JPH06143958A - Suspension control device - Google Patents

Abstract

PURPOSE:To provide a suspension control device capable of substantially improving ride comfort ableness by accurately estimating direct vibration sensed by crew members, and most suitably controlling the characteristics of a suspension on the basis of the estimation. CONSTITUTION:As shown in Fig.4, acceleration detecting means, that is, seat back sensors 10a, 10b and seat seating face sensor 11a, 11b are fixed in a manner that they are sandwiched between a human body and sear cushion after crew members determine their respective operating positions. Concretely, the seat back sensor 10a detects up and down acceleration of the seat back, the seat back sensor 10b detects back-and-forth acceleration of the seat back, the seat seating face sensor 11a detects up and down acceleration of the seat seating face, and the seat seating face sensor 11b detects back-and-forth acceleration of the seat seating face.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle suspension control device.

[0002]

2. Description of the Related Art An automobile encounters every running condition from a flat road surface to an irregular portion such as a seam of the road surface, and it is necessary to appropriately suppress vibrations according to the running condition. For example, when traveling ardently, an occupant is particularly sensitive to irregularities in vehicle vibration and feels uncomfortable when riding through joints on an overpass or joints on a paved road.

In conventional suspension control devices for automobiles, the sprung unsprung relative displacement on the axle of the vehicle, the vibration acceleration of the vehicle compartment, etc. are evaluated to evaluate the suspension damping characteristics, spring characteristics, or active control. The characteristics are variable.

[0004]

However, in the above-mentioned conventional method, even if the determination is made by a signal faithful to the movements of the wheels encountered by the vehicle and the movements of the pitch, roll, etc. of the vehicle interior, the occupant's feeling is not felt. However, there is a problem in that a proper motion state cannot be detected and the control does not accurately correspond to the ride comfort of the occupant.

That is, the riding comfort sensitivity in a running state needs to be evaluated by a direct vibration evaluation amount transmitted to an occupant, and an evaluation amount according to a human vibration sensation is introduced to determine a suspension characteristic of an automobile. It must be controlled accurately.

Therefore, the present invention has been made in view of the above problems. By accurately evaluating the direct vibration that the occupant experiences, and optimally controlling the characteristics of the suspension based on the evaluation, An object of the present invention is to provide a suspension control device capable of significantly improving comfort.

[0007]

In order to achieve the above object, the inventors of the present invention repeatedly conducted systematic experimental analysis, and as a result, the feeling of the passenger, who is an evaluator of the riding comfort, was determined to be the vibration acceleration near the passenger due to the vibration of the automobile. We have found that we can make more accurate judgments based on the evaluation amount including the directionality of. Then, in order to control the vibration of the automobile, it was found that it is necessary to pay attention to the vibration stimulus amount based on the vibration acceleration in the vertical and front-back directions on the seat surface and the back surface of the occupant in the driving sitting posture. It has arrived.

That is, the suspension control device according to the present invention is embedded in the seat seat surface and the seat back surface, and detects acceleration and / or deceleration acting on the occupant when seated in the up and down direction or in the longitudinal direction. A vibration stimulus amount calculation means for calculating the vibration stimulus amount based on the amplitude and phase of the output of the means; and a control means for determining the vibration stimulus to the occupant based on the amplitude and phase and changing the suspension system characteristic of the vehicle. It is characterized by being provided.

(Principle of the Invention) The inventors of the present application traveled in various running conditions on various road surfaces with respect to vibration stimulation to an occupant on a traveling vehicle, and calculated the amount of stimulation to the occupant at that time from various evaluation values. investigated. Then, it was clarified that the vibration stimulus amount in the vicinity of the occupant influences the occupant's feeling rather than the whole vehicle and the parts related to the wheels such as the axles. Furthermore, as for the vibration stimulus amount, it was noticed that the magnitude and direction of the stimulus to the occupant's spinal column, which are closely related to the occupant's posture when the seat is seated, are the influential factors on the seat seat surface and the back surface. That is, the amount of stimulation to the occupant in a normal vehicle is investigated in detail, and the stimulation vector to the spinal column in the sitting posture is considered. From the amplitude and phase difference, we found that the relationship between the change in the amount of stimulation to the spinal column and the riding comfort was clear.

Based on this point of view, the stimulus amount of the seat seat surface and the back surface was quantitatively evaluated by the acceleration waveform vector in some cases of the irregular road surface. As a result, as shown in FIG. It has been clarified that when the vector sum (amplitude) of the acceleration waveforms formed by the vertical longitudinal acceleration is large and the angle (phase) formed by the vectors is large, the occupant's riding comfort is significantly impaired. That is, the vibration stimulus on the seat surface means that the spinal column is pushed up and the excitation level to the internal organs of the chest is large, and the vibration stimulus on the back surface acts to push up the thoracic vertebra, and the cervical vertebrae and the head above the thoracic vertebrae. It means that the excitation level to is increased. Therefore, when the stimulus amount is large, the occupant determines that the riding comfort will be significantly deteriorated.Therefore, the threshold value of the stimulus amount is set to the vehicle level at which the current ride comfort evaluation is high, and the threshold value is used as the reference value for control. It was clarified that the vibration control that matches the ride comfort of the occupant can be performed by determining the signal output.

[0011]

The present detection site is located on the seat surface and the back surface of the seat, and is set at a position where the stimulus to the occupant, who is the occupant, is grasped most accurately. That is, in the seat part where the seat pressure of the seat occupant support is highest, it is directly below the lumbar greater trochanter, and in the back part, it corresponds to the tenth thoracic vertebra back part. Although the occupant changes the seat posture according to personal preference,
The maximum stimulus site to the human body when taking the optimum driving posture is limited to this area.

[0012]

According to the present invention having the above-mentioned structure, the amount of vibration generated in the vertical and front-back directions of the vibration acceleration of the seat surface and the back of the seat in the sitting posture of the occupant, which is closely related to the sensation of vibration of the occupant, is detected, and the occupant is vibrated. The suspension system characteristics control is performed after accurately assessing the vibration stimulus in the running state by discriminating the amount, and thus it is more accurate than the conventional technology that detects the relative displacement of the axle and the vibration acceleration on the floor of the passenger compartment. It is possible to evaluate the vibration stimulation amount to the occupant. Therefore, the riding comfort of the automobile can be significantly improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described in detail below with reference to the drawings. In the first embodiment, the acceleration detecting means for detecting the vertical acceleration of the seat surface of the occupant's seating position and the longitudinal acceleration of the back surface, and the acceleration from the acceleration detecting means are waveform-shaped by a predetermined band pass filter. A bandpass filter, a calculation determination value obtained by calculating the amplitude and phase of the signal waveform output from the acceleration detecting means by the waveform-shaped acceleration signal, the vertical rising on the seat surface of the occupant, and the rear surface The synthetic force formed by the forward and backward extrusion, that is, a comparison circuit that compares a predetermined reference value indicating the magnitude of vibration stimulation to the occupant's waist, and the output of the comparison circuit It is characterized in that it has a judging circuit for judging the magnitude, and controls the suspension system characteristic control means of the vehicle based on an output signal of the judging circuit.

As shown in FIG. 1, in the first embodiment, a seat back longitudinal acceleration detecting means I ₁ ′ for detecting longitudinal acceleration of the seat back and a seat seat surface for detecting vertical acceleration of the seat seat surface are provided. Vertical direction detecting means I ₂ ′ and vibration stimulus amount calculating means II _V ′ including a band pass filter circuit I ₃ ′, I ₄ ′ that passes only a predetermined band band of each output signal and a gain discriminating circuit and a phase discriminating circuit II _V ′. , II
_H ', the vibration reference value determination circuit III', the control signal generating circuit IV _1', the vehicle speed sensor IV ₂ ', suspension control sequence selection circuit IV _3', and consists of a control valve drive signal generating circuit V'.

In the present embodiment, the vector sum and the phase are calculated by the acceleration signal waveform-shaped by the predetermined bandpass filters of the bandpass filter circuits I ₃ ′ and I ₄ ′, so that the vibration stimulus to the occupant is more clear. It has the advantage that it can be evaluated. It is known that this band-pass filter can determine the evaluation state quantity more clearly in the case of a narrow band filter near 4 to 8 Hz, which is highly sensitive to vibration stimuli to humans, or around 7 to 8 Hz for sudden stimuli.

Next, in the vibration reference value judgment circuit III ', it is judged whether or not to enter the control mode based on the control reference value based on the sensory evaluation of the occupant. For this determination, a normal threshold value determination circuit is used.

In this embodiment having such a structure, the amount of vibration generated is detected and discriminated by the vibration acceleration in the vertical direction of the seat seat surface and the back-and-forth direction of the back surface in the seated posture of the occupant, which is closely related to the vibration sensation of the occupant. With this, the suspension system characteristic control is performed after accurately evaluating the vibration stimulus to the lumbar region of the occupant in the running state, so that the riding comfort of the vehicle is significantly improved.

Next, a second embodiment will be described. In the second embodiment, the state determination amount obtained by arithmetically processing the vector sum and phase of each of the vertical and front-back vibration accelerations at the seat seat surface and the back surface is used.

As shown in FIG. 3, in the second embodiment, the vibration stimulus amount calculating means I including acceleration detecting means I _{1 to} I ₄ , gain determining circuits G ₁ and G ₂ and phase determining circuits P ₁ and P _{2 is} used.
I _V, II _H , control determination means III including a control reference value determination circuit and driver I including a control signal generation circuit, vehicle speed sensor, control sequence selection circuit, and drive signal generation circuit
V, a driving means V driven by a driver and a control suspension VI characteristically selected by the driving means.

As shown in FIG. 4, the acceleration detecting means I _{1 to} I ₄ are seat back surface sensors 10a, 10b and seat seat surface sensors 11a, 1 embedded in the seat back surface and seat surface.
1b, the occupant determines his / her driving posture and is fixed between the human body and the seat cushion.
Specifically, the seat back sensor 10a detects the seat back vertical acceleration, the seat back sensor 10b detects the seat back longitudinal acceleration, the seat seat surface sensor 11a detects the seat seat vertical acceleration, and the seat seat surface sensor. 11b detects a seat seat longitudinal acceleration.

The acceleration detection signal of each part is shown in FIG.
Vibration stimulation amount calculation means II shown_V,II _HEnter and see in Figure 6.
As shown, is the vector sum of vertical acceleration and longitudinal acceleration?
Vibration stimulus judgment calculation amount M₁, M₂, Φ₁, Φ₂Seeking
It

Next, in the control determination means III, the control reference value (M ₁₀ , φ ₁₀ ) (M ₂₀ , φ) based on the sensory evaluation of the occupant.
₂₀ ) determines whether to enter the control mode. For this determination, the determination maps shown in FIGS. 7 (a) and 7 (b) are used, and the vibration stimulation determination calculation amounts (M _1, φ ₁ ) and (shown in the vibration stimulation calculation means II _V, II _H in FIG. 5 are used. M _2, as a vibration stimulates the extracted amount of each operation quantity of phi _2), the control reference value (M _10,
phi ₁₀₎ (if M _20, entering the phi ₂₀₎ inside (the hatched portion in the drawing)
The judgment value for entering the control mode is output to.

In the driver IV, the drive control amount is determined according to the output of the control determination means III, and a signal is output to the drive means V. In the drive means V, the control proportional flow rate control valve V ₁ , the spring on / off valve V ₂ , the damping force multistage switching valve V ₃ , the main gas spring accumulator V ₄ , the sub accumulator V ₅ , the actuator V _{6 in FIG} .
It controls each control element of the independent suspension type airflow fluid type control suspension VI including the piston V ₇ , the lower arm V ₈ , and the wheel V ₉ . Although only the front wheels are shown in FIG. 8, in the independent suspension type airflow fluid suspension similar to the front and rear wheels, the vehicle sprung vibration is reduced according to a predetermined control sequence, and the state evaluation amount for the occupant is set to a predetermined value. It is controlled so that it is less than the stimulation amount. For example, when the vector sum or the phase difference of the vibration acceleration of the seat seat and the back is larger than a predetermined value, the spring and damping characteristics of the front wheel are reduced to supply and discharge a predetermined flow rate, while the rear wheel The spring and damping characteristics are increased to discharge and supply a specified flow rate.

FIG. 9 shows a comparison between the present embodiment and the prior art (which controls the damping force of the suspension based on the relative displacement of the sprung and unsprung portions of the vehicle). It can be seen from FIG. 9 that the present embodiment has less vibration (vertical acceleration and longitudinal acceleration) exerted on the occupant as compared with the prior art.

Since the suspension control device of the present embodiment having the above-mentioned configuration gives control based on the evaluation state quantity around the occupant, it recognizes the vibration stimulus to the occupant more quickly than the control based on the movement of the entire vehicle, and makes fine adjustment. It is possible to provide various vibration controls. Moreover, since the stimulus amount to the occupant has an evaluation standard, it is possible to give a control timing according to the occupant's feeling of riding comfort, and the riding comfort feeling can be significantly improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment.

FIG. 2 is a Lissajous waveform diagram of vertical longitudinal acceleration on a seat surface and a back surface when traveling on an irregular road surface.

FIG. 3 is a block diagram showing a configuration of a second embodiment.

FIG. 4 is an explanatory view showing a mounting position of an acceleration sensor.

FIG. 5 is a block diagram illustrating in detail the acceleration detecting means and the vibration stimulus amount calculating means in the second embodiment.

FIG. 6 is a graph for obtaining a vibration stimulus determination calculation amount.

FIG. 7 (a) is a control map made up of M _{1 and} φ ₁ for determining whether to enter a control mode. (B) A control map including M _{2 and} φ ₂ for determining whether to enter the control mode.

FIG. 8 is a schematic configuration diagram of a control suspension VI.

FIG. 9 is an explanatory diagram showing an example of a control effect in the second embodiment.

[Explanation of symbols]

I _{1 to} I ₄ acceleration detecting means II vibration stimulus amount calculating means III control determining means IV driver V driving means VI control suspension

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Rikuo Ishiguro 41-1, Nagakute-cho, Nagakute-cho, Aichi-gun, Aichi Prefecture Toyota Central Research Institute Co., Ltd. No. 1 Toyota Central Research Institute Co., Ltd. (72) Inventor Hiroshi Ishikawa 1-1, Showa-cho, Kariya city, Aichi prefecture Nihon Denso Co., Ltd. (72) Inventor Masayoshi Takeda 1-1-chome, Showa town, Kariya city, Aichi prefecture Co., Ltd. (72) Inventor Takayuki Nagai 1-1-1 Showa-cho, Kariya city, Aichi prefecture Nihon Denso Co., Ltd.

Claims (1)

[Claims] 1. An acceleration detecting means embedded in a seat seat surface and a seat rear surface, for detecting at least one of vertical and longitudinal accelerations acting on an occupant when seated, and an amplitude and a phase of an output of the acceleration detecting means. A vibration stimulus amount calculation unit that calculates a vibration stimulus amount based on the above, and a control unit that determines the vibration stimulus to the occupant based on the amplitude and the phase and changes the suspension system characteristic of the vehicle. Suspension control device.