Vehicle spacing control

• US 10,358,131 B2
• Filed: 11/08/2013
• Issued: 07/23/2019
• Est. Priority Date: 11/09/2012
• Status: Active Grant

• Current Assignee: Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno
• Original Assignee: Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno
• Inventors: van Nunen, Ellen, Kester, Leonardus Johannes Hubertus Maria, Ploeg, Jeroen
• Primary Examiner(s): Pham, Ly D
• Application Number:
  US14/441,702
• Publication Number:
  US 20150291162A1
• Time in Patent Office: 2,083 Days
• Field of Search: 702158
• CPC Class Codes: B60W 2554/4041 Position
• CPC Class Codes: B60W 2554/801 Lateral distance
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
• CPC Class Codes: G01B 21/16 for measuring distance of clearance between spaced objects
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9316 combined with communication equipment with other vehicles or with base stations
• 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 2013/9325 for inter-vehicle distance regulation, e.g. navigating in platoons
• CPC Class Codes: G01S 2013/93271 in the front of the vehicles
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes

Abstract

A method of determining a safe distance (d_safe) between a first vehicle (1) and a second vehicle (2) moving ahead of the first vehicle, each vehicle having a state which comprises at least one of a position (s₁, s₂), a speed and an acceleration of the respective vehicle, the method comprising the steps of: —collecting sensor data relating to the state of the vehicles (1, 2), —determining, using the sensor data and a time-dependent description of the state of the second vehicle (2), a state of the second vehicle (2) as a result of a maximum deceleration of said second vehicle, —determining, using a time-dependent model of the behavior of the first vehicle (1) and said state of the second vehicle (2), a state of the first vehicle (1) as a result of said maximum deceleration of said second vehicle (2), and —determining, using said state of the second vehicle (2) and said state of the first vehicle (1), the safe distance (d_safe). Said state of the second vehicle (2) and said state of the first vehicle (1) involve uncertainties introduced by the sensor data, thus increasing the safety margin of the method.

Claims

1. A vehicle distance control method, executed by a vehicle control system, the method comprising determining a safe distance (d_safe) between a first vehicle and a second vehicle moving ahead of the first vehicle, each vehicle having a state which comprises a position (s₁, s₂), a speed (v₁, v₂) and an acceleration (a₁, a₂) of the vehicle, the method comprising the steps of:

the vehicle control system collecting sensor data relating to the states of the vehicles,

the vehicle control system determining, using the sensor data and a time-dependent description of the state of the second vehicle, a computed state of the second vehicle which results from using a maximum deceleration value for said second vehicle,

the vehicle control system determining, using a time-dependent model of the behavior of the first vehicle and said computed state of the second vehicle, a computed state of the first vehicle which results from using said maximum deceleration value for said second vehicle, and

the vehicle control system determining, using said computed state of the second vehicle and said computed state of the first vehicle, the safe distance (d_safe),

the vehicle control system activating a brake of the first vehicle for controlling a speed of the first vehicle on the basis of the safe distance if an actual distance is smaller than the safe distance, wherein the safe distance is determined repeatedly in real time, using said sensor data for said position (s₂), speed (v₂) and acceleration (a₂) of said second vehicle, and wherein one or more of s₂, v₂, and a₂ is evaluated, in determining d_safe, based on its actual value and additionally accounting for

uncertainties introduced into the sensor data by measurement errors of the sensors, communication delays and/or communication losses.

2. The method according to claim 1, wherein the uncertainties are modeled by the standard deviation (sigma) of the respective data, preferably three times the standard deviation (sigma).

3. The method according to claim 1, wherein sensor data for the position, speed and/or acceleration lowered by the uncertainties are substituted in said determining of the computed state of the second vehicle.

4. The method according to claim 1, wherein the uncertainties are modeled using joint probability density functions.

5. The method according to claim 1, wherein the model comprises a temporal convolution product of a temporal transfer function of the first vehicle and the computed state of the second vehicle as a function of time.

6. The method according to claim 1, wherein the sensor data comprise speed data, acceleration data and distance data, the distance data preferably being derived from position data, and wherein the speed data, acceleration data and distance data preferably have a speed data standard deviation (sigma_s), an acceleration data standard deviation (sigma_a) and a distance data standard deviation (sigma_d) respectively.

7. The method according to claim 1, wherein the safe distance (d_safe) is used to determine a safe value of the headway time (h_safe), the headway time being defined as the time it will take for the second vehicle to cover a distance from the tip of the second vehicle to the tip of the first vehicle, which safe value of the headway time is used to adjust a desired headway time (h_des) if the desired headway time is greater than the safe value of the headway time.

8. The method according to claim 1, wherein the safe distance (d_safe) is determined at least once a second.

9. The method according to claim 1, used in a cooperative adaptive cruise control system.

10. A computer program product for carrying out the method according to claim 1.

11. The method according to claim 1, wherein the uncertainties are modeled by the standard deviation (sigma) of the respective data, preferably three times the standard deviation (sigma).

12. The method according to claim 1, wherein sensor data for the position, speed and/or acceleration lowered by the uncertainties are substituted in said determining of the computed state of the second vehicle.

13. The method according to claim 1, wherein the uncertainties are modeled using joint probability density functions.

14. A speed control unit for controlling the speed of a first vehicle in dependence of a second vehicle moving ahead of the first vehicle, each vehicle having a state which comprises a position (s₁, s₂), a speed and an acceleration of the vehicle,

the speed control unit being arranged for receiving sensor data relating to the states of the vehicles from a sensor unit mounted in the first vehicle,

the speed control unit comprising a memory and a processor for storing and processing said sensor data and a model of the vehicle'"'"'s behavior, the speed control unit being arranged for:

determining, using the sensor data and a time-dependent description of the state of the second vehicle, a computed state of the second vehicle which results from using a maximum deceleration value for said second vehicle,

determining, using a time-dependent model of the behavior of the first vehicle and said computed state of the second vehicle, a computed state of the first vehicle which results from using said maximum deceleration value for said second vehicle, and

determining, using said computed state of the second vehicle and said computed state of the first vehicle, the safe distance (d_safe),

the speed control unit activating a brake of the first vehicle for controlling a speed of the first vehicle on the basis of the safe distance if an actual distance is smaller than the safe distance, wherein the safe distance is determined repeatedly in real time, using said sensor data for said position (s₂) of said second vehicle, and wherein s₂ is evaluated, in determining d_safe, based on its actual value and additionally accounting for

uncertainties introduced into the sensor data by measurement errors of the sensors, communication delays and/or communication losses.

15. The speed control unit according to claim 14, wherein the uncertainties are modelled by the standard deviation (sigma) of the respective data, preferably three times the standard deviation (sigma).

16. The method according to claim 14, wherein the uncertainties are modelled using joint probability density functions.

17. The speed control unit according to claim 14, which speed control unit is an adaptive speed control unit, preferably suitable for use in a cooperative adaptive cruise control system.

18. A system for vehicle control, comprising a speed control unit according to claim 14.

19. A vehicle distance control method, executed by a vehicle control system, the method comprising determining a safe distance (d_safe) between a first vehicle and a second vehicle moving ahead of the first vehicle, each vehicle having a state which comprises a position (s₁, s₂), a speed (v₁, v₂) and an acceleration (a₁, a₂) of the vehicle, the method comprising the steps of:

the vehicle control system collecting sensor data relating to the states of the vehicles,

the vehicle control system determining, using the sensor data and a time-dependent description of the state of the second vehicle, a computed state of the second vehicle which results from using a maximum deceleration value for said second vehicle,

the vehicle control system determining, using a time-dependent model of the behavior of the first vehicle and said computed state of the second vehicle, a computed state of the first vehicle which results from using said maximum deceleration value for said second vehicle, and

the vehicle control system determining, using said computed state of the second vehicle and said computed state of the first vehicle, the safe distance (d_safe),

the vehicle control system activating a brake of the first vehicle on the basis of the safe distance if an actual distance is smaller than the safe distance,

wherein said computed state of the second vehicle and said computed state of the first vehicle involve uncertainties introduced into the sensor data by measurement errors of the sensors, communication delays and/or communication losses.

20. A speed control unit for controlling the speed of a first vehicle in dependence of a second vehicle moving ahead of the first vehicle, each vehicle having a state which comprises a position (s₁, s₂), a speed and an acceleration of the vehicle,

the speed control unit being arranged for receiving sensor data relating to the states of the vehicles from a sensor unit mounted in the first vehicle,

the speed control unit comprising a memory and a processor for storing and processing said sensor data and a model of the vehicle'"'"'s behavior, the speed control unit being arranged for:

determining, using the sensor data and a time-dependent description of the state of the second vehicle, a computed state of the second vehicle which results from using a maximum deceleration value for said second vehicle,

determining, using a time-dependent model of the behavior of the first vehicle and said computed state of the second vehicle, a computed state of the first vehicle which results from using said maximum deceleration value for said second vehicle, and

determining, using said computed state of the second vehicle and said computed state of the first vehicle, the safe distance (d_safe),

the speed control unit activating a brake of the first vehicle on the basis of the safe distance if an actual distance is smaller than the safe distance,

wherein said computed state of the second vehicle and said computed state of the first vehicle involve uncertainties introduced into the sensor data by measurement errors of the sensors, communication delays and/or communication losses.