Braking control behaviors for autonomous vehicles
A method and system are provided for controlling braking a vehicle in an autonomous driving mode. For instance, the vehicle is controlled in the autonomous driving mode according to a first braking control mode using a first model to adjust the position of a vehicle relative to an expected position of a current trajectory of the vehicle. Using a second model how close to a maximum deviation threshold the vehicle would come if a maximum braking strength for the vehicle was applied is predicted. The maximum deviation threshold provides an allowed forward deviation from the current trajectory. Based on the prediction, the vehicle is controlled in the autonomous driving mode according to a second braking control mode by automatically applying the maximum braking strength.
1. A method of controlling braking a vehicle in an autonomous driving mode, the method comprising:
controlling, by one or more processors, the vehicle in the autonomous driving mode according to a first braking control mode using a first model to adjust a position of a vehicle relative to an expected position of a current trajectory of the vehicle;
predicting, by the one or more processors, using a second model how close to a maximum deviation threshold the vehicle would come if a maximum braking strength for the vehicle was applied, wherein the maximum deviation threshold is set to provides an allowed forward deviation from the current trajectory; and
based on the prediction, controlling, by the one or more processors, the vehicle in the autonomous driving mode according to a second braking control mode by automatically applying the maximum braking strength.
2. The method of claim 1 , wherein the predicting is further based on a current location of the vehicle, a current acceleration of the vehicle, and a current speed of the vehicle.
3. The method of claim 1 , wherein the predicting is further based on estimated brake performance for the vehicle, acceleration delays, and application rate.
4. The method of claim 1 , wherein the first model is a gain-based model.
5. The method of claim 1 , wherein the maximum braking strength is applied until a deviation value from the current trajectory is zero.
6. The method of claim 1 , wherein the maximum braking strength is applied until a deviation value from the current trajectory is less than zero.
7. The method of claim 1 , wherein the current trajectory is updated over time.
8. The method of claim 1 , further comprising determining that the predicting indicates that the vehicle would meet the maximum deviation threshold, and wherein controlling the vehicle according to the second braking control mode is further based on the determination that the predicting indicates that the vehicle would meet the maximum deviation threshold.
9. The method of claim 1 , further comprising, after controlling the vehicle according to the second braking control mode, controlling the vehicle in the autonomous driving mode according to the first braking control mode.
10. A system for controlling braking a vehicle in an autonomous driving mode, the system comprising:
one or more processors configured to:
control the vehicle in the autonomous driving mode according to a first braking control mode using a first model to adjust the position of a vehicle relative to an expected position of a current trajectory of the vehicle;
predict using a second model how close to a maximum deviation threshold the vehicle would come if a maximum braking strength for the vehicle was applied, wherein the maximum deviation threshold is set to provides an allowed forward deviation from the current trajectory; and
based on the prediction, control the vehicle in the autonomous driving mode according to a second braking control mode by automatically applying the maximum braking strength.
11. The system of claim 10 , further comprising the vehicle.
12. The system of claim 10 , wherein the one or more processors are further configured to predict how close further based on a current location of the vehicle, a current acceleration of the vehicle, and a current speed of the vehicle.
13. The system of claim 10 , wherein the one or more processors are further configured to predict how close further based on estimated brake performance for the vehicle, acceleration delays, and application rate.
14. The system of claim 10 , wherein the first model is a gain-based model.
15. The system of claim 10 , wherein the one or more processors are further configured to apply the maximum braking strength until a deviation value from the current trajectory is zero.
16. The system of claim 10 , wherein the one or more processors are further configured to apply the maximum braking strength until a deviation value from the current trajectory is less than zero.
17. The system of claim 10 , wherein the current trajectory is updated over time.
18. The system of claim 10 , wherein the one or more processors are further configured to determine that the predicting indicates that the vehicle would meet the maximum deviation threshold, and to control the vehicle according to the second braking control mode further based on the determination that the predicting indicates that the vehicle would meet the maximum deviation threshold.
19. The system of claim 10 , wherein the one or more processors are further configured to, after controlling the vehicle according to the second braking control mode, control the vehicle in the autonomous driving mode according to the first braking control mode.
20. A non-transitory computer readable recording medium on which instructions are stored, the instructions, when executed by one or more processors, cause the processors to perform a method of controlling braking a vehicle in an autonomous driving mode, the method comprising:
controlling the vehicle in the autonomous driving mode according to a first braking control mode using a first model to adjust a position of a vehicle relative to an expected position of a current trajectory of the vehicle;
predicting using a second model how close to a maximum deviation threshold the vehicle would come if a maximum braking strength for the vehicle was applied, wherein the maximum deviation threshold is set to provides an allowed forward deviation from the current trajectory; and
based on the prediction, controlling the vehicle in the autonomous driving mode according to a second braking control mode by automatically applying the maximum braking strength.