Apparatus and method for sensing and acquiring data - Patents.com

Abstract

The present invention relates to a data sensing and acquisition apparatus, the data sensing and acquisition apparatus comprising a first sensing and transducer module configured to sense and acquire a first strain signal, a second sensing and transducer module configured to sense and acquire a second strain signal, and a data acquisition module arranged in signal or data communication with the first sensing and transducer module and the second sensing and transducer module, the data acquisition module comprising a selector configured to select between receiving the first strain signal or the second strain signal and to convert the received first strain signal or the received second strain signal to a digital value.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to data acquisition devices and methods for sensing and acquiring data, particularly but not exclusively, strain data. [Background technology]

[0002] Various sensors, such as fiber Bragg grating (FBG) sensors, are employed for structural health monitoring (SHM) in civil, mechanical, and / or marine engineering applications. Fiber Bragg grating FBG sensors are optical sensors that are interrogated using one or more spectrometers to receive recorded wavelength shifts and data as a function of applied strain. The spectral / wavelength shifts can then be correlated to changes in intensity, allowing users to convert the light intensity into an analog voltage. This allows for the use of relatively low-cost electronic components in systems employing fiber Bragg grating FBG sensors.

[0003] Another type of sensor used in structural health monitoring (SHM) is the electrical strain gauge (ESG). Electrical strain gauge ESGs may be deployed in dry locations to measure mechanical strain and are relatively reliable. Electrical strain gauge ESGs can be interrogated with several types of conventional equipment and data acquisition systems.

[0004] Currently, fiber Bragg grating sensors and electrical strain gauges (ESGs) are separately positioned and interrogated using optical and electrical devices to obtain tensile or compressive strain measurements. A typical data acquisition system (DAQ) for acquiring strain measurements may include either fiber Bragg grating sensors or electrical strain gauges (ESGs) arranged to communicate the measurements to a laptop for display. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Chinese Patent Application Publication No. 112613129 Summary of the Invention [Problem to be solved by the invention]

[0006] Structures requiring multiple measurements require the deployment of multiple data acquisition systems (DAQs). This can increase the components and cost of acquiring strain measurements in various civil, mechanical, and / or marine engineering applications. Additionally, the collected measurements may be of various data types and often require further processing before the measurements can be viewed by the user. This further processing may require additional components.

[0007] There is a need to provide a solution that reduces the cost and form factor associated with sensing and acquiring data, particularly soiling measurements and data. [Means for solving the problem]

[0008] A technical solution is proposed in the form of an integrated data acquisition device, in which electrical strain gauge ESG and fiber Bragg grating FBG sensors can be integrated into a single device. The electrical strain gauge ESG sensors and fiber Bragg grating FBG sensors can form part of a sensing and transducer module, such that the converted signals are standardized in digitized differential voltage form to facilitate display on a computer device. The integrated data acquisition device can form part of a complete system-in-box, from sensor measurement to data transfer.

[0009] According to one aspect of the present disclosure, there is provided an apparatus for sensing and acquiring strain data, the apparatus including: a first sensing and transducer module configured to sense and acquire a first strain signal; a second sensing and transducer module configured to sense and acquire a second strain signal; and a data acquisition module arranged in signal or data communication with the first sensing and transducer module and the second sensing and transducer module. The data acquisition module includes a selector configured to select between receiving the first strain signal and receiving the second strain signal and to convert the received first strain signal or the received second strain signal to a digital value.

[0010] In an embodiment, the first sensing and transducer module comprises an electrical strain gauge acquisition unit having an electrical foil strain gauge sensor. In an embodiment, the first sensing and transducer module comprises a Wheatstone bridge circuit, the electric foil strain gauge sensors forming arms of the Wheatstone bridge, and the Wheatstone bridge can be configured such that a potential difference across two nodes of the Wheatstone bridge circuit is variable in response to changes in the measured resistance of the electric foil strain gauge sensors.

[0011] In an embodiment, the second sensing and transducer module comprises an optical sensor module. The optical sensor module comprises an interrogator arm having a chirped fiber Bragg grating CFBG sensor and a sensing arm having a chirped fiber Bragg grating CFBG sensor or a uniform fiber Bragg grating UFBG sensor. The interrogator arm is configured to operate in either the same band or a collocated band with the sensing arm. The band of the chirped fiber Bragg grating CFBG sensor or the uniform fiber Bragg grating UFBG sensor may be selected from the linear portion of the slope (rising or descending) of a power intensity versus wavelength graph associated with a broadband light source.

[0012] In an embodiment, the interrogator arm incorporates an LED light source, and the sensing arm is operatively arranged and configured to be connected to an external device to obtain strain measurements.

[0013] In an embodiment, the data acquisition module includes a transceiver module including a single-board computer for interfacing with the selector using a universal asynchronous receiver-transmitter (UART) communication protocol.

[0014] In an embodiment, the first distortion signal and / or the second distortion signal is in the form of an analog differential voltage, which is amplified before being converted to a digital value. According to another aspect of the present disclosure, a system for monitoring strain on a structure is provided. The system includes a first sensing and transducer module having an electrical strain gauge ESG sensor attached to the structure, the electrical strain gauge ESG sensor configured to sense and acquire a first strain signal associated with application of tensile or compressive strain to the structure, and a second sensing and transducer module having an optical fiber-based sensor attached to the structure, the optical fiber-based sensor configured to sense and acquire a second strain signal. The system further includes a data acquisition module disposed in signal or data communication with the first and second sensing and transducer modules. The data acquisition module includes a selector configured to select between receiving the first strain signal and the second strain signal and to convert the received first or second strain signal to a digital value.

[0015] In one embodiment, the transceiver module comprises a single-board computer configured and arranged to receive the converted digital values ​​and to wirelessly communicate with the selector for further transmission to a terminal device for display.

[0016] In an embodiment, the first sensing and transducer module comprises a Wheatstone bridge circuit, with the electrical strain gauge ESG sensors being resistive arms of the Wheatstone bridge.

[0017] In an embodiment, the second sensing and transducer module comprises an optical sensor module having an interrogator arm with a chirped fiber Bragg grating CFBG sensor and a sensing arm with a chirped fiber Bragg grating CFBG sensor or a uniform fiber Bragg grating UFBG sensor, where the interrogator arm is configured to be either co-band or co-located with the sensing arm.

[0018] In an embodiment, at least one of the first sensing and transducer module, the second sensing and transducer module, and the data acquisition module is positioned in wireless communication with the other modules.

[0019] In an embodiment, the received first distortion signal or the received second distortion signal and the digital value are stored in a database for transmission to a terminal device. According to another aspect of the present disclosure, there is provided a method for sensing and acquiring strain data, the method comprising: acquiring a first strain signal from an electrical strain gauge ESG sensor attached to a structure and transmitting the first strain signal to a first sensing and transducer module, acquiring a second strain signal from an optical fiber based sensor attached to the structure and transmitting the second strain signal to a second sensing and transducer module, transducing the first and second strain signals to respective analog values, and selecting the respective analog values ​​and converting the analog values ​​to digital values.

[0020] In some embodiments, the method further comprises storing the converted digital values ​​in a data set for display on a computer device. The present disclosure will be better understood by reference to the detailed description when considered in conjunction with the non-limiting examples and the accompanying drawings. [Brief explanation of the drawings]

[0021] [Figure 1A-1B] 1A and 1B illustrate prior art devices for sensing and acquiring strain data based on resistance based electrical strain gauges and fiber Bragg grating (FBG) sensors, respectively. [Figure 2] 1 is a system diagram of an integrated device for sensing and acquiring strain data based on at least two sensing and transducer modules. [Figure 3] 1 is a schematic diagram of a first sensing and transducer module arranged in a Wheatstone bridge configuration, according to an embodiment. [Figure 4A] FIG. 10 illustrates one of three possible embodiments of a second sensing and transducer module utilizing a fiber optic sensor. [Figure 4B] FIG. 10 illustrates one of three possible embodiments of a second sensing and transducer module utilizing a fiber optic sensor. [Figure 4C] FIG. 10 illustrates one of three possible embodiments of a second sensing and transducer module utilizing a fiber optic sensor. [Figure 5A] 1 illustrates a data acquisition module in the form of an integrated circuit prototyping kit and built-in schematic design, according to an embodiment. [Figure 5B] 1 illustrates a data acquisition module in the form of an integrated circuit prototyping kit and built-in schematic design, according to an embodiment. [Figure 6] Flowchart of program IC prototyping kit for data acquisition. [Figure 7] FIG. 4 illustrates the integration of the various components shown in FIGS. 3, 4A, 5A, and 5B, according to an embodiment. [Figure 8A] FIG. 1 shows an experimental setup with sensors attached along the length of the beam to measure tensile and / or compressive strains for testing the integrated device. [Figure 8B] FIG. 1 shows an experimental setup with sensors attached along the length of the beam to measure tensile and / or compressive strains for testing the integrated device. [Figure 8C] FIG. 1 shows an experimental setup with sensors attached along the length of the beam to measure tensile and / or compressive strains for testing the integrated device. [Figure 8D] FIG. 1 shows an experimental setup with sensors attached along the length of the beam to measure tensile and / or compressive strains for testing the integrated device. [Figure 9A] Figure 1 shows a plot of the spectrum of optical intensity (y-axis) versus wavelength (x-axis) of transmitted light for the sensing chirped fiber Bragg grating CFBG used in this disclosure when subjected to different tensile strains in load (load) increments of 0.1 N. Shift to the right with increasing load. [Figure 9B] Figure 1 shows a plot of the optical intensity (y-axis) versus wavelength (x-axis) spectrum of the transmitted light of a sensing chirped fiber Bragg grating (CFBG) when different compressive strains are applied in load (load) increments of 0.1 N. Shift to the left with increasing load. [Figure 10A] 1 shows the load and unload curves of the sensor of the integrated device mounted on an aluminum cantilever. FIG. 2 shows the results obtained from a conventional data acquisition system DAQ (NIDAQ) and the integrated device of the present disclosure. [Figure 10B] 1 shows the load and unload curves of the sensor of the integrated device mounted on an aluminum cantilever. FIG. 2 shows the results obtained from a conventional data acquisition system DAQ (NIDAQ) and the integrated device of the present disclosure. [Figure 11A] 1A-1C show tensile load-strain data (X-axis) plotted on a normalized scale (Y-axis) illustrating results obtained from a conventional data acquisition system DAQ (NIDAQ) and the various sensors of the integrated device of the present disclosure, respectively. [Figure 11B] 1A and 1B show compressive load-strain data (X-axis) plotted on a normalized scale (Y-axis) illustrating results obtained from a conventional data acquisition system DAQ (NIDAQ) and the various sensors of the integrated device of the present disclosure, respectively. [Figure 12A]4B shows the loading and unloading curves of a sensor attached to an aluminum cantilever beam. 4C shows the results obtained from a conventional data acquisition system DAQ and the second sensing and transducer module of the integrated device of FIG. 4B. [Figure 12B] 4C shows the loading and unloading curves of a sensor attached to an aluminum cantilever beam. 4D shows the results obtained from a conventional data acquisition system DAQ and the second sensing and transducer module of the integrated device of FIG. 4C. [Figure 13] 1 illustrates an embodiment of a data acquisition module of an integrated device that can receive input from multiple sensing and transducer modules. [Figure 14] 1A and 1B. FIG. 1B is a table showing key features of the integrated device compared individually with the stand-alone prior art devices of FIGS. 1A and 1B. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following detailed description refers to the accompanying drawings, which illustrate, by way of example, specific details and embodiments in which the present disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure. Other embodiments may be utilized and structural and logical changes may be made without departing from the scope of the present disclosure. Various embodiments are not necessarily mutually exclusive, as some embodiments may be combined with one or more other embodiments to form new embodiments.

[0023] Embodiments described in the context of one of systems or methods are equally valid for other systems or methods. Features described in the context of one embodiment may be applicable to the same or similar features in other embodiments. Features described in the context of one embodiment may be applicable to other embodiments even if not explicitly described in those embodiments. Furthermore, additions and / or combinations and / or substitutions to features described in the context of one embodiment may be applicable to the same or similar features in those other embodiments.

[0024] In the context of some embodiments, the articles "a," "an," and "the" used in reference to features or elements comprise a reference to one or more of the feature or element.

[0025] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. As used herein, the term "strain data" broadly comprises values, readings, calculations, derivatives, and / or measurements relating to the change in dimension of a material relative to its initial dimension (initial length). Strain is sometimes expressed in units known as microstrain (με). The change in dimension (change-in length) can be the result of a tensile force (expressed as a positive measurement) or a compressive force (expressed as a negative measurement) that has been applied to the material.

[0026] As used herein, the term "module" refers to, forms part of, or comprises an application specific integrated circuit (ASIC), an electrical / electronic circuit, a combinational logic circuit, a field programmable gate array (FPGA), a processor (shared, dedicated, or group) that executes code, other suitable hardware components that provide the described functionality, or a combination of some or all of the above, such as a system-on-chip. The term module may also comprise memory (shared, dedicated, or group) that stores code that is executed by the processor.

[0027] The embodiments will be described in detail below. Figure 1A shows a prior art device in the form of an electrical strain gauge 1 connected to a laptop device 2 and a data acquisition (collection) system 3 to sense and acquire electrical strain data. Figure 1B shows a prior art device in the form of an optical interrogator system 5 connected to a laptop device 6 and a fiber Bragg grating (FBG) sensor 7. In both devices, a router 8 is connected to the data acquisition system 3 and the optical interrogator system 5 to facilitate remote data transfer and monitoring. As will be appreciated, multiple sets of the devices shown in Figures 1A and 1B may be required to sense and acquire strain data from various points on the structure, resulting in increased costs associated with the components.

[0028] FIG. 2 shows a schematic diagram of an apparatus 100 for sensing and acquiring strain data. The apparatus 100 may be a monitoring device and may include a data acquisition device. The data acquisition device includes a first sensing and transducer module 102 configured to sense and acquire a first strain signal, a second sensing and transducer module 104 configured to sense and acquire a second strain signal, and a data acquisition module 106 arranged in data communication with the first sensing and transducer module 102 and the second sensing and transducer module 104. The data acquisition module 106 includes a selector 108 configured to select between receiving the first strain signal and the second strain signal and convert the received first strain signal or the received second strain signal to a digital voltage value. The digital voltage value can be a digital differential voltage or a single-ended voltage value associated with signals obtained from multiple channels, depending on configuration and / or programming. In some embodiments, the single-ended voltage may be obtained based on a voltage input obtained from an input pin and a reference voltage (e.g., ground voltage).

[0029] In some embodiments, the apparatus 100 can be implemented in the form of an integrated data sensing and acquisition system capable of sensing and receiving strain data from at least one electrical sensor and at least one optical sensor. The electrical sensor may be a resistance-based sensor, whereby the first strain signal is obtained in the form of an electrical resistance value. The optical sensor may be an optical fiber sensor, in particular a fiber Bragg grating (FBG) sensor, whereby the second strain signal is obtained in the form of an optical intensity value.

[0030] FIG. 3 shows a schematic diagram of a first sensing and transducer module including a resistive sensor whose resistance changes with an applied strain force. This can be used to convert force, pressure, or tension into an electrical resistance value or change in electrical resistance. Applied strain on a surface to which the resistive sensor is applied can be measured by this change in resistance. In one embodiment, the resistive sensor is in the form of an electrical strain gauge 202, such as an electric foil strain gauge. Because the change in resistance is relatively small, the electrical strain gauge 202 can be implemented or arranged to form a resistive arm of a Wheatstone bridge circuit arrangement with four resistive arms. In such an arrangement, the electrical strain gauge 202 can be considered as resistor R4, as shown in FIG. 3. The other three arms R1, R2, and R3 can be fixed and calibrated based on the unstrained resistance value of R4.

[0031] In operation, the Wheatstone bridge is supplied with an excitation voltage, V, such as 5 volts (V). EX can be applied. The potential difference between the two nodes (V1 & V2) changes depending on the resistance of the strain gauge. The electrical strain gauge 202 can be thought of as a variable resistor that correlates to the applied and measured strain.

[0032] The output or potential difference (V0) between two nodes V1 and V2 can be mathematically expressed as follows:

[0033]

number

[0034] This can be simplified to equation (2).

[0035]

number

[0036] According to equation (2), when the ratio of the resistors on the side defined by R1 and R2 is equal to the ratio of the resistors on the side defined by R3 and R4, that is, when the condition R1 / R2=R4 / R3 is satisfied, V O It can be seen that σ is zero. In this case, the Wheatstone bridge is balanced and no strain measurement is detected in the material in which the electrical strain gauge 202 is placed or applied.

[0037] In some embodiments, the fixed resistors R1, R2, and R3 of the Wheatstone bridge are selected to be fixed values ​​that match the standard resistance value of current electrical strain gauges ESGs, for example, but not limited to, 120 Ω (ohms). That is, R1=R2=R3=120 Ω. The excitation voltage V supplied to the Wheatstone bridge EX is 5V, equation (2) can be further simplified to equation (3) as follows:

[0038]

number

[0039] Here, Δ is the change in the resistance of the electrical strain gauge ESG202 from 120 Ω when a strain force is applied to the surface of the structure to which the electrical strain gauge ESG202 is attached. As can be seen, if there is no change in resistance, the output voltage will be zero. When strain is induced or sensed on the surface to which the electrical strain gauge ES202G is attached, the resistance of the electrical strain gauge ESG202 changes by varying from 120 Ω. This change causes the bridge to become unbalanced, so the potential difference (V0) between the nodes is no longer zero. While R1, R2, and R3 are chosen to be 120 Ω to accommodate a 120 Ω strain gauge, it will be appreciated that the resistor values ​​can be substituted or adjusted to work with any resistance value for the connected strain gauges and resistors. In this case, the required analog resistance signal can be determined by the general equation (1):

[0040] 4A, 4B, and 4C show schematic diagrams of three different embodiments of second transducer 104, each comprising multiple fiber optic sensors. In the embodiment shown in Figure 4A, the second sensing and transducer module 104A comprises an LED light source 402, an optical coupler 404, a splitter 406, an interrogator arm 408, a strain sensing arm 410, and a temperature sensing arm 412. The optical signal sensed by the strain sensing arm 410 is output to a converter 414, which converts the optical signal to an electrical signal. The optical signal sensed by the temperature sensing arm 412 is output to a converter 416, which converts the optical signal to an electrical signal. The interrogator arm 408, the strain sensing arm 410, and the temperature sensing arm 412 can each be configured with a chirped fiber Bragg grating (CFBG) optical fiber sensor. In the embodiment shown in Figure 4A, all three arms (408, 410, 412) are configured with chirped fiber Bragg grating CFBGs.

[0041] The operational concept is based on the interrogation of a sensing fiber Bragg grating FBG (410, 412) using another fiber Bragg grating FBG 408 of the same band or at the same location. The LED light source 402 may be a preferably broadband light source, and the operating band of the fiber Bragg grating may be selected from the linear portion of the slope (rising or falling) of the power intensity versus wavelength graph associated with the LED light source 402. In some embodiments, the linear portion may correspond to an intermediate slope. In some embodiments, the LED light source 402 and the interrogator arm 408 may be built-in. The sensing arms (410, 412) can be externally connected when used as optical strain sensors. The three chirped fiber Bragg grating CFBG sensors in each arm (408, 410, 412) can operate in the 1300 nanometer (nm) or 1500 nm band. A bandwidth of 4-6 nm can be used for the sensing arms (410, 412), and in some embodiments bandwidths greater than 6 nm are contemplated.

[0042] The LED light source 402 may be a 1300 nm pigtailed LED light source. The fiber coupler (404) may be a (2x2) coupler, i.e., one that allows a single fiber input to be split into two outputs, or vice versa. The splitter 406, which is also an optical fiber coupler, may be a (1x2) coupler, i.e., one that allows a single fiber input to be split into two outputs, rather than vice versa. The sensed and transmitted light intensities from the strain sensing arm 410 and the temperature sensing arm 412 can be measured, received, and / or quantified using photodiodes. One chirped fiber Bragg grating CFBG is used for tensile or compressive strain measurement by attaching it to a target point on the structure. The other chirped fiber Bragg grating CFBG is used for temperature compensation without being attached to the structure.

[0043] The second sensing and transducer module 104A will now be described in the context of its operation. As shown in FIG. 4A, light from an LED light source 402 enters an interrogator arm 408 via an optical coupler 404. The light is reflected back into the optical coupler 404, and the reflected light enters a splitter (coupler) 406, where it is split between a strain-sensing arm 410 and a temperature-sensing arm 412. The transmitting ends of the strain-sensing arm 410 and the temperature-sensing arm 412 are connected to one or more photodiodes (not shown). The photodiodes convert optical power into a voltage through respective optical-to-analog converters 414 and 416. Changes in the strain sensed by the strain-sensing arm 410 result in changes in the voltage value. The temperature-sensing arm 412 is used to compensate for the effects of ambient temperature. The output of the converter 416 serves as a reference signal. Because the transmission spectrum of a fiber Bragg grating (FBG) is a function of both temperature and strain, the actual strain can be calculated by taking the difference between the converted analog values. The architecture of Figure 4A is relatively flexible and can be arranged in various combinations to operate in transmission or reflection mode depending on the application. A uniform fiber Bragg grating (UFBG) can also be used as the sensing unit, as shown in Figure 4C.

[0044] FIG. 4B shows another embodiment of the second sensing and transducer module 104B. In this embodiment, the temperature sensing arm 412 and the interrogator arm 408 are arranged in a cascade configuration or in series. Light emitted from the LED light source 402 is split between the input to the temperature sensing arm 412 and the input to the optical-to-electrical converter 418 via a splitter 406. The optical-to-electrical converter 418 generates a reference voltage signal for comparison with the optical-to-electrical converter 414. Compared to the three-chirped fiber Bragg grating CFBG architecture shown in FIG. 4A, this embodiment (104B) is comprised of two relatively inexpensive chirped fiber Bragg grating CFBGs. This provides temperature-compensated strain values, provided both chirped fiber Bragg grating CFBGs are placed at the same ambient temperature.

[0045] In another embodiment shown in FIG. 4C, the second sensing and transducer module 104C configures a uniform fiber Bragg grating (UFBG) 411 as the sensing arm. In this embodiment, the uniform fiber Bragg grating UFBG 411 is interrogated by a chirped fiber Bragg grating CFBG 408. The uniform fiber Bragg grating UFBG spectrum is configured to be around the center of the chirped fiber Bragg grating CFBG spectrum. The light source may be in the form of a SLED, which can be substituted with an LED to obtain similar data in the 1300 nm band. This is another alternative configuration that replaces the optical components of FIG. 4A with those of FIG. 4C.

[0046] The optical sensing concept using fiber Bragg gratings (FBGs) is based on interrogating a sensing chirped fiber Bragg grating (CFBG) and / or uniform fiber Bragg grating (UFBG) with another chirped fiber Bragg grating (CFBG) of the same or co-located band. The working band is selected by the intermediate slope (rising or falling edge) of a broadband light source, such as a light-emitting diode (LED). This configuration determines the sensor's operating range. When the sensing uniform fiber Bragg grating (UFBG) arm bends or senses strain, the intensity of the Bragg wavelength increases or decreases (due to the slope of the light from the chirped fiber Bragg grating (CFBG) and the monotonically varying intensity of that light), which is then captured by the transducer. The advantage of this combination compared to other architectures is that only one chirped fiber Bragg grating (CFBG) sensor and one uniform fiber Bragg grating (UFBG) sensor are required. The relatively low cost of uniform fiber Bragg gratings (UFBGs) further reduces the system cost. 4A, 4B, and 4C show three possible embodiments, it is contemplated that additional permutations of elements (404, 406, 408, 410, 412) may be envisioned by one skilled in the art to provide additional embodiments. It is further contemplated that other data, in addition to strain data, may be obtained from the second transducer 104, such as temperature data and vibration-related data.

[0047] 5A illustrates an embodiment of the data acquisition module 106 in the form of a prototyping kit 500, such as the CY8ckit-059 prototyping kit. The kit 500 can be used for the development and implementation of the data acquisition module 106. It is envisioned that the prototyping kit 500 can be replaced with a physical integrated circuit or other alternative module. As shown, the kit 500 comprises a programming and debug portion 502 and a target portion 504. The target portion 504 comprises a plurality of general-purpose input / output (GIPO) pins 506 for receiving a pair of analog inputs from each of the first sensing and transducer module 102 and the second sensing and transducer module 104. The kit 500 can include a connector, such as a USB connector, for accepting a power source (e.g., a 5V power supply) for powering the kit 500.

[0048] 5B is a schematic diagram of a programmed target portion 504 for implementing the selector 108. In the illustrated embodiment, the selector 108 comprises an analog multiplexer (AMux) 510 and an analog-to-digital converter (ADC) 512. The analog-to-digital converter ADC 512 is a high-resolution, on-chip, 20-bit analog-to-digital converter ADC. The analog-to-digital converter ADC 512 is used to convert analog voltage signals acquired from the first sensing and converter module 102 and the second sensing and converter module 104 to digital signals. The analog-to-digital converter ADC 512 may be programmed to be a multi-channel analog-to-digital converter ADC. Here, pins P3_0 and P3_1 collectively form one channel (506a). Pins P3_2 and P3_3 collectively form another channel (506b). Based on the number of general-purpose input / output GIPO pins of the kit 500, up to 23 channels can be programmed. The analog-to-digital converter ADC 512 is configured to operate in a differential mode because a potential difference between nodes (e.g., the potential difference between pins P3_1 and P3_0) needs to be taken to provide an indication of the sensed strain force associated with the first sensing and transducer module 102. Figure 5B further shows a universal asynchronous receiver-transmitter (UART) module 514 for facilitating data communication with the transceiver 110. The universal asynchronous receiver-transmitter UART module 514 can be programmed in a transmit mode to facilitate data transmission from the selector 108 to the transceiver 110.

[0049] The V1 terminal from the Wheatstone bridge circuit is connected to pin P3_0 and the V2 terminal is connected to pin P3_1 to provide a differential voltage. The output of the transducer connected to strain sensing 414 is connected to pin P3_2 and the output of the transducer connected to reference signal 416 is connected to pin P3_3.

[0050] The analog multiplexer (AMux) 510 is used to switch between receiving inputs from multiple channels, facilitating simultaneous data acquisition from various types of sensors. After switching between each channel, the analog-to-digital converter ADC 512 receives a pair of analog signals from either the first sensing and converter module 102 (P3_0, P3_1) based on resistive sensing or the second sensing and converter module 104 (P3_2, P3_3) based on optical sensing. The analog-to-digital converter ADC 512 can receive inputs one at a time from electrical or optical sensors or in batches. Various methods for receiving inputs are contemplated. The analog-to-digital converter ADC 512 then calculates the difference between each pair of signals and converts the analog signals to digital form.

[0051] It is appreciated that the number of differential channels can be increased. A differential pair is formed by using two general-purpose input / output (GPI) GIPOs. The maximum number of differential pairs can be increased up to half the total number of general-purpose input / output (GPI) GIPOs, although they do not necessarily have to be adjacent. Based on the CY8ckit-059 kit, there are 46 general-purpose input / output (GPI) GIPOs, and a maximum of 23 differential channels is possible. Through design and programming changes, up to 23 electrical strain gauge (ESG) and / or chirped fiber Bragg grating (CFBG) sensors can be connected to the kit simultaneously. In other words, using kit 500, up to 23 sensing and transducer modules can be accommodated in device 100.

[0052] However, the maximum sampling frequency provided by the analog-to-digital converter ADC is distributed among the connected channels, so the more channels used, the lower the sampling frequency per channel may be. The maximum sampling frequency may vary depending on the resolution of the selected or chosen analog-to-digital converter ADC. In a non-limiting example, with 20-bit resolution, the resolution is about 22 samples per second. This sampling rate meets the requirements for static measurements in engineering applications. The sampling frequency per channel is given by the following equation (4):

[0053]

number

[0054] The high-resolution analog-to-digital converter ADC provides on-chip gain (on-chip amplifier), which can be used to amplify the received signal. Thus, changes in the voltage difference between channels of 1 microvolt or more can be sensed. Advantageously, no external amplifier is required. While additional external components are possible, the use of on-chip amplification and a high-resolution analog-to-digital converter ADC is preferred because external circuitry may add noise to the signal. In some embodiments, the differential input (e.g., the voltage difference between pins P3_0 and P3_1 (first channel) or the voltage difference between P3_2 and P3_3 (second channel)) may be amplified by approximately seven times before being sent to the transceiver module 110 for further processing. In other words, the value plotted on the graph for display to the user is approximately seven times the differential analog voltage sensed by the device 100.

[0055] In some embodiments, the analog-to-digital converter ADC may be configured to continuously sample the analog input from each converter (102, 104). The resulting data (samples) may be processed and transmitted to the transceiver module 110. The transceiver module 110 may be configured with a single-board computer (SBC) to receive data via a universal asynchronous receiver-transmitter (UART) connection configured in receive mode to communicate with a universal asynchronous receiver-transmitter UART module 514. The universal asynchronous receiver-transmitter UART connection configured in receive mode may include another similar universal asynchronous receiver-transmitter UART module (not shown). The single-board computer SBC may further be configured to connect to a 4G Internet dongle to facilitate data transmission and reception to and from an optional terminal device (e.g., a personal computer). The transceiver module 110 and the selector module 108 may function as separate units that can interface with each other using a universal asynchronous receiver-transmitter UART communication protocol.

[0056] The output signals or data via the universal asynchronous receiver-transmitter UART module 514 can be sent to the single-board computer SBC for further processing. Once the signals are received by the single-board computer, they can be further transmitted, for example, via a wireless communication protocol, and displayed via any serial terminal program, as well as plotted using graphical user interface (GUI) software. In some embodiments, an Internet connection can be provided to the single-board computer by connecting a mobile network adapter device, such as a Universal Serial Bus (USB) dongle, to the single-board computer. The single-board computer can be remotely accessed via the Internet connection using a protocol suitable for remote access to a graphical user interface, such as the VNC (Virtual Network Computing) protocol. A user can view the data by remotely accessing it (via a wireless network) on a client terminal.

[0057] In some embodiments, the single board computer may be combined with or integrated with the data acquisition module 106 to form a single device / module / board.

[0058] 6 is a flow chart illustrating programming of a data acquisition process 600. The process begins with an initialization process 602, which initializes the analog multiplexer 510, the analog-to-digital converter ADC 512, the universal asynchronous receiver-transmitter UART module 514, the total number of channels from which sense inputs are acquired (corresponding to the number of sense and converter modules 102, 104), and setting the channel counter to zero.

[0059] After the initialization process 602, the data acquisition module 106 is configured to receive data from each converter 604, with each converter connected to one channel. For example, an analog multiplexer 510 selects a channel (e.g., 506a), and an analog-to-digital converter (ADC) 512 converts the differential voltage obtained from the Wheatstone bridge into digital data. The digital data is then sent to the single-board computer for further transmission or display using a universal asynchronous receiver-transmitter UART connection between one or more pairs of universal asynchronous receiver-transmitter UART modules. The channel counter receives data from the converters 414 and 416 and is incremented by one to select the next channel, e.g., 506b. The same data acquisition process is repeated. At the same time, the channel counter value is checked to see if it corresponds to the last channel from which data is acquired (606). If so, the channel counter is reset to 0 (608). If not, the data acquisition process is repeated for the next channel.

[0060] FIG. 7 shows an integrated system design of the embodiment described in FIGS. 3-6 with wireless capability to transmit data to an optional terminal end-user device, such as a personal computer. This design illustrates how device 100 can sense strain forces from both types of sensors (electrical and optical) simultaneously. In some embodiments, real-time data from both optical and electrical sensors can be displayed simultaneously on one screen. The unique advantages of combining two different sensing systems into one device / platform are established along with the measurement results.

[0061] FIG. 8A shows an experimental setup 800. The experimental setup 800 has an electrical strain gauge ESG sensor 202 and a chirped fiber Bragg grating CFBG sensor 410 attached to a test structure in the form of a cantilever beam 802 along the length of the cantilever beam 802. The electrical strain gauge ESG sensor 202 and the chirped fiber Bragg grating CFBG sensor 410 can be connected to the remaining components housed in a box 804 via suitable available electrical wires 806 and connectors 808. For example, the remainder of the Wheatstone bridge circuit shown in FIG. 3 and the optical components shown in FIG. 4A may be housed in the box 804. Experiments are performed to determine the amount of voltage change when the sensors 202, 410 are attached to a structure experiencing a certain amount of strain.

[0062] FIG. 8B shows a cantilever beam 802 having a length of 22.2 centimeters (cm). The fiber Bragg grating sensor 410 and the electrical strain gauge ESG sensor 202 are attached 5.5 cm from a fixed point 810 attached to an elevated structure to facilitate the application of strain forces to the cantilever beam as it pivots around the fixed point 810. FIG. 8C shows an aluminum cantilever beam attached to an elevated platform 812 and loaded with a metal strip 814 at its free end. A 0.1 N change is allowed per loading / unloading step to simulate a tensile strain force. FIG. 8D shows sensors (410, 202) positioned underneath the cantilever beam 802 (i.e., on the surface opposite from that shown in FIG. 8C) to measure compressive strain forces.

[0063] The measurement procedure has four parts: (a) Referencing the setup by using a conventional data acquisition system (DAQ) such as NI_DAQ after calibration.

[0064] (b) Loading and unloading data (microstrain με) is measured from electrical strain gauge ESG sensors 202. (c) The duty cycle is referenced for the fiber Bragg grating UFBG sensor 410 using an optical spectrum analyzer OSA.

[0065] (d) The same load and unload cycles are then recorded using the device 100. The acquired data are then compared to plot the graphs shown in Figures 9A-9E.

[0066] For calibration purposes, a conventional data acquisition system (DAQ), an NI-9237C Series Strain / Bridge Input Module, is used to record the strain forces experienced by the electrical strain gauge ESG sensor 202. Load and unload tests are performed on the free end of the aluminum cantilever beam 802 with a 0.1 N load change from 0.1 N to 0.5 N (0.1 N increments) for the load test and from 0.5 N to 0.1 N (0.1 N decrements) for the unload test, with 0.1 N load steps. The corresponding strain values ​​are recorded and used as a reference for further testing of one or more electrical strain gauges 202 and the chirped fiber Bragg grating CFBG sensor 410. It is understood that the data obtained by these sensors may be obtained via wireless communication protocols, such as broadband mobile communications, e.g., 4G mobile communications protocols.

[0067] To obtain measurements or readings of tensile strain, the experimental setup shown in Figure 8C is used. The tensile strain spectrum (intensity vs. wavelength) is recorded as shown in Figure 9A. Note that as the light intensity increases, the spectrum shifts to the right with increasing load.

[0068] To perform the compressive strain measurements, we use the experimental setup shown in Figure 8D. The compressive strain spectrum (intensity vs. wavelength) is plotted in Figure 9B. Note that the spectrum shifts to the left when the load increases as the light intensity decreases.

[0069] 10A shows a graphical plot of the change in voltage output (after the universal asynchronous receiver-transmitter UART module 514) of the developed apparatus 100 (labeled InDEO in various graphs) as the electrical strain gauge ESG 202 experiences strain from a load of 0.1 N to 0.5 N. This plot is shown in comparison to a conventional method of measuring an electrical strain gauge ESG, i.e., using a conventional data acquisition system DAQ, an NI-9237C Series strain / bridge input module. The results show that the apparatus 100 achieves similar measurements as the conventional data acquisition system DAQ.

[0070] FIG. 10B shows a graphical plot of the voltage change at the output of the developed device 100 (after the universal asynchronous receiver-transmitter UART module 514) when strain is applied to the chirped fiber Bragg grating CFBG sensor 410. Loading and unloading tests are performed to measure tensile and compressive strain. The same tests (loading only) are compared with conventional measurements using a conventional optical spectrum analyzer (OSA). The results show that the device 100 achieves similar measurements to those of the conventional optical spectrum analyzer OSA.

[0071] The data acquired and displayed in the graphs of FIGS. 10A and 10B show that linearity is observed in all graphs. Data collected via a conventional data acquisition system (DAQ) can be used to calibrate the data collected from the electrical strain gauges (ESG202). An optical spectrum analyzer (OSA) is a conventional method for measuring the chirped fiber Bragg grating (CFBG) wavelength shift and power. The data shown in FIG. 10B is used to verify the strain data obtained from the chirped fiber Bragg grating (CFBG) 410.

[0072] In some embodiments, the voltage output values ​​from the transceiver module 110 can be normalized, as shown in Figure 11A for tensile strain and Figure 11B for compressive strain. The normalized strain data has been found to match relatively well with reference data obtained from a conventional data acquisition system (DAQ).

[0073] These results demonstrate that device 100 is enabled to interrogate both optical and electrical sensors and is suitable for deployment as an integrated system for simultaneous optical and electrical strain sensing. Furthermore, device 100 is 4G-enabled, facilitating remote, real-time structural health monitoring.

[0074] Based on the comparison graphs shown in FIGS. 10 and 11, the device 100 is shown to operate seamlessly with the first sensing and transducer module 102 and the second sensing and transducer module 104.

[0075] Figure 12A shows a comparative graph plot of the second sensing and transducer module 104B shown in Figure 4B. Test results obtained based on a conventional data acquisition system DAQ and the device 100 using the experimental setup shown in Figures 8A-8D are shown in Figure 12A. The graph plot shows a response comparable to the data obtained from the commercially available data acquisition system DAQ.

[0076] Figure 12B shows a comparative graph plot of the second sensing and transducer module 104C shown in Figure 4C. Figure 12B shows test results obtained based on a conventional data acquisition system DAQ and the device 100 using the experimental setup shown in Figures 8A-8D. The graph plot shows a response comparable to the data obtained from the commercially available data acquisition system DAQ.

[0077] While the foregoing embodiments have been described with respect to two sensing and transducer modules, it will be appreciated that multiple sensing and transducer modules, up to a maximum number of channels, are contemplated. It is also contemplated that a single board computer may be integrated as part of a device in the form of a customized chip or board.

[0078] FIG. 13 is a system diagram illustrating multiple optical-based sensing and converter modules and multiple resistive-based sensing and converter modules. The embodiment of FIG. 13 allows for multiplexing of up to 23 sensing and converter modules for parallel processing, although it is contemplated that more sensing and converter modules may be multiplexed depending on configuration and / or hardware improvements. FIG. 13 shows two optical-based sensing and converter modules and one resistive-based sensing and converter module arranged in parallel, configured as inputs to an analog-to-digital converter (ADC). As previously mentioned, device 100 can include a 4G or 5G mobile network adapter device, which advantageously provides remote monitoring capabilities.

[0079] In some embodiments, the fiber Bragg grating (UFBG)-based strain signal obtained from the second sensing and transducer module 104 may be used to reference the electrical strain gauge (ESG)-based strain signal obtained from the first sensing and transducer module 102 before being wirelessly transmitted to the terminal device. The strain signal may be integrated in the form of equation (5):

[0080]

number

[0081] where I is the integrated signal sent to and / or received by the receiving device; SO is the optical sensing signal obtained from the fiber optic based sensor; SE is the electrical sensing signal obtained from the electrical strain gauge ESG based sensor; and K1, K2, and K3 are constants or functions. I can be dynamically recorded at a rate from 1 Hz to 100 Hz (or higher) based on application requirements.

[0082] Equation (5) can be generalized to equation (6) for multiple optical fiber-based sensors as follows:

[0083]

number

[0084] where q is the number of channels, and i, j, m, and n are arbitrary integers assigned to signals from the optical and electrical sensing units in device 100. Because device 100 can acquire data from multiple channels, it can be configured to monitor multiple channels by utilizing the capabilities of an on-chip programmable multiplexer.

[0085] In some embodiments, the integrated signal I, as mathematically represented in equation (5) or equation (6), may be calculated by either the selector and / or the single board computer SBC.

[0086] Advantageously, the received data does not require post-processing. Also, since the data is transmitted directly from the transmitter using the Internet network, no additional equipment is required between the transmitter and the receiver's terminal computing device, e.g., a laptop or smartphone. Any smartphone or laptop with Internet access can access the available data. The device 100 can be configured as a standalone unit at the sensing / transmission point.

[0087] In some embodiments, one or more idle strain gauges can be attached to the device 100 to mitigate interference from the device itself. The strain data received by the user device is representative of the optical sensors. The use of idle strain gauges allows for explicit reception of additional device profiling / device drift. The use of strain gauges may eliminate the need for post-processing to monitor the sensed signal. Furthermore, edge processing can be performed in real time within the device to mitigate fluctuations. The idle strain gauges can be used to reference ambient or environmental conditions, including any thermal drift of the device 100. Because the idle strain gauge's electrical strain gauge ESG accounts for such thermal drift, it can also be used as a cross-check sensor to instantly correct readings from each chirped fiber Bragg grating CFBG1-chirped fiber Bragg grating CFBG2-electrical strain gauge ESG sensor before transmitting data.

[0088] It is contemplated that the apparatus 100 may be applied to a variety of applications, including, but not limited to, civil structures, mechanical structures, and marine structures. It is further contemplated that the apparatus 100 may form part of or be incorporated into a cloud-based system or platform. Data obtained from the first sensing and transducer module 102 and the second sensing and transducer module 104 may be unified for optical sensors and electrical strain gauges, facilitating more efficient analysis and interpretation.

[0089] It is contemplated that the data acquisition module 106 may include additional components for signal processing and wireless transmission and reception. It is envisioned that the sensors on device 100 include wireless transmitters and / or receivers and further include an intelligent controller that receives data from the sensors. Such an arrangement advantageously facilitates integration of device 100 into existing Internet of Things (IoT) platforms and co-deployment with other IoT sensors.

[0090] Figure 14 provides a brief summary of the cost advantages of apparatus 100 over the prior art devices shown in Figures 1A and 1B. When read in conjunction with the results shown in Figures 10-12, apparatus 100 as an integrated device of the present disclosure demonstrates consistent measurements with currently established data acquisition systems at a fraction of the cost.

[0091] While the present disclosure has been particularly shown and described with reference to particular embodiments, it should be understood by those skilled in the art that various changes in form and detail can be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims. The scope of the present disclosure is therefore indicated by the appended claims, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced accordingly.

Claims

1. An apparatus as a data sensing and acquisition device, the apparatus comprising: a first sensing and transducer module configured to sense and acquire a first strain signal; a second sensing and transducer module configured to sense and acquire a second strain signal; a data acquisition module arranged in signal or data communication with the first sensing and transducer module and the second sensing and transducer module, the data acquisition module including a selector configured to select between receiving the first strain signal and receiving the second strain signal and to convert the received first strain signal or the received second strain signal to a digital value; The device comprises:

2. the first sensing and transducer module comprises an electrical strain gauge acquisition unit having an electrical foil strain gauge sensor; 2. The apparatus of claim 1.

3. the first sensing and transducer module comprises a Wheatstone bridge circuit; the electric foil strain gauge sensors form arms of the Wheatstone bridge circuit; 3. The apparatus of claim 2.

4. the Wheatstone bridge circuit is configured such that a potential difference across two nodes of the Wheatstone bridge circuit is variable in response to changes in measured resistance of the electric foil strain gauge sensors.

4. The apparatus of claim 3.

5. the second sensing and transducer module comprises an optical sensor module, the optical sensor module comprising an interrogator arm having a chirped fiber Bragg grating (CFBG) sensor and a sensing arm having a chirped fiber Bragg grating (CFBG) sensor or a uniform fiber Bragg grating (UFBG) sensor; the interrogator arm is configured to operate either in the same band or co-located with the sensing arm; An apparatus according to any one of claims 1 to 4.

6. the bandwidth of the chirped fiber Bragg grating CFBG sensor or the uniform fiber Bragg grating UFBG sensor is selected from a linear portion of a slope, up or down, of a power intensity vs. wavelength graph associated with a broadband light source; 6. The apparatus of claim 5.

7. the interrogator arm incorporating or connected to an LED light source; the sensing arm being operatively arranged to be connected to an external device to obtain strain measurements; 6. The apparatus of claim 5.

8. the data acquisition module comprises a transceiver module; the transceiver module comprising a single board computer for interfacing with the selector using a universal asynchronous receiver-transmitter (UART) connection; An apparatus according to any one of claims 1 to 4.

9. at least one of the selector and the single-board computer is configured to combine the first distortion signal and the second distortion signal; 9. The apparatus of claim 8.

10. At least one of the first distortion signal and the second distortion signal is in the form of an analog differential voltage; the analog differential voltage is amplified prior to conversion to the digital value; An apparatus according to any one of claims 1 to 4.

11. 1. A system for monitoring distortion of a structure, the system comprising: a first sensing and transducer module having an electrical strain gauge ESG sensor attached to the structure, the electrical strain gauge ESG sensor configured to sense and acquire a first strain signal associated with application of a tensile or compressive strain to the structure; a second sensing and transducer module having a fiber optic based sensor attached to the structure, the fiber optic based sensor configured to sense and acquire a second strain signal; and a data acquisition module arranged in signal or data communication with the first sensing and transducer module and the second sensing and transducer module, the data acquisition module including a selector configured to select between receiving the first strain signal and receiving the second strain signal and to convert the received first strain signal or the received second strain signal to a digital value; The system comprises:

12. The system further comprises a single board computer; the single-board computer is arranged to wirelessly communicate with the data acquisition module to receive the converted digital values ​​and to further transmit them to a terminal device for display; The system of claim 11.

13. the first sensing and transducer module comprises a Wheatstone bridge circuit; the electrical strain gauge ESG sensor is a resistive arm of the Wheatstone bridge circuit; The system of claim 11.

14. the second sensing and transducer module comprises an optical sensor module; the optical sensor module comprises an interrogator arm having a chirped fiber Bragg grating CFBG sensor and a sensing arm having a chirped fiber Bragg grating CFBG sensor or a uniform fiber Bragg grating UFBG sensor; the interrogator arm is configured to be either co-band or co-located with the sensing arm; A system according to any one of claims 11 to 13.

15. At least one of the first sensing and transducer module, the second sensing and transducer module, and the data acquisition module is arranged to be wirelessly communicable with the other modules. A system according to any one of claims 11 to 13.

16. The received first distortion signal or the received second distortion signal and the digital value are stored in a database for transmission to a terminal device. A system according to any one of claims 11 to 13.

17. at least one of the selector and the single-board computer is configured to combine the first distortion signal and the second distortion signal; The system of claim 12.

18. 1. A method for sensing and acquiring strain data of a structure, the method comprising: acquiring a first strain signal from an electrical strain gauge ESG sensor attached to the structure and transmitting the first strain signal to a first sensing and transducer module; acquiring a second strain signal from a fiber optic based sensor attached to the structure and transmitting the second strain signal to a second sensing and transducer module; converting the first distortion signal and the second distortion signal to respective analog values; selecting each of said analog values ​​and converting said analog values ​​to a digital value; The method comprises:

19. The method further comprises storing the converted digital values ​​in a data set for display on a computer device.

20. The method of claim 18.

20. 1. An apparatus for sensing and acquiring data, the apparatus comprising: a first sensing and transducer module configured to sense and acquire a first strain signal; a second sensing and transducer module configured to sense and acquire a second strain signal; a data acquisition module arranged in signal or data communication with the first sensing and transducer module and the second sensing and transducer module, the data acquisition module including a selector configured to select between receiving the first strain signal and receiving the second strain signal and to convert the received first strain signal or the received second strain signal to a digital value; Equipped with the data acquisition module further comprises a single-board computer for interfacing with the selector using a universal asynchronous receiver-transmitter (UART) connection, at least one of the selector and the single-board computer configured to combine the first distortion signal and the second distortion signal. system.

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