ACTIVE LIGHT SENSORS FOR DETERMINING EXPECTED TRACTION VALUE OF A ROAD SEGMENT
A system and method to control a vehicle, provides for directing light onto a region of a road surface on which the vehicle is moving. A variation in a characteristic of a reflection of the directed light is determined. Accumulated precipitation is detected on at least the region of the road based on the determined variation.
1 . A method for operating a vehicle, the method comprising:
directing light onto a region of a road surface on which the vehicle is moving;
determining, over the region of the road surface, a variation in a characteristic of a reflection of the directed light; and
detecting accumulated precipitation on at least the region of the road surface based on the determined variation.
2 . The method of claim 1 , wherein the signal characteristic includes at least one of an intensity or power of the reflection.
3 . The method of claim 1 , wherein directing light onto the region includes controlling a LiDar device that directs a laser onto the road surface.
4 . The method of claim 3 , wherein detecting accumulated precipitation is performed using a LiDar device that is mounted on the vehicle to detect both accumulated precipitation and objects on the roadway.
5 . The method of claim 1 , further comprising:
classifying the accumulated precipitation based on the variation in the characteristic of the reflection.
6 . The method of claim 5 , wherein classifying the accumulated precipitation includes estimating a coefficient of friction for a portion of the roadway on which the accumulated precipitation is detected.
7 . The method of claim 5 , wherein classifying the accumulated precipitation includes classifying the precipitation as one of snow, ice, or water.
8 . The method of claim 5 , wherein classifying the accumulated precipitation includes determining elevation of accumulated snow on the roadway.
9 . The method of claim 1 , further comprising selecting one or more vehicle operations in response to detecting the accumulated precipitation.
10 . The method of claim 8 , wherein the selected one or more operations includes steering the vehicle to avoid the region of the road surface.
11 . The method of claim 8 , wherein the selected one or more operations includes slowing the vehicle in advance of reaching the region of the vehicle.
12 . The method of claim 1 , further comprising:
estimating a traction value of the region of the roadway based on the detected accumulated precipitation;
measuring, as the vehicle travels over the region of the roadway, one or more sensor values that correlate to the traction value on the roadway; and
comparing the estimated traction value to the traction value that is correlated from the measured one or more sensor values.
13 . The method of claim 12 , wherein estimating the traction value of the region of the roadway includes implementing a model to determine the traction.
14 . The method of claim 13 , further comprising training the model based on comparing the estimated traction value to the traction value that is correlated from the measured one or more sensor values.
15 . A control system for a vehicle, the control system comprising:
a memory to store a set of instructions;
one or more processors to execute instructions stored in memory to;
direct light onto a region of a road surface on which the vehicle is moving;
determine, over the region of the road surface, a variation in a characteristic of a reflection of the directed light; and
detect accumulated precipitation on at least the region of the road surface based on the determined variation.
16 . The control system of claim 15 , wherein the signal characteristic includes at least one of an intensity or power of the reflection.
17 . The control system of claim 15 , wherein the signal characteristic includes at least one of an intensity or power of the reflection.
18 . The control system of claim 15 , wherein directing light onto the region includes controlling a LiDar device that directs a laser onto the road surface.
19 . The control system of claim 15 , further comprising a LiDar to provide the directed light, wherein the processor determines a variation in an intensity or power of a return reflection of the directed light.
20 . The control system of claim 19 , wherein the one or more processors classify the accumulated precipitation based on the return reflection of the directed light from the LiDar.