JPH02163663A - Correcting device for acceleration detecting value of vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is directed to, for example, appropriately controlling a fluid pressure cylinder interposed between the vehicle body and each wheel according to the acceleration (lateral acceleration, longitudinal acceleration, etc.) generated in the vehicle body. The present invention relates to a correction device for an acceleration detection value used in an active suspension, etc., which actively suppresses changes in the posture of a vehicle body caused by the above-mentioned acceleration by controlling the above-mentioned acceleration. By eliminating this, control accuracy is improved.

E. Prior Art] As a conventional technology of this type, for example, the one described in Japanese Patent Application Laid-Open No. 1983-61134319 (named ``Vehicle Suspension Device'') proposed by the present applicant is known.

This conventional technology corrects the detected acceleration value of a vehicle used in active suspensions, etc., which appropriately changes the working fluid pressure of a fluid pressure cylinder installed between the vehicle body and each wheel according to the acceleration generated in the vehicle body. The device detects (9) a steady state in which no lateral acceleration or longitudinal acceleration is occurring in the vehicle (referred to as a non-acceleration state in the prior art described in Section 2).
For example, for lateral acceleration, when the vehicle is running straight, and for longitudinal acceleration, when the vehicle is running at a constant speed), the instantaneous output of each acceleration sensor in this steady state is This value is used as a correction value to correct the subsequent output value of each acceleration sensor, and the working fluid pressure of the fluid pressure cylinder of the active suspension is controlled according to the corrected acceleration detection value. Even if an output error such as a DC offset output is included in the detected acceleration value, good control can be performed without using a highly accurate and expensive acceleration sensor.

[Problem to be solved by the invention]

However, in the above conventional technology, when the vehicle is traveling straight (when the steering angle is in the neutral position for a certain period of time or more), the instantaneous output value of the lateral acceleration sensor is calculated by the offset amount of the lateral acceleration sensor. The configuration is such that this offset amount is used as a correction value for the detected lateral acceleration value, and when the vehicle is running at a constant speed (including a state where no braking or acceleration is being performed, and when the vehicle is stopped) The configuration was such that the instantaneous output value of the longitudinal acceleration sensor was determined to be the offset amount of the longitudinal acceleration sensor, and this offset amount was used as the correction value for the longitudinal acceleration detected value. Even a sensor will incorrectly judge that there is an excessive amount of offset if you are driving straight on a banked road, and similarly, even if a longitudinal acceleration sensor with a small offset amount is used, if you are driving straight on a slope, it will be incorrectly determined that there is an excessive amount of offset. If you do so, it will be incorrectly determined that there is an excessive amount of offset. Furthermore, the output values of the lateral acceleration sensor and longitudinal acceleration sensor fluctuate due to vibrations generated in the vehicle body. If it is determined, the instantaneous output value of the acceleration sensor at that time will be used as the correction value, so there is a possibility that the obtained correction value will be greatly influenced by instantaneous vibrations.

Therefore, in the above conventional technology, the correction value for the acceleration detection value is set to a value different from the actual offset amount of the acceleration sensor, and the subsequent correction of the acceleration detection value becomes meaningless. Changes in the posture of the vehicle body cannot be accurately reflected in the pressure fluctuations of the pressure cylinder, and for this reason, not only is it not possible to suppress changes in the posture of the vehicle body, but in some cases, it may even worsen the change in posture, making it impossible to achieve satisfactory control accuracy. It was difficult to obtain.

Furthermore, since an expensive steering angle sensor is required to detect straight-ahead running, there is also the drawback that the cost is high.

This invention was made by focusing on such unresolved problems in the conventional technology, and by obtaining an accurate correction amount, it is possible to reliably eliminate the offset amount of the acceleration detection means, thereby improving control accuracy. It is an object of the present invention to provide a correction device for a detected acceleration value of a vehicle that can improve the acceleration of a vehicle.

[Means for Solving the Problem] In order to achieve the above object, a correction device for a detected acceleration value of a vehicle according to claim (1) is provided, as shown in the basic configuration diagram of FIG. acceleration detection means for detecting acceleration occurring in the vehicle; steady state detection means for detecting a steady state in which the acceleration is not occurring in the vehicle; and steady state detection means for detecting the steady state when the steady state detection means detects the steady state. a correction value calculation means for calculating an average value of the acceleration detection values of the detection means as a correction value; a correction means for correcting the acceleration detection value of the acceleration detection means with the correction value calculated by the correction value calculation means; and this correction means. and a control means for outputting a command signal to a control target appropriately provided on the vehicle body in accordance with the detected acceleration value corrected in the above.

Further, as shown in the basic configuration diagram of FIG. 1(b), the device for correcting the detected acceleration value of a vehicle according to claim (2) is a device for detecting a vehicle speed according to the invention according to claim (1), as shown in the basic configuration diagram of FIG. In addition to providing a detection means, the steady state detection means includes a first determination means for determining whether or not a vehicle speed detection value of the vehicle speed detection means is equal to or higher than a predetermined vehicle speed; The second step to determine whether or not
a determining means, a low-pass filter into which the acceleration detection value of the acceleration detecting means is input, and a third determining means for determining whether a difference value between the input value and the output value of the low-pass filter is equal to or less than a predetermined difference value. and the above-mentioned No. 1. Steady state determining means determines that the vehicle is in a steady state when all the determination results of the second and third determining means are true.

Furthermore, the correction device for the detected acceleration value of a vehicle according to claim (3), as shown in the basic configuration diagram of FIG. 1(C),
In the invention as set forth in claim (2) above, there is provided a neutral position detecting means for detecting that the steering angle is at the neutral position, a throttle opening detecting means for detecting that the throttle opening is kept constant, and a throttle opening detecting means for detecting that the throttle opening is kept constant; At least one detection means is provided among the braking detection means for detecting that the braking is not performed, and the detection result of the provided detection means is true, and the judgment results of the first, second and third judgment means are all true. When true, the steady state determining means of the steady state detecting means determines that the vehicle is in a steady state.

[Effect]

In the invention described in claim (1), the correction value calculated by the correction value calculation means is the acceleration of the acceleration detection means when the steady state detection means detects a steady state (a state in which no acceleration is generated in the vehicle body). Since it is an average value of the detected values, noise components included in the detected acceleration value (components appearing in the detected acceleration value due to vibrations of the vehicle body, tilt of the vehicle, etc.) are attenuated.

Therefore, when the correction means corrects the acceleration detection value using this correction value, only the offset amount of the acceleration detection means is excluded from the acceleration detection value, so that the control means responds to the corrected acceleration detection value. Since the command signal is output to the controlled object, control accuracy is improved.

Further, in the invention described in claim (2), in the steady state detection means for detecting the steady state, the first determination means determines that the vehicle speed detection value of the vehicle speed detection means is equal to or higher than a predetermined vehicle speed, and the second
The determining means determines that the acceleration detected value of the acceleration detecting means is equal to or less than a predetermined acceleration, and the third determining means determines that the difference value between the input value and the output value of the low-pass filter to which the acceleration detected value of the acceleration detecting means is input is determined. When it is determined that the difference is less than or equal to the predetermined difference value, that is, the first difference is determined to be less than or equal to the predetermined difference value. When the determination results of the second and third determination means are all true, the steady state determination means determines that the vehicle is in a steady state (that is, the steady state detection means detects a steady state).

In the invention described in claim (3), the neutral position detecting means detects that the steering angle is at the neutral position, the throttle opening detecting means detects that the throttle opening is kept constant, and the vehicle. At least one detection means among the braking detection means for detecting that braking is not being provided is provided, and the detection result of the provided detection means is true and satisfies the same conditions as the invention described in claim (2) above. When you do,
The steady state determining means determines that the vehicle is in a steady state (that is, the steady state detecting means detects a steady state).

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

2 to 8 do not show a first embodiment of the present invention.

First, the configuration will be explained. In FIG. 2, IFL.

IFR, IRL, 1. RR is an active suspension as a controlled object that is interposed between the vehicle body side member 2 and the wheel side member 4 that individually supports each wheel 3FL, 3PR, 3RL, and 3RR, and each has a fluid pressure cylinder. Hydraulic cylinders 5FL to 5RR as
Coil springs 6FL to 6RR as elastic bodies and hydraulic cylinders 5FL to 51? It includes pressure control valves 7FL to 7111R that control the hydraulic pressure for R in response to a command signal from a control device 30, which will be described later.

Here, hydraulic cylinder 5F1. Each of ~5RR is
The cylinder tube 5a is attached to the wheel side member 4, the piston rod 5b is attached to the vehicle body side member 2, and the working oil pressure in the pressure chamber 19 closed by the piston 5c is applied to the pressure control valve 7F1. Controlled by ~7RR. Further, each of the coil springs 6FL to 6RR is connected to a hydraulic cylinder 5FL to 6RR between the vehicle body side member 2 and the wheel side member 4.
It is installed in parallel with 5RR to support the static load of the vehicle body. The coil springs 6FL to 6R) may have low spring constants that support the static load of the vehicle body.

The pressure control valves 7FL to 7[IR are supplied with a command signal from the control device 30 that outputs a command signal to suppress changes in the attitude of the vehicle body based on the lateral acceleration and longitudinal acceleration of the vehicle, and the current value of this command signal is Control pressures corresponding to the vehicle body are output, and these pressures are individually supplied to hydraulic cylinders 5FL to 5RR that constitute an active suspension inserted between each wheel and the vehicle body, thereby creating a biasing force that resists changes in the vehicle body posture. to occur. As shown in FIG. 3, the specific structure of the pressure control valve 7 includes a cylindrical valve housing 11 and a proportional solenoid 12 integrally provided therewith. A valve seat 11. of a predetermined diameter is provided in the center of the valve housing 11. Partition wall 11 with a. The upper insertion hole 11U in FIG. 2 defined by A and the lower insertion hole 1.1 in the same figure
．． L and are formed coaxially.

In addition, the insertion hole 1. A fixed throttle 13 is provided at the upper part of IL and at a lower position separated from the partition wall 11A by a predetermined distance, thereby forming a pilot chamber C between the fixed throttle 13 and the partition wall 1A. Further, a main spool 14 is disposed below the fixed throttle 13 in the insertion hole 11L so as to be slidable in its axial direction.
Feedback chambers F and FL are formed above and below the main spool 14, respectively, and the feedback chambers F are formed at the upper and lower ends of the main spool 14. , FL are regulated by offset springs 1.5A and 15B, respectively. Then, the input port lli control boat 11. is inserted into the insertion hole 11L.
n and drain boat llo are formed in communication in this order,
The input port lli is connected to the hydraulic oil supply side of the hydraulic power source 24 via the hydraulic pipe 25, the drain port 11o is connected to the drain side of the hydraulic power source 24 via the hydraulic pipe 26, and the control port h1. In is connected to the pressure chambers 19 of the hydraulic cylinders 7FL to 7RR via a hydraulic pipe 27.

The main spool 14 includes a land 14a facing the input port Ili&, a land 14b facing the drain port Ilo, and both lands 14a.

The pressure chamber 14c is formed of an annular groove formed between the pressure chambers 14b and a pilot passage 14d that communicates the pressure chamber 14c with the feedback chamber F on the lower side.

In addition, a poppet 16 is disposed in the upper insertion hole 11U so as to be slidable in the axial direction with the valve portion facing the valve seat 11a. The flow rate of the hydraulic oil flowing through the valve seat 11a, that is, the pressure in the pilot chamber C can be adjusted.

Furthermore, the input port lli is the pilot path IIs
The drain port 110 communicates with the insertion hole 11U via a drain passage 11t.

On the other hand, the proportional solenoid 12 includes a plunger 17 that is slidable in the axial direction, and a poppet 16 of the plunger 17.
It has an actuator 17A fixedly attached to the side, and an excitation coil 18 that drives the plunger 7 in its axial direction. It is appropriately excited by I. Thereby, movement of the plunger 17 controls the position of the poppet 16 via the actuator 17A, thereby controlling the flow rate passing through the valve seat 11a. Then, in a state where the pushing force by the proportional solenoid 12 is applied to the poppet 16, the feed bank chamber F11. When the pressures on both sides of Fu are balanced, the spool 14 is in the neutral position and the control boat lln
and the input port 111 and drain boat llo are cut off.

Here, the relationship between the current value I and the control oil pressure P output from the control boat in is as shown in FIG.
PMIN is output when is near zero, and when the current value l increases in the positive direction from this state, the control output P increases with a predetermined proportional gain of 1, and the line pressure of the hydraulic source 24 P MAX becomes saturated.

In addition, in FIG. 2, 28H is the pressure control valve 7F1, ~
7R1? The high pressure side accumulator 28I connected in the middle of the hydraulic piping 25 between the hydraulic pressure source 24 and the pressure control valve 7
FL~7RR and hydraulic cylinder 5FL~5R1? This is a low-pressure side accumulator that communicates with the hydraulic piping 27 between the two through a throttle valve 28V.

On the other hand, the vehicle body includes a lateral acceleration sensor 31 as an acceleration detection means for detecting lateral acceleration occurring in the vehicle body, and a longitudinal acceleration sensor 32 as an acceleration detection means for detecting longitudinal acceleration occurring in the vehicle body. The lateral acceleration detection values y of these lateral acceleration sensors 31 and the longitudinal acceleration detection values y of the longitudinal acceleration sensors 32 are supplied to the control device 30.

Further, 34 is a vehicle speed sensor as a vehicle speed detection means,
For example, the controller 30 is supplied with a vehicle speed detection signal DV, which is a pulse signal corresponding to the output rotation speed of a transmission (not shown).

The control device 30 has a microcomputer 35, as shown in FIG.
Interface circuit 36. It includes at least an arithmetic processing device 37 and a storage device 38, and the interface circuit 3
6, the interface circuit 36 includes a vehicle speed sensor 34.
The vehicle speed detection signal DV is directly supplied to the lateral acceleration sensor 3.
The detected lateral acceleration value 1 and the longitudinal acceleration detected value y of the longitudinal acceleration sensor 32 are supplied via A/D converters 40a and 40b.

The arithmetic processing unit 37 includes a vehicle speed sensor 34 . A steady state in which no acceleration is occurring in the vehicle is detected based on the detection signals DV, M, and y supplied from the lateral acceleration sensor 31 and the longitudinal acceleration sensor 32. The average value of each of the output values is set as the offset amount of the acceleration sensors 31 and 32 (that is, each acceleration detection value (and y correction value), and while taking this offset amount into consideration, both acceleration detection values parent and y
Each hydraulic cylinder 5FL to 5R1 has a force that suppresses changes in the posture of the vehicle body against the Each pressure control valve 71'L
The current value I of the command signal for 7RR is calculated and output from the interface circuit 36.

In this embodiment, the lateral acceleration that occurs when the vehicle turns to the left is the lateral acceleration in the positive direction, and the longitudinal acceleration that occurs when the vehicle is braked is the longitudinal acceleration in the positive direction. Therefore, for example, based on the positive lateral acceleration detection value detected when the vehicle turns left, the control device 30 determines whether the hydraulic cylinder 5Fl located on the right side of the vehicle body? Hydraulic cylinders 5F14 and 5RL located on the left side of the vehicle body increase the pressure in the pressure chambers of 5RR and 5RR.
A current value I of a command signal that lowers the pressure in the pressure chamber is calculated and supplied to each pressure control valve 7FL to 7RR.

Furthermore, the storage device 38 is composed of a ROM, a RAM, etc., and stores in advance programs, storage tables, etc. necessary for processing to be described later, and is configured to sequentially store calculation results of the arithmetic processing device 37. .

Furthermore, the control device 30 includes a D/A converter 41 . a~
41d and each command value I converted into an analog value is appropriately amplified and each pressure control valve 7F+, ~71? It has drive circuits 42a to 42d that supply power to R.

Next, the operation of the above embodiment will be explained.

6 and 7 are flowcharts showing the processing procedure executed within the microcomputer 35.
The figure shows that the current value ■ of the command signal for each pressure control valve 7FL to 7RR is calculated based on the acceleration detection values x and y of each acceleration sensor 31 and 32, and the correction value for these acceleration detection values x and y. It represents the processing procedure to output, and the seventh
The figure shows a processing procedure for detecting the steady state of the vehicle based on the vehicle speed detection value DV of the vehicle speed sensor 34 and the acceleration detection values y and y of each acceleration sensor 31 and 32, and calculating the correction value CX of the lateral acceleration detection value y. represents.

Note that the processing procedure for calculating the longitudinal acceleration detection (i-so correction (l-Cy) is basically the same as the processing in FIG. 7, so
Its illustration is omitted.

Furthermore, although the processes in FIGS. 6 and 7 are executed as timer interrupt processes at predetermined time intervals, the process in FIG. 7 (main program) has a higher interrupt interval than the process in FIG. For example, the main program should be set every 10m5ec, and the subprogram should be set every 1sec.
e).

First, the process shown in FIG. 6 will be explained.

That is, in step (2) in the figure, the lateral acceleration detection value z of the lateral acceleration sensor 31 and the longitudinal acceleration detection value y of the longitudinal acceleration sensor 32 are read and stored in a predetermined storage area of the storage device 38.

Next, the process proceeds to step (2), where each of the detected acceleration values and y stored in step (2) is filtered using a low-pass filter with a predetermined cutoff frequency, and the process proceeds to step (2), where the low-pass filter processing of this step (2) is performed. The difference values D and D7 (absolute values) between the input value of the filter (equal to the detected lateral acceleration value and the detected longitudinal acceleration value y stored in step 3) and the output value are calculated, and these are stored in the storage device 38. It is stored in a predetermined storage area. In addition, these difference values, and D
7 is a value necessary to obtain correction values C2 and Cy, which will be described later.

Next, the process moves to step (2), where a correction value CX for the detected lateral acceleration value and a correction value C for the detected longitudinal acceleration value y are determined.
Load 1. Note that the processing procedure for determining these corrections (direct C and C7 will be described later).

Then, proceed to step (2), and correct the lateral acceleration detection values and longitudinal acceleration detection (+!Y) stored in step (2) above based on the following formulas (1) and (2), The value χ and the longitudinal acceleration correction value Y are determined.

X = MCx・・・・・・
・(1) Y=S' CY ・・
(2) Next, the process moves to step (3), and based on the lateral acceleration correction value X and the longitudinal acceleration correction value Y, each pressure control valve 7FL to 7RI? Current value 1 (J
FL~1RR) is calculated.

That is, in this embodiment, since the positive direction of the lateral acceleration and longitudinal acceleration to be ordered to the vehicle body is set as described above, the command values IFL to IR for each pressure control valve 7FL to 7RR are
If the gain constant is KX and 7, then R is as follows (3
) to (6).

IFL=-KX X+KY Y ・・・・・・
(3) I FR-10Kx X + Kv Y
・・'-(4) IRL-KX X Ky Y
......(5) IRR-+Kx χ-, Y
(6) Then, proceed to step (2), and output the command values IFL to IRR calculated in step (2) from the interface circuit 36 to the D/A converter 4]
Each pressure control valve 7FL to 7RR is controlled via a to 41d and drive circuit 42a to 42d, and each hydraulic cylinder 5FL is
-Adjust the pressure in the pressure chamber of 5RR appropriately.

Then, a force is generated in each of the hydraulic cylinders 5FL to 5RR that resists the lateral acceleration and longitudinal acceleration generated in the vehicle body, so changes in the posture of the vehicle body due to these accelerations are suppressed, and good vehicle ride comfort is obtained.

It should be noted that aggressive measures should be taken against relatively low-frequency vibration input from the road surface via the wheels 3FL to 3RR and relatively high-frequency vibration input corresponding to the under-spring resonance frequency caused by minute irregularities on the road surface. Each hydraulic cylinder 5FI, ~51
Even if 'lIi is not controlled, the former is the pressure control valve 7FL.
~7RR is absorbed by the movement of the spool 14 due to pressure fluctuations in the foot bank chambers FL and Fu, the latter being absorbed by the throttle valve 28V and the accumulator 28[,].

Next, a description will be given of the seventh process, that is, the process of calculating the correction value CX for the detected lateral acceleration value.

The first half of the process shown in FIG. 7 is for detecting the steady state of the vehicle, and the second half is for calculating the correction value CX.

That is, in step (2), the vehicle speed detection signal DV supplied from the vehicle speed sensor 34 is read, and the vehicle speed (2) is calculated based on the pulse width of this vehicle speed detection signal DV.

Next, the process moves to step (2), and it is determined whether the vehicle speed (2) determined in the above step (2) is equal to or higher than a predetermined vehicle speed (4).

The predetermined vehicle speed ■ used in step ■ is a value determined based on preliminary experiments for each vehicle type, and is a threshold value for determining whether the steady state of the vehicle can be accurately detected in the following process. Vehicle speed ■ is less than the predetermined vehicle speed 74 (determination in step ■ is rN
OJ ), it is determined that a steady state cannot be detected (it may be a steady state, but it cannot be detected accurately), and moves to step [phase], where the counter CT, which will be described later,
and the integrated value X, are cleared to zero.

Here, the meaning of the process in step (2) will be explained in detail. In other words, when the vehicle speed ■ is high, a large lateral acceleration occurs even with a small turning. Therefore, in order to reliably detect a steady state, the lateral acceleration occurring at high speed is set to a predetermined acceleration (a threshold value described later). αI), the vehicle is traveling straight with a high probability (in other words, the detected lateral acceleration is detected (iM is the offset amount of the lateral acceleration sensor 31, and the possible pressure is high). You can judge.On the contrary,
When traveling at a constant speed, the gain of lateral acceleration relative to the steering angle (lateral G gain) is small, so even if the obtained lateral acceleration is minute, it cannot simply be determined that the vehicle is traveling straight. .

Therefore, the determination of step ■ is rYEsJ, that is, ■≧■
If , is true, a steady state can be detected, and
Move to step ■.

In step (2), based on the vehicle speed (2) determined in step (2) above, the
And with reference to the storage table as shown in (b), two threshold values α1 and α2 corresponding to the predetermined acceleration and the predetermined difference value in the invention according to claim (2) are determined.

As shown in FIGS. 8(a) and 8(b), these threshold values α1 and α2 basically tend to increase as the vehicle speed V increases (as mentioned above, as the vehicle speed However, exact characteristics such as the magnitude of inclination are determined based on preliminary experiments for each vehicle type.

Then, in step @, it is determined whether the detected lateral acceleration value stored in step (2) of the process in FIG. 6 is less than or equal to a threshold value α corresponding to a predetermined acceleration.

Here, if the vehicle is in a steady state (a state in which lateral acceleration is not occurring), the obtained lateral acceleration detected value is a component caused by the offset t of the lateral acceleration sensor 31 and a component caused by the vibration of the vehicle. It is the sum of the components.

Therefore, when the detected lateral acceleration value nu is larger than the threshold α determined based on the vehicle speed ■ (which has a large effect on vehicle vibration) (that is, when the determination in step @ is "NO"), the lateral Since the detected acceleration value includes not only the above two components but also a lateral acceleration component that occurs when the vehicle turns or runs in a bank, it is determined that the detected acceleration value is not in a steady state, and this process ends.

Therefore, the determination of step @ is rYEs, that is, father≦
If α1 is true, there is a high possibility that it is in a steady state.

Therefore, the process moves to step @, and it is determined whether the difference value Dx between the input value and the output value of the low-pass filter stored in step ① of the process in FIG. judge.

The determination in step (2) is for recognizing whether or not the detected lateral acceleration value contains a large amount of components caused by vibrations of the vehicle. Therefore, the cutoff frequency of the low-pass filter is set to a value that can attenuate vibration components (relatively high frequency) of the vehicle.

In other words, for example, when the vehicle is traveling on a rough road (therefore, it is not in a steady state), the detected lateral acceleration value contains a large amount of vibration components, and the difference value DX between the input value and output value of the low-pass filter becomes large. Therefore, the judgment of step @ is rNOJ
becomes. Therefore, when the detected lateral acceleration value g contains almost no vibration component, that is, when most of the detected lateral acceleration value is a component caused by the offset amount of the lateral acceleration sensor 31, the determination in step (3) is made as follows. It becomes rYEsJ.

Therefore, the determination in step (■) is rYEsJ, that is, D2
If ≦α2 is true, it can be determined that the vehicle is in a steady state.

That is, in this embodiment, when the determinations in step (2), step @, and step (2) are all true, it is determined that the vehicle is in a steady state.

Then, when the steady state of the vehicle is detected, the correction value CX is subsequently determined.

First, in step 0, the counter CT is incremented by one. This counter CT is a counter for determining whether a steady state has continued for a predetermined period of time.

Therefore, in the next step ■, after calculating the integrated value X+ (L = X+ Juji) of the detected lateral acceleration value, step [
If the counter CTI is equal to a predetermined value CT, it is determined whether or not the counter CTI is equal to a predetermined value CT.
<Limited to CTo) Judgment of step ■ is rYEsJ
,! : Repeat the above process until it becomes .

If the determination of phase [phase] is rYESJ, the process moves to step @, and the average value X'' (Xz=X+/CTo) of the detected lateral acceleration values in the steady state is calculated.

Next, the process moves to step [share], and it is determined whether the average value Xt obtained in step (2) is within a predetermined offset amount e that can be considered for a single acceleration sensor. That is, if the average value X2 is larger than the predetermined offset amount e, it is considered that not only the offset amount of the lateral acceleration sensor 31 but also a large amount of noise components in the circuit are included in the lateral acceleration detected value. , it is determined that it is inappropriate to set the correction value C9 based on such a value, and the process moves to the above step [phase], clears the counter CT and the integration (I X +), and executes this process. finish.

If the determination in step (■) is rYESJ, it can be determined that the average value X2 suitable for setting the correction value CX has been obtained, so proceed to step [phase] and set the counter CT2 to 1. Increment, and in step [phase], the integrated value X of the average value χ2.

Find (χ3=X3+Xz).

Then, in step 0, the integrated value X3 is divided by the counter CT2 to obtain an average value of the integrated value X3, and this is stored in a predetermined storage area of the storage device 38 as a correction value CX for the detected lateral acceleration value.

Finally, the process of step [phase] described in - is executed, and the current process of FIG. 7 is completed.

In this way, the process shown in FIG. 7 can detect the steady state of the vehicle without using an expensive steering angle sensor, so it can be implemented with an inexpensive configuration.

Note that the process for determining the correction value CY for the detected longitudinal acceleration value y is basically the same as the process shown in FIG. 7. That is,
The longitudinal acceleration detection value y may be used instead of the lateral acceleration detection value, and the difference value y may be used instead of the difference value DX. Furthermore, when lateral acceleration occurs in the vehicle, the longitudinal acceleration sensor 32 is also affected by it, so the determination of the steady state must be performed in the same manner as in FIG. 7 for longitudinal acceleration.

Furthermore, since the obtained correction values CX and Cy are the respective average values of the respective acceleration detection values y and y when the vehicle is determined to be in a steady state, the noise contained in each acceleration detection value y and y. (In the above embodiment, the average value is calculated twice, so the noise component is significantly reduced.), and the accurate offset amount of each acceleration sensor 31 and 32 is calculated as the correction value C8 and CV. can do.

Then, if accurate correction values C× and CY can be obtained, without using a highly accurate and expensive acceleration sensor (i.e.,
(with an inexpensive configuration), it is possible to perform good control of a controlled object, for example, active suspension control.

Here, the process of step (2) above constitutes a correction means, the process of step (2) and step (2) constitutes a control means, and the process of step (2), step (2), step (2), and step (2) constitute a control means.
, Step @, and Step [Phase] constitute steady state detection means, and Steps ① to 0 constitute correction value calculation means. In addition, among the steady state detection means,
Step ■ is applied to the J-th determining means, step @ is applied to the second determining means, step ■ is applied to the third determining means, and these steps ■
, step@, and step [phase] correspond to steady state determination means, respectively.

Next, a second embodiment of the present invention will be described.

9 and 10 show the main parts of the second embodiment of the present invention, 9M corresponds to FIG. 5 of the first embodiment, and FIG. 10 shows the main part of the second embodiment of the present invention. This is added to the example shown in FIG. 7.

That is, in this second embodiment, in order to detect the steady state of the vehicle more reliably, the conditions of the first embodiment (i.e., step ①, step @, and step ① in Fig. 7) are applied. In addition to the case where all judgments are rYESJ), it is now determined that the vehicle is in a steady state when the steering angle is at the neutral position, the throttle opening is constant, and the vehicle is not braking. It is something.

Therefore, to explain the configuration of this embodiment, as shown in FIG. 9, the microcomputer 35 has a steering wheel that detects the steering angle of the steering wheel (not shown) and outputs the steering angle detection signal Dθ. An angle sensor 50, a throttle sensor 51 that detects the opening degree of a throttle (not shown) and outputs an opening degree detection signal DS, and a logical value "1" when the brake (not shown) is not depressed. , and a brake switch 52 that outputs a brake detection signal DB whose logical value is "0" when the brake switch is depressed. Also,
Since the detection signals Dθ and DS of the steering angle sensor 50 and the throttle sensor 51 are analog values, A/D converters 40c and 40d are provided.

The microcomputer 35 then controls each sensor 50,
The processing described below is executed based on the detection signals Dθ, DS, and DB supplied from 51 and 52, and if it can be determined that the steady state is clearly not present, the process of FIG. 7 is not executed and the steady state is not detected. Therefore, the correction value calculation process is not performed.

That is, only when it is determined based on the detection signals Dθ, DS, and DB that the steering is in the neutral position and the vehicle is traveling at a constant speed without acceleration or deceleration, the process shown in FIG. 7 is executed. It determines the steady state and calculates the correction value.

Note that the other configurations are the same as those of the first embodiment, so illustration and description thereof will be omitted.

Next, the operation of this second embodiment will be explained.

FIG. 10 shows the processing unique to this embodiment among the processing executed by the microcomputer 35, and the sixth
The processes shown in the figures and FIG. 7 are also executed in the same manner as in the first embodiment.

That is, in step @, the steering angle detection signal Dθ of the steering angle sensor 50, the opening detection signal DS of the throttle sensor 51, and the brake detection signal DB of the brake switch 52 are read, and each is determined as a steering angle detection value θ.

It is stored as the throttle opening degree S and the brake signal B in a predetermined storage area of the storage device 38.

Next, the process moves to step O, and it is determined whether the brake signal B stored in step 0 has a logical value of "1". In other words, if the brake signal B is not a logical value of "1", the vehicle is braking (decelerating) and is clearly not in a steady state. Therefore, if the step [phase] is determined as rNOJ, the correction value is This process ends without calculation.

Then, the determination in step 0 is "YES", that is, B=r
If lJ is true, it is determined that deceleration by the brake is not being performed, and the process moves to step [phase].

In step @, it is determined whether the absolute value of the detected steering angle value θ is less than or equal to a value β that takes into account the play of the steering wheel. If the determination in this step [phase] is rNOJ, it can be determined that the vehicle is turning and is clearly not in a steady state, so this process is ended without calculating the correction value.

On the other hand, the process of step [phase] is rYEsJ, that is, θ
If 1≦β is true, it can be determined that the vehicle is traveling straight, so the process moves to step (2).

Then, in step (2), numerical differentiation is performed based on the throttle detection value S, and a differential value ΔS indicating the amount of change in the throttle detection value S is calculated.

Next, the process moves to step [phase], and it is determined whether the absolute value of the differential value ΔS obtained in step @ is less than or equal to a sufficiently small value T, that is, whether the throttle opening is held substantially constant. Determine whether

If the determination in this step [phase] is rNOJ, the vehicle is either accelerating or decelerating due to engine braking, so it is clearly not in a steady state, so this process ends without calculating the correction value. .

Then, the determination of step [phase] is rYESJ, that is, Δ
If S1≦T is true, it can be determined that the acceleration/deceleration is not in progress, so the process moves to step (2) in FIG. Calculate.

Note that the other functions are the same as those in the first embodiment described in Section 2.

In this way, according to the second embodiment, since it is possible to clearly detect that the steady state is not present, the steady state can be detected more reliably than in the first embodiment. Therefore, the calculation accuracy of the correction values C8 and Cv, that is, the control accuracy for the controlled object, for example, the active suspension, is further improved.

Here, the steering angle sensor 50 and the processing in step 0 constitute a neutral position detection means, the throttle sensor 51 and the processing in steps [phase] and step @ constitute a throttle opening detection means, and the brake switch 52 and the processing in step 0 constitute a throttle opening detection means. The braking detection means is constituted by the processing.

Note that an actual steering angle sensor that detects the actual steering angle of the steered wheels may be used in place of the steering angle sensor 50, and the throttle opening detection means is not limited to the throttle sensor 51, for example. Alternatively, the amount of fuel supplied to the engine may be detected, and it may be detected from the rate of change of the fuel that the throttle opening is held constant.

Further, in the first and second embodiments described above, the case where hydraulic pressure was used as the working fluid pressure was explained, but the present invention is not limited to this, and it is also possible to apply other fluid pressures such as air pressure. .

Furthermore, in the first and second embodiments described above, the case where the microcomputer 35 is used as the control device 30 has been described, but the invention is not limited to this, and instead of the microcomputer 35, a comparator or a function generator may be used. The control device 30 can also be configured using an electronic circuit such as the following.

In the above-described embodiment, the present invention is applied to an active suspension as a control target, but the control target may also be an anti-skid control device, a traction control device, etc. that use acceleration values for control,
The present invention can be applied to wheel steering devices and the like.

〔Effect of the invention〕

As explained above, according to the invention set forth in claim (1), the steady state of the vehicle is detected, and the average value of the acceleration detection values of the acceleration detection means at that time is used as a correction value, and the offset amount is calculated from the acceleration detection value. Since the configuration eliminates the offset, accurate correction values can be calculated and the offset amount can be reliably eliminated. This has the effect that it is possible to control the

Further, according to the invention described in claim (2), since the steady state of the vehicle is determined without using a steering angle sensor, in addition to the effect of the invention described in claim (1), This has the effect of reducing costs.

Furthermore, according to the invention set forth in claim (3), since the configuration is configured to detect cases where the steady state is clearly not achieved,
Since the steady state can be detected more reliably, there is an effect that the calculation accuracy of the correction value, that is, the control accuracy for the controlled object is further improved.

[Brief explanation of the drawing]

FIG. 1(a) is a block diagram showing the basic configuration of the invention as claimed in claim (1), FIG. 1(0)) is a block diagram showing the basic configuration of the invention as claimed in claim (2), FIG. C) is the claim (
3) is a block diagram showing the basic configuration of the invention; FIG. 2 is a block diagram showing the first embodiment of the invention; FIG. 3 is a sectional view showing an example of a pressure control valve applicable to the invention; The figure is a graph showing the relationship between the current value of the command signal and the output pressure of the pressure control valve in Fig. 3, Fig. 5 is a block diagram showing the configuration of the control device of this embodiment, and Figs. 6 and 7 are A flowchart showing the processing procedure executed in the microcomputer of this embodiment, FIGS. 8(a) and 8(b) are graphs showing an example of the relationship between vehicle speed and darkness value, and FIG. FIG. 10 is a block diagram showing the configuration of the control device of the second embodiment, and a flowchart showing the main part of the processing procedure executed within the microcomputer of the second embodiment. IFL~1. RR...Active suspension (control target), 2...Vehicle side member, 3FL~3RR...Wheel, 5FL~51? R...Hydraulic cylinder, 7FL~7R
R...Pressure control valve, 30...Control device, 31...
Lateral acceleration sensor, 32... Longitudinal acceleration sensor (these 31 and 32 are acceleration detection means), 34... Vehicle speed sensor (vehicle speed detection means), 35... Microcomputer, 50... Rudder angle sensor (neutral) position detection means), 51.
...Throntl sensor (throttle opening detection means), 5
2... Brake switch (braking detection means).

Claims (3)

[Claims] (1) An acceleration detection means for detecting acceleration generated in the vehicle body, a steady state detection means for detecting a steady state in which the acceleration is not generated in the vehicle, and this steady state detection means detects that the vehicle is in a steady state. correction value calculation means for calculating an average value of the acceleration detection values of the acceleration detection means at the time as a correction value; and correction means for correcting the acceleration detection value of the acceleration detection means with the correction value calculated by the correction value calculation means. ,
A correction device for a detected acceleration value of a vehicle, comprising: control means for outputting a command signal to a controlled object appropriately provided in the vehicle in accordance with the detected acceleration value corrected by the correction means. (2) A vehicle speed detection means for detecting vehicle speed is provided, and the steady state detection means includes a first determination means for determining whether or not a vehicle speed detection value of the vehicle speed detection means is equal to or higher than a predetermined vehicle speed; a second determining means for determining whether or not the detected acceleration value of the means is equal to or less than a predetermined acceleration; a low-pass filter to which the detected acceleration value of the acceleration detecting means is input; and an input value and an output value of the low-pass filter. a third determining means for determining whether the difference value is less than or equal to a predetermined difference value; and determining that the vehicle is in a steady state when all of the determination results of the first, second, and third determining means are true. A correction device for a detected acceleration value of a vehicle according to claim 1, further comprising steady state determining means. (3) Neutral position detection means for detecting that the steering angle is at the neutral position, throttle opening detection means for detecting that the throttle opening is held constant, and braking detection means for detecting that the vehicle is not braking. At least one of the detection means is provided, and when the detection result of the provided detection means is true and the determination results of the first, second and third determination means are all true, the 3. A correction device for a detected acceleration value of a vehicle according to claim 2, wherein the steady state determining means of the steady state detecting means determines that the vehicle is in a steady state.