JPH0665522B2 - Active suspension for vehicles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a suspension of a vehicle such as an automobile, and more particularly to an active suspension.

2. Description of the Related Art Conventionally, suspensions of vehicles such as automobiles have generally been designed to support the weight of the vehicle body and to support the weight of the vehicle body in order to reduce the impact transmitted to the vehicle body from the road surface and transmitted to the vehicle body. Suspension springs are incorporated which absorb the impact as potential energy due to elastic deformation by allowing relative displacement of the vehicle body with respect to each other mainly in the vertical direction. The load on the suspension spring, that is, the load acting between each wheel and the vehicle body is mechanically determined by the weight of the vehicle body (on the spring) and the relative positional relationship of each wheel with respect to the vehicle body, and varies depending on the running state of the vehicle. To do. For example, when the vehicle is turning or when suddenly accelerating or decelerating, the vehicle body is biased relative to the wheels by the inertial force acting on it,
Due to this, the load acting between each wheel and the vehicle body is changed, and as a result, the elastic deformation amount of the suspension spring changes, causing unintentional shaking and posture change of the vehicle body such as a roll and nose type.

Problems to be Solved by the Invention In order to secure the steering stability of the vehicle by reducing the shake and posture change of the vehicle body, a stabilizer is incorporated in the suspension of the vehicle such as an automobile, and the spring characteristics of the suspension spring are progressive. Spring characteristics are set. However, since these means only passively reduce the shake and posture change of the vehicle body, the shake and posture change of the vehicle body cannot be sufficiently reduced by the above-mentioned means. Further, in order to improve the steering stability while ensuring a good riding comfort of the vehicle by the means as described above, it is necessary to perform complicated calculations and design of the suspension mechanism, and the delicate suspension spring and shock absorber. Tuning is required.

As one of active vibration damping methods and devices for vehicles such as automobiles, Japanese Patent Laid-Open No. 54-55913 discloses that a vehicle body mass is provided on a vehicle mass via a force-generating servo cylinder operated by a valve. In the vehicle, the valve is an electro-hydraulic valve driven by electro-hydraulic, and therefore, as a measurement signal, the mutual distance δ (t) between the vehicle body and the wheels, and the relative movement between the vehicle body and the wheels are used. Method of active vibration damping in wheeled wheels, especially in motor vehicle wheels, characterized by using relative velocity δ '(t) in the servo cylinder and pressure difference Δp (t) in the servo cylinder, and implementation of this method A device for use in is disclosed. However, since this method and device presuppose that relative displacement occurs between the vehicle body and the wheels,
With this method and device it is not possible to maintain the body posture substantially constant.

In view of the above problems in the conventional suspension of a vehicle such as an automobile, the inventor of the present application prevents the vehicle body from significantly shaking even during turning of the vehicle, and maintains the vehicle body posture substantially constant. As a result, in order to provide an improved active suspension for a vehicle so as to improve riding comfort and steering stability during turning of the vehicle, Japanese Patent Application No. 60-21523 filed by the same applicant as the applicant of the present application.
A plurality of actuators provided between each wheel of the vehicle and the vehicle body and supporting the vehicle body with respect to the corresponding wheels, and a vehicle width direction acceleration detection for detecting an acceleration of the vehicle body in the vehicle width direction. And a vehicle width direction acceleration signal from the acceleration detection means, and calculates the amount of change in the load acting between each wheel and the vehicle body due to the acceleration of the vehicle body in the vehicle width direction from the acceleration signal. An active suspension for a vehicle including an arithmetic control unit that controls each actuator based on the calculation result and increases or decreases a force acting between the corresponding wheel and the vehicle body via the actuator, and each wheel of the vehicle and the vehicle body. A plurality of actuators that are provided between the two to support the vehicle body with respect to the corresponding wheels, and vehicle width direction acceleration detection means that detects acceleration of the vehicle body in the vehicle width direction; A vehicle width direction acceleration signal is input from the acceleration detection means, and a variation amount of a load acting between each wheel and the vehicle body due to acceleration in the vehicle width direction of the vehicle body is calculated from the acceleration signal, and the calculated result is obtained. Based on a plurality of load detecting means for detecting the force supported by each actuator, including an arithmetic and control unit that controls each actuator based on the actuator and increases or decreases the force acting between the corresponding wheel and the vehicle body via the actuator. The detected actual fluctuation amount of the force supported by each actuator is compared with the fluctuation amount of the load acting between the wheels and the vehicle body calculated by the arithmetic and control unit, and the deviation between them is made zero. We have proposed an active suspension for vehicles that is configured to be feedback controlled.

In general, in vehicles such as automobiles, in order to improve the maneuverability in the low-speed range, to improve the steering stability in the normal range, and to improve the straight running performance in the high-speed range. It is preferable that the vehicle steer characteristic is an oversteer characteristic in a low speed traveling range, a neutral steer characteristic in a normal traveling range, and an understeer characteristic in a high speed traveling range. However, in the vehicle active suspension according to the above-mentioned proposal, the force acting between the wheel and the vehicle body is increased or decreased at a constant ratio between the front wheel and the rear wheel. Steer characteristics cannot be properly controlled according to the traveling speed.

In view of the above-mentioned problems in the conventional suspension of a vehicle such as an automobile and the above-described active suspension for a vehicle, the present invention does not significantly shake the vehicle body even when the vehicle turns, and The posture is kept substantially constant, so not only is it excellent in riding comfort and steering stability during turning of the vehicle, but also maneuverability in low-speed driving range and steering stability in normal driving range. It is an object of the present invention to provide an improved active suspension for a vehicle, which is excellent in running performance and straight running performance in a high speed running range.

Further, the present invention is excellent not only in turning the vehicle but also in riding comfort and steering stability when the vehicle receives a side wind,
Moreover, it is an object of the present invention to provide an improved active suspension for a vehicle, which is excellent in steerability in a low speed range, steering stability in a normal range, and straight running performance in a high speed range.

According to the present invention, a plurality of actuators provided between each wheel of a vehicle and a vehicle body for supporting the vehicle body with respect to the corresponding wheels are provided. Vehicle width direction acceleration detection means for detecting the vehicle body width direction acceleration, vehicle speed detection means for detecting the traveling speed of the vehicle, and vehicle width direction acceleration signals and vehicle speed signals from the acceleration detection means and the vehicle speed detection means, respectively. Is input, and the total variation amount of the load acting between each of the front and rear wheels and the vehicle body due to the acceleration in the vehicle width direction of the vehicle body is calculated from the acceleration signal, and the calculation result is calculated by the vehicle speed signal. Distribution calculation is performed for the front and rear wheels at a ratio according to the vehicle speed shown, and each actuator is controlled based on the calculation result to increase the force acting between the corresponding wheel and the vehicle body via the actuator. A vehicle active suspension including a calculation control device for reducing the vehicle body, a plurality of actuators provided between each wheel of the vehicle and the vehicle body for supporting the vehicle body with respect to the corresponding wheels, and acceleration in the vehicle width direction of the vehicle body A vehicle width direction acceleration detection means, a vehicle speed detection means for detecting a traveling speed of the vehicle, a vehicle width direction acceleration signal and a vehicle speed signal respectively inputted from the acceleration detection means and the vehicle speed detection means. The total fluctuation amount of the load acting between each one-side front and rear wheel and the vehicle body due to the acceleration of the vehicle body in the vehicle width direction is calculated, and the calculation result is set to a ratio according to the vehicle speed indicated by the vehicle speed signal. Based on the calculation result, the actuators are controlled based on the calculation result to increase or decrease the force acting between the corresponding wheel and the vehicle body via the actuators. An arithmetic and control unit, and the actual fluctuation amount of the force supported by each actuator detected by a plurality of load detection means for detecting the force supported by each actuator, and each wheel calculated by the arithmetic and control unit. An active suspension for a vehicle that is configured to perform feedback control so as to compare the variation amount of the load acting between the vehicle body and the deviation between the two, and that is provided between each vehicle wheel and the vehicle body. A plurality of actuators for supporting the vehicle body with respect to corresponding wheels, a vehicle width direction acceleration detecting means for detecting acceleration of the vehicle body in the vehicle width direction, and a roll angular acceleration detection for detecting angular acceleration of the vehicle body in the roll direction. Means, vehicle speed detection means for detecting the traveling speed of the vehicle, the vehicle width direction acceleration detection means, the roll angular acceleration detection means, and the vehicle The vehicle width direction acceleration signal, the roll angular acceleration signal, and the vehicle speed signal are input from the detection means, and the vehicle width direction acceleration signal and the roll angular acceleration signal are input to determine whether the vehicle is turning or the vehicle receives a crosswind. If it is determined that the vehicle is turning, the distance between the front and rear wheels on one side caused by the acceleration in the vehicle width direction of the vehicle body and the vehicle body is determined from the vehicle width direction acceleration signal. When the total variation amount of the load acting on the vehicle is calculated and it is determined that the vehicle receives a crosswind, the front and rear wheels on one side due to the acceleration of the vehicle body in the roll direction are determined from the roll angular acceleration signal. The total variation amount of the load acting on the vehicle body is calculated, the calculation result is distributed to the front and rear wheels at a ratio according to the vehicle speed indicated by the vehicle speed signal, and each actuator is controlled based on the calculation result. Shichi acti An active suspension for a vehicle including an arithmetic and control unit that increases and decreases a force acting between the corresponding wheel and the vehicle body via a tuner, and a corresponding wheel provided between each wheel of the vehicle and the vehicle body A plurality of actuators for supporting the vehicle body; a vehicle width direction acceleration detecting means for detecting an acceleration of the vehicle body in a vehicle width direction; a roll angular acceleration detecting means for detecting an angular acceleration of the vehicle body in a roll direction; Vehicle speed detecting means for detecting the traveling speed of
A vehicle width direction acceleration signal, a roll angular acceleration signal and a vehicle speed signal are respectively input from the vehicle width direction acceleration detection means, the roll angular acceleration detection means and the vehicle speed detection means, and the vehicle width direction acceleration signal and the roll angular velocity signal are input. When it is determined whether the vehicle is turning or whether the vehicle receives a crosswind, and when it is determined that the vehicle is turning, the vehicle width direction acceleration signal is used to accelerate the vehicle body in the vehicle width direction from the vehicle width direction acceleration signal. The total variation amount of the load acting between each one-side front and rear wheel and the vehicle body is calculated, and when it is determined that the vehicle has received a side wind, the roll angular acceleration signal of the vehicle body is used. The total fluctuation amount of the load acting between each one-side front and rear wheel and the vehicle body due to the acceleration in the roll direction is calculated, and the calculation result is distributed to the front and rear wheels at a ratio according to the vehicle speed indicated by the vehicle speed signal. And a calculation control device that controls each actuator based on the calculation result and increases or decreases the force acting between the corresponding wheel and the vehicle body via the actuator, and detects the force supported by each actuator. The actual variation amount of the force supported by each actuator detected by the plurality of load detection means is compared with the variation amount of the load acting between each wheel and the vehicle body calculated by the arithmetic and control unit. This is achieved by an active suspension for a vehicle that is configured to be feedback-controlled so that the difference between the two is zero.

Actions and Effects of the Invention As described above, when the vehicle turns, the vehicle body is urged relative to the wheels by the centrifugal force acting on the vehicle body, and as a result, the load acting between each wheel and the vehicle body is changed. But
In that case, the variation amount of the load is proportional to the centrifugal force acting on the vehicle body, that is, the magnitude of the acceleration of the vehicle body, and the increase or decrease of the load is determined by the direction of the acceleration. Therefore, by detecting the acceleration of the vehicle body, it is possible to know the variation amount and increase / decrease of the load acting between each wheel and the vehicle body.

According to the present invention, the vehicle width direction acceleration detecting means detects the vehicle width direction acceleration of the vehicle body, and the arithmetic and control unit determines the vehicle width direction acceleration of the vehicle body from the vehicle width direction acceleration signal from the vehicle width direction acceleration detecting means. The total fluctuation amount of the load acting between each one-side front and rear wheel and the vehicle body is calculated, and the calculation result is distributed to the front and rear wheels at a ratio according to the vehicle speed, and each wheel and the vehicle body are calculated based on the calculation result. A plurality of actuators that are provided between the wheels and the corresponding wheels and that support the vehicle body are controlled, and the force that acts between the corresponding wheels and the vehicle body via the actuators is increased or decreased. It is possible to prevent the swaying of the vehicle body and the change in the posture caused by the action of the vehicle from becoming large in advance, which makes it possible to maintain the vehicle body posture in an appropriate state even when the vehicle turns. Good ride comfort and steering stability can be obtained, and by appropriately changing the ratio according to the traveling speed of the vehicle, the steer characteristic of the vehicle can be oversteered and neutralized according to the traveling speed of the vehicle. The steer characteristic and the understeer characteristic can be appropriately changed.

According to the above-described first and third configurations of the present invention, between the magnitude of the acceleration (centrifugal force) in the vehicle width direction of the vehicle body and the resulting variation in the load acting between each wheel and the vehicle body. Because of the proportional relationship, the arithmetic and control unit receives the vehicle width direction acceleration signal from the vehicle width direction acceleration detecting means, and the vehicle body width direction acceleration signal from the acceleration signal is applied between each one-side front-rear wheel and the vehicle body caused by the vehicle body width direction acceleration. The total amount of variation of the load acting on the actuator is calculated, each actuator is controlled in an open loop system based on the calculation result, and the force acting between the corresponding wheel and the vehicle body via the actuator is increased or decreased. There is.

According to the above-described second and fourth configurations of the present invention, each actuator is supported by the active suspension of the present invention so that each actuator can be controlled more appropriately according to the acceleration in the vehicle width direction acting on the vehicle body. The actual fluctuation amount of the force supported by each actuator detected by the plurality of load detecting means for detecting the force to be applied and the fluctuation amount of the load acting between each wheel and the vehicle body calculated by the arithmetic and control unit. In comparison, the feedback control is performed so as to reduce the deviation between the two, so that the posture of the vehicle body and the steer characteristic of the vehicle can be controlled more accurately.

Generally, the vehicle body rolls both when the vehicle turns and when the vehicle receives a crosswind, but the direction of acceleration in the vehicle width direction and the direction of roll angular acceleration of the vehicle body seen above the center of gravity are When the vehicle turns, the directions are opposite to each other, whereas when the vehicle receives a cross wind, the directions are the same. According to the above-mentioned third and fourth configurations of the present invention, the vehicle width direction acceleration detecting means detects the vehicle width direction acceleration of the vehicle body, and the roll angular acceleration detecting means detects the vehicle body roll direction angular acceleration. The arithmetic control device determines whether the vehicle is turning or receives a crosswind from the vehicle width direction acceleration signal from the vehicle width direction acceleration detecting means and the roll angular acceleration signal from the roll angular acceleration detecting means, and the vehicle is turning. If the determination is made that the total variation of the load acting between the front and rear wheels on one side and the vehicle body due to the acceleration of the vehicle body in the vehicle width direction is calculated, it is determined that the vehicle has received a crosswind. If the determination is made, the total fluctuation amount of the load acting between each front and rear wheel and the vehicle body due to the acceleration in the roll direction of the vehicle body is calculated, and the calculation result is calculated at a ratio according to the vehicle speed. The calculation is distributed to the front and rear wheels. Each actuator is controlled based on the calculation result, and the force acting between the corresponding wheel and the vehicle body is increased or decreased via the actuator. Therefore, not only when the vehicle turns, but also when the vehicle receives a crosswind. The posture of the vehicle body can be maintained in an appropriate state, whereby good riding comfort and steering stability of the vehicle can be ensured, and by appropriately changing the ratio according to the vehicle speed, the vehicle can be It is possible to appropriately change the steer characteristic of No. 1 to the oversteer characteristic, the neutral steer characteristic, and the understeer characteristic according to the traveling speed.

According to one detailed characteristic of the present invention, in any of the above configurations, the arithmetic and control unit is arranged such that when the vehicle speed is less than a first predetermined value such as 20 km / h, the rear wheel side is more than the front wheel side. The calculation result is distributed and calculated so as to increase the distribution amount. With such a configuration, the load sharing amount on the rear wheel side becomes larger than that on the front wheel side, so that the steer characteristic of the vehicle becomes the over steer characteristic, which can improve the steerability in the low speed traveling range of the vehicle. it can.

According to another detailed feature of the present invention, in any of the above configurations, the arithmetic and control unit has a vehicle speed of, for example, 100.
When the second predetermined value such as km / h is exceeded, the calculation result is distributed and calculated so that the distribution amount to the front wheel side becomes larger than that to the rear wheel side. According to this configuration, the load sharing amount on the front wheel side becomes larger than that on the rear wheel side, so that the steer characteristic of the vehicle becomes the under steer characteristic, and thus the straight running performance in the high speed traveling range of the vehicle can be improved. .

According to yet another detailed feature of the present invention, in any of the above-mentioned configurations, the arithmetic and control unit has a vehicle speed within a range of the first predetermined value or more and the second predetermined value or less. In this case, the calculation result is distributed and calculated so that the distribution amounts to the front wheels and the rear wheels are equal. With this configuration, since the load sharing amount between the front wheels and the rear wheels becomes equal, the steering characteristic of the vehicle can be made the neutral steering characteristic, and thus the steering operation in the normal driving range of the vehicle can be performed. The stability can be improved.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Embodiment FIG. 1 is a block diagram showing one embodiment of an active suspension for a vehicle according to the present invention applied to a four-wheeled vehicle, and FIG. 2 is a schematic view showing one servo actuator shown in FIG. 3 and 4 are block diagrams showing the changeover switch and the automatic front-rear load distributor shown in FIG. 1, respectively.

In FIG. 2, reference numeral 1 denotes a servo actuator, and as shown by 1fr, 1fl, 1rr, 1rl in FIG. 1, the right front wheel, left front wheel, right rear wheel, left Four servo actuators are provided corresponding to the rear wheels. As shown in FIG. 2, each servo actuator 1 is an actuator 4 provided between each wheel 2 and the vehicle body 3 and supporting the vehicle body with respect to the corresponding wheel.
have. The actuator 4 is a cylinder-piston device in the illustrated embodiment, and comprises a cylinder 5 and a piston 6 which is fitted in the cylinder and can be displaced relative to the cylinder substantially only in the vertical direction. , The cylinder 5 and the piston 6 cooperate with each other to define an upper chamber 7 and a lower chamber 8. A rod 9 is fixed to the piston 6, and the rod 9 extends through the end walls at both ends of the cylinder 5, so that even if the piston reciprocates in the cylinder, the volume of the rod in the cylinder is increased. Does not change. Further, the rod 9 supports the wheel 2 at its lower end so as to be rotatable around an axis extending substantially in the vehicle width direction.

The upper chamber 7 and the lower chamber 8 are connected to an electromagnetic hydraulic servo valve 12 by conduits 10 and 11, respectively. The hydraulic servo valve 12 may have a structure known per se,
After continuously receiving high-pressure hydraulic oil generated by a hydraulic pressure generating device 14 such as a pump for sucking the hydraulic oil stored in the reservoir 13 and allowing the hydraulic oil to pass through a variable orifice provided inside, the hydraulic oil Is returned to the reservoir 13, and the pressures in the upper chamber 7 and the lower chamber 8 are adjusted to P by controlling the flow rate of the hydraulic oil with the variable orifice.
₁ and P ₂ (P ₁ > P ₂ ), the differential pressure (P ₁ −P ₂ ) between the pressure in the upper chamber 7 and the pressure in the lower chamber 8 can be arbitrarily controlled. . In the illustrated embodiment, the hydraulic servo valve 12 of each servo actuator is controlled by a control signal (voltage signal) input from the adder 15 via the amplifier 16, and is input from the amplifier 16. When the voltage of the control signal is 0 (as will be described later in detail, each signal input to the adder 15 is Ffb = F ₀ , F
When f = Fr = Fβ = 0), the differential pressure (P ₁ −P
_{2 9} and to generate forces represented by the product A (P 1 _{-P 2)} between the cross-sectional area A of the piston 6 each wheel 2 equal to fair share of shared load of the vehicle body 3 to be supported, the servo actuators 1FR, 1 fl The differential pressure (P ₁ -P ₂ ) of each actuator 4 for ₁ rr and 1 rl is always a constant value Pfr, Pfl, Pr.
When r and Prl are maintained and the voltage of the control signal input from the amplifier 16 has a certain positive and negative value, the differential pressure (P ₁ -P ₂ ) is increased or decreased according to the absolute value of the voltage. It is supposed to do.

A load sensor 17 is provided between the vehicle body 3 and the actuator 4, and the load sensor actually loads a load acting between the vehicle body 3 and each wheel 2, that is, the actuator 4 applies the vehicle body 3 to the wheel 2. The supporting force is detected and a voltage signal Ffb corresponding to the supporting force is output to the minus terminal of the adder 15. The actuator 4 has its rod 9
May be configured to extend only through the lower end wall of the cylinder 5 in the drawing. In that case, since the volume of the rod 9 in the cylinder changes as the piston 6 reciprocates, if the area of the upper surface of the piston is A ₁ and the area of the lower end of the piston is A ₂ , the hydraulic servo valve 12 Amplifier 16
Pressure P ₁ in the upper chamber 7 and the lower chamber 8 according to the control signal from
By changing the internal pressure P ₂ , the generated force A ₁ P ₁
Configured to control -A ₂ P _2. The actuator 4 may be connected to the vehicle body 3 on the rod 9 side and connected to the wheels 2 on the cylinder 5 side. Further reservoir 1
3 and the hydraulic pressure generator 14 may be common to each servo actuator, and the working fluid may be any fluid other than oil as long as it is a substantially incompressible fluid.

In FIG. 1, reference numerals 19 to 21 denote a vehicle width direction acceleration sensor, a roll angular acceleration sensor, and a front-rear direction acceleration sensor, which are provided at or near the center of gravity of the automobile. These sensors detect acceleration in the vehicle width direction, roll angular acceleration, and longitudinal acceleration, respectively, and output signals α, γ, and β indicating the respective accelerations. Particularly in the illustrated embodiment, the sensor 19 outputs positive and negative signals α when the acceleration direction is leftward and rightward as viewed from the rear of the vehicle, and the sensor 20 outputs acceleration signal in the vehicle direction. When it is clockwise and counterclockwise as viewed from the rear, it outputs positive and negative signals γ, respectively, and the sensor 21 outputs negative and negative signals when the acceleration direction is the traveling direction of the vehicle and the opposite direction, respectively. It outputs a positive signal β, and the absolute value of the voltage of the output signals from these sensors corresponds to the magnitude of acceleration.

Vehicle width direction acceleration sensor 19 and roll angular acceleration sensor 2
The signal from 0 is k ₁ by amplifiers 22 and 23, respectively.
After being multiplied by k ₂ times, it is input to the changeover switch 24. As will be described in detail later, the change-over switch 24 is adapted to selectively pass _{one of} the signals αk ₁ and γk ₂ input thereto and output it to the automatic front-rear load distributor 25. As will be described in detail later, the distributor 25 receives a vehicle speed signal V from a vehicle speed sensor 26 and receives an input signal F (αk ₁ from the changeover switch 24 in accordance with the vehicle speed indicated by the vehicle speed signal.
Or γk ₂ ) is distributed to the front wheels and the rear wheels, and the output signal Ff for the front wheels is output to the servo actuator 1fr and the servo actuator 1fl via the sign inverter 27 to output the output signal Fr for the rear wheels to the servo. The signal is output to the actuator 1rr and to the servo actuator 1rl via the sign inverter 28.

While the output signal from the longitudinal acceleration sensor 21 is inputted to the servo actuators 1fr and 1fl after the voltage thereof is ₃ times k by an amplifier 29, also respectively servo actuator 1rr through the sign inverter 30, and 31 and 1rl
It is designed to be input to.

Amplifiers 22 and 23, changeover switch 24, distributor 2
5, the sign inverters 27 and 28, the amplifier 29, the sign inverters 30 and 31, the adder 15 and the amplifier 16 of each servo actuator are caused by the acceleration of the vehicle body rather than the output signals from the respective sensors, as will be described in detail later. The calculation control device is configured to calculate the variation amount of the load acting between each wheel and the vehicle body and output the control signal to the hydraulic servo valve 12 based on the calculation result. The amplification factors k ₁ , k ₂ , k ₃ of the amplifiers 22, 23, 29 are constants that may be calculated or experimentally obtained, for example.

The changeover switch 24, as shown in detail in FIG.
It has input terminals 33 and 34 for receiving signals from the amplifiers 22 and 23, respectively, and an output terminal 35 for outputting signals to the distributor 25. The signal from the amplifier 22 input at the input terminal 33 is input to the gate 36 and the comparator 37. The signal input to the comparator 37 is compared with the reference potential, which is 0 potential in the illustrated embodiment, and then output to the AND circuit 38 and the NOR circuit 39. Similarly, the signal from the amplifier 23 input at the input terminal 34 is the gate 4
0 and the comparator 41. The signal input to the comparator 41 is compared with a reference potential, which is 0 potential in the illustrated embodiment, and then output to the AND circuit 38 and the NOR circuit 39. The output signals from the AND circuit 38 and the NOR circuit 39 are input to the OR circuit 42, the output signal from the OR circuit 42 is output to the gate 36, and also to the gate 40 via the NOT circuit 43, whereby the gates 36 and 40 are It is designed to be opened and closed as an alternative.

The changeover switch 24 operates as follows to selectively output one of the input signals received at the input terminals 33 and 34 to the distributor 25 via the output terminal 35. That is, the signal input through the input terminal 33 is 0 in the comparator 37.
It is compared with the potential, and if the signal is positive, it becomes a high level signal, and if it is negative, it becomes a low level signal. Similarly, input terminal 3
The signal input at 4 is compared with the 0 potential in the comparator 41. If the signal is positive, it becomes a high level signal, and if it is negative, it becomes a low level signal. The signals from the comparators 37 and 41 are input to the AND circuit 38, and a high level signal is output from the AND circuit only when both signals are high level. The signals from the comparators 37 and 41 are NO.
The NOR circuit 39 outputs a high level signal only when both signals are input to the R circuit 39 and are low level.

That is, only when the signs of the signals input to the changeover switch 24 at the input terminals 33 and 34 are the same, the AND circuit 3
8 or NOR circuit 39 outputs a high level signal to the OR circuit 42. Therefore, the OR circuit 42 has the input terminal 3
If the signs of the signals from 3 and 34 are the same, a high level signal is output, thereby opening the gate 36 and closing the gate 40, whereby only the signal input at the input terminal 33 is output from the output terminal 35. Output. Conversely, the input terminal 33
When the signs of the signals input to the input terminals 34 and 34 do not match, the output of the OR circuit 42 becomes a low level signal, and thus the signal is input via the NOT circuit 43 to the gate 40.
Is opened and the gate 36 is closed, whereby the signal input at the input terminal 34 is output from the output terminal 35.

Thus, when the signals from the amplifiers 22 and 23 have the same sign, the changeover switch 24 outputs the signal F (αk ₁ ) from the amplifier 22 to the distributor 25 and the amplifier 22.
If the signs of the signals from 23 and 23 do not match,
The signal F (γk ₂ ) from the amplifier 23 is output to the distributor 25.

As shown in detail in FIG. 4, the automatic front-rear load distributor 25 has an input terminal 44 for receiving a signal F from the changeover switch 24, an input terminal 45 for receiving a vehicle speed signal V from a vehicle speed sensor 26, and a front wheel. It has an output terminal 46 for outputting a signal Ff to the actuators 1fr and 1fl, and an output terminal 47 for outputting a signal Fr to the rear wheel actuators 1rr, 1rl. Changeover switch 24 input at input terminal 44
The signal F from the signal is input to the adder 50 via the gate 49 after the voltage e is reduced to 1 / 2e by the multiplier 48 having a coefficient of 1/2, or the adder 5 via the gate 51 and the multiplier 52.
It is adapted to be input to 0 or to the adder 50 via the gate 53 and the multiplier 54.

The gates 49, 51 and 53 are comparators 55 to 55, respectively.
The opening / closing control is performed by 57. The comparator 55 compares the voltage Ev of the vehicle speed signal V input at the input terminal 45 with the reference potential Ev _1, and turns on when Ev ≧ Ev ₁ to open the gate 49, and turns off when Ev <Ev _1. This is a high frequency comparator that closes the gate 49 by means of a gate. The comparator 56 compares the voltage Ev of the vehicle speed signal V with the reference potential Ev _1, and turns on when Ev <Ev ₁ to open the gate 51, and turns off when Ev ≧ Ev ₁ to close the gate 51. Is. Comparator 5
Reference numeral 7 designates the voltage Ev of the vehicle speed signal V as a reference potential Ev ₂ (Ev ₂ >
Compared with Ev ₁ ), when Ev> Ev ₂ is turned on and the gate 53 is opened, and when Ev ≦ Ev ₂ is turned off, the gate 5 is turned on.
3 is a high frequency comparator for closing 3.

The other input of the multiplier 52 is a signal of the voltage of Ev / Ev ₁ input at the input terminal 45 and multiplied by 1 / Ev ₁ by the amplifier 58. Therefore, the signal input from the multiplier 52 to the adder 50 is Is a voltage signal. Further, the other input of the multiplier 54 is subjected to Ev-Ev ₂ calculation processing by the adder 59 and multiplied by 1 / (Evm-Ev ₂ ) by the multiplier 60 (E _v −
A signal having a voltage of E _v2 ) / (E _vm −E _v2 ), and therefore the signal input from the multiplier 54 to the adder 50 is Is a voltage signal. In this case, Evm is a value corresponding to the voltage of the vehicle speed signal from the vehicle speed sensor 26 when the vehicle is at its maximum traveling speed, and Evm> Ev ₂ .
The output of the adder 50 is output from the amplifier 61 via the output terminal 46 to the front wheel actuator as the output terminal Ff,
Also, after the voltage Fr = F-Ff is processed by the amplifier 62, the voltage is output from the output terminal 47 to the rear wheel actuator. The amplifier 61 may be omitted.

Thus, the gates 49, 51 and 53 have the voltage E of the vehicle speed signal V.
Open alternatively according to v. When 0 ≦ Ev <Ev ₁ , only the gate 51 is opened, so that the voltages of the output signals Ff and Fr from the terminals 46 and 47 are respectively Becomes In this case, since Ev <Ev ₁ , Ev / Ev ₁
Since <1 and therefore the voltage of the signal Ff is smaller than the voltage of the signal Fr, the steer characteristic of the vehicle becomes the over steer characteristic. In this case, as shown in FIG. 5, the voltage of the signal Ff is In the range of less than, it increases linearly as the vehicle speed increases, and therefore the degree of oversteer characteristic decreases and approaches the neutral steer characteristic as the vehicle speed increases.

Further, when Ev ₁ ≦ Ev ≦ Ev ₂ , only the gate 49 is opened, so that the output signals Ff from the terminals 46 and 47,
Fr voltage is the same for both Since the distribution amount of the load is equal between the front and rear wheels, the steer characteristic of the vehicle becomes the neutral steer characteristic. In this case, as shown in FIG. 5, the signals Ff, F
The voltage of r is regardless of the vehicle speed Is maintained at a constant value.

Further, when Ev ₂ <Ev, only the gates 49 and 53 are opened, and the voltages of the output signals Ff and Fr from the terminals 46 and 47 are respectively Since (Ev−Ev ₂ ) / (Evm−Ev ₂ ) is greater than 0 and less than or equal to 1, the voltage of the signal Ff is greater than the voltage of Fr and the load distribution amount on the front wheel side rather than the rear wheel side. Is increased, and as a result, the steer characteristic of the vehicle becomes the under steer characteristic. In this case, as shown in FIG.
The voltage of the signal Ff is Is larger than e and linearly increases as the vehicle speed increases, and as the vehicle speed increases, the degree of the understeer characteristic becomes larger than the characteristic close to the neutral steer characteristic.

As shown in FIG. 2, each servo actuator 1
The adder 15 has three positive input terminals and one negative input terminal. Output signals Ff or Fr from the automatic front / rear load distributor 25, an output signal Fβ from the amplifier 29, and corresponding wheels 2 when the vehicle is in a stopped state or a constant-speed straight traveling state are provided to the positive input terminals, respectively. Is inputted with a voltage signal F ₀ corresponding to a proportional share load of the vehicle body 3 to be carried, and an output signal from the load sensor 17, that is, an actual signal acting between the vehicle body 3 and each wheel 2 is input to the negative terminal. The signal Ffb indicating the load is input. Therefore, the differential pressure (P ₁ -P ₂ ) between the pressure P ₁ in the upper chamber 7 and the pressure P ₂ in the lower chamber 8 of the actuator 4 is set by the hydraulic servo valve 12 based on the signal Ff or the signal Fr and the signal Fβ. The feedback control is performed by the signal of Ffb−Ff (or Fr) −Fβ−F ₀ so that Ffb = Ff (or Fr) + Fβ + F ₀ is satisfied while the amount is increased or decreased.

In FIG. 1, the input path of the signal F ₀ to each servo actuator is not shown for the sake of simplification, but the signal F ₀ indicates that the vehicle is in a stopped state or in a low-speed straight traveling state. In the above, as a signal of a voltage corresponding to the corresponding shared load of the vehicle body to be carried by each corresponding wheel, the correspondence of the adder 15 of each servo actuator 1 from an arbitrary constant voltage signal generator not shown in the figure It may be input to one negative input terminal. When the active suspension of the present invention is controlled in an open loop system, the input paths for the signal Ffb and the signal F ₀ from the load sensor 17 may be omitted.

Next, the operation of the embodiment configured as described above will be described.

First, when the vehicle is in a stopped state or in a constant-speed straight traveling state, the acceleration of the vehicle body 3 is 0 in any direction, so the outputs of the sensors 19 to 21 are 0, and Ffb = F ₀
Therefore, the output of the adder 28 is also 0, so that the differential pressure (P ₁ -P ₂ ) of each actuator 4 of the servo actuators 1fr, 1fl, 1rr, and 1rl is a constant value P.
The attitude of the vehicle body 3 is maintained in a predetermined state by maintaining fr, Pfl, Prr, and Prl. Further, when the wheel 2 passes through the unevenness of the road surface while the vehicle is traveling straight at a constant speed, the force that the wheel receives from the road surface temporarily changes, but in this case as well, the differential pressure (P ₁ − P ₂ ) is kept constant, and therefore the force generated by the actuator between the wheel and the vehicle body, that is, the supporting force on the vehicle body is also kept constant, so that the piston 6 of each actuator moves in accordance with the vertical displacement of the wheel.
Although the vehicle body is vertically displaced relative to the vehicle body, the vehicle body is not vertically displaced and remains at a predetermined height position, whereby the posture of the vehicle body is maintained in a predetermined state.

Next, the turning of the vehicle will be described. When the vehicle turns, a centrifugal force acts on the vehicle body 3 toward the outside of the turning, and the center of gravity of the vehicle body is located higher than the ground contact point of the wheels. Therefore, the vehicle body 3 rolls to the outside of the turning, and centripetal acceleration and roll are performed. It makes a motion with angular acceleration, and these accelerations are detected by the sensor 19 respectively.
And 20. In this case, the variation amount of the load acting between each wheel and the vehicle body is substantially proportional to the acceleration of the vehicle body regardless of the turning direction of the vehicle. Further, the directions of the vehicle width direction acceleration (centripetal acceleration) and the roll angular acceleration are opposite to each other in the direction of relative movement with respect to the center of gravity of an arbitrary portion above the center of gravity of the vehicle, and therefore are input to the changeover switch 24. The sign of the output signals from the amplifiers 22 and 23 is the same, so in this case only the signal based on the signal output by the sensor 19 is present in each servo actuator 1.
Is input to.

Assuming that the vehicle is now turning to the left, the direction of the vehicle width direction acceleration (centripetal acceleration) of the vehicle body 3 is to the left when viewed from the rear of the vehicle, and the direction of the roll angular acceleration is clockwise when viewed from the rear of the vehicle. , I.e., to the right in the direction of relative movement with respect to the center of gravity of any portion above the center of gravity of the vehicle body, and thus the signals α and γ output from the sensors 19 and 20 are both positive, they are amplified by the amplifier 22. Only α k ₁ passes through the changeover switch 24 and is input to the distributor 25. The signal input to the distributor 25 is divided into the input signal Ff for the front wheels and the input signal Fr for the rear wheels at a predetermined ratio according to the voltage Ev of the vehicle speed signal from the vehicle speed sensor 26 as described above. The output signal Ff from the distributor 25 is input to the adder 15 of the servo actuator 1fr for the right front wheel, and the hydraulic servo valve 12 responds to the increase in the load acting between the right front wheel and the vehicle body 3 on the right front wheel. The differential pressure (P ₁ -P ₂ ) of the actuator 4 for the vehicle is increased above Pfr, and the distributor 2
The output signal Ff from the signal No. 5 is sign-inverted by the sign inverter 27 and inputted as a negative signal to the adder 15 of the servo actuator 1fl for the left front wheel, and the hydraulic servo valve 12 acts between the left front wheel and the vehicle body 3. The differential pressure (P ₁ -P ₂ ) of the actuator 4 for the left front wheel is reduced below Pfl in accordance with the amount of decrease in the load, which prevents the front wheel roll of the vehicle body 3.

Similarly, the output signal Fr from the distributor 25 is input to the adder 15 of the servo actuator 1rr for the right rear wheel, and corresponds to the increase amount of the load acting between the right rear wheel and the vehicle body 3 by the hydraulic servo valve 12. Then, the differential pressure (P ₁ -P ₂ ) of the actuator 4 for the right rear wheel is increased from Prr, and the output signal Fr from the distributor 25 is sign-inverted by the sign inverter 28 to give a negative signal to the left rear. Servo actuator for wheels 1rl
The differential pressure (P ₁ -P ₂ ) of the actuator 4 for the left rear wheel, which is input to the adder 15 of the hydraulic servo valve 12 and corresponds to the reduction amount of the load acting between the left rear wheel and the vehicle body 3 by the hydraulic servo valve 12. Is Prl
It is further reduced, whereby rolling on the rear wheel side of the vehicle body 3 is prevented. Thus, when the vehicle turns left, the body 3 is prevented from rolling in the clockwise direction as viewed from the rear of the vehicle.

Similarly, when the vehicle turns right, the output signals α and γ from the sensors 19 and 20 are both negative, so only the negative αk ₁ signal passes through the changeover switch 24, and the negative signals Ff from the distributor 25 are obtained. , Fr are input to the servo actuator 1fr for the right front wheel and the servo actuator 1rr for the right rear wheel, whereby the right front wheel, the right rear wheel and the vehicle body 3 are respectively received.
The differential pressures (P ₁ -P ₂ ) of the actuators 4 for the right front wheel and the right rear wheel are reduced from Pfr and Prr, respectively, in accordance with the amount of decrease in the load acting between them and the signal from the distributor 25. Is inverted by the sign inverters 27 and 28 and input as positive signals Ff and Fr to the left front wheel servo actuator 1fl and the left rear wheel servo actuator 1rl, respectively, so that the left front wheel and the left rear wheel and the vehicle body 3 The differential pressures (P ₁ -P ₂ ) of the left front wheel actuator 4 and the left rear wheel actuator 4 are increased from Pfl and Prl, respectively, corresponding to the increased load acting between the vehicle body 3 and the vehicle body 3. Rolling counterclockwise when viewed from behind is prevented.

Next, a case where the vehicle receives a relatively strong side wind such as a gust will be described. When the vehicle receives a crosswind, the pushing force of the crosswind acting on the vehicle body drives the vehicle body to the leeward side, and the upper part of the vehicle body is rolled in the direction of moving to the leeward side. At times, it behaves like centrifugal force. In this case, the variation amount of the load acting between each wheel and the vehicle body is substantially proportional to the pressing force by the side wind acting on the vehicle body, and thus the roll angular acceleration of the vehicle body.

However, the direction of the acceleration in the vehicle width direction detected by the vehicle width direction acceleration sensor 19 is opposite to the rolling direction of the vehicle in the case of turning of the vehicle, whereas it is opposite to the rolling direction of the vehicle in the case of turning of the vehicle. Of the lateral acceleration sensor 19 and the output γ of the roll angular acceleration sensor 20 are compared, and if the signs are different, the roll of the vehicle body is It can be seen that it is not due to the turning, but because the vehicle body receives a side wind. When the vehicle receives a cross wind, the amount of movement of the vehicle body 3 in the leeward direction is small, while the amount of movement of the vehicle body 3 is small.
The roll amount is relatively large and increases substantially in proportion to the cross wind strength. Therefore, in this case, it is preferable that the differential pressure (P ₁ -P ₂ ) of the actuator 4 of each wheel is controlled based on the roll angular acceleration rather than based on the vehicle width direction acceleration.

Assuming that the vehicle is now subjected to a crosswind from the left, the vehicle body 3 moves to the right as viewed from the rear of the vehicle and rolls in the clockwise direction. Therefore, the vehicle body 3 moves to the right with the vehicle width direction acceleration and the clockwise direction, that is, with the roll angular acceleration to the right as viewed in the direction of relative movement with respect to the center of gravity of an arbitrary portion above the center of gravity of the vehicle body. Therefore, the output α of the vehicle width direction acceleration sensor 19 is negative, while the output γ of the roll angular acceleration sensor 20 is positive, and therefore the positive signal γk output by the sensor 20 and amplified by the amplifier 23.
₂ passes through the changeover switch 24 and is divided by the distributor 25 into the front and rear wheels at a predetermined ratio according to the vehicle speed.
It is input to each servo actuator as f and Fr.
In this case, the positive signals Ff and Fr from the distributor 25 are input to the servo actuators 1fr and 1rr, respectively, and the negative signals F whose signs are inverted by the sign inverters 27 and 28 are supplied.
f and Fr are servo actuators 1fl and 1rl, respectively
Is input to the vehicle body 3 as in the case of turning the vehicle described above.
The differential pressure of the actuators 4 for the right front wheel and the right rear wheel (corresponding to the increase amount of the load acting between the right front wheel and the right rear wheel and the vehicle body due to the pressing force of the side wind acting on P ₁ −
P ₂ ) is increased from Pfr and Prr, respectively, and the differential pressures of the actuators 4 for the left front wheel and the left rear wheel are respectively corresponding to the reduction amount of the load acting between the left front wheel and the left rear wheel and the vehicle body. P ₁ −P ₂ ) is reduced from Pfl and Prl, respectively, thereby preventing the vehicle body from rolling in the leeward direction.

Similarly, when the vehicle receives a cross wind from the right side, the output signal α from the vehicle width direction acceleration sensor 19 is positive and the output signal γ from the roll angular acceleration sensor 20 is negative. Also, only the negative signal γk ₂ output from the sensor 20 and amplified by the amplifier 23 is applied to the changeover switch 24.
And divided into the front and rear wheels as signals Ff and Fr by a distributor 25 at a predetermined ratio according to the vehicle speed, and the negative signals Ff and Fr are supplied to the right front wheel servo actuator 1fr and the right rear wheel servo actuator 1rr. The positive signals Ff and Fr, which have been input and whose signs have been inverted by the sign inverters 27 and 28, are input to the left front wheel servo actuator 1fl and the left rear wheel servo actuator 1rl, respectively. Similarly, the differential pressure (P ₁ of the actuators 4 for the left front wheel and the right rear wheel, respectively) corresponding to the increasing amount of the load acting between the left front wheel and the left rear wheel and the vehicle body due to the cross wind.
-P ₂₎ respectively Pfl, it is increased from Prl, corresponding to the amount of decrease in load acting between the right front wheel and the right rear wheel and the vehicle body, the differential pressure of the actuator 4 of each for the right front wheel and the right rear wheel (P ₁ -P ₂ ) is reduced from Pfr and Prr, respectively, thereby preventing the downward roll of the vehicle body.

Next, the acceleration / deceleration of the vehicle will be described. When the vehicle accelerates, the body moves with acceleration in the direction of travel of the vehicle,
Since the inertial force in the direction opposite to the traveling direction acts on the vehicle body,
The load acting between the left and right front wheels and the vehicle body decreases, and the load acting between the left and right rear wheels and the vehicle body increases, causing squat of the vehicle body. Conversely, when the vehicle decelerates, the vehicle body moves with acceleration in the direction opposite to the traveling direction of the vehicle, and inertial force acts on the vehicle body in the traveling direction of the vehicle, so that it acts between the left and right front wheels and the vehicle body. The load acting on the vehicle increases and the load acting between the left and right rear wheels and the vehicle body decreases, resulting in a nose dive of the vehicle body. In this case, the variation amount of the load acting between the wheel and the vehicle body is substantially proportional to the longitudinal acceleration of the vehicle body in both acceleration and deceleration of the vehicle.

Assuming that the vehicle is now in an accelerating state, the acceleration in the traveling direction of the vehicle is detected by the sensor 21, the negative output β of the sensor is amplified by the amplifier 29, and the negative signal F
Servo actuator for right front wheel 1fr as β (βk ₃ )
And a positive signal −Fβ (−βk ₃ ) which is input to the left front wheel servo actuator 1fl and whose sign has been inverted by the sign inverters 30 and 31 to the right rear wheel servo actuator 1rr and the left rear wheel servo actuator 1rl. The differential pressure (P ₁ -P ₂ ) of the left and right front wheel actuators 4 is Pfl, which corresponds to the amount of reduction of the load that is input and acts between the left and right front wheels and the vehicle body due to the inertial force that acts on the vehicle body.
Pfr is decreased, and the differential pressure (P ₁ -P ₂ ) of the actuator 4 for the left and right rear wheels is increased from Prl and Prr, respectively, corresponding to the increase amount of the load acting between the left and right rear wheels and the vehicle body. This prevents the squat of the car body.

Further, when the vehicle is in the deceleration state, the acceleration of the vehicle body in the direction opposite to the traveling direction of the vehicle is detected by the sensor 21,
The positive output β of the sensor is amplified by the amplifier 29 and input as a positive signal Fβ (βk ₃ ) to the right front wheel servo actuator 1fr and the left front wheel servo actuator 1fl, and the sign invertors 30 and 31 invert the sign. has been negative signal -Fβ (-βk ₃₎ servo actuators for the right rear wheel 1rr and the servo actuator 1 _rl for the left rear wheel
Is input to the left and right front wheels and the vehicle body due to the inertial force acting on the vehicle body, and the differential pressure (P ₁ −P ₂ ) of the left and right front wheel actuators 4 is Pfl respectively. , Pfr is increased, and the differential pressure (P ₁ -P ₂ ) of the actuator 4 for the left and right rear wheels is decreased from Prl and Prr, respectively, in accordance with the amount of decrease in the load acting between the left and right rear wheels and the vehicle body. This prevents the nose dive of the vehicle body.

When the vehicle turns with acceleration / deceleration or when a vehicle receives a crosswind while traveling straight ahead with acceleration / deceleration, the differential pressure (P ₁ -P ₂ ) of each actuator 4 is different. It is controlled by a combination of the above-described acceleration / deceleration operation and turning operation, and a combination of the acceleration / deceleration operation and the operation when the vehicle receives a side wind.

From the above description, according to the illustrated embodiment, not only when the vehicle turns, but also when the vehicle receives a crosswind or when the vehicle is accelerated or decelerated, the vehicle body shakes relatively greatly or the vehicle body is desired. It is prevented from changing more greatly than the posture, which improves the riding comfort and steering stability of the vehicle, and the steer characteristics of the vehicle are appropriately changed according to the running speed of the vehicle. It will be understood that the steering performance is improved, the steering stability is improved in the normal driving range, and the straight running performance is improved in the high speed driving range.

FIG. 6 is a block diagram similar to FIG. 1, showing another embodiment of the vehicle active suspension according to the present invention applied to a four-wheeled vehicle, and FIG. 7 is a switching diagram shown in FIG. It is a block diagram similar to FIG. 3 which shows a switch. In these figures, the members substantially the same as the members shown in FIGS. 1 and 3 are designated by the same reference numerals.

In this embodiment, the changeover switch 24 has two output terminals 35a and 35b, each of which has a gate 3
The signal passed through 6 and 40 is output. The output terminal 35a is connected to the input terminal (44) of the automatic front-rear load distributor 25, and the output terminal 35b is connected to the distributor 25a. The changeover switch 24 is configured similarly to the changeover switch shown in FIG. 3 in other points. Thus, the changeover switch 24 is connected to the amplifier 2
When the signs of the signals from 2 and 23 are the same, the signal F (αk ₁ ) from the amplifier 22 is output to the automatic front-rear load distributor 25, and the signs of the signals from the amplifiers 22 and 23 are equal. If not, the signal F (γk ₂ ) from the amplifier 23 is output to the distributor 25a.

The distributor 25a changes the voltage of the signal input thereto to Nf: N.
constant ratio of r (Nf> 0, Nr> 0, Nf + Nr =
1) and distribute the signal γk ₂ Nf to actuator 1fr
To the actuator 1fl via the sign inverter 27, and the signal γk ₂ Nr to the actuator 1rr and to the actuator 1rl via the sign inverter 28.

Thus, according to this embodiment, the changeover switch 24 determines whether the vehicle is turning or the vehicle receives a crosswind, and when the vehicle is turning, the changeover switch 24
The signal αk ₁ is output to the automatic front-rear load distributor 25,
Similar to the case of the above-mentioned embodiment, the roll of the vehicle body is effectively prevented, and the steer characteristic of the vehicle is appropriately controlled according to its traveling speed. Further, when the vehicle receives a cross wind, the changeover switch 24 outputs the signal γk ₂ to the distributor 25a, which in turn outputs the signals distributed to the actuators at a predetermined ratio. As in the case of the embodiment, the roll of the vehicle body is effectively prevented when the vehicle receives a cross wind.

In this case, by appropriately setting the signal distribution ratio by the distributor 25a, it is possible to arbitrarily set the steer characteristic when the vehicle receives a side wind. That is, Nf = N
If r = 0.5 is set, the variation amount of the load acting between the wheel and the vehicle body due to the wind pressure acting on the vehicle body is evenly distributed between the front wheels and the rear wheels. The steer characteristic of can be a neutral steer characteristic. Further, if Nf> Nr is set, the amount of variation in the load acting between the wheel and the vehicle body due to the wind pressure acting on the vehicle body is larger on the front wheel side than on the rear wheel side, so the steer characteristic of the vehicle is improved. It can have an understeer characteristic. On the other hand, if Nf> Nr is set, the amount of variation in the load acting between the wheel and the vehicle body due to the wind pressure acting on the vehicle body is larger on the rear wheel side than on the front wheel side, so the steer characteristic of the vehicle is increased. Can be an oversteer characteristic.

Although the present invention has been described in detail above with respect to specific embodiments, the present invention is not limited to such embodiments, and various embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a vehicle active suspension according to the present invention applied to a four-wheeled vehicle, and FIG. 2 is a schematic configuration diagram showing a servo actuator provided corresponding to each wheel, FIGS. 3 and 4 are block diagrams showing the changeover switch and the automatic front-rear load distributor shown in FIG. 1, respectively, and FIG. 5 is input from the automatic front-rear load distributor to the front and rear wheel servo actuators. FIG. 6 is a graph showing the relationship between the voltages of the signals Ff and Fr to be applied and the voltage Ev of the vehicle speed signal. FIG. 6 is a first embodiment showing another embodiment of the vehicle active suspension according to the present invention applied to a four-wheeled vehicle. 7 is a block diagram similar to FIG. 7, and FIG. 7 is a block diagram similar to FIG. 3 showing the changeover switch shown in FIG. 1 ... Servo actuator, 2 ... Wheel, 3 ... Car body, 4 ... Actuator, 5 ... Cylinder, 6 ... Piston, 7 ... Upper chamber, 8 ... Lower chamber, 9 ... Rod, 1
0, 11 ... Conduit, 12 ... hydraulic servo valve, 13 ... reservoir, 14 ... hydraulic pressure generator, 15 ... adder, 16
…… Amplifier, 19 …… Vehicle width direction acceleration sensor, 20 ……
Roll angular acceleration sensor, 21 ... longitudinal acceleration sensor, 22, 23 ... amplifier, 24 ... changeover switch, 2
5 ... Automatic front-rear load distributor, 25a ... Distributor, 26 ...
... vehicle speed sensor, 27, 28 ... sign inverter, 29 ... amplifier, 30, 31 ... sign inverter, 33, 34 ... input terminal, 35, 35a, 35b ... output terminal, 36 ... gate, 37 ... Comparator, 38 ... AND circuit, 39 ...
NOR circuit, 40 ... Gate, 41 ... Comparator, 42 ...
... OR circuit, 43 ... NOT circuit, 44, 45 ... Input terminal, 46, 47 ... Output terminal, 48 ... Multiplier, 49
... gate, 50 ... adder, 51 ... gate, 52 ...
... multiplier, 53 ... gate, 54 ... multiplier, 55-5
7 ... Comparator, 58 ... Amplifier, 59 ... Adder, 60 ... Multiplier, 61, 62 ... Amplifier

Claims (16)

[Claims] 1. A plurality of actuators provided between each wheel of a vehicle and a vehicle body for supporting the vehicle body with respect to the corresponding wheels, and a vehicle width direction acceleration detection for detecting an acceleration of the vehicle body in the vehicle width direction. Means, vehicle speed detection means for detecting the traveling speed of the vehicle, vehicle width direction acceleration signals and vehicle speed signals from the acceleration detection means and the vehicle speed detection means, respectively, and the vehicle speed direction of the vehicle body in the vehicle width direction from the acceleration signals. The total variation amount of the load acting between each one-sided front and rear wheels and the vehicle body due to acceleration is calculated, and the calculation result is distributed to the front and rear wheels at a ratio according to the vehicle speed indicated by the vehicle speed signal, An active suspension for a vehicle including an arithmetic control unit that controls each actuator based on the calculation result and increases or decreases the force acting between the corresponding wheel and the vehicle body via the actuator ® down. 2. The active suspension for a vehicle according to claim 1, wherein the arithmetic and control unit has a larger distribution amount to the rear wheel side than to the front wheel side when the vehicle speed is less than a first predetermined value. An active suspension for a vehicle, which is configured to perform a distribution calculation of the calculation result. 3. The vehicle active suspension according to claim 1 or 2, wherein the arithmetic and control unit distributes to the front wheel side rather than the rear wheel side when the vehicle speed exceeds a second predetermined value. An active suspension for a vehicle, which is configured to perform a distribution calculation of the calculation result so as to increase the amount. 4. The vehicle active suspension according to claim 3, wherein the arithmetic and control unit controls the front and rear wheels when the vehicle speed is equal to or higher than the first predetermined value and equal to or lower than the second predetermined value. An active suspension for a vehicle, which is configured to perform a distribution calculation of the calculation result so that the distribution amount to the side becomes equal. 5. A plurality of actuators provided between each wheel of the vehicle and the vehicle body to support the vehicle body with respect to the corresponding wheels, and a vehicle width direction acceleration detection for detecting acceleration of the vehicle body in the vehicle width direction. Means, vehicle speed detection means for detecting the traveling speed of the vehicle, vehicle width direction acceleration signals and vehicle speed signals from the acceleration detection means and the vehicle speed detection means, respectively, and the vehicle speed direction of the vehicle body in the vehicle width direction from the acceleration signals. The total variation amount of the load acting between each one-sided front and rear wheels and the vehicle body due to acceleration is calculated, and the calculation result is distributed to the front and rear wheels at a ratio according to the vehicle speed indicated by the vehicle speed signal, A control unit that controls each actuator based on the calculation result and increases or decreases the force acting between the corresponding wheel and the vehicle body via the actuator, and each actuator is supported by Fluctuation amount of the force supported by each actuator detected by a plurality of load detecting means for detecting the force and the fluctuation of the load acting between the wheels and the vehicle body calculated by the arithmetic and control unit. An active suspension for a vehicle, which is configured to be feedback-controlled so as to compare the amount and the deviation between the two to zero. 6. The vehicle active suspension according to claim 5, wherein the arithmetic and control unit has a larger distribution amount to the rear wheel side than to the front wheel side when the vehicle speed is less than a first predetermined value. An active suspension for a vehicle, which is configured to perform a distribution calculation of the calculation result. 7. The active suspension for vehicle according to claim 5 or 6, wherein the arithmetic and control unit distributes to the front wheel side rather than the rear wheel side when the vehicle speed exceeds a second predetermined value. An active suspension for a vehicle, which is configured to perform a distribution calculation of the calculation result so as to increase the amount. 8. The vehicle active suspension according to claim 7, wherein the arithmetic and control unit controls the front wheels and the rear wheels when the vehicle speed is equal to or higher than the first predetermined value and equal to or lower than the second predetermined value. An active suspension for a vehicle, which is configured to perform a distribution calculation of the calculation result so that the distribution amount to the side becomes equal. 9. A plurality of actuators provided between each wheel of the vehicle and the vehicle body to support the vehicle body with respect to the corresponding wheels, and a vehicle width direction acceleration detection for detecting an acceleration of the vehicle body in the vehicle width direction. Means, roll angular acceleration detecting means for detecting angular acceleration in the roll direction of the vehicle body, vehicle speed detecting means for detecting traveling speed of the vehicle, vehicle width direction acceleration detecting means, roll angular acceleration detecting means, and A vehicle width direction acceleration signal, a roll angular acceleration signal, and a vehicle speed signal are respectively input from the vehicle speed detection means, and whether the vehicle is turning or whether the vehicle receives a crosswind from the vehicle width direction acceleration signal and the roll angular acceleration signal. If it is determined that the vehicle is turning, one-sided front and rear vehicles due to acceleration in the vehicle width direction of the vehicle body from the vehicle width direction acceleration signal are determined. And the vehicle body, the total amount of fluctuation of the load acting between the vehicle body and the vehicle body is calculated, and when it is determined that the vehicle receives a side wind, the roll angular acceleration signal causes acceleration of the vehicle body in the roll direction. The total fluctuation amount of the load acting between each one-side front and rear wheel and the vehicle body is calculated, and the calculation result is distributed to the front and rear wheels at a ratio according to the vehicle speed indicated by the vehicle speed signal. An active suspension for a vehicle, comprising: an arithmetic and control unit that controls each actuator based on the above, and increases or decreases the force acting between the corresponding wheel and the vehicle body via the actuator. 10. The vehicle active suspension according to claim 9, wherein the arithmetic and control unit distributes more to the rear wheels than to the front wheels when the vehicle speed is less than a first predetermined value. An active suspension for a vehicle, which is configured to perform a distribution calculation of the calculation result. 11. The vehicle active suspension according to claim 9 or 10, wherein the arithmetic and control unit distributes to the front wheel side rather than the rear wheel side when the vehicle speed exceeds a second predetermined value. An active suspension for a vehicle, which is configured to perform a distribution calculation of the calculation result so as to increase the amount. 12. The vehicle active suspension according to claim 11, wherein the arithmetic and control unit controls the front wheels and the rear wheels when the vehicle speed is equal to or higher than the first predetermined value and equal to or lower than the second predetermined value. An active suspension for a vehicle, which is configured to perform a distribution calculation of the calculation result so that the distribution amount to the side becomes equal. 13. A plurality of actuators provided between each wheel of a vehicle and a vehicle body for supporting the vehicle body with respect to the corresponding wheels, and a vehicle width direction acceleration detection for detecting an acceleration of the vehicle body in the vehicle width direction. Means, roll angular acceleration detecting means for detecting angular acceleration in the roll direction of the vehicle body, vehicle speed detecting means for detecting traveling speed of the vehicle, vehicle width direction acceleration detecting means, roll angular acceleration detecting means, and A vehicle width direction acceleration signal, a roll angular acceleration signal, and a vehicle speed signal are respectively input from the vehicle speed detection means, and whether the vehicle is turning or whether the vehicle receives a crosswind from the vehicle width direction acceleration signal and the roll angular acceleration signal. If it is determined that the vehicle is turning, the front and rear sides of each side due to the acceleration of the vehicle body in the vehicle width direction from the vehicle width direction acceleration signal are determined. When the total variation amount of the load acting between the wheel and the vehicle body is calculated and it is determined that the vehicle receives a crosswind, the roll angular acceleration signal is used to accelerate the vehicle body in the roll direction. The total variation amount of the load acting between each one side front and rear wheel and the vehicle body is calculated, and the calculation result is distributed to the front and rear wheels at a ratio according to the vehicle speed indicated by the vehicle speed signal, and the calculation is performed. A plurality of load detections for detecting the force supported by each actuator, including an arithmetic and control unit that controls each actuator based on the result and increases or decreases the force acting between the corresponding wheel and the vehicle body via the actuator The actual fluctuation amount of the force supported by each actuator detected by the means is compared with the fluctuation amount of the load acting between the wheels and the vehicle body calculated by the arithmetic and control unit, and the deviation between the two is zero. Sir Configured active suspension for a vehicle as intoxicated is feedback-controlled. 14. The active suspension for a vehicle according to claim 13, wherein the arithmetic and control unit distributes more to the rear wheels than to the front wheels when the vehicle speed is less than a first predetermined value. An active suspension for a vehicle, which is configured to perform a distribution calculation of the calculation result. 15. The active suspension for a vehicle according to claim 13 or 14, wherein the arithmetic and control unit distributes to the front wheel side rather than the rear wheel side when the vehicle speed exceeds a second predetermined value. An active suspension for a vehicle, which is configured to perform a distribution calculation of the calculation result so as to increase the amount. 16. The vehicle active suspension according to claim 15, wherein the arithmetic and control unit controls the front wheels and the rear wheels when the vehicle speed is equal to or higher than the first predetermined value and equal to or lower than the second predetermined value. An active suspension for a vehicle, which is configured to perform a distribution calculation of the calculation result so that the distribution amount to the side becomes equal.