Structural sensing fusion type shafting force measuring device and force decoupling method thereof

Abstract

The application belongs to the technical field of mechanics measurement, and discloses a structure-sensing fusion type shafting force measuring device and a force decoupling method thereof. Under the premise of not changing the original structural integrity and performance, a force measuring instrument integrated with multiple sensing units is fused into the connecting interface between shafting transmission structures to form a multi-dimensional force measuring device with deep fusion of transmission structures and sensing units, so that force component information of each connecting interface of the shafting under different load conditions can be accurately obtained, and accurate multi-dimensional force measurement can be realized. The force decoupling method for the structure-sensing fusion type shafting force measuring device is also provided, which is based on the force flow transmission law, constructs the correlation between the force / torque applied by the outside and the force / torque sensed by each sensing unit of the force measuring instrument, and realizes accurate decoupling of force / torque in each direction in combination with key parameters of the transmission structure and the sensing unit. The method is simple and has strong universality, and provides an important research foundation for subsequent high-precision multi-dimensional force measurement of the ship propulsion shafting, force flow transmission error analysis and acoustic performance evaluation.

Description

Technical Field

[0001] This invention belongs to the field of mechanical measurement technology and relates to a structural sensing fusion shaft system force measuring device and its force decoupling method. Background Technology

[0002] As the core transmission component of a ship's propulsion system, the shafting plays a crucial role in transmitting main engine power to the propeller. Its stable and reliable operation directly determines the strategic level and service life of high-end equipment such as large UUVs and surface ships. During operation, the shafting system simultaneously bears multidimensional static forces caused by its own weight, hydrostatic pressure, and hull deformation, as well as multidimensional dynamic forces caused by wave excitation, main engine excitation, and structural coupled vibration. Accurately measuring the multidimensional static / dynamic composite forces of the shafting system under different operating conditions is a core prerequisite for conducting research on ship propulsion system condition monitoring and acoustic stealth performance evaluation. However, existing force measurement technologies mostly employ direct measurement schemes such as series sensors, or indirect measurement schemes such as inverting forces using parameters such as strain and vibration. These methods are prone to altering the integrity of the transmission structure, making it difficult to accurately obtain force information under static / dynamic force coupling. Furthermore, they cannot accurately invert the global force state of the shafting system using the captured local force information. They generally suffer from low measurement accuracy, high decoupling difficulty, and poor adaptability to actual ship operating conditions. Therefore, there is an urgent need to develop a structural sensing fusion shafting force measurement device and its force decoupling method to provide important technical support for the accurate measurement of multidimensional static / dynamic composite forces and the evaluation of shafting acoustic performance.

[0003] Regarding a structural sensing-integrated shaft system force measurement device and its force decoupling method, Hou Xiaojuan, He Jian, et al. proposed a multi-dimensional force measurement device combining strain gauges and piezoelectric crystals in their patent "A Multi-dimensional Force Measurement Device that Combines Static and Dynamic Measurement" (CN 119509749 B). This device combines static and dynamic force signal measurement with high accuracy. However, the measurement accuracy of this sensor is also affected by the installation state, and the compatibility between the multi-dimensional force sensor and the measured structure under real operating conditions is not considered. Furthermore, the cantilever beam structure has weak load-bearing capacity, limiting its application. Regarding force decoupling methods for shaft system force measurement devices, Cai Jiale of Dalian University of Technology, in his 2024 paper "Multi-dimensional Force Decoupling of Piezoelectric Turning Force Gauge Based on HSA-SVR," used a nonlinear decoupling algorithm to reduce inter-directional interference of the piezoelectric multi-dimensional force gauge to ensure measurement accuracy. However, during parameter optimization, the contribution of the measured structure parameters to the inter-directional interference of the force gauge was not considered. Therefore, it is essential to provide a structural sensing-integrated shaft system force measurement device and its force decoupling method. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention presents a structural sensing fusion-based shafting force measurement device and its force decoupling method. The aim is to integrate a shaft segment force gauge with multiple sensing units and a base force gauge into the shafting transmission structure without altering the original structural integrity and transmission performance. This forms a system-level multidimensional force measurement device with deep integration of the transmission structure and sensing units, enabling precise acquisition of force component information between the transmission structures under different load conditions and achieving accurate multidimensional force measurement. The proposed force decoupling method for the structural sensing fusion-based shafting force measurement device is based on the law of force flow transmission. It constructs a correlation between the externally applied force / torque and the force / torque sensed by each sensing unit of the force gauge. By combining key parameters of the transmission structure and sensing units, it achieves decoupling of forces / torques in all directions. This method has theoretical guiding significance for the multidimensional force measurement of ship propulsion shafting and the accurate decoupling of multidimensional forces between the transmission structure and the shafting.

[0005] The technical solution of the present invention: A structural sensing fusion shafting force measuring device is disclosed. First, the sliding bearing housing 4, the base force gauge 3, and the force measuring device base 8 are connected by fasteners, and the stern shaft 2, the shaft section force gauge 5, and the intermediate shaft 6 are also connected by fasteners. Second, without compromising the original transmission structure's strength, stiffness, and other key performance characteristics, the base force gauge 3 and the shaft section force gauge 5, equipped with several sensing units, are embedded between the shafting transmission structure to form a shafting multi-dimensional force measuring device that integrates the transmission structure and sensing units. Finally, a load is applied at the calibration block 1, and the force flow is transmitted to the working surfaces of the base force gauge 3 and the shaft section force gauge 5 and captured by the sensing units with force flow sensing function to obtain the multi-dimensional force components between the transmission structures, thereby achieving accurate measurement and decoupling of multi-dimensional forces in the ship's shafting.

[0006] A structural sensing fusion shaft force measuring device includes a calibration block 1, a stern shaft 2, a base force measuring instrument 3, a sliding bearing seat 4, a shaft segment force measuring instrument 5, an intermediate shaft 6, a fixed end 7, and a force measuring device base 8; The lower surface of the force measuring device base 8 is fixed to the ground, and the upper surface is fixed with the base force measuring instrument 3 and the fixed end 7; one side of the intermediate shaft 6 is connected to the fixed end 7, and the other side is connected to the lower plate of the shaft section force measuring instrument 5; the flange part of the stern shaft 2 is connected to the upper plate of the shaft section force measuring instrument 5, and the optical shaft part is engaged with the bearing bush of the sliding bearing seat 4 to form a sliding friction pair; the sliding bearing seat 4, which provides radial support, is fixed to the upper plate of the base force measuring instrument 3; when the calibration block 1 located on the end face of the stern shaft 2 bears multidimensional loads, part of the force flow is transmitted to the shaft section force measuring instrument 5 through the stern shaft 2, and another part of the force flow is transmitted to the sliding bearing seat 4 through the stern shaft 2, and then to the base force measuring instrument 3; the force flow components are captured by the sensing units inside the base force measuring instrument 3 and the shaft section force measuring instrument 5.

[0007] A force decoupling method for a structure-sensing fusion shaft force measuring device includes the following steps: The first step is to simplify the structural sensing fusion shaft force measurement device into an extended beam; The stern shaft 2, shaft segment force gauge 5, and intermediate shaft 6 are rigidly connected by fasteners. The intermediate shaft 6 is fixed to the fixed end 7, and its degrees of freedom in all directions are restricted. The base force gauge 3 forms a sliding friction pair with the stern shaft 2, providing radial support for the stern shaft 2. According to the force characteristics of the structural sensing fusion shaft system force measuring device, the stern shaft 2, shaft segment force gauge 5, and intermediate shaft 6 are equivalent to a beam with one end fixed and the other end free. The sliding bearing seat 4 is equivalent to a movable hinge support, and the fixed end 7 is equivalent to a fixed support. The beam, movable hinge support, and fixed support are combined to form an extended beam. When the calibration block 1 bears a load, the extended beam is simultaneously subjected to shear force and bending moment. The structural sensing fusion shaft system force measuring device is subjected to a combination of force and moment. The force and moment dimensions measured by the structural sensing fusion shaft system force measuring device are also different depending on the direction, magnitude, and method of load application. The second step is to solve for the multidimensional force components transmitted to the base force gauge 3 and the shaft force gauge 5. Total weight of the extended beam G Shaft diameter d Total length L Uniformly distributed load caused by its own weight q = G / L The geometric center of calibration block 1 is defined as free point A; the geometric center of the upper plate of the base force gauge 3 is defined as support point B; the geometric center of the contact surface between the fixed end 7 and the intermediate shaft 6 after fixation is defined as fixed point C; and the geometric center of the upper plate of the shaft segment force gauge 5 is defined as calculation point D. The length of segment AB is... L 1. Section BD L 2. DC segment length L 3; Apply a vertically downward static force at free point A. F From the force and torque equilibrium equation, we get: (1) in, F B This represents the support reaction force provided by free point B; F C This represents the support reaction force provided by fixed point C; M C This represents the bending moment provided by fixed point C; The extended beam is a statically indeterminate structure of one degree, requiring the introduction of deformation compatibility equations. Since the deflection at support point B is zero, we obtain: (2) in, δB ( F ) represents the force. F Deflection caused at support point B; δB ( q ) represents a uniformly distributed loadq Deflection caused at support point B; δB ( F B () indicates the support reaction force provided by support point B. F B The deflection caused at support point B is expressed as follows: (3) in, E This represents the elastic modulus of the beam material. I The moment of inertia of the beam's cross section; Further, the support reaction force provided by support point B is obtained. F B The expression is: (4) Calculate the force at point D F D With torque M D The expression is: (5) The third step is to decouple the force state of the shaft section force gauge 5; The shaft segment force gauge 5 contains four sensing units arranged in a diamond pattern. The geometric center of each sensing unit is located at a diagonal of 2. r The rhomboid vertex; the force acting on the upper plate of the shaft segment force gauge 5. Fa x , Fa y , Fa z It is jointly undertaken by 4 sensing units, and the force is decomposed into component forces of 4 sensing units. fa x , fa y , fa z The torque acting on the upper plate of the shaft section force gauge 5 Ma x , Ma y , Ma z The decomposition form is related to the size of the rhombus, and the plane containing the rhombus is 5 meters away from the upper plate of the shaft segment force gauge. h The component torque passes through fa x , fa y , fa z The force and torque decomposition follows the principles of force translation, lever principle, and average distribution principle, thus yielding the decoupling equation for shaft segment force gauge 5: (6) The subscripts 1, 2, 3, and 4 indicate the sensing unit numbers inside the shaft segment force gauge 5; Combine the calculation of the force at point D F D With torque M D The expression states that the force acting on the upper plate of the shaft segment force gauge 5 is equal to... F D ,get Fa x = F D The torque acting on the upper plate of the shaft section force gauge 5 is equal to M D ,get Ma y = M D The force and torque in all other directions are zero. Fa y = Fa z = Ma x = Ma z =0.

[0008] Step 4: Decouple the force state of the base force gauge 3; The base force gauge 3 contains four sensing units arranged in a rectangular pattern, with the geometric center of each sensing unit being the longest axis. a ,Width b The rectangular vertex; the force acting on the upper plate of the base force gauge 3. Fb x , Fb y , Fb z It is jointly undertaken by 4 sensing units, and decomposed into the component force measured by the 4 sensing units. fb x , fb y , fb z The torque acting on the upper plate of the base force gauge 3 Mb x , Mb y , Mb z The decomposition form is related to the size of the rectangle, and the plane containing the rectangle is 3 meters away from the upper plate of the base force gauge. c The component torque passes through fb x , fb y , fbz The force and torque decomposition follows the principles of force translation, lever principle, and average distribution principle, thus yielding the decoupling equation of the base force gauge 3: (7) Among them, the subscripts 5, 6, 7, and 8 represent the sensing unit numbers inside the base force gauge 3; Combined with the support reaction force provided by support point B F B The expression states that the force acting on the upper plate of the base force gauge 3 is numerically equal to the support reaction force provided by support point B. F B The two directions are opposite, resulting in Fb x =- F B Since the deflection at support point B is 0, we obtain... Mb y = M B =0; because the base force gauge 3 cannot sense the internal stress change of the stern shaft 2, it obtains Fb y = Fb z = Mb x = Mb z =0.

[0009] Furthermore, the sensing units installed on the shaft segment force gauge 5 and the base force gauge 3 are composed of two types of cut quartz crystals arranged in a specific pattern. By utilizing the tensile and compressive effects and shear effects of piezoelectric crystals, static and dynamic forces are measured simultaneously, and the three-dimensional component forces are finally output. The layout of the sensing units corresponds to the forces and force rectangles experienced by the shaft segment force gauge 5 and the base force gauge 3.

[0010] Furthermore, in addition to applying a vertically downward static force to calibration block 1, the static forces and static moments in other dimensions are also decoupled in the same way, including the static force along the horizontal direction, the static force and static moment along the axial direction; the static force and static moment are applied individually or in combination; the static force is replaced with a dynamic force, or the static force and dynamic force are applied in combination. The above methods are also applicable. Force information is obtained through the shaft segment force gauge 5 and the base force gauge 3 to achieve decoupling of multidimensional static force and dynamic force and complete the multidimensional force measurement task.

[0011] The beneficial effects of this invention are as follows: It proposes a structural sensing fusion shafting force measurement device. Without compromising the original structural strength and stiffness, a force measuring instrument with sensing capabilities is embedded in the transmission shafting, creating a fusion shafting multi-dimensional force measurement device that integrates the transmission structure and sensing units. This facilitates the study of force flow transmission laws and force decoupling analysis at the system level, providing key technical support for high-precision multi-dimensional force measurement in ship propulsion shafting. Simultaneously, it proposes a force decoupling method for the structural sensing fusion shafting force measurement device. Based on the force flow transmission laws, it constructs the correlation between externally applied forces / torques and the forces / torques sensed by each sensing unit of the force measuring instrument. By combining key parameters of the transmission structure and sensing units, it achieves decoupling of forces / torques in all directions. This provides theoretical guidance for the accurate decoupling of multi-dimensional forces between ship propulsion shafting and the transmission structure. Attached Figure Description

[0012] Figure 1 This is a flowchart of a force decoupling method for a shaft system force measuring device; Figure 2 This is a schematic diagram of a structural sensing fusion shaft system force measuring device. Figure 3 This is a simplified structural diagram of a shaft system force measuring device; Figure 4 This is a schematic diagram of the sensor unit distribution of a shaft segment force gauge. Figure 5 This is a schematic diagram of the sensor unit distribution of a base force gauge; In the figure, 1-calibration block, 2-stern shaft, 3-base force gauge, 4-sliding bearing seat, 5-shaft section force gauge, 6-intermediate shaft, 7-fixed end, 8-force measuring device base. Detailed Implementation

[0013] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0014] Example The selected stern shaft 2, shaft section force gauge 5, and intermediate shaft 6 shaft diameter d =220mm, total length L =1250mm, total weight G =3500N, AB segment L 1=600mm, BD segment L 2=200mm, CD segment L 3 = 450mm; Vertical downward load applied at free point A F =5000N; Spacing between sensing units in shaft section force gauge 5 r =110mm, h =50mm; Spacing between sensing units in base force gauge 3 a =150mm,b =250mm, c =60mm; The installation steps of a structure-sensing fusion shaft force measuring device are as follows: To fix the force measuring device base 8, first use four M30×80 hex bolts to secure the base force measuring instrument 3 to the force measuring device base 8. Then, use six M20×45 socket head cap screws and four... A 20×55 internally threaded cylindrical pin mounts the fixed end 7 onto the force measuring device base 8; the intermediate shaft 6 is connected to the fixed end 7 by eight M20×70 socket head cap screws, and to the shaft section force measuring instrument 5 by eight M20×90 reamed bolts and eight M20 nuts; the sliding bearing seat 4 is connected to the base force measuring instrument 3 by four M30×80 external hex bolts and two… A 20×80 internally threaded cylindrical pin is used for fixing, and it is connected to the stern shaft 2 via a smooth shaft fit; the shaft section force gauge 5 is connected to the stern shaft 2 via eight M20×90 reamed bolts and eight M20 nuts; at this point, a structural sensing fusion shaft system force measuring device is installed, as follows. Figure 2 As shown.

[0015] A force decoupling method for a structure-sensing fusion shaft system force measurement device, such as Figure 1 As shown, the specific steps are as follows: The first step is to simplify the structural sensing fusion shaft force measurement device into an extended beam; The stern shaft 2, shaft segment force gauge 5, and intermediate shaft 6 are equivalent to a beam with one end fixed and the other end free, used to bear shear force and bending moment; the sliding bearing seat 4 is equivalent to a movable hinge support, releasing only the axial displacement degree of freedom and providing support reaction force; the fixed end 7 is equivalent to a fixed support, constraining all degrees of freedom and providing shear force and bending moment; the simplified extended beam structure is as follows: Figure 3 As shown; when calibration block 1 is subjected to a single or combined load, the extension beam will be subjected to shear force and bending moment in different directions at the same time. That is, the structural sensing fusion shaft system force measuring device is subjected to the combined action of force and moment in different directions. The force and moment measured by the structural sensing fusion shaft system force measuring device under the combined load can be obtained by vector superposition based on the force and moment calculation results under the single load. The second step is to solve for the multidimensional force components transmitted to the base force gauge 3 and the shaft force gauge 5. The support reaction force provided by support point B can be obtained from equation (4). F B =14488.81N; The force at calculation point D is obtained from equation (5). F D =12248.81N, calculate the torque on point D. M D =-1502.24 N·m; The third step is to decouple the force state of the shaft section force gauge 5; The sensor units of the shaft segment force gauge 5 are distributed as follows: Figure 4 As shown; the component forces measured by each sensing unit of the shaft segment force measuring instrument 5 are obtained from equation (6). fa x1 =3062.20N, fa y1 =0N, fa z1 =-9612.19N, fa x2 =3062.20N, fa y2 =0N, fa z2 =0N, fa x3 =3062.20N, fa y3 =0N, fa z3 =9612.19N, fa x4 =3062.20N, fa y4 =0N, fa z4 =0N; Step 4: Decouple the force state of the base force gauge 3; The sensor units of the base force gauge 3 are distributed as follows: Figure 5 As shown; the component forces measured by each sensing unit of the base force gauge 3 are obtained from equation (7). fb x5 =3622.20N, fa y5 =0N, fa z5 =0N, fb x6 =3622.20N, fa y6 =0N, fa z6 =0N, fb x7 =3622.20N, fa y7 =0N, fa z7 =0N, fb x8 =3622.20N, fa y8 =0N, fa z8 =0N; Based on the law of force flow transmission, this method simplifies the shafting force measuring device into an extended beam structure, constructs a mapping model of the correlation between the externally applied force / torque and the force / torque sensed by each sensing unit of the force measuring instrument, and combines the key parameters of the transmission structure and sensing units to accurately decouple the forces / torques transmitted to each force measuring instrument in all directions. The method is simple and highly versatile, providing an important research foundation for subsequent high-precision measurement of multidimensional forces in ship propulsion shafting, error analysis of force flow transmission, and acoustic performance evaluation.

Claims

1. A structural sensing fusion shaft system force measuring device, characterized in that, The structure-sensor fusion shaft force measuring device includes a calibration block (1), a stern shaft (2), a base force measuring instrument (3), a sliding bearing seat (4), a shaft section force measuring instrument (5), an intermediate shaft (6), a fixed end (7), and a force measuring device base (8). The lower surface of the force measuring device base (8) is fixed on the ground, and the upper surface is fixed with the base force measuring instrument (3) and the fixed end (7); one side of the intermediate shaft (6) is connected to the fixed end (7), and the other side is connected to the lower plate of the shaft section force measuring instrument (5); the flange part of the stern shaft (2) is connected to the upper plate of the shaft section force measuring instrument (5), and the optical shaft part is engaged with the bearing bush of the sliding bearing seat (4) to form a sliding friction pair; the sliding bearing seat (4) that provides radial support is fixed to the upper plate of the base force measuring instrument (3); when the calibration block (1) located on the end face of the stern shaft (2) bears multidimensional load, part of the force flow is transmitted through the stern shaft (2) to the shaft section force measuring instrument (5), and another part of the force flow is transmitted through the stern shaft (2) to the sliding bearing seat (4), and then to the base force measuring instrument (3); the force flow component is captured by the sensing unit inside the base force measuring instrument (3) and the shaft section force measuring instrument (5).

2. A force decoupling method for the structural sensing fusion shaft system force measuring device as described in claim 1, characterized in that, The steps are as follows: The first step is to simplify the structural sensing fusion shaft force measurement device into an extended beam; The stern shaft (2), the shaft segment force gauge (5), and the intermediate shaft (6) are rigidly connected by fasteners. The intermediate shaft (6) is fixed on the fixed end (7), and its degrees of freedom in each direction are restricted. The base force gauge (3) and the stern shaft (2) form a sliding friction pair, providing radial support for the stern shaft (2). According to the force characteristics of the structural sensing fusion shaft system force measuring device, the stern shaft (2), the shaft segment force gauge (5), and the intermediate shaft (6) are equivalent to a beam with one end fixed and the other end free. The sliding bearing seat (4) is equivalent to a movable hinge support, and the fixed end (7) is equivalent to a fixed support. The beam, the movable hinge support, and the fixed support are combined to form an extended beam. When the calibration block (1) bears a load, the extended beam is simultaneously subjected to shear force and bending moment. The structural sensing fusion shaft system force measuring device is subjected to a combination of force and moment. The force and torque dimensions measured by the structural sensing fusion shaft force measuring device will also differ depending on the direction, magnitude, and method of load application. The second step is to solve for the multidimensional force components transmitted to the base force gauge (3) and the shaft force gauge (5); The third step is to decouple the force state of the shaft section force gauge (5); Step 4: Decouple the force state of the base force gauge (3).

3. The force decoupling method of the structural sensing fusion shaft system force measuring device according to claim 2, characterized in that, The specific implementation process of the second step is as follows: Total weight of the extended beam G Shaft diameter d Total length L Uniformly distributed load caused by its own weight q = G / L The geometric center of the calibration block (1) is defined as free point A, the geometric center of the upper plate of the base force gauge (3) is the support point B, the geometric center of the contact surface between the fixed end (7) and the intermediate shaft (6) after fixing is defined as fixed point C, and the geometric center of the upper plate of the shaft segment force gauge (5) is the calculation point D. The length of segment AB is defined as follows. L 1. Section BD L 2. DC segment length L 3; Apply a vertically downward static force at free point A. F From the force and torque equilibrium equation, we get: in, F B This represents the support reaction force provided by free point B; F C This represents the support reaction force provided by fixed point C; M C This represents the bending moment provided by fixed point C; The extended beam is a statically indeterminate structure of one degree, requiring the introduction of deformation compatibility equations. Since the deflection at support point B is zero, we obtain: in, δB ( F ) represents the force. F Deflection caused at support point B; δB ( q ) represents a uniformly distributed load q Deflection caused at support point B; δB ( F B () indicates the support reaction force provided by support point B. F B The deflection caused at support point B is expressed as follows: in, E This represents the elastic modulus of the beam material. I The moment of inertia of the beam's cross section; Further, the support reaction force provided by support point B is obtained. F B The expression is: Calculate the force at point D F D With torque M D The expression is: 。 4. The force decoupling method of the structural sensing fusion shaft system force measuring device according to claim 3, characterized in that, The specific implementation process of the third step is as follows: The shaft segment force gauge (5) contains four sensing units arranged in a rhombus shape. The geometric center of each sensing unit is 2 on each diagonal. r The rhomboid vertex; the force acting on the upper plate of the shaft segment force gauge (5) Fa x , Fa y , Fa z It is jointly undertaken by 4 sensing units, and the force is decomposed into component forces of 4 sensing units. fa x , fa y , fa z The torque acting on the upper plate of the shaft section force gauge (5) Ma x , Ma y , Ma z The decomposition form is related to the size of the rhombus, and the plane containing the rhombus is at a distance from the upper plate of the shaft segment force gauge (5). h The component torque passes through fa x , fa y , fa z express; Force and torque decomposition follows the principles of force translation, lever principle, and average distribution principle, thus yielding the decoupling equation of the shaft segment force gauge (5): Among them, the subscripts 1, 2, 3, and 4 represent the sensing unit numbers inside the shaft segment force gauge (5); Combine the calculation of the force at point D F D With torque M D The expression is that the force acting on the upper plate of the shaft segment force gauge (5) is equal to... F D ,get Fa x = F D The torque acting on the upper plate of the shaft section force gauge (5) is equal to M D ,get Ma y = M D The force and torque in all other directions are zero. Fa y = Fa z = Ma x = Ma z =0.

5. The force decoupling method of the structural sensing fusion shaft system force measuring device according to claim 4, characterized in that, The specific implementation process of the fourth step is as follows: The base force gauge (3) contains four sensing units arranged in a rectangular shape. The geometric center of each sensing unit is the length of the base force gauge. a ,Width b The rectangular vertex; the force acting on the upper plate of the base force gauge (3) Fb x , Fb y , Fb z It is jointly undertaken by 4 sensing units, and decomposed into the component force measured by the 4 sensing units. fb x , fb y , fb z The torque acting on the upper plate of the base force gauge (3) Mb x , Mb y , Mb z The decomposition form is related to the size of the rectangle, and the plane containing the rectangle is at a distance from the upper plate of the base force gauge (3). c The component torque passes through fb x , fb y , fb z express; Force and torque decomposition follows the principles of force translation, lever principle, and average distribution principle, thus yielding the decoupling equation of the base force gauge (3): Among them, the subscripts 5, 6, 7, and 8 represent the sensing unit numbers inside the base force gauge (3); Combined with the support reaction force provided by support point B F B The expression states that the force acting on the upper plate of the base force gauge (3) is numerically equal to the support reaction force provided by the support point B. F B The two directions are opposite, resulting in Fb x =- F B Since the deflection at support point B is 0, we obtain... Mb y = M B =0; because the base force gauge (3) cannot sense the internal stress change of the stern shaft (2), the result is... Fb y = Fb z = Mb x = Mb z =0.

6. The force decoupling method of the structural sensing fusion shaft system force measuring device according to claim 5, characterized in that, The sensing units installed on the shaft segment force gauge (5) and the base force gauge (3) are composed of two types of cut quartz crystals arranged in a way that utilizes the tension and compression effect and shear effect of piezoelectric crystals to simultaneously measure static and dynamic forces, and finally output three-dimensional component forces. The layout of the sensing units corresponds to the forces and force rectangles of the shaft segment force gauge (5) and the base force gauge (3).

7. The force decoupling method of the structural sensing fusion shaft system force measuring device according to claim 6, characterized in that, In addition to applying a vertically downward static force to the calibration block (1), the static forces and static moments in other dimensions are also decoupled in the same way, including the static force along the horizontal direction, the static force and static moment along the axial direction; Static force and static torque can be applied individually or in combination; static force can be replaced with dynamic force, or static force and dynamic force can be applied in combination. The above methods are also applicable. Force information is obtained through the shaft segment force gauge (5) and the base force gauge (3) to achieve decoupling of multidimensional static force and dynamic force and complete the multidimensional force measurement task.

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