Vehicle sensor cleaning system with laminar flow
Disclosed herein are system, method, and computer program product embodiments for cleaning one or more sensors of a self-driving system (SDS). For example, the SDS is provided with a sensor with a lens that is formed with a convex outer surface. A nozzle is formed with an opening to provide a liquid in a stream at a fan angle relative to a spray axis. The nozzle is spaced apart from the sensor at a distance based on a radius of the lens and the fan angle and configured to spray the liquid with laminar flow onto a proximal end of the lens such that the liquid flows across the lens from the proximal end to a distal end of the lens to remove debris.
1 . A self-driving system (SDS) comprising: a vehicle; a sensor with a lens formed with a convex outer surface; and a nozzle formed with an opening to provide a liquid in a stream at a fan angle relative to a spray axis; wherein the nozzle is spaced apart from the sensor at a distance based on a radius of the lens and the fan angle such that the nozzle is configured to spray the liquid with laminar flow onto a proximal end of the lens such that the liquid flows from the proximal end to a distal end of the lens to remove debris.
2 . The SDS of claim 1 , wherein the fan angle is between twenty-five and sixty-five degrees.
3 . The SDS of claim 1 , wherein the nozzle is configured to mount at a spray angle between the spray axis and a plane that extends tangentially from the lens to direct the spray axis toward the proximal end of the lens.
4 . The SDS of claim 3 , wherein the spray angle is between negative five and positive five degrees.
5 . The SDS of claim 1 , further comprising:
a reservoir to store the liquid;
an actuator to enable and disable liquid communication from the reservoir to the nozzle; and
a controller programmed to control the actuator to enable the liquid communication to the nozzle at a predetermined flow rate for a predetermined period of time to spray the liquid with laminar flow.
6 . The SDS of claim 5 , wherein the predetermined flow rate is between 300 and 600 milliliters per minute, and wherein the predetermined period of time is between 0.5 and 1.2 seconds.
7 . The SDS of claim 5 , further comprising:
a pump to increase a pressure of the liquid within the reservoir; and
wherein the controller is further programmed to control the pump to increase the pressure of the liquid above a threshold pressure.
8 . The SDS of claim 7 , wherein the threshold pressure at the nozzle is between fifty and ninety pounds per square inch.
9 . The SDS of claim 1 , wherein the sensor comprises a camera and wherein the lens is formed in a semi-spherical shape,
wherein the fan angle is between twenty-five and sixty-five degrees, and
wherein the nozzle is configured to mount at a spray angle between the spray axis and a plane that extends tangentially from the lens, the spray angle being between negative five and positive five degrees.
10 . The SDS of claim 1 , wherein the sensor comprises a lidar sensor and wherein the lens is formed in a cylindrical shape, and wherein the nozzle comprises at least three nozzles circumferentially spaced apart from each other around the lens,
wherein the fan angle is between forty and sixty-five degrees, and
wherein the nozzle is configured to mount at a spray angle between the spray axis and a plane that extends tangentially from the lens, the spray angle being between five and twenty degrees.
11 . The SDS of claim 1 , wherein the sensor comprises a lidar sensor and wherein the lens is formed in a cylindrical shape.
12 . The SDS of claim 11 , wherein at least one of the nozzle and the lens rotates relative to the other of the nozzle and the lens to clean the lens with the nozzle.
13 . A self-driving system (SDS) comprising: a vehicle; a sensor with a lens formed with a convex outer surface; and a nozzle formed with an opening to provide a liquid in a stream at a fan angle relative to a spray axis; wherein the nozzle is spaced apart from the sensor at a distance based on a radius of the lens and the fan angle such that the nozzle is configured to spray the liquid with laminar flow characterized by a Reynolds number below 2300 onto a proximal end of the lens such that the liquid flows from the proximal end to a distal end of the lens to remove debris.
14 . The SDS of claim 13 , wherein the fan angle is between twenty-five and sixty-five degrees.
15 . The SDS of claim 13 , wherein the nozzle is configured to mount at a spray angle between the spray axis and a plane that extends tangentially from the lens to direct the spray axis toward the proximal end of the lens.
16 . The SDS of claim 15 , wherein the spray angle is between negative five and positive five degrees.
17 . The SDS of claim 13 , further comprising:
a reservoir to store the liquid;
an actuator to enable and disable liquid communication from the reservoir to the nozzle; and
a controller programmed to control the actuator to enable the liquid communication to the nozzle at a predetermined flow rate for a predetermined period of time to spray the liquid with laminar flow.
18 . The SDS of claim 17 , wherein the predetermined flow rate is between 300 and 600 milliliters per minute, and wherein the predetermined period of time is between 0.5 and 1.2 seconds.
19 . The SDS of claim 17 , further comprising:
a pump to increase a pressure of the liquid within the reservoir; and
wherein the controller is further programmed to control the pump to increase the pressure of the liquid above a threshold pressure.
20 . A self-driving system (SDS) comprising: a vehicle; a sensor with a lens formed with a convex outer surface; and a nozzle formed with an opening to provide a liquid in a stream at a fan angle relative to a spray axis; wherein the nozzle is spaced apart from the sensor at a distance based on a radius of the lens and the fan angle calculated by r * sin{circumflex over ( )}1(θ/2), where r is the radius of the lens and θ is the fan angle such that the nozzle is configured to spray the liquid with laminar flow onto a proximal end of the lens such that the liquid flows along the convex outer surface in laminar flow from the proximal end toward a distal end of the lens to remove debris.