Wearable soft tissue Young modulus monitoring device, system and method

Abstract

The invention discloses a wearable soft tissue Young modulus monitoring device which comprises a pressure applying mechanism, a contact radius sensor, a contact force sensor and a wearable mechanism. The pressure applying mechanism comprises a pressure head with a hemispherical pressure head contact surface; the contact radius sensor comprises a flexible pressure sensing array which is arranged on the pressure head contact surface and can reflect pressure distribution in the height direction of the pressure head; the contact radius sensor is further configured to output a first electric signal in response to the contact pressure when the pressure head contact surface is in contact with the tested soft tissue; and the contact force sensor is arranged on the pressure applying mechanism and is configured to respond to the contact pressure provided by the pressure applying mechanism when the pressure head contact surface is in contact with the tested soft tissue and output a second electric signal. Furthermore, the invention also discloses a corresponding monitoring system and a corresponding monitoring method. According to the invention, accurate, continuous and dynamic monitoring of the soft tissue Young modulus can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical engineering, and in particular relates to a wearable soft tissue Young's modulus monitoring device, a monitoring system and a monitoring method. Background Art

[0002] Palpation is a typical traditional method for testing the hardness of soft tissues. For example, clinicians can subjectively judge the change in hardness of the diseased tissue by pressing the diseased tissue with their fingers, thereby judging the progression of the disease. However, this method is highly subjective, lacks quantitative indicators, and cannot achieve continuous dynamic monitoring. Some traditional mechanical hardness testing systems, such as universal tensile testing machines, calculate the Young's modulus of the object by recording the curve of the deformation of the object being tested as it changes with the external force. However, these systems rely on large hardware equipment and require the object to have a standard shape and size, and cannot achieve quantitative and dynamic monitoring of the modulus of human soft tissues. Elastic ultrasound imaging reflects the modulus of the object by analyzing the deformation of the object when it is compressed or the propagation speed of the wave in the object. Although this type of technology can make the device handheld or wearable to support dynamic detection, it is limited by complex factors such as the influence of tissue heterogeneity and thickness and high operator dependence. Generally, it can only provide relative modulus reference values, and there are still great challenges in accurately providing its absolute value. The indentation method based on contact mechanics theory such as the Hertz model can calculate the Young's modulus of the object being measured by detecting the pressure and the indentation depth / contact radius generated when a hemispherical probe is pressed into the soft object. This calculation process does not require the object to have a standard shape and size, which has led to the rapid development and widespread application of related technologies such as atomic force microscopy and nanoindentation. However, indentation testing requires accurate force, displacement control and feedback systems, so it is generally limited to large hardware facilities and cannot achieve dynamic and continuous monitoring of human soft tissues.

[0003] The Chinese patent application with publication number CN115500811A proposes a tactile sensor with dual closed-loop control and a control method thereof, wherein the tactile sensor includes a dual closed-loop control system, a sensor measurement system and a tactile sensor system model, the dual closed-loop control system further includes a sensor contact, an amplitude stabilization control system and a frequency tracking system, the sensor measurement system further includes a pressing device and a resonance frequency acquisition system, and the tactile sensor system model is derived based on the control model of the tactile sensor and the equivalent acoustic impedance when the sensor contact touches the tissue to be measured, and is used to calculate the elasticity of the tissue to be measured based on the frequency offset of the self-excited oscillation circuit frequency tracking. The system can improve the measurement accuracy, reduce the system resonance frequency, and avoid invasive damage to the tissue to be measured. However, the system needs to control the contact force and stable contact state well when in use, and needs to use the dual closed-loop control system in coordination, the structure is complex, and continuous monitoring is not supported.

[0004] The Chinese patent application with publication number CN116685839A proposes a modulus sensor, which includes a base, a sensor, a pressure head and a locking device. The sensor is fixedly connected to the base; the pressure head is slidably connected to the base to move relative to the base in the axial direction in response to the first abutment between the pressure head and the material surface, so that the pressure head provides thrust to the sensor in the axial direction; the locking device is configured to releasably lock the pressure head in a locked state in response to the second abutment between the base and the material surface, wherein the pressure head in the locked state is prevented from moving in the axial direction relative to the base. Based on this device, when the thrust is continuously applied, the pressure head is locked at a certain position by the locking device, and the thrust and pressure head displacement at this time are measured by the sensor, and the Young's modulus is calculated according to the Hertz model. However, this device needs to construct a locking mechanism, the structure is complex, and continuous and dynamic monitoring cannot be achieved.

[0005] In summary, the existing soft tissue Young's modulus monitoring technology still faces great challenges in achieving continuous, dynamic and accurate monitoring at the same time. Summary of the invention

[0006] In view of this, the present invention provides a wearable soft tissue Young's modulus monitoring device, system and method, which are based on the Hertz contact model, utilize flexible tactile sensing technology, and combine the contact force and contact radius dual-modal detection scheme to achieve accurate, continuous and dynamic monitoring of soft tissue Young's modulus.

[0007] The first aspect of the present invention discloses a wearable soft tissue Young's modulus monitoring device, comprising a pressure mechanism, a contact radius sensor, a contact force sensor and a wearable mechanism; the pressure mechanism comprises a pressure head, and the pressure head is constructed to have a hemispherical pressure head contact surface; the wearable mechanism is used to carry the pressure mechanism and enable the pressure head contact surface to contact with the soft tissue to be measured when it is worn; the contact radius sensor comprises a flexible pressure sensing array arranged on the pressure head contact surface and capable of reflecting the pressure distribution in the height direction of the pressure head; the contact radius sensor is also constructed to output a first electrical signal in response to the contact pressure when the pressure head contact surface contacts the soft tissue to be measured; the contact force sensor is arranged on the pressure mechanism and is constructed to output a second electrical signal in response to the contact pressure provided by the pressure mechanism when the pressure head contact surface contacts the soft tissue to be measured.

[0008] As an optional solution, the flexible pressure sensing array has at least one group, and the flexible pressure sensing array includes a plurality of sensing units that can reflect the pressure distribution in the height direction of the pressure head.

[0009] As an optional solution, the flexible pressure sensing array has more than two groups, and the extension lines of one end of each flexible pressure sensing array intersect at the center point of the hemispherical pressure head contact surface.

[0010] As an optional solution, the flexible pressure sensing array has a plurality of groups arranged at equal intervals or with equal arc lengths along the pressure head height direction.

[0011] As an optional solution, the flexible pressure sensing array has a plurality of sensing units distributed along the circumference of the hemispherical pressure head contact surface.

[0012] As an optional solution, the pressure mechanism further includes an extension column fixedly connected to or integrally formed with the pressure head; the contact force sensor is arranged at an end of the extension column away from the pressure head.

[0013] As an optional solution, the wearable mechanism includes a shell and a strap connected to the shell; a through hole is opened on the shell; the pressure mechanism is arranged inside the shell, and its hemispherical pressure head contact surface extends out of the shell through the through hole.

[0014] As an optional solution, the first surface of the contact force sensor is in contact with the pressure mechanism, and the second surface opposite to the first surface is in contact with the inner surface of the shell.

[0015] As an optional solution, the monitoring device also includes a limiting mechanism; the extended column is a cylindrical structure, and the diameter of the cylinder is equal to the diameter of the hemispherical pressure head contact surface of the pressure head; the limiting mechanism is used to prevent the pressure mechanism from detaching from the shell through the through hole.

[0016] As an optional solution, the limiting mechanism is a wing that protrudes laterally and is arranged at the connection between the pressure head and the extension body, or is a limiting member arranged on the pressure mechanism.

[0017] As an optional solution, the wearable mechanism is a strap; when the pressure head contacts the soft tissue to be measured, the strap contacts the contact force sensor.

[0018] As an optional solution, the contact radius sensor is an ionization sensor.

[0019] As an optional solution, the contact force sensor is a piezoresistive sensor.

[0020] As an optional solution, the monitoring device further comprises a data acquisition module which is communicatively connected to the host computer; the contact radius sensor and the contact force sensor are electrically connected to the data acquisition module via wires respectively.

[0021] A second aspect of the present invention discloses a wearable soft tissue Young's modulus monitoring system, comprising a host computer, and a wearable soft tissue Young's modulus monitoring device according to any one of the first aspects of the present invention;

[0022] Alternatively, the device comprises a host computer, a data acquisition device, and the wearable soft tissue Young's modulus monitoring device according to any one of the first aspects of the present invention; the data acquisition device is communicatively connected to the host computer; the contact radius sensor and the contact force sensor are electrically connected to the data acquisition device through wires respectively;

[0023] The host computer includes a computing module, a storage module and a communication module. The computing module is constructed to call a program pre-stored in the storage module and execute the following instructions: obtain the first electrical signal and the second electrical signal received by the communication module; calculate the contact radius between the indenter contact surface and the soft tissue to be measured according to the first signal; convert the second electrical signal into a contact force between the indenter contact surface and the soft tissue to be measured; and calculate the equivalent Young's modulus value of the soft tissue to be measured based on the Hertz formula and the contact radius and contact force.

[0024] A third aspect of the present invention discloses a wearable soft tissue Young's modulus monitoring method, comprising:

[0025] When the pressure head contact surface of the pressure mechanism contacts the soft tissue to be measured, the flexible pressure sensing array in the contact radius sensor responds to the contact pressure and outputs a first electrical signal; the pressure head contact surface is hemispherical; the flexible pressure sensing array is arranged on the pressure head contact surface and can reflect the pressure distribution in the height direction of the pressure head;

[0026] Calculating the contact radius between the indenter contact surface and the measured soft tissue according to the first electrical signal;

[0027] Acquiring a second electrical signal output by the contact force sensor in response to the contact pressure provided by the pressure mechanism when the pressure head contact surface of the pressure mechanism contacts the soft tissue being measured; the contact force sensor is arranged on the pressure mechanism;

[0028] converting the second electrical signal into a contact force between the indenter contact surface and the measured soft tissue;

[0029] Based on the Hertz formula and the contact force and contact radius, the equivalent Young's modulus value of the measured soft tissue is calculated.

[0030] As an optional solution, when the flexible pressure sensing array includes a plurality of sensing units capable of reflecting the pressure distribution in the height direction of the pressure head, the contact radius between the pressure head contact surface and the measured soft tissue is calculated according to the first electrical signal, specifically including:

[0031] Counting the number of sensing units in the flexible pressure sensing array whose first electrical signals outputted are greater than a set threshold;

[0032] The contact radius between the indenter contact surface and the measured soft tissue is calculated based on the number and the position of the sensor unit.

[0033] As an optional solution, when the flexible pressure sensing array has multiple groups, the equivalent Young's modulus value of the measured soft tissue is calculated based on the Hertz formula and the contact force and contact radius, specifically including:

[0034] The contact radius corresponding to each group of flexible pressure sensing arrays is averaged, and the obtained average value is used as the total contact radius between the indenter contact surface and the measured soft tissue;

[0035] Based on the Hertz formula and the contact force and the total contact radius, the equivalent Young's modulus value of the measured soft tissue is calculated.

[0036] As an optional solution, when the extension line of one end of the flexible pressure sensing array coincides with the center point of the hemispherical pressure head contact surface, and there is a sensing blind area in the center point area of ​​the hemispherical pressure head contact surface, and the flexible pressure sensing array has a row of sensing units with equal arc length distribution in the pressure head height direction, the contact radius between the pressure head contact surface and the measured soft tissue is calculated as follows:

[0037]

[0038] Where N is the number of sensing units whose first electrical signal is greater than the set threshold, R is the radius of the pressure head, and L is B is the arc length of the sensing blind area, D R is the distance between adjacent sensor units.

[0039] As an optional solution, when the flexible pressure sensing array includes multiple groups arranged at equal intervals or equal arc lengths along the height direction of the pressure head, and when the flexible pressure sensing array has multiple sensing units arranged in an array, calculating the contact radius between the pressure head contact surface and the measured soft tissue according to the first electrical signal specifically includes:

[0040] Calculating an average value of first electrical signals corresponding to each sensing unit in the flexible pressure sensing array;

[0041] Counting the number of first electrical signal average values ​​greater than a first set threshold;

[0042] The contact radius between the indenter contact surface and the measured soft tissue is calculated based on the number and the position of the flexible pressure sensing array.

[0043] The present invention has the following beneficial effects:

[0044] (1) The present invention realizes synchronous and continuous detection of the contact force and contact radius between the pressure head and the soft tissue to be measured in a wearable manner by means of contact force sensors respectively arranged on the pressure-applying mechanism and contact radius sensors composed of a flexible pressure sensor array attached to the contact surface of the pressure head of the pressure-applying mechanism. Moreover, based on this wearable manner, it is no longer required that the object to be measured is in a static state, thereby realizing wearable continuous and dynamic monitoring of the Young's modulus of soft tissue.

[0045] (2) The present invention realizes high-precision detection of contact radius through a flexible pressure array sensor with high spatial resolution and low detection limit. In particular, the use of a contact radius sensor based on the ionization principle makes it easier to achieve low threshold response and high spatial resolution arrangement of the sensor units in the sensor array, thereby realizing accurate monitoring of the tissue Young's modulus.

[0046] (3) The present invention provides a variety of design schemes for the contact radius sensor, which can be selected according to actual needs.

[0047] (4) The present invention is expected to assist in the quantitative assessment of disease progression, monitor soft tissue function during daily activities, optimize athletic performance, avoid sports injuries, and provide a quantitative basis for rehabilitation training. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 It is a schematic diagram of the three-dimensional structure of a wearable soft tissue Young's modulus monitoring device;

[0049] Figure 2 A bottom view of a wearable soft tissue Young's modulus monitoring device;

[0050] Figure 3 It is a front view of a wearable soft tissue Young's modulus monitoring device;

[0051] Figure 4 AA cross-sectional view of the wearable soft tissue Young's modulus monitoring device;

[0052] Figure 5 BB cross-section diagram of the wearable soft tissue Young's modulus monitoring device;

[0053] Figure 6 It is the CC cross-section diagram of the wearable soft tissue Young's modulus monitoring device;

[0054] Figure 7 DD cross-sectional view of the wearable soft tissue Young's modulus monitoring device;

[0055] Figure 8 This is a schematic diagram of the internal structure shell of the wearable soft tissue Young's modulus monitoring device;

[0056] Fig. 9It is the expansion schematic diagram of the contact radius sensor;

[0057] Fig.10 (a), (b), (c), and (d) are schematic diagrams of other structures in the contact radius sensor;

[0058] Fig.11 This is a schematic diagram of the system working principle;

[0059] Fig.12 This is a schematic diagram of the contact radius calculation principle;

[0060] Fig.13 It is a schematic diagram of the test status;

[0061] Fig.14 (a), (b), and (c) are schematic diagrams of the curves of the contact force, contact radius, and tissue Young's modulus of the soft tissue at the back of the calf changing with time during the process of climbing stairs.

[0062] Drawing annotations: 1-pressure head, 101-pressure head contact surface, 102-pressure head top surface, 2-contact radius sensor, 201-sensing unit, 3-contact force sensor, 4-housing 4, 401-base, 402-top cover, 403-screw hole, 404-wire outlet, 405-binding strap groove (405a, 405b, 405c), 5-extension column, 6-wing, 7-wire, 8-binding strap. DETAILED DESCRIPTION

[0063] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments and drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] In the description of the present invention, if there are terms indicating orientation or positional relationship such as "upper", "lower", "front", "back", "inside", "outside", etc., they are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in combination with specific circumstances. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, but may include other units that are not clearly listed or inherent to these products or devices.

[0065] In the drawings of the embodiments provided by the present invention, the connection relationship between modules or components indicates that there is a communication connection between them, which can be specifically implemented as one or more communication buses or signal lines. Those skilled in the art can understand and implement it without creative work.

[0066] Combination Figures 1 to 14 As shown, the embodiment of the present invention provides a wearable soft tissue Young's modulus monitoring device (hereinafter referred to as "monitoring device") which is mainly used for data collection related to soft tissue Young's modulus calculation, and is composed of a pressure head 1, a contact radius sensor 2, a contact force sensor 3, a shell 4, an extension column 5, a wire 7, a strap 8, etc. Among them, the shell 4 and the strap 8 together form a wearable mechanism for carrying the pressure head 1, the contact radius sensor 2, the contact force sensor 3 and the extension column 5 and other structures. When in use, the monitoring device is fixed to the soft tissue area to be measured through the wearable mechanism, and the pressure head contact surface of the pressure mechanism is in contact with the soft tissue to be measured, thereby realizing continuous dynamic monitoring of the Young's modulus of the soft tissue to be measured.

[0067] like Figure 1 As shown, the housing 4 can specifically adopt a rectangular box structure consisting of a base 401 and a top cover 402. The base 401 and the top cover 402 are both provided with screw holes 403 at corresponding positions, and the two can be fixedly connected by screws set in the screw holes 403. In other embodiments, the two can also be fixedly connected by other detachable methods such as hinges and snap connections. A circular through hole with a diameter that is compatible with the diameter of the pressure head 1 is provided on the bottom surface of the base 401. A wire outlet 404 for passing the wire 7 is provided on the side wall of the top cover 402. A plurality of strap grooves 405 for passing the straps 8 are also provided on the base 401 and the top cover 402.

[0068] When the base 401 and the top cover 402 of the housing 4 are separated, the pressure head 1 attached with the contact radius sensor 2 and the extension column 5 attached with the contact force sensor 3 can be assembled into the base 401 of the housing 4. The pressure head 1 and the extension column 5 can be formed in one piece or fixedly connected by gluing or the like. Figure 6As shown, there is a wing 6 protruding laterally at the connection between the pressure head 1 and the extension column 5. Its shape in the top view direction matches the base 401 of the shell 4, and is approximately an isosceles triangle with a vertex angle of 90 degrees. It has a certain thickness along the long axis direction of the extension column, such as 1mm thick. This thickness ensures that it has the necessary mechanical strength and can prevent the pressure head 1 from sliding infinitely out of the base 401 of the shell 4 along the long axis of the extension column 5. In other embodiments, other methods can also be used to limit the pressure head 1 from sliding infinitely out of the shell base 401. For example, by setting a limiting mechanism at the corresponding position of the side wall of the pressure head 1 or the extension column 5, or by designing the internal structure of the shell 4 to achieve post-assembly limiting, or directly designing the extension column 5 as a square column with a side length of 2R, in which case there is no need to set a limiting mechanism. After assembly, after the base 401 and the top cover 402 of the shell 4 are combined, screw the screws into the screw holes 403 to fix them.

[0069] The strap 8 is mainly used to fix the housing 4. Specifically, the strap 8 is fixed to the housing 4 through the strap slot 405, and is used to subsequently fix the monitoring device to the human tissue. Specifically, the strap 8 is inserted into the strap slot 405b and exits from the strap slot 405c. After the length is adjusted until the pressure head 1 is completely pressed into the soft tissue to be measured, the two free ends of the strap 8 are cross-fixed above the top cover 402. In other embodiments, the fixing method of the strap 8 can be freely adjusted, such as inserting from the strap slot 405a and then exiting from the strap slot 405b. As long as the pressure head 1 can be completely pressed into the soft tissue to be measured and does not loosen without human intervention, it will be fine.

[0070] Among them, the pressure head 1 is a hemispherical structure, including a hemispherical pressure head contact surface 101 and a pressure head top surface 102 connected to the pressure head contact surface 101, and the pressure head top surface 102 is a circular plane. The distance D between the center point of the pressure head contact surface 101 and the pressure head top surface 102 is just equal to the radius R of the pressure head. The extension cylinder 5 is usually a cylindrical structure, and the diameter of the cylinder is equal to the diameter (2R) of the pressure head top surface 102. The extension cylinder 5 is connected to the pressure head 1 (pressure head top surface 102) downward and connected to the contact force sensor 3 upward. It can be understood that for soft tissue containing muscles, the pressing depth is usually greater than the pressure head radius. By using the extension cylinder 5, it can be adapted to the monitoring of different soft tissues and expand the scope of application. The pressure head 1 and the extension cylinder 5 are formed in one piece, and the formed whole can be called a pressure mechanism. In other embodiments, the pressure head 1 and the extension column 5 may also be fixedly connected by bonding or the like; or, the pressure-applying mechanism may be just a pressure head having a hemispherical pressure head contact surface; or, the pressure-applying mechanism may be other structures having a hemispherical pressure head contact surface.

[0071] It should be noted that in this embodiment, the distance from the top of the pressure head to the bottom of the pressure head is exactly equal to the pressure head radius, or more accurately, the chord height of the hemispherical pressure head contact surface is equal to the hemispherical radius. In other embodiments, the height of the pressure head top from the pressure head bottom may be less than the pressure head radius or greater than the pressure head radius, which is an approximate hemispherical structure, but this type of structure is still classified as a hemispherical structure in the present invention. In other words, the hemispherical shape defined in the present invention can be a standard hemispherical shape or a non-standard approximate hemispherical shape, and accordingly, the hemispherical structure can be a standard hemispherical structure or an approximate hemispherical structure.

[0072] The contact radius sensor 2 is mainly composed of one or more groups of flexible pressure sensing arrays that can be attached to the surface of the pressure head contact surface 101 through adhesives such as double-sided adhesive, instant adhesive, hot melt adhesive, etc. Each group of flexible pressure sensing arrays includes a number of pressure sensing units 201. It can be understood that the higher the spatial resolution of the sensing unit 201, the higher the calculation accuracy; the smaller the width of the contact radius sensor 2, the better the attachment to the pressure head contact surface 101, and the less likely it is to cause signal noise generated during attachment. After the wires of each group of sensor arrays are merged, they are led out from the outlet 404 opened on the shell 4 so as to be electrically connected to the data acquisition device.

[0073] The lower surface of the contact force sensor 3 is attached to the top of the extension column 5 by adhesives such as double-sided adhesive, instant adhesive, hot melt adhesive, etc., and the upper surface is in contact with the shell 4. The contact force sensor 3 is consistent with the surface shape and size of the extension column 5, and is also a circle with a radius of R, just completely covering the surface of the extension column 5. In other embodiments, the contact force sensor 3 is not required to be completely consistent with the surface shape and size of the extension column 5. For example, it can be a circle with a radius less than R, or a rectangle inscribed in the surface of the extension column 5. The contact force sensor 3 is connected to the data acquisition device through the wire 7 to achieve signal output. The wire 7 can also be led out from the outlet 404 opened on the shell 4, or it can be first merged with the wire connected to the contact radius sensor 2 and then led out through the outlet 404.

[0074] The present invention does not impose any special restrictions on the sensing principle of the contact force sensor 3 and the contact radius sensor 2. They can be based on piezoresistive, capacitive, ionization, optical fiber and other principles. The materials of the electrode layer and the functional layer are not limited as long as they can ensure that pressure sensing can be achieved. In this embodiment, the contact radius sensor 2 is based on the ionization sensing principle, and the flexible pressure sensing array it contains is mainly composed of electrodes, functional layers and packaging layers, wherein the electrode layer is obtained by processing copper foil on a flexible PI substrate, and the functional layer is a flexible, conductive ion membrane, which is mainly made of a mixture of thermoplastic polyurethane elastomer (TPU), ionic liquid, and indium tin oxide (ITO), and the packaging layer uses a flexible PU material. In a preferred embodiment, the contact radius sensor includes more than two groups of flexible pressure sensing arrays, and the extension line of one end of each group of flexible pressure sensing arrays intersects at the center point of the pressure head contact surface, and the other end is output after merging with other flexible pressure sensing arrays through a wire, and the overall arc distribution is equal to the center point of the hemispherical pressure head contact surface. The length L of each set of flexible pressure sensor arrays covers the hemispherical surface of the pressure head as much as possible, and the width W is generally not greater than 3 mm; each set of flexible pressure sensor arrays includes a number of sensor units arranged at equal intervals (equal intervals after unfolding, that is, equal intervals in the arc direction), and the interval D between adjacent sensor units R Less than 1mm. Figure 2 As shown, the arc length between the bottom end of the flexible pressure sensing array and the center point of the pressure head contact surface 101 is L B The sensing blind area is 1mm. It is understandable that in actual use, the pressure in the sensing blind area is generally not 0, so the sensing unit may not be deployed here. When in use, at the position where the pressure head 1 (pressure head contact surface 101) contacts the soft tissue to generate pressure, the functional layer material of the contact radius sensor 2 is deformed, the capacitance value or impedance value of the sensing unit changes, and a first electrical signal is output. This first electrical signal is received by the data acquisition device and transmitted to the host computer. The host computer calculates the contact radius by counting the number of sensing units whose first signal is greater than the set threshold.

[0075] It is worth noting that the contact radius sensor adopts the ionization principle because compared with other types of sensors, the ionization sensor has higher sensitivity and lower detection limit, and can generate the first electrical signal under relatively small pressure (less than 1kpa), which is conducive to capturing the tiny pressure signal at the contact edge of the pressure head 1 and the soft tissue being measured. At the same time, benefiting from the high sensitivity of the ionization sensor, the lower pressure signal can also be captured by the smaller-sized sensor unit, so the spatial density (resolution) of the sensor array can be higher, further ensuring the high accuracy of the contact radius sensor.

[0076] Taking one group of flexible pressure sensor arrays as an example, when some of the sensor units in the flexible pressure sensor array are subjected to pressure, the first electrical signal (such as capacitance value) output by the sensor unit changes. After the first electrical signal is transmitted to the host computer through the data acquisition device, the host computer counts the number N of sensor units whose first electrical signal exceeds the set threshold, and calculates the contact radius R c , the calculation formula is as follows:

[0077] R C =R*sinθ (1)

[0078] in,

[0079] The contact radius formula is as follows:

[0080]

[0081] Where θ is the arc of the contact area, R is the radius of the indenter 1, that is, the radius of the hemispherical indenter contact surface 101, and L B is the arc length of the sensing blind area, D R is the distance between adjacent sensor units.

[0082] Considering that the angle between the monitoring device and the soft tissue being measured may change during dynamic activities, the R calculated by the four sensor arrays can be C The values ​​are averaged, and the average contact radius is used as the final total contact radius to participate in the calculation of Young's modulus to reduce the calculation error caused by the skew of the monitoring device.

[0083] It is worth noting that the present invention does not impose any particular limitation on the arrangement of the flexible pressure sensing array. Fig.10 Several optional layouts are provided. Fig.10 The arrangement of the flexible pressure sensing arrays in (a) is similar to that in the aforementioned embodiment, and each flexible pressure sensing array is distributed in equal arcs about the center point of the hemispherical pressure head contact surface, but the arc is smaller, for example, 45 degrees; Fig.10 (b) The angles between each flexible pressure sensing array and the horizontal plane are equal and less than 90 degrees, both ends of the flexible pressure sensing array are close to the top surface of the pressure head, and one end is connected to other flexible pressure sensing arrays through wires for output; Fig.10 In (c), each flexible pressure sensing array is designed as a quasi-circular ring (with a notch on the circular ring), one end of the quasi-circular ring is connected to other flexible pressure sensing arrays through a wire and then output, the projection of the center of the quasi-circular ring on the horizontal plane coincides with the center point of the pressure head contact surface, and each flexible pressure sensing array is arranged at equal intervals in the pressure head height direction, or the arc lengths of adjacent flexible pressure sensing arrays along the pressure head height direction are equal; Fig.10In (d), the angle between each flexible pressure sensing array and the horizontal plane is equal to 90 degrees, and both ends of the flexible pressure sensing array are close to the top surface of the pressure head. It can be seen that as long as the flexible pressure sensing array itself or the arrangement of the sensing units in the flexible pressure sensing array can reflect the pressure distribution in the height direction of the pressure head. It can be understood that these embodiments can be divided into two categories. One category is to reflect the pressure distribution in the height direction of the pressure head through the sensing units inside the flexible pressure sensing array, that is, Fig.10 (a) Fig.10 (b) Fig.10 (d) As shown; the arrangement of the sensing units in another type of flexible pressure sensing array cannot reflect the pressure distribution in the direction of the pressure head height, but reflects the pressure distribution in the direction of the pressure head height through the arrangement of multiple groups of flexible pressure sensing arrays, that is, Fig.10 (c). The first electrical signal output by the flexible pressure sensing array actually refers to the electrical signal output by each sensing unit, that is, the first electrical signal output by the contact radius sensor actually includes multiple signals arranged in sequence. For these distribution designs, the host computer can know the position of each flexible pressure sensing array or sensing unit based on the known arrangement method or sequence, count whether the first electrical signal is greater than the set threshold, and then calculate the contact radius.

[0084] In this embodiment, the contact force sensor 3 is based on the piezoresistive principle and is mainly composed of an electrode layer, a functional layer, and a packaging layer, wherein the electrode layer is obtained by processing copper foil on a polyimide (PI) substrate, the functional layer is composed of a conductive polyethylene (PE) film, the packaging layer is composed of a polyurethane film (PU), and the electrode layer is electrically connected to the data acquisition device through a wire 7. When the indenter contact surface 101 of the indenter 1 contacts the soft tissue to be measured, a contact pressure is generated, and the contact pressure is transmitted upward to the contact force sensor 3 through the extension cylinder 5, so that the functional layer material of the contact force sensor 3 is deformed to produce a piezoresistance change, and the output second electrical signal is received by the data acquisition device and transmitted to the host computer, and the host computer converts the second electrical signal into a corresponding contact force value. When the Young's modulus of the soft tissue to be measured changes dynamically, such as muscle contraction and relaxation, the contact pressure between the indenter 1 and the soft tissue to be measured changes continuously, which can be converted into a continuous real-time contact force F. It is worth noting that the contact force sensor 3 adopts the piezoresistive principle because the existing piezoresistive materials are mature in application, stable in nature, have high accuracy, linearity, and repeatability, and can accurately capture the contact force between the pressure head 1 and the soft tissue being measured.

[0085] In a specific application example, the radius R of the pressure head 1 and the extension cylinder 5 is set to 8 mm, and the height of the extension cylinder 5 is set to 16 mm. The contact radius sensor 2 includes four groups of pressure sensing arrays, each of which contains 28 sensing units. The space width W of the pressure sensing array after expansion is set to 2 mm, the length L is 11.6 mm, and the thickness is 0.5 mm; the distance D between adjacent sensing units is R (i.e. spatial resolution) is set to 0.4 mm, and the arc length L of the sensing blind area B The radius of the contact force sensor 3 is set to 8 mm, and the thickness is set to 0.25 mm. The housing 4 is a rectangular box structure, and the height, length, width, and wall thickness of the rectangular box are set to 10 mm, 26 mm, 26 mm, and 3 mm, respectively. The shape and size of each strap groove 405 on the housing 4 are consistent, the length is set to 16 mm, and the width is set to 2 mm.

[0086] It is worth noting that in actual use, the above dimensions can be flexibly adjusted according to needs, such as the radius of the pressure head 1 and the extension cylinder 5 can be any size greater than 0; the spatial size of the pressure sensing array of the contact radius sensor 2 can be flexibly adapted according to the radius of the pressure head 1, and the spatial resolution can be flexibly adjusted according to the requirements of detection accuracy; the height of the extension cylinder 5 can be adjusted according to the tissue thickness and detection requirements. When the height of the extension cylinder 5 is a negative value, it means that the height of the pressure head is less than its radius; the radius of the contact force sensor 3 can be any value greater than 0, generally not greater than the radius of the extension cylinder 5, and the thickness can be any value greater than 0; the size of the shell 4 can be flexibly adjusted according to the size of the pressure head 1 and the wing 6; the length and width of the strap groove 405 can be flexibly adjusted according to the size of the shell 4.

[0087] In this embodiment, the pressure head 1, the extension cylinder 5 and the shell 4 can be obtained by 3D printing of resin materials, and the bandage 8 is made of nylon material. However, it can be understood that the present invention does not limit the material type of the pressure head 1, the extension cylinder 5 and the shell 4. It can be understood that the material hardness is significantly higher than the soft tissue to be measured. Common choices include ceramics, glass, carbon fiber materials, polymers and other high modulus composite materials. In addition, the pressure head 1 and the shell 4 can be made of different materials or the same material. The bandage 8 can also be made of nylon, polydimethylsiloxane (PDMS), silicone, polyurethane, rubber, spandex, polyester fiber, leather and its artificial products, etc., generally in the form of fabric, to ensure that it has both a certain strength and the necessary softness.

[0088] The shape of the shell 4 in the present invention can be in various forms, such as a cylinder, or a box structure with rounded corners. The connection method between the shell 4 and the strap 8 can also be flexibly adjusted, and does not necessarily need to be connected through the strap groove 405. For example, it can be connected by snapping, bonding, etc. In other embodiments, the monitoring device may not be provided with a shell 4. For example, the strap 8 is directly covered on the top of the pressure mechanism (contact force sensor 3). However, this method may require calibration for specific application scenarios. For example, when simulating the monitoring device being fixed on the biceps brachii of the upper arm, pressure is applied to the top of the strap 8 through a calibration device (such as LCR), and the force value output by the calibration device and the second electrical signal output by the contact force sensor 3 are recorded at the same time. A fitting relationship between the two is established to obtain a calibration curve describing this fitting relationship for subsequent signal conversion.

[0089] Furthermore, the embodiment of the present invention also discloses a wearable soft tissue Young's modulus monitoring system (hereinafter referred to as "monitoring system"), which is mainly composed of a wearable soft tissue Young's modulus monitoring device, a data acquisition device and a host computer, wherein the monitoring device can adopt the structure described in the above embodiment. The data acquisition device mainly includes an electrical signal acquisition circuit and a communication module, which is electrically connected to the wearable soft tissue Young's modulus monitoring device through a wire, and is mainly used for the collection and transmission of electrical signals. The data acquisition device can also be worn on the human body, and the spatial distance between it and the monitoring device is generally within 10 to 30 cm. In a specific application example, the soft tissue to be measured is the biceps brachii of the upper arm, and the data acquisition device can be fixed above the shoulder or back by tape or straps, or it can be fixed to the waist by a belt. Among them, the data acquisition device can realize communication with the host computer by Bluetooth, wireless transmission, etc., and correspondingly, the communication module can be a Bluetooth module, a WIFI module, etc.

[0090] In another embodiment, the present invention can also be based on the monitoring device described in the above embodiment, and a data acquisition module can be directly integrated in the housing 4 as a component of the monitoring device. In this case, the housing 4 does not need to be provided with an outlet 404, and the contact radius sensor 2 and the contact force sensor 3 can be directly electrically connected to the data acquisition module inside the housing 4.

[0091] like Fig.13 As shown, during the test, the strap 8 is wrapped around the test part, and the shell 4 is pressed to make the shell base 401 fit with the skin surface. At this time, the pressure head 1 is completely pressed into the soft tissue to be tested, and then the strap 8 is fixed on the arm, thereby realizing continuous dynamic monitoring of the Young's modulus of the wearable soft tissue, that is, the first electrical signal and the second electrical signal can be continuously collected during any dynamic activity of the human body, and transmitted to the host computer through the data acquisition device, and the host computer calculates the contact force and contact radius between the pressure head 1 and the soft tissue to be tested. The curve of the change over time (such as Fig.14As shown in Figure 2), the equivalent Young's modulus of the soft tissue under test is calculated based on the Hertz contact model to obtain a curve of the equivalent Young's modulus changing with time. The calculation formula is as follows:

[0092]

[0093] Where, E represents the equivalent Young's modulus of the soft tissue under test; F represents the contact force, which is converted from the second electrical signal measured by the contact force sensor; R represents the radius of the indenter, which is a known quantity; v represents the Poisson's ratio of the soft tissue under test, which is set to be a known quantity of 0.45; R CA Represents the total contact radius between the soft tissue being measured and the indenter, which is calculated from the first electrical signal measured by the contact radius sensor.

[0094] It can be understood that the host computer in the present invention can be a mobile terminal device such as a smart phone, a smart watch, a smart bracelet, a tablet computer, a laptop computer, or a desktop computer, or a special terminal device in the medical field, as long as it can realize data processing and calculation functions. The host computer includes at least a computing module, a storage module and a communication module. The communication module can be connected to the data acquisition device by wireless communication, and receive the first electrical signal measured by the contact radius sensor 2 and the second electrical signal measured by the contact force sensor 3 sent by the data acquisition device. The computing module is a general and / or special processing module with various processing and computing capabilities, which can call the program pre-stored in the storage module and execute the corresponding instructions to realize the calculation process of Young's modulus.

[0095] Finally, it should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numerals in the claims should not be regarded as limiting the claims involved.

Claims

1. A wearable soft tissue Young's modulus monitoring device, characterized in that: It includes a pressure mechanism, a contact radius sensor, a contact force sensor and a wearable mechanism; The pressure mechanism includes a pressure head, and the pressure head is configured to have a hemispherical pressure head contact surface; The wearable mechanism is used to carry the pressure-applying mechanism and enable the contact surface of the pressure head to contact the soft tissue to be measured when the wearable mechanism is worn; The contact radius sensor comprises a flexible pressure sensing array arranged on the contact surface of the pressure head and capable of reflecting the pressure distribution in the height direction of the pressure head; The contact radius sensor is also configured to output a first electrical signal in response to contact pressure when the indenter contact surface contacts the soft tissue being measured; The contact force sensor is arranged on the pressure mechanism and is configured to output a second electrical signal in response to the contact pressure provided by the pressure mechanism when the pressure head contact surface contacts the soft tissue to be measured.

2. The monitoring device according to claim 1, characterized in that: The flexible pressure sensing array has at least one group, and the flexible pressure sensing array includes a plurality of sensing units that can reflect the pressure distribution in the height direction of the pressure head.

3. The monitoring device according to claim 2, characterized in that: The flexible pressure sensing array has more than two groups, and the extension lines of one end of each flexible pressure sensing array intersect at the center point of the hemispherical pressure head contact surface.

4. The monitoring device according to claim 1, characterized in that: The flexible pressure sensing array has a plurality of groups arranged at equal intervals or with equal arc lengths along the pressure head height direction.

5. The monitoring device according to claim 4, characterized in that: The flexible pressure sensing array has a plurality of sensing units distributed along the circumference of the hemispherical pressure head contact surface.

6. The monitoring device according to any one of claims 1 to 5, characterized in that: The pressure mechanism also includes an extension column fixedly connected to or integrally formed with the pressure head; the contact force sensor is arranged at one end of the extension column away from the pressure head.

7. The monitoring device according to any one of claims 1 to 5, characterized in that: The wearable mechanism includes a shell and a strap connected to the shell; a through hole is opened on the shell; the pressure-applying mechanism is arranged inside the shell, and its hemispherical pressure head contact surface extends out of the shell through the through hole.

8. The monitoring device according to claim 7, characterized in that: The first surface of the contact force sensor is in contact with the pressure mechanism, and the second surface opposite to the first surface is in contact with the inner surface of the shell.

9. The monitoring device according to claim 7, characterized in that: It also includes a limiting mechanism; the extended column is a cylindrical structure, and the diameter of the cylinder is equal to the diameter of the hemispherical pressure head contact surface of the pressure head; the limiting mechanism is used to prevent the pressure mechanism from detaching from the shell from the through hole.

10. The monitoring device according to claim 9, characterized in that: The limiting mechanism is a wing that protrudes laterally and is arranged at the connection between the pressure head and the extension body, or is a limiting member arranged on the pressure mechanism.

11. The monitoring device according to any one of claims 1 to 5, characterized in that: The wearable mechanism is a strap; When the pressure head contacts the soft tissue to be measured, the binding belt contacts the contact force sensor.

12. The monitoring device according to any one of claims 1 to 5, characterized in that: The contact radius sensor is an ionization type sensor.

13. The monitoring device according to any one of claims 1 to 5, characterized in that: The contact force sensor is a piezoresistive sensor.

14. The monitoring device according to any one of claims 1 to 5, characterized in that: It also includes a data acquisition module that is communicatively connected to the host computer; the contact radius sensor and the contact force sensor are electrically connected to the data acquisition module through wires respectively.

15. A wearable soft tissue Young's modulus monitoring system, characterized in that: It comprises a host computer and a wearable soft tissue Young's modulus monitoring device as claimed in any one of claims 1 to 14; Alternatively, it comprises a host computer, a data acquisition device, and the wearable soft tissue Young's modulus monitoring device according to any one of claims 1 to 13; the data acquisition device is communicatively connected to the host computer; the contact radius sensor and the contact force sensor are electrically connected to the data acquisition device through wires respectively; The host computer includes a computing module, a storage module and a communication module. The computing module is configured to call a program pre-stored in the storage module and execute the following instructions: Acquiring the first electrical signal and the second electrical signal received by the communication module; Calculating the contact radius between the indenter contact surface and the measured soft tissue according to the first signal; converting the second electrical signal into a contact force between the indenter contact surface and the measured soft tissue; Based on the Hertz formula and the contact radius and contact force, the equivalent Young's modulus value of the measured soft tissue is calculated.

16. A wearable soft tissue Young's modulus monitoring method, characterized in that: include: When the pressure head contact surface of the pressure mechanism contacts the soft tissue to be measured, the flexible pressure sensing array in the contact radius sensor responds to the contact pressure and outputs a first electrical signal; the pressure head contact surface is hemispherical; the flexible pressure sensing array is arranged on the pressure head contact surface and can reflect the pressure distribution in the height direction of the pressure head; Calculating the contact radius between the indenter contact surface and the measured soft tissue according to the first electrical signal; Acquiring a second electrical signal output by the contact force sensor in response to the contact pressure provided by the pressure mechanism when the pressure head contact surface of the pressure mechanism contacts the soft tissue being measured; the contact force sensor is arranged on the pressure mechanism; converting the second electrical signal into a contact force between the indenter contact surface and the measured soft tissue; Based on the Hertz formula and the contact force and contact radius, the equivalent Young's modulus value of the measured soft tissue is calculated.

17. The wearable soft tissue Young's modulus monitoring method according to claim 16, characterized in that: When the flexible pressure sensing array includes a plurality of sensing units capable of reflecting the pressure distribution in the height direction of the pressure head, the contact radius between the pressure head contact surface and the measured soft tissue is calculated according to the first electrical signal, specifically including: Counting the number of sensing units in the flexible pressure sensing array whose first electrical signals outputted are greater than a set threshold; The contact radius between the indenter contact surface and the measured soft tissue is calculated based on the number and the position of the sensor unit.

18. The wearable soft tissue Young's modulus monitoring method according to claim 17, characterized in that: When the flexible pressure sensing array has multiple groups, the equivalent Young's modulus value of the measured soft tissue is calculated based on the Hertz formula and the contact force and contact radius, specifically including: The contact radius corresponding to each group of flexible pressure sensing arrays is averaged, and the obtained average value is used as the total contact radius between the indenter contact surface and the measured soft tissue; Based on the Hertz formula and the contact force and the total contact radius, the equivalent Young's modulus value of the measured soft tissue is calculated.

19. The wearable soft tissue Young's modulus monitoring method according to claim 17 or 18, characterized in that: When the extension line of one end of the flexible pressure sensing array coincides with the center point of the hemispherical pressure head contact surface, and there is a sensing blind area in the center point area of ​​the hemispherical pressure head contact surface, and the flexible pressure sensing array has a row of sensing units with equal arc length distribution in the pressure head height direction, the contact radius between the pressure head contact surface and the measured soft tissue is calculated as follows: Where N is the number of sensing units whose first electrical signal is greater than the set threshold, R is the radius of the pressure head, and L is B is the arc length of the sensing blind area, D R is the distance between adjacent sensor units.

20. The wearable soft tissue Young's modulus monitoring method according to claim 16, characterized in that: When the flexible pressure sensing array includes a plurality of groups arranged at equal intervals or equal arc lengths along the height direction of the pressure head, and when the flexible pressure sensing array has a plurality of sensing units arranged in an array, calculating the contact radius between the pressure head contact surface and the measured soft tissue according to the first electrical signal specifically includes: Calculating an average value of first electrical signals corresponding to each sensing unit in the flexible pressure sensing array; Counting the number of first electrical signal average values ​​greater than a first set threshold; The contact radius between the indenter contact surface and the measured soft tissue is calculated based on the number and the position of the flexible pressure sensing array.

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