JP3329835B2 - Vehicle yaw moment control 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 yaw moment control device for optimally controlling the yaw movement performance of a vehicle.

[0002]

2. Description of the Related Art Conventionally, for example, a desired differential limiting force is controlled by controlling the engagement force of a clutch provided between input and output members of a differential according to a vehicle state, a difference between left and right wheel rotational speeds, and the like by electronic control. The resulting electronically controlled differential limiting device is known from Japanese Patent Application Laid-Open No. 1-204826.

Conventionally, an auxiliary steering angle actuator for providing an auxiliary steering angle to at least one of the front and rear wheels by external control is provided, and a vehicle side slip angle generated at the time of steering according to a steering angle or a vehicle speed is reduced to zero. An electronically controlled auxiliary steering angle control device for controlling the auxiliary steering angle so as to match them is disclosed in Japanese Patent Publication No. 60-441.
It is known in, for example, Japanese Patent Publication No. 85.

[0004]

However, in the former electronically controlled differential limiting device, when the clutch is engaged and the driving force (engine torque) transmitted to the right and left driving wheels is different, the yaw acting on the vehicle is different. Although an additional yaw moment is generated for the moment amount, the vehicle does not generate an additional yaw moment according to the sideslip angle using the sideslip angle as a control input. Cannot be secured.

Further, in the latter electronic control auxiliary steering angle control device, although the skid angle of the vehicle generated as a result of steering can be reduced to zero, the skid angle is not included in the control input. Therefore, as described above, the stability of the vehicle cannot be sufficiently ensured.

For example, even if a side slip angle occurs due to disturbance such as a cross wind or road surface unevenness, if the vehicle is running with the steering wheel kept at the neutral position, the auxiliary steering angle control is not performed unless there is a steering input, and the vehicle is stable. Sex will be impaired.

On the other hand, a static margin (hereinafter referred to as SM) is used as an index that theoretically indicates vehicle stability.
(See page 55 of "Vehicle Motion and Control" published by Kyoritsu Shuppan Co., Ltd.)

If the cornering power of the front and rear wheels is Cf, Cr, and the distance from the center of gravity of the vehicle to the front and rear wheels is a, b, SM = b × Cr−a × Cf (1) Become. Physically, the numerical value of SM has a meaning of a yaw moment change amount with respect to a change in the side slip angle of the vehicle body. In other words, the yaw moment acting on the vehicle is Mφ,
If the sideslip angle is β, SM = δMφ / δβ (2) The stability of the vehicle increases as the value of SM increases, and when the value of SM decreases and becomes negative, the stability of the vehicle decreases.

Here, the reason why the value of SM tends to be negative due to decrease is that when the term b × Cr becomes a small value in equation (1), for example, cornering of the rear wheel during acceleration in an FR vehicle. When the power Cr decreases due to an excessive transmission driving force, or when the terms b × Cr and a × Cf both take small values in the equation (1), for example, at the time of high lateral acceleration running or high speed running When the cornering powers Cf and Cr of the front and rear wheels are reduced, the value of SM is more likely to be negative than when the load transfer ratio on the rear wheel side is large in the setting of the vehicle. The reason why the cornering power decreases during such running is that the cornering power shows a characteristic of sharply decreasing as shown in FIG. 5 in a region where the tire slip angle is large. That is, when the SM value decreases and tends to be negative, it is necessary to increase the SM value to secure the stability of the vehicle.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. In a yaw moment control device for controlling a yaw motion of a vehicle, the yaw moment control device controls the vehicle while allowing the occurrence of a side slip angle accompanying a running condition. Always maintain stability and stability
During low-speed turns with high
In low-quality high-speed driving areas, high lateral acceleration areas, acceleration, etc.
It is an object to surely maintain vehicle stability .

[0011]

In order to solve the above-mentioned problems, a vehicle yaw moment control apparatus according to the present invention uses a side slip angle of a vehicle body as a control input and sets a side slip angle as a vehicle speed or a steering angle.
Value corrected to increase in accordance with at least one increase
Is the amount of additional yaw moment that ensures vehicle stability.
And a means for controlling to impart Te.

That is, as shown in the claim correspondence diagram of FIG. 1, an additional yaw moment generating means a for generating an additional yaw moment with respect to the amount of yaw moment acting on the vehicle, a side slip angle or a side slip angle equivalent amount during running of the vehicle. Angle detection means b for detecting the vehicle speed or the steering angle.
Corrected to increase in accordance with at least one of
An additional yaw moment amount values stability of the vehicle is ensured
And an additional yaw moment control means d for outputting a command for obtaining the additional yaw mont amount to the additional yaw moment generating means a.

[0013]

[Action] during traveling, the side slip angle detecting means b, the side slip angle or the side slip angle substantial amount of traveling of the vehicle is detected, the additional yaw moment amount calculation means c, sideslip
The angle according to at least one of the vehicle speed or the steering angle
The value corrected so as to increase is calculated as an additional yaw moment amount at which the stability of the vehicle is ensured. In the additional yaw moment control means d, a command to obtain the additional yaw mont amount of the calculation result is sent to the additional yaw moment generation means a. Is output.

Accordingly, a yaw moment component acting on the vehicle during traveling is added to the yaw moment component by the control in addition to the lateral force acting on the tire, and the side slip angle increases while allowing the occurrence of the side slip angle. The effect of always securing a restoring moment with respect to a change in direction is achieved by performing control for applying an additional yaw moment that ensures the stability of the vehicle in accordance with the detected amount of sideslip angle.

The addition of the yaw moment component increases the yaw moment change amount δMφ with respect to the vehicle body slip angle change δβ, as is apparent from the above equation (2) expressed by SM = δMφ / δβ. The value of SM becomes a large value, and the stability of the vehicle is increased. Also, the vehicle speed or
Added with a value that increases as at least one of the steering angles increases
Since the amount of yaw moment is calculated, the value of SM is positive.
Steering responsiveness during low-speed turning
And high-speed running where the SM value would normally be negative
SM value in line area, high lateral acceleration area, acceleration, etc.
Is prevented from becoming negative, and the stability of the vehicle is ensured.

[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 rear wheel drive vehicle to which the yaw moment control device according to the embodiment of the present invention is applied.
A rear-wheel drive vehicle as an applicable vehicle is provided with an engine 5, a transmission 6, a propeller shaft 7,
The driving force is transmitted via a left and right driving force distribution mechanism 8 (corresponding to an additional yaw moment generating means) and left and right drive shafts 9 and 10.

The yaw moment control device according to the embodiment has a pair of hydraulic multi-plate clutches 11 and 12 on the left and right sides, and the driving forces FL and FR transmitted to the left and right rear wheels 3 and 4 according to the clutch engagement force. The right and left driving force distribution mechanism 8 that is generated, a hydraulic unit 13 that generates an independent control hydraulic pressure serving as a clutch engagement force for each of the pair of hydraulic multi-plate clutches 11 and 12, and an input signal from each sensor. A hydraulic control unit 13 includes a left rear wheel side hydraulic control valve 14 and a right rear wheel side hydraulic control valve 15 that outputs a control command to a controller 16.

The controller 16 includes a vehicle speed sensor 17 and a steering angle sensor 18 for detecting a vehicle running state, a sideslip angle sensor 19 for detecting a sideslip angle of the vehicle body (corresponding to sideslip angle detecting means), and a propeller shaft 7. Sensor signals from a rotation speed sensor 20 that detects the rotation speed, and left wheel speed sensors 21 and right wheel speed sensors 22 that detect the rotation speeds of the left and right rear wheels 3 and 4 are input.

The side slip angle sensor 19 is obtained by optically detecting a longitudinal component and a lateral component of the vehicle speed with respect to the ground, and detects the sideslip angle of the vehicle from the respective values. More specifically, if the front-back direction component is Vx and the left-right direction component is Vy, the sideslip angle β is β = tan ⁻¹ (Vy / Vx).

The operation will be described.

FIG. 3 is a flowchart showing the flow of the additional yaw moment control processing operation performed by the controller 16, and each step will be described below.

In step 30, the vehicle speed V and the steering angle θ are read from the vehicle speed sensor 17 and the steering angle sensor 18. In step 31, the vehicle speed V is calculated based on the map shown in FIG.
And a gain K corresponding to the steering angle θ is calculated. FIG.
Is set such that the gain K increases as the vehicle speed V and the steering angle θ increase.
This is because the lateral acceleration of the vehicle increases as the steering angle θ increases, and the SM value decreases.

In step 32, the side slip angle β of the vehicle body is read from the side slip angle sensor 19, and in step 33,
A yaw moment amount ΔMφ to be generated is calculated based on the gain K and the sideslip angle β (corresponding to an additional yaw moment amount calculating means).

The calculation formula is ΔMφ = K × β (3), and this formula (3) is obtained by the above formula (2) (SM = δMφ / δ
β) can be obtained by rewriting SM = K, δMφ = ΔMφ, δβ = β, and the gain K corresponds to the value of SM.

In step 34, a left and right wheel driving force difference dF is calculated from the yaw moment amount ΔMφ. The left and right wheel driving force difference dF is dF = ΔMφ / Tr. Here, Tr is a tread of the left and right rear wheels 3 and 4.

In step 35, the driving forces FL and FR of the left and right rear wheels 3 and 4 are calculated from the total driving force FTOTAL generated in the left and right rear wheels 3 and 4 and the driving force difference dF of the left and right wheels by the following equations. FL = 0.5 × (FTOTAL + dF) FR = 0.5 × (FTOTAL−dF) Here, how to determine the total driving force FTOTAL will be described. The driving forces FL and FR of the left and right rear wheels 3 and 4 are controlled by the hydraulic multiple disc clutch 1
It is determined by the pressing pressure of 1,12. Furthermore, it is sufficient if the torque generated on the engine side 5, 6 is known, but since the torque generated on the engine side 5, 6 is not actually known, the difference between the rotational speeds of the right and left rear wheels 3, 4 and the propeller shaft 7 is an allowable value. By controlling the pressing pressure so as not to exceed the torque, the torque generated on the engine side 5, 6 is controlled to be transmitted to the left and right rear wheels 3, 4. Therefore, each hydraulic multi-plate clutch 11,
The pressing pressure of No. 12 is “the rotation difference between the propeller shaft 7 and the left and right rear wheels 3, 4” and “the driving force difference d to be generated between the right and left wheels”.
F ", the total driving force FTOTAL
Is determined by the “rotational difference between the propeller shaft 7 and the left and right rear wheels 3 and 4”.

In step 36, each hydraulic multi-disc clutch 1 is operated based on each of the driving forces FL and FR calculated in step 35.
Pressing pressures to the pressures 1 and 12 are determined, and a control command value for obtaining the pressing pressure is output to the left rear wheel side hydraulic control valve 14 and the right rear wheel side hydraulic control valve 15 of the hydraulic unit 13. Steps 34 to 36 correspond to additional yaw moment control means.

Therefore, a yaw moment component acting on the vehicle during traveling is added to the yaw moment component by the control in addition to the lateral force acting on the tires. The action of always securing the restoring moment with respect to the change in the direction in which the yaw moment ΔMφ is performed in accordance with the magnitude of the side slip angle β is achieved.

The addition of the yaw moment component increases the yaw moment change amount δMφ with respect to the vehicle body side slip angle change δβ, as is apparent from the above equation (2) expressed by SM = δMφ / δβ. The value of SM becomes a large value, and the stability of the vehicle is increased.

In addition, the vehicle traveling state is detected based on the vehicle speed V and the steering angle θ, and control is performed such that the gain K corresponding to the value of SM increases as the vehicle speed V increases and the steering angle θ increases. Therefore, at the time of running at high lateral acceleration or at high speeds, it is the same as the case where the target value of SM is set to a large value. At the time of acceleration, the change speed of the target value of SM becomes large, and the response to acceleration is improved Yaw moment amount ΔMφ
Is increased so that even during such traveling, S
The value of M is prevented from becoming negative.

As described above, in the yaw moment control device of the embodiment, the following effects are exhibited.

(1) In a vehicle yaw moment control device for controlling the yaw movement of a vehicle, a control is performed in which a vehicle side slip angle β is used as a control input and a yaw moment amount ΔMφ is applied in proportion to the magnitude of the side slip angle β. Therefore, the stability of the vehicle can always be maintained while allowing the occurrence of the sideslip angle accompanying the running condition.

(2) Since the running state of the vehicle is detected based on the vehicle speed V and the steering angle θ, the gain K increases as the vehicle speed V increases and the steering angle θ increases.
Steering responsiveness is ensured during low-speed turning where the value of SM is positive, and in high-speed running regions, high lateral acceleration regions, acceleration, etc. where the value of SM is normally negative during normal turning. In this case, the value of SM is prevented from becoming negative, and the stability of the vehicle is 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, the left and right driving force distribution mechanism has been described as an example of the yaw moment generating means. However, any means that can apply an additional yaw moment in accordance with the side slip angle, for example, the left and right independent braking force An applying mechanism, a front and rear wheel driving force distribution mechanism, an auxiliary steering angle applying mechanism, and the like may be used, and these means may generate an additional yaw moment during acceleration, deceleration, high lateral acceleration, or the like. Due to the limited area in which a plurality can be obtained, a plurality of combinations may be applied.

In the embodiment, an example of the sideslip angle sensor for directly detecting the sideslip angle of the vehicle body has been shown as the sideslip angle detecting means. For example, the output values from the longitudinal acceleration sensor and the lateral acceleration sensor of the vehicle body are integrated. The vehicle speed component in the front-rear direction and the vehicle speed component in the left-right direction may be obtained, and the sideslip angle may be obtained from both.

In the embodiment, the value of the gain K is set to the vehicle speed V and the steering
Although the preferred embodiment for varying the angle theta, the vehicle speed V
An example in which the gain K is made variable by one of the steering angles θ
May be.

[0040]

In the present invention, as has been described above, according to the present invention is to at yaw moment control device for a vehicle for controlling the yawing motion of the vehicle, a control input side slip angle of the vehicle body, YokoNamera
Angle in accordance with at least one of vehicle speed or steering angle
Since the stability of the vehicle corrected value to increase is a means for controlling to be added as additional yaw moment amount to be reserved Te, the stability of the vehicle while allowing the occurrence of accompanying slip angle on the driving situation Low speed with high stability while always keeping
Steering responsiveness is ensured when turning, and stability is low.
In high-speed running areas, high lateral acceleration areas, acceleration, etc.
The effect that the vehicle stability can be maintained can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims showing a yaw moment control device for a vehicle according to the present invention.

FIG. 2 is an overall system diagram showing a rear wheel drive vehicle to which the yaw moment control device of the embodiment is applied.

FIG. 3 is a flowchart showing a flow of an additional yaw moment control processing operation performed by a controller of the yaw moment control device of the embodiment.

FIG. 4 is a gain characteristic diagram with respect to a vehicle speed and a steering angle in the apparatus according to the embodiment.

FIG. 5 is a diagram showing cornering power characteristics.

[Explanation of symbols]

 a additional yaw moment generating means b sideslip angle detecting means c additional yaw moment amount calculating means d additional yaw moment controlling means

Continuation of the front page (56) References JP-A-2-95982 (JP, A) JP-A-62-299430 (JP, A) JP-A-62-4674 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) B60K 23/04

Claims (1)

(57) [Claims] An additional yaw moment generating means for generating an additional yaw moment with respect to a yaw moment amount acting on a vehicle; a side slip angle detecting means for detecting a side slip angle or a side slip angle equivalent while the vehicle is traveling ; To increase at least one of vehicle speed or steering angle
An additional yaw moment amount calculating means for calculating a value corrected so as to increase in accordance with the additional yaw moment amount for ensuring the stability of the vehicle; and a command for obtaining the additional yaw moment amount to the additional yaw moment generating means. A yaw moment control device for a vehicle, comprising: additional yaw moment control means for outputting.