Force application device for calibration of force sensor

Abstract

The invention relates to the technical field of force sensor calibration, in particular to a force application device for force sensor calibration. Comprising a force transmission sleeve connected with a force sensor; the first spring and the second spring are arranged in the force transmission sleeve in the axis direction and used for generating spring force; the force application rod is used for compressing the first spring or the second spring; the driving mechanism drives the force applying rod to do reciprocating linear motion; and the displacement measurement assembly is used for measuring the moving distance of the force application rod. The force application rod is driven by the driving mechanism to do reciprocating rectilinear motion, so that the force application rod compresses the spring, automatic loading is achieved, continuous force in the positive direction and the negative direction is achieved at the same time, impact generated during force application can be effectively avoided, and the effect of protecting the force sensor is achieved; the moving distance of the force application rod is measured through the stiffness coefficient of the spring and the displacement measuring assembly, the magnitude of the pushing force or the pulling force borne by the force transmission sleeve is calculated, then the force acting on the force sensor is known, and the accuracy of the loading force value is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of force sensor calibration technology, and in particular to a force application device for force sensor calibration. Background Technology

[0002] Force sensors measure force magnitude and have wide applications in production and daily life. Classified by measurement dimension, they can be divided into single-axis force sensors (measuring only one dimension at a time) and multi-axis force sensors (measuring multiple components simultaneously). Regardless of the type, force sensors require precise calibration before leaving the factory to ensure high measurement accuracy in application. Force sensor calibration is the process of applying accurate force according to a coordinate system to establish the correspondence between force and output signal.

[0003] In the calibration process of force sensors, the accuracy of the applied force directly affects the accuracy of the sensor's measurements. Commonly used force application methods include using weights for loading, or using a servo electric cylinder combined with a higher-precision single-axis force sensor for loading. When using weights for loading, there are problems such as discontinuous loading force values ​​and difficulty in achieving automatic loading. When using a servo electric cylinder combined with a higher-precision tension or pressure sensor for loading, the control system is complex, the procurement and maintenance costs of the high-precision tension or pressure sensor are high, and it requires regular testing and calibration. In addition, applying a specified force value requires high control precision.

[0004] Based on the above problems, there is an urgent need to develop a force application device with continuously adjustable force value, high accuracy of applied force value, and support for automated calibration, so as to overcome the shortcomings of existing methods. Summary of the Invention

[0005] The purpose of this invention is to provide a force application device for force sensor calibration, which can solve the problems of discontinuous force value, low application accuracy, and difficulty in achieving automatic loading in the existing force application methods. This invention provides a force application device for calibrating a force sensor, comprising: A force transmission sleeve is used to transmit force to the force sensor to be calibrated. The first spring and the second spring are disposed inside the force transmission sleeve along the axial direction to generate spring force. The force-applying rod has one end located inside the force-transmitting sleeve, used to compress the first spring or the second spring; the other end extends outside the force-transmitting sleeve. A drive mechanism is connected to one end of the force-applying rod that extends outside the force-transmitting sleeve, and is used to drive the force-applying rod to perform reciprocating linear motion. A displacement measuring component is used to measure the distance the force-applying rod moves.

[0006] Furthermore, the end of the force transmission sleeve furthest from the drive mechanism is connected to the measuring end of the force sensor to be calibrated.

[0007] Furthermore, the force-applying rod includes a coaxially arranged disk and a vertical rod, with the vertical rod fixedly connected to the center of the disk; the first spring and the second spring are respectively fixed to the two end faces of the disk, the vertical rod passes through the interior of the second spring, and the end of the vertical rod away from the disk is connected to the driving mechanism.

[0008] Furthermore, the diameter of the disk is smaller than the inner diameter of the force-transmitting sleeve.

[0009] Furthermore, the outer diameters of both the first spring and the second spring are smaller than the inner diameter of the force-transmitting sleeve, and the inner diameter of the second spring is larger than the diameter of the vertical rod.

[0010] Furthermore, the ends of both the first spring and the second spring furthest from the disk are free ends.

[0011] Furthermore, the displacement measurement component includes a target plate and a laser displacement meter; the target plate is fixed on the vertical rod and moves synchronously with the force-applying rod; the laser displacement meter is located below the target plate and is fixed in place; the effective measurement range of the laser displacement meter is greater than the maximum moving distance of the force-applying rod.

[0012] Furthermore, the driving mechanism is a servo electric cylinder or a screw jack driven by a motor.

[0013] Furthermore, the displacement measurement component employs a sensor system capable of accurately measuring linear displacement.

[0014] In summary, compared with the prior art, the present invention has the following advantages: The technical solution provided by this invention involves setting a first spring and a second spring distributed along the axis inside the force transmission sleeve. A driving mechanism drives a force-applying rod to perform reciprocating linear motion, compressing the first or second spring to achieve automated loading. This allows for simultaneous loading of force values ​​in both positive and negative directions, ensuring continuous force values. By using the spring constant of the first or second spring and the distance the force-applying rod moves as measured by the displacement measuring component, the magnitude of the thrust or tension force on the force transmission sleeve is calculated, thus determining the force acting on the force sensor and ensuring the accuracy of the loaded force value. Furthermore, the force application device provided by this invention is flexible in installation and can be placed in any orientation, such as vertical or horizontal. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the force-applying device in an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the application of the force application device in force sensor calibration in an embodiment of the present invention.

[0017] Explanation of reference numerals in the attached drawings: 1-Force transmission sleeve; 2-Force application rod; 21-Disc; 22-Vertical rod; 3-First spring; 4-Second spring; 51-Target plate; 52-Laser displacement gauge; 6-Drive mechanism; 7-Force sensor; 8-Working platform; 9-U-shaped bracket; 10-Fixing plate. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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.

[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," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used 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 limiting this invention.

[0020] Furthermore, 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 indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] Example A force application device for calibrating a force sensor, such as Figure 1 and Figure 2 As shown, it includes a force transmission sleeve 1, a force application rod 2, a first spring 3, a second spring 4, a displacement measuring assembly, and a drive mechanism 6. The specific contents are as follows: The force transmission sleeve 1 is used to transmit force to the force sensor 7 to be calibrated. The force transmission sleeve 1 is a hollow cylindrical structure, and the center of its top is fixedly connected to the measuring end of the force sensor 7 to be calibrated.

[0022] The first spring 3 and the second spring 4 are used to generate spring force and are arranged inside the force transmission sleeve 1 along the axial direction, with the first spring 3 located above the second spring 4. The outer diameters of both the first spring 3 and the second spring 4 are slightly smaller than the inner diameter of the force transmission sleeve 1. The elastic force of the first spring 3 and the second spring 4 is applied to the force sensor to be calibrated through the force transmission sleeve 1. The first spring 3 and the second spring 4 can be replaced, and springs with appropriate pitch, stiffness coefficient, and other parameters are selected according to the range of the force sensor to be calibrated.

[0023] The force-applying rod 2 is used to compress the first spring 3 or the second spring 4, causing the first spring 3 or the second spring 4 to generate spring force. The force-applying rod 2 includes a coaxially arranged disk 21 and a vertical rod 22. One end of the vertical rod 22 is fixedly connected to the center of the disk 21. The disk 21 separates the first spring 3 and the second spring 4, which are respectively fixed to the two end faces of the disk 21. The vertical rod 22 passes through the interior of the second spring 4 and exits through the bottom end face of the force transmission sleeve 1, connecting with the drive mechanism 6. The reciprocating linear motion of the force-applying rod 2 drives the first spring 3 or the second spring 4 to compress. The diameter of the disk 21 is slightly smaller than the inner diameter of the force transmission sleeve 1, facilitating the free movement of the disk 21 along the axial direction inside the force transmission sleeve 1. The inner diameter of the second spring 4 is slightly larger than the diameter of the vertical rod 22.

[0024] The ends of the first spring 3 and the second spring 4 that are away from the disk 21 are both free ends. In the initial state, neither the first spring 3 nor the second spring 4 is in contact with the top or bottom wall of the force transmission sleeve 1.

[0025] The displacement measuring assembly is used to measure the movement distance of the force-applying rod 2. The displacement measuring assembly includes a target plate 51 and a laser displacement meter 52. The target plate 51 is fixed to one end of the vertical rod 22 that extends outside the force-transmitting sleeve 1 and moves synchronously with the force-applying rod 2. The laser displacement meter 52 is located below the target plate 51 and is fixed in place. The effective measurement range of the laser displacement meter 52 is greater than the maximum movement distance of the force-applying rod 2. The measurement accuracy of the laser displacement meter 52 directly reflects the accuracy of the applied force.

[0026] The displacement measurement component can be any sensor system capable of precisely measuring linear displacement, and can be selected according to actual needs.

[0027] The drive mechanism 6 can be a servo-driven electric cylinder or a motor-driven screw jack, or any conventional mechanism in the prior art that can achieve reciprocating linear motion of the force-applying rod 2. The output end of the drive mechanism 6 is fixedly connected to the bottom end of the vertical rod 22. The drive mechanism 6 can provide feedback on the movement distance of the force-applying rod 2 and cross-check it with the movement distance measured by the displacement measuring component.

[0028] Under the action of the drive mechanism 6, the force-applying rod 2 moves upward, the first spring 3 is compressed, the second spring 4 is in a free state, and the force-transmitting sleeve 1 is subjected to an upward thrust; the force-applying rod 2 moves downward, the second spring 4 is compressed, the first spring 3 is in a free state, and the force-transmitting sleeve 1 is subjected to a downward pull; the target plate 51 of the displacement measuring component moves synchronously with the force-applying rod 2. Based on the distance the force-applying rod 2 moves as measured by the laser displacement meter 52, and the spring constant of the first spring 3 or the second spring 4, the magnitude of the thrust or pull force on the force-transmitting sleeve 1 can be calculated, and thus the force acting on the force sensor 7 can be known.

[0029] The elastic force of the first spring 3 or the second spring 4 can be calculated using the spring constant and the amount of spring deformation. When the deformation distance of the first spring 3 or the second spring 4 is... △ L When the spring constant is K, the spring force F = K × △ L .

[0030] like Figure 2As shown, it also includes a working platform 8, on which a U-shaped bracket 9 is fixed. The drive mechanism 6 is installed on the top of the working platform 8. The crossbeam of the U-shaped bracket 9 is used to install the force sensor to be calibrated. A fixing plate 10 is fixedly installed on the side wall of the U-shaped bracket 9, and the laser displacement meter 52 is installed on the top of the fixing plate 10. During calibration, the fixed end of the force sensor 7 is fixed to the bottom of the crossbeam of the U-shaped bracket 9, and the measuring end of the force sensor 7 is fixed to the top of the force transmission sleeve 1 to complete the installation.

[0031] The working principle of the force application device for force sensor calibration provided by this invention is as follows: Figure 1 As shown, Initially, the free ends of the first spring 3 and the second spring 4 are not in contact with the force transmission sleeve 1, and the force transmission sleeve 1 is not under force. When the driving mechanism 6 drives the force application rod 2 downward, the distance between the free end of the second spring 4 and the force transmission sleeve 1 continuously decreases. When they come into contact, they continue to move downward, and the second spring 4 is compressed, generating elastic force. The force transmission sleeve 1 is subjected to a downward force, which is then transmitted to the force sensor 7. During the downward movement of the force application rod 2, the target plate 51 moves along with it. Assuming that the laser displacement gauge 52 measures the distance L of the target plate 51, and initially, the distance from the free end of the second spring 4 to the force transmission sleeve 1 is L1, the distance measured by the laser displacement gauge 52 is L0, and the spring constant of the second spring 4 is K2, then the elastic force F can be calculated as follows: F = K2 × (L - L0 - L1) When the elastic force F is negative, it means that the force is directed downwards.

[0032] Similarly, when the drive mechanism 6 drives the force-applying rod 2 to move upward, the first spring 3 is compressed, generating an upward elastic force. Therefore, the force sensor can be loaded with force in both positive and negative directions.

[0033] Figure 2 This is a schematic diagram illustrating the application of the present invention in the calibration of a single-axis force sensor. The single-axis force sensor 7 is fixed to the crossbeam of the U-shaped bracket 9, with its measuring end connected to the top of the force transmission sleeve 1. The drive mechanism 6 is a motor-driven screw jack, fixed to the working platform 8, using the motor to drive the screw to achieve up-and-down movement. The top of the screw is connected to the bottom end of the vertical rod 22 of the force-applying rod 2. When moving upwards, the first spring 3 is compressed, thus applying upward pressure to the force transmission sleeve 1, thereby applying an upward force to the force sensor 7. When moving downwards, the second spring 4 is compressed, thus applying downward tension to the force transmission sleeve 1, thereby applying a downward force to the force sensor 7. The laser displacement gauge 52 is fixed to the fixing plate 10 on the vertical beam of the U-shaped bracket 9. Through the target plate 51 fixed to the vertical rod 22 of the force-applying rod 2, the distance the force-applying rod 2 moves is measured. Based on the spring constant, the magnitude of the applied force can be calculated.

[0034] The force sensor calibration device provided by this invention achieves precise loading of continuous force values ​​in both positive and negative directions through the spring forces of the first and second springs arranged along the axis inside the force transmission sleeve, and can effectively avoid the impact generated when applying force, thus protecting the force sensor. By using a laser displacement gauge to measure the deformation of the first or second spring and the spring constant, the magnitude of the thrust or tension force on the force transmission sleeve is calculated, thereby determining the force acting on the force sensor and ensuring the accuracy of the loaded force value.

[0035] The force application device for force sensor calibration provided by this invention is highly adaptable. By replacing the first spring and the second spring, precise force application can be achieved when calibrating force sensors with different ranges. The force application device provided by this invention facilitates automated loading during force sensor calibration and offers high installation flexibility, allowing placement in any orientation, such as vertical or horizontal.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A force sensor calibration force applying device characterized by, The application relates to a force transmission sleeve (1) for transmitting force to a force sensor to be calibrated, a first spring (3) and a second spring (4) arranged inside the force transmission sleeve (1) along an axial direction for generating spring force, a force applying rod (2) with one end inside the force transmission sleeve (1) for compressing the first spring (3) or the second spring (4) and the other end extending outside the force transmission sleeve (1), a driving mechanism (6) connected to the end of the force applying rod (2) extending outside the force transmission sleeve (1) for driving the force applying rod (2) to make reciprocating linear motion, and a displacement measuring assembly for measuring the moving distance of the force applying rod (2). The end of the force transmission sleeve (1) away from the driving mechanism (6) is connected to the measuring end of the force sensor to be calibrated. The force applying rod (2) comprises a disc (21) and a vertical rod (22) arranged coaxially, the vertical rod (22) is fixedly connected to the central position of the disc (21), the first spring (3) and the second spring (4) are fixed on the two end faces of the disc (21) respectively, the vertical rod (22) penetrates through the inside of the second spring (4), and the end of the vertical rod (22) away from the disc (21) is connected to the driving mechanism (6). The diameter of the disc (21) is smaller than the inner diameter of the force transmission sleeve (1). The outer diameters of the first spring (3) and the second spring (4) are all smaller than the inner diameter of the force transmission sleeve (1), and the inner diameter of the second spring (4) is larger than the diameter of the vertical rod (22). The ends of the first spring (3) and the second spring (4) away from the disc (21) are both free ends.

2. The force sensor calibration force applying apparatus according to claim 1, characterized by, The displacement measuring assembly comprises a target plate (51) and a laser displacement meter (52), the target plate (51) is fixed on the vertical rod (22) and moves synchronously with the force applying rod (2), the laser displacement meter (52) is fixed below the target plate (51) and does not move, and the effective measuring range of the laser displacement meter (52) is larger than the maximum moving distance of the force applying rod (2).

3. The force sensor calibration force applying apparatus according to claim 1, wherein The driving mechanism (6) is a servo cylinder or a screw rod elevator driven by a motor.

4. The force sensor calibration force applying apparatus according to claim 3, wherein The displacement measuring assembly adopts a sensor system capable of accurately measuring linear displacement.

5. The force sensor calibration force applying apparatus according to claim 3, wherein ​ 6. The force sensor calibration force applying apparatus according to claim 3, wherein ​ 7. The force sensor calibration force applying apparatus according to claim 3, wherein ​ 8. The force sensor calibration force applying apparatus according to claim 1, wherein ​ 9. The force sensor calibration force applying apparatus according to claim 1, wherein ​

Images