JP2023160640A - Vehicle speed control method and vehicle speed control device - Google Patents

Abstract

To prevent behavior of an own vehicle traveling on a target travel trajectory from getting unstable due to frequency of a yaw rate.SOLUTION: In a vehicle speed control method, a target travel trajectory of an own vehicle is set; resonance frequency of a yaw rate of the own vehicle is calculated on the basis of a motion characteristic value of the own vehicle; and a target vehicle speed when the own vehicle travels on the target travel trajectory is set so that frequency of the yaw rate while the own vehicle travels on the target travel trajectory becomes less than the resonance frequency (S2, S3, S17 and S18). Also, in the vehicle speed control method, a vehicle speed of the own vehicle is controlled on the basis of the target vehicle speed (S4).SELECTED DRAWING: Figure 9

Description

The present invention relates to a vehicle speed control method and a vehicle speed control device.

Patent Document 1 describes a technique for setting a target speed so that turning acceleration does not exceed a road surface friction coefficient while an autonomous vehicle is automatically traveling on a target travel trajectory.

Japanese Patent Application Publication No. 2017-121874

Since the yaw motion of the vehicle has a resonant frequency, when the frequency of the yaw rate of the vehicle approaches the resonant frequency, the vehicle behavior may become unstable.
An object of the present invention is to suppress the behavior of a host vehicle traveling on a target travel trajectory from becoming unstable due to the frequency of the yaw rate.

In the vehicle speed control method according to one aspect of the present invention, a target travel trajectory of the host vehicle is set, a resonance frequency of the yaw rate of the host vehicle is calculated based on the motion characteristic values of the host vehicle, and the host vehicle travels on the target travel trajectory. The target vehicle speed is set so that the frequency of the yaw rate of the own vehicle while traveling on the target travel trajectory is less than the resonance frequency, and the vehicle speed of the own vehicle is controlled based on the target vehicle speed.

According to the present invention, it is possible to suppress the behavior of the host vehicle traveling on the target travel trajectory from becoming unstable due to the frequency of the yaw rate.

1 is a schematic configuration diagram of a driving support device according to an embodiment. It is an explanatory view of an example of architecture of automatic driving control by a driving support device of an embodiment. It is a block diagram showing an example of the functional composition of the automatic driving control part of the driving support device of an embodiment. FIG. 2 is a block diagram of an example of a functional configuration of a vehicle control section shown in FIG. 1. FIG. (a) is an explanatory diagram of an example of a first vehicle speed profile, (b) is an explanatory diagram of an example of a second vehicle speed profile, and (c) is an explanatory diagram of an example of a third vehicle speed profile. FIG. 5 is a block diagram of an example of a functional configuration of a backward calculation unit shown in FIG. 4. FIG. 5 is a block diagram of an example of a functional configuration of a forward calculation section shown in FIG. 4. FIG. It is a flow chart of an example of the vehicle speed control method of an embodiment. 9 is a flowchart of an example of the process of step S2 in FIG. 8.

Embodiments of the present invention will be described below with reference to the drawings. Note that each drawing is schematic and may differ from the actual drawing. In addition, the embodiments of the present invention shown below illustrate devices and methods for embodying the technical idea of the present invention. is not limited to the following: The technical idea of the present invention can be modified in various ways within the technical scope defined by the claims.

Please refer to FIG. The host vehicle 1 is a front-wheel steering vehicle capable of steering the front right wheel 2FR and the front left wheel 2FL, or is a four-wheel steering vehicle capable of steering the front right wheel 2FR, the front left wheel 2FL, the rear right wheel 2RR, and the rear left wheel 2RL. It is. Hereinafter, the right front wheel 2FR and left front wheel 2FL will be collectively referred to as "front wheel 2F", the right rear wheel 2RR and left rear wheel 2RL will be collectively referred to as "rear wheel 2R", and the front wheel 2F and rear wheel 2R will be referred to as "front wheel 2F". They may be collectively referred to as "wheels 2."
The own vehicle 1 includes a driving support device 10 that provides driving support for the own vehicle 1. Driving support by the driving support device 10 includes automatic driving control that automatically drives the own vehicle 1 without the driver's involvement based on the driving environment around the own vehicle 1, and driving of the own vehicle 1 by the driver. It may include driving support control to support the driver.
The driving support control includes driving control that controls at least one of the steering device, drive device, and braking device of the own vehicle 1, such as automatic steering, automatic brakes, constant speed driving control, lane keeping control, and merging support control. That's fine.

The driving support device 10 includes an object sensor 11, a vehicle sensor 12, a positioning device 13, a map database (map DB) 14, a navigation device 15, a controller 17, and an actuator 18.
The object sensor 11 detects objects around the own vehicle. The object sensor 11 is one of a plurality of different types that detect objects around the own vehicle 1, such as a laser radar, a millimeter wave radar, a camera, and a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging) mounted on the own vehicle 1. Equipped with an object detection sensor.

The vehicle sensor 12 is mounted on the own vehicle 1 and detects various information (vehicle signals) obtained from the own vehicle 1. The vehicle sensor 12 includes, for example, a vehicle speed sensor that detects the vehicle speed (traveling speed) V of the own vehicle 1, a wheel sensor that detects the rotational speed and amount of rotation of the wheel 2, and an acceleration (deceleration) of the own vehicle 1 in three axial directions. a 3-axis acceleration sensor (G sensor) that detects the steering angle (including It includes a gyro sensor, a yaw rate sensor that detects the yaw rate, an accelerator sensor that detects the accelerator opening of the own vehicle 1, and a brake sensor that detects the amount of brake operation by the driver.

The positioning device 13 includes a global positioning system (GNSS) receiver, and measures the current position of the own vehicle 1 by receiving radio waves from a plurality of navigation satellites. The GNSS receiver may be, for example, a Global Positioning System (GPS) receiver. The positioning device 13 may be, for example, an inertial navigation device.
The map database 14 may store high-precision map data (hereinafter simply referred to as "high-precision map") suitable as a map for automatic driving. The high-precision map is map data with higher precision than navigation map data (hereinafter simply referred to as "navigation map"), and includes information on a lane-by-lane basis that is more detailed than information on a road-by-road basis.
The navigation device 15 recognizes the current position of the host vehicle 1 using the positioning device 13 and the like. The navigation device 15 acquires road information and traffic information around the own vehicle 1 based on the recognized current position, and outputs it to the controller 17. Furthermore, the navigation device 15 provides route guidance to the occupants, and also provides road information and traffic information.

The controller 17 is an electronic control unit (ECU) that includes a processor and peripheral components such as a storage device, and performs driving support control of the own vehicle 1. The processor may be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit).
The storage device may include a semiconductor storage device, a magnetic storage device, an optical storage device, or the like. The storage device may include memory such as a register, a cache memory, a ROM (Read Only Memory) used as a main storage device, and a RAM (Random Access Memory).
When the processor of the controller 17 executes a computer program stored in the storage device, the controller 17 functions as an automatic driving control section 20, an input arbitration section 21, and a vehicle control section 22. These functions will be described later.

Note that the controller 17 may be formed of dedicated hardware for executing each information process described below.
For example, the controller may include a functional logic circuit set in a general-purpose semiconductor integrated circuit. For example, the controller may include a programmable logic device (PLD) such as a field-programmable gate array (FPGA).

Actuator 18 operates the steering device, drive device, and braking device of host vehicle 1 in response to a control signal from controller 17 to generate vehicle behavior of host vehicle 1 . The actuator 18 includes a steering actuator, an accelerator opening actuator, and a brake control actuator.
When the host vehicle 1 is a front wheel steered vehicle, the steering actuator controls the front wheel steering angle _δF , which is the steering angle of the front wheels 2F. When the host vehicle 1 is a four-wheel steered vehicle, the steering actuator controls a rear wheel steering angle δ _R , which is the steering angle of the rear wheels 2R, in addition to the front wheel steering angle δ _F.

The steering actuator may be, for example, a steering assist motor that provides steering assist force in an electric power steering system, and steers the wheels 2 in a steering-by-wire system in which the steering wheel and the wheels 2 are mechanically separated. It may also be a steering motor.
The accelerator opening actuator controls the accelerator opening of a drive device (for example, an engine or an electric motor) that is a power source that generates the driving force of the host vehicle 1 . The brake control actuator controls the braking operation of the braking device of the own vehicle 1.
The combination of the driving device, the braking device, the controller 17, and the actuator 18 is an example of the "speed control device" described in the claims.

Next, an example of driving support control by the driving support device 10 of the embodiment will be explained. FIG. 2 shows an example of the architecture of automatic driving control by a driving support device. Automatic driving control includes an automatic driving layer (AD layer) 30, an arbitration section (Arbitration) 31, a reference model section (Reference Model) 32, a body motion control section (Body Motion Control) 33, and a wheel behavior control section ( Wheel Motion Control) 34 and the actuator 18 described above.
The automatic driving layer 30 sets the destination of the own vehicle 1 and sets the driving route from the current position of the own vehicle 1 to the destination. Note that the destination may be the final destination set by the driver, or a point a predetermined distance ahead of the current position of the host vehicle 1 (for example, a point on the lane in which the host vehicle is traveling). (or the center position of the lane a predetermined distance ahead).
The automatic driving layer 30 determines the target traveling trajectory of the own vehicle 1 traveling on the driving route, that is, the traveling trajectory on the road from the current position of the own vehicle 1 to the destination, according to the automatic driving instruction input from the automatic driving layer 30. Generate as input (AD input).

The arbitration unit 31 arbitrates between manual driving input (MD input), which is the steering wheel, accelerator, and brake operation input by the driver, and the automatic driving input from the automatic driving layer 30, and determines the vehicle movement that the own vehicle 1 should perform. Set.
The reference model unit 32 uses parameters of a vehicle motion model (for example, yaw moment of inertia, cornering of the wheels 2, stiffness, etc.).
The vehicle behavior control unit 33 controls vehicle behavior (for example, vehicle speed, acceleration/deceleration, yaw rate, yaw angular acceleration) to realize the vehicle motion set by the arbitration unit 31 based on the vehicle motion model set by the reference model unit 32. , yaw moment, etc.).

The wheel behavior control unit 34 calculates the control amount (steering angle, braking amount, drive amount, etc.) of the wheels 2 in order to cause the own vehicle 1 to generate the vehicle body behavior calculated by the vehicle body behavior control unit 33, and controls the amount of control by the actuator 18. Control wheel behavior.
For example, the function of the automatic driving layer 30 is handled by the automatic driving control unit 20 shown in FIG. The functions of 34 may be performed by the vehicle control unit 22.

Next, an example of the functional configuration of the automatic operation control unit 20 will be described with reference to FIG. 3. The automatic driving control unit 20 includes a localization unit 40, a destination setting unit 41, a route planning unit 42, a decision making unit 43, and a driving zone planning unit. (Drive Zone Planning) 44 and a trajectory generation unit (Trajectory) 45.

The localization unit 40 recognizes the surrounding environment of the own vehicle 1 based on the detection signal of the object sensor 11. The localization unit 40 determines the current position of the own vehicle 1 on the high-precision map by map matching between the recognition result and the high-precision map in the map database 14 .
Furthermore, a local model 47 that is a model of the surrounding environment of the own vehicle 1 is generated based on the recognition result of the surrounding environment. Furthermore, a world model (World Model) 46 is generated by fusing the local model 47, the high-precision map, and the road information and traffic information of the navigation device 15.

The destination setting unit 41 sets the destination of the own vehicle 1 based on the driver's operation input via the navigation device 15.
The route planning unit 42 calculates a planned travel route from the current position to the destination based on the road information from the navigation device 15. Note that the planned travel route is not limited to this, and may be, for example, a planned route from the current position to a predetermined distance ahead of the host vehicle. Alternatively, without using the road information from the navigation device 15, the route ahead of the vehicle may be captured by a camera or the like, and the planned route may be a predetermined distance ahead of the vehicle detected from the captured image.
The action determining unit 43 determines a driving action plan for the own vehicle 1 to be executed by the driving support device 10 based on the recognition result of the surrounding environment, the current position of the own vehicle 1, the world model 46, and the planned travel route. do.

Driving actions include, for example, stopping, pausing, driving speed, deceleration, acceleration, changing course, turning right, turning left, going straight, changing lanes in merging sections or in multiple lanes, maintaining lane, overtaking, and approaching obstacles. This includes actions such as responding to
The action determining unit 43 generates a driving action plan for the own vehicle 1 based on the current position and orientation of the own vehicle 1, the surrounding environment of the own vehicle 1, and the world model 46.

The driving zone planning unit 44 calculates a driving zone, which is a region in which the own vehicle 1 can travel, based on the generated driving action plan, the motion characteristics of the own vehicle 1, and the local model 47.
The trajectory generation unit 45 generates a target travel trajectory for the host vehicle 1 so that the host vehicle 1 travels within the driving zone calculated by the driving zone planning unit 44.

Please refer to FIG. The input arbitration unit 21 arbitrates between the automatic driving input of the target travel trajectory set by the automatic driving control unit 20 and the manual driving input by the driver, and sets the vehicle movement that the own vehicle 1 should perform.
The vehicle control unit 22 controls the behavior of the own vehicle 1 so as to realize the vehicle motion set by the input arbitration unit 21.

Next, vehicle speed control by the vehicle control section 22 will be explained. In order for the host vehicle 1 to travel while following the target travel trajectory, it is necessary to set the target vehicle speed so that the frictional force of the wheels 2 does not exceed the friction limit due to the lateral acceleration at the center of gravity of the host vehicle 1.
Furthermore, since the magnitude of the friction limit of the front wheel 2F and the friction limit of the rear wheel 2R changes depending on load fluctuations accompanying acceleration and deceleration of the own vehicle 1, the friction force generated on the front wheel 2F and the rear wheel 2R is It is necessary to set the target vehicle speed so as not to exceed the friction limit of the rear wheels 2R.
For example, in the case of a driving scene in which the vehicle turns while decelerating, a large braking force is generated at the front wheels 2F, and a large lateral force is generated at the front wheels 2F to cause the vehicle to turn. Therefore, the frictional force of the front wheels 2F tends to become saturated, which may lead to a decrease in the ability to follow the target travel trajectory.

Therefore, the vehicle control unit 22 determines that the resultant force of the braking force and lateral force of each of the front wheels 2F and rear wheels 2R, and the resultant force of the driving force and lateral force of each of the front wheels 2F and rear wheels 2R, exceed the friction limit. Limit the target vehicle speed so that it does not exceed it.
Thereby, the target vehicle speed can be set so that the friction force of the front wheels 2F and the friction force of the rear wheels 2R do not exceed the friction limit, and the ability to follow the target travel trajectory is improved.

Further, as described above, since the yaw motion of the vehicle has a resonance frequency, when the frequency of the yaw rate of the host vehicle 1 approaches the resonance frequency, there is a possibility that the vehicle behavior becomes unstable.
Here, the yaw rate γ when turning at a certain point on the target travel trajectory can be expressed as γ=ρV, where V is the vehicle speed of the host vehicle 1 and ρ is the turning curvature. Therefore, the amount of change in yaw rate γ over time γ'=(dρ/dt)V+ρ(dV/dt) is the acceleration/deceleration of the host vehicle 1 in the traveling direction (that is, longitudinal direction), Ax, and the change in turning curvature per unit distance. When ρ' is assumed, it can be expressed as γ'=ρ'V ² +ρAx.
That is, the frequency of the yaw rate changes not only depending on the amount of change in curvature but also depending on the acceleration/deceleration Ax in the traveling direction. Therefore, vehicle behavior may become unstable not only in driving scenes where the curvature changes are large, such as at the entrance to a curved road or at an S-curve, but also in scenes where strong acceleration or deceleration occurs during turning even if the curvature change is small. There is.
Therefore, in addition to the above-mentioned restriction based on the friction limit, the vehicle control unit 22 restricts the target vehicle speed so that the frequency of the yaw rate of the host vehicle 1 becomes less than the resonance frequency.

FIG. 4 is a block diagram of an example of the functional configuration of the vehicle control section 22 shown in FIG. 1. The vehicle control section 22 includes a geometric calculation section 50, a backward calculation section 51, and a forward calculation section 52.
The geometry calculation unit 50 calculates the turning curvature ρ of the target travel trajectory generated by the trajectory generation unit 45 in _FIG . Based on the maximum yaw rate setting value γ _Max , the lateral acceleration of the center of gravity of the own vehicle 1 does not exceed the maximum lateral acceleration setting value A _yMax , and the yaw rate of the own vehicle 1 does not exceed the maximum yaw rate setting value γ _Max . Next, a first vehicle speed profile V _in , which is a profile of the target vehicle speed of the host vehicle, is calculated.
For example, if the turning curvature at a point i on the target traveling trajectory is ρ _i , the geometric calculation unit 50 may set the target vehicle speed V _i at the point i based on the following equation (1).

FIG. 5(a) shows an example of the first vehicle speed profile V _in . In the figure, the horizontal axis represents the travel distance from the current position of the host vehicle 1 to each point in front of the host vehicle on the target travel trajectory, and the vertical axis represents the target vehicle speed at each point.
Note that the leftmost point on the paper of the horizontal axis in FIG. 5(a) is the current position of the own vehicle 1, and the rightmost point is the point on the target travel trajectory where the first vehicle speed profile V _in was generated. This is the farthest point from the host vehicle 1 (hereinafter referred to as the "farthest point"). The same applies to FIGS. 5(b) and 5(c).

See FIG. 4. The backward calculation unit 51 controls each of the front wheels 2F and the rear wheels 2R at each point on the target travel trajectory based on the respective loads applied to the front wheels 2F and the rear wheels 2R according to the deceleration of the host vehicle 1. Calculate the maximum backward speed so that the resultant force of power and lateral force does not exceed the friction limit. Further, the backward calculation unit 51 calculates the maximum backward speed based on the vehicle speed, the turning curvature, and the change in the curvature so that the frequency of the yaw rate of the own vehicle 1 is less than the resonance frequency.
The backward calculation unit 51 sets the second vehicle speed profile _VB by limiting the first vehicle speed profile V _in by the maximum backward speed.
FIG. 5(b) shows an example of the second vehicle speed profile _VB .

Here, if it is not possible to decelerate from the target vehicle speed V in (i) of the first vehicle speed _profile V _in at point i to the target vehicle speed V _in (i+1) at the forward point (i+1) due to the restriction due to the friction limit, the vehicle speed will decrease to the first vehicle speed. The vehicle speed profile V _in will be exceeded and the vehicle will not be able to travel along the target travel trajectory.
Therefore, the backward calculation unit 51 limits the target vehicle speed V _in (i) at the point of interest i based on the target vehicle speed V _in (i+1) at the point (i+1) ahead of the point of interest i.
Specifically, based on the target vehicle speed V _in (i+1) and the turning curvature ρ (i+1) at the point (i+1), the maximum deceleration A _x (i+1) allowed for the host vehicle 1 at the point (i+1) is determined. calculate.
Then, based on the respective loads applied to the front wheels 2F and rear wheels 2R according to the maximum deceleration A _x (i+1) at the point (i+1), the braking force and lateral force of the front wheels 2F and rear wheels 2R are calculated at the point of interest i. Assuming that the resultant force does not exceed the friction limit, calculate the maximum speed as the backward maximum speed. At this time, the frequency of the yaw rate of the host vehicle 1 becomes less than the resonance frequency based on the target vehicle speed V _in (i+1) at point (i+1), the turning curvature ρ(i+1), and the curvature change ρ'(i+1). Calculate the backward maximum speed as follows. Then, the target vehicle speed of the first vehicle speed profile V _in at the point of interest i is limited by the backward maximum speed. This calculation is repeated while moving the point of interest i backward one by one from the farthest point toward the current position of the host vehicle 1.

See FIG. 4. The forward calculation unit 52 calculates the driving force of each of the front wheels 2F and the rear wheels 2R based on the respective loads applied to the front wheels 2F and the rear wheels 2R according to the acceleration of the host vehicle 1 at each point on the target traveling trajectory. Calculate the maximum forward speed so that the resultant force with the lateral force does not exceed the friction limit. The forward calculation unit 52 calculates the maximum forward speed based on the vehicle speed, the turning curvature, and the change in the curvature so that the frequency of the yaw rate of the host vehicle 1 is less than the resonance frequency.
The forward calculation unit 52 sets the third vehicle speed profile V _out by limiting the second vehicle speed profile V _B by the maximum forward speed.
The vehicle control unit 22 controls the speed of the host vehicle 1 by driving the accelerator opening actuator and the brake control actuator of the actuator 18 based on the third vehicle speed profile V _out .

The forward calculation unit 52, contrary to the backward calculation unit 51, performs calculation while moving the attention point i forward one by one from the current position of the host vehicle 1 toward the farthest point. That is, based on the target vehicle speed V _in (i-1) and the turning curvature ρ (i-1) at the point (i-1) one place behind the point of interest i, the own vehicle 1 at the point (i-1) The maximum acceleration A _x (i-1) allowed for is calculated.
Then, based on the respective loads applied to the front wheels 2F and rear wheels 2R according to the maximum acceleration A _x (i-1) at the point (i-1), the driving force of the front wheels 2F and rear wheels 2R at the point of interest is calculated. The maximum speed at which the resultant force with the lateral force does not exceed the friction limit is calculated as the maximum forward speed. At this time, the yaw rate of the own vehicle 1 is determined based on the target vehicle speed V _in (i-1) at the point (i-1), the turning curvature ρ (i-1), and the curvature change ρ' (i-1). Calculate the maximum forward speed so that the frequency of is less than the resonance frequency. Then, the target vehicle speed of the second vehicle speed profile _VB at the point of interest i is limited by the maximum forward speed. This calculation is repeated while moving the point of interest i forward one by one from the current position of the host vehicle 1 toward the farthest point.

In the examples shown in FIGS. 4 and 5(a) to 5(c), the backward calculation unit 51 sets the second vehicle speed profile V _B by limiting the first vehicle speed profile V _in , and performs the forward calculation. Although the unit 52 sets the third vehicle speed profile V _out by limiting the second vehicle speed profile V _B , instead of this, the forward calculation unit 52 limits the first vehicle speed profile V _in and sets the second vehicle speed profile V out. _VB may be set, and the backward calculation unit 51 may limit the second vehicle speed profile _VB to set the third vehicle speed profile _Vout .

Next, details of the backward calculation section 51 and the forward calculation section 52 will be explained. FIG. 6 is a block diagram of an example of the functional configuration of the backward calculation section 51.
The backward calculation unit 51 sets a point one point behind the farthest point as the first point of interest i, and sequentially moves the point of interest backward one by one to the current position of the own vehicle 1. Maximum deceleration A _x (i) and target vehicle speed V _Tar (i) at i are calculated.
The backward calculation section 51 includes a maximum speed calculation section 51a, selectors 51b, 51k, and 51n, a load calculation section 51c, a target lateral force calculation section 51d, a maximum lateral force calculation section 51e, and a target longitudinal force calculation section 51h. , a maximum longitudinal force calculation section 51i, a first maximum acceleration/deceleration calculation section 51j, and a second maximum acceleration/deceleration calculation section 51m.

式（２）のΔｓ（ｉ）は、注目地点ｉと地点（ｉ＋１）との間の距離である。 In the calculation at the first point of interest i, the maximum speed calculation unit 51a sets the first vehicle speed profile V in at the farthest point as the target vehicle speed V _Tar (i+1) of the point (i+1) one point ahead of the point of interest _i . A target vehicle speed is set, and the maximum deceleration setting value A _xMax , which is preset as the maximum allowable deceleration, is set as the maximum deceleration A _x (i+1) at the point (i+1).
In calculations at the second and subsequent points of interest i, the target vehicle speed V _Tar (i+1) and maximum deceleration A _x (i+1) calculated at the previous point of interest (ie, point (i+1)) are input.
The maximum speed calculation unit 51a sets the speed limit value of the following equation (2) according to the target vehicle speed V _Tar (i+1) and the maximum deceleration A _x (i+1) at the previous point (i+1).

Δs(i) in equation (2) is the distance between the point of interest i and the point (i+1).

バックワード演算部５１は、目標車速Ｖ_Ｔａｒ（ｉ）を注目地点ｉにおける第２車速プロファイルＶ_Ｂの目標車速Ｖ_Ｂ（ｉ）として出力する。 The selector 51b sets the target vehicle speed V _Tar (i) at the point of interest i by limiting the target vehicle speed V _in (i) of the first vehicle speed profile V _in at the point of interest i according to the following equation (3).

The backward calculation unit 51 outputs the target vehicle speed V _Tar (i) as the target vehicle speed V _B (i) of the second vehicle speed profile V _B at the point of interest i.

上式（４）及び（５）におけるｍは自車両１の質量であり、ｇは重力加速度であり、ｌはホイールベース長であり、ｌ_Ｆは車両重心から前輪軸までの長さであり、ｌ_Ｒは車両重心から後輪軸までの長さあり、κ_ｐは、車両諸元に応じて定まる荷重パラメータであり、左辺第１項及び第２項は、それぞれ静荷重と動荷重を表す。 The load calculation unit 51c calculates the pitch motion of the vehicle body of the own vehicle 1 according to the maximum deceleration A _x (i+1) at the point (i+1) one point ahead, based on the following equations (4) and (5). A front wheel load Fz _F (i), which is the load on the front wheel 2F, and a rear wheel load Fz _R (i), which is the load on the rear wheel 2R, are calculated.

In the above formulas (4) and (5), m is the mass of the host vehicle 1, g is the gravitational acceleration, l is the wheelbase length, _lF is the length from the vehicle center of gravity to the front wheel axle, l _R is the length from the vehicle center of gravity to the rear wheel axis, κ _p is a load parameter determined according to vehicle specifications, and the first and second terms on the left side represent the static load and dynamic load, respectively.

上式（６）及び（７）におけるＩｚは自車両１の慣性モーメントであり、γ'（ｉ）は目標車速Ｖ_Ｔａｒ（ｉ）と旋回曲率ρ（ｉ）とに応じたヨー角加速度である。 The target lateral force calculation unit 51d calculates the front wheel 2F according to the target vehicle speed V _Tar (i) at the point of interest and the turning curvature ρ(i) of the target traveling trajectory based on the following equations (6) and (7). A front wheel target lateral force Fy _ReqF (i), which is the target lateral force to be generated at the rear wheel 2R, and a rear wheel target lateral force Fy _ReqR (i), which is the target lateral force to be generated at the rear wheel 2R, are calculated.

Iz in the above equations (6) and (7) is the moment of inertia of the host vehicle 1, and γ'(i) is the yaw angular acceleration according to the target vehicle speed V _Tar (i) and the turning curvature ρ(i). .

上式（８）及び（９）におけるμは路面の摩擦係数である。 The maximum lateral force calculation unit 51e calculates the front wheel load Fz _F (i), the rear wheel load Fz _R (i), the target vehicle speed V _Tar (i), and the maximum Based on the lateral acceleration setting value A _yMax and the maximum yaw rate setting value γ _Max preset as the maximum allowable yaw rate, the front wheel maximum lateral force Fy _MaxF (i) is the maximum lateral force that may be generated in the front wheel 2F. , the rear wheel maximum lateral force Fy _MaxR (i), which is the maximum lateral force that may be generated in the rear wheel 2R, is calculated.

μ in the above equations (8) and (9) is the coefficient of friction of the road surface.

上式（１０）における目標横力Ｆｙ_Ｒｅｑは、自車両１の車体の重心の目標横力であり、Ｆｙ_Ｒｅｑ＝Ｆｙ_ＲｅｑＦ（ｉ）＋Ｆｙ_ＲｅｑＲ（ｉ）である。同様に、最大横力Ｆｙ_Ｍａｘは、自車両１の車体の重心に発生させてよい最大横力であり、Ｆｙ_Ｍａｘ＝Ｆｙ_ＭａｘＦ（ｉ）＋Ｆｙ_ＭａｘＲ（ｉ）である。
上式（８）及び（９）に示すように、Ｆｙ_ＭａｘＦ（ｉ）、Ｆｙ_ＭａｘＲ（ｉ）は、前輪２Ｆ及び後輪２Ｒの摩擦円の大きさμＦｘ_Ｆ（ｉ）、μＦｘ_Ｒ（ｉ）で制限される。
したがって上式（１０）は、前輪荷重Ｆｚ_Ｆ（ｉ）及び後輪荷重Ｆｚ_Ｒ（ｉ）に応じた車体全体の摩擦円と、前輪目標横力Ｆｙ_ＲｅｑＦ（ｉ）及び後輪目標横力Ｆｙ_ＲｅｑＲ（ｉ）と、により最大減速度設定値Ａ_ｘＭａｘに対応する縦力ｍＡ_ｘＭａｘを制限することによって目標縦力Ｆｘ_Ｒｅｑ（ｉ）を求めている。 The target longitudinal force calculation unit 51h calculates the maximum deceleration setting value Ax _Max , the front wheel target lateral force Fy _ReqF (i), the rear wheel target lateral force Fy ReqR (i), and the front wheel target lateral force Fy _ReqR (i) based on the following equation (10). A target longitudinal force Fx _Req (i) to be generated in the own vehicle 1 _is calculated according to the maximum lateral force Fy MaxF (i) and the maximum rear wheel lateral force Fy _MaxR (i).

The target lateral force Fy _Req in the above formula (10) is the target lateral force of the center of gravity of the body of the own vehicle 1, and is Fy _Req = Fy _ReqF (i) + Fy _ReqR (i). Similarly, the maximum lateral force Fy _Max is the maximum lateral force that may be generated at the center of gravity of the vehicle body of the host vehicle 1, and is Fy _Max =Fy _MaxF (i) + Fy _MaxR (i).
As shown in the above formulas (8) and (9), Fy _MaxF (i) and Fy _MaxR (i) are the sizes of the friction circles of the front wheel 2F and the rear wheel 2R μFx _F (i), μFx _R (i) limited by.
Therefore, the above formula (10) calculates the friction circle of the entire vehicle body according to the front wheel load Fz _F (i) and the rear wheel load Fz _R (i), the front wheel target lateral force Fy _ReqF (i) and the rear wheel target lateral force Fy The target longitudinal force Fx _Req (i) is obtained by limiting the longitudinal force mA _xMax corresponding to the maximum deceleration setting value A _xMax by _ReqR (i).

The target longitudinal force calculation unit 51h sets the target longitudinal force Fx _Req (i) to the brake distribution ratio κ _F :(1−κ _F ) of the front wheels 2F and the rear wheels 2R based on the following equations (11) and (12). By distributing the target longitudinal force Fx ReqF (i), which is the target longitudinal force to be generated on the front wheels 2F, and the target longitudinal force Fx _ReqR (i), which is the target lateral force to be generated on the rear wheels _2R , ) are calculated respectively.

The maximum longitudinal force calculation unit 51i calculates the respective friction circles of the front wheel 2F and the rear wheel 2R according to the front wheel load Fz _F (i) and the rear wheel load Fz _R (i), and the front wheel maximum lateral force Fy _MaxF (i). , based on the rear wheel maximum lateral force Fy _MaxR (i), the front wheel maximum longitudinal force Fx _MaxF (i) which is the maximum longitudinal force that can be generated on the front wheel 2F, and the maximum longitudinal force that can be generated on the rear wheel 2R. A certain rear wheel maximum longitudinal force Fx _MaxR (i) is calculated.
Specifically, the maximum longitudinal force calculation unit 51i calculates the front wheel maximum longitudinal force Fx _MaxF (i) and the rear wheel maximum longitudinal force Fx _MaxR (i) based on the following equations (13) and (14).

第１最大加減速度演算部５１ｊは、最大縦力Ｆｘ_Ｍａｘ（ｉ）により生じる減速度（Ｆｘ_Ｍａｘ（ｉ）／ｍ）を第１最大減速度Ａｘ１（ｉ）としてセレクタ５１ｋに出力する。
セレクタ５１ｋは、第１最大減速度Ａｘ１（ｉ）と最大減速度設定値Ａ_ｘＭａｘのうちいずれか小さい方を、最大減速度候補Ａｘｃとしてセレクタ５１ｎへ出力する。 The first maximum acceleration/deceleration calculation unit 51j calculates the smaller value min (Fx _ReqF (i), Fx _MaxF (i)) of the front wheel target longitudinal force Fx _ReqF (i) and the front wheel maximum longitudinal force Fx _MaxF (i), and the rear wheel target longitudinal force Fx ReqF (i). The smaller value min (Fx _ReqR (i), Fx _MaxR (i)) of the wheel target longitudinal force Fx _ReqR (i) and the rear wheel maximum longitudinal force Fx _MaxR (i) is the ratio of the target lateral force to the maximum lateral force. Fy _ReqF (i) / Fy _MaxF (i) and Fy _ReqR (i) / Fy _MaxR (i) are respectively limited, and the sum of these is determined as the maximum longitudinal value at which the friction force of front wheel 2F and rear wheel 2R does not exceed the friction limit. The force is calculated as Fx _Max (i) (the following equation (15)).

The first maximum acceleration/deceleration calculation unit 51j outputs the deceleration (Fx _Max (i)/m) caused by the maximum longitudinal force Fx _Max (i) to the selector 51k as the first maximum deceleration Ax1(i).
The selector 51k outputs the smaller of the first maximum deceleration Ax1(i) and the maximum deceleration setting value _AxMax to the selector 51n as the maximum deceleration candidate Axc.

式（１６）における自車両１の運動特性値である、Ｃ_Ｆ及びＣ_Ｒはそれぞれ前輪２Ｆ及び後輪２Ｒの車輪１輪当たりのコーナリングスティフネスであり、Ｉ_Ｚは車両のヨー慣性モーメントであり、Ａはスタビリティファクターである。 The second maximum acceleration/deceleration calculation unit 51m determines the frequency of the yaw rate of the own vehicle 1 based on the target vehicle speed V _Tar (i) at the point of interest, the turning curvature ρ(i), and the curvature change ρ'(i). The maximum deceleration at which is lower than the resonance frequency is calculated as the second maximum deceleration Ax2(i).
Specifically, the second maximum acceleration/deceleration calculation unit 51m calculates the resonance frequency ω _n of the yaw rate of the host vehicle 1 based on the following equation (16) using the motion characteristic value of the host vehicle 1.

C _F and C _R , which are the dynamic characteristic values of the own vehicle 1 in equation (16), are the cornering stiffness per wheel of the front wheel 2F and rear wheel 2R, respectively, and I _Z is the yaw inertia moment of the vehicle, A is the stability factor.

上式（１７）の最大ヨーレイト変化量γ’_Ｍａｘで自車両１のヨーレイト変化量を制限すると、自車両１に生じるヨーレイト周波数は、Ｋω_ｎ以下に制限される。例えばゲインＫは、整数ｎを分母とする分数（１／ｎ）に設定してよい。この場合、自車両１に生じるヨーレイト周波数をω_ｎ／ｎ以下に制限できる。
第２最大加減速度演算部５１ｍは、最大ヨーレイト変化量γ’_Ｍａｘと、旋回曲率ρ（ｉ）と、曲率変化ρ’（ｉ）と、目標車速Ｖ_Ｔａｒ（ｉ）とに基づいて、次式（１８）に従って第２最大減速度Ａｘ２（ｉ）を算出する。

The second maximum acceleration/deceleration calculation unit 51m calculates the speed of the host vehicle 1 based on the target vehicle speed V _Tar (i), the turning curvature ρ (i), and the maximum yaw rate setting value γ _Max according to the following equation (17). The maximum yaw rate change amount γ' _Max , which is the upper limit of the amount of yaw rate change (ie, yaw acceleration) that occurs, is calculated.

When the yaw rate change amount of the own vehicle 1 is limited by the maximum yaw rate change amount γ' _Max in the above equation (17), the yaw rate frequency generated in the own vehicle 1 is limited to Kω _n or less. For example, the gain K may be set to a fraction (1/n) with an integer n as the denominator. In this case, the yaw rate frequency generated in the own vehicle 1 can be limited to ω _n /n or less.
The second maximum acceleration/deceleration calculation unit 51m calculates the following equation based on the maximum yaw rate change amount γ' _Max , the turning curvature ρ(i), the curvature change ρ'(i), and the target vehicle speed V _Tar (i). The second maximum deceleration Ax2(i) is calculated according to (18).

第２最大加減速度演算部５１ｍは、最大横加加速度Ｊｙ_Ｍａｘと、旋回曲率ρ（ｉ）と、曲率変化ρ’（ｉ）と、目標車速Ｖ_Ｔａｒ（ｉ）とに基づいて、次式（２０）に従って第２最大減速度Ａｘ２（ｉ）を算出する。

The second maximum acceleration/deceleration calculation unit 51m calculates the second maximum deceleration Ax2(i) based on the maximum lateral jerk Jy _Max , which is the upper limit of the lateral jerk generated in the host vehicle 1, that is, the lateral jerk (jerk). You may. In this case, the second maximum acceleration/deceleration calculation unit 51m calculates the following equation (19) based on the target vehicle speed V _Tar (i), the turning curvature ρ(i), and the maximum lateral acceleration setting value A _yMax . Calculate the maximum lateral jerk Jy _Max .

The second maximum acceleration/deceleration calculation unit _51m calculates _the following equation (20 ), the second maximum deceleration Ax2(i) is calculated.

The selector 51n calculates the maximum speed by using the smaller of the maximum deceleration candidate Axc output from the selector 51k and the second maximum deceleration Ax2(i) as the maximum deceleration _Ax (i) at the point of interest i. It outputs to the section 51a and the load calculation section 51c. With the above steps, the calculation for the point of interest i is completed.
After that, when the point of interest i is moved backward one place and the calculation for the next point of interest i is started, the maximum deceleration A _x (i+1) calculated at the previous point of interest (i.e. point (i+1)) is , are used to calculate the target vehicle speed V _Tar (i) and the maximum deceleration A _x (i) at the new point of interest i.

FIG. 7 is a block diagram of an example of the functional configuration of the forward calculation section 52.
The forward calculation unit 52 sets a point one point ahead of the current position of the host vehicle 1 as the first point of interest i, and sequentially moves the point of interest i forward one by one to the farthest point. The maximum acceleration A _x (i) and the target vehicle speed V _Tar (i) are calculated respectively.
The forward calculation section 52 includes a maximum speed calculation section 52a, selectors 52b, 52k, and 52n, a load calculation section 52c, a target lateral force calculation section 52d, a maximum lateral force calculation section 52e, and a target longitudinal force calculation section 52h. , a maximum longitudinal force calculation section 52i, a first maximum acceleration/deceleration calculation section 52j, and a second maximum acceleration/deceleration calculation section 52m.

式（２１）のΔｓ（ｉ）は、注目地点ｉと地点（ｉ－１）との間の距離である。 In the calculation at the first point of interest i, the maximum speed calculation unit 52a calculates the current position of the host vehicle 1 as the target vehicle speed V _Tar (i-1) of the point (i-1) one place behind the point of interest i. The target vehicle speed of the first vehicle speed profile V _in is set, and the maximum acceleration setting value A _xMax , which is preset as the maximum allowable acceleration, is set as the maximum acceleration A _x (i-1) at the point (i-1).
For calculations at the second and subsequent points of interest, input the target vehicle speed V _Tar (i-1) and maximum acceleration A _x (i-1) calculated at the previous point (i.e., point (i-1)). do.
The maximum speed calculation unit 52a sets the speed limit value of the following equation (21) according to the target vehicle speed V _Tar (i-1) and the maximum acceleration A _x (i-1) at the previous point (i-1). do.

Δs(i) in equation (21) is the distance between the point of interest i and the point (i-1).

フォワード演算部５２は、目標車速Ｖ_Ｔａｒ（ｉ）を注目地点ｉにおける第３車速プロファイルＶ_ｏｕｔの目標車速Ｖ_ｏｕｔ（ｉ）として出力する。 The selector 52b sets the target vehicle speed V _Tar (i) at the point of interest i by limiting the target vehicle speed V _in (i) of the first vehicle speed profile V _in at the point of interest i according to the following equation (22).

The forward calculation unit 52 outputs the target vehicle speed V _Tar (i) as the target vehicle speed V _out (i) of the third vehicle speed profile V _out at the point of interest i.

The load calculation unit 52c calculates the pitch of the vehicle body of the host vehicle 1 according to the maximum acceleration A _x (i-1) at the point (i-1) one point ahead, based on the following equations (23) and (24). A front wheel load Fz _F (i), which is the load on the front wheel 2F based on the motion, and a rear wheel load Fz _R (i), which is the load on the rear wheel 2R, are calculated.

Forward calculation unit 52 includes target lateral force calculation unit 52d, maximum lateral force calculation unit 52e, target longitudinal force calculation unit 52h, maximum longitudinal force calculation unit 52i, first maximum acceleration/deceleration calculation unit 52j, selector 52k, and second maximum acceleration/deceleration. The functions of the calculation section 52m and the selector 52n are the target lateral force calculation section 51d, maximum lateral force calculation section 51e, target longitudinal force calculation section 51h, maximum longitudinal force calculation section 51i, and first maximum acceleration/deceleration calculation of the backward calculation section 51. The functions are similar to those of the section 51j, the selector 51k, the second maximum acceleration/deceleration calculation section 51m, and the selector 51n. However, _{"maximum deceleration Ax", "first maximum deceleration A x 1} ", "second maximum deceleration A _x 2", "maximum deceleration candidate Axc", "maximum "Deceleration setting value A _{x Max} " and "brake distribution ratio" are respectively "maximum acceleration A _x ", "first maximum acceleration A _x 1", "second maximum acceleration A _x 2", "maximum acceleration candidate Axc", It is read as "maximum acceleration setting value A _{x Max} " and "driving force distribution ratio".

(motion)
FIG. 8 is an explanatory diagram of an example of the vehicle speed control method according to the embodiment. In step S1, the geometric calculation unit 50 calculates a first vehicle speed profile V _in that is a profile of the target vehicle speed of the own vehicle 1.
In step S2, the backward calculation unit 51 limits the first vehicle speed profile V _in so that the friction limit is not exceeded during deceleration and the yaw rate frequency of the host vehicle 1 is less than the resonance frequency. Set _B.
FIG. 9 is a flowchart of an example of the process of step S2 in FIG. Here, the processes of steps S10 to S18 are repeated while moving the point of interest i backward one by one from a point one place behind the farthest point toward the current position of the host vehicle 1.

In step S10, the maximum speed calculation unit 51a and the selector 51b set the _target of the first vehicle speed profile V in at the point of interest i based on the maximum deceleration A _x (i+1) of the point (i+1) one point ahead of the point of interest i. The target vehicle speed V _B (i) of the second vehicle speed profile V _B is calculated by limiting the vehicle speed V _in (i).
In step S11, the target lateral force calculation unit 51d calculates the front wheel target lateral force Fy _ReqF (i) and the rear wheel target lateral force Fy _ReqR (i).

In step S12, the maximum lateral force calculation unit 51e calculates the front wheel maximum lateral force Fy _MaxF (i) and the rear wheel maximum lateral force Fy _MaxR (i).
In step S13, the target longitudinal force calculation unit 51h calculates the front wheel target longitudinal force Fx _ReqF (i) and the rear wheel target longitudinal force Fx _ReqR (i).
In step S14, the maximum longitudinal force calculation unit 51i calculates the front wheel maximum longitudinal force Fx _MaxF (i) and the rear wheel maximum longitudinal force Fx _MaxR (i).

In step S15, the first maximum acceleration/deceleration calculation unit 51j calculates _the front wheel maximum longitudinal force Fx _MaxF (i), the rear wheel maximum longitudinal force Fx MaxR (i), the front wheel target longitudinal force Fx _ReqF (i), and the rear wheel target longitudinal force Fx. By limiting _ReqR (i), the maximum longitudinal force Fx _Max (i) that can be generated in the host vehicle 1 without causing the friction forces of the front wheels 2F and rear wheels 2R to exceed the friction limit is calculated. The first maximum acceleration/deceleration calculation unit 51j calculates the first maximum deceleration Ax1(i)=Fx _Max (i)/m caused by the maximum longitudinal force Fx _Max (i).
In step S16, the selector 51k selects the smaller of the first maximum deceleration Ax1(i) and the maximum deceleration setting value _AxMax as the maximum deceleration candidate Axc.
In step S17, the second maximum acceleration/deceleration calculation unit 51m calculates the maximum deceleration at which the frequency of the yaw rate of the host vehicle 1 becomes lower than the resonance frequency as the second maximum deceleration Ax2(i).
In step S18, the selector 51n selects the smaller of the second maximum deceleration Ax2(i) and the maximum deceleration candidate Axc as the maximum deceleration _Ax (i).
When the above steps S10 to S18 are repeated until the point of interest i reaches the current position of the host vehicle 1, the process then proceeds to step S3 in FIG.

Refer to FIG. In step S3, the forward calculation unit 52 limits the second vehicle speed profile _VB so that the friction limit is not exceeded during acceleration and the yaw rate frequency of the host vehicle 1 is less than the resonance frequency, so that the third vehicle speed profile V _out Set.
The processing of the forward calculation section 52 is the same as the processing of the backward calculation section 51 in step S2 except for the following points (1) and (2).
(1) Move the point of interest i forward one point at a time from the point one place ahead of the current position of the host vehicle 1 to the farthest point.
(2) "Maximum deceleration A _x ", "First maximum deceleration A _x 1", "Second maximum deceleration A _x 2", "Maximum deceleration candidate Axc", "Maximum deceleration setting value A _{x Max} " , "brake distribution ratio" are respectively "maximum acceleration A _x ", "first maximum acceleration A _x 1", "second maximum acceleration A _x 2", "maximum acceleration candidate Axc", and "maximum acceleration setting value A _{x Max"} . ", read as "driving force distribution ratio."
In step S4, the vehicle control unit 22 controls the speed of the host vehicle 1 by driving the actuator 18 based on the third vehicle speed profile V _out . The process then ends.

(Effects of embodiment)
(1) The controller 17 sets a target traveling trajectory for the own vehicle 1, calculates the resonance frequency of the yaw rate of the own vehicle 1 based on the motion characteristic values of the own vehicle 1, and causes the own vehicle 1 to travel on the target traveling trajectory. A target vehicle speed is set such that the frequency of the yaw rate of the host vehicle 1 while traveling on the target travel trajectory is less than the resonance frequency, and the vehicle speed of the host vehicle 1 is controlled based on the target vehicle speed.
As a result, the target vehicle speed can be set so that the frequency of the yaw rate of the own vehicle 1 traveling on the target travel trajectory does not exceed the resonance frequency, so it is possible to suppress the behavior of the own vehicle 1 from becoming unstable due to the frequency of the yaw rate. .

(2) The controller 17 sets a first vehicle speed profile, which is a profile of the target vehicle speed of the own vehicle 1, to a point where the lateral acceleration of the center of gravity of the own vehicle 1 is equal to or less than a predetermined value at each point on the target traveling trajectory, and the first vehicle speed profile is a profile of the target vehicle speed of the own vehicle 1. The yaw rate of the own vehicle 1 is set to be below a predetermined value at each point, and either acceleration or deceleration is limited so that the frequency of the yaw rate of the own vehicle 1 is less than the resonance frequency at each point. The maximum speed at that time is calculated as the first maximum speed, and a second vehicle speed profile is set by limiting the first vehicle speed profile by the first maximum speed at each point. By calculating the maximum speed when either acceleration or deceleration is limited to be less than the resonance frequency as the second maximum speed, and limiting the second vehicle speed profile at the second maximum speed at each point. A third vehicle speed profile may be set, and the vehicle speed of the host vehicle 1 may be controlled based on the third vehicle speed profile.
Thereby, the vehicle speed can be controlled so as not to exceed both the deceleration and acceleration allowed for the own vehicle.

(3) The controller 17 sets one of the points closer to the own vehicle 1 and the farther point in front of the own vehicle 1 as the first point and the other as the second point among the respective points on the target traveling trajectory. The maximum allowable yaw rate change amount for the own vehicle 1 at the first point is calculated based on the curvature at The maximum acceleration/deceleration at which the yaw rate change amount of the vehicle 1 is equal to or less than the maximum yaw rate change amount may be calculated, and the target vehicle speed at the second point may be set based on the maximum acceleration/deceleration.
In this case, the controller 17 determines the maximum yaw rate change amount based on the curvature at the first point, the target speed of the own vehicle 1 at the first point, the maximum allowable yaw rate, and the product of the resonance frequency and a gain of less than 1. may be calculated.
Then, the maximum acceleration/deceleration may be calculated based on the maximum yaw rate change amount, the curvature and curvature change at the first point, and the target speed of the host vehicle 1 at the first point.
Thereby, it is possible to calculate the maximum yaw rate change at which the frequency of the yaw rate of the own vehicle 1 is less than the resonance frequency, and to set the target vehicle speed by limiting the maximum acceleration/deceleration based on the maximum yaw rate change.

(4) The controller 17 sets one of the points closer to the own vehicle 1 and the farther point in front of the own vehicle 1 as the first point and the other as the second point among the respective points on the target traveling trajectory. The maximum lateral jerk allowed for the own vehicle 1 at the first point is calculated based on the curvature at The maximum acceleration/deceleration at which the lateral jerk of the vehicle 1 becomes less than or equal to the maximum lateral jerk may be calculated, and the target vehicle speed at the second point may be set based on the maximum acceleration/deceleration.
In this case, the controller 17 determines the maximum lateral acceleration based on the curvature at the first point, the target speed of the host vehicle 1 at the first point, the maximum allowable lateral acceleration, and the product of the resonance frequency and the gain less than 1. Acceleration may also be calculated.
Then, the maximum acceleration/deceleration may be calculated based on the maximum lateral jerk, the curvature and curvature change at the first point, and the target speed of the host vehicle 1 at the first point.
Thereby, the maximum lateral jerk at which the frequency of the yaw rate of the own vehicle 1 is less than the resonance frequency can be calculated, and the target vehicle speed can be set by limiting the maximum acceleration/deceleration based on the maximum lateral jerk.

22... Vehicle control section, 50... Geometric calculation section, 51... Backward calculation section, 51a, 522a... Maximum speed calculation section, 51b, 51k, 51n, 52b, 52k, 52n... Selector, 51c, 52c... Load calculation section , 51d, 52d...Target lateral force calculation section, 51e, 52e...Maximum lateral force calculation section, 51f, 52f...Maximum steering angle calculation section, 51g, 52g...Maximum lateral force restriction section, 51h, 52h...Target longitudinal force calculation section Parts, 51i, 52i...Maximum longitudinal force calculation section, 51j, 52j...First maximum acceleration/deceleration calculation section, 51m, 52m...Second maximum acceleration/deceleration calculation section

Claims (9)

Set the target travel trajectory for your vehicle,
calculating a resonance frequency of the yaw rate of the own vehicle based on the motion characteristic value of the own vehicle;
setting a target vehicle speed at which the host vehicle travels on the target travel trajectory such that a frequency of a yaw rate at which the host vehicle travels on the target travel trajectory is less than the resonance frequency;
controlling the vehicle speed of the host vehicle based on the target vehicle speed;
A vehicle speed control method characterized by: A first vehicle speed profile that is a profile of the target vehicle speed of the host vehicle is set such that the lateral acceleration of the center of gravity of the host vehicle is equal to or less than a predetermined value at each point on the target travel trajectory, and the first vehicle speed profile is a profile of the target vehicle speed of the host vehicle. Set the yaw rate of your vehicle to be below a predetermined value,
At each of the points, the maximum speed when either acceleration or deceleration is limited so that the frequency of the yaw rate of the own vehicle is less than the resonance frequency is calculated as a first maximum speed,
setting a second vehicle speed profile by limiting the first vehicle speed profile at the first maximum speed at each of the points;
At each point, the maximum speed when either acceleration or deceleration is limited so that the frequency of the yaw rate of the own vehicle is less than the resonance frequency is calculated as a second maximum speed,
setting a third vehicle speed profile by limiting the second vehicle speed profile at the second maximum speed at each of the points;
controlling the vehicle speed of the host vehicle based on the third vehicle speed profile;
The vehicle speed control method according to claim 1, characterized in that: Among the points on the target travel trajectory, one of a point closer to the vehicle in front of the vehicle and a point further away from the vehicle is a first point and the other is a second point, and the curvature at the first point; calculating a maximum yaw rate change allowed for the host vehicle at the first point based on the target speed of the host vehicle at the first point, a predetermined maximum allowable yaw rate, and the resonance frequency;
Calculating the maximum acceleration/deceleration at which the amount of change in the yaw rate of the own vehicle is equal to or less than the amount of change in the maximum yaw rate,
setting the target vehicle speed at the second point based on the maximum acceleration/deceleration;
The vehicle speed control method according to claim 2, characterized in that: 4. The maximum acceleration/deceleration is calculated based on the maximum yaw rate change amount, the curvature and curvature change at the first point, and the target speed of the own vehicle at the first point. Vehicle speed control method described. Calculating the maximum yaw rate change amount based on the curvature at the first point, the target speed of the own vehicle at the first point, the maximum allowable yaw rate, and the product of the resonance frequency and a gain less than 1. The vehicle speed control method according to claim 3 or 4, characterized in that: Among the points on the target travel trajectory, one of a point closer to the vehicle in front of the vehicle and a point further away from the vehicle is a first point and the other is a second point, and the curvature at the first point; Calculating the maximum lateral jerk allowed for the own vehicle at the first point based on the target speed of the own vehicle at the first point, a predetermined maximum allowable lateral acceleration, and the resonance frequency;
Calculating the maximum acceleration/deceleration at which the lateral jerk of the host vehicle is equal to or less than the maximum lateral jerk;
setting the target vehicle speed at the second point based on the maximum acceleration/deceleration;
The vehicle speed control method according to claim 2, characterized in that: 7. The maximum acceleration/deceleration is calculated based on the maximum lateral jerk, the curvature and curvature change at the first point, and the target speed of the host vehicle at the first point. vehicle speed control method. Calculating the maximum lateral jerk based on the curvature at the first point, the target speed of the vehicle at the first point, the maximum allowable lateral acceleration, and the product of the resonance frequency and a gain of less than 1. The vehicle speed control method according to claim 6 or 7, characterized in that: a drive device that generates driving force for the own vehicle;
a braking device that generates braking force for the own vehicle;
A target travel trajectory of the host vehicle is set, a resonance frequency of the yaw rate of the host vehicle is calculated based on the motion characteristic value of the host vehicle, and a target vehicle speed at which the host vehicle travels on the target travel trajectory is calculated based on the motion characteristic value of the host vehicle. a controller that sets a frequency of a yaw rate when the host vehicle is traveling on the target travel trajectory to be less than the resonance frequency, and controls at least one of the drive device or the brake device based on the target vehicle speed. A vehicle speed control device characterized by:

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