Patent Publication Number: US-2022236382-A1

Title: Rotating sensor assembly

Description:
BACKGROUND 
     Vehicles, such as autonomous or semi-autonomous vehicles, typically include a variety of sensors. Some sensors detect internal states of the vehicle, for example, wheel speed, wheel orientation, and engine and transmission variables. Some sensors detect the position or orientation of the vehicle, for example, global positioning system (GPS) sensors; accelerometers such as piezo-electric or microelectromechanical systems (MEMS); gyroscopes such as rate, ring laser, or fiber-optic gyroscopes; inertial measurements units (IMU); and magnetometers. Some sensors detect the external world, for example, radar sensors, scanning laser range finders, light detection and ranging (LIDAR) devices, and image processing sensors such as cameras. A LIDAR device detects distances to objects by emitting laser pulses and measuring the time of flight for the pulse to travel to the object and back. Some sensors are communications devices, for example, vehicle-to-infrastructure (V2I) or vehicle-to-vehicle (V2V) devices. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an example vehicle including an example sensor assembly. 
         FIG. 2  is a perspective of the sensor assembly. 
         FIG. 3  is a top cross-sectional view of the sensor assembly. 
     
    
    
     DETAILED DESCRIPTION 
     A sensor assembly includes a base, a housing mounted to the base and rotatable relative to the base around an axis in a direction of rotation, a sensing apparatus inside the housing and rotatable with the housing, and a sensor window extending from a point on the housing in a direction that is radially outward and circumferential relative to the axis. The sensor window is flat. The sensing apparatus has a field of view through the sensor window. An exterior surface of the sensor window faces in a direction that is radially outward and circumferentially in the direction of rotation relative to the axis. 
     The sensor assembly may further include a motor arranged to rotate the housing in the direction of rotation relative to the base. 
     The housing may include an outer wall having a partial cylindrical shape extending circumferentially at a constant outer radius from the axis. The outer wall may extend circumferentially around the axis for at least 90°. 
     The sensor window may be disposed farther from the axis than the outer radius of the outer wall. 
     The sensor window may extend from a point nearest the outer wall in the direction that is radially outward and circumferential relative to the axis. The housing may include a window wall, the window wall may have an opening in which the sensor window is positioned, the window wall may be flat and parallel to the sensor window, and the window wall may border the outer wall. The window wall may extend in a direction tangent to the outer wall. 
     The sensor window may be recessed in the window wall. 
     The housing may include a nonwindow wall, the nonwindow wall may border the window wall, and an exterior surface of the nonwindow wall may face in a direction that is radially outward and circumferentially away from the direction of rotation relative to the axis. The outer wall, the window wall, and the nonwindow wall may have a constant cross-section along the axis from a bottom of the sensor window to a top of the sensor window. 
     The outer wall, the window wall, and the nonwindow wall may collectively extend 180° around the axis. The sensor window may be a first sensor window, the outer wall may be a first outer wall, the window wall may be a first window wall, the nonwindow wall may be a first nonwindow wall, and the housing may include a second outer wall, a second window wall, and a second nonwindow wall that are rotationally symmetric by 180° around the axis with respect to the first outer wall, the first window wall, and the first nonwindow wall. 
     The sensor window may extend circumferentially around the axis for at most 45°. 
     The sensor window may be rectangular. 
     The sensor window may be one of at least one sensor window, and the at least one sensor window may collectively extend circumferentially around the axis for at most 90°. The at least one sensor window may include two sensor windows, and each of the sensor windows may extend for at most 45°. The two sensor windows may be rotationally symmetric by 180° around the axis with respect to each other. 
     With reference to the Figures, a sensor assembly  102  of a vehicle  100  includes a base  104 , a housing  106  mounted to the base  104  and rotatable relative to the base  104  around an axis A in a direction of rotation D, a first sensing apparatus  108   a  inside the housing  106  and rotatable with the housing  106 , and a first sensor window  110   a  extending from a point on the housing  106  in a direction that is radially outward and circumferential relative to the axis A. The first sensor window  110   a  is flat. The first sensing apparatus  108   a  has a field of view through the first sensor window  110   a . An exterior surface of the first sensor window  110   a  faces in a direction that is radially outward and circumferentially in the direction of rotation D relative to the axis A. 
     The direction of rotation D and the shape and orientation of the first sensor window  110   a  combine to create a lateral airflow across the first sensor window  110   a  that helps to clean the first sensor window  110   a . As the first sensor window  110   a  rotates with the housing  106  in the direction of rotation D, the first sensor window  110   a  sweeps unobstructed through the air, i.e., is on a portion of the sensor assembly  102  that pushes through the air. The first sensor window  110   a  slides past the air surrounding the sensor assembly  102 , creating a lateral airflow across the first sensor window  110   a , and at the same time pushes that air radially outward relative to the axis A, increasing the pressure of the air against the first sensor window  110   a . The airflow relative to the first sensor window  110   a  can help clean debris from the first sensor window  110   a , which can help the first sensing apparatus  108   a  to detect an environment surrounding the vehicle  100 . 
     With reference to  FIG. 1 , the vehicle  100  may be any suitable type of automobile, e.g., a passenger or commercial automobile such as a sedan, a coupe, a truck, a sport utility vehicle, a crossover vehicle, a van, a minivan, a taxi, a bus, etc. The vehicle  100 , for example, may be an autonomous vehicle. In other words, the vehicle  100  may be autonomously operated such that the vehicle  100  may be driven without constant attention from a driver, i.e., the vehicle  100  may be self-driving without human input. Autonomous operation can be based in part on data received from the sensor assembly  102 . 
     The vehicle  100  includes a vehicle body  112 . The vehicle body  112  includes body panels  114  partially defining an exterior of the vehicle  100 . The body panels  114  may present a class-A surface, e.g., a finished surface exposed to view by a customer and free of unaesthetic blemishes and defects. The body panels  114  include, e.g., a roof  116 , etc. 
     A casing  118  for the sensor assembly  102  and other sensors is attachable to the vehicle  100 , e.g., to one of the body panels  114  of the vehicle  100 , e.g., the roof  116 . For example, the casing  118  may be shaped to be attachable to the roof  116 , e.g., may have a shape matching a contour of the roof  116 . The casing  118  may be attached to the roof  116 , which can provide the first sensing apparatus  108   a  and a second sensing apparatus  108   b  of the sensor assembly  102  with an unobstructed field of view of an area around the vehicle  100 . The casing  118  may be formed of, e.g., plastic or metal. The sensor assembly  102  is supported by the casing  118 . The sensor assembly  102  can be disposed on top of the casing  118  at a highest point of the casing  118 . 
     With reference to  FIG. 2 , the sensor assembly  102  includes the base  104 . The base  104  is attached to the casing  118  on top of the casing  118 . The base  104  can be bolted to the casing  118 , e.g., through bolt holes in the base  104 . The base  104  is mounted to the vehicle  100 , e.g., via the casing  118 , and the vehicle  100  defines a forward direction F, i.e., a direction of forward travel for the vehicle  100 . 
     The sensor assembly  102  includes a motor  120 . The motor  120  is arranged to drivably rotate the housing  106  in the direction of rotation D about the axis A. The motor  120  can be positioned, e.g., inside the base  104 . The motor  120  can be, e.g., an electric motor. 
     The housing  106  is mounted to the base  104  and rotatable relative to the base  104  around the axis A in the direction of rotation D. For example, the housing  106  can be mounted, e.g., fastened, to a sensor body (not shown). The sensor body can be rotatably attached to the base  104  and drivable by the motor  120 . The housing  106  can cover a top and sides of the sensor body. 
     The sensing apparatuses  108  are disposed inside the housing  106  and are rotatable with the housing  106 . For example, the sensing apparatuses  108  are mounted to and fixed relative to the sensor body, and thereby fixed relative to the housing  106 . The second sensing apparatus  108   b  can be a same type of sensor as the first sensing apparatus  108   a . The sensing apparatuses  108  may be designed to detect features of the outside world; for example, the sensing apparatuses  108  may be radar sensors, scanning laser range finders, light detection and ranging (LIDAR) devices, or image processing sensors such as cameras. In particular, the sensing apparatuses  108  may be LIDAR devices, e.g., scanning LIDAR devices. A LIDAR device detects distances to objects by emitting laser pulses at a particular wavelength and measuring the time of flight for the pulse to travel to the object and back. The first sensing apparatus  108   a  has a field of view through the first sensor window  110   a  encompassing a region from which the first sensing apparatus  108   a  receives input, and the second sensing apparatus  108   b  has a field of view through a second sensor window  110   b  encompassing a region from which the second sensing apparatus  108   b  receives input. As the sensing apparatuses  108  rotate with the housing  106 , the fields of view encompass a horizontal 360° around the vehicle  100 . 
     The sensor assembly  102  can include at least one sensor window  110 , e.g., two sensor windows  110 . The sensor windows  110  are fixed relative to the housing  106  and rotatable with the housing  106 . The housing  106  includes respective openings  122 , e.g., a first opening  122   a  and a second opening  122   b , in which the sensor windows  110  are positioned. 
     The sensor windows  110  have a collective circumferential extent around the axis A, that is, a collective angular sweep covered by the sensor windows  110 . The circumferential extent around the axis A of each sensor window  110  is an angle θ formed at the axis A between a clockwisemost point and a counterclockwisemost point of that sensor window  110 , i.e., an angular sweep around the axis A from one circumferential end of that sensor window  110  to the other circumferential end of that sensor window  110 . For example, the sensor windows  110  can collectively extend circumferentially around the axis A for at most 90°. The first sensor window  110   a  and the second sensor window  110   b  can each extend circumferentially around the axis A for at most 45°. The comparatively small angular sweep of the sensor windows  110  with respect to the housing  106  provides a small area to keep clean and is accommodated by the fact that the housing  106  and the sensor windows  110  rotate. 
     The sensor windows  110  can be flat. For example, the sensor windows  110  can have a rectangular shape. The sensor windows  110  are transparent with respect to whatever medium the sensing apparatuses  108  are capable of detecting. For example, if the sensing apparatuses  108  are LIDAR devices, then the sensor windows  110  are transparent with respect to visible light at the wavelength generated and detectable by the sensing apparatuses  108 . 
     With reference to  FIG. 3 , the housing  106  includes at least one outer wall  124 , at least one window wall  126 , and at least one nonwindow wall  128 . For example, the housing  106  includes a first outer wall  124   a , a first window wall  126   a , a first nonwindow wall  128   a , a second outer wall  124   b , a second window wall  126   b , and a second nonwindow wall  128   b.    
     The housing  106  can be rotationally symmetric, e.g., second-degree rotationally symmetric. For the purposes of this disclosure, “rotationally symmetric” means looking the same after some rotation by a partial turn around an axis A. A degree of rotational symmetry is a number of distinct orientations in which something looks the same for each rotation. The housing  106  has second-degree rotational symmetry, and the housing  106  looks the same when rotated by 180° so that the second outer wall  124   b , the second window wall  126   b , and the second nonwindow wall  128   b  occupy the space previously occupied by the first outer wall  124   a , the first window wall  126   a , and the first nonwindow wall  128   a , respectively. Specifically, the second outer wall  124   b , the second window wall  126   b , and the second nonwindow wall  128   b  are rotationally symmetric by 180° around the axis A with respect to the first outer wall  124   a , the first window wall  126   a , and the first nonwindow wall  128   a , respectively. The sensor windows  110  are also rotationally symmetric by 180° around the axis A with respect to each other. The following descriptions of the first outer wall  124   a , the first window wall  126   a , the first sensor window  110   a , and the first nonwindow wall  128   a  apply as well to the second outer wall  124   b , the second window wall  126   b , the second sensor window  110   b , and the second nonwindow wall  128   b , respectively. 
     The first outer wall  124   a  has a partial cylindrical shape extending circumferentially at a constant outer radius from the axis A. The first outer wall  124   a  extends circumferentially at the constant outer radius from the second nonwindow wall  128   b  to the first window wall  126   a . The first outer wall  124   a  extends circumferentially for at least 90°. Because of the constant outer radius, the rotational motion of the first outer wall  124   a  does not displace air for the circumferential extent of the first outer wall  124   a , providing smooth airflow onto the first nonwindow wall  128   a . The first outer wall  124   a  extends vertically, i.e., parallel to the axis A, from below the sensor windows  110  to above the sensor windows  110 . 
     The first window wall  126   a  is flat and parallel to the first sensor window  110   a . The first window wall  126   a  extends completely around the first sensor window  110   a , i.e., below, above, and to the sides. The first window wall  126   a  includes the first opening  122   a  in which the first sensor window  110   a  is positioned. The first window wall  126   a  extends from the first outer wall  124   a  to the first nonwindow wall  128   a . The first window wall  126   a  extends in a direction tangent to the first outer wall  124   a . The first window wall  126   a  extends vertically, i.e., parallel to the axis A, from below the first sensor window  110   a  to above the first sensor window  110   a.    
     The first sensor window  110   a  is parallel to the first window wall  126   a . The first sensor window  110   a  is recessed in the first window wall  126   a . The first sensor window  110   a  extends from a point on the housing  106 , e.g., the point on the first opening  122   a  that is closest to the axis A, which is also a point nearest the first outer wall  124   a , in a direction that is radially outward and circumferential relative to the axis A. The first sensor window  110   a  is disposed farther from the axis A than the outer radius of the first outer wall  124   a . An exterior surface of the first sensor window  110   a  faces in a direction that is radially outward and circumferentially in the direction of rotation D relative to the axis A. For the purposes of this disclosure, a direction that a surface “faces” is a direction that is normal, i.e., perpendicular or orthogonal, to that surface. 
     The first nonwindow wall  128   a  extends from the first window wall  126   a  to the second outer wall  124   b . The first nonwindow wall  128   a  can be flat. The first nonwindow wall  128   a  extends in a radially inward direction and possibly a circumferential direction from the first window wall  126   a  relative to the axis A. The first nonwindow wall  128   a  can be nontangent to the second outer wall  124   b . An exterior surface of the first nonwindow wall  128   a  faces in a direction that is radially outward and circumferentially away from the direction of rotation D relative to the axis A. The first nonwindow wall  128   a  extends vertically, i.e., parallel to the axis A, from below the sensor windows  110  to above the sensor windows  110 . 
     The housing  106 , specifically the first outer wall  124   a , the first window wall  126   a , the first nonwindow wall  128   a , the second outer wall  124   b , the second window wall  126   b , and the second nonwindow wall  128   b , can have a constant cross-section from a bottom of the sensor windows  110  to a top of the sensor windows  110 . Except for the openings  122 , the housing  106  can have a constant cross-section from a distance below the sensor windows  110  to a distance above the sensor windows  110 . The constant cross-section can reduce forces tending to roll or pitch the housing  106  as the housing  106  rotates. 
     The disclosure has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. The adjectives “first” and “second” are used throughout this document as identifiers and are not intended to signify importance, order, or quantity. Many modifications and variations of the present disclosure are possible in light of the above teachings, and the disclosure may be practiced otherwise than as specifically described.