Patent Application
20100049384
This invention relates generally to the field of locomotive control, and more particularly to controlling an operation of a remote locomotive in a distributed power train having a communication system for transmission of communication signals between a lead locomotive and a remote locomotive.
Distributed power train operation supplies motive power from a lead locomotive and one or more remote locomotives spaced apart from the lead locomotive in a train consist. Each lead and remote locomotive includes an air brake control system for controlling braking operations and a communication system for exchanging information between lead and remote locomotives over a communication link. Distributed power train operation may be preferable for long train consists to improve train handling and performance, especially for trains operating over mountainous terrain.
A distributed power train control and communications system generates traction and braking commands responsive to operator-initiated control of a traction (or throttle) controller (e.g., throttle handle) or a braking controller (e.g., brake handle) in the lead unit. The commands are transmitted to the remote locomotives over a radio frequency communications system (such as the LOCOTROL® distributed power train communications system available from the General Electric Company of Schenectady, N.Y.) including transmitter and receiver components at the lead and the remote units for communicating over a radio frequency link (channel).
For example, when the lead unit operator operates the lead-unit throttle controller to apply tractive effort from the lead unit, the distributed power control and communications system commands each remote unit to supply the same tractive effort. Upon execution of the received command, each remote unit responds to the lead unit with a reply message indicating implementation of the tractive effort command. The distributed power control and communications system can be configured to various operational modes that affect interaction between the lead and remote units and the implementation of lead unit commands at the remote unit.
The lead unit also sends other message types to the remote units, such as status request messages, to which the remote units respond by sending a status reply message back to the lead unit. The status reply message indicates the current operational status of the replying remote unit. Messages from the lead locomotive to the remove units and vise versa are typically sent at predetermined time intervals, for example every twenty seconds. If the communications system is inoperative or the communications link between the lead unit and one or more remote units is disrupted (for example, if line-of-sight directivity is lost due to track topology or an interfering object), lead-initiated braking and traction commands are not received by the remote unit(s). In particular, if the lead operator commands an increase in tractive effort because the train is climbing a hill, the remote units will not receive the tractive effort command.
Currently, when a remote unit determines there is a communication loss, the remote unit initiates an algorithm to progressively lower the tractive effort to a presumably safe speed. However, reducing the tractive effort at the remote in such a scenario may increase the load requirements of the lead unit slowing the train as it attempts to climb the hill. In addition, the train speed is reduced, which may have an effect on whether the train is able to meet a trip schedule. In a worst case scenario, the reduction in tractive effort at the remote may generate sufficient in-train forces that can break the train and/or cause a train derailment.
A distributed power train comprises a lead locomotive unit, a remote locomotive unit, a plurality of railcars, and a communications system that transmits information signals between the lead unit and remote unit. The lead unit is controlled by operation of lead unit controls, and the remote unit is controlled by commands issued from the lead unit to the remote unit over the communication system. An embodiment of the invention relates to a system for operating the distributed power train, and comprises a controller at the remote unit for issuing commands to control the operation of the remote unit on a track and responsive to a communication loss between the lead unit and the remote unit. A memory, accessible by the controller, comprises data relative to a track profile including a plurality of geographical coordinates of the track and data relative to one or more throttle positions or braking operations for the remote unit that are associated with the geographical coordinates. The controller receives data relative to geographical coordinates of the remote unit and upon a detection of the communication loss between the remote unit and lead unit, the controller compares the geographical coordinates of the remote unit to the track profile geographical coordinates and issues one more throttle position or braking operation commands associated with the remote unit and track profile geographical coordinate data to control the movement of the remote unit on the track during the communication loss.
In another embodiment, a method for operating a distributed power train comprises storing in a memory, at the remote unit, track profile data comprising a plurality of geographical coordinates of a track on which the remote unit travels and data relative to one or more throttle positions or braking operations for the remote unit associated with the track profile geographical coordinates. In addition, the method comprises storing in a memory, at the remote unit, data relative to geographical coordinates of the remote unit as the remote unit is moving on the track; determining at the remote unit that there exists a communications loss between the lead unit and the remote unit while moving on the track; and identifying, at the remote unit, the track profile geographic coordinate data and the associated throttle position or braking operation data that are associated with the geographic coordinates of the remote unit. Responsive to identifying the associated throttle position or braking operation data, the method further comprises issuing, at the remote unit, one or more commands to control movement of the remote unit during the communication loss.
Additional embodiments of the invention are applicable to other distributed power vehicle systems that travel along a designated route (that is, a series of linked vehicles having a lead powered vehicle and a remote powered vehicle), such as mine vehicles and marine vessels (e.g., a series of linked tugboats). Also, the terms “lead” and “remote” as used herein are to designate different powered vehicles (e.g., locomotives) in a distributed power vehicle system (e.g., train), and do not necessarily represent the physical position of the vehicle within the system. For example, it may be the case that the lead locomotive in a distributed power train is located at the end of the train (for a pushing operation) or somewhere in the middle of the train.
The present invention can be more easily understood and the further advantages and uses thereof more readily apparent, when considered in view of the following detailed description when read in conjunction with the following figures, wherein:
In accordance with common practice, the various described features are not drawn to scale, but are drawn to emphasize specific features relevant to the embodiments of the invention. Reference characters denote like elements throughout the figures and text.
A more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained. Before describing in detail the particular method and apparatus for controlling of movement of a train in accordance with the present invention, it should be observed that the present invention resides primarily in a novel combination of hardware and software elements related to said method and apparatus. Accordingly, the hardware and software elements have been represented by conventional elements in the drawings, showing only those specific details that are pertinent to the present invention, so as not to obscure the disclosure with structural details that will be readily apparent to those skilled in the art having the benefit of the description herein.
Throughout the description of the embodiments of the invention, the terms “radio link,” “RF (radio frequency) link,” and “RF communications” and similar terms describe a method of communicating between two links in a network, such as a lead and a remote locomotive of a distributed power train. It should be understood that the communications link between nodes (e.g., locomotives) in the system is not limited to radio or RF systems or the like and is meant to cover all techniques by which messages may be delivered from one node to another or to plural others, including without limitation, magnetic systems, acoustic systems and optical systems. Likewise, the invention is not limited to a described embodiment in which RF links are used between nodes and in which the various components are compatible with such links. In addition, the term “geographic coordinates” as used herein is intended to include the use of any means of indication of a location of an article, which may include the longitudinal and/or latitudinal readings, or elevation readings; the term is also intended to encompass identifying the location of a remote unit or other article in terms of the distance the remote unit is from one or fixed reference points such as a start location of destination of a trip plan, or the distance the remote unit is spaced from a wayside traffic control device such as a mile marker or a switch.
The lead unit 14 includes a lead controller 30 and a radio frequency module 28 for generating and issuing commands and messages from the lead unit 14 to the remote unit 12, and for receiving reply messages there from. Commands are generated at the lead controller 30 in response to operator control of the traction controller (throttle) and in response to operator control of the lead braking controller within the lead unit 14.
The remote unit 12 includes a remote controller 32 and remote communications module 28, for processing and responding to transmissions from the lead unit 14 transmitted over the communications link (e.g., by applying tractive effort or brakes at the receiving remote unit) and for issuing reply messages (e.g., acknowledging receipt and implementation of a lead unit command) and status messages back to the lead unit 14. (The term “controller” encompasses both single or stand-alone controllers, e.g., a microcontroller or computer, and systems of interoperable controllers.)
For example, when the lead unit operator operates a lead-unit throttle handle to apply tractive effort from the lead unit 14, the distributed power control and communications system commands the remote unit 12 to supply the same tractive effort. Upon execution of the received command, the remote unit 12 responds to the lead unit 14 with a status command indicating implementation of the tractive effort command. The distributed power control system can be configured to various operational modes that control interaction between the lead and remote unit and implementation of lead unit commands at the remote unit.
In one embodiment, the communications channel of the communications system includes a single half-duplex communications channel having a 3 kHz bandwidth. The messages and commands include a serial binary data stream modulating one of four available carrier frequencies using frequency shift keying modulation. The various bit patterns convey information including the type of transmission (e.g., message, command, alarm); the substantive message, command or alarm; the address of the receiving unit; the address of the sending unit; conventional start and stop bits and/or error detection/correction bits. The messages allow control of the remote unit 12 from the lead unit 14 and provide remote unit operating information back to the lead unit 14. The details of the system messages and commands and the transmission format of individual messages and commands are described in detail in commonly-owned U.S. Pat. No. 4,582,280.
Each message and command sent from the lead unit 14 is broadcast to the remote unit 12 and includes a lead unit identifier for use by the remote unit 12 to determine whether the sending lead unit is the lead unit of the same train. An affirmative determination causes the remote unit 12 to execute the received command. Messages and alarms sent from the remote unit 12 also include the sending unit's address. The receiving unit, i.e., the lead locomotive or another remote locomotive, can determine whether it is an intended recipient of the received transmission by checking the sending unit's identification in the message, and can then respond accordingly.
Each locomotive 14 and 12 further includes a dynamic brake controller 38. Application of the dynamic brakes in the lead locomotive 14 generates a signal communicated to the remote unit 12 over the communications link. Responsive thereto, the remote controller 32 controls the dynamic brake controller 38 of the remote unit 12 to activate dynamic braking. Generally, application of the dynamic brakes generates relatively uniform braking forces throughout the length of the train.
As the distributed power train 10 passes through certain terrain topographies or track segments with proximate natural or man-made obstructions, a line-of-sight communications link between the sending and one or more of the receiving units may be interrupted. Thus, commands from the lead unit 14 to the remote unit 12 and status messages from the remote unit 12 to the lead unit 14 may not be reliably received. Although high-power, robust transceivers may be capable of successfully transmitting the signal to the receiving unit under certain operating conditions, such equipment can be relatively expensive. Further, in some operating scenarios even a high-power transceiver cannot successfully effect communications, such as when a long train travels a curved track segment adjacent a natural obstruction such as a mountain, where the communications path between the lead unit and one or more remote units is obstructed by the mountain. In addition, as the train 10 passes through a tunnel certain transceivers may be unable to communicate with other transceivers aboard the locomotives. Thus, operation of the distributed power communications system may be interrupted for short periods during train operation.
A communications system for a distributed power train typically transmits signals at a predetermined time interval (for example every twenty seconds) to verify that a communication link between the lead unit and remote unit is active. If a signal or transmission has not been received at the remote unit from the lead for a second predetermined time (for example, one minute), the controller on the remote unit issues one or more commands to control operation of the remote unit. For example, if the remote unit is applying a tractive effort at the time of a communications loss, the controller on the remote unit will command the remote unit to change the throttle position to reduce the tractive effort. If there is a communication loss during a braking application, the remote unit maintains the last received dynamic brake command.
In an embodiment of the present invention, the controller 32 on the remote unit 12 is programmed or otherwise comprises algorithms to predict the throttle setting that the remote unit 12 should be traveling given the current track conditions and the location of the remote unit 12 on the track 16. The remote unit 12 is equipped with a GPS transceiver 34 that transmits data relative to the geographic coordinates of the remote unit 12 to the controller 32. In addition, the controller 32 has data stored as a database 24 in memory relative to a track profile for the track 16 on which the remote unit 12 is traveling. The track profile data 80, shown in
With respect to
The throttle positions for the geographical coordinates or ranges of geographical coordinates are dependant on the track grade and the direction in which the remote unit 12 is moving on the track 16. Accordingly, the database 24 may have data relative to a track grade associated with each geographical coordinate or with each range of geographical coordinates, and, for each track grade or range of track grades there may be at least one associated notch setting. The throttle position data may comprise more than a single throttle position associated with the geographical coordinates or range of coordinates. For example, when the remote unit 12 is traveling in one direction, e.g., uphill, the track grade may be significantly different than the grade when the remote unit 12 is traveling in the opposite direction on the track 16, e.g., downhill. Accordingly, two or more throttle positions may be associated with a single geographical coordinate or range of coordinates. Therefore, the controller 32 may be configured to determine the direction in which the remote unit 12 is traveling in order to select the appropriate throttle position associated with the geographical coordinates or range of coordinates of the track 16, track grade, or direction of movement of the remote unit 12.
Other data such as data relative to speed restrictions on the track and the distance the lead unit 14 is spaced from the remote unit 12 may be factored in determining the notch settings. In addition, the data relative to the throttle positions may be tailored for individual locomotives so that throttle positions may be associated with a particular remote unit. The data may also be grouped according to classes of vehicles. For example, remote units that may be classified according to similar characteristics such as engine size (e.g., 2000 hp, 4400 hp and 6000 hp) and/or locomotive weight; and, for each class of like units there may be associated throttle positions.
The controller 32 or the database 24 for the remote unit 12 may be configured to provide the track profile data including the throttle positions or track grade data in the form of a look up table. That is, once the controller 32 determines there is a communication loss and receives the geographical coordinates 52 of the remote unit 12 and data relative to the direction of movement of the remote unit 12 from the GPS transceiver 34, the controller 32 may be configured to access the database 24 to identify the next geographical coordinate 50 plotted for the track profile in the direction (represented by arrow 18) of movement of the remote unit 12, and identify the associated throttle position. With respect to
With respect to
In an embodiment of the invention the controller 32 on the remote unit 12 may have a database or memory that comprises data relative to a trip plan that includes the geographical coordinates of a start location of the lead locomotive and/or geographical coordinates of a destination location for the train. In addition, the memory or database includes the identity of one or more track segments in the trip plan and for each track segment there is a predetermined speed setting or planned speed for the lead unit 14 and remote unit.
With respect to
In operation and with respect to
By way of example and in reference to
While the above-described embodiments of the invention have been discussed in terms of throttle position, or changing throttle positions, the invention is also operable for issuing brake commands or changing between braking and tractive effort commands. In current distributed power trains, if the last communicated command from the lead unit to a remote unit is a brake command and there is a communication loss, the remote unit will continue to implement the brake command, which proves to be an inefficient operation if the train, including the remote unit, begins to travel uphill. In embodiments of the invention, the controller 32 is able to determine the appropriate command to increase power and change the throttle position or issue braking commands, because the controller 32 can determine a location of the remote unit 12 on the track 16 and determine the appropriate throttle position or braking dynamic associated with location of the remote unit 12 on the track 16.
As shown in
With respect to
As noted above, although embodiments of the invention have been described herein with respect to distributed power trains having lead and remote locomotive units, embodiments are also applicable to other distributed power vehicle systems that travel along a designated route (that is, a series of linked vehicles having a lead powered vehicle and a remote powered vehicle), such as mine vehicles and marine vessels (e.g., a series of linked tugboats).
Thus, one embodiment of the present invention relates to a method for operating a distributed power vehicle system having a lead powered vehicle unit and a remote powered vehicle unit, where the remote unit is controlled by commands transmitted from the lead unit to the remote unit over a communication system. In the method, the remote unit determines that there is a disruption in the communication system, preventing the transmission of commands from the lead unit to the remote unit. The remote unit identifies operational data that is associated with a vector of the remote unit along a designated route of the distributed power vehicle system. (“Vector” refers to one or more of position, speed, and direction of travel of the remote unit along the route.) The remote unit operational data is stored in a memory in association with a profile of the route (e.g., geographical data of the route), and is identified by comparing the vector of the remote unit to the profile of the route in the memory. (“Remote unit operational data” refers to data relating to the control or operation of the remote unit, such as data relating to control or operation of the propulsion system of the remote unit (e.g., throttle settings) and/or braking system of the remote unit, e.g., braking operation commands.) Based on the remote unit operational data identified in the memory, one or more commands are issued to control movement of the remote unit during the communication system disruption. For example, if the vector of the remote unit, in comparison to the geographical data or other profile data of the route in the memory, indicates that the remote unit is traveling quickly down a steep grade of the route when the communication system is disrupted, the remote unit operational data associated with the steep grade might indicate that a command be issued to activate the braking system of the remote unit.
As noted above, the terms “lead” and “remote” as used herein are to designate different powered vehicles (e.g., locomotives) in a distributed power vehicle system (e.g., train), and do not necessarily represent the physical position of the vehicle within the system. For example, it may be the case that the lead locomotive in a distributed power train is located at the end of the train (for pushing operations) or somewhere in the middle of the train.
In another embodiment, a computer readable memory medium for conducting a distributed power train operation comprises a computer module for storing in a memory, at the remote unit, track profile data comprising a plurality of geographical coordinates of a track on which the remote unit travels and data relative to one or more throttle positions or braking operations for the remote unit associated with the geographical coordinates. In addition, there is a computer module that stores in a memory, at the remote unit, data relative to geographical coordinates of the remote unit as the remote unit is moving on the track; a computer module determines at the remote unit that there exists a communications loss between the lead unit and the remote unit while moving on a track; and, a computer module identifies, at the remote unit, the track profile geographic coordinate data and the associated throttle position or braking operation data that are associated with the geographic coordinates of the remote unit. Responsive to identifying the associated throttle position or braking operation data, a computer module issues, at the remote unit, one or more commands to control movement of the remote unit during the communication loss.
The computer readable memory medium may also comprise a computer module that provides a transceiver on the remote unit for receiving geographical coordinate data for the remote unit from a global positioning system and transmitting the data to the controller. In addition, the media may comprise a computer module that provides data relative to a direction of movement of the remote unit on the track and the controller identifying a track profile geographical coordinate in the direction of movement of the remote unit and the associated throttle position or brake operation. The computer readable memory medium further comprises a computer module that provides data relative to the direction of movement of the remote unit on the track and a computer module that identifies a track profile geographical coordinate that is closest in proximity to the remote unit and the associated throttle position or brake operation.
The computer readable memory medium may also comprise a computer module that provides a track profile geographic coordinate data that includes a plurality of geographic coordinates of the track spaced apart and defines a plurality of track segments wherein each track segment is disposed between consecutive geographic coordinates. The data stored in memory comprises data relative to a throttle position or braking operation associated with each track segment. There is also provided data relative to a direction of movement of the remote unit and a computer module identifies a geographic coordinate of the track in the direction of movement of the remote unit, the track segment on which the remote unit is moving and the associated throttle position or braking operation.
The computer readable memory medium also data relative to the direction of movement of the remote unit on the and data relative to one or more throttle positions or brake operations associated with track profile geographical coordinate data in one direction of movement on the track, and data relative to one or more throttle positions or brake operations associated with track profile geographical coordinate data in an opposite direction of movement on the track. The throttle position and brake operation data for the remote unit moving in one direction is different than the throttle position or brake operation data for the remote unit moving in the opposite direction. In addition, or alternatively, the throttle position and brake operation data for the remote unit moving in one direction is the same as the throttle position and brake operation data for the remote unit moving in the opposite direction.
The module for storing data comprises a computer module for storing track grade data associated with one or more of the geographical coordinates of the track profile. In addition, or alternatively, the module for storing data comprises a computer module for storing data in the memory relative to a distance the lead unit is spaced from the remote unit. The module for storing data may comprise a computer module for storing data relative to one or more speed restrictions associated with the track profile. The distributed power train may comprise a fluid carrying brake pipe connecting the lead unit to the plurality of railcars and the remote unit and the remote unit having a brake control system in communication with the brake pipe The computer readable media further comprises a computer module that detects a brake pipe fluid pressure, a computer module that transmits one or more signals indicative of the brake pipe fluid pressure, and a computer module that issues a brake command to the remote unit and responsive to a change in the break pipe pressure indicative of a brake command issued by the lead unit.
While various embodiments of the present invention have been shown and described herein, it will be obvious that such embodiments are provided by way of example only and not of limitation. Numerous variations, changes and substitutions will occur to those skilled in the art without departing from the teaching of the present invention. Accordingly, it is intended that the invention be interpreted within the full spirit and scope of the appended claims.
Embodiments described above may be implemented on a suitable computer system, controller, memory, or generally a computer readable medium. For example, the steps of the methods described above may correspond to computer instructions, logic, software code, or other computer modules disposed on the computer readable medium, e.g., floppy disc, hard drive, ASIC, remote storage, optical disc, or the like. The computer-implemented methods and/or computer code may be programmed into an electronic control unit of an engine, a main control system of the locomotive, a remote control station that communicates with the locomotive unit, or the like, as described above.
