Description RAILWAY VEHICLE STOPPING SYSTEM AND METHOD USING MAGNETIC PATTERNS Technical Field
[1] The present invention relates toa railway vehicle stopping system and method, and more particularly to a system and method for accurately stopping a railway vehicle using magnetic patterns, which allows a railway vehicle to automatically travel according to magnetic fields produced by magnets that are installed at specific intervals on a rail corridor between rails.
[2] Background Art
[3] Conventional methods of automatically guiding railway vehicles, which have been proposed up to now, are based on optics, radio communication, and magnetic fields.
[4] The optical-based automated guidance method uses a camera to capture images of the rail corridor of rails (i.e., images of the surface between the rails), and analyzes the captured images to determine the traveling direction or route of the railway vehicle on the rails. This method allows easy guidance control since it is possible to determine inadvance information of rails on which the railway vehicle will run.
[5] However, the optical-based automated guidance method cannot always expect clear railroad images due to rain or snow or other factors such as environmental pollutants in the air, and also requires a high-speed image processor, increasing implementation costs.
[6] The radio communication-based method has advantages in that it is negligibly influenced by weather or environmental conditions, and the receiver which is installed on the railway vehicle is relatively low-cost.
[7] Despite these advantages, the automated guidance method based on radio communication has a high risk of physical damage to transmitters installed on the railroad, and also entails high installation costs. It is also difficult to apply the radio communication-based system to the existing rails.
[8] The automated guidance method based on magnetic fields is also negligibly influenced by weather or environmental conditions. In addition, this method allows use of the existing rails, decreasing installation costs, and also provides high guidance control accuracy.
[9] However, conventional magnetic-based methods have employed little or no
redundant or fail-safe mechanisms for securing high safety of railway vehicles. It is also difficult for this method to stop a railway vehicle at a correct stop position since there is little or no information of rails on which the railway vehicle travels or will travel.
[10] Disclosure of Invention Technical Problem
[11] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide an economical railway vehicle stopping system and method that is not influenced by external factors such as weather or environmental conditions, and also allows the use of existing rails without alteration, thereby reducing system installation costs.
[12] It is another object of the present invention to provide a railway vehicle stopping system and method, which acquires the information of rails in advance through magnetic fields produced by magnets installed on the rail corridor of the rails, thereby increasing the safety of the railway vehicle.
[13] Technical Solution
[14] In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a railway vehicle stopping system using magnetic patterns, the system comprising redundant magnets placed on a rail corridor between rails of a railroad, the redundant magnets being arranged along each side of the rail corridor at predetermined intervals for continually producing magnetic signals along the rails; and four guide magnetic sensors provided in a railway vehicle for acquiring various continual information of the railroad in response to the magnetic signals produced by the redundant magnets, wherein the system measures speed of the railway vehicle based on time intervals at which magnetic signals are continually received through the guide magnetic sensors, and wherein the system accumulates the signals received through the guide magnetic sensors and compares the accumulated signals to guide the railway vehicle.
[15] Preferably, the redundant magnets are arrangedin two lines along each side of the rail corridor.
[16] Preferably, the guide magnetic sensors are placed on the railway vehicle at a front portion thereof to detect the magnetic signals produced by the redundant magnets.
[17] In accordance with another aspect of the present invention, there is provided arailway vehicle stopping system using magnetic patterns, the system comprising guide magnets arranged along a rail corridor between rails of a railroad for producing magnetic signals; and a guide magnetic sensor provided on a railway vehicle for detecting the magnetic signals produced by the guide magnets, wherein the system acquires various information of the rails based on the detected magnetic signals, and measures speed of the railway vehicle based on time intervals at which magnetic signals are continually received through the guide magnetic sensor, and the system accumulates the signals received through the guide magnetic sensor and compares the accumulated signals to guide the railway vehicle, the system further comprising at least four control magnetic sensors provided on the railway vehicle at a front portion thereof; and distance pattern magnets arranged on the rail corridor in at least four lines corresponding respectively to the at least four control magnetic sensors to communicate signals with the at least four control magnetic sensors, wherein using the control magnetic sensors and the distance pattern magnets, the system allows the railway vehicle running on the rails to measure a distance of the railway vehicle to a stop position.
[18] In accordance with still another aspect of the present invention, there is provided a railway vehicle stopping system using magnetic patterns, wherein the system guides a railway vehicle to a stop position, and measures adistance of the railway vehicle to the stop position for securing traveling safety of the railway vehicle, and wherein the system collects guide and distance information of the railway vehicle, and compares speed pattern signals produced by speed pattern magnets installed on a rail corridor with the collected guide and distance information, thereby measuring speed of the railway vehicle for decelerating or stopping the railway vehicle.
[19] In accordance with yet another aspect of the present invention, there is provided a railway vehicle stopping method in which distance and speed information of a railway vehicle is collected while guiding the railway vehicle, and a stop position and a stop time of the railway vehicle are determined based on the collected distance and speed information, the method comprising a track detection procedure comprising detecting speed and position of a railway vehicle running on rails, based on intensities of magnetic fields produced by redundant magnets arranged on a rail corridor at predetermined intervals along the rails, and determining whetheror not the railway vehicle runs along a correct path; a vehicle guidance procedure comprising analyzing the intensities of the magnetic fields produced by the redundant magnets and guiding the
railway vehicle to run along the correct path; a distance measurement procedure comprising detecting the position of the railway vehicle and measuring a stopping distance of the railway vehicle to a stop position where the railway vehicle is to be stopped; and a vehicle speed control procedure comprising calculating an accurate current speed and an accurate stopping distance of the railway vehicle after analyzing the measured stopping distance, and controlling the speed of the railway vehicle based on the calculation. [20] Advantageous Effects
[21] A railway vehicle stopping system and method using magnetic patterns according to the present invention has the following features and advantage. The system can be easily implemented by installing a simple arrangement of magnets on the railroad- without modification to the existing rails, so that no additional rail construction costs are incurred, thereby reducing system implementation costs. Furthermore, the system is easy to install and enables accurate guidance and stopping control of railway vehicles, thereby significantly increasing the safety and reliability of railway vehicles. Travel information of the railway vehicle such as the current speed and position thereof can be transmitted or received not only to and from the control center but also to and from related stations, so that the travel information can be displayed in the platforms of the stations, thereby allowing passengers waiting in the stations to view the travel information of railway vehicles of interest. The stopping system and method according to the present inventioncan be applied to any vehicle or any associated means.
[22] Brief Description of the Drawings
[23] The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
[24] Hg. 1 is a schematic diagram illustrating a system for stopping a railway vehicle using magnetic patterns according to the present invention
[25] Hg. 2 is a schematic diagram illustrating magnetic patterns for guiding railway vehicles to run along a correct path in the railway vehicle stopping system according to the present invention
[26] Hg. 3 is a schematic diagram illustrating magnetic patterns provided on the rail
corridor of rails and magnetic sensors provided in a railway vehicle, according to the present invention;
[27] Hg. 4 is a graph illustrating outputs of magnetic sensors provided in a railway vehicle when the railway vehicle runs normally, according to the present invention
[28] Hg. 5 illustrates outputs of guide magnetic sensors provided in a railway vehicle when the railway vehicle travels normally, according to the present invention
[29] Hg. 6 illustrates outputs of the guide magnetic sensors when the railway vehicle travels abnormally, e.g., while deviating to the right;
[30] Hg. 7 illustrates outputs of the guide magnetic sensors when the railway vehicle travels abnormally, e.g., while deviating to the left;
[31] Hg. 8 is a graph illustratingthe speed of a railway vehicle when the railway vehicle stops normally under the control of the railway vehicle stopping system according to the present invention; and
[32] Hg. 9 is a flow chart illustrating how the railway vehicle stopping system controls the railway vehicle to stop.
[33] Best Mode for Carrying Out the Invention
[34] Nbw, preferred embodiments of the present invention will be described in detail with reference to the annexed drawings. In the drawings, the same or similar elements are denoted by the same reference numerals even though they are depicted in different drawings.
[35] Hg. 1 is a schematic diagram illustrating a system for stopping a railway vehicle using magnetic patterns according to the present invention. As shown in Hg. 1, according to the present invention, a railway vehicle 10 includes guide magnetic sensors 13 for detecting magnetic fields produced by redundant magnets 12, which are arrangedon the surface of a rail corridor under and between rails 11 at specific intervals, in order to guide the railway vehicle 10 to travel along a correct path.
[36] A railway vehicle stopping system (or an automated train guidance system) according to the present invention will now be described in detail with reference to Rgs. 2 to 4. The railway vehicle stopping system includes redundant magnets 12, which are arranged on the rail corridor at both sides thereof at predeterminedintervals, and continually emit specific-strength magnetic fields to a railway vehicle 10 running on the rails. The railway vehicle stopping system also includes four guide magnetic sensors 13 provided on the railway vehicle 10, which sensitively respond to magnetic signals emitted from the redundant magnets 12 and detect various continual in-
formation of the rails 11. The railway vehicle stopping system measures the speed of the railway vehicle 10 based on time intervals at which magnetic signals are continually received through the guide magnetic sensors 13. The railway vehicle stopping system accumulates the signals received through the guide magnetic sensors 13 and compares the accumulated signals to guide or direct the railway vehicle 10. [37] The rails 11, on which the railway vehicle 10 travels, are general rails but the redundant magnets 12 are arranged along the rail corridor of the rails 11 at predetermined intervals. For example, the redundant magnets 12 may be permanent ferrite 07 magnets having a magnetic dipole moment of 9.585x10 Weber/Am.
[38] The redundant magnets 12 are arrangedin at least two lines along each side of the rail corridor. The redundant magnets 12 are combined to form a guide pattern 12a for guiding the railway vehicle 10.
[39] The purpose of installing the redundant magnets 12 in the above manner is to prepare for the occurrence of a failure or malfunction in one of the two redundant magnets 12 arranged on the rail corridor at one side thereof or in one of the two guide magnetic sensors 13 installed on the railway vehicle 10 at one side thereof.
[40] The magnets of the guide pattern 12a are preferably arranged at intervals of a predetermined distance to avoid the influence of external factors.
[41] In addition, the guide magnetic sensors 13 are installed on the railway vehicle 10 at a front lower portion thereof in order to sense the strength of the magnetic field produced by the redundant magnets 12. The guide magnetic sensorl3 is a three-axis magnetic sensor for outputting three orthogonal magnetic sensing signals corresponding to x, y and z positional values of the sensor 13 with respect to the corresponding redundant magnet 12. The number of lines in which the redundant magnets 12 are arranged is preferably equal to the number of the guide magnetic sensors 13.
[42] The x positional value corresponds to the distance of the guide magnetic sensor 13 from the redundant magnet 12 along the x axis parallel to the longitudinal direction of the rails 11, the y positional value corresponds to the horizontal distance of the guide magnetic sensor 13 from the redundant magnet 12 along the y axis, and the z positional value corresponds to the height of the guide magnetic sensor 13 from the redundant magnet 12 along the z axis.
[43] The magnetic intensity B of a magnet with respect to x, y and z positional values can be expressed by the following equation.
[44]
U-** - ' 3 a [ ]
,(1) [45] Here, "U" denotes magnetic potential, "r" is
, "M" denotes magnetic moment, and "μ " denotes magnetic permeability. o
[46] The magnetic field H and the magnetic intensity B have the following relationship.
[47] H „ = -( ,du ar + du α„ + du or,) As m\ dx * dy γ dz Σ
,(2)
[48]
,(3) [49] Using Equations (1) to (3), the magnetic field H and the magnetic intensity B can be calculated as follows.
[50] H = M j(3jz-?y + 3 g-jJ,+ (2z2- 7?-y2) s)[Afm] 4πμϋr ,(4)
[51] B = + 3yza + (2z
2 - ?? - y
2)
s)[wb 1
' m
2}
,(5) [52] Using Equations (4) and (5), the x-axis magnetic intensity component B , the y-axis magnetic intensity component B , and the z-axis magnetic intensity component B can y z be obtained as follows.
[53] r βx ,(6)
[54] r y
, (7)
4π and "a" denotes a unit conversion factor.
[57] The guide magnetic sensors 13 are placed on the railway vehicle at a front portion thereof so as to receive magnetic signals emitted from the redundant magnets 12. The guide magnetic sensors 13 are used to obtain information of the rails 11 and then to guide the railway vehicle 10 to travel along a correct path.
[58] When the railway vehicle 10 runs on the rails 11, the redundant magnets 12 and the guide magnetic sensors 13 communicate signals to guide the railway vehicle 10 as described below.
[59] If the railway vehicle 10 runs on the rails 11 along the redundant magnets 12, which are arranged on the rail corridor, preferably, at both sides thereof, the guide magnetic sensors 13 placed in the railway vehicle 10 output signals of specific waveforms as shown in Hg. 4 as time passes. A guidance value (for example, a travel distance) of the railway vehicle 10 can be obtained by dividing the number of waves of the output signals of the guide magnetic sensors 13 by time.
[60] In order to accomplish this, the redundant magnets 12 need to be arranged at predeterminedintervals along the rails 11. The redundant magnet 12 produces a specific- intensity magnetic field (B , B , B ) as described above. Each of the guide magnetic x y z sensors 13 detects the produced magnetic field and outputs a corresponding signal having a specific waveform. It is possible to determine the travel distance or location of the railway vehicle 10 by analyzing the output signals of the guide magnetic sensors 13 on a time basis, and it is possible to determine traveling direction (i.e., guidance angle), in which the railway vehicle 10 runs, by counting the respective waves of the output signals of the guide magnetic sensors 13. [61] Hg. 5 illustrates the intensities of magnetic fields (shown on the left side) produced by the redundant magnets 12 and magnetic field detection signals (shown on the right side) output from left and right-side guide magnetic sensors 13 when the railway vehicle 10 travels normally. Here, the left-side guide magnetic sensors 13 refer to two
guide magnetic sensors 13 installed on the railway vehicle 10 at the left side thereof, and the right-side guide magnetic sensors 13 refer to the other two guide magnetic sensors 13 installed on the railway vehicle 10 at the right side thereof. It can be seen from Hg. 5 that the output signals of the left and right-side guide magnetic sensors 13 have the same waveforms when the railway vehicle 10 travels normally.
[62] Hg. 6 illustrates the waveforms of the output signals of the left and right-side guide magnetic sensors 13 in the railway vehicle 10 when the railway vehicle 10 travels on the rails 11 abnormally, e.g., while deviating to the right. It can be seen from Hg. 6 that the railway vehicle 10 deviates to the right if the right-side guide magnetic sensors 13 placed on the right side have a larger output level than the left-side guide magnetic sensors 13 placed on the left side.
[63] That is, the output waveform levels of the guide magnetic sensors 13 vary depending on the side to which the center of the guide magnetic sensors 13 deviate from the center of the redundant magnets 12. Accordingly, the steering angle of the railway vehicle 10 can be set based on the analysis of the different output waveforms of the left and right-side guide magnetic sensors 13.
[64] Hg. 7 illustrates the waveforms of the output signals of the left and right-side guide magnetic sensors 13 in the railway vehicle 10 when the railway vehicle 10 travels on the rails 11 abnormally, e.g., while deviating to the left. It can be seen from Hg. 7 that the railway vehicle 10 deviates to the left if the left-side guide magnetic sensors 13 placed on the left side have a larger output level than the right-side guide magnetic sensors 13 placed on the right side. That is, it can be seen from Hgs. 6 and 7 that the railway vehicle 10 deviates to the side on which the guide magnetic sensors 13 having a larger output level are placed.
[65] Experimental results have shown that controlling or changing the steering angle when the output levels of the left and right-side guide magnetic sensors 13 are slightly different reduces the ride comfort of the railway vehicle 10 and also decreases the control efficiency. Accordingly, a threshold difference between the output levels of the left and right-side guide magnetic sensors 13 must be preset to a suitable value, taking into account the ride comfort and the control efficiency.
[66] In addition, according to an embodiment of the present invention, in order to accurately measure and detect stopping distance and stopping speed of the railway vehicle for accurate stopping thereof, not only the magnets of the guide pattern 12a but also distance pattern magnets 14 and speed pattern magnets 15 are provided on the inter-rail road as shown in Hg. 3, and control detection sensors 16 are provided in the
railway vehicle for detecting magnetic signals from the distance pattern magnets 14 and the speed pattern magnets 15.
[67] In this embodiment, the guide magnetic sensors 13 and the control detection sensors 16 have specific- waveform outputs as shown in Hg. 4.
[68] That is, the control detection sensors 16 output a control pattern detection signal 17 having a waveform as shown between waveforms of the output signals 18 of the guide magnetic sensors 13.
[69] The stop position ofthe railway vehicle 10 cannot be determined if there is no information on the traveling direction of the railway vehicle 10. The output waveform of the control pattern detection signal 17 must be analyzed to obtain an accurate stop position of the railway vehicle 10.
[70] More specifically, as shown in Hg. 3, four distance pattern magnets 14 and four speed pattern magnets 15 are sequentially arranged in parallel on the rail corridor at a middle portion thereof along the rails 11, and four control detection sensors 16 are installed on the railway vehicle 10 at a front portion thereof to detect magnetic signals produced by the magnets 14 and 15.
[71] As described in Korean Patent Application Nb. 2004-0017263 filed by the present applicant, the current position and speed of the railway vehicle 10 are determinedby comparing and analyzing on a time basis the waveforms of output signals of magnetic sensors provided in the railway vehicle 10 in response to magneticfields produced by the distance pattern magnets 14 and the speed pattern magnets 15, thereby obtaining information of the distance of the railway vehicle 10 to the stop position and the approach speed thereof.
[72] Accordingly, the railway vehicle 10 guided according to the guide pattern 12a can approach the stop position while gradually decreasing its speed, thereby achieving reliable and accurate stopping.
[73] According to the present invention, distance and speed control patterns according to the present invention, which correspond to the control pattern detection signal 17 in Rg. 4, are determined based on preset pattern control information as shown in Tables 1 and 2.
[74]
[75]
[76] Table 1 stopping distance information according to control pattern
[77] [78] Table 2 speed control information according to control pattern
[79] [80] The four control detection sensors 16 detect magnetic signals produced by the distance pattern magnets 14 and the speed pattern magnets 15, and output digital pattern signals having four binary values of Is and 0s according to the control patterns of the magnets 14 and 15. The digital pattern signals output from the control detection sensors 16 are compared with predetermined speed and distance control information as shown in Tables 1 and 2, and the movement of the railway vehicle 10 is controlled based on the comparison.
[81] The digital pattern conversion tables (i.e., Tables 1 and 2) are preferably determined according to the characteristics of the railway vehicle 10 that runs on the rails 11. In addition, an appropriatethreshold output level must be preset for the control detection sensors 16, so that only if the level of a signal output from a control detection sensor 16 in synchronization with a guide pattern signal output from the guide magnetic sensors 13 is higher than the preset threshold output level, is it determined that the output signal of the control detection sensor 16 is present.
[82] A method for stopping a railway vehicle under the control of the railway vehicle stopping system configured as described above will now be described in detail. Hg. 8 is a graph illustratingthe speed of a railway vehicle when the railway vehicle stops normally under the control of the railway vehicle stopping system, and Hg. 9 is a flow chart illustrating how the railway vehiclestopping system controls the railway vehicle to stop.
[83] In the railway vehicle stopping method, the railway vehicle stopping system collects distance and speed information of a railway vehicle 10 while guiding the
railway vehicle 10, and determines a stop position and a stop time of the railway vehicle 10 (i.e., when and where the railway vehicle 10 is to be stopped) based on the collected information.
[84] Specifically, the railway vehicle stopping method according to the present invention is performed in the following manner. The railway vehicle stopping system first performs a track detection procedure in which the system detects the speed and position of a railway vehicle running on rails, based on intensities of magnetic fields produced by redundant magnets, which are arranged in two lines on a rail corridor at predeterminedintervals along the rails, and determines whether or not the railway vehicle runs along a correct path (SI 00).
[85] After the track detection procedure, the railway vehicle stopping system performs a vehicle guidance procedure in which the system analyzes the intensities of the magnetic fields produced by the redundant magnets and guides the railway vehicle to run along the correct path (S200).
[86] After the vehicle guidance procedure, the railway vehiclestopping system performs a distance measurement procedure in which the system detects the position of the railway vehicle and measures a stopping distance of the railway vehicle, which is the distance of the railway vehicle to a stop position where the railway vehicle is to be stopped (S300).
[87] After analyzing the stopping distance measured at step S300, the railway vehicle stopping system performs a vehicle speed control procedure in which the system calculates an accurate current speed and an accurate stopping distance of the railway vehicle, and controls the speed of the railway vehicle based on the calculation (S400).
[88] More specifically, in the track detection procedure (S100), the railway vehicle stopping system detects the speed and positionof a railway vehicle running on the rails, using detected intensities of magnetic fields produced by the redundant magnets, which are arranged in two lines on a rail corridor at predetermined intervals along the rails.
[89] In the track detection procedure (S 100), the railway vehicle stopping system transmits and receives speed and position information of the railway vehicle to and from a control center (not shown) at intervals of one second or less to determine the distance of the railway vehicle to the stop position.
[90] After the track detection procedure, the railway vehiclestopping system guides the railway vehicle 10 to travel along the correct rails in the vehicle guidance procedure (S200). In this procedure, the system sets accurate steering angles of the railway
vehicle for accurate stopping and guidance thereof.
[91] In the distance measurement procedure (S300), the railway vehicle stopping system accurately measures the stopping distance of the railway vehicle 10 guided through the accurate steering angle control (i.e., measures the distance of the railway vehicle 10 to the stop position) and prepares to reduce the speed of the railway vehicle for stopping thereof.
[92] Here, the stopping distance of the railway vehicle 10 is determined taking into account the characteristics of the railway vehicle 10 and conditions of the rails 11 such as the slope of the rails 11 or conditions of the rail corridor of the rails 11.
[93] The railway vehicle stopping system then performs the speed control procedure (S400) in which the system transmits a speed control signal to the railway vehicle 10 to control the speed of the railway vehicle to ensure the calculated stopping distance as a safe distance to the stop position. If there is no need to ensure a safe distance to the stop position, the speed control of this procedure is not performed.
[94] The deceleration rate of the railway vehicle is set differently depending on the stopping distance, and the railway vehicle is carefully decelerated avoiding full braking, taking into account the ride comfort.
[95] As apparent from the above description, a railway vehicle stopping system and method using magnetic patterns according to the present invention has the following features and advantage. The system can be easily implemented by installinga simple arrangement of magnets on the railroad, without modification to the existing rails, so that no additional rail construction costs are incurred, thereby reducing system implementation costs. Furthermore, the system is easy to install and enables accurate guidance and stopping control of railway vehicles, thereby significantly increasing the safety and reliability of railway vehicles. Travel information of the railway vehicle such as the current speed and position thereof can be transmitted or received not only to and from the control center but also to and from related stations, so that the travel information can be displayed in the platforms of the stations, thereby allowing passengers waiting in the stations to view the travel information of railway vehicles of interest. The stopping system and method according to the present inventioncan be applied to any vehicle or any associated means.
[96] Although the preferred embodiments of the present invention have been disclosed for illustrative purposes,those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Accordingly, the
scope of the present invention should not be limited to the above embodiments, but should rather defined by the accompanying claims as well as equivalents thereof. Industrial Applicability
[97] The present invention relates toa railway vehicle stopping system and method, and more particularly to a system and method for accurately stopping a railway vehicle using magnetic patterns, which allows a railway vehicle to automatically travel according to magnetic fields produced by magnets that are installed at specific intervals on a rail corridor between rails.
[98]
[99]