JP5081650B2 - Damping force control device for vehicle - Google Patents

Description

  The present invention relates to an apparatus for controlling a damping force of a vehicle suspension.

There is a technique for suppressing roll vibration and pitch vibration of a vehicle by arranging a shock absorber capable of controlling the damping coefficient in a suspension device and adjusting the damping coefficient according to the state of the vehicle. For example, in the damping force control device described in Patent Document 1, when roll vibration or pitch vibration occurs, the damping force on the rear wheel side is calculated based on the delay time of damping force control on the rear wheel side with respect to damping force control on the front wheel side. I have control. Further, for example, in the vehicle suspension device described in Patent Document 2, the shock absorber on the rear wheel side is attenuated based on a composite signal synthesized at a predetermined ratio with the bounce component signal on the rear wheel side and the pitch component signal on the rear wheel side. Force control is performed.
JP-A-9-267615 JP 7-285309 A

  When the vehicle rides on a protrusion on the road, roll vibration and pitch vibration are instantaneously generated and converged. When such an instantaneous event occurs, the driver's sensitivity is different between roll vibration and pitch vibration. The above-described conventional vehicle damping force control apparatus has room for improvement in that it does not consider such driver sensitivity.

  The present invention has been made to solve the above problems, and provides a vehicle damping force control device capable of improving driver comfort under an event in which roll vibration and pitch vibration occur instantaneously. The purpose is to provide.

  In order to solve the above problems, the present inventor has conducted a sensory test against vibration when the vehicle enters the protrusion in the process of earnest research. As a result, it was found that the sensitivity of the driver is more sensitive to roll vibration than pitch vibration. It was also found that the convergence of roll vibration and pitch vibration can be controlled within a certain range by changing the distribution of the damping force of the rear wheel side shock absorber with respect to the damping force of the front wheel side shock absorber. Therefore, the inventor of the present application controls the distribution of the damping force of the shock absorber so that the roll vibration after the vehicle enters the protrusion is controlled, under the event that the roll vibration and the pitch vibration occur instantaneously, Obtaining knowledge that the comfort of the driver can be improved, the present invention has been completed.

  A vehicular damping force control device according to the present invention is a vehicular damping force control device that controls a damping force of a shock absorber disposed in each of a front wheel side suspension device and a rear wheel side suspension device of a vehicle. Roll vibration judging means for judging whether or not roll vibration is generated in the vehicle, and when the roll vibration judging means judges that roll vibration has occurred, the shock absorber on the front wheel side attenuates against the damping force of the shock absorber on the rear wheel side It is characterized by comprising attenuation distribution setting means for performing a first control for making the force distribution ratio larger than that in the normal state.

  In this vehicle damping force control device, when roll vibration occurs when a vehicle enters a protrusion on the road, the distribution ratio of the damping force of the front wheel side shock absorber to the damping force of the rear wheel side shock absorber is normally set. By making it larger than the state, roll vibration can be effectively suppressed. Since the driver's sensitivity is more sensitive to roll vibration than pitch vibration, the driver's comfort can be improved by suppressing the roll vibration that occurs instantaneously when the protrusion enters.

  The damping distribution setting means follows the first control, and performs a second control for reducing the distribution ratio of the damping force of the shock absorber on the front wheel side to the damping force of the shock absorber on the rear wheel side from the normal state. Preferably it is done. After suppressing the roll vibration that occurs instantaneously when the protrusion enters, the roll vibration is suppressed by making the distribution ratio of the damping force of the shock absorber on the front wheel side to the damping force of the shock absorber on the rear wheel side smaller than the normal state. After that, the pitch vibration can be quickly suppressed. As a result, the driver's comfort can be further improved.

  According to the vehicular damping force control device of the present invention, it is possible to improve driver comfort under an event in which roll vibration and pitch vibration occur instantaneously.

  Hereinafter, a preferred embodiment of a vehicular damping force control apparatus according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a vehicle equipped with a vehicle damping force control apparatus according to an embodiment of the present invention. This vehicle is provided with front wheels 10 _FL and 10 _FR and rear wheels 10 _RL and 10 _RR , and suspension devices 11 _FL , 1 _FR , 11 _RL and 11 _RR are respectively provided.

The suspension devices 11 _FL , 11 _FR , 11 _RL , 11 _RR are shock absorbers 12 _FL , 12 _FR , 12 _RL , 12 _RR and suspension actuators 13 _FL , 13 _FR , 12 _RR for adjusting the damping force (damping coefficient) of the shock absorber. 13 _RL , 13 _RR, and stroke sensors 15 _FL , 15 _FR , 15 _RL , 15 _RR for detecting the stroke amount.

Output signals (stroke amounts) from the stroke sensors 15 _FL , 15 _FR , 15 _RL , and 15 _RR are a lateral G sensor 21 that detects a lateral acceleration of the vehicle, a gyro sensor 22 that detects a roll angular velocity and a yaw angular velocity of the vehicle, and Along with an output signal from each sensor group such as a vehicle speed sensor 23 for detecting the vehicle speed, it is input to an electronic control unit (ECU) 2 constituting the vehicular damping force control device 1.

  The ECU 2 is physically a control unit including a ROM, a RAM, a CPU, and the like. As shown in FIG. 2, the ECU 2 includes a roll vibration determination unit 101, a vehicle specification value storage unit 102, a damping distribution setting unit 103, and a suspension control unit 104 as functional components. .

  The roll vibration determination unit 101 is a part that determines whether roll vibration has occurred in the vehicle. The roll vibration determination unit 101 acquires output signals from the lateral G sensor 21, the gyro sensor 22, the vehicle speed sensor 23, and the stroke sensor 15 at a predetermined period.

  When the roll vibration determination unit 101 acquires each output signal, the roll vibration determination unit 101 refers to the vehicle specification value storage unit 102 and acquires specification values such as the weight of the vehicle, the height of the center of gravity, and the wheel base. The roll vibration determination unit 101 is a behavior detection value including a threshold set based on the vehicle specification value, a lateral acceleration obtained from each sensor 15, 21, 22, 23, a roll angle, a vehicle speed, a stroke amount, and the like. To determine whether or not roll vibration has occurred in the vehicle.

The damping distribution setting unit 103 determines a damping force distribution ratio (hereinafter referred to as “damping distribution”) between the front wheel side shock absorbers 12 _FL and 12 _FR and the rear wheel side shock absorbers 12 _RL and 12 _RR. This is the part to set. The damping distribution is set in a state where the total sum of the damping forces in the shock absorbers 12 _FL and 12 _FR and the rear wheel side shock absorbers 12 _RL and 12 _RR is constant. The damping distribution is set to, for example, front wheel side: rear wheel side = 50%: 50% during normal traveling.

  When the roll vibration determining unit 101 determines that roll vibration has occurred, the attenuation distribution setting unit 103 sets the attenuation distribution to, for example, front wheel side: rear wheel side = 60%: 40%, and the attenuation distribution is in a normal state. To the front side (first control). Further, the attenuation distribution setting unit 103 changes the attenuation distribution to the front side, then sets the attenuation distribution at a predetermined timing, for example, front wheel side: rear wheel side = 40%: 60%, and sets the attenuation distribution more than the normal state. Change to the rear side (second control).

The suspension control unit 104 is a part that controls the suspension actuators 13 _FL , 13 _FR , 13 _RL , 13 _RR and adjusts the damping force of the shock absorbers 12 _FL , 12 _FR , 12 _RL , 12 _RR . The suspension control unit 104 maintains the damping force of the shock absorbers 12 _FL , 12 _FR , 12 _RL , 12 _RR based on the damping distribution set by the damping distribution setting unit 103.

  Next, the operation of the vehicular damping force control apparatus 1 having the above-described configuration will be described. FIG. 3 is a flowchart showing the operation of the vehicular damping force control apparatus 1. This control is repeatedly executed by the ECU 2 from the start to the stop of the vehicle engine, for example, at intervals of 0.1 seconds.

  First, acquisition of various behavior detection values and acquisition of vehicle specification values based on output signals from the lateral G sensor 21, the gyro sensor 22, the vehicle speed sensor 23, and the stroke sensor 15 are performed (step S01). Next, the presence or absence of occurrence of roll vibration in the vehicle is determined by comparing these behavior detection values and vehicle specification values with threshold values (step S02).

If it is determined in step S02 that roll vibration has occurred, the damping distribution of the shock absorbers 12 _FL , 12 _FR , 12 _RL , 12 _RR is set closer to the front (step S 03). Then, after the roll flag is set to ON (step S04), the process ends.

  On the other hand, if it is determined in step S02 that roll vibration has not occurred, it is next determined whether or not the roll flag is ON (step S05). If it is determined in step S05 that the roll flag is OFF, roll vibration is not currently generated, and the damping distribution is not changed in step S03 in the previous control. This state indicates that the vehicle has not entered the protrusion or the like, and the process ends without controlling the attenuation distribution.

If it is determined in step S05 that the roll flag is ON, the occurrence of roll vibration is determined in the previous control, the damping distribution is changed to the front side, and no roll vibration is currently generated ( That is, the roll angle is converged below a certain level). This state indicates that the vehicle has already passed through the protrusion after entering the protrusion. In this case, the damping distribution of the shock absorbers 12 _FL , 12 _FR , 12 _RL , 12 _RR is set closer to the rear (step S06), the roll flag is set to OFF (step S07), and the process ends.

  Then, the effect of the damping force control apparatus 1 for vehicles is demonstrated.

FIG. 4 is a diagram illustrating an example of a relationship between roll vibration and pitch vibration when the vehicle enters the protrusion and damping distribution of the shock absorbers 12 _FL , 12 _FR , 12 _RL , and 12 _RR . As shown in the figure, when the damping distribution is set to the front wheel side: rear wheel side = 40%: 60%, the roll angle varies in the range of about -0.05 rad to +0.25 rad, and the pitch angle is It fluctuated in the range of about -0.05 rad to +0.1 rad.

  When the damping distribution is set to front wheel side: rear wheel side = 60%: 40%, the roll angle varies in a range of about −0.03 rad to +0.22 rad, and the pitch angle is −0.2 rad to It fluctuated in the range of about 0.15 rad. From these results, it can be seen that roll vibration tends to be suppressed when the damping distribution is set closer to the front, and pitch vibration tends to be suppressed when the attenuation distribution is set closer to the rear.

  FIG. 5 is a diagram showing fluctuations of the roll vibration and pitch vibration shown in FIG. 4 along the time axis. As shown in FIGS. 5A and 5B, when the vehicle enters the protrusion, the roll angle first increases rapidly. The roll angle variation converges rapidly when the vehicle passes the protrusion. On the other hand, it can be seen that the pitch angle remains cyclically varied a plurality of times even after the vehicle has passed the protrusion.

With respect to such behavior of roll vibration and pitch vibration, the vehicular damping force control device 1 causes the rear wheel side shock absorbers 12 _RL , 12 when the vehicle enters roll protrusions and the like to generate roll vibration. _{By making} the damping distribution of the shock absorbers 12 _FL and 12 _FR on the front wheel side with respect to the damping force of _RR larger than the normal state, roll vibration can be effectively suppressed. Since the driver's sensitivity is more sensitive to roll vibration than pitch vibration, the driver's comfort can be improved by suppressing the roll vibration that occurs instantaneously when the protrusion enters.

Further, in the vehicle damping force control apparatus 1, after suppressing the instantaneous roll vibration generated during projection enters, the shock absorber 12 of the rear wheel _RL, 12 front side of the shock absorber for damping the _RR 12 _FL, 12 _{By making the FR} attenuation distribution smaller than the normal state, the pitch vibration after suppressing the roll vibration can be quickly suppressed. As a result, the driver's comfort is further improved.

1 is a schematic configuration diagram of a vehicle equipped with a vehicle damping force control apparatus according to an embodiment of the present invention. It is the figure which showed the functional component of ECU. It is a flowchart which shows operation | movement of the damping force control apparatus for vehicles shown in FIG. It is the figure which showed an example of the relationship between roll vibration and pitch vibration when a vehicle approachs protrusion, and attenuation distribution. It is the figure which showed the fluctuation | variation of the roll vibration and pitch vibration shown in FIG. 4 along the time axis.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle damping force control apparatus, 2 ... ECU, _11FL , _11FR , _11RL , _11RR ... Suspension apparatus, _12FL , _12FR , _12RL , _12RR ... Shock absorber, 101 ... Roll vibration judgment part, 103: Attenuation distribution setting unit.

Claims (2)

A vehicular damping force control device for controlling a damping force of a shock absorber respectively disposed on a front wheel side suspension device and a rear wheel side suspension of a vehicle,
Roll vibration determining means for determining whether or not roll vibration occurs in the vehicle;
When it is determined by the roll vibration determination means that the roll vibration has occurred, the rear wheel side shock absorber is maintained in a state where the sum of damping forces in the front wheel side shock absorber and the rear wheel side shock absorber is constant. the front wheel side vehicular damping force control apparatus being characterized in that a damping distribution setting means for performing a first control to be larger than the normal state distribution ratio of the damping force of the shock absorber for damping force. The damping distribution setting means follows the first control, with the sum of damping forces in the front wheel side shock absorber and the rear wheel side shock absorber being constant, and the rear wheel side shock absorber. The vehicular damping force control apparatus according to claim 1, wherein a second control is performed to reduce a distribution ratio of the damping force of the shock absorber on the front wheel side to a damping force of the front wheel to be smaller than a normal state.

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