Patent Application
20140081486
1. Technical Field
Embodiments of the invention relate generally to control systems for rail vehicles.
2. Discussion of Art
Rail car switching, shunting, and classification are integral aspects of rail freight operations. These procedures are performed in switching yards or classification yards, which include multiple rail tracks branching from one or more lead tracks and joining together at one or more exits. To maximize operational efficiency, several cars or trains of cars are typically moving simultaneously along different branches within a yard. Due to the presence of multiple stationary rail cars or stub trains on intervening tracks, an operator in a locomotive moving on a first track may not be able to see moving cars on a track branching from the first track. Accordingly, locomotive operators may coordinate their actions via a yardmaster stationed in a control tower overlooking the yard.
Three-way communication between operators and a yardmaster can potentially introduce lag time and error, which are undesirable while moving multiple pieces of heavy rail equipment. As such, some yards include systems by which a yardmaster may remotely control and coordinate movement of multiple stub trains (“tower control systems”).
In situations where the train may be on a grade (as may be found in connection with mining operations), there is a known tendency for “rollback” where the train moves opposite the applied tractive power. While rollback can often be quickly detected and corrected by an onboard operator, the phenomenon is more difficult to detect and slower to correct from a remote location such as would be occupied by a tower control system operator. Yet as discussed above, rail yard operations, generally, can be accomplished more efficiently by a tower control system operator than by an onboard crew. As will be appreciated, it is inefficient and undesirable to continuously crew a train in a rail yard, solely for the purpose of preventing rollback, particularly where the onboard crew might otherwise interfere with tower control system operation. As such, it is desirable to provide a tower control system that includes a specific and automated method to prevent rollback.
In embodiments, a system for controlling a rail vehicle includes an off-board control unit that is configured for communication with an on-board transceiver, which is mounted in the rail vehicle. The off-board control unit is further configured to receive a first signal indicative of a location of the rail vehicle and to, in response to the indicated location of the rail vehicle matching a pre-defined list of rollback locations, send to the on-board transceiver a second signal indicative of a tractive effort parameter corresponding to at least the indicated location of the rail vehicle.
In aspects, a method, e.g., a method for preventing rollback of a rail vehicle from a stopped condition, includes receiving a first signal indicative of the rail vehicle's location and, in response to the first signal, selecting from a lookup table one of a first plurality of pre-determined values of a braking parameter and selecting from the lookup table one of a second plurality of pre-determined values of a tractive effort parameter. The method then includes transmitting to the rail vehicle a second signal ordering movement of the rail vehicle from the stopped condition. The second signal includes the selected value of the braking parameter for controlling application of brakes of the rail vehicle and the selected value of the tractive effort parameter for establishing tractive effort of the rail vehicle.
In embodiments, a system for controlling a rail vehicle includes an on-board transceiver mounted in the rail vehicle and operatively connected with at least one traction motor and at least one brake of the rail vehicle. The on-board transceiver is configured to receive from an off-board control unit a first signal for establishing a rollback prevention mode. In its rollback prevention mode, the on-board transceiver is configured to receive from the off-board control unit a second signal indicative of a required tractive effort and a third signal indicative of a required braking force, and to control maintaining the required braking force until attaining the required tractive effort.
In embodiments, a system for controlling a rail vehicle includes an off-board control unit that is not mounted in the rail vehicle and an on-board transceiver that is mounted in the rail vehicle. The off-board control unit is configured to receive a first signal indicative of a location of the rail vehicle and to send, in response to the first signal, a second signal indicative of a minimum tractive effort parameter and a third signal indicative of a braking parameter. The on-board transceiver is operatively connected with at least one traction motor and at least one brake of the rail vehicle, and is configured to receive the second and third signals from the off-board control unit. The on-board transceiver is further configured to control maintaining the brake output at or above a level of the braking parameter until the traction motor output at least matches a level of the minimum tractive effort parameter.
The present invention will be better understood from reading the following description of non-limiting embodiments, with reference to the attached drawings, wherein below:
Reference will be made below in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference characters used throughout the drawings refer to the same or like parts. Although exemplary embodiments of the present invention are described with respect to rail vehicles within a rail yard, embodiments of the invention are also applicable for use with rail vehicles, generally.
When the rail vehicle consist 20 approaches the unloading equipment 16, each wagon 18 is in turn moved into position by indexing equipment 22. Once a wagon 18 is positioned, independent and/or automatic brakes are set to hold the rail vehicle consist 20 at a fixed location. (“Independent brakes” means the brakes of each locomotive or other powered rail vehicle 24 (rail vehicle capable of self propulsion) within the rail vehicle consist 20, which can be controlled independently of the “automatic brakes” that are installed on each wagon 18. The automatic brakes installed on the wagons 18 are operable all together and are also referred to as “train brakes.” Together, the independent and automatic brakes compose a “braking system,” which may be operated all together or piece by piece.)
In order to move the whole rail vehicle consist 20 forward, so as to bring a next wagon 18 into position, the brakes must be released while tractive power is applied when all or part of the rail vehicle consist 20 is located on a grade or incline, then rollback (as shown schematically in
Rollback of the rail vehicle consist 20, as illustrated schematically in
With reference to
As shown in
The displays 218, 228 and the OCU 220 are coordinated by a computing device 230. “Computing device” as used herein refers to either a general purpose integrated circuit, a custom ASIC, an FPGA, a custom analog circuit, or other like device. As shown in
As illustrated in
Each iteration of the process 400 includes a step 402 of checking and setting a mode of operation 403 of the off-board control unit 204. For example, pressing one of the STOP button 224 or the PARK button 226 establishes a corresponding mode of operation 403 of the off-board control unit 204 that causes the computing device 230 to generate and send to the on-board transceiver 202, via the tower transceiver 212, commands that idle the traction power system and that order braking of a locomotive 24 (or other powered rail vehicle) or of the entire rail vehicle consist 20, respectively.
After checking the mode of operation, the process 400 proceeds to a step 404 of receiving signals from the on-board transceiver 202 and/or from other sources within the rail yard 10 including the unloading equipment 16 or the indexing equipment 22. (Here “rail yard” is meant to include any arrangement of tracks off of a main line, including humpyards, sorting yards, or loading/unloading operations as discussed above.)
The computing device 230 stores received signals in the working memory 401 as on-board data 405. The on-board data 405 may include a measured speed “M” as well as indications that braking has been applied or that a braking order has been received in the rail vehicle where the on-board transceiver is installed. The measured speed “M” may be obtained by the on-board transceiver 202 from a control system on some rail vehicles (e.g., a locomotive control system on some locomotives) or from a trainline interface module (TIM) on some other locomotives or other rail vehicles.
Next, at a step 406 the computing device 230 generates commands 407 to be sent to the on-board transceiver. The commands 407 are generated according to an algorithm, which corresponds to the mode of operation 403. The algorithm generates the commands 407 with reference to the on-board data 405 and further with reference to control data and internal signals 408 that are stored in the working memory 401. Exemplary modes of operation 403, and on-board data 405, have been discussed above. The control data and internal signals 408 may include the braking parameter “P”, a preset speed limit “L”, a selector position “H”, and an ordered speed “O”. At a step 410 the tower control system 200 then sends the commands 407 to the on-board transceiver 202 before looping back to again check for control data input from the off-board control unit 204.
According to aspects of the present invention, the computing device 230 is configured to establish a rollback prevention mode of operation and to execute a first algorithm 500, as shown in
Still referring to
At step 512, the computing device 230 accesses the rollback prevention map 504, or an equivalent lookup table, to find a braking parameter 513 corresponding to the location 501. For example, the braking parameter 513 may be determined during commissioning of the tower control system 200. The computing device 230 then inserts into the commands 407 a signal that encodes the braking parameter 515.
At step 514 the computing device 230 receives from the multi-position selector 222 a signal ordering movement of the lead locomotive 24a (or other lead powered rail vehicle). The computing device 230 generates an ordered movement 515 and forwards a corresponding signal to the on-board transceiver 202. The computing device 230 then proceeds to step 516 of waiting to receive on-board transceiver status signals 601.
Referring to
In case the monitored movement 611 is matched with the ordered movement 515, then the on-board transceiver 202 declares a “movement” status signal at step 612. In case the monitored movement 611 does not match the ordered movement 515, then at step 614 the on-board transceiver 202 declares a “rollback” status signal and proceeds to apply automatic and independent brakes (“emergency braking”) at step 616.
In some embodiments, step 610 of checking for a match is accomplished by instantaneous or “snapshot” comparison of the directions of measured movement 611 and ordered movement 515. Thus, for example, in case the speed of ordered movement 515 is +0.5 mph (+0.2 m/s), while the monitored movement 611 is −0.2 mph (−0.09 m/s) (directions do not match), then a rollback is declared.
In other embodiments, step 610 is accomplished in a first noise-managed mode by comparing ordered movement 515 to monitored speed and direction 611 on a time integral basis, using one or more threshold value criteria. That is, referring to
Referring back to
Thus, in embodiments, a system for controlling a rail vehicle includes an off-board control unit that is configured for communication with an on-board transceiver, which is mounted in the rail vehicle. The off-board control unit is further configured to receive a first signal indicative of a location of the rail vehicle and to, in response to the indicated location of the rail vehicle matching a pre-defined list of rollback locations, send to the on-board transceiver a second signal indicative of a tractive effort parameter corresponding to at least the indicated location of the rail vehicle. In select embodiments, the system may also include the on-board transceiver, which may be configured to adjust and monitor a tractive effort of the rail vehicle and to control applying brakes of the rail vehicle until the monitored tractive effort at least matches the tractive effort parameter. In such embodiments, the off-board control unit also may be configured to set a braking parameter based on the indicated location of the rail vehicle and to transmit the braking parameter to the on-board transceiver, while the on-board transceiver may be configured to control applying the brakes according to the braking parameter. Further, the on-board transceiver may be configured to monitor rail vehicle movement, to compare the monitored movement to an ordered movement, and to control application of emergency brakes in response to a mismatch of the monitored movement and the ordered movement. For example, the on-board transceiver may be configured to control application of the emergency brakes according to the braking parameter. In select embodiments, the on-board transceiver may be configured to compare the monitored movement to the ordered movement on a time integral basis. In some embodiments, the on-board transceiver also may be configured to send to the off-board control unit, in response to a mismatch of the monitored movement and the ordered movement, a request for a third signal to apply the brakes of the rail vehicle. In such embodiments, the off-board control unit may be configured to, in response to the request received from the on-board transceiver, display an operator prompt and receive an operator input whether to apply the brakes. The third signal for applying the brakes may include a braking parameter based on the indicated location of the rail vehicle. Further, the off-board control unit may be configured to monitor tractive effort of the rail vehicle, and to send the on-board transceiver a fourth signal for releasing the brakes, once the tractive effort of the rail vehicle matches or exceeds the tractive effort parameter. However, in some embodiments, the off-board control unit may be configured to send the fourth signal for releasing the brakes, pursuant to a request received from the on-board transceiver. In some embodiments, the off-board control unit may be configured to send a fifth signal for establishing a rollback prevention mode, based on the indicated location of the rail vehicle matching the pre-defined list of rollback locations; the on-board transceiver may be configured to establish a rollback prevention mode on receipt of the fifth signal from the off-board control unit.
In aspects, a method, e.g., a method for preventing rollback of a rail vehicle from a stopped condition, includes receiving a first signal indicative of the rail vehicle's location and, in response to the first signal, selecting from a lookup table one of a first plurality of pre-determined values of a braking parameter and selecting from the lookup table one of a second plurality of pre-determined values of a tractive effort parameter. The method then includes transmitting to the rail vehicle a second signal ordering movement of the rail vehicle from the stopped condition. The second signal includes the selected value of the braking parameter for controlling application of brakes of the rail vehicle and the selected value of the tractive effort parameter for establishing tractive effort of the rail vehicle. In some aspects, the method also includes receiving the second signal at the rail vehicle, and, in response to the second signal, applying the brakes of the rail vehicle, according to the selected value of the braking parameter; establishing the tractive effort of the rail vehicle, according to the selected value of the tractive effort parameter; and, releasing the brakes of the rail vehicle to establish movement of the rail vehicle from the stopped condition. In certain aspects, the first signal is received at an off-board control unit that is not installed on the rail vehicle. In select aspects, the second signal is transmitted from the off-board control unit to an on-board transceiver that is installed on the rail vehicle.
Embodiments include a system for controlling a rail vehicle, which includes an on-board transceiver mounted in the rail vehicle and operatively connected with at least one traction motor and at least one brake of the rail vehicle. The on-board transceiver is configured to receive from an off-board control unit a first signal for establishing a rollback prevention mode. In its rollback prevention mode, the on-board transceiver is configured to receive from the off-board control unit a second signal indicative of a required tractive effort and a third signal indicative of a required braking force, and to control maintaining the required braking force until attaining the required tractive effort. The on-board transceiver may be further configured to control release of the braking force on attaining the required tractive effort, to monitor movement of the rail vehicle, to compare the monitored movement to an ordered movement, and to control application of the required braking force according to the third signal, in case the monitored movement does not match the ordered movement. In certain embodiments, the on-board transceiver may be configured to compare the monitored movement to the ordered movement on a time integral basis.
In other embodiments, a system for controlling a rail vehicle includes an off-board control unit that is not mounted in the rail vehicle and an on-board transceiver that is mounted in the rail vehicle. The off-board control unit is configured to receive a first signal indicative of a location of the rail vehicle and to send, in response to the first signal, a second signal indicative of a minimum tractive effort parameter and a third signal indicative of a braking parameter. The on-board transceiver is operatively connected with at least one traction motor and at least one brake of the rail vehicle, and is configured to receive the second and third signals from the off-board control unit. The on-board transceiver is further configured to control maintaining the brake output at or above a level of the braking parameter until the traction motor output at least matches a level of the minimum tractive effort parameter.
It will be appreciated that the invention is not limited by the preceding description, which is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the invention, they are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The scope of the invention should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, terms such as “first,” “second,” “third,” “fourth,” “fifth,” “upper,” “lower,” “bottom,” “top,” etc. are used merely as labels, and are not intended to impose numerical or positional requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. §122, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
This written description uses examples to disclose several embodiments of the invention, including the best mode, and also to enable one of ordinary skill in the art to practice the embodiments of invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to one of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
As used herein, an element or step recited in the singular and proceeded with the word “a” or “an” should be understood as not excluding plural of said elements or steps, unless such exclusion is explicitly stated. Furthermore, references to “one embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Moreover, unless explicitly stated to the contrary, embodiments “comprising,” “including,” or “having” an element or a plurality of elements having a particular property may include additional such elements not having that property.
Since certain changes may be made in the above-described system and method for rollback prevention, without departing from the spirit and scope of the invention herein involved, it is intended that all of the subject matter of the above description or shown in the accompanying drawings shall be interpreted merely as examples illustrating the inventive concept herein and shall not be construed as limiting the invention.
