JP2021041829A - Vehicle control apparatus and vehicle control method - Google Patents

Abstract

To facilitate a vehicle to travel with a good riding comfort when the vehicle travels in a curve.SOLUTION: A vehicle control apparatus 1 includes: a curvature identification part 122 for identifying a curvature in a given point in a road in a progress direction of a vehicle V; and a target value determination part 123 for determining a target value of a control value for controlling the vehicle V so that lateral acceleration-deceleration that is lateral-direction acceleration-deceleration of the vehicle V in an evaluation section where the vehicle travels meets a given limiting condition over a limited time from a temporal point where the vehicle V passes the given point, the lateral acceleration-deceleration predicted on the basis of the curvature, and so that an evaluation function that includes a first term on the basis of a synthetic vector produced by synthesizing front-rear acceleration-deceleration that is a predicted value of acceleration-deceleration in a front-rear direction of the vehicle V in the evaluation section and the lateral acceleration-deceleration becomes a minimum value.SELECTED DRAWING: Figure 2

Description

The present invention relates to a vehicle control device and a vehicle control method for controlling the traveling of a vehicle.

A technique for controlling the acceleration / deceleration of a vehicle so that the driver's feeling when the vehicle passes a curve is known (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-014202

In the conventional technique, there is a problem that the lateral acceleration becomes too large when passing through a place having a large curvature, and the riding comfort may be deteriorated.

Therefore, the present invention has been made in view of these points, and an object of the present invention is to enable the vehicle to travel in a comfortable state when the vehicle travels on a curve.

In the vehicle control device of the first aspect of the present invention, the vehicle passes through a curvature specifying portion that specifies the curvature of a predetermined point on the road in the traveling direction of the vehicle and the predetermined point predicted based on the curvature. The lateral acceleration / deceleration, which is the lateral acceleration / deceleration of the vehicle in the evaluation section in which the vehicle travels for a finite time from the time point, satisfies a predetermined constraint condition, and the acceleration / deceleration of the vehicle in the front-rear direction in the evaluation section The target value of the control value for controlling the vehicle is determined so that the evaluation function including the first term based on the composite vector obtained by combining the predicted front-rear acceleration / deceleration and the lateral acceleration / deceleration becomes the minimum value. It has a target value determination unit.

In the vehicle control method of the second aspect of the present invention, a step of specifying the curvature of a predetermined point on the road in the traveling direction of the vehicle, which is executed by a computer, and the vehicle at the predetermined point predicted based on the curvature. The lateral acceleration / deceleration, which is the lateral acceleration / deceleration of the vehicle in the evaluation section in which the vehicle travels for a finite time from the time when the vehicle passes, satisfies a predetermined constraint condition, and the vehicle is in the front-rear direction in the evaluation section. The target value of the control value for controlling the vehicle so that the evaluation function including the first term based on the composite vector obtained by combining the front-rear acceleration / deceleration, which is the predicted value of the acceleration / deceleration, and the lateral acceleration / deceleration becomes the minimum value. Has a step to determine.

According to the present invention, when the vehicle travels on a curve, the effect is that the vehicle can travel in a state of good riding comfort.

It is a figure for demonstrating the outline of the vehicle which concerns on this embodiment. It is a figure which shows the structure of a vehicle.

[Overview of Vehicle V]
FIG. 1 is a diagram for explaining an outline of the vehicle V according to the present embodiment. The vehicle V has an ACC (Adaptive Cruise Control) function, and can travel while automatically controlling the vehicle speed based on the surrounding conditions such as the speed of the preceding vehicle or the shape of the road.

FIG. 1 schematically shows how the vehicle V travels on a curved portion of the road. The broken line arrow in FIG. 1 indicates the direction in which the acceleration is generated. The vehicle V calculates the vehicle speed at the point where the vehicle V reaches t2 to t8 at each predetermined time interval thereafter, based on the state of the vehicle V at the time t1 in FIG. 1 and the control input. Based on the state of the vehicle V at time t2 and the control input, the vehicle V updates the vehicle speed at the point where the time t3 to t8 is reached, and the vehicle speed at the point where the time t9 (not shown) next to the time t8 is reached. Is calculated. In the present specification, the value of the control input is referred to as a control value.

When the vehicle V determines the vehicle speed in this way, the vehicle V starts decelerating before reaching the curved section, and in the curved section, acceleration is generated in the outward direction of the curve. After passing the curved section, the vehicle V starts accelerating toward the front.

The vehicle V starts deceleration before entering the curved section, and combines the vector of the acceleration / deceleration in the front-rear direction and the vector of the acceleration / deceleration in the lateral direction so that the lateral acceleration in the curved section does not become too large. The vehicle speed is determined using the combined vector. Although the details will be described later, in the vehicle V, the evaluation function including the composite vector has a predetermined value (for example, the minimum value) under the constraint condition that the lateral acceleration in the curved section is equal to or less than the predetermined upper limit value. Determine the control value that affects the vehicle speed.

The control values that affect the vehicle speed are, for example, acceleration / deceleration, engine torque, and vehicle speed itself. The vehicle V uses the evaluation function to obtain the optimum control input within a finite time after the current time is set as the initial time of the optimum control problem, and the initial value of the obtained optimum control input is the control input of the actual vehicle V. Used as. For example, when the current time is t1 and the finite time is T, the optimum control inputs u (t1), u (t2), ..., U (t1 + T) up to t1 + T are calculated, and u (t1) is input as control. Used as. At the next time t2, the optimum control input up to t2 + T is similarly obtained, and the initial value u (t2) is used as the control input. The vehicle V travels while repeating such an operation.

[Vehicle V configuration]
FIG. 2 is a diagram showing the configuration of the vehicle V. The vehicle V has a vehicle control device 1, an operation unit 2, and a control target 3. The vehicle control device 1 is a device for controlling the speed of a vehicle, and is included in, for example, an ECU (Electronic Control Unit). Details of the vehicle control device 1 will be described later.

The operation unit 2 is an operation panel that accepts the driver's operation. The operation unit 2 notifies the vehicle control device 1 of the input operation content.

The control target 3 is a device controlled based on a control value determined by the vehicle control device 1, and is, for example, an engine, a fuel injection device, an auxiliary brake (for example, a compression release brake, an exhaust brake, a retarder), or a transmission.

The vehicle control device 1 has a storage unit 11 and a control unit 12. The control unit 12 has a reception unit 121, a curvature specifying unit 122, and a target value determining unit 123.

The storage unit 11 has a storage medium such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and stores various types of data. The storage unit 11 also stores a program executed by the control unit 12.

The control unit 12 has, for example, a CPU (Central Processing Unit). The control unit 12 functions as a reception unit 121, a curvature specifying unit 122, and a target value determination unit 123 by executing the program stored in the storage unit 11.

The reception unit 121 receives the operation content input from the operation unit 2. The reception unit 121 notifies the part related to the operation content in the control unit 12 of the received operation content. The reception unit 121 receives, for example, a desired characteristic that is a traveling characteristic desired by the occupant of the vehicle V. The reception unit 121 notifies the target value determination unit 123 of the received desired characteristic.

The curvature specifying unit 122 specifies the curvature of a predetermined point on the road in the traveling direction of the vehicle V. The predetermined point is, for example, the point where the vehicle V is traveling. The curvature specifying unit 122 specifies the curvature by referring to map information including information on the curvature of the road stored in the storage unit 11, for example. The curvature specifying unit 122 may specify the curvature by referring to the map information acquired from the external server via the communication line.

The target value determination unit 123 determines an evaluation section in which the vehicle V travels for a finite time from the time when the vehicle V passes a predetermined point (for example, a section in which the vehicle V is expected to reach between the time t1 and the time t8 in FIG. ), The vehicle V is controlled so that the evaluation function including the first term based on the composite vector of the front-rear acceleration / deceleration and the lateral acceleration / deceleration, which is the predicted value of the acceleration / deceleration in the front-rear direction of the vehicle V, becomes the minimum value. Determine the target value of the control value to be used. The evaluation function may further include a second term based on the difference between the preset speed at a predetermined point and the target speed corresponding to the target value. When the target value is determined by the target value determining unit 123, the vehicle speed, which is a state variable, is determined.

When determining the target value based on the evaluation function, the target value determining unit 123 determines the target value so that the lateral acceleration / deceleration, which is the lateral acceleration / deceleration of the vehicle V, satisfies a predetermined constraint condition. The constraint condition is, for example, that it is within the maximum allowable acceleration / deceleration. The maximum acceleration / deceleration is set so as to match the desired characteristics notified from, for example, the reception unit 121. When the target value determining unit 123 determines the target value using such a constraint condition, it is possible to prevent the lateral acceleration / deceleration from becoming too large.

The evaluation function used by the target value determination unit 123 is represented by, for example, the following equation. The target value determination unit 123 determines the target value so that the value of the following evaluation function is minimized.

In the above equation, G _x is the front-rear acceleration / deceleration at the target setting point for determining the target value, G _y is the lateral acceleration / deceleration at the target setting point, v _t is the vehicle speed of the vehicle V at the time t, v. _d is a preset speed set as the speed at the target setting point. v _d is a speed set by, for example, the ACC function, and is determined based on the speed of the preceding vehicle. w ₁ is the first weighting factor of the first term including the composite vector. w ₂ is the second weighting coefficient of the second term including the square of the difference between the set speed and the speed corresponding to the target value.

ここで、Ｘ＝［ｘ ｖ］^Ｔである。また、ｘは車両の位置、ｖは車速、λは空気抵抗係数、Ｓは車両前面投影面積、μは転がり抵抗係数、ｇは重力加速度、θは道路の勾配、ｕ（ｔ）は制御入力である。
上記の状態方程式に基づいて、前後方向の加減速度Ｇ_ｘは以下のように表される。

G _x is calculated based on the vehicle model of vehicle V. The vehicle model is represented by, for example, the following equation of state.

Here, X = [x v] ^T. In addition, x is the position of the vehicle, v is the vehicle speed, λ is the air resistance coefficient, S is the vehicle front projection area, μ is the rolling resistance coefficient, g is the gravitational acceleration, θ is the slope of the road, and u (t) is the control input. is there.
Based on the above equation of state, the acceleration / deceleration speed G _{x in the} front-rear direction is expressed as follows.

G _y is represented by the curvature and the vehicle speed corresponding to the target value. Specifically, assuming that the radius of curvature (that is, the turning radius) of the road at the target setting point is R, _Gy is represented by _{v t} ^{2 / R.}

The target value determining unit 123 determines the target value based on the evaluation function in which the first weighting coefficient and the second weighting coefficient are determined based on the desired characteristics notified from the receiving unit 121. When the first weighting coefficient becomes large, priority is given to reducing the combined vector of the front-rear acceleration / deceleration and the lateral acceleration / deceleration. When the second weighting coefficient becomes large, it is prioritized to reduce the difference from the speed set by the ACC function. The target value determining unit 123 increases the first weighting factor when the driver gives priority to riding comfort, and gives priority to following the set vehicle speed (for example, giving priority to following the preceding vehicle). 2 Increase the weighting factor.

[Effect of vehicle control device 1]
As described above, the target value determining unit 123 determines the control value that affects the vehicle speed so as to minimize the evaluation function including the term of the combined vector of the acceleration / deceleration in the front-rear direction and the acceleration / deceleration in the lateral direction. By using such an evaluation function, the target value determining unit 123 starts deceleration before the vehicle V reaches the curved portion, and the deceleration in the front-rear direction does not occur at the position where the curvature is maximized. , It is possible to control the speed according to the driver's feeling.

[First modification]
The above evaluation function included the first term including the composite vector of acceleration / deceleration and the second term including the difference between the target value of the vehicle speed and the set speed, but the evaluation function contains other terms. It may be included. For example, the evaluation function may include a term related to fuel consumption. In this case as well, the target value determining unit 123 determines the target value so that the evaluation function becomes the minimum value, so that the target value determining unit 123 can optimize the balance between fuel consumption, riding comfort, and vehicle speed. it can.

The target value determination unit 123 may determine the weighting coefficient of the item related to fuel consumption based on the desired characteristic notified from the reception unit 121. For example, when the desired characteristic indicates that the driver attaches great importance to fuel efficiency, the target value determining unit 123 increases the weighting coefficient of the item related to fuel efficiency to drive the vehicle V in a state of good fuel efficiency. Becomes possible.

[Second modification]
The vehicle V may be a commercial vehicle having a mounting portion. In this case, the target value determining unit 123 may determine the constraint condition based on the state of the load mounted on the mounting unit. The target value determining unit 123 is based on the center of gravity of the load or the weight of the load so that it is difficult to roll over even when the center of gravity of the load is high or the weight of the load is heavy. To determine. By operating the target value determining unit 123 in this way, it is possible to reduce the risk of the commercial vehicle rolling over while maintaining a good ride quality on a curve.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes can be made within the scope of the gist thereof. is there. For example, all or a part of the device can be functionally or physically distributed / integrated in any unit. Also included in the embodiments of the present invention are new embodiments resulting from any combination of the plurality of embodiments. The effect of the new embodiment produced by the combination also has the effect of the original embodiment.

1 Vehicle control device 2 Operation unit 3 Control target 11 Storage unit 12 Control unit 121 Reception unit 122 Curvature identification unit 123 Target value determination unit

Claims (8)

A curvature specifying part that specifies the curvature of a predetermined point on the road in the direction of travel of the vehicle,
A predetermined constraint condition is the lateral acceleration / deceleration, which is the lateral acceleration / deceleration of the vehicle in the evaluation section in which the vehicle travels for a finite time from the time when the vehicle passes the predetermined point, which is predicted based on the curvature. The evaluation function including the first term based on the composite vector obtained by synthesizing the front-rear acceleration / deceleration and the lateral acceleration / deceleration, which is the predicted value of the acceleration / deceleration of the vehicle in the front-rear direction in the evaluation section, becomes the minimum value. As described above, the target value determining unit for determining the target value of the control value for controlling the vehicle, and the target value determining unit.
Vehicle control device with. In the evaluation function, when the control value at time t is u (t), the front-rear acceleration / deceleration is

X is the position of the vehicle, v is the vehicle speed, λ is the air resistance coefficient, S is the front projection area of the vehicle, μ is the rolling resistance coefficient, g is the gravitational acceleration, and θ is the slope of the road.
The vehicle control device according to claim 1. In the evaluation function, the lateral acceleration / deceleration is represented by the curvature and the vehicle speed corresponding to the target value.
The vehicle control device according to claim 1 or 2. The evaluation function further includes a second term based on the difference between the preset speed set in the evaluation section and the target speed corresponding to the target value.
The target value determining unit determines the target value so that the evaluation function becomes the minimum value.
The vehicle control device according to any one of claims 1 to 3. It also has a reception unit that receives desired characteristics that are the driving characteristics desired by the occupants of the vehicle.
The first term in the evaluation function includes a first weighting factor, and the second term includes a second weighting factor.
The target value determining unit determines the target value based on the evaluation function in which the first weighting coefficient and the second weighting coefficient are determined based on the desired characteristic.
The vehicle control device according to claim 4. The evaluation function further includes a term corresponding to fuel consumption.
The target value determining unit determines the target value so that the evaluation function becomes the minimum value.
The vehicle control device according to any one of claims 1 to 5. The vehicle has a mounting part and
The target value determining unit determines the constraint condition based on the state of the load mounted on the mounting unit.
The vehicle control device according to any one of claims 1 to 6. Computer runs,
Steps to identify the curvature of a given point on the road in the direction of travel of the vehicle,
A predetermined constraint condition is the lateral acceleration / deceleration, which is the lateral acceleration / deceleration of the vehicle in the evaluation section in which the vehicle travels for a finite time from the time when the vehicle passes the predetermined point, which is predicted based on the curvature. The evaluation function including the first term based on the composite vector obtained by synthesizing the front-rear acceleration / deceleration and the lateral acceleration / deceleration, which is the predicted value of the acceleration / deceleration of the vehicle in the front-rear direction in the evaluation section, becomes the minimum value. As described above, the step of determining the target value of the control value for controlling the vehicle, and
Vehicle control method having.

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