Surgical robot tail end three-dimensional force sensing mechanism and force measuring method

Abstract

The invention provides a surgical robot tail end three-dimensional force sensing mechanism and a force measurement method, and relates to the technical field of force measurement, and the surgical robot tail end three-dimensional force sensing mechanism comprises a first connecting end used for connecting a surgical instrument, a second connecting end used for connecting a surgical robot mechanical arm, and a first strain measurement unit arranged between the first connecting end and the second connecting end. The first strain measurement unit comprises a strain structure and a measurement assembly, the strain structure is provided with a first strain part, a second strain part and a third strain part, and the three strain parts are elastically deformed under acting force in a first direction, a second direction and a third direction which are perpendicular to one another; a first strain assembly, a second strain assembly and a third strain assembly of the measuring assembly are correspondingly installed on three strain parts, and the three components are matched to measure acting force borne by the surgical instrument in the first direction, the second direction and the third direction. The measurement limitation of a one-dimensional sensor is broken through, and the measurement of the acting force borne by the surgical instrument in three dimensions is realized.

Description

Technical Field

[0001] This invention relates to the field of force measurement technology, and in particular to a three-dimensional force sensing mechanism and a force measurement method for the end effector of a surgical robot. Background Technology

[0002] In UBE surgical robot systems, the force sensing function of the end effector is crucial. Its core lies in the integration of high-precision force sensors, which can accurately sense the force information of the interaction between surgical instruments and tissues, and convert it into electrical signals according to specific rules. This meets the requirements for real-time transmission, processing, storage, display, recording, and feedback control of force information during surgery. However, the force sensors commonly used in current UBE surgical robots can only detect single-dimensional forces. The interaction between surgical instruments and tissues involves complex, multi-dimensional mechanical behavior. One-dimensional sensors cannot fully capture these multi-dimensional mechanical states, making it difficult to meet the stringent requirements of force sensing accuracy in surgical robots. This leads to inaccurate operation by the surgical robot, ultimately affecting the surgical outcome.

[0003] Therefore, there is an urgent need for a three-dimensional force sensing mechanism and force measurement method at the end of a surgical robot to achieve the measurement of the force exerted by surgical instruments in three dimensions. Summary of the Invention

[0004] The purpose of this invention is to address the above problems by providing a three-dimensional force sensing mechanism at the end of a surgical robot and a method for measuring force.

[0005] In a first aspect, the present invention provides a three-dimensional force sensing mechanism at the end of a surgical robot, comprising: A first connecting end is used to connect surgical instruments; The second connection end is used to connect to the robotic arm of the surgical robot; A first strain measurement unit is disposed between the first connecting end and the second connecting end. The first strain measurement unit includes a strain structure and a measurement component. The strain structure has a first strain section, a second strain section, and a third strain section. The first strain section, the second strain section, and the third strain section undergo elastic deformation when subjected to forces along a first direction, a second direction, and a third direction, respectively. The first direction is perpendicular to the second direction and the third direction. The measurement component includes a first strain component, a second strain component, and a third strain component. The first strain component is disposed on the first strain section, the second strain component is disposed on the second strain section, and the third strain component is disposed on the third strain section. The first strain component, the second strain component, and the third strain component cooperate with each other to measure the forces subjected to the surgical instrument along the first direction, the second direction, and the third direction.

[0006] According to certain embodiments of the present invention, the strain structure includes: A first cavity and a second cavity are sequentially arranged along the third direction. The first cavity and the second cavity are separated from each other and are not connected. The side wall of the first cavity perpendicular to the first direction is the first strain section, the side wall of the first cavity perpendicular to the second direction is the second strain section, and the side wall of the second cavity perpendicular to the third direction is the third strain section.

[0007] According to the technical solutions provided by certain embodiments of the present invention, the first strain component, the second strain component, and the third strain component each include two strain gauge groups, each strain gauge group includes two strain gauges, and the two strain gauges in each strain gauge group of the first strain component, the second strain component, and the third strain component are respectively disposed on the inner and outer sides of the side wall where they are located. The strain gauges in the first strain assembly are electrically connected to form a first measurement circuit of the first strain measurement unit, the strain gauges in the second strain assembly are electrically connected to form a second measurement circuit of the first strain measurement unit, and the strain gauges in the third strain assembly are electrically connected to form a third measurement circuit of the first strain measurement unit. The first voltage output by the first measurement circuit, the second voltage output by the second measurement circuit, and the third voltage output by the third measurement circuit are used together to obtain the force exerted by the surgical instrument along the first direction, the second direction, and the third direction.

[0008] According to the technical solutions provided in some embodiments of the present invention, the sensing mechanism further includes a limiting member, one end of which is fixedly connected to the side of the second connecting end away from the robotic arm of the surgical robot, and the other end extends to a position close to the first connecting end and has a limiting gap with the first connecting end, for limiting the deformation of the sensing mechanism along the third direction.

[0009] According to certain embodiments of the present invention, the sensing mechanism further includes a second strain measurement unit. The structure of the second strain measurement unit is the same as that of the first strain measurement unit. The second strain measurement unit and the first strain measurement unit are symmetrically arranged with respect to the sensing mechanism along a third-direction axis. The vertical distance from the second strain measurement unit to the stress concentration point of the surgical instrument is greater than the vertical distance from the first strain measurement unit to the stress concentration point of the surgical instrument. The second strain measurement unit is used in conjunction with the first strain measurement unit to provide early warning of the depth of intervention of the surgical instrument on the operating object.

[0010] Secondly, the present invention provides a method for measuring three-dimensional force at the end effector of a surgical robot, comprising: S1. Collect the first voltage output by the first measurement circuit of the first strain measurement unit, the second voltage output by the second measurement circuit, and the third voltage output by the third measurement circuit, and generate a voltage signal matrix based on the first voltage, the second voltage, and the third voltage. S2. Input the voltage signal matrix and decoupling coefficient matrix into a linear regression model established based on the least squares method for decoupling operation to obtain a three-dimensional force matrix; the decoupling coefficient matrix is ​​obtained by performing a static calibration experiment on the sensing mechanism; S3. Based on the three-dimensional force matrix, determine the forces acting on the surgical instrument along the first direction, the second direction, and the third direction.

[0011] According to the technical solutions provided by certain embodiments of the present invention, the method prior to step S1 further includes: S0. Based on the geometric dimensions, material property parameters, and multiple sets of test force parameters of the three-dimensional force sensing mechanism at the end of the surgical robot, perform finite element simulation to obtain the target setting positions of the first strain component, the second strain component, and the third strain component, and paste the first strain component, the second strain component, and the third strain component to the corresponding target setting positions.

[0012] According to the technical solutions provided in some embodiments of the present invention, the method further includes: The first strain component, second strain component, and third strain component of the second strain measurement unit are respectively attached at their target setting positions symmetrical to the sensing mechanism along a third-direction axis.

[0013] According to the technical solutions provided in some embodiments of the present invention, the method further includes: While acquiring the first voltage output by the first measurement circuit of the first strain measurement unit, the second voltage output by the second measurement circuit, and the third voltage output by the third measurement circuit, the first voltage output by the first measurement circuit of the second strain measurement unit, the second voltage output by the second measurement circuit, and the third voltage output by the third measurement circuit are also acquired. The ratio of the first voltage, or the second voltage, or the third voltage corresponding to the first strain measurement unit and the second strain measurement unit is used as the intervention safety characteristic parameter; The system compares the intervention safety feature parameters with the safety threshold range and outputs corresponding warning messages based on the comparison results.

[0014] According to certain embodiments of the present invention, comparing interventional safety characteristic parameters with the safety threshold range of interventional safety characteristic parameters, and outputting corresponding early warning information based on the comparison result includes: If the intervention safety feature parameter is within the safety threshold range and continues to approach the boundary value of the safety threshold range within a preset time period, then the first warning message is output. If the intervention safety feature parameter exceeds the safety threshold range and the absolute value of the difference between the parameter and the boundary value of the safety threshold range is less than the first preset threshold, then a second warning message is output. If the rate of change of the intervention safety feature parameter within a preset time is greater than a preset rate of change threshold, or if the intervention safety feature parameter exceeds the safety threshold range and the absolute value of the difference between the threshold value and the boundary value of the safety threshold range is greater than or equal to the first preset threshold, then a third warning message will be output.

[0015] In summary, this invention provides a three-dimensional force sensing mechanism for the end effector of a surgical robot, comprising a first connecting end for connecting a surgical instrument; a second connecting end for connecting a robotic arm of the surgical robot; and a first strain measurement unit disposed between the first and second connecting ends. The first strain measurement unit includes a strain structure and a measurement component. The strain structure has a first strain portion, a second strain portion, and a third strain portion. The first strain portion, the second strain portion, and the third strain portion undergo elastic deformation when subjected to forces along a first direction, a second direction, and a third direction, respectively. The first direction is perpendicular to the second direction and the third direction. The measurement component includes a first strain component, a second strain component, and a third strain component. The first strain component is disposed at the first strain portion, the second strain component is disposed at the second strain portion, and the third strain component is disposed at the third strain portion. The first strain component, the second strain component, and the third strain component cooperate to measure the forces exerted by the surgical instrument along the first direction, the second direction, and the third direction.

[0016] This invention utilizes the elastic deformation of the first, second, and third strain sections of a first strain unit when subjected to forces along a first, second, and third direction. First, second, and third strain components are respectively attached to these strain sections. These components work together to measure the forces acting on the surgical instrument along the mutually perpendicular first, second, and third directions based on the elastic deformation of the corresponding strain sections. Compared to existing technologies, this invention overcomes the limitations of one-dimensional sensors, enabling the measurement of forces acting on surgical instruments in three dimensions.

[0017] It should be understood that the descriptions of technical features, technical solutions, beneficial effects, or similar language in this invention do not imply that all features and advantages can be achieved in any single embodiment. Rather, it is understood that the description of a feature or beneficial effect means that a specific technical feature, technical solution, or beneficial effect is included in at least one embodiment. Therefore, the descriptions of technical features, technical solutions, or beneficial effects in this specification do not necessarily refer to the same embodiment. Furthermore, the technical features, technical solutions, and beneficial effects described in this embodiment can be combined in any suitable manner. Those skilled in the art will understand that embodiments can be implemented without one or more specific technical features, technical solutions, or beneficial effects of a particular embodiment. In other embodiments, additional technical features and beneficial effects may be identified in specific embodiments that do not embody all embodiments. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a three-dimensional force sensing mechanism at the end of a surgical robot, provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the strain structure provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the measurement component provided in an embodiment of the present invention; Figure 4 A flowchart illustrating a method for measuring three-dimensional force at the end of a surgical robot according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the lever arm from the stress measurement unit to the stress concentration point provided in an embodiment of the present invention.

[0020] The text labels in the image represent: 1. First connecting end; 2. Second connecting end; 3. First strain measurement unit; 31. Strain structure; 311. First strain section; 312. Second strain section; 313. Third strain section; 32. Measurement assembly; 321. First strain assembly; 322. Second strain assembly; 323. Third strain assembly; 4. Limiting component; 5. Second strain measurement unit. Detailed Implementation

[0021] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. This description is merely illustrative and explanatory, and should not be construed as limiting the scope of protection of the present invention in any way. Specifically, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0022] It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or apparatus.

[0023] As mentioned in the background section, in view of the problems in the prior art, this embodiment provides a three-dimensional force sensing mechanism at the end of a surgical robot, comprising: First connecting end 1, the first connecting end 1 is used to connect surgical instruments; The second connection end 2 is used to connect the robotic arm of the surgical robot; The first strain measurement unit 3 is disposed between the first connecting end 1 and the second connecting end 2. The first strain measurement unit 3 includes a strain structure 31 and a measuring component 32. The strain structure 31 has a first strain section 311, a second strain section 312, and a third strain section 313. The first strain section 311, the second strain section 312, and the third strain section 313 undergo elastic deformation when subjected to forces along a first direction, a second direction, and a third direction, respectively. The first direction is perpendicular to the second direction and the third direction. The measuring component 32 includes a first strain component 321, a second strain component 322, and a third strain component 323. The first strain component 321 is disposed on the first strain section 311, the second strain component 322 is disposed on the second strain section 312, and the third strain component 323 is disposed on the third strain section 313. The first strain component 321, the second strain component 322, and the third strain component 323 cooperate with each other to measure the forces subjected to surgical instruments along the first direction, the second direction, and the third direction.

[0024] For details, please refer to Figure 1The first connecting end 1, the second connecting end 2, and the first strain measurement unit 3 located between the first connecting end 1 and the second connecting end 2 of the three-dimensional force sensing mechanism at the end of the surgical robot are all made of aerospace-grade aluminum alloy 7075, and the three are integrally formed. This aerospace-grade aluminum alloy 7075, after hard anodizing, possesses high strength, strong corrosion resistance, and stable mechanical properties. The integral forming process effectively reduces assembly errors and interference from external vibrations on the sensing mechanism, which is beneficial to improving the measurement accuracy of three-dimensional force. The first connecting end 1 is used to connect surgical instruments, which are the execution components that directly interact between the surgical robot and the manipulated object (such as human tissue). These instruments can be surgical needles or other surgical instruments, without specific limitations. The second connecting end 2 is connected to the robotic arm of the surgical robot. The two can be connected by bolts or other fixing methods, without specific limitations. The force exerted by the surgical instruments refers to the mechanical load generated when the instruments interact with the manipulated object (such as human tissue) during surgery, such as through puncture, cutting, lifting, and pressing, encompassing the force components in three-dimensional space. The first connection end 1 is the receiving end of the force applied by the surgical instrument, the first strain measurement unit 3 is the force signal conversion and detection end, and the second connection end 2 is the fixing end of the sensing mechanism, which is used to ensure the connection stability between the sensing mechanism and the surgical robot arm, so that the movement of the surgical instrument and the detection process of the first strain measurement unit 3 remain stable.

[0025] For details, please refer to Figure 1 , Figure 2 and Figure 3 The first strain measurement unit 3 includes a strain structure 31 and a measurement component 32. The strain structure 31 has a first strain section 311, a second strain section 312, and a third strain section 313. The first strain section 311, the second strain section 312, and the third strain section 313 undergo elastic deformation when subjected to forces along a first direction, a second direction, and a third direction, respectively. The first direction is perpendicular to the second direction and the third direction. The measurement component 32 includes a first strain component 321, a second strain component 322, and a third strain component 323. The first strain component 321 is disposed on the first strain section 311, the second strain component 322 is disposed on the second strain section 312, and the third strain component 323 is disposed on the third strain section 313. The first strain component 321, the second strain component 322, and the third strain component 323 cooperate to convert the elastic deformation of the first strain section 311, the second strain section 312, and the third strain section 313 into electrical signals, and obtain the forces exerted on the surgical instrument along the first direction, the second direction, and the third direction through data analysis and processing. The first direction is... Figure 1 The middle X-axis direction, the second direction is Figure 1 In the Y-axis direction, the third direction is Figure 1 In the Z-axis direction.

[0026] This invention utilizes the elastic deformation of the first, second, and third strain sections of a first strain unit when subjected to forces along a first, second, and third direction. First, second, and third strain components are respectively attached to these strain sections. These components work together to obtain the forces exerted by the surgical instrument along the mutually perpendicular first, second, and third directions based on the elastic deformation of the corresponding strain sections. This solves the problem of traditional force sensors only detecting single-dimensional forces, avoiding the inability of one-dimensional sensors to fully capture multi-dimensional mechanical states, which can lead to inadequate operation of the surgical robot and affect surgical efficacy.

[0027] In a preferred embodiment, the strain structure 31 includes: A first cavity and a second cavity are arranged sequentially along a third direction. The first cavity and the second cavity are separated from each other and are not connected. The side wall of the first cavity perpendicular to the first direction is the first strain section 311, the side wall of the first cavity perpendicular to the second direction is the second strain section 312, and the side wall of the second cavity perpendicular to the third direction is the third strain section 313.

[0028] Specifically, such as Figure 2 As shown, the strain structure 31 includes a first cavity and a second cavity arranged sequentially along a third direction. The first cavity and the second cavity are separated from each other and do not communicate with each other, so that the first strain section 311, the second strain section 312, and the third strain section 313 can have independent deformation space, avoiding mutual interference during force transmission. The sidewall of the first cavity perpendicular to the first direction is the first strain section 311, the sidewall of the first cavity perpendicular to the second direction is the second strain section 312, and the sidewall of the second cavity perpendicular to the third direction is the third strain section 313. Moreover, the strain section is directly formed by the sidewall of the cavity, which makes the sidewall structure thinner and lighter, with stronger elastic deformation capability, and can more accurately detect the force changes during the operation, improving the sensitivity of the sensing mechanism.

[0029] In a preferred embodiment, the first strain component 321, the second strain component 322, and the third strain component 323 each include two strain gauge groups, and each strain gauge group includes two strain gauges. The two strain gauges in each strain gauge group of the first strain component 321, the second strain component 322, and the third strain component 323 are respectively disposed on the inner and outer sides of the side wall where they are located. The strain gauges in the first strain assembly 321 are electrically connected to form the first measurement circuit of the first strain measurement unit 3. The strain gauges in the second strain assembly 322 are electrically connected to form the second measurement circuit of the first strain measurement unit 3. The strain gauges in the third strain assembly 323 are electrically connected to form the third measurement circuit of the first strain measurement unit 3. The first voltage output by the first measurement circuit, the second voltage output by the second measurement circuit, and the third voltage output by the third measurement circuit are used together to obtain the force exerted by the surgical instrument along the first direction, the second direction, and the third direction.

[0030] Specifically, such as Figure 3As shown, the first strain gauge assembly 321, the second strain gauge assembly 322, and the third strain gauge assembly 323 each include two strain gauge groups, and each strain gauge group includes two strain gauges. The two strain gauges in each strain gauge group of the first strain gauge assembly 321, the second strain gauge assembly 322, and the third strain gauge assembly 323 are respectively disposed on the inner and outer sides of their respective sidewalls. The strain gauges in the first strain gauge assembly 321 are electrically connected to form the first measurement circuit of the first strain measurement unit 3, the strain gauges in the second strain gauge assembly 322 are electrically connected to form the second measurement circuit of the first strain measurement unit 3, and the strain gauges in the third strain gauge assembly 323 are electrically connected to form the third measurement circuit of the first strain measurement unit 3. The first voltage output by the first measurement circuit, the second voltage output by the second measurement circuit, and the third voltage output by the third measurement circuit are used together to obtain the force exerted by the surgical instrument along the first direction, the second direction, and the third direction. In this embodiment, the electrical connections of the strain gauges in the first strain gauge assembly 321, the second strain gauge assembly 322, and the third strain gauge assembly 323 all adopt the form of a Wheatstone bridge, and the strain gauges in the first strain gauge assembly 321, the second strain gauge assembly 322, and the third strain gauge assembly 323 are all identical. By placing the two strain gauges in each strain gauge group on the inner and outer sides of its respective sidewall, and connecting the strain gauges in each strain gauge assembly into a Wheatstone bridge according to the positive and negative stress law, the influence of eccentric load on the accuracy of three-dimensional force measurement can be eliminated. That is, when an eccentric load is applied, the strain gauges on the inner and outer sides of the sidewall will produce resistance changes of equal magnitude and opposite direction due to the additional torque (tension on one side increases resistance, compression on the other side decreases resistance). Since the Wheatstone bridge has the characteristic of suppressing common-mode signals, these reverse resistance changes will cancel each other out in the bridge, thereby eliminating the additional interference signals caused by the eccentric load. Simultaneously, under the action of force in the target direction, the strain gauges inside and outside the sidewall will generate resistance changes in the same direction. After being combined according to the positive and negative stress law by the Wheatstone measuring bridge, these changes are amplified into effective voltage signals, ensuring that the output first voltage, second voltage, and third voltage accurately reflect the true magnitude and direction of the three-dimensional force, avoiding measurement deviations caused by eccentric loads, and ensuring the accuracy of three-dimensional force measurement. When the surgical instrument connected to the first connection end 1 of the sensing mechanism is subjected to external force during operation, the first strain unit 311, the second strain unit 312, and the third strain unit 313 will undergo elastic deformation under force, generating elastic strain. The first strain component 321, the second strain component 322, and the third strain component 323, respectively attached to the first strain unit 311, the second strain unit 312, and the third strain unit 313, convert the elastic strain into resistance values. Then, the resistance change is converted into voltage by the Wheatstone bridge. Finally, after data analysis and processing, the force exerted on the surgical instrument along the first, second, and third directions is obtained.

[0031] In a preferred embodiment, the sensing mechanism further includes a limiting member 4, one end of which is fixedly connected to the side of the second connecting end 2 away from the robotic arm of the surgical robot, and the other end extends to a position close to the first connecting end 1 and has a limiting gap with the first connecting end 1, for limiting the deformation of the sensing mechanism in a third direction.

[0032] Specifically, such as Figure 1 As shown, the limiting member 4 is T-shaped, with one end fixedly connected to the side of the second connecting end 2 away from the surgical robot's robotic arm, and the other end extending close to the first connecting end 1 with a limiting gap between them. This limits the deformation of the sensing mechanism along a third direction, preventing excessive deformation of the strain structure 31 and ensuring the measurement accuracy and service life of the sensing mechanism. In this embodiment, the limiting member 4 is also made of aerospace-grade aluminum alloy 7075, and it is integrally formed with the first connecting end 1 and the second connecting end 2, which improves the overall integrity and mechanical strength of the sensing mechanism.

[0033] In a preferred embodiment, the sensing mechanism further includes a second strain measurement unit 5. The structure of the second strain measurement unit 5 is the same as that of the first strain measurement unit 3. The second strain measurement unit 5 and the first strain measurement unit 3 are symmetrically arranged with respect to the sensing mechanism along a third-direction axis. The vertical distance from the second strain measurement unit 5 to the stress concentration point of the surgical instrument is greater than the vertical distance from the first strain measurement unit 3 to the stress concentration point of the surgical instrument. The second strain measurement unit 5 is used in conjunction with the first strain measurement unit 3 to provide early warning of the depth of intervention of the surgical instrument on the operating object.

[0034] Specifically, such as Figure 1As shown, the sensing mechanism also includes a second strain measurement unit 5. The structure of the second strain measurement unit 5 is the same as that of the first strain measurement unit 3, and the second strain measurement unit 5 and the first strain measurement unit 3 are symmetrically arranged relative to the sensing mechanism along a third-direction axis. The vertical distance from the second strain measurement unit 5 to the stress concentration point of the surgical instrument is greater than the vertical distance from the first strain measurement unit 3 to the stress concentration point of the surgical instrument. The second strain measurement unit 5 is used in conjunction with the first strain measurement unit 3 to provide early warning of the depth of intervention of the surgical instrument on the operating object. The stress concentration point of the surgical instrument changes with the depth of intervention on the operating object. When the intervention is shallow, the stress concentration point of the surgical instrument is closer to the end of the surgical instrument; as the intervention depth increases, the contact position between the surgical instrument and the operating object moves towards the sensing mechanism (i.e., the distance between the stress concentration point and the sensing mechanism shortens). The change in the stress concentration point of the surgical instrument causes a change in the distance between the first strain measurement unit 3 and the second strain measurement unit 5 and the stress concentration point of the surgical instrument, which in turn leads to a corresponding change in their output voltage. Therefore, the second strain measurement unit 5 can be used in conjunction with the first strain measurement unit 3 to characterize the change in intervention depth, thereby achieving early warning of the intervention depth of the surgical instrument operation. It can be understood that the three-dimensional force sensing mechanism at the end of the surgical robot is symmetrically equipped with two strain measurement units (i.e., the first strain measurement unit 3 and the second strain measurement unit 5). In actual surgical operations, since the posture of the instrument may change at any time according to the needs of the surgery, the strain measurement unit with a relatively larger vertical distance to the stress concentration point of the surgical instrument is designated as the second strain measurement unit 5, and correspondingly, the strain measurement unit with a relatively smaller vertical distance to the stress concentration point of the surgical instrument is designated as the first strain measurement unit 3.

[0035] like Figure 4 As shown, this embodiment also provides a method for measuring three-dimensional force at the end of a surgical robot, including: S1. Collect the first voltage output from the first measurement circuit of the first strain measurement unit 3, the second voltage output from the second measurement circuit, and the third voltage output from the third measurement circuit, and generate a voltage signal matrix based on the first voltage, the second voltage, and the third voltage; Specifically, the system collects the first voltage output from the first measurement circuit of the first strain measurement unit 3, the second voltage output from the second measurement circuit, and the third voltage output from the third measurement circuit. A voltage signal matrix is ​​generated based on these voltages. The purpose is to integrate the voltages corresponding to the three-dimensional force into a standardized matrix form, providing a unified raw data input for subsequent decoupling operations. For example, the voltage signal matrix is: ,in, This is the first voltage; This is the second voltage; This is the third voltage.

[0036] S2. Input the voltage signal matrix and decoupling coefficient matrix into the linear regression model established based on the least squares method for decoupling operation to obtain the three-dimensional force matrix; the decoupling coefficient matrix is ​​obtained by performing static calibration experiments on the sensing mechanism. Specifically, the voltage signal matrix and decoupling coefficient matrix are input into a linear regression model based on the least squares method for decoupling calculation to obtain a three-dimensional force matrix. The purpose is to eliminate measurement errors caused by factors such as processing errors of the elastic body and positioning deviations of strain gauges, and to separate and independent the force of the surgical instruments in three directions. Among them, the decoupling coefficient matrix is ​​obtained by performing a static calibration experiment on the sensing mechanism, and its calculation process is shown in formula (1): Formula (1) in, It is a voltage signal matrix; This is the decoupling coefficient matrix. , ... The sensitivity coefficients of each force component to the output voltage are given. It is a three-dimensional force matrix.

[0037] Because the first, second, and third measurement circuits in this embodiment have zero-point adjustment capabilities, the above formulas do not require the addition of a zero-point offset constant, and all sensitivity coefficients can be determined through static calibration experiments. Experiments show that after decoupling using the least squares method, the nonlinearity error of the three-dimensional force sensor within its measurement range is reduced to ±3%FS (Full Scale), the repeatability error is ≤5%FS, and the hysteresis error is ≤5%FS. This decoupling algorithm significantly improves the dynamic response and stability of three-dimensional force measurement, meeting the high-precision force feedback requirements of the surgical robot's end effector.

[0038] S3. Based on the three-dimensional force matrix, determine the forces acting on the surgical instruments along the first, second, and third directions.

[0039] Specifically, due to , and The effects on the sensing mechanism are all linear. Therefore, when three-dimensional forces act simultaneously on the three-dimensional force sensing mechanism, the stress and strain generated on the sensing mechanism can be considered as a linear superposition of the individual forces acting in each direction. , and When applied individually to surgical instruments mounted on a three-dimensional force sensing mechanism, the magnitudes of the changes in resistance values ​​of each strain gauge are defined as r1, r2, and r3, with the initial resistance value of each strain gauge being R. The resistance changes of the first, second, and third measurement circuits of the first strain measurement unit 3 under the action of three-dimensional force are summarized in the table below, where R1, R2, R3, and R4 are the resistances of the first measurement circuit; R5, R6, R7, and R8 are the resistances of the second measurement circuit; R9, R10, R11, and R12 are the resistances of the third measurement circuit, and E is the power supply voltage of the first, second, and third measurement circuits.

[0040] Table 1. Resistance variation under three-dimensional force components.

[0041] 1. direction When only When in operation, the output voltage of the first measuring circuit is as shown in the following formula (2): Formula (2) when , and When both are in operation, the output voltage of the first measuring circuit is as shown in the following formula (3): Formula (3) Since the changes in resistance values ​​r1, r2, and r3 of each strain gauge under three-dimensional external force are much smaller than the strain gauge's own resistance value R, it can be considered that the above formulas (2) and (3) are equal, that is, the first measuring circuit can independently measure the component force in the X direction. It will not be affected by forces from other directions.

[0042] 2. direction When only When in operation, the output voltage of the second measuring circuit is as shown in the following formula (4): Formula (4) when , and When both are in operation, the output voltage of the Y-direction measuring circuit is as shown in the following formula (5): Formula (5) Similarly, formulas (4) and (5) above can be considered equal, meaning that the second measuring circuit can independently measure the component force in the Y direction. It will not be affected by forces from other directions.

[0043] 3. direction When only When in operation, the output voltage of the third measuring circuit is as shown in the following formula (6): Formula (6) when , and When both circuits are in operation, the output voltage of the third measuring circuit is as shown in the following formula (7): Formula (7) Equations (6) and (7) above are equal, meaning that the third measuring circuit can independently measure the component force in the Z direction. It will not be affected by forces from other directions.

[0044] In summary, the first, second, and third measuring circuits can independently measure the force components in their corresponding directions. Therefore, the three-dimensional force matrix obtained through steps S1 and S2 already contains the independent forces acting on the surgical instrument along the first, second, and third directions. It is only necessary to directly extract the independent elements from the three-dimensional force matrix. , and This allows us to determine the magnitude of the force in the corresponding direction.

[0045] In a preferred embodiment, the method further includes the following steps prior to step S1: S0. Based on the geometric dimensions, material property parameters, and multiple sets of test force parameters of the three-dimensional force sensing mechanism at the end of the surgical robot, perform finite element simulation to obtain the target setting positions of the first strain component 321, the second strain component 322, and the third strain component 323, and paste the first strain component 321, the second strain component 322, and the third strain component 323 to the corresponding target setting positions.

[0046] Specifically, based on the geometric dimensions (e.g., length, width, thickness, etc.) and material property parameters (e.g., elastic modulus, Poisson's ratio, yield strength, etc.) of the three-dimensional force sensing mechanism at the end of the surgical robot, as well as multiple sets of test force parameters, finite element simulation is performed to obtain the target setting positions of the first strain gauge 321, the second strain gauge 322, and the third strain gauge 323. The first strain gauge 321, the second strain gauge 322, and the third strain gauge 323 are then pasted to their respective target setting positions (e.g., a coordinate system is established with any point on the sensing mechanism as the zero point, and the positions of the first strain gauge 321, the second strain gauge 322, and the third strain gauge 323 are represented by the three-dimensional coordinates in this coordinate system). Obtaining the target setting positions of the first strain gauge 321, the second strain gauge 322, and the third strain gauge 323 through simulation avoids the problems of insufficient strain gauge sensitivity and inaccurate three-dimensional force measurement results caused by blindly pasting the gauges, thus improving the accuracy of three-dimensional force measurement.

[0047] In a preferred embodiment, the method further includes: The first strain component 321, the second strain component 322, and the third strain component 323 of the first strain measurement unit 3 are respectively attached to the target setting positions of the first strain component 321, the second strain component 322, and the third strain component 323 of the second strain measurement unit 5 at positions symmetrical to the sensing mechanism along the third direction axis.

[0048] Specifically, the first strain component 321, the second strain component 322, and the third strain component 323 of the first strain measurement unit 3 are respectively attached to the target setting positions of the first strain component 321, the second strain component 322, and the third strain component 323 at positions symmetrical to the sensing mechanism along the third-direction axis. The purpose is to cooperate with the first strain component 321, the second strain component 322, and the third strain component 323 to provide early warning of the depth of surgical intervention of the surgical instrument on the object.

[0049] In a preferred embodiment, the method further includes: While acquiring the first voltage output by the first measurement circuit of the first strain measurement unit 3, the second voltage output by the second measurement circuit, and the third voltage output by the third measurement circuit, the first voltage output by the first measurement circuit of the second strain measurement unit 5, the second voltage output by the second measurement circuit, and the third voltage output by the third measurement circuit are also acquired. The ratio of the first voltage, or the second voltage, or the third voltage corresponding to the first strain measurement unit 3 and the second strain measurement unit 5 is used as the intervention safety characteristic parameter; The system compares the intervention safety feature parameters with the safety threshold range and outputs corresponding warning messages based on the comparison results.

[0050] Specifically, because the vertical distances from the second strain measurement unit 5 and the first strain measurement unit 3 of the sensing mechanism to the stress concentration point of the surgical instrument are different, and the vertical distance from the second strain measurement unit 5 to the stress concentration point of the surgical instrument is greater than the vertical distance from the first strain measurement unit 3 to the stress concentration point of the surgical instrument, such as Figure 5 As shown, the geometric center of the first strain component 321, the second strain component 322, and the third strain component 323 of the first strain measurement unit 3 is denoted as O1, the geometric center of the first strain component 321, the second strain component 322, and the third strain component 323 of the second strain measurement unit 3 is denoted as O2, and the stress concentration point of the surgical instrument is denoted as O3. The vertical distance between O1 and O3 is L1 (that is, the vertical distance from the first strain measurement unit 3 to the stress concentration point of the surgical instrument, which is also the lever arm length from the first strain measurement unit 3 to the stress concentration point), and the vertical distance between O2 and O3 is L2 (that is, the vertical distance from the second strain measurement unit 5 to the stress concentration point of the surgical instrument, which is also the lever arm length from the second strain measurement unit 5 to the stress concentration point), and L2 is greater than L1.

[0051] Therefore, when the surgical instrument is subjected to an external force F, the torque of the first strain measurement unit 3 is calculated as shown in the following formula (8): Formula (8) Where M1 is the torque borne by the first strain measurement unit 3; F is the force exerted on the surgical instrument; and L1 is the lever arm length from the first strain measurement unit 3 to the stress concentration point.

[0052] The torque of the second strain measurement unit 5 is calculated as shown in the following formula (9): Formula (9) Where M2 is the torque borne by the second strain measurement unit 5; F is the force exerted on the surgical instrument; and L2 is the lever arm length from the second strain measurement unit 5 to the stress concentration point.

[0053] Since the output voltage of the circuit is approximately linearly related to the strain, and thus linearly related to the torque, the output voltage of the first strain measuring unit 3 in any direction can be expressed as formula (10): Formula (10) Wherein, V1 is the output voltage of the first strain measurement unit 3; k1 is the sensitivity coefficient of the first strain measurement unit 3; M1 is the torque borne by the first strain measurement unit 3; F is the force exerted on the surgical instrument; and L1 is the lever arm length from the first strain measurement unit 3 to the stress concentration point.

[0054] The output voltage of the second strain measurement unit 5 in any direction is expressed by formula (11): Formula (11) Wherein, V2 is the output voltage of the second strain measurement unit 5; k2 is the sensitivity coefficient of the second strain measurement unit 5; M2 is the torque borne by the second strain measurement unit 5; F is the force exerted on the surgical instrument; and L2 is the lever arm length from the second strain measurement unit 5 to the stress concentration point.

[0055] Since the sensing mechanism is integrally formed, and the first strain component 321, the second strain component 322, the third strain component 323 of the first strain measurement unit 3 and the fourth strain component, the fifth strain component, and the sixth strain component of the second strain measurement unit 5 are arranged identically, therefore... Therefore, the voltage ratio of the first strain measurement unit 3 and the second strain measurement unit 5 is as shown in the following formula (12): Formula (12) in, V1 is the voltage ratio of the first strain measurement unit 3 and the second strain measurement unit 5; V2 is the output voltage of the first strain measurement unit 3; V2 is the output voltage of the second strain measurement unit 5; k1 is the sensitivity coefficient of the first strain measurement unit 3; k2 is the sensitivity coefficient of the second strain measurement unit 5; L1 is the lever arm length from the first strain measurement unit 3 to the stress concentration point; L2 is the lever arm length from the second strain measurement unit 5 to the stress concentration point.

[0056] Therefore, when the magnitude of the force When the location of the stress concentration point changes but remains unchanged, If it remains unchanged, then Unchanged; when the location of the stress concentration point changes, As it changes, The voltage ratio of the first strain measuring unit 3 and the second strain measuring unit 5 will also change accordingly, so the voltage ratio of the second strain measuring unit 5 can be used. It reflects the change in the geometric position of the stress concentration point, and the change in geometric position can reflect the depth of intervention of the surgical instrument on the object being operated on. Therefore, the depth of intervention of the surgical instrument on the object being operated on can be predicted by the voltage ratio of the first strain measurement unit 3 and the second strain measurement unit 5.

[0057] Based on the above derivation, the specific steps for providing early warning of the intervention depth of the surgical instrument on the operating object by using the voltage ratio of the first strain measurement unit 3 and the second strain measurement unit 5 are as follows: While acquiring the first voltage output from the first measurement circuit of the first strain measurement unit 3, the second voltage output from the second measurement circuit, and the third voltage output from the third measurement circuit, the first voltage output from the first measurement circuit of the second strain measurement unit 5, the second voltage output from the second measurement circuit, and the third voltage output from the third measurement circuit are also acquired. The ratio of the first voltage, or the second voltage, or the third voltage corresponding to the first strain measurement unit 3 and the second strain measurement unit 5 is used as the intervention safety characteristic parameter.

[0058] The system compares the intervention safety feature parameters with the safety threshold range and outputs corresponding warning messages based on the comparison results.

[0059] In a preferred embodiment, the intervention safety feature parameter is compared with the safety threshold range of the intervention safety feature parameter, and the corresponding early warning information is output based on the comparison result, including: If the intervention safety feature parameter is within the safety threshold range and continues to approach the boundary value of the safety threshold range within a preset time period, then the first warning message will be output. If the intervention safety feature parameter exceeds the safety threshold range and the absolute value of the difference between the parameter and the boundary value of the safety threshold range is less than the first preset threshold, then a second warning message will be output. If the rate of change of the intervention safety feature parameter within a preset time is greater than a preset rate of change threshold, or if the intervention safety feature parameter exceeds the safety threshold range and the absolute value of the difference between the intervention safety feature parameter and the boundary value of the safety threshold range is greater than or equal to a first preset threshold, then a third warning message will be output.

[0060] Specifically, the interventional safety characteristic parameters are calculated at each moment. If the interventional safety characteristic parameters are within the safety threshold range and continue to approach the boundary value of the safety threshold range within a preset time period, a first warning message is output to remind the operator that although the current interventional depth is within the safety threshold range, there is a risk of exceeding the safety threshold range because it continues to approach the boundary value of the safety threshold range. If the interventional safety characteristic parameters exceed the safety threshold range and the absolute value of the difference between them and the boundary value of the safety threshold range is less than a first preset threshold, a second warning message is output. The first preset threshold is a small value used to indicate that the interventional safety characteristic parameters slightly exceed the safety threshold range but are still within a controllable range. Active intervention can be used to bring them back to the safety threshold range. At this time, the control system can automatically reduce the feed speed or output force of the surgical robot according to the second warning message, or the operator can manually perform the intervention operation. If the rate of change of the interventional safety feature parameter within a preset time exceeds a preset rate of change threshold, or if the interventional safety feature parameter exceeds the safety threshold range and the absolute value of the difference between the parameter and the boundary value of the safety threshold range is greater than or equal to a first preset threshold, a third warning message will be output. This indicates that the interventional safety feature parameter has undergone a sudden change or exceeded the safety threshold range by too much, posing an extremely high operational risk. In this case, the surgical robot can be stopped based on the third warning message. In this embodiment, the first, second, and third warning messages can be displayed using different colored indicator lights or text, but the appropriate message can be selected based on the actual usage scenario; no specific limitation is made here.

[0061] This invention provides a three-dimensional force sensing mechanism for the end effector of a surgical robot. The mechanism utilizes the elastic deformation of the first, second, and third strain sections of a first strain unit under forces applied along a first, second, and third direction. First, second, and third strain components are respectively attached to these strain sections. These components work together to convert the elastic deformation of the corresponding strain sections into resistance values. A Wheatstone bridge is then used to convert the resistance changes into first, second, and third voltages, generating a voltage signal matrix. The voltage signal matrix and decoupling coefficient matrix are input into a linear regression model based on the least squares method for decoupling calculations to obtain a three-dimensional force matrix. Based on this force matrix, the forces exerted by the surgical instruments along the mutually perpendicular first, second, and third directions are obtained. This invention overcomes the limitation of traditional force sensors that can only detect forces in a single dimension, avoiding the problem of one-dimensional sensors failing to fully capture multi-dimensional mechanical states, which can lead to inaccurate operation of the surgical robot and affect surgical efficacy. By setting up a second strain measurement unit symmetrically distributed with the first strain measurement unit, the voltage signals corresponding to the first strain measurement unit and the second strain measurement unit are collected and the ratio is calculated. This ratio is used as an interventional safety characteristic parameter and compared with the safety threshold range to provide early warning of the intervention depth of the surgical instrument. This can promptly avoid the surgical risk of human tissue damage caused by excessive intervention, thereby improving the safety and reliability of the surgical robot operation.

[0062] To facilitate understanding by those skilled in the art, the workflow of the three-dimensional force sensing mechanism at the end of a surgical robot provided by this invention is as follows: The first connection end 1 of the sensing mechanism is connected to the surgical instrument, and the second connection end 2 is connected to the robotic arm of the surgical robot. The first strain component 321, the second strain component 322, and the third strain component 323 are pasted at the positions determined by finite element simulation, and the strain gauges are electrically connected to form the first measurement circuit, the second measurement circuit, and the third measurement circuit, respectively. When the surgical instrument comes into contact with the operating object and generates a three-dimensional force, the first strain section 311, the second strain section 312, and the third strain section 313 of the first strain measurement unit 3 undergo elastic deformation, which causes the strain gauges to generate resistance changes. These changes are converted into first voltage, second voltage, and third voltage through the corresponding first measurement circuit, second measurement circuit, and third measurement circuit, and a voltage signal matrix is ​​generated. The voltage signal matrix and the decoupling coefficient matrix obtained by static calibration are input into a linear regression model based on the least squares method for decoupling calculation to obtain a three-dimensional force matrix. The forces acting on the surgical instrument along the first, second, and third directions are obtained based on the three-dimensional force matrix. While acquiring the first voltage output from the first measurement circuit of the first strain measurement unit 3, the second voltage output from the second measurement circuit, and the third voltage output from the third measurement circuit, the same process is performed on the first voltage output from the first measurement circuit of the second strain measurement unit 5, and the third voltage output from the third measurement circuit. The ratio of the first voltage, or the second voltage, or the third voltage corresponding to the first strain measurement unit 3 and the second strain measurement unit 5 is used as an intervention safety characteristic parameter. This intervention safety characteristic parameter is compared with a safety threshold range. If the intervention safety characteristic parameter is within the safety threshold range and continuously approaches the boundary value of the safety threshold range within a preset time period, a first warning message is output. If the absolute value of the difference between the intervention safety characteristic parameter and the boundary value of the safety threshold range is greater than or equal to 0 and less than a first preset threshold, a second warning message is output. If the rate of change of the intervention safety characteristic parameter within a preset time period is greater than a preset rate of change threshold, or the absolute value of the difference between the intervention safety characteristic parameter and the boundary value of the safety threshold range is greater than or equal to the first preset threshold, a third warning message is output.

[0063] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. The above are only preferred embodiments of the present invention. It should be noted that due to the limitations of textual expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other occasions without modification, should all be considered within the scope of protection of the present invention.

Claims

1. A surgical robot end three-dimensional force sensing mechanism, characterized by, include: The first connecting end (1) is used to connect surgical instruments; The second connection end (2) is used to connect the robotic arm of the surgical robot; A first strain measurement unit (3) is disposed between the first connecting end (1) and the second connecting end (2). The first strain measurement unit (3) includes a strain structure (31) and a measurement component (32). The strain structure (31) has a first strain section (311), a second strain section (312), and a third strain section (313). The first strain section (311), the second strain section (312), and the third strain section (313) undergo elastic deformation when subjected to forces along a first direction, a second direction, and a third direction, respectively. The first direction is perpendicular to the second direction and the third direction. The measuring component (32) includes a first strain component (321), a second strain component (322), and a third strain component (323). The first strain component (321) is disposed on the first strain section (311), the second strain component (322) is disposed on the second strain section (312), and the third strain component (323) is disposed on the third strain section (313). The first strain component (321), the second strain component (322), and the third strain component (323) cooperate with each other to measure the force exerted on the surgical instrument along the first direction, the second direction, and the third direction.

2. The three-dimensional force sensing mechanism at the end of a surgical robot according to claim 1, characterized in that, The strain structure (31) includes: A first cavity and a second cavity are arranged sequentially along the third direction. The first cavity and the second cavity are separated from each other and are not connected. The side wall of the first cavity perpendicular to the first direction is the first strain section (311), the side wall of the first cavity perpendicular to the second direction is the second strain section (312), and the side wall of the second cavity perpendicular to the third direction is the third strain section (313).

3. The three-dimensional force sensing mechanism at the end of the surgical robot according to claim 2, characterized in that, The first strain assembly (321), the second strain assembly (322), and the third strain assembly (323) each include two strain gauge groups, and each strain gauge group includes two strain gauges. The two strain gauges in each strain gauge group of the first strain assembly (321), the second strain assembly (322), and the third strain assembly (323) are respectively disposed on the inner and outer sides of the side wall where they are located. The strain gauges in the first strain assembly (321) are electrically connected to form the first measurement circuit of the first strain measurement unit (3), the strain gauges in the second strain assembly (322) are electrically connected to form the second measurement circuit of the first strain measurement unit (3), and the strain gauges in the third strain assembly (323) are electrically connected to form the third measurement circuit of the first strain measurement unit (3); the first voltage output by the first measurement circuit, the second voltage output by the second measurement circuit, and the third voltage output by the third measurement circuit are used together to obtain the force exerted by the surgical instrument along the first direction, the second direction, and the third direction.

4. The three-dimensional force sensing mechanism at the end of the surgical robot according to claim 3, characterized in that, The sensing mechanism also includes a limiting member (4), one end of which is fixedly connected to the side of the second connecting end (2) away from the robotic arm of the surgical robot, and the other end extends to a position close to the first connecting end (1) and there is a limiting gap between it and the first connecting end (1), which is used to limit the deformation of the sensing mechanism along the third direction.

5. The three-dimensional force sensing mechanism at the end of a surgical robot according to claim 4, characterized in that, The sensing mechanism further includes a second strain measurement unit (5), the structure of which is the same as that of the first strain measurement unit (3). The second strain measurement unit (5) and the first strain measurement unit (3) are symmetrically arranged relative to the sensing mechanism along a third-direction axis. The vertical distance from the second strain measurement unit (5) to the stress concentration point of the surgical instrument is greater than the vertical distance from the first strain measurement unit (3) to the stress concentration point of the surgical instrument. The second strain measurement unit (5) is used in conjunction with the first strain measurement unit (3) to provide early warning of the depth of intervention of the surgical instrument on the operating object.

6. A method for measuring three-dimensional force at the end effector of a surgical robot, characterized in that, The method, implemented using the three-dimensional force sensing mechanism at the end of a surgical robot as described in any one of claims 1-5, comprises: S1. Collect the first voltage output by the first measurement circuit of the first strain measurement unit (3), the second voltage output by the second measurement circuit, and the third voltage output by the third measurement circuit, and generate a voltage signal matrix based on the first voltage, the second voltage, and the third voltage; S2. Input the voltage signal matrix and decoupling coefficient matrix into a linear regression model established based on the least squares method for decoupling operation to obtain a three-dimensional force matrix; the decoupling coefficient matrix is ​​obtained by performing a static calibration experiment on the sensing mechanism; S3. Based on the three-dimensional force matrix, determine the forces acting on the surgical instrument along the first direction, the second direction, and the third direction.

7. The measurement method according to claim 6, characterized in that, The method prior to step S1 further includes: S0. Based on the geometric dimensions, material property parameters, and multiple sets of test force parameters of the three-dimensional force sensing mechanism at the end of the surgical robot, perform finite element simulation to obtain the target setting positions of the first strain component (321), the second strain component (322), and the third strain component (323), and paste the first strain component (321), the second strain component (322), and the third strain component (323) to the corresponding target setting positions.

8. The measurement method according to claim 6, characterized in that, The method further includes: The first strain component (321), the second strain component (322), and the third strain component (323) of the first strain measurement unit (3) are respectively attached to the target setting positions of the first strain component (321), the second strain component (322), and the third strain component (323) of the second strain measurement unit (5) at positions symmetrical with respect to the sensing mechanism along the third direction axis.

9. The measurement method according to claim 8, characterized in that, The method further includes: While collecting the first voltage output by the first measurement circuit of the first strain measurement unit (3), the second voltage output by the second measurement circuit, and the third voltage output by the third measurement circuit, the first voltage output by the first measurement circuit of the second strain measurement unit (5), the second voltage output by the second measurement circuit, and the third voltage output by the third measurement circuit are also collected. The ratio of the first voltage, or the second voltage, or the third voltage corresponding to the first strain measurement unit (3) and the second strain measurement unit (5) is used as the intervention safety characteristic parameter; The system compares the intervention safety feature parameters with the safety threshold range and outputs corresponding warning messages based on the comparison results.

10. The measurement method according to claim 9, characterized in that, The intervention safety characteristic parameters are compared with the safety threshold range of the intervention safety characteristic parameters, and corresponding early warning information is output based on the comparison result, including: If the intervention safety feature parameter is within the safety threshold range and continues to approach the boundary value of the safety threshold range within a preset time period, then the first warning message is output. If the intervention safety feature parameter exceeds the safety threshold range and the absolute value of the difference between the parameter and the boundary value of the safety threshold range is less than the first preset threshold, then a second warning message is output. If the rate of change of the intervention safety feature parameter within a preset time is greater than a preset rate of change threshold, or if the intervention safety feature parameter exceeds the safety threshold range and the absolute value of the difference between the threshold value and the boundary value of the safety threshold range is greater than or equal to the first preset threshold, then a third warning message will be output.

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