Patent Publication Number: US-11643154-B2

Title: Systems and methods for automatic air and electrical connections on autonomous cargo vehicles

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation-in-part of U.S. patent application Ser. No. 15/992,337, filed May 30, 2018, the entire disclosure of which is incorporated herein by reference. 
    
    
     BACKGROUND 
     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. 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. For conventional non-autonomous commercial tractor-trailer vehicles, the air supply that controls the trailer brakes and the electrical connector that controls lights and power automatic braking system units are connected and disconnected manually. Since such vehicles are driven manually, the driver typically performs the tasks of coupling and decoupling the air supply and electrical connectors between the tractor unit and the trailer. 
     However, this approach may not be feasible for large cargo vehicles that will operate in a partially or fully autonomous driving mode. In the former situation, the passenger in the cab of the tractor unit may not be appropriately trained to couple or decouple the trailer to the trailer unit. And in the latter situation, there may be no person present at either the cargo pickup location or the destination. Thus, the connection process, whether coupling or decoupling, may be a major barrier for large autonomous cargo vehicles. One solution would be to have a person on hand at both endpoint facilities, although this may be inefficient or simply not feasible in various situations. 
     BRIEF SUMMARY 
     The technology described herein provides systems and methods for autonomously coupling and decoupling the air supply and electrical connections between the vehicle cab and the cargo trailer. Aspects of the technology include fifth-wheel and kingpin configurations to provide these connections. Methods of coupling and decoupling using various sensors and automated landing gear are also disclosed. 
     According to aspects of the disclosure, a vehicle is configured to operate in an autonomous driving mode. The vehicle comprises a tractor unit that includes a driving system configured to perform driving operations in the autonomous driving mode, a perception system including one or more sensors configured to detect objects in an environment surrounding the vehicle, and a fifth-wheel configured to detachably couple to a kingpin of a trailer. The fifth-wheel includes a clamp mechanism and a connection surface. The clamp mechanism is arranged to secure to a clamp section of the kingpin. The connection surface includes a pneumatic connection section and an electrical connection section. The pneumatic connection section includes one or more slots arranged along the connection surface to align with one or more holes on a contact surface of the kingpin. The one or more slots are configured to provide air pressure to a braking system of the trailer. The electrical connection section includes a set of electrical contacts configured for operative communication with an electrical contact interface of the kingpin. The tractor unit also includes a control system that is operatively coupled to the driving system, the perception system and the fifth-wheel. The control system has one or more computer processors configured to receive data from the perception system, to direct the driving system when operating in the autonomous driving mode based on the data received from the perception system, and to control communication with the trailer via the set of electrical contacts of the fifth-wheel. 
     In one example, the one or more slots are concentric circular slots arranged along the connection surface. In another example, the one or more slots are arcuate slots arranged along the connection surface. 
     The pneumatic connection section of the fifth-wheel may further include one or more internal pneumatic conduits respectively coupled at a first end to the one or more slots and at a second end to an air supply of the vehicle, as well as an electrical harness coupled at a first end thereof to the electrical contacts of the electrical connection section. The electrical harness is operatively connected via a second end thereof to the control system. 
     In another example, the electrical connection section is further configured to supply power to the trailer. 
     The fifth-wheel may further include one or more read heads configured to obtain rotational information from a magnetic encoder ring of the kingpin and to provide the obtained rotational information to the control system in order to determine a relative alignment of the trailer to the tractor unit. Here, the electrical connection section may be arranged centrally along the connection surface of the fifth-wheel, the one or more slots may be arranged at least partially around the connection section, and the one or more read heads may be disposed either (i) between the one or more slots and the electrical connection section, or (ii) external to the one or more slots along the connection surface. The one or more read heads may comprise a pair of read heads. In this case, each read head may separately coupled to a power system of the vehicle and having a different communication link to the control system, for example for redundancy. 
     The one or more sensors of the perception system may include at least one sensor positioned on the tractor unit to identify a relative position of the trailer to the tractor unit so that the fifth-wheel can be aligned to capture the kingpin. 
     And in a further example, the vehicle includes the trailer, and the fifth-wheel is coupled to the kingpin of the trailer. 
     According to other aspects of the technology, a trailer is configured to operate with a tractor unit in an autonomous driving mode. The trailer comprises a cargo unit having a support platform, a plurality of wheels coupled to the support platform, a braking system operatively attached to one or more of the plurality of wheels, an electronic control unit comprising one or more processors, and a kingpin. The kingpin has a first end attached to the support platform, a second end remote from the first end, and a clamp section disposed between the first end and the second end. The clamp section is configured for pivotal connection to a clamp mechanism of a fifth-wheel of the tractor unit. The kingpin includes one or more air conduits and an electrical conduit disposed therein. The first end of the kingpin includes one or more connectors respectively coupled to the one or more air conduits and an electrical connector coupled to the electrical conduit. The second end of the kingpin includes one or more openings corresponding to the air conduits, the one or more openings being arranged to receive air pressure from the tractor unit and supply the air pressure to the braking system via the air conduits. The second end of the kingpin further includes an electrical contact interface configured for operative communication with an electrical connection section of the fifth-wheel to provide signals to the electronic control unit via the electrical conduit for operation in the autonomous driving mode. 
     In one example, the second end of the kingpin includes a set of O-rings disposed on either side of the one or more openings. The set of O-rings is configured to prevent air leakage when the kingpin is coupled to the fifth-wheel. In another example, the electrical contact interface of the second end of the kingpin comprises one or more slip-ring electrical connections coupled to the electrical conduit. Here, the one or more slip-ring electrical connections include a set of contact patches. The set of contact patches are arranged to line up with electrical contacts on the fifth-wheel. 
     The electrical contact interface may be further configured to receive power from the electrical connection section of the fifth-wheel and to supply the power to the electronic control unit of the trailer. 
     The second end of the kingpin may further include a magnetic encoder ring arranged to provide rotational information of the kingpin to one or more read heads disposed at the fifth-wheel of the tractor unit. In this case, the electrical contact interface may be arranged centrally along the second end of the kingpin, the one or more openings may be arranged closer to an outer edge of the second end than the electrical contact interface, and the magnetic encoder ring may be disposed either (i) between the electrical contact interface and the one or more openings, or (ii) closer to the outer edge of the second end than the one or more openings. The magnetic encoder ring may include a set of unique marks or distance coded reference marks to indicate the rotational information. 
     The trailer may further comprise a connection section including one or more air connections and an electrical connection. The connection section is configured to provide backward compatibility with a tractor unit not capable of operating in an autonomous driving mode. The trailer may further include one or more check valves. In this case, each check valve has a first link to a respective one of the one or more air connections of the connection section, a second link to a respective one of the one or more air conduits of the kingpin, and a third link to the braking system. Here, the electronic control unit is operatively coupled to the electrical connection of the connection section. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS.  1 A-B  illustrate an example tractor-trailer arrangement. 
         FIG.  1 C  illustrates a portion of a trailer of the tractor-trailer arrangement of  FIGS.  1 A-B . 
         FIGS.  1 D-E  illustrate tractor-trailer connection arrangements according to aspects of the disclosure. 
         FIGS.  1 F-G  illustrate an example fifth-wheel according to aspects of the disclosure. 
         FIG.  2 A  illustrates a system diagram of an autonomous vehicle control system in accordance with aspects of the disclosure. 
         FIG.  2 B  illustrates a system diagram of a trailer, in accordance with aspects of the disclosure. 
         FIGS.  3 A-B  illustrate an example trailer kingpin in accordance with aspects of the disclosure. 
         FIGS.  4 A-D  illustrate features of a tractor fifth-wheel, in accordance with aspects of the disclosure. 
         FIGS.  5 A-C  illustrate a contactless angle sensor arrangement in accordance with aspects of the disclosure. 
         FIG.  6    illustrates a backward-compatible trailer hookup arrangement in accordance with aspects of the disclosure. 
         FIG.  7 A  is an example of short and long range Lidar coverage for a tractor-trailer vehicle in accordance with aspects of the disclosure. 
         FIG.  7 B  is an example of radar or camera coverage for a tractor-trailer vehicle in accordance with aspects of the disclosure. 
         FIGS.  8 A-C  illustrate examples of rear sensor units in accordance with aspects of the disclosure. 
         FIGS.  9 A-B  illustrate examples of rear sensor coverage in accordance with aspects of the disclosure. 
         FIG.  10    illustrates an example of autonomous hitching of a tractor unit to a trailer in accordance with aspects of the disclosure. 
         FIGS.  11 A-C  illustrate relative positioning of the kingpin and fifth-wheel in accordance with aspects of the disclosure. 
         FIG.  12    illustrates a method of coupling a tractor unit to a trailer in accordance with aspects of the disclosure. 
         FIG.  13    illustrates a method decoupling a tractor unit from a trailer in accordance with aspects of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Overview 
     The technology relates to fully autonomous or semi-autonomous vehicles for transporting cargo, such as freight or livestock, between selected locations. The cargo may be transported using a towed or trailered arrangement. Driving from a warehouse or other point of origin to the destination is done in a fully or partially autonomous mode. Whether the cargo unit (trailer) can be autonomously coupled and decoupled with a tractor unit may significantly impact how efficient the overall transportation process will be. 
       FIGS.  1 A-B  illustrate an example vehicle  100 , 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  4  through  8 . As shown, the truck includes a tractor unit  102  and a single cargo unit or trailer  104 . The trailer  104  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  102  includes the engine and steering systems (not shown) and a cab  106  for a driver and any passengers. In a fully autonomous arrangement, the cab  106  may not be equipped with seats or manual driving components, since no person may be necessary. 
     The trailer  104  includes a hitching point, known as a kingpin,  108 . The kingpin  108  is typically formed as a solid steel shaft, which is configured to pivotally attach to the tractor unit  102 . In particular, the kingpin  108  attaches to a trailer coupling  110 , 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, connectors  112  and  114  also couple from the tractor unit  102  to the trailer  104 . These may include one or more air hoses  112  and one or more electrical conduits  114 . The air hose(s)  112  enable the tractor unit  102  to operate the pneumatic brakes of the trailer  104 , and the electrical conduit(s)  114  provide power and signals to the brakes and lights of the trailer  104 . In an autonomous system, it may be difficult or unfeasible to manually connect the air hoses, electrical conduits and other connectors between the tractor unit  102  and trailer  104 . 
       FIG.  1 C  is a partial view of trailer  104 , and illustrates an example kingpin  108 . As shown, the kingpin  108  has a first end  116  that is secured to a bottom of the trailer structure. A second end  118  of the kingpin  108  is configured to pivotally couple to the fifth-wheel  110 , (see  FIGS.  1 D and  1 E ). The trailer structure also includes landing gear  120 . While only one landing gear element is shown, two (or more) landing gear may be employed. When the trailer  104  is connected to the tractor unit  102 , the landing gear  120  are retracted so that they do not interfere with driving, as shown in  FIG.  1 D . When the trailer  104  is to be disengaged from the tractor unit  102 , the landing gear  120  are extended to contact the ground and support the trailer structure, as shown in  FIG.  1 E . 
     Also shown in  FIG.  1 C  is a connection section  122 , which receives the air hoses  112 , electrical conduit(s)  114  and any other connectors from the tractor unit  102 . In order to overcome issues involved with such manual connections, a new approach has been designed that helps achieve full end-to-end autonomous operation while providing secure, reliable and backward compatible connectivity. This approach is discussed further below. 
       FIGS.  1 F and  1 G  illustrate an example of fifth-wheel  110  in accordance with aspects of the technology. As shown, the fifth-wheel includes a clamp mechanism  124  that may comprise a pair of adjustable locking elements. A pair of angled ramps  126  and a channel  128  formed between the ramps allow the kingpin  108  to be guided towards the clamp mechanism  124 . Once the kingpin  108  is received by the clamp mechanism  124 , the kingpin  108  is secured but permitted to pivotally rotate, which allows for the tractor unit  102  to turn at an angle relative to the trailer  104 . 
     In a transportation arrangement where the tractor unit is capable of driving in a fully autonomous or semi-autonomous mode, there may be no driver or other person available to hook up the trailer to the tractor unit at a pickup location or to disconnect them at the destination. For instance, how would the air hoses  112  and the electrical conduits  114  be connected to the connection section  122 ? Aspects of the technology overcome these and other issues by omitting external air hoses, electrical conduits and other connections made between a back of the cab and the front of the trailer. Instead, the necessary connections are made internally through the fifth-wheel and the kingpin. This approach and other features are detailed below. 
     Example Systems 
       FIG.  2 A  illustrates a block diagram  200  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. The U.S. 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 0 has no automation and the driver makes all driving-related decisions. The lowest semi-autonomous mode, Level 1, includes some drive assistance such as cruise control. Level 2 has partial automation of certain driving operations, while Level 3 involves conditional automation that can enable a person in the driver&#39;s seat to take control as warranted. In contrast, Level 4 is a high automation level where the vehicle is able to drive without assistance in select conditions. And Level 5 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 1-5, 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.  2 A , the vehicle includes a control system of one or more computing devices, such as computing devices  202  containing one or more processors  204 , memory  206  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  206  stores information accessible by the one or more processors  204 , including instructions  208  and data  210  that may be executed or otherwise used by the processor  204 . The memory  206  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, 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 instructions  208  may be any set of instructions to be executed directly (such as machine code) or indirectly (such as scripts) by the processor. For example, the instructions may be stored as computing device code on the computing device-readable medium. In that regard, the terms “instructions” and “programs” may be used interchangeably herein. The instructions may be stored in object code format for direct processing by the processor, or in any other computing device language including scripts or collections of independent source code modules that are interpreted on demand or compiled in advance. The data  210  may be retrieved, stored or modified by one or more processors  204  in accordance with the instructions  208 . As an example, data  210  of memory  206  may store information, such as calibration information, to be used when calibrating different types of sensors. 
     The one or more processor  204  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. Although  FIG.  2 A  functionally illustrates the processor(s), memory, and other elements of computing devices  202  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  206  may be a hard drive or other storage media located in a housing different from that of the processor(s)  204 . 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  202  may form an autonomous driving computing system incorporated into vehicle  100 . The autonomous driving computing system may capable of communicating with various components of the vehicle. For example, returning to  FIG.  2 A , the computing devices  202  may be in communication with various systems of the vehicle, including a driving system including a deceleration system  212  (for controlling braking of the vehicle), acceleration system  214  (for controlling acceleration of the vehicle), steering system  216  (for controlling the orientation of the wheels and direction of the vehicle), signaling system  218  (for controlling turn signals), navigation system  220  (for navigating the vehicle to a location or around objects) and a positioning system  222  (for determining the position of the vehicle). 
     The computing devices  202  are also operatively coupled to a perception system  224  (for detecting objects in the vehicle&#39;s environment), a power system  226  (for example, a battery and/or gas or diesel powered engine) and a transmission system  230  in order to control the movement, speed, etc., of vehicle  100  in accordance with the instructions  208  of memory  206  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  228  are coupled to the transmission system  230 , and the computing devices  202  may be able to receive information about tire pressure, balance and other factors that may impact driving in an autonomous mode. 
     The computing devices  202  may control the direction and speed of the vehicle by controlling various components. By way of example, computing devices  202  may navigate the vehicle to a destination location completely autonomously using data from the map information and navigation system  220 . Computing devices  202  may use the positioning system  222  to determine the vehicle&#39;s location and the perception system  224  to detect and respond to objects when needed to reach the location safely. In order to do so, computing devices  202  may cause the vehicle to accelerate (e.g., by increasing fuel or other energy provided to the engine by acceleration system  214 ), decelerate (e.g., by decreasing the fuel supplied to the engine, changing gears, and/or by applying brakes by deceleration system  212 ), change direction (e.g., by turning the front or other wheels of vehicle  100  by steering system  216 ), and signal such changes (e.g., by lighting turn signals of signaling system  218 ). Thus, the acceleration system  214  and deceleration system  212  may be a part of a drivetrain or other transmission system  230  that includes various components between an engine of the vehicle and the wheels of the vehicle. Again, by controlling these systems, computing devices  202  may also control the transmission system  230  of the vehicle in order to maneuver the vehicle autonomously. 
     As an example, computing devices  202  may interact with deceleration system  212  and acceleration system  214  in order to control the speed of the vehicle. Similarly, steering system  216  may be used by computing devices  202  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  216  may include components to control the angle of wheels of the tractor unit  102  to turn the vehicle. Signaling system  218  may be used by computing devices  202  in order to signal the vehicle&#39;s intent to other drivers or vehicles, for example, by lighting turn signals or brake lights when needed. 
     Navigation system  220  may be used by computing devices  202  in order to determine and follow a route to a location. In this regard, the navigation system  220  and/or data  210  may store map information, e.g., highly detailed maps that computing devices  202  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  224  also includes one or more 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  224  may include one or more light detection and ranging (Lidar) sensors, sonar devices, radar units, cameras, inertial sensors (e.g., gyroscopes or accelerometers), and/or any other detection devices that record data which may be processed by computing devices  202 . The sensors of the perception system  224  may detect objects and their characteristics such as location, orientation, size, shape, type (for instance, vehicle, pedestrian, bicyclist, etc.), heading, and speed of movement, etc. The raw data from the sensors and/or the aforementioned characteristics can sent for further processing to the computing devices  202  periodically and continuously as it is generated by the perception system  224 . Computing devices  202  may use the positioning system  222  to determine the vehicle&#39;s location and perception system  224  to detect and respond to objects when needed to reach the location safely. In addition, the computing devices  202  may perform calibration of individual sensors, all sensors in a particular sensor assembly, or between sensors in different sensor assemblies. 
     As indicated in  FIG.  2 A , the perception system  224  includes one or more sensor assemblies  232 . In one example, the sensor assemblies  232  may be arranged as sensor towers integrated into the side-view mirrors on the truck, farm equipment, construction equipment or the like. Sensor assemblies  232  may also be positioned at different locations on the tractor unit  102  or on the trailer  104 . The computing devices  202  may communicate with the sensor assemblies located on both the tractor unit  102  and the trailer  104 . Each assembly may have one or more types of sensors such as those described above. 
     Also shown in  FIG.  2 A  is a coupling system  234  for connectivity between the tractor unit and the trailer. The coupling system  234  includes a fifth-wheel  236  at the tractor unit and a kingpin  238  at the trailer. These elements and the coupling system  234  are discussed in detail below. Most or all of the components and subsystems of  FIG.  2 A  may be part of or controlled by the tractor unit, except for the kingpin  238  of the trailer. 
       FIG.  2 B  illustrates an example block diagram  240  of the trailer. As shown, the system includes an ECU  242  of one or more computing devices, such as computing devices containing one or more processors  244 , memory  246  and other components typically present in general purpose computing devices. The memory  246  stores information accessible by the one or more processors  244 , including instructions  248  and data  250  that may be executed or otherwise used by the processor(s)  244 . The descriptions of the processors, memory, instructions and data from  FIG.  2 A  apply to these elements of  FIG.  2 B . 
     The ECU  242  is configured to receive information and control signals from the trailer unit. The on-board processors  244  of the ECU  242  may communicate with various systems of the trailer, including a deceleration system  252  (for controlling braking of the trailer), signaling system  254  (for controlling turn signals), and a positioning system  256  (for determining the position of the trailer). The ECU  242  may also be operatively coupled to a perception system  258  (for detecting objects in the trailer&#39;s environment) and a power system  260  (for example, a battery power supply) to provide power to local components. Some or all of the wheels/tires  262  of the trailer may be coupled to the deceleration system  252 , and the processors  244  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  252 , signaling system  254 , positioning system  256 , perception system  258 , power system  260  and wheels/tires  262  may operate in a manner such as described above with regard to  FIG.  2 A . 
     The trailer also includes a set of landing gear  264 , as well as a coupling system  266 . The landing gear provide a support structure for the trailer when decoupled from the tractor unit. The coupling system  266 , which may be a part of coupling system  234 , provides connectivity between the trailer and the tractor unit. The coupling system  266  may include a connection section  268  to provide backward compatibility with legacy trailer units that may or may not be capable of operating in an autonomous mode. The coupling system includes a kingpin  270  configured for enhanced connectivity with the fifth-wheel of an autonomous-capable tractor unit. These elements are discussed in detail below. 
     Example Implementations 
     In view of the structures and configurations described above and illustrated in the figures, various implementations will now be described. 
     Backward compatible with existing kingpins and trailers, the coupling system  234  provides the necessary pneumatic, power, communication, and other connections between the tractor unit and the trailer of the vehicle. As noted above, such connections can be made internally through the fifth-wheel  236  of the tractor unit and the kingpin  238  of the trailer. For instance, this may be accomplished via one or more connection conduits. An example  300  of a kingpin having internal pneumatic and electrical connections is shown in  FIGS.  3 A  and  3 B. A first end  302  of the kingpin is attached to the underside of a trailer (not shown). A clamp section  304  is disposed between the first end  302  and a second end  306 . The clamp section  304  is configured to be securely and rotatably grasped by the clamp mechanism of the fifth-wheel, such as clamp mechanism  124  shown in  FIGS.  1 F and  1 G . 
     In the side view of  FIG.  3 A , air conduits  308  and  310 , and electrical conduit  312  are illustrated in dashed lines, indicating that the conduits are received within the outer housing of the kingpin body. The air conduits provide air to a pneumatic braking system of the trailer. The air conduits may be formed by machining, casting, printing or otherwise forming channels within the kingpin between the first end  102  and the second end  104 . Connectors  314 , such as National Pipe Thread (NPT) taps, are arranged along the first end  102  to route air to the trailer&#39;s braking system. The electrical conduit  312  may provide power as well as control signal, data communication and other information to the ECU of the trailer. 
       FIG.  3 B  is a bottom view of the kingpin, illustrating an outer surface of the second end  306 . As shown, a pair of holes  316  and  318  is formed in the outer surface. These holes are at the ends of the air conduits  308  and  310 , respectively. The holes  316  and  318  are configured to line up with pressurized air slots on the trailer side, which are shown in  FIGS.  4 A-C  and are discussed below. A series of concentric O-rings  320 , illustrated in dashed lines, allow for rotation of the kingpin relative to the fifth-wheel, while also enabling the pressurized air slots to transmit pressure to the holes  316  and  318  without leaking. 
     An electrical contact interface  322  is provided as well, for instance closer to the center of the outer surface of the second end  306  than the O-rings  320  and the holes  316  and  318 . The electrical contact interface  322  may include one or more slip-ring electrical connections to couple with the electrical conduit  312 . In one example, a set of annular or arcuate contact patches are disposed along the outer surface of the kingpin base. The patches are configured to line up with contact pins on the fifth-wheel (see  FIGS.  4 A-B ), and allow for rotation of the kingpin relative to the fifth-wheel while maintaining an electrical connection. The electrical contact interface  322  may also supply power to the trailer. Other types of connections may be employed by the electrical contact interface  322 , so long as communication is enabled with the ECU. For example, inductive coupling between the fifth-wheel and the kingpin may be employed for communication, and possibly power transfer as well. 
       FIGS.  4 A-D  illustrate elements of a fifth-wheel that provide for counterpart connectivity to the kingpin of  FIGS.  3 A-B .  FIG.  4 D  presents a top-down view of a fifth-wheel, including a connection section  400  is located beneath the clamp mechanism. The connection section  400  is arranged for operative communication with the second end of the kingpin. As shown in the examples of  FIGS.  4 A and  4 B , the connection section  400  has a top surface, which is generally planar and circular, and has effectively the same diameter as the diameter of the second end of the kingpin. 
     When the kingpin is secured by the clamp mechanism, the top surface of the connection section and the outer surface of the second end of the kingpin physically contact. For instance, at least a portion of the fifth-wheel physically contacts the kingpin. As illustrated in  FIG.  4 A , the top surface of the connection section may include a pair of concentric annular slots  402  and  404 . The slots  402  and  404  are spaced to line up with the holes  316  and  318  in the second end of the kingpin, so that they can provide air pressure to the trailer. As noted above, the O-rings on the second end of the kingpin prevent air leakage. Alternatively or in addition, O-rings may also be disposed on the fifth-wheel top surface. 
     Located centrally on the top surface is an electrical connection section  408 . The electrical connection section  408  may include a set of electrical contacts  410 . Or, alternatively, the electrical connection section  408  may provide communication, signaling and/or power via inductive coupling or some other technique.  FIG.  4 B  illustrates an alternate variation where instead of annular slots, a pair of arcuate slots  412  and  414  is provided. In one scenario, the arcuate slots may be employed instead of the annular slots because the kingpin and trailer are incapable of rotating 360° with respect to the tractor unit, and so the holes  316  and  318  on the bottom of the kingpin are limited to certain contact paths on the fifth-wheel. For instance, the range of rotation may be no more than 270°. 
       FIG.  4 C  illustrates a side cutaway view of the connection section  400 . The cutaway view illustrates internal routing of air lines and an electrical harness. In particular, the slots  402  (or  412 ) and  404  (or ( 414 ) on the top surface couple to conduits  416  and  418 . The conduits  416  and  418  connect to connectors  420  and  422 , respectively, which may be NPT taps. The connectors  420  and  422  couple to the air supplies on the tractor. Similarly, electrical harness  424  connects to the electrical connection section  408  on one end and to the tractor unit ECU, which may include the computing devices and other subsystems of the tractor unit. 
     When a trailer is connected to a tractor unit, it will be very helpful for the tractor unit to know the current orientation and position of the trailer. In one scenario, this information may be obtained using sensors including Lidar, radar, cameras, sonar, etc., mounted on the tractor unit. However, adding additional sensors to obtain the information or expending processing time and resources to analyze the information from such sensors may be prohibitive. For example, there may be disadvantages in terms of cost, reliability and accuracy. Therefore, an alternative approach uses information provided directly from the kingpin and fifth-wheel themselves. 
     According to one aspect of the technology, a magnetic encoder system may be employed on the kingpin and fifth-wheel to provide information regarding the relative alignment between the tractor unit and the trailer.  FIG.  5 A  illustrates a kingpin with a contactless magnetic encoder ring  500 . The fifth-wheel, as shown in the top view of  FIG.  5 B  and cutaway view of  FIG.  5 C , includes two (or more) read heads  502 . 
     The read heads, which may be part of or operatively connected to the positioning system, obtain rotational information from magnetic signal measurements of the encoder ring. The encoder ring may include a set (e.g., a series) of unique marks or distance coded reference marks (DCRMs). The read heads are configured to detect the marks, which are used to determine the relative rotation between the kingpin and the fifth-wheel. While a single read head may be used, the additional read head(s) is included for redundancy. For instance, each read head may be powered separately and have a different communication link with the positioning system ( 222  of  FIG.  2 A ) or other elements of the tractor unit&#39;s processing system. 
     The magnetic encoder ring as shown is an axial ring of a ferrous material applied to or embedded in the second end of the kingpin. In one example, the axial ring is slightly recessed (e.g., 1-5 mm recessed) relative to the exterior surface of the second end of the kingpin, to prevent wear during contact with the fifth-wheel. In another example, the axial ring is flush with the exterior surface. Here, the complementary section of the fifth-wheel may be slightly recessed (e.g., 1-5 mm recessed) to prevent wear. 
     The read head(s) are positioned within or on a surface of the fifth-wheel. The read heads and encoder ring may be positioned so as to not interfere with the air and electrical connections between the fifth-wheel and the kingpin. In one example, the encoder ring is disposed closer to the outer edge of the second end of the kingpin than the air holes  316  and  318  of  FIG.  3 B . In another example, the encoder ring is positioned between the air holes and the electrical contact interface  322  of  FIG.  3 B . In a further example, the encoder ring is included as part of the electrical contact interface  322 . However, it may be more desirable for the encoder ring to be as large as possible, so as to give the greatest angular accuracy. The diameter of a conventional kingpin is 2 inches (50.8 mm). Thus, in the first example, the diameter of the outer edge of the encoder ring may be between 40-48 mm, and the angular accuracy may be between 0.75° and 1.1°. In another scenario, the encoder ring is arranged to provide an angular accuracy of less than 2.0°. 
     The magnetic encoder ring may be, e.g., a vulcanized elastoferrite or other polymer. In one example, a hydrogenated nitrile butadiene rubber (HNBR) and ferrite composite can be used. Alternatively, other materials such as magnetic ceramics, which may comprise strontium carbonate and iron oxide, may be employed. Still other ferrous materials can be employed, so long as the read heads are able to pick up and measure the necessary rotational information. Also, one or more additional encoder rings of varying diameters may be disposed on the second end of the kingpin. The additional encoder ring(s) may provide redundancy. They may also provide for enhanced accuracy of the rotational position measurements, especially if there is some non-planar motion of the kingpin relative to the fifth-wheel during driving, such as pitch or roll. 
     The fifth-wheel on the autonomous mode-capable tractor unit is designed to work with both new and legacy trailers. Thus, for a new trailer with a kingpin having internal air and electrical connections, the system would be arranged as discussed above and the tractor would provide pneumatic pressure, data and other signals, and/or power to the trailer. However, for a legacy trailer with a conventional kingpin, the fifth-wheel would obviously not be able to supply air, electrical signals or power, but would still seamlessly connect to the kingpin. In this case, air hoses and electrical conduits would need to be coupled to the connection section on the trailer, such as connection section  122  of  FIG.  1 C . 
     Similarly, the new kingpin arrangement is also backward compatible with conventional fifth-wheel devices. Here, if an autonomous-mode capable trailer were coupled to a conventional tractor unit, the air hoses and electrical conduits of the tractor unit would be coupled to a backward compatible connection section on the trailer.  FIG.  6    illustrates an example  600  of such an arrangement. As shown, the arrangement includes a connection section  602 , which may be equivalent to the connection section  122  shown in  FIG.  1 C . The connection section  602  may be arranged on a front side of the trailer facing the rear of the cab of the tractor unit. The connection section is configured to receive, for example, compressed air via air connections  604 , and power, control signals, data communication and other information via electrical connection  606 . 
     The air connections  604  may separately couple to check valves  608  via air lines  610 . The check valves  608  have separate air lines  612 , which couple to connectors on the kingpin, such as connectors  314  of  FIG.  3 A . Each check valve  608  may be an “or” type check valve, which can be used to combine the two air signals coming from one or both of the air connections  604  and the connectors on the kingpin. If air pressure is present in either line, the “or” valve provides the pressure to the braking system of the trailer. In one example, the check valves are double check valves, where the higher of two sources of pressure provides the pressure to the braking system. 
     The electrical connection  606  is coupled to trailer ECU  614 , for instance via communication cable  616 . The ECU  614  is also coupled to the electrical conduit of the kingpin, such as electrical conduit  312  of  FIG.  3 A , for instance by communication cable  618 . The ECU determines whether information is being provided via either the electrical connection  606  or the electrical conduit of the kingpin, and can then act on the received information accordingly. While the ECU may be wired to the electrical connection  606  and/or the kingpin, in an alternative wireless links may be employed. For instance, these links may operate in the RF band, using a Bluetooth®, near field communication (NFC) or other communication arrangement. 
     Communication between a tractor unit and a trailer using the aforementioned electrical connections can employ different protocols. For instance, a protocol using the Controller Area Network (CAN) bus architecture, or an Ethernet-based technology such as BroadR-Reach®, may be employed between ECUs on the tractor unit and the trailer. Alternatively, other signaling approaches may also be used. By way of example only, data such as the trailer ID, trailer status, wheel speeds, location, service intervals, tire or brake pressure, inertial data, etc., may be transmitted to the tractor unit from the trailer. In addition, environmental information from sensors locally mounted on the trailer may also be provided to the tractor unit. This may include Lidar, radar, sonar, imaging and other sensor information. The imaging information may come from one or more cameras capable of visual, infrared, and/or night-vision operation. Cargo-specific information, such as the type(s) of cargo, weight, size, footprint and loading or stacking arrangement, whether it is perishable, subject to security, hazard or other safety protocols, etc., is also capable of being communicated via the CAN bus architecture or other communication arrangement. 
     In one scenario, the information from one or more different kinds of sensors may be employed so that the tractor-trailer system may operate in an autonomous mode. Each 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 50-250 meters, while the short range Lidar has a range no greater than 1-50 meters. Alternatively, the short range Lidar may generally cover up to 10-15 meters from the vehicle while the long range Lidar may cover a range exceeding 100 meters. In another example, the long range is between 10-200 meters, while the short range has a range of 0-20 meters. In a further example, the long range exceeds 80 meters while the short range is below 50 meters. Intermediate ranges of between, e.g., 10-100 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, a gyroscope, an accelerometer, etc. 
     Examples of Lidar, camera and radar sensors are shown in  FIGS.  7 A and  7 B . In  FIG.  7 A , one or more Lidar units may be located in sensor housing  702 . In particular, a pair of sensor housings  702  may be located on either side of the tractor unit cab, for instance integrated into a side view mirror assembly. In one scenario, long range Lidars may be located along a top or upper area of the sensor housings  702 . For instance, this portion of the housing  702  may be located closest to the top of the truck cab or roof of the vehicle. This placement allows the long range Lidar to see over the hood of the vehicle. And short range Lidars may be located along a bottom area of the sensor housings  702 , closer to the ground, and opposite the long range Lidars in the housings. This allows the short range Lidars to cover areas immediately adjacent to the cab. This would allow the perception system to determine whether an object such as another vehicle, pedestrian, bicyclist, etc. is next to the front 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.  7 A , the long range Lidars on the left and right sides of the tractor unit have fields of view  704 . These encompass significant areas along the sides and front of the vehicle. As shown, there is an overlap region  706  of their fields of view in front of the vehicle. A space is shown between regions  704  and  706  for clarity; however in actuality there is no break in the coverage. The short range Lidars on the left and right sides have smaller fields of view  708 . The overlap region  706  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. 
       FIG.  7 B  illustrates coverage  710  for either (or both) of radar and camera sensors on both sides of a tractor-trailer. Here, there may be multiple radar and/or camera sensors in each of the sensor housings  702 . As shown, there may be sensors with side and rear fields of view  714  and sensors with forward facing fields of view  716 . The sensors may be arranged so that the side and rear fields of view  714  overlap, and the side fields of view may overlap with the forward facing fields of view  716 . As with the long range Lidars discussed above, the forward facing fields of view  716  also have an overlap region  718 . This overlap region provides similar redundancy to the overlap region  706 , and has the same benefits should one sensor suffer degradation in performance. 
     In addition to driving in an autonomous mode using information from the sensors in the sensor housings  702 , the system also needs to couple and decouple the tractor unit and the trailer. In one scenario, the sensors of the sensor housings  702  may provide sufficient information to indicate the relative position and alignment of the tractor unit and the trailer. However, in another scenario, other sensors may be employed to provide this information.  FIGS.  8 A-C  illustrate several examples.  FIG.  8 A  is a side view of a tractor unit and a portion of a trailer to which the tractor unit will couple. As shown, one or more rear sensors  800  are provided on the back of the cab, which are used to identify the relative positioning of the trailer to the tractor unit, so that the fifth-wheel can be aligned and capture the kingpin. By way of example, the rear sensor(s)  800  may include Lidar sensors, camera sensors, or both. Other sensors may also be employed, such as sonar and/or radar. 
       FIGS.  8 B and  8 C  are top-down views of the tractor unit, with variations on the location(s) for the rear sensor(s)  800 . As shown in  FIG.  8 B , a pair of rear sensors  800  may be disposed on the left and right sides of the back of the cab. And as shown in  FIG.  8 C , one rear sensor  800  may be disposed centrally on the back of the cab. The exact position, height and orientation of the rear sensor(s)  800  may depend on the specific configuration of the cab and/or the type of trailer to be hitched to the tractor unit. 
       FIGS.  9 A and  9 B  illustrate sensor coverage. For instance, as shown in  FIG.  9 A , a pair of rear sensors may be employed. Here, fields of view  900  from side sensors mounted on the rear view mirror assemblies may not encompass the region toward the rear of the cab, and thus may not be able to provide sufficient information about the alignment of the trailer kingpin to the fifth-wheel. However, the fields of view  902  from the rear sensors do capture the necessary information, and provide an overlapping field of view  904 . This overlapping field of view  904  may provide enhanced resolution or other additional information to assist when coupling the fifth-wheel to the kingpin. And in the example of  FIG.  9 B , a single, centrally located sensor has a field of view  906 . 
     The information obtained by the rear sensors, as well as from other sensors of the system, is used by the tractor unit&#39;s processing system(s) to align the vehicle&#39;s wheels, to back up the tractor unit and to properly connect the fifth-wheel and kingpin. In one scenario, the trailer hitch includes one or more easily visible markings or beacon elements for a camera, Lidar or other sensor of the tractor unit to hone in on. This could make it easier on the perception system to find where the hitch is. By way of example, the trailer may include highly reflective strips or other retroreflectors placed in a specific manner (pattern) along the front face so that the rearward facing cameras or Lidars of the tractor unit are able to rapidly identify them and use that information to align the tractor unit to the trailer. In addition to such visual indicia, other passive elements or even active transmissive beacons, e.g., optical or infrared light emitting diodes (LEDs), or audible transmitters such as a tone generator for use with a sonar sensor at the tractor unit, may be employed. 
       FIG.  10    illustrates a situation where the tractor unit is initially not aligned with the trailer. As shown in this birds-eye view, the tractor unit may be disposed at some non-zero degree angle θ relative to the trailer. Using the sensor information, the tractor unit can, in an autonomous mode, angle the front wheels as shown by arrow  1000  to adjust the alignment closer to parallel with the trailer. And the tractor unit can also back up in the autonomous mode as shown by arrow  1002 . Once properly aligned and positioned, the coupling mechanism of the fifth-wheel engages the kingpin. At this point, the couplings between the fifth-wheel and kingpin are made and air, power and data may be provided as described above. 
     When coupling the tractor unit to the trailer, the landing gear of the trailer are positioned in a deployed state to support and stabilize the trailer. As the tractor unit approaches (e.g., backs towards) the trailer, it may be determined from sensor or other information that the kingpin is too high ( FIG.  11 A ) or too low ( FIG.  11 B ) relative to the fifth-wheel. This may occur due to a slope of the land or other environmental features. In order to ensure proper height alignment ( FIG.  11 C ) of the fifth-wheel and kingpin, the tractor unit operating in an autonomous mode may make certain adjustments. For instance, this might include changing the height of the fifth-wheel via an air suspension system. 
     Once the trailer is connected to the tractor unit, the control system (e.g.,  202  of  FIG.  2 A ) may signal to the trailer ECU to retract the landing gear so that they do not interfere with driving (see  FIG.  1 D ). Conversely, when the trailer is to be detached from the tractor unit, the ECU causes the landing gear to extend until they contact the ground (see  FIG.  1 E ). Adjustment of the landing gear may be done via electromechanical, pneumatic or hydraulic mechanisms. For instance, the landing gear can be controlled electronically by the tractor once the tractor unit and the trailer are hitched or otherwise connected as described above. This is very useful as until the landing gear are lifted or otherwise retracted, the trailer cannot be moved. Conversely, the trailer needs to have proper support before the tractor unit drives away. 
     In one example, one or more electric motors can be used to lift and lower the landing gear. However, such motors might need to be fairly large and powerful. In this case, the electrical connection between the trailer and tractor unit may not be able to support a large current draw to power the motors. Alternatively, the system could employ air power, for instance available as part of the braking system, to lift and lower the landing gear. The electrical or air-powered control of the landing gear may be accomplished as described above via the fifth-wheel and kingpin connection. These landing gear operations could be controlled electronically via valves, such as check valves  608  or equivalent valve connections, which reside on the trailer. Furthermore, even trailers that are not intended to interface with autonomous vehicles or have hitch structures as described herein may be capable of benefitting from having such air powered landing gear. 
     In addition, in one scenario once the trailer and tractor unit are coupled, the trailer is able to communicate with the tractor unit about its status. For instance, the trailer can identify faults, failures or other known conditions. The trailer can also indicate which trailer it is (e.g., with a unique reference number) or whether it is the first, second or third trailer in a tandem arrangement. Sensor and cargo information may also be provided by the trailer to the tractor unit. Sensor data such as information from on-board Lidar, radar, camera (e.g., visual, infrared, or night-vision), sonar, wheel speed sensors and the like may be transmitted, e.g., via a CAN bus or other communication arrangement as discussed herein. Similarly, information about the cargo, including cargo type(s), weight, size, footprint and stacking arrangements along the trailer, whether any cargo is perishable, subject to security or hazard protocols, etc., may be communicated to the tractor unit. 
       FIG.  12    provides an example method  1200  of coupling a tractor unit to a trailer. Per block  1202 , the system identifies a relative position and alignment of the tractor unit to the trailer. This includes using at least one sensor of the tractor unit to detect information about the trailer so that the system can determine the relative position and alignment. In response to the position and alignment information, wheels of the tractor unit are adjusted in order to align the tractor unit with the trailer, as shown in block  1204 . Then, in block  1206 , upon adjusting the wheels, the tractor unit is backed up toward the trailer. The system may continue to receive information from the sensor(s) and use that information to adjust wheel alignment as the tractor unit backs up. Once the tractor unit is close enough, a coupling mechanism of the fifth-wheel is engage with the kingpin of the trailer, as indicated in block  1208 . The system then establishes a pneumatic connection (block  1210 ) and an electrical connection (block  1212 ) between the fifth-wheel and the kingpin in the manner described above. At this point, a control system or other subsystem of the vehicle may check the status of the trailer or its cargo, and prepare for driving in an autonomous or non-autonomous mode. 
       FIG.  13    provides an example method  1300  of decoupling the tractor unit from the trailer. Per block  1302 , the landing gear of the trailer are deployed to contact a ground surface. This will provide a stable base once the tractor unit is disengaged from the trailer. The pneumatic connection (block  1304 ) and the electrical connection (block  1306 ) between the fifth-wheel and the kingpin are disengaged. At block  1308 , the coupling mechanism is decoupled from the kingpin. And at block  1310 , the tractor unit can be driven away from the trailer. 
     Unless otherwise stated, the foregoing alternative examples are not mutually exclusive, but may be implemented in various combinations to achieve unique advantages. As these and other variations and combinations of the features discussed above can be utilized without departing from the subject matter defined by the claims, the foregoing description of the embodiments should be taken by way of illustration rather than by way of limitation of the subject matter defined by the claims. In addition, the provision of the examples described herein, as well as clauses phrased as “such as,” “including” and the like, should not be interpreted as limiting the subject matter of the claims to the specific examples; rather, the examples are intended to illustrate only one of many possible embodiments. Further, the same reference numbers in different drawings can identify the same or similar elements. The processes or other operations may be performed in a different order or simultaneously, unless expressly indicated otherwise herein.