Flexible conformal piezoelectric multi-dimensional force sensor

Abstract

The application discloses a flexible conformal piezoelectric multidimensional force sensor, and relates to the technical field of sensors and measurement and control, which comprises a sensor and a readout circuit, the sensor comprises a piezoelectric film and an electrode surface array arranged on the piezoelectric film, in the electrode surface array, through the bionic design of combining a differential series structure (for detecting a deflection force) with an integral parallel structure (for detecting an axial force), in-situ self-decoupling of the sensor to multidimensional force components is realized at a sensing layer. The bending strain gradient is decoupled through the series differential structure, common-mode noise interference is effectively inhibited, and axial strain is isolated, the parallel integral structure is combined to perform spatial summation on uniformly distributed axial strain, and multidimensional force decoupling in a physical structure and natural blocking of crosstalk between different dimensions of force are realized; the sensor is connected with the readout circuit in-situ, parasitic capacitance is reduced, signal transmission reliability is improved, the signal-to-noise ratio and the measurement accuracy are significantly improved, and the dependence on a complex backend conditioning circuit is reduced.

Description

Technical Field

[0001] This application relates to the field of sensor and measurement and control technology, and in particular to a flexible conformal piezoelectric multidimensional force sensor. Background Technology

[0002] Multidimensional force measurement is of great significance in high-end equipment and engineering applications such as intelligent manufacturing (including machining process monitoring, tool status recognition / force control, digital twins), precision force control and operation of robots, tactile feedback in minimally invasive surgery, precision manufacturing process monitoring, spacecraft force sensing, and structural health monitoring. However, most existing three-dimensional force sensors are based on rigid structures and employ principles such as resistance strain gauges, optical fibers, or microelectromechanical systems (MEMS). Although they can achieve multi-component force detection, they generally have the following shortcomings: First, they are large in size and have high rigidity, making it difficult to achieve conformal integration with complex curved surfaces or micro-components; second, the manufacturing and processing costs are high, which is not conducive to distributed, multi-point force measurement; and third, their application in scenarios such as flexible wearable devices and curved structure monitoring is limited.

[0003] In recent years, flexible piezoelectric polymer (such as polyvinylidene fluoride PVDF) films have become an important development direction in the field of mechanical measurement due to their lightweight, flexibility, ease of processing, and excellent force-to-electric conversion properties. However, most existing flexible piezoelectric sensors are used for uniaxial strain detection or multi-point measurement with few channels, and lack the ability to perform arrayed and decoupled three-dimensional force detection. When it is necessary to acquire multi-dimensional signals simultaneously, significant crosstalk effects often occur, leading to a decrease in measurement accuracy and stability, which cannot meet the requirements for high-resolution, high-precision three-dimensional force sensing in applications such as robotics, medical devices, and precision machining. Summary of the Invention

[0004] The purpose of this application is to provide a flexible conformal piezoelectric multidimensional force sensor that can realize the detection of multidimensional forces through arraying and mechanical decoupling.

[0005] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides a flexible conformal piezoelectric multidimensional force sensor, comprising: a piezoelectric thin film and an electrode array disposed on the piezoelectric thin film; the electrode array comprises six electrode elements, respectively referred to as the first electrode element to the sixth electrode element; each electrode element comprises an upper and lower electrode element pair; the upper electrode element and the lower electrode element are respectively disposed on two sides of the piezoelectric thin film and are positioned correspondingly. The piezoelectric film includes a first detection area and a first contact area and a second detection area disposed on both sides of the first detection area; the first detection area includes a first electrode surface element to a fourth electrode surface element; the second detection area includes a fifth electrode surface element and a sixth electrode surface element. When a piezoelectric film is coated on the surface of the object to be measured to measure multidimensional forces, the first to fourth electrode elements are arranged along the circumference of the object to be measured, and adjacent electrode elements are set at equal intervals; the fifth and sixth electrode elements are arranged symmetrically with the second and third electrode elements along the same axis of symmetry. The first and third electrode elements, the second and fourth electrode elements are connected in series differentially; the fifth and sixth electrode elements are connected in parallel integrally. The upper electrode elements of the first to fourth electrode elements, the lower electrode element of the fifth electrode element, and the upper electrode element of the sixth electrode element are respectively connected to the six contacts of the first contact area.

[0006] Secondly, this application provides a flexible conformal piezoelectric multidimensional force sensor, including: a piezoelectric thin film and an electrode array disposed on the piezoelectric thin film; the electrode array includes six electrode elements, respectively referred to as the first electrode element to the sixth electrode element; each electrode element includes an upper and lower electrode element pair; the upper electrode element and the lower electrode element are respectively disposed on two sides of the piezoelectric thin film and are in corresponding positions. The piezoelectric film includes a first detection area and a second contact area and a second detection area disposed on both sides of the first detection area; the first detection area includes a first electrode surface element to a fourth electrode surface element; the second detection area includes a fifth electrode surface element and a sixth electrode surface element; When a piezoelectric film is coated on the surface of the object to be measured to measure multidimensional forces, the first to fourth electrode elements are arranged along the circumference of the object to be measured, and adjacent electrode elements are set at equal intervals; the fifth and sixth electrode elements are arranged symmetrically with the second and third electrode elements along the same axis of symmetry. The fifth and sixth electrode elements adopt a parallel integral connection structure; The upper and lower electrode elements of the first to fourth electrode elements, the lower electrode element of the fifth electrode element, and the upper electrode element of the sixth electrode element are respectively connected to the ten contacts of the second contact area.

[0007] Thirdly, this application provides a flexible conformal piezoelectric multidimensional force sensor, comprising: a piezoelectric thin film and an electrode array disposed on both sides of the piezoelectric thin film; the electrode array comprises N+1 electrode element groups; the piezoelectric thin film comprises a first detection area and a third contact area and a third detection area disposed on both sides of the first detection area; the first detection area comprises one electrode element group; the third detection area comprises N of the electrode element groups; N≥1; Each electrode element group includes a first electrode element to a fourth electrode element; each electrode element includes an upper and lower electrode element pair; the upper electrode element and the lower electrode element are respectively disposed on two sides of the piezoelectric film and are in corresponding positions; when the piezoelectric film is covered on the surface of the object to be measured to measure multidimensional force, the first electrode element to the fourth electrode element are arranged along the circumference of the object to be measured, and adjacent electrode elements are equally spaced. For each electrode element group, the first electrode element and the third electrode element, and the second electrode element and the fourth electrode element adopt a series differential connection structure; Each upper electrode element in the first and third detection areas is connected to M contacts in the third contact area; M=4 (N+1).

[0008] Fourthly, this application provides a readout circuit for the flexible conformal piezoelectric multidimensional force sensor described in the first aspect, comprising: three first readout sub-circuits; each first readout sub-circuit has the same structure; Each first readout sub-circuit includes: a conditioning capacitor, a junction field-effect transistor, a gate resistor, a source resistor, and a drain resistor; The conditioning capacitor and the gate resistor are connected in parallel; one end of the gate resistor is connected to the gate of the junction field-effect transistor (JFET), and the other end of the gate resistor is grounded. The drain of the JFET is connected to the power interface through the drain resistor, and the source of the JFET is grounded through the source resistor. The source of the JFET is also connected to the signal output interface. The two ends of the conditioning capacitor of the first readout sub-circuit are respectively connected to the contacts connected to the upper electrode surface of the third electrode element and the first electrode surface element. The two ends of the conditioning capacitor of the second first readout sub-circuit are respectively connected to the contacts connected to the upper electrode surface of the fourth electrode element and the second electrode element. The two ends of the conditioning capacitor of the third first readout sub-circuit are respectively connected to the contacts connected to the lower electrode surface of the fifth electrode surface and the upper electrode surface of the sixth electrode surface.

[0009] Fifthly, this application provides a readout circuit for the flexible conformal piezoelectric multidimensional force sensor described in the first aspect, comprising: three second readout sub-circuits; each second readout sub-circuit has the same structure; Each readout sub-circuit includes a first circuit group and a second circuit group; the first circuit group and the second circuit group have the same structure. Each first circuit group includes: a conditioning capacitor, a junction field-effect transistor, a gate resistor, a source resistor, and a drain resistor; The conditioning capacitor and the gate resistor are connected in parallel; one end of the gate resistor is connected to the gate of the junction field-effect transistor (JFET), and the other end of the gate resistor is grounded. The drain of the JFET is connected to the power interface through the drain resistor, and the source of the JFET is grounded through the source resistor. The source of the JFET is also connected to the signal output interface. The gates of the junction field-effect transistors in the first and second circuit groups of the first and second readout sub-circuit are also connected to the contacts connected to the upper electrode elements of the first and third electrode elements, respectively. The gates of the junction field-effect transistors in the first and second circuit groups of the second second readout sub-circuit are also connected to the contacts connected to the upper electrode elements of the second and fourth electrode elements, respectively. The gates of the junction field-effect transistors in the first and second circuit groups of the third second readout sub-circuit are also connected to the contacts connected to the lower electrode element of the fifth electrode element and the upper electrode element of the sixth electrode element, respectively.

[0010] In a sixth aspect, this application provides a readout circuit for the flexible conformal piezoelectric multidimensional force sensor described in the second aspect, comprising: five first readout sub-circuits; each first readout sub-circuit has the same structure; Each first readout sub-circuit includes: a conditioning capacitor, a junction field-effect transistor, a gate resistor, a source resistor, and a drain resistor; The conditioning capacitor and the gate resistor are connected in parallel; one end of the gate resistor is connected to the gate of the junction field-effect transistor (JFET), and the other end of the gate resistor is grounded. The drain of the JFET is connected to the power interface through the drain resistor, and the source of the JFET is grounded through the source resistor. The source of the JFET is also connected to the signal output interface. The two ends of the conditioning capacitor of the first readout sub-circuit are respectively connected to the contacts connected to the upper electrode element and the lower electrode element of the first electrode element. The two ends of the conditioning capacitor of the second first readout sub-circuit are respectively connected to the contacts connected to the upper electrode element and the lower electrode element of the second electrode element. The two ends of the conditioning capacitor of the third first readout sub-circuit are respectively connected to the contacts connected to the upper electrode element and the lower electrode element of the third electrode element. The two ends of the conditioning capacitor of the fourth first readout sub-circuit are respectively connected to the contacts connected to the upper electrode element and the lower electrode element of the fourth electrode element. The two ends of the conditioning capacitor of the fifth first readout sub-circuit are respectively connected to the contacts connected to the upper and lower electrode elements of the fifth electrode element.

[0011] In a seventh aspect, this application provides a readout circuit for the flexible conformal piezoelectric multidimensional force sensor described in the third aspect, comprising: 2 (N+1) first readout sub-circuits; each first readout sub-circuit has the same structure; Each first readout sub-circuit includes: a conditioning capacitor, a junction field-effect transistor, a gate resistor, a source resistor, and a drain resistor; The conditioning capacitor and the gate resistor are connected in parallel; one end of the gate resistor is connected to the gate of the junction field-effect transistor (JFET), and the other end of the gate resistor is grounded. The drain of the JFET is connected to the power interface through the drain resistor, and the source of the JFET is grounded through the source resistor. The source of the JFET is also connected to the signal output interface. In the flexible conformal piezoelectric multidimensional force sensor described in the third aspect, each electrode surface element corresponds to two first readout sub-circuits; For each electrode element group, the two ends of the conditioning capacitor of the first readout sub-circuit are respectively connected to the contacts of the third electrode element and the upper electrode element of the first electrode element in the corresponding electrode element group. The two ends of the conditioning capacitor of the second first readout sub-circuit are respectively connected to the contacts of the fourth electrode element and the upper electrode element of the second electrode element in the corresponding electrode element group.

[0012] Eighthly, this application provides a flexible conformal piezoelectric multidimensional force sensor, comprising: the flexible conformal piezoelectric multidimensional force sensor described in the first aspect and the readout circuit described in the fourth aspect, or the flexible conformal piezoelectric multidimensional force sensor described in the first aspect and the readout circuit described in the fifth aspect, or the flexible conformal piezoelectric multidimensional force sensor described in the second aspect and the readout circuit described in the sixth aspect, or the flexible conformal piezoelectric multidimensional force sensor described in the third aspect and the readout circuit described in the seventh aspect; the signal output terminal of the flexible conformal piezoelectric multidimensional force sensor and the signal input terminal of the corresponding readout circuit are connected in near-in-situ.

[0013] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides a flexible conformal piezoelectric multidimensional force sensor, which includes a sensor and a readout circuit connected to the sensor in near-in-situ. The sensor is designed based on the sensing structure and mechanism of mammalian protective hair follicle receptors and includes a piezoelectric thin film and an electrode array disposed on the piezoelectric thin film. The electrode array employs both series differentially connected electrode element structures and parallel integrally connected electrode element structures. Through a biomimetic design combining a differential series structure (for detecting deflection forces Fx / Fy) and an integral parallel structure (for detecting axial force Fz), the sensor achieves mechanical in-situ decoupling of multidimensional force components at the multidimensional force sensing level. By extracting the bending strain gradient through differential operations, common-mode noise interference is effectively suppressed and axial strain is isolated. The parallel integral structure spatially sums the uniformly distributed axial strain, achieving multidimensional force decoupling in physical structure and naturally blocking crosstalk between forces of different dimensions. This improves the signal-to-noise ratio and measurement accuracy, and reduces dependence on complex back-end conditioning circuits. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the structure of the first flexible conformal piezoelectric multidimensional force sensor provided in the embodiments of this application; Figure 2 A schematic diagram of the functional end structure of various types of test rods applicable to the embodiments of this application; Figure 3 A schematic diagram illustrating the three-dimensional force decoupling principle of integrating a sensor with the target being measured (taking an end mill as an example) as provided in the embodiments of this application; Figure 4 Interface layout and electrode routing design diagram of the area array provided in the embodiments of this application; Figure 5 A schematic diagram of a customized design for an electrode surface element provided in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of the second type of flexible conformal piezoelectric multidimensional force sensor provided in Embodiment 2 of this application; Figure 7 This is a schematic diagram of the structure of the third type of flexible conformal piezoelectric multidimensional force sensor provided in Embodiment 3 of this application; Figure 8 This is a schematic diagram of the readout circuit of the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 1, provided in Embodiment 4 of this application; Figure 9 This is a diagram showing the overall flexible bending effect of the flexible sensor array and near-in-situ readout circuit after coupling and integration in Embodiment 4 of this application. Figure 10 This is a schematic diagram of another readout circuit of the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 1, provided in Embodiment 5 of this application; Figure 11 This is a schematic diagram of the readout circuit of the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 2, which is provided for Embodiment 6 of this application.

[0016] Figure label: 1: The rod under test; 2: Sensing array; 2-1: Upper electrode array; A1: First upper electrode element; B1: Second upper electrode element; A2: Third upper electrode element; B2: Fourth upper electrode element; C1: Fifth upper electrode element; C2: Sixth upper electrode element; 2-2: Piezoelectric film; 2-3: Lower electrode array; A1': First lower electrode element; B1': Second lower electrode element; A2': Third lower electrode element; B2 ': Fourth lower electrode element; C1': Fifth lower electrode element; C2': Sixth lower electrode element; 3: Readout circuit; 3-1: Signal output interface area; 3-2: Conditioning circuit area; 3-2-1: Circuit ground layer; 3-2-2: Power supply input terminal; 3-2-3: Grounding input terminal; 3-3: Signal input interface area; 3-3-1: Interface leakage protection area; 3-3-2: Interface electrode through hole; 3-4: Sensor array area. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] Besides the fact that most existing flexible piezoelectric sensors are used for uniaxial strain detection or multi-point measurement with few channels, lacking the ability for three-dimensional force detection through arraying and decoupling, flexible piezoelectric arrays, from a readout mechanism perspective, are characterized by high output impedance and low charge, making them highly susceptible to external interference and signal attenuation. This places high demands on the readout circuitry for high input impedance, low noise, and strict parasitic parameter management. As the array size and channel density increase, crosstalk / mutual coupling between channels intensifies significantly, limiting signal integrity. Under the constraints of surface-mount (near-in-situ) integration and compact packaging, balancing return path design, shielding measures, and space constraints becomes a key challenge for robustness and stability. In terms of applications, flexible arrays often need to simultaneously acquire dynamic high-speed signals and quasi-static slowly varying signals; however, traditional readout architectures have fixed channel configurations, making it difficult to balance bandwidth, sensitivity, and hold-up capability, thus limiting wideband and multi-mode measurement performance. In system integration, the anti-interference capability of multi-channel readout circuits is highly dependent on the effectiveness of shielding / grounding strategies. Existing technologies struggle to coordinate the management of shielded ground and signal ground networks and port layouts within limited spaces, resulting in insufficient noise coupling and common-mode rejection.

[0019] Therefore, there is an urgent need for a system-level flexible conformal three-dimensional force sensor array solution: while maintaining the advantages of flexibility and conformality, it uses a biomimetic-inspired differential / integral array structure design and optimized electrode geometry layout, combined with high input impedance multi-channel near-in-situ readout, to construct an array interconnection-readout port mapping model, and provides a channel-level independent configurable conditioning mechanism (flexibly setting gain, bandwidth, time constant and signal holding characteristics), combined with multi-layer common ground shielding and port collaborative management to suppress parasitic effects and inter-channel coupling, thereby realizing array-based, low-noise, high-precision decoupled measurement of three-dimensional force components (Fx, Fy, Fz), meeting the miniaturization, distributed and high consistency requirements of typical scenarios such as precision machining tool force monitoring, robot joint force control, precision assembly force measurement and medical device mechanical testing.

[0020] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] Example 1 This embodiment provides a flexible conformal piezoelectric multidimensional force sensor, which adopts a flexible conformal piezoelectric three-dimensional force sensing array (hereinafter referred to as sensing array 2). During multidimensional force measurement, the sensing array 2 is attached to the surface of the object being measured (i.e., the rod to be measured 1), and its installation does not change the original structural stiffness and mechanical properties. For example... Figure 1 As shown, Figure 1 A schematic diagram and an array structure diagram of a flexible conformal piezoelectric three-dimensional force sensor conformally integrated on a rod are shown.

[0022] The sensing array 2 employs a flexible piezoelectric thin film 2-2 and patterned electrodes, integrating biomimetic mechanical design: the deflection force sensing array adopts a differential series topology, which extracts the bending strain gradient to achieve in-situ mechanical decoupling of (Fx, Fy) and suppress common-mode interference; the axial force sensing array adopts an integral parallel topology, which achieves high sensitivity to Fz and crosstalk isolation by spatial summation of uniform axial strain. The design of the deflection force and axial force sensing array structures is inspired by the division of labor mechanism of Aβ rapid adaptive low-threshold mechanoreception (Aβ RA-LTMR) and Aβ field-low-threshold mechanoreception (Aβ field-LTMR) in mammalian guard hair follicles, respectively, to achieve front-end decoupling of deflection force / axial force in the mechanical domain and effectively isolate crosstalk.

[0023] Among them, the rod to be tested 1 is an axially extending slender structure. The area where the sensing array 2 is installed should have a cross-section with rotational symmetry or regular geometric shape, including but not limited to circular, square, and polygonal configurations, such as round rods, square rods, prisms, cylinders, and various machining tools with cutting tips or teeth at the ends (such as milling cutters, turning tools, boring tools, etc., the morphology of the functional end of milling cutters is shown in the figure). Figure 2 (a) The functional end structure of the rod under test 1 is not restricted and can be a mechanical connection structure (e.g., Figure 2 (d) in the middle), ball-head force measuring components (such as Figure 2 (b) of the above), medical devices (such as endoscopes, Figure 2 (c) or other functional components. The "functional end" refers to the critical part of the rod 1 under test used to perform a specific operation or measurement (this part is not specified in the original text). Figure 1 As shown, see Figure 3 (The middle milling cutter teeth are an example of the functional end of machining).

[0024] The attachment methods for the sensing array 2 include, but are not limited to, using adhesives (such as AB glue, epoxy resin glue, 502 instant glue, etc.) or special tapes (such as high-temperature tape, double-sided tape, metal foil tape, etc.) for fixation. The attachment method must ensure the effective transfer of strain / stress from the measured rod 1 to the sensing array 2, avoiding excessive attenuation. Users can select the attachment material according to measurement requirements. High-modulus adhesives (such as AB glue) are suitable for high-efficiency strain transfer applications; low-modulus materials (such as certain double-sided tapes) can be used in scenarios with specific requirements for strain attenuation.

[0025] The sensing array 2 includes a piezoelectric thin film 2-2 and an electrode array disposed on the piezoelectric thin film 2-2, specifically an upper electrode array 2-1 and a lower electrode array 2-3 disposed on both sides of the piezoelectric thin film. To ensure the detection performance of the flexible conformal piezoelectric multidimensional force sensor, an insulating layer is disposed on the outside of the upper electrode array 2-1 and the lower electrode array 2-3, and a shielding layer is disposed on the outside of the insulating layer. The terms "upper" and "lower" in "upper electrode array 2-1" and "lower electrode array 2-3" are only used to distinguish the arrays disposed on both sides of the piezoelectric thin film, and do not define their vertical orientation.

[0026] Among them, such as Figure 1 As shown, the upper electrode array 2-1, the piezoelectric thin film 2-2, and the lower electrode array 2-3 are stacked. The upper and lower electrode arrays 2-3 are formed on both sides of the piezoelectric thin film 2-2 through an alignment process. They can be prepared in one step using high-precision metal coating or patterned screen printing technology to ensure the size and positional accuracy of the elements.

[0027] The piezoelectric thin film 2-2 can be any piezoelectric polymer material that meets the requirements, preferably one with significant in-plane polarization and large anisotropy of the piezoelectric coefficient (e.g., d31>d32). The sensing direction of the sensing array 2 should be consistent with the direction of the most significant in-plane polarization of the thin film. Taking a typical PVDF thin film as an example, its d31 coefficient is significantly greater than d32, so the sensing direction of the array elements is usually arranged along the stretching direction of the thin film, such as... Figure 1 As shown.

[0028] The piezoelectric film 2-2 includes a first detection area and a first contact area and a second detection area located on both sides of the first detection area; the electrode array on the piezoelectric film includes six electrode elements, which are respectively denoted as the first electrode element to the sixth electrode element; each electrode element includes an upper and lower electrode element pair; the upper electrode element and the lower electrode element are respectively located on both sides of the piezoelectric film and their positions correspond.

[0029] like Figure 1 As shown, the first detection area corresponding to the upper electrode array 2-1 includes the first upper electrode element A1 to the fourth upper electrode element B2; the second detection area corresponding to the upper electrode array 2-1 includes the fifth upper electrode element C1 and the sixth upper electrode element C2. The lower electrode array 2-3 includes the first lower electrode element A1' to the sixth lower electrode element C2'; the positions of the first lower electrode element A1' to the sixth lower electrode element C2' correspond one-to-one with the positions of the first upper electrode element A1 to the sixth upper electrode element C2.

[0030] When the piezoelectric film 2-2 is applied to the surface of the rod 1 under test to measure multidimensional forces, the first upper electrode element A1 to the fourth upper electrode element B2 are arranged circumferentially along the rod under test, with equal intervals between adjacent upper electrode elements. As an example, the electrode elements can be arranged symmetrically at four azimuth angles: 0°, 90°, 180°, and 270°. Figure 1 As shown, the azimuth angle can be customized. Typically, 0° is set as the positive X-axis direction, 180° as the negative X-axis direction, 90° as the positive Y-axis direction, and 270° as the negative Y-axis direction. The Z-axis is perpendicular to the XY plane and along the axis of the member. All angle and direction definitions must conform to the rules of the Cartesian coordinate system.

[0031] The fifth upper electrode element C1 and the sixth upper electrode element C2 are arranged symmetrically with the second upper electrode element B1 and the third upper electrode element A2 along the same axis of symmetry. For example... Figure 1 As shown, as an example, the fifth upper electrode element C1 and the fifth lower electrode element C1' are arranged in the range of 0° to 90°, and the sixth upper electrode element C2 and the sixth lower electrode element C2' are arranged in the range of 180° to 270°.

[0032] The upper and lower electrode arrays consist of multiple facet elements, conformally covering the surface of the rod under test 1. Figure 1For example, the element pairs A1 / A1', B1 / B1', A2 / A2', and B2 / B2' are located at 0°, 90°, 180°, and 270° azimuths, respectively. Element pairs A1 / A1' and A2 / A2' are centrally symmetrical (180° apart), and B1 / B1' and B2 / B2' are also centrally symmetrical. Element pairs C1 / C1' and C2 / C2' each consist of four smaller elements, symmetrically distributed. Electrode elements A (A1 / A1' and A2 / A2'), B (B1 / B1' and B2 / B2'), and C (C1 / C1' and C2 / C2') are used to detect forces in the X, Y, and Z directions, respectively. The orientation of the electrode elements can be customized by the user; the actual three-dimensional force direction is determined through decoupling calculations, using the element orientation as a reference. The rod segments in the sensor placement area should preferably be rotationally symmetric (e.g., circular or square cross-sections) to allow for symmetrical arrangement of sensing elements at four angles: 0°, 90°, 180°, and 270°. The shape and function of the remaining parts of the rods are not limited and can be designed according to actual needs.

[0033] All electrode elements are designed on the same piezoelectric film 2-2, and their orientation on the test rod 1 is achieved by calculating the spacing between the electrode elements. Taking a round rod as an example, when measuring force by attaching the electrode elements to the surface of the round rod, the arc length spacing between the centers of adjacent electrode elements can be expressed as f=π(D+2k) / 4, where D is the rod diameter and k is the additional thickness caused by the adhesive material (such as adhesive layer or tape). The corresponding spacing for a square rod is f=a+k, where a is the side length. For rectangular cross-section rods, electrode elements are usually arranged at the center of each face.

[0034] The first electrode element and the third electrode element adopt a series differential connection structure, such as Figure 1 As shown, the first lower electrode element A1' is connected to the third lower electrode element A2', and the first upper electrode element A1 and the third upper electrode element A2 are connected to the corresponding contacts in the first contact area; the second electrode element and the fourth electrode element adopt a series differential connection structure, as shown in the figure. Figure 1 As shown, the second lower electrode element B1' is connected to the fourth lower electrode element B2', and the second upper electrode element B1 is connected to the corresponding contacts of the first contact area; the fifth and sixth electrode elements adopt a parallel integral connection structure, as shown in the figure. Figure 1 As shown, the fifth upper electrode element C1 is connected to the sixth upper electrode element C2, and the fifth lower electrode element C1' is connected to the sixth lower electrode element C2'. The sixth upper electrode element C2 and the fifth lower electrode element C1' are connected to the corresponding contacts in the first contact area. The first upper electrode elements A1 to B2, the fifth lower electrode element C1', and the sixth upper electrode element C2 are respectively connected to the six contacts in the first contact area, as shown. Figure 1 As shown.

[0035] The three-dimensional forces (Fx, Fy, Fz) are defined with reference to the rod 1 under test, including the deflection force (Fx, Fy) perpendicular to the rod's axis and the axial force (Fz) parallel to the axis. The origin of the coordinate system is located on the axis of the rod 1 under test. Figure 3 As shown, the Fx sensing elements (first and third electrode elements) and the Fy sensing elements (second and fourth electrode elements) employ a series differential structure to sense the deflection force, as follows: Figure 3 In (d) and (e), the Fz sensing elements (the fifth and sixth electrode elements) employ a parallel integral structure to sense axial force, such as... Figure 3 (f) In this design, the upper electrode elements A1, B1, and C1 / C2 serve as signal readout elements, each connected individually to the input of the readout circuit 3. The upper electrode elements A2 and B2, along with the lower electrode elements C1' / C2', are grounded and share a common ground with the rod under test 1 and the readout circuit 3. This design utilizes the series-parallel connection of element structures rather than the series-parallel connection of circuits for multidimensional force measurement, simplifying the number of interfaces and leads.

[0036] The electrode routing of sensing array 2 (routing between electrode elements and routing of electrode element lead-out contacts) follows the principles of compactness and standardization, and must avoid short circuits and minimize parasitic capacitance, such as... Figure 4 As shown, Figure 4 The diagram shows the interface layout and electrode routing design of the array, including on-plane and off-plane routing strategies and interface location design. Figure 4 In the diagram, (b) shows the same-side electrode traces, (c) shows the opposite-side electrode traces, and (d) shows the opposite-side electrode cross traces. The electrode traces on both sides of the piezoelectric thin film 2-2 require coordinated design: traces on the same layer should be compact to reduce device size and parasitic capacitance, while avoiding excessive proximity (e.g., ...). Figure 4 (b) in the above text causes a short circuit; overlapping of traces on different layers should be avoided as much as possible (e.g., Figure 4 (c) and (d) in the diagram are used to reduce parasitic capacitance caused by cross-coupling. All traces use smooth transitions to reduce stress concentration, which is beneficial for flexible packaging.

[0037] The interface of the sensing array 2 (e.g.) Figure 4 The interface between the first contact area (a) and the readout circuit 3 adopts a standardized design, with consistent contact spacing across all channels and leads from the same side (first contact area). The interface position can be horizontally offset to accommodate different rod shapes: a centered arrangement is suitable for round rods, such as... Figure 4 (e) in the diagram represents the interface of the central array. Offset arrangement can avoid the edges of the square rods, such as... Figure 4 In the diagram, (f) represents the horizontally offset array interface.

[0038] Electrode element design must balance performance uniformity, sensitivity, and accuracy. The electrode elements on both sides of the piezoelectric film 2-2 must be precisely aligned to ensure consistent capacitance. The element size should be optimized based on the rod size: too large an element can lead to strain field averaging effects, reducing spatial resolution; too small an element will reduce sensitivity. The voltage response sensitivity Rv of the element to force (strain / stress) can be approximated as: (1) in, For output voltage changes, This represents the strain change along the tensile direction of the thin film. For the Young's modulus of the thin film, , The piezoelectric coefficient of the thin film. For the Poisson's ratio of the thin film, For film thickness, , These are the vacuum permittivity and the relative permittivity of the thin film, respectively. To improve sensitivity, thicker and higher thicknesses can be selected. ,Low ,Low The piezoelectric film 2-2, however, requires the film thickness to be selected appropriately based on the geometry of the rod, while also considering the film's flexibility. Once the relevant parameters of the piezoelectric film are determined, the voltage response sensitivity Rv of the elements on the piezoelectric film to force (strain / stress) is then determined.

[0039] The theoretical voltage response sensitivity Rv can be calculated using equation (1). However, in practical systems, structures such as electrode cross-tracing in the array and readout circuit 3 will inevitably introduce parasitic capacitance, thereby weakening the actual output piezoelectric response signal. Therefore, the parasitic capacitance of the array should be considered in practical applications. Parasitic capacitance of readout circuit 3 Afterwards, the actual output voltage is: (2) in, It is a surface capacitor; , To improve the effective alignment area of ​​the electrodes Increasing the area S can reduce the effect of parasitic capacitance, but if S is too large, it will cover too much of the circumferential area and reduce the resolution.

[0040] To ensure the uniformity of electrode surface element performance, a customized electrode design is adopted, such as... Figure 5 As shown, using a single electrode element in the upper electrode array 2-1 (such as the fifth upper electrode element C1) as a reference, its area S is precisely controlled; the area of ​​the corresponding element in the lower electrode array 2-3 (such as the fifth lower electrode element C1') is slightly enlarged to compensate for alignment errors. This design is applicable to both deflection force and axial force arrays. Figure 5Methods for compensating the front and back electrode dimensions to improve capacitance consistency and alignment accuracy are demonstrated.

[0041] For the axial force array (the fifth and sixth electrode elements), after determining the design of one of the surface elements, for example, the individual surface elements of the upper electrode array 2-1 (such as...) Figure 5 The area S of a single surface element of C1 in (a) is designed to be an accurate value. Alternatively, all surface elements of the lower electrode array 2-3 can be enlarged and designed as a single integral surface element (such as...). Figure 5 In (b) C1'), the alignment error is minimized, thanks to its parallel integral structure.

[0042] To further improve axial force sensitivity, the four sub-surfaces of each of surface element C1, surface element C1', surface element C2, and surface element C2' can be merged into a large area surface element (e.g., Figure 5 (c) C1 and C1'), and can be extended axially to increase capacitance (e.g. Figure 5 (C1 and C1' in (d)). After merging, the elements still maintain a 180° symmetrical arrangement. At this time, a reference element design is still required (such as using...). Figure 5 (C1 in (c) and (d) is the reference) and the enlarged reverse electrode ( Figure 5 The method of C1' in (c) and (d) controls the capacitor accuracy.

[0043] Based on the above, as an optional implementation, the fifth upper electrode element C1, the fifth lower electrode element C1', the sixth upper electrode element C2, and the sixth lower electrode element C2' each include multiple element blocks; the multiple element blocks are spaced apart and adjacent element blocks are connected on one side. As another optional implementation, the fifth upper electrode element C1, the fifth lower electrode element C1', the sixth upper electrode element C2, and the sixth lower electrode element C2' each use a single integral element. As yet another optional implementation, the fifth upper electrode element C1 and the sixth upper electrode element C2 each include multiple element blocks; the multiple element blocks are spaced apart and adjacent element blocks are connected on one side; the fifth lower electrode element C1' and the sixth lower electrode element C2' each use a single integral element.

[0044] As an optional implementation, the area of ​​each electrode element in the reverse electrode array is greater than or equal to the area of ​​each electrode element in the corresponding front electrode array; when the reverse electrode array is the upper electrode array 2-1, the front electrode array is the lower electrode array 2-3; when the reverse electrode array is the lower electrode array 2-3, the front electrode array is the upper electrode array 2-1.

[0045] based on Figure 1 The sensor structure shown illustrates the decoupling method for three-dimensional forces (Fx, Fy, Fz) using an end mill as an example (e.g., Figure 3The sensing array 2 is conformally attached to the tool holder, establishing a coordinate system with the end mill as the reference: the Z-axis is along the tool axis (from the tip to the tool holder is positive), and the X and Y axes are located within the cross-section and perpendicular to the axis (positive directions are as follows). Figure 3 As shown in (a)). Surface pairs A1 / A1', B1 / B1', A2 / A2', and B2 / B2' are arranged at 0°, 90°, 180°, and 270° orientations, respectively (e.g., ...). Figure 3 As shown in (b) of the diagram, the force Fx and Fy are converted from the forces Fcx and Fcy applied to the blade tip. Surface element pairs C1 / C1' and C2 / C2' are arranged in the ranges of 0°~90° and 180°~270° respectively, jointly responding to the force Fz converted from force Fcz. The surface element arrangement orientation is shown in [reference]. Figure 3 (c) in the middle. Figure 3 (a) shows the three-dimensional force decoupling principle of the end mill; (b) shows the magnified structure of the integrated surface array; (c) shows the orientation and structure of the surface array; (d) shows the response principle of the surface array sensing the Fx force component; (e) shows the response principle of the surface array sensing the Fy force component; and (f) shows the response principle of the surface array sensing the Fz force component.

[0046] The three-dimensional force decoupling method is based on a rod mechanics model. The force on the tool tip is transmitted to the position of the sensing array (e.g., ...) through the rod in the form of strain. Figure 3 As shown in (a)). The force-strain relationship is as follows (taking round rods, rectangular rods, and square rods as examples, but not limited to these): Maximum bending strain caused by deflection forces Fx and Fy: Round rod: Rectangular rod: Square bar: (3) Axial force Fz causes tensile and compressive strain: Round rod: Rectangular rod: Square bar: (4) Under the same force F, the ratio of bending strain to axial strain is: Round rod: Rectangular rod: Square bar: (Square bar) (5) Where F is the force applied to the rod 1 under test. Let E be the distance from the point of application of force to the center of the surface element, E be the Young's modulus of the rod, d be the diameter of the round rod, b and h be the width and height of the rectangular rod section, and m be the side length of the square rod.

[0047] After the force on the rod is converted into strain, it is sensed by the surface array. In practice, the strain transmission attenuation caused by adhesive layers, etc., must be considered, which can be compensated for through calibration. Usually, the rod length is much larger than the cross-sectional size, so the bending strain is significantly greater than the axial strain. Therefore, the size of the deflection force surface element can be smaller, while the area of ​​the axial force surface element needs to be increased to improve sensitivity. The axial force strain distribution is uniform, so its surface element size design is mainly driven by sensitivity and has no strict orientation restrictions.

[0048] Taking a circular rod as an example, the bending strain distribution can be further expressed as: (6) Where n is the distance of the surface element from the neutral axis. The strain is unevenly distributed circumferentially, and the average strain sensed by the surface element... Affected by its size: (7) in, a Let be the side length of the surface element. Based on this corrected average strain and considering transmission attenuation, the actual sensitivity of the surface element can be calculated according to formula (1). .

[0049] Based on the above decoupling model, the specific three-dimensional force decoupling process is as follows: When the tool tip is subjected to a force Fcx in the X direction, the rod undergoes bending deformation. According to the bending strain distribution law (see formula (6)), the strain reaches its extreme value in the X direction (i.e., the direction of bending under force) due to the maximum distance n from the neutral axis. In the Y direction perpendicular to it, the strain is approximately zero due to the distance n from the neutral axis approaching zero. This strain distribution characteristic provides a mechanical basis for decoupling the Fx and Fy components. Furthermore, since the absolute values ​​of the bending strain are equal but opposite in the positive and negative X directions, the surface elements A1 / A1′ and A2 / A2′ symmetrically arranged at the 0° and 180° positions of the rod can respectively sense strain signals with equal amplitude and opposite polarity. This signal is transmitted through a series differential structure ( Figure 3 The output voltage of the surface elements A1 / A1′ and A2 / A2′ in (d) is effectively multiplied (the two surface elements are equivalent to two voltage sources in series, and the theoretical value is twice that of a single surface element output); at the same time, the common-mode noise caused by environmental temperature changes or electromagnetic interference has a consistent spatial distribution, and it appears as an interference signal with equal magnitude and phase in the two surface elements. This differential series structure can directly cancel such common-mode noise; finally, this differential configuration can selectively extract the strain gradient component related to Fx, while effectively suppressing the coupling interference caused by Fy (strain is almost zero in the Y direction) and Fz (strain is uniformly distributed everywhere due to Fz, and is canceled after differential), thereby significantly improving the sensing accuracy, signal-to-noise ratio and anti-interference ability of the force in the X direction.

[0050] Similarly, when the tool tip is subjected to a force Fcy in the Y direction, the surface element pairs B1 / B1' and B2 / B2' operate in a differential mode (e.g., Figure 3 In (e), its output signal also achieves multiplication and common-mode noise suppression, thereby decoupling the Fy component and effectively isolating the interference of Fx and Fz.

[0051] For the axial force Fcz, it induces a uniformly distributed strain field in the circumferential direction of the rod. Therefore, each surface element of the differentially connected X and Y direction senses the axial strain of the same magnitude and polarity, and generates the same piezoelectric response signal; these signals cancel each other out due to opposite polarities in the series differential structure, resulting in no net signal output, thus effectively suppressing the crosstalk of Fz to the deflection force measurement channel. The specially designed Z direction surface elements (C1 / C1' and C2 / C2') adopt a parallel integration structure (such as... Figure 3 In (f), each surface element is electrically connected in parallel, independently sensing the same axial strain. The piezoelectric response signals generated are directly accumulated and output, achieving an integral effect on strain. This design not only significantly enhances the signal output in the Fz direction but also effectively suppresses gradient strain interference caused by deflection forces Fx and Fy (which approaches zero after accumulation in the parallel surface elements), thus achieving effective decoupling and independent high-sensitivity sensing of the axial force Fz at the sensor structure level.

[0052] It can be seen that the decoupling of Fz and Fx / Fy is achieved through the array structure (parallel and series), while the decoupling of Fx and Fy relies on the difference in strain distribution caused by them in different orientations, which is collected by the corresponding array elements.

[0053] The three-dimensional force (Fx, Fy, Fz) output channels are independently decoupled, and their signal response characteristics are as follows: X-axis force only (0° or 180°): Fx channel outputs positive or negative voltage, Fy and Fz have no output.

[0054] Y-axis force only (90° or 270°): Fy channel outputs positive or negative voltage, Fx and Fz have no output.

[0055] X and Y forces in the same direction (45° or 225°): Fx and Fy channels output voltages in phase and with equal amplitude, while Fz has no output.

[0056] X and Y opposite forces (135° or 315°): Fx and Fy channels output opposite phase equal amplitude voltages, Fz has no output.

[0057] Z-axis force only (tension or compression): Fz channel outputs positive or negative voltage, Fx and Fy have no output.

[0058] By combining the resultant force F with the response characteristics of the surface element and the force-strain mapping analysis, the magnitude and direction of the resultant force can be calculated based on the phase and amplitude of the Fx and Fy channel signals. The polarity (positive or negative sign) of the surface array's response to strain is related to the film's attachment direction (front side facing outwards or back side facing outwards), and the above characteristics represent only one of these cases.

[0059] This embodiment has the following technical effects: (1) An in-situ self-decoupling structure and anti-interference mechanism based on biomimetic mechanics principles are proposed. By simulating the gradient sensing and integrated sensing mechanisms in biological systems, a biomimetic design combining a differential series structure (for detecting deflection forces Fx / Fy) and an integral parallel structure (for detecting axial force Fz) is adopted to achieve mechanical in-situ decoupling of three-dimensional force components at the sensor sensing level. This structure extracts the bending strain gradient through differential operations, effectively suppressing common-mode noise interference; by performing spatial summation of the uniformly distributed axial strain through parallel integration, crosstalk between forces of different dimensions is naturally blocked in the physical structure, significantly improving the signal-to-noise ratio and measurement accuracy, and reducing the dependence on complex back-end conditioning circuits.

[0060] (2) An application-oriented customized design system and a complete theoretical model were constructed. A complete analytical model of "force-strain-piezoelectric response" was proposed, providing a precise design and decoupling theoretical basis for rods with different cross-sectional shapes (such as round rods, square rods, and rectangular rods). This system supports highly flexible design and can optimize parameters such as element size, layout orientation, interface position (such as center or offset to avoid edges) and sensitivity-resolution according to actual application requirements. It is widely applicable to high-precision force measurement occasions such as precision machining, robotics, medical devices, and aerospace.

[0061] (3) This application can use high-precision metal coating or screen printing technology to form electrodes in one step, which ensures the accuracy of the surface element size and position and the consistency of the multi-faceted unit performance. The interface adopts a standardized and biasable design, which is not only easy to connect with the readout circuit 3, but also can adapt to components with different geometries, providing a reliable manufacturing basis for high spatial resolution distributed force measurement.

[0062] Example 2 This embodiment provides a flexible conformal piezoelectric multidimensional force sensor, such as Figure 6As shown, it includes: a piezoelectric thin film 2-2 and an electrode array disposed on the piezoelectric thin film (i.e., an upper electrode array 2-1 and a lower electrode array 2-3 disposed on both sides of the piezoelectric thin film 2-2); the electrode array includes six electrode elements, respectively denoted as the first electrode element to the sixth electrode element; each electrode element includes a pair of upper and lower electrode elements; the upper electrode element and the lower electrode element are respectively disposed on both sides of the piezoelectric thin film and are in corresponding positions; the piezoelectric thin film 2-2 includes a first detection area and a second contact area and a second detection area disposed on both sides of the first detection area; the first detection area corresponding to the upper electrode array 2-1 includes the first upper electrode element A1 to the fourth upper electrode element B2; the second detection area corresponding to the upper electrode array 2-1 includes the fifth upper electrode element C1 and the sixth upper electrode element C2.

[0063] When the piezoelectric film 2-2 is wrapped on the surface of the rod 1 to measure multidimensional forces, the first upper electrode element A1 to the fourth upper electrode element B2 are arranged along the circumference of the rod, and the adjacent upper electrode elements are equally spaced; the fifth upper electrode element C1 and the sixth upper electrode element C2 are arranged symmetrically with the second upper electrode element B1 and the third upper electrode element A2 along the same axis of symmetry.

[0064] The lower electrode array 2-3 includes a first lower electrode element A1' to a sixth lower electrode element C2'; the positions of the first lower electrode element A1' to the sixth lower electrode element C2' are set to correspond one-to-one with the positions of the first upper electrode element A1 to the sixth upper electrode element C2.

[0065] The fifth and sixth electrode elements adopt a parallel integral connection structure.

[0066] The first upper electrode element A1 to the fourth upper electrode element B2, the first lower electrode element A1' to the fourth lower electrode element B2', the fifth lower electrode element C1' and the sixth upper electrode element C2 are respectively connected to the ten contacts of the second contact area.

[0067] This embodiment employs a sensing array 2 derived from Embodiment 1. Unlike Embodiment 1, each independent front and back electrode element is directly connected to the signal input of the readout circuit 3, with differential or integral operations moved to the back-end circuitry. This architecture supports independent configuration of signal conditioning circuits or grounding strategies for each element, granting the system high signal processing flexibility. However, this approach leads to a significant increase in the number of interfaces and circuit complexity, thus it is primarily suitable for specific scenarios requiring independent analysis and study of the response characteristics of individual elements, such as in-depth performance characterization during sensor development or calibration.

[0068] The signals output from the first and third electrode elements are used to measure the deflection force in the X direction after differential operation in the back-end circuit. The signals output from the second and fourth electrode elements are used to measure the deflection force in the Y direction after differential operation in the back-end circuit. The signals output from the fifth and sixth electrode elements are used to measure the axial force in the Z direction after integral operation in the back-end circuit.

[0069] For similarities between this embodiment and Embodiment 1, please refer to the corresponding description in Embodiment 1, such as the preparation of the piezoelectric thin film 2-2 array, electrode wiring requirements, and surface element size requirements.

[0070] Example 3 This embodiment provides a flexible conformal piezoelectric multidimensional force sensor, such as Figure 7 As shown, it includes: a piezoelectric thin film 2-2 and an electrode array disposed on both sides of the piezoelectric thin film; the electrode array includes N+1 electrode arrays; the piezoelectric thin film 2-2 includes a first detection area and a third contact area and a third detection area disposed on both sides of the first detection area; the first detection area includes an electrode array; the third detection area includes N of the electrode arrays; N≥1.

[0071] Each electrode element group includes a first electrode element to a fourth electrode element; each electrode element includes an upper and lower electrode element pair; the upper electrode element and the lower electrode element are respectively disposed on two sides of the piezoelectric film and are in corresponding positions.

[0072] When measuring multidimensional forces by coating the surface of the object under test with a piezoelectric film, the first to fourth electrode elements are arranged along the circumference of the object under test, and adjacent electrode elements are set at equal intervals.

[0073] For each electrode element group, the first and third electrode elements, and the second and fourth electrode elements adopt a series differential connection structure.

[0074] Each upper electrode element in the first and third detection areas is connected to M contacts in the third contact area; M=4 (N+1).

[0075] like Figure 7 As shown, the electrode array includes an upper electrode array 2-1 and a lower electrode array 2-3 disposed on both sides of the piezoelectric film 2-2. Each electrode element group of the upper electrode array 2-1 includes a first upper electrode element A1 to a fourth upper electrode element B2. When the piezoelectric film 2-2 covers the surface of the rod 1 to be measured to measure multidimensional forces, the first upper electrode element A1 to the fourth upper electrode element B2 are arranged along the circumference of the rod to be measured, and adjacent upper electrode elements are equally spaced.

[0076] The positions of each lower electrode element in the lower electrode array 2-3 correspond one-to-one with the positions of the first upper electrode element A1 to the fourth upper electrode element B2 in the upper electrode array 2-1.

[0077] This embodiment represents another extension of the area array design concept. Its core lies in supporting flexible expansion of the number and layout of area elements according to specific user needs. In addition to the basic area element group (such as A1 / A1', B1 / B1', A2 / A2', B2 / B2') used for detecting deflection forces Fx / Fy, additional area arrays with the same structure can be added (e.g., Figure 7 (The D and E in the diagram represent structures, etc.). This modular expansion capability enables it to adapt to more complex multidimensional force (such as torque, local deflection force changes, etc.) or strain / stress measurement needs, significantly improving the sensor's adaptability and functionality in diverse application scenarios. For example, [the following text appears to be incomplete and requires further context: "will..."] Figure 7 The sensor is wrapped around the rod under test. Surface elements A1 / A1' and A2 / A2' measure the deflection force Fx at corresponding positions, and surface elements B1 / B1' and B2 / B2' measure the deflection force Fy at corresponding positions. In the structure indicated by D, the corresponding surface elements also measure the deflection forces Fx and Fy at corresponding positions. Similarly, in the structure indicated by E, the corresponding surface elements also measure the deflection forces Fx and Fy at corresponding positions. Therefore, by comparing the deflection forces Fx and Fy at different positions along the axial direction, the variation of the deflection forces Fx / Fy at local positions can be determined. By subtracting the measurement results of the surface elements at corresponding positions in different electrode surface element groups, it can be determined whether torque has been generated. Then, the specific torque value is calculated using a corresponding torque decoupling algorithm. For example, ... Figure 7 The sensor is wrapped around the test rod with different surface materials. The surface elements A1 / A1' and A2 / A2', as well as the surface elements in the structure indicated by D and E, are respectively set on the surface of the rod with different materials, so as to understand the difference in deflection force generated by the rod under different materials.

[0078] For details regarding the first to fourth electrode elements in this embodiment, please refer to the corresponding descriptions in Embodiment 1, such as the fabrication of the piezoelectric thin film 2-2 array, electrode wiring requirements, and element size requirements.

[0079] Example 4 This embodiment provides a readout circuit 3 for the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 1. This is a near-in-situ readout circuit 3, which uses a high-input-impedance, low-noise junction field-effect transistor (JFET) as its core amplification element. Figure 8In sections I and II, a convergent signal access architecture with "one pole entering the conditioning path and the other pole grounded" was constructed through system-level structured circuit design and unified modeling of "array-channel" access mapping. This architecture significantly reduces the number of external leads and interfaces, and suppresses inter-channel coupling and transmission loss. Combined with a multi-layer shielded network design with common reference grounding and a channel-level independent parameter adjustable mechanism, low-noise, high-interference-resistant collaborative readout of multiple signals is achieved while ensuring high integration and compact packaging. Figure 8 The design of the flexible coupling structure between the flexible piezoelectric array and the near-in-situ readout circuit 3 is shown, along with its equivalent circuit diagram. Figure 8 (a) in the diagram is the hardware structure diagram of the readout circuit 3. Figure 8 (b) in the diagram illustrates the principle of the readout circuit 3.

[0080] like Figure 8 As shown, the flexible readout circuit 3 adopts a functional partition structure, including a signal output interface area 3-1, a conditioning circuit area 3-2, and a signal input interface area 3-3. It is implemented based on a flexible printed circuit board (FPC) and miniaturized surface-mount components. Through three-dimensional layout optimization and space compression technology, the circuit's flexibility and integration are significantly improved, meeting the near-in-situ mounting requirements with strict limitations on device size and weight.

[0081] The readout circuit 3 and the sensing array 2 are jointly designed and integrated. Figure 8 The sensing array 2 in this application is a typical but non-limiting embodiment.

[0082] In the signal input interface area 3-3 (the area corresponding to CONN1), multiple standardized interfaces specifically designed for array signal coupling are included, such as signal conditioning channel interfaces P1 (CH1), P3 (CH2), and P5 (CH3), and their corresponding array ground ports P2 (CH1), P4 (CH2), and P6 (CH3). In addition, redundant shielded ground interfaces G2 and G3 are provided to enhance the reliability of mechanical connections and the redundancy of electromagnetic shielding. This interface adopts a symmetrical double-sided electrode layout, compatible with both front and back surface mounting methods of the array, and adaptable to positive and negative piezoelectric signals generated by piezoelectric films 2-2 with different polarization directions, improving the flexibility of system deployment. Figure 8 As shown, as an example, rectangular metal patches are set at the positions marked G2 and G3. One end of the metal patch is connected to the circuit ground layer on the flexible printed circuit board corresponding to the signal readout circuit. When the sensor is attached to the surface of the rod under test, the rod under test and the circuit ground layer are grounded through the metal patch.

[0083] The signal input interface area 3-3 is equipped with an interface leakage protection area 3-3-1 and an interface electrode through hole 3-3-2.

[0084] Among them, interfaces P1~P4 and P6 are used to communicate with sensing array 2 (see Figure 8 The standardized electrode interfaces (contacts) located on the same plane are connected, and interface P5 is dedicated to the signal input of the reverse electrode elements of sensing array 2; each group of interfaces is connected by metallized through-holes (such as... Figure 8 Centered on 3-3-2, the circuit extends outward in a radial pattern to interconnect with the array electrodes using the shortest possible lead path, minimizing parasitic inductance and capacitance of the connection loop, ensuring high-frequency signal integrity and low-loss transmission of weak charge signals. Conditioning circuit area 3-2 includes circuit ground layer 3-2-1, power supply input terminal 3-2-2, and ground input terminal 3-2-3.

[0085] Shielded ground interface ( Figure 8 G2 and G3 in the diagram can share a common ground with the conductive measured rod, and are further connected to the circuit ground layer 3-2-1, the electrical ground interface G1, and the local ports (P2, P4, P6), forming a multi-layered common ground shielding network covering "measured rod 1—sensing array 2—readout circuit 3—system ground," which greatly suppresses common-mode noise and electromagnetic interference. Existing shielding strategies generally wrap a shielding metal film around the outside of the sensor, which can only shield external interference, but cannot effectively prevent interference inside the measured rod. This application can effectively suppress internal interference of the measured rod by adopting a multi-layered common ground shielding network, and can also suppress external interference to a certain extent. However, to more effectively suppress external interference, a shielding metal film can be introduced on the basis of the multi-layered common ground shielding network of this application, so as to avoid internal and external interference to the greatest extent and improve the reliability of signal acquisition.

[0086] Conditioning circuit section 3-2 (3-2) innovatively introduces an independently adjustable conditioning capacitor C at the gate of each channel, based on the single-channel JFET source follower. ij (i,j=1,2,3, e.g.) Figure 8 (such as C11, C21, and C31 in the model), enabling fine-tuning of the channel-by-channel joint array for key output characteristics: (1) Array-circuit joint gain conditioning: Assume the equivalent response voltage of a single array element pair is Rv (or the array element group in series: 2Rv), and consider the array parasitic capacitance C. fi (i=1,2,3) and circuit parasitic capacitance C ci Based on (i=1,2,3), the capacitor C is set by introducing the conditioning function (III). ij Jointly designed intrinsic capacitor C e The voltage output gain of each channel can be precisely controlled. (8) This conditioning mechanism supports independent calibration and matching of the sensitivity of face elements or face element groups with different sensitivity or different response requirements, enabling flexible and coordinated configuration among multiple channels.

[0087] The voltage output gain of each signal output interface of the readout circuit is determined by the conditioning capacitor C of the readout circuit. ij and surface element capacitor C e The size is adjusted accordingly.

[0088] (2) Bandwidth and holding characteristic conditioning: conditioning capacitor ( Figure 8 As shown in Figure III) and the gate resistor ( Figure 8 (As shown in II) they form a parallel relationship. Figure 10 and Figure 11 Similarly, the circuit shown also works together to achieve bandwidth and hold characteristic conditioning of the piezoelectric response signal.

[0089] Low-frequency poles of bandwidth The retention characteristic is determined by the time constant τ: (9) (10) That is, it can be mainly composed of conditioning capacitor C ij With gate resistance R i1 (corresponding to) Figure 8 The hold time of the signal is jointly conditioned by R11, R21, and R31. This allows for adjustment of the piezoelectric response from quasi-static (or long-term hold) to dynamic, depending on the detection requirements.

[0090] The signal output interface area 3-1 (CONN2) adopts a highly integrated and standardized design, with only three signal output terminals O1, O2, and O3 (corresponding to CH1, CH2, and CH3 respectively), a unified power supply interface V1, and a common ground processing interface G1. Under the premise of ensuring the signal integrity and power supply stability of the entire system, the number of interfaces and volume occupation are minimized, and rapid docking with the back-end acquisition system is supported.

[0091] The readout circuit 3 achieves near-in-situ coupling with the sensing array 2 via a flexible connection, and constructs a signal loop using the convergence principle of "one pole entering the conditioning path and the other pole grounded". Specifically, through interfaces P1 and P2, a piezoelectric differential conditioning loop is formed with the series elements A-1 and A-2 in the sensing array 2 of the sensor array region 3-4; through interfaces P3 and P4, a differential conditioning loop is formed with the series elements B-1 and B-2 in the sensing array 2; and through interfaces P4 and P5, an integral conditioning loop is formed with the parallel element group C-1 and C-2 in the sensing array 2. The above three sets of array elements only require three conditioning circuits for independent conditioning and readout, and the number of interfaces is simplified to 6, greatly realizing the miniaturization and flexibility of the flexible circuit. Figure 8 In the diagram, A-1 refers to the first electrode element, A-2 refers to the third electrode element, B-1 refers to the second electrode element, B-2 refers to the fourth electrode element, C-1 refers to the fifth electrode element, and C-2 refers to the sixth electrode element.

[0092] The described "circuit-area array" system possesses excellent flexibility and conformal capability, allowing it to be attached to complex curved surfaces for in-situ measurements. The overall bending state is as follows: Figure 9 As shown, it is applicable to typical application scenarios such as robot joints, precision machining tools, and wearable devices.

[0093] Based on the above, such as Figure 8 As shown in (b) in this embodiment, the readout circuit 3 includes three first readout sub-circuits; each first readout sub-circuit has the same structure.

[0094] Each first readout sub-circuit includes: a conditioning capacitor (corresponding to...) Figure 8 C11, C21, C31), junction field-effect transistor (corresponding to ... Figure 8 Q11, Q21, Q31), gate resistor (corresponding to) Figure 8 R11, R21, R31), source resistor (corresponding to Figure 8 R12, R22, R32) and drain resistor (corresponding to Figure 8 (R13, R23, R33 in the text).

[0095] The conditioning capacitor and the gate resistor are connected in parallel; one end of the gate resistor is connected to the gate of the junction field-effect transistor (JFET), and the other end of the gate resistor is grounded. The drain of the JFET is connected to the power interface through the drain resistor, and the source of the JFET is grounded through the source resistor. The source of the JFET is also connected to the signal output interface.

[0096] The two ends of the conditioning capacitor of the first readout sub-circuit are respectively connected to the contacts connected to the third upper electrode surface element A2 and the first upper electrode surface element A1 in the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 1.

[0097] The two ends of the conditioning capacitor of the second first readout sub-circuit are respectively connected to the contacts connected to the fourth upper electrode surface element B2 and the second upper electrode surface element B1 in the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 1.

[0098] The two ends of the conditioning capacitor of the third first readout sub-circuit are respectively connected to the contacts connected to the fifth lower electrode element C1' and the sixth upper electrode element C2 in the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 1.

[0099] This application achieves coordinated design of the array and circuitry, along with multi-physics joint optimization. By establishing a mapping relationship between the array topology and circuit access, and employing a convergent signal introduction strategy of "one pole conditioning, one pole grounding," combined with multi-layer common ground shielding and port collaborative management, parasitic parameters and channel coupling are effectively suppressed. Through multi-physics methods such as electrode alignment tolerance design, trace crossing to avoid parasitic capacitance, and strain transfer path control, the signal chain consistency, linearity, and dynamic response performance are comprehensively improved. The system supports independent adjustment of channel-level gain, bandwidth, and time constant, ensuring high-quality acquisition of both dynamic and quasi-static signals.

[0100] This application demonstrates excellent environmental adaptability and engineering application value. The sensor can conformally attach to the surface of rods made of various materials without damaging the original structure, making it suitable for long-term stable monitoring. Its standardized interface supports rapid deployment and system integration, significantly reducing the integration complexity and maintenance costs of three-dimensional force measurement systems in high-end equipment, and enhancing the practicality and scalability of the technical solution.

[0101] Example 5 This embodiment provides another readout circuit for the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 1, such as... Figure 10 As shown, it includes: three second readout sub-circuits; each second readout sub-circuit has the same structure.

[0102] Each readout sub-circuit includes a first circuit group and a second circuit group; the first circuit group and the second circuit group have the same structure.

[0103] Each first circuit group includes: a conditioning capacitor (corresponding to...) Figure 10 CA11 and CA21), junction field-effect transistors (corresponding to) Figure 10 QA11 and QA21 in the middle), gate resistor (corresponding to Figure 10 RA11 and RA21, source resistor (corresponding to) Figure 10 RA12 and RA22) and drain resistor (corresponding to Figure 10 (RA13 and RA23 in the middle).

[0104] The conditioning capacitor and the gate resistor are connected in parallel; one end of the gate resistor is connected to the gate of the junction field-effect transistor (JFET), and the other end of the gate resistor is grounded. The drain of the JFET is connected to the power interface through the drain resistor, and the source of the JFET is grounded through the source resistor. The source of the JFET is also connected to the signal output interface.

[0105] The gates of the junction field-effect transistors in the first and second circuit groups of the first second readout sub-circuit are also connected to the contacts connected to the first upper electrode surface element A1 and the third upper electrode surface element A2, respectively.

[0106] The gates of the junction field-effect transistors in the first and second circuit groups of the second second readout sub-circuit are also connected to the contacts connected to the second upper electrode element B1 and the fourth upper electrode element B2, respectively.

[0107] The gates of the junction field-effect transistors in the first and second circuit groups of the third second readout sub-circuit are also connected to the contacts connected to the fifth lower electrode element C1' and the sixth upper electrode element C2, respectively.

[0108] Figure 10 C in cA1 and C cA2 This refers to the parasitic capacitance of the circuit.

[0109] In this embodiment, to meet the specific needs of signal analysis in different application scenarios, the original grounded interface pole is changed to a signal conditioning pole, forming a differential input architecture with "bipolar conditioning". Figure 10 The number of interfaces remains the same, but the number of channels is expanded to 6, which can support measurement needs with higher common-mode rejection ratio and better noise performance. Figure 10 The diagram only shows the connection of the two conditioning channel interfaces (PA11 and PA21) corresponding to the first and third electrode elements to the readout circuit 3. For the connection methods of other interfaces, please refer to [reference needed]. Figure 10 That's all.

[0110] For similarities between this embodiment and Embodiment 5, please refer to the corresponding description in Embodiment 5, such as the design of the common ground shielding network, the joint gain conditioning of the array-circuit, and the bandwidth and retention characteristic conditioning.

[0111] Example 6 This embodiment provides a readout circuit 3 for the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 2, such as... Figure 11 As shown, it includes: five first readout sub-circuits; each first readout sub-circuit has the same structure.

[0112] Each first readout sub-circuit includes: a conditioning capacitor (corresponding to...) Figure 11 CA11 and CA21), junction field-effect transistors (corresponding to) Figure 11QA11 and QA21 in the middle), gate resistor (corresponding to Figure 11 RA11 and RA21, source resistor (corresponding to) Figure 11 RA12 and RA22) and drain resistor (corresponding to Figure 11 (RA13 and RA23 in the middle). Figure 11 In the middle, C f1-A1 C represents the parasitic capacitance corresponding to the first electrode element A-1 in the sensing array 2 in Example 2. f1-A2 This refers to the parasitic capacitance corresponding to the first electrode element A-2 in the sensing array 2 in Example 2. Figure 11 C in cA1 and C cA2 This refers to the parasitic capacitance of the circuit.

[0113] The conditioning capacitor and the gate resistor are connected in parallel; one end of the gate resistor is connected to the gate of the junction field-effect transistor (JFET), and the other end of the gate resistor is grounded. The drain of the JFET is connected to the power interface through the drain resistor, and the source of the JFET is grounded through the source resistor. The source of the JFET is also connected to the signal output interface.

[0114] The two ends of the conditioning capacitor of the first first readout sub-circuit are respectively connected to the contacts connected to the first upper electrode surface element A1 and the first lower electrode surface element A1' in the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 2.

[0115] The two ends of the conditioning capacitor of the second first readout sub-circuit are respectively connected to the contacts connected to the second upper electrode surface element B1 and the second lower electrode surface element B1' in the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 2.

[0116] The two ends of the conditioning capacitor of the third first readout sub-circuit are respectively connected to the contacts connected to the third upper electrode surface element A2 and the third lower electrode surface element A2' in the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 2.

[0117] The two ends of the conditioning capacitor of the fourth first readout sub-circuit are respectively connected to the contacts connected to the fourth upper electrode surface element B2 and the fourth lower electrode surface element B2' in the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 2.

[0118] The two ends of the conditioning capacitor of the fifth first readout sub-circuit are respectively connected to the contacts connected to the fifth upper electrode surface C1 and the sixth lower electrode surface C2' in the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 2.

[0119] This application provides a dedicated conditioning pathway for each individual surface element. Figure 11 It still adopts the convergent access method, expands the number of interfaces to 10, and increases the conditioning channels to 5, which is suitable for surface-level signal feature analysis and calibration scenarios. Figure 11 The diagram only shows the connection of the four conditioning channel interfaces (PA11, PA12, PA21, PA22) corresponding to the first and third electrode elements to the readout circuit 3. For the connection methods of other interfaces, please refer to [reference needed]. Figure 11 That's all.

[0120] For similarities between this embodiment and Embodiment 5, please refer to the corresponding description in Embodiment 5, such as the design of the common ground shielding network, the joint gain conditioning of the array-circuit, and the bandwidth and retention characteristic conditioning.

[0121] Example 7 This embodiment provides a readout circuit 3 for the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 3, comprising: 2 (N+1) first readout sub-circuits; each first readout sub-circuit has the same structure.

[0122] Each first readout sub-circuit includes: a conditioning capacitor, a junction field-effect transistor, a gate resistor, a source resistor, and a drain resistor.

[0123] The conditioning capacitor and the gate resistor are connected in parallel; one end of the gate resistor is connected to the gate of the junction field-effect transistor (JFET), and the other end of the gate resistor is grounded. The drain of the JFET is connected to the power interface through the drain resistor, and the source of the JFET is grounded through the source resistor. The source of the JFET is also connected to the signal output interface.

[0124] In the flexible conformal piezoelectric multidimensional force sensor described in Example 3, each electrode surface element corresponds to two first readout sub-circuits.

[0125] For each electrode element group, the two ends of the conditioning capacitor of the first readout sub-circuit are respectively connected to the contacts of the third upper electrode element A2 and the first upper electrode element A1 in the corresponding electrode element group.

[0126] The two ends of the conditioning capacitor of the second first readout sub-circuit are respectively connected to the contacts of the fourth upper electrode element B2 and the second upper electrode element B1 in the corresponding electrode element group.

[0127] For similarities between this embodiment and Embodiment 5, please refer to the corresponding description in Embodiment 5, such as the design of the common ground shielding network, the joint gain conditioning of the array-circuit, and the bandwidth and retention characteristic conditioning.

[0128] Example 8 This embodiment provides a flexible conformal piezoelectric multidimensional force sensor, including: the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 1 and the readout circuit 3 described in Embodiment 4.

[0129] For details regarding the sensor and readout circuit in this embodiment, please refer to the relevant descriptions in Embodiments 1 and 4.

[0130] In Example 4, the circuit ground layer, electrical ground interface in the signal output terminal, array grounding port, and the object under test of the flexible printed circuit board corresponding to the readout circuit are formed by a common grounding method to form a common ground shielding network; the array grounding port refers to the grounding contact when the flexible conformal piezoelectric multidimensional force sensor described in Example 1 is connected to the readout circuit of Example 4.

[0131] The voltage output gain of each signal output interface of the readout circuit described in Example 4 is adjusted according to the size of the conditioning capacitor and the surface element capacitor of the readout circuit; the surface element capacitor refers to the capacitor corresponding to each electrode surface element in the flexible conformal piezoelectric multidimensional force sensor described in Example 1.

[0132] The signal bandwidth and holding characteristics of each signal output interface of the readout circuit described in Example 4 are conditioned by the conditioning capacitor and gate resistor of the readout circuit.

[0133] This application establishes a complete "force-strain-piezoelectric response" decoupling conditioning model, from the "force-strain" mapping rod mechanical model (see Equations 3-7) to the "strain-piezoelectric response" conversion sensing model (see Equations 1-2), and the "area array-circuit" sensor response characteristic joint conditioning model (see Equations 8-10). Combined with the aforementioned mechanical decoupling process based on the area array structure, it ultimately establishes a complete "force-strain-piezoelectric response" decoupling conditioning model from external three-dimensional force input to final electrical signal conditioning and output.

[0134] By using parallel integral and series differential structures in the sensor array, multidimensional force decoupling and crosstalk between forces of different dimensions are achieved in the physical structure. In addition, the near-in-situ connection between the sensor and the readout circuit reduces parasitic capacitance, thereby improving signal transmission reliability, significantly improving the signal-to-noise ratio and measurement accuracy, and reducing dependence on complex back-end conditioning circuits.

[0135] This application designs a flexible conformal piezoelectric small-area array three-dimensional force sensor for high-precision, real-time, and synchronous measurement of three-dimensional force components (Fx, Fy, Fz) on the surface of rod-like components. To achieve force measurement, a three-dimensional force decoupling array (sensing array 2) and its corresponding near-in-situ readout circuit 3 are involved.

[0136] The readout circuit 3, centered on a high-input-impedance multi-channel front-end and structured circuitry, establishes a joint mapping relationship between the array topology and circuit access. It employs a convergent introduction strategy of "one pole entering the conditioning path, the other grounded," coupled with a multi-layer common-ground shielding network and port collaborative management, effectively reducing parasitic parameters and channel coupling. Furthermore, it provides a channel-level independent adjustable mechanism, allowing for on-demand configuration of parameters such as gain, bandwidth, signal hold, and time constant, ensuring high-quality readout of both dynamic and quasi-static signals. This achieves unified, synchronous, low-noise, and high-precision measurement of three-dimensional forces. Through multi-physics collaborative optimization (electrode alignment error compensation, parasitic capacitance minimization wiring, and controllable adjustment of strain transfer paths), it significantly improves the signal-to-noise ratio, linearity, and measurement consistency. Its compact and flexible structure is suitable for miniaturized deployment on flexible substrates. The established "force-strain-piezoelectric response" analytical model is adaptable to rods with different cross-sections, such as circular, square, and rectangular, and supports customized design of element size, layout orientation, and interface position, without weakening the original structural rigidity during conformal integration on complex curved surfaces. The sensor has a standardized electrical interface and distributed multi-channel synchronous acquisition capability, making it suitable for three-dimensional force sensing in high-end equipment such as precision machining equipment, robot joint force control, medical device mechanical monitoring, and spacecraft docking mechanisms.

[0137] Example 9 This embodiment provides a flexible conformal piezoelectric multidimensional force sensor, including: the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 1 and the readout circuit 3 described in Embodiment 5.

[0138] In Example 5, the circuit ground layer of the flexible printed circuit board corresponding to the readout circuit, the electrical ground interface in the signal output terminal, and the object under test are formed by a common grounding method to form a common ground shielding network.

[0139] The voltage output gain of each signal output interface of the readout circuit described in Example 5 is adjusted according to the size of the conditioning capacitor and the surface element capacitor of the readout circuit; the surface element capacitor refers to the capacitor corresponding to each electrode surface element in the flexible conformal piezoelectric multidimensional force sensor described in Example 1.

[0140] The signal bandwidth and holding characteristics of each signal output interface of the readout circuit described in Example 5 are conditioned according to the conditioning capacitor and gate resistor of the readout circuit.

[0141] For details regarding the sensor and readout circuit in this embodiment, please refer to the relevant descriptions in Embodiments 1 and 5.

[0142] Example 10 This embodiment provides a flexible conformal piezoelectric multidimensional force sensor, including: the flexible conformal piezoelectric multidimensional force sensor described in Embodiment 2 and the readout circuit 3 described in Embodiment 6.

[0143] In Example 6, the circuit ground layer, electrical ground interface in the signal output terminal, array grounding port, and the object under test of the flexible printed circuit board corresponding to the readout circuit are formed by a common grounding method to form a common ground shielding network; the array grounding port refers to the grounding contact when the flexible conformal piezoelectric multidimensional force sensor described in Example 2 is connected to the readout circuit of Example 6.

[0144] The voltage output gain of each signal output interface of the readout circuit described in Example 6 is adjusted according to the size of the conditioning capacitor and the surface element capacitor of the readout circuit; the surface element capacitor refers to the capacitor corresponding to each electrode surface element in the flexible conformal piezoelectric multidimensional force sensor described in Example 2.

[0145] The signal bandwidth and holding characteristics of each signal output interface of the readout circuit described in Example 6 are conditioned according to the conditioning capacitor and gate resistor of the readout circuit.

[0146] For details regarding the sensor and readout circuit in this embodiment, please refer to the relevant descriptions in Embodiments 2 and 6.

[0147] Example 11 This embodiment provides a flexible conformal piezoelectric multidimensional force sensor, including: the flexible conformal piezoelectric multidimensional force sensor described in embodiment 3 and the readout circuit 3 described in embodiment 7.

[0148] In Example 7, the circuit ground layer, electrical ground interface in the signal output terminal, array ground port, and the object under test of the flexible printed circuit board corresponding to the readout circuit are formed by a common grounding method to form a common ground shielding network; the array ground port refers to the grounding contact when the flexible conformal piezoelectric multidimensional force sensor described in Example 3 is connected to the readout circuit of Example 7.

[0149] The voltage output gain of each signal output interface of the readout circuit described in Example 7 is adjusted according to the size of the conditioning capacitor and the surface element capacitor of the readout circuit; the surface element capacitor refers to the capacitor corresponding to each electrode surface element in the flexible conformal piezoelectric multidimensional force sensor described in Example 3.

[0150] The signal bandwidth and holding characteristics of each signal output interface of the readout circuit described in Example 7 are conditioned according to the conditioning capacitor and gate resistor of the readout circuit.

[0151] For details regarding the sensor and readout circuit in this embodiment, please refer to the relevant descriptions in Embodiments 3 and 7.

[0152] The flexible conformal piezoelectric multidimensional force sensor and the corresponding readout circuit in Embodiments 8 to 11 above all adopt a near-in-situ connection method, which can greatly reduce the parasitic capacitance of the sensor and the readout circuit, improve sensitivity, greatly reduce noise interference, and improve the reliability of signal transmission.

[0153] Detailed descriptions of the same technical features in the above embodiments are also available in conjunction with each other. The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0154] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A flexible conformal piezoelectric multidimensional force sensor, characterized in that, include: A piezoelectric thin film and an electrode array disposed on the piezoelectric thin film; The electrode array comprises six electrode elements, denoted as the first electrode element to the sixth electrode element; Each electrode element includes a pair of upper and lower electrode elements; the upper electrode element and the lower electrode element are respectively disposed on two sides of the piezoelectric film and are in corresponding positions; The piezoelectric film includes a first detection area and a first contact area and a second detection area disposed on both sides of the first detection area; the first detection area includes a first electrode surface element to a fourth electrode surface element; the second detection area includes a fifth electrode surface element and a sixth electrode surface element. When a piezoelectric film is coated on the surface of the object to be measured to measure multidimensional forces, the first to fourth electrode elements are arranged along the circumference of the object to be measured, and adjacent electrode elements are set at equal intervals; the fifth and sixth electrode elements are arranged symmetrically with the second and third electrode elements along the same axis of symmetry. The first electrode element and the third electrode element, as well as the second electrode element and the fourth electrode element, adopt a series differential connection structure. The fifth and sixth electrode elements adopt a parallel integral connection structure; The upper electrode elements of the first to fourth electrode elements, the lower electrode element of the fifth electrode element, and the upper electrode element of the sixth electrode element are respectively connected to the six contacts of the first contact area.

2. The flexible conformal piezoelectric multidimensional force sensor according to claim 1, characterized in that, The upper and lower electrode elements of the fifth electrode element and the upper and lower electrode elements of the sixth electrode element each include multiple element blocks; the multiple element blocks are spaced apart and one side of two adjacent element blocks is connected. Alternatively, the upper and lower electrode elements of the fifth electrode element and the upper and lower electrode elements of the sixth electrode element can both be a single integral element. Alternatively, the upper electrode elements of both the fifth and sixth electrode elements include multiple element blocks; the multiple element blocks are spaced apart and one side of two adjacent element blocks is connected; the lower electrode elements of both the fifth and sixth electrode elements are a single integral element.

3. The flexible conformal piezoelectric multidimensional force sensor according to claim 1 or 2, characterized in that, The area of ​​each electrode element in the reverse electrode array is greater than or equal to the area of ​​each electrode element in the corresponding front electrode array; when the reverse electrode array is an array composed of upper electrode elements, the front electrode array is an array composed of lower electrode elements; when the reverse electrode array is an array composed of lower electrode elements, the front electrode array is an array composed of upper electrode elements.

4. A flexible conformal piezoelectric multidimensional force sensor, characterized in that, include: A piezoelectric thin film and an electrode array disposed on the piezoelectric thin film; The electrode array comprises six electrode elements, denoted as the first electrode element to the sixth electrode element; Each electrode element includes a pair of upper and lower electrode elements; the upper electrode element and the lower electrode element are respectively disposed on two sides of the piezoelectric film and are in corresponding positions; The piezoelectric film includes a first detection area and a second contact area and a second detection area disposed on both sides of the first detection area; the first detection area includes a first electrode surface element to a fourth electrode surface element; the second detection area includes a fifth electrode surface element and a sixth electrode surface element; When a piezoelectric film is coated on the surface of the object to be measured to measure multidimensional forces, the first to fourth electrode elements are arranged along the circumference of the object to be measured, and adjacent electrode elements are set at equal intervals; the fifth and sixth electrode elements are arranged symmetrically with the second and third electrode elements along the same axis of symmetry. The fifth and sixth electrode elements adopt a parallel integral connection structure; The upper and lower electrode elements of the first to fourth electrode elements, the lower electrode element of the fifth electrode element, and the upper electrode element of the sixth electrode element are respectively connected to the ten contacts of the second contact area.

5. A readout circuit for a flexible conformal piezoelectric multidimensional force sensor according to any one of claims 1 to 3, characterized in that, include: Three first readout sub-circuits; The structures of the first readout sub-circuits are identical; Each first readout sub-circuit includes: a conditioning capacitor, a junction field-effect transistor, a gate resistor, a source resistor, and a drain resistor; The conditioning capacitor and the gate resistor are connected in parallel; one end of the gate resistor is connected to the gate of the junction field-effect transistor (JFET), and the other end of the gate resistor is grounded. The drain of the JFET is connected to the power interface through the drain resistor, and the source of the JFET is grounded through the source resistor. The source of the JFET is also connected to the signal output interface. The two ends of the conditioning capacitor of the first readout sub-circuit are respectively connected to the contacts connected to the upper electrode surface of the third electrode element and the first electrode surface element. The two ends of the conditioning capacitor of the second first readout sub-circuit are respectively connected to the contacts connected to the upper electrode surface of the fourth electrode element and the second electrode element. The two ends of the conditioning capacitor of the third first readout sub-circuit are respectively connected to the contacts connected to the lower electrode surface of the fifth electrode surface and the upper electrode surface of the sixth electrode surface.

6. A readout circuit for a flexible conformal piezoelectric multidimensional force sensor according to any one of claims 1 to 3, characterized in that, include: Three second readout sub-circuits; each second readout sub-circuit has the same structure; Each readout sub-circuit includes a first circuit group and a second circuit group; The first circuit group and the second circuit group have the same structure; Each first circuit group includes: a conditioning capacitor, a junction field-effect transistor, a gate resistor, a source resistor, and a drain resistor; The conditioning capacitor and the gate resistor are connected in parallel; one end of the gate resistor is connected to the gate of the junction field-effect transistor (JFET), and the other end of the gate resistor is grounded. The drain of the JFET is connected to the power interface through the drain resistor, and the source of the JFET is grounded through the source resistor. The source of the JFET is also connected to the signal output interface. The gates of the junction field-effect transistors in the first and second circuit groups of the first and second readout sub-circuit are also connected to the contacts connected to the upper electrode elements of the first and third electrode elements, respectively. The gates of the junction field-effect transistors in the first and second circuit groups of the second second readout sub-circuit are also connected to the contacts connected to the upper electrode elements of the second and fourth electrode elements, respectively. The gates of the junction field-effect transistors in the first and second circuit groups of the third second readout sub-circuit are also connected to the contacts connected to the lower electrode element of the fifth electrode element and the upper electrode element of the sixth electrode element, respectively.

7. A readout circuit for the flexible conformal piezoelectric multidimensional force sensor according to claim 4, characterized in that, include: Five first-ever readout sub-circuits; The structures of the first readout sub-circuits are identical; Each first readout sub-circuit includes: a conditioning capacitor, a junction field-effect transistor, a gate resistor, a source resistor, and a drain resistor; The conditioning capacitor and the gate resistor are connected in parallel; one end of the gate resistor is connected to the gate of the junction field-effect transistor (JFET), and the other end of the gate resistor is grounded. The drain of the JFET is connected to the power interface through the drain resistor, and the source of the JFET is grounded through the source resistor. The source of the JFET is also connected to the signal output interface. The two ends of the conditioning capacitor of the first readout sub-circuit are respectively connected to the contacts connected to the upper electrode element and the lower electrode element of the first electrode element. The two ends of the conditioning capacitor of the second first readout sub-circuit are respectively connected to the contacts connected to the upper electrode element and the lower electrode element of the second electrode element. The two ends of the conditioning capacitor of the third first readout sub-circuit are respectively connected to the contacts connected to the upper electrode element and the lower electrode element of the third electrode element. The two ends of the conditioning capacitor of the fourth first readout sub-circuit are respectively connected to the contacts connected to the upper electrode element and the lower electrode element of the fourth electrode element. The two ends of the conditioning capacitor of the fifth first readout sub-circuit are respectively connected to the contacts connected to the upper and lower electrode elements of the fifth electrode element.

8. A flexible conformal piezoelectric multidimensional force sensor, characterized in that, include: The flexible conformal piezoelectric multidimensional force sensor according to any one of claims 1 to 3 and the readout circuit according to claim 5, or the flexible conformal piezoelectric multidimensional force sensor according to any one of claims 1 to 3 and the readout circuit according to claim 6, or the flexible conformal piezoelectric multidimensional force sensor according to claim 4 and the readout circuit according to claim 7. The signal output terminal of the flexible conformal piezoelectric multidimensional force sensor and the signal input terminal of the corresponding readout circuit are connected in near-in-situ.

9. The flexible conformal piezoelectric multidimensional force sensor according to claim 8, characterized in that, The circuit ground layer, electrical ground interface in the signal output terminal, array ground port, and the object under test of the flexible printed circuit board corresponding to the readout circuit according to any one of claims 5 to 7 form a common ground shielding network by adopting a common grounding method; the array ground port refers to the grounding contact when the flexible conformal piezoelectric multidimensional force sensor according to any one of claims 1 to 4 is connected to the corresponding readout circuit.

10. The flexible conformal piezoelectric multidimensional force sensor according to claim 8, characterized in that, The voltage output gain of each signal output interface of the readout circuit according to any one of claims 5 to 7 is adjusted according to the size of the conditioning capacitor and the surface element capacitor of the readout circuit; the surface element capacitor refers to the capacitor corresponding to each electrode surface element in the flexible conformal piezoelectric multidimensional force sensor according to any one of claims 1 to 4.

11. The flexible conformal piezoelectric multidimensional force sensor according to claim 8, characterized in that, The signal bandwidth and holding characteristics of each signal output interface of the readout circuit according to any one of claims 5 to 7 are conditioned according to the conditioning capacitor and gate resistor of the readout circuit.

Images