JPH1148738A - Electric control device for vehicle suspension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease changing of a grounding load relating to a road surface of a tire, so as to hold the good drive stability of a vehicle, in a suspension device for the vehicle. SOLUTION: In electric control for a suspension device comprising a spring, damper and an actuator provided in parallel between a sprung member and an unsprung member, acceleration sensors 51, 52 detect sprung acceleration G2 and unsprung acceleration G1 the sprung acceleration G2 and the unsprung acceleration G1 are input in a CPU 54c, and generation force (F) of the actuator is calculated for decreasing a sum of a product to the sprung acceleration G2 and mass (M2) of the sprung member and a product of the unsprung acceleration G1 and mass (M1) of the unsprung member. In accordance with this generation force (F), a current (I) carried in a coil is calculated, a current carrying pattern (PTN) in accordance with a relative position H is drawn out, by this pattern (PTN), a current carried in coils 37-1, 37-2..., 37-15 is controlled through a drive circuit 55.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a vehicle suspension apparatus having a spring and a damper interposed between a sprung member and a unsprung member of a vehicle. And a vehicle suspension device for electrically controlling an actuator for generating a force for regulating the movement of the sprung member with respect to the unsprung member provided between the sprung member and the ground contact load variation on the road surface of the tire. It relates to an electric control device.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 5-65007
As disclosed in Japanese Unexamined Patent Application Publication No. 4-215510 and Japanese Unexamined Patent Publication No. Hei 4-215510, vibration of the sprung member is suppressed by imparting a damping force to the vertical vibration of the sprung member with respect to the unsprung member, 2. Description of the Related Art A vehicle suspension device designed to improve the steering stability and riding comfort of a vehicle is well known.

[0003]

However, in the above-mentioned conventional device, generally, while the damping force against vibration of the sprung member is increased near the resonance frequency of the sprung member, the damping force in the frequency region other than the resonance frequency is increased. By reducing the damping force of the sprung member against vibration, the ride comfort of the vehicle is improved. Therefore, there is a problem that vibration of the unsprung member near the resonance frequency cannot be suppressed, and a variation in the contact load on the road surface of the tire increases, and when the contact load decreases, the steering stability of the vehicle is impaired.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to address the above-mentioned problems, and has as its object to reduce the variation in the contact load of tires on the road surface, and to maintain good steering stability of the vehicle. An object of the present invention is to provide an electric control device for a suspension device.

[0005] To achieve the above object, the first aspect of the present invention is as follows.
Is applied to a vehicle suspension device in which a spring and a damper are interposed between a sprung member and a unsprung member of a vehicle, and is provided between the sprung member and the unsprung member. An electric control device for a vehicle suspension device having an actuator for generating a force that restricts the movement of the sprung member relative to the unsprung member by being electrically controlled. The sprung acceleration detecting means for detecting, the unsprung acceleration detecting means for detecting the vertical acceleration of the unsprung member, and controlling the actuator based on the detected accelerations of the sprung member and the unsprung member, respectively. Actuate such that the sum of the product of the acceleration of the sprung member and the mass of the sprung member and the product of the detected acceleration of the unsprung member and the product of the mass of the unsprung member are reduced. In the provision and control means for generating a.

Before describing the operation and effect of the first structural feature of the present invention, the outline of the movement of the suspension system will be described using a vehicle single-wheel model shown in FIG.

In this single-wheel vehicle model, a suspension device including a spring SP, a damper DP and an actuator AC provided in parallel is provided between a sprung member (vehicle body) BD and a unsprung member (wheel) WH. Is equipped. Further, the unsprung member WH is in contact with the road surface via the tire TR. Absolute vertical displacements (displacements with respect to absolute space) of the sprung member BD and unsprung member WH are defined as X2 and X1, respectively, and absolute velocities (speeds with respect to absolute space) of the two members BD and WH are defined as V2 and V1, respectively. age,
The vertical accelerations (accelerations in the absolute space) of the two members BD and WH are G2 and G1, respectively, and the two members BD and WH
Are M2 and M1, respectively. Also, the spring S
The spring constant of P, the damping coefficient of the damper DP, and the generated force of the actuator AC are Ks, Cs, and F, respectively. Further, the road surface displacement is X0, and the spring constant of the tire TR is Kt. The displacements X2 and X1, the velocities V2 and V1, the accelerations G2 and G1, and the road surface displacement X0 of the sprung member BD and the unsprung member WH are respectively defined such that the upward direction is positive and the downward direction is negative.
The generated force F of the actuator is positive on the extension side of the suspension device and negative on the contraction side. Also, each spring constant Ks, Kt
And the damping coefficient Cs are positive values.

In this case, the equations of motion of the sprung member BD and the unsprung member WH of the vehicle are expressed by the following equations (1) and (2), respectively.
Represented by

[0009]

M2 · G2 = Ks (X1-X2) + Cs (V1-V2) + F

[0010]

## EQU2 ## M1 / G1 = -Ks (X1-X2) -Cs (V1-V
2) -F + Kt (X0-X1) Here, the variation in the contact load of the tire TR is represented by the fourth term Kt (X0-X1) on the right side of the above equation (2), which represents the force that the tire TR having a spring action receives from the road surface. Can be.

Further, when both sides of the above equations 1 and 2 are added, the following equation 3 is obtained.

[0012]

[Equation 3] M2 · G2 + M1 · G1 = Kt (X0−X1) As can be understood from the above Equation 3, the grounding load fluctuation Kt (X0−X1)
−X1) is represented by the sum of the product of the acceleration G2 of the sprung member and the mass M2 of the sprung member, and the product of the acceleration G1 of the unsprung member and the mass M1 of the unsprung member. Therefore, the first of the present invention
In the configurational characteristic of (1), the control means causes the actuator AC to generate such a force as to reduce the sum, so that it is possible to reduce the variation in the contact load. As a result, the steering stability of the vehicle can be kept good.

A second structural feature is that a sprung differential value detecting means for detecting a differential value of the vertical acceleration of the sprung member, and a differential value of the vertical acceleration of the unsprung member are detected. The unsprung differential value detecting means and the actuator are controlled based on the detected differential values of the accelerations of the sprung member and the unsprung member, and the product of the detected differential value of the acceleration of the sprung member and the mass of the sprung member. And control means for causing the actuator to generate a force that reduces the sum of the detected differential value of the acceleration of the unsprung member and the product of the mass of the unsprung member.

In the case of the feature of the second configuration, the following equation (4) is obtained by differentiating both sides in the above equation (3).

[0015]

M2 · G2 ′ + M1 · G1 ′ = d {Kt (X0−X1)} / dt where G2 ′ is the differential value of the acceleration of the sprung member, and G1 ′ is the differential value of the acceleration of the unsprung member. In the differential values G2 'and G1' of these accelerations, the upward direction is positive and the downward direction is negative.

As can be understood from the above equation (4), the right side d {Kt (X0−X1)} / dt of the equation (4) represents the amount of change in the contact load fluctuation, and the differential value G2 ′ of the acceleration of the sprung member and the spring The differential value G of the product of the mass M2 of the upper member and the acceleration of the unsprung member
It is represented by the sum of 1 'and the product of the mass M1 of the unsprung member. Therefore, in the second structural feature of the present invention, the control means causes the actuator to generate a force such that the sum is reduced, so that the variation in the variation of the grounding load is reduced, and the grounding load is reduced. Fluctuations can be reduced. As a result, the steering stability of the vehicle can be kept good.

Further, a third structural feature is that unsprung acceleration detecting means for detecting the vertical acceleration of the unsprung member, and relative displacement detecting means for detecting a relative displacement of the unsprung member with respect to the sprung member. Relative speed detecting means for detecting the relative speed of the unsprung member with respect to the sprung member, the product of the detected acceleration of the unsprung member and the mass of the unsprung member, and the relative displacement of the detected unsprung member with respect to the sprung member. Control means for controlling the actuator to generate a force equal to the sum of the product of the spring constant of the spring and the product of the detected relative speed of the unsprung member to the sprung member and the damping coefficient of the damper; is there.

In the case of the feature of the third configuration, in the above-mentioned equation 2, when the variation of the contact load Kt (X0-X1) is set to zero, the generated force F of the actuator is expressed by the following equation 5.

[0019]

F = −M 1 · G 1 −Ks (X 1 −X 2) −Cs (V 1 −V 2) As can be understood from the above equation 5, the generated force F of the actuator is the acceleration G 1 of the unsprung member and the unsprung member. Mass M1 of
And the relative displacement of the unsprung member with respect to the sprung member (X
1−X2) and the spring constant Ks of the spring, and the sum of the product of the relative speed (V1−V2) of the unsprung member to the sprung member and the damping coefficient Cs of the damper. Therefore,
In the third structural feature of the present invention, since the control means controls the actuator AC so as to generate a force equal to the sum to the actuator AC, it is possible to reduce the variation in the ground load. As a result, the steering stability of the vehicle can be kept good.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION

A. First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows an electric control device B for electrically controlling an electromagnetic force generating mechanism (actuator) A1 provided in a vehicle suspension device. Is shown by a block diagram.

As shown in FIGS. 3 and 4, the suspension device is disposed between a vehicle body BD constituting a sprung member and a lower arm LA constituting a unsprung member. In addition, a hydraulic damping force generating mechanism (damper) A2 and an air spring mechanism (spring) A3 are provided.

The hydraulic damping force generating mechanism A2 attenuates vibration of the vehicle body BD with respect to the lower arm LA by hydraulic pressure. The outer cylinder 11 and the inner cylinder 12, which are arranged coaxially, and the two cylinders 11, 12 are arranged in the axial direction. And a piston rod 13 assembled to be able to move forward and backward. The outer cylinder 11 has a lower arm L at its lower end.
A is assembled. The inner cylinder 12 is supported on the inner peripheral surface of the outer cylinder 11 at the upper end and the lower end. The piston rod 13 is the outer cylinder 11
, And is attached to the vehicle body BD via a rubber upper support 16 at the upper end thereof.

The inner cylinder 12 is divided into upper and lower chambers R1 and R2 by a main piston 17 which is fixed to the outer peripheral surface of the piston rod 13 and slides on the inner peripheral surface of the inner cylinder 12 in a liquid-tight manner in the axial direction. ing. Upper and lower chambers R1, R
2 is filled with hydraulic fluid (hydraulic oil), and the lower chamber R2 is formed between the outer cylinder 11 and the inner cylinder 12 and is filled in the annular chamber R3 filled with gas.
Communicates at the lower end. The main piston 17 is provided with a fixed orifice (not shown) which connects the upper and lower chambers R1 and R2, and the orifice generates a damping force as the piston rod 13 moves up and down. A sub-piston 18 is fixed to the outer peripheral surface of the piston rod 13 below the main piston 17 with some clearance provided between the sub-piston 18 and the inner peripheral surface of the inner cylinder 12. In the sub-piston 18, a variable orifice (not shown) which connects the upper and lower chambers R1 and R2 is provided.
The opening of the variable orifice is switched by a damping force switching actuator 21 provided at the upper end of the piston rod 13.

The air spring mechanism A3 operates the vehicle body B by air pressure.
D is elastically supported with respect to the lower arm LA,
An upper cylinder 23 and a lower case 24 having a cylindrical shape, and a connecting case 25 for airtightly connecting the two cases 23 and 24 are provided.
An air chamber R4 is formed on the outer circumference of the piston rod 1 and the piston rod 13. An electrically controlled intake and exhaust device (not shown) is connected to the air chamber R4 so that the amount of air in the chamber R4 is adjusted.

The upper case 23 is formed of a flexible resin, and has a rubber upper support 2 on its upper surface.
6 is supported by the vehicle body BD via the support plate 27 and the piston rod 1 is supported via the support plate 27.
3 is hermetically fixed on the outer peripheral surface of the upper end. The lower case 24 is also formed of resin, and is hermetically fixed on the inner peripheral surface of the lower portion on the outer peripheral surface of the cylindrical member 32 welded and fixed on the outer peripheral surface of the outer cylinder 11. The connection case 25 is formed of a diaphragm mainly made of elastic rubber, and is hermetically fixed on an outer peripheral surface of a lower end portion of the upper case 23 by a caulking ring 33 at an upper end thereof. It is hermetically fixed on the upper outer peripheral surface of the lower case 24 by a caulking ring 34.

The electromagnetic force generating mechanism A1 regulates the movement of the vehicle body BD with respect to the lower arm LA by electromagnetic force.
Magnets (permanent magnets) 35, 36 and multiple (for example, 15)
., 37-15. The magnets 35 and 36 are formed in a ring shape, and are fixed on the outer peripheral surface of a support member 38 formed of a nonmagnetic material in a cylindrical shape with the vertical direction as the axial direction. Support member 38
Are erected and fixed to the upper end surface of the lower case 24. The lower end surface of the magnet 35 and the upper end surface of the magnet 36 are magnetized by one magnetic pole (for example, S pole), and the upper end surface of the magnet 35 and the lower end surface of the magnet 36 are magnetized by the other magnetic pole (for example, N pole). An annular rib 41 is fixed on the inner peripheral surface of the upper end portion of the support member 38, and the rib 41 abuts on the outer peripheral surface of the stopper plate 31 on the inner peripheral surface, and the support member 38 is The upper end of the cylinder 11 is supported separately from the outer peripheral surface. In addition, holes 41 a communicating vertically are provided at appropriate plural positions in the circumferential direction of the rib 41, and the upper and lower chambers of the stopper plate 31 are communicated.

The coils 37-1, 37-2 ... 37-1
Numerals 5 are installed at equal intervals along the vertical direction via resin spacers 43 in a cylindrical iron casing 42 having a cylindrical shape with the extending direction of the piston rod 13 as the axial direction. They are arranged facing each other on the outer peripheral surface. Coil 37-1, 37-2 ... 37-15
Are led out of the upper case 23 through the lead wire 37a. Ribs 47 are provided on the inner peripheral surface of the upper case 23 at appropriate locations in the circumferential direction, and support the casing 42 on the inner peripheral surface of the upper case 23 at appropriate locations.

Next, an electric control device B for controlling the electromagnetic force generating mechanism A1 will be described. Note that the electric control device for controlling the hydraulic damping force generation mechanism A2 and the air spring mechanism A3 is not directly related to the present invention, and thus the description thereof is omitted.

As shown in FIG. 2, the electric control unit B includes a sprung acceleration sensor 51, an unsprung acceleration sensor 52, and a vehicle height sensor 53. Sprung acceleration sensor 51
Detects a vertical sprung acceleration G2 with respect to the absolute space of the vehicle body BD. The unsprung acceleration sensor 52 is attached to the lower arm LA and detects the unsprung acceleration G1 in the vertical direction with respect to the absolute space of the lower arm LA. The vehicle height sensor 53 is provided between the vehicle body BD and the lower arm LA, and is connected to the lower arm L of the vehicle body BD.
A relative position (relative height) H with respect to A is detected. In addition,
Each of the sprung acceleration G2 and the unsprung acceleration G1 has a positive upper direction and a negative lower direction. The relative position H is represented by a reference position “0”,
An upward direction is represented by a positive value and a downward direction is represented by a negative value.

Each of these sensors 51 to 53 is connected to a microcomputer 54. The microcomputer 54 includes an input interface 54b, a CPU 54c, a ROM 54 connected to a bus 54a, respectively.
d, a RAM 54e and an output interface 54f. The input interface 54b is connected to each of the sensors 51 to
A detection signal representing the sprung acceleration G2, unsprung acceleration G1, and relative position H is input from each of the sensors 51 to 53. The CPU 54c repeatedly executes a program corresponding to the flowchart shown in FIG.
-2 ... Controls energization of 37-15.

The ROM 54d stores the above-mentioned program and a plurality of (for example, nine types) of plural energizing patterns PTN corresponding to a plurality of (for example, nine) relative positions H in FIG.
The energization pattern table shown in FIG. Each energization pattern PTN includes a data group indicating energization, non-energization, and energization direction of the coils 37-1, 37-2,..., 37-15 in order to apply an electromagnetic force to the vehicle body BD. In FIG. 6, "1" indicates a coil which is energized in the forward direction, "0" indicates a coil which is energized in the reverse direction, and other than those indicate coils which are not energized. The RAM 54e temporarily stores data necessary for executing the program. The output interface 54f supplies the drive pattern 55
Is output to

As shown in FIG. 7, the drive circuit 55 includes current supply control circuits 55-1, 55-2,... 55-15 corresponding to the coils 37-1, 37-2,.
It has. Each energization control circuit 55-1, 55-2 ...
55-15 receives a control signal indicating the energization pattern PTN and the energization current I from the microcomputer 54 to control energization and non-energization of the coils 37-1, 37-2,. The direction and amount of energization are controlled. Regarding the direction of energization, the direction of the solid arrow in the drawing is the forward direction, and the direction of the broken line in the drawing is the reverse direction.

Next, the operation of the first embodiment configured as described above will be described. The control of the damping force by the hydraulic damping force generating mechanism A2 and the adjustment of the vehicle height by the air spring mechanism A3 are directly related to the present invention. Therefore, the description of those operations will be omitted, and only the control operation of the electromagnetic force by the electromagnetic force generation mechanism A1 will be described.

When an ignition switch (not shown) is turned on, the CPU 54c repeatedly executes the program shown in FIG. 5 every predetermined short time. The execution of this program is started in step 100, and the CPU 54c determines in step 102 the sprung acceleration G2, unsprung acceleration G1, and relative position H from the sprung acceleration sensor 51, unsprung acceleration sensor 52, and vehicle height sensor 53. Are detected, and in step 104, the product of the input sprung acceleration G2 and a predetermined control gain constant a2 is multiplied by the input unsprung acceleration G1 and a predetermined control gain constant a1. Then, the generated force F of the actuator shown in the following equation 6 is calculated by adding

[0035]

[Mathematical formula-see original document] F = a1 * G1 + a2 * G2 The generated force F is positive on the extension side and negative on the contraction side. The control gain constant a1 is a predetermined positive value and is equal to the mass M1 of the unsprung member. Control gain constant a2
Is a predetermined negative value, and its absolute value | a2 |
Is equal to the mass M2 of the unsprung member.

In step 106, an energization pattern PTN corresponding to the input relative position H is derived with reference to the energization pattern table (FIG. 6) provided in the ROM 54d. Next, at step 108, the calculated force F
Is multiplied by a predetermined proportionality coefficient K to calculate a conduction current I (= K · F). And step 11
At 0, a control signal indicating the derived energizing pattern PTN and the calculated energizing current I is output to the drive circuit 55, and the execution of this program is temporarily terminated at step 112. Thereafter, the CPU 54c repeatedly executes the program of FIG. 5 every predetermined short time.

Here, Equation 6 will be described.
Since the absolute values | a1 | and | a2 | of the constants a1 and a2 are respectively equal to the masses M1 and M2 of the unsprung member and the sprung member, respectively, the first term a1 · G1 and the second term a2 of Equation 6 above. When G2 is defined as the component forces F1 and F2 acting on the unsprung member and the sprung member, and the combined force of the respective component forces F1 and F2 is considered as the generated force F, the above equation 6 is expressed as the following equation 7 Is done.

[0038]

In this case, the constant a1 is a predetermined positive value, and the generated force F is positive on the extension side of the suspension device, and the unsprung acceleration G1 is the following: F = F1 + F2 = a1 · G1 + a2 · G2 Since the upward direction is positive, the component force F1 is a force in the opposite direction to the forces M1 and G1 acting on the unsprung member LA from the viewpoint of the unsprung member LA.
It acts to prevent the same force M1 · G1. Further, the constant a2 is a predetermined negative value, the generated force F is positive on the extension side of the suspension device, and the sprung acceleration G2 is positive in the upward direction. From the viewpoint of the upper member BD, the force acting on the sprung member BD is opposite to the force M2 · G2, and the same force M
It acts to block 2.G2. As a result, the generated force F expressed by Equation 6 is equal to the sprung acceleration G2
And the product of the mass M2 of the unsprung member and the product of the unsprung acceleration G1 and the mass M1 of the unsprung member.

Returning to the description of the above operation, in the drive circuit 55 to which the control signal indicating the power supply pattern PTN and the calculated power supply current I is inputted, each of the power supply control circuits 55-1, 55-2,. 55-15 is the coil 37-
1, 37-2..., 37-15
A current equal to the current I flows through the coil specified by the TN. Here, the energizing direction of each coil is determined in the forward or reverse direction depending on whether the energizing current I is positive or negative. When the energizing current I is positive (the generated force F extends), the energizing direction of the coil is determined by the energizing pattern PTN shown in FIG. 6, and when the energizing current I is negative (the generated force F contracts), The energization direction of the coil is determined by a pattern in which “1” and “0” of the energization pattern PTN are inverted to “0” and “1”, respectively.

In this case, when the current I is positive,
As shown in (A), the coils 37-1, 37-2,.
Of the coils 37-15, a coil substantially opposed to the center of the magnets 35 and 36 and two coils on both sides thereof (37-7 to 3-7)
7-9) is energized in the opposite direction, and the coils substantially opposing both ends of the magnets 35 and 36 and the two coils (3
7-3 to 37-5, 37-11 to 37-13) are energized in the forward direction. That is, in the coils 37-7 to 37-9, a current flows in the front direction from the back side of the drawing on the left side, and a current flows in the back direction from the front side of the drawing on the right side. Also, the coils 37-3 to 37-5,
In each of 37-11 to 37-13, a current flows from the front side to the back side on the left side, and a current flows from the back side to the front side on the right side.

The coils 37-3 to 37-5 receive the magnetic flux from the inside to the outside of the coil formed by the magnet 35. Therefore, an upward electromagnetic force acts on each of the coils 37-3 to 37-5. Similarly to these coils, each of the other energized coils 37-7 to 37-
An upward electromagnetic force also acts on 9, 37-11 to 37-13 by the magnetic field formed by the magnets 35 and 36, respectively. As a result, the vehicle body BD receives an upward force, and the lower arm LA receives a downward force as a reaction.
Therefore, these energized coils and magnets 35,
The electromagnetic force by 36 acts to urge the vehicle body BD against the lower arm LA toward the extension side of the suspension device.

On the other hand, when the current I is negative, the coils 37-1, 37-2,..., 37-1, as shown in FIG.
5, among the coils substantially facing the center of the magnets 35 and 36 and the two coils on both sides thereof (37-7 to 37-9)
Are energized in the forward direction, and the coils substantially opposing both ends of the magnets 35 and 36 and the two coils on both sides thereof (37-3 to 37-3).
37-5, 37-11 to 37-13) are energized in the reverse direction. That is, a current flows through the coils 37-7 to 37-9 from the front to the back of the drawing on the left side, and a current flows from the back of the drawing to the front side on the right side. Also, the coils 37-3 to 37-5, 37-
On the left side, currents flow in the front direction from the back side of the paper, and on the right side, currents flow in the back direction from the front side on the paper side.

The coils 37-3 to 37-5 receive a magnetic flux from the inside to the outside of the coil formed by the magnet 35. Therefore, a downward electromagnetic force acts on each of the coils 37-3 to 37-5. Similarly to these coils, each of the other energized coils 37-7 to 37-
A downward electromagnetic force also acts on 9, 37-11 to 37-13 by the magnetic field formed by the magnets 35 and 36, respectively. As a result, the vehicle body BD receives a downward force, and the lower arm LA receives an upward force as a reaction.
Therefore, these energized coils and magnets 35,
The electromagnetic force by 36 acts to urge the vehicle body BD toward the contraction side of the suspension device with respect to the lower arm LA. The control of the vibration of the sprung member by the electromagnetic force as described above is performed in a manner superimposed on the vibration damping control by the hydraulic damping force generating mechanism A2.

The above operation is specifically described in correspondence with the vertical movement of the unsprung member LA and the sprung member BD. For example, the unsprung acceleration G1 and the sprung acceleration G2 are respectively upward (that is, G1 is In the case of positive) and downward (that is, G2 is negative), the component force F1 is downwardly directed to the unsprung member LA.
, And the component force F2 acts upward on the sprung member BD. Therefore, a generated force F is generated in the actuator AC on the extension side of the suspension device.

When the unsprung acceleration G1 and the unsprung acceleration G2 are downward (that is, G1 is negative) and upward (that is, G2 is positive), the component force F1 rises upward and the unsprung member LA
And the component force F2 acts downward on the sprung member BD. Therefore, the generated force F is generated in the actuator AC on the contraction side of the suspension device.

When the unsprung acceleration G1 and the unsprung acceleration G2 are upward (G1 and G2 are positive), the component force F
1 acts downward on the unsprung member LA, and the component force F2 acts downward on the sprung member BD. In this case, the actuator AC has the absolute values | F1 |, | F2 of the two component forces F1, F2.
The generated force F is generated according to the component force of |. When the component force having a large absolute value is the component force F1, the generated force F is generated on the extension side of the suspension device, and when the component force is the component force F2, the generated force F is generated on the contraction side of the suspension device.

When the unsprung acceleration G1 and the unsprung acceleration G2 are downward (G1 and G2 are each negative), the component force F
1 acts upward on the unsprung member LA, and the component force F2 acts upward on the sprung member BD. In this case, the actuator AC has the absolute values | F1 |, | F2 of the two component forces F1, F2.
The generated force F is generated according to the component force of |. When the component force having a large absolute value is the component force F1, the generated force F is generated on the contraction side of the suspension device, and when the component force is the component force F2, the generated force F is generated on the extension side of the suspension device.

As can be understood from the above description of operation, according to the first embodiment, the generation represented by the sum of the product of the sprung acceleration G2 and the constant a2 and the product of the unsprung acceleration G1 and the constant a1. By generating the force F in the electromagnetic force generator A1 as an electromagnetic force, the product of the acceleration G2 of the sprung member and the mass M2 of the sprung member and the product of the acceleration G1 of the unsprung member and the mass M1 of the unsprung member are obtained. And the variation of the tire contact load can be reduced. As a result, the steering stability of the vehicle is kept good.

Next, a modification of the first embodiment configured as described above will be described. In this modification, the above equation 6
Instead of (F = a 1 · G 1 + a 2 · G 2), the generated force F is calculated by the following equation (8).

[0050]

[Formula 8] F = k1 · a1 · G1 + k2 · a2 · G2 Here, k1 and k2 are weighting constants, and the identification numbers k1 and k2 are controlled by weighting the unsprung member or the sprung member. To determine. Also, constants k1 and k2
Are positive.

For example, in the case where the sprung member rises greatly while the vehicle is traveling on a low-frequency road surface such as a largely undulating road surface, the constant k1 is set to “1” and the constant k2 is set to “0. 5 ", the generated force F is weighted to control the vibration of the sprung member near the resonance frequency of the member.
Can be generated in the actuator AC. In the case where the unsprung member flaps while the vehicle is traveling on a high-frequency road surface such as a cobblestone road surface,
If the constant k1 is set to "0.5" and the constant k2 is set to "1", the actuator AC can generate the generated force F with a weight for controlling the vibration of the unsprung member near the resonance frequency. . As a result, according to this modified example, it becomes possible to control the actuator AC according to the frequency range of the input received from the road surface of the vehicle, and it is possible to reduce the variation in the contact load.

B. Second Embodiment Next, a second embodiment of the present invention will be described. In the second embodiment, the program shown in FIG. 9 is stored in the ROM 54d instead of the program shown in FIG. 5, and the CPU 54c repeatedly executes the program every predetermined short time. Other configurations are the same as those in the above embodiment.

The program of FIG. 9 is different from the program of the above-described embodiment in that the processing of step 104 is replaced with step 120.
And 122 are adopted. In step 120, the input unsprung acceleration G1 and the sprung acceleration G2 are differentiated to obtain a differential value G1 'of the unsprung acceleration and a differential value G2' of the sprung acceleration.
Is calculated. Note that these two differential values G1 'and G2' are
The upward direction is represented by positive and the downward direction is represented by negative. In step 122, the differential value G2 'of the calculated sprung acceleration and a predetermined control gain constant b2
Is added to the product of the calculated differential value G1 'of unsprung acceleration and a predetermined control gain constant b1 to generate a force F
Is calculated.

[0054]

[Mathematical formula-see original document] F = b1.G1 '+ b2.G2' The generated force F is positive on the extension side and negative on the contraction side. The control gain constant b1 is a predetermined positive value and is equal to the mass M1 of the unsprung member. Control gain constant b2
Is a predetermined negative value, and its absolute value | b2 |
Is equal to the mass M2 of the unsprung member. Other processes are the same as those in the first embodiment.

As a result, according to the second embodiment, the sum of the product of the differential value G2 'of the sprung acceleration and the constant b2 and the product of the differential value G1' of the unsprung acceleration and the constant b1 is represented. By generating the generated force F as an electromagnetic force in the electromagnetic force generator A1, the product of the differential value G2 'of the sprung acceleration and the mass M2 of the sprung member, the differential value G1' of the unsprung acceleration, and the unsprung acceleration The sum of the product and the product of the mass M1 of the members is reduced, and the amount of change in the tire contact load variation can be reduced, that is, the tire contact load variation can be reduced. as a result,
The steering stability of the vehicle is kept good.

Next, a modification of the second embodiment configured as described above will be described. In this modification, the above equation 9
Instead of (F = b1, G1 '+ b2, G2'),
The generated force F is calculated based on 0.

[0057]

F = k1 · b1 · G1 ′ + k2 · b2 · G2 ′ Note that k1 and k2 are weighting constants, and both constants k1 and k2 are weighted with respect to either the unsprung member or the sprung member. Decide what to control. Also, constants k1 and k2
Are positive.

Therefore, according to this modification, the same operation and effect as those of the above-described modification of the first embodiment can be obtained.

C. Third Embodiment Next, a third embodiment of the present invention will be described. In the third embodiment, the program shown in FIG. 10 is stored in the ROM 54d instead of the program shown in FIG. 5, and the CPU 54c repeatedly executes the program at predetermined short intervals. Other configurations are the same as those in the above embodiment.

The program of FIG. 10 employs the processing of steps 130 to 134 instead of the processing of steps 102 and 104 of the program of the above embodiment. In step 130, the unsprung acceleration sensor 52
And a detection signal representing the unsprung acceleration G1 and the relative position H from the vehicle height sensor 53, respectively, and in step 132, the input relative position H is differentiated to obtain the unsprung member LA with respect to the sprung member BD. Calculate the relative speed V. Note that the relative speed V is represented by a positive value in the upward direction and a negative value in the downward direction.

Next, at step 134, the product of the inputted unsprung acceleration G1, the control gain constant c1 and "-1" and the product of the inputted relative displacement H, the control gain constant c2 and "-1". And the product of the calculated relative speed V, control gain constant c3, and "-1" to calculate the generated force F of the actuator shown in the following equation (11).

[0062]

[Mathematical formula-see original document] F = -c1, G1-c2, H-c3, V The generated force F is positive on the extension side and negative on the contraction side. The control gain constant c1 is a predetermined positive value and is equal to the mass M1 of the unsprung member. Control gain constant c2
Is a predetermined positive value and is equal to the spring constant Ks of the air spring mechanism A3. The control gain constant c3 is a predetermined positive value and is equal to the damping coefficient Cs of the hydraulic damping force generating mechanism A2. Other processes are the same as those in the first embodiment.

As a result, according to the third embodiment, the product of the unsprung acceleration G1, the control gain constant c1 and "-1", the product of the relative displacement H, the control gain constant c2 and "-1", By causing the electromagnetic force generator A1 to generate a force F equal to the sum of the product of the relative speed V, the control gain constant c3, and the product of "-1" as the electromagnetic force, the variation in the ground contact load of the tire can be made zero. . As a result, the steering stability of the vehicle is kept good.

Note that, instead of the electromagnetic force generator A1 in the above-described embodiments and modifications, a responsive hydraulic active suspension device or a variable damping force shock absorber is provided between the sprung member BD and the unsprung member LA. Thereby, the movement of the sprung member BD relative to the unsprung member LA may be restricted.

[Brief description of the drawings]

FIG. 1 is a diagram of a vehicle single-wheel model.

FIG. 2 is a block diagram of an electric control device for controlling an electromagnetic force generating mechanism of the suspension device according to the embodiment of the present invention.

FIG. 3 is a partially cutaway view showing the entire suspension device.

FIG. 4 is an enlarged view of a central portion of the suspension device of FIG.

FIG. 5 is a flowchart of a program executed by a CPU in FIG. 2;

FIG. 6 is a memory map showing stored contents of an energization pattern table provided in a ROM of FIG. 2;

7 is an electric circuit diagram showing a part of the drive circuit of FIG. 2 in detail.

FIG. 8 is an operation explanatory diagram for explaining a state of generation of an electromagnetic force by the energization pattern.

FIG. 9 relates to a first modification of the embodiment,
4 is a flowchart of a program executed by a PU.

FIG. 10 is a flowchart of a program executed by a CPU in FIG. 2 according to a second modification of the embodiment.

[Explanation of symbols]

A1: an electromagnetic force generating mechanism, A2: a hydraulic damping force generating mechanism,
A3: air spring mechanism, B: electric control device, BD: vehicle body,
LA: lower arm, 35, 36: magnet, 37-1, 37
-2 ... 37-15 ... coil, 51 ... sprung acceleration sensor, 52 ... unsprung acceleration sensor, 53 ... vehicle height sensor,
54: microcomputer, 54c: CPU, 54d
... ROM, 55 ... Drive circuit.

Claims (3)

[Claims] The present invention is applied to a vehicle suspension device in which a spring and a damper are interposed between a sprung member and a unsprung member of a vehicle, and is provided between the sprung member and the unsprung member. Control device for a vehicle suspension device provided with an actuator for generating a force for controlling the movement of the sprung member relative to the unsprung member in a controlled manner, wherein the vertical acceleration of the sprung member is detected. Sprung acceleration detecting means, unsprung acceleration detecting means for detecting vertical acceleration of the unsprung member, controlling the actuator based on the detected accelerations of the sprung member and the unsprung member, and detecting the same. A force that reduces the sum of the product of the acceleration of the sprung member and the mass of the sprung member and the product of the detected product of the acceleration of the unsprung member and the mass of the unsprung member. Electric control apparatus for a vehicle suspension system, characterized in that a control means for generating the Chueta. 2. A suspension apparatus for a vehicle comprising a spring and a damper interposed between a sprung member and a unsprung member of a vehicle, wherein the electric device is provided between the sprung member and the unsprung member. Control device for a vehicle suspension device provided with an actuator for generating a force for controlling the movement of the sprung member relative to the unsprung member, the differential value of the vertical acceleration of the sprung member A sprung differential value detecting means for detecting the differential value of the vertical acceleration of the unsprung member, and an unsprung differential value detecting means for detecting a differential value of the acceleration in the vertical direction of the unsprung member. Controlling the actuator based on the product of the differential value of the detected sprung member acceleration and the mass of the sprung member, and the differential value of the detected sprung member acceleration and the detected unsprung member acceleration. The amount of the electric control apparatus for a vehicle suspension system, characterized in that the force of the sum is small provided a control means for generating the same actuator and the product. 3. A suspension apparatus for a vehicle having a spring and a damper interposed between a sprung member and a unsprung member of a vehicle, and an electric device provided between the sprung member and the unsprung member. Control device for a vehicle suspension device provided with an actuator for generating a force for controlling the movement of the sprung member relative to the unsprung member in a controlled manner, wherein the vertical acceleration of the unsprung member is detected. Unsprung acceleration detecting means, relative displacement detecting means for detecting a relative displacement of the unsprung member with respect to the sprung member, relative speed detecting means for detecting a relative speed of the unsprung member with respect to the sprung member, The product of the acceleration of the member and the mass of the unsprung member; the product of the detected relative displacement of the unsprung member with respect to the sprung member and the spring constant of the spring; And a control means for controlling the actuator so as to generate a force equal to the sum of the product of the relative speed of the unsprung member to the sprung member and the damping coefficient of the damper. Electrical control device for.