A loading mechanism for dynamic calibration of a six-dimensional force sensor

Abstract

The application discloses a kind of six-dimensional force sensor dynamic calibration with loading mechanism, it is related to a kind of measuring equipment, including installation disc, the bottom of installation disc is equipped with the six-dimensional force sensor to be measured;Four cantilever beams are arranged on the outer edge of installation disc around its axis, one adapter beam is respectively arranged between adjacent two cantilever beams, installation disc, cantilever beam and adapter beam constitute integral A;Still including integral B, its composition includes counterweight ring and four square columns;One square column is connected to each adapter beam, and the bottom end of each square column is respectively connected with counterweight ring;Integral A and integral B constitute integral C, and the center of gravity of integral C coincides with the coordinate zero point of the six-dimensional force sensor to be measured;Two force application cavities A are formed in each square column, and one force application cavity B is formed in each cantilever beam.The application can eliminate the influence of zero point deviation and inertia effect, effectively improve the precision of six-dimensional force sensor dynamic calibration.

Description

Technical Field

[0001] This invention relates to a measuring device, and more particularly to a loading mechanism for dynamic calibration of a six-dimensional force sensor. Background Technology

[0002] A six-dimensional force sensor is a sensor capable of completely measuring forces and torques in six degrees of freedom in a Cartesian coordinate system. It is widely used in manufacturing, aerospace, and biomedical fields. In recent years, with the continuous development of six-dimensional force sensors in high-precision and high-dynamic applications, the performance requirements for these sensors have become increasingly stringent.

[0003] Sensor calibration is a crucial method for verifying, calibrating, and ensuring the measurement accuracy of sensors. The calibration system for a six-dimensional force sensor mainly consists of a force-applying device, a loading mechanism, and a fixing frame. The force-applying device generates a precise reference force, which is then converted into the six degrees of freedom forces and torques of the sensor under test by the loading mechanism. This establishes a precise relationship between the forces and torques of the sensor and its output signal. The loading mechanism, as the core component of the calibration system, has a crucial impact on the complexity of the calibration device, the flexibility of the calibration process, and the accuracy of the calibration results.

[0004] To facilitate the conversion of reference force into six-degree-of-freedom force and torque, the loading mechanism often requires a specialized design. Patents CN109580089B and CN108731875B disclose a six-dimensional force sensor calibration device using a circular loading mechanism, while patents CN114112186A and CN113899486A disclose a cross-shaped loading mechanism. These calibration devices can flexibly apply six-degree-of-freedom static force and torque to the six-dimensional force sensor under test via the loading mechanism. For calibration requirements in dynamic applications, patents CN113340526B, CN111579152A, and CN110411656A disclose a dynamic calibration device for six-dimensional force sensors, which utilizes cross-shaped and square columnar loading mechanisms to calibrate the dynamic characteristics of the six-dimensional force sensor under test using step-type and pulse-type dynamic reference forces.

[0005] While the existing loading mechanism is ingeniously designed, it suffers from the following problems in practical applications:

[0006] 1) The force application device has a perpendicular deviation between the force application direction of the loading mechanism and the coordinate zero point of the six-dimensional force sensor under test. This causes the reference force in some directions to couple out additional parasitic torque under the action of the lever arm, affecting the accuracy of static and dynamic calibration. 2) The influence of the inertia of the loading mechanism itself is not considered. The center of gravity of the loading mechanism does not coincide with the coordinate zero point of the six-dimensional force sensor. The dynamic reference force will generate additional dynamic torque under the action of inertia, affecting the accuracy of dynamic calibration.

[0007] In summary, the loading mechanism used in existing six-dimensional force sensor dynamic calibration devices does not consider the impact of zero-point deviation, inertia, and other factors on dynamic calibration, which will greatly reduce the accuracy of dynamic calibration in practical applications. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a loading mechanism for calibrating a six-dimensional force sensor. This mechanism ensures that the force application direction of the loading mechanism coincides with the coordinate zero point of the six-dimensional force sensor under test, and that the center of gravity of the loading mechanism itself coincides with the coordinate zero point of the six-dimensional force sensor under test. This eliminates the influence of zero-point deviation and inertia on dynamic calibration. At the same time, the loading mechanism adopts a symmetrical structural design and force application method, which improves the reliability of dynamic calibration under dynamic reciprocating force and torque.

[0009] This invention is achieved through the following technical solution:

[0010] A loading mechanism for dynamic calibration of a six-dimensional force sensor includes a horizontally positioned mounting disk. A six-dimensional force sensor to be measured is coaxially distributed on the bottom of the mounting disk. Four cantilever beams are evenly mounted around the outer edge of the mounting disk, with a connecting beam fixedly connected to the mounting disk between each adjacent cantilever beam. The connecting beams on both sides of each cantilever beam are symmetrically arranged about its axis, and the axis of each cantilever beam coincides with the radial direction of the mounting disk. The mounting disk, the four cantilever beams, and the four connecting beams constitute a whole A. A whole B is positioned directly below whole A, and whole B consists of a counterweight ring and four square columns. Each connecting beam has a square column detachably connected to its outer end. One of the two diagonals in the cross-section of the column coincides with the radial direction of the mounting disk. The bottom end of each square column is detachably connected to a counterweight ring located directly below the mounting disk and coaxially distributed with the mounting disk. The whole A and the whole B constitute the whole C. The center of gravity of the whole C coincides with the coordinate zero point of the six-dimensional force sensor to be measured. Each square column has a force-applying recess A on each of its two side walls away from the axis of the mounting disk. The two force-applying recesses A on the same square column are symmetrically arranged about the diagonal between the two sides in the cross-section of the square column. The coordinate zero point and all the force-applying recesses A are on the same horizontal plane. Each cantilever beam has a force-applying recess B on the top of its outer end. The two force-applying recesses B on both sides of each transition beam are symmetrically arranged about its axis.

[0011] Furthermore, the six-dimensional force sensor under test and the whole B constitute component A. Component A consists of multiple components, and the models of the six-dimensional force sensors under test in different components A are different. Within the same component A, the center of gravity of the whole C formed by the whole A and the whole B coincides with the coordinate zero point of the six-dimensional force sensor under test in component A.

[0012] Furthermore, the mounting disc is specifically a ring structure.

[0013] The present invention has the following advantages over the prior art:

[0014] (1) The force application device coincides with the coordinate zero point of the six-dimensional force sensor under test in the direction of the force application mechanism. It can generate six degrees of freedom force and torque independently. The reference force will not couple out additional parasitic torque, effectively avoiding the influence of parasitic torque on calibration accuracy.

[0015] (2) Considering the influence of the inertia of the loading mechanism itself, the center of gravity of the loading mechanism coincides with the coordinate zero point of the six-dimensional force sensor to be measured. The dynamic reference force will not generate additional dynamic torque under the action of inertia, which effectively improves the accuracy of dynamic calibration.

[0016] (3) The loading mechanism adopts a symmetrical design. The forces and torques of the six degrees of freedom are converted from symmetrical reference forces. Under the action of reciprocating dynamic forces and torques, the force of the six-dimensional force sensor under test is balanced, which improves the reliability of dynamic calibration. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the loading mechanism for calibrating a six-dimensional force sensor provided in Embodiment 1;

[0018] Figure 2 This is a schematic diagram of the assembly of a loading mechanism for calibrating a six-dimensional force sensor, the six-dimensional force sensor under test, and its fixed base, provided in Example 1.

[0019] Figure 3 This is a schematic diagram of a loading mechanism for calibrating a six-dimensional force sensor, which converts the reference force of the force application device into the dynamic force of the six-dimensional force sensor on the X and Y axes.

[0020] Figure 4 This is a schematic diagram of a loading mechanism for calibrating a six-dimensional force sensor, which converts the reference force of the force application device into the dynamic force of the six-dimensional force sensor on the Z-axis. (Example 1)

[0021] Figure 5 This is a schematic diagram of a loading mechanism for calibrating a six-dimensional force sensor, which converts the reference force of the force application device into the dynamic torque of the six-dimensional force sensor on the X and Y axes.

[0022] Figure 6 Example 1 provides a schematic diagram of a loading mechanism for calibrating a six-dimensional force sensor, which converts the reference force of the force application device into the dynamic torque of the six-dimensional force sensor on the Z-axis.

[0023] In the diagram: 1. Mounting disc; 2. Six-dimensional force sensor to be measured; 3. Cantilever beam; 4. Adapter beam; 5. Square column; 6. Counterweight ring; 7. Force application socket A; 8. Force application socket B; 9. Force application device; 10. Fixed base. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have an intervening component. When a component is considered "connected to" another component, it can be directly connected to the other component or may have an intervening component. When a component is considered "set on" another component, it can be directly set on the other component or may have an intervening component. The terms "vertical," "horizontal," and similar expressions used in this document are for illustrative purposes only.

[0026] Example 1

[0027] Combined with appendix Figure 1 This embodiment provides a loading mechanism for calibrating a six-dimensional force sensor, comprising an integral A, which includes a mounting disk 1, four cantilever beams 3, and four transition beams 4. The four cantilever beams 3 are evenly arranged on the outer side of the mounting disk 1 around its axis. The end of each cantilever beam 3 facing the mounting disk 1 is fixedly connected to the mounting disk 1. At the same time, a transition beam 4 is provided between each two adjacent cantilever beams 3, and the end of each transition beam 4 facing the mounting disk 1 is fixedly connected to the mounting disk 1. The cantilever beams 3, transition beams 4, and mounting disk 1 can be manufactured as a single structure or separately manufactured and then welded together. In this embodiment, they are a single structure.

[0028] In the whole A, the axis of each cantilever beam 3 and the axis of each transition beam 4 are distributed radially along the mounting disk 1. That is, the axis of each beam coincides with the radial direction of the mounting disk 1. The included angle between the axes of adjacent cantilever beams 3 is 90 degrees, the included angle between the axes of adjacent transition beams 4 is also 90 degrees, and the included angle between the axes of adjacent transition beams 4 and cantilever beams 3 is 45 degrees. That is, the four cantilever beams 3 and the four transition beams 4 are arranged in a cross pattern on the outer edge of the mounting disk 1.

[0029] Secondly, below the overall A, there is an overall B. The overall B consists of a counterweight ring 6 and four square columns 5. The cross-section of the square columns 5 is square. Each transition beam 4 is detachably connected to a square column 5 at the end opposite to the mounting disk 1. The bottom end of each square column 5 is detachably connected to the top of the counterweight ring 6. In this embodiment, the detachable connection is specifically made by using connecting bolts (not shown in the figure). The counterweight ring 6 is coaxially distributed with the mounting disk 1.

[0030] Secondly, a force-applying recess B8 is provided on the top of the end of each cantilever beam 3 away from the mounting disc 1, and a force-applying recess A7 is provided on each of the two adjacent vertical sidewalls of the four vertical sidewalls in each square column 5. The two force-applying recesses A7 are symmetrically arranged about the diagonal between the two diagonals in the cross-section of the corresponding square column 5.

[0031] That is, the whole C, which is composed of whole A and whole B, serves as the loading mechanism for the dynamic calibration of the six-dimensional force sensor.

[0032] When the above structure is assembled, the two force-applying dimples A7 on each square column 5 are located on the side away from the mounting disk 1, and at this time, the diagonal between the two corresponding force-applying dimples A7 in the cross-section of each square column 5 coincides with the radial direction of the mounting disk 1.

[0033] When calibrating the six-dimensional force sensor 2 to be tested, the six-dimensional force sensor 2 is mounted on the bottom of the mounting disk 1 (in this embodiment, multiple mounting holes are evenly opened on the mounting disk 1, so that the top of the six-dimensional force sensor 2 to be tested is suspended below the mounting disk 1 through the multiple mounting holes). Then, the bottom of the six-dimensional force sensor 2 to be tested is mounted on the horizontal fixed base 10 to complete the assembly of the equipment (e.g., Figure 2 Then, force can be applied to the force application socket A or B to calibrate the six-dimensional force sensor 2 to be tested.

[0034] Specifically, when the equipment is assembled, the zero point of the six-dimensional force sensor 2 to be tested coincides with the center of gravity of the whole C, and all the force-applying dimples B8 are coplanar and the plane coincides with the zero point.

[0035] like Figure 2 When the six-dimensional force sensor 2 to be tested is installed and assembled with the corresponding whole C, the axes of the two cantilever beams 3 at the front and rear are parallel to the Y-axis, and the axes of the two cantilever beams 3 on the left and right are parallel to the X-axis. The whole equipment is set horizontally, that is, the axis of the six-dimensional force sensor 2 to be tested is parallel to the Z-axis. At this time, the zero point of the coordinates of the six-dimensional force sensor 2 to be tested coincides with the center of gravity of the whole C.

[0036] In particular, in order to facilitate the calibration of various models of the six-dimensional force sensor 2 under test, in this embodiment, the six-dimensional force sensor 2 under test and the whole B constitute a component A. There are multiple components A, and the models of the six-dimensional force sensors 2 under test in different components A are different. Within the same component A, the center of gravity of the whole C composed of the whole A and the whole B coincides with the coordinate zero point of the six-dimensional force sensor 2 under test in that component A.

[0037] That is, each six-dimensional force sensor 2 to be tested corresponds to an integral B, which is combined with the common integral A to achieve the purpose of coinciding the center of gravity with the zero point of the coordinate, thereby improving the calibration range; that is, the aforementioned purpose is achieved by combining different square columns 5 with counterweight rings 6.

[0038] In particular, in this embodiment, the mounting disk 1 has a ring structure, which can reduce the overall weight of the equipment and facilitate the installation of the equipment.

[0039] In particular, in this embodiment, the force-applying sockets A and B have the same structure. They are designed to provide a force-applying point for the force-applying device 9. Their structure is designed to establish a connection with the force-applying device 9 so that the force-applying device 9 can apply a pushing or pulling force to it, such as a threaded hole structure.

[0040] Example 2

[0041] like Figure 3 As shown, taking the X-axis as an example, this illustrates the process by which the loading mechanism in Embodiment 1 converts the reference force of the force-applying device 9 into a dynamic force applied to the six-dimensional force sensor 2 under test in the X and Y axis directions. The four force-applying devices 9 act on force-applying sockets A7 on the sidewalls perpendicular to the X-axis direction of the four square columns 5. The direction of the applied force is indicated by the arrows representing the reference forces in the four force-applying devices 9. Specifically, the two force-applying devices 9 on the right side of the diagram apply a tensile force F to the force-applying socket A7, while the two force-applying devices 9 on the left side apply a pushing force F to their respective force-applying sockets A7. Thus, the six-dimensional force sensor 2 under test experiences a positive X-axis force 4F, and vice versa. When the force-applying devices 9 apply the dynamic reference force in the above manner, the six-dimensional force sensor 2 under test will be subjected to a dynamic force along the X-axis, while the forces and torques in other directions are zero. When the four force-applying devices 9 act on the force-applying sockets A7 on the side walls perpendicular to the Y-axis in the outer vertical wall of the four square columns 5 respectively, and apply the dynamic reference force in the manner described above, the six-dimensional force sensor 2 to be measured will be subjected to the dynamic reference force in the Y-axis direction.

[0042] Example 3

[0043] like Figure 4The diagram illustrates the process by which the loading mechanism of Embodiment 1 converts the reference force of the force-applying device 9 into a dynamic force applied to the six-dimensional force sensor 2 along the Z-axis. The four force-applying devices 9 act perpendicularly on the four force-applying sockets B8 corresponding to the four cantilever beams 3. The direction of the applied force is indicated by the arrows representing the reference forces in the four force-applying devices 9. That is, each of the four force-applying devices 9 applies a tensile force F to its corresponding force-applying socket B8, resulting in a tensile force 4F in the positive Z-axis direction for the six-dimensional force sensor 2. Conversely, a force in the opposite Z-axis direction can be applied to the six-dimensional force sensor 2. When the force-applying device 9 applies the dynamic force along the Z-axis in the manner described above, the six-dimensional force sensor 2 will be subjected to the dynamic force along the Z-axis, while the forces and torques in other directions are zero.

[0044] Example 4

[0045] like Figure 5 As shown, the process of the loading mechanism in Embodiment 1 converting the reference force of the force application device 9 into the dynamic torque applied on the X and Y axes by the six-dimensional force sensor 2 to be measured is illustrated. The front and rear force application devices 9 apply the reference torque on the X axis, and the left and right force application devices 9 apply the reference torque on the Y axis.

[0046] When the reference torque is the X-axis torque of the six-dimensional force sensor 2 under test, the two force-applying devices 9 act perpendicularly on the corresponding force-applying sockets B8 on the cantilever beam 3. The direction of the applied force is indicated by the reference force arrow in the force-applying device 9. That is, the rear force-applying device 9 applies a pressure against the Z-axis to the corresponding force-applying socket B8, and the front force-applying device 9 applies a tension along the Z-axis to the force-applying socket B8 below it. Then, the six-dimensional force sensor 2 under test is subjected to a torque along the X-axis. If the two force-applying devices 9 apply a dynamic force in the X-axis direction in the manner described above, the six-dimensional force sensor 2 under test will be subjected to a dynamic force along the X-axis, while the force and torque in other directions will be zero.

[0047] When the reference torque is the Y-axis torque of the six-dimensional force sensor 2 under test, Figure 5 The two force-applying devices 9 on the left and right sides act perpendicularly on the corresponding force-applying sockets B8 on the cantilever beam 3. The direction of the applied force is indicated by the reference force arrows on the two force-applying devices 9. That is, the force-applying device 9 on the right side applies a pressure against the Z-axis to the corresponding force-applying socket B8, and the force-applying device 9 on the left side applies a tension along the Z-axis to the corresponding force-applying socket B8 below it. Then, the six-dimensional force sensor 2 under test is subjected to a torque along the Y-axis. If the two force-applying devices 9 apply a dynamic force along the Y-axis in the manner described above, the six-dimensional force sensor 2 under test will be subjected to a dynamic force along the Y-axis, while the force and torque in other directions will be zero.

[0048] Example 5

[0049] like Figure 6The diagram illustrates the process by which the loading mechanism in Embodiment 1 converts the reference force of the force-applying device 9 into the dynamic torque on the Z-axis of the six-dimensional force sensor 2 under test. The force-applying device 9 on the rear right side acts on the force-applying recess A7 on the rear side wall of the corresponding square column 5, the force-applying device 9 on the front left side acts on the force-applying recess A7 on the front side wall of the corresponding square column 5, the force-applying device 9 on the front right side acts on the force-applying recess A7 on the right side wall of the corresponding square column 5, and the force-applying device 9 on the rear left side acts on the force-applying recess A7 on the left side wall of the corresponding square column 5. The force arrows in the front left and rear right force application devices 9 indicate the direction of the applied force. Specifically, the rear right force application device 9 applies a reverse Y-axis thrust to the corresponding force application socket A7, and the front left force application device 9 applies a Y-axis thrust to the corresponding force application socket A7. The six-dimensional force sensor 2 under test experiences a torque M along the Z-axis. Similarly, the force arrows in the front right and rear left force application devices 9 indicate the direction of the applied force. Specifically, the front right force application device 9 applies a reverse X-axis thrust to the corresponding force application socket A7, and the rear left force application device 9 applies an X-axis thrust to the corresponding force application socket A7. The six-dimensional force sensor 2 under test experiences a torque M along the Z-axis. In other words, under the combined action of the four force application devices 9, the six-dimensional force sensor 2 under test experiences a torque 2M along the Z-axis. If the four force-applying devices 9 apply dynamic force in the manner described above, the six-dimensional force sensor 2 to be measured will be subjected to dynamic force along the Z-axis, while the force and torque in other directions will be zero.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A loading mechanism for dynamic calibration of a six-dimensional force sensor, comprising a horizontally arranged mounting disk, characterized in that, A six-dimensional force sensor is coaxially distributed at the bottom of the mounting disk. Four cantilever beams are evenly connected around the outer edge of the mounting disk, with the axis of each cantilever beam coinciding with the radial direction of the mounting disk. A transition beam, fixedly connected to the mounting disk, is provided between each two adjacent cantilever beams. The transition beams on both sides of each cantilever beam are symmetrically arranged about its axis. The mounting disk, the four cantilever beams, and the four transition beams constitute a whole A. A whole B is located directly below whole A. Whole B consists of four square columns and a counterweight ring. A square column is detachably connected to the outer end of each transition beam. One of the two diagonals in the cross-section of each square column coincides with the radial direction of the mounting disk. The radial surfaces of the mounting discs coincide, and the bottom of each square column is detachably connected to a counterweight ring located directly below the mounting disc and coaxially distributed with it. Components A and B constitute component C, whose center of gravity coincides with the zero point of the six-dimensional force sensor under test. Each square column has a force-applying recess A on each of its two side walls facing away from the axis of the mounting disc. Two force-applying recesses A on the same square column are symmetrically arranged about the diagonal between the two sides of the column's cross-section. All force-applying recesses A and the zero point of the coordinate system are on the same horizontal plane. Each cantilever beam has a force-applying recess B on its outer top end, and two force-applying recesses B on each side of each transition beam are symmetrically arranged about its axis.

2. The loading mechanism for dynamic calibration of a six-dimensional force sensor according to claim 1, characterized in that, The six-dimensional force sensor under test and the whole C constitute component A. Component A consists of multiple components, and the models of the six-dimensional force sensors under test in different components A are different. Within the same component A, the center of gravity of the whole C, which is composed of whole A and whole B, coincides with the coordinate zero point of the six-dimensional force sensor under test in component A.

3. The loading mechanism for dynamic calibration of a six-dimensional force sensor according to claim 2, characterized in that, The mounting disc is specifically a ring-shaped structure.

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