JPH01111513A - Variable damping force-type suspension controller - Google Patents

Abstract

PURPOSE:To improve a suspension characteristic by estimating a forthcoming variation in the state quantity of a vehicle according to a variation rate etc in the state quantity of each wheel suspension so as to estimate and compute optimum target controlling force corresponding to the state quantity and physical quantity. taking the variation into account. CONSTITUTION:A state detection means I is provided for detecting physical quantity affecting a suspension characteristic, state quantity showing suspension movement, and state quantity showing vehicle running state. According to its output, a forthcoming variation in vehicle moving state is estimated to be computed by a state quantity variation estimate means I'. Then, forthcoming vehicle moving state is judged by a state judging means II01 according to outputs from the both means I, I', so that optimum target controlling force is computed by a target controlling force computing means II02 according to outputs from the both means I, II01. Furthermore, detection controlling force, corresponding to the physical quantity is computed by a detection controlling force computing means II2, and a deviation between the detection controlling force and the target controlling force is computed by a deviation computing means II3. According to the deviation, an actuator means IV is driven via a driving means III so as to control a suspension characteristic.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a support device for a building or a traveling device,
The present invention relates to a vibration control device when vibration is generated due to external force or disturbance (road surface).

(Prior Art) The inventors of the present invention first proposed a method for reducing the consumption of a suspension of a vibrating body, with the aim of suppressing or damping vibration when vibration is caused by an external force or disturbance. Calculates the target control force to achieve the optimal state based on the change in state quantity due to the vibration of the vibrating body due to energy,
We have developed a device that controls the damping force of the suspension of the vibrating body to follow the target control force, improving the vibration characteristics and reducing the amount of vibration of the vibrating body (Japanese Patent Laid-Open No. 108319/1983).
As shown in Fig. 2, the vibration control device disclosed in the above publication detects physical quantities that affect the characteristics of the suspension that supports the vibrating body, and also includes a state detection means (■) that indicates the movement of the suspension, and a control means (■). , a drive means (■) for power amplifying the output signal of the control means (■), and an actuator means (2) for continuously variable control of the characteristics of the suspension based on the output of the power amplification means (■), taking into account external forces or disturbances acting on the suspension. Since the characteristics of the suspension are continuously variably controlled so as to equivalently generate a control force according to the difference between the target control force and the detected control force, the target control force is equivalently added to the suspension as a result. This suppresses vibrations.

This conventional vibration control device can finely control physical quantities by considering external forces or disturbances, reduces energy consumption, has a simple configuration, and has a power source.

This reduces the weight, space, and cost of piping, etc.

(Problems to be Solved by the Invention) However, since this conventional device calculates the target control force based on the amount of change in the state quantity of the vibrating body, it has the following problems. Namely.

(1) Since the control is performed in response to a change in the state quantity, there is a time delay in the control for detecting a change, and the control does not start quickly in response to a sudden change in the state.

(2) Vibration control is performed for each suspension, and it is not possible to predict changes in state quantities assuming the overall movement of the vehicle, so the ability to follow related movements is extremely low.

It is an object of the present invention to solve these problems and to significantly improve the vibration response characteristics of a vehicle to excessive inputs such as external forces such as road protrusions and steps, and disturbances caused by gusts of wind when the vehicle is running.

(Means for solving the problem) The present invention comprises a state detection means (■), a state quantity change prediction means (■'),
It is equipped with a control means (2), a drive means (2), and an actuator means (2).

That is, the state detection means (2) detects physical quantities that affect the characteristics of the suspension that supports the vehicle, and also detects the state quantities that indicate the movement of the suspension and the state quantities that indicate the running state of the vehicle, and the state quantity change prediction means. 2' is for predicting a change in the vehicle's moving state to come based on the state quantity indicating the vehicle's running state up to the present detected by the state detecting means I by a predetermined calculation.

The control means (■) determines the upcoming motion state of the vehicle from the current state quantity detected by the state detection means (I) and the amount of change in the upcoming state quantity of the vehicle predicted and calculated by the state quantity change prediction means (■'). ■ State determination means. , and state detection means! Detected physical quantities and state determination means■. Target control force calculating means ■ which calculates an optimal target control force based on the upcoming motion state of the vehicle determined by . 2, a detected control force calculation means ■2 that calculates a detected control force corresponding to the physical quantity detected by the state detection means I, and a deviation calculation means ■3 that calculates the deviation between the target control force and the detected control force. This is what happens.

The driving means (2) is for power amplifying the deviation signal between the two control forces which is the output of the control means (2).

Based on the power amplified output, the actuator means continuously adjusts the characteristics of the suspension in order to generate a control force isometrically according to the deviation of the actual detected control force from the target control force that takes into account external forces or disturbances acting on the suspension. It is controlled variably.

Then, by these means, the degree of change in the state quantities of the entire vehicle and the suspension of each wheel is determined.

By predicting the amount of change in the vehicle's state quantity that will come, and calculating the optimal target control force according to the state amount and physical quantity that take this change into account, the optimal target that corresponds to the vehicle's upcoming motion state can be determined. It generates a control force to continuously and optimally control the characteristics of the suspension.

According to an embodiment of the present invention, the state quantity change prediction means determines the correspondence between the state quantity indicating the current driving state detected by the state detection means and the control quantity determining the state of the vehicle. Based on this, the system is configured to predict and calculate a change in the upcoming motion state of the vehicle.

(Operations and Effects of the Invention) The operations and effects of the present invention having the above configuration are as follows.

The time-series optimal target control force U that takes into account the vibration of the vibrating body caused by external force or disturbance acting on the suspension that supports the vibrating body m is based on the assumption of active control.
For example, the slow motion equation in FIG. 3 is as follows.

m^=u(x, λ, "X") ・・・・・・・・・・・・
・・・・・・・・・(1) However, X is the suspension displacement due to external force or disturbance, ÷ is the suspension speed, ^
is the acceleration given to the vibrating body. That is, eye 41
Il! The control force U is a function of X,;,^.

Here, the target control force U can be further expressed in a general form as follows.

Here, g is the contribution gain coefficient for providing optimal vibration suppression, and X is all the S quantities that can describe the vibration system, including the suspension displacement, speed, and acceleration mentioned above. This usually includes transmission between various parts of the suspension. In other words, the optimal target control force U is determined by instantaneously detecting the state physical quantity X of the vibrating body m and giving a coefficient gl depending on the contribution of each component, thereby configuring a so-called instantaneous state feedback control system. It is possible to provide optimal vibration suppression to a mass vibration system.

On the other hand, in the optimum gain setting section of one or more instantaneous state feedback control systems, the setting gain is determined based on the signal obtained by the state quantity change prediction means that predicts the state quantity or the next change in the state quantity. and the temporal timing of subsequent gain adjustment can be controlled.

With respect to this target control force U, the physical quantity f acting on the suspension is detected by the sensor in the state detection means ■, and the deviation ε (= u − f) is calculated by the deviation calculation means ■3, and its output is The power is amplified by the drive means (2), and the actuator means (2) attached to the suspension is driven to continuously control the physical quantity f.

In other words, by extracting the force related to the physical quantity f from the optimal target control force u (x, λ, 'x'') and controlling that physical quantity, it is possible to achieve more fine-grained vibration control effects in consideration of external forces or disturbances than with conventional vibration control effects. It is possible to control the physical quantity f, reduce energy consumption, simplify the configuration, and reduce the weight, space, and cost of power sources, piping, etc.

In this way, in the present invention, the state quantity change prediction means ■'
The state determination means (■) within the control means (2) predicts the change and response of the state quantity due to the vibrating body, or predicts the scale of external force or disturbance to the vibrating body. By accurately modifying the optimal target control force of the vibrating body in anticipation of the amount of change in the upcoming state quantity, the vibration control effect can be significantly improved.

That is, by suddenly changing the optimal gain coefficient value when calculating the optimal control target force to a preset value according to the predicted state quantity change prediction value, and increasing or decreasing the optimal target control force as necessary.

Vibration due to external force or disturbance to the vibrating body can be significantly reduced.

As described above, the present invention can significantly improve the vibration response of a vehicle to excessive inputs such as external forces such as a two-step difference in road surface bumps and disturbances caused by gusts of wind when the vehicle is running.

(Example) A schematic configuration diagram of an example of the present invention is shown in FIGS. 3(a) and (
Shown in b). Further, FIG. 4 is a block diagram showing an electronic control device that controls the control device shown in FIG. 3(b).

In these figures, 1 indicates a reserve tank that stores oil as a working fluid, and 2fr, 2fl
, 2rr, and 2rl indicate actuators provided corresponding to the right front axle, left front wheel, right rear wheel, and left rear wheel of the vehicle, which are not shown in the figure, respectively. As shown in FIG. 3(a), each actuator consists of a cylinder 3 and a piston 4, which are respectively connected to the vehicle body and suspension arm, and has a cylinder chamber 5 defined by these as a working fluid chamber. By supplying and discharging oil to and from the vehicle, it is possible to increase or decrease the vehicle height at the corresponding location. Note that the actuator increases or decreases the vehicle height at the corresponding position by supplying or discharging a working fluid such as oil to the working fluid chamber, and the pressure within the working fluid chamber increases or decreases in response to wheel bounce and rebound. Any device, such as a hydraulic ram device, may be used as long as it is configured as such.

The reserve tank 1 includes an oil pump 6°, a flow control valve 7, an unload valve 8. A conduit 10 with a check valve 9 communicates with the branch point 11 .

The pump 6 is driven by the engine 12, so that
Oil is pumped up from the reserve tank 1 and high-pressure oil is discharged, and the flow rate control valve 7 is configured to control the flow rate of the oil flowing in the conduit 10 on the downstream side. The unload valve 8 detects the pressure in the conduit 10 downstream of the check valve 9, and when the pressure exceeds a predetermined value, returns the oil to the conduit 10 upstream of the pump 6 via the conduit 13. The pressure of the oil in the conduit 10 on the downstream side of the check valve 9 is maintained below a predetermined value. The check valve 9 is configured to prevent oil from flowing backward in the conduit 10 from the branch point 11 toward the unload valve 8.

The branch point 11 is provided with a check valve 14 and a 15° electromagnetic on-off valve 16 and 17, respectively. Conduits 20 and 21 with electromagnetic flow control valves 18 and 19 communicate with the cylinder chambers 5 of the actuators 2fr and 2fl. Further, the branch point 11 is connected to a branch point 23 by a conduit 22, and each branch point 23 has a check valve 2 in the middle.
4 and 25. Electromagnetic on-off valves 26 and 27. Conduits 30 and 31 with electromagnetic flow control valves 28 and 29 are connected in communication to the cylinder chambers 5 of actuators 2rr and 2rl, respectively.

Thus, actuators 2fr, 2fl, 2rr
.

The cylinder chamber 5 of 2rl has conduits 10.20 to 22.3.
Oil is selectively supplied from the reserve tank 1 through 0°31, and in this case, the oil supply and its flow rate are controlled by on-off valves 16, 17, 26, respectively, as will be explained in detail later. 27 and flow control valve 18.
19.28.29 is controlled as appropriate.

Flow control valves 18 and 1 in conduits 20 and 21, respectively
9 and the actuators 2fr and 2fl are connected to a return conduit 38 communicating with the reserve tank 1 through conduits 36 and 37 having electromagnetic flow control valves 32 and 33° electromagnetic on-off valves 34 and 35, respectively, in the middle. has been done. Similarly, the portions of conduits 30 and 31 between flow control valves 28 and 29, respectively, and actuators 2rr and 2rl include electromagnetic flow control valves 39 and 40, respectively, in the middle. Conduits 43 and 44 having electromagnetic on-off valves 41 and 42 communicate with the return conduit 38.

Thus, actuators 2fr, 2fl, 2rr
.

The oil in the 2rl cylinder chamber 5 is selectively discharged to the reserve tongue 1 via conduits 36 to 38° 43, 44, and the oil discharge and flow rate in this case will be detailed later. As explained, each on-off valve 3
4.35.41.42 and flow control valve 32°33,3
9.40 is controlled as appropriate.
In the illustrated embodiment, the on-off valves 16.17°26,2
7.34.35.41.42 is a normally closed on-off valve,
When the corresponding solenoid is not energized, the valve is kept closed to cut off communication with the corresponding conduit as shown in the diagram, and when the corresponding solenoid is energized, the valve is opened to take action. It is designed to allow communication of conduits. Also, flow control valve 18.19.28.29.3
2.33.39.40 changes the degree of throttling by changing the duty of the voltage or current of the drive current energized to the corresponding solenoid, and thereby,
Corresponding conduit - Controls the flow rate of oil flowing inside.

The conduits 20, 21, 30, 31 each have a check valve 14.
Accumulators 45 to 48 are connected in communication at positions upstream of the angles 15 and 24.25. Each accumulator has an oil chamber 4 separated from each other by a diaphragm.
9 and an air chamber 50, it compensates for pressure changes in the conduit 10 due to oil pulsation caused by the pump 6 and the action of the unload valve 8, and the corresponding conduits 20, 21, 30, 31
It has a pressure accumulating effect on the oil inside.

Flow control valves 18 for each of the conduits 20.21.30.31
Main springs 59 to 62 are connected to the portions between ゜19 and 28.29 and the corresponding actuators by conduits 55 to 58 having variable throttle devices 51 to 54 in the middle, respectively. The secondary spring 7 is connected to the portion between each of the variable throttle devices 58 and the main spring by conduits 67 to 70 having normally open on-off valves 63 to 66 in the middle.
1 to 74 are connected. The main springs 59 to 62 each have an oil chamber 75 separated from each other by a diaphragm.
and an air chamber 76, and similarly sub-springs 71 to 7.
4 consists of an oil chamber 77 and an air chamber 78, which are separated from each other by a diaphragm.

Thus, as shown in FIG. 3(a), when the volume of the cylinder chamber 5 of each actuator changes as the wheels bounce and rebounce, the cylinder chamber and oil chamber 7
The oil within 5.77 flows through the variable throttling devices 51 to 54 and the vibration damping effect is exerted due to the flow resistance at that time. In this case, the degree of throttling of each variable throttling device is controlled by the corresponding motors 79 to 82, so that the damping force C is continuously and steplessly switched, and the on-off valves 63 to 66 are selectively opened and closed by the corresponding motors 83 to 86, respectively, so that the spring constant K can be switched between high and low levels. The motors 79 to 82 and the motors 83 to 86 are used for vehicle nose dive, squat,
In order to reduce the roll, as will be explained later, the vehicle speed sensor 9
5. Steering angle sensor 96. Throttle opening sensor 97. f
It is controlled by an electronic control device 102 based on a signal from the f1lJ motion sensor 98.

Furthermore, each actuator 2fr, 2fl, 2rr.

Vehicle height sensors 87 to 2rl are located at positions corresponding to 2rl, respectively.
90 are provided. These vehicle height sensors.

By measuring the relative displacement between the cylinder 3 and the piston 4, or a suspension arm (not shown), the vehicle height at the corresponding position is detected, and a signal indicating the vehicle height is generated as shown in FIG. It is configured to output to the electronic control unit 102 shown.

The electronic control unit 102 includes a microcomputer 103, as shown in FIG. The microcomputer 103 may have a general configuration as shown in FIG.
) 104, a read-only memory (ROMHO5), a random access memory (RAM) 106, an input port device @107, and an output port device 108, which are connected to each other by a bidirectional common bus 109.

The input boat device @107 indicates whether the vehicle height is high (H), normal (N), or low (L), which is selected from a vehicle height selection switch 110 provided in the vehicle interior and operated by the driver. A switch function signal indicating whether the The input port device 107 also stores actual vehicle heights Hfr, Hfl, and Hrr detected by vehicle height sensors 87, 88, 89, and 90, respectively.

Signal indicating Hrl, vehicle speed sensor 95. Steering angle sensor 96
゜Throttle opening sensor 97. Vehicle speed V and steering angle δ (right turn is positive) respectively detected by brake sensor 98.

Signals indicating the throttle opening θ and the braking state are sent to the corresponding amplifiers 87a to 90a, 95a to 99a, and the multiplexer 111. The signal is input via an A/D converter 112.

The ROM 105 stores reference vehicle heights Hhf and Hhr as target vehicle heights for the front wheels and rear axles when the vehicle height selection switch 110 is set to high, normal, or low;
Hnf and Hnr, HIf and Hlr (Hh
f>Hnf>Hlf, Hhr>Hnr>Hlr). Based on the calculation results, the CPU 104 sends the output port device 108 to the on-off valve and flow control valve provided corresponding to each actuator. 118 corresponding to each
a to 118h, a motor 79 that selectively outputs control signals via amplifiers 119a and 119h and 120a to 120h, and also drives the variable aperture devices 51 to 54;
~82 and a motor 83~ that drives the on-off valves 63-66
Go to 86.

Output boat device 108. Corresponding D/A converters 121a to 121h and 123 to 123h, respectively
, amplifiers 122a-122h and 124a-12
After 4 h, a control signal is selectively output.

The display 116 connected to the output port device 108 includes:
The reference vehicle height selected by the vehicle height selection switch 110 is
Whether it is high, normal, or low is displayed.

Next, the operation of the apparatus according to the embodiment of the present invention shown in FIGS. 3(b) and 4 will be explained with reference to the flowchart shown in FIG.

First, initial settings are made in step P1, and then step P
In step 2, signals from each sensor shown in FIG. 4 are read.

Next, a predictive calculation of the vehicle state quantity (step P2□) is performed. Here, signal processing is performed from the sensors related to (1) acceleration, (2) deceleration, (2) road surface bumps, and (3) steering roll, and an arithmetic expression or map is prepared for calculating a prediction of changes in vehicle state quantities.

The relationship of state change predictions for the above states (1) to (2) is shown in the following table.

A map representing the relationship between the predicted motion state change f, the state quantity V indicating the running state, and the control amount α determining the vehicle state is determined in advance through experiments. An example is shown in FIG. It should be noted that each of these maps can be approximated by the following equation, and therefore predictive calculation may be performed using this equation.

f I :=czv Ca, +av+b, a+a
, v-d1) However, alp t) I+ Ox d+ is a constant.

Next, calculation of vehicle state quantities (step P3) is performed.

In other words, the state quantity sensor, which will be described later, is attached to each of the four suspension systems of the vehicle, which changes from time to time.

A vehicle state quantity is calculated by a predetermined calculation.

Next, the driving state of the vehicle is determined (step P4).

Here, it is determined whether the vehicle is in a running state,
If the vehicle speed is below a predetermined speed, the damping valve position is initialized (step ps) - On the other hand, after determining that the vehicle is in a running state, in steps P6 to P, It is determined whether the vehicle is in a state of overcoming or a state of deceleration.

Next, based on each determination, in step Pg, an optimal gain for calculating the target control force is calculated according to the predicted state. Here, the optimum gain may be calculated in advance for each case and stored in the memory map.

Next, in any of the determinations from Steps P6 to PIl□, if the state quantity predicted calculation value does not exceed the threshold value, then in Step P1°, the optimum gain of the control target force of each import arm is calculated. Here, the optimum gain may be calculated in advance for each case and stored in the memory map.

Next, the optimal gains obtained in steps P, P1o are added to calculate the optimal gain (step P□1).

Hereinafter, the determination is made in steps P21 and P6 to Po. A mechanism for predicting and determining driving conditions will be explained.

Acceleration determination (step PG) is performed using the throttle opening sensor 9.
Find the signal of 7 or the value obtained by differentiating the sensor signal,
When the value exceeds a predetermined value, it is determined that the acceleration state is entered.

Next, the steering determination (step p t ) is performed by the vehicle speed sensor 9
Based on the differential value of the signal 5 and the signals of the steering angle sensor 96 and the steering angle sensor 96, the steering turning state is determined when the value exceeds a predetermined value based on the predicted roll angle determined for the three types of signals. It is judged that it falls within the range.

Next, in the protrusion level difference determination (step P), when the front road surface sensor 94 exceeds a predetermined value, it is determined that the protrusion level difference state is entered.

In addition, the deceleration determination (step P81) is performed by the brake sensor 98.
The signal or a value obtained by differentiating the signal is determined, and when the value exceeds a predetermined value, it is determined that the deceleration state is entered.

Here, the control system for the control corresponding to the protrusion level difference will be explained using FIG.

Protrusion step recognition signal 1xo. , 1, when a protrusion level difference greater than the threshold is recognized, next, the vehicle speed V and the distance of the sensor from the front wheel are determined as 0. Time t1t determined from wheel base L
Set tz (tx=4!/v, t2==L/V).

Next, the state feedback gains for the front two wheels and the rear two wheels are
As shown in the timing chart in FIG. 6, the current gain is switched to the KFII gain in the figure, to the □ gain, and then to the current gain.

That is, when the front two wheels and the rear two wheels each ride on a protrusion step, the gain coefficient of the state quantity is set low.

After passing over the vehicle, the gain coefficient of the state quantity is set high to increase damping, reduce the vibration level transmitted by impact,
This speeds up the damping of sprung vibrations after impact.

In other words, the content of the state feedback gain is controlled in accordance with the driving state of the vehicle so as to match the predicted driving state.

The principle of how the wheel portion of the control device of the present invention is controlled by the drive signal obtained as described above will be explained. In the embodiment shown in FIG.
4. ROM105. For convenience of explanation, in FIG. 7, state quantity change prediction means I' and state determination means (2) are executed by a microcomputer consisting of a RAM 106 and the like.

1 and the gain selector are shown being processed by microcomputer 70.

As shown in FIG. 7, the state detection means (2) is a suspension arm 2 that rotatably supports the wheels of the suspension.
62 and the vehicle body frame 263 to detect relative displacement; and an amplifier 220 connected to the potentiometer 210 and outputting a signal representing the relative displacement y between the axle and the vehicle body when the vehicle is running.
, a differentiator 230 that differentiates the relative displacement y output from the amplifier 220 to detect the relative velocity n, and the hydraulic cylinder 110
A pressure sensor 211a is attached to the chamber to detect the acting wheel load, an amplifier 221a is attached to the inlet of the oil chamber of the accumulator 320 and is used to detect the damping force. Sensor 211b
, an amplifier 221b that is connected to the pressure sensor 211b and amplifies its output, a differential amplifier 231 that detects the damping force fc as the difference between the output of the amplifier 221b and the output of the amplifier 221a, and a differential amplifier 231 that is attached to the vehicle body to measure acceleration. An acceleration sensor 212 that detects, an amplifier 222 that is connected to the acceleration sensor 212 and amplifies it, an integrator 232a that integrates the output to detect the sprung mass velocity x2, and further integrates the output to detect the sprung mass displacement x2. an integrator 232b that detects
Attached to the gas chamber of the accumulator 320, the gas temperature t
a temperature sensor 213 that detects the temperature sensor 213, an amplifier 223 that is connected to the temperature sensor and amplifies the sensor output, the aforementioned vehicle speed sensor 214 that is attached to the output shaft of the automobile transmission and detects the vehicle speed V, a displacement sensor 256, and a displacement sensor 213 that detects the vehicle speed V. and an amplifier 224 that outputs a signal representing. The displacement sensor 256 detects the displacement of a spool 258 that continuously opens and closes an oil passage 350 to form a variable orifice in an actuator means (2) consisting of a linear actuator 255 and a valve body 259 as shown in FIG. 9(b). This is to detect.

State quantity change prediction means I' and state determination means ■. 1 is an input unit 271 that receives the vehicle speed V, relative displacement y, axle load W, and gas temperature t, and an arithmetic process that predicts changes in state quantities and discriminates states based on the inputs, and selects the optimal gain. 272, a storage unit 273 that stores each calculation method of the optimum gain and calculation processing unit 272, constants necessary for calculation, etc. in advance, and an output unit 274 that outputs the optimum gain selected by the calculation processing unit 272. It consists of a microcomputer 270 configured. In the embodiment shown in FIG. 4, the target control force calculation means (2). 2. The deviation calculation means n a is changed to the sign adjustment means ■4. Other arithmetic units are also configured by the functions of a microcomputer.

The functions performed by the microcomputer 270 corresponding to each of the four wheels will be explained in detail along the flowchart of FIG.

Replace the wheel suspension with a linear two-degree-of-freedom model in advance, assuming the active control suspension,
Using the linear square form optimal control method, relative displacement y, relative velocity ton, sprung mass displacement x z t sprung mass velocity λ2 . Optimal gains 01 to G for the damping force fc are calculated, read out from the storage section 273 and outputted from the output section 274.

Target control force calculation means■. 2 is the optimum gain G□ output from the output section 274 of the microcomputer 270.
.about.G and the corresponding state signal according to a linear equation, each shaft muscle has five multipliers 241 to 245 and an adder 250 for calculating the optimal target control force U.

That is, if the optimal target control force for the first to fourth wheels is uit u2t u3t u4, then the following equation is obtained.

u 1= (G 11 + Kti) '/ 10 (Gt
z + Kzz) V + G 13X2+G, 4x,
+ (1. to G1s+) fcua = (Gzt+Kzx)y
+(GB+Kzz))' +G2Jx.

1024X2+(G2s+,,)fCus=(G
3t + K13) '/ + (G32 + Kt*
Bow + G3jX2+G, 4x, + (G 1z +) f
cu4= (G4t + Kz4)3' + (G41
+ KzJ 3' + G43 X2+G, 4x, +
(For G4s+,) fc On the other hand, sprung vibration model (bounce pitch.

pitch roll), it can be written as linear depending on how the symbols are taken.

u, = G1□y + Gxzy + (Gta + Kx
t)Xt*+ (G14 + Kxz)Xxz+CGx
s+Kxs) fxcu2=G, 1V +G22'/
+ (Gz2+Kzx) Xzz+ (G24+ K2
2) =zz + (Gzs + Kzs) f 2Gu
a=Gazy+GizM+(Gaa+Ka1)Xaz
+ (G34+ K23) X32 + (03s +
Kts) f 3Gu4=G4, y+G4z:/+(
G4a+ to 4i)X4z+(G4*+Kz,)X4z+
(04s”Kzs)f*c This is generally expressed as follows and will be explained below.

u=G1・y+G2・y+G,・X2 +G4・λ2+G,・fc ・・・・・・・・・・・・
...(3) The deviation calculation means ■ calculates the deviation ε between the damping force fc to be controlled and the optimal target control force U output from the optimum target control force calculation means ■□3. It consists of a deviation device 251.

The sign adjustment means (2) consists of a multiplier 252 that multiplies the output ε of the deviation device 251 by the suspension relative speed n.

When performing damping force control according to the deviation ε with respect to the target control force U, the multiplier 252 determines whether or not the deviation ε with respect to the target control force can be controlled by the damping force, and if controllable, Outputs a signal that determines the direction of increase or decrease of damping force,
Furthermore, if control is not possible, the damping force is reduced and a signal is output in a direction that approaches zero.

The sign adjustment function of the multiplier 252 will be explained using the table and FIG. 9. When the target control force U is positive in the upward direction perpendicular to the vehicle body, and the relative speed of the suspension is positive in the direction of contraction of the air-liquid suspension, both the target control force U and the relative speed my are the same. For example, when the piston of the hydraulic cylinder 310 moves upward (positive direction) and the target control force U also moves upward (positive direction), the oil in the hydraulic cylinder 310 moves through the orifice 330 in proportion to the relative speed. As the gas flows into the liquid-air fluid spring 120,
By changing the opening degree of the orifice 330 using a control signal, it is possible to change the pressure within the hydraulic cylinder 310, that is, the magnitude of the upward damping force fc (positive direction) of the damping coefficient. In this case, the output ε of the deviation device 251 is positive (
When ε is negative (u<fc), the orifice opening is set in the closing direction and the damping coefficient is increased to increase the damping force; when ε is negative (u<fc), the orifice opening is set in the closing direction and the damping coefficient is reduced to reduce the damping force. What is necessary is to output a control signal that causes the Further, the piston of the hydraulic cylinder 210 moves downward (negative direction),
When the target control force U is also downward (negative direction), contrary to the above, oil flows from the gas-liquid fluid spring 320 to the orifice 33.
0 and flows into the hydraulic cylinder 310, the magnitude of the downward (negative direction) damping force fc can be changed by similarly controlling the orifice opening degree. In this case as well, when ε is positive (-u)-fc), the orifice opening is set in the open direction, the damping coefficient is made small, and the damping force is reduced.
If E is negative (-u(fc)), it is necessary to set it in the closing direction and output a control signal that increases the damping coefficient and increases the damping force that equivalently acts on the suspension. Therefore, the target control force U When the relative speed of the hydraulic cylinder 310 and the relative speed of the hydraulic cylinder 310 are in the same direction, the damping force fc can be controlled based on the target control force U.On the other hand, when the target control force U and the relative speed of the suspension are in the opposite direction, for example, when the piston of the hydraulic cylinder 310 is upward (
positive direction) and the target control force U is downward (negative direction), the oil in the hydraulic cylinder 310 flows into the orifice 33.
Since the gas flows into the gas-liquid fluid spring 320 through 0, the orifice opening degree is kept at a certain degree (not controlled).
Then, an upward (positive direction) damping force acts together with the relative speed, making it impossible to control the damping force based on the target control force U.

Therefore, if the orifice opening degree is fully opened by the control signal, the damping coefficient is minimized, and the damping force fc in the positive direction that equivalently acts on the suspension is reduced, it will be as if the damping force fc in the case of no control is controlled by the target control. This corresponds to applying a force in the direction of force U and reducing it. At this time, the output ε (=u−fc) of the deviation device 51 is positive because the target control force U is negative and fc is in the same direction as the relative speed N, so it is always negative.

Furthermore, even when the piston of the hydraulic cylinder 310 moves downward (negative direction) and the direction of the target control force is upward (positive direction), the damping force is controlled based on the target control force U in the same way as above. Therefore, it is desirable to use a control signal to fully open the orifice and minimize the damping coefficient, thereby reducing the damping force equivalently acting on the suspension. Output 5 of the deviation device 51 at this time (=u-fc)
is negative because the target control force U is positive and fc is in the same direction as the relative speed n, so it is always positive. Therefore, when the target control force U and the relative speed are in opposite directions, eye 4M
Since it is not possible to control the damping force based on the m control force U, it is sufficient to fully open the orifice and reduce the damping force using the control signal.

As described above, the control direction of the damping force and the orifice opening degree with respect to the output ε of the deviation device 251 in each state is summarized as shown in the table. In order to basically achieve this logic, by multiplying the sign of ε by the sign of the suspension relative velocity which is in the same direction as the damping force, the output is a control signal corresponding to the control direction of the orifice opening. becomes. Here, it is sufficient that the control signal determines the direction of increase or decrease of the damping force, and in order to improve the ratio of noise to the deviation ε signal with respect to the target control force, that is, the S/N ratio, the multiplier 252 is used to directly compensate ε. The control signal was ε, which is the sum of the speed and the value of .

Integrating means (2) consists of an integrator 253 composed of an operational amplifier, a resistor R that determines an integral gain, and a capacitor C, and integrates the output ay of the multiplier 252 over time to obtain the target control force U.
In order to eliminate the offset (residual deviation) of the deviation ε from the damping force fc, the damping force of the suspension is detected,
In addition to feeding back and using it as an integral input, from the viewpoint of control system responsiveness and stability, integral gain K11 (=
1/CR) was set to K K = 2400. In addition, in order to prevent the integrator from drifting itself, its output was feed-packed to the input using a resistor.

The drive means (2) comprises a drive circuit 54 which provides negative feedback of the spool displacement signal of the actuator means (2) to the output of the integrator 253 and outputs a current proportional to the deviation signal.

The actuator means (■), as shown in FIG. 9(b),
Hydraulic cylinder 310 of the gas-liquid fluid suspension attached to the suspension arm 262 and the vehicle body frame 263
A valve body 259 is integrated with the valve body 259, an oil passage 350 communicates the oil chamber of the accumulator 320 and the oil chamber of the hydraulic cylinder 310 through the valve body 259, and the oil passage 350 is continuously opened and closed to form a variable orifice. A moving coil 257 of a linear actuator 255 integrated with the spool, and a permanent magnet 260 that applies a force to the moving coil in accordance with the current output from the drive circuit 254 flowing through the moving coil.
, a displacement sensor 256 that is attached to the linear actuator 255 and detects the displacement of the spool in order to suppress the force acting on the moving coil, and an amplifier 224 that outputs a signal representing the displacement.

Using FIG. 10, the movement of the spool with respect to /Eydt, which is obtained by time-integrating the output ε of the multiplier 252 of the control means (2), which is the control input of the actuator means, will be explained. In Fig. 10, the horizontal axis shows the control input fEydt, and the vertical axis shows the spool displacement X and the damping coefficient C for the orifice opening a and the spool displacement. When the spool displacement signal is zero, the spool displacement signal is fed back to the drive circuit to maintain the spool displacement X at a neutral position (0%), and provides an orifice opening degree, that is, a damping coefficient C, that satisfies riding comfort. The value of the damping coefficient C at that time is a zero-order function of the relative velocity of the suspension, and the control input is also positive (+/εydt) for the positive output (+ε:/) of the multiplier 252. , spool displacement X, moves the oil passage 350 from the neutral position in the direction of fully closing (x1 = -100%) according to ε, reduces the orifice opening a, and increases the damping coefficient C to increase the damping force. let

In addition, for the negative output (-ay) of the 1 multiplier 52, the control input also becomes negative C-fεyat), so the spool displacement
, fully opens the oil passage 350 from the neutral position according to ξn (x,
=+100%) direction, the orifice opening degree a is increased, and the damping coefficient C is lowered to reduce the damping force.

The operation of this embodiment is as follows.

In response to external force or disturbance from the road surface, the microcomputer 270 outputs the output V of the vehicle speed sensor 214 and the amplifier 22.
Based on the axle load W detected at 1a, the relative displacement y detected by the linear potentiometer, and the gas temperature t detected by the temperature sensor 213, the relative displacement y, relative speed n, sprung mass displacement x2. The adder 250 outputs the optimum gains G□ to G5 for the sprung speed Xtl and the damping force fC, and outputs the optimum target control force U calculated based on the equation (3) above. The deviation between the output of this target control force U and the damping force fc to be controlled is taken, and the deviation is multiplied by the relative speed using a multiplier 52 to convert it into a control signal for the damping force. Integrator 53. Each time a current is applied to the linear actuator 55 via the drive circuit 54 and the spool 58 is moved, the damping coefficient changes, and the damping force fc can be continuously changed.

The apparatus according to the embodiment of the present invention has the above-mentioned function.

Since the optimum gain can always be selected in the air-liquid fluid suspension and the damping force fc is continuously controlled based on the signal of the optimum target control force U calculated thereby, it is possible to adapt to all driving conditions, and as a result, This has the advantage that ride comfort, running stability, etc. can be greatly improved.

In addition, the multiplier 252 of sign adjustment means (4) calculates the product ε of the deviation ε with respect to the target control force and the relative speed i of the suspension.
Since the signal level increases compared to the deviation ε, the signal-to-noise ratio.

In other words, a control signal ε with a good S/N ratio can be obtained.

Furthermore, an integrator 53 that integrates the signal over time integrates the fluffy component (0, 2) 1 of the sprung mass vibration that affects the riding comfort.
It is possible to eliminate offsets (residual deviations) that are harmful to controlling z~27) to an optimal vibration level.

Therefore, it is possible to control the damping force in accordance with the fluffy component of the target control force U, and at the same time achieve the optimum vibration level.
The gain is small for high-frequency noise that adversely affects damping force control, but the gain is sufficiently high for the frequencies required for vibration control, so it has the advantage of improving the stability of the control system. be.

Moreover, the actuator means (■) for controlling the damping force fc is
Instead of using a return spring to respond to the force generated by a linear actuator, the displacement of the spool is fed back, so the spool can be moved with a small amount of electrical energy, making effective use of the generated force. It has improved responsiveness and can control even minute vibrations with a high frequency, and does not require power sources such as hydraulic power or pneumatic sources, which reduces the weight and space of piping.

This has the advantage of reducing costs.

Note that although the multiplier 252 is used in sign adjustment means (2) of the present invention, a divider may also be used.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of the present invention, and FIG. 2 is a block diagram showing the prior art. FIG. 3(m) is a diagram showing the position of the suspension in a vibration control device of an embodiment in which the present invention is applied to an automobile, FIG. 3(b) is a diagram showing an outline of the control mechanism of the embodiment, and FIG. A block diagram showing an electronic control device that controls the control mechanism shown in FIG. 3(b), FIG. 5 is an operation flow diagram for explaining the operation of this embodiment, and FIG. A diagram for explaining the operation. FIG. 7 is a diagram for explaining the control of the wheel portion in the embodiment of FIG. 4. 8 is an operation flow diagram showing the flow of the operation in FIG. 7, FIG. 9(a) is a schematic configuration diagram of an automobile gas-liquid fluid suspension according to an embodiment of the present invention, and FIG. 9(b) is a cross-sectional view of the actuator means. Figure 10 shows the control input, orifice opening, spool displacement,
A characteristic diagram showing the relationship between damping coefficients. FIG. 11 is a diagram showing an experimentally obtained map for state prediction. ■...State detection means, 1'...State quantity change prediction means, ■...Control means, ■. , . . . state determination means, ■, 2nd . . . JIA control force calculation means. ■2...Detection control force calculation means, ■...Difference calculation means, ■...Driving means, ■...Actuator means. Fig. 6 Fig. 9 (b) 255...Linear actuator 256...Friend position sensor 257...Moving carp It/ 258
°°゛Spool 259-)Y11/7'body'4
260” bc Hisa

Claims (2)

[Claims] (1) A state detection means for detecting physical quantities that affect the characteristics of the suspension that supports the vehicle, as well as state quantities indicating the movement of the suspension and state quantities indicating the running state of the vehicle, and a state quantity detected by the state detection means. a state quantity change prediction means for predicting a change in the upcoming motion state of the vehicle by a predetermined calculation from a state quantity indicating the running state of the vehicle up to the present time; a state determining means for determining the upcoming motion state of the vehicle from the amount of change in the upcoming state quantity of the vehicle predicted and calculated by the state quantity change predicting means; a physical quantity detected by the state detecting means and the state determining means target control force calculation means for calculating an optimal target control force based on the upcoming motion state of the vehicle determined by the vehicle; and detection control force calculation means for calculating a detected control force corresponding to the physical quantity detected by the state detection means. and a deviation calculating means for calculating the deviation between the target control force and the detected control force, a driving means for power amplifying a deviation signal of both control forces which is an output of the control means, and a power amplification. Actuator means for continuously variable control of suspension characteristics to equivalently generate a control force corresponding to the deviation of the actual detected control force from the target control force that takes into account external forces or disturbances acting on the suspension based on the detected output. From the degree of change in the state quantities of the suspension of the entire vehicle and each wheel, the amount of change in the state quantities of the vehicle to come is predicted, and the optimal target control force is calculated according to the state quantities and physical quantities taking into account the changes. A variable damping force suspension control device is characterized in that it generates an optimal target control force in accordance with the upcoming motion state of a vehicle by predictively calculating and continuously optimally variably controls suspension characteristics. (2) The state quantity change prediction means determines the upcoming motion state of the vehicle based on the correspondence between the state quantity indicating the current driving state detected by the state detection means and the control quantity determining the state of the vehicle. The variable damping force suspension control device according to claim 1, wherein a change in damping force is predicted and calculated.