Inspection robot vibration signal detection device based on wireless transmission

Abstract

The application discloses a wireless transmission-based inspection robot vibration signal detection device and belongs to the technical field of instruments and meters, comprising a piezoelectric vibration sensor, a power supply circuit, a signal acquisition and processing system and a wireless transmission module; the power supply circuit is connected with the piezoelectric vibration sensor, the signal acquisition and processing system and the wireless transmission module respectively; the piezoelectric vibration sensor is arranged at the front end of the signal acquisition and processing system; and the wireless transmission module is arranged at the rear end of the signal acquisition and processing system. The wireless transmission-based inspection robot vibration signal detection device is adopted, the device adopts a centralized acquisition architecture, can synchronously process 8 vibration signals, the wireless transmission distance is not less than 3 km, the overall structure is lightweight, complex wiring is not needed, and the device is suitable for the load and operation requirements of a fly-away inspection robot.

Description

Technical Field

[0001] This invention relates to the field of instrumentation technology, and in particular to a vibration signal detection device for inspection robots based on wireless transmission. Background Technology

[0002] Flying inspection robots are used for inspecting high-voltage power lines. During their flight and line movement, they are subject to continuous or momentary vibrations due to the combined effects of their own propulsion system, external airflow, and mechanical structure. During the transition between aerial flight and line movement, the flexible constraints of the power lines can cause the robot to tilt and experience vibration overload. These effects are multifaceted. The robot's frame, motors, reducers, propellers, and connecting components are susceptible to fatigue damage from prolonged vibration loads, and this damage can accumulate with each flight, creating a vicious cycle. Therefore, real-time measurement of the vibration signals from flying inspection robots is necessary to promptly address any abnormal vibration conditions.

[0003] With the continuous advancement of instrumentation and sensor technology, vibration measurement has been widely applied to the monitoring, control, prediction, and fault identification of critical mechanical equipment, greatly improving the efficiency and reliability of such equipment. Traditional vibration measurement typically uses vibration sensors paired with dedicated vibration measurement systems, transmitting signals via cables. Due to cable length limitations in the placement of measurement points, long-distance measurements are difficult to achieve. While existing wireless vibration measurement solutions can eliminate cable constraints, the signal conditioning circuitry and wireless transmission module are integrated into a single sensor, resulting in a significant sensor weight. In scenarios with strict weight requirements, this limits the measurement to single-point vibration, making it unsuitable. Flying inspection robots, operating at heights, need to simultaneously measure vibration signals at multiple locations (such as the bases of the four arms, the geometric center of the fuselage, and the gimbal camera mounting base). Their effective payload is very limited; therefore, traditional wired vibration detection methods and conventional wireless vibration sensors are insufficient to meet the practical needs of their high-altitude mobile operations. Summary of the Invention

[0004] The purpose of this invention is to provide a vibration signal detection device for inspection robots based on wireless transmission. The device adopts a centralized acquisition architecture, can process 8 vibration signals simultaneously, has a wireless transmission distance of not less than 3km, has a lightweight overall structure, does not require complex wiring, and is suitable for the load and operation requirements of flying inspection robots.

[0005] To achieve the above objectives, the present invention provides a vibration signal detection device for an inspection robot based on wireless transmission, comprising a piezoelectric vibration sensor, a power supply circuit, a signal acquisition and processing system, and a wireless transmission module; the power supply circuit is connected to the piezoelectric vibration sensor, the signal acquisition and processing system, and the wireless transmission module respectively, providing stable power to each module; The piezoelectric vibration sensor is located at the front end of the signal acquisition and processing system to convert vibration signals into electrical signals. The signal acquisition and processing system includes a preamplifier circuit, a low-pass filter circuit, an AD conversion circuit, and an MCU control circuit connected in sequence. The signal acquisition and processing system can simultaneously access and process up to 8 piezoelectric vibration sensor signals. The wireless transmission module is located at the back end of the signal acquisition and processing system and is connected to the MCU control circuit to realize long-distance wireless transmission of vibration data.

[0006] Preferably, the piezoelectric vibration sensor includes a base and a housing fixedly mounted on the base, the housing having mounting holes; the base serves as the mounting base for the piezoelectric vibration sensor, with a central column integrally formed with the base at its center, providing a radial positioning reference for the piezoelectric material and the mass block; the piezoelectric material is fitted around the central column, its upper and lower end faces electrically isolated from other parts by insulating pads, the lower end supported on the upper surface of the base, and the inner wall of the mass block tightly fitted with the outer cylindrical surface of the central column, achieving radial positioning and axial support; the mass block has a split ring structure, encircling the piezoelectric material, its inner sidewall tightly fitted with the outer side of the piezoelectric material, its lower end face supported on the upper surface of the base, and its upper end face provided with axial preload by a fastening ring, pressing the piezoelectric material firmly onto the central column. To ensure no relative displacement between the three components under vibration conditions, a fastening ring is fitted around the top of the outer periphery of the mass block. This ring is an annular component used to provide axial preload to the piezoelectric material and the mass block, ensuring tight fit between the components. The upper surface of the fastening ring forms a mounting platform to support the built-in circuit. The built-in circuit integrates a charge amplifier. The input terminal of the built-in circuit is electrically connected to the electrodes of the piezoelectric material via leads, converting the high internal resistance charge signal generated by the piezoelectric material under inertial force into a low internal resistance voltage signal. The output terminal of the built-in circuit is electrically connected to the inner end of a signal terminal. The signal terminal is fixedly installed in a mounting hole on the housing and connected to the output terminal of the built-in circuit. The outer end of the signal terminal extends out of the housing for connection to an external signal acquisition and processing system.

[0007] Preferably, the housing and base are made of stainless steel; the piezoelectric material is piezoelectric ceramic, which uses the positive piezoelectric effect to convert mechanical deformation into charge signal; the mass block is made of tungsten alloy to increase inertial force and improve signal output; the built-in circuit integrates a charge amplifier and a buffer to convert high internal resistance charge signal into low internal resistance voltage signal; the fastening ring is used to press the internal components to ensure that the structure of each layer fits tightly, realizing the signal conversion link of "acceleration → inertial force → piezoelectric deformation → charge output".

[0008] Preferably, the power supply circuit includes a power interface, a power switch, a multi-channel power conversion module, and status indicator lights. The multi-channel power conversion module includes a 5V power module, a 2.5V power module, a -5V power module, a ±9V power module, and a 3.3V power module. The power interface is directly connected to the 12V power supply of the inspection robot. The multi-channel power conversion module generates 5V, 3.3V, 2.5V, -5V power and ±9V bipolar power. Status indicator lights are installed on each of the multi-channel regulated power supplies to enable rapid fault location.

[0009] Preferably, the preamplifier circuit adopts an instrumentation amplifier chip plus voltage follower structure, and differentially connects to the piezoelectric vibration sensor signal to achieve high common-mode rejection ratio and low-noise amplification; the input impedance of the voltage follower is not less than 10Ω. 12 Ω is used to isolate the impedance between the preceding and following stages to avoid signal distortion. The amplification factor can be flexibly adjusted through the feedback resistor.

[0010] Preferably, the low-pass filter circuit adopts an 8th-order Butterworth integrated switched capacitor filter, which has low passband ripple and high attenuation slope, and can effectively suppress electromagnetic interference and sensor resonance noise. The cutoff frequency is set by the microcontroller crystal oscillator circuit. In this device, it is set to 3kHz to ensure that effective signals within 2kHz pass through without attenuation. The high-frequency noise suppression depth is not less than 48dB, thus avoiding sampling aliasing from the hardware level.

[0011] Preferably, the AD conversion circuit uses an ADC device with 8-channel synchronous sampling, 16-bit resolution, and 200kSPS sampling rate, supports ±5V / ±10V range configuration, and integrates a data latch internally, enabling synchronous acquisition and time-division reading of 8-channel signals; the analog input wiring adopts 50Ω impedance control, is kept away from digital signal lines, and reduces electromagnetic coupling interference.

[0012] Preferably, the MCU control circuit serves as the core of data processing and scheduling. Upstream, it communicates with the AD conversion circuit to complete multi-channel data DMA reception, buffering, and hardware filtering; downstream, it connects to the wireless transmission module to implement data protocol encapsulation and transmission. The power-on reset and manual reset circuits of the MCU control circuit employ a 10kΩ pull-up resistor and parallel capacitor structure to ensure that the low-level duration of the power-on reset is not less than 20ms. The microcontroller crystal oscillator circuit uses a 24MHz crystal oscillator with a 22pF load capacitor connected in parallel across its ends. The PCB wiring distance is controlled within 5mm to reduce the influence of parasitic parameters. The program programming port adopts a standard 5-pin design, corresponding to VCC, GND, RESET, SWDIO, and SWCLK, which are directly connected to the corresponding I / O ports of the microcontroller for downloading, updating, and debugging the microcontroller program, balancing practicality and convenience. The programmable pin definitions are clear. The VCC pin maintains the same power supply voltage as the microcontroller to ensure stable power supply during programming. The GND pin shares a common ground with the entire control circuit to reduce interference and ensure the accuracy of programming signal transmission. The SWDIO and SWCLK pins employ anti-interference design, minimizing their wiring length and maintaining a distance of at least 3mm from the microcontroller crystal oscillator circuit wiring to avoid signal crosstalk. The RESET pin is directly connected to the microcontroller's reset pin and is used to control the microcontroller's reset during programming.

[0013] The MCU adopts a time-sharing strategy of DMA background reception plus TIM2 timer interrupt, combined with hardware FPU to accelerate convolution operation, to realize time-sharing cyclic calculation of 8-channel data, avoid main program blocking, and improve system real-time performance.

[0014] Preferably, the wireless transmission module uses a Sub-GHz radio frequency chip, supports LoRa spread spectrum communication, and has a wireless transmission distance of not less than 3km. It adopts a dual-antenna diversity reception design, a configuration impedance matching network and LC power supply filtering. The module communicates with the MCU through the SPI interface and uses the BUSY pin to achieve timing synchronization. It has low power consumption, high sensitivity and strong anti-interference characteristics, and can meet the stable transmission requirements in high-altitude mobile scenarios.

[0015] According to the specific embodiments provided by the invention, the present invention discloses the following technical effects: (1) The signal acquisition and processing system of the present invention can simultaneously access and process 8 vibration sensor signals, realize synchronous detection of vibration signals at multiple key positions of the flying inspection robot, and meet the vibration monitoring requirements of the whole machine.

[0016] (2) The present invention adopts a centralized acquisition architecture, abandons the redundant structure of traditional distributed sensors, greatly reduces the weight of the device, and adapts to the strict load limits of flying inspection robots.

[0017] (3) The present invention uses LoRa spread spectrum communication, with a transmission distance of not less than 3km, freeing it from the constraints of wired wiring and adapting it to high-altitude mobile operation scenarios.

[0018] (4) The device of the present invention has a simple structure, requires no complicated wiring and debugging, is easy to install and operate, and is highly practical.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] Figure 1 This is a perspective view of the piezoelectric vibration sensor structure of an embodiment of the inspection robot vibration signal detection device based on wireless transmission according to the present invention; Figure 2 This is a schematic diagram of the power circuit of an embodiment of the vibration signal detection device for an inspection robot based on wireless transmission according to the present invention. Figure 3 This is a schematic diagram of the preamplifier circuit of the signal acquisition and processing system of the inspection robot vibration signal detection device based on wireless transmission according to an embodiment of the present invention. Figure 4 This is a schematic diagram of the low-pass filter circuit of the signal acquisition and processing system of the inspection robot vibration signal detection device based on wireless transmission according to an embodiment of the present invention. Figure 5 This is a schematic diagram of the AD conversion circuit of the signal acquisition and processing system of the inspection robot vibration signal detection device based on wireless transmission according to an embodiment of the present invention. Figure 6 This is a schematic diagram of the MCU control circuit of the signal acquisition and processing system of the inspection robot vibration signal detection device based on wireless transmission according to an embodiment of the present invention. Figure 7 This is a schematic diagram of the wireless transmission module circuit of an embodiment of the vibration signal detection device for an inspection robot based on wireless transmission according to the present invention.

[0021] Figure Labels 31. Housing; 32. Internal Circuit; 33. Signal Terminal; 34. Fastening Ring; 35. Base; 36. Mass Block; 37. Piezoelectric Material; 38. Center Column; 1. Power Switch; 2. 5V Power Module; 3. 2.5V Power Module; 4. -5V Power Module; 5. 9V Power Indicator; 6. ±9V Power Module; 7. 5V Power Indicator; 8. 3.3V Power Indicator; 9. 2.5V Indicator; 10. 3.3V Power Module; 11. Power Interface; 12. Signal Input Negative Terminal; 13. Instrument Amplifier 14. Voltage Follower; 15. Signal Input Positive Terminal; 16. Preamplifier Feedback Resistor; 17. Cutoff Frequency Clock Capacitor; 18. Integrated Low-Pass Filter; 19. Voltage Buffer; 20. AD Conversion Chip; 21. Analog Signal Input Terminal; 22. Power-On Reset and Manual Reset Circuit; 23. Microcontroller Crystal Oscillator Circuit; 24. Microcontroller; 25. Programming Port; 26. Wireless Transmission Chip Crystal Oscillator Circuit; 27. Sub-GHz High-Speed ​​Antenna; 28. 2.4GHz Antenna; 29. ​​Wireless Transmission Chip. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] Example 1 like Figures 1-7 As shown, the present invention discloses a vibration signal detection device for an inspection robot based on wireless transmission, comprising: a piezoelectric vibration sensor, a power supply circuit, a signal acquisition and processing system, and a wireless transmission module. The power supply circuit is connected to the piezoelectric vibration sensor, the signal acquisition and processing system, and the wireless transmission module respectively, and is used to provide stable power supply to each module.

[0025] like Figure 1As shown, the piezoelectric vibration sensor is mainly used to convert vibration signals into small electrical signals. It includes a base 35 and a housing 31 fixedly mounted on the base 35. The housing 31 has mounting holes. The base 35 is the mounting base for the piezoelectric vibration sensor. A central column 38 integrally formed with the base 35 is provided at its center to provide a radial positioning reference for the piezoelectric material 37 and the mass block 36.

[0026] The piezoelectric material 37 is fitted around the central column 38. Its upper and lower end faces are electrically isolated from other parts by insulating pads. The lower end is supported on the upper surface of the base 35. The inner wall of the inner hole is tightly fitted with the outer cylindrical surface of the central column 38 to achieve radial positioning and axial support. The mass block 36 has a split ring structure and is fitted around the piezoelectric material. Its inner side wall is tightly fitted with the outer side of the piezoelectric material 37. The lower end face is supported on the upper surface of the base 35. The upper end face is provided with axial preload by the fastening ring 34, which presses the piezoelectric material 37 tightly onto the central column 38 to ensure that the three have no relative displacement under vibration conditions.

[0027] A fastening ring 34 is fitted on the top of the outer periphery of the mass block 36. The fastening ring 34 is a ring-shaped component used to provide axial preload for the piezoelectric material 37 and the mass block 36, ensuring that the components of each layer are tightly fitted. The upper end face of the fastening ring 34 forms a mounting platform for supporting the built-in circuit 32. The built-in circuit 32 integrates a charge amplifier. The input terminal of the built-in circuit 32 is electrically connected to the electrode of the piezoelectric material 37 through a lead wire, converting the high internal resistance charge signal generated by the piezoelectric material 37 under the action of inertial force into a low internal resistance voltage signal. The output terminal of the built-in circuit 32 is electrically connected to the inner end of the signal terminal 33. The signal terminal 33 is fixedly installed in the mounting hole opened on the housing 31, and the signal terminal 33 is connected to the output terminal of the built-in circuit 32. The outer end of the signal terminal 33 extends out of the housing 31 for connection with an external signal acquisition and processing system.

[0028] The housing 31 and the base 35 are made of stainless steel. The lower end of the housing 31 and the base 35 are sealed and fixed by laser welding to form a closed protective cavity, which encloses the built-in circuit 32, fastening ring 34, mass block 36, piezoelectric material 37 and central column 38 inside. The piezoelectric material 37 is a piezoelectric ceramic. Under the action of inertial force, the piezoelectric ceramic undergoes mechanical deformation and generates equal and opposite bound charges on the two electrode surfaces through the positive piezoelectric effect. The mass block 36 is made of high-density tungsten alloy material. It amplifies the vibration signal through inertial force to ensure that the piezoelectric material 37 generates a detectable charge signal.

[0029] The built-in circuit 32 integrates a charge amplifier and a buffer, converting the high internal resistance charge signal generated by the piezoelectric material 37 into a low internal resistance voltage signal, which is then connected to the signal terminal 33. The signal terminal 33 then connects to the preamplifier circuit of the signal acquisition and processing system. The fastening ring 34 secures the piezoelectric material 37 and the mass block 36, ensuring a tight fit between the layers. The entire signal chain achieves signal sensing through a four-stage transformation: acceleration → inertial force → piezoelectric deformation → charge output.

[0030] Figure 2 The power circuits for each module primarily convert the 12V power supplied by the flying inspection robot into the 2.5V, 5V, -5V, 9V, and -9V power supplies required by subsequent circuits. Power interface 11 is designed to be compatible with the existing power supply structure on the flying inspection robot and connects directly to the robot's 12V power supply. Power switch 1 is a toggle switch used to power on and off the entire device. The multi-channel power conversion module includes a 5V power module 2, a 2.5V power module 3, a -5V power module 4, a 3.3V power module 10, and a ±9V power module 6. The 5V power modules 2, 2.5V power modules 3, and 3.3V power modules 10 all use the AMS1117 power chip to convert 12V power to 5V, 2.5V, and 3.3V respectively. The -5V power module 4 uses the L7905 power chip to convert -9V power to -5V. The ±9V power module 6 uses the TPS65131 power chip to convert 5V voltage to a ±9V dual-voltage power supply. Each multi-channel power conversion module is equipped with indicator lights of different colors, including a 9V power indicator light 5, a 5V power indicator light 7, a 3.3V power indicator light 8, and a 2.5V indicator light 9, to facilitate quick identification of the specific fault location in the event of a power failure. The above multi-channel power conversion modules are used for the piezoelectric vibration sensor, preamplifier circuit, low-pass filter circuit, AD conversion circuit, MCU control circuit and wireless transmission module of the wireless vibration detection device.

[0031] Figure 3 The preamplifier circuit of the signal acquisition and processing system employs a high-precision instrumentation amplifier chip 13. Its main function is to amplify the signal output from the piezoelectric vibration sensor without loss, and then transmit it to the next stage circuit via a voltage follower 14. The preamplifier circuit determines the upper limit of the signal-to-noise ratio in the signal link; if the first stage introduces too much noise and distortion, subsequent circuits cannot eliminate it. The upstream piezoelectric vibration sensor simply processes the charge signal into a measurable small voltage signal, which contains common-mode noise and power supply interference. Therefore, the preamplifier circuit uses the instrumentation amplifier chip 13 and the voltage follower 14 to ensure that the signal from the vibration sensor is extracted as losslessly as possible without distortion, and to suppress noise interference. The voltage follower 14 has a gain of 1 and an input impedance ≥10Ω.12 The Ω impedance avoids signal distortion caused by the weak load-carrying capacity of the front-end piezoelectric vibration sensor, while the low output impedance stably drives the subsequent gain adjustment circuit. Its core function is to achieve high impedance isolation, eliminating impedance mismatch between the signal source and the subsequent circuit. The positive input terminal 15 is connected to the signal output terminal of the piezoelectric vibration sensor, and the negative input terminal 12 is connected to the sensor ground, forming a differential input. In this embodiment, the positive input terminal 15 and the negative input terminal 12 use BNC connectors. The signal amplification factor is adjusted by the preamplifier feedback resistor 16 to meet the needs of the subsequent low-pass filter circuit.

[0032] Figure 4 This low-pass filter circuit in the signal acquisition and processing system filters out high-frequency noise (such as electromagnetic interference and sensor resonance noise) during dynamic signal acquisition, achieving high-frequency noise suppression and impedance matching to avoid ADC sampling aliasing. The preamplifier circuit and low-pass filter circuit consist of eight identical independent circuits, facilitating the processing of signals from eight sensors simultaneously. The low-pass filter circuit's function is to filter out high-frequency noise (such as electromagnetic interference and sensor resonance noise) during dynamic signal acquisition, preventing ADC sampling aliasing. This design uses a combination circuit of an integrated low-pass filter 18 and a voltage buffer 19 to achieve high-frequency noise suppression and impedance matching. The integrated low-pass filter 18 is an 8th-order Butterworth switched-capacitor low-pass filter with a passband ripple ≤0.1dB and a transition band attenuation slope of up to 48dB / octave, far superior to the 20dB / octave of ordinary RC low-pass filters. It has extremely strong high-frequency signal suppression capabilities. Utilizing switched-capacitor filtering technology, it eliminates the need for numerous external resistors and capacitors, matching the weight requirements of the flying inspection robot. The biggest advantage of this circuit is that the cutoff frequency is set solely by the microcontroller's crystal oscillator circuit 23. Therefore, the cutoff frequency can be easily and precisely changed by the clock capacitor 17. In this example, based on the structure and purpose of the flying inspection robot, the cutoff frequency is set to 3kHz. This ensures that effective signals below 2kHz pass through without attenuation, while attenuating high-frequency noise above 3kHz by ≥48dB, thus completely avoiding aliasing at the hardware level.

[0033] Figure 5This is the AD conversion circuit for the signal acquisition and processing system. The AD converter is the core hub connecting analog and digital signals, and it needs to achieve synchronous acquisition of 8 channels of vibration signals, high-precision quantization, and interface adaptation with the MCU control circuit. The voltage buffer 19 connects the signal to the analog signal input terminal 21. In this example, the AD conversion chip 20 uses an 8-channel synchronous sampling, 16-bit resolution, and 200kSPS sampling rate ADC device. The range can be configured to ±5V or ±10V via the RANGE pin to adapt to input signals of different amplitudes. The internal latch can temporarily store 8 channels of converted digital signals, and time-division reading is achieved through control signals such as RD and CS to avoid data conflicts between channels. The control logic circuit's reset (RESET), range configuration (RANGE), and sampling trigger (START) functions are controlled by the subsequent MCU circuit. At the same time, the analog input traces are controlled with a 50Ω impedance, kept away from digital signal lines and power lines to avoid electromagnetic coupling interference; the trace length is ≤15cm to reduce parasitic capacitance and inductance.

[0034] Figure 6The MCU control circuit of the signal acquisition and processing system is mainly responsible for synchronous reception, buffering, data calculation, and high-precision filtering of multi-channel digital signals. Downstream, it connects to the wireless transmission module to achieve protocol encapsulation and reliable transmission of data. As the core hub for data flow and functional coordination, the MCU control circuit interfaces upstream with the AD conversion circuit to perform synchronous reception, buffering, and high-precision filtering of multi-channel digital signals. Downstream, it connects to the wireless transmission module to achieve protocol encapsulation and reliable long-distance transmission of acquired data. The NRST pin of the microcontroller 24 is connected to a 3.3V power supply through a 10kΩ pull-up resistor, and a reset capacitor is connected in parallel to analog ground, forming the power-on reset and manual reset circuit 22. Upon power-on, the reset capacitor charges through the pull-up resistor, and the NRST pin remains low for at least 20ms, ensuring reliable power-on reset and system initialization of the microcontroller 24. Manual reset is achieved using a tactile button. One end of the button is connected to the NRST pin, and the other end is grounded. When the button is pressed, the pin is pulled low, triggering the reset. The parallel capacitor effectively eliminates button mechanical bounce, improving the stability and reliability of the reset operation. In this embodiment, the microcontroller crystal oscillator circuit 23 uses a 24MHz crystal oscillator circuit, with 22pF load capacitors connected in parallel to ground at both ends of the crystal oscillator to match the microcontroller clock input impedance. During PCB routing, the distance between the crystal oscillator and the microcontroller clock input pin is strictly controlled within 5mm. By shortening the routing length, parasitic capacitance and signal interference are reduced, ensuring the stability of the clock signal. The program programming port 25 adopts a standard 5-pin design, corresponding to VCC, GND, RESET, SWDIO, and SWCLK, respectively. It is directly connected to the corresponding I / O port of the microcontroller 24 to realize the download, update, and debugging of the microcontroller 24 program, taking into account both practicality and convenience. The programmable port 25 has clearly defined pins. The VCC pin maintains the same power supply voltage as the microcontroller 24 to ensure stable power supply during programming. The GND pin shares a common ground with the entire control circuit to reduce interference and ensure the accuracy of programming signal transmission. The SWDIO and SWCLK pins employ anti-interference design, minimizing their wiring length and maintaining a distance of at least 3mm from the microcontroller crystal oscillator circuit 23 to avoid signal crosstalk. The RESET pin is directly connected to the reset pin of the microcontroller 24 for controlling the microcontroller 24's reset during programming.

[0035] The microcontroller software development process is divided into four stages: parameter design, coefficient generation, program implementation, and real-time optimization. It fully utilizes the MCU's built-in floating-point unit (FPU) and DMA data transfer mechanism to improve signal processing efficiency and data throughput. To avoid blocking the main program execution during digital filtering calculations, the system adopts a scheduling strategy of "DMA reception + timer interrupt time-sharing": the DMA controller handles the background reception and buffering of multi-channel data from the AD module, while the main program processes one set of downsampled data per round; the 8 channels use a time-sharing cyclic calculation mechanism, automatically switching to the next channel after processing a single channel. The entire time-sharing scheduling process is triggered by the TIM2 timer interrupt, preventing excessively long single calculation times from causing system response delays. By enabling the hardware FPU to accelerate convolution operations in the filtering algorithm, the computation time is significantly reduced, and the system's real-time performance is greatly improved, meeting the high-speed acquisition and processing requirements of multi-channel vibration signals from the flying inspection robot.

[0036] Figure 7 This is a wireless transmission module circuit, whose main function is to transmit the data processed by the microcontroller 24 to a remote receiving end. It solves the problem of real-time measurement of vibration signals from flying inspection robots operating at heights.

[0037] In this embodiment, the crystal oscillator circuit 26 of the wireless transmission chip uses a passive crystal oscillator as the clock source. A 22pF load capacitor is connected in parallel to ground at each end of the crystal oscillator. The RF front-end features a dual-antenna diversity reception design with a Sub-GHz high-speed antenna 27 and a 2.4GHz antenna 28. The two RF signals are connected to the chip's RFO_HP and RFIO_HF pins via a π-type matching network. An external antenna is connected to the end of the matching network via an SMB interface, which improves signal reception sensitivity and anti-interference capability. The power supply uses an LC filter network and a 104 decoupling capacitor to effectively suppress power supply noise and ensure stable operation of the RF chip. The wireless transmission chip 29 communicates with the MCU using the standard SPI protocol, with data exchange achieved through the LR_NSS, LR_SCK, LR_MOSI, and LR_MISO pins. The LR_BUSY pin indicates the chip's operating status, facilitating reliable timing control by the MCU. The wireless transmission module fully leverages the advantages of LoRa spread spectrum communication, ensuring long-distance transmission of over 3km while possessing strong anti-interference capabilities and low power consumption. It is well-suited to the lightweight and long-endurance requirements of flying inspection robots, achieving stable and reliable transmission of vibration signals. The data receiver and transmitter employ the same design for point-to-point transmission, ensuring both stable data transmission and data security.

[0038] Working principle: The base 35 of the piezoelectric sensor is rigidly connected to the part of the flying inspection robot where vibration needs to be measured. The signal terminal 33 of the piezoelectric sensor is connected to the signal input BNC terminal of the signal acquisition and processing system through a shielded wire. The signal acquisition and processing module is installed on the frame of the flying inspection robot and fixed with bolts. The 12V power supply of the flying inspection robot is connected to the power interface 11, and the power switch 1 is turned on. The wireless transmission module is plugged into the signal acquisition and processing module through a mounting bracket. The wireless receiving module is connected to the PC through a serial port. Depending on the transmission distance and transmission rate requirements, either Sub-GHz mode or 2.4GHz mode transmission can be selected. Simultaneously, either the Sub-GHz high-speed antenna 27 or the 2.4GHz antenna 28 is installed according to the selection.

[0039] When the flying inspection robot is in flight, the piezoelectric vibration sensor detects the vibration signal and converts it into a small voltage signal. After amplification, filtering, AD conversion, and MCU control by the signal acquisition and processing system, the signal is finally transmitted to the receiving end by the wireless transmission module. The receiving end is connected to serial port debugging tools such as Jcom, which can directly read the vibration value and observe the vibration waveform at low frequencies.

[0040] Therefore, the present invention adopts the above-mentioned vibration signal detection device for inspection robots based on wireless transmission. The device adopts a centralized acquisition architecture, can process 8 vibration signals simultaneously, has a wireless transmission distance of not less than 3km, has a lightweight overall structure, does not require complex wiring, and is suitable for the load and operation requirements of flying inspection robots.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. 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 still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A vibration signal detection device for an inspection robot based on wireless transmission, characterized in that: It includes a piezoelectric vibration sensor, a power supply circuit, a signal acquisition and processing system, and a wireless transmission module; the power supply circuit is connected to the piezoelectric vibration sensor, the signal acquisition and processing system, and the wireless transmission module respectively; The piezoelectric vibration sensor is located at the front end of the signal acquisition and processing system to convert vibration signals into electrical signals. The signal acquisition and processing system includes a preamplifier circuit, a low-pass filter circuit, an AD conversion circuit, and an MCU control circuit connected in sequence. The signal acquisition and processing system can simultaneously access and process up to 8 piezoelectric vibration sensor signals. The wireless transmission module is located at the back end of the signal acquisition and processing system and is connected to the MCU control circuit to realize long-distance wireless transmission of vibration data.

2. The vibration signal detection device for an inspection robot based on wireless transmission according to claim 1, characterized in that: The piezoelectric vibration sensor includes a base and a housing fixedly mounted on the base. The housing has mounting holes. A central column is integrally formed on the base, and a piezoelectric material is sleeved around the outer periphery of the central column. The lower end of the piezoelectric material is connected to the upper surface of the base, and the inner wall of the piezoelectric material is tightly fitted to the outer cylindrical surface of the central column. A mass block is wrapped around the outer periphery of the piezoelectric material, and the inner sidewall of the mass block is tightly fitted to the outer sidewall of the piezoelectric material. The lower end of the mass block is connected to the support on the upper surface of the base. A fastening ring is fitted on the top of the outer periphery of the mass block. The fastening ring is used to secure the piezoelectric material and the mass block. The gauge block provides axial preload to ensure a tight fit. A built-in circuit is installed on the top of the fastening ring. This built-in circuit integrates a charge amplifier. The input terminal of the built-in circuit is electrically connected to the electrodes of the piezoelectric material via leads, converting the high internal resistance charge signal generated by the piezoelectric material under inertial force into a low internal resistance voltage signal. The output terminal of the built-in circuit is electrically connected to the inner end of a signal terminal. The signal terminal is fixedly installed in a mounting hole on the housing and connected to the output terminal of the built-in circuit. The outer end of the signal terminal extends out of the housing for connection to an external signal acquisition and processing system.

3. The vibration signal detection device for an inspection robot based on wireless transmission according to claim 2, characterized in that: The shell and base are made of stainless steel; the piezoelectric material is piezoelectric ceramic; and the mass block is made of tungsten alloy.

4. The vibration signal detection device for an inspection robot based on wireless transmission according to claim 1, characterized in that: The power supply circuit includes a power interface, a power switch, a multi-channel power conversion module, and status indicator lights. The multi-channel power conversion module includes a 5V power module, a 2.5V power module, a -5V power module, a ±9V power module, and a 3.3V power module. The multi-channel power conversion module is used to convert an external 12V power supply into multiple regulated power supplies that can be used by the piezoelectric vibration sensor, the signal acquisition and processing system, and the wireless transmission module. Each of the multiple regulated power supplies is equipped with a status indicator light to enable rapid fault location.

5. The vibration signal detection device for an inspection robot based on wireless transmission according to claim 1, characterized in that: The preamplifier circuit includes a negative signal input terminal, an instrumentation amplifier chip, a voltage follower, a positive signal input terminal, and a preamplifier feedback resistor. The negative signal input terminal, the positive signal input terminal, and the preamplifier feedback resistor are all connected to the instrumentation amplifier chip, which is connected to the voltage follower. The preamplifier circuit employs an instrumentation amplifier chip plus voltage follower structure to differentially input the piezoelectric vibration sensor signal. The voltage follower's input impedance is not less than 10Ω. 12 Ω, the amplification factor is adjusted by the feedback resistor of the preamplifier to achieve high impedance isolation and low noise amplification.

6. The vibration signal detection device for an inspection robot based on wireless transmission according to claim 1, characterized in that: The low-pass filter circuit includes a cutoff frequency clock capacitor, an integrated low-pass filter, and a voltage buffer. The cutoff frequency clock capacitor is connected to the integrated low-pass filter, and the integrated low-pass filter is connected to the voltage buffer. The low-pass filter circuit uses an 8th-order Butterworth integrated switched-capacitor filter with a cutoff frequency set to 3kHz to ensure that effective signals within 2kHz pass through without attenuation, and the high-frequency noise suppression depth is not less than 48dB.

7. The vibration signal detection device for an inspection robot based on wireless transmission according to claim 1, characterized in that: The AD conversion circuit includes an AD conversion chip with an analog signal input terminal connected to it. The AD conversion circuit uses an ADC device with 8-channel synchronous sampling, 16-bit resolution, and 200kSPS sampling rate, and supports ±5V / ±10V range configuration. The analog input wiring adopts 50Ω impedance control and is kept away from digital signal lines to reduce electromagnetic interference.

8. The vibration signal detection device for an inspection robot based on wireless transmission according to claim 1, characterized in that: The MCU control circuit includes a power-on reset and manual reset circuit, a microcontroller crystal oscillator circuit, a microcontroller, and a programming port. The microcontroller is connected to the power-on reset and manual reset circuit, the programming port, and the microcontroller crystal oscillator circuit. The power-on reset and manual reset circuit of the MCU control circuit adopts a 10kΩ pull-up resistor and parallel capacitor structure. The microcontroller crystal oscillator circuit uses a 24MHz crystal oscillator, with a 22pF load capacitor connected in parallel across its two ends. The PCB wiring distance is controlled within 5mm. The programming port adopts a 5-pin design and is directly connected to the corresponding I / O port of the microcontroller. The MCU adopts a time-sharing strategy of DMA background reception plus TIM2 timer interrupt, combined with hardware FPU to accelerate convolution operation, to realize time-sharing cyclic calculation of 8-channel data, avoid main program blocking, and improve system real-time performance.

9. The vibration signal detection device for an inspection robot based on wireless transmission according to claim 1, characterized in that: The wireless transmission module includes a wireless transmission chip crystal oscillator circuit, a Sub-GHz high-speed antenna, a 2.4GHz antenna, and a wireless transmission chip. The wireless transmission chip is connected to the wireless transmission chip crystal oscillator circuit, the Sub-GHz high-speed antenna, and the 2.4GHz antenna, respectively. The wireless transmission module uses a Sub-GHz radio frequency chip, supports LoRa spread spectrum communication, employs dual-antenna diversity reception and a π-type impedance matching network, and communicates with the MCU via an SPI interface. Timing synchronization is achieved using the BUSY pin, and the wireless transmission distance is no less than 3km.

Images