A portable USB interface detection device

Abstract

The application discloses a portable USB interface detection device, and relates to the field of rail transit technology. The device adopts double-channel acquisition channels to realize parallel acquisition and synchronous transmission of mechanical performance and electrical performance detection signals, and designs an RC low-pass filtering, high-precision amplification, analog-digital conversion and exclusive operation whole-process signal processing scheme. Meanwhile, through highly integrated design and small-sized structure, and an independent battery power supply unit, the device is fully adapted to the mobile detection requirement in a train carriage. An operation and maintenance personnel only needs to perform one-time plug-in and plug-out operation to complete comprehensive and accurate detection of the interface, and the fault troubleshooting efficiency of the train on site is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of rail transit technology, specifically to a portable USB interface testing device. Background Technology

[0002] With the booming development of the rail transit industry, the quality of passenger service on passenger trains has been continuously improved. At the same time, the widespread use of consumer electronic products has made the demand for charging services during train travel increasingly urgent. To meet this demand, trains are equipped with various charging devices such as USB, Type-C, and power bank interfaces. These charging interfaces have become an indispensable basic service facility for trains, providing convenience for passengers to charge their electronic devices during their journey.

[0003] Currently, the USB interface testing methods used on trains have several shortcomings. First, the testing equipment is limited in function, separating mechanical and electrical performance testing. Maintenance personnel must use separate insertion / removal force testing and voltage testing equipment, requiring them to carry multiple tools and making the on-site testing process cumbersome and inefficient. Second, the existing insertion / removal force testing equipment lacks sufficient acquisition accuracy, making it difficult to accurately capture the minute mechanical forces during insertion and removal. For loosening issues caused by slight wear or deformation of the interface, these devices often fail to effectively diagnose the problem, leading to missed faults and impacting subsequent maintenance. Third, high-precision laboratory-grade testing equipment is bulky, heavy, and requires external power, making it unportable and unable to meet the needs of mobile testing within train carriages. Fourth, the signal processing of existing handheld testing equipment is simplistic, lacking targeted filtering, amplification, and precise calculation schemes. The connection between signal acquisition, transmission, and processing is not smooth enough, easily leading to signal interference and data calculation deviations, further reducing testing accuracy. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a portable USB interface testing device. It can achieve parallel acquisition and synchronous transmission of mechanical and electrical performance test signals by adopting dual acquisition channels. It has designed a complete signal processing scheme with RC low-pass filtering, high-precision amplification, analog-to-digital conversion and dedicated calculation. At the same time, through highly integrated design and miniaturized structure, as well as independent battery power supply unit, it is fully adapted to the mobile testing needs in train carriages. Maintenance personnel only need to perform a single plug-and-unplug operation to complete a comprehensive and accurate test of the interface, which greatly improves the efficiency of fault diagnosis on the train.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a portable USB interface detection device, the device comprising: a shell, a signal processing unit, a push-pull force sensor, a battery unit, a display unit, and a USB interface unit;

[0006] The outer shell adopts a portable design to meet the mobile detection needs of rail transit trains, while providing protection for each unit. The surface of the outer shell has corresponding button operation windows and display windows according to the needs of human-computer interaction and data reading.

[0007] The signal processing unit receives and processes the insertion and extraction force signal transmitted by the push-pull force sensor and the voltage signal transmitted by the USB interface unit, completes the signal calculation and conversion, and at the same time coordinates the power-on and power-off management, charging and discharging management and human-machine interaction operation of the device.

[0008] The push-pull force sensor realizes the acquisition of mechanical force and conversion of electrical signal during the plugging and unplugging of USB interface, and transmits the converted signal to the signal processing unit in real time.

[0009] The USB interface unit achieves precise plugging and unplugging adaptation with the USB female connector under test, transmits the mechanical force during the plugging and unplugging process to the push-pull force sensor, and at the same time collects the contact voltage signal of the interface under test and transmits it to the signal processing unit.

[0010] The battery unit provides a continuous and stable power supply;

[0011] The display unit receives the processed detection data output by the signal processing unit to synchronously display the USB interface insertion force, extraction force, and real-time voltage.

[0012] Furthermore, the signal processing unit receives the analog electrical signal of insertion / extraction force transmitted by the push-pull force sensor and the analog electrical signal of voltage sampling transmitted by the USB interface unit in real time through the built-in dual-channel signal acquisition channel. First, the two original analog signals are subjected to RC low-pass filtering to filter out high-frequency noise and electromagnetic interference signals introduced by the field environment and line transmission. Then, the two filtered signals are input to a high-precision low-drift operational amplifier. According to the original amplitude characteristics of the insertion / extraction force electrical signal and the voltage sampling signal, precise gain amplification adjustment is performed respectively to amplify the insertion / extraction force electrical signal to the 0-3.3V sampling range adapted to the MCU processor and amplify the voltage sampling signal to the signal amplitude range matched with the AD acquisition module of the MCU processor, ensuring the amplitude accuracy and consistency of the two types of signals.

[0013] Furthermore, the signal processing unit uses the MCU processor to perform AD conversion on the two signals after filtering and amplification, converting the analog electrical signals into calculable digital signals. For the insertion and extraction force digital signal output by the MCU processor, based on the linear calibration relationship between force and voltage corresponding to the 0-3kg acquisition range of the push-pull force sensor, linear calculation is performed using the insertion and extraction force value conversion linear calculation formula, combined with the force correction coefficient obtained from on-site calibration, to accurately convert the insertion and extraction force digital signal into specific values ​​of insertion and extraction force in kg. For the voltage sampling digital signal, according to the preset voltage division ratio coefficient of the voltage sampling circuit, reverse restoration calculation is performed using the reverse restoration formula of the actual voltage value of the USB interface, eliminating the signal amplitude attenuation caused by the voltage division of the sampling line, and converting the voltage digital signal into the actual voltage value of the USB interface in V. At the same time, according to the preset accuracy standard of the device, the accuracy of the two types of calculation results, namely insertion and extraction force and voltage, is rounded down to a specified number of decimal places, finally forming intuitive and identifiable detection data.

[0014] Furthermore, the signal processing unit performs linear calculations using a formula for converting insertion / extraction force values ​​into linear values, combined with a force correction coefficient obtained from on-site calibration. The formula is as follows: ,in, This is the actual value of the USB interface insertion / extraction force after conversion and expressed in kg. It is the real-time value of the insertion / extraction force digital signal acquired by the MCU processor; It is the digital reference value corresponding to the zero point of insertion and extraction force detection. This is the rated maximum sampling force value of the push-pull force sensor. This is the rated minimum sampling force value of the push-pull force sensor. yes The corresponding full-scale digital signal value of the insertion and extraction force; It is the force correction coefficient obtained from the on-site calibration of the push-pull force sensor.

[0015] Furthermore, the signal processing unit performs reverse restoration calculations based on the preset voltage division ratio coefficient of the voltage sampling circuit and the reverse restoration formula converted from the actual voltage value of the USB interface. The formula is as follows: ,in, This is the converted actual voltage value of the USB interface, expressed in volts (V). It is the real-time value of the voltage sampling digital signal acquired by the MCU processor; It is the rated reference voltage of the MCU processor's AD acquisition module. yes The corresponding full-scale digital signal value of the voltage sampled; It is the preset voltage division ratio coefficient of the voltage sampling circuit.

[0016] Furthermore, the signal processing unit manages the entire device operation process through a built-in MCU processor. Power-on / off control is achieved by receiving level signals triggered by buttons on the casing surface. Based on these signals, the MCU processor outputs power-on or power-off commands, controlling the push-pull force sensor, USB interface unit, and display unit to synchronously power on or power off. It also deeply integrates with the battery unit to manage the entire charging and discharging process. The MCU processor collects the battery unit's output voltage signal in real time, presets full-charge and low-charge voltage thresholds. When the battery voltage reaches the full-charge threshold, it immediately triggers a battery charging circuit cut-off command, stopping external charging. When the battery voltage falls below the low-charge threshold, it synchronously controls the display unit to output a low-charge warning indicator. It maintains a minimum stable power supply to the signal processing unit and the push-pull force sensor. In addition, the signal processing unit integrates an independent human-machine interaction module, which establishes a signal connection with the MCU processor through a dedicated button on the surface of the casing. The four preset operation commands correspond to the device power on / off, zeroing and calibration of the insertion and extraction force signal, switching of detection data units, and confirmation of detection results. Pressing the corresponding button will trigger the MCU processor to perform the corresponding operation. When the insertion and extraction force signal is zeroed and calibrated, the MCU processor will reset the force value acquisition reference of the push-pull force sensor to zero, eliminating the initial signal error caused by the device's own weight and component assembly gaps. The detection data unit switching can realize bidirectional switching between kg and N to adapt to different on-site detection standards. The detection result confirmation can lock the current detection data.

[0017] Furthermore, the push-pull force sensor is made primarily of stainless steel, with foil strain gauges attached to the surface of its alloy steel elastomer to form a Wheatstone bridge circuit. This circuit is connected to the rated power supply voltage, and the sensor as a whole is precisely adapted to the 0-3kg USB interface insertion and removal force acquisition range. When the USB interface unit transmits the mechanical force during the insertion and removal process to the alloy steel elastomer of the sensor without loss, the elastomer undergoes a corresponding slight elastic deformation according to the magnitude of the force, causing the foil strain gauge to deform synchronously and its resistance to change linearly with the mechanical force. This causes the Wheatstone bridge circuit to lose balance, and according to the force-to-electricity conversion formula, it outputs a weak analog electrical signal that is linearly corresponding to the magnitude of the insertion and removal mechanical force. The sensor then transmits this analog electrical signal to the corresponding acquisition channel of the signal processing unit in real time without delay through a dedicated signal cable led out from the side, thereby completing the accurate acquisition and electrical signal conversion of the mechanical force during the USB interface insertion and removal process.

[0018] Furthermore, the push-pull force sensor outputs a weak analog electrical signal that is linearly corresponding to the magnitude of the insertion and extraction mechanical force according to the force-to-electricity conversion formula, which is: ,in, It is a weak analog electrical signal voltage value output by the push-pull force sensor that corresponds linearly to the mechanical force of plugging and unplugging the USB interface. It is the overall sensitivity coefficient of the push-pull force sensor. It refers to the actual mechanical force that is transmitted losslessly from the USB interface unit to the sensor during the USB interface plugging and unplugging process. It is the rated supply voltage of the Wheatstone bridge circuit inside the sensor.

[0019] Furthermore, the USB interface unit adopts a standard USB male connector structure that is fully compatible with the specifications of the USB female connector to be tested on the train. The tail of the male connector is tightly fixed to the alloy steel elastomer of the push-pull force sensor through an integrated rigid connector. The connector is made of high-strength insulating material. The mechanical force generated during insertion and removal is directly transmitted to the force value acquisition end of the push-pull force sensor through the rigid connector without loss or delay. At the same time, two sets of high-precision elastic sampling contacts are integrated inside the male connector corresponding to the power contact position of the USB female connector to be tested. The sampling contacts and the small sampling resistor preset inside the male connector form a simple sampling circuit. When the male connector is plugged in and removed from the female connector to be tested, the sampling contacts are tightly attached to the power contacts of the female connector, and the contact voltage signal of the interface to be tested is collected in real time. After the collected voltage analog signal is initially regulated and noise reduced by the sampling circuit, it is transmitted to the corresponding signal acquisition channel of the signal processing unit through the shielded signal line.

[0020] Compared with existing technologies, this portable USB interface testing device has the following advantages:

[0021] This invention achieves simultaneous and accurate detection of mechanical and electrical performance through modular integration and collaborative design of functional units, along with a dedicated signal processing and computation scheme. This effectively solves the problems of limited functionality and low accuracy in existing testing equipment. Maintenance personnel can complete comprehensive and accurate interface testing with just one plug-and-play operation, significantly improving the efficiency of on-site fault diagnosis on trains. The push-pull force sensor's dedicated acquisition range and targeted signal processing unit can accurately capture minute mechanical forces and accurately reproduce actual voltage values, resulting in precise fault diagnosis. The device is highly integrated, small in size, lightweight, and independently powered by a battery. The human-machine interface module is simple to configure and easy to operate, with a low learning curve. Deep linkage between the battery unit and the signal processing unit enables overcharge and over-discharge protection. Combined with a protective casing and stable circuit design, the power supply is stable and the device has a long service life.

[0022] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0024] Figure 1 This is a structural block diagram of a portable USB interface testing device;

[0025] Figure 2 A flowchart of a portable USB interface testing device;

[0026] Figure 3 This is a flowchart of a signal processing unit for a portable USB interface detection device. Detailed Implementation

[0027] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0028] This invention provides a portable USB interface testing device, such as... Figure 1 As shown, it includes a housing, a signal processing unit, a push-pull force sensor, a battery unit, a display unit, and a USB interface unit. It achieves parallel acquisition and synchronous transmission of mechanical and electrical performance detection signals by adopting dual acquisition channels. It also features a complete signal processing scheme with RC low-pass filtering, high-precision amplification, analog-to-digital conversion, and dedicated computation. Furthermore, through highly integrated design and miniaturized structure, as well as an independent battery power supply unit, it is fully adapted to the mobile detection needs inside train carriages. Maintenance personnel only need to perform a single plug-and-play operation to complete a comprehensive and accurate test of the interface, which greatly improves the efficiency of fault diagnosis on the train.

[0029] The outer shell is primarily made of high-strength engineering plastic, with stainless steel edging reinforcing key load-bearing areas such as the grip and interface insertion points. This design balances lightweight portability with structural strength. The overall design features an ergonomic, integrated handheld structure with anti-slip rubber texture on the grip area, enhancing comfort and stability during on-site testing. The shell boasts an IP54 dust and water resistance rating, effectively resisting dust, moisture, and minor impacts and vibrations encountered in rail transit environments, adapting to complex working conditions. Internally, the shell incorporates integrated mounting slots and dedicated cable routing channels based on the structural dimensions and assembly requirements of each functional unit. Each unit is securely connected to the mounting slots using elastic clips and screws, preventing loosening or displacement of components due to equipment vibration during on-site testing. The wiring channel is equipped with wiring fixing clips, and the connecting wires between units are arranged in an orderly manner through the wiring channel, effectively preventing wire bending, wear, and detachment. At the same time, the inner wall of the wiring channel is insulated to avoid short circuits. The outer shell surface is designed according to the actual needs of human-machine interaction and test data reading, with corresponding button operation windows and display windows. The position of the button operation window corresponds one-to-one with the human-machine interaction buttons of the signal processing unit. The window is equipped with a waterproof and dustproof elastic button cover, which ensures normal button pressing operation and prevents dust and moisture from entering the equipment through the window. The display window is encapsulated with high light transmittance tempered glass, and a waterproof sealing ring is set at the encapsulation point. While ensuring clear reading of test data, it effectively protects the internal display unit and avoids damage to the display panel from external impacts.

[0030] The signal processing unit is the core control and data processing module of the device. It integrates dual independent signal acquisition channels, an MCU processor, an RC low-pass filter circuit, a high-precision low-drift operational amplifier circuit, a charge / discharge management module, and a human-machine interaction module. Each sub-module is soldered onto a multi-layer immersion gold printed circuit board. The circuit board layout is electromagnetically shielded to effectively reduce signal interference between modules. The overall design adopts a miniaturized integrated design to fit the portable layout requirements of the casing. The core function of the signal processing unit is to receive the insertion / extraction force analog electrical signal transmitted by the push-pull force sensor and the voltage sampling analog electrical signal transmitted by the USB interface unit, and to perform signal filtering, amplification, analog-to-digital conversion, and accurate calculation processing. At the same time, it coordinates the device's power-on / off management, intelligent management of the entire charging / discharging process, and human-machine interaction operation. Finally, it transmits the intuitive and accurate detection data after calculation to the display unit for synchronous display.

[0031] like Figure 2As shown, the signal processing unit receives analog electrical signals from the push-pull force sensor and the voltage sampling analog electrical signals from the USB interface unit in real time through built-in dual independent signal acquisition channels. The circuits of the two channels are completely independent, with no signal crosstalk, ensuring the independence and accuracy of signal acquisition. The two acquired raw analog electrical signals first enter their respective corresponding RC low-pass filter circuits for filtering. The RC low-pass filter circuit is composed of high-precision surface-mount resistors and capacitors in precise proportions. Its filtering cutoff frequency is precisely matched to the frequency range of high-frequency noise in the rail transit site, effectively filtering out electromagnetic interference signals generated by the operation of train equipment, high-frequency noise introduced during line transmission, and signal interference caused by equipment vibration. Only the effective characteristics of the two analog electrical signals are retained, avoiding interference signals from affecting the accuracy of subsequent data calculations. The two signals after RC low-pass filtering are synchronously input to a high-precision low-drift operational amplifier circuit for gain amplification and adjustment. The temperature drift coefficient of the operational amplifier circuit is controlled within microvolts per second. The circuit operates at the Celsius level, ensuring stable operation even under varying temperature conditions at rail transit sites. Based on the original amplitude characteristics of the insertion / extraction force electrical signal and the voltage sampling signal, independent gain adjustment branches are set up to precisely amplify the two signals. Specifically, the amplitude of the insertion / extraction force electrical signal is precisely adjusted to match the 0-3.3V sampling range of the MCU processor after amplification. The amplification value of the voltage sampling signal is matched and adjusted according to the signal receiving range of the MCU processor's AD acquisition module, ensuring that the amplified voltage signal amplitude perfectly matches the sampling requirements of the AD acquisition module. Ultimately, this guarantees the amplitude accuracy and consistency of both the insertion / extraction force and voltage signals, providing a stable and reliable signal foundation for subsequent analog-to-digital conversion.

[0032] The MCU processor performs high-resolution AD conversion on the two analog electrical signals after filtering and amplification, converting the continuous analog electrical signals into discrete digital signals that can be used for digital calculations. The sampling frequency of the analog-to-digital conversion is adapted to the normal operation speed of plugging and unplugging USB interfaces in the rail transit field, ensuring the real-time and continuous signal acquisition throughout the plugging and unplugging process, without data loss or ghosting.

[0033] For the digital insertion and extraction force signal after analog-to-digital conversion, the MCU processor, based on the linear calibration relationship between force and voltage corresponding to the 0-3kg acquisition range of the push-pull force sensor, performs linear calculations using the insertion and extraction force value conversion linear calculation formula, combined with the force correction coefficient obtained from on-site calibration, to accurately convert the digital insertion and extraction force signal into actual insertion and extraction force values ​​in kg. The calculation formula is as follows: ,in, The digital reference value corresponding to the zero point of insertion and extraction force detection is determined by zeroing and calibrating the equipment on-site. The rated maximum sampling force value (3kg) for the push-pull force sensor. The rated minimum sampling force value (0 kg) for the push-pull force sensor; for The corresponding full-scale digital signal value of the insertion and extraction force; The force correction coefficient is obtained through on-site calibration of the push-pull force sensor. It is acquired by on-site standard force value calibration and is used to eliminate calculation errors caused by the sensor's own accuracy, component assembly gaps, and the on-site environment, thereby improving the accuracy of force value detection.

[0034] For the digital voltage signal after analog-to-digital conversion, the MCU processor performs a reverse conversion operation based on the preset voltage division ratio of the voltage sampling circuit and the actual voltage value of the USB interface using the reverse conversion formula. This eliminates the signal amplitude attenuation caused by the voltage division in the sampling line, accurately converting the digital voltage signal into the actual voltage value of the USB interface in volts. The calculation formula is as follows: .in, This is the rated reference voltage for the MCU processor's AD acquisition module; for The corresponding full-scale digital signal value of the voltage sampled; This is the preset voltage division ratio coefficient of the voltage sampling circuit, which is determined by the voltage division resistor ratio of the voltage sampling circuit.

[0035] After the MCU processor completes the numerical calculations of insertion and extraction force and voltage, it performs precision rounding on the two types of calculation results according to the equipment's preset precision standards. Based on the industry precision requirements for USB interface testing in rail transit sites, it retains a specified number of decimal places, ultimately forming intuitive and identifiable digital test data that meets the metrological requirements of on-site testing.

[0036] The MCU processor establishes an electrical connection with the power button on the casing. Power on / off control is achieved by receiving high and low level signals triggered by the button. When the operator presses the power button, the MCU processor receives the corresponding level signal and immediately outputs a power-on or power-off command, controlling the push-pull force sensor, USB interface unit, and display unit to synchronously power on or power off, ensuring the coordinated start and stop of each unit and avoiding unnecessary power loss caused by independent operation of a single unit, thus improving the equipment's endurance. The charge / discharge management module is deeply integrated with the battery unit to achieve intelligent management of the entire battery charging and discharging process. The module has preset multi-level overcurrent protection thresholds and has four protection functions: overcharge, over-discharge, overcurrent, and short circuit. The MCU processor acquires the output voltage signal of the battery unit in real time through a dedicated acquisition port. At the same time, it presets the full charge voltage threshold and low charge voltage threshold according to the characteristics of the battery cell. When the battery voltage reaches the full charge threshold, the MCU processor immediately triggers the battery charging circuit cut-off command to disconnect the external charging line from the battery unit, thereby achieving overcharge protection. When the battery voltage is detected to be lower than the low charge voltage threshold, the MCU processor synchronously controls the display unit to output a low charge reminder, and at the same time controls the device to automatically enter a low power operation mode, maintaining only the minimum stable power supply to the signal processing unit and push-pull force sensor to ensure the normal implementation of the core detection function until the device is charged or shut down.

[0037] The signal processing unit integrates an independent human-machine interface module, which establishes a signal connection with the MCU processor through dedicated touch buttons on the outer shell. All buttons have mechanical tactile feedback, making it convenient for testing personnel to confirm the validity of the operation. The module has a total of 4 preset independent operation commands, corresponding to equipment power on / off, zeroing and calibration of insertion and extraction force signals, switching of test data units, and confirmation of test results. Each button trigger transmits a unique level signal to the MCU processor, realizing accurate recognition and execution of commands.

[0038] When the insertion and extraction force signal is zeroed and calibrated, the MCU processor receives the corresponding instruction and quickly resets the force value acquisition reference of the push-pull force sensor to zero. This operation can be completed with one click under any working condition on site without additional tooling. It can effectively eliminate the initial signal error caused by the equipment's own gravity and component assembly gaps, and ensure the zero-point accuracy of the insertion and extraction force detection.

[0039] The test data unit switching function can realize bidirectional switching between the insertion and extraction force test units of kg and N. The MCU processor has a built-in high-precision unit conversion coefficient. After receiving the switching command, it automatically completes the unit conversion of the value to adapt to different test standards and measurement requirements in the rail transit field.

[0040] Once the test result confirmation function is triggered, the MCU processor locks the current insertion / extraction force and voltage test data, and temporarily stores the locked data in the MCU's built-in storage module. This allows testers to view and record the data later, preventing changes in the test data due to subsequent misoperations and ensuring the accuracy of the recorded test data.

[0041] The push-pull force sensor is the core of the device for acquiring mechanical force. The main body is made of stainless steel, with the core force-bearing component being an alloy steel elastomer. This elastomer undergoes a tempering heat treatment process to ensure the stability of its elastic modulus and fatigue resistance. The sensor's acquisition range is precisely adapted to the actual needs of USB interface insertion and removal force detection, with a fixed setting of 0-3kg. The stress-sensitive area of ​​the alloy steel elastomer is covered with professional strain adhesive and fitted with foil strain gauges. These foil strain gauges are assembled into a Wheatstone bridge circuit using a full-bridge mounting method. The strain gauge surface is covered with a moisture-proof insulating coating to improve the sensor's environmental adaptability. A precision zero-adjustment potentiometer is built into the Wheatstone bridge circuit, enabling precise zeroing for initial circuit balance. This circuit is connected to a stable rated power supply voltage, ensuring the balance stability of the bridge circuit and the accuracy of the output signal.

[0042] The alloy steel elastomer of the push-pull force sensor is tightly fixed to the rigid connector of the USB interface unit via a fastening structure. When the USB interface unit transmits the mechanical force during the insertion and removal process to the alloy steel elastomer without loss, the elastomer undergoes a corresponding minute elastic deformation according to the magnitude of the force. This deformation is elastic and can be completely restored after the force disappears, avoiding plastic deformation of the elastomer that would affect the detection accuracy. The deformation of the alloy steel elastomer causes the foil strain gauge attached to its surface to deform synchronously, causing the resistance of the foil strain gauge to change linearly with the mechanical force. This disrupts the initial equilibrium state of the Wheatstone bridge circuit. The circuit outputs a weak analog electrical signal that corresponds linearly to the magnitude of the insertion and removal mechanical force according to the force-to-electricity conversion formula. The force-to-electricity conversion formula is: ,in, The overall sensitivity coefficient of the push-pull force sensor is determined by both the sensor's structural design and the performance parameters of the foil strain gauge. This is the rated supply voltage value for the Wheatstone bridge circuit inside the sensor.

[0043] A dedicated shielded signal cable is led out from the side of the push-pull force sensor. The cable adopts a double-layer metal braided shielding design to effectively resist electromagnetic interference at the rail transit site. The cable establishes a solid electrical connection with the insertion and extraction force signal acquisition channel of the signal processing unit, and transmits the weak analog electrical signal output by the Wheatstone bridge circuit to the signal processing unit in real time without delay or loss, thereby completing the accurate acquisition of mechanical force and electrical signal conversion during the USB interface insertion and extraction process.

[0044] The USB interface unit is an adapter connection component between the device and the USB female connector under test. It adopts a standard USB male connector structure that is fully compatible with the specifications of the USB female connector under test in the rail transit train. The contact springs of the male connector are gold-plated to improve conductivity and wear resistance, ensuring accurate insertion and removal adaptation with the female connector under test and long-term reliability. The tail of the USB male connector has an integrally molded rigid connector. This connector is made of glass fiber reinforced epoxy resin, which has both good structural rigidity and electrical insulation performance. The end of the rigid connector away from the USB male connector is tightly fixed to the alloy steel elastomer of the push-pull force sensor by thread fastening and anaerobic adhesive to prevent loosening. This allows the mechanical force generated by the USB interface unit during insertion and removal to be directly transmitted to the force value acquisition end of the push-pull force sensor without loss or delay through the rigid connector, ensuring the accuracy of mechanical force acquisition.

[0045] Inside the USB male connector, at the location corresponding to the power contacts of the USB female connector under test, two sets of high-precision elastic sampling contacts are integrated. These contacts are made of a highly conductive, elastic metal material with a gold-plated surface to enhance conductivity, wear resistance, and oxidation resistance. They possess excellent elastic recovery performance, ensuring a tight and stable contact between the sampling contacts and the power contacts of the female connector during insertion and removal, avoiding voltage signal acquisition errors caused by poor contact. The sampling contacts, together with the high-precision, low-temperature drift surface-mount sampling resistor pre-installed inside the USB male connector, form a simple voltage sampling circuit. This circuit includes a series surface-mount Zener diode and a parallel high-frequency ceramic filter capacitor, providing preliminary voltage stabilization and noise reduction functions. This allows for preliminary processing of the acquired voltage signal, effectively reducing signal fluctuations and interference, and improving the stability of the voltage signal acquisition.

[0046] After the USB male connector is plugged in and out of the female connector under test, the sampling circuit acquires the analog voltage signal of the contact point of the interface under test in real time. After preliminary voltage regulation and noise reduction, the analog voltage signal is transmitted to the voltage signal acquisition channel of the signal processing unit through the shielded signal line to complete the acquisition and stable transmission of the voltage signal.

[0047] The battery unit provides a continuous and stable power supply to all functional units of the equipment. It uses a high-capacity lithium polymer battery pack as the core energy storage component. This battery pack has no memory effect, a long charge and discharge cycle life, and is suitable for the endurance requirements of mobile testing on site. The battery unit integrates a battery protection module and a voltage regulation output module. The whole unit has a miniaturized sealed package structure, which is suitable for the portable design requirements of the equipment.

[0048] The battery protection module is equipped with a protection chip with a microsecond-level response, featuring four protection functions: overcharge, over-discharge, overcurrent, and short circuit. This effectively extends battery life and ensures the safety of battery power supply. The voltage regulation output module adopts a synchronous rectification buck circuit design, which has high power conversion efficiency and can effectively reduce power supply loss. This module uses a voltage regulation circuit to accurately convert the battery's output voltage into a stable rated voltage that meets the operating requirements of each unit, including the casing, signal processing unit, push-pull force sensor, display unit, and USB interface unit, ensuring that each unit operates stably and reliably within its rated voltage range.

[0049] The battery unit establishes a bidirectional electrical connection with the signal processing unit's charge / discharge management module. This connection provides stable power to the signal processing unit and other units while simultaneously transmitting battery voltage and current signals to the signal processing unit in real time, enabling intelligent charge / discharge management. The battery unit also features a pre-installed Type-C external charging port on the side of its casing, with a waterproof and dustproof cover. This facilitates fast charging on-site while preventing dust and moisture from entering. The charging port supports universal fast charging protocols, effectively shortening charging time and improving the equipment's on-site efficiency.

[0050] The display unit and the MCU processor of the signal processing unit establish an electrical connection through a stable serial communication method. This allows for real-time, zero-delay reception of the processed and rounded detection data output by the MCU processor, enabling synchronous dynamic display of USB interface insertion force, extraction force, and real-time voltage. The display unit uses a miniaturized high-definition segment LCD panel, combining low power consumption with high display clarity. The panel is equipped with energy-saving LED backlighting, which supports automatic light-sensing brightness adjustment. This ensures clear and legible detection data under various lighting conditions, including strong and weak light, while effectively reducing backlight power consumption and extending equipment battery life.

[0051] The display unit's interface features a modular design with separate areas for insertion / extraction force display, voltage display, unit identification, and device status identification. The insertion / extraction force display area simultaneously shows real-time values ​​of insertion and extraction forces, as well as dynamic force changes throughout the insertion / extraction process. The unit identification area automatically updates with changes in the unit of the test data. The device status identification area clearly displays the device's operating status, such as low battery, data lock, zeroing / calibration, and charging, allowing on-site testing personnel to quickly and intuitively read test data and understand the device's operating status. The display unit's operating voltage is provided by the battery unit after voltage regulation and is synchronized with other units in the device via a signal processing unit. When the device enters a low-power operating mode, the display unit's backlight brightness automatically adjusts to the minimum to further reduce power consumption and ensure the continuous operation of the device's core testing functions.

[0052] like Figure 3As shown, the specific testing workflow of the portable USB interface testing device provided by this invention at the rail transit train site is as follows:

[0053] Equipment Power-On and Zeroing Calibration: The testing personnel hold the equipment and press the power button on the surface of the casing. After receiving the level signal, the MCU processor of the signal processing unit immediately outputs a power-on command, controlling the push-pull force sensor, USB interface unit, and display unit to power on and start synchronously. The display unit enters standby mode. Then, the testing personnel press the insertion and extraction force signal zeroing calibration button. The MCU processor quickly resets the force value acquisition reference of the push-pull force sensor to zero, eliminating the initial signal error caused by the equipment's own weight and component assembly gaps, completing the preparation work before testing. This zeroing operation can be completed under any working conditions on site without additional debugging.

[0054] Interface insertion / removal and signal acquisition: The testing personnel hold the device and perform normal insertion / removal operations between the standard USB male connector of the USB interface unit and the USB female connector under test on the rail transit train. During the insertion / removal process, the USB interface unit transmits the mechanical force to the push-pull force sensor without loss. The push-pull force sensor collects the mechanical force in real time and converts it into a weak insertion / removal force analog electrical signal through force-to-electricity conversion. This signal is then transmitted to the signal processing unit in real time via a shielded signal cable. At the same time, the elastic sampling contact of the USB interface unit is in close contact with the power contact of the female connector under test, collecting the contact voltage analog electrical signal of the interface under test. After preliminary voltage stabilization and noise reduction by the sampling circuit, the signal is transmitted to the signal processing unit, realizing the synchronous and real-time acquisition of insertion / removal force and voltage signals.

[0055] Signal processing and data computation: The dual signal acquisition channels of the signal processing unit receive analog electrical signals of insertion and extraction force and voltage respectively. After passing through RC low-pass filtering and high-precision low-drift amplification, the MCU processor performs high-resolution AD conversion to convert the analog electrical signals into digital signals. The MCU processor performs accurate numerical calculations on the two types of signals through the numerical conversion formula of insertion and extraction force and the reverse restoration formula of voltage value, and performs rounding processing according to the preset accuracy standard to obtain intuitive test data that meets the requirements of on-site measurement.

[0056] Data Display and Human-Computer Interaction: The signal processing unit transmits the processed detection data to the display unit in real time. The display unit synchronously displays the insertion force, extraction force, and real-time voltage values ​​through a partitioned interface, and can also display the dynamic changes in force and voltage throughout the entire insertion and extraction process. According to the on-site testing standards and metrological requirements, the testing personnel can press the unit switching button to switch between the insertion and extraction force units of kg and N, and the unit label area is updated synchronously. After the test is completed, the testing personnel press the test result confirmation button, and the MCU processor immediately locks the current test data and temporarily stores it to prevent subsequent misoperations from causing data changes, making it convenient for the testing personnel to record accurately.

[0057] Equipment shutdown and subsequent processing: After the testing personnel record the locked test data of the display unit, they press the power button again. The MCU processor outputs a power-off command to control each functional unit to shut down synchronously, completing a complete USB interface test process. If multiple USB interfaces need to be tested continuously, the next interface can be plugged in or unplugged directly without repeated zeroing. The equipment will automatically collect and process the new test data.

[0058] Throughout the testing process, the MCU processor of the signal processing unit continuously acquires the output voltage and current signals of the battery unit in real time. When the battery voltage is detected to be lower than the low charge threshold, it immediately controls the display unit to output a low charge reminder, prompting the testing personnel to charge the equipment in time. If the equipment is connected to an external charging line during the testing process, the MCU processor will automatically cut off the charging circuit when it detects that the battery voltage has reached the full charge threshold, realizing the overcharge protection of the battery. At the same time, the display unit will display a charging completion indicator to ensure the safety of battery use.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A portable USB interface testing device, characterized in that, The device includes: a housing, a signal processing unit, a push-pull force sensor, a battery unit, a display unit, and a USB interface unit; The outer shell adopts a portable design to meet the mobile detection needs of rail transit trains, while providing protection for each unit. The surface of the outer shell has corresponding button operation windows and display windows according to the needs of human-computer interaction and data reading. The signal processing unit receives and processes the insertion and extraction force signal transmitted by the push-pull force sensor and the voltage signal transmitted by the USB interface unit, completes the signal calculation and conversion, and at the same time coordinates the power-on and power-off management, charging and discharging management and human-machine interaction operation of the device. The push-pull force sensor realizes the acquisition of mechanical force and conversion of electrical signal during the plugging and unplugging of USB interface, and transmits the converted signal to the signal processing unit in real time. The USB interface unit achieves precise plugging and unplugging adaptation with the USB female connector under test, transmits the mechanical force during the plugging and unplugging process to the push-pull force sensor, and at the same time collects the contact voltage signal of the interface under test and transmits it to the signal processing unit. The battery unit provides a continuous and stable power supply; The display unit receives the processed detection data output by the signal processing unit to synchronously display the USB interface insertion force, extraction force, and real-time voltage.

2. The portable USB interface testing device according to claim 1, characterized in that, The signal processing unit receives, in real time, the analog electrical signal of insertion / extraction force transmitted by the push-pull force sensor and the analog electrical signal of voltage sampling transmitted by the USB interface unit through the built-in dual-channel signal acquisition. First, the two original analog signals are subjected to RC low-pass filtering to filter out high-frequency noise and electromagnetic interference signals introduced by the field environment and line transmission. Then, the two filtered signals are input to a high-precision, low-drift operational amplifier. According to the original amplitude characteristics of the insertion / extraction force electrical signal and the voltage sampling signal, precise gain amplification adjustment is performed respectively. The insertion / extraction force electrical signal is amplified to the 0-3.3V sampling range adapted to the MCU processor, and the voltage sampling signal is amplified to the signal amplitude range matched with the AD acquisition module of the MCU processor, ensuring the amplitude accuracy and consistency of the two types of signals.

3. The portable USB interface testing device according to claim 1, characterized in that, The signal processing unit uses an MCU processor to perform AD conversion on the two signals after filtering and amplification, converting the analog electrical signals into calculable digital signals. For the insertion and extraction force digital signal output by the MCU processor, based on the linear calibration relationship between force and voltage corresponding to the 0-3kg acquisition range of the push-pull force sensor, a linear calculation formula for the insertion and extraction force value is used, combined with the force correction coefficient obtained from on-site calibration, to accurately convert the insertion and extraction force digital signal into specific values ​​of insertion and extraction force in kg. For the voltage sampling digital signal, according to the preset voltage division ratio coefficient of the voltage sampling circuit, a reverse restoration calculation is performed using the reverse restoration formula for the actual voltage value of the USB interface, eliminating the signal amplitude attenuation caused by the voltage division of the sampling line, and converting the voltage digital signal into the actual voltage value of the USB interface in V. At the same time, according to the preset accuracy standard of the device, the accuracy of the two types of calculation results, namely insertion and extraction force and voltage, is rounded down to a specified number of decimal places, finally forming intuitive and identifiable detection data.

4. The portable USB interface testing device according to claim 3, characterized in that, The signal processing unit performs linear calculations by converting the insertion / extraction force values ​​into linear calculations, combined with force correction coefficients obtained from on-site calibration. The formula is as follows: ,in, This is the actual value of the USB interface insertion / extraction force after conversion and expressed in kg. It is the real-time value of the insertion / extraction force digital signal acquired by the MCU processor; It is the digital reference value corresponding to the zero point of insertion and extraction force detection. This is the rated maximum sampling force value of the push-pull force sensor. This is the rated minimum sampling force value of the push-pull force sensor. yes The corresponding full-scale digital signal value of the insertion and extraction force; It is the force correction coefficient obtained from the on-site calibration of the push-pull force sensor.

5. A portable USB interface testing device according to claim 3, characterized in that, The signal processing unit performs reverse restoration calculations based on the preset voltage division ratio coefficient of the voltage sampling circuit and the reverse restoration formula converted from the actual voltage value of the USB interface. The formula is as follows: ,in, This is the converted actual voltage value of the USB interface, expressed in volts (V). It is the real-time value of the voltage sampling digital signal acquired by the MCU processor; It is the rated reference voltage of the MCU processor's AD acquisition module. yes The corresponding full-scale digital signal value of the voltage sampled; It is the preset voltage division ratio coefficient of the voltage sampling circuit.

6. A portable USB interface testing device according to claim 1, characterized in that, The signal processing unit manages the entire device operation process through a built-in MCU processor. Power on / off control is achieved by receiving level signals triggered by buttons on the casing surface. Based on these signals, the MCU processor outputs power-on or power-off commands, controlling the push-pull force sensor, USB interface unit, and display unit to synchronously power on or power off. Furthermore, it deeply integrates with the battery unit to manage the entire charging and discharging process. The MCU processor collects the battery unit's output voltage signal in real time, presets full-charge and low-charge voltage thresholds. When the battery voltage reaches the full-charge threshold, it immediately triggers a battery charging circuit cut-off command, stopping external charging. When the battery voltage falls below the low-charge threshold, it synchronously controls the display unit to output a low-charge warning indicator and maintains... The system provides a minimum stable power supply to the signal processing unit and push-pull force sensor. In addition, the signal processing unit integrates an independent human-machine interface module, which establishes a signal connection with the MCU processor through a dedicated button on the surface of the housing. The four preset operation commands correspond to power on / off, zeroing and calibrating the insertion and extraction force signal, switching the detection data unit, and confirming the detection result. Pressing the corresponding button will trigger the MCU processor to perform the corresponding operation. When the insertion and extraction force signal is zeroed and calibrated, the MCU processor will reset the force value acquisition reference of the push-pull force sensor to zero, eliminating the initial signal error caused by the device's own weight and component assembly gaps. The detection data unit switching can achieve bidirectional switching between kg and N to adapt to different on-site detection standards. The detection result confirmation can lock the current detection data.

7. A portable USB interface testing device according to claim 1, characterized in that, The push-pull force sensor is made primarily of stainless steel, with foil strain gauges attached to the surface of its alloy steel elastomer to form a Wheatstone bridge circuit. This circuit is connected to the rated power supply voltage, and the sensor as a whole is precisely adapted to the 0-3kg USB interface insertion and removal force acquisition range. When the USB interface unit transmits the mechanical force during the insertion and removal process to the alloy steel elastomer of the sensor without loss, the elastomer undergoes a corresponding slight elastic deformation according to the magnitude of the force. This causes the foil strain gauge to deform synchronously, resulting in a change in its resistance that is linearly related to the mechanical force. Consequently, the Wheatstone bridge circuit becomes unbalanced and outputs a weak analog electrical signal that is linearly corresponding to the magnitude of the insertion and removal mechanical force according to the force-to-electricity conversion formula. The sensor then transmits this analog electrical signal to the corresponding acquisition channel of the signal processing unit in real time without delay through a dedicated signal cable led out from the side, thereby completing the accurate acquisition and electrical signal conversion of the mechanical force during the USB interface insertion and removal process.

8. A portable USB interface testing device according to claim 7, characterized in that, The push-pull force sensor outputs a weak analog electrical signal that is linearly corresponding to the magnitude of the insertion and extraction mechanical force according to the force-to-electricity conversion formula, which is: ,in, It is a weak analog electrical signal voltage value output by the push-pull force sensor that corresponds linearly to the mechanical force of plugging and unplugging the USB interface. It is the overall sensitivity coefficient of the push-pull force sensor. It refers to the actual mechanical force that is transmitted losslessly from the USB interface unit to the sensor during the USB interface plugging and unplugging process. It is the rated supply voltage of the Wheatstone bridge circuit inside the sensor.

9. A portable USB interface testing device according to claim 1, characterized in that, The USB interface unit adopts a standard USB male connector structure that is fully compatible with the specifications of the USB female connector to be tested on the train. The tail of the male connector is tightly fixed to the alloy steel elastomer of the push-pull force sensor through an integrated rigid connector. The connector is made of high-strength insulating material. The mechanical force generated during insertion and removal is directly transmitted to the force value acquisition end of the push-pull force sensor through the rigid connector without loss or delay. At the same time, two sets of high-precision elastic sampling contacts are integrated inside the male connector corresponding to the power contact position of the USB female connector to be tested. The sampling contacts and the small sampling resistor preset inside the male connector form a simple sampling circuit. When the male connector is plugged in and removed from the female connector to be tested, the sampling contacts are tightly attached to the power contacts of the female connector, and the contact voltage signal of the interface to be tested is collected in real time. After the collected voltage analog signal is initially regulated and noise reduced by the sampling circuit, it is transmitted to the corresponding signal acquisition channel of the signal processing unit through the shielded signal line.

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