Background
At present, a maglev train is a novel vehicle which is mainly developed in China after high-speed railways, has the advantages of low energy consumption, high speed, strong climbing capability, safety, intelligence, riding comfort and the like, and accords with the development trend of green, safety and intellectualization of modern vehicles. Therefore, the maglev train is used as a first-choice system for developing a new generation of ground transportation means in the future, and has great strategic significance for social and civilian life, economic development, urban layout and the like.
Many technical methods for measuring and positioning the speed of the magnetic suspension train at home and abroad are available, such as: the method comprises the steps of crossing loop line speed measurement positioning, Doppler radar speed measurement positioning, microwave speed measurement positioning, inter-rail cable speed measurement positioning, distance measurement and beacon integrated speed measurement positioning and the like. In China, a crossing loop speed measurement positioning method is mostly adopted for medium and low speed maglev trains. However, magnetic levitation trains are equipped with strong magnetic field subsystems such as a levitation system, a guidance system, and a propulsion system, which have a certain degree of electromagnetic interference with each other. The crossing loop speed measurement positioning method is based on train position identification of a magnetic field generated by loops, and factors such as electromagnetic fields of a suspension system, a guide system and a propulsion system, installation errors, train operation vibration and the like can influence the positioning precision of the crossing induction loop speed measurement positioning system.
With the steady promotion of the state on the technical innovation of rail transit and the industrialization of key technical equipment, the development targets of green, safe and intelligent railway equipment become clearer, and the vigorous development of the related technology of the magnetic suspension train is one of the important future development directions. The advanced rail transit special item of the national key research and development plan supports medium and high speed maglev train projects with the speed per hour of 200 km/h and 400 km/h, and a new generation high speed maglev train project with the speed per hour of 600 km/h is started. The system has higher precision and intelligent control requirements on the existing systems of train suspension, propulsion, guidance and the like, and is a serious challenge and an inexhaustible development opportunity for the related technologies in the field. Meanwhile, the magnetic suspension train has the advantages of complex structure, large control difficulty, high intelligent degree and large data volume, and the existing train positioning and speed measuring technology is difficult to be competent for the high-speed magnetic suspension train.
Train positioning and speed measuring technology is also an important basis for realizing the operation control and the running scheduling of the magnetic suspension train. Particularly, for a magnetic suspension train driven by a long stator synchronous linear motor, the excitation control of an armature winding of the magnetic suspension train is closely related to the positioning of the train, and the reliable control of the long stator synchronous linear motor is not realized without an accurate positioning technology.
On the other hand, the current train energy-saving operation and intelligent control technology needs train overspeed protection (ATP), Automatic Train Operation (ATO), automatic train monitoring (ATS) and other systems with complete functions. These systems all need accurate, efficient and reliable train positioning and speed measuring technologies as a basis. Without accurate train positioning and speed measuring technology, the advanced optimization algorithm can not achieve the expected effect.
In conclusion, the advantages of the magnetic levitation technology are fully exerted, the competitiveness of the magnetic levitation train is improved, the energy-saving running and intelligent control of the train are further achieved, and the accurate, efficient and reliable train positioning and speed measuring technology has important significance.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the magnetic suspension train is positioned and tested in a trackside beacon positioning mode, the positioning and speed testing accuracy of the train is improved, and the running condition of the train is effectively monitored.
In order to achieve the technical aim, the invention provides a three-dimensional magnetic coding type train positioning identification method which is small in size, high in reliability and simple in coding by adopting a trackside beacon positioning mode.
In order to achieve the technical goal, the invention specifically adopts the following technical scheme:
the three-dimensional magnetic code adopts a three-layer structure: comprises a base, an information coding layer and a protective layer; the upper part of the information coding layer comprises a position detection area and an information identification area, the position detection area is used for calibrating the position of the magnetic code area, the information identification area is used for storing information, and the lower part of the information coding layer adopts an n x j matrix sequence; the method comprises the following steps:
(1) and (3) data analysis: determining the type of coded characters and the specification of three-dimensional magnetic codes, and converting the coded characters into data characters according to a character set;
(2) and (3) data encoding: converting the data characters into bit streams, directly converting decimal landmark data into ternary data sequences to form a data code word sequence for matrix coding, and then identifying and reading the three-dimensional magnetic code data code word sequence by a decoder to obtain the data content of the three-dimensional magnetic code;
(3) error correction coding: arranging the data code word sequence in a partitioning mode, adding error correction code words into the data code word sequence to form new sequence information, and adding appended surplus sequence information at the tail of the new sequence information;
(4) constructing a matrix: putting modules of detection information, positioning information, additional information and code words in the sequence generated in the step (3) into a matrix sequence;
(5) format and version information: putting the format and version information in the sequence generated in the step (3) into an information identification area to generate a final three-dimensional magnetic code;
(6) when the train passes through the three-dimensional magnetic code, the magnetic pole information of the three-dimensional magnetic code is read, the read information is sent to the vehicle-mounted control unit, and the vehicle-mounted control unit decodes the information to obtain the real-time state information of the train.
Preferably, the three-dimensional magnetic code magnetic pole information reading method in the step (6) is that when the train passes through the three-dimensional magnetic code, a matrix sequence of the three-dimensional magnetic code is scanned through a vehicle-mounted induction coil, and a vehicle-mounted sensor detects induced electromagnetic wave pulses generated by the induction coil in the scanning process and transmits the detected information to a vehicle-mounted control unit; and the vehicle-mounted control unit judges the polarity of the magnetic pole according to the direction of the pulse wave, performs decoding operation, converts the decoded sequence into a binary computer language, calls the responded road sign information from the established information database, finally obtains the train displacement through adjacent monitoring points, obtains the running speed by deriving the train displacement, and obtains the train acceleration by deriving the running speed.
Preferably, the road sign information is matrix-combined encoded through three code elements of permanent magnetic poles 'N', 'S' and non-magnetic '0' vacancy according to the matrix sequence.
Preferably, the protective layer is made of a non-magnetic material and covers the surface of the information coding layer.
Preferably, the position detection zone is formed by nesting a large square magnetic pole ring and a square magnet.
Preferably, the base attaching surface is frosted.
Preferably, the base and the information coding layer are fixed by rivets or grooves, and the edges of the magnetic codes are rounded.
Preferably, the protective layer is provided with an information calibration part which can identify serial numbers and installation position information.
The invention has the following beneficial effects:
the invention realizes the accurate positioning of the magnetic suspension train based on the trackside beacon mode, realizes the storage of the track position information through the different arrangement sequences of the three code elements, and has the advantages of simple coding, quick reading, strong adaptability and the like. Train running speed can be obtained by deriving the displacement, and train acceleration can be obtained by deriving the running speed. The accurate monitoring of the position, the speed and the acceleration of the train provides a basic basis for the energy-saving operation and the intelligent control of the train.
Detailed Description
The three-dimensional magnetic encoding method and the application technology thereof in the fields of positioning and speed measurement of the magnetic suspension train are key technologies related to excitation of a stator winding of the magnetic suspension train, traction matching, energy-saving operation and the like. With the rapid development of the rail transit system towards the green, safe and intelligent directions, higher requirements are provided for the train positioning technology, such as information acquisition speed, information accuracy and the like. The invention monitors the state information of the position, the speed, the acceleration and the like of the magnetic suspension train by adopting a three-dimensional magnetic coding identification method based on an information calibration method, and provides a basic basis for the accurate control of the magnetic suspension train.
The three-dimensional magnetic code identification method adopts the 'N', 'S' polarity and the non-magnetic '0' vacancy of the permanent magnet to form a basic code element in an information coding area, and carries out information coding storage according to a preset matrix coding mode.
The core part of the three-dimensional magnetic code is the information encoding mode of the encoding layer and the reading strategy of the three-dimensional magnetic code.
The three-dimensional magnetic code magnetic pole encoding process comprises the following steps:
(1) and (3) data analysis: determining the type of coded characters and the specification of three-dimensional magnetic codes, and converting the coded characters into symbolic characters according to a corresponding character set; under the condition of a certain specification, the higher the error correction level is, the smaller the real data capacity is.
(2) And (3) data encoding: and converting the data characters into bit streams, directly converting the decimal landmark data into a ternary data sequence to form a data code word sequence for matrix coding so as to carry out efficient decoding, and then identifying and reading the three-dimensional magnetic code data code word sequence by a decoder to obtain the data content of the two-dimensional code.
(3) Error correction coding: the code word sequence is arranged according to the needed partition, in order to realize higher fault-tolerant rate of the magnetic code, an error correction code word needs to be added in a coding region, the error correction code word is added into the data code word sequence to form new sequence information, and in addition, the appended surplus sequence information is added at the end of the sequence.
(4) And (3) constructing final data information: the sequences generated above are put into blocks in order, subject to specification.
(5) Constructing a matrix: and putting the detection information, the positioning information, the additional information and the code word module into a corresponding matrix.
(6) Format and version information: and the generated format and version information are put into a corresponding information identification area to generate the final three-dimensional magnetic pole three-dimensional magnetic code.
The invention provides a train control system, which can acquire the relevant information of train operation and provides a basic technology for realizing the intelligent driving of future trains.
For more clear explanation of the present invention, an information database with decimal values ranging from 0 to 1320000 is established based on the following about 1320 km in the total length of the track from beijing south station to shanghai rainbow bridge station, and the present invention encodes the values '2', 1 'and 0' in ternary numerical manner using the magnetic poles 'S', 'N' and '0' respectively
The coding mode of the invention can also adopt the coding modes of letters, characters, Chinese characters and the like, and the basic method is consistent with the digital mode and is not described more.
The indicator is digitally encoded to be 0001. data 1234567 is encoded in the [0-1320000] information database for example.
1. And (3) data analysis: the Beijing to Shanghai rail transit line is usually 1320 kilometers, train positioning detection points are set for one meter according to the distance, 1320001 identification information sequences are required in the whole line, the requirement can be met by using ternary numerical values in a matrix with the size of 15 multiplied by 10 in the coding region, in addition, the high level of error correction is realized by adopting a three-dimensional magnetic code repeated sequencing means, and the accuracy of the three-dimensional magnetic code is ensured.
2. Numerical conversion ternary: 1234567 → 2022201111201
Adding 4-bit mode indicator (0001) before the real numerical value sequence facilitates storing coding mode and additional information, and additionally adding eight-bit character at the end of the numerical value sequence to set as an affix information sequence (00000001).
3. Adding a symbol sequence: 0001202220111120100000001
In order to improve the fault-tolerant rate of the three-dimensional magnetic code and avoid decoding errors, an error correction sequence is added in the coding sequence, and the three-dimensional magnetic code elements are repeatedly arranged to form a new sequence.
And (3) error correction processing: a set of ternary sequences of 5 × 10 is formed as described above, and then error correction processing is performed, that is: the 5 × 10 ternary sequence is repeated and added to the coding sequence to assemble a final 15 × 10 coding sequence. Wherein, a group of ternary sequences is represented as:
0000 0011 2200 2222 2200 1111 1111 2200 1100 0000 0000 0000 11
supplemental additional information bits: the added information identification module and the magnetic code position detection module are obtained, as shown in fig. 1.
The three-dimensional magnetic code magnetic pole information reading process comprises the following steps:
acquiring an information sequence: the train recognizer recognizes and reads the three-dimensional magnetic code data code word sequence to obtain the road sign information sequence.
The method comprises the steps that induction coils in one-to-one correspondence relation between vertical rows (vertical to the ground) and three-dimensional magnetic code magnetic codes are adopted, when a train passes through the three-dimensional magnetic codes, the vertical rows of induction coils sequentially scan according to a single-row matrix array, induction electromagnetic waveforms generated by the induction coils in the scanning process are detected by a sensor, and a control system is transmitted to read and store information sequences of the magnetic codes (electromagnetic waves generated by a magnetic pole S can be set to be positive pulses, electromagnetic pulses generated by a magnetic pole N are reverse pulses, and no electromagnetic waveform is '0' vacant site); in addition, the position detection area adopts the nested rectangular ring to generate a pulse signal obviously different from the coding area, so that a decoder can conveniently identify and recognize the three-dimensional magnetic code, the interference and the misreading of an external magnetic object are avoided, and the small-size magnetic code is adopted due to the small area of the information identification area, so that the coding mode of the coding area and the capacity of format information storage are met.
Three-dimensional magnetic code reading: and the control system restores the three-dimensional magnetic code matrix sequence to the information sequence.
The strategy control system judges the magnetic pole polarity records according to the direction of the pulse wave to sequentially complete the control sequence set by the system, the decoding operation is carried out according to the decoding mode set by the system, then the decoding operation is converted into the binary computer language, the system directly calls the road condition information responded from the established information database, then accurate position information is provided for the train control system, in addition, the train running displacement is obtained through adjacent monitoring points, then the running speed can be obtained by carrying out derivation on the train displacement, and the train acceleration can be obtained by carrying out derivation on the running speed. And then, the aim of accurately monitoring the position, the speed and the acceleration of the train is achieved, and a technical basis is provided for the energy-saving operation and the intelligent control of the train.
Note that: the specific reading method is described here, but the present invention is described in more detail without any specific reading method.
The invention comprises three parts according to the description of the attached drawings: a base, an information encoding layer 8, and a magnetic code protection layer 2/9. The magnetic code protective layer 2/9 directly covers the information coding layer 8 to form a whole, and protects the magnetic codes of the information coding layer 8 to prevent the magnetic codes from falling off, being damaged or demagnetizing; in the information coding layer 8, the road sign information is coded by three code elements of permanent magnetic poles 'N', 'S' and non-magnetic '0' vacancy, so as to be stored in a preset magnetic code sequence consisting of magnetic codes. The position detection area 6/9 is used for calibrating the position of the magnetic code area, so that the vehicle-mounted probe can conveniently decode code scanning information and ensure accurate reading. The information identification area 7 is used for storing information such as format, version, zero position and the like of the three-dimensional magnetic code.
The three-dimensional magnetic code is provided with a position detection area 6/10 and an information identification area 7 in an information coding area, which are respectively formed by nesting square magnetic pole rings and square magnets, and magnetic sheets with the sizes different from the code element size of the coding area are arranged according to a preset specific matrix sequence format. The position detection region 6/10 is used for identifying and reading the magnetic code region, determining the scanning position of the decoder, improving the anti-interference capability and ensuring the decoder to accurately identify and read; the information identification area 7 is used for storing information such as format, version, zero position and the like of the three-dimensional magnetic code.
The base 5 and the information coding layer 8 are fixed by rivets or grooves, and the edge 1 of the magnetic code can be rounded.
The magnetic code protective layer 2/9 of the patent is provided with an information calibration part 4 which can identify information such as serial numbers, installation positions and the like, and is convenient for engineering installation and maintenance and the like.
The three-dimensional magnetic coding comprises coding information and fault-tolerant information of the position. The position is an absolute position, and the mutual influence and the accumulative error cannot occur.
The magnetic code layer code element comprises three types of magnetic poles 'N', magnetic poles 'S' and non-magnetic vacant positions. The magnetic poles are realized by axially magnetized round magnetic sheets (the round magnetic sheets can be made of cylindrical magnetic slices, and the thickness, excitation and the like can be specifically adjusted according to actual requirements).
The magnetic code element made of the rare earth permanent magnetic material has the advantages of strong magnetism, high positioning precision, high identification and reading performance, difficult demagnetization, small size of the three-dimensional magnetic code and the like.
The surface of the coding layer of the three-dimensional magnetic code is covered with a non-magnetic material to prevent the magnetic code from falling off and being damaged, and the three-dimensional magnetic code has the function of preventing the magnetic performance of the magnetic code element from declining due to oxidation, corrosion, impact and the like, and the service life is prolonged.
The three-dimensional magnetic code can be normally used in various severe environments such as large dust, poor light, low temperature, rain and snow weather and the like, and has a certain protection function.
The mark adopts dull polish to handle in the base design, ensures that three-dimensional magnetic code firmly pastes, improves the reliability.
The three-dimensional magnetic code is provided with an information identification part on the surface of the protective layer, and can identify information such as a serial number, a mounting position and the like, so that engineering installation, maintenance and the like are facilitated.
As mentioned above, the method adopts the trackside beacon positioning method to position and measure the speed of the magnetic suspension train, and the preset detection positions are orderly adhered and fixed along the track of the magnetic suspension train according to the set distance (the specific distance is determined according to the actual situation).
According to the above description, the corresponding position of the maglev train is provided with the vehicle-mounted probe for corresponding scanning, decoding and monitoring. The train can read the prestored information when scanning one three-dimensional magnetic code, and then the train operation position information can be obtained. Train running speed is obtained by deriving the displacement, and train acceleration is obtained by deriving the running speed. The accurate monitoring of the position, the speed and the acceleration of the train provides a basic basis for the energy-saving operation and the intelligent control of the train.