JP2887997B2 - Abnormality detection device for lateral acceleration sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lateral acceleration sensor abnormality detecting device used as a sensor for providing control information in a vehicle-mounted traction control system, suspension control system, 4WS control system, torque split control system, or the like. .

[0002]

2. Description of the Related Art Conventionally, as an abnormality detecting device of an acceleration sensor, for example, devices described in Japanese Patent Application Laid-Open Nos. 1-103507 and 1-1115717 are known.

[0003] The former publication discloses a vehicle suspension control system in which a vehicle suspension control is performed when an acceleration equal to or higher than a preset acceleration is continuously detected from an acceleration sensor for a predetermined time or more, or based on the acceleration detected by the acceleration sensor. A technique is shown in which the acceleration sensor determines that the acceleration sensor is abnormal when is continuously detected for a predetermined time or more.

[0004] In the latter publication, in an active suspension device, a vertical acceleration detection value is sliced at a slice level, and the slice level is appropriately changed according to a vehicle speed. A technique is disclosed in which bounce control is performed by calculating a speed to perform fail-safe in the event of a failure of the vertical acceleration detecting means.

[0005]

However, in the former device, since a time element is included in the abnormality determination, at least a predetermined time does not elapse after the acceleration sensor abnormality occurs. In particular, it is not possible to detect abnormality of the acceleration sensor. As a result, from the occurrence of the sensor abnormality to the detection of the sensor abnormality, the vehicle body roll control is performed based on the abnormal acceleration sensor signal.

The latter device is a fail-safe technique which suppresses the influence on the bounce control using the acceleration information as control information even if the acceleration sensor becomes abnormal, and detects the abnormality of the acceleration sensor itself. Can not.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problem. In a lateral acceleration sensor abnormality detecting device mounted as control information output means of an on-vehicle control system, a response is made when a lateral acceleration sensor abnormality occurs. It is an object to detect a sensor abnormality well and accurately.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an abnormality detecting device for a lateral acceleration sensor according to the present invention is divided into a normal region and an abnormal region according to the relationship between the vehicle speed and the lateral acceleration.
Means for detecting an abnormality of the lateral acceleration sensor using a lateral acceleration abnormality determination map having two-dimensional boundary characteristics .

That is, as shown in the claim correspondence diagram of FIG. 1, a lateral acceleration sensor a for detecting a lateral acceleration, a vehicle speed detecting means b for detecting a vehicle speed, and if the magnitude relationship between the vehicle speed and the lateral acceleration is normal. A lateral load that may occur with an increase in vehicle speed is set such that a possible region is regarded as a normal region, and a region where the vehicle speed and the lateral acceleration have a normal magnitude relationship is regarded as an abnormal region if the magnitude relationship is not normal.
A lateral acceleration abnormality determination map c having boundary characteristics determined to increase the speed; and a lateral acceleration sensor when a point specified by the lateral acceleration sensor value and the vehicle speed detection value exists in an abnormal region of the lateral acceleration abnormality determination map c. and a lateral acceleration sensor abnormality detecting means d for detecting that a is abnormal.

Here, the lateral acceleration sensor a includes not only the lateral acceleration sensor itself but also a lateral acceleration input circuit for converting a sensor signal into control information.

The lateral acceleration abnormality determination map is, for example, a map that determines that the vehicle is normal when the vehicle speed is equal to or less than a predetermined lateral acceleration at a vehicle speed of zero.

[0012]

First, if the magnitude relation between the vehicle speed and the lateral acceleration is normal, a possible area is defined as a normal area, and if the magnitude relation between the vehicle speed and the lateral acceleration is normal, an impossible area is defined as an abnormal area .
The lateral acceleration that can occur with increasing vehicle speed
A lateral acceleration abnormality determination map c having a boundary characteristic determined so as to be prepared is prepared in advance.

The abnormality of the lateral acceleration sensor a is determined by the lateral acceleration sensor abnormality detecting means d based on the lateral acceleration sensor value from the lateral acceleration sensor a for detecting the lateral acceleration and the vehicle speed detection value from the vehicle speed detecting means b for detecting the vehicle speed. When the specified point exists in the abnormal area of the lateral acceleration abnormality determination map c, it is detected that the lateral acceleration sensor a is abnormal.

As described above, since the time component is not included in the detection of the abnormality of the lateral acceleration sensor a, it is possible to immediately detect that the lateral acceleration sensor a is abnormal when the sensor abnormality occurs, The area division of the determination map c is determined by the boundary characteristics determined based on the relationship between the vehicle speed and the lateral acceleration.
By setting with high accuracy, it is possible to reliably detect not only an abnormality due to a short circuit or the like but also an abnormality such that the sensor value is offset from the normal value by a predetermined amount.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration will be described.

FIG. 2 is an overall diagram of a braking / driving system control system for a rear wheel drive vehicle to which the abnormality detection device for a lateral acceleration sensor according to the embodiment of the present invention is applied.

This rear wheel drive vehicle has a throttle control for controlling a motor throttle opening degree so that a rear wheel slip ratio is within an optimum allowable range when an acceleration slip occurs, and is independent for right and left rear wheels when an acceleration slip occurs. In addition to a traction control system that is used in combination with a brake control that applies a braking force, an anti-skid brake control system that performs front and rear wheel brake fluid pressure control to prevent wheel lock during deceleration slip is mounted. Centralized electronic control of these systems is performed by a traction control system & anti-skid brake control system electronic control unit TCS / ABS-ECU (hereinafter abbreviated as TCS / ABS-ECU).

The TCS / ABS-ECU has a right front wheel speed sensor 1
From the right front wheel speed sensor value VWFR, the left front wheel speed sensor value VWFL from the left front wheel speed sensor 2, the right rear wheel speed sensor value VWRR from the right rear wheel speed sensor 3, and the Left rear wheel speed sensor value VWRL, lateral acceleration sensor value YG from lateral acceleration sensor 5, switch signal SWTC from TCS switch 6, switch signal SWST from brake lamp switch 7, throttle control module TCM (hereinafter, referred to as Throttle 1 actual opening DKV from TCM)
And the automatic transmission control unit A /
Gear position signal and shift-up signal from TC / U (hereinafter abbreviated as A / TC / U) and engine rotation from ECCS C / U (hereinafter abbreviated as ECCS C / U) A number signal, a second throttle signal TVO2 from the second throttle sensor 17, and the like are input.

From the TCS / ABS-ECU, an acceleration slip is detected and the throttle 2 as a throttle opening / closing signal is detected.
The target opening DKR is output to the TCM, and a solenoid signal as a brake pressure increase / decrease signal is output to each solenoid valve of the common hydraulic unit TCS / ABS-HU (hereinafter abbreviated as TCS / ABS-HU). . Of the traction control, the throttle control side is called TCS throttle control, and the brake control side is called TCS brake control.

The TCS / ABS-ECU detects a deceleration slip and outputs a solenoid signal as a brake pressure increasing / decreasing signal to each solenoid valve of the TCS / ABS-HU. This anti-skid brake control is called ABS brake control.

In addition to the above output, the TCS / ABS-ECU outputs a lighting command to the TCS fail lamp 14 when the TCS fails, and outputs a lighting command to the TCS operating lamp 15 during the TCS operation.

The TCM is a control circuit mainly including a throttle motor drive circuit. The TCM receives a first throttle signal TVO1 from a first throttle sensor 16 and outputs the same to a TCS / ABS-ECU as a throttle 1 actual opening degree DKV. Or input the second throttle signal TVO2 from the second throttle sensor 17 as feedback information to the throttle 2 target opening DKR, or input the throttle 2 target opening DK from the TCS / ABS-ECU.
A motor drive current IM is applied to the throttle motor 18 based on R.

Here, the first throttle valve 19 provided with the first throttle sensor 16 is connected to the accelerator pedal 2.
The second throttle valve 21 provided with the second throttle sensor 17 is provided in the engine intake passage 22 in series with the first throttle valve 19, and is opened / closed by the throttle motor 18. Valve.

The traction control system includes an air flow meter AFM as a peripheral system as shown in FIG.
And an ECCS C / U and an injector, and an engine centralized electronic control system that performs centralized control of fuel injection control, ignition timing control, idle speed correction, etc., is installed. When the ON signal is input, control (select low control) for selecting a smaller valve opening degree of the first throttle signal TVO1 and the second throttle signal TVO2 is performed for transient characteristic correction, and the canister control and the EGR control are performed. Aborted.

Further, as shown in the figure, an automatic transmission control system having an A / TC / U and a shift solenoid and performing a shift control and a lock-up control is mounted as a peripheral system as shown in FIG. , The gear position signal and the shift-up signal are taken into the TCS / ABS-ECU.

Further, as a peripheral system, as shown, a constant speed traveling control system having an ASCD actuator and performing automatic vehicle speed control so as to maintain a set vehicle speed is mounted. When the ON signal of the traction switch signal TCS SW is input, the opening control of the first throttle valve 19 is stopped, and when the OFF signal of the TCS SW is input, the return speed of the first throttle valve 19 is reduced.

FIG. 3 is a hydraulic circuit diagram showing a brake fluid pressure control system commonly used for TCS brake control and ABS brake control for the left and right rear wheels independently.

This brake fluid pressure control system comprises a brake pedal 27, a hydraulic booster 28, a master cylinder 30 having a reservoir 29, wheel cylinders 31, 32,
33, 34, shared hydraulic unit TCS / ABS-HU
, Pump unit PU, and first accumulator unit
AU1, second accumulator unit AU2, front wheel side damping unit FDPU, rear wheel side damping unit RD
With PU.

The TCS / ABS-HU has a first switching valve 35a.
, A second switching valve 35b, and a left front wheel pressure increasing valve 36a.
, A right front wheel pressure increasing valve 36b and a left rear wheel pressure increasing valve 36
c, right rear wheel pressure increasing valve 36d, left front wheel pressure reducing valve 3
7a, a right front wheel pressure reducing valve 37b, a left rear wheel pressure reducing valve 37c, a right rear wheel pressure reducing valve 37c, a front wheel side reservoir 38a, a rear wheel side reservoir 38b, and a front wheel side pump 39.
a, a rear wheel side pump 39b, and a front wheel side damper chamber 40a.
And a rear-wheel-side damper chamber 40b and a pump motor 41.

At the time of normal braking or ABS brake control, both switching valves 35a and 35b are turned off as shown in the figure to introduce the hydraulic pressure from the master cylinder 30.
During the TCS brake control, both switching valves 35a and 35b are turned on to introduce the hydraulic pressure from the second accumulator unit AU2. For example, in the pressure increase mode in the TCS brake control, both control valves 36c, 36d, 37c, and 37d are connected as shown in the figure.
It is set to the OFF position.
In the pressure reduction mode, both control valves 36c, 36d, 37c, 37d are set to the ON position, and the brake fluid from the wheel cylinders 33, 34 is stored in the rear wheel side reservoir 38b. The rotation of the rear wheel side pump 39b returns to the rear wheel side damper chamber 40b.

The first accumulator unit AU1 is used as a hydraulic pressure source for the hydraulic booster 28, and the second accumulator unit AU2 is used as a hydraulic pressure source for TCS brake control. A predetermined accumulator pressure is maintained by the common pump unit PU that sucks in.

The front-wheel-side damping unit FDPU and the rear-wheel-side damping unit RDPU are provided with a common hydraulic unit TCS / AB in order to improve pedal feeling.
The influence of the fluid pressure change in the S-HU on the master cylinder 30 is suppressed.

The operation will be described.

(A) Normal Traction Control Operation FIG. 4 is a control block diagram showing the outline of the traction control performed by the TCS / ABS-ECU. The traction control logic can be roughly classified into the following four types of control.

(1) Calculation of actual slip state Filter processing is performed on the signals of the wheel speed sensors 1, 2, 3, and 4, and based on the wheel speed values after the filter processing, the actual slip state (slip amount, slip amount difference value) is calculated. ) Is calculated.

(2) Calculation of Target Slip State Filter processing is performed on the signal of the lateral acceleration sensor 5 to calculate a target slip state appropriate for the traveling state based on the determination of turning / straight running based on the lateral acceleration YG and the vehicle speed.

(3) TCS Brake Control The required slip increase / decrease speed (control duty ratio) is calculated by comparing the actual slip state with the target slip state, and is output to the TCS / ABS-HU.

(4) TCS Throttle Control The necessary throttle opening and opening / closing speed are calculated by comparing the actual slip state with the target slip state and output to the TCM.

The characteristics of this control logic are as follows:
In order to secure the limit detectability (steering force, skill sound, etc.) based on the base chassis performance and obtain active safety according to each road surface condition leading to the allowable slip state according to the magnitude of the lateral acceleration YG , The division of throttle / brake control is decided.

Further, in order to secure stability during shifting and to improve controllability at each gear position, throttle / brake control according to the gear position is performed.

Further, in order to realize smooth acceleration feeling and controllability while suppressing slip hunting, and to realize a responsive engine torque increase / decrease control, an optimum throttle control according to the engine speed is performed.

FIG. 5 is a flowchart showing the flow of the lateral acceleration sensor abnormality detection processing operation using the optimum gain performed by the TCS / ABS-ECU in the TCS / ABS-ECU. (Corresponds to sensor abnormality detection means).

In step 50, the lateral acceleration sensor value YG _SEN is applied to a preset lateral acceleration abnormality determination map M.
It is determined whether the point specified by the vehicle speed detection value VFTF exists in the OK region or the NG region.

The lateral acceleration abnormality determination map M indicates the vehicle speed V
In the map, a region where the magnitude relationship between the lateral acceleration YG and the vehicle acceleration VG is normal is an OK region, and a region where the magnitude relationship between the vehicle speed V and the lateral acceleration YG is normal is an NG region. The boundary characteristic F (V) for dividing the area is given by the following equation.

F (V) = V ² / R _MIN + YGO R _MIN ; Minimum turning radius of the vehicle YGO; Considering (sensor unit error + mounting error + lateral acceleration input circuit error + vehicle attitude) of the lateral acceleration sensor 5 An error constant determined in this way, for example, is given as a value such as 0.15G.

The detected vehicle speed value VFTF is obtained by calculating an average value of the right front wheel speed sensor value VWFR and the left front wheel speed sensor value VWFL (corresponding to a vehicle speed detecting means).

In step 51, it is determined whether or not the result of the area determination in step 50 is the NG area of the lateral acceleration sensor.

When NO is determined in the step 51, the process proceeds to a step 52, where the acceleration slip control according to the lateral acceleration state, that is, the normal traction control operation described in the above (a) is performed.

When YES is determined in the step 51,
Based on the determination that the lateral acceleration sensor is abnormal, the acceleration slip control according to the lateral acceleration state is stopped.

Therefore, when the lateral acceleration sensor is normal, the flow proceeds to step 50 → step 51 → step 52, and the allowable slip state and the share of the throttle / brake control are determined according to the magnitude of the lateral acceleration YG. Acceleration slip control corresponding to lateral acceleration is performed to ensure safety while ensuring limit detectability (steering force, skill sound, etc.) based on base chassis performance according to each road surface condition leading to a high μ.

When the lateral acceleration sensor is abnormal, the flow proceeds from step 50 to step 51 to step 53. Since the normal operation of the acceleration slip control corresponding to the lateral acceleration is not secured, the operation is immediately stopped. In this case, it is decisive how to detect the lateral acceleration sensor abnormality with good response and accuracy from the occurrence of the abnormality.

On the other hand, a lateral acceleration abnormality determination map M divided into an OK region as a normal region and an NG region as an abnormal region is prepared in advance according to the magnitude relationship between the vehicle speed and the lateral acceleration. When the point specified by the acceleration sensor value YG _SEN and the vehicle speed detection value VFTF exists in the NG range, the abnormality of the lateral acceleration sensor 5 is detected.

As described above, since the time component is not included in the detection of the abnormality of the lateral acceleration sensor 5, it is possible to immediately detect that the lateral acceleration sensor 5 is abnormal when the sensor abnormality occurs, By setting the area division of the determination map M with high accuracy in consideration of various errors and the like,
It is possible to reliably detect not only an abnormality due to a short circuit or the like, but also an abnormality in which the sensor value is offset from the normal value by a predetermined amount.

The effect will be described.

(1) An apparatus for detecting an abnormality of the lateral acceleration sensor 5 using the lateral acceleration abnormality determination map M divided into an OK area and an NG area according to the magnitude relationship between the vehicle speed V and the lateral acceleration YG. If an abnormality of the acceleration sensor 5 occurs, the sensor abnormality can be detected with good response and high accuracy.

(2) Since the lateral acceleration sensor abnormality detecting device is applied to a traction control system using lateral acceleration information as control information, for example, the lateral acceleration sensor 5 is attached at an angle, is broken, and In the case of a failure of the lateral acceleration input circuit, etc., it is possible to prevent the acceleration slip control from being performed by erroneous lateral acceleration information at an early stage.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to this embodiment.

In the embodiment, the example in which the abnormality detecting device of the lateral acceleration sensor is applied to the traction control system is shown. However, various systems mounted on the vehicle using the lateral acceleration as control information, such as a suspension control system, a 4WS control system, a torque control system, and the like. A split control system or the like may be applied.

As the vehicle speed detecting means, a vehicle speed sensor detected by rotation of a transmission output shaft or the like may be used, or more accurate information may be selected from a plurality of vehicle speed information obtained by a wheel speed sensor and a vehicle speed sensor. Is also good.

[0060]

As described above, according to the present invention, in the abnormality detecting device of the lateral acceleration sensor mounted as the control information output means of the on-vehicle control system, the normal region is determined by the relationship between the vehicle speed and the lateral acceleration. Since the lateral acceleration sensor abnormality is detected using the lateral acceleration abnormality judgment map divided into abnormal regions, the sensor abnormality can be detected with good response and accuracy if the lateral acceleration sensor abnormality occurs. Is obtained. In addition, increasing vehicle speed
The boundary is set so that the lateral acceleration that can occur with
Area classification by lateral acceleration abnormality judgment map with field characteristics
Is set with high accuracy, so abnormal fools due to shorts etc.
The sensor value is offset by a predetermined amount from the normal value
Such an abnormality can be reliably detected.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to a claim showing an abnormality detection device for a lateral acceleration sensor according to the present invention.

FIG. 2 is an overall diagram of a braking / drive system control system for a rear wheel drive vehicle to which the abnormality detection device for a lateral acceleration sensor according to the embodiment is applied.

FIG. 3 is a hydraulic circuit diagram showing a brake fluid pressure control system of the braking / drive system control system to which the abnormality detection device for the lateral acceleration sensor of the embodiment is applied.

FIG. 4 is a block diagram illustrating an outline of traction control in the embodiment.

FIG. 5 is a flowchart showing a flow of a lateral acceleration sensor abnormality detection processing operation performed by a TCS & ABS electronic control unit of the embodiment device.

[Explanation of symbols]

 a lateral acceleration sensor b vehicle speed detecting means c lateral acceleration abnormality determination map d lateral acceleration sensor abnormality detecting means

Claims (2)

(57) [Claims] 1. A lateral acceleration sensor for detecting a lateral acceleration, a vehicle speed detecting means for detecting a vehicle speed, a region where the magnitude relationship between the vehicle speed and the lateral acceleration is normal is defined as a normal region, The vehicle speed is set so that an area that is impossible if the size relationship is normal is regarded as an abnormal area.
To increase the lateral acceleration that can occur as the
A lateral acceleration abnormality determination map having boundary characteristics, and a lateral acceleration sensor that detects an abnormality when the point specified by the lateral acceleration sensor value and the vehicle speed detection value exists in an abnormal region of the lateral acceleration abnormality determination map. An abnormality detection device for a lateral acceleration sensor, comprising: acceleration sensor abnormality detection means. 2. The lateral acceleration abnormality determination map according to claim 1, wherein the vehicle speed is zero.
2. The abnormality detection device for a lateral acceleration sensor according to claim 1, wherein the map is determined to be normal when the magnitude of the lateral acceleration is equal to or smaller than a predetermined value.