METHOD FOR BRAKING A TRACTOR-TRAILER

1 . A method of braking a tractor-trailer driven autonomously, the method comprising:

sensing, autonomously, a braking event, the braking event being indicative of a requirement for braking the tractor-trailer; and

actuating a trailer brake valve of a trailer of the tractor-trailer to apply trailer brakes in response to the sensing of the braking event, wherein the trailer brakes are applied prior to actuating a tractor brake valve of a tractor of the tractor-trailer to apply tractor brakes and to apply trailer brakes.

2 . The method of claim 1 , wherein the tractor brake valve comprises a first brake valve associated with forward brakes of the tractor, a second brake valve associated with rear brakes of the tractor, and a tractor protection valve associated with the trailer brakes.

3 . The method of claim 2 , wherein the trailer brakes are actuated prior to each of the first brake valve and the second brake valve.

4 . The method of claim 2 , wherein the trailer brake valve is downstream of the tractor protection valve.

5 . The method of claim 2 , wherein the trailer brake valve is upstream of the tractor protection valve.

6 . The method of claim 1 , wherein actuating the trailer brake valve is based on a surface condition of a road.

7 . The method of claim 6 , wherein the surface condition is available traction on the road.

8 . The method of claim 6 , further comprising adjusting a time period that the trailer brake valve is actuated prior to the tractor brake valve based on the surface condition.

9 . The method of claim 6 , further comprising adjusting a pressure through the trailer brake valve based on the surface condition.

10 . The method of claim 1 , further comprising detecting a braking pressure of each of the trailer brake valve and the tractor brake valve.

11 . The method of claim 10 , further comprising determining an accurate braking pressure of the trailer brake valve and the tractor brake valve by employing a voting system for detecting the braking pressure at each of the trailer brake valve and the tractor brake valve.

12 . The method of claim 1 , further comprising detecting a fault in the tractor brake valve or the trailer brake valve.

13 . The method of claim 1 , wherein sensing the braking event further comprises detecting surface conditions and determining a braking operation based on the detected surface conditions.

14 . A method of braking a tractor-trailer, the method comprising:

determining surface conditions of a road;

determining, based on the surface condition, a braking operation of a trailer brake valve; and

actuating the braking operation of the trailer brake valve prior to actuating a tractor brake valve.

15 . The method of claim 14 , wherein determining the braking operation of the trailer brake valve comprises one or both of:

determining a time period of actuation of the trailer brake valve prior to actuation of the tractor brake valve; or

determining a pressure of actuation of the trailer brake valve.

16 . The method of claim 14 , wherein the tractor brake valve comprises a first brake valve associated with forward brakes of a tractor or the tractor-trailer, a second brake valve associated with rear brakes of the tractor, and a tractor protection valve associated with trailer brakes.

17 . The method of claim 16 , wherein the trailer brakes are actuated prior to each of the first brake valve, the second brake valve, and the tractor protection valve.

18 . The method of claim 17 , wherein the trailer brake valve is downstream of the tractor protection valve.

19 . The method of claim 17 , wherein the trailer brake valve is upstream of the tractor protection valve.

20 . The method of claim 14 , wherein the surface condition is available traction on the road.

21 . The method of claim 14 , further comprising detecting a braking pressure of each of the trailer brake valve and the tractor brake valve.

22 . The method of claim 21 , further comprising determining a reliable braking pressure of the trailer brake valve and the tractor brake valve by employing a voting system for detecting the braking pressure at each of the trailer brake valve and the tractor brake valve.

23 . The method of claim 14 , further comprising detecting a fault in the tractor brake valve or the trailer brake valve.

24 . The method of claim 14 , the method further comprising determining that a trailer is coupled to the tractor, wherein the braking operation comprises actuating the trailer brake valve.

25 . The method of claim 14 , the method further comprising determining that a trailer is not coupled to the tractor, wherein the braking operation comprises not actuating the trailer brake valve.