Three-dimensional force measurement method for hydraulic support roof beam and shield beam connecting pin hole

Abstract

This invention relates to the field of stress monitoring technology for mining equipment, and discloses a method for measuring the three-dimensional stress on the connecting pin hole of a hydraulic support top beam and a shield beam. The method includes: the shield beam transferring the working load to the force axis of a three-dimensional pin sensor under load, forming a three-dimensional composite load; this load acts on the sensor, generating three-dimensional spatial deformation in the through-hole in the vertical direction, the through-hole in the horizontal direction, and the thin-walled region of the axial fixed shaft; strain gauges arranged in each region change resistance with the deformation, converting it into an analog resistance change signal; a Wheatstone bridge circuit receives this signal, utilizes the orthogonal deformation characteristics of the through-hole and the adjacent arm connection logic of the full bridge to eliminate cross-interference errors, and outputs a decoupled bridge voltage signal; this signal is substituted into the stress calculation logic to calculate and output the separated radial load in the vertical direction, the radial load in the horizontal direction, and the axial load components. This invention ensures the structural strength of the pin and achieves accurate decoupling and independent measurement of multi-component loads.

Description

Technical Field

[0001] This invention relates to the field of stress monitoring technology for mining equipment, specifically a three-dimensional stress measurement method for the connecting pin hole between the hydraulic support top beam and the shield beam. Background Technology

[0002] Hydraulic supports are essential safety support equipment in coal mining faces. In the overall structure of a hydraulic support, the top beam and the shield beam are typically hinged together using pins. During actual underground mining operations, this hinged connection bears multi-directional and multi-component external loads due to the movement of the surrounding rock and changes in the working posture of the support. To ensure safe mining operations, it is necessary to monitor the stress state of key hinge points on the hydraulic support.

[0003] Currently, existing pin bearing force measurement methods typically involve directly slotting the pin bearing surface at the stress location and attaching a resistance strain gauge. When an external load is applied to the pin bearing, causing mechanical deformation, the resistance of the strain gauge changes accordingly. The system measures this resistance change using a Wheatstone bridge and converts it into a voltage signal, thereby calculating the magnitude of the load on the pin bearing. Existing methods also utilize blind holes at the locations of radial forces on the pin bearing to measure the radial force and its planar direction.

[0004] However, the above measurement scheme has the following drawbacks in practical applications. Directly slotting or drilling holes on the surface of the core shear stress area of ​​the pin destroys the physical integrity of the core area of ​​the stress-bearing shaft, resulting in a reduction in the average diameter of the pin at the stress location. This material removal leads to a decrease in the overall strength of the pin, making it difficult to guarantee the fatigue life required under heavy-load conditions in coal mines.

[0005] Furthermore, slotting at the core shear force generation point reduces the effective contact area between the outer surface of the pin and the connecting pin hole. This reduced contact area leads to a looser fit between the pin and the hinge hole, altering the original contact stress distribution. This uneven force distribution caused by the change in local fit introduces mechanical transmission errors, preventing the sensor from objectively receiving the actual transmitted working load and reducing the accuracy of mechanical measurements.

[0006] Furthermore, in the downhole environment, hydraulic supports are subjected not only to shear and bending forces in various directions, but also to axial loads due to the overall tilting posture of the equipment. Existing strain gauge arrangements and force measurement logic can only obtain the magnitude of radial force or directional information within a single plane, lacking a measurement mechanism for multi-directional force characteristics. Their structure cannot simultaneously extract multi-dimensional deformation signals and eliminate cross-interference between loads, nor can it independently calculate the radial load components in the vertical direction, the horizontal radial load components, and the axial load components, making it difficult to reflect the true three-dimensional stress state of the hydraulic support hinge points under actual working conditions. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a method for measuring the three-dimensional force on the connecting pin hole of the hydraulic support top beam and the shield beam, which solves the problem that existing measurement methods cannot achieve decoupled measurement of the three-dimensional force at the hinge point without damaging the core strength of the pin.

[0008] To achieve the above objectives, the present invention provides a method for measuring the three-dimensional force on the connecting pin hole between the hydraulic support top beam and the shield beam, comprising the following steps: Under load conditions, the shield beam transmits the actual working load to the force axis of the three-dimensional pin sensor, forming a three-dimensional composite load at the force axis. The three-dimensional composite load acts on the three-dimensional pin sensor to produce physical deformation, and generates three-dimensional spatial deformation in the through hole in the vertical direction, the through hole in the horizontal direction, and the thin-walled area of ​​the axial fixed shaft. The second strain gauge, the third strain gauge, and the first strain gauge arranged in each region change resistance with the three-dimensional spatial deformation, converting mechanical deformation into analog resistance change signals. The Wheatstone bridge circuit receives the analog resistance change signal, uses the orthogonal deformation characteristics of the through-hole structure and the adjacent arm connection logic of the full-bridge circuit to eliminate cross interference error, and outputs the decoupled bridge voltage signal. Based on the bridge voltage signals output by each independent bridge, the force calculation logic is substituted to calculate and output the separate radial load components in the vertical direction, the radial load components in the horizontal direction, and the axial load components, thus completing the independent measurement of the three-dimensional force on the connecting pin hole of the hydraulic support top beam and the shield beam.

[0009] Preferably, forming a three-dimensional composite load at the force-bearing axis specifically includes: The shield beam applies the actual working load to the three-dimensional pin sensor under load conditions; The actual working load transmitted to the force-bearing axis is decomposed into mutually orthogonal radial load components in the plumb direction and radial load components in the horizontal direction, as well as axial load components generated by the tilt of the device. The radial load component in the plumb direction, the radial load component in the horizontal direction, and the axial load component together constitute the three-dimensional composite load at the force-bearing axis.

[0010] Preferably, the generation of three-dimensional spatial deformations in the through holes in the vertical direction, the through holes in the horizontal direction, and the thin-walled regions of the axial fixed shaft specifically includes: The radial load component in the plumb direction and the radial load component in the horizontal direction of the three-dimensional composite load act on the plumb direction through hole and the horizontal through hole of the three-dimensional pin sensor to produce orthogonal composite deformation. The orthogonal composite deformation generates the three-dimensional spatial deformation on the corresponding hole wall surface; The axial load component in the three-dimensional composite load acts on the thin-walled region of the axial fixed shaft of the three-dimensional pin sensor, causing elastic deformation. The elastic deformation generates locally amplified axial tensile and compressive deformation in the three-dimensional space.

[0011] Preferably, converting mechanical deformation into an analog resistance change signal specifically includes: The second strain gauge and the third strain gauge are synchronously biased in resistance according to the three-dimensional spatial deformation generated on the corresponding hole wall surface; The resistor bias is correspondingly converted and output as the analog resistance change signal; The resistance bias occurs synchronously with the three-dimensional spatial deformation generated by the internal stress region after bearing the load; The resistor bias is correspondingly converted and output as the analog resistance change signal; The second strain gauge arranged in the through-hole area in the vertical direction is specifically subdivided into the fifth strain gauge and the sixth strain gauge, and the third strain gauge arranged in the through-hole area in the horizontal direction is specifically subdivided into the seventh strain gauge and the eighth strain gauge. The end structure of the axially fixed shaft is divided into an outer fixed shaft, a thin-walled strain region at the stepped transition, and an inner internal stress region. The first strain gauge arranged in the thin-walled strain region corresponds to eight independent fourth strain gauges.

[0012] Preferably, the radial measurement step of outputting the decoupled bridge voltage signal specifically includes: The half-bridge measurement loop in the Wheatstone bridge circuit receives the analog resistance change signal corresponding to the via region. Based on the simulated resistance change signal, the orthogonal deformation characteristics of the through-hole structure are used to identify the small vertical hammer-shaped interference strain or the small horizontal crosstalk strain acting in the same direction as the cross interference error. The cross-interference errors are mutually canceled to achieve error elimination; After the error elimination is completed, the output voltage of the through-hole bridge in the plumb direction and the output voltage of the through-hole bridge in the horizontal direction are extracted as the bridge voltage signal after radial decoupling.

[0013] Preferably, the axial measurement step of outputting the decoupled bridge voltage signal specifically includes: The Wheatstone bridge circuit is connected to an independent bridge arm to receive the analog resistance change signal corresponding to the axial region. Based on the simulated resistance change signal, the non-axial interference deformation caused by the additional bending moment is identified as cross interference error using the adjacent arm connection logic of the full-bridge circuit. The cross-interference error is suppressed and eliminated; After the error elimination is completed, the output voltage of the axial force measurement bridge, which amplifies the axial principal strain signal, is extracted as the bridge voltage signal after axial decoupling.

[0014] Preferably, the radial step of calculating and outputting the separated radial load components in the plumb direction, the horizontal radial load component, and the axial load component specifically includes: The system analyzes the bridge voltage signal to extract the output voltage of the through-hole bridge in the plumb direction and the output voltage of the through-hole bridge in the horizontal direction; The output voltage of the through-hole bridge in the plumb direction is substituted into the horizontal radial load calculation formula in the force calculation logic to calculate the separated horizontal radial load components. The output voltage of the horizontal through-hole bridge is substituted into the formula for calculating the radial load in the plumb direction in the force calculation logic to calculate the separated radial load component in the plumb direction.

[0015] Preferably, the further comprehensive evaluation step after calculating the separated horizontal radial load component and the separated vertical radial load component specifically includes: Extract the output voltage of the aforementioned through-hole bridge in the plumb direction and the output voltage of the through-hole bridge in the horizontal direction; Substitute the output voltage of the through-hole bridge in the plumb direction and the output voltage of the through-hole bridge in the horizontal direction into the comprehensive radial composite load calculation formula to evaluate and obtain the overall force amplitude. Substitute the output voltage of the horizontal through-hole bridge and the output voltage of the vertical through-hole bridge into the formula for calculating the radial load force direction angle, and combine the abnormal working condition alignment and boundary processing logic to determine the resultant force angle. The comprehensive evaluation closed loop of the horizontal radial load component and the vertical radial load component is perfected by combining the overall force amplitude and the resultant force angle. The minimum threshold involved is determined by the root mean square of the sensor background white noise amplitude and the environmental electromagnetic interference during factory calibration.

[0016] Preferably, the axial step of calculating and outputting the separated radial load component in the plumb direction, the radial load component in the horizontal direction, and the axial load component specifically includes: The system analyzes the bridge voltage signal to extract the output voltage of the axial force measurement bridge; Substitute the output voltage of the axial force measurement bridge into the axial force calculation formula in the force calculation logic for calculation; The closed-loop measurement is completed through the calculation, and the separated axial load components are output.

[0017] Preferably, the measurement method is based on an assembly architecture, which includes: The inner and outer double-sided ear plates of the top beam are used to fix the position of the three-dimensional pin sensor, and the shield beam is used to apply the actual working load to the three-dimensional pin sensor. The three-dimensional pin sensor comprises, in sequence along the axial direction, an axial fixed shaft, a first fixed shaft component, a through hole in the plumb direction, a force-bearing shaft, a through hole in the horizontal direction, and a second fixed shaft component; The first fixed shaft component is installed in the pin hole of the outer ear plate of the top beam, and the second fixed shaft component is installed in the pin hole of the inner ear plate of the top beam. The force-bearing shaft is located between the first fixed shaft component and the second fixed shaft component; The pin hole of the shield beam is directly fitted onto the outside of the force-bearing shaft of the three-dimensional pin sensor, and the entire three-dimensional pin sensor is axially fixed by the end axial fixing shaft and nut, forming the overall measurement architecture for performing the measurement method.

[0018] This invention provides a method for measuring the three-dimensional force on the connecting pin hole between the top beam and the shield beam of a hydraulic support. It has the following advantages: 1. This invention replaces the machining method of directly slotting the surface of the core shear stress area by setting vertical and horizontal through holes in the non-core stress areas on both sides of the force-bearing shaft. This hole arrangement maintains the physical integrity of the core area of ​​the force-bearing shaft, avoids the strength reduction problem caused by the reduction of the average diameter of the pin, and ensures the overall fatigue life under heavy load conditions.

[0019] 2. This invention maintains the integrity of the contact surface between the outer surface of the load-bearing shaft and the pin hole of the shield beam. This structure prevents the pin and connecting hole from loosening due to local slotting, avoids changes in contact stress distribution caused by reduced contact surface, thereby eliminating mechanical transmission errors introduced by uneven local stress and ensuring the objectivity of actual working load transmission.

[0020] 3. This invention utilizes the spatially orthogonally distributed thin-walled regions of through holes and the stepped transition regions of the axially fixed shaft to collaboratively extract deformation, and, in conjunction with the Wheatstone bridge configuration and orthogonal deformation characteristics, eliminates cross-interference errors. This measurement logic can simultaneously extract and independently calculate the radial load components in the plumb direction, the radial load components in the horizontal direction, and the axial load components, accurately separating multi-component coupled loads and objectively reflecting the true three-dimensional stress state of the hydraulic support hinge point. Attached Figure Description

[0021] Figure 1 This is a diagram showing the positional relationship between the hydraulic support top beam, shield beam, and connecting pin shaft according to an embodiment of the present invention. Figure 2This is a three-dimensional pin sensor installation diagram at the connection hole between the top beam and the shield beam according to an embodiment of the present invention; Figure 3 This is a structural diagram of a three-dimensional pin-axis sensor according to an embodiment of the present invention; Figure 4 This is a simplified two-dimensional planar mechanical diagram of a three-dimensional pin-axis sensor according to an embodiment of the present invention; Figure 5 This is a three-dimensional solid force distribution diagram of a three-dimensional pin sensor according to an embodiment of the present invention; Figure 6 This is a partial force diagram of a three-dimensional pin-axis sensor for horizontal load measurement according to an embodiment of the present invention; Figure 7 This is a partial force diagram of a three-dimensional pin-axis sensor for measuring load in the plumb direction according to an embodiment of the present invention; Figure 8 This is a front view of the axial force strain gauge arrangement of a three-dimensional pin sensor according to an embodiment of the present invention; Figure 9 This is a cross-sectional transition view of the axial force strain gauge of a three-dimensional pin sensor according to an embodiment of the present invention; Figure 10 This is a reverse view of the axial force strain gauge arrangement of a three-dimensional pin-type sensor according to an embodiment of the present invention; Figure 11 This is a connection bridge diagram for axial force measurement of a three-dimensional pin sensor according to an embodiment of the present invention; Figure 12 This is a flowchart of a method for measuring the three-dimensional force on the connecting pin hole of a hydraulic support top beam and a shield beam according to an embodiment of the present invention.

[0022] Among them, 1. Top beam; 2. Three-dimensional pin sensor; 3. Protective beam; 201. Axial fixed shaft; 201-1. External fixed shaft; 201-2. Thin-walled strain region; 201-3. Internal stress region; 201-4. Fourth strain gauge; 202. First strain gauge; 203. First fixed shaft component; 204. Through hole in the direction of plumb bob; 205. Second strain gauge; 205-1. Fifth strain gauge; 205-2. Sixth strain gauge; 206. Stress shaft; 207. Horizontal through hole; 208. Third strain gauge; 208-1. Seventh strain gauge; 208-2. Eighth strain gauge; 209. Second fixed shaft component; 2010. Nut. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] See attached document Figure 1 To be continued Figure 3 This invention provides a method for measuring the three-dimensional force on the connecting pin hole between the top beam and the shield beam of a hydraulic support. This method is based on a specific assembly structure. The overall measurement structure includes: a top beam 1, a three-dimensional pin sensor 2, and a shield beam 3.

[0025] The top beam 1 and the shield beam 3 are mechanically connected via a pin hole located at their junction. A three-dimensional pin sensor 2 is installed at the pin hole where the top beam 1 and the shield beam 3 meet. (See attached...) Figure 1 The local cross-sectional structure corresponding to the central section line, the three-dimensional pin sensor 2 is horizontally distributed along the central axis and installed in the pin hole through the inner and outer double ear plates of the top beam 1.

[0026] The structure exhibits a centrally symmetrical, horizontally layered, nested relationship. The outer ear plates of the shield beam 3 are distributed inside the ear plates on both sides of the top beam 1. The fit is achieved by combining the top beam 1 with the shield beam 3 under load. The inner and outer ear plates of the top beam 1 are used to fix the position of the three-dimensional pin sensor 2, while the shield beam 3 applies the actual working load to the three-dimensional pin sensor 2. This fit design concentrates the shear stress area of ​​the pin in a specific shaft segment, providing a structural basis for subsequent three-dimensional load physical decomposition.

[0027] The three-dimensional pin sensor 2 features a multi-step shaft segment. Along its axial direction, the three-dimensional pin sensor 2 sequentially includes an axially fixed external shaft 201, a first fixed shaft component 203, a vertical through hole 204, a force-bearing shaft 206, a horizontal through hole 207, and a second fixed shaft component 209. One end of the three-dimensional pin sensor 2 is locked in place by a nut 2010.

[0028] The first fixed shaft component 203 is installed in the pin hole of the outer ear plate of the top beam 1. The second fixed shaft component 209 is installed in the pin hole of the inner ear plate of the top beam 1. The force-bearing shaft 206 is located between the first fixed shaft component 203 and the second fixed shaft component 209. The pin hole of the shield beam 3 is directly fitted onto the outside of the force-bearing shaft 206 of the three-dimensional pin sensor 2. The entire three-dimensional pin sensor 2 is axially fixed by the cooperation of the end axial external fixed shaft 201 and the nut 2010. Since the outer ear plate of the shield beam 3 is fixed in the internal space of the ear plates on both sides of the top beam 1, the axial position of the shield beam 3 is simultaneously limited.

[0029] The load-bearing shaft 206 is the core component that bears the radial shear force. A vertical through hole 204 is provided between the load-bearing shaft 206 and the first fixed shaft component 203. A horizontal through hole 207 is provided between the load-bearing shaft 206 and the second fixed shaft component 209. A second strain gauge 205 is arranged in the area of ​​the vertical through hole 204. A third strain gauge 208 is arranged in the area of ​​the horizontal through hole 207. A first strain gauge 202 is arranged in the strain area of ​​the axially external fixed shaft 201.

[0030] The structural design of the three-dimensional pin sensor 2 shifts the strain measurement area to the through holes on both sides of the core stress area, avoiding slotting on the core shear stress surface of the stress shaft 206. This structural distribution ensures the shear strength of the pin body while eliminating structural defects such as reduced average pin diameter and loose fit caused by slotting, thus guaranteeing the accuracy and stability of radial force measurement on both sides.

[0031] See attached document Figure 12 This invention provides a method for measuring the three-dimensional force on the connecting pin hole between the hydraulic support top beam and the shield beam, comprising the following steps: S1, the shield beam 3 transmits the actual working load to the force shaft 206 of the three-dimensional pin sensor 2 under the load condition, forming a three-dimensional composite load at the force shaft 206. S2, the three-dimensional composite load acts on the three-dimensional pin sensor 2 to produce physical deformation, and three-dimensional spatial deformation is generated in the through hole 204 in the vertical direction, the through hole 207 in the horizontal direction and the thin-walled area of ​​the axial external fixed shaft 201. S3, the second strain gauge 205, the third strain gauge 208 and the first strain gauge 202 arranged in each region change resistance with the three-dimensional spatial deformation, converting mechanical deformation into analog resistance change signal; S4, the Wheatstone bridge circuit receives the analog resistance change signal, uses the orthogonal deformation characteristics of the through-hole structure and the logic of the adjacent arm connection of the full bridge circuit to eliminate cross interference error, and outputs the decoupled bridge voltage signal. S5, based on the bridge voltage signals output by each independent bridge, substitutes them into the force calculation logic to calculate and output the separate radial load components in the vertical direction, the radial load components in the horizontal direction, and the axial load components, thus completing the independent measurement of the three-dimensional force on the connecting pin hole of the hydraulic support top beam and the shield beam.

[0032] The following section will provide a detailed explanation of each step in the three-dimensional force measurement method for the connecting pin hole between the hydraulic support top beam and the shield beam, as well as the related physical calculation decoupling process.

[0033] See attached document Figure 4 With appendix Figure 5In this embodiment, when the hydraulic support supports the roof in the underground coal mining face, its hinge area will generate complex spatial composite forces due to the downward pressure of the roof and the tilting of the device caused by the unevenness of the floor. As a preferred embodiment, this application analyzes the load transmission and physical deformation generation process through the following steps: S101, the shield beam 3 transmits the actual working load to the bearing part of the three-dimensional pin sensor 2, namely the force shaft 206, under the load condition.

[0034] S102, after the force-bearing shaft 206 bears the actual working load, a three-dimensional composite load is formed at the force-bearing shaft 206. Based on the principle of equivalent substitution of force systems in elasticity, the decomposition calculation process of spatial composite forces can be achieved by those skilled in the art using the orthogonal decomposition method of spatial rectangular coordinate system. The vector composition and decomposition theorem of forces is a well-known technology in this field and will not be elaborated here.

[0035] Combined with appendix Figure 4 The two-dimensional planar mechanical diagram and the three-dimensional solid structure distribution on the right show that the radial load applied by the shield beam 3 to the three-dimensional pin sensor 2 is decomposed into two mutually orthogonal force components, namely the radial load component in the plumb direction and the radial load component in the horizontal direction.

[0036] In the appendix Figure 4 With appendix Figure 5 In the representation of the point of application of force, the arrow of the radial load component in the vertical direction points vertically downward to the upper surface of the force-bearing shaft 206, while the arrow of the horizontal radial load component passes horizontally through the shaft center and points to the side surface of the force-bearing shaft 206. The axial load component generated by conditions such as device tilting points along the pin axis towards the left fixed shaft end face. The aforementioned radial load component in the vertical direction, the horizontal radial load component, and the axial load component together constitute a three-dimensional composite load at the force-bearing shaft 206.

[0037] Before explaining the deformation mechanism, it is important to note that the deformation response of metallic media is based on the physical property of elastic deformation of materials. When the matrix material of the three-dimensional pin sensor 2 is subjected to compression or tension within its elastic limit, the internal lattice spacing undergoes a reversible change, thereby linearly mapping the external mechanical force into a change in the local geometric dimensions of the structure. This change in macroscopic dimensions constitutes the physical reference for subsequent measurement conversion.

[0038] S201, via the aforementioned mechanical transmission path, the three-dimensional composite load acts on the three-dimensional pin sensor 2 to produce physical deformation, and corresponding three-dimensional spatial deformation is generated in the through hole 204 in the vertical direction, the through hole 207 in the horizontal direction, and the thin-walled area of ​​the axial external fixed shaft 201.

[0039] S202, regarding the deformation response mechanism of radial loads, the three-dimensional pin sensor 2 has orthogonally oriented through-hole segments machined in a solid cylindrical substrate. As the cross-sectional area of ​​the structure decreases sharply at the through-hole segments, the internal stress distribution of the substrate under stress becomes concentrated. When the vertical radial load component and the horizontal radial load component in the three-dimensional composite load are transmitted to the through-hole area through the solid metal medium, the vertical through-hole 204 and the horizontal through-hole 207 generate orthogonal composite deformations in the vertical and horizontal directions respectively, relying on the local stiffness variation characteristics of the hole structure, thereby generating three-dimensional spatial deformation on the hole wall surface. The physical basis of this deformation process lies in the deformation coupling effect of the orthogonal double through-holes, that is, the radial force in a certain direction will produce a small compressive deformation on the through-hole wall parallel to it, while inducing a relatively amplified tensile deformation difference on the through-hole wall perpendicular to it. This multi-dimensional correlation of deformation distribution provides a mechanical basis for the subsequent separation and extraction of orthogonal force signals.

[0040] S203, regarding the deformation response mechanism of axial load, the axial load component in the three-dimensional composite load acts on the end face of the three-dimensional pin sensor 2 and is internally transmitted along the central horizontal axis. To improve measurement sensitivity, a thin-walled region is machined on the axial external fixed shaft 201. This thin-walled region reduces the axial tensile and compressive section modulus of this structural segment by reducing the outer diameter of the local cylinder or the thickness of the material inside. When the axial load component is transmitted to this thin-walled region, the structure undergoes elastic deformation under stress, generating locally amplified axial tensile and compressive three-dimensional spatial deformation. This design, which staggers the stress-bearing parts and deformation-sensitive parts along the axial direction, avoids damaging the material integrity on the surface of the stress-bearing shaft 206 that bears the main shear force, ensuring the overall stiffness and service life of the three-dimensional pin sensor 2 solid structure.

[0041] See attached document Figure 8 Appendix Figure 9 With appendix Figure 10 In this embodiment, to convert the three-dimensional spatial deformation generated in the aforementioned steps into a measurable electrical signal, this application analyzes the process of strain sensing and resistance signal conversion based on the piezoresistive effect of metal strain gauges and the force measurement principle of Wheatstone bridges. Before discussing the specific circuit configuration, it should be noted that when the strain-sensitive gate material undergoes geometric deformation under stress, the relative change in its length and cross-sectional area will cause a linear shift in its resistance value. This physical response law forms the basis for mapping mechanical deformation to electrical parameters.

[0042] S301, Regarding the deformation sensing loop for radial load, the three-dimensional pin sensor 2 implements a multi-dimensional strain gauge arrangement strategy in the internal hole region. As a preferred embodiment, a second strain gauge 205 is arranged in the through-hole region 204 in the vertical direction, and a third strain gauge 208 is arranged in the through-hole region 207 in the horizontal direction. The second strain gauge 205 and the third strain gauge 208 arranged in each region are attached to the inner wall of the through-hole using industrial adhesive. As the three-dimensional spatial deformation is transmitted to the substrate, the sensitive metal mesh inside each strain gauge undergoes synchronous microscopic tensile or compressive deformation, thereby causing a regular change in its own resistance value, thus converting the pure mechanical state into a corresponding analog resistance change signal.

[0043] S302, combined with appendix Figure 8 Appendix Figure 9 With appendix Figure 10 This paper explores a deformation sensing structure for axial loads. In this embodiment, a double-sided orthogonal arrangement strategy is adopted in the thin-walled region of the axial external fixed shaft 201. The end structure of the axial external fixed shaft 201 is divided into the outer external fixed shaft 201-1, the thin-walled strain region 201-2 at the stepped transition, and the internal stress region 201-3.

[0044] The axial first strain gauge 202 mentioned in the aforementioned architecture is specifically composed of a network of eight independent fourth strain gauges 201-4 in this embodiment. On the front side of the thin-walled strain region 201-2, i.e., attached... Figure 8 At the indicated location, four fourth strain gauges 201-4 are evenly distributed circumferentially at 90-degree intervals. strain gauge strain gauge and strain gauges Similarly, on the opposite side of the thin-walled strain region 201-2, i.e., the attached... Figure 12 At the location shown, four other fourth strain gauges 201-4 are also evenly distributed circumferentially, which are strain gauges... strain gauge strain gauge and strain gauges Strain gauges distributed on the front To strain gauge Strain gauges with opposite distribution To strain gauge The thin-walled strain region 201-2 forms a geometrically symmetrical relationship.

[0045] S303, the aforementioned eight fourth strain gauges 201-4, specifically designed for measuring axial force, operate in concert. In the initial unloaded assembly state, the Wheatstone bridge circuit is in a balanced reference state, and the initial resistance values ​​of each fourth strain gauge 201-4 satisfy... When the internal stress region 201-3 bears the actual load, the thin-walled strain region 201-2 undergoes axial tensile and compressive three-dimensional spatial deformation, causing the above-mentioned eight fourth strain gauges 201-4 to synchronously undergo resistance bias, generating corresponding simulated resistance change signals.

[0046] The physical purpose of this double-sided orthogonal symmetrical strain gauge arrangement strategy (S304) is to effectively counteract the signal interference of eccentric bending moment. In complex downhole working conditions, axial force is often accompanied by eccentricity. When eccentric stress exists, the fourth strain gauge 201-4, symmetrically arranged on both sides of the same diameter, will exhibit a physical state where one side is under tension and the other side is under compression. In terms of circuit connection configuration, the strain gauges are pasted on the front side... With strain gauge Interconnected strain gauges With strain gauge They are connected in series to the two independent arms of the Wheatstone bridge circuit; strain gauges are attached to the reverse side. With strain gauge Series, strain gauge With strain gauge The two bridge arms are connected in series to the other two independent bridge arms. Through the above series connection logic, the bending moment and strain signals with opposite directions will cancel each other out, ensuring that the extracted bridge voltage signal only reflects the pure axial force characteristics.

[0047] See attached document Figure 6 Appendix Figure 7 and attached Figure 11 In this embodiment, when a three-dimensional composite load is applied to the force axis 206 of the three-dimensional pin sensor 2 and generates a three-dimensional spatial deformation, the system uses strain gauges arranged in each region to convert the mechanical deformation into an analog resistance change signal. To obtain independent load components, a Wheatstone bridge circuit receives the analog resistance change signal, utilizes the orthogonal deformation characteristics of the through-hole structure and the adjacent arm connection logic of the full-bridge circuit to eliminate cross-interference errors, and outputs a decoupled bridge voltage signal. Before detailing the calculation steps, the conversion process from resistance change to voltage signal can be implemented using a conventional Wheatstone bridge circuit by those skilled in the art. The unbalanced output theorem, which relies on subtracting the resistance changes of adjacent bridge arms and adding the resistance changes of relative bridge arms, is a well-known technique in the field and will not be elaborated upon here.

[0048] S401, combined with appendix Figure 6 The local force diagram shown illustrates the bridge decoupling connection logic for the region of the through-hole 204 in the plumb direction. The aforementioned second strain gauge 205 is specifically subdivided into a fifth strain gauge 205-1 and a sixth strain gauge 205-2. In the half-bridge measurement loop of the Wheatstone bridge circuit, the fifth strain gauge 205-1 serves as the first bridge arm resistor. The sixth strain gauge, 205-2, is used as the second bridge arm resistor. Connect, and supplement with a fixed resistor and fixed resistor Complete the circuit. Based on the physical effects of stress concentration and path deflection caused by the internal opening of the force-bearing shaft 206, when the through-hole area is subjected to radial load, the stress lines accumulate on both sides of the through-hole 204 in the vertical direction, causing the deformation in the horizontal direction of this area to be greater than the deformation in the vertical direction.

[0049] Based on the above physical phenomena, the system uses the original output voltage formula of the plumb-direction through-hole bridge to obtain the initial voltage response. The original output voltage formula of the plumb-direction through-hole bridge is as follows: ; in, This indicates the output voltage of the through-hole bridge in the direction of the plumb bob; to These represent the initial base resistances of each corresponding arm of the bridge; This represents the change in resistance of the strain gauge in the first bridge arm after it is subjected to load; This indicates the change in resistance of the strain gauge in the second bridge arm after being loaded; This represents the initial bridge power supply excitation voltage. Regarding the fractional operation logic involved in the above formulas, since... and The sum of the resistance values ​​of physically existing resistive elements is a non-zero positive real number that is far from zero under any operating condition. This physical characteristic naturally avoids the risk of computational divergence caused by the denominator approaching zero at the algorithm level, ensuring the completeness of the analytical logic.

[0050] S402, further, based on the structural symmetrical installation characteristics and the initial balance condition of the bridge... And the deformation on the top and bottom sides satisfies The system uses a simplified output voltage formula for a plumb-direction through-hole bridge for dimension reduction and decoupling. The simplified output voltage formula for the plumb-direction through-hole bridge is as follows: ; in, Indicates the excitation voltage of the bridge power supply; This indicates the sensitivity coefficient of the resistance strain gauge; This indicates the local strain of the upper strain gauge; This indicates the local strain of the lower strain gauge; This represents the combined strain generated in the horizontal direction.

[0051] As a preferred approach, the core technical objective of this simplified formula is to use the differential operation mechanism of subtracting the resistance changes of adjacent bridge arms to cancel out the interference strain of the small plumb bob acting in the same direction, thereby separating and extracting the feature signal that purely represents the horizontal force at the hardware signal level.

[0052] S403, following a similar structural measurement logic, explores the bridge decoupling connection logic in the horizontal via 207 region. (See attached diagram.) Figure 7 The local stress diagram shown illustrates that the aforementioned third strain gauge 208 is further subdivided into a seventh strain gauge 208-1 and an eighth strain gauge 208-2. The seventh strain gauge 208-1 and the eighth strain gauge 208-2 are respectively connected as strain gauges in a Wheatstone bridge. With strain gauge supplemented by fixed resistors and fixed resistor Construct a measurement circuit. Under this arrangement, the deformation in the vertical direction within the force axis 206 region becomes the dominant factor.

[0053] The system uses the output voltage formula of a horizontal through-hole bridge to separate and extract the electrical signal. The output voltage formula of the horizontal through-hole bridge is: ; in, This indicates the output voltage of the horizontal through-hole bridge; This represents the combined strain generated in the plumb direction. The technical purpose of using this formula is that, based on the differential connection architecture of adjacent arms of the half-bridge, the small crosstalk strain in the horizontal direction is subtracted and canceled out at the circuit level, ensuring the output bridge voltage signal's directional sensing capability of the principal strain in the plumb direction.

[0054] S404, Regarding the full-bridge assembly logic for axial force measurement, combined with the appendix... Figure 11 The stress variation trend and the principle of the full-bridge circuit are explained in detail. The first strain gauge 202, which is arranged in the thin-walled strain region 201-2 of the axially fixed shaft 201, is specifically subdivided into eight independent axial strain gauges and connected to four independent bridge arms in this embodiment. (See attached...) Figure 11 The arrow indicates the physical change trend of the strain gauge under axial tension. strain gauge strain gauge and strain gauges Its resistance increases positively, while the strain gauge under compression... strain gauge strain gauge and strain gauges Its resistance decreases in the opposite direction. The system uses the axial force measurement bridge output voltage formula to eliminate global eccentricity error. The axial force measurement bridge output voltage formula is: ; in, This indicates the output voltage of the axial force measurement bridge. to These represent the spatial deformation sensing quantities of each independent strain gauge; This represents the comprehensive axial strain. The full-bridge algorithm not only amplifies the axial principal strain signal through the coordinated operation of the four bridge arms, but also suppresses the non-axial disturbance deformation caused by the additional bending moment by utilizing the physical law of symmetrical cancellation of positive and negative signs.

[0055] The output result is determined by weighted synthesis based on multi-dimensional bridge arm data from eight nodes, overcoming the one-sided measurement errors caused by relying solely on local nodes. Through all the above bridge configurations, the Wheatstone bridge circuit completes hardware-level decoupling of multi-dimensional forces, outputting independent bridge voltage signals.

[0056] See attached document Figure 5 Appendix Figure 6 With appendix Figure 7 In this embodiment, the shield beam 3 transmits the actual working load to the force shaft 206 of the three-dimensional pin sensor 2 under load conditions, forming a three-dimensional composite load at the force shaft 206. This load further generates physical deformation, corresponding to the three-dimensional spatial deformation in the through hole 204 in the vertical direction, the through hole 207 in the horizontal direction, and the thin-walled region of the axial external fixed shaft 201. The strain gauges arranged in each region then undergo resistance changes, converting the mechanical deformation into analog resistance change signals.

[0057] As a conventional explanation of fundamental physical principles, those skilled in the art typically rely on Hooke's Law and the stress-section integral principle from solid mechanics as basic technical support. This principle states that within the elastic limit, the macroscopic force, internal normal stress, and surface physical strain of a solid material are linearly proportional. Based on this physical correlation, the Wheatstone bridge circuit receives the analog resistance change signal, utilizes the orthogonal deformation characteristics of the through-hole structure and the adjacent arm connection logic of the full-bridge circuit to eliminate cross-interference errors, and outputs the decoupled bridge voltage signal. The system then substitutes these independent electrical parameters into the force calculation logic to reconstruct the physical quantities.

[0058] S501, for the quantitative extraction of the horizontal force dimension, the system extracts the output voltage parameter of the through-hole bridge in the vertical direction from the aforementioned hardware circuit. Since this voltage parameter is physically directly related to the deformation caused by the horizontal force, combining Hooke's Law and the stress equivalent transformation algorithm, the system uses the horizontal radial load calculation formula for inverse mechanical deduction. The horizontal radial load calculation formula is as follows: ; in, This represents the horizontal radial load component obtained from the solution; This represents the normal stress generated in the horizontal direction; This represents the physical cross-sectional area where the strain gauge is installed. This indicates the elastic modulus of the pin material; This represents the combined strain generated in the horizontal direction; This indicates the output voltage of the through-hole bridge in the direction of the plumb bob; Indicates the excitation voltage of the bridge power supply; This represents the sensitivity coefficient of the resistance strain gauge.

[0059] In this calculation step, the decoupled voltage change rate is converted into the surface strain of the component, and then multiplied by the material's inherent elastic modulus and effective stress area, achieving a direct mapping from electrical signals to macroscopic horizontal thrust. Regarding the division operations involved in the formula, since both the bridge power supply excitation voltage and the sensitivity coefficient of the resistance strain gauge are non-zero positive constants determined by hardware physical properties, their product terms... Under any normal operating conditions, it behaves as a real number far from zero, which effectively avoids the risk of calculation divergence caused by the denominator approaching 0 in the underlying code logic.

[0060] S502, based on the same mechanical equivalent transformation principle, explores the quantification process of the force components in the plumb direction within an orthogonal plane. The system extracts the output voltage of the horizontal through-hole bridge decoupled in another orthogonal dimension. The system uses the formula for calculating the radial load in the plumb direction to extract the mechanical values ​​in this dimension. The formula for calculating the radial load in the plumb direction is: ; in, This represents the radial load component in the direction of the plumb bob obtained from the solution; This represents the output voltage of the horizontal through-hole bridge. The technical purpose of this calculation logic is to utilize the physical independence of multi-source heterogeneous data in the spatial dimension to successfully isolate two mutually perpendicular radial force components on a single force axis 206 entity, effectively reducing data cross-aliasing interference in complex environments.

[0061] S503, to determine the overall radial force magnitude, it is necessary to synthesize the two orthogonal components at the vector level. As a preferred engineering approach, the system uses a comprehensive radial composite load calculation formula based on a spatial resultant force vector synthesis algorithm to evaluate the overall force amplitude. The comprehensive radial composite load calculation formula is as follows: ; in, Indicates the magnitude of the combined radial load; The operator for calculating the non-negative square root of the sum of squares; This represents the sum of squares of the output voltages of the orthogonal bridge. This step abandons the one-sided logic that relies solely on extreme values ​​in a single direction, and outputs the global force state by comprehensively analyzing dual-axis data. Since the square root internally uses the sum of the squares of two real voltage parameters, this combined value is always greater than or equal to zero throughout the device's operating cycle, mathematically eliminating the singularity risk of program crashes caused by complex numbers.

[0062] S504, after determining the load amplitude, complete 3D force field modeling still requires clarifying the spatial deflection attitude of the radial force. The system introduces geometric trigonometric relationships and uses the formula for calculating the radial load direction angle to determine the angle of the resultant force. The formula for calculating the radial load direction angle is: ; in, Indicates the angle between the combined radial load and the horizontal direction; This represents the inverse trigonometric function operator for calculating the corresponding tangent value. For this inverse trigonometric function division node, the system has built-in logic for abnormal condition alignment and boundary handling. When the output voltage of the through-hole bridge in the plumb direction... When the absolute value of the detected force approaches a set minimum threshold, the system determines that the horizontal force has disappeared. This minimum threshold is determined by the root mean square of the sensor's background white noise amplitude and environmental electromagnetic interference during factory calibration. When this condition is triggered, the algorithm directly configures the resultant force angle to 90 degrees or 270 degrees, thereby compensating for the division error when the divisor is zero and ensuring the continuity of attitude output throughout the entire time domain.

[0063] After completing the comprehensive analysis of the planar radial composite load, the S505 system independently calculates the push-pull force extending along the pin centerline. Based on the pure strain signal after filtering out bending moments using the full-bridge circuit, the system uses the axial force calculation formula to complete the final three-dimensional closed-loop force measurement. The axial force calculation formula is as follows: ; in, Indicates the axial load component; Indicates axial normal stress; This represents the physical cross-sectional area of ​​the strain region in a thin-walled structure. Indicates the equivalent axial structural strain; This indicates the output voltage of the axial force measurement bridge. Through the multi-dimensional weighted derivation and error-proofing verification of S501 to S505 above, the system substitutes the bridge voltage signals output by each independent bridge into the force calculation logic, calculates and outputs the separate radial load components in the vertical direction, the radial load components in the horizontal direction, and the axial load components, and completes the independent measurement of the three-dimensional force on the connecting pin hole of the hydraulic support top beam and the shield beam, providing reliable data support for the subsequent attitude control of the mine roof support.

Claims

1. A method for measuring the three-dimensional force on the connecting pin hole between the top beam and the shield beam of a hydraulic support, characterized in that, include: Under load conditions, the shield beam (3) transmits the actual working load to the force shaft (206) of the three-dimensional pin sensor (2), forming a three-dimensional composite load at the force shaft (206); The three-dimensional composite load acts on the three-dimensional pin sensor (2) to produce physical deformation, and generates three-dimensional spatial deformation in the thin-walled areas of the vertical through hole (204), the horizontal through hole (207) and the axial fixed shaft (201); The second strain gauge (205), the third strain gauge (208), and the first strain gauge (202) arranged in each region change resistance with the three-dimensional spatial deformation, converting mechanical deformation into analog resistance change signals; The Wheatstone bridge circuit receives the analog resistance change signal, uses the orthogonal deformation characteristics of the through-hole structure and the adjacent arm connection logic of the full bridge circuit to eliminate cross interference error, and outputs the decoupled bridge voltage signal. Based on the bridge voltage signals output by each independent bridge, the force calculation logic is substituted to calculate and output the separate radial load components in the plumb direction, the radial load components in the horizontal direction, and the axial load components, thus completing the independent measurement of the three-dimensional force on the connecting pin hole between the hydraulic support top beam and the shield beam.

2. The method for measuring the three-dimensional force on the connecting pin hole of the hydraulic support top beam and the shield beam according to claim 1, characterized in that, The formation of a three-dimensional composite load at the force-bearing axis (206) specifically includes: The shield beam (3) applies the actual working load to the three-dimensional pin sensor (2) under the load condition; The actual working load transmitted to the force shaft (206) is decomposed into mutually orthogonal radial load components in the vertical direction and radial load components in the horizontal direction, as well as axial load components caused by the tilt of the device. The radial load component in the plumb direction, the radial load component in the horizontal direction, and the axial load component together constitute the three-dimensional composite load at the force-bearing axis (206).

3. The method for measuring the three-dimensional force on the connecting pin hole of the hydraulic support top beam and the shield beam according to claim 1, characterized in that, The specific three-dimensional spatial deformation generated in the thin-walled regions of the vertical through hole (204), the horizontal through hole (207), and the axial fixed shaft (201) includes: The radial load component in the vertical direction and the radial load component in the horizontal direction of the three-dimensional composite load act on the vertical through hole (204) and the horizontal through hole (207) of the three-dimensional pin sensor (2) to produce orthogonal composite deformation; The orthogonal composite deformation generates the three-dimensional spatial deformation on the corresponding hole wall surface; The axial load component in the three-dimensional composite load acts on the thin-walled region of the axial fixed shaft (201) of the three-dimensional pin sensor (2), causing elastic deformation. The elastic deformation generates locally amplified axial tensile and compressive deformation in the three-dimensional space.

4. The method for measuring the three-dimensional force on the connecting pin hole of the hydraulic support top beam and the shield beam according to claim 1, characterized in that, Converting mechanical deformation into an analog resistance change signal specifically includes: The second strain gauge (205) and the third strain gauge (208) are synchronously biased in resistance according to the three-dimensional spatial deformation generated on the corresponding hole wall surface; The resistor bias is correspondingly converted and output as the analog resistance change signal; The resistance bias occurs synchronously with the three-dimensional spatial deformation generated by the internal force-bearing region (201-3) after the first strain gauge (202) receives the load; The resistor bias is correspondingly converted and output as the analog resistance change signal; The second strain gauge (205) arranged in the vertical through hole (204) region is specifically subdivided into the fifth strain gauge (205-1) and the sixth strain gauge (205-2), and the third strain gauge (208) arranged in the horizontal through hole (207) region is specifically subdivided into the seventh strain gauge (208-1) and the eighth strain gauge (208-2). The end structure of the axial fixed shaft (201) is divided into the outer fixed shaft (201-1), the thin-walled strain region (201-2) at the stepped transition and the inner internal stress region (201-3). The first strain gauge (202) arranged in the thin-walled strain region (201-2) corresponds to 8 independent fourth strain gauges (201-4).

5. A method for measuring the three-dimensional force on the connecting pin hole of a hydraulic support top beam and a shield beam according to claim 4, characterized in that, The radial measurement steps for the decoupled bridge voltage signal specifically include: The half-bridge measurement loop in the Wheatstone bridge circuit receives the analog resistance change signal corresponding to the via region. Based on the simulated resistance change signal, the orthogonal deformation characteristics of the through-hole structure are used to identify the small vertical hammer-shaped interference strain or the small horizontal crosstalk strain acting in the same direction as the cross interference error. The cross-interference errors are mutually canceled to achieve error elimination; After the error elimination is completed, the output voltage of the through-hole bridge in the plumb direction and the output voltage of the through-hole bridge in the horizontal direction are extracted as the bridge voltage signal after radial decoupling.

6. The method for three-dimensional force measurement of the connecting pin hole between the hydraulic support top beam and the shield beam according to claim 1, characterized in that, The specific steps for measuring the axial direction of the decoupled bridge voltage signal include: The Wheatstone bridge circuit is connected to an independent bridge arm to receive the analog resistance change signal corresponding to the axial region. Based on the simulated resistance change signal, the non-axial interference deformation caused by the additional bending moment is identified as cross interference error using the adjacent arm connection logic of the full-bridge circuit. The cross-interference error is suppressed and eliminated; After the error elimination is completed, the output voltage of the axial force measurement bridge, which amplifies the axial principal strain signal, is extracted as the bridge voltage signal after axial decoupling.

7. The method for three-dimensional force measurement of the connecting pin hole between the hydraulic support top beam and the shield beam according to claim 1, characterized in that, The specific steps for calculating and outputting the separated radial load components in the plumb direction, horizontal direction, and axial direction include: The system analyzes the bridge voltage signal to extract the output voltage of the through-hole bridge in the plumb direction and the output voltage of the through-hole bridge in the horizontal direction; The output voltage of the through-hole bridge in the plumb direction is substituted into the horizontal radial load calculation formula in the force calculation logic to calculate the separated horizontal radial load components. The output voltage of the horizontal through-hole bridge is substituted into the formula for calculating the radial load in the plumb direction in the force calculation logic to calculate the separated radial load component in the plumb direction.

8. The method for three-dimensional force measurement of the connecting pin hole between the hydraulic support top beam and the shield beam according to claim 1, characterized in that, The further comprehensive evaluation steps following the calculation of the separated horizontal radial load component and the separated vertical radial load component specifically include: Extract the output voltage of the aforementioned through-hole bridge in the plumb direction and the output voltage of the through-hole bridge in the horizontal direction; Substitute the output voltage of the through-hole bridge in the plumb direction and the output voltage of the through-hole bridge in the horizontal direction into the comprehensive radial composite load calculation formula to evaluate and obtain the overall force amplitude. Substitute the output voltage of the horizontal through-hole bridge and the output voltage of the vertical through-hole bridge into the formula for calculating the radial load force direction angle, and combine the abnormal working condition alignment and boundary processing logic to determine the resultant force angle. The comprehensive evaluation closed loop of the horizontal radial load component and the vertical radial load component is perfected by combining the overall force amplitude and the resultant force angle. The minimum threshold involved is determined by the root mean square of the sensor background white noise amplitude and the environmental electromagnetic interference during factory calibration.

9. A method for measuring the three-dimensional force on the connecting pin hole of a hydraulic support top beam and a shield beam according to claim 1, characterized in that, The specific steps for calculating and outputting the separated radial load components in the plumb direction, the radial load components in the horizontal direction, and the axial load components include: The system analyzes the bridge voltage signal to extract the output voltage of the axial force measurement bridge; Substitute the output voltage of the axial force measurement bridge into the axial force calculation formula in the force calculation logic for calculation; The closed-loop measurement is completed through the calculation, and the separated axial load components are output.

10. A method for measuring the three-dimensional force on the connecting pin hole of a hydraulic support top beam and a shield beam according to claim 1, characterized in that, The measurement method is based on an assembly architecture, which includes: The inner and outer double ear plates of the top beam (1) are used to fix the position of the three-dimensional pin sensor (2), and the shield beam (3) is used to apply the actual working load to the three-dimensional pin sensor (2); The three-dimensional pin sensor (2) includes, in sequence along the axial direction, an axial fixed shaft (201), a first fixed shaft component (203), a plumb direction through hole (204), a force-bearing shaft (206), a horizontal direction through hole (207), and a second fixed shaft component (209). The first fixed shaft component (203) is installed in the pin hole of the outer ear plate of the top beam (1), and the second fixed shaft component (209) is installed in the pin hole of the inner ear plate of the top beam (1). The force-bearing shaft (206) is located between the first fixed shaft component (203) and the second fixed shaft component (209). The pin hole of the shield beam (3) is directly fitted and installed outside the force-bearing shaft (206) of the three-dimensional pin sensor (2), and the entire three-dimensional pin sensor (2) is axially fixed by the end axial fixed shaft (201) and the nut (2010), forming the overall measurement architecture for performing the measurement method.

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