METHOD AND SYSTEM FOR COLLISION AVOIDANCE

• US 20080065328A1
• Filed: 09/07/2007
• Published: 03/13/2008
• Est. Priority Date: 09/08/2006
• Status: Abandoned Application

• Current Assignee: Volvo Car Corporation (AB Volvo)
• Original Assignee: Volvo Car Corporation (AB Volvo)
• Inventors: Eidehall, Andreas, Pohl, Jochen
• Application Number:
  US11/851,642
• Publication Number:
  US 20080065328A1
• Time in Patent Office: Days
• US Class Current: 701/301
• CPC Class Codes: B60W 30/095 Predicting travel path or likelihood of collision
• CPC Class Codes: B60W 30/0956 the prediction being responsive to traffic or environmental parameters
• CPC Class Codes: B60W 30/18163 Lane change; Overtaking manoeuvres
• CPC Class Codes: B60W 50/087 where the control system corrects or modifies a request from the driver
• CPC Class Codes: B60W 50/12 Limiting control by the driver depending on vehicle state, e.g. interlocking means for the control input for preventing unsafe operation
• CPC Class Codes: G01S 13/867 Combination of radar systems with cameras
• CPC Class Codes: G01S 13/931 of land vehicles
• CPC Class Codes: G01S 2013/9318 Controlling the steering
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G01S 7/295 Means for transforming co-ordinates or for evaluating data, e.g. using computers
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes
• CPC Class Codes: G08G 1/167 Driving aids for lane monitoring, lane changing, e.g. blind spot detection

Abstract

A method for collision avoidance for a host vehicle includes the following steps; receiving input data relating to a set of objects external to the host vehicle, wherein an object position (r,φ), and an object velocity ({dot over (r)}) are associated with each object by a sensor system arranged on the host vehicle, then estimating future trajectories of each external object, while considering influence by the future trajectories of the other external objects.

Claims

1. ) Method for collision avoidance for a host vehicle (20) comprising the following method steps:

receiving input data relating to a set of objects external to said host vehicle, said objects being positioned within a detecting range of a sensor system arranged on said host vehicle, wherein an object position (r,φ

), and an object velocity ({dot over (r)}) are associated with each object in said set of objects by said sensor system (18), said input data defining a current state of each object,

estimating future trajectories of each external object, while considering influence by the future trajectories of the other external objects;

characterised in that the further method steps are performed;

determining, by use of a lane exit control block, whether the driver is making an attempt to exit a lane;

determining, by use of a future conflict estimator control block, if the future trajectory of the host vehicle is involved in a conflicting event in a neighbouring lane;

applying, by the use of a lane change prevention unit, a torque in the direction against a torque generated by a driver to effect a lane change in the event said future conflict estimator control block detects a conflict event of relevance for the host vehicle in the lane into which the driver attempts to enter.

2. ) A method according to claim 1, characterised in that the method step of estimating future trajectories of each external object, while considering influence by the future trajectories of the other external objects includes the steps of:

associating a plurality of future control input signals with each moving object, where each future control signal will generate together with the current state of each moving object a separate future path in a state update equation,

determining, by the use of a future trajectory estimator, future trajectories for each of the objects, by selecting one of the most probable future paths as the future trajectory,

3. ) A method according to claim 2, characterised in that, for each moving object, the most probable path is selected as the future trajectory.

4. ) A method according to claim 2, characterised in that each of said future control input signals include a one or more dimensional variable.

5. ) A method according to claim 4, characterised in that each of said future control input signal includes the variables acceleration (a) and steering angle (θ

).

6. ) A method according to claim 5, characterised in that each of said future control input signal is constituted by the variables acceleration (a) and steering angle (θ

).

7. ) A method according to claim 4, characterised in that said plurality of future paths for each moving object are generated by, at each step in a plurality of discrete time steps together forming a prediction horizon, selecting a plurality of values of each variable, wherein said values are selected within a predetermined interval.

8. ) A method according to claim 7, characterised in that a probability number is associated with each value of the variable.

9. ) A method according to claim 8, characterised in that an aggregate probability for each future path at the prediction horizon is calculated.

10. ) A method according to claim 7, characterised in that said plurality of values of each variable are selected by random.

11. ) A method according to claim 2 characterised in that any future path generating a conflicting event between the future trajectory paths of at least two objects, will be rejected as improbable future trajectory paths for the objects involved.

12. ) A method according to claim 1, characterised in that in the event a future trajectory of the host vehicle in the current lane is involved in a conflicting event, interception of the lane change prevention unit is prevented such that a torque will not be applied in the direction against a torque generated by a driver to effect a lane change even in the case where said future conflict estimator control block detects a conflict event of relevance for the host vehicle in the lane into which the driver attempts to enter.

13. ) A method according to claim 1, characterised in that said future trajectory estimator determines whether any of these future trajectories will mutually effect each other due to a risk of conflict in between the future trajectories of at least one pair of objects which is arranged to;

and

14. ) A method according to claim 13, characterised in that said future conflict estimator control block furthermore determines if a future trajectory of the host vehicle in a current lane of the host vehicle does not include any conflicting events with external objects and that said on board system for collision avoidance only allows said lane change prevention unit to prevent lane change if no conflicting events with external objects are detected in the current lane of the host vehicle.

15. ) A method according to claim 13, characterised in that an object and road tracking block processes output data from the sensor system in a state estimator which estimates the states of all external objects, the host vehicle and the road geometry.

16. ) A method according to claim 13 characterised in that said future trajectory estimator corrects the future trajectory of an external object in order to avoid a conflict, when a conflict event between two external objects is detected.

17. ) A method according to claim 13 characterised in that said future trajectory estimator determines the locus of the conflicting event and determines whether this conflict event will have an impact of the host vehicle or not.

18. ) An on board system for collision avoidance comprising

a sensor system arranged on a host vehicle, said sensor system being arranged to receive input data relating to a set of objects external to said host vehicle, said objects being positioned within a detecting range of said sensor system, wherein an object position (r,φ

), and an object velocity ({dot over (r)}) are associated with each object in said set of objects, said input data defining a current state of each object; and

a future trajectory estimator arranged for estimating future trajectories of each external object, while considering influence by the future trajectories of the other external objects;

characterised in that the on board system for collision avoidance further includes;

a lane exit control block arranged do determine whether the driver is making an attempt to exit the lane;

a future conflict estimator control block arranged to determine if the future trajectory of the host vehicle is involved in a conflicting event; and

a lane change prevention unit arranged to apply a torque in the direction against a torque generated by a driver to effect a lane change in the event said future conflict estimator control block detects a conflict event of relevance for the host vehicle in the lane into which the driver attempts to enter.

19. ) An on board system for collision avoidance according to claim 18, characterised in that said future trajectory estimator is arranged to estimate future trajectories of each external object, while considering influence by the future trajectories of the other external objects by:

associating a plurality of future control input signals with each moving object, where each future control signal will generate together with the current state of each moving object a separate future path in a state update equation,

determining, by the use of a future trajectory estimator, future trajectories for each of the objects, by selecting one of the most probable future paths as the future trajectory,

20. ) An on board system for collision avoidance according to claim 19, characterised in that, for each moving object, the most probable path is selected as the future trajectory.

21. ) An on board system for collision avoidance according to claim 19, characterised in that each of said future control input signal includes a one or more dimensional variable.

22. ) An on board system for collision avoidance according to claim 21, characterised in that each of said future control input signal includes the variables acceleration (a) and steering angle (θ

).

23. ) An on board system for collision avoidance according to claim 22, characterised in that each of said future control input signal is constituted by the variables acceleration (a) and steering angle (θ

).

24. ) An on board system for collision avoidance according to claim 21, characterised in that said plurality of future paths for each moving object are generated by, at each step in a plurality of discrete time steps together forming a prediction horizon, selecting a plurality of values of each variable, wherein said values are selected within a predetermined interval.

25. ) An on board system for collision avoidance according to claim 24, characterised in that a probability number is associated with each value of the variable.

26. ) An on board system for collision avoidance according to claim 25, characterised in that an aggregate probability for each future path at the prediction horizon is calculated.

27. ) An on board system for collision avoidance according to claim 24, characterised in that said plurality of values of each variable are selected by random.

28. ) An on board system for collision avoidance according to claims 19, characterised in that any future path generating a conflicting event between the future trajectory paths of at least two objects, will be rejected as improbable future trajectory paths for the objects involved.

29. ) An on board system for collision avoidance according to claim 18, characterised in that in the event a future trajectory of the host vehicle in the current lane is involved in a conflicting event, interception of the lane change prevention unit is prevented such that a torque will not be applied in the direction against a torque generated by a driver to effect a lane change even in the case where said future conflict estimator control block detects a conflict event of relevance for the host vehicle in the lane into which the driver attempts to enter.

30. ) An on board system for collision avoidance according to claim 18, characterised in that said future trajectory estimator is arranged to determine whether any of these future trajectories will mutually effect each other due to a risk of conflict in between the future trajectories of at least one pair of objects

31. ) An on board system for collision avoidance according to claim 30, characterised in that said future conflict estimator control block is furthermore arranged to determine if a future trajectory of the host vehicle in a current lane of the host vehicle does not include any conflicting events with external objects and that said on board system for collision avoidance is arranged to only allow said lane change prevention unit to prevent lane change if no conflicting events with external objects are detected in the current lane of the host vehicle.

32. ) An on board system for collision avoidance according to claim 30, characterised in that an object and road tracking block is arranged to process output data from the sensor system in a state estimator which estimates the states of all external objects, the host vehicle and the road geometry.

33. ) An on board system for collision avoidance according to claim 30, characterised in that said future trajectory estimator is arranged correct to the future trajectory of an external object in order to avoid a conflict, when a conflict event between two external objects is detected.

34. ) An on board system for collision avoidance according to claim 30, characterised in that said future trajectory estimator is arranged to determine the locus of the conflicting event and to determine whether this conflict event will have an impact of the host vehicle or not.