Apparatus and method for controlling inter-vehicle distance to another vehicle traveling ahead of automotive vehicle equipped with the apparatus and method

• US 6,233,516 B1
• Filed: 01/14/1999
• Issued: 05/15/2001
• Est. Priority Date: 01/14/1998
• Status: Expired due to Term

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Egawa, Kenichi
• Primary Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US09/232,025
• Time in Patent Office: 852 Days
• Field of Search: 701/93, 701/96, 701/300, 701/301, 180/167, 180/168, 180/169, 180/170, 340/903, 340/436, 340/904, 340/901, 340/902, 356/3.16, 356/5.05, 356/5.01, 356/3, 356/3.1, 250/559.38, 250/222.1, 342/70, 342/71, 342/69, 342/61, 342/73, 342/118, 702/97
• US Class Current: 701/96
• CPC Class Codes: B60K 31/0008 including means for detecting potential obstacles in vehicle path
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 2720/106 Longitudinal acceleration
• CPC Class Codes: B60W 2754/30 Longitudinal distance
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
• CPC Class Codes: G01S 2013/93185 Controlling the brakes
• CPC Class Codes: G01S 2013/9319 Controlling the accelerator
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 2013/9321 Velocity regulation, e.g. cruise control

Abstract

In control apparatus and method for controlling an inter-vehicle distance to another vehicle traveling ahead of the vehicle, an inter-vehicle distance from the vehicle to another vehicle running on a traffic lane at the detected inter-vehicle distance from the vehicle is detected through an inter-vehicle distance detector; a follow-up running control for the vehicle is performed by a vehicular running controller such that the vehicle runs behind the other vehicle, maintaining a predetermined inter-vehicle distance to the other vehicle; and a vehicular velocity variation inhibit command is generated and outputted to the vehicular running controller to maintain a vehicular running state immediately before the inter-vehicle distance detector changes from a first state in which the inter-vehicle distance to the other vehicle is being detected into a second state in which the inter-vehicle distance becomes indetectable is continued for a duration of time until the vehicle passes the traffic lane by the inter-vehicle distance immediately before the inter-vehicle distance detector changes from the first state into the second state.

Claims

1. A control apparatus for an automotive vehicle, comprising:

an inter-vehicle distance detector for detecting an inter-vehicle distance from a host vehicle to a preceding vehicle which is running on a traffic lane;

a vehicular running controller for performing a follow-up running control for the host vehicle such that the host vehicle runs behind the preceding vehicle, maintaining a predetermined inter-vehicle distance to the preceding vehicle; and

a vehicular velocity variation inhibit command generator for generating and outputting a vehicular velocity variation inhibit command to the vehicular running controller to maintain a vehicular running state immediately before the inter-vehicle distance detector changes from a first state in which the inter-vehicle distance to the preceding vehicle is being detected into a second state in which the inter-vehicle distance becomes indetectable, and the vehicular velocity variation inhibit command is continued for a duration of time until the host vehicle passes the traffic lane by the inter-vehicle distance immediately before the inter-vehicle distance detector changes from the first state into the second state.

2. A control apparatus for an automotive vehicle as claimed in claim 1, wherein the vehicular running controller recovers follow-up running control when the vehicular velocity variation inhibit command is received from the vehicular velocity variation inhibit command generator and when the inter-vehicle distance detector becomes detectable for a presence of the preceding running vehicle before the host vehicle has passed the traffic lane by the inter-vehicle distance which is immediately before the inter-vehicle distance detector changes from the first state into the second state.

3. A control apparatus for an automotive vehicle as claimed in claim 1, wherein the vehicular running controller includes a vehicular running state detector for detecting whether the vehicle is in a straight running state or in a turning state and wherein the vehicular running controller is in a vehicular acceleration control enabled state to enable the host vehicle to be accelerated when the following condition is satisfied:

at a time point at which the host vehicle has passed the traffic lane by the inter-vehicle distance which is immediately before the inter-vehicle distance detector changes from the first state into the second state from a time at which the vehicular velocity variation inhibit command is received from the vehicular velocity variation inhibit command generator, the inter-vehicle distance detector is indetectable for a presence of the preceding vehicle and the vehicular running state detector detects that the host vehicle is in the straight running state.

4. A control apparatus for an automotive vehicle as claimed in claim 1, wherein the vehicular running controller includes:

a vehicular running state detector for detecting whether the host vehicle is in a straight running state or in a turning state;

a turning radius estimator for estimating a radius of turn of the host vehicle on a basis of a result of detection by the vehicular running state detector; and

a first setter for setting a vehicular running state in accordance with the estimated turning radius of the host vehicle when the inter-vehicle distance detector is indetectable for the presence of the preceding vehicle and the vehicular running state detector detects that the host vehicle is running in the turning state at a time point at which the host vehicle has passed the traffic lane by the inter-vehicle distance which is immediately before the inter-vehicle distance detector changes from the first state into the second state from a time at which the vehicular velocity variation inhibit command is received from the vehicular velocity variation inhibit command generator.

5. A control apparatus for an automotive vehicle as claimed in claim 4, wherein the vehicular running controller includes:

a first determinator for determining whether the estimated turning radius of the host vehicle is equal to or below a deceleration required radius of turn equal to or below which the host vehicle is required to decelerate the host vehicle; and

a second setter for setting the host vehicle in a deceleration control enabled state to enable the host vehicle to be decelerated when the first determinator determines that the estimated radius of turn is equal to or below the deceleration required radius of turn.

6. A control apparatus for an automotive vehicle as claimed in claim 5, wherein the first setter sets the vehicular running controller in an acceleration control enabled state to enable the host vehicle to be accelerated when the estimated turning radius of the host vehicle is in excess of an acceleration enabling radius of turn which is larger than the deceleration required radius of turn.

7. A control apparatus for an automotive vehicle as claimed in claim 6, wherein the inter-vehicle distance detector comprises a radar unit mounted on a predetermined front end of the host vehicle for scanning a beam over a given scanning angle in a width-wise direction of the host vehicle and receiving beams reflected from at least one object present within a forward detection zone defined by the scanning angle to detect the object.

8. A control apparatus for an automotive vehicle as claimed in claim 6, which further comprises a vehicle velocity detector for detecting a present velocity (Vn) of the host vehicle and wherein the vehicular running controller reads the present inter-vehicle distance (L(n)) from the inter-vehicle distance detector and includes a first calculator for calculating a target vehicle velocity (V*(n)) so that a time duration (T₀) during which the host vehicle has reached to a position (L₀) behind the preceding vehicle running ahead of the host vehicle becomes constant in accordance with the following equation:

V*(n)×

(L(n)−

L₀)/T₀.

9. A control apparatus for an automotive vehicle as claimed in claim 8, wherein the vehicular running controller further includes:

a second calculator for calculating a velocity deviation (Δ

V(=V*(n)−

V(n))) between the target vehicle velocity and the present vehicle velocity; and

a third calculator for calculating an engine output command value (α

) in accordance with the following equation;

α

=K_PEΔ

V(n)+K_iE∫

Δ

V(n)+K_dEΔ

V′

(n)+f_E, wherein K_PE denotes a proportional gain, K_iE denotes an integration gain, K_dE denotes a differential gain, Δ

V′

denotes a differential value of Δ

V(n), and f_E denotes an engine output value corresponding to the calculated target vehicle velocity V*(n).

10. A control apparatus for an automotive vehicle as claimed in claim 9, wherein the vehicular running controller further includes:

a second determinator for determining whether the engine output command value (α

) is positive or not; and

a fourth calculator for calculating a target braking liquid pressure (P(n)) in accordance with the following equation when α

≦

0;

P(n)=−

(K<sub>PBΔ

V(n)+KiB</sub>∫

Δ

V(n)+K_dBΔ

V′

(n)), wherein K_PB denotes a proportional gain, K_iB denotes an integration gain, and K_dB denotes a differential gain.

11. A control apparatus for an automotive vehicle as claimed in claim 10, wherein the vehicular running controller further includes:

a second reader for reading the detected inter-vehicle distance (L) from the inter-vehicle distance detector; and

a third determinator for determining whether the presence of the preceding vehicle running ahead of the host vehicle is recognized by the inter-vehicle distance detector according to whether the detected inter-vehicle distance (L) is within a detection limit value (L_max) of the inter-vehicle distance detector and wherein the vehicle running controller maintains the present vehicular running state immediately before the third determinator determines that the presence of the preceding vehicle is not recognized.

12. A control apparatus for an automotive vehicle as claimed in claim 11, wherein the vehicular running controller further includes:

a fourth determinator for determining whether the host vehicle has passed the traffic lane by the inter-vehicle distance (L(n−

1)) which is immediately before the inter-vehicle distance detector detects that no preceding vehicle is present and wherein the third determinator becomes active again when the fourth determinator determines that the host vehicle has passed the traffic lane by the immediately before inter-vehicle distance (L(n−

1)).

13. A control apparatus for an automotive vehicle as claimed in claim 12, wherein the vehicular running state detector includes:

a steering angular displacement sensor for detecting a steering angular displacement (θ

) of a steering wheel of the host vehicle; and

a fifth determinator for determining whether the steering angular displacement is equal to or below a predetermined small threshold value (θ

so) so as to determine whether the host vehicle is in the straight running state or in the turning state.

14. A control apparatus for an automotive vehicle as claimed in claim 13, wherein the estimator estimates the turning radius (R) of the host vehicle on the basis of the present vehicle velocity (V(n)) and the steering angular displacement (θ

) when the fifth determinator determines that the steering angular displacement (θ

) is above the predetermined small threshold value (θ

>

θ

so).

15. A control apparatus for an automotive vehicle as claimed in claim 14, wherein the vehicular running controller includes an acceleration enabling flag (FA) which is set so as to enable the host vehicle to be accelerated when the steering angular displacement (θ

) is equal to or below the predetermined small threshold value (θ

≦

θ

).

16. A control apparatus for an automotive vehicle as claimed in claim 15, wherein the vehicular running controller includes:

a sixth determinator for determining whether the estimated radius of turn of the host vehicle (R) is in excess of the braking required radius of turn of the vehicle (R_B0);

a fifth calculator for calculating an optimum vehicle velocity (Vc) according to the estimated radius of turn of the host vehicle (R) when R≦

R_B0; and

a sixth calculator for calculating the target braking liquid pressure (P(n)) on the basis of a deviation (Δ

Vc) between the optimum vehicle velocity (Vc) and the present vehicle velocity (V(n)) when R≦

R_B0.

17. A control apparatus for an automotive vehicle as claimed in claim 16, wherein when R>

R_B0, the vehicular running controller is operated to maintain the present vehicular running state.

18. A control apparatus for an automotive vehicle as claimed in claim 17, wherein when α

≦

0, the vehicular running controller outputs a zero engine output command value (α

) to an engine output controller and calculates and outputs the present braking liquid pressure (P(n)) based on the velocity deviation (Δ

V(n)) to a braking controller so that the host vehicle is decelerated and wherein when α

>

0, the vehicular running controller outputs a zero target braking liquid pressure (P(n)=0) to the braking controller and the engine output command value (α

) to the engine output controller.

19. A control apparatus for an automotive vehicle, comprising:

inter-vehicle distance detecting means for detecting an inter-vehicle distance from a host vehicle to a preceding vehicle which is running on a traffic lane at the detected inter-vehicle distance from the host vehicle;

vehicular running controlling means for performing a follow-up running control for the host vehicle such that the host vehicle runs behind the preceding vehicle, maintaining a predetermined inter-vehicle distance to the preceding vehicle; and

vehicular velocity variation inhibit command generating means for generating and outputting a vehicular velocity variation inhibit command to the vehicular running controlling means to maintain a vehicular running state immediately before the inter-vehicle distance detecting means changes from a first state in which the inter-vehicle distance to the preceding vehicle is being detected into a second state in which the inter-vehicle distance becomes indetectable, and the vehicular velocity variation inhibit command is continued for a duration of time until the host vehicle passes the traffic lane by the inter-vehicle distance immediately before the inter-vehicle distance detecting means changes from the first state into the second state.

20. A control method for an automotive vehicle, comprising the steps of:

detecting an inter-vehicle distance from a host vehicle to a preceding vehicle which is running on a traffic lane at the detected inter-vehicle distance from the host vehicle through an inter-vehicle distance detector;

performing a follow-up running control for the host vehicle such that the host vehicle runs behind the preceding vehicle, maintaining a predetermined inter-vehicle distance to the preceding vehicle; and

generating a vehicular velocity variation inhibit command to maintain a vehicular running state immediately before the inter-vehicle distance detector changes from a first state in which the inter-vehicle distance to the preceding vehicle is being detected into a second state in which the inter-vehicle distance becomes indetectable, and the vehicular velocity variation inhibit command is continued for a duration of time until the host vehicle passes the traffic lane by the inter-vehicle distance immediately before the inter-vehicle distance detector changes from the first state into the second state.