Radio frequency power supply railway monitoring system and use method thereof

Abstract

The invention provides a maintenance-free automatic track monitoring system which is used for monitoring a track and detecting potential risks possibly causing potential safety hazards or derailing. The track monitoring system can operate normally during railway service, and train operation does not need to be interrupted. A track monitoring system includes a vehicle-mounted device and a roadside battery-less sensing tag (WBST). The in-vehicle device wirelessly charges the WBST with radio frequency (RF) energy. When a train passes, the WBST can collect data of rail vibration, temperature and the like and then transmit the data back to the vehicle-mounted equipment. The provided track monitoring system can find danger as soon as possible and provide valuable data for further analysis and real-time alarm, so that the railway safety and maintenance efficiency are improved.

Description

Technical Field

[0001] The present invention relates to the technical fields of railway monitoring and radio frequency energy harvesting. More particularly, the present invention relates to a battery-free radio frequency powered system for real-time track condition monitoring. Background Art

[0002] Since the First Industrial Revolution, the global railway network has expanded dramatically due to the massive growth in trade and population. Maintaining this vastly expanded railway network presents significant challenges in terms of timeliness, cost, and efficiency. Currently, track inspections are primarily performed by specialized track inspection vehicles, which can measure various track parameters. However, these vehicles require extended track occupancy, reducing operational efficiency and increasing costs.

[0003] To prevent accidents, artificial intelligence (AI) predictive models based on machine learning and reinforcement learning have been proposed. However, because these models require large amounts of measurement data, they cannot replace real-time monitoring results. Wireless sensor nodes combined with the Internet of Things (IoT) offer a solution for large-scale infrastructure monitoring. However, existing self-powered sensors have a narrow operating bandwidth, making it difficult to design a system that works under all operating conditions. Wireless power transmission methods, such as inductive and magnetic coupling, are widely used in short-range applications such as charging electronic devices, but are not suitable for high-speed trains.

[0004] One of the related documents discloses an onboard monitoring system for monitoring tracks, detecting hazards, and issuing warnings regarding train operations that could lead to various safety issues or even derailments. This monitoring system can be installed on passenger or freight trains. An imaging module on the vehicle captures video images of the track as the train moves. These images are automatically processed by an onboard computer to determine whether there are any irregularities on the track. However, this approach limits the maximum speed of trains and reduces the efficiency of the railway system.

[0005] One related document discloses a sensing method that utilizes sensors and wireless data transmission to monitor train components, such as bogies. The sensors can record changes in the same target component over time, helping to identify component failures, their status, and predict failure times. However, this method only monitors the train's status and cannot replace manual track inspections.

[0006] A related report, “Health Monitoring of Urban Rail Corrugations Using Wirelessly Charged Sensor Nodes,” introduces a system for urban rail corrugation health monitoring using wirelessly charged sensor nodes. The proposed system includes a local energy generator based on the principle of electromagnetic induction. In addition, a vehicle-track model is established to study the dynamic response of railway tracks with and without track corrugations. The nonlinear wheel-rail contact force based on Hertzian elastic contact theory, combined with a fast explicit time integration method, can be used to calculate the dynamic response of the vehicle-track coupled system. However, the sensor nodes used only operate in a resonant state, which means that maximum energy harvesting is only possible under specific conditions. In addition, the sensor nodes are large in size, which also restricts the installation conditions.

[0007] Another related report, “Self-powered Wireless Smart Sensor for Train Monitoring System Based on Magnetic Levitation Porous Nanogenerator,” demonstrates a self-powered wireless smart sensor that can be powered by train-induced vibration energy through a magnetic levitation porous nanogenerator (MPNG). The integrated MPNG includes a triboelectric nanogenerator (TENG), which can provide a peak power density of 0.34mW / g at 50MΩ, and an electromagnetic generator (EMG), which can provide a peak power density of 0.12mW / g at 700Ω. However, the sensor used in this study still faces the limitation of having to operate under a single working condition. In addition, the sensing system focuses on bogie health monitoring rather than monitoring the condition of the railway track.

[0008] Another related report, "High-Power, Rugged Piezoelectric Energy Harvester for Wireless Sensor Networks in Railway Applications," demonstrates a piezoelectric stack energy harvester for railway track monitoring. Under 21Hz, 0.7g RMS (root mean square) harmonic excitation, it achieved a maximum power of 511mW and an average power of 24.5mW. Under measured railway track vibration signals, it achieved a maximum power of 568mW and an average power of 7.3mW. However, the manufacturing process for piezoelectric stack components is complex and costly, making them unsuitable for railway monitoring systems requiring a large number of sensor nodes.

[0009] Another related report, "Advanced Monitoring System for Battery-Free Asset Tracking Modules Powered by RF Wireless Power Transfer," demonstrates a system that uses RF wireless power transfer (WPT) to power battery-free Bluetooth Low Energy (BLE) tags for object tracking. Powered by RF energy, these battery-free tags can identify and monitor object speed. However, this system's low energy transfer efficiency makes it unsuitable for high-speed trains.

[0010] Therefore, there is a need for a battery-free and RF-powered railway monitoring system that can monitor track conditions in real time and reduce maintenance costs. Summary of the Invention

[0011] Based on the above, the purpose of the present invention is to provide a system and method to solve the shortcomings and unmet needs mentioned in the prior art.

[0012] In the present invention, a radio frequency powered (RF-powered) railway monitoring system is proposed. The railway monitoring system combines wayside battery-free sensing tags (WBST) to address the limitations of existing railway monitoring systems. The developed passive wireless sensor can obtain energy from the RF power supply on the train to measure track acceleration and temperature in real time without replacing batteries and improve railway safety. Unlike traditional monitoring systems, the use of WBST can achieve battery-free operation, compact size, minimal impact on train operation, stable energy transmission and real-time data collection. The detection system can be optimized according to the conditions of use and applied to other wireless monitoring scenarios. Therefore, the proposed RF-powered railway monitoring system has outstanding performance in maintenance-free operation, high energy transmission efficiency and real-time monitoring.

[0013] According to one aspect of the present invention, a battery-free, RF-powered railway monitoring system is provided. The railway monitoring system includes multiple onboard energy generators, multiple WBSTs, at least one onboard reader, a base station, a server, and a control center. The onboard energy generator is mounted on a train. The WBSTs are fixedly mounted on tracks along a train route, where the train travels along the tracks according to a predetermined route. The onboard energy generator is configured to wirelessly transmit RF energy to the WBSTs for power when the train passes. This eliminates the need for batteries and allows the WBSTs to be powered solely by the RF energy provided by the onboard energy generator. The WBSTs are configured to collect track parameters of the tracks along the train route, continuously monitoring one or more track parameters as the train passes. An onboard reader is mounted on the train and receives data transmitted from the WBSTs to obtain track conditions beneath the moving train. The onboard reader processes the data and determines whether the track conditions meet predefined safety thresholds, thereby assessing whether any track or track section is damaged. If an anomaly is detected, the onboard reader is activated and emits a signal or data. The base station serves as an intermediate communication hub, receiving track data from onboard readers. The server stores and organizes track data from the base station for long-term analysis and railway condition monitoring. The control center retrieves data from the server and performs real-time analysis of the railway's track conditions. If an anomaly is detected, the control center triggers an alarm and notifies external systems.

[0014] Through the above configuration, the present invention provides at least three creative technical effects, which are summarized as follows:

[0015] (1) RF-powered railway monitoring systems offer excellent maintenance efficiency. Using WBST, they contain no batteries, require no cabling, and require no manual maintenance throughout the component's lifecycle.

[0016] (2) RF-powered railway monitoring systems can collect a large amount of real-time data about the tracks as trains pass by. The collected data can enable accurate and timely risk assessments. In addition, by analyzing data trends, the system can estimate the service life of the tracks and optimize maintenance plans accordingly.

[0017] (3) The RF-powered railway monitoring system is highly scalable and can be applied to other infrastructure monitoring applications. The system’s circuit design and sensor configuration can also be optimized to meet the specific needs of different monitoring scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The embodiments of the present invention are described in more detail below with reference to the accompanying drawings, in which:

[0019] Figure 1A schematic diagram of a sensing technology solution for a railway monitoring system without batteries and powered by radio frequency is shown according to an embodiment of the present invention;

[0020] Figure 2 A schematic diagram showing an architecture of a vehicle-mounted reader connected to and interacting with other components according to an embodiment of the present invention;

[0021] Figure 3 A schematic block diagram showing how electrical energy is transferred to accomplish communication according to an embodiment of the present invention;

[0022] Figure 4A A schematic diagram of the system architecture of a roadside battery-free sensing tag (WBST) is shown according to an embodiment of the present invention;

[0023] Figure 4B The present invention shows various modules connected by pin connectors, and details the embedded system, power management unit (PMU), energy harvesting (EH) circuit and communication antenna.

[0024] Figure 4C The measured power consumption graph of WBMT is shown;

[0025] Figure 5A 、 Figure 5B and Figure 5C A schematic diagram showing a design of a miniature branch line coupler (mini-BLC) according to an embodiment of the present invention;

[0026] Figure 6A 、 Figure 6B and Figure 6C A performance comparison chart showing the conventional mini-BLC and the proposed mini-BLC; and

[0027] Figure 7A 、 Figure 7B 、 Figure 7C and Figure 7D A comparison diagram between the proposed energy harvesting scheme and the traditional scheme is shown. DETAILED DESCRIPTION

[0028] In the following description, a radio frequency powered (RF powered) railway monitoring system and the like will be described as a preferred example. Those skilled in the art will appreciate that modifications, including additions and / or substitutions, may be made without departing from the scope and spirit of the present invention. Specific details may be omitted so as not to obscure the present invention; however, this disclosure is written to enable those skilled in the art to practice the teachings herein without undue experimentation.

[0029] The present invention provides a railway monitoring system, which is characterized by adopting a battery-free and radio frequency powered railway monitoring method. The proposed railway monitoring system can utilize radio frequency wireless power transmission to enhance the safety of the railway system.

[0030] Generally speaking, a battery-free, RF-powered railway monitoring system consists of an on-board energy generator, an on-board reader, and a wayside battery-free sensing tag (WBST). In this article, "on-board" means that the components are attached to the train (on-train); for example, an on-board energy generator and an on-board reader are energy generators and readers attached to the train. The WBST is distributed and installed on the tracks along the train route and is configured to collect track condition data as the train passes. The on-board energy generator can generate radio frequency energy (RF energy) to power the WBST. The on-board reader can receive the track condition data sent by the WBST, determine whether the data exceeds the safety threshold, and then forward it to the control center for further analysis.

[0031] Specifically, Figure 1 A schematic diagram of a sensing technology solution of a battery-free and radio frequency powered railway monitoring system 100 is shown according to an embodiment of the present invention. Figure 1 The schematic diagram illustrates the operating principle of a battery-free, RF-powered railway monitoring system 100, which utilizes WBST to monitor track conditions. The battery-free, RF-powered railway monitoring system 100 can be installed on a train 102 and along tracks 104 along its route. Wireless communication units on the train can transmit collected data to a control center, thereby enabling battery-free, automated railway health monitoring and maintenance planning.

[0032] The battery-free, RF-powered railroad monitoring system 100 includes an onboard energy generator 110 , a WBST 112 , one or more onboard readers 114 , a base station 116 , a server 118 , a control center 120 , and a planning dashboard 122 .

[0033] The onboard energy generator 110 is located at the bottom of the train 102, and the onboard reader 114 is located at the top of the train 102. Both the onboard energy generator 110 and the onboard reader 114 are set up in accordance with safety standards. Figure 1 Only one onboard reader 114 is shown, but the present invention can also install multiple onboard readers on different cars of the train 102. The WBST 112 is arranged along the track. In various embodiments, the WBST 112 can be fixed and installed on the track 104 along the train route.

[0034] The onboard energy generator 110 is configured to transmit RF energy to the WBST 112 for powering. As the train 102 passes by, RF energy can be wirelessly transmitted from the onboard energy generator 110 to the WBST 112, providing the necessary power for WBST 112 to operate. This operation does not require any internal batteries attached to the track 104. Therefore, the WBST 112 is configured without batteries and can be powered solely by RF energy provided by the onboard energy generator 110. Furthermore, the onboard energy generator 110 attached to the train 102 can continuously charge the WBST 112 while the train is in motion.

[0035] Thus, the onboard energy generator 110 can function as a train-mounted RF energy transmitter, and the WBST 112 can collect operating parameters of the track 104 along the train route as the train 102 passes by. The operating parameters of the track 104, also known as track parameters, can reflect track conditions. The WBST 112, stationed along the train route, is configured to obtain at least one track parameter. When multiple WBSTs 112 are deployed along the train route, track data collected from the WBSTs 112 deployed along the train route can enable continuous monitoring of one or more track parameters. This arrangement ensures that the necessary track parameters are fully collected within the desired monitoring section.

[0036] In some embodiments, the WBST 112 includes sensors for collecting parameters such as vibration, temperature, and structural integrity measurements, or a combination thereof, to assess the track condition of the track 104. For example, various sensors may be integrated into the WBST 112, including accelerometers, temperature sensors, and strain gauges. Furthermore, the data transmitted by the WBST 112 may include location information in addition to the track condition of the track 104. Once the WBST 112 receives RF energy from the onboard energy generator 110, it may be activated and wirelessly transmit the collected data (e.g., sensor measurements and location information) to the onboard reader 114 to obtain the structural condition of the track. Therefore, the data collected by the sensors of the WBST 112 can also be used to assess the structural condition of the track.

[0037] In some embodiments, during the process of monitoring track conditions, energy transfer between the onboard energy generator 110 and the WBST 112 can be achieved through continuous RF transmission, while signal communication between the WBST 112 and the onboard reader 114 can also be achieved through continuous RF transmission. In some embodiments, the frequency of the RF power used for energy transfer is different from the frequency of the RF signal used for communication.

[0038] The onboard reader 114 is configured to receive data transmitted from the WBST 112 and is capable of obtaining track conditions of the track 104 disposed along the train route beneath the moving train 102 as measured by the WBST 112. In one embodiment, one or more of the onboard readers 114 are configured for continuous measurement purposes and are capable of receiving one or more track parameters from the WBST 112 located stationary along the train route. The onboard reader 114 is capable of processing the data and determining whether the track conditions meet predefined safety thresholds, thereby assessing whether any portion or part of the track 104 along the train route is damaged. If an anomaly is detected, the onboard reader 114 is activated and emits a signal or transmits data; for example, the onboard reader 114 may transmit the data to the base station 116 for further processing.

[0039] In some embodiments, a number of predefined safety thresholds can be set on the onboard reader 114. These safety thresholds correspond to various physical parameters, including vibration, temperature, and structural integrity measurements (e.g., strain). After the onboard reader 114 receives data from the WBST 112, the onboard reader 114 can perform a preliminary assessment by comparing the measured values ​​against these predefined safety thresholds. If any monitored parameter exceeds acceptable limits, indicating a possible track anomaly, the onboard reader 114 will flag the anomaly and transmit the data to the base station 116 for further processing and in-depth analysis.

[0040] In order to more effectively utilize the WBST 112 to physically measure and monitor damage to the train line track, different configuration rules can be applied to the WBST 112 placed along the train route to optimize monitoring accuracy and efficiency. For example, the configuration rules can be expanded to take into account curvature radius, train speed changes, and environmental factors.

[0041] In embodiments involving consideration of track curvature, the density of WBSTs 112 within curved sections of the track can be adjusted based on the radius of curvature. For sharp curves with smaller radii, a higher density of WBSTs 112 is expected to be required to collect structural integrity data, including track deformation, stress distribution, and vibration changes caused by train movement. Because the track 104 is subject to greater lateral forces and stress concentrations under these conditions, increasing the density of WBSTs 112 placement will help provide high-level monitoring of specific points within the curve for potential anomalies. Conversely, within shallower curves with larger radii, where structural stresses and dynamic impacts on the track 104 are lower, a lower density of WBSTs 112 per unit length can be employed, sufficient to maintain effective monitoring coverage.

[0042] In embodiments that account for varying train speeds, the number of WBSTs 112 per unit length can also vary based on the expected speed of the train 102 on different track sections. In urban areas or densely built-up areas where train speeds are lower, WBSTs 112 can be spaced farther apart because the reduced speeds are expected to result in less stress and fewer sudden forces acting on the track 104. However, in high-speed sections or uninhabited areas where the train 102 is expected to operate at significantly higher speeds, the density of WBSTs 112 can be increased to provide more intensive real-time monitoring. This higher placement density helps better track track integrity, temperature variations, and potential anomalies. These factors can become more pronounced when the train 102 is traveling at higher speeds, where greater forces can be expected on the track 104.

[0043] Figure 2 According to an embodiment of the present invention, a schematic diagram of the architecture of the train reader 114 that can interact with other components is shown. Figure 1 and Figure 2 As shown, the onboard reader 114 communicates with a base station 116; the base station 116 communicates with a server 118; the server 118 communicates with a control center 120; and the control center 120 communicates with a planning dashboard 122. In addition, the train 102 includes a monitor 106 that communicates with the onboard reader 114 and the control center 120 and is used to display the operating status of the track along the train route in real time.

[0044] Base station 116 acts as an intermediate communication hub, transmitting received track data from onboard readers 114 to server 118. Server 118 stores and organizes the data for long-term analysis and monitoring of track conditions along the train's route. Control center 120 retrieves data from server 118 and performs real-time analysis of track conditions along the train's route. If anomalies such as loose bolts, high-temperature deformation, or track cracks are detected, control center 120 can trigger an alarm and notify maintenance personnel to perform necessary intervention. Furthermore, control center 120 can use the data collected from WBST 112 to generate a maintenance plan and display it on a planning dashboard 122. Based on long-term trend analysis, the implemented methods help optimize maintenance plans, reduce operational downtime, and improve railway safety.

[0045] During processing, onboard reader 114 can perform a preliminary assessment of track conditions based on the data received from WBST 112. Train 102 is also equipped with at least one onboard reader 114, which can obtain one or more track parameters through discrete inspections, providing insight into the health of the railway system. Track parameters can help detect potential problems, such as broken rails, deformed rails, or loose rails, thereby reducing the likelihood of derailment. Thus, onboard reader 114 can assess track parameters to determine if any part or portion of track 104 is damaged.

[0046] In response to the damage detected, the onboard reader 114 is further configured to cooperate with the control center 120 to manage the railway system, thereby enabling a responsive assessment of the damage detected in one or more locations of the track 104. The purpose of the assessment is to confirm or quantify the extent of the sensed damage. When damage is confirmed or further quantified, the onboard reader 114 can mark the damaged portion of the track 104 and continuously monitor the marked damaged portion to maintain a continuous assessment thereof.

[0047] When onboard readers 114 receive data exceeding predefined safety thresholds, alerts can be immediately sent to monitors 106 on train 102 and control center 120, enabling a rapid response to potential issues. For example, train drivers can monitor the real-time status of track 104 and take necessary preventative measures if an anomaly is detected. Simultaneously, control center 120 processes the detected data and uses it as a basis for planning maintenance schedules and optimizing track repair strategies.

[0048] In addition, the onboard reader 114 is configured to receive track parameters and further obtain geographically and temporally discrete information. The track can be continuously monitored between multiple discrete inspections to provide a comprehensive condition assessment. These inspections can be performed at different, non-overlapping time periods or locations, maximizing the accuracy of tracking local and long-term structural changes to the track. This continuous monitoring process allows for the development of a response system and the confirmation and quantification of any detected damage, thereby improving railway safety and operational efficiency.

[0049] As described above, the onboard reader 114 performs a preliminary assessment. For example, the onboard reader 114 can automatically process track operational data by comparing the captured data against predefined safety thresholds. If the collected data significantly exceeds the predefined thresholds, and any abnormal parameter exceeds the safety standard threshold, the onboard reader 114 will generate an alarm signal to notify the train 102 of a potential traffic accident. The onboard reader 114 may also issue a preliminary alarm to the train 102 and display a warning prompt on the monitor 106 for the train operator's attention.

[0050] At the same time, the control center 120 performs further analysis based on track parameters that exceed predefined safety thresholds. The analysis by the control center 120 is intended to detect potential traffic accidents, including train derailment due to loose bolts, high temperature deformation, or a combination thereof.

[0051] The control center 120 includes an anomaly trend database. The anomaly trend database stores various parameter configurations related to potential traffic accidents. These parameters are composed of various physical measurements, including vibration, temperature, and structural integrity. By utilizing the anomaly trend database, the control center 120 can compare incoming data with high-risk parameter thresholds. If the detected value closely matches the predefined high-risk condition, it indicates the presence of a potential anomaly in the track 104. In addition, because multiple WBSTs 112 are deployed at the track 104 along the train route and equipped with location information, the control center 120 can not only detect anomalies but also determine the potential location of these irregularities, thereby achieving precise fault location. In one embodiment, if an irregularity is detected that has changed significantly compared to the previous run but does not exceed safety limits, the control center 120 updates the anomaly trend database but does not issue a warning report.

[0052] Control center 120 includes computing equipment capable of processing the acquired data to further calculate physical parameters. By analyzing the acquired parameters, the computing equipment can derive additional physical indicators, such as the relative position and relative motion of the tracks. This functionality enables the system to assess track conditions from multiple perspectives. In one embodiment, control center 120 compares at least one of the relative position and relative motion of the tracks to a predetermined safety threshold. If the predetermined safety threshold is exceeded, control center 120 marks the affected track, indicating that it requires inspection.

[0053] In one embodiment, when an irregularity on the track is detected that could adversely affect train safety, the control center 120 generates an alarm signal to notify the train of the presence of the irregularity if the detected irregularity meets preselected criteria. For example, if an irregularity that could affect train safety is detected due to track unevenness, the control center 120 will analyze the data to assess the extent of the irregularity and determine its cause (e.g., whether it is due to temperature changes or rail displacement in the track 104). If the severity or nature of the irregularity meets the predefined alarm conditions, the system will generate an alarm signal to notify the train of the presence of the irregularity, including its exact location.

[0054] Control center 120 can process both directly received physical parameters and physical parameters derived through computing devices. For example, when acceleration or temperature levels exceed predefined limits, control center 120 can use computing devices to detect a threshold event occurring in at least one car of train 102. Upon detection, the computing device can determine whether the threshold event occurred only in a single railcar or also occurred in one or more other train cars within a specified timeframe.

[0055] In one embodiment, the control center 120 may be configured to perform real-time monitoring and generate alerts based on analysis of sensor data. Near-real-time visual alerts of faulty track sections associated with at least one WBST 112 may be displayed on a monitor 106 or other designated notification screen on the train 102. For example, the control center 120 may generate maintenance reminders and early warning notifications, and the reminders and notifications may be displayed on appropriate monitoring interfaces.

[0056] The control center 120 can be configured to generate a maintenance plan based on a comprehensive analysis of track conditions and historical anomaly data. For example, based on the analyzed data, the control center 120 can calculate the remaining life of the railway infrastructure and develop an optimized maintenance plan. The developed plan is then transmitted to the planning dashboard 122, where it is displayed to the railway operator and maintenance team. The maintenance plan includes the scheduled time for maintenance operations and the specific maintenance tasks to be performed, such as track realignment, bolt tightening, or checking for temperature-induced rail expansion.

[0057] Furthermore, the control center 120 can estimate whether there is a potential deviation in the speed of the train 102 by analyzing the time interval between charging and data transmission of the WBST 112. For example, the control center 120 can analyze and estimate the train speed based on the time delay, or detect a speed deviation and trigger an alarm.

[0058] Regarding estimating train speed using time delay analysis, control center 120 can determine train speed by analyzing the activation timestamp and data transmission timestamp of each WBST 112. Based on the train's planned speed, the expected time interval between data transmissions between two adjacent and consecutive WBSTs 112 can be calculated. If the actual transmission time interval deviates from the expected value, it may indicate that the train 102 is traveling faster or slower than expected.

[0059] Regarding detecting speed deviations and triggering alarms, if the measured activation intervals of WBST 112 indicate that a train is moving slower than expected, this could be due to unplanned delays, braking events, or operational inefficiencies. Conversely, if a train is traveling faster than expected, this could indicate excessive acceleration, a potential safety violation, or a deviation from the scheduled operating schedule. When a significant speed deviation is detected, control center 120 can trigger an alarm to adjust speed in real time and confirm that the train is adhering to operational safety protocols.

[0060] The real-time solution proposed by this invention enables maintenance personnel to promptly repair any anomalies on the track, thereby reducing the possibility of accidents. In addition, managers can optimize the frequency of routine maintenance based on the collected data to minimize the impact on the normal operation of the train system.

[0061] Figure 3 A schematic block diagram showing how electrical energy is transferred to accomplish communication according to an embodiment of the present invention. Figure 3 The energy flow and communication architecture of the WBST can be explained. Each WBST can be composed of a dual-band antenna, energy harvesting circuits, and an embedded system. The dual-band antenna has two purposes: (1) receiving RF energy from an on-board energy generator at a frequency of 915 MHz to power the WBST; and (2) wirelessly transmitting sensor data to an on-board reader at a frequency of 433 MHz. In the system architecture, both the 915 MHz and 433 MHz frequencies used are unlicensed bands and can be used immediately after installation.

[0062] The energy harvesting layout consists of a mini-branch-line coupler (Mini-BLC), two impedance matching networks, and two Dickson voltage multipliers. The Mini-BLC splits the harvested RF energy into two equal parts and feeds them to the energy harvesting (EH) circuit, minimizing return loss caused by impedance mismatch and improving energy conversion efficiency. A rectifier converts the received AC RF signal into DC power, while a capacitor stores the energy for stable operation.

[0063] To maintain continuous operation, a power management unit (PMU) regulates and stabilizes voltage before supplying power to the embedded system, which includes a microcontroller unit (MCU), sensors, and an RF module. The MCU reads sensor data, such as vibration, temperature, and structural integrity parameters, and transmits the processed data to an onboard reader for real-time monitoring and further analysis.

[0064] Figure 4A A schematic diagram of the system architecture of a roadside battery-free sensor tag (WBMT) is shown according to an embodiment of the present invention. A detailed architecture of the WBMT is provided, including an EH antenna, EH circuit, PMU, embedded system, and communication antenna. The EH circuit converts RF energy into usable DC power. Because the harvested RF energy is intermittent, the system employs a nanopower energy harvesting power converter (such as the LTC3588), which has an efficiency of approximately 82%, making it a suitable DC-DC conversion solution. The PMU provides a constant output voltage of 2.5V, enabling stable operation of the embedded system. In addition, to minimize leakage current, the LTC3588 includes an undervoltage lockout detector that maintains the PMU in a high-impedance state while the storage capacitor is charging.

[0065] The embedded system integrates a microcontroller unit (STM32L151), sensors (ADXL362 for acceleration measurement and LMT85 for temperature measurement), and an RF communication module (CC1101). The RF module wirelessly transmits sensor data to an onboard reader for real-time track condition assessment. To evaluate the system's power consumption, a 2.5Ω resistor is also connected in series, allowing the current across the resistor to be measured.

[0066] Figure 4B A detailed view of the embedded system, power management unit (PMU), energy harvesting (EH) circuit and communication antenna is provided, such as Figure 4B As shown, each module in the system can be connected through pin headers. Figure 4C Figure 2 shows the measured power consumption of the WBMT. The power profile indicates the different operating phases. Startup Phase (~10 milliseconds): The system requires an initial power surge to activate. Initialization Phase (~8 milliseconds): The system stabilizes and prepares for measurement. Measurement and Data Transfer (~3 milliseconds): The WBMT collects sensor data and transmits it wirelessly. To minimize response time, the available energy stored in the storage capacitor is only sufficient to support the system's cold start and the first data transmission. Subsequent transmissions require additional harvested energy to maintain continuous operation.

[0067] Figure 5A 、 Figure 5B and Figure 5C A schematic diagram of a design scheme of a miniature branch line coupler (mini-BLC) is shown according to an embodiment of the present invention. Figure 5AAs shown in Figure 1, a conventional branch-line coupler (BLC) consists of four quarter-wavelength transmission line branches with either 50Ω or 35Ω impedance. When power enters port 1, it is equally split between ports 2 and 3, introducing a 90° phase difference between the two output ports. Port 4, known as the isolation port, is theoretically designed to receive minimum signal power due to the coupler's inherent isolation properties. Ideally, all incident power at port 1 is split between ports 2 and 3, while port 4 receives negligible or no power.

[0068] Figure 5B The equivalent open-circuit stub configurations for converting the original transmission line (Z, θ) into π- and T-shapes are shown. Compared to the T-shape model, the π-shape model with two shunt open-circuit stubs (Z2, θ2) can contribute more to size reduction, making it a more compact design choice. In addition, Figure 5C An additional miniaturization step achieved through simulation-based optimization is demonstrated. By folding the open-circuit stub structure, the overall coupler size is further minimized while maintaining its impedance characteristics and performance.

[0069] Figure 6A 、 Figure 6B and Figure 6C The performance comparison graph of the conventional mini-BLC and the proposed mini-BLC is shown. Figure 6A The physical layout of a conventional BLC and a micro BLC is shown. The micro BLC achieves a significantly smaller footprint, with an overall size of 26 mm × 21 mm, an 80% reduction compared to conventional designs. Figure 6B The measured phase difference is shown, which remains at 90 degrees at 915 MHz. Figure 6C Measured S-parameters are provided, illustrating the electrical performance of both designs. At 915 MHz, return loss (S11) and isolation (S41) are less than -17 dB and -20 dB, respectively, demonstrating effective impedance matching and minimal unwanted signal leakage. Furthermore, S21 and S31 are measured at -3.38 dB and -3.45 dB, respectively, confirming effective power distribution between the output ports. The bandwidths for S11 < -15 dB and S41 < -15 dB are 2.2% and 20.7%, respectively, indicating that the micro-BLC offers slightly lower insertion loss (<15 dB) than the traditional BLC while maintaining acceptable electrical performance. This demonstrates that miniaturization allows for effective size optimization without significant performance degradation.

[0070] Figure 7A 、 Figure 7B 、 Figure 7C and Figure 7DA comparison diagram between the proposed energy harvesting scheme and the traditional scheme (using a 4-level Dickson voltage multiplier (DVM) without a branchless coupler (BLC)) is shown. Figure 7A and Figure 7B The voltage variation of a conventional solution at 3dBm input power is shown. The system requires 1.1 seconds to complete a cold start, after which the rectifier output voltage oscillates between 3V and 4V. During each operating cycle, the WBMT initializes, measures, and transmits data. However, due to limited energy storage capacity, the capacitor can only support the transmission of one data frame, forcing the WBMT to shut down and require recharging before the next cycle. Figure 7C and Figure 7D The voltage response of the proposed scheme is shown. The proposed scheme combines two rectifiers that simultaneously harvest RF energy. However, due to energy losses and impedance mismatch, the rectifiers alternately supply energy to the embedded system. Although the proposed scheme requires a longer startup time, the charging interval is also shorter due to the slower voltage drop across the capacitor component. In the proposed dual-rectifier system, Mini-BLC is used to redistribute the rectifiers' high-efficiency operating region to a higher input power range, thereby improving efficiency.

[0071] As mentioned above, the battery-free and maintenance-free design of the RF-powered railway monitoring system reduces the time and labor costs associated with railway inspections. Furthermore, since the railway monitoring system does not occupy the core space of the railway track during operation, it does not interfere with the normal use of the railway monitoring system. In addition to railway monitoring, the design method of the RF-powered railway monitoring system can also be extended to other difficult-to-access environments for object monitoring applications, such as offshore wind turbines, bridges, and tunnels. In addition, the WBST can be designed using advanced CMOS (complementary metal oxide semiconductor) technology to achieve a more compact form factor and higher-resolution measurements, thereby improving the accuracy and efficiency of infrastructure monitoring.

[0072] In summary, the present invention relates to a method for designing an automatic track monitoring system, also known as a battery-free, radio-frequency-powered railway monitoring system. This system monitors tracks and detects potential hazards that could pose safety risks or lead to derailments. The system can operate continuously during normal railway service. It consists of an onboard device and a wirelessly powered track monitoring system (WBST). The onboard device wirelessly charges the WBST using radio frequency energy. As trains pass by, the WBST collects data such as track vibration and temperature, which is then transmitted back to the onboard device.

[0073] The functional units and modules of the apparatus and methods according to the embodiments disclosed herein can be implemented using computing devices, computer processors, or electronic circuits, including but not limited to application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), microcontrollers, and other programmable logic devices configured or programmed according to the teachings of the present disclosure. Those skilled in the art of software or electronics can easily prepare computer instructions or software codes executed in computing devices, computer processors, or programmable logic devices based on the teachings of the present disclosure.

[0074] All or part of the method according to the embodiment may be executed in one or more computing devices, including server computers, personal computers, laptop computers, and mobile computing devices (such as smartphones and tablet computers).

[0075] Embodiments may include computer storage media, transient and non-transitory memory devices having computer instructions or software code stored therein, which may be used to program or configure a computing device, computer processor, or electronic circuit to perform any of the processes of the present invention. Storage media, transient and non-transitory memory devices may include, but are not limited to, floppy disks, optical disks, Blu-ray disks, DVDs, CD-ROMs, magneto-optical disks, ROMs, RAMs, flash memory devices, or any type of medium or device suitable for storing instructions, code, and / or data.

[0076] Each functional unit and module according to various embodiments may also be implemented in a distributed computing environment and / or a cloud computing environment, where all or part of the machine instructions are executed in a distributed manner by one or more processing devices that are interconnected by a communication network, such as an intranet, a wide area network (WAN), a local area network (LAN), the Internet, and other forms of data transmission media.

[0077] The foregoing description of the present invention is provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations will be apparent to those skilled in the art.

[0078] The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated.

Claims

1. A battery-free and radio frequency powered railway monitoring system, characterized in that: include: A plurality of on-board energy generators are provided on the train; Multiple roadside battery-free sensing tags (Wayside Battery-free Sensing Tag; A WBST is fixedly installed on a track along a train route, wherein the train runs along the track according to a predetermined train route, and the on-board energy generator is configured to wirelessly transmit radio frequency energy to the WBST for powering when the train passes, so that the WBST does not need to be connected to a battery and is only powered by the radio frequency energy provided by the on-board energy generator, and wherein the WBST is configured to collect track parameters of the track laid along the train route to continuously monitor one or more track parameters when the train passes; at least one onboard reader, disposed on the train, for receiving data transmitted from the WBST, thereby obtaining track conditions of the track beneath the moving train, wherein the onboard reader processes the data and determines whether the track conditions meet a predefined safety threshold, thereby evaluating whether any of the rails or any section of the track on the track is damaged, and if an anomaly is detected, the onboard reader is activated and emits a signal or transmits data; a base station, serving as an intermediate communication hub, receiving track data from the onboard readers; a server that stores and organizes the track data from the base stations for long-term analysis and railway condition monitoring; and A control center retrieves data from the server and performs real-time analysis of the track condition of the railway, wherein if an anomaly is detected, the control center triggers an alarm and notifies an external system.

2. The system according to claim 1, wherein: The anomalies include events related to loosening of rail bolts, deformation of rails due to high temperatures, or cracking of rails.

3. The system according to claim 1, wherein: Energy transmission between the on-board energy generator and the WBST is achieved through radio frequency transmission, and signal communication between the WBST and the on-board reader is achieved through radio frequency transmission.

4. The system according to claim 3, characterized in that The frequency of the radio frequency power used for the energy transmission is different from the frequency of the radio frequency signal used for the signal communication.

5. The system according to claim 1, wherein: The WBST includes sensors for collecting the track parameters, and the track parameters include vibration, temperature, structural integrity measurements, or a combination thereof.

6. The system according to claim 5, characterized in that The sensors integrated into the WBST include accelerometers, temperature sensors, and strain gauges.

7. The system according to claim 6, characterized in that The data transmitted by the WBST includes the position information of the track, and once the WBST receives the radio frequency energy from the onboard energy generator, the WBST is activated and wirelessly transmits the position information to the onboard reader.

8. The system according to claim 1, wherein: The onboard reader is provided with a plurality of predefined safety thresholds corresponding to various physical parameters, including vibration, temperature, and structural integrity measurements, and, upon receiving data from the WBST, the onboard reader performs a preliminary assessment by comparing the measured values ​​with the predefined safety thresholds, and if any monitored parameters in the data exceed acceptable limits, the onboard reader transmits the data to the base station for further processing and in-depth analysis.

9. The system according to claim 1, wherein: The control center generates a maintenance plan using the data collected from the WBST, and the maintenance plan is displayed on a plan dashboard.

10. The system according to claim 1, wherein: The onboard reader is further configured to receive the track parameters as geographically and temporally discrete information, thereby enabling continuous monitoring of the track between multiple discrete inspections, wherein the discrete inspections performed by the onboard reader are for different and non-overlapping time periods or locations.

11. The system according to claim 1, wherein: The onboard reader is used to issue a preliminary alert to the train when the track condition exceeds a predefined safety threshold and display a warning signal on a monitor of the train.

12. The system according to claim 1, wherein: The control center includes an anomaly trend database that stores a plurality of high-risk parameter configurations associated with potential traffic accidents, the high-risk parameter configurations being constructed from various physical measurements, including vibration, temperature, and structural integrity. The control center compares the incoming data with high-risk parameter thresholds, and if the detected values ​​highly match the conditions defined by the high-risk parameter thresholds, the control center indicates the presence of a potential anomaly in the track.

13. The system according to claim 12, wherein: The control center not only detects anomalies but also determines potential locations of irregular events by using the WBSTs deployed on the tracks along the train route and equipped with location information.

14. The system according to claim 12, wherein: If an irregular event is detected, and the irregular event has a significant change compared with the previous operation but does not exceed the safety limit, the control center updates the abnormal trend database but does not issue a warning report.

15. The system according to claim 12, wherein: When a track irregularity event that has an adverse effect on the safety of the train is detected, the control center generates an alarm signal to notify the occurrence of the track irregularity event if the detected track irregularity event meets preselected criteria.

16. The system according to claim 12, wherein: The control center also includes a computing device for processing the acquired data to perform physical parameter calculations and to derive physical indicators of the track, including relative position and relative motion, wherein the control center compares at least one factor of the relative position and relative motion of the track with a predetermined safety standard threshold.

17. The system according to claim 16, wherein: The control center also utilizes the computing device to detect a threshold event occurring in at least one rail car of the train when acceleration or temperature levels exceed predefined limits, and upon detection, the computing device determines whether the threshold event occurred only in the single rail car or also occurred in one or more other train cars within a specified time frame.

18. The system according to claim 16, wherein: The control center analyzes the activation and data transmission timestamps of each WBST and calculates the expected time interval for data transmission between two adjacent and consecutive WBSTs based on the planned speed of the train.

19. The system according to claim 1, wherein: The deployment density of the WBST is based on the curvature radius of the track, and for sharp turns with a smaller radius in the train route, a higher number density of the WBST is adopted, while for gentle turns with a larger radius in the train route, a lower number density of the WBST is adopted.

20. The system according to claim 1, wherein: The number of WBSTs per unit length is arranged to vary depending on the expected train speed for different track sections.

Images