Current carrier tractor-trailer data link

We claim:

1. In a truck having a tractor with a mobile communications terminal and a trailer, said tractor capable of electrical connection to said trailer by a power and control bus which includes a power line for providing power from said tractor to said trailer, said truck having a trailer identification system for providing trailer identification information from said trailer, when connected to said power and control bus, to said tractor for transmission by said mobile communications terminal to a central facility, said trailer identification system comprising:

transmitter means located in said trailer for, when said trailer is coupled to said said tractor by said power and control bus, providing at predetermined times upon said power line of said truck power and control bus a unique identification signal representative of trailer identification information corresponding to said trailer and, wherein said transmitter means comprises:

processor means for, at predetermined instances in time and for a predetermined time period from each instance in time, generating a connect signal, and for during a portion of each time period, generating an identification code;

modulator means connected to said processor means for, during each time period, receiving said identification code, generating a carrier signal, modulating said carrier signal with said identification code, and providing an output of said identification code modulated carrier signal;

energy storage means connected to said processor means for, storing electrical power during each time period and providing stored electrical power to said processor means at times other than during each time period; and

coupling means connected to said power line, said energy storage means, said processor means and said modulator means for, during each time period, receiving said connect signal and in response thereto coupling electrical power from said power line to said energy storage means, said processor means and said modulator means, and coupling said identification code modulated carrier signal as said identification signal upon said power line, said coupling means further for, at times other than during each time period, electrically decoupling said energy storage means, said processor means and said modulator means from said power line; and

receiver means located in said tractor for, receiving and demodulating said identification signal as provided upon said power line, and providing each demodulated identification signal as said identification code to said mobile communications terminal.

2. The system of claim 1 wherein at least said trailer has a physical parameter monitoring system capable of measuring predetermined physical parameters, said physical parameter monitoring system responsive to an interrogation signal of providing data indicative of said measured physical parameters, and wherein said processor means is further for, during each time period, generating and providing said interrogation signal to said physical parameter monitoring system, said modulator means further for, during each time period, receiving said data from said physical parameter monitoring system, modulating said received data and providing said modulated data to said coupling means, said coupling means further for, during each time period, providing said modulated data as a data signal on said power line.

3. The system of claim 2 wherein said receiver means is further for receiving and demodulating said data signal as provided upon said power line, and providing said demodulated data signal as said data to said mobile communications terminal.

4. The system of claim 1 wherein said processor means is further for, during a current time period, computing a time interval between an end of said current time period and a beginning of a next time period.

5. The system of claim 1 wherein said trailer has an electrical system coupled to said power and control bus and wherein said system further comprises isolation means disposed in said power line between said transmitter means and said electrical system for isolating said identification signal, as coupled on said power line, from said electrical system.

6. The system of claim 1 wherein said modulator means comprises:

an oscillator having an output;

a frequency-shift key modulator having a carrier frequency input coupled to said oscillator output, a modulation input coupled to said processor means for receiving said identification signal, and an output; and

a low pass filter having an input coupled to said modulator output, and an output coupled to said coupling means.

7. The system of claim 1 further comprising power regulation means for, during each time period, receiving via said coupling means unregulated power from said power line, regulating said power line unregulated power, and providing said regulated power line power to said processor means, said modulator means and said energy storage means, said power regulation means further for, at times other than during each time period, receiving unregulated power from said energy storage means, regulating said energy storage means unregulated power, and providing said regulated energy storage means power to said processor means.

8. The system of claim 7 wherein said power regulation means comprises:

a first voltage regulator having a power input coupled to said coupling means and said energy storage means, and an output coupled to said modulator means;

a second voltage regulator having a power input coupled to said coupling means, a control input coupled to said processor means, and an output coupled to said modulator means; and

wherein said processor means if further for generating a disable signal at times other than during each time period, said second voltage regulator for receiving at said control input said disable signal and responsive thereto for disabling the providing of power to said modulator means.

9. The system of claim 1 wherein said coupling means, upon initial coupling of electrical power from said power line to said energy storage means, is responsive to a predetermined level of energy stored by said energy storage means for decoupling electrical power from said power line to said energy storage means, said processor means and said modulator means, said energy storage means for providing electrical power to said processor means prior to a first predetermined time period.

10. The system of claim 1 wherein said modulator means frequency-shift key modulates said carrier signal and wherein said receiver means further comprises:

demodulator means for, receiving and frequency-shift key demodulating said indentification signal, and providing said identification code; and

interface means for receiving from said demodulator means said identification code, buffering said identification code and providing an output of said identification code to said mobile communications terminal.

11. The system of claim 3 wherein said modulator means frequency-shift key modulates said carrier signal and wherein said receiver means further comprises:

demodulator means for, receiving and frequency-shift key demodulating said indentification signal and said data signal, and respectively providing said identification code said data; and

interface means for receiving from said demodulator means said identification code and said data, buffering said identification code and said data, and providing an output of said identification code and said data to said mobile communications terminal.

12. A tractor-trailer data link for communicating information between a tractor and at least one trailer upon a common power line coupling said tractor to each trailer with said tractor providing electrical power to each trailer upon said power line, said data link comprising:

transmitter means for locating in a corresponding trailer for, at predetermined times for a predetermined time period, electrically self-coupling to said power line, receiving electrical power from said power line, storing a portion of said received electrical power, generating a digital identification code indicative of trailer identification information, generating a carrier signal of a predetermined frequency, modulating said carrier signal with said identification code, and providing said identification code modulated carrier signal upon said power line connecting said tractor to said trailer, and for, during time intervals other than during each time period, electrically self-decoupling from said power line and using said stored portion of electrical power as transmitter means operational power; and

receiver means for locating in said tractor for, receiving said identification code modulated carrier signal transmitted upon said power line, detecting the modulation on said identification code modulator carrier signal with the detected modulation corresponding to said identification code, and providing an identification output signal corresponding to said detected modulation and indicative of said trailer identification information.

13. The tractor-trailer data link of claim 12 wherein an apparatus in a trailer is capable of providing trailer and/or load status information in the form of digital data, said transmitter means further for receiving digital data, modulating said carrier signal with said data, and providing said data modulated carrier signal upon said power line; and

said receiver means further for receiving said data modulated carrier signal transmitted upon said power line, detecting the modulation on said data modulated carrier signal with the detected modulation corresponding to said data, and providing a data output signal corresponding to the detected modulation and indicative of said trailer and/or load status information.

14. The tractor-trailer data link of claim 12 wherein said transmitter means frequency-shift key modulates said carrier signal with said identification code.

15. The tractor-trailer data link of claim 12 wherein said transmitter means frequency-shift key modulates said carrier signal respectively with said identification code and said data.

16. A method for providing trailer identification information to a tractor from a trailer when said tractor is coupled to said trailer comprising the steps of:

electrically coupling, at predetermined instances in time and for a predetermined time period from the occurrence of each instance in time, a transmitter to a power line connecting a tractor to a trailer;

receiving, in said transmitter during said time period, electrical energy from said power line;

storing in said transmitter a portion of said received electrical energy;

generating, in said transmitter during a portion of each time period, a digital identification code indicative of trailer identification indicia corresponding to said trailer;

generating, in said transmitter during each time period, a carrier signal of a predetermined frequency;

modulating, in said transmitter during each time period, said carrier signal with said identification code to produce an identification signal;

transmitting, from said transmitter upon said power line during each time period, said identification signal;

electrically decoupling said transmitter from said power line at times other than during each time period;

powering said transmitter with said stored electrical energy at said times other than during each time period;

receiving, upon said power line at a receiver in said tractor, said transmitted identification signal;

detecting the modulation on said received identification signal; and

providing an output signal corresponding to the detected modulation on said received identification signal wherein the detected modulation corresponds to said identification code.

17. The method of claim 16 for further communicating trailer and/or load status information to a tractor from a trailer comprising the steps of:

receiving, at said transmitter in said trailer, digital data indicative of trailer and/or load status information;

modulating, in said transmitter during a different portion of each time period, said carrier signal with said data so as to produce a data signal;

transmitting, from said transmitter upon said power line during said different portion of each time period, said data signal;

receiving, upon said power line at a receiver in said tractor, said transmitted data signal;

detecting the modulation on said received data signal; and

providing an additional output signal corresponding to the detected modulation on said received data signal wherein the detected modulation corresponds to said data.

Description Submit all comments and votes

BACKGROUND OF THE INVENTION

I. Technical Field

The present invention relates to mobile communication systems. More specifically, the present invention relates to a novel improvement in truck mobile communication systems which facilitates the transmission of trailer identification and trailer status information to a truck tractor which is capable of relating the information to a customer facility.

II. General Background

Mobile communication systems are utilized by commercial trucking companies to locate, identify and ascertain status of their vehicles. Mobile communications systems are also used to send information, and receive information and information requests from the operator of their vehicles.

A pressing problem facing todays trucking industry is the difficulty in keeping track of the location of its various trailers throughout the country. Quite often a trailer is left at a location, either by design or accident, and later forgotten about. The unnecessary down time on these commercial trailers can result in a substantial economic impact on the commercial trucking company.

It is standard practice for commercial trucking companies to offer bounties for the location of misplaced trailers unaccompanied by a tractor. This bounty motivates truck drivers and other drayage personnel to report the location of otherwise unreported mislocated trailers. The offering of a bounty also may motivate truck drivers to intentionally leave a trailer at an incorrect location so as to be able to claim that bounty when they report the location. This problem can result in an inordinate number of commercial trailers being left at inappropriate locations for an inappropriate amount of time.

Along with ascertaining the location of various trailers, it is also desirable to ascertain the status of equipment, environmental conditions, or payloads within these trailers. For example, it is useful to be able to monitor various parameters affecting the cargo of the trailers such as temperature and pressure inside the trailer. It is also useful to be alerted to potential hazards which may be indicated by parameters such as radiation levels and gas leakage.

A mobile communication system which implements a unit installed in the cargo carrying trailer can facilitate the communication of tractor-trailer connection and disconnection activity, as well as cargo status information, to a trucking company home base, via a mobile communications terminal within the tractor. It is desirable to have such a trailer unit utilize existing tractor-trailer electrical wiring and available power so as to minimize the modifications to the tractor and trailer needed to facilitate the implementation of this communication system.

It is therefore, an object of the present invention to provide a novel and improved mobile communication system which will facilitate locating and identifying misplaced commercial trailers.

It is another object of the present invention to provide a novel and improved method and apparatus for communicating trailer identification and status information to the driver of the tractor hauling the trailer, and to the trucking company home base via the mobile communications terminal in the tractor.

It is a further object of the present invention to provide a novel and improved method and apparatus for using existing tractor-trailer electrical wiring and available truck power to power the mobile communication system of the present with minimal power drain on the truck.

SUMMARY OF THE INVENTION

The present invention relates to a novel and improved trailer identification system which incorporates a tractor-trailer datalink which is capable of providing trailer identification information and status data to the tractor. A truck in accordance to the present invention is comprised of a tractor having a mobile communications terminal and at least one trailer. The tractor provides electrical power to each trailer by a common power bus. The trailer identification system provides trailer identification information to the tractor via the power bus to the truck for transmission by the mobile communications terminal. The trailer identification system comprises at least one transmitter located in a corresponding trailer for generating a unique identification signal representative of trailer identification information corresponding to the trailer in which the transmitter is located. The transmitter generates a carrier signal that is modulated by the identification signal. The transmitter then provides the identification signal modulated carrier signal on the power bus. A receiver located in the tractor receives each identification signal modulated carrier signal transmitted upon the power bus from a respective trailer and demodulates each signal to provide the identification signal. The identification signal is then provided as trailer identification information to the mobile communications terminal for transmission to a central facility.

The identification system may further comprise means by which the transmitter interrogates a physical parameter monitoring system in the trailer and in response thereto receives from the physical parameter monitoring system signals indicative of measured physical parameters. The transmitter modulates the parameter data and transmits the modulated data via the power bus to the receiver. The receiver receives and demodulates the modulated data signal and provides the demodulated data signal to the mobile communications terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, and advantages of the invention will become fully apparent from the detailed description set forth below when taken in conjunction with the drawings in which like reference characters correspond throughout and wherein:

FIG. 1 is an illustration of one environment of a mobile communication system in which the present invention may operate;

FIG. 2 is an illustration of an exemplary configuration of the present invention in which the major components are identified as installed in a trucking system;

FIG. 3 is a schematic diagram of the transmitter of the present invention;

FIG. 4 is a flowchart illustrating the operation of the transmitter of FIG. 3;

FIG. 5 is a diagram of the timing and coordination of the signals generated in the transmitter electronics; and

FIG. 6 is a schematic diagram of the receiver of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

One communication system environment in which the present invention may operate is depicted in FIG. 1. In FIG. 1 the communication system is illustrated as having a mobile terminal (not shown) mounted in a vehicle such as truck 10. Truck 10 is illustrated in FIG. 1 as comprising tractor 12 and trailers 14a and 14b. Although truck 10 is 15 illustrated as having two trailers, trailers 14a and 14b, it is understood that more or fewer trailers may be utilized. Truck 10 represents any of a variety of vehicles whose occupants desire to obtain occasional or updated information, status reports, or messages from a central communication source. A system such as this would allow truck drivers and personnel ready access to messages for more efficient operation.

It is also very desirable to have a mobile system user, such as truck 10, to be able to communicate at least some form of limited message or acknowledgment to a central control station. Such messages may be unsolicited messages provided from the truck or messages generated in response to received messages. A reply message may prevent the need for further communications, or indicate a need for additional information or updated messages from new information provided by the vehicle driver. At the same time, by providing for a return link of communication, even if limited in content, it is possible to incorporate other features into the communication link. Such a return link communications may be in the form of a simple message of acknowledgment to provide verification of a message received by the terminal, whether or not the driver operates on the information. Other automatic responses may also be configured into the operation of the transceiver such as vehicle location, vehicle status, trailer identification or trailer status. The return link can also allow a driver to enter messages such as verification of time and delivery information, or a report on current position or other status information.

In the operation of the communications system, a message is transmitted between truck 10 and central transmission facilities or terminal 16, also referred to as a hub, typically via satellite 18.

Hub 16 is typically located in a remote location ideally suited for low interference ground to satellite transmission or reception. One or more system user facilities, i.e. customer facility 20, in the form of central dispatch offices, message centers, or communication offices, are tied through telephonic, optical, satellite, or other dedicated communication link to hub 16 via network management center 21. Network management center 21 can be employed to more efficiently control the priority, access, accounting, and transfer characteristics of message data. Network management center 21 is typically located at the same location as hub 16.

Network management center 21 is interfaced to existing communication systems using well known interface equipment such as high speed modems or codecs to feed message signals into the communication system. Network management center 24 utilizes high speed data management computers to determine message priorities, authorization, length, type, accounting details, and otherwise control access to the communication system.

Operating in a communication system environment such as that depicted in FIG. 1, the present invention would allow the communication from the mobile terminal in truck 10 to customer facility 18 to include trailer identification and load status information. In such a system each trailer is assigned a unique trailer identification number or code. A transmitter (not shown) is typically located in each trailer for generating a corresponding identification code. The identification code is then transmitted to a receiver (not shown) located in tractor 12 via the existing power and indicator control cabling or wiring between trailers 14a and 14b, to tractor 12. The receiver provides the identification code to the tractor mobile communication terminal (not shown) for transmission to hub 16. Position of a trailer, once detached from the tractor, may be derived from the location of truck 10 at which the last transmission of the trailer identification information by the mobile communications terminal to hub 16 occurred.

Throughout the description herein, the invention is described with the transmitter being located in the trailer. However, it should be further understood that the transmitter may be used in association with any vehicle-type

existing power and indicator control cabling. An example of one such vehicle is the well known dolly.

Referring to FIG. 2, the elements of the data link of the present invention consists of one or more transmitters, transmitters 22a and 22b, each of which are respectively located in a trailer, trailers 14a and 14b. Although truck 10 is illustrated in FIG. 2 as having two trailers each with a transmitter, it is envisioned that only one trailer with a transmitter may be utilized. Furthermore, it should be understood that one or more trailers may be utilized with all or fewer than all having transmitters. Tractor 12, which hauls trailers 14a and 14b, has located therein receiver 24 which interfaces transmitters 22a and 22b to mobile communication terminal 26 also located in tractor 12.

It is a feature of the present invention to utilize the existing electrical wiring of the tractor and trailers for communication from transmitters 22a and 22b to receiver 24. Receiver 26 and transmitters 22a and 22b are also coupled to the existing wiring so as to allow access to the truck battery power, in addition to allowing communication between receiver 24 and transmitters 22a and 22b.

Tractor 12 includes an electrical system 28 which incorporates a battery, a battery recharging system and electrical controls including indicators and various other well known electrical apparatus. Electrical system 28 provides battery power to mobile communications terminal 26 and to receiver 24. Electrical system 28 also provides an output of battery power and trailer indicator control typically at a seven-pin connector 30. A seven conductor pig-tail cable 31 is used to couple battery power and trailer indicator control signals from tractor 12 to trailer 14a. Cable 31 includes a mating connector 32 at one end thereof for coupling cable 31 to connector 30. A second mating connector 33 is coupled at the other end of cable 31. Connector 33 mates with connector 34 at trailer 14a. Trailer 14a includes an electrical system 36a along with transmitter 22a that is connected to connector 34. Electrical system 36a typically includes trailer indicator lights such as stop lights, running lights, turn signals, brake lights, and etc.

When an additional trailer, such as trailer 14b, is connected to trailer 14a, it is also electrically coupled to tractor 12 via the wiring of trailer 14a and pig-tail cable 38. Trailer 14b also includes an electrical system 36b along with transmitter 22b that are coupled to cable 38. Electrical system 36b may be the same in terms of function as electrical system 36a or slightly different according to the type of trailer utilized.

Transmitters 22a and 22b may perform two basic functions. First, all transmitters generate an identification code or number unique to the trailer to which they are installed, which they can communicate to the receiver. Second, specially configured transmitters may provide the capability for acquiring information from various data monitoring systems which may be installed in the trailer, and communicate this information to the receiver.

FIG. 3 is a schematic diagram of an exemplary transmitter 22 of the present invention. Transmitter 22 as illustrated in FIG. 3 is an embodiment of each of transmitters 22a and 22b of FIG. 2. Portions of the +12 volt d.c. auxiliary conductor of the existing trailer wiring are indicated by the reference numerals 50 and 51. Conductor or line portion 50 connects the tractor/trailer connector to transmitter 22 and tuned circuit 52. Conductor or line portion 51 connects the trailer electrical system, and any other trailer electronics, to tuned circuit 52. The trailer electrical system and electronics other than that of the transmitter, such as indicator lamps, that are also coupled to the auxiliary conductor are isolated from high frequency signals generated by transmitter 22 by tuned circuit 52 and vice versa. Tuned circuit 52 is comprised of parallel coupled capacitor 54 and inductor 56.

Transmitter 22 is further coupled to line portion 50 at one end respectively of resistors 58, 60 and 62. The other end of resistor 58 is coupled to the drain of n-channel FET 64 and the gate of n-channel FET 66 while the sources of FETs 64 and 66 are coupled to ground. The other end of resistor 60 is coupled to the drain of FET 66, the drain of n-channel FET 68, and the gate of p-channel FET 70. The other end of resistor 62 is coupled to the drain of FET 70 and through surge protection circuitry, i.e. back-to-back zener diodes 72, to ground.

The gate of FET 68 is coupled to an output of microprocessor controller 74 by line 76 while the source of FET 68 is coupled to ground. The gate of FET 64 is coupled to one end of resistor 78 with the other end of resistor 78 coupled to ground. The gate of FET 64 is also coupled to the anode of zener diode 80. The cathode of zener diode 80 is coupled to one end of capacitor 82 with the other end of capacitor 82 coupled to ground. The source of FET 70 is coupled to one end of inductor 84. The other end of inductor 84 is coupled to the anode of diode 86. The cathode of diode 86 is coupled to one end of resistor 88, the one end of capacitor 82, and the cathode of zener diode 80. The other end of resistor 88 is coupled to the drain of n-channel FET 90, while the source of FET 90 is coupled to ground. The gate of FET 90 is coupled by line 92 to an output of controller 74 and to ground through resistor 94.

Controller 74 utilizes outputs for controlling the transmitter circuitry. One such output is coupled by line 76 to the gate of FET 68 as previously described. Another output is coupled by line 96 to a control input of power regulator 98. Another output is coupled by line 92 to the gate of FET 90 also as previously described. A pair of outputs are coupled by lines 100 and 102 to multiplexing logic 104. The final controller output is coupled by line 106 to interface logic 108.

Power regulator 110 receives input power on line 112 which is coupled to the nodal connection of the cathode of diode 86, the one end of resistor 88, the one end of capacitor 82 and the cathode of zener diode 80. Power regulator 110 provides regulated +5 volt d.c. power on line 114 to controller 74. Power regulator 110 is preferably a device having a low quiescent current and low drop-out voltage. Although a power regulator is preferred, it is envisioned that a series zener diode resistor combination may be utilized. A clock signal is provided to controller 74 from clock oscillator logic 116 which is comprised of capacitors 118 and 120, and crystal 122. Controller 74 also receives input digital data on input line 124, which is coupled from interface logic 108 from an external monitoring device as will be described later. Controller 74 is preferably a microprocessor controller which includes an internal memory for data and instruction storage. Controller 74 is also preferably of a type capable of a "sleep mode" in which minimal power is consumed and processing activity is suspended for a predetermined period of time. Multiplexer 104 also receives on line 102 from controller 24 an input select signal.

Interface logic 108 is comprised of an output portion and an input portion. The output portion couples a data request signal that is sent to a trailer data monitoring system for controller 74. The input portion couples data provided from the trailer data monitoring system to the transmitter. Interface logic 108 provides RS-232 level compatibility with external devices coupled to transmitter 22 at interface logic 108.

The output portion of interface logic 108 is comprised of inverter line driver 126 which has an i