A large range high-precision pull rope sensor calibration system

Abstract

The utility model relates to a kind of large range high-precision pull rope sensor calibration system, the pull rope sensor calibration system includes calibration device and the host computer connected with calibration device, the calibration device includes bottom plate and is respectively arranged on bottom plate: fixed position: to realize the lateral positioning of pull rope sensor to be calibrated;Steel wire rope winding assembly: with the pull ring of pull rope sensor to be calibrated and is hung, to be used in calibration by pull ring to pull out steel wire rope and the steel wire rope that has been pulled out is stored;High-precision length measuring component: to realize the high-precision calibration of calibration section steel wire rope, compared with prior art, the utility model has the advantages of small footprint, low cost, applicable to large range pull rope sensor product, high precision, automatic calibration etc..

Description

Technical Field

[0001] This utility model relates to the field of rope sensor manufacturing, and in particular to a large-range, high-precision rope sensor calibration system. Background Technology

[0002] A pull-rope displacement sensor is a detection device that converts linear displacement into measurable electrical signals (such as digital or analog signals). Its core principle is to achieve displacement measurement through "pulling and releasing the rope - mechanical transmission - signal conversion". It is widely used in monitoring the position and travel of machine tools, automated production lines, construction machinery, elevators and other scenarios.

[0003] The final step in the assembly process of a draw-wire displacement sensor before it leaves the factory is length calibration. Currently, when calibrating a draw-wire displacement sensor, high-precision calibration measuring equipment (such as high-precision calipers, laser rangefinders, etc.) is used. First, the draw-wire displacement sensor to be calibrated is fixed at the zero point of a horizontal support with a length greater than its range. Then, the draw-wire of the sensor is pulled horizontally until it reaches full range. During this process, the output of multiple pre-set length calibration point positions is obtained. Finally, calibration is completed through methods such as linear fitting.

[0004] However, since the drawstring of the drawstring displacement sensor needs to be pulled out to full scale during calibration (the range of a large-range drawstring sensor is generally above 5m), a large horizontal support and space are required (generally 1.1-1.2 times the range). In addition, high-precision calibration measurement equipment is very expensive and has high requirements for the calibration environment. Therefore, it is necessary to design a calibration system that takes into account space, environment and cost constraints, while still ensuring the calibration accuracy requirements. Utility Model Content

[0005] To address the technical problems in the background art, this utility model provides a large-range, high-precision rope sensor calibration system.

[0006] A high-range, high-precision draw rope sensor calibration system includes a calibration device and a host computer connected to the calibration device. The calibration device includes a base plate and components respectively mounted on the base plate:

[0007] Fixed position: Used to achieve lateral positioning of the pull-wire sensor to be calibrated;

[0008] Wire rope winding assembly: It is attached to the pull ring of the pull rope sensor to be calibrated, so as to pull out the wire rope through the pull ring during calibration and to store the pulled-out wire rope.

[0009] High-precision length measuring component: used to achieve high-precision calibration of the wire rope in the calibration section.

[0010] Furthermore, a sensor mounting and positioning unit is provided at the fixed position. The sensor mounting and positioning unit consists of a horizontal pad and a vertical plate set on the pad. The pull rope sensor to be calibrated is laterally fixed on the vertical plate.

[0011] Furthermore, the wire rope winding assembly includes a wire rope take-up wheel rotatably mounted on a base plate, a motor mounting plate fixed on the base plate, and a stepper motor fixedly mounted on the motor mounting plate with its output end rotating synchronously with the wire rope take-up wheel. The stepper motor is connected to a host computer.

[0012] Furthermore, the high-precision length measuring component is positioned between the rope sensor to be calibrated and the wire rope winding assembly, and includes a stabilizing transmission unit, a high-precision magnetic encoder, a clamping adjustment unit, and a linear holding unit. The stabilizing transmission unit includes an adapter plate and a length-recording wheel. The adapter plate is fixed to the outer edge of the magnetic encoder mounting hole in the middle of the base plate. The high-precision magnetic encoder is positioned below the magnetic encoder mounting hole and fixed to the adapter plate, with its output shaft vertically positioned at the center of the magnetic encoder mounting hole. The length-recording wheel is sleeved on the output shaft of the high-precision magnetic encoder.

[0013] Furthermore, the clamping adjustment unit includes a clamping wheel that cooperates with the length-counting wheel to clamp the wire rope, a telescopic arm for rotatably mounting the clamping wheel, and a support frame for supporting the telescopic arm. The telescopic arm provides clamping force through a spring, and the support frame adjusts its position on the base plate through a strip hole at the bottom, thereby adjusting the distance and clamping force between the clamping wheel and the length-counting wheel.

[0014] Furthermore, the clamping force N between the clamping wheel and the length-measuring wheel satisfies the following condition:

[0015] (1) Ensure smooth recovery: Static friction force f = μN < minimum recovery force F of the rope sensor coil spring. min卷 μ is the coefficient of friction;

[0016] (2) No relative slippage occurs between the wire rope and the counting wheel: the static friction force f > the force required to rotate the counting wheel f. 需 Furthermore, note that the roundness and cylindricity of the long wheel are both less than the corresponding error threshold;

[0017] (3) To avoid slippage of the stepper motor during start / stop and excessive speed fluctuation during uniform rotation: the start / stop acceleration and the rate of change of speed fluctuation during rotation should be less than the static friction force f / the mass of the wire rope m;

[0018] (4) The clamping force does not cause the wire rope to deform, nor does it cause the surface of the long pulley to deform: the clamping force N < the maximum force Nmax that causes extrusion deformation.

[0019] Furthermore, the linear holding unit includes a first guide wheel and a second guide wheel that are rotatably mounted on the base plate and have the same structure. The first guide wheel is disposed between the clamping adjustment unit and the wire rope winding assembly, and the second guide wheel is disposed between the clamping adjustment unit and the pull rope sensor to be calibrated. The sides of the first guide wheel and the second guide wheel are respectively provided with wire rope grooves for limiting the wire rope.

[0020] Furthermore, the first guide wheel is provided on one side of the clamping wheel of the wire rope, and the second guide wheel is provided on one side of the length counting wheel of the wire rope;

[0021] Alternatively, two first guide wheels are arranged side by side along the wire rope direction on the side of the clamping wheel of the wire rope, and one second guide wheel is arranged on the side of the length counting wheel of the wire rope.

[0022] Alternatively, one first guide wheel can be installed on each side of the wire rope, and one second guide wheel can be installed on each side of the wire rope.

[0023] A method for calibrating a pull-string sensor includes the following steps:

[0024] 1) Fix the pull rope sensor to be calibrated, and connect the pull rope sensor to be calibrated and stepper motor 1 to the host computer and communicate with them respectively;

[0025] 2) Automatic length calibration:

[0026] 21) Configure the range L, calibration interval Δl and correction length L0 of the pull rope sensor to be calibrated. The correction length L0 is specifically the length of the wire rope pulled out when the pull ring is pulled out from the outlet until it is hooked onto the wire rope storage wheel. The pull ring is hooked onto the hooking point of the wire rope storage wheel, and the clamping adjustment unit is adjusted to clamp the wire rope.

[0027] 22) Positive range calibration: Start the stepper motor to rotate forward and control the stepper motor to step at the set calibration interval Δl. Record the output value a corresponding to each calibration point under the positive range. n正 Automatic calibration of the positive range is completed;

[0028] 23) Reverse Range Calibration: Start the stepper motor in reverse and control it to step at the set calibration interval Δl. Record the output value a corresponding to each calibration point under reverse range. n反 ;

[0029] 24) Based on the recorded output values ​​of each calibration point in both forward and reverse ranges, calculate the average value as the final calibration value a for that calibration point. n If n is the calibration point number, then a n =a n正 +a n反 ;

[0030] 25) Linear interpolation is used to calibrate the length between two adjacent calibration points, and finally the calibration of the entire range is completed.

[0031] Furthermore, when the pull ring is pulled out from the outlet of the cable sensor to be calibrated until it is hooked onto the wire rope storage wheel, and the distance the wire rope is pulled out is greater than K times the calibration interval, where K is an integer and K≥1, then the first K calibration points that cannot be automatically calibrated are individually calibrated by setting K pull ring hanging points on the base plate. When the pull ring is hooked onto the kth pull ring hanging point, the corresponding calibration point is k*Δl. At this time, the host computer configures the initial value of the high-precision magnetic encoder to the correction length L0.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] I. Small footprint and low cost: The length of the calibration device of this utility model is only 0.5m, which is much smaller than the existing calibration device scheme that uses a horizontal support. Moreover, the manufacturing cost of the calibration device is also much lower than the existing calibration devices using laser, measuring ruler and other methods.

[0034] II. High Precision: This utility model ensures the straightness of the wire rope in the calibration section through the guide wheel of the linear holding unit, and ensures that the wire rope will neither slip relative to each other nor get stuck through the adjustment of the clamping force of the clamping adjustment unit. Combined with a high-precision magnetic encoder with stable transmission, the calibration device of this utility model has an accuracy error within 4mm. For a rope sensor product with a range of 8000mm, its equivalent accuracy is higher than 0.05%.

[0035] III. Automatic Calibration: This utility model achieves automatic calibration of all calibration points in both forward and reverse ranges through the control and calibration program of the host computer. The operation is simple, and the calibration time for each pull rope sensor product is shortened to less than 2 minutes (the original manual calibration required 40 minutes per product). For calibration points that cannot be automatically calibrated due to the influence of the calibration section length, this utility model also sets up a separate calibrated pull ring hanging point and a correction length to achieve the calibration of these calibration points. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the calibration device.

[0037] Figure 2 This is a top view of the calibration device.

[0038] Figure 3 This is a schematic diagram of the main structure of the calibration device;

[0039] Figure 4 This is a left sectional view of the calibration device;

[0040] Figure 5 This is a schematic diagram of the clamping adjustment unit.

[0041] Figure 6 This is a schematic diagram of the installation structure of the clamping adjustment unit and the stabilizing transmission unit.

[0042] Figure 7 The diagrams show the design schemes for the number of guide wheel positions, where Figure (7a) is the first design scheme, Figure (7b) is the second design scheme, and Figure (7c) is the third design scheme.

[0043] Figure 8 This is a flowchart illustrating the calibration method for the pull-rope sensor.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1. Stepper motor; 2. First guide wheel; 3. Clamping wheel; 4. Second guide wheel; 5. Cable sensor to be calibrated; 6. Base plate; 7. Support leg; 8. Length counting wheel; 9. Adapter plate; 10. Motor mounting plate; 11. Wire rope storage wheel; 12. High-precision magnetic encoder; 13. Controller; 14. Pull ring; 15. Bearing; 16. Clamping adjustment unit. Detailed Implementation

[0046] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. This embodiment is based on the technical solution of the present invention and provides detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following embodiments.

[0047] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0048] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the utility model product is usually placed in during use. They are only for the convenience of describing the utility model 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 the utility model.

[0049] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0050] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0051] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0052] Example

[0053] This utility model provides a high-range, high-precision rope sensor calibration system. The system includes a calibration device for high-precision calibration of the rope sensor and a corresponding host computer. The host computer controls and drives the calibration device and collects data through the control and calibration program running on it to complete the calibration process of the rope sensor 5 to be calibrated.

[0054] like Figure 1 As shown, in this example, the calibration device includes a horizontally placed base plate 6, a wire rope winding assembly fixed on the left side of the base plate 6, a high-precision length measuring assembly fixed in the middle of the base plate 6, and a fixing position on the right side of the base plate 6 for installing the pull rope sensor 5 to be calibrated. In addition, to prevent the influence of personnel and environment during calibration, a transparent plastic protective cover is provided on the base plate 6 to protect the components on the base plate 6 and ensure that they are not disturbed by the outside world during automatic calibration. The structure and function of each component are described below.

[0055] exist Figure 2-4 In this design, the base plate 6 is a metal plate with rounded corners. Mounting holes for mounting four legs 7 are made at the four corners of the base plate 6. The four legs 7 are installed and tightened with nuts. The four legs 7 are then leveled to ensure that the base plate 6 is in a horizontal position (a level can also be set on the base plate 6 during leveling). In addition, the length of the base plate 6 (0.5m in this example, and the actual effective length for calibration is 0.43m) is much smaller than the range of the pull rope sensor 5 to be calibrated (8m in this example), thus it can adapt to situations where the calibration space is limited.

[0056] The calibration device has a fixing position on the right side of the upper surface of the base plate 6. The fixing position is used to install the pull rope sensor 5 to be calibrated. A sensor mounting and positioning unit is fixed on the fixing position. The sensor mounting and positioning unit consists of a horizontally set pad and a vertically set plate on the pad. Mounting holes corresponding to the bottom positioning holes of the pull rope sensor 5 to be calibrated are opened on the vertical plate.

[0057] To accommodate different models, heights, and lengths of pull rope sensor products, the pads in this example are configured with various thicknesses. The pull rope sensor 5 to be calibrated is fixed in the fixed position by the pad of the corresponding thickness, ensuring that its outlet is at the preset height. In addition, it is worth noting that in this device, the pull rope sensor 5 to be calibrated is mounted laterally on a vertical plate. This is to avoid the wire rope tilting when pulled out of the outlet when installed horizontally, which would adversely affect the calibration accuracy.

[0058] The calibration device has a wire rope winding assembly on the left side of the base plate 6, which is used to pull out the wire rope of the wire rope sensor 5 to be calibrated at a constant speed during calibration and to collect the pulled-out wire rope. The wire rope winding assembly includes a wire rope collecting wheel 11 rotatably mounted on the base plate 6, a motor mounting plate 10 fixed on the base plate 6, and a stepper motor 1 fixedly mounted on the motor mounting plate 10 and whose output end rotates synchronously with the wire rope collecting wheel 11. The stepper motor 1 is connected to the host computer, and the host computer 1 controls the start, stop and speed of the stepper motor 1.

[0059] The radius and thickness of the wire rope take-up reel 11 are the same as those of the winding reel of the pull rope sensor 5 to be calibrated, and the structure is also roughly the same. In order to fix the pull ring 14 at one end of the wire rope, a notch is provided on the wire rope take-up reel 11 to hold the pull ring 14. The entrance position of the notch is at the same height in the vertical direction as the wire rope outlet of the pull rope sensor 5 to be calibrated.

[0060] The calibration device is also equipped with a high-precision length measuring component between the fixed position and the wire rope winding assembly. The high-precision length measuring component includes a clamping adjustment unit 16, a linear holding unit, a high-precision magnetic encoder 12, and a stable transmission unit. The structure and function of each unit of the wire rope winding assembly are described below.

[0061] The stable transmission unit includes an adapter plate 9, a length-recording wheel 8, and a bearing 15. In this example, the adapter plate 9 is circular, with multiple first and second screw holes respectively opened along its circumference. The adapter plate 9 is fixed to the outer edge of the magnetic encoder mounting hole in the middle of the base plate 6 by screws in conjunction with the first screw holes. The high-precision magnetic encoder 12 is set below the magnetic encoder mounting hole and is installed on the second screw hole of the adapter plate 9 by screws passing through the magnetic encoder mounting hole. The input shaft of the high-precision magnetic encoder 12 is vertically set at the center of the magnetic encoder mounting hole. The lower sleeve of the length-recording wheel 8 is fixedly sleeved on the input shaft of the high-precision magnetic encoder 12 to achieve synchronous transmission. A bearing 15 is provided between the central annular protrusion of the adapter plate 9 and the outer edge of the lower sleeve of the length-recording wheel 8 to ensure that the upper rotating part of the length-recording wheel 8 remains stable and does not wobble when it rotates.

[0062] The range of the high-precision magnetic encoder 12 is generally set to be more than 1.2 times the range of the rope sensor 5 to be calibrated. In this example, the range of the high-precision magnetic encoder 12 is 12m. If a rope sensor product with a larger range needs to be calibrated, the high-precision magnetic encoder 12 with a larger range can be directly replaced.

[0063] like Figure 5 and 6 As shown, the clamping adjustment unit 16 includes a clamping wheel 3 that cooperates with the length-counting wheel 8 to properly clamp the wire rope, a telescopic arm, and a support frame for supporting the telescopic arm. The support frame is U-shaped with an opening at the top. The clamping wheel 3 is rotatably mounted on the head of the telescopic arm. The tail of the telescopic arm passes through the upper part of the support frame and is clamped by a preload spring. Furthermore, the line connecting the rotation centers of the clamping wheel 3 and the length-counting wheel 8 is perpendicular to the wire rope. In addition, an elongated through hole is provided at the bottom of the support frame, through which the wire rope is fixed. The positioning hole on the base plate 6 allows for adjustment of the clamping force between the clamping wheel 3 and the length-recording wheel 8. A long, narrow through-hole is provided at the bottom of the support frame, and the position of the clamping wheel 3 can be finely adjusted using bolts and mounting holes on the base plate 6. This allows for adjustment of the distance (clamping force) between the clamping wheel 3 and the length-recording wheel 8. Additionally, multiple graduations can be engraved on the long hole to record the appropriate clamping force for the current model of the pull rope sensor, providing prior data for subsequent calibration of the same model and improving efficiency.

[0064] In this invention, both the clamping wheel 3 and the length-counting wheel 8 are made of polyurethane rubber to increase the coefficient of friction μ between them and the wire rope (in this example, the coefficient of friction μ is not less than 0.3). Alternatively, rubber coating can be applied to the sides of the clamping wheel 3 and the length-counting wheel 8. When configuring the gap and clamping force between the length-counting wheel 8 and the clamping wheel 3, in addition to keeping the wire rope straight, the following conditions must also be considered:

[0065] (1) Ensure smooth recovery: Static friction force f = μN < minimum recovery force F of the rope sensor coil spring. min卷 ;

[0066] (2) No relative slippage occurs between the wire rope and the counting wheel: the static friction force f > the force required to rotate the counting wheel f. 需 And ensure that the roundness and cylindricity of the wheel are both less than the corresponding error threshold (in this example, the wheel roundness ≤ 0.1mm and the cylindricity ≤ 0.05mm);

[0067] (3) To avoid slippage of the stepper motor during start / stop and excessive speed fluctuation during uniform rotation: the start / stop acceleration and the rate of change of speed fluctuation should be less than the static friction force f / the mass of the wire rope m (or the set acceleration threshold).

[0068] (4) The clamping force does not cause the wire rope to deform, nor does it cause the surface of the long pulley to deform: the clamping force N < the maximum force Nmax that causes extrusion deformation.

[0069] The linear holding unit includes guide wheels located on both sides of the stabilizing transmission unit and the clamping adjustment unit 16 along the wire rope tension and retraction direction. Figure 2 The diagram shows a first guide wheel 2 located on the side of the stabilizing transmission unit and clamping adjustment unit 16 near the wire rope winding assembly, and a second guide wheel 4 located on the side of the stabilizing transmission unit and clamping adjustment unit 16 near the rope sensor 5 to be calibrated. The first guide wheel 2 and the second guide wheel 4 are rotatably mounted on the base plate 6. Wire rope grooves are formed circumferentially on the side of the guide wheel to limit the wire rope. The depth of the wire rope groove is slightly larger than the diameter of the wire rope, and a ramp is provided at the groove opening to prevent the wire rope from coming out. In addition, by setting the positions of the first guide wheel 2 and the second guide wheel 4 on the base plate 6, the wire rope can be precisely pressed against the bottom of the corresponding wire rope groove of the guide wheel, which serves to limit the wire rope in both the horizontal and vertical directions. This ensures that the wire rope is stretched and retracted in a straight horizontal line, reducing the impact of wire rope straightness deviation on calibration accuracy.

[0070] like Figure 7 As shown in Figure a, in a feasible embodiment, since it is necessary to ensure that the wire rope between the second contact point b and the fourth contact point d remains straight during calibration, the first guide wheel 2 and the second guide wheel 4 are respectively positioned on both sides of the wire rope for limiting. In addition, considering that the winding radius of the wire rope take-up wheel 11 will gradually increase with the increase of the number of winding turns during the winding process, causing the fifth contact point e to extend outward and affecting the straightness of the wire rope, the first guide wheel 2 is located on the opposite side of the wire rope take-up wheel 11, while the second guide wheel 4 is located on the same side of the wire rope take-up wheel 11. During actual calibration, the wire rope generally has no pressure on the bottom of the wire rope groove of the second guide wheel 4 at the second contact point b, while the pressure on the bottom of the wire rope groove of the first guide wheel 2 at the fourth contact point d will increase with the increase of the number of winding turns.

[0071] like Figure 7 As shown in b, in another feasible embodiment, to further ensure that the wire rope stretching and retraction processes are both on a horizontal straight line and to prevent the influence of wire rope swaying, in this example, the first guide wheel 2 and the second guide wheel 4 are replaced with two pairs of guide wheels respectively. The structure of the guide wheels remains unchanged, but the depth of the wire rope groove is approximately the radius of the wire rope. Thus, each pair of guide wheels limits the wire rope through the wire rope groove opened circumferentially on the side of the wheel body. The wire rope is exactly close to the bottom of the wire rope groove of the pair of guide wheels, which effectively copes with the situation of swaying caused by the arrangement and winding of multiple turns of wire rope.

[0072] like Figure 7 As shown in c, in another feasible embodiment, further considering that during the winding process of the wire rope take-up wheel 11, the winding radius gradually increases with the increase of the number of winding turns, causing the fifth contact point e to extend outward and affecting the straightness of the wire rope, two first guide wheels 2 with identical structures are set in this example. They are both located on opposite sides of the wire rope take-up wheel 11, and the center line connecting the two first guide wheels 2 is parallel to the wire rope. The first first guide wheel closer to the wire rope take-up wheel 11 is used to limit the wire rope, and the pressure at its contact point d2 will increase and decrease as it moves away from the wire rope take-up wheel 11. The second first guide wheel of the wire rope take-up wheel 11 is used in conjunction with the second guide wheel 4 to achieve the straightness of the wire rope between the contact point d1 and the second contact point b. In addition, the distance between the second first guide wheel and the second guide wheel 4 is reduced compared to the two embodiments mentioned above. If the distance between the contact point d1 and the second contact point b is too long, it will affect the straightness of the wire rope. If it is too short, it will interfere with the high-precision magnetic encoder. Therefore, in this example, the distance between the contact point d1 and the second contact point b is set to be slightly larger than the circumference of the lengthening wheel 8 (about 1.05-1.1 times the circumference).

[0073] Combination Figure 7 As for a-7c, it is foreseeable that in practical calibration devices, considering the impact of cost, complexity, and calibration accuracy, different methods can be adopted respectively. Figure 7 The guide wheel setup shown in a-7c can also... Figure 7 The guide wheel setup schemes shown in a-7c can be combined in various ways to achieve the following: Figure 7 The setting method of the first guide wheel in C combined with Figure 7 The way the second guide wheel is set in b can also be combined with Figure 7 b and Figure 7 The first guide wheel in C is set up in such a way that it includes three guide wheels, one on the left and the other two on the right.

[0074] Furthermore, considering that during automatic calibration, to ensure calibration accuracy, the distance between two adjacent calibration points (i.e., the calibration interval) is generally chosen to be relatively small (generally 200mm-400mm). However, due to spatial constraints, the length of the wire rope pulled out (corrected length L0) during the process of the pull ring 14 being pulled out from the outlet of the wire rope sensor 5 to be calibrated and then hooked onto the wire rope storage wheel 11 will be greater than at least one time the calibration interval. Therefore, the first few calibration points may fail to be automatically calibrated. In view of this, this utility model adds multiple pull ring hanging points at corresponding positions on the base plate 6. Furthermore, each pull ring attachment point corresponds to a calibration point that cannot be automatically calibrated. When the pull ring 14 is attached to the first pull ring attachment point, the corresponding wire rope pull-out length is one calibration interval length. When the pull ring 14 is attached to the second pull ring attachment point, the corresponding wire rope pull-out length is two calibration interval lengths, and so on, until all calibration points that cannot be automatically calibrated are configured. To ensure the calibration accuracy of the pull ring attachment points, this utility model also marks the pull ring attachment points. Each model of pull rope sensor 5 to be calibrated corresponds to a corresponding pull ring attachment point and mark, so as to adapt to various models of pull rope sensor products.

[0075] like Figure 8 As shown, based on the above-mentioned draw-wire sensor calibration system, this utility model also provides a large-range, high-precision draw-wire sensor calibration method, which specifically includes the following steps:

[0076] 1) Install the pull rope sensor 5 to be calibrated laterally on the base plate 6, and connect the pull rope sensor 5 to be calibrated and the stepper motor 1 to the host computer for communication;

[0077] 2) Start and initialize the control and calibration program in the host computer, and start the automatic length calibration process;

[0078] 21) Configure the range L (i.e., the starting and ending points of the calibration), calibration interval Δl, and correction length L0 of the pull rope sensor 5 to be calibrated. The correction length L0 actually represents the length of the wire rope pulled out when the pull ring 14 is pulled out from the outlet of the pull rope sensor 5 to be calibrated until it is hooked onto the wire rope storage wheel 11. This distance needs to be measured in advance using a high-precision ruler. Each type of pull rope sensor corresponds to its own correction length L0.

[0079] 22) Forward and reverse range calibration:

[0080] 221) When the pull ring is in the initial position and is hooked onto the wire rope take-up reel 11, if the distance the wire rope is pulled out (calibration section) is greater than the calibration interval Δl, it indicates that automatic calibration of at least one calibration point cannot be achieved within this distance. Therefore, these calibration points that cannot be automatically calibrated need to be calibrated separately. Taking a range L of 8000mm, a correction length L0 of 410mm, and a calibration interval Δl of 200mm as an example, since L0>2Δl, there are two calibration points that need to be calibrated separately, namely 200mm and 400mm. At this time, the pull ring 14 is pulled out and hooked onto the pull ring hook points at 200mm and 400mm respectively, and the corresponding readings are taken. The output value of the fixed pull rope sensor 5 is recorded. After completing all individually calibrated calibration points, the pull ring 14 is attached to the attachment point of the wire rope take-up wheel 11. After adjusting the clamping adjustment unit 16 to clamp the wire rope, the stepper motor 1 is started to rotate forward to begin the automatic calibration of the positive range. At this time, the initial value of the high-precision magnetic encoder 12 is configured as the correction length L0. The stepper motor 1 is automatically controlled to step according to the set calibration interval Δl (for a calibration point of 600mm, the stepper motor 1 rotates by a length of 190mm, and for calibration points of 800mm and beyond, it steps according to the calibration interval Δl). The output value a of the pull rope sensor 5 to be calibrated corresponding to each calibration point in the positive range is recorded. n正 (In this example, there are a total of 41 output values, including the 0mm calibration point positive range);

[0081] 222) For reverse range calibration, the method is the same as for positive range calibration, but in reverse order. First, perform automatic calibration from 8000mm to 600mm. Then, remove the pull ring 14 from the attachment point of the wire rope take-up reel 11 and attach it to the pull ring attachment points at 400mm and 200mm respectively to complete the individual calibration. Record the output value a of the pull rope sensor 5 to be calibrated at each calibration point under reverse range. n反 (In this example, there are a total of 41 output values, including the 0mm calibration point reverse range);

[0082] 223) When the pull ring is in the initial position and is hooked onto the wire rope take-up wheel 11, the distance the wire rope is pulled out (calibrated section) is not greater than the calibration interval Δl. Then the pull ring can be directly hooked onto the hooking point of the wire rope take-up wheel 11, and the initial value of the high-precision magnetic encoder 12 is set to 0. The stepper motor 1 is controlled to step according to the set calibration interval Δl, and the output values ​​of the forward and reverse ranges at each calibration point are recorded respectively.

[0083] 23) Based on the recorded output values ​​of each calibration point in both forward and reverse ranges, calculate the average value as the final calibration value a for that calibration point. n (where n is the index of the calibration point), then we have an = a n正 +a n反 ;

[0084] 24) Linear interpolation is used to calibrate the length between two adjacent calibration points, and finally the calibration of the entire range is completed.

[0085] In summary, this invention provides a high-precision, large-range draw-wire sensor calibration system. Considering the limited space in calibration sites, this invention employs a calibration device with a wire rope take-up reel, a high-precision magnetic encoder, a linear holding unit, and a clamping adjustment unit. When calibrating large-range draw-wire sensors, the wire rope take-up reel simultaneously retracts the calibrated wire rope, reducing space requirements. Since the take-up reel can interfere with the wire rope in the calibration section during take-up, a linear holding unit with a guide wheel is included to keep the wire rope in the calibration section straight, ensuring high calibration accuracy. Furthermore, to prevent slippage of the wire rope during forward and reverse calibration, the calibration device also includes a clamping adjustment unit. Adjusting the distance and clamping force between the length-measuring wheel and the clamping wheel ensures that the clamping force on the wire rope is within a suitable range that prevents slippage and jamming, further improving calibration accuracy. Furthermore, considering that the wire rope length in the calibration section may exceed the calibration interval, preventing all calibration points from being automatically calibrated, this invention additionally incorporates a pull-ring attachment point method for manually pulling out and attaching uncalibrated calibration points. A correction length is also preset in the host computer to ensure accurate and automatic calibration of subsequent calibration points. Combined with the calibration system and method of this invention, the calibration device achieves an accuracy error within 4mm. For a wire rope sensor product with an 8000mm range, its equivalent accuracy is higher than 0.05%, meeting the calibration requirements of products with an accuracy requirement of 0.5%.

[0086] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A large-range, high-precision draw-wire sensor calibration system, comprising a calibration device and a host computer connected to the calibration device, characterized in that, The calibration device includes a base plate (6) and components respectively disposed on the base plate (6): Fixed position: used to achieve lateral positioning of the pull rope sensor (5) to be calibrated; Wire rope winding assembly: It is attached to the pull ring (14) of the pull rope sensor (5) to be calibrated, so as to pull out the wire rope through the pull ring (14) during calibration and to store the pulled-out wire rope. High-precision length measuring component: used to achieve high-precision calibration of the wire rope in the calibration section.

2. The large-range, high-precision draw-wire sensor calibration system according to claim 1, characterized in that, The fixed position is provided with a sensor installation and positioning unit, which consists of a horizontal pad and a vertical plate set on the pad. The pull rope sensor (5) to be calibrated is laterally fixed on the vertical plate.

3. The large-range, high-precision rope sensor calibration system according to claim 1, characterized in that, The wire rope winding assembly includes a wire rope storage wheel (11) rotatably mounted on a base plate (6), a motor mounting plate (10) fixed on the base plate (6), and a stepper motor (1) fixedly mounted on the motor mounting plate (10) and whose output end rotates synchronously with the wire rope storage wheel (11). The stepper motor (1) is connected to a host computer.

4. The large-range, high-precision draw-wire sensor calibration system according to claim 1, characterized in that, The high-precision length measuring component is set between the rope sensor (5) to be calibrated and the wire rope winding component. It includes a stable transmission unit, a high-precision magnetic encoder (12), a clamping adjustment unit (16), and a linear holding unit. The stable transmission unit includes an adapter plate (9) and a length measuring wheel (8). The adapter plate (9) is fixed at the outer edge of the magnetic encoder mounting hole in the middle of the base plate (6). The high-precision magnetic encoder (12) is set below the magnetic encoder mounting hole and fixed to the adapter plate (9). The output shaft is vertically set at the center of the magnetic encoder mounting hole. The length measuring wheel (8) is sleeved on the output shaft of the high-precision magnetic encoder (12).

5. A large-range, high-precision rope sensor calibration system according to claim 4, characterized in that, The clamping adjustment unit (16) includes a clamping wheel (3) that cooperates with the length-recording wheel (8) to clamp the wire rope, a telescopic arm for rotatably mounting the clamping wheel (3), and a support frame for supporting the telescopic arm. The telescopic arm provides clamping force through a spring, and the support frame adjusts its position on the base plate (6) through a strip hole at the bottom, thereby adjusting the distance and clamping force between the clamping wheel (3) and the length-recording wheel (8).

6. A large-range, high-precision draw rope sensor calibration system according to claim 5, characterized in that, The clamping force N between the clamping wheel (3) and the lengthening wheel (8) satisfies the following condition: (1) Ensure smooth recovery: Static friction force f = μN < minimum recovery force F of the rope sensor coil spring. min卷 μ is the coefficient of friction; (2) No relative slippage occurs between the wire rope and the counting wheel (8): the static friction force f > the force f required to drive the counting wheel (8) to rotate. 需 And note that the roundness and cylindricity of the long wheel (8) are both less than the corresponding error threshold; (3) Avoid the stepper motor (1) slipping during start / stop and slipping due to excessive speed fluctuation during uniform rotation: the start / stop acceleration and the rate of change of speed fluctuation during rotation are less than the static friction force f / the mass of the wire rope m; (4) The clamping force does not cause the wire rope to deform, nor does it cause the surface of the long pulley to deform: the clamping force N < the maximum force Nmax that causes extrusion deformation.

7. A large-range, high-precision draw rope sensor calibration system according to claim 4, characterized in that, The linear holding unit includes a first guide wheel (2) and a second guide wheel (4) that are rotatably mounted on the base plate (6) and have the same structure. The first guide wheel (2) is located between the clamping adjustment unit (16) and the wire rope winding assembly. The second guide wheel (4) is located between the clamping adjustment unit (16) and the pull rope sensor (5) to be calibrated. The first guide wheel (2) and the second guide wheel (4) have wire rope grooves on their sides for limiting the wire rope.

8. A large-range, high-precision draw-wire sensor calibration system according to claim 7, characterized in that, The first guide wheel (2) is provided on one side of the clamping wheel of the wire rope, and the second guide wheel (4) is provided on one side of the length counting wheel of the wire rope; Alternatively, two first guide wheels (2) are arranged side by side along the direction of the wire rope on one side of the clamping wheel of the wire rope, and one second guide wheel (4) is arranged on one side of the length counting wheel of the wire rope; Alternatively, one first guide wheel (2) may be installed on each side of the wire rope, and one second guide wheel (4) may be installed on each side of the wire rope.

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