A belt conveyor state monitoring and speed regulating system based on intelligent roller group

Abstract

The application discloses a kind of based on intelligent group of supporting roller belt conveyor state monitoring and speed regulation system, including integrated embedded in supporting roller internal wireless sensor node;Wireless sensor node includes energy collection module, energy management module and wireless sensor node module;Energy collection module is used to convert the mechanical energy of supporting roller rotation into alternating current energy;It includes stator assembly and rotor assembly;Stator assembly is fixed to supporting roller shaft, and rotor assembly is fixed to supporting roller bearing seat;Energy management module is connected with energy collection module, for the management of alternating current energy and power supply for wireless sensor node module;Energy management module includes H bridge circuit output positive or reverse direct current;The output end of H bridge circuit is connected with the stator assembly of energy collection module, for the positive or reverse direct current that stator assembly is imported;By this, the same set of electromagnetic mechanism can be intelligently switched between power generation mode and electric mode.

Description

Technical Field

[0001] This invention relates to the field of belt conveyor technology, and in particular to a belt conveyor status monitoring and speed regulation system based on intelligent idler groups. Background Technology

[0002] Belt conveyors are crucial continuous transportation equipment in coal mining, and their operating status directly affects the safety and production efficiency of coal mines. Among them, idlers, as the core load-bearing and rotating components of belt conveyors, are numerous and operate under harsh conditions of high load, high dust, and strong impact for extended periods, making them one of the components with the highest failure rate in the entire machine.

[0003] Traditional methods for monitoring the condition of idler rollers mainly rely on external sensors or periodic manual inspections. However, external sensors are easily damaged by direct impacts from materials such as coal and gangue, and the collected signals are severely affected by environmental noise, making it difficult to guarantee accuracy. Manual inspections, on the other hand, suffer from low efficiency, poor real-time performance, and significant safety hazards.

[0004] In recent years, solutions have emerged that integrate sensors into idler rollers in order to obtain more direct and accurate in-situ monitoring data. However, built-in monitoring solutions face several prominent technical challenges.

[0005] First, the internal space of the idler roller is small and it is in a continuous rotating state, making it difficult to provide wired power. If battery power is used, it needs to be replaced frequently, resulting in extremely high maintenance costs and operational risks.

[0006] Secondly, the metal roller shell will have a strong shielding effect on wireless signals, causing the built-in antenna to fail, while the external antenna is very easy to be damaged under harsh working conditions.

[0007] Third, as a passively rotating component, the idler roller's rotational speed needs to be coordinated with the active drive belt's rotational speed; otherwise, it will exacerbate wear and even cause malfunctions. Existing technologies lack an effective mechanism for dynamically and adaptively controlling the idler roller's rotational speed based on the belt speed.

[0008] Fourth, a single belt conveyor often has hundreds or thousands of idlers, forming a huge monitoring cluster. The massive amount of monitoring data can easily cause network congestion during transmission, leading to the loss of critical fault information and making it difficult to achieve high-quality, high-reliability networked cluster monitoring.

[0009] Therefore, there is an urgent need for an intelligent idler monitoring system that can achieve self-powered operation, anti-interference, coordinated speed regulation, and reliable processing of massive amounts of data. Summary of the Invention

[0010] The technical problem solved by this invention is that existing technologies are unable to achieve efficient power supply, reliable anti-interference communication, adaptive and coordinated speed regulation with the belt, and reliable networked monitoring of massive node data on belt conveyor idlers.

[0011] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a belt conveyor status monitoring and speed regulation system based on intelligent idler groups, including wireless sensor nodes integrated and embedded inside the idlers.

[0012] The wireless sensor node includes an energy harvesting module, an energy management module, and a wireless sensor node module.

[0013] The energy harvesting module is used to convert the mechanical energy of the rotating idler into alternating current; it includes a stator assembly and a rotor assembly; the stator assembly is fixed to the idler shaft, and the rotor assembly is fixed to the idler bearing housing.

[0014] The energy management module is connected to the energy harvesting module and is used to manage the AC power and supply power to the wireless sensor node module.

[0015] The energy management module includes an H-bridge circuit, which consists of four switching elements. The switching elements are controlled to turn on and off by a preset adjustment strategy to output forward or reverse DC power. The output terminal of the H-bridge circuit is connected to the stator assembly of the energy harvesting module to supply forward or reverse DC power to the stator assembly.

[0016] Preferably, the energy management module further includes a voltage conditioning circuit electrically connected to the energy harvesting module, used to convert the AC power output by the energy harvesting module into DC voltage.

[0017] A charging management logic circuit, connected to an energy storage battery, is used to manage the charging and discharging of the energy storage battery.

[0018] Preferably, the voltage conditioning circuit uses a TPS63070 chip; the charging management logic circuit uses an SGM41524 chip.

[0019] Preferably, the wireless sensor node module includes a low-power microcontroller, and a vibration sensor, a temperature sensor, and a sound sensor connected to the low-power microcontroller; wherein the vibration sensor, temperature sensor, and sound sensor are used to collect the status information of the idler roller.

[0020] Preferably, it also includes a conformal antenna device.

[0021] The conformal antenna device includes an antenna housing and an antenna disposed within the antenna housing.

[0022] The end of the idler roller shaft is provided with a mounting groove.

[0023] The antenna housing is embedded in the mounting slot, and the shape of the antenna housing is consistent with that of the mounting slot.

[0024] Preferably, the adjustment strategy includes the following steps: determining the working condition type of each idler roller according to the installation layout of the belt conveyor.

[0025] The actual rotational speed of the idler rollers and the real-time rotational speed of the belt conveyor are obtained in real time.

[0026] The target speed of the idler is calculated based on the real-time rotational speed of the belt conveyor and the operating condition of the idler.

[0027] Calculate the deviation between the actual rotational speed of the idler roller and the target rotational speed.

[0028] If the deviation of the idler exceeds the speed regulation activation threshold corresponding to its operating condition type, directional DC current is supplied to the stator assembly of the energy harvesting module through the energy management module to adjust the idler speed. The direction of the directional DC current is determined according to the direction of the deviation and the operating condition type.

[0029] Preferably, the formula for calculating the actual rotational speed is as follows: ;in, This refers to the actual rotational speed of the idler roller. The pulse frequency of the output voltage of the energy harvesting module. denoted as the number of pole pairs of the rotor permanent magnet.

[0030] Preferably, the plurality of wireless sensor nodes, together with the routing nodes and coordinator nodes deployed along the belt conveyor, constitute a hierarchical wireless network. The coordinator node is used to coordinate the data upload scheduling in the network according to the instructions of the adjustment strategy or the priority of the monitoring data. The wireless sensor node module is configured to execute an adaptive monitoring strategy.

[0031] When the data collected by the vibration sensor, temperature sensor and battery voltage monitoring module are within the corresponding preset normal threshold range, a time-driven polling mode is adopted, and the working duty cycle and data sampling frequency are dynamically adjusted according to the load status of the belt conveyor.

[0032] When any of the vibration, temperature, or battery voltage data exceeds its corresponding preset normal threshold range, the system switches to event-driven continuous monitoring mode, adjusting the duty cycle and data sampling frequency to their maximum values.

[0033] The beneficial effects of this invention are as follows: First, the belt conveyor status monitoring and speed regulation system based on intelligent idler groups provided by this invention, through the adoption of an integrated hardware architecture that connects the stator coil of the energy harvesting module to the output of the H-bridge circuit, enables the same electromagnetic mechanism to intelligently switch between power generation mode and electric mode. That is, this system can generate electricity to power the wireless sensors for status monitoring during rotation, and can also be powered as a motor when speed regulation is required. In this way, this invention eliminates the problems of difficult wiring of the built-in wireless sensor power supply cables and inconvenient battery replacement, and gives the passive idler rollers the dual technical effect of actively following the belt speed for dynamic fine-tuning, achieving a fundamental transformation from "passive monitoring" to "self-sufficiency and active collaboration".

[0034] Secondly, the belt conveyor status monitoring and speed control system based on intelligent idler groups provided by this invention solves the problems of severe shielding of wireless signals by the metal roller shell and easy damage to external antennas under harsh working conditions by designing an embedded conformal antenna device that matches the shape of the mounting groove on the idler shaft. Thus, this invention integrates the antenna into the mounting groove through precision machining, making the outer surface of the antenna flush with the roller shaft. This achieves the dual technical effect of physically protecting the antenna from direct impact while effectively avoiding metal shielding to ensure signal radiation efficiency. This improves the long-term reliability of wireless transmission of monitoring data in high-dust, high-impact environments such as coal mines.

[0035] Third, the belt conveyor condition monitoring and speed control system based on intelligent idler groups provided by this invention solves the problem of uneven wear and belt misalignment caused by the difficulty in globally coordinating the speeds of the idler groups and the belt due to load and position differences by implementing an adaptive speed control strategy based on working condition division (smooth, upward, downward, and turning) and closed-loop feedback of speed deviation. This invention presets working condition parameters for each idler and dynamically calculates the target speed based on the real-time belt speed, using an H-bridge circuit for directional compensation. This achieves the technical effect of keeping the idler speed and belt speed adaptively synchronized throughout the entire line, significantly reducing frictional losses and failure risks caused by speed differences, and improving the operational stability and lifespan of the entire conveyor system.

[0036] Fourth, the belt conveyor status monitoring and speed control system based on intelligent idler groups provided by this invention solves the problems of network congestion and high latency in the transmission of critical fault information in scenarios with massive concurrent data from idler clusters by adopting a time-event dual-drive adaptive sampling strategy at the node level and constructing a hierarchical topology and priority scheduling mechanism at the network layer. Furthermore, this invention enables nodes to operate at low frequency and energy efficiency under normal conditions and to capture data at high frequency during anomalies, with the coordinator coordinating the uploading of data based on its importance. This significantly optimizes network bandwidth utilization and ensures that abnormal data is uploaded preferentially and promptly; thus, this invention provides efficient and reliable networked monitoring of the entire belt conveyor's health status. Attached Figure Description

[0037] Figure 1 This invention provides an overall assembly diagram of a belt conveyor condition monitoring and speed regulation system based on intelligent idler groups.

[0038] Figure 2 This invention provides an internal assembly diagram of a belt conveyor condition monitoring and speed control system based on an intelligent idler group.

[0039] Figure 3 for Figure 3 Sectional view of section AA.

[0040] Figure 4 This is a side view of the overall structure of a belt conveyor condition monitoring and speed regulation system based on intelligent idler groups, provided by the present invention.

[0041] Figure 5 This invention provides a schematic diagram of the main body of an energy harvesting module for a belt conveyor condition monitoring and speed regulation system based on an intelligent idler group.

[0042] Figure 6 This invention provides an energy management strategy for a belt conveyor condition monitoring and speed control system based on intelligent idler groups.

[0043] Figure 7 This invention provides a monitoring data acquisition process for a belt conveyor status monitoring and speed control system based on intelligent idler groups.

[0044] Figure 8 This invention provides a data transmission and networking process for a belt conveyor status monitoring and speed control system based on intelligent idler groups.

[0045] Figure 9 This invention provides a system for monitoring and regulating the status of a belt conveyor based on an intelligent idler group, showing the changes in generator voltage and output power at different speeds.

[0046] Figure 10 This invention provides the relationship between signal strength and communication distance of nodes under different operating conditions in a belt conveyor condition monitoring and speed regulation system based on intelligent idler groups.

[0047] Figure 11 This invention provides a test of the node sensing capability of a belt conveyor status monitoring and speed regulation system based on intelligent idler groups.

[0048] In the diagram: 1. Idler roller shell; 2. Bearing housing; 3. Idler roller shaft; 4. Energy management module; 5. Wireless sensor node; 6. Antenna; 7. Antenna housing; 8. Support component; 9. Energy storage battery; 10. Fixing ring; 11. Energy harvesting module; 12. Fixing frame; 13. Stator assembly; 14. Magnet frame; 15. Magnet. Detailed Implementation

[0049] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0050] Currently, built-in monitoring solutions face several prominent technical challenges: First, the confined space inside the idler rollers and their continuous rotation make wired power supply difficult. Battery power requires frequent replacements, resulting in high maintenance costs and operational risks. Second, the metal roller shells of the idlers strongly shield wireless signals, causing communication failures with the built-in antennas, while external antennas are easily damaged under harsh working conditions. Third, as passively rotating components, the idler rollers' rotational speed must be synchronized with the speed of the actively driven belt; otherwise, wear will be aggravated and even malfunctions may occur. Existing technologies lack an effective mechanism for dynamic and adaptive control of the idler roller speed based on the belt speed. Fourth, a single belt conveyor often deploys hundreds or thousands of idlers, forming a massive monitoring cluster. The transmission of this massive amount of monitoring data can easily cause network congestion, leading to the loss of critical fault information and making it difficult to achieve high-quality, high-reliability networked cluster monitoring.

[0051] To address the aforementioned issues, this invention provides a belt conveyor status monitoring and speed control system based on intelligent idler groups, comprising a wireless sensor node 5 integrated and embedded within the idler. The wireless sensor node 5 includes an energy harvesting module 11, an energy management module 4, and a wireless sensor node 5 module. The energy harvesting module 11 converts the mechanical energy of the idler rotation into alternating current (AC) energy. It includes a stator assembly 13 and a rotor assembly. The stator assembly 13 is fixed to the idler shaft 3, and the rotor assembly is fixed to the idler bearing seat 2. The energy management module 4 is connected to the energy harvesting module 11 and manages the AC energy and supplies power to the wireless sensor node 5 module. The energy management module 4 includes an H-bridge circuit, which consists of four switching elements. The switching elements are controlled to turn on and off using a preset adjustment strategy, outputting forward or reverse DC power. The output of the H-bridge circuit is connected to the stator assembly 13 of the energy harvesting module 11, allowing forward or reverse DC power to be supplied to the stator assembly 13.

[0052] The present invention provides a belt conveyor condition monitoring and speed control system based on intelligent idler groups, such as... Figures 1 to 4As shown, the core hardware of the entire system is a wireless sensor node 5 integrated and embedded inside the idler roller. Specifically, the main mechanical structure of the smart idler roller includes an idler roller shell 1, a bearing housing 2, and an idler roller shaft 3. The idler roller shell 1 is connected to the bearing housing 2; the bearing housing 2 is connected to the idler roller shaft 3 through a bearing, and the bearing housing 2 can rotate around the stationary idler roller shaft 3.

[0053] Specifically, all electronic modules, including the energy management module 4, the wireless sensor node 5, and the energy storage battery 9, are mounted on a custom-designed support 8. This support 8 is a high-strength engineering plastic or metal plate with positioning posts and screw holes for securing the electronic modules. The energy harvesting module 11 is a separate component; its stator assembly 13 is coaxially fitted onto the outside of the idler roller shaft 3, but its output cable is connected to the energy management module 4 on the support 8, and the cable connection is insulated with silicone. The output cables of the energy management module 4, the wireless sensor node 5, and the stator assembly 13 are secured with retaining rings 10 and finally bolted to the idler roller shaft 3. To prevent loosening of the screws due to long-term vibration, high-strength AB glue is applied to the bolt connection edges for reinforcement.

[0054] Furthermore, electromagnetic compatibility must be considered when laying out the wireless sensor node 5 module. Although it is connected to the energy harvesting module 11 via cable, its physical location should be as far away as possible from the coil and magnet 15 of the energy harvesting module 11 to reduce interference from strong alternating magnetic fields on sensitive sensor signals (especially weak vibration and sound signals). Simultaneously, the feed point of the conformal antenna 6 device should be close to the RF output port of the wireless sensor node 5 module and positioned near the end of the roller shaft 3 to optimize wireless signal radiation.

[0055] This integrated embedded design, originating from the mechanical structure, forms the basis for all subsequent functions. It ensures that the sensor can directly and in-situ perceive the real-world conditions (vibration, temperature) of the roller bearing and housing, while providing a structural platform for generating electricity using rotational kinetic energy and for torque regulation.

[0056] The energy harvesting module 11 is the cornerstone of the system's "passive" operation. Its function is to convert the mechanical energy of the rotating roller into AC electrical energy.

[0057] like Figure 5 As shown, the module is strictly divided into a stationary part and a rotating part, and this division is completely consistent with the dynamic and static structure of the idler roller itself. The stator assembly 13 is the stationary part. It consists of an iron core and copper wire coils wound around it. A through hole is opened in the center of the iron core, and it is concentrically fixed to the stationary idler roller shaft 3 through a non-magnetic fixing seat (e.g., aluminum alloy material). Typically, the stator assembly 13 is arranged at one end of the idler roller shaft 3 (e.g., ...). Figure 4 The right end of the core is positioned so that its core end face is closely adjacent to the inner end face of the bearing housing 2 at that end. The bearing housing 2 serves to axially position and constrain the stator assembly 13, preventing it from moving along the shaft.

[0058] The rotor assembly is the rotating part. It consists of an annular mounting bracket 12, an arc-shaped magnet bracket 14, and several high-performance permanent magnets. The magnet bracket 14 is typically made of a non-magnetic material (such as stainless steel) and has a fixing structure on its inner side, which is inserted into the slot of the annular mounting bracket 12. Multiple permanent magnets (such as NdFeB N52 type) are circumferentially and evenly attached or embedded on the inner circumferential surface of the magnet bracket 14 in an alternating N and S pole configuration. The number of permanent magnets determines the number of pole pairs of the generator, which is a fixed design parameter, such as 8 poles (i.e., 4 pole pairs) or 10 poles. The mounting bracket 12 is securely mounted to the inner surface of the bearing housing 2, which rotates together with the idler roller housing 1, by screws. Therefore, when the idler roller rotates, the entire rotor assembly rotates together with the bearing housing 2.

[0059] Specifically, the energy conversion principle is based on Faraday's law of electromagnetic induction. When the belt conveyor is running, the belt friction drives the idler housing 1 and bearing seat 2 to rotate, and the rotor assembly (i.e., the permanent magnet array) fixed on the bearing seat 2 rotates synchronously. Since the iron core and coil of the stator assembly 13 are fixed on the stationary idler shaft 3, a continuous relative motion occurs between the rotating permanent magnet magnetic field and the stationary coil. This causes a periodic change in the magnetic flux through each turn of the coil, thereby generating an induced electromotive force at the ends of the coil. Due to the alternating magnetic poles, the generated electromotive force is in alternating current (AC) form.

[0060] Output characteristics: The frequency of the AC voltage output by the coil has a strict linear relationship with the mechanical speed of the rotor (unit: revolutions per minute, r / min), as shown in the following formula: ;in, This refers to the actual rotational speed of the idler roller. The pulse frequency of the output voltage of the energy harvesting module 11 denoted as the number of pole pairs of the rotor permanent magnet.

[0061] Therefore, by measuring the frequency of this alternating current, the actual rotational speed of the idler roller can be deduced very accurately. This provides a crucial speed feedback signal for subsequent speed control, eliminating the need for additional photoelectric or magnetoelectric speed sensors. The amplitude of the output voltage is directly proportional to the rotational speed and magnetic flux; the higher the rotational speed, the greater the output voltage amplitude. Figure 9As shown, under typical mine operating conditions, when the idler roller speed is not less than approximately 120 r / min (corresponding to a belt linear speed of approximately 2 m / s), the output power of the energy harvesting module 11 can reach over 2W. Therefore, considering that the average power consumption of the subsequent wireless sensor node 5 module is only in the milliwatt range, the system power generation provided by this invention far exceeds the power consumption, thus truly achieving "passive" self-powered operation, with sufficient energy surplus for storage and speed regulation.

[0062] Installation Details: The power cables leading from the stator coils need to be handled properly. These cables should be distributed to avoid excessive stress from over-tight bundling, and secured to the idler roller shaft 3 using additional retaining rings 10. All welded or plugged connections must be sealed, insulated, and vibration-damped with insulating silicone to withstand the harsh environment of dampness, dust, and continuous vibration underground.

[0063] Energy management module 4 is the "energy hub" and "speed regulator" of this system. It receives raw electrical energy from energy harvesting module 11, processes, stores, and distributes it, and finally executes speed regulation commands. Figure 6 It illustrates its energy flow and management strategy.

[0064] This module integrates multiple functional circuit units, including: a voltage conditioning circuit: this circuit is directly electrically connected to the output of the energy harvesting module 11. Because the idler roller speed varies greatly with the conveyor load (from standstill to high speed), the AC voltage amplitude output by the energy harvesting module 11 also fluctuates drastically (potentially from a few volts to tens of volts), and being in AC form, it cannot directly power digital integrated circuits. Therefore, this embodiment uses the TPS63070 chip as the core to construct a high-efficiency buck-boost switching regulator. The TPS63070 can accept a wide range of input voltages (e.g., 1.8V to 5.5V) and automatically determines whether a boost or buck voltage is needed, always outputting a stable, settable DC voltage (set to 5V in this system). This stable 5V DC powers all subsequent logic chips, sensors, and communication modules.

[0065] Charging Management Logic Circuit and Energy Storage Battery 9: To address the intermittency and fluctuations in energy harvesting (e.g., insufficient power generation during roller start-up, low-speed operation, or short-term shutdown), the system must be equipped with an energy storage unit. This system includes an energy storage battery 9, such as a 1200mAh lithium thionyl chloride (Li-SOCl2) battery. This type of battery has high energy density and low self-discharge rate, making it suitable for long-term float charging applications. The charging management logic circuit, with the SGM41524 chip at its core, manages the safe and efficient charging and discharging of this battery. This circuit is connected between the voltage conditioning circuit (5V output) and the energy storage battery 9.

[0066] Its working logic is as follows: Charging: When the energy harvesting module 11 generates sufficient power, and there is a surplus of electrical energy on the 5V power rail after supplying the system's real-time consumption, the SGM41524 chip will start the charging circuit to safely store the excess electrical energy into the energy storage battery 9 with an appropriate current (e.g., constant current-constant voltage mode). The chip's built-in charging algorithm and monitoring circuit can effectively prevent the battery from being overcharged.

[0067] Discharge / System Power Supply: When the output of the energy harvesting module 11 is insufficient to support system operation (e.g., the input voltage is too low, causing the TPS63070 to be unable to maintain a 5V output), the SGM41524 chip will automatically switch the path, allowing the energy storage battery 9 to power the entire system, achieving seamless switching and ensuring continuous system operation. The chip also features undervoltage lockout (UVLO) functionality; when it detects that the battery voltage is too low, it will actively disconnect the load to prevent over-discharge of the battery, thereby protecting battery life and safety.

[0068] Through this "power generation priority, battery backup" energy management strategy, the present invention ensures that the wireless sensor node 5 can obtain a continuous and stable power supply under any operating conditions.

[0069] H-bridge circuit and its speed regulation function: This is the key hardware feature of this invention for achieving "adaptive speed regulation". The H-bridge circuit consists of four identical power switching elements, schematically shown as Q1, Q2, Q3, and Q4. These four MOSFETs are connected in a classic "H" topology: the sources of Q1 and Q2 are connected as the upper bridge arm, and the sources of Q3 and Q4 are connected as the lower bridge arm; the drains of Q1 and Q3 are connected together as output terminal A, and the drains of Q2 and Q4 are connected together as output terminal B. Output terminals A and B are directly connected to the two ends of the coil of the stator assembly 13 of the energy harvesting module 11. The power input terminal of the H-bridge is connected to the DC power supply of the system (such as 5V or battery voltage).

[0070] The circuit's operating mode is controlled by pulse signals from the microcontroller (MCU) in the wireless sensor node 5 module. The MCU precisely controls the on and off states of each MOSFET through a driver chip (such as a gate driver).

[0071] Power generation mode (default state): The MCU controls all four MOSFETs (Q1-Q4) to be in the off (shutdown) state. At this time, the two ends of the stator coil are connected to the outside through the body diodes inside the MOSFETs or the parallel detection circuit. The energy harvesting module 11 generates electricity normally, and the generated AC power is rectified to power the system. The H-bridge circuit does not consume energy in this mode and does not affect power generation.

[0072] Electric Mode (Acceleration State): When the MCU determines that the idler needs acceleration based on the algorithm described later, it will issue a control command to turn on Q1 and Q4 while keeping Q2 and Q3 off. At this time, DC current flows from the positive terminal of the power supply through Q1, the stator coil, and Q4 back to the negative terminal. We define this current direction as "positive DC". According to the left-hand rule for electric motors, the energized stator coil experiences an Ampere force in the fixed magnetic field generated by the rotor permanent magnet. Through proper winding design, this force generates an electromagnetic driving torque (Telectromagnetic) in the same direction as the idler's current rotation, equivalent to a miniature motor pushing the idler and increasing its speed.

[0073] Electric Mode (Deceleration): When deceleration is required, the MCU controls Q2 and Q3 to conduct while keeping Q1 and Q4 off. The current path changes to flow from the positive terminal of the power supply through Q2, the stator coil, and Q3 back to the negative terminal. The current direction is opposite to that during acceleration, i.e., "reverse DC". The Ampere force generated at this time is opposite to the direction of rotation, forming an electromagnetic braking torque that resists the inertia of the roller and reduces its speed.

[0074] By precisely controlling the conduction timing and pulse width of the H-bridge (i.e., controlling the current magnitude and energizing time) through the MCU, fine and stepless control of the idler roller speed can be achieved.

[0075] The wireless sensor node 5 module is used to collect multi-dimensional status information, process data, execute core algorithms, and manage communication. Specifically, it can be a multi-functional embedded system board with an ultra-low-power microcontroller (MCU) at its core.

[0076] In this embodiment, the STM32F413RGT6 is preferred as the main control MCU. This chip is based on the ARM Cortex-M4 core, has sufficient computing power to execute complex signal processing and control algorithms, and has rich analog and digital peripherals (such as ADC, DAC, timers, multiple UART / SPI / I2C channels). It is also known for its excellent low power consumption and supports multiple sleep modes, making it very suitable for the scenario in this application that requires long-term battery power.

[0077] The sensing unit specifically includes: a vibration monitoring unit employing a high-precision, low-noise MEMS triaxial accelerometer, such as the ADXL355. This sensor connects to the MCU via an SPI or I2C digital interface and can synchronously output acceleration data in three mutually perpendicular directions (X, Y, and Z). The range and bandwidth can be configured as needed. It is rigidly mounted on the support 8, thus directly sensing the vibration transmitted from the idler shaft 3 bearing 2. A crucial implementation step is orientation calibration. Since the sensor is fixed to the idler shaft 3 along with the node module, its own X, Y, and Z axes are not naturally aligned with the physical directions (radial, axial, and tangential) of the idler. A conversion matrix between the sensor output and the physical direction must be established before or after installation, using known excitations or attitudes. For example, when the idler is stationary, the accelerometer is tilted using the gravity vector to determine the axial direction; when rotating at low speed, the centrifugal acceleration component is analyzed to determine the radial direction. Only after accurate calibration can the subsequent vibration spectrum and characteristic values ​​accurately reflect the radial runout, axial slippage, and other fault modes of the idler.

[0078] Temperature monitoring unit: The DS18B20 single-bus digital temperature sensor is selected. Its advantages are that it only requires one data line to communicate with the MCU, saving I / O resources; it has a wide temperature measurement range (-55°C ~ +125°C), which fully covers the downhole ambient temperature and bearing overheating range; and it has various packaging options, including TO-92 or stainless steel package with metal probe. The probe is tightly attached to the area of ​​the support 8 near the bearing housing 2 with thermal grease to accurately monitor the bearing temperature rise.

[0079] The sound monitoring unit consists of a microphone and an amplifier circuit. An electret microphone is used as the microphone, and its output signal is amplified by an operational amplifier based on the LM386 chip. The gain of the LM386 can be adjusted using a capacitor and potentiometer connected between pins 1 and 8. During debugging, the gain is adjusted to a suitable level by rotating the potentiometer, ensuring the amplitude of the normal operating sound falls within the middle of the MCU's ADC input range. After debugging, the potentiometer is sealed with insulating silicone to prevent resistance changes due to vibration. The amplified analog audio signal is then sampled at the MCU's ADC pin. By performing time-domain (e.g., RMS value) and frequency-domain (FFT spectrum) analysis on the sound signal, specific abnormal noises caused by roller scraping, missing rollers, etc., can be identified.

[0080] Battery voltage monitoring unit: Utilizing the high-precision 12-bit ADC inside the STM32F413, the terminal voltage of the energy storage battery 9 is sampled through a high-resistance resistor divider network (e.g., two 1MΩ resistors in series). The MCU has a stable reference voltage (e.g., 3.3V). By comparing the ADC reading with the reference voltage, the accurate battery voltage value can be calculated. This voltage is used to assess the system's state of energy and trigger an early warning when the voltage is too low.

[0081] In summary, all raw data from the sensors are periodically acquired by the MCU. The MCU's built-in program performs preliminary digital signal processing on the data, such as digitally filtering vibration and sound data to remove high-frequency noise and power frequency interference, calculating the effective value (RMS) of vibration acceleration, extracting temperature readings, and packaging these processed feature data into a specific data frame format, ready for transmission via the wireless network.

[0082] To ensure stable data transmission, the conformal antenna 6 device is a key design feature for solving the reliability problem of wireless communication under complex working conditions in mines.

[0083] The device consists of two parts: the antenna housing 7 and the antenna 6 encapsulated inside it. The antenna 6 itself can be a standard microstrip patch antenna 6, an inverted-F antenna 6 (IFA), or other miniaturized antenna 6 suitable for the 2.4 GHz ISM band (the common band for ZigBee).

[0084] The implementation steps strictly follow the sequence of machining and assembly: Machining the mounting groove: At the end of the roller shaft 3, select a location that will not affect the shaft strength and facilitates wiring (connecting the wireless sensor node 5 module). Using a CNC milling machine or precision lathe, mill a groove of a specific shape at this location, i.e., the mounting groove. The shape of this groove needs to be carefully designed, for example... Figures 1 to 3 The "key-shaped" (or "D-shaped") design shown prevents the antenna housing 7 from rotating within the slot. The depth, width, and length of the mounting slot must precisely match the external dimensions of the antenna housing 7, with strict tolerance control.

[0085] Fabrication of the antenna housing 7: The antenna housing 7 is integrally formed using additive manufacturing (3D printing) technology. The selected printing material must meet several requirements: First, it must have good electromagnetic wave penetration performance, i.e., low dielectric constant and small loss tangent, to ensure the radiation efficiency of the antenna 6; second, it must have good corrosion resistance to withstand the humid and weakly acidic environment underground; third, it must have a certain impact resistance to withstand accidental impacts from coal blocks and gangue. Commonly used materials include specially modified ABS, nylon (PA), or photosensitive resin.

[0086] Integration and Assembly: The antenna 6 is fixed to the pre-designed cavity within the antenna housing 7 using welding or connectors, and the feed line is led out. Then, the entire antenna housing 7 is embedded into the pre-machined mounting groove on the roller shaft 3. To ensure the integrity of the assembly, structural adhesive can be applied to the side of the housing before pressing it in. After assembly, the outer surface of the antenna housing 7 must be approximately flush with the outer circular surface of the roller shaft 3. Typically, the housing surface is designed to be slightly lower than the outer circular surface of the shaft by 0.2 to 0.5 mm. This small indentation prevents the antenna housing 7 from becoming a prominent wear point and facilitates the proper installation of the end metal shims during roller assembly (the shims press against the shaft end face around the housing, not against the housing itself).

[0087] In this way, the radiator of antenna 6 is essentially freed from the enclosed shielding cavity of the metal roller shell, allowing the signal to be effectively radiated from the open area at the shaft end. Simultaneously, the robust housing and embedded mounting provide excellent physical protection, ensuring that antenna 6 is no longer exposed to harsh environments. Even under coal dust covering conditions, nodes using this conformal antenna 6 design can maintain reliable communication within a 15-meter range. Furthermore, this invention fully meets the distance requirements for multi-hop transmission between nodes along the underground conveyor line.

[0088] After a detailed description of all the hardware modules mentioned above, we will now explain how these modules work together.

[0089] (I) Implementation process of adaptive speed regulation strategy.

[0090] The speed control strategy is a set of control algorithms running in the MCU of the wireless sensor node 5 module, which drives the H-bridge circuit in the energy management module 4.

[0091] Initialization and parameter loading (i.e., "determining the operating condition type of each idler roller"): Each smart idler roller is assigned a unique location number at the factory or during installation, and is bound to an operating condition type (smooth, uphill, downhill, turning). This "location-operating condition" mapping table can be sent out once via wireless network through the ground monitoring platform during system initialization and stored in the MCU's non-volatile memory (Flash). The MCU knows its own operating condition upon power-up.

[0092] The specific working steps are as follows: 1. Real-time data acquisition: Obtain the actual rotational speed of the idler roller: The MCU captures the zero-crossing pulse or specific waveform of the output voltage of the energy harvesting module 11 through its internal timer / counter peripheral, and accurately measures its pulse frequency. Combined with the known number of rotor pole pairs stored in the program, the actual rotational speed of the idler roller is calculated in real time.

[0093] Belt speed acquisition: The real-time rotational speed of the belt conveyor (usually referring to the belt linear speed, measured in m / s or m / min) is measured by the encoder of the drive unit or the main control system and broadcast via an upper-level network (such as industrial Ethernet), or periodically published by the system's coordinator node via a wireless network. The MCU receives this data wirelessly.

[0094] 2. Calculation and Decision: Calculate the target rotational speed .

[0095] 3. Calculation and Judgment of Deviation: Calculate the speed deviation. The MCU internally stores the speed regulation activation thresholds corresponding to different operating conditions. , , , For example, the allowable deviation is slightly larger under smooth operating conditions (). =3r / min), while the uplink operation requires closer following ( =1.5r / min). MCU judgment: If If the value exceeds the threshold for the current operating condition, an adjustment is triggered. Simultaneously, by comparison... and The size determines the direction of adjustment (acceleration or deceleration).

[0096] Specifically, the criteria for judging each working condition are as follows: Smooth working condition: when > At this time, routine fine-tuning of the idler rollers is required to correct the speed deviation between the idler rollers and the belt conveyor. The threshold value is for smooth operating conditions.

[0097] Upward operating condition: When > ( < When this happens, the idler rollers need to be adjusted for faster speed; if > If the idler roller is synchronized with the belt, no adjustment is needed. This is the threshold value under uplink operating conditions.

[0098] Downlink operating condition: When > ( < When this happens, the idler rollers need to be adjusted to reduce speed; if < If the idler roller is synchronized with the belt, no adjustment is needed. This is the threshold value under downlink conditions.

[0099] Turning condition: When > At this time, the idler rollers need to be adjusted in the corresponding direction, that is, the inner idler rollers are decelerated and the outer idler rollers are accelerated. This is the threshold value under turning conditions.

[0100] 4. Perform adjustment: Calculate adjustment time: After deciding to adjust, the MCU will calculate the required power-on time.

[0101] 5. Controlling H-bridge operation: The MCU outputs a corresponding control sequence to the H-bridge driver chip via its GPIO pins based on the adjustment direction. For example, acceleration outputs a signal that turns on Q1 and Q4, with a duration of [duration missing]. During this period, the system draws electrical energy from the energy storage battery 9 or instantaneous power generation to drive the stator coils to generate torque.

[0102] 6. Closed-loop feedback: After power-on, the MCU measures the new... Calculate the new If the deviation has been reduced to within the threshold, the adjustment ends; otherwise, a new round of adjustment will be started to form a closed-loop control until the idler speed and belt speed reach a coordinated state.

[0103] (II) Implementation process of networked cluster and adaptive monitoring.

[0104] Construction of a hierarchical wireless network: Thousands of intelligent idler nodes (wireless sensor nodes 5), along with routing nodes fixed along the conveyor tunnel walls or supports, and coordinator nodes deployed in the head or tail chambers, jointly form a hierarchical wireless network. This network adopts the ZigBee-Mesh network protocol. The coordinator node, as the network's central control unit, is responsible for initiating the network, allocating addresses, and authenticating network access requests. Routing nodes are responsible for relaying data and extending network coverage. All data collected by the idler nodes ultimately converges at the coordinator node. The coordinator node not only converges data but also coordinates data upload scheduling within the network. It can implement time-division or event-triggered scheduling strategies; for example, in non-emergency situations, it can sequentially query nodes in different segments to report data to avoid simultaneous large-scale uploads causing wireless channel congestion. Once an abnormal alarm (high-priority data) is received from a node, dedicated communication resources are immediately allocated to it to ensure timely upload of alarm information.

[0105] Node Adaptive Monitoring Strategy: Normal Mode (Time-Driven Polling): The MCU continuously checks the readings of the vibration sensor, temperature sensor, and battery voltage monitoring module. When all readings remain consistently stable within their respective preset normal threshold ranges (e.g., vibration acceleration RMS < 5 m / s², temperature < 70°C, battery voltage > 3.0V), the system considers the idler roller to be operating healthily. At this time, the node operates in time-driven polling mode. The MCU dynamically adjusts its duty cycle (i.e., the ratio of sleep time to working time) and the sensor data sampling frequency. The adjustment is based on the load status of the belt conveyor, which can be indirectly determined by its own rotational speed. Or the received belt speed The system uses a low duty cycle (e.g., 1%, meaning 99% of the time is spent in deep sleep) and a low sampling frequency (e.g., 1Hz) to determine the load. Under light load and low speed conditions, it switches to a high duty cycle (e.g., 10%) and a high sampling frequency (e.g., 10Hz or higher). This dynamic adjustment maximizes energy savings while ensuring basic monitoring continuity.

[0106] Anomaly Mode (Event-Driven Continuous Monitoring): If any of the vibration, temperature, or battery voltage data (e.g., a sudden spike in vibration amplitude to 15 m / s²) exceeds its corresponding preset normal threshold range, the MCU will immediately generate a hardware interrupt. The system instantly switches to event-driven continuous monitoring mode. In this mode, the MCU exits sleep mode and operates continuously (100% duty cycle), adjusting the sampling frequency of all relevant sensors to the maximum allowed by the hardware (e.g., accelerometer at full bandwidth, sampling rate ≥ 1 kHz). Simultaneously, it immediately attempts to establish a network connection and continuously and intensively reports high-priority data packets marked with "anomaly." This mode ensures that any sudden fault characteristics are captured and transmitted promptly without omission.

[0107] Through the complete exposition of the hardware structure and software strategy described above, those skilled in the art can clearly understand how the present invention, through a highly integrated hardware design combined with closely coordinated intelligent algorithms, systematically solves the four major problems raised in the background art: passive power supply, reliable communication, coordinated speed regulation, and cluster monitoring, thereby realizing the monitoring and proactive maintenance of the status of belt conveyor idler groups.

[0108] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A belt conveyor condition monitoring and speed control system based on intelligent idler groups, characterized in that, This includes wireless sensor nodes integrated and embedded inside the idler roller; The wireless sensor node includes an energy harvesting module, an energy management module, and a wireless sensor node module. The energy harvesting module is used to convert the mechanical energy of the rotating idler roller into alternating current; it includes a stator assembly and a rotor assembly; the stator assembly is fixed to the idler roller shaft, and the rotor assembly is fixed to the idler roller bearing housing; The energy management module is connected to the energy harvesting module and is used to manage the AC power and supply power to the wireless sensor node module; The energy management module includes an H-bridge circuit, which consists of four switching elements. The switching elements are controlled to turn on and off according to a preset adjustment strategy, and output positive or negative DC power. The output terminal of the H-bridge circuit is connected to the stator assembly of the energy harvesting module, and is used to supply positive or negative DC power to the stator assembly. The adjustment strategy includes the following steps: Determine the operating condition type of each idler roller based on the installation layout of the belt conveyor; The actual rotational speed of the idler rollers and the real-time rotational speed of the belt conveyor can be obtained in real time. Calculate the target speed of the idler roller based on the real-time rotational speed of the belt conveyor and the working condition type of the idler roller; Calculate the deviation between the actual rotational speed of the idler roller and the target rotational speed; If the deviation of the idler exceeds the speed regulation activation threshold corresponding to its operating condition type, directional DC current is supplied to the stator assembly of the energy harvesting module through the energy management module to adjust the idler speed. The direction of the directional DC current is determined according to the direction of the deviation and the operating condition type.

2. The belt conveyor status monitoring and speed control system based on intelligent idler groups according to claim 1, characterized in that, The energy management module also includes: A voltage conditioning circuit, electrically connected to the energy harvesting module, is used to convert the AC power output by the energy harvesting module into DC voltage. A charging management logic circuit, connected to an energy storage battery, is used to manage the charging and discharging of the energy storage battery.

3. The belt conveyor status monitoring and speed control system based on intelligent idler groups according to claim 1, characterized in that, The wireless sensor node module includes a low-power microcontroller, and a vibration sensor, a temperature sensor, and a sound sensor connected to the low-power microcontroller; wherein the vibration sensor, temperature sensor, and sound sensor are used to collect the status information of the idler roller.

4. The belt conveyor status monitoring and speed control system based on intelligent idler groups according to claim 1, characterized in that, It also includes conformal antenna devices; The conformal antenna device includes an antenna housing and an antenna disposed within the antenna housing; The end of the idler roller shaft is provided with a mounting groove; The antenna housing is embedded in the mounting slot, and the shape of the antenna housing is consistent with that of the mounting slot.

5. The belt conveyor status monitoring and speed control system based on intelligent idler groups according to claim 1, characterized in that, The formula for calculating the actual rotational speed is as follows: ； in, This refers to the actual rotational speed of the idler roller. The pulse frequency of the output voltage of the energy harvesting module. denoted as the number of pole pairs of the rotor permanent magnet.

6. The belt conveyor status monitoring and speed control system based on intelligent idler groups according to claim 1, characterized in that, Multiple wireless sensor nodes, along with routing nodes and coordinator nodes deployed along the belt conveyor, constitute a hierarchical wireless network. The coordinator node is used to coordinate data upload scheduling in the network according to the instructions of the adjustment strategy or the priority of monitoring data. The wireless sensor node module is configured to execute an adaptive monitoring strategy. When the data collected by the vibration sensor, temperature sensor and battery voltage monitoring module are within the corresponding preset normal threshold range, a time-driven polling mode is adopted, and the working duty cycle and data sampling frequency are dynamically adjusted according to the load status of the belt conveyor. When any of the vibration, temperature, or battery voltage data exceeds its corresponding preset normal threshold range, the system switches to event-driven continuous monitoring mode, adjusting the duty cycle and data sampling frequency to their maximum values.

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