JPH06273444A - Correction apparatus of detected yaw rate - Google Patents

Abstract

PURPOSE:To enhance the reliability of an actual yaw-rate value by a method where the actual yaw-rate value is computed on the basis of a yaw-rate-sensor output value and of individual roll and pitch correction factors and the influence of a roll and a pitch is removed. CONSTITUTION:A motor 19, a fail-safe solenoid 20 and the like are installed at a rack tube 17 in which a rack shaft 12 connecting a part between rear wheels 9, 10 has been inserted. A controller 26 to which signals from individual subsensors and main sensors 21 to 24 for a vehicle velocity, a front-wheel steering angle and a rear steering angle, from a yaw-rate sensor 25, from a transverse acceleration sensor 28 which detects a roll-rate equivalent value and from a front-and-rear acceleration sensor 29 which detects a pitch-rate equivalent value are input drives 3 and controlls the solenoid 20. When a vehicle is running, the sensor 25 which has been installed perpendicularly to the plane of the vehicle, detects a yaw rate which is applied to the vehicle. The controller 26 decides a roll correction factor and a pitch correction factor which assist in a direction always perpendicular to the plane of the vehicle on the basis of the individual roll-rate and pitch-rate equivalent values, and it computes an actual yaw-rate value on the basis of the output value of the sensor 25.

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 system or the like which gives an auxiliary steering angle by yaw rate feedback control when steering front wheels.

[0002]

2. Description of the Related Art Conventionally, as a detected yaw rate correction device applied to a four-wheel steering system that gives an auxiliary steering angle to rear wheels by yaw rate feedback control at the time of steering front wheels, for example, Japanese Patent Application Laid-Open No. 62-261575 has been disclosed. The device is known.

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

[0004]

However, the above-mentioned conventional detected yaw rate correction device is a device for correcting the zero point of the output value of the yaw rate sensor when the vehicle stop state is detected. Although it is possible to cope with the change over time of the yaw rate sensor in which the zero point offset gradually occurs,
If the yaw rate sensor output value changes due to the roll rate or pitch rate when the vehicle rolls or pitches, it cannot be handled.For example, the actual yaw rate value matches the target yaw rate value. In the rear wheel steering angle control by the yaw rate feedback to be performed, the actual yaw rate value with an error is used as the control information, which directly affects the control and causes a decrease in the control accuracy.
This will deteriorate the turning performance of the vehicle.

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

For example, looking at the characteristics of the yaw rate sensor output value from the yaw rate sensor when the roll rate and the pitch rate are respectively applied when the yaw rate is zero and there is no load, as shown in FIG. The sensor output value changes as shown by the one-dot chain line characteristic, the yaw rate sensor output value changes as shown by the two-dot chain line characteristic when the pitch rate is added, and it is erroneously detected that yaw rate occurs when roll or pitch is added. To do.

Therefore, when the roll and the pitch occur at the same time when the yaw rate occurs during the actual turning, the output value of the yaw rate sensor becomes a value offset from the true value.

The present invention has been made in view of the above problems, and an object thereof is to detect a yaw rate sensor output value with respect to a yaw rate sensor output value in a detection yaw rate correction device detected by a yaw rate sensor mounted on a vehicle. The purpose is to improve the reliability of the actual yaw rate value by eliminating the effects of roll and pitch while the vehicle is running.

[0009]

In order to solve the above-mentioned problems, in the detected yaw rate correction device of the present invention, a roll correction coefficient and a roll correction coefficient for always correcting the vehicle plane based on the roll rate equivalent value and the pitch rate equivalent value, An actual yaw rate value calculating means for determining a pitch correction coefficient and calculating an actual yaw rate value from the roll correction coefficient, the pitch correction coefficient and the yaw rate sensor output value from the yaw rate sensor is provided.

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 plane of the vehicle and detects a yaw rate applied to the vehicle, and a roll rate which detects a roll rate equivalent value applied to the vehicle. Corresponding value detecting means b, pitch rate equivalent value detecting means c for detecting a pitch rate equivalent value applied to the vehicle, and roll correction for determining a roll correction coefficient for always correcting in the vertical direction with respect to the vehicle plane based on the roll rate equivalent value. Coefficient setting means d,
Pitch correction coefficient setting means e that determines a pitch correction coefficient that is always corrected in the vertical direction with respect to the vehicle plane based on the pitch rate equivalent value, and an actual yaw rate value is calculated by the yaw rate sensor output value, the roll correction coefficient, and the pitch correction coefficient. And a yaw rate value calculating means f.

[0011]

When the vehicle is traveling, the yaw rate sensor a installed vertically 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 determines a roll correction coefficient which is always a vertical correction with respect to the plane of the vehicle based on the roll rate equivalent value from the roll rate equivalent value detecting means b, and the pitch correction coefficient is set. In the means e, the pitch correction coefficient which is always the correction in the vertical direction with respect to the vehicle plane is determined based on the pitch rate equivalent value from the pitch rate equivalent value detecting means c.

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 and the roll correction coefficient and the pitch correction coefficient.

Therefore, at the time of turning when yaw rate occurs, and when roll rate and pitch rate occur at the same time, a roll correction coefficient and a pitch correction coefficient which are always corrected in the direction perpendicular to the vehicle plane are determined. Since the yaw rate sensor output value from the yaw rate sensor a is corrected using the correction coefficient to calculate the actual yaw rate value, the roll effect and the pitch effect are removed from the actual yaw rate value, and the reliability of the actual yaw rate value is reduced. Will increase.

As a result, for example, when this actual yaw rate value is used for 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 detection yaw rate correction device of the embodiment of the present invention is applied.

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

The steering of the rear wheels 9 and 10 is performed by the electric steering device 11. This rear wheel 9,
Between 10 is a rack shaft 12, side rods 13, 1.
4, the knuckle arms 15 and 16 are connected to the rack tube 17 in which the rack 12 is inserted.
8, a motor 19 and a fail-safe solenoid 20 are provided, and the motor 19 and the fail-safe solenoid 20 are provided.
Is 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 the yaw rate sensor a), a temperature sensor 27, a lateral acceleration sensor 28 (roll rate equivalent value detection). The drive is controlled by the controller 26 which inputs signals from the longitudinal acceleration sensor 29 (corresponding to the pitch rate equivalent value detecting means c) and the like.

FIG. 3 is a sectional view showing a concrete structure of the electric steering device 11.

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

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

The fail-safe solenoid 20 includes:
The lock pin 20a is provided so as to be movable back and forth, and when the electronic control system or the like fails, the lock pin 20a is fitted into the lock groove 12b formed in the rack shaft 12 so that the rack shaft 12 is moved to the rear wheels 9 and 10. It is fixed at a position that maintains the neutral rudder 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, and each step will be described below.

At step 40, the vehicle speed V, the steering 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 the later-described detected yaw rate correction processing shown in FIG. 5, and is set to the latest value stored in the memory.

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

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

That is, when θ · θ ′ ≧ 0, it is determined that the steering rudder angle changing direction is the increasing direction, and when θ · θ ′ <0, the steering rudder angle changing direction is switched back. It is determined to be the direction.

At step 43, θ · θ '≧ 0, and
When it is determined that the steering rudder angle changing direction is the increasing direction, the first-order lag time constant TO is set to TOp (<TOm) due to a low value for obtaining turning performance.

At step 44, θ · θ '<0, and
When it is judged that the steering rudder angle changing direction is the reverse direction, the first-order lag time constant TO is set to TOm (> TOp) which is a high value for achieving convergence.

At step 45, the target yaw rate ψ'M is calculated by the following equation from the target yaw rate steady value ψ'MO and the first-order delay time constant TO set at step 43 or step 44.

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

At step 47, the deviation ε according to the vehicle speed V
The proportional term KP and the differential term KD of are set based on 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 formula based on P and the differential term KD.

ΔrF / B = (KP + KD · S) · ε At step 49, the feedback rear wheel steering angle δrF / B at step 48 is converted to the motor rotation target value THi.

In step 50, the rear steering angle main sensor value δrS is converted into the 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.

At step 52, PW is issued in response to the output command.
The duty ratio of M is controlled, and the 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, and 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.

At step 61, the temperature drift correction coefficient K1 is calculated from the temperature T.

With respect to the temperature drift correction coefficient K1, the zero point change is measured by changing the temperature in a yaw rate unloaded state, and based on the measurement result, as shown in FIG.
Set as a coefficient for zero point correction that removes the effect of temperature drift.

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

Since the output from the yaw rate sensor 25 becomes dull 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 according to the yaw rate sensor output value Vψ '.

In step 63, the temperature drift correction coefficient K1, the gain correction coefficient K2, and the yaw rate sensor output value V
The temperature-corrected yaw rate value ψ′T is calculated from ψ ′.

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

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

In step 66, YG ≤
When A0 and XG ≤ A1 are satisfied, the temperature correction yaw rate value ψ'T calculated in step 63 is the actual yaw rate value ψ'O.
It is said that

At step 67, when the low roll / pitch condition at step 65 is not satisfied, as shown in FIG.
A vehicle roll angle θRO is estimated from the lateral acceleration YG, and a roll correction coefficient KRO is calculated from the vehicle roll angle θRO by a correction formula in a direction perpendicular to the following 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 vehicle pitch angle θPI is used to correct the pitch correction coefficient KPI by a correction formula in the direction perpendicular to the following vehicle plane.
Is calculated (corresponding to pitch correction coefficient setting means e).

KPI = 1 · cos θPI In step 69,
An actual yaw rate value ψ'O is calculated by the following formula from 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 calculating means f).

Ψ'O = KRO · KPI · ψ'T [Correction of detected yaw rate during low roll / low pitch] Correction of detected yaw rate during low roll / low pitch is performed in steps 60 to 60 in the flowchart of FIG. 65
The process proceeds to step 66. In step 66, the temperature correction yaw rate value ψ'T is set to the actual yaw rate value ψ'O.

That is, when the roll is low and the pitch is low, the yaw rate sensor output value Vψ 'is less affected by the roll and the pitch. On the contrary, the data update of the actual yaw rate value ψ'O is delayed due to the time required for the roll / pitch correction process.

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 at an early stage.
The control response 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 can remove the effect of temperature drift,
Further, the gain correction coefficient K2 can ensure the control sensitivity according to the occurrence of yaw rate.

[Detection yaw rate correction operation during roll / pitch] The correction of the detection yaw rate when a roll or pitch occurs is performed in the flowchart 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
The actual yaw rate value ψ'O by RO and the pitch correction coefficient KPI
It is said that

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

As a result, a high control accuracy is ensured in the yaw rate feedback control using the actual yaw rate value ψ'O during traveling where a large roll or pitch occurs, 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 the yaw rate correction device detected by the yaw rate sensor 25 mounted on the vehicle, the roll correction coefficient KRO and the pitch which are always corrected in the vertical direction with respect to the vehicle plane based on the lateral acceleration YG and the longitudinal acceleration XG. The correction coefficient KPI is determined, and this roll correction coefficient KRO
Also, since the device for performing the detected yaw rate correction processing for calculating the actual yaw rate value ψ'O based on the pitch correction coefficient KPI and the yaw rate sensor output value Vψ 'from the yaw rate sensor 25, the vehicle is running with respect to the yaw rate sensor output value Vψ'. The roll and pitch effects are removed, and the reliability of the actual yaw rate value ψ'O can be improved.

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

(2) The temperature drift correction coefficient K1 is determined based on the detected temperature T and the temperature drift characteristic measured in advance, and the actual yaw rate is calculated based on the temperature drift correction coefficient K1 and the yaw rate sensor output value Vψ ′ from the yaw rate sensor 25. Since the device for performing the detected yaw rate correction processing for calculating the value ψ′O is used, the yaw rate sensor output value Vψ ′
The effect of temperature drift on 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 calculated based on the gain correction coefficient K2 and the yaw rate sensor output value Vψ' from the yaw rate sensor 25. Since the device for performing the detected yaw rate correction process for calculating “O” is used, it is possible to secure the control sensitivity according to the occurrence of the yaw rate detected by the yaw rate sensor output value Vψ ′.

(4) The temperature correction yaw rate value ψ'T is calculated first to determine whether or not roll / pitch correction is to be performed. When the roll / pitch is low, the temperature correction yaw rate value ψ'T is set to the actual yaw rate. Since the device that performs the processing with the value ψ'O is used, the yaw rate feedback control using the actual yaw rate value ψ'O can be performed by updating the data of the actual yaw rate value ψ'O at an early stage when running at low roll and low pitch. It is possible to secure the control responsiveness of.

Although the embodiments have been described above with reference to the drawings, the specific structure is not limited to the embodiments, and modifications and additions within the scope of the present invention are included in the present invention. Be done.

For example, in the embodiment, an example in which the detected yaw rate correction device is applied to a four-wheel steering vehicle is shown. However, it is an in-vehicle control system for controlling the yaw rate of the vehicle by the braking force distribution and the driving force distribution of the left and right wheels. It can be applied to the one using the actual yaw rate as the control information.

Further, in the embodiment, the example in which the roll and the pitch are detected by the acceleration sensor is shown, but the roll and the pitch may be detected by using the stroke sensor of the suspension.

[0071]

As described above, according to the present invention, in the detected yaw rate correction device detected by the yaw rate sensor mounted on the vehicle, the roll rate equivalent value and the pitch rate equivalent value are used for the plane of the vehicle. Since the roll correction coefficient and the pitch correction coefficient that are always vertical corrections are determined, the actual yaw rate value calculating means for calculating the actual yaw rate value from the yaw rate sensor output value from the roll correction coefficient and the pitch correction coefficient and the yaw rate sensor is provided, The effect that the roll and pitch influences the output value of the yaw rate sensor while the vehicle is traveling is eliminated, and the reliability of the actual yaw rate value can be improved.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing a detection yaw rate correction device of the present invention.

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

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

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

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

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

FIG. 7 is a gain correction coefficient characteristic diagram.

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 view showing a mounting state of a yaw rate sensor.

FIG. 11 is a yaw rate sensor output value characteristic diagram for the occurrence of roll rate and pitch rate.

[Explanation of symbols]

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

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Claims (1)

[Claims] 1. A yaw rate sensor, which is installed in a direction perpendicular to the plane of the vehicle and detects a yaw rate applied to the vehicle, a roll rate equivalent value detecting means for detecting a roll rate equivalent value applied to the vehicle, and a pitch rate equivalent to the vehicle. Pitch rate equivalent value detecting means for detecting a value, roll correction coefficient setting means for determining a roll correction coefficient which is always a vertical correction to the vehicle plane based on the roll rate equivalent value, and the vehicle plane based on the pitch rate equivalent value On the other hand, a pitch correction coefficient setting means for determining a pitch correction coefficient to be always corrected in the vertical direction, and an actual yaw rate value calculation means for calculating an actual yaw rate value from the yaw rate sensor output value, the roll correction coefficient and the pitch correction coefficient are provided. A detection yaw rate correction device characterized by the above.