Abstract:
A sensor mounting arrangement suitable for an autonomous or automated vehicle having an aerodynamic generally rounded or curved front perimeter surface symmetrically arranged relative to a longitudinal axis of the vehicle. The sensor is mounted so as to be tipped toward a more optimal sensing direction, bringing a leading portion outboard of, and a trailing portion inboard of, the ideal front perimeter surface, but putting the sensor in a more optimal sensing orientation. A transparent cover protects the sensor and blends aerodynamically into the front perimeter body surface.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit under 35 U.S.C. §371 of published PCT Patent Application Number PCT/US2016/14797, filed 26 Jan. 2016 and published as WO2016/126452 on 11 Aug. 2016, which claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 62/112,783, filed Feb. 6, 2015, the entire disclosure of which is hereby incorporated herein by reference. 
     
    
     TECHNICAL FIELD OF INVENTION 
       [0002]    This invention relates to sensor systems on vehicle of the type suitable for autonomously driven vehicles. 
       BACKGROUND OF INVENTION 
       [0003]    Autonomously driven vehicles, and other vehicles using sensors as part of a safety system, utilize radar, LIDAR, sonar, and other sensors mounted around the perimeter of the vehicle to sense the vehicle surroundings. Increasingly, it is desirable that the surroundings be sensed all around the perimeter of the vehicle  10 , a full 360 degrees. Typically, a sensor  12  will have a predetermined spread or “cone” of sensing within which it optimally works, as seen in  FIG. 1 , and labeled O.C. O.C is centered about the lateral or X axis of the vehicle  10 , normal to the length or Y axis. It&#39;s desirable as well to have the flexibility to place such sensors so as to get full perimeter sensing, perhaps with some overlap, but certainly with no significant gap. As seen in  FIG. 1 , this is relatively simple when the sides of the vehicle  10  to which the side sensors  12  are mounted form substantially right angles with the front. 
         [0004]    With a flat fronted vehicle, the sensors  12  on the front side can be easily mounted near the front corner of the vehicle  10 , potentially inside the outer skin of the vehicle  10 , protected and facing in the optimal sensing direction, with the sensing cone OC essentially centered on the X or lateral axis of the vehicle  10 . The central sensors  14  on the can be easily mounted centered near the front of the vehicle  10 , potentially inside the outer skin of the vehicle  10 , protected and facing in the optimal sensing direction, with the sensing cone OC centered on the longitudinal axis Y. 
         [0005]    As seen in  FIG. 2 , the situation is not as optimal with a vehicle  10 ′ in which the perimeter surface  16  of the front end or grill is rounded, both for aesthetic and aerodynamic considerations, wrapping around to the sides of the vehicle  10 ′. This is far more typical for non-commercial passenger vehicles. Then, in order to place the front side mounted sensors  12  in an equivalent position, they must be placed on an exterior bracket  18 , exposed and non-aerodynamic. This places the optimal cone OC of the sensor  12  in substantially the identical position to  FIG. 1 , but with the obvious drawbacks noted. If, instead, as shown in  FIG. 3 , the front side sensors  12  are placed interior to the rounded front perimeter surface  16 , while the sensor  12  is protected and aerodynamic, its sensing cone, indicated at SC to distinguish, diverges substantially from the optimal sensing cone OC by a differential angle alpha. 
       SUMMARY OF THE INVENTION 
       [0006]    The subject invention provides a mounting for the front side sensors which gives environmental and structural protection, with minimal disturbance to the aerodynamic profile of the vehicle, as well as a closer to optimal sensing location. 
         [0007]    In the preferred embodiment disclosed, a front side mounted sensor is fixed to the vehicle body in an orientation that is tipped away from its optimal orientation in terms of sensing, but also tipped away from a position where it can be entirely enclosed inside the perimeter surface of the curved front side of the vehicle. Instead, it is oriented with a leading corner edge outset from, and a trailing corner edge inset from, that perimeter surface. This orients the sensor closer to, but not right at, the optimal orientation that it could have if the perimeter surface of the vehicle were squared off, rather than curved. 
         [0008]    Once fixed, the sensor is covered by a combination of lens and trim piece that together smooth the transition between the perimeter surface and the sensor location, thereby largely preserving the aerodynamics, while covering and protecting the sensor. 
         [0009]    Further features and advantages will appear more clearly on a reading of the following detailed description of the preferred embodiment, which is given by way of non-limiting example only and with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]    The present invention will now be described, by way of example with reference to the accompanying drawings, in which: 
           [0011]      FIG. 1  is a plan view of the front of a prior art sensor placement as described above; 
           [0012]      FIG. 2  is a plan view of another example of a prior art sensor placement; 
           [0013]      FIG. 3  shows an obvious variant of  FIG. 1 ; 
           [0014]      FIG. 4  shows a plan view of a preferred embodiment of the sensor placement of the invention. 
           [0015]      FIG. 5  is a schematic showing the orientation of a sensor. 
           [0016]      FIG. 6  is a view of the lens cover and trim piece used to cover the sensor 
           [0017]      FIG. 7  is a view of just the lens; 
           [0018]      FIG. 8  is a view of a typical LIDAR sensor; and 
           [0019]      FIG. 9  is an enlarged perspective view of the front of the vehicle. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    Referring first to  FIG. 4 , the mounting of front side sensor  12 , described in more detail below, puts the sensing cone SC nearer to the optimal cone location OC, differing therefrom by a smaller differential angle Beta. This is done in such a way as to give sensor  12  complete environmental protection, while substantially preserving the aerodynamic profile. 
         [0021]    Referring next to  FIG. 8 , details of a typical LIDAR sensor  12  are disclosed. While the invention is not limited to such a sensor, it is a typical one in the location indicated for autonomous vehicles. LIDAR is not an acronym, as is commonly believed, but is shorthand for Light Detection and Ranging, an amalgam of Light and Radar. In effect, it is a ranging radar that uses laser light instead of radio waves. LIDAR uses ultraviolet, visible or near infrared light to image objects, and is capable of doing so with a very high level of resolution. Two types of pulse models are available, micropulse, and high energy, with the lower energy, “eye safe” systems being preferable for mobile sensing applications, as here. The particular LIDAR device  12  or  14  used here, though the invention is not limited to such, is an ibeo LUX 2010 Laserscanner, referred to hereafter simply as LIDAR  12  for convenience. It is of the general type described above, with a sensing cone SC as described above of approximately 100 degrees symmetrically arrayed about its center. It is roughly a rectangular prism, with a length L of approximately 150 mm, a width W of approximately 90 millimeters (at the front) and a depth D of approximately 90 mm. The rectangular prism within which the sensor  12  is contained has a leading or front corner edge  20  and a trailing or rear corner edge  22 , both of which are contiguous to the front face  24  of sensor  12 , but are designated front and rear in terms of the location relative to the front and rear of the vehicle  10 ′. As the driver side front sensor  12  is shown, the front and rear edge designation would be reversed if the sensor were to be mounted on the passenger side. The essential point is that the front face  24  of the sensor  12  is bounded by two edges  22  and  24 , which are oriented as described next to achieve the desired result. 
         [0022]    Referring next to  FIG. 5 , sensor  12  is mounted to the vehicle, and relative to the line  16  that defines the front surface  16  of vehicle  10 ′, in an orientation that tips the leading corner edge  20  outside of, and the trailing corner concurrently inside of, the front surface  16 , so as to bring the front face  26  of the sensor closer toward a position parallel to the length axis of the vehicle, that is, closer than it would be if both corner edges  22  and  24  were inboard of the front surface  16 . Again, by comparison, both corners are in that inboard location as shown in  FIG. 3 . Considering the line that defines the front surface  16  to be essentially straight at the point where the plane of sensor front surface  26  crosses it in  FIG. 5 , the angle of tip T is approximately 45 degrees, though it could be more or less, likely anywhere in a range of 70 to 10 degrees, or any subrange thereof. The point is, that by tipping the leading or front corner edge outboard of, and the rear of trailing corner edge inboard of the front perimeter surface of the vehicle, the sensor is placed in the orientation of  FIG. 4 , which is closer to the ideal orientation of  FIG. 2  than it would be if it were mounted entirely inboard of perimeter surface  16 , as shown in  FIG. 3 . 
         [0023]    Referring next to  FIGS. 5, 6 and 7 , the protection of sensor  12  from the ambient is provided by a translucent or transparent polycarbonate or acrylic glass cover, indicated generally at  28 , which is generally L shaped, with a shorter leading leg  30  and longer trailing leg  32 . Being transparent or translucent, cover  28  can be tinted to match or blend with a desired vehicle body color, such as light gray, so long as it is operationally transparent to infrared light. In the case of some other sensor, the cover would be of a material “transparent” to whatever signal it emitted and or received, such as radio waves. Cover  28  is mounted within a perimeter trim piece  34  that is fitted to the front of vehicle  10 ′ so as to orient the cover  28  over sensor  12 , with the longer, trailing leg  32  generally parallel to sensor front surface  26 , and with shorter, leading leg  30  located over the sensor front or leading corner edge  20 . 
         [0024]    Referring next to  FIG. 9 , it can be seen that the surfaces of both legs  30  and  32  intersect and generally blend into the vehicle front surface  16 , thereby creating an aerodynamic profile that does not depart very far from the original surface  16 . The seal between the cover  28  and trim piece  34 , and in turn between the supporting the trim piece  34  and the vehicle body, is weather tight and protective. The cover  28  presents a relatively smooth and aerodynamic profile. Specifically, the short, leading leg  30  presents a convex, wind cutting profile while the longer leg  32  presents a longer and less abrupt trailing profile that steadies the air currents and does not become concave relative to the front surface  16  until relatively close to its own trailing edge. That trailing edge concavity can, depending of the angle of tip, be minimized. 
         [0025]    While this invention has been described in terms of the preferred embodiments thereof, it is not intended to be so limited, but rather only to the extent set forth in the claims that follow.