Park brake system and method for corroborated pressure reporting
A park brake system and method for corroborated pressure reporting are provided. In one example implementation, primary and redundant park brake controllers read their respecting pressure sensors along an air channel to a parking brake. The controllers exchange the sensor readings, and each controller determines whether or not the sensor readings are in agreement. The controllers provide their determinations to an automated driving system. If the sensor readings are not in agreement, the automated driving system can partially or completely disengage or take some other action. Other implementations are provided.
1 . A park brake system comprising:
a first park brake controller configured to receive a first pressure sensor reading from a first pressure sensor in a vehicle; and
a second park brake controller configured to receive a second pressure sensor reading from a second pressure sensor in the vehicle;
wherein:
the first park brake controller is further configured to receive the second pressure sensor reading from the second park brake controller;
the second park brake controller is further configured to receive the first pressure sensor reading from the first park brake controller;
each of the first and second park brake controllers is further configured to compare the first and second pressure sensor readings and transmit a result of the comparing to an automated driving system of the vehicle;
the automated driving system of the vehicle is configured to operate in a first mode in response to the first and second pressure sensor readings being in agreement;
the automated driving system of the vehicle is configured to operate in a second mode in response to the first and second pressure sensor readings not being in agreement.
2 . The park brake system of claim 1 , wherein the first and second pressure sensors are along an air flow to one of a tractor park brake and a trailer park brake.
3 . The park brake system of claim 2 , further comprising an additional set of pressure sensors along an air flow to the other one of the tractor park brake and a trailer park brake.
4 . The park brake system of claim 1 , wherein the first and second park brake controllers are in a single brake circuit.
5 . The park brake system of claim 1 , wherein the automated driving system is configured to perform one or more of the following in response to receiving the result: determine whether to start a driving mission, determine whether to detour the vehicle for servicing, determine whether to require a human driver to operate the vehicle, and determine whether to verify a park status of the vehicle.
6 . The park brake system of claim 1 , wherein each of the first and second park brake controllers is further configured to transmit its associated pressure sensor reading to the automated driving system in response to failing to receive a pressure sensor reading from the other one of the first and second park brake controllers.
7 . The park brake system of claim 6 , wherein the automated driving system is configured to a take different action depending on which one of the first and second park brake controllers failed to report its pressure sensor reading.
8 . The park brake system of claim 1 , wherein the result indicates a match in response to the first and second pressure sensor readings being within a tolerance level.
9 . The park brake system of claim 8 , wherein the tolerance level is about 5%.
10 . The park brake system of claim 1 , wherein the result indicates one of the following: disagreement on vehicle status, agreement on trailer charged status, agreement on trailer exhausted status, agreement on truck charged status, agreement on truck exhausted status, and agreement on no trailer present.
11 . The park brake system of claim 1 , wherein the first and second park brake controllers are further configured to communicate with each other and the automated driving system via a controller area network (CAN).
12 . A method comprising:
performing in a vehicle comprising a park brake, pressure sensors along an air channel to the park brake, and at least one virtual driver:
determining whether readings from the pressure sensors are in agreement;
in response to determining that the readings from the pressure sensors are in agreement, causing the at least one virtual driver to operate in a first mode; and
in response to determining that the readings from the pressure sensors are not in agreement, causing the at least one virtual driver to operate in a second mode.
13 . The method of claim 12 , wherein the determining is performed by primary and redundant park brake controllers.
14 . The method of claim 13 , further comprising informing the at least one virtual driver when only one of the primary and redundant park brake controllers is reporting its pressure sensor reading.
15 . The method of claim 13 , wherein the first and second park brake controllers are in a single brake circuit.
16 . The method of claim 12 , wherein the park brake comprises one of a tractor park brake and a trailer park brake, and wherein the method is repeated for the other one of the tractor park brake and the trailer park brake.
17 . The method of claim 12 , wherein, in the first mode, the at least one virtual driver is in a fully-autonomous state.
18 . The method of claim 12 , wherein, in the second mode, the at least one virtual driver is configured to perform one or more of: detouring the vehicle for servicing, requiring a human driver to operate the vehicle, and verifying a park status of the vehicle.
19 . The method of claim 12 , further comprising reporting one or more of following to the at least one virtual driver: disagreement on vehicle status, agreement on trailer charged status, agreement on trailer exhausted status, agreement on truck charged status, agreement on truck exhausted status, and agreement on no trailer present.
20 . A park brake system comprising:
means for detecting a pressure difference in a flow of air to a park brake of a vehicle by determining whether pressure sensor readings are in agreement; and
means for informing an automated driving system of the vehicle of the detected pressure difference, wherein the detected pressure difference prevents the automated driving system from engaging in a fully-autonomous mode.
21 . The park brake system of claim 20 , further comprising a primary electronic parking brake and a redundant electronic control unit, wherein the means for detecting and the means for informing are in both the primary electronic parking brake and the redundant electronic control unit.