21 or the stereo camera 22, or weather information received via the communication unit 40, for example.

More specifically, for example, the first speed calculation unit 126a sets a threshold value in the weather condition such as the rainfall amount, the snowfall amount, and the fog concentration. When a value exceeds the threshold value, the first speed calculation unit 126a specifies the sensing range SR reduced from the previous sensing range SR. In the example illustrated in FIG. 7, the first speed calculation unit 126a specifies a sensing range SR₀of the most enlarged detectable distance D₀until the rainfall amount, the snowfall amount, or the fog concentration exceeds a first threshold value.

In addition, in the example illustrated in FIG. 7, until the rainfall amount, the snowfall amount, or the fog concentration exceeds the first threshold value and exceeds a second threshold value, the first speed calculation unit 126a specifies a sensing range SR₁having a detectable distance D₁reduced from the previous sensing range SR₀. Furthermore, when the rainfall amount, the snowfall amount, or the fog concentration exceeds the first threshold value and exceeds the second threshold value, the first speed calculation unit 126a specifies a sensing range SR₂having a detectable distance D₂reduced from the previous sensing range SR₁.

In addition, as in the example illustrated in FIG. 8, when the brightness falls below a predetermined threshold value, such as at night or in a tunnel where no illumination is installed, the first speed calculation unit 126a specifies a sensing range SR₃corresponding to the illumination range of the headlight reduced from the previous sensing range SR₀. Furthermore, as in the example illustrated in FIG. 9, for example, when a blind spot BA occurs in the sensing range SR of the external environment sensor 20 due to an oncoming vehicle, a guardrail, or a building, the target speed calculation unit 126 specifies the sensing range SR from which the blind spot BA has been excluded.

Then, as illustrated in FIGS. 4 and 10, for example, the first speed calculation unit 126a executes the process P2 of acquiring the target route TR. As described above, for example, the target route TR is calculated by the target route calculation unit 122, input to the target speed calculation unit 126, and acquired by the first speed calculation unit 126a.

Then, as illustrated in FIGS. 4 and 10, for example, the first speed calculation unit 126a executes a process P3 of calculating a route length l₁of the target route TR up to an outer edge SRp of the sensing range SR. In this process P3, the first speed calculation unit 126a calculates the route length l₁of the target route TR of the vehicle 10 to the outer edge SRp of the sensing range SR based on the sensing range SR specified in the above-described process P1 and the target route TR acquired in the above-described process P2, for example.

Then, the first speed calculation unit 126a executes a process P4 of calculating a first speed V₁as illustrated in FIG. 4, for example. In this process P4, the first speed calculation unit 126a calculates an upper limit deceleration g₁of the vehicle 10 by using the route length l₁of the target route TR up to the outer edge SRp of the sensing range SR, which has been calculated in the above-described process P3 and the friction coefficient μ of the road surface, which is acquired from the friction coefficient acquisition unit 125, for example. The upper limit deceleration g₁is, for example, an upper limit deceleration at the time of emergency stop of the vehicle 10, which is calculated based on the friction coefficient μ of the road surface on which the vehicle 10 travels and further multiplied by the safety factor.

Then, the first speed calculation unit 126a calculates the first speed V₁at which the vehicle 10 can stop at the stop position before the outer edge SRp of the sensing range SR by, for example, the following expression (1). The first speed V₁is a speed at which the vehicle 10 traveling along the target route TR can stop at the stop position before the outer edge SRp of the sensing range SR of the external environment sensor 20 at a deceleration that does not exceed the upper limit deceleration g₁.

[Math. 1]

V₁=√{square root over (2·g₁·l₁)} (1)

Then, as illustrated in FIGS. 4 and 11, the second speed calculation unit 126b executes processes P5 and P6 of calculating a second speed V₂at which the vehicle 10 can follow the target route TR.

More specifically, for example, the second speed calculation unit 126b first acquires an upper limit deceleration g₂before the vehicle 10 enters the curve. For example, the upper limit deceleration g₂of the vehicle 10 before entering the curve is set to a predetermined deceleration that does not cause an occupant of the vehicle 10 to feel uncomfortable, and is stored in the storage device of the vehicle control device 100 in advance.

In addition, the second speed calculation unit 126b calculates an upper limit lateral acceleration g₃when the vehicle passes through curves C1, C2, and C3 of the target route TR included in the sensing range SR of the external environment sensor 20. The upper limit lateral acceleration g₃can be set to the lateral acceleration at which the vehicle 10 does not slip, for example, by a centrifugal force acting on the vehicle 10 that travels on each of the curves C1, C2, and C3.

Such a lateral acceleration can be calculated, for example, based on the friction coefficient μ between the road surface and the tire of the vehicle 10, a grounding area with the road surface, the gravitational acceleration, the curvature radii r₁, r₂, and r₃of the respective curves C1, C2, and C3, and the like. The curvature radii r₁, r₂, and r₃of the curves C1, C2, and C3 may be obtained from, for example, the map data 60, or may be obtained by acquiring the road shape in front of the vehicle 10 by the monocular camera 21, the stereo camera 22, the laser radar 24, or the like.

Then, the second speed calculation unit 126b calculates second speeds V₂₁, V₂₂, V₂₃, . . . , and V_2iof the vehicle 10 when the vehicle travels on the curves C1, C2, C3, . . . , and Ci of the target route TR included in the sensing range SR, for example, by using the following expression (2). In the following expression (2) l₂₁, l₂₂, l₂₃, . . . , and l_2iare route lengths from the vehicle 10 to the entry positions of the respective curves C1, C2, C3, . . . , and Ci as illustrated in FIG. 11.

V
21

=

2
·

g
2

·

l
21

+

g
3

·

r
1

V
22

=

2
·

g
2

·

l
22

+

g
3

·

r
2

V
23

=

2
·

g
2

·

l
23

+

g
3

·

r
3

⋮

V

2
⁢
i

=

2
·

g
2

·

l

2
⁢
i

+

g
3

·

r
1

}

(
2
)

As illustrated in FIG. 11, each of the second speeds V₂₁, V₂₂, V₂₃, . . . , and V_2iin the above expression (2) is a speed at which the vehicle can decelerate at the upper limit deceleration g₂up to the entry positions C1i, C2i, C3i, . . . , and Cii of the respective curves C1, C2, C3, . . . , and Ci and the respective curves C1, C2, C3, . . . , and Ci can be bent. That is, for example, the second speed calculation unit 126b calculates the second speeds V₂₁, V₂₂, V₂₃, . . . , and V_2iat which the vehicle 10 can decelerate up to the entry positions C1i, C2i, C3i, . . . , and Cii at a deceleration that does not exceed the predetermined upper limit deceleration g₂.

In the example illustrated in FIG. 11, the second speed calculation unit 126b calculates the second speeds V₂₁, V₂₂, V₂₃, . . . , and V_2ifor the respective curves C1, C2, C3, . . . , and Ci having different curvature radii r₁, r₂, r₃, . . . , and r_i. The second speeds can be calculated in other units. For example, the second speed calculation unit 126b may calculate the second speeds V₂₁, V₂₂, V₂₃, . . . , and V_2iat which the vehicle 10 can decelerate with a deceleration that does not exceed the predetermined upper limit deceleration g₂up to the entry position in each section in units of sections obtained by dividing the target route TR by a predetermined division length.

Note that, for example, the second speed calculation unit 126b may calculate each of the second speeds V₂₁, V₂₂, V₂₃, . . . , and V_2iby using only the upper limit lateral acceleration g₃without using the upper limit deceleration g₂. In this case, the term including the upper limit deceleration g₂in the above expression (2) becomes zero. Each of the second speeds V₂₁, V₂₂, V₂₃, . . . , and V_2iis a speed at which the vehicle can bend on each of the curves C1, C2, C3, . . . , and Ci, that is, a speed at which the vehicle 10 can follow the target route TR calculated using the curvature radii r₁, r₂, r₃, . . . , and r_iof the target route TR and the friction coefficient μ of the road surface.

For example, when the upper limit lateral acceleration g₃calculated as described above exceeds the range of the lateral acceleration that does not cause the occupant of the vehicle 10 to feel uncomfortable, the second speed calculation unit 126b may set the upper limit lateral acceleration of the range as the upper limit lateral acceleration g₃. That is, the second speed calculation unit 126b may calculate the second speed V₂at which the vehicle can follow the target route TR at a lateral acceleration that does not exceed the predetermined upper limit lateral acceleration g₃, such as a lateral acceleration that does not cause the occupant of the vehicle 10 to feel uncomfortable.

Then, as illustrated in FIG. 4, the second speed calculation unit 126b executes a process P6 of selecting the minimum second speed V₂. In this process P6, the second speed calculation unit 126b sets the minimum speed among the plurality of calculated second speeds V₂₁, V₂₂, V₂₃, . . . , and V_2ias the second speed V₂by, for example, using the following expression (3). As a result, the second speed V₂can be set to a speed at which the vehicle 10 can follow the entire target route TR included in the sensing range SR.

[Math. 3]

V₂=min(V₂₁,V₂₂,V₂₃, . . . ,V_2i) (3)

Then, the target speed setting unit 126f executes a process P7 of calculating the target speed V_tgt. In this process P7, the target speed setting unit 126f selects the minimum speed out of the first speed V₁and the second speed V₂and sets the selected minimum speed as the target speed V_tgtby using, for example, the following expression (4). As a result, the target speed V_tgtcan be set to a speed at which the vehicle 10 can stop at the stop position before the outer edge SRp of the sensing range SR of the external environment sensor 20 and the vehicle 10 can follow the target route TR.

[Math. 4]

V_tgt=min(V₁,V₂) (4)

Then, the travel planning unit 120 executes a process P8 of outputting the target speed V_tgtcalculated and set by the target speed calculation unit 126 as described above to the travel control unit 130 illustrated in FIG. 2, for example. Here, for example, the travel planning unit 120 outputs the target route TR to the travel control unit 130 together with the target speed V_tgt. The travel control unit 130 outputs control commands to the brake control unit 140, the steering control unit 150, and the driving force control unit 160 based on the target speed V_tgtand the target route TR input from the travel planning unit 120.

The brake control unit 140, the steering control unit 150, and the driving force control unit 160 respectively control the hydraulic unit 19, the brake caliper 18, the power steering 14, and the power source 11 based on the control commands input from the travel control unit 130. This enables automatic driving of the vehicle 10.

The operation of the vehicle control device 100 of the present embodiment will be described below.

The vehicle control device 100 in the present embodiment includes the target speed calculation unit 126 that calculates the target speed V_tgtof the vehicle 10. The target speed calculation unit 126 includes the first speed calculation unit 126a, the second speed calculation unit 126b, and the target speed setting unit 126f. The first speed calculation unit 126a calculates, by using the route length l₁of the target route TR of the vehicle 10 up to the outer edge SRp of the sensing range SR of the external environment sensor 20 of the vehicle 10 and the friction coefficient μ of the road surface, the first speed V₁at which the vehicle 10 can stop at the stop position before the outer edge SRp. The second speed calculation unit 126b calculates, by using the curvature radii r₁, r₂, r₃, . . . , and r_iof the target route TR and the friction coefficient μ, the second speed V₂at which the vehicle 10 can follow the target route TR. Then, the target speed setting unit 126f selects the minimum speed out of the first speed V₁and the second speed V₂and sets the minimum speed to the target speed V_tgt.

With such a configuration, even when the target route TR included in the sensing range SR includes the curves C1, C2, C3, . . . , and Ci, the vehicle control device 100 can prevent the slip of the vehicle 10 and cause the vehicle 10 to travel with following the target route TR. Further, even when there is an obstacle outside the sensing range SR of the external environment sensor 20, it is possible to reliably stop the vehicle 10 before the obstacle. Therefore, according to the present embodiment, it is possible to provide the vehicle control device 100 capable of suppressing a decrease in safety due to an obstacle that cannot be detected by the external environment sensor 20 and improving the safety of the vehicle 10 while the vehicle 10 is traveling on the target route TR including the curves C1, C2, C3, . . . , and Ci.

In addition, in the vehicle control device 100 in the present embodiment, the first speed calculation unit 126a calculates the first speed V₁at which the vehicle 10 can stop at the stop position at the deceleration that does not exceed the predetermined upper limit deceleration g₁. The second speed calculation unit 126b calculates the second speed V₂at which the vehicle can follow the target route TR at the lateral acceleration that does not exceed the predetermined upper limit lateral acceleration g₃.

With such a configuration, the vehicle control device 100 in the present embodiment can more reliably stop the vehicle 10 at the stop position before the outer edge SRp of the sensing range SR by using the above-described upper limit deceleration at the time of emergency stop of the vehicle 10 as the predetermined upper limit deceleration g₁. In addition, by using the upper limit deceleration that does not causes the occupant of the vehicle 10 to feel uncomfortable, as the predetermined upper limit deceleration g₁, it is possible to stop the vehicle 10 at the stop position before the outer edge SRp of the sensing range SR without causing the occupant of the vehicle 10 to feel uncomfortable. Furthermore, by using the upper limit lateral acceleration that does not cause the occupant of the vehicle 10 to feel uncomfortable, as the predetermined upper limit lateral acceleration g₃, it is possible to pass through the target route TR including the curves C1, C2, C3, . . . , and Ci without causing the occupant of the vehicle 10 to feel uncomfortable.

In addition, in the vehicle control device 100 in the present embodiment, the second speed calculation unit 126b calculates the second speed V₂at which the vehicle 10 can decelerate at a deceleration that does not exceed the predetermined upper limit deceleration g₂up to the entry positions C1i, C2i, C3i, . . . , and Cii of the curves C1, C2, C3, . . . , and Ci having different curvature radii r₁, r₂, r₃, . . . , and r_iincluded in the target route TR.

With such a configuration, the vehicle control device 100 in the present embodiment can use, as the predetermined upper limit deceleration g₂, the upper limit deceleration that does not cause the occupant of the vehicle 10 to feel uncomfortable. As a result, it is possible to decelerate the vehicle 10 to a speed at which the vehicle 10 can bend on the curves C1, C2, C3, . . . , and Ci to the entry positions C1i, C2i, C3i, . . . , and Cii of the curves C1, C2, C3, . . . , and Ci without causing the occupant of the vehicle to feel uncomfortable.