A scalable force sensor and a calibration device comprising the same

Abstract

The application discloses a telescopic force sensor and a calibration device comprising the force sensor, and belongs to the technical field of sensor equipment.The telescopic force sensor comprises a pull ring, a measuring head, a sensor telescopic rod, a deformation body, a strain gauge and a nut, the sensor telescopic rod can be elongated and shortened according to requirements, and the measuring head is processed with a hole; when the pulling force needs to be measured, the pull ring is passed through the hole on the measuring head, and the pulling force can be measured by pulling the pull ring; when the pressure needs to be measured, the pull ring is removed, and the pressure can be measured by pressing the measuring head.The force sensor calibration table comprises a bottom plate, a supporting seat, a calibration table telescopic rod, a cross beam, a pulling and pressing force sensor and a micro-motion lifting table, can adapt to the re-calibration of the force sensor, and can determine the relationship between the measured force and the output voltage of the telescopic force sensor under a new length.The application is suitable for force measurement of narrow space positions such as deep hole bottoms, effectively expands the application scene of the force sensor, and improves the measurement precision of the force sensor.

Description

Technical Field

[0001] This invention belongs to the field of sensor equipment technology, specifically relating to a stretchable force sensor and a calibration device including the force sensor. Background Technology

[0002] In recent years, with the rapid development of high-end equipment and the continuous improvement of control precision, force sensors have become an indispensable core component in many fields, and the requirements for the adaptability of force sensors to various scenarios are also increasing. Resistance strain gauge force sensors are force measurement devices that convert force signals into electrical signals, consisting of a deformation device, strain gauge, and bridge circuit. The magnitude of the input force can be determined based on the magnitude of the output electrical signal. They are widely used due to their advantages such as high precision, small size, convenient installation, and easy acquisition and processing of output signals. Sensor calibration is a crucial step in ensuring the accuracy and precision of sensors. The calibration of resistance strain gauge force sensors involves establishing a one-to-one correspondence between the measured force and the output electrical signal of the bridge circuit using a force sensor calibration device. When the sensor structure changes, it needs to be recalibrated to determine the relationship between the measured force and the output electrical signal under the new structure.

[0003] The inventors discovered that in practical applications, force measurement needs sometimes arise in complex environments such as the bottom of deep holes and narrow gaps. Existing force sensors are insufficient to meet the force measurement requirements in such scenarios. To solve this problem, it is even necessary to specially design the structure of the force sensor according to the specific scenario and re-manufacture a dedicated force sensor. This not only requires high technical expertise but also wastes time, increases costs, and seriously affects economic efficiency. This invention proposes a retractable force sensor that uses the extension and retraction of a telescopic rod to drive the probe forward and backward, allowing the probe to smoothly pass through narrow areas to reach the measurement point. Furthermore, this invention provides a calibration device for this retractable force sensor, used for instant calibration of the force sensor after length changes. The device is simple in structure and easy to operate. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a retractable force sensor and a calibration device including the force sensor, for force measurement in complex environments such as the bottom of deep holes and narrow slits. This effectively expands the application scenarios of force sensors and has significant advantages in force measurement in complex and confined spaces.

[0005] To achieve the aforementioned objective, the present invention employs the following technical solution:

[0006] According to a first aspect of the present invention, the present invention first provides a retractable force sensor, including a probe, a sensor telescopic rod, a deformable part, and a nut assembly; the deformable part has a deformable part mounting portion in the middle, and deformable areas and deformable part fixing portions are symmetrically connected to the left and right sides of the deformable part mounting portion in sequence; the deformable area is used to generate deformation when subjected to force; the deformable part fixing portion is machined with screw mounting holes; at least one of the upper and lower surfaces of the deformable area is attached with strain gauges, and the strain gauges are connected to form a Wheatstone bridge for converting force signals into electrical signals;

[0007] The deformable part is sleeved on the top circumferential surface of the sensor telescopic rod. The top of the sensor telescopic rod has a first cylindrical protrusion with an external thread that matches the nut assembly. The nut assembly is used to tighten and loosen the deformable part. The bottom end of the sensor telescopic rod is fixedly connected to the probe. The probe has a through hole on its circumferential surface for installing a pull ring.

[0008] According to one embodiment of the present invention, the probe has a second cylindrical protrusion at its top end, and the second cylindrical protrusion is machined with an external thread that connects to the bottom end of the sensor telescopic rod.

[0009] According to one embodiment of the present invention, the deformation zone is made of a flexible material, and the deformation fixing part is made of a rigid material.

[0010] According to one embodiment of the present invention, the deformation zone includes a tensile deformation zone and a compressive deformation zone. The lower surface of the tensile deformation zone and the upper surface of the compressive deformation zone respectively include arcuate grooves with openings facing downward and upward. The strain gauges are respectively attached to the upper surface of the tensile deformation zone and the lower surface of the compressive deformation zone. The upper surface of the tensile deformation zone and the lower surface of the compressive deformation zone are connected to each other.

[0011] According to a second aspect of the present invention, the present invention also discloses a calibration platform including the above-mentioned retractable force sensor, the calibration platform further comprising: a base plate, a support base, a calibration platform telescopic rod, a tension / compression sensor, and a micro-motion lifting platform; the micro-motion lifting platform is fixed in the middle of the base plate, the tension / compression sensor is fixed on the micro-motion lifting platform, and the top end of the tension / compression sensor has a threaded bottom hole for mounting a hook;

[0012] Four support seats are fixed at the four corners of the base plate, and each support seat is fixedly connected to the calibration platform telescopic rod in the longitudinal direction. A pair of crossbeams are horizontally connected between each pair of calibration platform telescopic rods in a parallel manner with intervals between them. The middle part of each pair of crossbeams has a through hole corresponding to the screw mounting hole of the deformation fixing part.

[0013] As a further technical solution, the sensitivity of the tensile / compressive force sensor is higher than that of the stretchable force sensor.

[0014] As a further technical solution, the micro-motion lifting platform includes: a lifting platform fixing component, a tension spring, a lifting platform movable component, a rotating block, a rotating shaft, and a screw rod. The lifting platform fixing component is fixedly connected to the base plate, the lifting platform movable component is slidably connected to the lifting platform fixing component, the two ends of the tension spring are fixedly connected to the lifting platform fixing component and the lifting platform movable component respectively, the rotating shaft is fixedly connected to the lifting platform movable component, the rotating block is rotatably connected to the rotating shaft, and the screw rod is installed on the lifting platform fixing component.

[0015] As a further technical solution, the movable component of the lifting platform has a cylindrical protrusion. One end of the rotating block contacts the cylindrical protrusion of the movable component, and the other end contacts the screw of the screw rod. Rotating the knob of the screw rod causes the screw rod to move back and forth. The back and forth movement of the screw rod causes the rotating block to rotate, which in turn causes the movable component of the lifting platform to slide up or down, further causing the tension and compression sensors to move up or down.

[0016] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages:

[0017] 1. The retractable force sensor of the present invention drives the probe to move forward or backward by extending and retracting the telescopic rod, which can effectively complete force measurement when the distance between the measured point and the force sensor is different. Especially when facing complex and narrow space environments such as the bottom of deep holes and narrow gaps, the force measurement needs can be met without designing a dedicated force sensor.

[0018] 2. The retractable force sensor of the present invention can measure both pressure and tension. The conversion between pressure measurement and tension measurement can be achieved simply by removing or installing the pull ring, making it easy to operate.

[0019] 3. When the length of the retractable force sensor changes, the height of the crossbeam can be adjusted by using the telescopic rod of the calibration platform to re-fix the retractable force sensor on the force sensor calibration platform. The operation is simple and can quickly achieve high-precision calibration of the retractable force sensor under different length conditions, and efficiently complete the force measurement task at force measurement points at different distances. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the main view of a retractable force sensor without a pull ring.

[0021] Figure 2 This is a schematic diagram of the structure of a retractable force sensor with a pull ring.

[0022] Figure 3 This is a schematic diagram of the calibration platform without the retractable force sensor installed.

[0023] Figure 4This is a schematic diagram of the calibration platform during pressure calibration.

[0024] Figure 5 This is a schematic diagram of the calibration platform when calibrating tensile force.

[0025] Figure 6 This is a schematic diagram of the micro-motion lifting platform.

[0026] The attached figures are labeled as follows:

[0027] 1. Base plate; 2. Support base; 3. Calibration table telescopic rod; 4. Crossbeam; 5. Telescopic force sensor; 51. Pull ring; 52. Probe; 53. Sensor telescopic rod; 54. Deformation fixing part; 55. Strain gauge; 56. Nut assembly; 6. Tension and compression sensor; 7. Micro-motion lifting platform; 71. Lifting platform fixing part; 72. Tension spring; 73. Lifting platform moving part; 74. Rotating block; 75. Rotating shaft; 76. Helical rod; 8. Pull hook. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0029] For ease of description, the terms "up," "down," "left," and "right" appearing in this application only indicate that they correspond to the up, down, left, and right directions in the accompanying drawings. They do not limit the structure and are merely for the purpose of describing the invention and simplifying the description. They 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, and therefore should not be construed as a limitation of this application. The following are specific embodiments:

[0030] Example 1

[0031] The following is in conjunction with the appendix Figure 1-6 This embodiment will be described in further detail.

[0032] The structure of the stretchable force sensor 5 in this embodiment is as follows: Figure 1As shown, the sensor includes a probe 52, a sensor telescopic rod 53, a deformation type, and a nut assembly 56. The deformation type has a deformation type mounting portion in its center. A deformation zone and a deformation type fixing portion 54 are symmetrically connected to the left and right sides of the deformation type mounting portion. The deformation zone is used to generate deformation under force. The deformation type fixing portion 54 has screw mounting holes. The deformation zone includes a tensile deformation zone and a compressive deformation zone. The lower surface of the tensile deformation zone and the upper surface of the compressive deformation zone respectively include downward-facing and upward-facing arc-shaped grooves to generate greater deformation under force, thereby improving the measurement accuracy of the force sensor. Strain gauges 55 are respectively attached to the upper surface of the tensile deformation zone and the lower surface of the compressive deformation zone. The upper surface of the tensile deformation zone and the lower surface of the compressive deformation zone are connected to each other. Multiple strain gauges 55 are connected to form a Wheatstone bridge for converting force signals into electrical signals.

[0033] The deformable part is fitted onto the top circumferential surface of the sensor telescopic rod 53, and has a first cylindrical protrusion above the top of the sensor telescopic rod 53. The first cylindrical protrusion has external threads machined on it to connect with the nut assembly 56. The nut assembly 56 is used to tighten and loosen the deformable part. The probe 52 has a second cylindrical protrusion at its top, and the second cylindrical protrusion has external threads machined on it to connect with the bottom end of the sensor telescopic rod 53. The probe 52 has a through hole on its circumferential surface for mounting a pull ring 51. The pull ring 51 can be mounted on or removed from the probe 52. Figure 2 As shown.

[0034] This embodiment also provides a calibration device including the force sensor, which includes: a base plate 1, a support base 2, a calibration platform telescopic rod 3, a crossbeam 4, a telescopic force sensor 5, a tension / compression sensor 6, and a micro-motion lifting platform 7.

[0035] In this embodiment, the upper surface of the base plate 1 has threaded bottom holes at the four corners for the installation and fixing of the support base 2, and the upper surface of the base plate 1 also has threaded bottom holes at the middle position for the installation and fixing of the micro-motion lifting platform 7.

[0036] There are four support bases 2, which are fixed to the four corners of the base plate 1 by screws. The top of the support base 2 has a cylindrical protrusion with external threads.

[0037] There are four telescopic rods 3 on the calibration platform. One end of each telescopic rod 3 has a threaded bottom hole, and the other end has a cylindrical protrusion with external threads. Each telescopic rod 3 is fixedly connected to a support base 2 through the threaded bottom hole. The telescopic rods 3 can be extended or shortened.

[0038] There are two crossbeams 4, each with two through holes, each passing through a cylindrical protrusion at one end of a calibration platform telescopic rod 3. That is, every two calibration platform telescopic rods 3 together support one crossbeam 4. The crossbeam 4 is fixed to the calibration platform telescopic rods 3 with nuts. A threaded bottom hole is machined in the middle of the lower surface of the crossbeam 4 for mounting and fixing the retractable force sensor 5. Extending or shortening the calibration platform telescopic rod 3 causes the crossbeam 4 to move upward or downward, accommodating the installation of retractable force sensors 5 of different lengths, such as... Figure 3 , Figure 4 As shown.

[0039] Furthermore, the structure of the micro-motion lifting platform 7 is as follows: Figure 6 As shown, it includes: a lifting platform fixing component 71, a tension spring 72, a lifting platform movable component 73, a rotating block 74, a rotating shaft 75, and a screw rod 76.

[0040] The lifting platform fixing component 71 is fixed to the middle of the base plate 1 with screws. A slide rail is machined on one side of the top of the lifting platform fixing component 71. The lifting platform movable component 73 is slidably connected to the lifting platform fixing component 71 through the slide rail, and the lifting platform movable component 73 can slide up and down relative to the lifting platform fixing component 71. The rotating shaft 75 is fixedly connected to the lifting platform fixing component 73 by threads. The rotating block 74 is rotatably connected to the rotating shaft 75, and the rotating block 74 can rotate around the rotating shaft 75. A mounting hole is machined on one side of the lifting platform fixing component 71, and an internal thread is machined in the mounting hole. The outer ring of the screw rod 76 is fixed by engaging the external thread on its outer surface with the internal thread of the mounting hole of the lifting platform fixing component 71. By rotating the knob of the screw rod 76, the screw of the screw rod 76 can move back and forth relative to the outer ring.

[0041] The movable component 73 of the lifting platform has a downward-facing cylindrical protrusion. One end of the rotating block 74 contacts the cylindrical protrusion of the movable component 73, and the other end contacts the tip of the screw of the screw rod 76. Rotating the knob of the screw rod 76 moves the screw rod forward or backward, thereby driving the rotating block 74 to rotate, and further driving the movable component 73 of the lifting platform to slide upward or downward. A tension spring 72 is installed between the fixed component 71 of the lifting platform and the movable component 73 of the lifting platform to ensure that the movable component 73 of the lifting platform remains stable during sliding.

[0042] The tension / compression sensor 6 is fixed to the top of the movable part 73 of the lifting platform by screws. A threaded hole is machined at the center of the upper surface of the tension / compression sensor 6 for mounting and fixing the hook 8. Removing the hook 8 and pressing the upper surface of the tension / compression sensor 6 measures the pressure; installing the hook 8 and pulling it measures the tension. Figure 5 As shown.

[0043] The working process of the force measurement device in this embodiment is as follows:

[0044] 1. Determine the length of the telescopic rod in the telescopic force sensor based on the specific measurement scenario. If pressure needs to be measured, remove the pull ring; if tension needs to be measured, attach the pull ring.

[0045] 2. Fix the retractable force sensor to the crossbeam of the force sensor calibration platform. Adjust the length of the telescopic rod of the calibration platform. When measuring pressure, ensure that the probe is in contact with the upper surface of the tension / compression sensor. When measuring tension, ensure that the pull ring is hooked onto the pull hook and in contact with it. At this time, the output value of the tension / compression sensor is zero.

[0046] 3. When measuring pressure, turn the screw rod to move the micro-adjustment lifting platform upward; when measuring tension, turn the screw rod to move the micro-adjustment lifting platform downward. Whenever the output of the tension / compression sensor changes by a certain feed amount, record the corresponding output voltage value of the stretchable force sensor to obtain a corresponding input-output data point for the stretchable force sensor.

[0047] 4. Based on the calibrated range and accuracy requirements, obtain multiple input-output data points, determine the relationship between the measured force and output voltage under the current length state of the stretchable force sensor, and complete the calibration.

[0048] 5. Remove the retractable force sensor from the force sensor calibration table, fix it at the position to be measured, and perform force measurement.

[0049] Those skilled in the art will readily understand that the above description is merely 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 scope of protection of the present invention.

Claims

1. A stretchable force sensor, characterized in that, The device includes a probe, a sensor telescopic rod, a deformable part, and a nut assembly. The deformable part has a deformable part mounting section in the middle. A deformable area and a deformable part fixing section are symmetrically connected to the left and right sides of the deformable part mounting section. The deformable area is used to generate deformation when subjected to force. The deformable part fixing section is machined with screw mounting holes. At least one of the upper and lower surfaces of the deformable area is attached with a strain gauge. The strain gauges are connected to form a Wheatstone bridge for converting force signals into electrical signals. The deformable part is sleeved on the top circumferential surface of the sensor telescopic rod. The top of the sensor telescopic rod has a first cylindrical protrusion. The first cylindrical protrusion is machined with an external thread that matches the nut assembly. The nut assembly is used to tighten and loosen the deformable part. The bottom end of the sensor telescopic rod is fixedly connected to the probe. The probe has a through hole on its circumferential surface for installing a pull ring. The deformation zone includes a tensile deformation zone and a compressive deformation zone. The lower surface of the tensile deformation zone and the upper surface of the compressive deformation zone respectively include arcuate grooves with openings facing downwards and upwards. The strain gauges are respectively attached to the upper surface of the tensile deformation zone and the lower surface of the compressive deformation zone. The upper surface of the tensile deformation zone and the lower surface of the compressive deformation zone are connected to each other.

2. The stretchable force sensor according to claim 1, characterized in that, The probe has a second cylindrical protrusion at its top, and the second cylindrical protrusion is machined with an external thread that connects to the bottom end of the sensor telescopic rod.

3. The stretchable force sensor according to claim 1, characterized in that, The deformation zone is made of a flexible material, while the deformation fixing part is made of a rigid material.

4. A calibration platform comprising the retractable force sensor according to any one of claims 1-3, characterized in that, The calibration platform also includes: a base plate, a support base, a calibration platform telescopic rod, a tension / compression sensor, and a micro-motion lifting platform; the micro-motion lifting platform is fixed in the middle of the base plate, the tension / compression sensor is fixed on the micro-motion lifting platform, and the top of the tension / compression sensor has a threaded bottom hole for installing a hook; Four support seats are fixed at the four corners of the base plate, and each support seat is fixedly connected to the calibration platform telescopic rod in the longitudinal direction. A pair of crossbeams are horizontally connected between each pair of calibration platform telescopic rods in a parallel manner with intervals between them. The middle part of each pair of crossbeams has a through hole corresponding to the screw mounting hole of the deformation fixing part.

5. The calibration stage according to claim 4, characterized in that, The sensitivity of the tensile / compressive force sensor is higher than that of the stretchable force sensor.

6. The calibration stage according to claim 4, characterized in that, The micro-motion lifting platform includes: a lifting platform fixing component, a tension spring, a lifting platform movable component, a rotating block, a rotating shaft, and a screw rod. The lifting platform fixing component is fixedly connected to the base plate, the lifting platform movable component is slidably connected to the lifting platform fixing component, the two ends of the tension spring are fixedly connected to the lifting platform fixing component and the lifting platform movable component respectively, the rotating shaft is fixedly connected to the lifting platform movable component, the rotating block is rotatably connected to the rotating shaft, and the screw rod is installed on the lifting platform fixing component.

7. The calibration stage according to claim 6, characterized in that, The movable component of the lifting platform has a cylindrical protrusion. One end of the rotating block contacts the cylindrical protrusion of the movable component of the lifting platform, and the other end contacts the screw of the screw rod.

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