Patent Description:
Autonomous vehicles, such as vehicles that do not require a human driver, can be used to aid in the transport of trailered (e.g., towed) cargo, such as freight, livestock or other items from one location to another. Other types of articulated vehicles may also transport cargo or passengers. Such vehicles may operate in a fully autonomous mode without any in-vehicle passenger input or a partially autonomous mode where a person may provide some driving input. One or more sensors can be used to detect nearby objects in the environment, and the vehicle may use information from the sensors when driving in an autonomous mode. Depending on the size, shape and orientation of the vehicle, there may be one or more blind spots around the vehicle. Blind spots may be reduced by adding more sensors. However, each added sensor results in increased cost and may increase computer processing power requirements. Also, this approach may not be physically feasible in certain instances.

<CIT> describes methods and apparatuses that enable a radar system to transmit radar signals into lanes on a roadway in which a vehicle may turn. For example, when a car is making a protected right turn, that is a right turn when there is another vehicle traveling in the same direction in a lane adjacent to the lane of the turning vehicle, a traditional radar may have its view of the lane in which it is turning obscured by the vehicle in the lane adjacent to the lane of the turning vehicle. By using radar deflectors strategically located near the front of the vehicle, the radar signals may be deflected at angles to avoid being obstructed by the vehicle in the lane adjacent to the lane of the turning vehicle.

<CIT> describes a system and method for collecting and processing sensor data for facilitating and/or enabling autonomous, semi-autonomous, and remote operation of a vehicle, including: collecting surroundings at one or more sensors, and determining properties of the surroundings of the vehicle and/or the behavior of the vehicle based on the surroundings data at a computing system.

<CIT> describes an autonomous mobile device (<NUM>) which moves while detecting (i) an obstacle present ahead of the autonomous mobile device (<NUM>) and (ii) a difference in level of a floor surface, including: a laser range finder (<NUM>) which measures a distance to an object present in a scan area by scanning the scan area while emitting a laser beam in parallel to the floor surface; and mirrors (22a, 22b) each of which is provided within the scan area scanned by the laser range finder (<NUM>) and each of which reflects part of the laser beam to the floor surface.

<CIT> describes a control system for a vehicle includes a camera module having a plurality of cameras. A control is operable to adjust a field of view of the cameras responsive to an input. When the vehicle is traveling in and along a traffic lane, the control sets the field of view of at least some of the cameras forward through the vehicle windshield. Responsive to an input indicative of an intended lane change, the control adjusts at least one camera to set the field of view of the camera toward an exterior rearview mirror at the side of the vehicle at which the target lane is located. Responsive to determination, via processing of captured image data when the camera views the exterior rearview mirror of the vehicle, that the target lane is clear, the control controls the at least one vehicle control system to maneuver the vehicle into the target lane.

All vehicles have blind spots that may impair the field of view (FOV) of the driver or on-board computer system in the case of a vehicle capable of operating in a self-driving mode. Large-sized vehicles such as cargo vehicles, buses and construction equipment can encounter particular challenges compared to smaller passenger vehicles such as sedans or vans. For instance, the trailer of a cargo truck may obstruct the FOV of sensors mounted on the truck's tractor, especially during a turning maneuver. And due to the size of the truck, the blind spot(s) may be significantly larger than those of a smaller passenger vehicle.

Careful sensor placement can help to reduce blind spots. Employing additional sensors on the vehicle can further minimize blind spots. However, adding sensors can increase system cost as well as processing complexity, for example from a sensor fusion perspective. Regardless of the number or type of added sensors, some areas around the vehicle may be obscured or have reduced visibility due to physical limitations on where the sensors can be placed.

The technology described herein employs one or more reflective components (mirrors) located external to the sensor to increase the sensor's effective FOV. Such mirrors can reflect or redirect beams that would otherwise be wasted. By way of example, the main lidar sensor on the roof of the tractor of a cargo vehicle may rotate to provide a <NUM>° FOV. As it rotates through various yaw positions, multiple beams are emitted across a set of pitches (e.g., between +<NUM>° to -<NUM>°). Some beams may be wasted due to obstruction by the trailer. Other beams may be wasted because they are emitted at high pitch angles to the side. Using mirrors to redirect these and other beams emitted from the lidar sensor can help address the blind spot issue and provide enhanced visibility around external obstructions, e.g., a large truck between the vehicle and another object. Depending on the configuration and materials, the mirrors may also be employed with other types of sensors (e.g., cameras and radar).

According to one aspect of the technology, a vehicle is configured to operate in an autonomous driving mode. The vehicle comprises a driving system, a perception system, one or more mirrors and a control system. The driving system includes a steering subsystem, an acceleration subsystem and a deceleration subsystem to control driving of the vehicle in the autonomous driving mode. The perception system includes one or more sensors configured to detect objects in an environment surrounding the vehicle based on obtained sensor data. Each of the sensors is disposed in a respective housing positioned along the vehicle. The one or more mirrors are remote from the respective housings of the one or more sensors. The one or more mirrors are configured to reflect received signals towards at least one of the one or more sensors to enhance a sensor field of view. The control system is operatively connected to at least the driving system and the perception system. The control system has one or more computer processors configured to receive sensor data corresponding to the enhanced sensor field of view from the perception system and to direct the driving system when operating in the autonomous driving mode based on the sensor data received from the perception system.

In one example, the vehicle further comprises a calibration system configured to detect an amount of vibration for the one or more mirrors and to provide information regarding the detected amount of vibration to the perception system or the control system during processing of the obtained sensor data. The calibration system may be part of the perception system or the control system.

In another example, the one or more mirrors are further configured to reflect emitted signals from the one or more sensors to the environment. Here, the emitted signals may include laser light or radio waves, and the received signals may be at least one of laser light, radio waves, optical imagery or infrared imagery.

In another example, the one or more mirrors are planar front surface mirrors. In a further example, the one or more mirrors are rigidly affixed to a surface of the vehicle. In yet another example, a given one of the one or more mirrors extends externally from the respective housing of a corresponding one of the one or more sensors.

In a further example, the one or more mirrors are configured to deploy away from a surface of the vehicle during operation of the vehicle in the autonomous driving mode. Deployment may include the one or more mirrors popping out from a surface of the vehicle. The vehicle may include a servo mechanism configured to control deployment of the one or more mirrors. Here, the servo mechanism may be further configured to steer the one or more mirrors. Alternatively, the servo mechanism is further configured to dampen vibration of the one or more mirrors.

In another example, the one or more mirrors includes a first mirror and a second mirror. According to one scenario, the first and second mirrors may be non-coplanar.

The vehicle may be a truck having a tractor unit, with the tractor unit including a coupling system to pivotally coupled to a trailer. In this case, the one or more mirrors may be disposed along respective surfaces of the tractor unit. Alternatively and/or additionally, the vehicle includes the trailer and at least one of the one or more mirrors is disposed along the trailer.

According to another aspect, a method of operating a vehicle in an autonomous driving mode comprises receiving, by one or more processors of a control system of the vehicle, obtained sensor data from one or more sensors configured to detect objects in an environment surrounding the vehicle, each of the one or more sensors being disposed in a respective housing positioned along the vehicle and having a respective field of view; receiving, by the one or more processors, reflected signals from one or more mirrors remote from the respective housings of the one or more sensors, the one or more mirrors being configured to reflect received signals towards at least one of the one or more sensors to provide an enhanced a sensor field of view; and controlling, by the one or more processors, a driving system of the vehicle when operating in the autonomous driving mode, in response to the received obtained sensor data and the received reflected signals that provide the enhanced sensor field of view. The method further comprises controlling operation of at least one of the one or more mirrors by dampening vibration of the at least one mirror.

The method may further comprise controlling operation of at least one of the one or more mirrors by: deploying the at least one mirror away from a surface of the vehicle during operation of the vehicle in the autonomous driving mode; steering the at least one mirror; and/or retracting the at least one mirror onto or into the vehicle when not in use. The method may alternatively or additionally further include calibrating the one or more mirrors prior to or during operation in the autonomous driving mode.

The technology relates to fully autonomous or semi-autonomous vehicles, including cargo vehicles (e.g., tractor-trailers) and other articulated vehicles (e.g., buses), construction or farm vehicles, as well as passenger vehicles (e.g., sedans and minivans). On-board sensors, such as lidar sensors, are used to detect objects in the vehicle's environment. These sensors may also detect the real-time pose of the vehicle. Reflective components (mirrors) are employed to reduce sensor blind spots and enhance sensor FOV. These and other aspects are discussed in detail below.

<FIG> illustrate an example vehicle <NUM>, such as a tractor-trailer truck. The truck may include, e.g., a single, double or triple trailer, or may be another medium or heavy duty truck such as in commercial weight classes <NUM> through <NUM>. As shown, the truck includes a tractor unit <NUM> and a single cargo unit or trailer <NUM>. The trailer <NUM> may be fully enclosed, open such as a flat bed, or partially open depending on the type of cargo to be transported. The tractor unit <NUM> includes the engine and steering systems (not shown) and a cab <NUM> for a driver and any passengers. In a fully autonomous arrangement, the cab <NUM> may not be equipped with seats or manual driving components, since no person may be necessary.

The trailer <NUM> includes a hitching point, known as a kingpin, <NUM>. The kingpin <NUM> is typically formed as a solid steel shaft, which is configured to pivotally attach to the tractor unit <NUM>. In particular, the kingpin <NUM> attaches to a trailer coupling <NUM>, known as a fifth-wheel, that is mounted rearward of the cab. For a double or triple tractor-trailer, the second and/or third trailers may have simple hitch connections to the leading trailer. Or, alternatively, according to one aspect of the disclosure, each trailer may have its own kingpin. In this case, at least the first and second trailers could include a fifth-wheel type structure arranged to couple to the next trailer.

As shown, the tractor may have one or more sensor units <NUM>, <NUM> disposed therealong. For instance, one or more sensor units <NUM> may be disposed on a roof or top portion of the cab <NUM>, and one or more side sensor units <NUM> may be disposed on left and/or right sides of the cab <NUM>. Sensor units may also be located along other regions of the cab <NUM>, such as along the front bumper or hood area, in the rear of the cab, adjacent to the fifth-wheel, underneath the chassis, etc. The trailer <NUM> may also have one or more sensor units <NUM> disposed therealong, for instance along a side panel, front, rear, roof and/or undercarriage of the trailer <NUM>. <FIG> illustrate an example of another type of articulated vehicle <NUM>, such as an articulated bus. As with the tractor-trailer <NUM>, the articulated bus <NUM> may include one or more sensor units disposed along different areas of the vehicle.

<FIG> is a perspective view of an exemplary passenger vehicle <NUM>. Similar to vehicles <NUM> and <NUM>, the vehicle <NUM> includes various sensors for obtaining information about the vehicle's external environment. For instance, a roof-top housing <NUM> and dome arrangement <NUM> may include a lidar sensor as well as various cameras and/or radar units. Housing <NUM>, located at the front end of vehicle <NUM>, and housings 148a, 148b on the driver's and passenger's sides of the vehicle may each store a lidar or other sensor. For example, each housing <NUM> may be located in front of the driver's side door. Vehicle <NUM> also includes housings 150a, 150b for radar units, lidar and/or cameras also located towards the rear roof portion of the vehicle. Additional lidar, radar units and/or cameras (not shown) may be located at other places along the vehicle <NUM>. For instance, arrow <NUM> indicates that a sensor unit may be positioned along the read of the vehicle <NUM>, such as on or adjacent to the bumper. And arrow <NUM> indicates that another sensor unit may be positioned on the undercarriage of the vehicle.

By way of example, as discussed further below each sensor unit may include one or more sensors within one housing, such as lidar, radar, camera (e.g., optical or infrared), acoustical (e.g., microphone or sonar-type sensor), inertial (e.g., accelerometer, gyroscope, etc.) or other sensors.

<FIG> illustrates a block diagram <NUM> with various components and systems of a vehicle, such as a truck, farm equipment or construction equipment, configured to operate in a fully or semi-autonomous mode of operation. By way of example, there are different degrees of autonomy that may occur for a vehicle operating in a partially or fully autonomous driving mode. National Highway Traffic Safety Administration and the Society of Automotive Engineers have identified different levels to indicate how much, or how little, the vehicle controls the driving. For instance, Level <NUM> has no automation and the driver makes all driving-related decisions. The lowest semi-autonomous mode, Level <NUM>, includes some drive assistance such as cruise control. Level <NUM> has partial automation of certain driving operations, while Level <NUM> involves conditional automation that can enable a person in the driver's seat to take control as warranted. In contrast, Level <NUM> is a high automation level where the vehicle is able to drive without assistance in select conditions. And Level <NUM> is a fully autonomous mode in which the vehicle is able to drive without assistance in all situations. The architectures, components, systems and methods described herein can function in any of the semi or fully-autonomous modes, e.g., Levels <NUM>-<NUM>, which are referred to herein as "autonomous" driving modes. Thus, reference to an autonomous driving mode includes both partial and full autonomy.

As shown in the block diagram of <FIG>, the vehicle includes a control system of one or more computing devices, such as computing devices <NUM> containing one or more processors <NUM>, memory <NUM> and other components typically present in general purpose computing devices. The control system may constitute an electronic control unit (ECU) of a tractor unit. The memory <NUM> may be of any type capable of storing information accessible by the processor, including a computing device-readable medium. The memory is a non-transitory medium such as a hard drive, memory card, optical disk, solid state device, tape memory, or the like. Systems may include different combinations of the foregoing, whereby different portions of the instructions and data are stored on different types of media.

The data <NUM> may be retrieved, stored or modified by one or more processors <NUM> in accordance with the instructions <NUM>. As an example, data <NUM> of memory <NUM> may store information, such as calibration information, to be used when calibrating different types of sensors, mirrors and other parts of a perception system.

The one or more processor <NUM> may be any conventional processors, such as commercially available CPUs. Alternatively, the one or more processors may be a dedicated device such as an ASIC or other hardware-based processor, FPGA or the like. Although <FIG> functionally illustrates the processor(s), memory, and other elements of computing devices <NUM> as being within the same block, such devices may actually include multiple processors, computing devices, or memories that may or may not be stored within the same physical housing. Similarly, the memory <NUM> may be a hard drive or other storage media located in a housing different from that of the processor(s) <NUM>. Accordingly, references to a processor or computing device will be understood to include references to a collection of processors or computing devices or memories that may or may not operate in parallel.

In one example, the computing devices <NUM> may form an autonomous driving computing system incorporated into vehicle <NUM>. The autonomous driving computing system may be capable of communicating with various components of the vehicle in order to perform route planning and driving operations. For example, the computing devices <NUM> may be in communication with various systems of the vehicle, such as a driving system including a deceleration system <NUM> (for controlling braking of the vehicle), acceleration system <NUM> (for controlling acceleration of the vehicle), steering system <NUM> (for controlling the orientation of the wheels and direction of the vehicle), signaling system <NUM> (for controlling turn signals), navigation system <NUM> (for navigating the vehicle to a location or around objects) and a positioning system <NUM> (for determining the position of the vehicle).

The computing devices <NUM> are also operatively coupled to a perception system <NUM> (for detecting objects in the vehicle's environment), a power system <NUM> (for example, a battery and/or gas or diesel powered engine) and a transmission system <NUM> in order to control the movement, speed, etc., of the vehicle in accordance with the instructions <NUM> of memory <NUM> in an autonomous driving mode which does not require or need continuous or periodic input from a passenger of the vehicle. Some or all of the wheels/tires <NUM> are coupled to the transmission system <NUM>, and the computing devices <NUM> may be able to receive information about tire pressure, balance and other factors that may impact driving in an autonomous mode.

The computing devices <NUM> may control the direction and speed of the vehicle by controlling various components. By way of example, computing devices <NUM> may navigate the vehicle to a destination location completely autonomously using data from the map information and navigation system <NUM>. Computing devices <NUM> may use the positioning system <NUM> to determine the vehicle's location and the perception system <NUM> to detect and respond to objects when needed to reach the location safely. In order to do so, computing devices <NUM> may cause the vehicle to accelerate (e.g., by increasing fuel or other energy provided to the engine by acceleration system <NUM>), decelerate (e.g., by decreasing the fuel supplied to the engine, changing gears (e.g., via the transmission system <NUM>), and/or by applying brakes by deceleration system <NUM>), change direction (e.g., by turning the front or other wheels of vehicle <NUM> by steering system <NUM>), and signal such changes (e.g., by lighting turn signals of signaling system <NUM>). Thus, the acceleration system <NUM> and deceleration system <NUM> may be a part of a drivetrain or other transmission system <NUM> that includes various components between an engine of the vehicle and the wheels of the vehicle. Again, by controlling these systems, computing devices <NUM> may also control the transmission system <NUM> of the vehicle in order to maneuver the vehicle autonomously.

As an example, computing devices <NUM> may interact with deceleration system <NUM> and acceleration system <NUM> in order to control the speed of the vehicle. Similarly, steering system <NUM> may be used by computing devices <NUM> in order to control the direction of vehicle. For example, if the vehicle is configured for use on a road, such as a tractor-trailer truck or a construction vehicle, the steering system <NUM> may include components to control the angle of the wheels of the tractor unit to turn the vehicle. Signaling system <NUM> may be used by computing devices <NUM> in order to signal the vehicle's intent to other drivers or vehicles, for example, by lighting turn signals or brake lights when needed.

Navigation system <NUM> may be used by computing devices <NUM> in order to determine and follow a route to a location. In this regard, the navigation system <NUM> and/or data <NUM> may store map information, e.g., highly detailed maps that computing devices <NUM> can use to navigate or control the vehicle. As an example, these maps may identify the shape and elevation of roadways, lane markers, intersections, crosswalks, speed limits, traffic signal lights, buildings, signs, real time traffic information, vegetation, or other such objects and information. The lane markers may include features such as solid or broken double or single lane lines, solid or broken lane lines, reflectors, etc. A given lane may be associated with left and right lane lines or other lane markers that define the boundary of the lane. Thus, most lanes may be bounded by a left edge of one lane line and a right edge of another lane line.

The perception system <NUM> also includes one or more sensors or other components for detecting objects external to the vehicle such as other vehicles, obstacles in the roadway, traffic signals, signs, trees, etc. For example, the perception system <NUM> may include one or more light detection and ranging (lidar) sensors, acoustical (e.g., microphone or sonar) devices, radar units, cameras (e.g., optical and/or infrared), inertial sensors (e.g., gyroscopes or accelerometers), pressure sensors, and/or any other detection devices that record data which may be processed by computing devices <NUM>. The sensors of the perception system <NUM> may detect objects and their characteristics such as location, orientation, size, shape, type (for instance, vehicle, pedestrian, bicyclist, vegetation, etc.), heading, and speed of movement, etc. The raw data from the sensors (e.g., lidar point clouds) and/or the aforementioned characteristics can sent for further processing to the computing devices <NUM> periodically or continuously as it is generated by the perception system <NUM>. Computing devices <NUM> may use information from the positioning system <NUM> to determine the vehicle's location and the perception system <NUM> to detect and respond to objects when needed to reach the location safely, including planning changes to the route and/or modifying driving operations.

As indicated in <FIG>, the perception system <NUM> includes one or more sensor assemblies <NUM>. Each sensor assembly <NUM> may include one or more sensors at least partly received in a housing. In one example, the sensor assemblies <NUM> may be arranged as sensor towers integrated into the side-view mirrors on the truck, farm equipment, construction equipment, bus or the like. Sensor assemblies <NUM> may also be positioned at different locations on the tractor unit <NUM> or on the trailer <NUM>, as noted above with regard to <FIG>. The computing devices <NUM> may communicate with the sensor assemblies located on both the tractor unit <NUM> and the trailer <NUM>. Each assembly may have one or more types of sensors such as those described above.

The vehicle <NUM> also includes one or more mirrors <NUM>, which may be part of the perception system <NUM> as shown, or which may be separate from the perception system. The mirror(s) <NUM> is used to reflect a beam and direct it to or from one or more sensors of the perception system <NUM>. As discussed further below, each mirror may be placed at a particular location along the vehicle external to a corresponding sensor assembly. In some instances, the mirror may be rigidly affixed to the vehicle. In other instances, the mirror may be pivotally or otherwise adjustably affixed to the vehicle. Here, the mirror may be raised from a surface or receptacle of the vehicle when in use, and lowered towards the surface or receptacle when not in use. And in still other instances, the mirror may be coupled to and extend from a sensor assembly.

The autonomous driving computing system may perform calibration of individual sensors and their associated mirrors, all sensors in a particular sensor assembly relative to a commonly used mirror, between sensors in different sensor assemblies, between multiple mirrors in case of non-coplanar setups, etc. This may be done using a calibration system <NUM>, which may be part of the perception system <NUM>, the computing devices <NUM> or some other part of the autonomous driving computing system. In one example, the calibration system <NUM>, perception system <NUM>, computing devices <NUM> and other systems may be directly or indirectly connected via a Controller Area Network (CAN bus) of the vehicle.

Also shown in <FIG> is a coupling system <NUM> for connectivity between the tractor unit and the trailer. The coupling system <NUM> includes one or more power and/or pneumatic connections <NUM>, and a fifth-wheel <NUM> at the tractor unit for connection to the kingpin at the trailer.

<FIG> illustrates an example block diagram <NUM> of a trailer. As shown, the system includes an ECU <NUM> of one or more computing devices, such as computing devices containing one or more processors <NUM>, memory <NUM> and other components typically present in general purpose computing devices. The memory <NUM> stores information accessible by the one or more processors <NUM>, including instructions <NUM> and data <NUM> that may be executed or otherwise used by the processor(s) <NUM>. The descriptions of the processors, memory, instructions and data from <FIG> apply to these elements of <FIG>.

The ECU <NUM> is configured to receive information and control signals from the trailer unit. The on-board processors <NUM> of the ECU <NUM> may communicate with various systems of the trailer, including a deceleration system <NUM> (for controlling braking of the trailer), signaling system <NUM> (for controlling turn signals), and a positioning system <NUM> (to assist in determining the location of the trailer). The ECU <NUM> may also be operatively coupled to a perception system <NUM> with one or more sensors for detecting objects in the trailer's environment. One or more mirrors may be included as part of the perception system <NUM> or separate from the perception system. A power system <NUM> (for example, a battery power supply) provides power to local components on the trailer. Some or all of the wheels/tires <NUM> of the trailer may be coupled to the deceleration system <NUM>, and the processors <NUM> may be able to receive information about tire pressure, balance, wheel speed and other factors that may impact driving in an autonomous mode, and to relay that information to the processing system of the tractor unit. The deceleration system <NUM>, signaling system <NUM>, positioning system <NUM>, perception system <NUM>, power system <NUM> and wheels/tires <NUM> may operate in a manner such as described above with regard to <FIG>.

The trailer also includes a set of landing gear <NUM>, as well as a coupling system <NUM>. The landing gear provide a support structure for the trailer when decoupled from the tractor unit. The coupling system <NUM>, which may be a part of coupling system <NUM>, provides connectivity between the trailer and the tractor unit. The coupling system <NUM> may include a connection section <NUM> (e.g., for power and/or pneumatic links) to provide backward compatibility with legacy trailer units that may or may not be capable of operating in an autonomous mode. The coupling system also includes a kingpin <NUM> configured for connectivity with the fifth-wheel of the tractor unit.

While the components and systems of <FIG> are described in relation to a tractor-trailer arrangement, as noted above the technology may be employed with other types of articulated vehicles, such as the articulate bus <NUM> of <FIG>.

<FIG> illustrates a block diagram <NUM> with various components and systems of a passenger-type vehicle such as shown in <FIG>, configured to operate in a fully or semi-autonomous mode of operation. The passenger-type vehicle may be, e.g., a car, motorcycle, recreational vehicles, etc. The block diagram <NUM> shows that the passenger vehicle may have components and systems that are equivalent to what is shown and described in block diagram <NUM>, for instance to form an autonomous driving computing system for controlling vehicle <NUM> of <FIG>.

A user interface system <NUM> may include, e.g., a mouse, keyboard, touch screen and/or microphone, as well as one or more displays (e.g., a touch screen display with or without haptic feedback, a heads-up display, or the like) that is operable to display information to passengers in the vehicle. In this regard, an internal electronic display may be located within a cabin of vehicle <NUM> (not shown) and may be used by computing devices <NUM> to provide information to the passengers.

Also shown in <FIG> is a communication system <NUM>. The communication system <NUM> may also include one or more wireless connections to facilitate communication with other computing devices, such as passenger computing devices within the vehicle, and computing devices external to the vehicle, such as in another nearby vehicle on the roadway or a remote server system. The wireless connections may include short range communication protocols such as Bluetooth™ or Bluetooth™ low energy (LE), cellular connections, etc. Various configurations and protocols may be employed, such as Ethernet, WiFi and HTTPS, for communication via the Internet, intranets, virtual private networks, wide area networks, local networks, private networks using communication protocols proprietary to one or more companies, and various combinations of the foregoing.

In view of the structures and configurations described above and illustrated in the figures, various implementations will now be described.

Information obtained from one or more sensors is employed so that the vehicle may operate in an autonomous mode. Each sensor, or type of sensor, may have a different range, resolution and/or field of view (FOV).

For instance, the sensors may include a long range, narrow FOV lidar and a short range, tall FOV lidar. In one example, the long range lidar may have a range exceeding <NUM>-<NUM> meters, while the short range lidar has a range no greater than <NUM>-<NUM> meters. Alternatively, the short range lidar may generally cover up to <NUM>-<NUM> meters from the vehicle while the long range lidar may cover a range exceeding <NUM> meters. In another example, the long range is between <NUM>-<NUM> meters, while the short range has a range of <NUM>-<NUM> meters. In a further example, the long range exceeds <NUM> meters while the short range is below <NUM> meters. Intermediate ranges of between, e.g., <NUM>-<NUM> meters can be covered by one or both of the long range and short range lidars, or by a medium range lidar that may also be included in the sensor system. The medium range lidar may be disposed between the long and short range lidars in a single housing. In addition to or in place of these lidars, a set of cameras may be arranged, for instance to provide forward, side and rear-facing imagery. Similarly, a set of radar sensors may also be arranged to provide forward, side and rear-facing data. Other sensors may include an inertial sensor such as a gyroscope, an accelerometer, etc..

Examples of lidar, camera and radar sensors and their fields of view are shown in <FIG> and <FIG>. In example <NUM> of <FIG>, one or more lidar units may be located in rooftop sensor housing <NUM>, with other lidar units in side sensor housings <NUM>. In particular, the rooftop sensor housing <NUM> may be configured to provide a <NUM>° FOV. A pair of sensor housings <NUM> may be located on either side of the tractor unit cab, for instance integrated into a side view mirror assembly, along a side door or quarterpanel of the cab, or extending out laterally along one or both sides of the cab roof. In one scenario, long range lidars may be located along a top or upper area of the sensor housings <NUM> and <NUM>. The long range lidar may be configured to see over the hood of the vehicle. And short range lidars may be located in other portions of the sensor housings <NUM> and <NUM>. The short range lidars may be used by the perception system to determine whether an object such as another vehicle, pedestrian, bicyclist, etc. is next to the front or side of the vehicle and take that information into account when determining how to drive or turn. Both types of lidars may be co-located in the housing, for instance aligned along a common vertical axis.

As illustrated in <FIG>, the lidar(s) in the rooftop sensor housing <NUM> may have a FOV <NUM>. Here, as shown by region <NUM>, the trailer or other articulating portion of the vehicle may provide signal returns, and may partially or fully block a rearward view. Long range lidars on the left and right sides of the tractor unit have fields of view <NUM>. These can encompass significant areas along the sides and front of the vehicle. As shown, there may be an overlap region <NUM> of their fields of view in front of the vehicle. The overlap region <NUM> provides the perception system with additional or information about a very important region that is directly in front of the tractor unit. This redundancy also has a safety aspect. Should one of the long range lidar sensors suffer degradation in performance, the redundancy would still allow for operation in an autonomous mode. Short range lidars on the left and right sides may have different (e.g., smaller) fields of view <NUM>. A space is shown between different fields of view for clarity in the drawing; however in actuality there may be no break in the coverage. The specific placements of the sensor assemblies and fields of view is merely exemplary, and may different depending on, e.g., the type of vehicle, the size of the vehicle, FOV requirements, etc..

<FIG> illustrates an example configuration <NUM> for either (or both) of radar and camera sensors in a rooftop housing and on both sides of a tractor-trailer vehicle. Here, there may be multiple radar and/or camera sensors in each of the sensor housings <NUM> and <NUM>. As shown, there may be sensors in the rooftop housing with front fields of view <NUM>, side fields of view <NUM> and rear fields of view <NUM>. As with region <NUM>, the trailer may impact the ability of the sensor to detect objects behind the vehicle. Sensors in the sensor housings <NUM> may have forward facing fields of view <NUM> (and side and/or rear fields of view as well). As with the lidars discussed above with respect to <FIG>, the sensors of <FIG> may be arranged so that the adjoining fields of view overlap, such as shown by overlapping region <NUM>. The overlap regions here similarly can provide redundancy and have the same benefits should one sensor suffer degradation in performance.

<FIG> illustrates a vehicle using sensor assembly to scan for objects in the environment. The sensor assembly may be, e.g., rooftop sensor housing <NUM> of <FIG>. The sensor assembly may include one or more lidar, radar, camera or other sensors therein. Solid and dashed lines emanating from the housing indicate examples of individual scans of the environment. For instance, <NUM> (or more or less) individual scans may be made by a given sensor per scan period. This may include adjusting the sensor's FOV up or down, left or right, e.g., with a motor, servo or other actuator. The individual scans may be selected to cover particular portions of the sensor's FOV or selected regions around the vehicle.

<FIG> illustrates a top-down view <NUM> of an obstructed FOV, for instance due to a trailer of the vehicle. Here, the sensor (e.g., a lidar sensor) may be located on a roof of the vehicle. Only a portion of the trailer is shown, as indicated by the dash-dot line towards the rear of the trailer. The sensor's overall FOV <NUM> may be obstructed by corners of the trailer, as shown by FOV edges <NUM>. In order to overcome such an obstruction, according to one aspect reflective surfaces (mirrors) may be used to redirect emitted light beams or radio waves from a sensor towards the obstructed area. According to another aspect, received light beams, radio waves or imagery are reflected off of the mirror(s) towards the sensor. The sensor may have a transmitter portion (e.g., laser, transmit antenna) for emitted light beams or radio waves and/or a receiver portion (e.g., photodetector, receive antenna, CCD or CMOS image sensor) for received light beams, radio waves or imagery.

In one example, existing mirrors (e.g., side view mirrors) or other reflective surfaces can be employed. In other examples, one or more mirrors may be distributed at different places along the tractor, trailer or other parts of the vehicle. This could include placing one or more mirrors along the cab, a fairing on the tractor or trailer, extending from a portion of the sensor housing, etc. Various examples are shown in <FIG>.

For instance, <FIG> illustrate a scenario <NUM> using side-view mirrors <NUM> located on either side of the vehicle cab. In this example, the sensor may be a lidar sensor that emits laser light as shown by dashed line <NUM>. One or more beams of the emitted light are directed toward and reflect off of the mirror <NUM>. The reflected beams, shown by dashed line <NUM>, may be directed toward a blind spot or other area around the vehicle. Light received from the environment, as shown by dotted line <NUM>, is reflected off of a mirror <NUM> and directed toward the sensor, as shown by dotted line <NUM>. For ease of illustration in this figure, emitted light is shown reflecting off of the mirror on the left side of the vehicle while received light is shown reflecting off of the mirror on the right side of the vehicle. In operation, each mirror may be used to emit and/or receive laser light (or RF waves, optical or infrared imagery, etc.). <FIG> illustrates a perspective view <NUM> of the scenario, showing a mirror reflecting the beam (or radio waves) towards and from a blind spot along the rear of the vehicle. Shorter dashed lines <NUM> illustrate emitted beams (or radio waves) that are not reflected by the mirror but which may be blocked by a portion of the vehicle (e.g., a front or side surface of the trailer).

<FIG> illustrate a scenario <NUM> using mirrors <NUM> located on or extending from one or more surfaces of the vehicle, such as the cab. As above, the sensor may be a lidar sensor that emits laser light as shown by dashed line <NUM>. One or more beams of the emitted light are directed toward and reflect off of the mirror <NUM>. The reflected beams, shown by dashed line <NUM>, may be directed toward a blind spot or other area around the vehicle. Light received from the environment, as shown by dotted line <NUM>, is reflected off of a mirror <NUM> and directed toward the sensor, as shown by dotted line <NUM>. Again, for ease of illustration, emitted light is shown reflecting off of the mirror on the left side of the vehicle while received light is shown reflecting off of the mirror on the right side of the vehicle. In operation, each mirror may be used to emit and/or receive laser light (or RF waves, optical or infrared imagery, etc.). <FIG> illustrates a perspective view <NUM> of the scenario, showing a mirror reflecting the beam (or radio waves) towards and from a blind spot along the rear of the vehicle. Shorter dashed lines <NUM> illustrate emitted beams (or radio waves) that are not reflected by the mirror but which may be blocked by a portion of the vehicle (e.g., a surface of the trailer). In this scenario, the mirror(s) <NUM> may be rigidly affixed or otherwise permanently positioned to a surface of the vehicle.

Alternatively, the mirror(s) <NUM> may be configured to pop up or otherwise extend from the vehicle during use, and retract onto or into the vehicle when not in use. In one scenario, pop-up mirrors could be used on an as-needed basis, for instance when the perception system determines that a blind spot exists or that a determined blind spot exceeds some threshold size. This would reduce wind drag during typical vehicle operation. In this case, a mirror could be extended one or more preset or calculated distances in specific situations. Such pop-up mirrors could also be steerable, for instance via a servo mechanism that provides one or more degrees of freedom, e.g., by panning and/or tilting the mirror or an arm member that couples the mirror to the vehicle. Here, the servo mechanism could be used to reflect beams toward (or from) needed areas of visibility. For example, when the vehicle is driving in a crowded surroundings, the system can pop up mirrors to reflect high light beams down to the nearby areas. The servo mechanism could also be used in conjunction with a calibration system to address vibration-related issues, for instance by dampening vibration of a mirror.

<FIG> illustrate another scenario <NUM> using one or more first mirrors <NUM> located on or extending from one or more surfaces of the vehicle (e.g., the cab), and one or more second mirrors <NUM> along another part of the vehicle (e.g., a corner or fairing of the trailer). As above, the sensor may be a lidar sensor that emits laser light as shown by dashed line <NUM>. One or more first reflected beams <NUM> of the emitted light are directed toward and reflect off of the first mirror <NUM>. The first reflected beams <NUM> are then redirected as second reflected beams <NUM> by the second mirror <NUM>. The second reflected <NUM> may be directed toward a blind spot or other area around the vehicle.

Light received from the environment, as shown by dotted line <NUM>, is reflected off of second mirror <NUM> and directed toward the first mirror <NUM> as first reflected beam <NUM>. Then the first reflected beam <NUM> is directed toward and reflected off of the first mirror <NUM> and towards the sensor, as shown by dotted line <NUM>. As noted above, in operation each mirror may be used to emit and/or receive laser light (or RF waves or optical imagery). <FIG> illustrates a perspective view <NUM> of the scenario, showing a mirror reflecting the beam (or radio waves) towards and from a blind spot along the rear of the vehicle. Shorter dashed lines <NUM> illustrate emitted beams (or radio waves) that are not reflected by the mirror but which may be blocked by a portion of the vehicle (e.g., a surface of the trailer). While only first and second mirrors are shown in this example, one or more additional mirrors may also be employed. In this scenario, the mirrors <NUM> and/or <NUM> may be rigidly affixed or otherwise permanently positioned to a surface of the vehicle. Alternatively, as with mirrors <NUM>, the mirrors <NUM> and/or <NUM> may be configured to pop up or otherwise extend from the vehicle during use, and retract onto or into the vehicle when not in use. In one scenario, such pop-up mirrors could be used on an as-needed basis, for instance in response to detection of a blind spot or a change in the size of a blind spot.

And <FIG> illustrate yet another scenario <NUM> using a mirror <NUM> that extends from the sensor housing, e.g., via an extendable or maneuverable arm <NUM>. In this example, the sensor may be a lidar sensor that emits laser light as shown by dashed line <NUM>. One or more beams of the emitted light are directed toward and reflect off of the mirror <NUM>. The reflected beams, shown by dashed line <NUM>, may be directed toward a blind spot or other area around the vehicle. Light received from the environment, as shown by dotted line <NUM>, is reflected off of the mirror <NUM> and directed toward the sensor, as shown by dotted line <NUM>. In operation, the mirror <NUM> may be used to emit and/or receive laser light (or RF waves, optical or infrared imagery, etc.). <FIG> illustrates a perspective view <NUM> of the scenario, showing a mirror reflecting the beam (or radio waves) towards and from a blind spot along the rear of the vehicle. Shorter dashed lines <NUM> illustrate emitted beams (or radio waves) that are not reflected by the mirror but which may be blocked by a portion of the vehicle (e.g., a front or side surface of the trailer).

Any combination of mirror configurations according to the above examples may be employed according to aspects of the technology.

<FIG> illustrate another example that shows an enhancement to the sensor's FOV by reducing a blind spot. <FIG> illustrates a first scenario <NUM> with passenger vehicle having a rooftop sensor with a FOV <NUM>. Arrow <NUM> represents the lower limit of the FOV, for instance due to a corner or other portion of the vehicle. As seen in this rear view, a blind spot <NUM> is adjacent to a side of the vehicle. <FIG> illustrates a second scenario <NUM>. In this scenario, the base FOV <NUM> can be enhanced with an added FOV <NUM> via mirror <NUM>. As a result, blind spot <NUM> can be made much smaller than initial blind spot <NUM> (or eliminated entirely).

<FIG> illustrate a further example <NUM>. Here, as shown in <FIG>, a first vehicle <NUM> may be waiting at a stop light. Another vehicle, such as a cargo truck <NUM>, may stop behind the first vehicle <NUM>. Due to the size of the truck, the first vehicle may be partly or entirely obscured from view for a vehicle positioned behind the truck. For instance, <FIG> illustrates a third vehicle <NUM>, e.g., a passenger vehicle such as a sedan or minivan, having a sensor FOV <NUM>. Here, any of the mirror configurations described above may be employed to redirect laser light (or RF waves, optical or infrared imagery, etc.) to enhance the sensor's FOV, as shown by dotted line <NUM>.

The mirrors may be front surface mirrors (with the reflective surface being above a backing), and may be flat. There should be minimal or no refraction effect in a secondary (e.g., rear) surface of the mirror. Each mirror can be of any size or shape. For instance, a mirror may be rectangular, circular or oval in shape, and range in size from a few square centimeters to one square meter or more. In one scenario, the size of a mirror may be the FOV range times the distance from the lidar to the mirror. Given both values are typically small, the size of mirror may be in tens of centimeters. If multiple mirrors are used, they do not need to be the same size.

Various issues may impact the quality of the information provided by employing redirecting mirrors. For instance, the size, shape and/or distance of the mirror from the sensor impacts the size or resolution of the objects that can the detected. Wind drag, vibration, bugs, dirt, condensation, frost and other factors may also affect the quality of the received information. Thus, a cleaning system may be employed to remove or reduce debris. The cleaning system may include a heater element to eliminate condensation or frost.

As noted above, multiple mirrors may be employed to redirect the beams. This could be done with either coplanar mirrors or non-coplanar mirrors. Vibration and other issues may be more pronounced when there are multiple mirrors involved. A calibration system (e.g., using cameras) could account for mirror movement due to vibration or wind drag.

For instance, an onboard camera of the perception system or other system of the vehicle can be used to measure the angular position of the mirror constantly during operation. Information about the mirror's angular position may be employed as part of a mirror reflection model, which is used in an overall sensor calibration process.

In one scenario, the calibration process determines an extrinsic matrix C. Here, the vehicle may drive for several miles (or more or less), collecting a series of data (e.g., pose and a lidar point set). Then the system solves for the extrinsic matrix C so that when transforming every lidar point set to the world coordinate system, different lidar point sets should be well aligned at overlapped parts. In order to help determine the extrinsic matrix C, small fiducial markers could be added on or incorporated into the mirror surface that can be seen in a small portion of the laser beams hitting the mirror. The measurements from the markers can used to accurately determine the position and orientation relative to sensor. For any laser point p in the laser framework. C * p is its coordinates in the world coordinate system. For laser points that are reflected, a reflection matrix Ri (i is the index of mirror) is needed so that for any reflected laser point p in the laser framework, Ri * p is its real position in the laser framework. Therefore, for all the reflected laser point p in the laser framework, C * Ri * p is its real position in the world coordinate system.

There are two ways of computing (C * Ri), which is the extrinsic matrix for reflected laser points. One way treats the approach as a normal calibration task, but selects out only reflected points. In this way, the system can directly determine C * Ri. In the other way, the system measures all necessary geometry information of the vehicle and the mirror, e.g. normal direction, positions of the laser and the mirror. Ri is computed based on this measured information. For instance, given the pose of the vehicle and the extrinsic matrix, the system can compute a transform matrix T which transforms any laser point in the lidar local coordinate system to the world system (lat/long or smooth coordinates). T = L * C, where L is a localization matrix, and C is the extrinsic matrix. L changes with the vehicle pose, while C is a constant matrix which the calibration process is aiming at.

To simplify the process, when calibrating the extrinsic matrix for reflected points, the system may only need to collect the lidar points shot into the mirror, and feed that information into the process described above.

In some scenarios, a non-planer mirror could be employed to detect whether there is an object in a general vicinity, although it may be difficult to determine exactly where the object is or the particular type of object. For instance, this might approach may be beneficial with a detector located on the underside of the vehicle, which can be used to determine that a region beneath or adjacent to the vehicle is clear before the vehicle starts moving. In one scenario, one or more mirrors may be curved. For example, a convex mirror may be used to expand the field of view and a concave mirror to contract the field of view. For a non-flat (e.g., convex or concave) mirror, the calibration system would calibrate the returned signal from different points on the mirror individually. For instance, a look-up table may be created for laser points reflected from different spots on the mirror. This is similar to storing a high resolution mesh of the mirror surface and computing the reflection transform for each single laser point.

<FIG> illustrates an example operational method <NUM> for a vehicle configured to operate in an autonomous driving mode according to the above techniques. As shown in block <NUM>, the method includes receiving obtained sensor data from one or more sensors. One or more processors of the vehicle's control system are configured to receive the obtained sensor data. The sensors may be part of a perception system of the vehicle, and are configured to detect objects in an environment surrounding the vehicle. Each of the sensors is disposed in a respective housing positioned along the vehicle and has a respective field of view. In one example, multiple sensors may be included in the same housing, while in another example different sensors each have their own housing.

At block <NUM>, reflected signals are received from one or more mirrors remote from the respective housings of the one or more sensors. The mirrors are configured to reflect received signals towards at least one of the one or more sensors to provide an enhanced a sensor field of view. See, e.g., <FIG>, including dotted line <NUM>. Then, at block <NUM>, a driving system of the vehicle is controlled when operating in the autonomous driving mode. For instance, the processor(s) of the control system may cause the driving system to perform one or more operations in response to the received obtained sensor data and the received reflected signals that provide the enhanced sensor field of view. This may include, e.g., altering a current trajectory of the vehicle by turning or changing lanes, increasing or decreasing speed, performing emergency braking, modifying a planned route, etc..

The above approaches enable the onboard computer system to evaluate lidar and other signals reflected off of one or more mirrors external to a sensor housing. The reflected signals can enhance sensor FOV and reduce blind spots around the vehicle. Such information can be used by the computer system to effectively control the vehicle (e.g., via a planner module of the computer system), for instance by modifying a driving operation, changing a route, or taking other corrective action. Using mirrors in the manners described above enables perception to be more complete and increases the utility of sensors (e.g., more FOV for the same cost). It also allows sensors to be mounted in a potentially better location (e.g., out of harsh areas and other places that may be subject to impact from dirt, debris, etc.). Such approaches also permit the system to redirect and utilize sensor measurements of a spinning laser when it sweeps through areas that does not need sensing, e.g. sensor backside that faces the vehicle, returns from the vehicle or trailer body, and the like.

Claim 1:
A vehicle (<NUM>; <NUM>; <NUM>) configured to operate in an autonomous driving mode, comprising:
a driving system including a steering subsystem (<NUM>), an acceleration subsystem (<NUM>) and a deceleration subsystem (<NUM>) to control driving of the vehicle (<NUM>; <NUM>; <NUM>) in the autonomous driving mode;
a perception system (<NUM>) including one or more sensors (<NUM>) configured to detect objects in an environment surrounding the vehicle (<NUM>; <NUM>; <NUM>) based on obtained sensor data, each of the one or more sensors (<NUM>) being disposed in a respective housing positioned along the vehicle (<NUM>; <NUM>; <NUM>);
one or more mirrors (<NUM>) remote from the respective housings of the one or more sensors, the one or more mirrors (<NUM>) being configured to reflect received signals (<NUM>, <NUM>) towards at least one of the one or more sensors (<NUM>) to enhance a sensor field of view; and
a control system operatively connected to the driving system and the perception system (<NUM>), the control system having one or more computer processors (<NUM>) configured to receive sensor data corresponding to the enhanced sensor field of view from the perception system (<NUM>) and to direct the driving system when operating in the autonomous driving mode based on the sensor data received from the perception system (<NUM>),
wherein the vehicle is configured to control operation of at least one of the one or more mirrors by dampening vibration of the at least one mirror.