Prediction of driver intent at intersection
10486707 ยท 2019-11-26
Assignee
Inventors
- IDO ZELMAN (RA'ANANA, IL)
- Upali P. Mudalige (Oakland Township, MI, US)
- Thanura Ranmal Elvitigala (Hershey, PA, US)
Cpc classification
B60W2050/0029
PERFORMING OPERATIONS; TRANSPORTING
B60W2900/00
PERFORMING OPERATIONS; TRANSPORTING
B60W2050/0075
PERFORMING OPERATIONS; TRANSPORTING
G08G1/096758
PHYSICS
G08G1/096725
PHYSICS
B60W30/18154
PERFORMING OPERATIONS; TRANSPORTING
G08G1/166
PHYSICS
G08G1/096783
PHYSICS
B60W2420/403
PERFORMING OPERATIONS; TRANSPORTING
G08G1/096775
PHYSICS
B60W2555/60
PERFORMING OPERATIONS; TRANSPORTING
B60W50/0097
PERFORMING OPERATIONS; TRANSPORTING
B60W2556/50
PERFORMING OPERATIONS; TRANSPORTING
B60W2554/80
PERFORMING OPERATIONS; TRANSPORTING
International classification
B60W50/00
PERFORMING OPERATIONS; TRANSPORTING
G08G1/0967
PHYSICS
Abstract
A system and method for predicting whether a driver of a host vehicle or a remote vehicle intends to make a left or right turn or travel straight through an intersection before the host vehicle or remote vehicle reaches the intersection that relies on a probability model that employs a dynamic Bayesian network. The method includes obtaining a plurality of environmental cues that identify external parameters at or around the intersection, where the environmental cues include position and velocity of the remote vehicle, and obtaining a plurality of host vehicle cues that define operation of the host vehicle. The method then predicts the turning intent of the host vehicle and/or remote vehicle at the intersection using the model based on both the external cues and the vehicle cues using the model. The model can use learned information about previous driver turns at the intersection.
Claims
1. A method for predicting turning intent of a host vehicle when approaching an intersection, said method comprising: obtaining, using object sensors onboard the host vehicle, a plurality of environmental cues that identify external parameters at or around the intersection, said environmental cues including position and velocity of remote vehicles, where the object sensors include one or more of cameras, LIDAR sensors and radar detectors; obtaining, from a vehicle CAN bus and vehicle sensors, a plurality of host vehicle cues that define operation of the host vehicle; obtaining previously learned turning information from when the host vehicle previously passed through the intersection that is obtained by capturing, recording and processing signals related to host vehicle turning maneuvers and remote vehicle turning maneuvers including extracting values for parameters being used to predict the turning intent so as to allow better prediction ability and personalization to a specific driver and to a specific intersection; and predicting, using a controller receiving signals from the object sensors, the CAN bus and the vehicle sensors, the turning intent of the host vehicle at the intersection before the host vehicle reaches the intersection based on both the environmental cues and the vehicle cues, wherein predicting the turning intent of the host vehicle includes predicting the probability that the host vehicle will turn right, the probability that the host vehicle will turn left, and the probability that the host vehicle will travel straight through the intersection.
2. The method according to claim 1 wherein predicting the turning intent of the host vehicle includes using a probability model.
3. The method according to claim 2 wherein predicting the turning intent of the host vehicle includes using a dynamic Bayesian network probability analysis.
4. The method according to claim 1 further comprising predicting a turning intent of one or more remote vehicles at the intersection.
5. The method according to claim 4 wherein predicting the turning intent of remote vehicles includes using the environment cues.
6. The method according to claim 1 further comprising predicting traffic flow in the intersection and providing a probability that the host vehicle will proceed, give right-of-way or stop based on the turning intent of the host vehicle.
7. The method according to claim 6 wherein predicting traffic flow includes processing signals concerning objects surrounding the host vehicle, traffic signs, traffic lights and a map database.
8. The method according to claim 1, wherein predicting the turning intent of the host vehicle includes using the previously learned turning information of the host vehicle at the intersection.
9. The method according to claim 1 wherein obtaining environmental cues include obtaining a distance to the intersection.
10. The method according to claim 1 wherein obtaining host vehicle cues includes obtaining one or more of turn signal activity, host vehicle velocity, host vehicle acceleration, host vehicle yaw rate, host vehicle heading and host vehicle steering/road wheel angle.
11. The method according to claim 1 wherein obtaining environmental cues includes obtaining one or more curvature of a preceding road segment, traffic signs, traffic lights and map branching.
12. The method according to claim 1 wherein obtaining a plurality of environmental cues and a plurality of host vehicle cues includes using information from one or more of a map database, V2X communications, and roadside information units.
13. The method according to claim 1 further comprising using the prediction of the turning intent of the host vehicle in a collision avoidance system.
14. A method for predicting turning intent of a host vehicle or a remote vehicle at or near an intersection, said method comprising: obtaining, using object sensors onboard the host vehicle, a plurality of environmental cues that identify external parameters at or around the intersection, said environmental cues including position and velocity of the remote vehicle, where the object sensors include one or more of cameras, LiDAR sensors and radar detectors; obtaining, from a vehicle CAN bus and vehicle sensors, a plurality of host vehicle cues that define operation of the host vehicle; obtaining information of previous turning maneuvers of the host vehicle at the intersection based on providing previously learned turning information from when the host vehicle previously passed through the intersection that is obtained by capturing, recording and processing signals related to host vehicle turning maneuvers and remote vehicle turning maneuvers including extracting values for parameters being used to predict the turning intent so as to allow better prediction ability and personalization to a specific driver and to a specific intersection; and predicting, using a controller receiving signals from the object sensors, the CAN bus and the vehicle sensors, the turning intent of the host vehicle or the remote vehicle at the intersection using a probability model including a dynamic Bayesian network that uses the environmental cues, the vehicle cues and the previous turning maneuver information, wherein predicting the turning intent of the host vehicle includes predicting the probability that the host vehicle will turn right, the probability that the host vehicle will turn left, and the probability that the host vehicle will travel straight through the intersection.
15. The method according to claim 14 wherein obtaining host vehicle cues includes obtaining one or more of turn signal activity, host vehicle velocity, host vehicle acceleration, host vehicle yaw rate, host vehicle heading and host vehicle steering/road wheel angle.
16. The method according to claim 14 wherein obtaining environmental cues includes obtaining one or more of curvature of a preceding road segment, traffic signs, traffic lights and map branching.
17. The method according to claim 14 further comprising predicting traffic flow in the intersection and providing a probability that the host vehicle will proceed, give right-of-way or stop based on the turning intent of the host vehicle.
18. A method for predicting turning intent of a host vehicle or a remote vehicle at or near an intersection, said method comprising: obtaining a plurality of environmental cues that identify external parameters at or around the intersection, said environmental cues including position and velocity of the remote vehicle, wherein obtaining environmental cues includes obtaining one or more curvature of a preceding road segment, traffic signs, traffic lights and map branching; obtaining a plurality of host vehicle cues that define operation of the host vehicle, wherein obtaining host vehicle cues includes obtaining one or more of turn signal activity, host vehicle velocity, host vehicle acceleration, host vehicle yaw rate, host vehicle heading and host vehicle steering/road wheel angle, and wherein obtaining a plurality of environmental cues and a plurality of host vehicle cues includes using information from one or more of radar sensors, cameras, map database, lidar sensors, V2X communications, roadside information units, and a controller area network (CAN) bus; obtaining information of previous turning maneuvers of the host vehicle at the intersection including providing previously learned turning information from when the host vehicle previously passed through the intersection that is obtained by capturing, recording and processing signals related to host vehicle turning maneuvers and remote vehicle turning maneuvers including extracting values for parameters being used to predict the turning intent so as to allow better prediction ability and personalization to a specific driver and to a specific intersection; and predicting, using a controller receiving signals from the object sensors, the CAN bus and the vehicle sensors, the turning intent of the host vehicle or the remote vehicle at the intersection using a probability model including a dynamic Bayesian network that uses the environmental cues, the vehicle cues and the previous turning maneuver information, wherein predicting the turning intent of the host vehicle includes predicting the probability that the host vehicle will turn right, the probability that the host vehicle will turn left, and the probability that the host vehicle will travel straight through the intersection.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1)
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DETAILED DESCRIPTION OF THE EMBODIMENTS
(7) The following discussion of the embodiments of the invention directed to a system and method for predicting whether a driver of a host vehicle or remote vehicles intends to turn left or right or go straight through an intersection is merely exemplary in nature, and is in no way intended to limit the invention or its applications or uses.
(8) As will be discussed in detail below, the present invention proposes a technique for predicting whether a driver of a host vehicle or remote vehicles intends to turn left or right or travel straight through an intersection as the host vehicle approaches the intersection, where the driver turning intent for turning or going straight is interchangeably referred to herein as turning intent or maneuver intent. The prediction algorithm employs a probability model including a dynamic Bayesian network (DBN) that uses available cues, including environmental cues of things happening around the host vehicle and vehicle cues of host vehicle dynamics. Inputs to the prediction algorithm can be provided by any available source, such as a CAN bus on the host vehicle, digital maps, sensors, V2V and V2X communications systems, cameras on the vehicle, etc.
(9) As is well understood by those skilled in the art, a Bayesian network is a probability graphical model that represents a set of random variables and their conditional dependencies. A dynamic Bayesian network is a Bayesian network that relates variables to each other over adjacent time steps. A generative model is a model that randomly generates observable data values, typically given some hidden parameters, and specifies a joint probability distribution over observation and label sequences. Discriminative models are a class of models used in machine learning for modeling the dependence of an unobserved variable on an observed variable x, and is done by modeling the conditional probability distribution P(y|x), which can be used for predicting y from x. The present invention predicts real time turning intent of a host vehicle or remote vehicles by integrating vehicle sensory data with a learning module that maps intersection schematics and defines the relationships between cues, a probabilistic model that utilizes available cues to predict driver intent, and a threat assessment and decision making module.
(10) It is noted that the discussion herein is specific to vehicle travel direction on the right, where a vehicle making a left turn will cross lanes for oncoming traffic. However, it is stressed that the algorithms and discussion herein equally apply to those countries and roadways where vehicles travel on the left and would cross in front of oncoming traffic when making a right turn. It is also noted that, as will be understood by those skilled in the art, the algorithm parameters described here can be adjusted to suit different driver-selectable configurations, such as aggressive, normal, conservative, etc., to modify the warning/output timing provided by the particular feature. Alternatively, the system can itself adjust these parameters based on the driving style of the driver. Further, the algorithms discussed herein may be applicable for other vehicle maneuvers for other driving scenarios including non-cross-shape geometry intersections.
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(14) A turning intent algorithm uses a probability model to predict the turning intent of the host vehicle 54 and/or the remote vehicles 56 at box 72 based on the mapped remote vehicle information from the box 64, the host vehicle information from the box 62, and previously learned turning information for a particular intersection provided at box 66. The previously learned turning information provided at the box 66 is obtained by processing signals related to each turning maneuver separately and extracts values for the parameters being used by the probability model. The previously learned turning information is provided from when the host vehicle previously passed through the intersection and is obtained by capturing, recording and processing signals related to host vehicle turning maneuvers and remote vehicle turning maneuvers. This allows the model to be trained with a better prediction ability and to personalize the model to a specific driver and to a specific intersection. Further, providing information for a specific driver gives the ability to personalize the algorithm with respect to general driver characteristics or to different driving cultures, such as for different countries. Also, personalizing the model with respect to intersections gives the ability to personalize respect to different types of intersections that may differ in the size, number of lanes, heading directions, etc. It is noted that the learning algorithm at the box 66 has the ability to be turned on or off in that it can be used to inform the driver that active safety features have been engaged at an intersection.
(15) The turning intent algorithm employs a probability model based on a dynamic Bayesian network (DBN) that analyzes the signals related to a vehicle during some time window with respect to the turning maneuver options available for that vehicle and gives a probability of a turn based on those signals, as will be discussed in detail below, where the combination of the probability that the host vehicle 54 or one of the remote vehicles 56 will turn left, turn right or go straight will add up to one. The DBN takes advantage of accumulated information along a time interval and does not calculate probabilities according to information at specific time points separately. Once the predicted turning intent of the host vehicle 54 for turning left P.sup.HV.sup.
(16)
(17) For the equations used in the probability model discussed herein, all relevant signals can be used in the model, but in some cases they will not all be available. This ability is desirable in that the algorithm has the ability to process signals with no modification to the algorithm when only partial information is available. Thus, the algorithm will not fail or stop providing output when certain ones of the signals are not being provided at any particular point in time, although the accuracy of the probability may be reduced. The probability equations determine the probability of the vehicle 54 to perform each of the possible turning maneuvers M given vehicle cues related to the vehicle 54, such as kinematic signals including velocity, acceleration and yaw rate, and environmental cues C.sub.e related to the environment, such as distance to intersection, movement of surrounding objects, traffic light status and traffic sign detection. The model is based on a given set of probability functions that first define a prior vehicle maneuver) P(M.sup.0) at time zero, which is defined to be when the vehicle 54 is a predetermined distance from the intersection and the likelihood probabilities of the vehicle cues C.sub.v at that time. The joint probabilities are calculated from the cues C according to their values as observed over the entire time frame from time zero to time T, which is continuously extended as the vehicle 54 approaches the intersection.
(18) Calculating the joint probability over a time frame can be highly complex and generally depends on the frequency in which the cues C are received. Dynamic programming is used in order to provide the calculations efficiently in real-time by decomposing the joint probability over the time frames into three components, namely, the joint probability over the time frame until time t, the likelihood probability of changing the maneuver intent between time t and time t+1, and the likelihood probability of the cues C being observed only at time t+1. That is, at each time step numbers are used that have already been calculated in the previous time step and added new components that are easy to derive. This technique allows the complexity of the algorithm to be spread evenly between the time in which the algorithm is executed and the time in which the host vehicle 54 enters the intersection. The probability of the maneuver intent is continuously being displayed while the vehicle 54 approaches the intersection. This allows not only the probability to be continuously processed in order to access collision threats, but also to process the derivatives of the calculated probabilities, which can significantly enhance threat assessment abilities, such as by observing that a probability of a turning maneuver M is significantly increasing before it actually crossed a pre-defined threshold.
(19) Based on all of the vehicle cues C.sub.v and environmental cues C.sub.e that are available to the prediction model, the algorithm predicts the probability P that the host vehicle 54 and/or the remote vehicles 56 will turn left M=L at the intersection, will travel straight M=S through the intersection, or will turn right M=R at the intersection as:
P(M|C.sub.v,C.sub.e)f or M=L/S/R.(1)
(20) Further, the algorithm defines the prior and likelihood probability functions:
P(M.sup.0),(2)
P(M.sup.t+1|M.sup.t),(3)
P(C.sub.v.sup.0|M.sup.0,C.sub.e.sup.0),(4)
P(C.sub.v.sup.t+1|M.sup.t+1,C.sub.e.sup.t+1,C.sub.v.sup.t),(5)
as defined by Bayes Law:
P(M|C.sub.v,C.sub.e)=P(M,C.sub.v,C.sub.e)/P(C.sub.v,C.sub.e)P(M,C.sub.v,C.sub.e).(6)
(21) Using dynamic programming, a two time-slice Bayesian network can be defined as:
P.sup.tas P(M.sup.t|M.sup.[0,t1],C.sub.e.sup.[0,t],C.sub.v.sup.[0,t]),(7)
P.sup.t+1=P.sup.t.Math.P(M.sup.t+1|M.sup.t,C.sub.v.sup.tC.sub.e.sup.t+1,C.sub.v.sup.t+1)P.sup.tP(M.sup.t+1|M.sup.t)P(C.sub.v.sup.t+1|M.sup.t+1,C.sub.v.sup.t,C.sub.e.sup.t+1).(8)
(22)
(23) For this example, the prediction of the drivers turning intent for each of turning left, turning right and going straight at the intersection can be defined by the prediction function:
P(M.sub.t+1|M.sub.[0,t],D.sub.[0,t+1],O.sub.[0,t+1],I.sub.[0,t+1],V.sub.[0,t+1],A.sub.[0,t+1],Y.sub.[0,t+1])=P(M.sub.t)P(M.sub.t+1|M.sub.t)P(I.sub.t,M.sub.t+1,D.sub.t+1,O.sub.t+1)P(V.sub.t+1|V.sub.t,M.sub.t+1,D.sub.t+1,O.sub.t+1)P(A.sub.t+1|M.sub.t+1,D.sub.t+1)P(Y.sub.t+1|M.sub.t+1,D.sub.t+1).(9)
(24) A number of conditional probabilities can be employed. One non-limiting example is given below, where P(IV|M,D) is calculated with the normal distribution as:
(25)
where , representing an averaged velocity profile, is modeled by a four-degree polynomial as:
(D)=.sub.i=1.sup.4a.sub.iD.sup.i,(11)
and where:
P(YR=yr|M=m,D=d)N((d),.sub.YR),(12)
where , representing an averaged yaw rate profile, is modeled by an exponent as:
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and where:
P(I=i|M=m,D=d)N((d),.sub.1),(14)
where , representing an averaged turn signal activation profile, is modeled by a logistic function as:
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(29) As will be well understood by those skilled in the art, the several and various steps and processes discussed herein to describe the invention may be referring to operations performed by a computer, a processor or other electronic calculating device that manipulate and/or transform data using electrical phenomenon. Those computers and electronic devices may employ various volatile and/or non-volatile memories including non-transitory computer-readable medium with an executable program stored thereon including various code or executable instructions able to be performed by the computer or processor, where the memory and/or computer-readable medium may include all forms and types of memory and other computer-readable media.
(30) The foregoing discussion discloses and describes merely exemplary embodiments of the present invention. One skilled in the art will readily recognize from such discussion and from the accompanying drawings and claims that various changes, modifications and variations can be made therein without departing from the spirit and scope of the invention as defined in the following claims.