Flexible strain sensor

Abstract

The invention provides a flexible strain sensor, and relates to the technical field of sensing and measurement and control. The flexible strain sensor comprises a flexible distributed wire, a signal transceiver and a controller, the flexible distributed wire comprises M + 1 sections of flexible units, an insulator capable of causing the size change of a conducting layer is arranged between every two adjacent sections of flexible units, and the conducting layer of the flexible distributed wire comprises liquid metal; under the condition that the flexible distributed wire does not deform, the signal transceiver transmits a test waveform to the flexible distributed wire and receives a waveform reflected in the flexible distributed wire; the controller takes the reflected waveform as a baseline waveform; the signal transceiver periodically transmits a test waveform to the flexible distributed wire and receives a reflection waveform reflected in the flexible distributed wire; and the controller determines the deformation position and the deformation type of the flexible distributed wire according to the reflection waveform and the baseline waveform.

Description

Technical Field

[0001] The present disclosure relates to the field of sensing and measurement and control technologies, and in particular to a flexible strain sensor. Background Art

[0002] With the development of deformation measurement technologies, the requirements for the accuracy of landslide monitoring are getting higher and higher.

[0003] Landslide deformation mainly includes two types: surface deformation and depth deformation. Generally, the deformation range of landslide deformation is large, the deformation duration is long, the deformation evolution behavior is complex (for example, the deformation speed is very slow or has sudden changes), the terrain is complex, and the surrounding environment changes with time and space.

[0004] Currently, the TDR (Time Domain Reflectometry) technology is widely used in landslide monitoring. The TDR technology is based on the mechanism that when electromagnetic waves are transmitted in a cable, reflection waves will be generated when encountering different medium interfaces or faults for deformation measurement. One method is to use the TDR technology based on coaxial cables to install the coaxial cables in the boreholes of landslides for deep deformation measurement. However, the elastic modulus of coaxial cables is usually greater than 10 GPa, resulting in a small deformation on the coaxial cable under a small slip stress, and the change in the reflected signal is not obvious, and only obvious large deformations can be detected. And large deformations usually easily cause the coaxial cable to break, resulting in measurement failure and inability to be reused. Another method is to use the TDR technology based on flexible wires for measurement. However, currently, the measurement method based on flexible wires can only determine that overall tensile deformation has occurred and cannot accurately locate the position where the tensile deformation occurs. In the case of simultaneous tensile and compressive deformations, the specific positions and types of tensile and compressive deformations cannot be determined.

[0005] Therefore, the reliability of the above two deformation measurement methods is currently low and the accuracy is poor. Summary of the Invention

[0006] To overcome the problems existing in the related art, the present disclosure provides a flexible strain sensor.

[0007] According to a first aspect of the embodiments of the present disclosure, a flexible strain sensor is provided. The flexible strain sensor includes: a flexible distributed wire, a signal transceiver, and a controller; the flexible distributed wire includes M + 1 flexible units, and an insulator that can cause a change in the size of the conductive layer is included between two adjacent flexible units. The conductive layer of the flexible distributed wire includes liquid metal, where M is a positive integer; when the flexible distributed wire is not deformed, the signal transceiver emits a test waveform into the flexible distributed wire and receives the waveform reflected in the flexible distributed wire; the controller uses the reflected waveform as a baseline waveform, where the head and tail of the flexible distributed wire correspond to two wave peaks at the head and tail of the baseline waveform, and the position of each insulator in the flexible distributed wire corresponds to a wave peak of the baseline waveform; the signal transceiver periodically emits a test waveform into the flexible distributed wire and receives the reflected waveform reflected in the flexible distributed wire; the controller determines the position and type of deformation of the flexible distributed wire according to the reflected waveform and the baseline waveform.

[0008] Optionally, the insulator is M groups of protrusions or grooves horizontally distributed on the flexible insulating layer, and the flexible insulating layer is a flexible sleeve of the flexible distributed wire.

[0009] Optionally, determine the time difference between each wave peak and the wave peak adjacent in time and earlier; based on the time difference and a first preset formula, determine the length of each flexible unit in the flexible distributed wire; the first preset formula includes: where Δt i,i+1 represents the time difference between the (i + 1)-th wave peak and the i-th wave peak; L i,i+1 represents the length of the i-th flexible unit; V f represents the propagation speed of electromagnetic waves in the flexible distributed wire.

[0010] Optionally, if the reflected waveform is the same as the baseline waveform, the controller determines that the flexible distributed wire has not deformed; if the reflected waveform is different from the baseline waveform, the controller determines that the flexible distributed wire has deformed.

[0011] Optionally, if the time length of the reflected waveform is greater than the time length of the baseline waveform, the controller determines that the flexible distributed wire has undergone tensile deformation; if the number of wave peaks of the reflected waveform is greater than the number of wave peaks of the baseline waveform, the controller determines that the flexible distributed wire has undergone compressive deformation.

[0012] Optionally, if the time length of the reflected waveform is greater than that of the baseline waveform and the number of peaks on the reflected waveform is the same as that on the baseline waveform, the controller determines that tensile deformation has occurred and no compressive deformation has occurred; if the time length of the reflected waveform is equal to that of the baseline waveform and the number of peaks on the reflected waveform is greater than that on the baseline waveform, the controller determines that no tensile deformation has occurred in the flexible distributed wire and compressive deformation has occurred; if the time length of the reflected waveform is greater than that of the baseline waveform and the number of peaks on the reflected waveform is greater than that on the baseline waveform, the controller determines that both tensile deformation and compressive deformation have occurred in the flexible distributed wire.

[0013] Optionally, after the controller determines that tensile deformation has occurred in the flexible distributed wire, the controller determines the time difference between each peak on the reflected waveform and the peak adjacent in time and earlier, and re-determines the length of each flexible unit; based on the length difference between each flexible unit and the initial length, it determines the flexible units that have undergone tensile deformation; and determines the time difference between each peak on the reflected waveform and the peak at the starting end to locate the positions of the flexible units that have undergone tensile deformation.

[0014] Optionally, if the number of peaks on the reflected waveform is K more than the number of peaks on the baseline waveform, the controller determines that compressive deformation has occurred at K positions of the flexible distributed wire, where K is a positive integer.

[0015] Optionally, if the time difference between two consecutive peaks on the reflected waveform is less than the time length of the baseline unit corresponding to the baseline waveform, there is a peak corresponding to compressive deformation between the two peaks.

[0016] Optionally, if the number of peaks on the reflected waveform is less than the number of peaks on the baseline waveform, and / or the time length of the reflected waveform is less than the time length of the baseline waveform, the controller determines that the flexible distributed wire has broken.

[0017] According to a second aspect of the embodiments of the present disclosure, a control device is provided, including: a processor; a memory for storing instructions executable by the processor; wherein the processor is configured to: execute the steps of the method performed by the controller in the flexible strain sensor described in the first aspect above.

[0018] The technical solutions provided by the embodiments of the present disclosure may include the following beneficial effects:

[0019] In the embodiments of the present disclosure, the flexible strain sensor includes a flexible distributed wire, a signal transceiver, and a controller. Since the flexible distributed wire includes an insulator that can cause a change in the size of the conductive layer, the insulator divides the flexible distributed wire into multiple flexible units. When an electromagnetic wave is transmitted in the flexible distributed wire of this structure, a reflected wave peak is generated at each position where the size changes. After the flexible distributed wire is arranged in the area to be monitored, the signal transceiver emits an electromagnetic wave into the flexible distributed wire, first obtains a baseline waveform, and then during the monitoring of deformation, the electromagnetic wave can be periodically emitted into the flexible distributed wire. Information such as whether the flexible distributed wire is deformed, the flexible unit where the deformation occurs, and the type of deformation can be determined by analyzing the change of the monitored reflected waveform compared with the baseline waveform. That is, the monitoring accuracy is high, the repeatability is high, and various deformation types can be monitored to provide comprehensive and accurate data, which is of great significance for improving the landslide warning efficiency of the area to be monitored, optimizing the structural maintenance plan of the area to be monitored, and enhancing the overall safety of the system. For a traditional flexible wire, when it is stretched and deformed at one position, the entire flexible wire will deform, and only the length after overall stretching can be determined, and the specific position of the stretching deformation cannot be accurately located. That is, if there are tensile stresses at multiple discontinuous positions, the traditional flexible wire cannot accurately determine the positions of each stretching segment and the stretching lengths of each segment, and the accuracy of deformation monitoring is poor. While a traditional rigid wire is prone to break under stress, and the accuracy and repeatability of deformation monitoring are poor.

[0020] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings herein are incorporated into the specification and constitute a part of the present disclosure, showing embodiments consistent with the present disclosure and used together with the specification to explain the principles of the present disclosure.

[0022] Figure 1 It is a schematic structural diagram of a flexible strain sensor provided by an embodiment of the present disclosure.

[0023] Figure 2 It is a schematic flowchart of a deformation measurement method based on a flexible strain sensor provided by an embodiment of the present disclosure.

[0024] Figure 3 It is a schematic structural diagram of a flexible distributed wire provided by an embodiment of the present disclosure.

[0025] Figure 4 It is a schematic diagram of a baseline waveform provided by an embodiment of the present disclosure.

[0026] Figure 5 It is one of the schematic diagrams of a monitored reflected waveform provided by an embodiment of the present disclosure.

[0027] Figure 6 Schematic diagram II of a monitored reflection waveform provided by an embodiment of the present disclosure.

[0028] Figure 7 Schematic diagram III of a monitored reflection waveform provided by an embodiment of the present disclosure.

[0029] Figure 8 Schematic diagram IV of a monitored reflection waveform provided by an embodiment of the present disclosure.

[0030] Figure 9 Hardware structure diagram of a computer device where a controller is located provided by an embodiment of the present disclosure. Detailed implementation manners

[0031] Here, exemplary embodiments will be described in detail, and examples thereof are shown in the drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation manners described in the following exemplary embodiments do not represent all implementation manners consistent with the present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0032] The terms used in the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The singular forms "a", "the", and "said" used in the present disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0033] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "when" or "while" or "in response to determining".

[0034] Next, the embodiments of the present disclosure will be described in detail.

[0035] Figure 1 Schematic diagram of the structure of a flexible strain sensor provided by an embodiment of the present disclosure, as Figure 1As shown in the figure, the flexible strain sensor 100 includes: a flexible distributed wire 101, a signal transceiver 102, and a controller 103; the flexible distributed wire 101 includes M + 1 flexible units 1011, and an insulator that can cause a change in the size of the conductive layer is included between two adjacent flexible units 1011. The conductive layer of the flexible distributed wire 101 includes liquid metal, and M is a positive integer.

[0036] It can be understood that the outer insulating layer of the flexible distributed wire is wrapped outside the flexible unit, and the insulator that causes the change in the size of the conductive layer can be provided on the outer insulating layer.

[0037] It should be noted that after the flexible distributed wire is deformed by force, if the applied force is withdrawn, the flexible distributed wire can return to its original state, so that deformation monitoring can be repeatedly performed based on the flexible distributed wire.

[0038] Optionally, the material of the insulator and the material of the outer insulating layer of the flexible distributed wire can be the same or different, and the embodiments of the present disclosure do not make specific limitations on this.

[0039] Optionally, the lengths of two adjacent flexible units can be the same or different, and the embodiments of the present disclosure do not make specific limitations on this.

[0040] Optionally, the number of insulators in the cross-sections at different positions can be the same or different, and the distribution of the insulators in the cross-sections at different positions can be the same or different. The embodiments of the present disclosure do not make specific limitations on this.

[0041] In the embodiments of the present disclosure, for the convenience of illustration, an example is given in which the lengths of two adjacent flexible units are the same, and the number and distribution of insulators in different cross-sections are the same.

[0042] Figure 2 It is a schematic flowchart of a deformation measurement method based on a flexible strain sensor provided by an embodiment of the present disclosure. As Figure 2 shown in the figure, it includes the following S201 to S204:

[0043] S201. When the flexible distributed wire is not deformed, the signal transceiver transmits a test waveform into the flexible distributed wire and receives the waveform reflected in the flexible distributed wire.

[0044] Exemplarily, the test waveform can be a step electromagnetic waveform or a pulse electromagnetic waveform.

[0045] In practical applications, surveyors can arrange the flexible distributed wires of the flexible strain sensor at the positions to be monitored, such as buried in the soil layer on the hillside or buried in the mountain body. After the arrangement is completed, the signal transceiver can be controlled to emit electromagnetic waves into the flexible distributed wires, and the controller can receive the reflected waveform in the flexible distributed wires through the signal transceiver to obtain the baseline waveform in advance, so as to determine the type and position of the deformation based on the baseline waveform and the reflected waveform during the subsequent monitoring process.

[0046] S202. The controller takes the reflected waveform as the baseline waveform.

[0047] Among them, the head and tail of the flexible distributed wire correspond to the two wave peaks at the head and tail of the baseline waveform, and the position of each insulator in the flexible distributed wire corresponds to a wave peak of the baseline waveform.

[0048] Optionally, after the flexible distributed wire is deformed, if the stress disappears or becomes stable, a new baseline waveform can be regenerated based on the reflected waveform after deformation, or the initial baseline waveform can also be used. The embodiments of the present disclosure do not make specific limitations on this. For the convenience of description, in the subsequent embodiments of the present disclosure, the initial baseline waveform is taken as an example for illustrative description.

[0049] S203. The signal transceiver periodically emits a test waveform into the flexible distributed wire and receives the reflected waveform in the flexible distributed wire.

[0050] It can be understood that the signal transceiver can periodically emit test electromagnetic waves into the flexible distributed wire. The test electromagnetic waves are transmitted in the wire and reflected back to the signal transceiver, and then the signal transceiver sends the reflected waveform in the flexible distributed wire to the controller, so that the controller can analyze the deformation situation of the flexible distributed wire based on the reflected waveform and the baseline waveform.

[0051] S204. The controller determines the position and type of deformation of the flexible distributed wire according to the reflected waveform and the baseline waveform.

[0052] Specifically, the controller can determine the deformation situation of the flexible distributed wire according to the waveform change characteristics of the reflected waveform and the baseline waveform within the measurement period.

[0053] It should be noted that in actual measurement, due to measurement errors and signal changes, the peak amplitude and position of the reflected waveform measured each time will shift. Therefore, the controller can first locate the wave peaks at the head and tail of the flexible distributed wire based on the baseline waveform, and then analyze the waveform change characteristics based on the number of wave peaks of the reflected waveform and the change of the wave peak position relative to the baseline waveform.

[0054] Embodiments of the present disclosure provide a flexible strain sensor, which includes a flexible distributed wire, a signal transceiver, and a controller. Since the flexible distributed wire includes an insulator that can cause a change in the size of the conductive layer, the insulator divides the flexible distributed wire into multiple flexible units. When an electromagnetic wave is transmitted in the flexible distributed wire of this structure, a reflected wave peak is generated at each position where the size changes. After the flexible distributed wire is arranged in the area to be monitored, the signal transceiver emits an electromagnetic wave into the flexible distributed wire to first obtain a baseline waveform. Then, during the monitoring of deformation, an electromagnetic wave can be periodically emitted into the flexible distributed wire. Information such as whether the flexible distributed wire is deformed, the flexible unit where the deformation occurs, and the type of deformation can be determined by analyzing the change in the monitored reflected waveform compared to the baseline waveform. That is, the monitoring accuracy is high, the repeatability is high, and multiple deformation types can be monitored to provide comprehensive and accurate data, which is of great significance for improving the landslide warning efficiency of the area to be monitored, optimizing the structural maintenance plan of the area to be monitored, and enhancing the overall safety of the system. In the case of a traditional flexible wire, when a position is subjected to tensile deformation, the flexible wire will be deformed as a whole, and only the length after overall stretching can be determined. It is impossible to accurately locate the specific position of the tensile deformation. That is, if there is tensile stress at multiple discontinuous positions, the traditional flexible wire cannot accurately determine the positions of each tensile segment and the lengths of stretching of each segment, and the accuracy of deformation monitoring is poor. And traditional rigid wires are prone to breakage under stress, and the accuracy and repeatability of deformation monitoring are poor.

[0055] Optionally, in the flexible distributed wire provided by the embodiments of the present disclosure, the insulator is M groups of protrusions or grooves horizontally distributed on the flexible insulating layer, the flexible insulating layer is a flexible sleeve of the flexible distributed wire, and the liquid metal wraps inside the flexible sleeve.

[0056] Optionally, the protrusions that cause the change in the size of the conductive layer may be the same as or different from the material of the flexible insulating layer of the flexible distributed wire. The embodiments of the present disclosure do not make specific limitations on this.

[0057] Figure 3 is a schematic structural diagram of a flexible distributed wire provided by an embodiment of the present disclosure. As Figure 3 shown in, the flexible distributed wire may include 3 flexible units. Among them, the flexible distributed wire is mainly composed of a liquid metal conductive core 301 and a flexible insulating layer 302. As Figure 3 shown in (a) of, an insulating block 303a is provided between two adjacent flexible units, and the cross-section of the flexible distributed wire includes a cross-section 304a and a cross-section 304b. As Figure 3 shown in (b) of, a groove 303b is provided between two adjacent flexible units, and the cross-section of the flexible distributed wire includes two cases of a cross-section 304c and a cross-section 304b.

[0058] Among them, the size of the liquid metal conductive core of the flexible distributed wire is variable (diameter and length). If the flexible distributed wire is not compressed or stretched, the diameter of the liquid metal conductive core remains unchanged, and thus the peak position and the number of peaks of the reflected waveform monitored by the signal transceiver do not change. If the flexible unit is compressed or stretched, the diameter of the liquid metal conductive core corresponding to this section of the flexible unit will change, and thus at least one of the peak position and the number of peaks of the reflected waveform monitored by the signal transceiver will change.

[0059] It should be noted that the above examples are only for illustrative purposes. In actual applications, the number of protrusions (grooves) in the cross-section can also be multiple, and the embodiments of the present disclosure do not make specific limitations in this regard.

[0060] For the convenience of description, in the subsequent examples of the present disclosure, the structure shown in (a) in Figure 3 is used for illustrative purposes. Among them, the total length of the flexible distributed wire is 90 cm, and inlays are embedded at 30 cm and 60 cm to form protrusions, that is, M = 2. The flexible distributed wire includes 3 flexible units, each with an initial length of 30 cm. An insulating block accounting for 30% of the cross-section of the flexible distributed wire is embedded between adjacent two flexible units. The material of the insulating block is silicone PDMS (Polydimethylsiloxane), the diameter of the metal conductive core is 1 mm, the material is gallium indium tin liquid metal, the outer insulating material is PDMS, and the shell thickness is 0.5 mm.

[0061] It should be noted that the preparation and composition of the above parameter materials are only for illustrative purposes. In actual applications, flexible distributed wires made of other materials and sizes can be used, and the embodiments of the present disclosure do not make specific limitations in this regard.

[0062] Optionally, for the flexible strain sensor provided by the embodiments of the present disclosure, when determining the baseline waveform, S201 above may specifically include S201a and S201b below:

[0063] S201a. The controller determines the time difference between each peak and the adjacent peak with a prior time.

[0064] Optionally, in the embodiments of the present disclosure, the lengths of two adjacent flexible units in the flexible distributed wire may be the same or different, and the embodiments of the present disclosure do not make specific limitations in this regard.

[0065] S201b. The controller determines the length of each flexible unit in the flexible distributed wire based on the time difference and formula (1).

[0066]

[0067] Among them, Δti,i+1 represents the time difference between the (i + 1)-th peak and the i-th peak; L i,i+1 represents the length of the i-th flexible unit; V f represents the propagation speed of electromagnetic waves in the flexible distributed wire.

[0068] Among them, the propagation speed of electromagnetic waves is different in different materials.

[0069] It can be understood that the controller can determine the length of each flexible unit by determining the time difference between each peak and the adjacent peak with an earlier time. If the lengths of two adjacent flexible units are the same, the length of any corresponding flexible unit can be determined by determining the time difference between any adjacent peaks, so as to determine the length of each flexible unit; if the lengths of two adjacent flexible units are different, calculate the time difference between every two adjacent peaks, thereby the length of each flexible unit can be determined.

[0070] It should be noted that since the transmission line of electromagnetic waves in the wire is related to the material of the external insulating shell, in the experimental verification of the embodiments of the present disclosure, first prepare a section of flexible distributed wire according to the above parameters, measure the length of the flexible distributed wire, test the time difference between the starting peak and the ending peak, and calculate the propagation speed of electromagnetic waves in this kind of flexible distributed wire according to the above formula. In the embodiments of the present disclosure, when using PDMS material, the transmission speed of electromagnetic waves is 1.6×10 8 m / s.

[0071] Figure 4 is a schematic diagram of a baseline waveform provided by the embodiments of the present disclosure. As Figure 4 shown in the figure, the horizontal axis is time, the vertical axis is voltage, the time length of the baseline waveform is 11.7 ns, and there are 4 peaks on the waveform. Among them, peak A1 is generated at the starting end of the flexible distributed wire (i.e., the starting end of the first unit), peak A2 is generated at the first protrusion (i.e., the contact position between the first unit and the second unit), peak A3 is generated at the second protrusion (i.e., the contact position between the second unit and the third unit), and peak A4 is generated at the ending end of the flexible distributed wire (i.e., the ending end of the third unit). Among them, the time difference between peak A1 and peak A2, and the corresponding wire distance are shown in Table 1.

[0072] Table 1

[0073] Adjacent wave peaks Time difference Distance between wires A1 - A2 3.7 ns 29.6 cm A2 - A3 3.8 ns 30.4 cm A3 - A4 4.2 ns 33.6 cm

[0074] That is to say, the lengths of the first unit, the second unit and the third unit calculated according to the baseline waveform characteristics and the formula are 29.6 cm, 30.4 cm and 33.6 cm respectively, which are in line with the actual sizes of each unit, 30 cm, 30 cm and 30 cm, within the error range.

[0075] Based on this solution, the controller can generate a baseline waveform based on the waveform reflected when there is no deformation, so as to subsequently determine the deformation of the flexible distributed wire based on this baseline waveform. Specifically, by comparing the reflected waveform and the baseline waveform, the change situation of the waveform after deformation can be determined, and thus the deformation suffered by the flexible distributed wire can be determined based on the change situation, such as the change in the number of wave peaks, the change in the time difference between adjacent wave peaks, and the change in the time difference between the starting wave peak and the ending wave peak.

[0076] Optionally, for the flexible strain sensor provided in the embodiments of the present disclosure, the above S204 can be specifically executed by the following S204a or S204b:

[0077] S204a. If the reflected waveform is the same as the baseline waveform, the controller determines that the flexible distributed wire has not deformed.

[0078] It can be understood that in the case where the flexible distributed wire does not generate deformation, the reflected waveform and the baseline waveform are theoretically exactly the same. In actual measurement, due to measurement errors, jitter, interference and attenuation of electromagnetic wave transmission, etc., the amplitude and position of the wave peaks may change. Therefore, the same waveform mentioned in the embodiments of the present disclosure means that the number of wave peaks is the same, the time difference between wave peaks is the same, and the time difference between the starting and ending wave peaks is the same.

[0079] S204b. If the reflected waveform is different from the baseline waveform, the controller determines that the flexible distributed wire has deformed.

[0080] Exemplarily, in the embodiments of the present disclosure, the different waveforms may include at least one of the following: different total waveform durations, or different total numbers of wave peaks, or different time differences between adjacent wave peaks.

[0081] Based on this solution, after the controller monitors the reflected waveform, it can first determine whether there is a change in the reflected waveform relative to the baseline waveform to preliminarily determine whether the flexible distributed wire has generated waveform deformation. If there is a change, it can quickly determine that the flexible distributed wire has generated deformation, that is, deformation has occurred in the monitoring area where the flexible distributed wire is located. If the waveform has no change, it can be determined that the flexible distributed wire has not generated deformation, that is, no deformation has occurred in the monitoring area where the flexible distributed wire is located.

[0082] Optionally, for the flexible strain sensor provided in the embodiments of the present disclosure, if the time length of the reflected waveform is greater than the time length of the baseline waveform, the controller determines that the flexible distributed wire has undergone tensile deformation; if the number of wave peaks of the reflected waveform is greater than the number of wave peaks of the baseline waveform, the controller determines that the flexible distributed wire has undergone compressive deformation.

[0083] Based on this solution, the controller can determine whether the flexible distributed wire undergoes tensile deformation based on the change in the time length in the waveform. If the time length of the reflected waveform increases, it is determined that the flexible distributed wire has undergone tensile deformation. If the number of wave peaks of the reflected waveform increases, it is determined that the flexible distributed wire has undergone compressive deformation.

[0084] Specifically, the flexible strain sensor provided by the embodiments of the present disclosure can determine the type of deformation that occurs in the following manner.

[0085] Method 1: If the time length of the reflected waveform is greater than the time length of the baseline waveform, and the number of wave peaks on the reflected waveform is the same as the number of wave peaks on the baseline waveform, the controller determines that tensile deformation has occurred and no compressive deformation has occurred.

[0086] Method 2: If the time length of the reflected waveform is equal to the time length of the baseline waveform, and the number of wave peaks on the reflected waveform is more than the number of wave peaks on the baseline waveform, the controller determines that the flexible distributed wire has not undergone tensile deformation and compressive deformation has occurred.

[0087] For example, if the number of wave peaks increases by 3, it can be determined that at least 3 compressive deformations have occurred.

[0088] Method 3: If the time length of the reflected waveform is greater than the time length of the baseline waveform, and the number of wave peaks on the reflected waveform is more than the number of wave peaks on the baseline waveform, the controller determines that the flexible distributed wire has undergone tensile deformation and compressive deformation.

[0089] Based on this solution, the controller can quickly determine the type of deformation that occurs in the flexible distributed wire roughly based on whether the number of wave peaks on the reflected waveform changes relative to the baseline waveform and whether the time changes.

[0090] Optionally, for the flexible strain sensor provided by the embodiments of the present disclosure, when it is determined that the flexible wire has undergone tensile deformation, the controller determines the time difference between each wave peak on the reflected waveform and the adjacent wave peak with earlier time, and re-determines the length of each flexible unit; based on the length difference between each flexible unit and the initial length, determines the flexible unit that has undergone tensile deformation; determines the time difference between each wave peak on the reflected waveform and the wave peak at the starting end, and locates the position of the flexible unit that has undergone tensile deformation.

[0091] It can be understood that in the case of tensile deformation, if the number of wave peaks does not change, it can be determined that the flexible distributed wire has not undergone compressive deformation.

[0092] Figure 5 Schematic diagram of a monitored reflected waveform provided by the embodiments of the present disclosure, as Figure 5As shown, the total duration of the reflected waveform is 20.2 ns, including 4 wave peaks, namely wave peak B1, wave peak B2, wave peak B3 and wave peak B4. The time differences between the wave peaks are calculated according to the formula, and the lengths of the flexible distributed wires corresponding to adjacent two wave peaks are shown in Table 1 respectively.

[0093] Table 2

[0094] Adjacent wave peaks Time difference Distance between wires B1 - B2 4.8 ns 38.4 cm B2 - B3 6.4 ns 51.2 cm B3 - B4 9 ns 72 cm

[0095] Determine the deformation process:

[0096] Step a1: The controller compares the monitored waveform with the baseline waveform. Since the total duration increases, tensile deformation occurs.

[0097] Step a2: The controller determines that the number of wave peaks does not change compared with the baseline waveform, so there is no compressive deformation.

[0098] Step a3: The controller determines that wave peak B1 corresponds to the starting end of the first unit, wave peak B2 corresponds to the first protrusion, wave peak B3 corresponds to the second protrusion, and wave peak B4 corresponds to the end of the third unit. According to the distances calculated from the time differences between the wave peaks, it can be determined that the first unit is stretched by 8.4 cm, the second unit is stretched by 21.2 cm, and the third unit is stretched by 42 cm.

[0099] Figure 5 The actual reflected waveform shown is the reflected waveform monitored after applying a 10-cm stretch to the first unit, a 20-cm stretch to the second unit, and a 40-cm stretch to the third unit, which is consistent with the stretching results obtained by waveform comparison and analysis.

[0100] Comparative experiment 1:

[0101] Manufacture a wire 1 without insulating blocks and with other parameters the same as those of the above flexible distributed wire. The length of wire 1 is 90 cm. The wire is divided into 3 segments. Apply a 10-cm stretch to the first segment, a 20-cm stretch to the second segment, and a 40-cm stretch to the third segment. The corresponding tensile strains are 20% strain, 40% strain, and 60% strain. Figure 6 This is a schematic diagram of a monitored reflected waveform provided by an embodiment of the present disclosure, as Figure 6As shown, there is a weak peak signal between peak C1 and peak C2, but the peak signal is very weak and it is difficult to determine the peak position. Peak C1 is the starting end of the first unit, and peak C2 is the ending end of the third unit. The time difference between peak C1 and peak C2 is 21.1 ns. According to the formula calculation, the deformed distance of wire 1 is determined to be 168.8 cm. Compared with the initial wire length, the wire length change is 78.8 cm, which is close to the actual applied length stretch of 70 cm (indirectly determining that peak C1 corresponds to the starting end of wire 1 and peak C2 corresponds to the ending end of wire 2), but the specific situation of each section of stretching cannot be located.

[0102] According to this comparative experiment, wire 1 does not have the ability to distinguish and judge non-uniform deformation, that is, it cannot accurately locate which section has been stretched and the length of each section of stretching. And the flexible distributed wire of the embodiment of the present disclosure can determine that the non-uniform stretching deformation characteristics are consistent with the applied non-uniform stretching deformation. Therefore, the flexible strain sensor provided by the embodiment of the present disclosure can test non-uniform stretching deformation.

[0103] Based on this scheme, when the time length of the reflection waveform is greater than the time length of the baseline waveform and the number of peaks on the reflection waveform is the same as the number of peaks on the baseline waveform, the controller can determine that the flexible distributed wire has not undergone compression deformation but has undergone stretching deformation. Furthermore, based on the time difference between two adjacent peaks and the time difference between two adjacent peaks corresponding to the baseline waveform, the position where the stretching occurs and the length of the stretching can be accurately located.

[0104] Optionally, for the flexible strain sensor provided by the embodiment of the present disclosure, if the number of peaks on the reflection waveform is K more than the number of peaks on the baseline waveform, the controller determines that the flexible distributed wire has undergone compression deformation at K positions, where K is a positive integer.

[0105] It can be understood that in the case of determining that compression deformation has occurred, the number of compression positions of the flexible distributed wire (that is, the number of flexible units undergoing compression deformation) can be determined according to the increased number of peaks.

[0106] Figure 7 This is a schematic diagram of the monitored reflection waveform provided by the embodiment of the present disclosure. As Figure 7 shown, the total duration of the reflection waveform is, including 7 peaks, namely peak D1, peak D2, peak D3, peak D4, peak D5, peak D6, and peak D7. The time difference between adjacent peaks and the distance of the flexible distributed wire corresponding to adjacent peaks are shown in Table 3.

[0107] Table 3

[0108] Adjacent wave peaks Time difference Distance between wires D1 - D2 2 ns 16 cm D2 - D3 1.8 ns 14.4 cm D3 - D4 1.7 ns 13.6 cm D4 - D5 2.3 ns 18.4 cm D5 - D6 1.8 ns 14.4 cm D6 - D7 2.7 ns 21.6 cm

[0109] Determine the deformation process:

[0110] Step b1: The controller determines that there are changes between the reflected waveform and the baseline waveform, so deformation has occurred.

[0111] Step b2: The controller determines that the reflected waveform has three more peaks than the baseline waveform. Therefore, the flexible distributed wire is compressed and deformed at three positions.

[0112] Step b3: The controller determines that the duration of the reflected waveform is 12.3 ns, which is considered unchanged compared to the duration of the baseline waveform of 12 ns, that is, the flexible distributed wire has not undergone tensile deformation.

[0113] Step b4: The controller determines the time difference between each peak and the peak that occurs earlier in time. Since there are seven peaks and no tensile deformation, peak D1 is the peak generated at the starting end of the flexible distributed wire, and peak D7 is the peak generated at the end of the flexible distributed wire.

[0114] The time difference between peak D1 and peak D3 is 2 ns + 1.8 ns = 3.8 ns, that is, peak D3 is generated by the first bulge. The time difference between peak D1 and peak D2 is 2 ns, which is less than 3.7 ns, and peak D2 is generated by the compressive deformation.

[0115] The time difference between peak D3 and peak D5 is 1.7 ns + 2.3 ns = 4 ns, which is approximately equal to 3.8 ns, that is, peak D5 is generated by the second bulge. Furthermore, peaks D4 and D6 are generated by the compressive deformation.

[0116] The wire length corresponding to the section between peak D1 and peak D2 is 16 cm, that is, there is compression at the 16 cm position in the first unit.

[0117] The wire length corresponding to the section between peak D3 and peak D4 is 14.4 cm, that is, there is compression at the 14.4 cm position in the second unit.

[0118] The wire length corresponding to the section between peak D5 and peak D6 is 15 cm, that is, there is compression at the 15 cm position in the third unit.

[0119] The position where the compressive deformation occurs obtained from the above waveform analysis is consistent with the applied compression position. Figure 7 This is the waveform monitored after applying compressive deformation at the midpoint positions of the first unit, the second unit, and the third unit in the embodiment of the present disclosure. That is, the flexible strain sensor provided by the embodiment of the present disclosure can accurately detect multiple compressive deformations.

[0120] Optionally, for the flexible strain sensor provided by the embodiments of the present disclosure, if the time difference between the second peak and the starting peak in the reflection waveform is less than the time difference between the second peak and the starting peak in the baseline waveform, the controller determines that compressive deformation occurs in the first flexible unit of the flexible distributed wire.

[0121] If the time difference between the end peak and the penultimate peak in the reflection waveform is less than the time difference between the end peak and the penultimate peak in the baseline waveform, the controller determines that compressive deformation occurs in the (M + 1)-th flexible unit of the flexible distributed wire.

[0122] Optionally, for the flexible strain sensor provided by the embodiments of the present disclosure, if the time difference between two consecutive peaks on the reflection waveform is less than the time length of the baseline unit on the corresponding baseline waveform, the controller determines that there is a peak corresponding to compressive deformation between the two peaks.

[0123] Figure 8 FIG. is a schematic diagram of a reflection waveform provided by the embodiments of the present disclosure. As Figure 8 shown, the total duration of the reflection waveform is 12.3 ns, including five peaks, namely peak E1, peak E2, peak E3, peak E4, and peak E5. The time difference between adjacent two peaks and the distance of the flexible distributed wire calculated according to the time difference between adjacent two peaks are shown in Table 4.

[0124] Table 4

[0125] Adjacent wave peaks Time difference Length of wire E1 - E2 2.9 ns 23.2 cm E2 - E3 2.1 ns 16.8 cm E3 - E4 3.7 ns 30 cm E4 - E5 3.6 ns 28.4 cm

[0126] Determination of the deformation process:

[0127] Step c1: The controller determines that there is a change in the reflection waveform relative to the baseline waveform, and thus determines that the flexible distributed wire has undergone deformation.

[0128] Step c2: The controller determines that one waveform is added to the reflection waveform compared with the baseline waveform, and it can be determined that compressive deformation occurs at one position.

[0129] Step c3: The controller determines that the total duration of the starting peak and the end peak of the reflection waveform is longer than that of the baseline waveform, and thus it can be determined that the flexible distributed wire has undergone tensile deformation.

[0130] Step c4: Since peak E1 is the peak corresponding to the starting end of the flexible distributed wire and peak E5 is the peak corresponding to the end of the flexible distributed wire, peaks E2, E3, and E4 are the peaks generated by compressive deformation and protrusion.

[0131] The time difference between peak E1 and peak E2 is 2.9 ns, which is less than 3.7 ns corresponding to the first unit in the baseline waveform. Therefore, peak E2 is the peak generated by compression. Thus, it can be determined that peaks E1 to E5 correspond to the starting end of the first unit, compressive deformation, the contact end of the first unit and the second unit (the first protrusion), the contact end of the second unit and the third unit (the second protrusion), and the end of the third unit in sequence. Furthermore, it can be determined that the time difference corresponding to the first unit is 2.9 ns + 2.1 ns = 5 ns, and the length of the first unit after stretching is 23.2 cm + 16.8 cm = 40 cm, that is, the length change of the first unit is 10 cm.

[0132] while Figure 8 The reflected waveform shown is the waveform monitored after applying the following deformation. Stretch the first unit by 10 cm, apply a compressive force at 20 cm from the starting end after stretching to generate compressive deformation, and do not apply a deformation force to the second unit and the third unit. That is, the position of the compressive deformation deduced from the waveform is consistent with the position of the applied compressive force, and the stretching length and the unit where the stretching occurs are consistent with the applied stretching deformation parameters. Therefore, the flexible strain sensor of the embodiments of the present disclosure can be applied to the scenario where compressive and tensile deformations occur simultaneously.

[0133] It should be noted that in practical applications, the flexible distributed wire may break due to excessive stretching force. In the above embodiments of the present disclosure, since the flexible distributed wire has strong ductility and is not prone to breakage, the above mainly determines the deformation of the flexible distributed wire in the case where the flexible distributed wire does not break. For the case of breakage, in the embodiments of the present disclosure, it is only necessary to determine that a breakage has occurred.

[0134] Optionally, for the flexible strain sensor provided by the embodiments of the present disclosure, if the number of peaks of the reflected waveform is less than the number of peaks of the baseline waveform, and / or, the time length of the reflected waveform is less than the time length of the baseline waveform, the controller determines that the flexible distributed wire has broken.

[0135] It can be understood that if the breakage occurs at a position other than the middle of the last unit of the flexible distributed wire, the number of peaks of the electromagnetic wave reflection will definitely decrease. Therefore, when it is determined that the number of peaks has decreased, the controller can determine that a breakage has occurred.

[0136] It can be understood that if the number of peaks of the reflected waveform is less than the number of peaks of the baseline waveform, and the time length of the reflected waveform is equal to or greater than the time length of the baseline waveform, the remaining part of the flexible distributed wire after breakage has also undergone tensile deformation.

[0137] It should be noted that all the above examples given in the embodiments of the present disclosure are for the following scenario: the deformation type is not known in advance, and the deformation behavior of the flexible distributed wire is determined according to the waveform change. The verification process of each of the above embodiments is as follows: (1) Apply different combinations of compression and tensile deformations; (2) Test and obtain the reflected waveform, and deduce the deformation behavior that has occurred according to the transmitted waveform; (3) Compare the consistency between the deduced deformation type and the applied deformation. The consistency is good, and the sensor function is okay.

[0138] Corresponding to the embodiments of the foregoing method, the present disclosure also provides embodiments of a device and a terminal to which the device is applied.

[0139] The embodiments of the controller of the present disclosure can be applied to computer devices, such as servers or terminal devices. The device embodiments can be implemented by software, or by hardware, or by a combination of software and hardware. Taking software implementation as an example, as a logically meaningful device, it is formed by reading the corresponding computer program instructions in the non-volatile memory into the memory and running them through the processor it controls. From a hardware level, as Figure 9 shown, it is a hardware structure diagram of a computer device where a controller provided by an embodiment of the present disclosure is located. In addition to Figure 9 the processor 910, memory 930, network interface 320, and non-volatile memory 940 shown, the server or electronic device where the controller 931 is located in the embodiment usually also includes other hardware according to the actual functions of the computer device, which will not be elaborated here.

[0140] Correspondingly, the present disclosure also provides a control device, which includes a processor; a memory for storing instructions executable by the processor; wherein, the processor is configured to: execute the steps of the method executed by the controller in the above-mentioned flexible strain sensor.

[0141] The implementation processes of the functions and roles of each module in the above device are specifically described in detail in the implementation processes of the corresponding steps in the above method, and will not be elaborated here.

[0142] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can refer to the partial descriptions of the method embodiments. The device embodiments described above are only illustrative. The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place, or may be distributed to multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of the present disclosure. Those of ordinary skill in the art can understand and implement it without creative work.

[0143] The above describes specific embodiments of the present disclosure. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the particular order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0144] Those skilled in the art will readily conceive of other embodiments of the present disclosure after considering the specification and practicing the invention herein. The present disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include known common knowledge or conventional technical means in the technical field not claimed in the present disclosure. The specification and examples are only to be considered exemplary, and the true scope and spirit of the present disclosure are pointed out by the following claims.

[0145] It should be understood that the present disclosure is not limited to the exact structures described above and shown in the figures, and various modifications and changes can be made without departing from its scope. The scope of the present disclosure is only limited by the appended claims.

[0146] The foregoing is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure.

Claims

1. A flexible strain sensor, characterized in that: The flexible strain sensor comprises: a flexible distributed wire, a signal transceiver and a controller; The flexible distributed conductor includes M+1 segments of flexible units, an insulator that can cause the size of the conductive layer to change is included between two adjacent segments of the flexible units, the conductive layer of the flexible distributed conductor includes liquid metal, and M is a positive integer; When the flexible distributed conductor is not deformed, the signal transceiver transmits a test waveform into the flexible distributed conductor and receives a waveform reflected from the flexible distributed conductor; The controller uses the reflected waveform as a baseline waveform, wherein the beginning and end of the flexible distributed conductor correspond to two peaks at the beginning and end of the baseline waveform, and the location of each insulator in the flexible distributed conductor corresponds to a peak of the baseline waveform; The signal transceiver periodically transmits a test waveform into the flexible distributed conductor and receives a reflected waveform reflected from the flexible distributed conductor; The controller determines the position and type of deformation of the flexible distributed conductor according to the reflected waveform and the baseline waveform.

2. The flexible strain sensor according to claim 1, characterized in that: The insulator is M groups of protrusions or grooves distributed laterally on the flexible insulating layer, and the flexible insulating layer is a flexible sleeve of the flexible distributed conductor.

3. The flexible strain sensor according to claim 2, characterized in that: The controller uses the reflected waveform as a baseline waveform, including: Determine the time difference between each peak and the previous and adjacent peaks; Based on the time difference and a first preset formula, determining the length of each flexible unit in the flexible distributed conductor; The first preset formula includes: Among them, Δt i,i+1 Indicates the time difference between the i+1th peak and the ith peak; L i,i+1 represents the length of the i-th flexible unit; V f It represents the propagation speed of electromagnetic waves in the flexible distributed conductor.

4. The flexible strain sensor according to any one of claims 1 to 3, characterized in that: The controller determines the position and type of deformation of the flexible distributed conductor according to the reflected waveform and the baseline waveform, including: If the reflected waveform is the same as the baseline waveform, the controller determines that the flexible distributed conductor is not deformed; If the reflected waveform is different from the baseline waveform, the controller determines that the flexible distributed conductor is deformed.

5. The flexible strain sensor according to claim 4, characterized in that: If the reflected waveform is different from the baseline waveform, the controller determines that the flexible distributed conductor is deformed, including: If the time length of the reflected waveform is greater than the time length of the baseline waveform, the controller determines that the flexible distributed conductor is stretched and deformed; If the number of wave peaks of the reflected waveform is greater than the number of wave peaks of the baseline waveform, the controller determines that the flexible distributed conductor undergoes compression deformation.

6. The flexible strain sensor according to claim 5, characterized in that: If the reflected waveform is different from the baseline waveform, the controller determines that the flexible distributed conductor is deformed, including: If the time length of the reflected waveform is greater than the time length of the baseline waveform, and the number of peaks on the reflected waveform is the same as the number of peaks on the baseline waveform, the controller determines that tensile deformation has occurred and compressive deformation has not occurred; If the time length of the reflected waveform is equal to the time length of the baseline waveform, and the number of peaks on the reflected waveform is greater than the number of peaks on the baseline waveform, the controller determines that the flexible distributed conductor has not undergone tensile deformation but has undergone compressive deformation; If the time length of the reflected waveform is greater than the time length of the baseline waveform, and the number of peaks on the reflected waveform is greater than the number of peaks on the baseline waveform, the controller determines that the flexible distributed conductor undergoes tensile deformation and compressive deformation.

7. The flexible strain sensor according to claim 5 or 6, characterized in that: After the controller determines that the flexible distributed conductor is stretched and deformed, the method further includes: The controller determines the time difference between each peak on the reflected waveform and the previous and adjacent peak, and redetermines the length of each flexible unit; determines the flexible unit that has undergone stretching deformation based on the length difference between each flexible unit and the initial length; determines the time difference between each peak on the reflected waveform and the peak at the starting end, and locates the position of the flexible unit that has undergone stretching deformation.

8. The flexible strain sensor according to claim 5 or 6, characterized in that: If the reflected waveform is different from the baseline waveform, the controller determines that the flexible distributed conductor is deformed, including: If the number of peaks on the reflected waveform is K more than the number of peaks on the baseline waveform, the controller determines that compression deformation occurs at K positions of the flexible distributed conductor, where K is a positive integer.

9. The flexible strain sensor according to claim 8, characterized in that: If the reflected waveform is different from the baseline waveform, the controller determines that the flexible distributed conductor is deformed, including: If the time difference between two consecutive peaks on the reflection waveform is less than the time length of the baseline unit on the corresponding baseline waveform, then there is a peak between the two peaks corresponding to the compression deformation.

10. The flexible strain sensor according to claim 4, characterized in that: If the reflected waveform is different from the baseline waveform, the controller determines that the flexible distributed conductor is deformed, including: If the number of peaks of the reflected waveform is less than the number of peaks of the baseline waveform, and / or the time length of the reflected waveform is less than the time length of the baseline waveform, the controller determines that the flexible distributed conductor is broken.

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