A large area wide range six-dimensional force automatic calibration device and method

Abstract

A large area and large range six-dimensional force automatic calibration device and method belong to the technical field of sensor measurement and precision assembly. The calibration device uses the upper frame, the table and the four columns of the welding structure to jointly constitute the main bearing frame, and arranges the lateral loading device outside the main bearing frame. In the main loading process, the reaction force generated by the hydraulic cylinder is borne by the main bearing frame as a whole. The lateral loading device is fastened to the base by bolts, and is equipped with a bidirectional hydraulic cylinder. The stable loading of the lateral load is realized by applying tension, and the stability and controllability are improved. The main hydraulic cylinder and the structure bearing plate are carried on the upper frame guide rail through the roller, which can meet the process demand of six-dimensional force calibration of different size sensors. The stability of the whole structure under large force value loading is realized by the high rigidity of the main loading frame and the independent arrangement of the lateral loading device, and the flexible loading of different calibration processes can be realized.

Description

Technical Field

[0001] This invention belongs to the field of sensor metrology and precision assembly technology, and relates to a large-area, large-range six-dimensional force automated calibration device and method. Background Technology

[0002] As a key sensing element in high-end equipment and major engineering projects, piezoelectric quartz force sensors use quartz crystals as force-sensitive elements to convert multidimensional spatial forces / torques into electrical signal outputs. They possess high stiffness and excellent dynamic response characteristics, and are widely used in fields such as engine thrust vector testing, wind tunnel balance aerodynamic measurement, and ship propulsion shafting force monitoring. Large-size piezoelectric quartz sensors, designed for real-time load sensing of large structural components, require a principal vector range exceeding 800kN and a lateral vector range exceeding 200kN. Their effective surface area in in-situ calibration experiments typically needs to reach 900mm × 900mm or more. These large-size, high-range piezoelectric quartz sensors must undergo rigorous six-dimensional force calibration before factory calibration and field service to establish a precise mapping relationship between their input force / torque and output charge. Therefore, developing a calibration device that can simultaneously meet the requirements of "large-size clamping, ultra-high force loading, and multidimensional precise calibration" has become a bottleneck that urgently needs to be overcome in the field of force measurement technology for large equipment.

[0003] Currently, scholars and research institutions both domestically and internationally have conducted extensive research in the field of six-dimensional force calibration devices. The parallel shaft-mounted piezoelectric six-dimensional force / torque sensor and its calibration method proposed by Jia Zhenyuan et al. achieve spatial six-dimensional force measurement and calibration through a four-point supported parallel structure; however, the effective loading area of ​​the accompanying calibration device is relatively small. Liu Wei et al. designed a 200kN six-dimensional high-force sensor and its calibration platform based on a Stewart structure, verifying the effectiveness of the parallel load-sharing measurement principle under large load scenarios. However, this platform is mainly used for calibrating sensors with medium loads (200kN level). When the loading force increases to the 1000kN level, the structural stiffness and deformation resistance of its calibration bench face severe challenges. Zhao Yanzhi et al. disclosed a large-scale multi-dimensional force sensor calibration loading stage (Chinese Invention Patent CN201010103946.2), which consists of an upper cross, a loading stage column, a lower cross, and loading units. The calibration loading of the multi-dimensional force sensor is achieved by combining the loading units at different installation positions. Its advantages include a simple and compact structure and a large loading range. However, the effective working surface of this device is still limited, making it difficult to accommodate the full-domain clamping requirements of large-size force measuring devices. Zhao Tieshi et al. from Yanshan University proposed a self-calibrating heavy-duty parallel four-dimensional force measuring stage and its calibration loading system. Addressing the research and development needs of the aerospace field for heavy-duty, large-area multi-dimensional force measuring stages, it achieves four-dimensional force measurement and self-calibration by constructing mechanically decoupled force measuring branches. However, this force measuring stage is only suitable for four-dimensional force measurement scenarios and does not possess the complete calibration capability for six-dimensional forces (three-dimensional force + three-dimensional torque).

[0004] In terms of automation of the calibration process, existing large-scale calibration devices generally have a low level of automation. Especially when facing the requirements of multi-dimensional force composite loading, synchronous and coordinated composite loading of multi-directional loads, the loading logic of each load dimension is often isolated, lacking a deeply integrated automated feedback control system, which seriously restricts calibration efficiency and the accurate capture of multi-dimensional coupling errors.

[0005] In summary, the existing technology lacks a six-dimensional force calibration bench that can simultaneously meet the following comprehensive indicators: (1) ultra-large load loading capacity with a principal loading force of 1000kN and a lateral loading force of 300kN; (2) a large clamping space with an effective area of ​​1200mm×1200mm; and (3) complete automated independent and composite calibration capabilities for six-dimensional forces (Fx, Fy, Fz, Mx, My, Mz). Therefore, it is urgent to develop a large-area, large-range automated six-dimensional force calibration device to provide key technical support for the accurate measurement and engineering application of this type of sensor. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention provides an automated six-dimensional force calibration device and method with a large area and a large range. This invention utilizes a 100-ton hydraulic cylinder to increase the loading range of the calibration device, and achieves six-dimensional force loading at high force values ​​through a high-rigidity main loading frame and independently arranged lateral loading devices, while expanding the effective loading area to 1200mm × 1200mm. An automated hydraulic control system enables flexible loading for different calibration processes, meeting the process requirements for variable loading point six-dimensional force calibration of sensors of different sizes.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A large-area, large-range six-dimensional force automated calibration device includes a base, a main loading device, three lateral loading devices, and a hydraulic control system. The base serves as the supporting structure for the entire calibration device. All components are mounted on the base surface, which is precision-milled to a surface roughness of Ra1.6 and a flatness of 0.05, providing a high-precision horizontal reference mounting surface for the main and lateral loading devices. The base is fixed to the ground with anchor bolts, providing a rigid reference for the main and lateral loading devices. The main loading device is rigidly connected to the base via a column below the upper frame. The three lateral loading devices are fixed to the base at their bottoms and arranged in a triangular pattern around the main loading device. The hydraulic control system is connected to the main and lateral hydraulic cylinders via hydraulic lines, enabling control of synchronous, stepped, or alternating loading of the main and lateral loads, providing a stable power source for the coupling error calibration of the six-dimensional force sensor.

[0008] The main loading device has a loading range of 1000kN and the ability to resist overall structural deformation during loading. The main loading point can be changed according to requirements. The main loading device includes a platform, columns, structural load-bearing plate, upper frame, worm gear mechanism, worm gear mechanism connecting plate, first connecting plate, rollers, main hydraulic cylinder, guide rail, T-nut, and second connecting plate. Specifically: The tabletop is a rectangular solid steel plate milled on both the top and bottom surfaces. The top surface has 121 threaded holes spaced 100mm apart and 9 countersunk holes arranged in an X-shape. A through-hole circular mounting hole is located at each of the four corners. The columns consist of threaded hollow rods and circular mounting flanges. Threads are machined at both ends of the columns, and mounting flanges and triangular ribs are welded to the bottom of the threads. The structural load-bearing plate consists of a base plate with an inverted trapezoidal cross-section and two vertical plates. A second circular mounting hole and a circular array of bolt holes are machined in the center of the base plate. Countersunk bolt holes are machined on both sides along the length of the base plate. The two vertical plates are welded to the upper surface of the base plate and have bolt holes on the side furthest from the base plate. The top frame is a rectangular frame formed by riveting and welding steel plates. Mounting surfaces are machined on both the top and bottom. A rectangular through-hole is located in the center of the frame. Two through-slots are machined on each side along the length of the frame, and through-hole circular mounting holes are located at each of the four corners. The upper frame, platform, and four columns together constitute the main load-bearing frame. The specific connection method is as follows: the upper threaded shaft section of each column passes through the third circular mounting hole in the upper frame and is connected via a T-nut; its lower threaded shaft section passes through the first circular mounting hole in the platform and is connected via a T-nut. A guide rail is mounted on the upper frame's mounting surface. The worm gear mechanism connecting plate is an L-shaped steel plate, with pre-drilled mounting holes and bolt holes for the worm gear mechanism on its vertical plate, and a through hole at the bottom. The worm gear mechanism is bolted to the worm gear mechanism connecting plate and then fixed to the mounting surface on the upper frame. The upper surface of the platform is bolted to the second connecting plate.

[0009] The main hydraulic cylinder first passes through the mounting hole in the center of the structural support plate and is fixedly connected. Next, the vertical plate of the structural support plate passes through the rectangular through hole in the center of the upper frame and is fixedly connected to the straight grooves on both sides of the upper frame through countersunk holes. Finally, the vertical plate of the structural support plate is fixedly connected to the first connecting plate. The first connecting plate is a rectangular frame formed by welding four vertical plates, each with a through hole. Rollers are fixed on the vertical plates on both sides of the first connecting plate, and the rollers are mounted on guide rails, forming a degree of freedom for adjustment in the horizontal plane. During adjustment, the worm gear mechanism is temporarily connected to the first connecting plate with bolts. The worm extension is changed by rotating the handwheel of the worm gear mechanism to change the horizontal position of the main hydraulic cylinder. After the main hydraulic cylinder moves to the appropriate position, the connecting bolts between the worm gear mechanism and the first connecting plate are removed, and the structural support plate and the upper frame are directly locked together with mounting bolts. The structural support plate and the upper frame are rigidly fitted together, causing the rollers to move vertically upward away from the guide rails, completely eliminating the adjustment gap and constructing a rigid loading chain.

[0010] The upper surface of the base and the lower surface of the platform are fixedly connected through the countersunk hole of the platform. This structure ensures the coaxiality of the loading axis under high load conditions by transmitting the reaction force generated by the hydraulic cylinder to the closed frame through the structural load-bearing plate.

[0011] The lateral loading device has both tensile and compressive loading capabilities, with ranges of 200kN and 300kN respectively. It also features horizontal and vertical position adjustment capabilities. Structurally, the lateral loading device is independent of the main frame and is bolted to the base. This arrangement significantly improves the lateral stiffness of the device while supporting lateral span adjustment within the range of 0-280mm. The lateral loading device includes a lateral base frame, a lateral adapter plate, a lateral loading frame, a lateral flange, a lateral hydraulic cylinder, a lateral lifting block, and a lateral worm gear mechanism. The lateral base frame includes a base plate and three vertical plates forming an "I" shape, including a central vertical plate and two side vertical plates. The central vertical plate has a circular weight-reducing hole. The lateral lifting block is a rectangular hard rubber block with a semi-circular groove and bolt holes at its bottom. The lateral adapter plate is a plate with four T-slots on its upper surface and countersunk holes at its four corners. The lateral adapter plate is fixedly connected to the upper surface of the lateral base frame. The lateral loading frame includes a base plate and a structure with three vertical plates surrounding an opening on one side. The front vertical plate has a large vertical groove at its center, surrounded by four smaller vertical grooves. The side vertical plates have weight-reduction holes. The lateral loading frame is connected to the T-slots of the lateral adapter plate via T-slot bolts, supporting horizontal position adjustment of the lateral loading frame. The lateral worm gear mechanism is fixedly connected to the base plate of the lateral loading frame, surrounded by its three vertical plates. The worm flange of the lateral worm gear mechanism is fixedly connected to the lateral lifting block, and the semi-circular groove of the lateral lifting block mates with the outer diameter of the lateral hydraulic cylinder. The lateral hydraulic cylinder is a bidirectional hydraulic cylinder. Its cylinder body flange and lateral flange are located on the inner and outer sides of the front vertical plate of the lateral loading frame, respectively, and are connected by bolts. When the bolts of the lateral hydraulic cylinder cylinder body flange are loosened, the vertical position of the lateral hydraulic cylinder can be adjusted by changing the worm extension through the lateral worm gear mechanism. When the lateral hydraulic cylinder reaches the appropriate position, the bolts of the lateral hydraulic cylinder cylinder body flange are tightened, thereby cooperating with the main loading to achieve stable calibration of the six-dimensional force at the variable loading point.

[0012] The hydraulic control system includes a high-pressure pump station, a proportional relief valve, a multi-channel solenoid directional valve, a precision pressure sensor, and an oil tank. The hydraulic control system is fixedly connected to the base via foot anchors on the oil tank. It controls the pressure and movement of the main hydraulic cylinder and the lateral hydraulic cylinder. By adjusting the output force of each hydraulic cylinder, the hydraulic control system achieves a pressure control accuracy of no less than 0.5%FS, enabling synchronous, stepped, or alternating loading of main and lateral loads, and providing a stable power source for the coupling error calibration of the six-dimensional force sensor.

[0013] A method for automated calibration of six-dimensional forces over a large area and with a large range, based on the aforementioned automated calibration device for six-dimensional forces, includes the following steps: Step 1: Preprocess the force measuring instrument to be calibrated.

[0014] Clean the upper surface of the force gauge and the area around the bolt holes. Clean the upper surface with anhydrous ethanol to thoroughly remove oil and dust and prevent impurities from affecting the calibration results.

[0015] Step 2: Adjust the position of the hydraulic cylinder on the calibration platform.

[0016] Establish a spatial rectangular coordinate system with the countersunk hole at the center of the second connecting plate as the origin O (e.g., Figure 1 (As shown in the diagram) The calibration platform hydraulic cylinders include one main hydraulic cylinder and three lateral hydraulic cylinders. The three lateral hydraulic cylinders are a first lateral hydraulic cylinder, a second lateral hydraulic cylinder, and a third lateral hydraulic cylinder. The second and third lateral hydraulic cylinders are located on either side of the first lateral hydraulic cylinder, forming a triangular arrangement. If only unidirectional force non-variable loading point calibration in the X, Y, and Z directions is required, then it is not necessary to move the hydraulic cylinder positions; otherwise, the hydraulic cylinder positions need to be manually adjusted.

[0017] When calibrating the Mz torque, it is necessary to adjust the relative horizontal position of the second and third lateral hydraulic cylinders, loosen the bolts connecting the lateral loading device and the base, and move them to the X+ and X- directions respectively, so that the bolt holes of the base in the lateral loading device are aligned with the bolt holes of the base. Apply pre-tightening force to the bolts according to the standard, and coordinate with the movement of the lateral loading frame on the lateral adapter plate to reach the preset position. When calibrating My / Mx, it is necessary to adjust the relative vertical positions of the second and third lateral hydraulic cylinders. Loosen the bolts connecting the lateral flange to the second and third lateral hydraulic cylinders, rotate the handwheel of the lateral worm gear mechanism to control the raising and lowering of the second and third lateral hydraulic cylinders, and when the second and third lateral hydraulic cylinders reach the preset positions, reconnect the lateral flange to the second and third lateral hydraulic cylinders with bolts to fix the position of the hydraulic cylinders.

[0018] Step 3: Calibrate the force gauge.

[0019] Step 3.1, Installation of the force gauge.

[0020] Connect the force gauge to the second connecting plate with eight M12 bolts to ensure that the position of the force gauge does not slip during the calibration process and that its lower surface is tightly bonded to the second connecting plate; connect the calibration block to the force gauge with eight M12 bolts, ensuring that the calibration block is centered on the force gauge during the connection process.

[0021] Step 3.2, set the calibration scheme.

[0022] The use of the calibration bench requires designing a complete calibration scheme: select the corresponding loading curve according to the range of the dynamometer, select the loading hydraulic cylinder to be used, set the upper and lower limit force values, the number of steps, the pressure holding time and the action time step of the hydraulic cylinder in a step loading manner, so as to obtain the calibration scheme.

[0023] Step 3.3: Calibration operation of the dynamometer.

[0024] Based on the calibration scheme set in step 3.2, ensure that the dynamometer is installed correctly and there are no personnel around the calibration bench, simultaneously start the data acquisition software to synchronously collect the output of the dynamometer, and click the loading button to complete the automatic calibration action. Specifically, after loading starts, the hydraulic control system judges whether the loading force value is reached. If the loading force value is reached, pressure holding is performed and it is judged whether the pressure holding time is reached. If the pressure holding time is reached, loading of the next time step is carried out, and it is further judged whether all time steps are completed. If all time steps are completed, the loading action ends.

[0025] Beneficial effects of the present invention: (1) High bearing rigidity and strong deformation resistance, which significantly improve the axis coaxiality and decoupling accuracy of high-load calibration. The main-direction bearing frame composed of the upper frame, the table top and the upright columns can integrally and closedly bear the large-force reaction force of the main-direction hydraulic cylinder, ensuring the axis coaxiality under hundred-ton-level loading; the independently external lateral loading device structurally eliminates main-lateral interference, effectively suppresses the deflection and parasitic displacement of the bench caused by lateral loading, and greatly reduces the inter-dimensional coupling interference of the spatial force system.

[0026] (2) The effective loading area is wide, with excellent large-size spatial compatibility. Through the spatial separation and external layout of the core loading mechanism, the effective loading area is expanded to more than 1200mm×1200mm, which overcomes the limitation that the traditional calibration table top is restricted by the space of mechanical components and is generally less than one thousand millimeters, and can be compatible with full-area multi-point testing of ultra-large-size, high-span piezoelectric quartz sensors.

[0027] (3) Accurate simulation of full-dimensional six-dimensional force and spatial composite moment can be realized. Through the coordinated operation of one main-direction loading device and three lateral loading devices symmetrically arranged in a "delta" shape, all six-dimensional components including the linear forces Fx, Fy, Fz and the torques Mx, My, Mz are fully covered; the lateral hydraulic cylinder adopts a bidirectional tensile loading mode, which can be smoothly converted into a spatial composite moment in combination with height and span adjustment, to truly simulate the complex service conditions of large components.

[0028] (4) Strong synchronous automatic composite loading capability. The pressure control accuracy of the hydraulic control system is better than 0.5%FS, which can realize synchronous, step or alternating automatic composite loading of multi-directional loads according to program control instructions. While greatly shortening the calibration cycle, it is beneficial to dynamically capture and eliminate the coupling error caused by cross interference of loads in various dimensions. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of a large-area, large-range six-dimensional force automated calibration device according to the present invention. Figure 2 for Figure 1 Internal structure diagram of the main loading device 2; Figure 3 for Figure 1 Internal structure diagram of the lateral loading device 3; Figure 3 (a) in the figure is a detailed view of the lateral structure of the lateral loading device 3; Figure 3 (b) is a rear view of the detailed structure of the lateral loading device 3; Figure 4 This is a flowchart of the measurement method described in this invention; Figure 5 For example, F X F Y F Z Loading principle diagram; Figure 6 M in the example Z Loading principle diagram; Figure 7 M in the example X Loading principle diagram; Figure 8 M in the example Y Loading principle diagram.

[0030] In the diagram: 1. Base; 2. Main loading device; 3. Lateral loading device; 4. Hydraulic control system; 5. Calibration block; 6. Force gauge; 2-1 Tabletop; 2-2 Columns; 2-3 Structural load-bearing plate; 2-4 Upper frame; 2-5 Worm gear mechanism; 2-6 Worm gear mechanism connecting plate; 2-7 First connecting plate; 2-8 Roller; 2-9 Main hydraulic cylinder; 2-10 Guide rail; 2-11 T-nut; 2-12 Second adapter plate; 3-1 Lateral base frame; 3-2 Lateral adapter plate; 3-3 Lateral loading frame; 3-4 Lateral flange; 3-5 Lateral hydraulic cylinder; 3-6 Lateral lifting block; 3-7 Lateral worm gear mechanism; 3-5-1 First lateral hydraulic cylinder; 3-5-2 Second lateral hydraulic cylinder; 3-5-3 Third lateral hydraulic cylinder. Detailed Implementation

[0031] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0032] This embodiment provides a large-area, large-range, six-dimensional force automated calibration device, such as... Figure 1As shown, the calibration device includes a base 1, a main loading device 2, three lateral loading devices 3, and a hydraulic control system 4. The base 1 is the supporting structure for the entire calibration device. All structures are mounted on the base surface, which is precision milled to a surface roughness of Ra1.6 and a flatness of 0.05, providing a high-precision horizontal reference mounting surface for the main loading device 2 and the lateral loading devices 3. The bottom of the base 1 is fixed to the ground with anchor bolts, providing a rigid reference for the main loading device 2 and the lateral loading devices 3. The main loading device 2 is rigidly connected to the base 1 via a column 2-2 below the upper frame 2-4. The three lateral loading devices 3 are fixed to the base 1 at their bottoms and arranged in a triangular pattern around the main loading device 2. The hydraulic control system 4 is connected to the main hydraulic cylinder 2-9 and the lateral hydraulic cylinder 3-5 via hydraulic pipelines, enabling control of synchronous, stepped, or alternating loading of the main and lateral loads, providing a stable power source for the coupling error calibration of the six-dimensional force sensor.

[0033] The main loading device 2 has a loading range of 1000kN and the ability to resist overall structural deformation during loading, and can change the main loading point according to requirements; the specific structure of the main loading device 2 is as follows: Figure 2 As shown, it includes a tabletop 2-1, columns 2-2, a structural load-bearing plate 2-3, an upper frame 2-4, a worm gear mechanism 2-5, a worm gear mechanism connecting plate 2-6, a first connecting plate 2-7, rollers 2-8, a main hydraulic cylinder 2-9, a guide rail 2-10, a T-nut 2-11, and a second adapter plate 2-12. Specifically: The platform 2-1 is a rectangular solid steel plate milled on both the top and bottom surfaces. The top surface has 121 threaded holes spaced 100mm apart and 9 countersunk holes arranged in an X-shape. A first circular mounting hole is located at each of the four corners. The column 2-2 includes a threaded hollow rod and a circular mounting flange. Threads are machined at both ends of the column 2-2, and mounting flanges and triangular ribs are welded to the bottom of the threads. The structural load-bearing plate 2-3 includes a base plate with an inverted trapezoidal cross-section and two vertical plates. A second circular mounting hole and a circular array of bolt holes are machined in the center of the base plate. Countersunk bolt holes are machined on both sides along the length of the base plate. The two vertical plates are welded to the upper surface of the base plate and have bolt holes on the side furthest from the base plate. The top frame 2-4 is a rectangular frame formed by riveting and welding steel plates. It has mounting surfaces machined on both the top and bottom. A rectangular through hole is located in the center of the frame. Two through straight slots are machined on each side along the length of the frame, and a third circular mounting hole is located at each of the four corners. The upper frame 2-4, platform 2-1, and four columns 2-2 together constitute the main load-bearing frame. The specific connection method is as follows: the upper threaded shaft of the column 2-2 passes through the third circular mounting hole of the upper frame 2-4 and is connected by a T-nut 2-11; its lower threaded shaft passes through the first circular mounting hole of the platform 2-1 and is connected by a T-nut 2-11. A guide rail 2-10 is mounted on the upper frame 2-4. The worm gear mechanism connecting plate 2-6 is an L-shaped steel plate with pre-drilled mounting holes and bolt holes for the worm gear mechanism 2-5 on its vertical plate, and a through hole at the bottom. The worm gear mechanism 2-5 and the worm gear mechanism connecting plate 2-6 are connected by bolts and then fixed to the mounting plane on the upper frame 2-4. The upper surface of the platform 2-1 is connected to the second adapter plate 2-12 by bolts. The main hydraulic cylinder 2-9 first passes through the mounting hole in the center of the structural support plate 2-3 and is fixedly connected. Next, the vertical plate of the structural support plate 2-3 passes through the rectangular through hole in the center of the upper frame 2-4 and is fixedly connected to the straight grooves on both sides of the upper frame 2-4 through countersunk holes. Finally, the vertical plate of the structural support plate 2-3 is fixedly connected to the first connecting plate 2-7. The first connecting plate 2-7 is a rectangular frame formed by welding four vertical plates, each with a through hole. Rollers 2-8 are fixed to the vertical plates on both sides of the first connecting plate 2-7, and the rollers 2-8 are mounted on guide rails 2-10, forming a degree of freedom for adjustment in the horizontal plane.During the adjustment process, the worm gear mechanism 2-5 is temporarily connected to the first connecting plate 2-7 by bolts. The extension of the worm is changed by rotating the handwheel of the worm gear mechanism 2-5 to change the horizontal position of the main hydraulic cylinder 2-9. After the main hydraulic cylinder 2-9 moves to the appropriate position, the connecting bolts between the worm gear mechanism 2-5 and the first connecting plate 2-7 are removed. Then, the structural load-bearing plate 2-3 and the upper frame 2-4 are directly locked by the installation bolts. The structural load-bearing plate 2-3 and the upper frame 2-4 are rigidly attached, so that the roller 2-8 moves vertically upward away from the guide rail 2-10, completely eliminating the adjustment gap and constructing a rigid loading chain.

[0034] The upper surface of the base 1 and the lower surface of the platform 2-1 are fixedly connected through the countersunk hole of the platform 2-1. This structure ensures the coaxiality of the loading axis under high load conditions by transmitting the reaction force generated by the hydraulic cylinder to the closed frame through the structural load-bearing plate.

[0035] The lateral loading device 3 has both tensile and compressive loading capabilities, with ranges of 200kN and 300kN respectively. It also has the ability to adjust its horizontal and vertical positions. Structurally, the lateral loading device 3 is independent of the main frame and is bolted to the base 1. This arrangement significantly improves the lateral stiffness of the device while supporting lateral span adjustment within the range of 0-280mm. A schematic diagram of the lateral loading device 3 is shown below. Figure 3As shown, the system includes a lateral base frame 3-1, a lateral adapter plate 3-2, a lateral loading frame 3-3, a lateral flange 3-4, a lateral hydraulic cylinder 3-5, a lateral lifting block 3-6, and a lateral worm gear mechanism 3-7. The lateral base frame 3-1 includes a base plate and three vertical plates forming an "I" shape, comprising a central vertical plate and two side vertical plates. The central vertical plate has a circular weight-reducing hole. The lateral lifting block 3-6 is a rectangular hard rubber block with a semi-circular groove and bolt holes at its bottom. The lateral adapter plate 3-2 is a plate with four T-slots on its upper surface and countersunk holes at its four corners. The lateral adapter plate 3-2 is fixedly connected to the upper surface of the lateral base frame 3-1. The lateral loading frame 3-3 includes a base plate and a structure with three vertical plates surrounding an opening on one side. A large vertical groove is located at the center of the front vertical plate, surrounded by four smaller vertical grooves. Weight-reduction holes are located on the side vertical plates. The lateral loading frame 3-3 is connected to the T-slot of the lateral adapter plate 3-2 via T-slot bolts, supporting horizontal position adjustment of the lateral loading frame 3-3. The lateral worm gear mechanism 3-7 is fixedly connected to the base plate of the lateral loading frame 3-3, surrounded by its three vertical plates. The worm flange of the lateral worm gear mechanism 3-7 is fixedly connected to the lateral lifting block 3-6, and the semi-circular groove of the lateral lifting block 3-6 mates with the outer diameter of the cylinder of the lateral hydraulic cylinder 3-5. The lateral hydraulic cylinder 3-5 is a bidirectional hydraulic cylinder. Its cylinder body flange and lateral flange 3-4 are located on the inner and outer sides of the front vertical plate of the lateral loading frame 3-3, respectively, and are connected by bolts. When the bolts of the lateral hydraulic cylinder 3-5 cylinder body flange are loosened, the vertical position of the lateral hydraulic cylinder 3-5 can be adjusted by changing the worm extension amount through the lateral worm gear mechanism 3-7. When the lateral hydraulic cylinder 3-5 reaches the appropriate position, the bolts of the lateral hydraulic cylinder 3-5 cylinder body flange are tightened, thereby cooperating with the main loading to achieve stable calibration of the six-dimensional force at the variable loading point.

[0036] The hydraulic control system 4 comprises a high-pressure pump station, a proportional relief valve, a multi-channel solenoid directional valve, a precision pressure sensor, and an oil tank. The hydraulic control system 4 is fixedly connected to the base 1 via foot anchors on the oil tank. It controls the pressure and movement of the main hydraulic cylinders 2-9 and the lateral hydraulic cylinders 3-5. The hydraulic control system 4 adjusts the output force of each hydraulic cylinder through a proportional control algorithm, achieving a pressure control accuracy of no less than 0.5%FS. It can realize synchronous, stepped, or alternating loading of main and lateral loads, providing a stable power source for the coupling error calibration of the six-dimensional force sensor.

[0037] This embodiment also provides an automated calibration method for a large-area, large-range six-dimensional force. A piezoelectric force gauge 6 with a principal vector range of 500kN, a lateral vector range of 200kN, and an overall size of 1000×500mm is selected. The force gauge 6 is calibrated using the aforementioned automated calibration device for a large-area, large-range six-dimensional force, including the following steps: Step 1: Preprocess the force gauge 6 to be calibrated.

[0038] Clean the upper surface of the force gauge 6 and the area around the bolt holes. Use anhydrous ethanol and non-woven cloth to clean the upper surface of the force gauge 6 to thoroughly remove oil and dust. Clean the bolt holes on the upper and lower surfaces of the force gauge 6. Use a wire brush to remove iron filings and foreign objects from the inner diameter of the bolt holes and apply lubricating oil to ensure the tightness of the bolt connection and to prevent impurities from affecting the calibration results.

[0039] Step 2: Adjust the position of the hydraulic cylinder on the calibration platform.

[0040] Establish a spatial rectangular coordinate system with the countersunk hole at the center of the second adapter plate 2-12 as the origin O (e.g., Figure 1 (As shown); the calibration platform hydraulic cylinders consist of one main hydraulic cylinder 2-9 and three lateral hydraulic cylinders 3-5. The three lateral hydraulic cylinders 3-5 include a first lateral hydraulic cylinder 3-5-1, a second lateral hydraulic cylinder 3-5-2, and a third lateral hydraulic cylinder 3-5-3. The second lateral hydraulic cylinder 3-5-2 and the third lateral hydraulic cylinder 3-5-3 are located on both sides of the first lateral hydraulic cylinder 3-5-1, forming a triangular arrangement. In the embodiment, F X F Y F Z Loading principle diagram as follows Figure 5 As shown. If only the unidirectional force non-variable loading point calibration in the X, Y, and Z directions is required, then the main hydraulic cylinder 2-9, the first lateral hydraulic cylinder 3-5-1, and the second lateral hydraulic cylinder 3-5-2 are used to apply loads parallel to the Z-axis, Y-axis, and X-axis of the coordinate system, respectively, pointing towards the origin of the coordinate system. Figure 6 As shown; there is no need to move the hydraulic cylinder position, otherwise the hydraulic cylinder position needs to be manually adjusted; use a level to measure the piston rod position of one main hydraulic cylinder 2-9 and three lateral hydraulic cylinders 3-5 to ensure centering during loading and avoid biased loading.

[0041] When calibrating the Mz torque, two lateral hydraulic cylinders are needed, parallel to the X-axis of the coordinate system, and applied loads at a certain span interval in the Y-axis direction, such as... Figure 7 As shown, it is necessary to adjust the relative horizontal position of the second lateral hydraulic cylinder 3-5-2 and the third lateral hydraulic cylinder 3-5-3, loosen the bolts connecting the lateral loading device 3 and the base 1, and move them to the X+ and X- directions respectively, so that the bolt holes of the base 3-1 in the lateral loading device 3 are aligned with the bolt holes of the base 1. Apply pre-tightening force to the bolts according to the standard, and move the lateral loading frame 3-3 on the lateral adapter plate 3-2 to reach the preset position. When performing My / Mx calibration, two lateral hydraulic cylinders are needed, parallel to the Y-axis of the coordinate system, and applied loads at a certain span interval in the X-axis direction, such as... Figure 8As shown, it is necessary to adjust the relative vertical positions of the second lateral hydraulic cylinder 3-5-2 and the third lateral hydraulic cylinder 3-5-3. Loosen the bolts connecting the lateral flange 3-4 to the second lateral hydraulic cylinder 3-5-2 and the third lateral hydraulic cylinder 3-5-3, rotate the handwheel of the lateral worm gear mechanism 3-7 to control the lifting and lowering of the second lateral hydraulic cylinder 3-5-2 and the third lateral hydraulic cylinder 3-5-3. When the second lateral hydraulic cylinder 3-5-2 and the third lateral hydraulic cylinder 3-5-3 reach the preset position, reconnect the lateral flange 3-4 to the second lateral hydraulic cylinder 3-5-2 and the third lateral hydraulic cylinder 3-5-3 with bolts to fix the position of the hydraulic cylinders.

[0042] Step 3: Calibrate the force gauge 6.

[0043] Step 3.1, Installation of force gauge 6.

[0044] The force gauge 6 is connected to the second adapter plate 2-12 with eight M12 bolts to ensure that the position of the force gauge 6 does not slip during the calibration process and that its lower surface is tightly bonded to the second adapter plate 2-12; the calibration block 5 is connected to the force gauge 6 with eight M12 bolts, ensuring that the calibration block 5 is located at the center of the force gauge 6 during the connection process.

[0045] Step 3.2, set the calibration scheme.

[0046] The use of the calibration platform requires the design of a complete calibration scheme. Select the appropriate loading curve according to the 6 range of the force measuring instrument, select the loading hydraulic cylinder to be used, and set the upper and lower limit force values ​​from 0kN to 500kN, the number of steps to 5, the holding time to 5s, and the hydraulic cylinder action time step to a total of 16 steps according to the step loading method. After saving the scheme in the system, it can be used to obtain the calibration scheme.

[0047] Step 3.3, Calibration of force gauge 6.

[0048] Select the preset calibration scheme, ensure the force gauge 6 is installed correctly and there are no personnel around the calibration platform, and simultaneously open the data acquisition software to collect the output of the force gauge 6. Click the load button to complete the automatic calibration process. Specifically, as follows... Figure 4 As shown, after loading begins, the hydraulic control system 4 determines whether the loading force value has been reached. If the loading force value has been reached, pressure is maintained and it is determined whether the pressure maintenance time has been reached. If the pressure maintenance time has been reached, the loading of the next time step is carried out. The system continues to determine whether all time steps have been completed. If all time steps have been completed, the loading action ends and the system waits for data export.

[0049] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A large-area, large-range, six-dimensional force automated calibration device, characterized in that, The six-dimensional force automatic calibration device includes a base (1), a hydraulic control system (4), and a main loading device (2) and a lateral loading device (3) installed on the base (1); The base (1) is fixedly connected to the ground at its bottom; The main loading device (2) is rigidly connected to the base (1) through the column (2-2) below the upper frame (2-4), and can change the main loading point according to the requirements. It includes a platform (2-1), column (2-2), structural load-bearing plate (2-3), upper frame (2-4), worm gear mechanism (2-5), worm gear mechanism connecting plate (2-6), first connecting plate (2-7), roller (2-8), main hydraulic cylinder (2-9), guide rail (2-10), and second adapter plate (2-12). The upper frame (2-4) and the platform (2-1) are connected by the columns (2-2) arranged at the four corners to form a main load-bearing frame. The guide rail (2-10) is installed on the upper surface of the upper frame (2-4). The platform (2-1) is installed on the base (1), and the second adapter plate is installed on the upper surface of the platform (2-1). (2-12); The worm gear mechanism (2-5) is connected to the worm gear mechanism connecting plate (2-6) and then fixed on the upper frame (2-4); The main hydraulic cylinder (2-9) is installed on the structural support plate (2-3), and the structural support plate is fixedly connected to the first connecting plate (2-7); The first connecting plate (2-7) is mounted on the guide rail (2-10) through the roller (2-8) to form an adjustment degree of freedom in the horizontal plane; During the adjustment process, the worm gear mechanism (2-5) is temporarily connected to the first connecting plate (2-7), and the position of the main hydraulic cylinder (2-9) is changed by rotating the worm gear mechanism (2-5). When it moves to the appropriate position, the connecting bolts between the worm gear mechanism (2-5) and the connecting plate (2-7) are removed, and the structural support plate (2-3) and the upper frame (2-4) are locked to form a rigid loading chain; There are three lateral loading devices (3), all of which are fixed on the base (1) and arranged in a triangular shape around the main loading device (2); the lateral loading device (3) has two loading modes, tension and compression, and can realize horizontal and vertical position adjustment; The hydraulic control system (4) is connected to the main hydraulic cylinder (2-9) and the lateral hydraulic cylinder (3-5) of the main loading device (2) through hydraulic pipelines. It can control the synchronous, stepped or alternating loading of the main and lateral loads to provide a stable power source.

2. The large-area, large-range, six-dimensional force automated calibration device according to claim 1, characterized in that, In the main loading device (2): The main loading device (2) has a loading range of 1000kN and the ability to resist overall structural deformation during loading. The tabletop (2-1) is a rectangular solid plate with threaded holes and countersunk holes arranged in an X-shape on the upper surface, and through-holes in the four corners. The column (2-2) includes a threaded hollow rod and a circular mounting flange. The column (2-2) has threads at both ends, and the bottom of the threads is provided with a mounting flange and a triangular rib. The structural load-bearing plate (2-3) includes a base plate with an inverted trapezoidal cross section and two vertical plates. The two vertical plates are installed on the base plate and have bolt holes. A second circular mounting hole and a circular array of bolt holes are machined in the center of the base plate. Countersunk bolt holes are machined on both sides of the base plate along its length. The upper frame (2-4) is a rectangular frame with mounting planes on both the top and bottom. A rectangular through hole is left in the center of the frame, and two through straight slots are machined on each side along the length direction. A third circular mounting hole is left at each of the four corners. The connecting plate (2-6) of the worm gear mechanism is an L-shaped steel plate, and its vertical plate is reserved with mounting holes and bolt holes for the worm gear mechanism (2-5); The main hydraulic cylinder (2-9) passes through the second circular mounting hole in the center of the structural support plate (2-3) and is fixedly connected. The vertical plate of the structural support plate (2-3) passes through the rectangular through hole in the center of the upper frame (2-4) and is fixedly connected to the straight grooves on both sides of the upper frame (2-4) through the countersunk hole. The vertical plate of the structural support plate (2-3) is fixedly connected to the first connecting plate (2-7). The first connecting plate (2-7) is a rectangular frame formed by four vertical plates. Rollers (2-8) are fixed on the vertical plates on both sides of the first connecting plate (2-7). The rollers (2-8) are mounted on the guide rail (2-10) to form a degree of freedom of adjustment in the horizontal plane.

3. The large-area, large-range, six-dimensional force automated calibration device according to claim 2, characterized in that, During the adjustment process, the worm gear mechanism (2-5) in the main loading device (2) is temporarily connected to the first connecting plate (2-7) by bolts. The extension of the worm is changed by rotating the handwheel of the worm gear mechanism (2-5) to change the horizontal position of the main hydraulic cylinder (2-9). After the main hydraulic cylinder (2-9) moves to the appropriate position, the connecting bolts between the worm gear mechanism (2-5) and the first connecting plate (2-7) are removed, and the structural support plate (2-3) and the upper frame (2-4) are locked. The structural support plate (2-3) and the upper frame (2-4) are rigidly attached, so that the roller (2-8) moves vertically upward away from the guide rail (2-10), completely eliminating the adjustment gap and constructing a rigid loading chain.

4. The large-area, large-range, six-dimensional force automated calibration device according to claim 3, characterized in that, The upper frame (2-4), the platform (2-1), and the four columns (2-2) together constitute the main load-bearing frame. The specific connection method is as follows: the upper threaded shaft section of the column (2-2) passes through the third circular mounting hole of the upper frame (2-4) and is connected by a T-nut (2-11), and its lower threaded shaft section passes through the first circular mounting hole of the platform (2-1) and is connected by a T-nut (2-11).

5. The large-area, large-range, six-dimensional force automated calibration device according to claim 4, characterized in that, The lateral loading device (3) has tensile and compressive loading ranges of 200kN and 300kN respectively, enabling the lateral span to be adjusted within the range of 0-280mm.

6. The automated six-dimensional force calibration device with a large area and large range according to claim 5, characterized in that, The lateral loading device (3) includes a lateral base frame (3-1), a lateral adapter plate (3-2), a lateral loading frame (3-3), a lateral flange (3-4), a lateral hydraulic cylinder (3-5), a lateral lifting block (3-6), and a lateral worm gear mechanism (3-7); specifically: The lateral base frame (3-1) includes a base plate and three vertical plates on the base plate; The lateral support block (3-6) is a rectangular hard rubber block with a semi-circular groove; The lateral adapter plate (3-2) is a plate with a T-shaped groove on its upper surface. The lateral adapter plate (3-2) is fixedly connected to the upper surface of the lateral base frame (3-1). The lateral loading frame (3-3) is a structure consisting of a base plate and three vertical plates surrounding an opening on one side. A large vertical groove is opened in the center of the front vertical plate, and four small vertical grooves are opened around the large vertical groove. The lateral loading frame (3-3) is connected to the lateral adapter plate (3-2) to support the horizontal position adjustment of the lateral loading frame (3-3). The lateral worm gear mechanism (3-7) is fixedly connected to the base plate of the lateral loading frame (3-3) and is surrounded in the center by its three vertical plates. The worm flange of the lateral worm gear mechanism (3-7) is fixedly connected to the lateral lifting block (3-6). The semi-circular groove of the lateral lifting block (3-6) is matched with the outer diameter of the cylinder of the lateral hydraulic cylinder (3-5). The lateral hydraulic cylinder (3-5) is a bidirectional hydraulic cylinder. Its cylinder body flange and lateral flange (3-4) are located on the inner and outer sides of the front vertical plate of the lateral loading frame (3-3) and are fixedly connected. When the cylinder body flange bolts of the lateral hydraulic cylinder (3-5) are loosened, the vertical position of the lateral hydraulic cylinder (3-5) can be adjusted by changing the worm extension through the lateral worm gear mechanism (3-7). When the lateral hydraulic cylinder (3-5) reaches the appropriate position, the cylinder body flange bolts of the lateral hydraulic cylinder (3-5) are tightened, and the six-dimensional force of the variable loading point is stably calibrated in conjunction with the main loading.

7. The large-area, large-range, six-dimensional force automated calibration device according to claim 6, characterized in that, The vertical plates of the lateral base frame (3-1) and the vertical plates on both sides of the lateral loading frame (3-3) have weight reduction holes.

8. The large-area, large-range, six-dimensional force automated calibration device according to claim 7, characterized in that, The hydraulic control system (4) includes a high-pressure pump station, a proportional relief valve, a multi-channel electromagnetic directional valve, a precision pressure sensor, and an oil tank. The hydraulic control system (4) is fixedly connected to the base (1) and is used to control the pressure and movement of the main hydraulic cylinder (2-9) and the lateral hydraulic cylinder (3-5). The hydraulic control system (4) adjusts the output force of each hydraulic cylinder to achieve synchronous, stepped, or alternating loading of the main and lateral loads, thereby providing a stable power source.

9. The automated six-dimensional force calibration device with a large area and large range according to claim 1, characterized in that, The upper surface of the base (1) is precision milled, with a surface roughness controlled at Ra1.6 and a flatness controlled at 0.

05.

10. A method for automated calibration of six-dimensional forces over a large area and a large range, characterized in that, The implementation of a large-area, large-range, six-dimensional force automated calibration device based on any one of claims 1-9 includes the following steps: Step 1: Preprocess the force measuring instrument (6) to be calibrated; Step 2: Adjust the position of the hydraulic cylinder on the calibration platform; A spatial rectangular coordinate system is established with the countersunk hole at the center of the second adapter plate (2-12) as the origin O. The calibration platform hydraulic cylinders include one main hydraulic cylinder (2-9) and three lateral hydraulic cylinders (3-5). The three lateral hydraulic cylinders (3-5) include the first lateral hydraulic cylinder (3-5-1), the second lateral hydraulic cylinder (3-5-2), and the third lateral hydraulic cylinder (3-5-3). The second lateral hydraulic cylinder (3-5-2) and the third lateral hydraulic cylinder (3-5-3) are located on both sides of the first lateral hydraulic cylinder (3-5-1), and the three form a triangular arrangement. If only the unidirectional force non-variable loading point calibration in the X, Y, and Z directions is required, it is not necessary to move the position of the hydraulic cylinders. Otherwise, the position of the hydraulic cylinders needs to be manually adjusted. When performing Mz torque calibration, adjust the relative horizontal position of the second lateral hydraulic cylinder (3-5-2) and the third lateral hydraulic cylinder (3-5-3), loosen the bolts connecting the lateral loading device (3) and the base (1), move them to the X+ and X- directions respectively, apply pre-tightening force to the bolts according to the standard, and coordinate with the movement of the lateral loading frame (3-3) on the lateral adapter plate (3-2) to reach the preset position; When performing My / Mx calibration, adjust the relative vertical positions of the second lateral hydraulic cylinder (3-5-2) and the third lateral hydraulic cylinder (3-5-3), loosen the bolts connecting the lateral flange (3-4) to the second lateral hydraulic cylinder (3-5-2) and the third lateral hydraulic cylinder (3-5-3), rotate the handwheel of the lateral worm gear mechanism (3-7) to control the lifting and lowering of the second lateral hydraulic cylinder (3-5-2) and the third lateral hydraulic cylinder (3-5-3), and when the second lateral hydraulic cylinder (3-5-2) and the third lateral hydraulic cylinder (3-5-3) reach the preset position, reconnect the lateral flange (3-4) to the second lateral hydraulic cylinder (3-5-2) and the third lateral hydraulic cylinder (3-5-3) with bolts to fix the position of the hydraulic cylinders; Step 3: Calibrate the force gauge (6); Step 3.1, Installation of the force measuring instrument (6); Connect the force gauge (6) to the second adapter plate (2-12) to ensure that the position of the force gauge (6) does not slip during the calibration process, and that its lower surface is tightly connected to the second adapter plate (2-12); connect the calibration block (5) to the force gauge (6), and ensure that the calibration block (5) is located at the center of the force gauge (6) during the connection process; Step 3.2, set the calibration scheme; The use of the calibration platform requires the design of a complete calibration scheme. According to the range of the force measuring instrument (6), the corresponding loading curve is selected, and the upper and lower limit force values, number of steps, holding time and hydraulic cylinder action time step are set according to the step loading method to obtain the calibration scheme. Step 3.3, Calibration operation of force measuring instrument (6); Based on the calibration scheme set in step 3.2, the output of the force measuring instrument (6) is collected synchronously to complete the automatic calibration action: after the loading starts, the hydraulic control system (4) judges whether the loading force value is reached. If the loading force value is reached, pressure is maintained and it is judged whether the pressure maintenance time is reached. If the pressure maintenance time is reached, the loading of the next time step is carried out. It continues to judge whether all time steps are completed. If all time steps are completed, the loading action ends.

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