Apparatus for calculating deflection of central axis of an obstacle detecting apparatus mounted on a vehicle and apparatus for correcting the deflection of central axis, and system for controlling distance to a preceding vehicle traveling ahead

• US 6,246,949 B1
• Filed: 12/27/1996
• Issued: 06/12/2001
• Est. Priority Date: 12/27/1995
• Status: Expired due to Term

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Shirai, Noriaki, Hibino, Katsuhiko, Nishimura, Takao
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): DONNELLY, ARTHUR D
• Application Number:
  US08/780,092
• Time in Patent Office: 1,628 Days
• Field of Search: 701/96, 701/301, 356/28, 342/69, 342/70, 250/208
• US Class Current: 701/96
• CPC Class Codes: B60K 31/0008 including means for detecting potential obstacles in vehicle path
• CPC Class Codes: B60T 2201/08 Lane monitoring; Lane Keeping Systems
• CPC Class Codes: B60T 2201/081 using distance control
• CPC Class Codes: B60W 2050/021 Means for detecting failure or malfunction
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
• CPC Class Codes: B60W 30/18145 Cornering
• CPC Class Codes: G01S 17/931 of land vehicles
• 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
• CPC Class Codes: G01S 2013/9324 Alternative operation using ultrasonic waves
• CPC Class Codes: G01S 7/403 in azimuth, i.e. in the horizontal plane
• CPC Class Codes: G01S 7/4091 during normal radar operation
• CPC Class Codes: G01S 7/4972 Alignment of sensor
• CPC Class Codes: G01S 7/52004 Means for monitoring or calibrating short-range imaging G01S7/5205

Abstract

The present invention aims to facilitate easy correction of the center axis of an obstacle detecting apparatus for a vehicle by calculating deflection of the center axis with respect to the vehicle. Each of most obstacles recognized as moving objects is a preceding vehicle 93, and when the subject vehicle 91 is moving straight, the preceding vehicle 93 is detected in a position straight ahead of the subject vehicle 91. If the optical axis 95 of the transmitting/receiving section 31 is oriented straight ahead of the subject vehicle 91, the preceding vehicle 93 will be detected on the optical axis 95. On the other hand, when the optical axis 95 deviates from the center axis of the vehicle, the preceding vehicle 93 is detected in a position deviated from the optical axis 95 by an angle θ m. In this case, the value θ of deflection of optical axis 95 is equal to −θ m. In addition, by determining whether or not the relative velocity vector component of an obstacle is within a given range, the accuracy of calculation can be bettered with data of vehicles moving in an adjacent lane and data of vehicles moving along a curve being removed.

Claims

1. An apparatus for adjusting a deflection of central axis of an obstacle detecting apparatus mounted on a vehicle and operative to radiate a transmission wave over a given angular range from a given central axis to the width direction of the vehicle and to detect a distance to and an angle of an obstacle in response to a reflected wave from the obstacle, comprising:

object recognizing means for determining whether the obstacle is a stationary object or a moving object on the basis of changes in distance to and angle of the obstacle detected by the obstacle detecting apparatus;

speed calculating means for calculating a vector representing a speed of the obstacle relative to the vehicle;

first deflection calculating means, for when a target obstacle is selected from among obstacles detected by the obstacle detecting apparatus under conditions that the target obstacle has been recognized as a moving object by said object recognizing means and the relative speed thereof calculated by said speed calculating means falls within a given range, calculating the deflection of central axis of the obstacle detecting apparatus relative to the vehicle based upon an angle of the target obstacle; and

deflection adjusting means for adjusting the deflection of central axis of the obstacle detecting apparatus calculated by said deflection calculating means.

2. An apparatus for adjusting a deflection of central axis of an obstacle detecting apparatus mounted on a vehicle and operative to radiate a transmission wave over a given angular range from a given central axis to the width direction of the vehicle and to detect a distance to and an angle of an obstacle in response to a reflected wave from the obstacle, comprising:

object recognizing means for determining whether the obstacle is a stationary object or a moving object on the basis of changes in distance to and angle of the obstacle detected by the obstacle detecting apparatus;

speed calculating means for calculating a vector representing a speed of the obstacle relative to the vehicle;

second deflection calculating mean, for when a target obstacle is selected from among obstacles detected by the obstacle detecting apparatus under conditions that the target obstacle has been recognized as a stationary object by said object recognizing means and the distance thereto detected by the obstacle detecting apparatus is less than a given value, calculating the deflection of central axis of the obstacle detecting apparatus relative to the vehicle based upon the direction of the vector representing the relative speed of the target obstacle calculated by said speed calculating means; and

deflection adjusting means for adjusting the deflection of central axis of the obstacle detecting apparatus calculated by said deflection calculating means.

3. An apparatus for calculating a deflection of central axis of an obstacle detecting apparatus mounted on a vehicle and operative to radiate a transmission wave over a given angular range from a given central axis to a width direction of the vehicle and to detect a distance to and an angle of a target obstacle in response to a reflected wave from the obstacle, the apparatus comprising:

object recognizing means for determining whether the target obstacle is stationary or moving based upon changes in the distance and the angle of the target obstacle detected by the obstacle detecting apparatus;

speed calculating means for calculating a speed of the target obstacle relative to the vehicle;

first deflection calculating means calculating the deflection of central axis of the obstacle detecting apparatus relative to the vehicle on the basis of the angle of the obstacle, calculating when the target obstacle, selected from obstacles detected by the obstacle detecting apparatus, has been determined to be moving and the relative speed of the target obstacle falls within a given range; and

angle correcting means for correcting the angle of the target obstacle detected by the obstacle detecting apparatus based upon the calculated deflection.

7. An apparatus as set forth in claim 3 or 4 or 5 further comprising third deflection calculating means, when a target obstacle is selected from among obstacles detected by the obstacle detecting apparatus under a condition that the target obstacle has been recognized as a stationary object by said object recognizing means, which calculates the deflection of central axis of the obstacle detecting apparatus relative to the vehicle on the basis of the direction of the vector representing the relative speed of the target obstacle calculated by said speed calculating means.

8. An apparatus as set forth in claim 3 or 5, wherein when a target obstacle is selected, from among obstacles continuously detected for a given time period or more by the obstacle detecting apparatus, under conditions the target obstacle has been recognized as a moving object by said object recognizing means and the components of the vector representing the relative speed thereof calculated by said speed calculating means falls within a given range, said first deflection calculating means calculates the deflection of central axis of the obstacle detecting apparatus relative to the vehicle on the basis of the angle of the target obstacle detecting by the obstacle detecting apparatus.

9. An apparatus as set forth in claim 3 or 5, the apparatus further comprising width calculating means for calculating a width of an obstacle on the basis of the distance to and angle of the obstacle detected by the obstacle detecting apparatus, wherein when a target obstacle is selected from among obstacles detected by the obstacle detecting apparatus under conditions that the target obstacle has been recognized as a moving object by said object recognizing means, the components of the vector representing the relative speed thereof calculated by said speed calculating means falls within a given range, and the width thereof calculated by said width calculating means falls within a given range, said first deflection calculating means calculates the deflection of central axis of the obstacle detecting apparatus relative to the vehicle on the basis of the angle of the target obstacle detected by the obstacle detecting apparatus.

10. An apparatus as set forth in claim 3 or 5, the apparatus further comprising:

average value calculating means for calculating a mean or average value of a plurality of deflections of central axis each of which is individually calculated as a result of plural calculation cycles of said first deflection calculating means;

standard deviation calculating means for calculating a standard deviation of the plurality of deflections; and

a deflection evaluating means for evaluating the average value of the plurality of deflections to be a reliable value for the deflection of central axis of the obstacle detecting apparatus relative to the vehicle when the standard deviation is smaller than a given value and the number of deflections upon which the average value and the standard deviation are calculated is a given number or more, or for evaluating the value of each deflection and the average value of the plurality of deflections to be unreliable values when the standard deviation is the given value or larger and the number of deflections is less than the given number.

12. An apparatus for calculating a deflection of central axis of an obstacle detecting apparatus for a vehicle, which includes both said first deflection calculating means and said third deflection calculating means as set forth in claim 7, wherein when an absolute value of the deflection calculated by said third deflection calculating means is a given value or larger, the value of the deflection calculated by said first deflection calculating means is neglected.

13. An apparatus as set forth in claim 7, the apparatus further comprising straight advancement determining means for determining whether or not the vehicle is traveling straight, wherein said first, second or third deflection calculating means calculates the deflection only when said straight advancement determining means determines that the vehicle is traveling straight.

14. An apparatus as set forth in claim 3 or 4, the obstacle detecting apparatus comprising:

transmitting means for radiating a transmission wave every given angle in a scanning manner;

receiving means for receiving a reflected wave from an obstacle;

distance calculating means for calculating a distance to the obstacle on the basis of an interval of time between the moment of transmission of the transmission wave by said transmitting means and the moment of reception of the reflected wave by said receiving means; and

storage means for storing data representing the distance to the obstacle provided by said distance calculating means with maintaining the one-to-one correspondence between the distance to the obstacle and the angle of radiation at which the corresponding transmission wave is radiated, such that said angle correcting means corrects the angle of the obstacle relative to the vehicle by changing the correspondence or the relation between the distance to the obstacle and the angle of radiation stored in said storage means.

15. An apparatus as set forth in claim 3 or 4, the apparatus further comprising coordinate transforming means for transforming the distance to and angle of the obstacle detected by the obstacle detecting apparatus into a position of orthogonal coordinates by solving a given equation for coordinate transformation, such that the angle correcting means corrects the angle of the obstacle relative to the vehicle by changing or alternating the equation for coordinate transformation provided by said coordinate transformation means.

4. An apparatus for calculating a deflection of central axis of an obstacle detecting apparatus mounted on a vehicle and operative to radiate a transmission wave over a given angular range from a given central axis to a width direction of the vehicle and to detect a distance to and an angle of an obstacle in response to a reflected wave from the obstacle, the apparatus comprising:

object recognizing means for determining whether the obstacle is stationary or moving based upon changes in the distance and the angle of the obstacle detected by the obstacle detecting apparatus;

speed calculating means for calculating a vector representing a speed of the obstacle relative to the vehicle;

second deflection calculating means calculating the deflection of central axis of the obstacle detecting apparatus relative to the vehicle based upon direction of the calculated vector, calculating when the obstacle has been determined to be stationary and the distance thereto detected by the obstacle detecting apparatus is less than a given value; and

angle correcting means for correcting the angle of the obstacle detected by the obstacle detecting apparatus on the basis of the calculated deflection.

11. An apparatus for calculating a deflection of central axis of an obstacle detecting apparatus for a vehicle, which includes either said second deflection calculating means or said third deflection calculating means as set forth in claim 4 or 6, the apparatus further comprising:

average value calculating means for calculating a mean or average value of a plurality of deflections of central axis each of which is individually calculated as a result of plural calculation cycles of said second or third deflection calculating means;

standard deviation calculating means for calculating a standard deviation of the plurality of deflections; and

deflection evaluating means for evaluating the average value of the plurality of deflections to be a reliable value for the deflection of central axis of the obstacle detecting apparatus relative to the vehicle when the standard deviation is smaller than a given value and the number of deflections upon which the average value and the standard deviation are calculated is a given number or more, or for evaluating the value of each deflection and the average value of the plurality of deflections to be unreliable values when the standard deviation is the given value or larger and the number of deflections is less than the given number.

5. An inter-vehicle distance control apparatus including

an obstacle detecting apparatus for a subject vehicle radiating a transmission wave over a given angular range from a given central axis to a width direction of the subject vehicle and to detect a distance to and an angle of an obstacle in response to a reflected wave from the obstacle,

preceding vehicle selecting means for selecting a preceding vehicle from among obstacles detected by said obstacle detecting apparatus, the preceding vehicle corresponding to a target obstacle for which inter-vehicle distance control should be executed, and

inter-vehicle distance control means for controlling speed of the subject vehicle to maintain a distance between the subject vehicle and the preceding vehicle, said inter-vehicle distance control apparatus comprising:

object recognizing means for determining whether the target obstacle is stationary or moving based upon changes in the distance and the angle detected by the obstacle detecting apparatus;

speed calculating means for calculating a speed of the target obstacle relative to the subject vehicle;

first deflection calculating means calculating the deflection of central axis of the obstacle detecting apparatus relative to the vehicle on the basis of the angle of the obstacle, calculating when the target obstacle, selected from obstacles detected by the obstacle detecting apparatus, has been determined to be moving and the relative speed of the target obstacle falls within a given range; and

control condition changing means for changing a control condition of said inter-vehicle distance control means based upon the calculated deflection.

16. An inter-vehicle distance control system as set forth in claim 5 or 6, wherein said control condition changing means changes the value of acceleration/deceleration of the subject vehicle to be adjusted by said inter-vehicle distance control means in response to the deflection calculated by said deflection of central axis calculating apparatus.

17. An inter-vehicle distance control system as set forth in claim 16, wherein said control condition changing means reduces the value of the acceleration/deceleration of the subject vehicle to be adjusted by said inter-vehicle distance control means in response to the deflection calculated by said deflection of central axis calculating apparatus.

18. An inter-vehicle distance control system as set forth in claim 5 or 6, wherein said control condition changing means stops the control processing to be executed by said inter-vehicle distance control means in response to the value of the deflection calculated by said deflection of central axis calculating apparatus.

19. An inter-vehicle distance control system as set forth in claim 18, further comprising sudden-change detecting means for detecting a sudden change in deflection of central axis of said obstacle detecting apparatus, such that said control condition changing means stops the control processing to be executed by said inter-vehicle distance control means when a sudden change in deflection of central axis of said obstacle detecting apparatus is detected by said sudden-change detecting means.

6. An inter-vehicle distance control apparatus including

an obstacle detecting apparatus for a subject vehicle radiating a transmission wave over a given angular range from a given central axis to a width direction of the subject vehicle and to detect a distance to and an angle of an obstacle in response to a reflected wave from the obstacle,

preceding vehicle selecting means for selecting a preceding vehicle from among obstacles detected by said obstacle detecting apparatus, the preceding vehicle corresponding to a target obstacle for which inter-vehicle distance control should be executed, and

inter-vehicle distance control means for controlling speed of the subject vehicle to maintain a distance between the subject vehicle and the preceding vehicle, said inter-vehicle distance control apparatus comprising:

object recognizing means for determining whether the target obstacle is stationary or moving based upon changes in the distance and the angle detected by the obstacle detecting apparatus;

speed calculating means for calculating a vector representing a speed of the obstacle relative to the vehicle;

second deflection calculating means calculating the deflection of central axis of the target obstacle detecting apparatus relative to the vehicle based upon direction of the calculated vector, calculating when the obstacle has been determined to be stationary and the distance thereto detected by the obstacle detecting apparatus is less than a given value; and

control condition changing means for changing a control condition of said inter-vehicle distance control means based upon the calculated deflection.