JP2022037768A - Control device for vehicle - Google Patents

Abstract

To obtain a stable vehicle attitude.SOLUTION: A control device 10 for a vehicle 1 comprises a sensor 20 configured to detect a vehicle speed and a steering angle, a target pitch moment calculation unit 40a configured to calculate a target pitch moment based on the vehicle speed and the steering angle, and an actuator 30 configured to apply the target pitch moment to the vehicle. The target pitch moment calculation unit is configured to: estimate a roll angle while taking into account a response delay of the roll angle with respect to the steering angle on the basis of the vehicle speed and the steering angle; calculate a target pitch angle by multiplying the roll angle by a predetermined gain; and calculate, as the target pitch moment, a pitch moment required to bring a pitch angle to the target pitch angle, while taking into account a response delay of the pitch angle with respect to the pitch moment.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to a vehicle control device.

Vehicle body attitude control that detects the roll rate of the vehicle body with a sensor, calculates the target pitch rate based on the detected roll rate, and generates a pitch moment for the vehicle body so that the pitch rate of the vehicle body approaches the target pitch rate. The device is known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-071630

However, the transfer function of the pitch moment Mx (paragraph 0033) in Patent Document 1 is non-proper, in which the order of the numerator is higher than the order of the denominator. A non-proper transfer function can be implemented by using approximation or the like, but since it involves differentiation, there is a possibility that control may be delayed or disturbed. This means that a stable vehicle posture may not be obtained.

According to the present disclosure, the following are provided.
[Structure 1]
It ’s a vehicle control device.
Sensors configured to detect vehicle speed and steering angle,
A target pitch moment calculation unit configured to calculate a target pitch moment based on the vehicle speed and steering angle, and a target pitch moment calculation unit.
An actuator configured to give the target pitch moment to the vehicle,
Equipped with
The target pitch moment calculation unit is
Based on the vehicle speed and the rudder angle, the roll angle is estimated while considering the response delay of the roll angle with respect to the rudder angle.
The target pitch angle is calculated by multiplying the roll angle by a predetermined gain.
The pitch moment required to set the pitch angle to the target pitch angle is calculated as the target pitch moment while considering the response delay of the pitch angle with respect to the pitch moment.
A vehicle control unit that is configured as such.

A stable vehicle posture can be obtained.

It is a schematic whole view of a vehicle. It is a schematic diagram of the control device of the vehicle of the Example by this disclosure. It is a time chart explaining the target pitch angle of the Example by this disclosure. It is a diagram which shows the roll angle and the pitch angle when the steering angle is vibrated. It is a diagram of (A) a diagram of an Example according to the present disclosure, and (B) a diagram of a comparative example, showing a roll angle and a pitch angle when the steering angle is vibrated. It is a flowchart which shows the pitch control routine of the Example by this disclosure. It is a functional block diagram of the Example by this disclosure.

FIG. 1 shows the length direction axis X, the width direction axis Y, and the height direction axis Z, which are orthogonal to each other, of the vehicle 1 of the embodiment according to the present disclosure. The angle or posture of the vehicle 1 around the length direction axis X is represented by the roll angle φ. For example, the roll angle φ becomes zero when the right side portion and the left side portion of the vehicle 1 are at the same height position, becomes larger as the right side portion becomes lower than the left side portion, and becomes larger as the right side portion becomes higher than the left side portion. It gets smaller. On the other hand, the angle or posture of the vehicle 1 around the width direction axis Y is represented by the pitch angle ψ. For example, the pitch angle ψ becomes zero when the front side portion and the rear side portion of the vehicle 1 are at the same height position, becomes larger as the front side portion becomes lower than the rear side portion, and the front side portion becomes larger than the rear side portion. It gets smaller as it gets higher. The angle or posture of the vehicle 1 around the height direction axis Z is represented by the yaw angle θ. The vehicle 1 of the embodiment according to the present disclosure includes four or more vehicles.

Referring to FIG. 2, the control device 10 of the vehicle 1 of the embodiment according to the present disclosure includes a sensor 20, an actuator 30, and an electronic control unit 40.

The sensor 20 of the embodiment according to the present disclosure includes, for example, a vehicle speed sensor for detecting the vehicle speed V, a steering angle sensor for detecting the steering angle, and the like.

The actuator 30 of the embodiment according to the present disclosure applies a pitch moment to the vehicle 1. The actuator 30 of the embodiment according to the present disclosure includes, for example, a brake. For example, when the braking force by the brake is large, the pitch angle is large, and when the braking force by the brake is small, the pitch angle is small. In another embodiment (not shown), the actuator 30 includes a suspension capable of controlling damping force, an internal combustion engine or electric motor (motor generator) capable of controlling driving force, and the like.

The electronic control unit 40 of the embodiment according to the present disclosure comprises one or more processors 41, one or more memories 42, and an input / output (I / O) port 43, which are communicably connected to each other by a bidirectional bus. Be prepared. The memory 42 includes, for example, a ROM, a RAM, and the like. Various programs are stored in the memory 42, and various functions are realized by executing these programs in the processor 41. The sensor 20 and the actuator 30 described above are communicably connected to the input / output port 43 of the embodiment according to the present disclosure. Further, in the processor 21 of the embodiment according to the present disclosure, the actual steering angle is calculated based on the steering angle detected by the steering angle sensor.

By the way, if the vehicle 1 turns, for example, while traveling, the roll angle may fluctuate or vibrate, and the traveling stability of the vehicle 1 may decrease. Therefore, in the embodiment according to the present disclosure, roughly speaking, the pitch angle is controlled according to the roll angle to maintain the running stability of the vehicle 1.

Specifically, in the examples according to the present disclosure, the roll angle is first estimated. The transfer function of the estimated roll angle φ (rad) is expressed by, for example, the following equation (1).

Here, each coefficient is a value determined by the vehicle speed V (m / s) and the vehicle specifications, and is, for example, as follows.
a ₁₀ =-ml _r (C _f lC _r l) l _f gV ² + l _r mC _f C _r l _f (l _r + l _f ) ² g ²
a ₁₁ = l (mC _f l _f ² l _r + C _r (l _r ² m + I _z ) l _f + C _f I _z l _r ) Vg
a ₁₂ = I _z V ² l ²
b ₁₀ = g ² C _f l _r ² V ² C _r l _f m (l _r + l _f )
b ₁₁ = C _f l _r ² g ² VmC _r l _f (l _r + l _f )
b ₁₂ = C _f V ² gl _r I _z l
a ₂₀ : Roll rigidity
a ₂₁ : Roll damping
a ₂₂ : Roll inertia
b ₂₀ : Roll moment conversion coefficient
s: Laplace operator
m: Body mass (kg)
C _f : Normalized cornering power of front wheels (-)
C _r : Normalized cornering power of the rear wheels (-)
l: Wheelbase (m)
l _f : Distance between the center of gravity and the front wheel axle (m)
l _r : Distance between the center of gravity and the rear wheel axle (m)
g: Gravity acceleration (m / s ² )
I _z : Yaw moment of inertia (kg / m ² )
δ: Actual rudder angle (rad)

As can be seen from the equation (1), in the embodiment according to the present disclosure, the estimated roll angle φ is the vehicle speed V, the actual steering angle δ, and the response delay of the roll angle with respect to the actual steering angle δ (that is, the past steering angle and the past steering angle and Roll angle) and calculated based on. In the equation (1), the first term on the right side represents the conversion coefficient to the roll angle, and the second term on the right side represents the lateral acceleration.

In the embodiments according to the present disclosure, the target pitch angle ψ (rad) is then calculated. The target pitch angle ψ is obtained, for example, as an absolute value as a result of multiplying the estimated roll angle φ by the gain K, as shown in FIG. The gain K is not always constant and can be arbitrarily set according to the vehicle and the driving scene.

In the embodiment according to the present disclosure, the target pitch moment for setting the actual pitch angle to the target pitch angle is then calculated. The transfer function of the pitch angle ψ is expressed by the following equation (2) using, for example, the pitch moment My (Nm).

Here, each coefficient is a value determined by the vehicle specifications, and is, for example, as follows.
a ₃₀ : Pitch rigidity
a ₃₁ : Pitch attenuation
a ₃₂ : Pitch inertia
b ₃₀ : Pitch moment conversion coefficient

As described above, in the equation (2), the pitch angle is obtained based on the response delay of the pitch angle with respect to the pitch moment.

Therefore, assuming that ψ of the equation (2) is the target pitch angle described above and My is the target pitch moment, the target pitch moment My is expressed by the following equations (3) from the equations (1) and (2).

In the embodiment according to the present disclosure, as can be seen from the equation (3), a proper transfer function can be obtained. Therefore, control delays and control disturbances are limited. In this regard, if the target pitch moment is calculated using the detected roll angle, the order of the denominator of the transfer function of the target pitch moment becomes lower than the order of the numerator, and the transfer function is non-proper or unrealizable. Will be.

In the embodiment according to the present disclosure, the actuator 30 is then controlled so that the actual pitch moment becomes the target pitch moment.

4 and 5 (A) and 5 (B) show changes in the roll angle and the pitch angle when the steering angle is vibrated. In FIG. 4, the solid line shows an embodiment according to the present disclosure, and the broken line shows a comparative example in which a pitch moment is not applied by the actuator 30. On the other hand, FIG. 5A shows an embodiment according to the present disclosure, and FIG. 5B shows a comparative example. In FIGS. 5A and 5B, the solid line indicates the normalized roll angle, and the dotted line indicates the normalized pitch angle. In the embodiment according to the present disclosure shown in FIGS. 4 and 5 (A) and 5 (B), the actuator 30 is composed of an electric motor.

In the examples shown in FIGS. 4 and 5 (A) and 5 (B), the steering angle is varied along the sine curve. As a result, the normalized roll angle increases roughly from zero to one, then decreases to -1, and then increases to zero. On the other hand, the normalized pitch angle increases roughly from zero to one, then decreases toward zero, then increases toward one, and then decreases toward zero. Therefore, in FIG. 4, if the curve is close to the straight line connecting the point (0,0) and the point (1,1) and the straight line connecting the point (0,0) and the point (-1,1), the pitch It can be said that the angle is well synchronized with the roll angle, or the pitch angle responds well to the roll angle.

Referring to FIG. 4, in the examples according to the present disclosure, better responsiveness of the pitch angle is obtained as compared with the comparative example. In particular, good response of the pitch angle can be obtained at the initial stage of the change of the steering angle. This is also supported by FIGS. 5 (A) and 5 (B). Therefore, a stable posture of the vehicle 1 can be obtained.

FIG. 6 shows the pitch control routine of the embodiment according to the present disclosure. With reference to FIG. 6, in step 100, the roll angle is estimated. In the following step 101, the target pitch angle is calculated. In the following step 102, the target pitch moment is calculated. In the following step 103, the actuator 30 is controlled so that the pitch moment becomes the target pitch moment.

Therefore, according to the embodiment according to the present disclosure, as shown in the functional block diagram of FIG. 7, the control device 10 of the vehicle 1 has a sensor 20 configured to detect the vehicle speed and the steering angle, and the vehicle speed. The target pitch moment calculation unit 40a configured to calculate the target pitch moment based on the steering angle, and the actuator 30 configured to give the target pitch moment to the vehicle are provided. The pitch moment calculation unit estimates the roll angle based on the vehicle speed and the steering angle while considering the response delay of the roll angle with respect to the steering angle, and multiplies the roll angle by a predetermined gain to obtain the target pitch. The angle is calculated, and the pitch moment required to set the pitch angle to the target pitch angle is calculated as the target pitch moment while considering the response delay of the pitch angle with respect to the pitch moment.

1 Vehicle 10 Control device 20 Sensor 30 Actuator 40 Electronic control unit 40a Target pitch moment calculation unit

Claims (1)

It ’s a vehicle control device.
Sensors configured to detect vehicle speed and steering angle,
A target pitch moment calculation unit configured to calculate a target pitch moment based on the vehicle speed and steering angle, and a target pitch moment calculation unit.
An actuator configured to give the target pitch moment to the vehicle,
Equipped with
The target pitch moment calculation unit is
Based on the vehicle speed and the rudder angle, the roll angle is estimated while considering the response delay of the roll angle with respect to the rudder angle.
The target pitch angle is calculated by multiplying the roll angle by a predetermined gain.
The pitch moment required to set the pitch angle to the target pitch angle is calculated as the target pitch moment while considering the response delay of the pitch angle with respect to the pitch moment.
A vehicle control unit that is configured as such.

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