in the suspension control apparatus which concerns on embodiment of this invention, and the conventional suspension control apparatus.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to FIGS.
A suspension control apparatus 10 according to the present embodiment includes a suspension spring 3 and a damping force variable shock absorber 4 (a damping force adjusting shock absorber) between a vehicle body 1 (on a spring) and each wheel 2 (unsprung) of a vehicle. The controller 7 as a control means calculates a target damping force from the running state of the vehicle obtained from the sprung acceleration sensor 5 and the unsprung acceleration sensor 6, etc. The shock absorber 4 is controlled so that a target damping force is generated.

  The controller 7 determines the vibration state or vibration suppression state of the vehicle body 1 based on the detection signals from the spring vertical acceleration sensors 5 and 6 according to the so-called skyhook theory. In the state, the target damping force is calculated to increase the damping force, and the damping force of the shock absorber 4 of each wheel 2 is controlled to optimally adjust the vibration characteristics transmitted from the wheel 2 to the vehicle body 1. Stabilize 1 in a flat state.

Moreover, the controller 7 determines the road surface state currently drive | working by a road surface determination process part based on the detection signal from the spring vertical acceleration sensors 5 and 6 grade | etc.,. The road surface determination processing unit includes a normal road determination unit, a wavy road determination unit, a rough road determination unit, a violent road determination unit, and the like. In each determination unit, each of the road surface determination processing units is based on detection signals from the spring vertical acceleration sensors 5 and 6. The road surface state is determined by comparing with a threshold value (map) related to road surface determination and grasping the time passage of the state. The road surface condition is determined according to the detection signals from the spring vertical acceleration sensors 5, 6, etc., when the amplitude of the acceleration signal is medium to large and the frequency is low (for example, near the sprung resonance frequency of 1 Hz). The state is determined as “swell road”. In addition, when the amplitude of the acceleration signal is small to medium and the frequency is medium to high (for example, near the unsprung resonance frequency of 10 Hz), the road surface state is determined as “bad road”, and other cases are determined. Judged as “ordinary road”. As a result, when the acceleration signal amplitude is small to medium and the frequency is low to medium, and when the amplitude is medium to large and the frequency is slightly higher than low and high, the road surface condition is set to “normal”. Road ". These “swell road”, “bad road”, and “normal road” are determined when the state continues for a predetermined time. On the other hand, the protrusion is determined when there is an input with a single amplitude larger than the wave path.
The rough road determination unit will be described next. The rough road determination unit calculates the number of times that the amplitude of the acceleration signal from the spring vertical acceleration sensors 5 and 6 is within a predetermined time within the range of the rough road reference value, and the number of times is equal to or greater than the predetermined value. Is determined, the rough road flag is set and it is determined that the road is in a rough road state. Next, the protrusion over determination unit will be described. The controller 7 is provided with a protrusion overriding determination unit, which calculates the relative speed in the vertical direction of the vehicle body 1 and the wheel 2 based on detection signals from the spring vertical acceleration sensors 5, 6 and the like. Based on the calculation data of the relative speed, the protrusion overdetermining determination unit determines that the protrusion has been applied when a contraction stroke having a magnitude exceeding a predetermined first threshold is detected. If an extension stroke having a size exceeding the second threshold is detected, it is determined that the protrusion has been passed. Note that the determination method of the rough road determination unit and the protrusion over-determination determination unit is not limited to this. For example, even if a projection is detected using a preview sensor or a change in internal pressure of the shock absorber is detected, road surface determination may be performed. Good.

  Then, the controller 7 performs road surface determination based on detection signals from the spring vertical acceleration sensors 5 and 6, and based on the result, a control signal (damping force-current characteristic) stored in advance is multiplied by a predetermined control gain. Then, a control signal corresponding to each road surface is output to the actuator 8, and the generated damping force by the shock absorber 4 is changed by the actuator 8 so that traveling control (damping force control) corresponding to each road surface is performed.

  In the rough road traveling control corresponding to the bad road, the damping force characteristic is softer than the normal road traveling control corresponding to the normal road. In addition, when the vehicle passes over a protrusion while driving on a normal road, the protrusion overriding travel control corresponding to the protrusion overtaking is performed. The hard control having a greater damping force characteristic than the road traveling control (bad road traveling control) is executed.

Next, a control method of the suspension control apparatus 10 according to the present embodiment will be described with reference to FIGS.
First, a control method according to the first embodiment of the controller 7 will be described based on the flowchart of FIG.
In the control method according to the first embodiment, first, in step S1, the rough road determination unit of the controller 7 determines whether or not the road surface is a bad road, and when it is determined that the road is a bad road. Proceeds to step S2, while if it is determined that the road is not a rough road, the process proceeds to step S101.
Next, in step S2, a control signal corresponding to the rough road is output from the controller 7 to the actuator 8, and the shock absorber 4 attenuates the road more than the rough road traveling control corresponding to the rough road, that is, the normal road traveling control. Soft control with a small force characteristic is executed.

Next, in step S3, when the vehicle rides over the bump on the rough road and the bump ride judgment unit establishes the bump ride judgment, the controller 7 outputs a control signal corresponding to the bump ride to the actuator 8. In step S4, the control signal is obtained by multiplying the damping force characteristic of the overpass travel control on a normal road by the control gain K (K <0), that is, the damping force characteristic of the overpass travel control during a rough road is The damping force control in the shock absorber 4 is started when the damping force characteristic is set to be larger than the damping force characteristic of the rough road traveling control and smaller than the damping force characteristic of the bump overrunning traveling control during the normal road traveling. On the other hand, if it is determined in step S3 that the protrusion overpass determination has not been established, the process ends.
Next, in step S5, a counter is started when the damping force control in the shock absorber 4 is started in step S4.
Next, in step S6, it is determined whether or not the counter has reached a predetermined value. When it is determined that the counter has reached the predetermined value, the process proceeds to step S7, and the protrusion overrunning control started in step S4 ends. Then, it progresses to step S8 and a counter is cleared. In step S6, if the counter does not reach the predetermined value, the process returns to immediately before step S6.

  In step S1, if the rough road determination unit of the controller 7 determines that the road is not a bad road, the process proceeds to step S101. In step S101, when the vehicle travels on a road surface other than the bad road, When the projection overriding determination unit is established in the projection overriding determination unit, a control signal corresponding to the projection overriding is output from the controller 7 to the actuator 8. The control signal is a normal road traveling control (bad road traveling control). In step S102, the damping force control in the shock absorber 4 is started at an appropriate timing after getting over the protrusion.

Next, in step S103, the counter is started when the damping force control in the shock absorber 4 is started in step S102.
Next, in step S104, it is determined whether or not the counter has reached a predetermined value. When it is determined that the counter has reached the predetermined value, the process proceeds to step S105, and the over-projection control for protrusions started in step S102 (the over-protrusion control during normal road travel) is completed. Then, it progresses to step S106 and a counter is cleared. If the counter does not reach the predetermined value in step S104, the process returns to immediately before step S104.
Further, in step S101, when the protrusion overdetermining unit of the controller 7 does not establish the protrusion overtaking determination, the process ends.

Next, a control method according to the second embodiment of the controller 7 will be described based on the flowchart of FIG.
In the control method according to the second embodiment, in step S201, the rough road determination unit of the controller 7 determines whether or not the road surface is a bad road. On the other hand, if it is determined that the road is not a rough road, the process proceeds to step S101.
Next, in step S202, a control signal corresponding to a rough road is output from the controller 7 to the actuator 8, and the shock absorber 4 attenuates the rough road traveling control corresponding to the rough road, that is, the normal road traveling control. Soft control with a small force characteristic is executed.

Next, in step S203, when the vehicle rides over the bump on the rough road, even if the bump over determination is established in the bump over determination unit, the rough road control is continued in step S204, and the shock absorber 4 is attenuated. Force control is maintained as rough road control.
On the other hand, if it is determined in step S203 that the protrusion overriding determination unit does not determine the protrusion overriding, the process ends.

  In step S201, when the rough road determination unit of the controller 7 determines that the road is not a bad road, the process proceeds to step S101, which is the same as steps S101 to S106 of the control method according to the first embodiment. Processing is executed.

  FIG. 4 is a comparison of changes in the vertical acceleration of the spring between the conventional suspension control device and the suspension control device 10 according to the present embodiment. The dotted line indicates the conventional suspension control device, and the solid line indicates the present embodiment. The suspension control apparatus which concerns on a form is shown. In FIG. 4, the above-described second embodiment is adopted as the control method of the controller 7 in the suspension control apparatus 10 according to the present embodiment.

  As can be seen from FIG. 4, in the suspension control device 10 according to the present embodiment, even when the vehicle rides over a protrusion while traveling on a rough road, the protrusion control over the protrusion is not executed and the rough road traveling control is continued. 4 (refer to the transition of the current value (A) and the estimated damping force), referring to the portions A and B in FIG. 4, fluctuations in the sprung acceleration and the sprung speed are smaller than those in the conventional suspension control device. It can be seen that the transmission of vibration to the vehicle body 1 is small and the riding comfort is improved.

As described above, in the suspension control apparatus 10 according to the embodiment of the present invention, as the first embodiment of the control method by the controller 7, when the vehicle passes over the protrusion while traveling on a rough road, the controller 7 To the actuator 8 is output a control signal obtained by multiplying the damping force characteristic of the bump overrunning control on the normal road by the control gain K (K <0). In the second embodiment, the rough road traveling control is continued even when the vehicle passes over the protrusion while traveling on the rough road. In other words, in both the first and second embodiments, the protrusion overrunning control when traveling on a rough road is controlled so that the damping force characteristic is smaller than the protrusion overrunning control during normal road traveling.
As a result, as shown in FIG. 4, when the vehicle rides over the protrusion while traveling on a rough road, the damping force characteristic is softer than in the conventional case, so that the ride comfort can be improved.

  DESCRIPTION OF SYMBOLS 1 Vehicle body, 2 Wheel, 4 Damping force variable shock absorber (damping force adjustment type shock absorber), 5 Spring acceleration sensor, 6 Unsprung acceleration sensor, 7 Controller (control means), 8 Actuator, 10 Suspension control device

Claims (2)

A suspension control device for controlling a damping force characteristic of a damping force adjustment type shock absorber interposed between a vehicle body and a wheel by a control means,
The control means includes a rough road determination unit and a protrusion overpass determination unit,
When rough road determination is performed by the rough road determination unit, rough road running control is performed,
When it is not during the rough road traveling control, when the protrusion overcoming determination unit establishes the protrusion overriding determination, the bump overrunning control having a damping force characteristic larger than the rough road traveling control is performed,
The suspension control device according to claim 1, wherein during the rough road traveling control, when the bump over determination is established by the protrusion over determination unit, the rough road traveling control is continued without performing the protrusion overrun control. A suspension control device for controlling a damping force characteristic of a damping force adjustment type shock absorber interposed between a vehicle body and a wheel by a control means,
The control means includes a rough road determination unit and a protrusion overpass determination unit,
When rough road determination is performed by the rough road determination unit, rough road running control is performed,
When it is not during the rough road traveling control, when the protrusion overcoming determination unit establishes the protrusion overriding determination, the bump overrunning control having a damping force characteristic larger than the rough road traveling control is performed,
A suspension control device characterized in that a damping force characteristic is made smaller than that in the protrusion overtravel control when the protrusion overpass determination is established during the rough road travel control.

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