A distributed testing system and method for a braking system

Abstract

The present invention discloses a distributed test system and method for a brake system, wherein the distributed test system comprises: an intelligent detection terminal for collecting test data and sending the collected test data to a wireless intelligent gateway via wireless transmission; a wireless intelligent gateway for receiving the test data sent by the intelligent detection terminal and sending the test data to a database via 5G communication; and a host computer, wherein the host computer is provided with host computer software, and the host computer software is used for remote access, test configuration, real-time monitoring, and automatic analysis and processing of the test data in the database. This application applies WIFI-based wireless sensor network technology to a rail vehicle test system, reduces the use of a large number of cables through wireless data transmission, reduces the requirements for the on-site environment, reduces the installation cost of test equipment, and reduces safety hazards.

Description

Technical Field

[0001] The present invention relates to the technical field of train brake detection, and in particular to a distributed testing system and method for a brake system. Background Art

[0002] According to the requirements of GB / T 14894-2005 "Rules for Inspection and Testing of Urban Rail Transit Vehicles after Assembly" and IEC_61133-2006 "Specifications for Vehicle Testing before Assembly and Operation", after the brake system is installed on the vehicle, a line test is required to evaluate the operating performance of the vehicle's brake system by collecting parameters such as control commands, brake cylinder pressure, brake shoe / brake pad braking force, electric brake force, acceleration, vehicle speed and thermal capacity during driving. This involves joint testing of the vehicle, traction system and network system.

[0003] At present, the brake system line test generally adopts a centralized test system. However, due to the harsh test environment of rail vehicles, susceptibility to electromagnetic interference, the large number of test points and their scattered locations, and the long distance between the sensor installation location and the main test device, there are the following problems:

[0004] 1. A large number of cables are used as transmission media for data transmission. The test system connection is complicated, and the cable installation, wiring, and removal are time-consuming and labor-intensive. During the installation test, there is a high risk of falling off, breaking, short circuiting, or wrong connection, which is difficult to troubleshoot and poses a major electrical and mechanical safety hazard.

[0005] 2. When transmitting various types of analog signals, especially voltage signals, over long distances, cables are susceptible to electromagnetic interference from the on-site environment, which reduces measurement accuracy.

[0006] 3. Centralized test systems usually integrate all sensor acquisition equipment and computing hosts. The central test equipment needs to complete sensor signal acquisition, processing, transmission and calculation, which has high performance requirements for the central test equipment and high test costs. The central test equipment of different companies is relatively closed and cannot be compatible and expanded. The feasibility of customization for brake system signal acquisition is not high.

[0007] 4. The test process and test data cannot be transmitted synchronously, R&D and testing cannot be shared in real time, and vehicle, traction, network and other systems cannot be shared in real time with braking tests. There is a lag, which reduces test efficiency.

[0008] 5. Test data analysis and calculation issues. At present, there is no unified standard for braking distance correction at home and abroad. There is a simple definition and description of the longitudinal impact rate, but there is a lack of further detailed quantitative formula description. There is currently no evaluation method and index for the smoothness of electric-pneumatic conversion.

[0009] In general, with the continuous development of rail vehicle braking systems, limited transmission and centralized testing systems can no longer meet the requirements in terms of testing efficiency, testing accuracy, system real-time and reliability. Summary of the invention

[0010] In view of the technical problems of low efficiency, accuracy, real-time performance and reliability of the above-mentioned existing test systems, the present invention proposes a distributed test system and method for a brake system based on wireless transmission.

[0011] In a first aspect, an embodiment of the present application provides a distributed testing system for a braking system based on wireless transmission, comprising:

[0012] An intelligent detection terminal is used to collect test data and send the collected test data to a wireless intelligent gateway via wireless transmission;

[0013] A wireless intelligent gateway, used for receiving the test data sent by the intelligent detection terminal, and sending the test data to a database via 5G communication;

[0014] The host computer is provided with host computer software, and the host computer software is used for remote access, test configuration, real-time monitoring, and automatic analysis and processing of the test data in the database.

[0015] In the above-mentioned distributed testing system, the intelligent detection terminal includes a sensing module, a collection module, a wireless transmission module, and a power supply module for providing redundant power supply and low voltage warning to the sensing module, the collection module, and the wireless transmission module.

[0016] The above-mentioned distributed testing system, wherein the intelligent detection terminal includes a hard-wired instruction intelligent detection terminal for collecting control instructions, an air circuit pressure intelligent detection terminal for collecting brake cylinder pressure, a braking force intelligent detection terminal for collecting brake shoe / brake pad braking force, an acceleration intelligent detection terminal for collecting motor vehicle and trailer acceleration, a radar intelligent detection terminal for collecting train speed and running distance, a brake system maintenance terminal wireless terminal for collecting brake system internal communication bus data, a thermocouple intelligent detection terminal for collecting brake shoe / brake pad temperature, and a GPS intelligent detection terminal for collecting train position.

[0017] The above-mentioned distributed test system, wherein the host computer software includes a presentation layer, a logic analysis layer and a data service layer; the logic analysis layer is used to automatically process and analyze the test data through the braking system performance model, and transmit the analysis results to the presentation layer; the data service layer is used to provide resource access support to the logic analysis layer through the database management system, and receive the operation requirements for the test data in the database issued by the logic analysis layer.

[0018] In the above-mentioned distributed test system, the logic analysis layer determines the braking system performance by performing braking distance correction, longitudinal impact rate calculation and electric-air conversion smoothness evaluation based on the test data through the braking system performance model.

[0019] The above-mentioned distributed testing system, wherein the braking system performance model comprises:

[0020] The braking distance correction unit is used to obtain the corrected braking distance of the test vehicle according to the actual braking distance of the test vehicle, the target initial speed, the actual initial braking speed, the idling time, the total mass of the test vehicle, the static mass of the test vehicle, the line slope and the average curve resistance of the track in the test data.

[0021] The above-mentioned distributed testing system, wherein the braking system performance model further includes:

[0022] An acceleration segmentation unit, used for dividing the acceleration signal in the test data into a high-speed stage, a low-speed stage and a parking stage according to the initial speed when the braking command is applied, the electric-air conversion point speed and the electric brake complete exit speed;

[0023] The longitudinal impact rate acquisition unit obtains the longitudinal impact rate according to the acceleration change rate in the high-speed stage and the low-speed stage; in the parking stage, the acceleration data of the parking stage is segmented according to the speed level and the longitudinal impact rate is obtained by using the maximum value of the self-power spectrum density method.

[0024] The above-mentioned distributed testing system, wherein the braking system performance model further includes:

[0025] The electric-to-air conversion smoothness evaluation unit is used to evaluate the electric-to-air conversion smoothness of the test vehicle in the low-speed stage according to the average deceleration of the test vehicle in the high-speed stage when the acceleration is stable and the average deceleration in different speed levels in the low-speed stage.

[0026] In a second aspect, an embodiment of the present application provides a distributed testing method for a braking system based on wireless transmission, which is applied to the distributed testing system described in the first aspect, including:

[0027] Data collection step: collecting test data through the intelligent detection terminal, and sending the collected test data to the wireless intelligent gateway through wireless transmission;

[0028] Data storage step: collecting the test data through the wireless intelligent gateway, storing it through a storage medium, and sending the test data to a database through 5G communication;

[0029] Data processing steps: remote access, test configuration, real-time monitoring, and automatic analysis and processing of the test data are performed through the host computer software.

[0030] In the above-mentioned distributed testing method, the data processing step includes:

[0031] Data filtering step: performing low-pass filtering on the analog signal test data in the test data;

[0032] Performance determination steps: The braking system performance is determined by using a braking system performance model to perform braking distance correction, longitudinal impact rate calculation, and electric-pneumatic conversion smoothness evaluation on the filtered test data.

[0033] Compared with the prior art, the advantages and positive effects of the present invention are:

[0034] 1. Apply WIFI-based wireless sensor network technology to the rail vehicle test system, reduce the use of a large number of cables through wireless data transmission, reduce the requirements for the on-site environment, reduce the installation cost of test equipment, and reduce safety hazards.

[0035] 2. Adopt a distributed system, support open protocols, and be compatible with third-party device expansion.

[0036] 3. Through synchronous data uploading and real-time sharing, different platforms can remotely monitor test data and conduct full system analysis of problems found in the test.

[0037] 4. Automatically analyze the performance of the braking system based on the braking system performance model. For the correction of braking distance, consider the combined effects of multiple factors such as initial velocity error, response time, line slope, line curve, etc. The longitudinal impact rate fully considers the key factors of different speed stages, and proposes a calculation method combining the acceleration change rate and the maximum value method of the self-power spectrum density periodogram; and for the first time, proposes an evaluation index for the smoothness of electric-pneumatic conversion.

[0038] 5. Good maintainability. The test system adopts a host-server architecture. The host computer adopts division of labor and service. The functions are independent of each other. Only related logical components and performance models need to be modified between different vehicles and different projects. No changes are needed to the hardware and software architecture, thereby reducing the maintenance cost of the test system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 A framework diagram of a distributed testing system for a braking system provided by the present invention;

[0040] Figure 2 A general hardware structure diagram of the intelligent detection terminal provided by the present invention;

[0041] Figure 3A diagram of the distributed topology architecture of the intelligent detection terminal provided by the present invention;

[0042] Figure 4 This is an architecture diagram of an embodiment of a brake system distributed testing system based on wireless transmission provided by the present invention;

[0043] Figure 5 A schematic diagram of the steps of a distributed testing method for a brake system provided by the present invention. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. Based on the embodiments provided in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0045] Obviously, the drawings described below are only some examples or embodiments of the present application. For ordinary technicians in this field, the present application can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed in this application, some changes in design, manufacturing or production based on the technical content disclosed in this application are just conventional technical means, and should not be understood as insufficient content disclosed in this application.

[0046] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those of ordinary skill in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0047] Unless otherwise defined, the technical terms or scientific terms involved in this application should be understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the" and the like involved in this application do not indicate a quantitative limitation, and may represent the singular or plural. The terms "include", "comprise", "have" and any of their variations involved in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there may be three relationships, for example, "A and / or B" can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0048] The present invention is described in detail below in conjunction with the various embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not limitations of the present invention, and any equivalent transformations or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these embodiments are all within the scope of protection of the present invention.

[0049] Embodiment 1:

[0050] Figure 1 A framework diagram of a distributed testing system for a braking system based on wireless transmission provided by the present invention, such as Figure 1 As shown, this embodiment discloses a specific implementation of a distributed testing system for a braking system based on wireless transmission (hereinafter referred to as “system”).

[0051] Specifically, the system disclosed in this embodiment mainly includes: an intelligent detection terminal, a wireless intelligent gateway, a server and a host computer;

[0052] An intelligent detection terminal is used to collect test data and send the collected test data to a wireless intelligent gateway via wireless transmission;

[0053] The intelligent detection terminal includes a hard-wired command intelligent detection terminal for collecting control commands, an air circuit pressure intelligent detection terminal for collecting brake cylinder pressure, a braking force intelligent detection terminal for collecting brake shoe / brake pad braking force, an acceleration intelligent detection terminal for collecting motor vehicle and trailer acceleration, a radar intelligent detection terminal for collecting train speed and running distance, a brake system maintenance terminal wireless terminal for collecting brake system internal communication bus data, a thermocouple intelligent detection terminal for collecting brake shoe / brake pad temperature, and a GPS intelligent detection terminal for collecting train position;

[0054] Further, such as Figure 2 As shown, all intelligent detection terminals include a perception module, an acquisition module, a wireless transmission module, and a power supply module for redundant power supply and low voltage warning for the perception module, acquisition module, and wireless transmission module. Among them, the perception module adopts a multiplexing structure and may include multiple sensors of the same type; the acquisition module includes a signal processing circuit, a multiplexer, a programmable gain amplifier, an analog-to-digital or digital-to-digital conversion circuit, a central processing unit, and a serial port part; the wireless transmission module adopts a wireless WIFI module; the power supply module mainly includes a rechargeable energy storage element, a battery, and a voltage switching, conversion, and low voltage warning circuit, which can provide redundant power supply and low voltage warning for the perception module, acquisition module, and wireless transmission module. The test system can switch the acquisition detection terminal sensor channel according to the multiplexer, and can configure the number of detection terminals according to the test requirements.

[0055] This application applies WIFI-based wireless sensor network technology to the rail vehicle test system, uses wireless sensor networks instead of cable media for data transmission, and has wireless synchronous transmission technology for various types of sensors; wireless data transmission can reduce the use of a large number of cables, reduce the requirements for the on-site environment, reduce the installation cost of test equipment, and reduce safety hazards.

[0056] The test system further includes: a wireless intelligent gateway, configured to receive the test data sent by the intelligent detection terminal, and send the test data to a database via 5G communication;

[0057] Intelligent detection terminals and wireless intelligent gateways form a wireless sensor network. The wireless sensor network supports open protocols and has the characteristics of self-organizing networking, easy expansion, and compatibility with third-party devices.

[0058] Specifically, Figure 3 As shown,

[0059] After the hard-wired instruction intelligent detection terminal collects the control instruction, it sends it to the wireless intelligent gateway through the wireless WIFI module. The hard-wired instruction intelligent detection terminal includes an embedded digital collection and transmission module.

[0060] The air circuit pressure intelligent detection terminal collects the brake cylinder pressure and sends it to the wireless intelligent gateway through the wireless WIFI module. The air circuit pressure intelligent detection terminal includes a pressure sensor module and an embedded analog quantity acquisition and transmission module.

[0061] The intelligent braking force detection terminal collects the braking force of the brake shoe / brake pad and sends it to the wireless intelligent gateway through the wireless WIFI module. The intelligent braking force detection terminal includes a braking force sensor and an embedded analog quantity acquisition and transmission module.

[0062] The acceleration intelligent detection terminal collects the acceleration of the motor vehicle and the trailer and sends it to the wireless intelligent gateway through the wireless WIFI module. The acceleration intelligent detection terminal includes an acceleration sensor and an embedded analog quantity acquisition and transmission module.

[0063] After the radar intelligent detection terminal collects the train speed and running distance, it sends them to the wireless intelligent gateway through the wireless WIFI module. The radar intelligent detection terminal includes a Doppler radar and an embedded acquisition and transmission module.

[0064] The brake system maintenance terminal wireless terminal collects all the data of the brake system internal communication bus, and sends it to the wireless intelligent gateway through the wireless WIFI module after protocol conversion. The brake system maintenance terminal wireless terminal includes an embedded communication device.

[0065] After the thermocouple intelligent detection terminal collects the brake shoe / brake plate temperature, it sends it to the wireless intelligent gateway through the wireless WIFI module. The thermocouple intelligent detection terminal includes a thermocouple and an embedded analog quantity acquisition and transmission module.

[0066] After the GPS intelligent detection terminal collects the train position, it sends it to the wireless intelligent gateway through the wireless WIFI module. The GPS intelligent detection terminal includes a GPS module and an embedded communication module.

[0067] In the above embodiments, the present application adopts a distributed topology architecture, adopts a distributed intelligent detection terminal to collect brake system test data, and replaces the traditional centralized test system. The architecture supports open protocols, is compatible with third-party equipment, and is scalable.

[0068] like Figure 4 As shown in the figure, after the wireless intelligent gateway module collects all the data from the intelligent detection terminals, the data is stored through the storage medium, which includes TF card, SD card, CF card, etc. At the same time, it is sent to the equipment of the on-site test personnel through the wireless WIFI module, such as Figure 4 The on-site monitoring terminal in the network sends the data to the database through 5G communication via the public network. It should be noted that the wireless intelligent gateway has the function of breakpoint resumption. On lines with weak 5G signals, the data can be cached first and sent again after the signal is restored.

[0069] Therefore, the above embodiment can realize real-time sharing through synchronous data uploading, so that different platforms can remotely monitor test data and conduct full system analysis on problems found in the test.

[0070] The above test system also includes a server, which uses a self-built public network server to receive and store line test data (i.e. test data collected by the intelligent detection terminal) in real time for real-time access and query by authorized personnel. The data transmission path can be referred to Figure 4 .

[0071] The above-mentioned test system also includes a host computer, which is provided with host computer software, and the host computer software is used for remote access, test configuration, real-time monitoring, and automatic analysis and processing of the test data in the database.

[0072] Specifically, the host computer software is divided into three layers, including a presentation layer, a logic analysis layer and a data service layer; it has at least four functions: remote access, test configuration, real-time monitoring and automatic data processing and analysis.

[0073] The presentation layer includes the user interaction interface between the user and the test system, and is responsible for test configuration and real-time monitoring of test analysis data. Considering the need for simultaneous monitoring and analysis of data for vehicles, traction, network and braking systems, the presentation layer adopts a C / S and B / S architecture. The C / S (client / server) method is used for test system configuration and operation at the test site, and the B / S (browser / server) method is used for browsing and querying at non-test sites, meeting the needs of all parties involved in the test and achieving real-time sharing of multiple systems and multiple scenarios.

[0074] The logic analysis layer is used to automatically process and analyze the test data through the braking system performance model, and transmit the analysis results to the presentation layer; the data service layer is used to provide resource access support to the logic analysis layer through the database management system, and receive the operation requirements for the test data in the database issued by the logic analysis layer.

[0075] Specifically, the logic analysis layer can realize automatic processing and analysis of test data, including data filtering, numerical calculation, performance modeling and performance judgment, and pass the analysis results to the presentation layer. According to the characteristics of rail vehicle signals, the analog signal test data is low-pass filtered using the Butterworth filter method, and the filter parameters are set according to the sensor and test requirements. For the filtered data, the braking response time, corrected braking distance, average braking deceleration, longitudinal impact rate, thermal capacity and other items are automatically calculated in accordance with GB / T 14894-2005 "Inspection and Test Rules for Urban Rail Transit Vehicles after Assembly" and IEC_61133-2006 "Vehicle Test Specifications before Vehicle Assembly and Operation". Finally, according to the established braking system performance model, all valid test analysis data are statistically analyzed to determine the braking system performance and predict the system failure risk.

[0076] Furthermore, the logic analysis layer determines the braking system performance by performing braking distance correction, longitudinal impact rate calculation and electric-air conversion smoothness evaluation based on the test data through the braking system performance model;

[0077] In the above embodiment, the braking system performance model includes:

[0078] A braking distance correction unit is used to obtain a corrected braking distance of the test vehicle according to the actual braking distance of the test vehicle, the target initial speed, the actual initial braking speed, the idling time, the total mass of the test vehicle, the static mass of the test vehicle, the line slope and the average curve resistance of the track in the test data;

[0079] Specifically, the braking distance correction using the collected test data in the braking system performance model is calculated using the following formula, taking into account the initial velocity error, response time, line slope, line curve and other factors:

[0080]

[0081] Among them, Ls is the corrected braking distance; L1 is the measured actual braking distance; υ2 is the target initial speed; υ1 is the actual braking initial speed; t0 is the idling time; M is the total mass of the vehicle under test, including static mass and rotational mass, in tons; m is the static mass of the vehicle under test, in tons; ρ = M / m, if there is no regulation, it is taken as 1.08; i is the slope of the line, positive for uphill and negative for downhill, in mm / m; W B0 is the average curve resistance of the track. For curves with a radius of 1000 to 5000 m, When the curve radius is greater than 5000m, the curve resistance can be ignored.

[0082] In the above formula, ρ=M / m, which refers to standards such as GB / T 14894-2005 "Rules for Inspection and Testing of Urban Rail Transit Vehicles after Assembly" and IEC_61133-2006 "Specifications for Vehicle Testing before Assembly and Operation".

[0083] On the other hand, the braking system performance model also includes:

[0084] An acceleration segmentation unit, used for dividing the acceleration signal in the test data into a high-speed stage, a low-speed stage and a parking stage according to the initial speed when the braking command is applied, the electric-air conversion point speed and the electric brake complete exit speed;

[0085] The longitudinal impact rate acquisition unit obtains the longitudinal impact rate according to the acceleration change rate in the high-speed stage and the low-speed stage; in the parking stage, the acceleration data of the parking stage is segmented according to the speed level and the longitudinal impact rate is obtained by using the maximum value of the self-power spectrum density method.

[0086] The electric-to-air conversion smoothness evaluation unit is used to evaluate the electric-to-air conversion smoothness of the test vehicle in the low-speed stage according to the average deceleration of the test vehicle in the high-speed stage when the acceleration is stable and the average deceleration in different speed levels in the low-speed stage.

[0087] Among them, the longitudinal impact rate is usually obtained by ζ = △a / △t, but the different values ​​of △t lead to large fluctuations in the longitudinal impact rate curve, and this formula cannot reflect the huge impulse caused by the change of the basic brake dynamic friction coefficient and the air spring structure when the train is about to stop. In addition, the smoothness of the electric-pneumatic conversion is reflected by the acceleration curve.

[0088] The braking system energy model aims at the electric-pneumatic conversion smoothness and longitudinal impact rate, considers the key influencing factors in different speed stages, and proposes an acceleration signal analysis method based on sub-speed sections according to the speed and acceleration signals collected in real time.

[0089] Firstly, the acceleration signal is divided into a high-speed stage (from the initial speed when the braking command is applied to the electric-to-air conversion point speed), a low-speed stage (from the electric-to-air conversion point speed to the electric brake complete exit speed point) and a parking stage (from the electric brake complete exit speed point to the train complete stationary state) according to different speeds.

[0090] In the high-speed and low-speed stages, the key factor affecting the longitudinal impact rate is the change in brake cylinder pressure, which is calculated using the acceleration change rate, that is, ζ = △a / △t, where △t is the time it takes for the braking force to rise from 10% to 90%. In the parking stage, the key factors affecting the longitudinal impact rate are the change in the friction coefficient of the basic brake unit, the wheel-rail relationship, the structure of the air spring itself, etc., which are calculated using the maximum power spectrum density method. The acceleration data in the parking stage is segmented again according to the speed level (it is recommended to be graded at 0.5Km / h), and each segment of the data is discrete Fourier transformed. The formula is as follows:

[0091]

[0092] Among them, A(k) is the corresponding modulus value under different frequency components; N is the length of the sampling sequence in the data segment; a(n) is the acceleration sampling value in the data segment.

[0093] Next, take the sum of the squares of the modulus values ​​and divide it by the length of the sampling sequence to get the estimated value of the power spectrum density. The formula is as follows:

[0094]

[0095] Among them, S a is the power spectral density estimate; W k is the frequency weight coefficient; N is the length of the sampling sequence in the data segment.

[0096] Finally, the maximum value of the power spectrum density of all speed segment data is taken as the comfort evaluation index of the parking stage. That is:

[0097]

[0098] in, It is the comfort index of the braking and stopping stage. Here, the comfort index of the braking and stopping stage can be divided into five levels (comfortable, relatively comfortable, general, relatively uncomfortable, and uncomfortable) for evaluation.

[0099] On the other hand, in this embodiment, the smoothness of the electric-air conversion is evaluated at the low speed stage. Smoothness involves the conversion of air braking force and electric braking force. The smoothness of this force conversion can only be reflected by the smoothness of the acceleration curve. Variance statistics are used. First, the average deceleration value when the acceleration is stable at the high speed stage is calculated. Then find the sampling sequence pair in the low-speed stage The variance of . That is:

[0100]

[0101] Among them, P is the smoothness calculation index; N is the number of speed levels in the low-speed stage. If there is no regulation, it is recommended to use 0.5 km / h for gradient grading; a iis the average deceleration within the corresponding speed level; It is the average deceleration value when the acceleration is stable in the high-speed stage.

[0102] Here, P can be divided into five levels (smooth, relatively smooth, average, relatively rough, and rough) for evaluation.

[0103] In the above embodiments, the present application automatically analyzes the performance of the braking system based on the braking system performance model. The braking distance correction takes into account the combined effects of multiple factors such as initial velocity error, response time, line ramp, and line curve. The longitudinal impact rate fully considers the key factors of different speed stages, and proposes a calculation method that combines the acceleration change rate and the maximum value method of the self-power spectrum density periodogram. And for the first time, an evaluation index for the smoothness of electric-pneumatic conversion is proposed.

[0104] In addition, the test system proposed in this application also has the advantage of good maintainability. The test system adopts a host-server architecture. The host computer adopts division of labor and service. The functions are independent of each other. Only related logical components and performance models need to be modified between different vehicles and different projects. There is no need to make any changes to the hardware and software architecture, thereby reducing the maintenance cost of the test system.

[0105] Embodiment 2:

[0106] In combination with a distributed testing system for a braking system based on wireless transmission disclosed in Embodiment 1, this embodiment discloses a specific implementation example of a distributed testing method for a braking system based on wireless transmission (hereinafter referred to as “method”).

[0107] Reference Figure 5 As shown, the method includes:

[0108] Step S1: collecting test data through the intelligent detection terminal, and sending the collected test data to the wireless intelligent gateway through wireless transmission;

[0109] Step S2: collecting the test data through the wireless intelligent gateway, storing the test data through a storage medium, and sending the test data to a database through 5G communication;

[0110] Step S3: remotely access, test configuration, real-time monitoring, and automatic analysis and processing of the test data through the host computer software.

[0111] Specifically, step S3 includes the following contents:

[0112] Step S31: performing low-pass filtering on the analog signal test data in the test data;

[0113] Step S32: The brake system performance is determined by using a brake system performance model to perform braking distance correction, longitudinal impact rate calculation, and electro-pneumatic conversion smoothness evaluation on the filtered test data.

[0114] Further, step S32 includes:

[0115] Step S321, obtaining a corrected braking distance of the test vehicle according to the actual braking distance of the test vehicle, the target initial speed, the actual initial braking speed, the idling time, the total mass of the test vehicle, the static mass of the test vehicle, the line slope and the average curve resistance of the track in the test data.

[0116] Step S322, dividing the acceleration signal in the test data into a high-speed stage, a low-speed stage and a parking stage according to the initial speed when the braking command is applied, the electric-air conversion point speed and the electric brake complete exit speed;

[0117] Step S323, in the high-speed stage and the low-speed stage, the longitudinal impact rate is obtained according to the acceleration change rate; in the parking stage, the acceleration data of the parking stage is segmented according to the speed level and the longitudinal impact rate is obtained by the maximum power spectrum density method.

[0118] Step S324, evaluating the electric-air conversion smoothness of the test vehicle in the low-speed stage according to the average deceleration of the test vehicle in the high-speed stage with stable acceleration and the average deceleration in different speed levels in the low-speed stage.

[0119] The technical solutions of the distributed testing method for a braking system based on wireless transmission disclosed in this embodiment and the distributed testing system for a braking system based on wireless transmission disclosed in Embodiment 1 are the same as those of the other parts. Please refer to Embodiment 1 and no further details will be given here.

[0120] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0121] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A distributed testing system for a brake system, characterized in that: Based on wireless transmission, including: An intelligent detection terminal is used to collect test data and send the collected test data to a wireless intelligent gateway via wireless transmission; A wireless intelligent gateway, used for receiving the test data sent by the intelligent detection terminal, and sending the test data to a database via 5G communication; A host computer, wherein the host computer is provided with host computer software, and the host computer software is used for remote access, test configuration, real-time monitoring, and automatic analysis and processing of the test data in the database; The upper computer software includes a presentation layer, a logic analysis layer and a data service layer; the logic analysis layer is used to automatically process and analyze the test data through the brake system performance model, and transmit the analysis results to the presentation layer; the data service layer is used to provide resource access support to the logic analysis layer through the database management system, and receive the operation requirements for the test data in the database issued by the logic analysis layer; The logic analysis layer determines the braking system performance by performing braking distance correction, longitudinal impact rate calculation and electric-air conversion smoothness evaluation based on the test data through the braking system performance model; The braking system performance model includes: A braking distance correction unit is used to obtain a corrected braking distance of the test vehicle according to the actual braking distance of the test vehicle, the target initial speed, the actual initial braking speed, the idling time, the total mass of the test vehicle, the static mass of the test vehicle, the line slope and the average curve resistance of the track in the test data; Specifically, the braking distance correction expression is as follows: Among them, Ls is the corrected braking distance; L1 is the measured actual braking distance; υ2 is the target initial speed; υ1 is the actual braking initial speed; t0 is the idling time; M is the total mass of the vehicle under test, including static mass and rotational mass, in tons; m is the static mass of the vehicle under test, in tons; ρ = M / m, if there is no regulation, it is taken as 1.08; i is the slope of the line, positive for uphill and negative for downhill, in mm / m; W B0 is the average curve resistance of the track. For curves with a radius of 1000 to 5000 m, When the curve radius is greater than 5000m, the curve resistance is negligible; An acceleration segmentation unit, used for dividing the acceleration signal in the test data into a high-speed stage, a low-speed stage and a parking stage according to the initial speed when the braking command is applied, the electric-air conversion point speed and the electric brake complete exit speed; The longitudinal impact rate acquisition unit obtains the longitudinal impact rate according to the acceleration change rate in the high-speed stage and the low-speed stage; in the parking stage, the acceleration data of the parking stage is segmented according to the speed level and the longitudinal impact rate is obtained by using the maximum value of the self-power spectrum density method; An electric-to-air conversion smoothness evaluation unit is used to evaluate the electric-to-air conversion smoothness of the test vehicle at a low speed stage according to the average deceleration of the test vehicle at a high speed stage with stable acceleration and the average deceleration within different speed levels at a low speed stage; Specifically, in the low-speed stage, the electric-air conversion smoothness evaluation index is obtained by calculating the average deceleration variance of the low-speed stage relative to the average deceleration variance when the acceleration is stable in the high-speed stage.

2. The distributed test system according to claim 1, characterized in that: The intelligent detection terminal includes a sensing module, a collection module, a wireless transmission module, and a power supply module for providing redundant power supply and low voltage warning to the sensing module, the collection module, and the wireless transmission module.

3. The distributed testing system according to claim 1, characterized in that: The intelligent detection terminal includes a hard-wired instruction intelligent detection terminal for collecting control instructions, an air circuit pressure intelligent detection terminal for collecting brake cylinder pressure, a braking force intelligent detection terminal for collecting brake shoe / brake pad braking force, an acceleration intelligent detection terminal for collecting motor vehicle and trailer acceleration, a radar intelligent detection terminal for collecting train speed and running distance, a brake system maintenance terminal wireless terminal for collecting brake system internal communication bus data, a thermocouple intelligent detection terminal for collecting brake shoe / brake pad temperature, and a GPS intelligent detection terminal for collecting train position.

4. A distributed testing method for a brake system, applied to the distributed testing system according to any one of claims 1 to 3, characterized in that: include: Data collection step: collecting test data through the intelligent detection terminal, and sending the collected test data to the wireless intelligent gateway through wireless transmission; Data storage step: collecting the test data through the wireless intelligent gateway, storing it through a storage medium, and sending the test data to a database through 5G communication; Data processing steps: remote access, test configuration, real-time monitoring, and automatic analysis and processing of the test data are performed through the host computer software.

5. The distributed testing method according to claim 4, characterized in that: The data processing steps include: Data filtering step: performing low-pass filtering on the analog signal test data in the test data; Performance determination steps: The braking system performance is determined by using a braking system performance model to perform braking distance correction, longitudinal impact rate calculation, and electric-pneumatic conversion smoothness evaluation on the filtered test data.

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