Multi-dimensional force sensor calibration device and calibration method thereof

Abstract

The invention relates to the technical field of six-dimensional force / torque sensors, and discloses a multi-dimensional force sensor calibration device and a calibration method thereof.The multi-dimensional force sensor calibration device comprises a workbench, a fixing assembly and three force vector control mechanisms; the fixing assembly comprises a first fixing piece and a second fixing piece, and the second fixing piece comprises a fixing part and three connecting shafts; the three force vector control mechanisms are distributed around the fixing assembly, and one force vector control mechanism is correspondingly connected with one connecting shaft; the force vector control mechanism comprises a connecting piece, a stay wire, a tension loading assembly and an angle adjusting assembly; according to the multi-dimensional force sensor calibration device provided by the invention, the three force vector control mechanisms are correspondingly connected with the three connecting parts of the second fixing piece respectively, so that different loads borne by a six-dimensional force / torque sensor in practical application can be simulated, and calibration of the six-dimensional force / torque sensor under different measuring ranges can be realized; the method is simple in operation process, high in calibration efficiency, high in flexibility and high in universality.

Description

Technical Field

[0001] This invention relates to the field of six-dimensional force / torque sensor technology, and in particular to a multi-dimensional force sensor calibration device and calibration method thereof. Background Technology

[0002] In modern industry and scientific research, six-dimensional force / torque sensors, as high-precision sensors capable of simultaneously detecting forces and torques in three directions, play a crucial role. They are widely used in many scenarios with extremely high requirements for accurate force and torque sensing, such as robot operation, precision measurement, and aerospace.

[0003] In the research and development and production of six-dimensional force / torque sensors, calibration is an indispensable and crucial step. Based on the method of applying force or torque during calibration, calibration methods are mainly divided into two categories: The first type of calibration method applies orthogonal force and torque independently to each axis. Common implementation methods include utilizing the pulley-weight principle, generating force by suspending a known weight on each axis; or connecting the developed sensor in series with a commercial six-axis sensor, using a mechanical device to apply force and torque to each axis. However, the first type of calibration method has significant drawbacks: it is difficult to effectively solve the inter-axis crosstalk problem, and the operation process is cumbersome, requiring multiple repetitions. The first type of calibration method results in low calibration efficiency. The second type of calibration method applies force and torque in any direction. This can be achieved by using a fixture to connect the developed sensor in series with a commercial six-axis sensor and manually or automatically apply external force in random directions. Alternatively, the developed sensor can be combined with weights attached to the robot's end effector, and the force and torque can be derived based on the kinematic position of the end effector. However, this method also faces difficulties. Six-dimensional joint loading detection or calibration equipment is not only costly, but also requires customized design for sensors with different ranges, resulting in low versatility. Furthermore, it involves the integration of multiple disciplines and multiple high-precision technologies, making it technically challenging. Summary of the Invention

[0004] Aimed at at least solving one of the technical problems existing in the prior art, the present invention aims to provide a multidimensional force sensor calibration device and calibration method thereof, wherein the multidimensional force sensor calibration device has a simple operation process, high calibration efficiency, high flexibility and high versatility.

[0005] To achieve the above objectives, the present invention provides a multi-dimensional force sensor calibration device for calibrating a six-dimensional force / torque sensor, comprising a worktable, a fixing component, and three force vector control mechanisms.

[0006] The fixing assembly includes a first fixing member and a second fixing member. The first fixing member is fixedly connected to the worktable and used to fix it to the bottom of the six-dimensional force / torque sensor. The second fixing member includes a fixing part and three connecting shafts. The fixing part is used to fix it to the top of the six-dimensional force / torque sensor. One end of each connecting shaft is fixedly connected to the outer wall of the fixing part. The three connecting shafts are distributed around the center of the fixing part and have a first central axis. Three force vector control mechanisms are distributed around the fixing assembly, and each force vector control mechanism is connected to one connecting shaft. Each force vector control mechanism includes a connector, a pull wire, a tension loading assembly, and an angle adjustment assembly. The connector is rotatably connected to the connecting shaft. One end of the pull wire is fixedly connected to the connector and the other end is fixedly connected to the tension loading assembly. The angle adjustment assembly is located between the tension loading assembly and the fixing assembly. The angle adjustment assembly is connected to the pull wire and can drive the connector to rotate around the first central axis through the pull wire.

[0007] In some embodiments, the first central axes of the three connecting shafts are located on the same plane, and the included angle formed by the intersection of the first central axes of any two connecting shafts is 120°.

[0008] In some embodiments, the tension loading assembly includes a first drive motor and a roller, the roller being sleeved and fixed on the output shaft of the first drive motor, and one end of the pull wire being fixedly connected to the roller.

[0009] In some embodiments, the angle adjustment assembly includes at least one guide wheel that contacts the pull wire and is capable of adjusting the extension direction of the pull wire by changing its spatial orientation, thereby driving the connector to rotate about the first central axis.

[0010] In some embodiments, the angle adjustment assembly includes a second drive motor, a drive wheel, a transmission belt, a support member, a driven wheel, a mounting member, and a pulley block; the drive wheel is sleeved and fixed on the output shaft of the second drive motor, the support member is fixedly connected to the worktable, the driven wheel has a second central axis, the driven wheel has a central hole, the pull wire passes through the central hole, the driven wheel is rotatably connected to the support member, the drive wheel is driven by the transmission belt and the driven wheel and can drive the driven wheel to rotate around the second central axis, the mounting member is fixedly connected to the driven wheel, the pulley block is connected to the mounting member and located between the driven wheel and the fixed assembly, and the pull wire is wound around the pulley block.

[0011] In some embodiments, in the correspondingly connected force vector control mechanism and the connecting shaft, the second central axis of the force vector control mechanism coincides with the first central axis of the connecting shaft.

[0012] In some embodiments, the pulley assembly includes a first pulley and a second pulley, the first pulley being connected to the mounting member and located between the driven pulley and the fixing component, the second pulley being connected to the mounting member and located between the first pulley and the fixing component, the top of the second pulley being higher than the top of the first pulley, and the pull cable being wound from the bottom of the first pulley to the top of the second pulley.

[0013] The present invention also provides a calibration method for the multidimensional force sensor calibration device according to any one of the preceding claims, comprising the following steps: Fixing the six-dimensional force / torque sensor: Fix the bottom of the six-dimensional force / torque sensor to the first fixing member, fix the second fixing member to the six-dimensional force / torque sensor and make the center of the second fixing member coincide with the center of the six-dimensional force / torque sensor; Connection force vector control mechanism: The connecting shaft of the connecting member is rotatably connected to the second fixing member, and the pull wire is fixedly connected to the connecting member; Loading force vector: According to calibration needs, one or more force vector control mechanisms from the three force vector control mechanisms are selected to load the force vector onto the connector; wherein, the tension loading component is used to adjust the magnitude of the force vector, the angle adjustment component is used to adjust the angle of the force vector, and the standard force value of six-dimensional force / torque is obtained based on the known magnitude and angle of the force vector; Comparison with standard force value: The measurement results of the six-dimensional force / torque sensor are compared with the standard force value to calculate the measurement error; if the measurement error exceeds the preset condition, the angle of the force direction of the pull wire is adjusted by the angle adjustment component, and the tension of the pull wire is adjusted by the tension loading component until the measurement error falls within the allowable range; Output calibration results: When the measurement error meets the preset conditions, record the loading parameters of the current force vector. The loading parameters include the magnitude and angle of the force vector, which serve as the calibration reference for the six-dimensional force / torque sensor.

[0014] Compared with the prior art, the multi-dimensional force sensor calibration device provided in this embodiment of the invention has the following advantages: (1) In the force vector control mechanism, the magnitude of the force vector applied to the connecting shaft by the force loading component can be adjusted by pulling the pull wire to adjust the magnitude of the force vector applied to the six-dimensional force / torque sensor. The angle adjustment component can drive the connecting piece to rotate around the first central axis to adjust the angle of the force vector applied to the connecting shaft by the force vector mechanism to adjust the angle of the force vector applied to the six-dimensional force / torque sensor. The standard force value of the six-dimensional force / torque applied to the six-dimensional force / torque sensor can be obtained by using the known magnitude and angle of the force vector applied to the six-dimensional force / torque sensor. The measurement results of the six-dimensional force / torque sensor and the standard force value of the six-dimensional force / torque applied to the six-dimensional force / torque sensor can be obtained by using the measurement results of the six-dimensional force / torque sensor and the standard force value of the six-dimensional force / torque applied to the six-dimensional force / torque sensor. By comparing and adjusting standard force values, the six-dimensional force / torque sensor can be calibrated. Different six-dimensional forces / torques can be obtained by adjusting the magnitude and angle of the force vector using a tension loading component and an angle adjustment component, respectively, thus enabling the calibration of the six-dimensional force / torque sensor at different ranges. Therefore, the method provided by this invention for calibrating a six-dimensional force / torque sensor by adjusting the magnitude and angle of the force vector using connectors, a pull wire, a tension loading component, and an angle adjustment component is simpler to operate and more efficient than existing first-type calibration methods. Compared to existing second-type calibration methods, it reduces equipment complexity and manufacturing costs. This invention can control the generation of six-dimensional forces / torques at different ranges, offering high flexibility and versatility.

[0015] (2) By distributing three force vector control mechanisms around the fixed component and corresponding to the three connecting shafts evenly distributed around the center of the fixed part on the second fixed component, and by coordinating the tension amplitude applied to the tension wire by the tension loading component and the angle of the angle adjustment component driving the connecting part to rotate around the first central axis, the resultant force application point of the three tension wires can be accurately aligned with the measurement center of the six-dimensional force / torque sensor, thereby helping to eliminate inter-axis crosstalk caused by the offset of the force application point; on this basis, either a force vector can be applied in a single direction by any one force vector control mechanism to achieve single-dimensional independent loading, or any two or three force vector control mechanisms can be used to coordinate loading in different directions. This device enables multi-dimensional composite loading, covering the diverse needs of six-dimensional force / torque sensors in practical applications. By adjusting the tension amplitude of the tension cable through the tension loading component and controlling the force vector direction through the angle adjustment component, it can generate six-dimensional force / torque inputs covering different ranges, adapting to various six-dimensional force / torque sensor models without requiring customized equipment for each range. Therefore, the multi-dimensional force sensor calibration device provided by this invention can simulate different loads that a six-dimensional force / torque sensor may experience in practical applications in one go, and can calibrate the six-dimensional force / torque sensor at different ranges in one go, simplifying the operation process and improving calibration efficiency through three force vector control mechanisms. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a multi-dimensional force sensor calibration device provided in an embodiment of the present invention; Figure 2 This is a front view of a multi-dimensional force sensor calibration device provided in an embodiment of the present invention; Figure 3 This is a top view of a multi-dimensional force sensor calibration device provided in an embodiment of the present invention; Figure 4 This is a schematic diagram showing the axial relationship between the second fixing member and the driven wheel provided in an embodiment of the present invention; Figure 5 This is a front view of the fixed assembly equipped with a six-dimensional force / torque sensor provided in an embodiment of the present invention; Figure 6 This is a top view of the second fastener provided in an embodiment of the present invention; Figure 7 This is a partial structural schematic diagram of the force vector control mechanism provided in an embodiment of the present invention; Figure 8 This is a block diagram of a calibration method for a multidimensional force sensor calibration device provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the kinematic model principle of a multi-dimensional force sensor calibration device provided in an embodiment of the present invention; Figure 10 This is a schematic diagram of the kinematic analysis of Fx provided in an embodiment of the present invention.

[0017] In the diagram, 1 represents the workbench; 2. Fixing component; 21. First fixing member; 22. Second fixing member; 221. Fixing part; 222. Connecting shaft; 3. Force vector control mechanism; 31. Connector; 32. Pull cable; 33. Tension loading assembly; 34. Angle adjustment assembly; 331. First drive motor; 332. Roller; 340. Guide wheel; 341. Second drive motor; 342. Driving wheel; 343. Transmission belt; 344. Driven wheel; 345. Mounting component; 346. Pulley block; 347. Support component; 3441. Center hole; 3461. First pulley; 3462. Second pulley; 4. Six-dimensional force / torque sensor; 10. First central axis; 20. Second central axis. Detailed Implementation

[0018] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0019] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0021] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having" and any variations thereof in the description, claims and foregoing drawings of this application are intended to cover non-exclusive inclusion.

[0024] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0025] like Figures 1 to 4 As shown in the figure, a preferred embodiment of the present invention provides a multi-dimensional force sensor calibration device for calibrating a six-dimensional force / torque sensor 4, comprising a worktable 1, a fixing component 2, and three force vector control mechanisms 3.

[0026] The fixing assembly 2 includes a first fixing member 21 and a second fixing member 22. The first fixing member 21 is fixedly connected to the workbench 1 and used to fix it to the bottom of the six-dimensional force / torque sensor 4. The second fixing member 22 includes a fixing part 221 and three connecting shafts 222. The fixing part 221 is used to fix it to the top of the six-dimensional force / torque sensor 4. One end of the connecting shaft 222 is fixedly connected to the outer wall of the fixing part 221. The three connecting shafts 222 are distributed around the center of the fixing part 221, and the connecting shafts 222 have a first central axis 10. Three force vector control mechanisms 3 are arranged around the fixing assembly. The components are distributed as follows: one force vector control mechanism 3 is connected to one connecting shaft 222; the force vector control mechanism 3 includes a connector 31, a pull wire 32, a tension loading component 33, and an angle adjustment component 34. The connector 31 is rotatably connected to the connecting shaft 222. One end of the pull wire 32 is fixedly connected to the connector 31, and the other end is fixedly connected to the tension loading component 33. The angle adjustment component 34 is located between the tension loading component 33 and the fixed component 2. The angle adjustment component 34 is connected to the pull wire 32 and can drive the connector 31 to rotate around the first central axis 10 through the pull wire 32.

[0027] Based on this technical solution, in the force vector control mechanism 3, the magnitude of the force vector applied to the connecting shaft 222 by pulling the pull wire 32 through the tension loading component 33 can be adjusted to adjust the magnitude of the force vector applied to the six-dimensional force / torque sensor 4. The angle adjustment component 34 drives the connecting piece 31 to rotate around the first central axis 10 to adjust the angle of the force vector applied to the connecting shaft 222, thereby adjusting the angle of the force vector applied to the six-dimensional force / torque sensor 4. Using the known magnitude and angle of the force vector applied to the six-dimensional force / torque sensor 4, the standard force value of the six-dimensional force / torque applied to the six-dimensional force / torque sensor 4 can be obtained. By comparing and adjusting the measurement results of the six-dimensional force / torque sensor 4 with the standard force value, the following can be achieved: This invention enables the calibration of a six-dimensional force / torque sensor 4. By using the tension loading component 33 and the angle adjustment component 34 to adjust the magnitude and angle of the force vector, different six-dimensional forces / torques can be obtained, thus enabling the calibration of the six-dimensional force / torque sensor 4 under different ranges. Therefore, the method provided by this invention for calibrating the six-dimensional force / torque sensor 4 by adjusting the magnitude and angle of the force vector through the connector 31, pull wire 32, tension loading component 33, and angle adjustment component 34 is simpler to operate and more efficient than the existing first-type calibration method. Compared with the existing second-type calibration method, it reduces equipment complexity and manufacturing costs. This invention can control the generation of six-dimensional forces / torques in different ranges, offering high flexibility and versatility.

[0028] By distributing three force vector control mechanisms 3 around the fixing component 2 and correspondingly connecting them to three connecting shafts 222 evenly distributed around the center of the fixing part 221 on the second fixing member 22, and by coordinating the adjustment of the tension amplitude applied to the tension wires 32 by the tension loading component 33 and the angle of rotation of the connecting member 31 around the first central axis 10 driven by the angle adjustment component 34, the resultant force application point of the three tension wires 32 can be precisely aligned with the measurement center of the six-dimensional force / torque sensor 4, thereby helping to eliminate inter-axis crosstalk caused by the offset of the force application point. On this basis, either a force vector can be applied in a single direction by any one of the force vector control mechanisms 3 to achieve independent loading in a single dimension, or any two or three force vector control mechanisms can be used to achieve independent loading in a single dimension. The mechanism coordinates loading in different directions to achieve multi-dimensional composite loading, covering the diverse needs of six-dimensional force / torque sensors in practical applications. By adjusting the tension amplitude of the tension cable through the tension loading component and controlling the force vector direction through the angle adjustment component, six-dimensional force / torque inputs covering different ranges can be generated, adapting to various six-dimensional force / torque sensor models without the need for customized equipment for each range. Therefore, the multi-dimensional force sensor calibration device provided by this invention can simulate different loads that a six-dimensional force / torque sensor may experience in practical applications in one go, and can calibrate the six-dimensional force / torque sensor at different ranges in one go, simplifying the operation process and improving calibration efficiency through three force vector control mechanisms.

[0029] It should be noted that the connecting shaft 222 extends radially outward, and its first central axis 10 is perpendicular to the vertical axis passing through the center of the fixing part 221.

[0030] In a preferred embodiment of the present invention, the draw wire 32 is made of a high-modulus, low-creep, non-stretchable material to ensure that its length change is negligible during loading, thereby ensuring high stability and repeatability of the magnitude and direction of the force vector applied to the six-dimensional force / torque sensor 4. Specifically, the draw wire 32 may be selected from one of carbon fiber composite rope, aramid fiber rope, stainless steel wire rope, or titanium alloy wire.

[0031] See Figure 6 The fixing part 221 has a disc-shaped structure, and the center of the fixing part 221 is the center of its circle.

[0032] See Figure 4 and Figure 6 Preferably, the first central axes 10 of the three connecting shafts 222 are located on the same plane, and the angle formed by the intersection of the first central axes 10 of any two connecting shafts 222 is 120°. By locating the first central axes 10 of the three connecting shafts 222 on the same plane with an angle of 120°, the force applied to the six-dimensional force / torque sensor 4 by the three force vector control mechanisms 3 is more balanced, which helps to more accurately convert the three force vectors applied to the six-dimensional force / torque sensor 4 by the three force vector control mechanisms 3 into six-dimensional force / torque, further improving the accuracy of calibration.

[0033] In this embodiment, the first central axis 10 of the three connecting shafts 222 is located on a horizontal plane.

[0034] The tension loading component 33 includes a first drive motor 331 and a roller 332. The roller 332 is sleeved and fixed on the output shaft of the first drive motor 331, and one end of the pull wire 32 is fixedly connected to the roller 332.

[0035] By employing a first drive motor 331 and a roller 332 as the tension loading component 33, the tension of the pull wire 32 can be precisely controlled, thereby accurately adjusting the magnitude of the force applied to the six-dimensional force / torque sensor 4. The speed and torque of the first drive motor 331 can be precisely controlled by the control system. When the motor rotates, it drives the roller 332, which is sleeved and fixed on the first output shaft, to rotate. Since one end of the pull wire 32 is fixed on the roller 332, the rotation of the roller 332 will retract and extend the pull wire 32, thereby adjusting the magnitude of the tension. Compared with the first type of calibration method that relies on gravity loading such as weights, the loading method of the first drive motor 331 and roller 332 provided by this invention can more flexibly and accurately simulate the magnitude of the force under various actual working conditions, improving the accuracy of calibration. Compared with the second type of calibration method that relies on clamps and end effectors, this invention has fewer parts, reducing the complexity of the device. The simple structure of this invention also facilitates installation, debugging, and maintenance, reducing maintenance costs and extending the service life of the multi-dimensional force sensor calibration device.

[0036] See Figure 2 and Figure 3 The angle adjustment component 34 includes at least one guide wheel 340, which is in contact with the pull wire 32 and can adjust the extension direction of the pull wire 32 by changing its own spatial posture, thereby driving the connector 31 to rotate around the first central axis 10.

[0037] By incorporating at least one guide wheel 340 in contact with the pull wire 32 within the angle adjustment assembly, and enabling it to adjust the extension direction of the pull wire 32 by changing its spatial attitude, high-precision, continuous, and stepless adjustment of the force vector direction can be achieved. Specifically, changes in the spatial attitude (such as pitch angle and azimuth angle) of the guide wheel 340 can be directly and stably converted into changes in the direction of the pull wire's action, thereby driving the connector 31 to rotate around the first central axis 10, thus precisely controlling the spatial orientation of the force vector applied to the six-dimensional force / torque sensor 4. Using the guide wheel 340 avoids the clearance error and motion coupling problems inherent in traditional rigid linkage mechanisms. Furthermore, when multiple force vector control mechanisms 3 are adjusted collaboratively, the independent attitude adjustment of the guide wheel 340 allows the point of application of the resultant force of each pull wire 32 to precisely converge at the sensor's measurement center, eliminating additional torque caused by lever arm offset, significantly reducing inter-axis crosstalk, and improving calibration accuracy.

[0038] It should be noted that the guide wheel 340 can be a single pulley or a pulley block composed of multiple pulleys, and its installation position is adjustable. When the spatial attitude (such as pitch angle, azimuth angle) of the guide wheel changes, the extension direction of the pull wire 32 in contact with it changes accordingly, thereby driving the connecting piece 31 to rotate around the first central axis 10 of the connecting shaft 222, so as to achieve precise control of the force vector direction.

[0039] See Figure 2 , Figure 3 and Figure 7 The angle adjustment assembly 34 includes a second drive motor 341, a drive wheel 342, a transmission belt 343, a support 347, a driven wheel 344, a mounting component 345, and a pulley block 346. The driving wheel 342 is sleeved and fixed on the output shaft of the second drive motor 341. The support member 347 is fixedly connected to the worktable 1. The driven wheel 344 has a second central axis 20 and a central hole 3441. The pull wire 32 passes through the central hole 3441. The driven wheel 344 is rotatably connected to the support member 347. The driving wheel 342 is connected to the driven wheel 344 via a transmission belt 343 and can drive the driven wheel 344 to rotate around the second central axis 20 via the transmission belt 343. The mounting member 345 is fixedly connected to the driven wheel 344. The pulley block 346 is connected to the mounting member 345 and is located between the driven wheel 344 and the fixed component 2. The pull wire 32 is wound around the pulley block 346, that is, the guide wheel 340 is the pulley block 346.

[0040] The second drive motor 341, drive wheel 342, transmission belt 343, driven wheel 344, and other components form the angle adjustment assembly 34. The rotation of the driven wheel 344 can be precisely controlled, thereby precisely adjusting the angle of the pull wire 32 and achieving precise control over the direction of the force applied to the six-dimensional force / torque sensor 4. The precise control performance of the second drive motor 341 allows the rotation angle of the drive wheel 342 to be precisely adjusted. The transmission belt 343 drives the driven wheel 344 to rotate stably around the second central axis 20, ensuring the accuracy of the angle change of the pull wire 32 connected to the driven wheel 344. This enables more accurate simulation of the loads on the six-dimensional force / torque sensor 4 in different directions during practical applications, improving the accuracy of the calibration of the six-dimensional force / torque sensor 4.

[0041] The layout of the pulley block 346 can be optimized, making the direction of the pulley block 32 between the driven wheel 344 and the fixed component 2 more reasonable. The pulley block 346 can also change the direction of the pulley block 32, avoiding problems such as interference or tangling of the pulley block 32 during movement, and ensuring the smooth transmission of tension.

[0042] See Figure 6Preferably, in the correspondingly connected force vector control mechanism 3 and connecting shaft 222, the second central axis 20 of the force vector control mechanism 3 and the first central axis 10 of the connecting shaft 222 coincide. By aligning the second central axis 20 of the force vector control mechanism 3 with the first central axis 10 of the connecting shaft 222, it can be ensured that during the adjustment of the tension angle by the force vector control mechanism 3, the tension can be transmitted to the six-dimensional force / torque sensor 4 along an ideal path. This helps reduce force offset or loss caused by axis misalignment, making the force vector applied by the force vector control mechanism 3 to the six-dimensional force / torque sensor 4 more accurate and in line with expectations, thus improving calibration accuracy. Simultaneously, the alignment of the second central axis 20 and the first central axis 10 simplifies the kinematic model of the entire multi-dimensional force sensor calibration device. In terms of control system design and data analysis during calibration, there is no need for complex calculations to compensate for errors caused by axis deviation, allowing engineers to more easily achieve precise control of the force vector control mechanism 3. It also facilitates accurate analysis and processing of calibration data, improving the overall efficiency of calibration work and reducing the technical difficulty of the calibration process.

[0043] In this embodiment, the pulley block 346 includes two pulleys.

[0044] In some other embodiments, the pulley block 346 may also include any number of pulleys, such as three, four, or five, and this is not limited here.

[0045] See Figure 7 The two pulleys are a first pulley 3461 and a second pulley 3462. The first pulley 3461 is connected to the mounting member 345 and is located between the driven wheel 344 and the fixing component 2. The second pulley 3462 is connected to the mounting member 345 and is located between the first pulley 3461 and the fixing component 2. The top of the second pulley 3462 is higher than the top of the first pulley 3461. The pull wire 32 is wound from the bottom of the first pulley 3461 to the top of the second pulley 3462.

[0046] The pulley block 346 employs a first pulley 3461 and a second pulley 3462, along with a specific winding method for the pull wire 32. Specifically, the pull wire 32 winds from the bottom of the first pulley 3461 to the top of the second pulley 3462. This effectively changes the direction of movement of the pull wire 32, making its path within the multi-dimensional force sensor calibration device more reasonable. This avoids interference between the pull wire 32 and other components during movement, ensuring smooth force transmission and guaranteeing the stability of the force vector applied by the force vector control mechanism 3 to the six-dimensional force / torque sensor 4, thereby improving the reliability of the calibration process.

[0047] By combining the two pulleys, the friction between the pull wire 32 and the pulleys can be increased, which helps to control the movement of the pull wire 32 more precisely. When the angle adjustment component 34 is working, the pull wire 32 can respond more accurately to the action of the second drive motor 341. The small rotational changes of the second drive motor 341 can be more accurately converted into changes in the angle of the pull wire 32, thereby achieving more precise adjustment of the direction of the force applied to the six-dimensional force / torque sensor 4, and further improving the accuracy of the multi-dimensional force sensor calibration device.

[0048] See Figure 8 The present invention also provides a calibration method for any of the above-mentioned multidimensional force sensor calibration devices, comprising the following steps: S1, Fix the six-dimensional force / torque sensor 4: Fix the bottom of the six-dimensional force / torque sensor 4 to the first fixing member 21, and fix the second fixing member 22 to the six-dimensional force / torque sensor 4 so that the center of the second fixing member 22 coincides with the center of the six-dimensional force / torque sensor 4; S2, connecting force vector control mechanism 3: the connecting shaft 222 of the connecting piece 31 is rotatably connected to the second fixing piece 22, and the pull wire 32 is fixedly connected to the connecting piece 31; S3, Loading force vector: According to the calibration requirements, select one or more force vector control mechanisms 3 from the three force vector control mechanisms 3 to load the force vector onto the connector 31; wherein, the tension loading component 33 is used to adjust the magnitude of the force vector, and the angle adjustment component 34 is used to adjust the angle of the force vector, and the standard force value of the six-dimensional force / torque is obtained according to the magnitude and angle of the force vector. S4, Comparison with standard force value: Compare the measurement result of the six-dimensional force / torque sensor 4 with the standard force value and calculate the measurement error; if the measurement error exceeds the preset condition, adjust the angle of the pull wire 32 through the angle adjustment component 34 and adjust the tension of the pull wire 32 through the tension loading component 33 until the measurement error falls within the allowable range; S5, Output calibration results: When the measurement error meets the preset conditions, record the loading parameters of the current force vector. The loading parameters include the magnitude and angle of the force vector, which serve as the calibration reference for the six-dimensional force / torque sensor 4.

[0049] It should be noted that the calculation of measurement error and the setting of preset conditions can be referred to the standard GB / T 43199-2023 Robot Multi-dimensional Force / Torque Sensor Testing Specification, which will not be elaborated here.

[0050] In the force vector loading step, the method of single-dimensional independent loading is as follows: select any one force vector control mechanism 3 as the target mechanism, and fix the tension of the pull wires 32 of the other two mechanisms to zero; drive the connector 31 to rotate around the first central axis 10 through the angle adjustment component 34, so that the force direction of the pull wire 32 is aligned with the target axis (such as Fx, Fy or Fz); adjust the tension of the pull wire 32 through the tension loading component 33 so that the force value of the target axis reaches the preset standard (such as 5N, 10N, etc.), and record the tension and angle of the pull wire at this time; In the force vector loading step, the multi-dimensional composite loading method is as follows: select two or three force vector control mechanisms 3 for collaborative loading, and execute them in the following order: S31, the angle of all the pull wires 32 is fixed by the angle adjustment component 34, and the tension of each pull wire is adjusted by the tension loading component 33, so that the point of application of the resultant force coincides with the measurement center of the six-dimensional force / torque sensor 4; S32, fix the tension amplitude of each pull wire, and adjust the angle of the force direction of the pull wire 32 through the angle adjustment component 34 so that the resultant force direction is consistent with the target six-dimensional force / torque vector direction; S33, according to the preset six-dimensional force / torque calibration matrix (such as Fx=10N, Fy=5N, Fz=15N, Mx=2Nm, etc.), the tension and angle of each tension line are synchronously adjusted through the tension loading component 33 and the angle adjustment component 34 so that the actual loaded six-dimensional force / torque value matches the standard value; See Figures 9 to 10 Six-dimensional force / torque and three perpendicular forces (F) n1 F n2 F n2 ) and three horizontal forces (F s1 F s2 F s3 The relationship is: (1) in , representing six-dimensional force / torque.

[0051] , representing three horizontal forces and three vertical forces.

[0052] (2) Therefore, we can obtain F=K -1 W(3).

[0053] K -1 It can be obtained by matrix inversion, as shown in formula (4): (4) According to formulas (3) and (4), the six-dimensional force can be transformed into three vertical forces and three horizontal forces, and further transformed into three force vectors through formula (5). This means that if the magnitude and angle of the three force vectors are known, all components of the six-dimensional force / torque can be obtained.

[0054] (5) according to Figures 8-9 According to formulas (1) to (5), the multi-dimensional force sensor calibration device provided by the present invention sets up three force vector control mechanisms 3. The force vector control mechanism 3 controls the magnitude of the force vector through the tension loading component 33 and controls the angle of the force vector through the angle adjustment component 34. In the calibration process of the six-dimensional force / torque sensor 4, the magnitude and angle of the three force vectors can be known through the multi-dimensional force sensor calibration device provided by the present invention, so as to obtain all components of the six-dimensional force / torque, and then the standard force value of the six-dimensional force / torque applied to the six-dimensional force / torque sensor 4 by the force vector control mechanism 3 can be obtained. By comparing and adjusting the measurement results of the six-dimensional force / torque sensor 4 in the calibration process with the standard force value, the calibration of the six-dimensional force / torque sensor 4 can be realized.

[0055] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A multi-dimensional force sensor calibration device for calibrating a six-dimensional force / moment sensor (4), characterized by The utility model relates to a six-dimensional force / torque sensor test device, including: a workbench (1); a fixing assembly (2), the fixing assembly (2) includes first fixed part (21) and second fixed part (22), first fixed part (21) is fixedly connected on the workbench (1) and is used for with the bottom of six-dimensional force / torque sensor (4) is fixed, second fixed part (22) includes fixed part (221) and three connecting shafts (222), fixed part (221) is used for with the top of six-dimensional force / torque sensor (4) is fixed, one end of connecting shaft (222) is fixedly connected to the outside wall of fixed part (221), and three connecting shafts (222) are distributed around the center of fixed part (221), and connecting shaft (222) has first central axis (10); three force vector control mechanisms (3), three force vector control mechanisms (3) are distributed around the fixing assembly (2), and one force vector control mechanism (3) is connected with one connecting shaft (222); the force vector control mechanism (3) includes connecting piece (31), guy (32), tension loading assembly (33) and angle adjusting assembly (34), connecting piece (31) is rotatably connected to connecting shaft (222), one end of guy (32) is fixedly connected to connecting piece (31), the other end is fixedly connected to tension loading assembly (33), angle adjusting assembly (34) is located between tension loading assembly (33) and fixing assembly (2), and angle adjusting assembly (34) is connected with guy (32) and can drive connecting piece (31) to rotate around first central axis (10) by guy (32).

2. The multi-dimensional force sensor calibration apparatus of claim 1, wherein, The first central axis (10) of the three connecting shafts (222) is located on the same plane, and the included angle formed by the first central axis (10) of any two connecting shafts (222) is 120 °.

3. The multi-dimensional force sensor calibration apparatus of claim 1, wherein, the tension loading assembly (33) includes a first drive motor (331) and a roller (332), the roller (332) is sleeved and fixed on the output shaft of the first drive motor (331), and one end of the guy (32) is fixedly connected to the roller (332).

4. The multi-dimensional force sensor calibration apparatus of claim 1, wherein, The angle adjusting assembly (34) includes at least one guide wheel (340), the guide wheel (340) is in contact with the guy (32), and the extension direction of the guy (32) can be adjusted by changing the spatial posture of the guide wheel (340), so as to drive the connecting piece (31) to rotate around the first central axis (10).

5. The multi-dimensional force sensor calibration apparatus of claim 1, wherein, the angle adjusting assembly (34) includes a second drive motor (341), a driving wheel (342), a transmission belt (343), a support (347), a driven wheel (344), a mounting (345) and a pulley block (346). The driving wheel (342) is sleeved and fixed on the output shaft of the second driving motor (341), the support (347) is fixedly connected to the workbench (1), the driven wheel (344) has a second center axis (20), the driven wheel (344) is provided with a center hole (3441), the pull wire (32) is arranged in the center hole (3441), the driven wheel (344) is rotatably connected to the support (347), the driving wheel (342) is drivingly connected with the driven wheel (344) through the transmission belt (343) and can drive the driven wheel (344) to rotate around the second center axis (20) through the transmission belt (343), the mounting piece (345) is fixedly connected to the driven wheel (344), the pulley block (346) is connected to the mounting piece (345) and located between the driven wheel (344) and the fixed assembly (2), and the pull wire (32) is arranged around the pulley block (346).

6. The multi-dimensional force sensor calibration apparatus of claim 5, wherein, In the corresponding connecting force vector control mechanism (3) and the connecting shaft (222), the second center axis (20) of the force vector control mechanism (3) and the first center axis (10) of the connecting shaft (222) coincide.

7. The multi-dimensional force sensor calibration apparatus of claim 5, wherein, The pulley block (346) comprises a first pulley (3461) and a second pulley (3462), the first pulley (3461) is connected to the mounting piece (345) and located between the driven wheel (344) and the fixed assembly (2), the second pulley (3462) is connected to the mounting piece (345) and located between the first pulley (3461) and the fixed assembly (2), the top of the second pulley (3462) is higher than the top of the first pulley (3461), and the pull wire (32) is arranged from the bottom of the first pulley (3461) to the top of the second pulley (3462).

8. A calibration method of a multi-dimensional force sensor calibration apparatus according to any one of claims 1 to 7, characterized by, The method comprises the following steps: Fixing the six-dimensional force / torque sensor (4): fixing the bottom of the six-dimensional force / torque sensor (4) to the first fixing piece (21), and fixing the second fixing piece (22) to the six-dimensional force / torque sensor (4) so that the center of the second fixing piece (22) coincides with the center of the six-dimensional force / torque sensor (4); Connecting the force vector control mechanism (3): rotatably connecting the connecting piece (31) to the connecting shaft (222) of the second fixing piece (22), and fixedly connecting the pull wire (32) to the connecting piece (31); Loading force vector: selecting one or more force vector control mechanisms (3) in the three force vector control mechanisms (3) according to the calibration requirement to load force vector on the connecting piece (31); wherein the tension loading assembly (33) is used to adjust the size of the force vector, and the angle adjusting assembly (34) is used to adjust the angle of the force vector, and the standard force value of the six-dimensional force / torque is obtained according to the known size and angle of the force vector; Compared with the standard force value: the measurement results of the six-dimensional force / torque sensor (4) are compared with the standard force value to calculate the measurement error; if the measurement error exceeds the preset condition, the angle of the force application direction of the pull wire (32) is adjusted through the angle adjusting assembly (34), and the tension of the pull wire (32) is adjusted through the tension loading assembly (33) until the measurement error falls within the allowable range; Output calibration results: when the measurement error meets the preset condition, record the current force vector loading parameter, including the size of the force vector and the angle of the force vector, as the calibration reference of the six-dimensional force / torque sensor (4).

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