JP3099576B2 - Detection yaw rate correction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detected yaw rate correction device applied to a four-wheel steering device for providing an auxiliary steering angle by yaw rate feedback control during front wheel steering.

[0002]

2. Description of the Related Art Conventionally, as a detected yaw rate correction device applied to a four-wheel steering device for giving an auxiliary steering angle to a rear wheel by yaw rate feedback control during front wheel steering, for example, Japanese Patent Application Laid-Open No. 62-261575 discloses Devices are known.

According to this conventional source, when a vehicle stop state is detected, a value corresponding to a deviation of a sampled detected yaw rate from a reference value is accumulated, and the reference value is updated based on the accumulation result. Accordingly, a technique for correcting a zero point shift of a detected yaw rate (output value of a yaw rate sensor) has been disclosed.

[0004]

However, in the above-mentioned conventional detected yaw rate correction apparatus, since the zero point correction of the output value of the yaw rate sensor is performed when the vehicle stopped state is detected, the apparatus is not used for a long time. Although it is possible to cope with the time-dependent change of the yaw rate sensor in which the zero point offset gradually occurs due to
If the vehicle rolls or pitches, this low
If the output value of the yaw rate sensor changes due to the influence of the occurrence of the yaw rate or the pitch , it is impossible to cope with the change.For example, there is an error in the rear wheel steering angle control by the yaw rate feedback that matches the actual yaw rate value to the target yaw rate value. When the actual yaw rate value is used as the control information, the control is directly affected, the control accuracy is reduced, and the turning performance of the vehicle is deteriorated.

That is, as shown in FIG. 10, a yaw rate sensor having a triangular gyro structure is installed in a direction perpendicular to a vehicle plane to suppress cone-shaped movement, and detects yaw applied to the vehicle around the z-axis. Therefore, when a roll about the x-axis or a pitch about the y-axis occurs, the z-axis is inclined, and the detected yaw value changes.

[0006] For example, in the no-load of the yaw rate is zero, looking at the yaw rate sensor output value characteristic of the yaw rate sensor when fed a roll angle and a pitch angle, respectively, as shown in FIG. 11, the yaw rate at the time of the roll angle added The sensor output value changes as shown by the one-dot chain line characteristic,
When a pitch angle is added, the output value of the yaw rate sensor changes as shown by the two-dot chain line characteristic, and when a roll or a pitch is added, it is erroneously detected that a yaw rate has occurred.

Therefore, when the roll and the pitch occur simultaneously with the occurrence of the yaw rate during the actual turning, the output value of the yaw rate sensor becomes a value offset from the true value.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. It is an object of the present invention to provide a yaw rate correction device for detecting a yaw rate sensor provided in a vehicle. An object of the present invention is to improve the reliability of the actual yaw rate value by removing the influence of the roll and pitch during running of the vehicle.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a detection yaw rate correction apparatus according to the present invention uses a vertical direction with respect to a vehicle plane inclined based on a roll equivalent value and a pitch equivalent value.
The output value of the yaw rate sensor around the axis
Actual yaw rate value calculating means for determining a roll correction coefficient and a pitch correction coefficient to be corrected to values around the vertical axis to be calculated, and calculating an actual yaw rate value from the roll correction coefficient and the pitch correction coefficient and a yaw rate sensor output value from the yaw rate sensor. Was.

That is, as shown in the claim correspondence diagram of FIG. 1, a yaw rate sensor a which is installed in a direction perpendicular to the vehicle plane and detects a yaw rate applied to the vehicle, and a roll equivalent value which detects a roll equivalent value applied to the vehicle Detection means b
When a pitch corresponding value detecting means c for detecting a pitch corresponding value applied to the vehicle, the vehicle row by the detected roll equivalent value
The roll angle is estimated, and based on this vehicle roll angle , the roll inclination
Yaw rate sensor about an axis perpendicular to the
The output value to a value about a vertical axis orthogonal to the road surface.
And a roll correction coefficient setting means d for determining a roll correction coefficient for determining the vehicle pitch angle based on the detected pitch equivalent value.
Estimated, based on the vehicle pitch angle and the pitch inclined car
Yaw rate sensor output about an axis perpendicular to both planes
To correct the value to a value about a vertical axis perpendicular to the road surface
Pitch correction coefficient setting means e which determines the pitch correction coefficient
And an actual yaw rate value calculating means f for calculating an actual yaw rate value from the yaw rate sensor output value, the roll correction coefficient and the pitch correction coefficient.

[0011]

When the vehicle is running, the yaw rate sensor a installed in the direction perpendicular to the plane of the vehicle detects the yaw rate applied to the vehicle.

On the other hand, the roll correction coefficient setting means d estimates the roll angle of the vehicle based on the detected roll equivalent value.
It is, on the basis of the vehicle roll angle, roll inclined vehicle
Output value of the yaw rate sensor about an axis perpendicular to the plane
Roll correction coefficient is determined for correcting the rotation angle to a value about a vertical axis orthogonal to the road surface, and pitch correction coefficient setting means e
At the vehicle pitch angle according to the detected pitch equivalent value
Is estimated, and based on this vehicle pitch angle , the pitch
Sensor around an axis perpendicular to the closed vehicle plane
Correct the output value to a value around a vertical axis perpendicular to the road surface
Pitch correction coefficients for is determined.

Then, the actual yaw rate value calculating means f calculates the actual yaw rate value from the yaw rate sensor output value from the yaw rate sensor a, the roll correction coefficient and the pitch correction coefficient.

Therefore, when turning such that a yaw rate occurs, and simultaneously when a roll or a pitch occurs,
A roll correction coefficient and a pitch correction coefficient for correcting to a value around a vertical axis orthogonal to the traveling road surface are determined, and the yaw rate sensor output value from the yaw rate sensor a is corrected using the correction coefficient, Since the actual yaw rate value is calculated, the effect of the roll and the pitch are removed from the actual yaw rate value, and the reliability of the actual yaw rate value is improved.

As a result, for example, when the actual yaw rate value is used for the yaw rate feedback control, highly accurate control can be performed.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

The configuration will be described.

FIG. 2 is an overall system diagram showing a four-wheel steering vehicle to which the detected yaw rate correction device according to the embodiment of the present invention is applied.

In FIG. 2, the front wheels 1 and 2 are steered by a steering handle 3 and a mechanical link type steering mechanism 4.
Done by This includes, for example, a steering gear, a pitman arm, a relay rod, side rods 5, 6, knuckle arms 7, 8, and the like.

The steering of the rear wheels 9, 10 is performed by an electric steering device 11. This rear wheel 9,
Between 10, the rack shaft 12, the side rods 13, 1
4. The rack tube 17 in which the rack 12 is inserted and connected by the knuckle arms 15 and 16 has a speed reduction mechanism 1
8, a motor 19 and a fail-safe solenoid 20 are provided.
Are a vehicle speed sensor 21, a front wheel steering angle sensor 22, a rear steering angle sub-sensor 23, a rear steering angle main sensor 24, a yaw rate sensor 25 (corresponding to a yaw rate sensor a), a temperature sensor 27, and a lateral acceleration sensor 28 ( roll equivalent value detecting means). b), and a controller 26 that inputs signals from a longitudinal acceleration sensor 29 (corresponding to pitch equivalent value detecting means c) and the like.

FIG. 3 is a sectional view showing a specific structure of the electric steering apparatus 11.

In FIG. 3, a rack tube 17 in which a rack 12 is inserted is fixed to a vehicle body via a bracket. Side rods 13 and 14 are connected to both ends of the rack 12 via ball joints 30 and 31. The reduction mechanism 18 includes a motor pinion 32 connected to the motor shaft of the motor 19, a ring gear 33 meshing with the motor pinion 32, and a rack pinion 35 fixed to the ring gear 33 and meshing with the rack gear 12a. Have been. Therefore, when the motor shaft of the motor 19 rotates, the rotation is transmitted to the motor pinion 32 → the ring gear 33 → the rack pinion 35, and the rack shaft 12 moves in the axial direction due to the engagement between the rotating rack pinion 35 and the rack gear 12a. The rear wheels 9, 10 are steered. This rear wheel 9,10
Is proportional to the amount of movement of the rack shaft 12, that is, the amount of rotation of the motor shaft.

The rack pinion 35 is provided with a rear steering angle main sensor 24 having a potentiometer structure for detecting the rear wheel steering angle based on the rotation amount.

The fail-safe solenoid 20 includes:
The lock pin 20a is provided so as to be able to advance and retreat, and when the electronic control system or the like fails, the lock shaft 20a is fitted into a lock groove 12b formed in the rack shaft 12 so that the rack shaft 12 and the rear wheels 9, 10 can be moved. It is fixed at a position to maintain the neutral steering angle position.

The operation will be described.

[Rear Wheel Steering Angle Control Operation] FIG. 4 is a flowchart showing the flow of the rear wheel steering angle control operation performed by the controller 26. Each step will be described below.

In step 40, the vehicle speed V, the steering angle θ, the actual yaw rate value ψ'O, and the rear steering angle main sensor value δrS are read.

Here, the actual yaw rate value ψ'O is calculated by a detected yaw rate correction process shown in FIG. 5 to be described later, and is updated to the latest value stored in the memory.

In step 41, a target yaw rate steady value ψ'MO as a yaw rate value per unit steering angle is calculated for each vehicle speed based on the vehicle speed V and the steering angle θ.

In step 42, it is determined whether or not a value obtained by multiplying the steering angle θ by the steering angle differential value θ ′ is 0 or more.

That is, when θ · θ ′ ≧ 0, it is determined that the steering angle change direction is the turning-up direction, and when θ · θ ′ <0, the steering angle change direction is turned back. The direction is determined.

In step 43, θ · θ ′ ≧ 0, and
When it is determined that the steering angle change direction is the turning direction, the first-order lag time constant TO is set to a low value TOp (<TOm) for obtaining the turning property.

In step 44, θ · θ ′ <0, and
When it is determined that the steering steering angle change direction is the return direction, the first-order lag time constant TO is set to TOm (> TOp) with a high value for obtaining convergence.

In step 45, the target yaw rate ψ'M is calculated by the following equation using the target yaw rate steady-state value ψ'MO and the first-order lag time constant TO set in step 43 or step 44.

Ψ'M = ψ'MO / (1 + TO · S) S;
In the Laplace operator step 46, a deviation ε between the target yaw rate ψ′M and the actual yaw rate value ψ′O is calculated.

In step 47, the deviation ε is determined according to the vehicle speed V.
Are set on the basis of the map.

In step 48, the deviation ε and the proportional term K
The feedback rear wheel steering angle δrF / B is calculated by the following equation based on P and the differential term KD.

At step 49, the feedback rear wheel steering angle δrF / B at step 48 is converted to a motor rotation target value THi.

In step 50, the rear steering angle main sensor value δrS is converted to an actual motor rotation value THNO.

In step 51, the motor control current IM is calculated from the motor rotation target value THi and the motor rotation actual value THNO.

In step 52, PW is set according to the output command.
The duty ratio of M is controlled, and a motor control current IM is output.

[Detected Yaw Rate Correction Processing] FIG. 5 is a flowchart showing the flow of the detected yaw rate correction processing operation performed by the controller 26. Each step will be described below.

In step 60, the temperature T from the temperature sensor 27 and the yaw rate sensor output value Vψ 'from the yaw rate sensor 25 are read.

In step 61, a temperature drift correction coefficient K1 is calculated based on the temperature T.

The temperature drift correction coefficient K1 is obtained by measuring the change in the zero point while changing the temperature in the state where the yaw rate is not loaded, and based on the measurement result, as shown in FIG.
The coefficient is set as a coefficient for performing zero point correction eliminating the influence of temperature drift.

In step 62, a gain correction coefficient K2 is calculated based on the yaw rate sensor output value Vψ '.

Since the output from the yaw rate sensor 25 fluctuates as the occurrence of the yaw rate increases, the gain correction coefficient K2 is corrected as shown in FIG.
It is set as a yaw rate sensitivity coefficient corresponding to the yaw rate sensor output value Vψ '.

In step 63, the temperature drift correction coefficient K1, the gain correction coefficient K2, the yaw rate sensor output value V
The temperature correction yaw rate value ψ'T is calculated from に よ り '.

In step 64, the lateral acceleration YG and the longitudinal acceleration XG are read.

At step 65, it is determined whether the lateral acceleration YG is equal to or less than the set value A0 and the longitudinal acceleration XG is equal to or less than the set value A1.

In step 66, in step 65, YG ≦
When A0 and XG ≦ A1 are satisfied, the temperature corrected yaw rate value ψ'T calculated in step 63 is changed to the actual yaw rate value ψ'O
It is said.

In step 67, when the low roll / low pitch condition of step 65 is not satisfied, as shown in FIG.
The vehicle roll angle θRO is estimated from the lateral acceleration YG, and the roll correction coefficient KRO is calculated from the vehicle roll angle θRO by the following correction formula in the direction perpendicular to the vehicle plane (corresponding to the roll correction coefficient setting means d).

KRO = 1 · cos θRO In step 68,
As shown in FIG. 9, the vehicle pitch angle θPI is estimated from the longitudinal acceleration XG, and the pitch correction coefficient KPI is calculated from the vehicle pitch angle θPI by the following correction formula in the direction perpendicular to the vehicle plane.
Is calculated (corresponding to pitch correction coefficient setting means e).

KPI = 1 · cos θPI In step 69,
The actual yaw rate value ψ'O is calculated by the following equation using the temperature correction yaw rate value ψ'T, the roll correction coefficient KRO, and the pitch correction coefficient KPI (corresponding to the actual yaw rate value calculation means f).

Ψ′O = KRO · KPI · ψ′T [Detected yaw rate correction operation at low roll / low pitch] The correction of the detected yaw rate at low roll / low pitch is performed in the steps of FIG. 65
→ It is performed by the process flowing to step 66, and in step 66, the temperature corrected yaw rate value ψ'T is set to the actual yaw rate value ψ'O.

That is, when the roll and the pitch are low, the influence of the roll and the pitch on the yaw rate sensor output value Vψ 'is small. Conversely, the update of the data of the actual yaw rate value ψ'O is delayed due to the time required for the process of performing the roll / pitch correction.

Therefore, at the time of low roll and low pitch, if the temperature correction for the yaw rate sensor output value Vψ 'is performed, the data of the actual yaw rate value ψ'O is updated early.
The control responsiveness in the yaw rate feedback control using the actual yaw rate value ψ'O is not reduced.

Of course, in this case, the temperature drift correction coefficient K
1 eliminates the effect of temperature drift,
Further, the control sensitivity corresponding to the occurrence of the yaw rate can be ensured by the gain correction coefficient K2.

[Correction Action of Detected Yaw Rate at Roll / Pitch] The correction of the detected yaw rate when a roll or a pitch is generated is performed in the flow chart of FIG. 5 in steps 60 to 65 → step 67 → step 68 → step 69. Step 6
9, the temperature correction yaw rate value ψ'T and the roll correction coefficient K
Actual yaw rate value ψ'O by RO and pitch correction coefficient KPI
It is said.

Therefore, in addition to the temperature correction, the roll correction coefficient KRO can eliminate the offset effect of the yaw rate sensor output value Vψ 'due to the vehicle roll.
The offset effect of the yaw rate sensor output value Vψ 'due to the vehicle pitch can be removed by the pitch correction coefficient KPI.

As a result, a high control accuracy is ensured in the yaw rate feedback control using the actual yaw rate value 時 に 'O during traveling in which a large roll or a pitch is generated, and the target turning performance given by the target yaw rate ψ'M is obtained. be able to.

The effect will be described.

(1) In a yaw rate correction device detected by a yaw rate sensor 25 mounted on a vehicle, a roll correction coefficient KRO and a pitch which are always corrected in a direction perpendicular to a vehicle plane based on a lateral acceleration YG and a longitudinal acceleration XG. After determining the correction coefficient KPI, this roll correction coefficient KRO
And a yaw rate correction process for calculating an actual yaw rate value ψ′O based on the yaw rate sensor output value Vψ ′ from the yaw rate sensor 25 from the pitch correction coefficient KPI and the yaw rate sensor output value Vψ ′. The influence of the roll and the pitch is removed, and the reliability of the actual yaw rate value ψ'O can be improved.

In particular, this can be an effective correction means in a vehicle not equipped with an active suspension control system for suppressing a roll pitch during a turn.

(2) A temperature drift correction coefficient K1 is determined based on the detected temperature T and a previously measured temperature drift characteristic, and the actual yaw rate is determined based on the temperature drift correction coefficient K1 and the yaw rate sensor output value V２５ 'from the yaw rate sensor 25. Since the apparatus performs the detected yaw rate correction processing for calculating the value と し た ′ O, the yaw rate sensor output value Vψ ′
The effect of temperature drift can be eliminated.

(3) The gain correction coefficient K2 is determined based on the yaw rate sensor output value Vψ 'corresponding to the actual yaw rate, and the actual yaw rate value ψ' is determined based on the gain correction coefficient K2 and the yaw rate sensor output value Vψ 'from the yaw rate sensor 25. Since the apparatus performs the detected yaw rate correction processing for calculating 'O', the control sensitivity according to the occurrence of the yaw rate detected by the yaw rate sensor output value Vψ 'can be ensured.

(4) The temperature correction yaw rate value ψ'T is calculated first, and it is determined whether or not the roll / pitch correction is performed. When the roll / pitch correction is low, the temperature correction yaw rate value ψ'T is set to the actual yaw rate. Since the apparatus performs processing with the value ψ'O, the data of the actual yaw rate value ψ'O is updated early when traveling with low roll and low pitch, and the yaw rate feedback control using the actual yaw rate value ψ'O is performed. Control responsiveness can be ensured.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to the embodiment, and even if there are changes and additions without departing from the gist of the invention, the invention is included in the invention. It is.

For example, in the embodiment, an example in which the detected yaw rate correction device is applied to a four-wheel steering vehicle has been described. The present invention can be applied to those using an actual yaw rate as control information.

In the embodiment, the example in which the roll and the pitch are detected by the acceleration sensor is described. However, the roll and the pitch may be detected by using a stroke sensor of the suspension.

[0071]

As described above, according to the present invention, there is provided a yaw rate correction device for detecting a yaw rate detected by a yaw rate sensor mounted on a vehicle, wherein a yaw rate correction device detects a vehicle plane inclined based on a roll equivalent value and a pitch equivalent value. Vertical direction
The output value of the yaw rate sensor around the axis
Actual yaw rate value calculating means for determining a roll correction coefficient and a pitch correction coefficient to be corrected to values around the vertical axis, and calculating an actual yaw rate value from the roll correction coefficient and the pitch correction coefficient and a yaw rate sensor output value from the yaw rate sensor. Therefore, the effect of the roll and the pitch during the running of the vehicle on the output value of the yaw rate sensor is removed, and the effect that the reliability of the actual yaw rate value can be improved can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims showing a detected yaw rate correction device of the present invention.

FIG. 2 is an overall system diagram showing a four-wheel steering vehicle to which the detected yaw rate correction device of the embodiment is applied.

FIG. 3 is a cross-sectional view of the electric steering device of the embodiment device.

FIG. 4 is a flowchart illustrating a flow of a rear wheel steering angle control operation performed by a controller of the embodiment device.

FIG. 5 is a flowchart illustrating a flow of a detected yaw rate correction processing operation performed by a controller of the embodiment device.

FIG. 6 is a characteristic diagram of a temperature drift correction coefficient.

FIG. 7 is a characteristic diagram of a gain correction coefficient.

FIG. 8 is a diagram illustrating a roll angle of a yaw rate sensor.

FIG. 9 is a diagram illustrating a pitch angle of a yaw rate sensor.

FIG. 10 is a diagram showing an attached state of a yaw rate sensor.

FIG. 11 is a characteristic diagram of an output value of a yaw rate sensor with respect to generation of a roll angle and a pitch angle .

[Explanation of symbols]

a yaw rate sensor b roll equivalent value detecting means c pitch equivalent value detecting means d roll correction coefficient setting means e pitch correction coefficient setting means f actual yaw rate value calculating means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI B62D 107: 00 111: 00 113: 00 137: 00 (58) Investigated field (Int.Cl. ⁷ , DB name) G01P 15 / 14 B62D 6/00 G01P 15/00 B62D 101: 00 B62D 103: 00 B62D 107: 00 B62D 111: 00 B62D 113: 00 B62D 137: 00

Claims (1)

(57) [Claims] 1. A yaw rate sensor installed in a direction perpendicular to a plane of a vehicle and detecting a yaw rate applied to the vehicle, a roll equivalent value detecting means for detecting a roll equivalent value applied to the vehicle, and detecting a pitch equivalent value applied to the vehicle. Estimating the vehicle roll angle based on the pitch equivalent value detection means and the detected roll equivalent value ,
Based on this vehicle roll angle , the vehicle plane
Running the yaw rate sensor output value around the vertical axis
Roll correction coefficient setting means for determining a roll correction coefficient for correcting to a value about a vertical axis orthogonal to the road surface, and a vehicle pitch angle is estimated based on the detected pitch equivalent value ,
Based on this vehicle pitch angle , the vehicle is
Running the yaw rate sensor output value around the vertical axis
Pitch correction coefficient setting means for determining a pitch correction coefficient for correcting a value around a vertical axis perpendicular to the road surface, and actual yaw rate value calculation means for calculating an actual yaw rate value based on a yaw rate sensor output value, a roll correction coefficient, and a pitch correction coefficient A detection yaw rate correction device, comprising: