Vehicle operation based on converging time
Operating a host vehicle is described as including receiving remote vehicle information indicating a geospatial state and a kinematic state for a remote vehicle, identifying host vehicle information indicating a geospatial state and a kinematic state for the host vehicle, determining a converging time to a converging location within a vehicle transportation network based on the remote vehicle information and the host vehicle information, identifying a first threshold at which a fixed deceleration of the host vehicle to the converging location is achieved using a reaction delay of an operator of the host vehicle, wherein the first threshold is a step-wise function based on the kinematic state of the host vehicle, and modifying operation of the host vehicle responsive to the converging time reaching the first threshold. A method, vehicle, and apparatus are described.
1. A method for operating a host vehicle, comprising:
receiving remote vehicle information indicating a geospatial state and a kinematic state for a remote vehicle;
identifying host vehicle information indicating a geospatial state and a kinematic state for the host vehicle;
determining a converging time to a converging location within a vehicle transportation network based on the remote vehicle information and the host vehicle information;
identifying a first threshold at which a fixed deceleration of the host vehicle to the converging location is achieved using a reaction delay of an operator of the host vehicle, wherein the first threshold is a step function based on the kinematic state of the host vehicle; and
modifying operation of the host vehicle responsive to the converging time reaching the first threshold.
2. The method of claim 1 , wherein the first threshold is based on a minimum response time of the operator of the host vehicle, and the minimum response time is a predetermined value.
3. The method of claim 1 , wherein the first threshold is based on a signal propagation delay of the host vehicle.
4. The method of claim 1 , wherein the fixed deceleration is a predetermined value.
5. The method of claim 1 , wherein the fixed deceleration is a learned value based on the host vehicle information gathered during operation by the operator of the host vehicle over time.
6. The method of claim 1 , wherein the reaction delay of the operator is a predetermined value.
7. The method of claim 1 , wherein the reaction delay is a learned value based on the reaction delay of the operator of the host vehicle over time.
8. The method of claim 1 , wherein the first threshold produced by the step function is a fixed value for vehicle speeds below a first speed threshold and increases above the fixed value in a step-wise manner for speeds above the first speed threshold.
9. The method of claim 1 , wherein modifying operation of the host vehicle comprises issuing a warning using at least one of an audio output device or a visual output device.
10. The method of claim 1 , wherein determining a converging time comprises determining a plurality of converging times to the converging location as the host vehicle and the remote vehicle traverse the vehicle transportation network, the method further comprising:
identifying a second threshold at which the fixed deceleration of the host vehicle to the converging location is achieved using the reaction delay of the operator of the host vehicle, the second threshold being a function of the first threshold; and
modifying operation of the host vehicle responsive to the converging time reaching the second threshold.
11. The method of claim 10 , wherein the second threshold TTC2 is identified according to an expression:
TTC 2=( TTC 1−ρ)×τ+ρ
wherein
TTC1 is the first threshold identified by the step function;
τ is a multiplicative factor defined by 0<τ≦2; and
ρ is a system signal propagation delay.
12. The method of claim 11 , wherein the step function produces values for the first threshold equivalent to those output according to an expression:
TTC
1
=
TTC
min
2
×
[
TTC
min
-
⌊
V
0
a
b
⌋
-
σ
|
TTC
min
-
⌊
V
0
a
b
⌋
|
+
σ
+
1
]
+
⌊
V
0
a
b
⌋
2
×
[
⌊
V
0
a
b
⌋
-
TTC
min
+
σ
|
⌊
V
0
a
b
⌋
-
TTC
min
|
+
σ
+
1
]
+
t
rd
+
ρ
wherein:
TTC min is a minimum time at which a warning or other operating instruction is issued;
V 0 is a speed of the host vehicle speed at a time the warning or other operating instruction is issued;
a b is the fixed deceleration;
t rd is the reaction delay; and
σ is a value defined by 0<σ<<1.
13. The method of claim 1 , wherein the step function produces values for the first threshold equivalent to those output according to an expression:
TTC
=
TTC
min
2
×
[
TTC
min
-
⌊
V
0
a
b
⌋
-
σ
|
TTC
min
-
⌊
V
0
a
b
⌋
|
+
σ
+
1
]
+
⌊
V
0
a
b
⌋
2
×
[
⌊
V
0
a
b
⌋
-
TTC
min
+
σ
|
⌊
V
0
a
b
⌋
-
TTC
min
|
+
σ
+
1
]
+
t
rd
+
ρ
wherein:
TTC is the first threshold;
TTC min is a minimum time at which a warning or other operating instruction is issued;
V 0 is a speed of the host vehicle at a time the warning or other operating instruction is issued;
a b is the fixed deceleration;
t rd is the reaction delay;
ρ is a system signal propagation delay; and
σ is a value defined by 0<σ<<1.
14. A vehicle, comprising:
a transmission system;
a sensor; and
an operation system to operate the vehicle, the operation system configured to:
receive remote vehicle information indicating a geospatial state and a kinematic state for a remote vehicle;
identify, using the sensor, host vehicle information indicating geospatial state and kinematic state for the vehicle;
determine a converging time to a converging location within a vehicle transportation network based on the remote vehicle information and the host vehicle information;
identify a first threshold at which a fixed deceleration of the vehicle to the converging location is achieved using a reaction delay of an operator of the vehicle, wherein the first threshold is a step function based on the kinematic state of the vehicle; and
modify operation of the vehicle responsive to the converging time reaching the first threshold.
15. The vehicle of claim 14 , wherein the kinematic state of the vehicle comprises a speed of the vehicle, and the operation system is configured to modify operation of the vehicle responsive to the converging time reaching the first threshold by modifying a control signal to the transmission system.
16. The vehicle of claim 14 , further comprising:
an audio output device; and
a visual output device; and wherein the operation system is configured to modify operation of the vehicle by generating a warning using at least one of the audio output device or the visual output device.
17. An apparatus for controlling a host vehicle, comprising:
a processor; and
memory storing instructions that cause the processor to perform a method comprising:
receiving remote vehicle information indicating a geospatial state and a kinematic state for a remote vehicle;
identifying host vehicle information indicating a geospatial state and a kinematic state for the host vehicle;
determining a converging time to a converging location within a vehicle transportation network based on the remote vehicle information and the host vehicle information;
identifying a first threshold at which a fixed deceleration of the host vehicle to the converging location is achieved using a reaction delay of an operator of the host vehicle, wherein the first threshold is a step-wise function based on the kinematic state of the host vehicle and a signal propagation delay of the host vehicle; and
modifying operation of the host vehicle responsive to the converging time reaching the first threshold.
18. The apparatus of claim 17 , wherein determining a converging time comprises determining a plurality of converging times to the converging location as the host vehicle and the remote vehicle traverse the vehicle transportation network, the method further comprising:
identifying a second threshold at which the fixed deceleration of the host vehicle to the converging location is achieved using the reaction delay of the operator of the host vehicle, the second threshold being a function of the first threshold, and the second threshold being lower than the first threshold;
modifying operation of the host vehicle responsive to the converging time reaching the first threshold by signaling a warning perceptible to the operator; and
modifying operation of the host vehicle responsive to the converging time reaching the second threshold by causing deceleration using a braking system of the host vehicle.
19. The apparatus of claim 17 , further comprising:
determining the fixed deceleration based on the host vehicle information gathered during operation by the operator of the host vehicle over time.
20. The apparatus of claim 17 , wherein the first threshold is based on a minimum response time of the operator of the host vehicle and a speed of the host vehicle as the kinematic state of the host vehicle.