Method for remotely determining and managing connection of tractor and trailer

Truck tractors in a transportation fleet include a transponder that transmits a unique tractor identifier to a connected trailer using a Power Line Communication (PLC) bus device. The information transmitted typically includes a manufacturing unique ID for the tractor and an optional user defined ID. The user defined ID may include a fleet division code. The tractor ID and/or fleet ID codes determine how the trailer is hooked up. In particular, with detection of a connected state signal from the PLC bus, together with receipt of tractor identification code(s) from the tractor, the trailer tracking device can now communicate the coupling event information to a centralized location, such as via a cellular telephone connection.

BACKGROUND OF THE INVENTION

The present invention relates to data communications between a truck tractor and a cargo trailer, and more specifically to techniques for remotely determining and managing their connection.

Mobile asset management is a major concern in various transportation industries such as trucking, railroad and rental cars. In the trucking industry, an asset manager needs to keep track of the status and location of each tractor and cargo trailer in a fleet. The fleet asset manager should also know whether each trailer is in service (i.e., already in use being transported by a tractor) or out of service (i.e., not being transported by a tractor at the present time). The asset manager should have similar information with respect to whether each tractor in a fleet is hauling a trailer or not, and thus whether it is available for service. The fleet asset manager should also be able to monitor the progress of each tractor and trailer according to a predefined plan, for scheduling purposes.

One difficult aspect of asset management concerns the availability and status of cargo trailers. Although empty trailers are often numerous and widely available, they are nomadic, can be scattered across a wide territory, and it is often difficult to know their specific status with certainty. Automated trailer tracking systems, such as described in U.S. Pat. No. 6,529,529 assigned to Terion, Inc., the assignee of the present invention, greatly enhance capabilities for fleet management. These systems typically include various sensors and communication units located on the tractor and trailer. The sensors can be used to determine the status and location of a trailer, check for proper operating conditions, determine any misuse, and monitor the progress of each tractor and its associated coupled trailer for scheduling and security purposes.

Automated tracking systems have become quite popular, as they allow transportation carriers and shippers to better manage their assets. However, one aspect that is not well tracked is the connection of a trailer to a specific tractor or type of tractor.

In the typical scenario, it is the sole responsibility of the driver to identify and communicate tractor/trailer connect and disconnect events to fleet managers via the asset management system. Unfortunately, the human driver can make mistakes, in occasionally picking up the wrong trailer, or in communicating the trailer identification number incorrectly. Such methods also do not address scenarios when someone intent on compromising a trailer or its cargo simply commits an outright theft of a trailer.

In certain other electronic systems used on trucks, status information for a trailer may be communicated to a tractor. See for example, U.S. Pat. No. 6,799,814 which describes a system wherein an Anti-lock Braking System (ABS) produces a data signal. The ABS data signal is then sent to the tractor using a Power Line Carrier (PLC) type communication bus. In this manner, the status of a subsystem such as the status of the braking system may be displayed or may otherwise made available to the driver.

SUMMARY OF THE INVENTION

The present invention is a method for remotely determining and managing the connection of a tractor to a trailer. The invention uses a trailer tracking device which can determine the location of a trailer, such as via a Global Positioning System (GPS) receiver, and other status information. The trailer tracking device also has a wireless communication subsystem, such as a cellular radio telephone modem, which permits data to be exchanged between the trailer and a trailer asset management system located at a central location.

The trailer tracking device also includes a Power Line Carrier (PLC) communication device. The PLC device may, for example, use the seven-pin industry standard J560 cable as a bus, and communication protocols associated with the so-called PLC4TRUCKS protocol developed as the Society of Automotive Engineers (SAE) J1587 standard, to transmit data on the bus.

Each tractor in a transportation fleet of interest includes a transponder that transmits a unique tractor identifier to any connected trailer using the PLC device. The tractor ID transponder can transmit on a periodic schedule and/or upon receiving a query message from the trailer tracking device to which it is coupled. The information transmitted will typically include a manufacturing unique ID for the tractor as well as an optional user defined ID. The user defined ID may include a fleet division code, for example, which can identify the fleet, or a subset of a fleet, to which the particular tractor belongs.

Upon connection of a trailer equipped with a trailer tracking device to any tractor equipped with the transponder, the trailer tracking device will receive the associated tractor ID and/or fleet ID codes from the tractor. These codes, which uniquely identifier the tractor that now has possession of the trailer, can then be used to determine how the trailer is now hooked up. In particular, with detection of a connected state signal from the PLC bus, together with receipt of tractor identification code(s) from the tractor, the trailer tracking device can now communicate the coupling event together with the tractor ID and trailer ID information to the trailer management system located at a centralized location.

The occurrence of this sequence events provides three levels of information to the trailer management system:the presence of communication from the tractor ID transponder indicates that the trailer is hooked to a tractor and is currently in use;the tractor ID can be used to uniquely identify the tractor that is coupled to the reporting trailer;when cargo loads are assigned to specific drivers and specific trailers, the trailer management system can then also determine if a correct pairing of tractor and trailer has occurred; andif a tractor is coupled to an incorrect trailer, an intervening action can occur before the trailer is moved.

In accordance with other aspects of the invention, an additional level of tractor/trailer management can be provided with the use of fleet codes. As explained above, fleet codes can be assigned to a subset of tractors. In one scenario, the trailer tracking device can then store one or more fleet codes that are authorized for assignment to that particular trailer. If the tractor that couples to a trailer reports a fleet code that is not authorized for assignment to that particular trailer, then the trailer tracking device can determine that an incorrect pairing has occurred, and communicate that fact to the centralized location. Again, an intervening action can be taken by the trailer management system.

In an alternative approach, the system can determine the incorrect pairing at the centralized location. This can be done by maintaining a list of allowable fleet codes at the centralized location, and by simply having the trailer tracking device report the fleet codes of both the tractor and trailer. The second approach makes management of tractor and trailer pairings to fleet codes easier, but requires that each coupling of a tractor to a trailer be reported to the centralized location.

In accordance with still further aspects of the invention, another level of fleet management can be provided if the fleet of trailers is configured to only permit assignment to identifiable tractors. In this configuration, if a coupling occurs and the tractor can not provide an identification to the trailer tracking device, an incorrect pairing can be reported to have occurred. The trailing tracking device can report this event as the trailer having been picked up by unauthorized tractor.

The trailer tracking device can also periodically query the tractor ID transponder for its identification code(s). Continued receipt of these codes by the trailer tracking device is evidence that coupling status has not changed, and that the trailer remains hooked to the previously identified tractor.

If, in this mode, a trailer tracking device does not receive a response after multiple successive queries to the tractor ID transponder apparatus, it can be determined that a connection between the tractor and trailer no longer exists, and the trailer has become unhooked. This information can then be communicated by the trailer tracking device to the centralized location as for example, an unhooked trailer event.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a high level diagram of the components of a system10that can be used to manage the connection between a truck tractor100and an associated cargo trailer110. Briefly, the tractor100contains a small transponder device that communicates tractor identification (ID) data to a trailer tracking and communication device installed in the trailer110. The trailer110in turn communicates this and other data over a wireless link130(such as may be provided by a cellular telephone network) to a Trailer Management System (TMS)150. The system10permits the trailer tracking device112to report certain events to a central location such as when a trailer is hooked or unhooked from a tractor100, which tractor100picked it up, and other notification such as when an unauthorized tractor hooks to a trailer.

More particularly, the tractor100has installed in it a transponder called a Tractor Identification Unit (TIU)102. The TIU102stores and provides (either periodically or upon request) one or more data values indicative of identification information for the specific tractor100. The identification information may include a tractor ID, a fleet ID, and other information. While the TIU102is shown as a stand alone electronic device (in this case a small transponder) it should be understood that the TIU102may also form part of a larger electronic system in the truck100such as a data processing system.

In the preferred embodiment, the TIU102provides identification information to a Trailer Tracking Device (TTD)112installed in trailer110via a connection120. The connection120may be provided in a number of different ways. In a preferred embodiment the connection120is provided by a physical connection such as the Society of Automotive Engineers (SAE) standard J560 seven conductor cable. These cables are now used to couple the Anti-lock Braking System (ABS) of a tractor to a trailer according to the United States National Highway and Traffic Safety Administration (NHTSA). In the preferred embodiment, tractor ID information is carried over the J560 cable120using a Power Line Communication (PLC) interface. A PLC interface104is associated with a tractor100, and a similar PLC interface114is associated with a trailer110. The PLC interface uses known power line carrier based communication protocols, such as the PLC4TRUCKS protocol (based on the SAEJ1587 standard). These protocols specify media access control (MAC) layer formatting for messages. The TTD112is thus capable of receiving and transmitting messages from and to the tractor110over a PLC bus provided by the cable120.

Also in a preferred embodiment, the PLC interfaces104,114may make use of standard integrated circuits such as the P111PL Media Interface Integrated Circuit (IC) and SSCP485PL Transceiver IC as available from Intellon Corporation of Ocala, Fla. These transceivers use spread spectrum based communication techniques to enable data transmission over the J560 cable120.

The TTD112also provides a trailer tracking device function. Thus, it typically includes a Global Positioning System (GPS) receiver capable of determining a location by triangulation of signals received from a satellite, as in accordance with techniques that are well known. In addition, the TTD112may receive inputs from sensors associated with the trailer110such as a wheel sensor, temperature, humidity, pressure, door open/close other sensors.

One of the primary purposes of the TTD112has thus been to periodic report a position for the trailer110to the TMS150. This permits the user of the TMS150to track not only the single trailer110, but also a fleet of trailers from a central location. This in turn allows for more effective management of a fleet of such trailers110, assigning empty trailers as needed and as they become available, and the like.

The TTD112contains also a small data processing unit such as a microprocessor enabling it to carry out simple data processing tasks. Among those tasks are detection of tractor ID messages from the TIU102, providing status reports such as location and other status information to the TMS150over the wireless link130. In addition to forwarding tractor ID and paired trailer ID information to the TMS150, the TTS has stored therein identification information associated with the particular trailer110in which it is installed. Thus, for example, the TTD has available to it data fields corresponding to a trailer ID.

In addition, the TTD112may communicate messages to a central location at which the TMS150is installed, via wireless link130. Wireless link130may be provided by the standard cellular telephone infrastructure. In this case, the TTD112connects via a cellular telephone antenna116and base station antenna130to a wireless Network SubSystem (NSS)134, which in turn acts as an interface for receiving and transmitting messages to and from the TTD112. The NSS is in turn connected to the TMS150such as via suitable telecommunication network151.

The TMS150is a data processing system that enables the user to maintain and manage information regarding trailers110and tractors100. The TMS150typically consists of a user interface device such as a personal computer152that may be connected to the TMS150via a network connection153. The TMS150may include database server158which may be a networked server that is also connected via another network connection157.

It should be understood that modifications can be made to the various data processing systems shown inFIG. 1. For example, while the network connections151,153, and157may be connections made through telecommunications network such as the Internet and/or virtual private networks or other telephony networks that other connections can be made either directly or through Local Area Network, Wide Area Networks, or the like. Similarly, the wireless link130may be provided by other types of wireless networks such as satellite networks, paging networks, cellular packet data networks, or other wireless networks that provide relatively wide area coverage.

The tractor ID information is transferred using a certain message200as defined by the PLC4TRUCKS protocol.FIG. 2Ais a diagram of a format of one such tractor ID message200that originates from the TIU102. The tractor ID message200contains a number of fields including a message ID (MID) field202, a parameter ID (PID) field204, and a tractor ID field206. The MID202is coded to identify the type and/or sender of the message200.

The PID field204is encoded with a special value that indicates that the message contains a tractor ID. In a preferred embodiment, one of the available PLC4TRUCKS MIDs in the range of the so called unassigned MIDs (MID numbers112-127) could be assigned. There are also a number of PIDs that can be used to indicate a tractor ID message. Available PIDs include PID243, indicating a free form text message, is one such value.

In accordance with an alternate embodiment a second type of message210may originate from the TIU102. The second message210has a format similar to that of the first message200as it has a MID212, PID214, and tractor ID field216. However, this message210also includes a fleet ID218. As will be understood shortly the fleet ID field218provides an additional level of tractor/trailer management. For example, a fleet ID218can be assigned to a subset of tractors that are collectively represented by the particular fleet ID218.

The TIU102may periodically transmit messages200or210or may also provide this information upon receipt of a request message from the TTD112.

FIG. 3is a format of a message that may travel over the wireless link130from the TTD112to the TMS150. Such a message300may include a message ID field302indicating the type of message. Other fields associated with this message also include a tractor ID304identifying the tractor associated with a message, a trailer ID306field and an optional fleet ID field308. This message is then processed by the TMS150to determine if an appropriate pairing of tractor and trailer have occurred.

Turning attention toFIG. 4, there is shown a sequence of steps that can be carried out by the TTD112to make such a determination. In a first step402(which is an optional step), a tractor/trailer connect event can be detected. Such an event may be provided by an indication received from the PLC interface114, a physical connection of the PLC114in the trailer is made to a corresponding PLC104in the tractor100. Such an indication may be given, for example, upon detection that current is flowing on the PLC bus120.

In a next step404a tractor ID message200or210is received.

In step406, the TTD next combines the received tractor ID information and its own trailer ID information to create a message300as shown inFIG. 3. The message300is then communicated to the TMS150at the central location.

The occurrence of this sequence of events (including at least steps404and406inFIG. 4) provides three pieces of information to the TMS150. In particular, the TMS150is now aware that:

(1) the trailer110is hooked to a tractor100and is currently in use;

(2) an identifier associated with the tractor (i.e., tractor ID field206) now uniquely identifies the tractor that is coupled to the uniquely identified trailer (i.e., trailer ID field306); and

(3) if a correct pairing of tractor and trailer has occurred, such as by performing a database158lookup of cargo loads assigned to specific drivers and specific trailers.

It should also be understood that the type of message shown inFIG. 2Bwhich includes a fleet ID may also be communicated by the steps404and406. This can permit an additional level of tractor/trailer management. Thus for example, the TTD112can be configured by the user to contain a list of fleet codes that are authorized for assignment to a particular trailer. Incorrect pairing of mismatched fleet codes can be then detected at the centralized location via a database158lookup.

If a tractor has coupled to an incorrect trailer, an intervening action can be taken before the trailer is moved. For example, the unauthorized connection can be reported to the driver or the manager of a yard in which the trailer110is located. In more sophisticated systems, it may be possible via remote control commands received via the TTD112to lock the wheels of the trailer110, preventing its movement until further authorization has been obtained.

Yet another level of tractor/trailer management can be provided if the fleet of trailers is configured to only permit assignment to identifiable tractors. For example, in the sequence of events shown inFIG. 5, the TTD112receives at some point in time one or more authorized fleet codes. The fleet codes indicate the group of trailers110to which the particular belongs. These may be all of the trailers owned by a particular service provider or a subset thereof. At a later time, such as at state504, a tractor ID message is then received including both tractor ID and fleet code fields. In state506, the fleet code received in a message is matched against the previously received authorized fleet codes. If the fleet codes do not match, then in state508the tractor ID and trailer ID field mismatch is reported as an event to the TMS150. This is provided by sending an appropriate message in a predetermined format over the wireless link130. At a next step510(which occurs at the TMS150, after receiving such a message) the TMS150takes remedial action such as preventing further use of the trailer via locking its wheels or doors until further authorization is obtained.

If, however, in state512the TDD112determined that there was a fleet code match, then the fleet code match event is reported to the TMS150. In this sequences of events, at state514, the TMS150notes the correct pairing of tractor and trailer in the database158, and then continues with normal status monitoring.

FIG. 6shows another sequence of events that may occur at the TTD112. Here, in state602, a tractor/trailer connect event is detected, similar to the previously described state402. However, in state604a time out event occurs. In particular, a predetermined time expires during which no tractor ID message in the form of message200or210is received. At this point, in state606, a possible unauthorized pickup is reported. This can be associated with detecting trailer movement so that idle trailers are not reported inappropriately. Thus, for example, if there is a tractor/trailer connect event and then time out in state604, followed by detected movement of the trailer, (such as determined by GPS data) then a possible unauthorized pickup event606can be reported to the TMS150.

Also in connection withFIG. 6, if a coupling between tractor and trailer occurs and the tractor cannot provide an identification to the satisfaction of the trailer tracking device, then an incorrect pairing can be determined to have occurred. The trailer tracking device112then reports the trailer to have been picked up by an unauthorized tractor or perhaps even having been stolen at this point.

FIG. 7is another sequence of events that may occur using time outs. This sequence of events determines whether a tractor/trailer is still connected. In particular, in a state702(which may follow at some time after state406ofFIG. 4or state512ofFIG. 5) a later report message200,210is received indicating the same tractor ID and/or fleet ID as was previously seen. If this message is received in state704, then a report can be made that the same tractor ID and trailer ID are still connected. If, however, later reports of coupled tractor ID and fleet ID are not received after a particular time out period, a state706is entered in which an unhook event for the particular tractor ID and trailer ID can be reported.

Further in connection withFIG. 7, the periodic querying of the tractor ID transponder102for its identification codes followed by continued proper receipt of these codes by the TTD112is evidence that the coupling status has not changed and that the trailer110remains coupled to an authorized tractor100. If however, as shown inFIG. 7, the TTD112does not receive a response after multiple successive queries to the TIU102it can be determined that the connection between the tractor/trailer no longer exists and that the trail110has been unhooked.