High-precision pull cord sensor

Abstract

The application belongs to the technical field of pull rope sensors, and discloses a high-precision pull rope sensor, which comprises a shell assembly, a take-up assembly, a wire arranging assembly, a transmission assembly, a sensing and detecting assembly and a control circuit assembly. The take-up assembly is arranged inside the shell assembly, the outer periphery of the rotary part of the take-up assembly is wound with a steel wire rope, the elastic recovery part applies a rotary recovery force to the rotary part, the wire arranging assembly gradually corrects the direction of the steel wire rope to guide the steel wire rope to form an orderly winding on the rotary part, the sensing and detecting assembly converts the motion state transmitted by the transmission assembly into an electric signal, and the control circuit assembly comprises a control unit, a signal output unit and a feedback sampling unit. The control unit dynamically adjusts the output parameters of the signal output unit according to the deviation between the electric signal collection value collected by the feedback sampling unit and the target output value, so as to form a closed-loop calibration. The application effectively overcomes the temperature drift and element error through the closed-loop calibration, and has high output precision, good stability and long service life.

Description

Technical Field

[0001] This invention relates to the field of pull rope sensor technology, and in particular to a high-precision pull rope sensor. Background Technology

[0002] A pull-rope sensor is a detection device that converts linear displacement into a measurable electrical signal. Its core principle is to drive the mechanical transmission mechanism to rotate by pulling and releasing the rope, and then the sensing element converts the angular displacement into an electrical signal output. It is widely used in position and travel monitoring in machine tools, automated production lines, construction machinery, elevators and other scenarios.

[0003] Traditional draw-wire sensors typically use potentiometers or encoders as sensing elements, relying on the resistance changes of mechanical potentiometers to output signals. These sensors are highly susceptible to potentiometer wear, mechanical errors, and resistance nonlinearity, and are also prone to drift due to temperature variations. Existing encoder-based solutions mostly employ open-loop output without closed-loop calibration of the output signal, making it difficult to maintain high-precision output under harsh operating conditions.

[0004] To address this, a high-precision rope sensor is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a high-precision draw rope sensor, thereby solving or at least alleviating one or more of the problems mentioned above and other problems existing in the prior art.

[0006] To achieve the above objectives, the main technical solutions adopted by the present invention include: A high-precision pull-rope sensor, housing assembly, the housing assembly includes a main housing, the bottom of the main housing is open, a bottom cover is installed on the bottom of the main housing, and a bearing seat is provided on the top of the main housing; A take-up assembly is disposed inside the main housing. The take-up assembly includes a rotating part and an elastic return part. The outer periphery of the rotating part is used to wind the wire rope. The elastic return part is connected to the rotating part and is used to apply a rotational restoring force to the rotating part. A cable assembly is disposed inside the main housing and is used to correct the direction of the wire rope step by step to guide the wire rope to form an orderly winding on the rotating part. A transmission assembly, wherein the transmission assembly is used to transmit the rotational motion of the rotating part to the sensing and detection assembly; The sensing and detection component is used to convert the motion state transmitted by the transmission component into an electrical signal. A control circuit assembly includes a control unit, a signal output unit, and a feedback sampling unit. The control unit is electrically connected to the signal output terminal of the sensing and detection assembly, and the output terminal of the control unit is electrically connected to the input terminal of the signal output unit. The signal output unit is used to output an electrical signal representing the displacement. The input terminal of the feedback sampling unit is electrically connected to the output terminal of the signal output unit, and the output terminal of the feedback sampling unit is electrically connected to the feedback input terminal of the control unit. The control unit is used to dynamically adjust the output parameters of the signal output unit based on the deviation between the electrical signal acquisition value collected by the feedback sampling unit and the target output value, thus forming a closed-loop calibration.

[0007] According to a high-precision draw rope sensor of the present invention, the rotating part includes a reel body and a drive shaft. One end of the wire rope is wound around the reel body, and the other end of the wire rope passes through the side wall of the main housing and is connected to a wire buckle after being guided by the wire laying assembly. The reel body is disposed on the drive shaft, and a bearing is sleeved on the drive shaft. An insert sleeve is embedded inside the bearing seat, and the outer ring of the bearing is installed in the insert sleeve.

[0008] According to a high-precision draw rope sensor of the present invention, the elastic recovery part includes a reel frame, which is disposed inside the main body of the reel. A shaft is rotatably disposed in the middle of the reel frame. The lower end of the drive shaft is installed inside the upper end of the shaft. Reel covers are installed at the top and bottom of the reel frame. The reel cover at the bottom is fixedly connected to the bottom cover. Coil springs are provided at the top and bottom of the reel frame. The inner end of the coil spring is fixedly connected to the shaft, and the outer end of the coil spring is fixedly connected to the inner wall of the reel frame. A positioning shaft is embedded in the upper end of the bottom cover. The upper end of the positioning shaft is rotatably inserted into the lower end of the shaft.

[0009] According to a high-precision draw rope sensor of the present invention, the transmission assembly includes a worm and a worm wheel, the worm is disposed at the upper end of the transmission shaft, the worm wheel meshes with the worm, and a gap compensation assembly is provided on the top of the main housing, the worm wheel being rotatably mounted on the gap compensation assembly.

[0010] According to a high-precision draw rope sensor of the present invention, the gap compensation assembly includes a mounting sleeve, which is rotatably mounted on the main housing. The outer wall of the mounting sleeve is provided with a mounting bracket, and a connecting shaft is rotatably mounted on the mounting bracket. A worm gear is located at one end of the connecting shaft. A limiting block is provided at the top of the main housing, and a torsion spring is sleeved on the limiting block. The lower end of the torsion spring abuts against the main housing, and the upper end of the torsion spring abuts against the lower end of the mounting bracket.

[0011] According to a high-precision draw rope sensor of the present invention, the sensing and detection assembly includes a magnet and a Hall sensor. The magnet is installed at the end of the connecting shaft away from the worm gear. A mounting plate is installed on the side of the mounting bracket away from the worm gear. A Hall sensor is installed on the side of the mounting plate close to the magnet. The Hall sensor is electrically connected to the signal input terminal of the control unit.

[0012] According to a high-precision cable sensor of the present invention, the cable assembly includes a plurality of support rods arranged along the outer periphery of the cable reel body, the support rods are mounted on the bottom cover, and a guide sleeve is rotatably sleeved on the support rod. The guide sleeve is slidable up and down along the height direction of the support rod, and the guide sleeve is provided with a guide wheel for guiding the wire rope.

[0013] According to a high-precision draw rope sensor of the present invention, a top cover is installed on the top of the main housing, and the control circuit assembly, gap compensation assembly, transmission assembly and sensing and detection assembly are all located inside the top cover.

[0014] In a high-precision draw-wire sensor according to the present invention, the closed-loop calibration is continuously performed by the control unit according to a preset control cycle, specifically including the following steps: S1, The control unit reads the angle signal currently acquired by the sensing and detection component. And according to the angle signal The current displacement L is calculated based on the effective radius R of the rotating component, and then the target output value corresponding to the current displacement L is determined. ,in ; S2, the control unit based on the current PWM duty cycle A PWM signal is generated and output to the signal output unit, which converts the PWM signal into an electrical signal. Output, where This represents the PWM duty cycle in the k-th control cycle. and Proportional, and ,in The reference voltage of the signal output unit is used; the control unit achieves precise control of the output voltage by adjusting the duty cycle of the PWM signal. S3, the feedback sampling unit collects the electrical signal value currently actually output by the signal output unit. and the electrical signal acquisition value The data is transmitted back to the control unit; the sampling accuracy of the feedback sampling unit is affected by its operating voltage. The influence of electrical signal acquisition values Compared with the actual output value The relationship between them satisfies: in The reference voltage of the feedback sampling unit. The actual operating voltage of the feedback sampling unit; The control unit monitors the actual operating voltage of the feedback sampling unit in real time during the closed-loop calibration process. And by reverse-engineering the above relationship, the actual output value is obtained. This is to eliminate the acquisition error introduced by the operating voltage fluctuation of the feedback sampling unit; S4. The control unit outputs the actual value. As a benchmark, calculate its relationship with the target output value. deviation value ,in ; S5. The control unit determines whether the absolute value of the deviation value |e(k)| is greater than a preset threshold. ,like Then, based on the aforementioned deviation value The sign and magnitude of the signal determine the adjustment direction and step size, and the PWM duty cycle is updated according to the following formula: ; in This is the proportionality coefficient. The integral coefficient is... The differential coefficients are... Update the PWM duty cycle and return S2; if If the current PWM duty cycle remains unchanged, the closed-loop calibration of the current control cycle will end.

[0015] In a high-precision pull-string sensor according to the present invention, a sealing gasket is provided between the bottom cover and the main housing.

[0016] The present invention has at least the following beneficial effects: Using Hall sensors as sensing elements to replace traditional potentiometers or encoders, Hall sensors achieve non-contact angle detection by generating magnetic field changes through magnet rotation. There is no mechanical contact or friction wear, avoiding the accuracy decay and shortened lifespan problems caused by carbon brush wear in traditional potentiometers. It has the advantages of long service life and high reliability. By setting up a control unit and a feedback sampling unit, the control unit collects the electrical signal values ​​retrieved by the feedback sampling unit. With target output value deviation By dynamically adjusting the output parameters of the signal output unit, a closed-loop calibration of the internal signal chain of the sensor is formed. Compared with the existing open-loop output scheme of the encoder, the closed-loop calibration can correct the output drift caused by temperature changes and component errors in real time, effectively overcome the influence of temperature drift and component errors on output accuracy, and enable the sensor to maintain high-precision output throughout the entire operating temperature range and the entire life cycle, significantly improving the measurement stability and reliability of the sensor under harsh working conditions.

[0017] The actual operating voltage of the feedback sampling unit is monitored in real time by the control unit. and according to the formula The collected values ​​are corrected in real time, so as to Alternative Deviation value The calculation eliminates the acquisition error introduced by the feedback sampling unit due to operating voltage fluctuations. This voltage correction mechanism effectively avoids the impact of power supply voltage fluctuations in industrial settings on measurement accuracy, further improving the sensor's output accuracy and anti-interference capability in complex power supply environments.

[0018] The PWM duty cycle is controlled by the control unit. With precise control and a second-order low-pass filter, the digital domain PWM signal is converted into a high-precision analog voltage signal output. Compared with the traditional potentiometer voltage divider output scheme, it has the advantages of high output accuracy, good linearity, and software-configurable range. At the same time, it is easy to expand different output protocols and ranges through firmware upgrades. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is one of the partial structural schematic diagrams of the present invention; Figure 3 This is one of the schematic diagrams of a partial explosion structure of the present invention; Figure 4 This is the second schematic diagram of the partial explosion structure of the present invention; Figure 5 This is a schematic diagram of the cable assembly of the present invention; Figure 6 This is a partial cross-sectional structural diagram of the present invention; Figure 7 This is a schematic diagram of the main housing of the present invention; Figure 8 This is a circuit block diagram of the control circuit assembly of the present invention; Figure 9 This is one of the schematic diagrams showing the arrangement dimensions of the guide wheels in this invention; Figure 10 This is the second schematic diagram showing the arrangement dimensions of the guide wheels in this invention; Figure 11 This is the third schematic diagram showing the arrangement dimensions of the guide wheels in this invention; Figure 12 This is the fourth schematic diagram showing the arrangement dimensions of the guide wheels in this invention; Figure 13 This is the fifth schematic diagram showing the arrangement dimensions of the guide wheels in this invention.

[0020] Explanation of icon numbers: 1. Housing assembly; 101. Bottom cover; 102. Main housing; 1021. Bearing seat; 1022. Limiting block; 103. Top cover; 104. Sealing gasket; 2. Transmission assembly; 201. Worm gear; 202. Worm wheel; 3. Take-up assembly; 301. Reel body; 302. Reel frame; 303. Reel cover; 304. Shaft core; 305. Coil spring; 306. Positioning shaft; 307. Transmission shaft; 308. Bearing; 309. Insert sleeve; 4. Clearance compensation assembly; 401. Mounting sleeve; 402. Mounting bracket; 403. Connecting shaft; 404. Torsion spring; 405. Assembly plate; 5. Sensing and detection assembly; 501. Magnet; 502. Hall sensor; 6. Steel wire rope; 601. Cable clip; 7. Cable assembly; 701. Support rod; 702. Guide sleeve; 703. Guide wheel; 8. Control circuit assembly; 801. Control unit; 802. Signal output unit; 803. Feedback sampling unit; 804. Watchdog circuit; 805. Protection unit; 806. DC-DC converter unit; 807. Low dropout linear regulator unit. Detailed Implementation

[0021] The following will describe in detail the implementation of this application with reference to the accompanying drawings and embodiments, so that the implementation process of how this application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0022] like Figures 1 to 13 As shown, the present invention provides a high-precision rope sensor, which mainly includes a housing assembly 1, a transmission assembly 2, a wire take-up assembly 3, a gap compensation assembly 4, a sensing and detection assembly 5, a wiring assembly 7, and a control circuit assembly 8.

[0023] The housing assembly 1 includes a main housing 102, a bottom cover 101, and a top cover 103. The main housing 102 has a cylindrical structure with an opening at the bottom and a bearing seat 1021 at the top. A limiting block 1022, a cylindrical boss integrally formed on the top of the main housing 102, is also provided on the top of the main housing 102 for mounting a torsion spring 404. A cable outlet hole is provided on the side wall of the main housing 102 for the steel wire rope 6 to pass through.

[0024] The bottom cover 101 is installed on the bottom of the main housing 102 by screws, sealing the bottom opening of the main housing 102. A sealing gasket 104 is provided between the bottom cover 101 and the main housing 102. The sealing gasket 104 is made of silicone rubber, and its shape matches the mating surface shape of the bottom cover 101 and the main housing 102. The sealing gasket 104 is embedded in a sealing groove opened on the upper end face of the bottom cover 101. The sealing gasket 104 prevents external dust, moisture and other debris from entering the interior of the main housing 102, ensuring the cleanliness and normal operation of the internal components of the sensor.

[0025] A positioning shaft 306 is embedded in the center of the upper end of the bottom cover 101. The positioning shaft 306 is a cylindrical shaft structure. The lower end of the positioning shaft 306 is installed in the mounting hole at the upper end of the bottom cover 101. The upper end of the positioning shaft 306 is used to rotatably insert into the center hole at the lower end of the shaft core 304, providing rotational support for the lower end of the shaft core 304.

[0026] The top cover 103 is mounted to the top of the main housing 102 with screws. A sealing ring is provided between the top cover 103 and the main housing 102 to ensure sealing performance. The control circuit assembly 8, the gap compensation assembly 4, the transmission assembly 2, and the sensing and detection assembly 5 are all located inside the top cover 103, which seals and protects these internal components. The top cover 103 is also provided with a connector interface for leading the output signal of the signal output unit 802 to an external device.

[0027] In this embodiment, the take-up assembly 3 is disposed inside the main housing 102, and the take-up assembly 3 includes a rotating part and an elastic recovery part.

[0028] Specifically, the rotating part includes a coil body 301 and a drive shaft 307. The coil body 301 is a one-piece aluminum alloy structure, in the shape of a disc, used to accommodate the wire rope 6 for orderly winding. A shaft hole is provided in the center of the coil body 301, through which the coil body 301 is mounted on the drive shaft 307, ensuring synchronous rotation between the coil body 301 and the drive shaft 307. One end of the wire rope 6 is wound in the rope groove on the outer periphery of the coil body 301, and the other end of the wire rope 6 is guided by the cable laying assembly 7 and passes through the cable outlet hole on the side wall of the main housing 102, and is connected to a cable buckle 601. The cable buckle 601 is used to connect with an external moving part to be measured.

[0029] A bearing 308, which is a deep groove ball bearing, is fitted into the middle of the drive shaft 307. An insert sleeve 309, made of copper alloy, is embedded inside the bearing housing 1021 of the main housing 102. The outer ring of the bearing 308 is mounted inside the insert sleeve 309, and the inner ring of the bearing 308 is mounted on the drive shaft 307. The bearing 308 enables the drive shaft 307 to rotate smoothly relative to the main housing 102.

[0030] The elastic recovery unit includes a disc frame 302, a shaft core 304, a disc cover 303, and a coil spring 305. The disc frame 302 is located inside the main body 301 of the reel. A shaft core 304 is rotatably mounted in the center of the disc frame 302. The shaft core 304 is a cylindrical shaft structure with an upper mounting hole and a lower positioning hole at its center. The lower end of the drive shaft 307 is installed in the upper mounting hole inside the shaft core 304. Disc covers 303 are installed at both the top and bottom of the disc frame 302. The bottom disc cover 303 is fixedly connected to the bottom cover 101 with screws, thus enabling the installation of the disc frame 302.

[0031] Both the top and bottom of the tray frame 302 are equipped with coil springs 305. The coil springs 305 are made of high-fatigue-life spring steel strip and have a planar spiral spring structure. The inner end of the coil spring 305 has an inner hook, and the outer wall of the shaft core 304 has a corresponding inner hook groove. The inner hook of the coil spring 305 engages with the inner hook groove of the shaft core 304, achieving a fixed connection between the inner end of the coil spring 305 and the shaft core 304. The inner wall of the tray frame 302 has a corresponding outer hook groove, and the outer end of the coil spring 305 has an outer hook. The outer hook of the coil spring 305 engages with the outer hook groove of the tray frame 302, achieving a fixed connection between the outer end of the coil spring 305 and the inner wall of the tray frame 302.

[0032] The upper end of the positioning shaft 306 is rotatably inserted into the lower positioning hole of the shaft core 304. A bearing is provided between the positioning shaft 306 and the lower positioning hole of the shaft core 304 to provide rotational support for the lower end of the shaft core 304 and ensure the concentricity of the rotation of the shaft core 304 and the transmission shaft 307.

[0033] When the shaft core 304 rotates with the drive shaft 307, the inner end of the coil spring 305 follows the rotation of the shaft core 304, while the outer end is fixed to the stationary coil frame 302. The coil spring 305 undergoes torsional deformation, accumulating elastic potential energy. When the external force on the wire rope 6 is released, the coil spring 305 releases its elastic potential energy, driving the shaft core 304 to rotate in the opposite direction, thereby causing the drive shaft 307 and the coil body 301 to rotate in the opposite direction to achieve automatic rewinding of the wire rope 6.

[0034] In this embodiment, the transmission assembly 2 includes a worm 201 and a worm wheel 202. The worm 201 is connected to the upper end of the transmission shaft 307 via a key. When the transmission shaft 307 rotates, it drives the worm 201 to rotate synchronously. The worm wheel 202 meshes with the worm 201, and the rotational motion of the worm 201 is transmitted to the worm wheel 202, where it is reduced in speed before being output. The worm wheel 202 is rotatably mounted on the connecting shaft 403 of the clearance compensation assembly 4. The meshing center distance between the worm 201 and the worm wheel 202 is determined by the installation position of the clearance compensation assembly 4.

[0035] Specifically, in this embodiment, the clearance compensation component 4 is disposed on the top of the main housing 102 to eliminate the meshing clearance between the worm 201 and the worm wheel 202. The clearance compensation component 4 includes a mounting sleeve 401, a mounting bracket 402, a connecting shaft 403, and a torsion spring 404.

[0036] The mounting sleeve 401 is rotatably mounted on the main housing 102, and the mounting sleeve 401 can rotate freely about its axis relative to the main housing 102. The outer wall of the mounting sleeve 401 is provided with a mounting bracket 402, which rotates synchronously with the mounting sleeve 401. The mounting bracket 402 has a shaft hole, and the connecting shaft 403 is rotatably mounted in the shaft hole through a bearing. The connecting shaft 403 can rotate freely about its own axis relative to the mounting bracket 402.

[0037] The worm gear 202 is connected to one end of the connecting shaft 403 by a key, and the worm gear 202 rotates synchronously with the connecting shaft 403.

[0038] A torsion spring 404 is fitted onto the limiting block 1022. The lower end of the torsion spring 404 is bent and engaged with the main housing 102, ensuring that the lower end of the torsion spring 404 abuts against the main housing 102. The upper end of the torsion spring 404 is bent and abuts against the lower end face of the mounting bracket 402. The torsion spring 404 is pre-torsed at a certain angle during assembly to provide a stable preload. The torsion spring 404 applies a continuous torsional force to the mounting bracket 402, pushing the mounting bracket 402 to rotate around the axis of the mounting sleeve 401, thereby ensuring that the worm gear 202 always presses against the worm 201, eliminating the meshing clearance between the worm 201 and the worm gear 202, and guaranteeing the smoothness and accuracy of the transmission.

[0039] In this embodiment, the sensing and detection component 5 includes a magnet 501 and a Hall sensor 502. The magnet 501 is mounted on the end of the connecting shaft 403 away from the worm gear 202. The magnet 501 rotates synchronously with the connecting shaft 403.

[0040] Mounting plate 405, a flat plate structure, is screwed onto the side of mounting bracket 402 away from worm gear 202. Hall sensor 502 is mounted on the side of mounting plate 405 closest to magnet 501. Hall sensor 502 is surface-mounted onto the PCB of mounting plate 405. The axial clearance between Hall sensor 502 and magnet 501 is 1 mm to 3 mm. Hall sensor 502 communicates with control unit 801 via SPI bus, transmitting angle signals to control unit 801 in digital form.

[0041] When the connecting shaft 403 rotates, the magnet 501 rotates accordingly, and the direction of the magnetic field around the magnet 501 changes accordingly. The Hall sensor 502 detects the change in the magnetic field generated by the rotation of the magnet 501 and converts the angular displacement into an electrical signal.

[0042] In this embodiment, the cable assembly 7 is disposed inside the main housing 102. Preferably, there are three support rods 701, distributed along the outer periphery of the cable reel body 301. The lower end of each support rod 701 is threadedly connected to the bottom cover 101, while the upper end is a free end. Each support rod 701 is rotatably fitted with a guide sleeve 702. The inner wall of the guide sleeve 702 and the outer wall of the support rod 701 are in sliding fit, allowing the guide sleeve 702 to slide up and down along the height of the support rod 701 and rotate around its axis. The outer wall of the guide sleeve 702 has an integrally formed annular flange. A guide wheel 703 is provided on the guide sleeve 702, with an arc-shaped rope guide groove on its outer periphery. The arc of the groove matches the diameter of the wire rope 6 to ensure stable operation of the wire rope 6 on the guide wheel 703. Multiple guide wheels 703 form a continuous guide channel.

[0043] When the wire rope 6 is released or retracted from the reel body 301, the wire rope 6 is guided by the arc-shaped guide groove of the guide wheel 703. The guide wheel 703 rotates under the friction of the wire rope 6, while the guide sleeve 702 slides up and down along the height direction of the support rod 701, so that the wire rope 6 is wound layer by layer in an orderly manner on the reel body 301 in the axial direction, avoiding random winding and overlapping.

[0044] In order to achieve a single-layer uniform arrangement of the wire rope 6 on the main body 301 of the wire reel, the arrangement dimensions of the guide wheel 703 of the wire laying assembly 7 are designed as follows in this embodiment.

[0045] Define the following dimensional parameters: the diameter of the coil body 301 is... The diameter of wire rope 6 is The winding diameter of wire rope 6 is The winding diameter The size is related to the number of overlapping layers, and satisfies , where n is the number of overlapping layers. In the ideal case of a single-layer arrangement, the winding diameter is... Define the effective width of the coil body 301 as... The distance between the inlet / outlet of the steel wire rope 6 and the upper part of the main body 301 of the wire reel is The distance between the inlet / outlet of the steel wire rope 6 and the lower part of the main body of the wire reel 301 is... The horizontal distance between the wire rope inlet / outlet 6 and the main body of the reel is 301. .

[0046] Define the offset angle of wire rope 6 as and ,in , The best solution is That is, the cable outlet is located at the center of the cable reel body 301 in the width direction. At this time The offset angles of the wire rope 6 on both the upper and lower sides in the width direction are symmetrical and equal, which helps to ensure that the wire rope 6 is subjected to uniform force during the reciprocating winding process.

[0047] Define the angle of offset of wire rope 6 in the width direction as . to .in The size depends on the size of the cable outlet and the safe distance between the cable outlet and the surrounding structure. to The size depends on the groove width of the guide wheel 703, the angle of the guide wheel 703, the bottom radius of the guide wheel 703, and the diameter of the wire rope 6.

[0048] Define the center distance between the cable outlet and the first guide wheel 703 as: The center distance between adjacent guide wheels 703 is and The center distance between the last guide wheel 703 and the main body of the reel 301 is .

[0049] Based on the above dimensional parameters, the ribbon cable assembly 7 in this embodiment satisfies the following dimensional relationships: The length of a single turn of the steel wire rope (6 loops) is: In the ideal case of a single-layer arrangement: The sensor measures the length as Total number of turns of wire rope 6 satisfy: The number of turns N that the steel wire rope 6 can be wound in a single layer on the main body 301 of the wire reel satisfies: This formula represents the ideal situation, where the steel wire ropes 6 are tightly packed together without gaps.

[0050] The number of overlay layers n satisfies: This formula represents the ideal situation, where each layer can be filled.

[0051] When using guide wheel 703, the total angle that the wire rope 6 can deflect is A single-layer uniform arrangement can be achieved if the following conditions are met: Without using the guide wheel 703, the maximum offset angle of the wire rope 6 is only The following conditions must be met to achieve a uniform single-layer arrangement: Through the constraints of the above-mentioned dimensional relationships, the wire rope assembly 7 can ensure that the offset angle of the wire rope 6 during the winding process is always within the range that the guide wheel 703 can correct, thereby achieving a single-layer uniform arrangement of the wire rope 6 on the main body of the wire reel 301.

[0052] In this embodiment, the control circuit assembly 8 is disposed inside the main housing 102, located inside the upper cover 103. The control circuit assembly 8 includes a control unit 801, a signal output unit 802, a feedback sampling unit 803, a watchdog circuit 804, a protection unit 805, a DC-DC converter unit 806, and a low-dropout linear regulator unit 807.

[0053] The control unit 801 uses an STM32F103 series microcontroller with an ARM Cortex-M3 core and a 72MHz clock speed. It integrates multiple timers for generating PWM signals and multiple 12-bit successive approximation ADC channels for acquiring voltage signals. The control unit 801 communicates with the Hall sensor 502 via an SPI bus to read angle signals. The PWM output terminal of the control unit 801 is connected to the input terminal of the signal output unit 802.

[0054] The signal output unit 802 employs a signal conditioning circuit that includes a second-order low-pass filter and an operational amplifier. The reference voltage of the signal output unit 802... It is 5V.

[0055] The feedback sampling unit 803 employs a sampling circuit that includes a voltage divider resistor network and an analog-to-digital converter (ADC). The voltage divider resistor network divides the 0V to 5V analog voltage signal output from the signal output unit 802 to the ADC input range of the control unit 801. The ADC uses a 12-bit successive approximation ADC integrated within the control unit 801, with a sampling rate set to 100kHz and a sampling window equal to the average of 10 consecutive sampling points to suppress high-frequency noise. The reference voltage of the feedback sampling unit 803... The voltage is 4.096V, provided by a precision voltage reference source, with a temperature coefficient of 10ppm / ℃. The output of the feedback sampling unit 803 is connected to the ADC input of the control unit 801.

[0056] The output of the watchdog circuit 804 is connected to the reset terminal of the control unit 801. The watchdog circuit 804 is used to monitor the operating status of the control unit 801. When the control unit 801 is working normally, it periodically sends a feed signal to the watchdog circuit 804. When the control unit 801 program crashes or freezes, causing the feed signal to time out and not be updated, the watchdog circuit 804 outputs a reset signal to the reset terminal of the control unit 801, forcing the control unit 801 to reset and restart.

[0057] The input terminal of the protection unit 805 is connected to an external power supply, and the output terminal of the protection unit 805 is connected to the input terminal of the DC-DC converter 806. The protection unit 805 adopts a three-stage protection circuit. The first stage is a transient voltage suppression diode, which is used to suppress transient overvoltage surges on the power supply line; the second stage is a reverse connection protection diode, which is used to prevent circuit damage caused by reverse polarity of the power supply; and the third stage is a varistor, which is used to clamp the input voltage within a safe range.

[0058] The DC-DC converter 806 employs a switching buck converter. The input of the DC-DC converter 806 is connected to the output of the protection unit 805. The output of the DC-DC converter 806 is connected to the power input of the signal output unit 802, the power input of the feedback sampling unit 803, the input of the low-dropout linear regulator unit 807, and the power input of the watchdog circuit 804, respectively. The DC-DC converter 806 converts the external input voltage, protected by the protection unit 805, into a stable 5V DC voltage to power the signal output unit 802.

[0059] The low-dropout linear regulator unit 807 employs a low-dropout linear regulator. The input terminal of the low-dropout linear regulator unit 807 is connected to the output terminal of the DC-DC converter unit 806, and the output terminal of the low-dropout linear regulator unit 807 is connected to the power input terminals of the control unit 801 and the Hall sensor 502. The low-dropout linear regulator unit 807 is used to convert the 5V DC voltage output by the DC-DC converter unit 806 into a stable 3.3V DC voltage to power the control unit 801 and the Hall sensor 502.

[0060] The electrical connections between the units are as follows: The signal output terminal of Hall sensor 502 is electrically connected to the SPI interface of control unit 801 via the SPI bus. The PWM output pin of control unit 801 is electrically connected to the input terminal of signal output unit 802. The output terminal of signal output unit 802 serves as the analog voltage output terminal of the entire sensor and is also electrically connected to the input terminal of feedback sampling unit 803. The output terminal of feedback sampling unit 803 is electrically connected to the ADC input terminal of control unit 801. The input terminal of protection unit 805 is connected to the positive and negative terminals of external power supply, and the positive and negative terminals of the output terminal of protection unit 805 are respectively connected to the positive and negative terminals of the input terminal of DC-DC converter unit 806. The positive terminal of the output terminal of DC-DC converter unit 806 is connected to the positive power supply terminal of signal output unit 802 and the positive input terminal of low dropout linear regulator unit 807. The positive terminal of the output terminal of low dropout linear regulator unit 807 is connected to the positive power supply terminal of control unit 801 and the positive power supply terminal of Hall sensor 502. The grounding terminals of all units are connected to a common ground.

[0061] The closed-loop calibration is continuously performed by the control unit 801 according to a preset control cycle. In this embodiment, the preset control cycle is set to 10 milliseconds, meaning that the control unit 801 executes a complete closed-loop calibration process every 10 milliseconds. The specific steps are as follows: S1, Control Unit 801 reads the angle signal collected by Hall sensor 502 via SPI bus. The Hall sensor 502 has a 14-bit resolution and an angle measurement accuracy of ±0.5 degrees. The control unit 801 stores the effective radius R of the rotating component in its internal memory; this effective radius R is 25 mm, obtained through factory calibration. The control unit 801 then uses the formula... Calculate the current linear displacement L of wire rope 6. Target output value. There is a linear correspondence with the displacement L, with the following correspondence: 0 mm displacement corresponds to 0 V output voltage, 500 mm displacement corresponds to 5 V output voltage, and intermediate points are calculated by linear interpolation.

[0062] S2, Control unit 801 based on the current PWM duty cycle A PWM signal is generated. The timer of the control unit 801 is configured in PWM mode, and the PWM frequency is set to 20kHz, which is above the range of human hearing to avoid audible noise, while also meeting the response bandwidth requirements of the signal output unit 802. The PWM signal is filtered by a second-order low-pass filter in the signal output unit 802 to remove high-frequency components, and then amplified proportionally by an operational amplifier to output an analog voltage signal. , and Proportional, satisfying ,in The reference voltage for the signal output unit 802 is 5V; The control unit 801 also performs PWM duty cycle limiting processing, The duty cycle is limited to the range of 0.05 to 0.95 to avoid the non-linear operation of the signal output unit 802 caused by excessively small or large duty cycles.

[0063] S3, the feedback sampling unit 803 acquires the current actual output electrical signal value of the signal output unit 802 through its internal voltage divider resistor network and analog-to-digital conversion circuit. and the electrical signal acquisition value The data is fed back to control unit 801. The analog-to-digital conversion circuit uses a 12-bit successive approximation ADC with a sampling rate of 100kHz and a sampling window that is the average of 10 consecutive sampling points to suppress high-frequency noise. The reference voltage of the feedback sampling unit 803... It is 4.096V.

[0064] The sampling accuracy of the feedback sampling unit 803 is affected by its operating voltage. The influence of electrical signal acquisition values Compared with the actual output value The relationship between them satisfies: Control unit 801 monitors the actual operating voltage of feedback sampling unit 803 in real time. The voltage is divided by a precision resistor and then fed into an ADC channel of the control unit 801 for real-time acquisition. Control unit 801 monitors the actual operating voltage of feedback sampling unit 803 in real time during closed-loop calibration. And by reverse-engineering the above relationship, the actual output value is obtained. This is to eliminate the acquisition error caused by the operating voltage fluctuation of the feedback sampling unit 803; S4, Control Unit 801 outputs the actual value As a baseline, calculate its relationship with the target output value. deviation value ,in ; S5. Control unit 801 determines whether the absolute value of the deviation |e(k)| is greater than a preset threshold. ,like Then based on the deviation value The sign and magnitude determine the adjustment direction and step size, and the PWM duty cycle is updated according to the following formula: ; in This is the proportionality coefficient. The integral coefficient is... The differential coefficients are... Update the PWM duty cycle and return S2; if If the current PWM duty cycle remains unchanged, the closed-loop calibration of the current control cycle will end.

[0065] Control unit 801 follows the relationship in S3 The actual output value is obtained by reverse engineering. ,by Alternative It participates in the calculation of the deviation value e(k) in S4. When During the descent, the collected value Too high, multiply by a coefficient Perform downward correction to restore the true output value; when As it rises, the collected value Too low, multiply by a coefficient Make an upward correction.

[0066] The above corrections effectively eliminate the acquisition error caused by operating voltage fluctuations in the feedback sampling unit 803.

[0067] Working principle In the initial state, the wire rope 6 is fully retracted under the elastic restoring force of the coil spring 305, and the main body of the spool 301 is in the initial position. At this time, the worm gear 201 and the worm wheel 202 are tightly meshed under the preload of the torsion spring 404.

[0068] When the external moving part being measured is displaced, the wire rope 6 is pulled by the wire buckle 601. The wire rope 6 is released from the reel body 301 by the arc-shaped guide groove of the guide wheel 703. The wire rope 6 pulls the reel body 301 to rotate against the elastic restoring force of the coil spring 305, and the reel body 301 drives the drive shaft 307 to rotate synchronously. When the drive shaft 307 rotates, it drives the worm gear 201 to rotate synchronously, and the worm gear 201 drives the worm wheel 202 meshing with it to rotate. The worm wheel 202 drives the connecting shaft 403 to rotate, and the magnet 501 at the end of the connecting shaft 403 rotates synchronously accordingly.

[0069] Hall sensor 502 detects changes in the magnetic field generated by the rotation of magnet 501 and converts angular displacement into an angular signal. The signal is transmitted to the control unit 801 via the SPI bus. The control unit 801 then processes the received angle signal. And the effective radius R of the rotating part, according to the formula Calculate the current displacement L of the wire rope, and determine the target output voltage value based on the displacement. .

[0070] Control unit 801 based on the current PWM duty cycle A PWM signal is generated and output to the signal output unit 802, which converts the PWM signal into a smooth analog voltage signal for output. The feedback sampling unit 803 acquires the actual voltage value output by the signal output unit 802 in real time. The data is then transmitted back to control unit 801. Control unit 801 calculates the deviation value. If the absolute value of the deviation is greater than the preset threshold Then, the PWM duty cycle is updated according to the PID formula to make the electrical signal acquisition value approach the target value.

[0071] During this process, the control unit 801 monitors the actual operating voltage of the feedback sampling unit 803 in real time. ,when When the deviation from the nominal value by more than ±0.1V exceeds 5V, follow the formula. The acquired values ​​are corrected to eliminate acquisition errors introduced by operating voltage fluctuations. The processes S1 to S5 described above are repeated in each preset control cycle, ensuring that the electrical signal acquisition values ​​continuously track the target output value across the entire operating temperature range and throughout the entire lifespan.

[0072] When the external moving part to be measured moves in the opposite direction, the traction force of the wire rope 6 decreases or is released, the coil spring 305 releases elastic potential energy to drive the shaft core 304 to rotate in the opposite direction, the shaft core 304 drives the transmission shaft 307 and the coil body 301 to rotate in the opposite direction, and the wire rope 6 is automatically retracted under the drive of the coil spring 305, and is guided by the guide wheel 703 to be wound layer by layer in an orderly manner along the axial direction on the coil body 301.

[0073] An external display screen can also be connected to receive the output signal from the signal output unit 802 in real time, displaying the current displacement value and output voltage value, which is convenient for on-site observation and debugging.

[0074] In the above embodiments, the preset control period is 10 milliseconds, and the preset threshold is... It is 5 millivolts, and the proportional coefficient is 5. The integral coefficient is 1.2. The differential coefficient is 0.05. The value is 0.01. Those skilled in the art should understand that the above parameters can be adjusted according to actual application scenarios. For scenarios requiring higher response speeds, the control cycle can be shortened to 5 milliseconds; for scenarios requiring higher precision, the preset threshold can be adjusted. Reduced to 2 millivolts; for sensors with different ranges, the PID coefficients can be readjusted through actual testing.

[0075] In addition to using the MLX90316 series chip, the Hall sensor 502 can also use other Hall angle sensor chips with SPI interfaces to achieve the technical solution of this invention. Similarly, in addition to using the STM32F103 series microcontroller, the control unit 801 can also use other microcontrollers with PWM output and ADC input functions to achieve the technical solution of this invention.

[0076] The calibration method for the effective radius R is as follows: After the sensor is assembled, pull the steel wire rope 6 out to a known length. Record the angle change output by Hall sensor 502 ,according to The effective radius R is calculated and written into the non-volatile memory of the control unit 801. This calibration method is performed once before each sensor leaves the factory to eliminate the influence of individual differences on measurement accuracy.

[0077] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept by means of the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A high-precision draw rope sensor, characterized in that, include: The housing assembly (1) includes a main housing (102), the bottom of the main housing (102) is open, a bottom cover (101) is installed on the bottom of the main housing (102), a bearing seat (1021) is provided on the top of the main housing (102), a gap compensation assembly (4) is provided on the top of the main housing (102), the gap compensation assembly (4) includes a mounting sleeve (401), the mounting sleeve (401) is rotatably mounted on the main housing (102), the outer wall of the mounting sleeve (401) is provided with a mounting bracket (402), and a connecting shaft (403) is rotatably mounted on the mounting bracket (402). The take-up assembly (3) is disposed inside the main housing (102). The take-up assembly (3) includes a rotating part and an elastic recovery part. The outer periphery of the rotating part is used to wind the wire rope (6). The elastic recovery part is connected to the rotating part and is used to apply a rotational recovery force to the rotating part. The cable assembly (7) is disposed inside the main housing (102) and is used to correct the direction of the wire rope (6) step by step to guide the wire rope (6) to form an orderly winding on the rotating part; Transmission assembly (2), which is used to transmit the rotational motion of the rotating part to the sensing and detection assembly (5). The sensing and detection component (5) is used to convert the motion state transmitted by the transmission component (2) into an electrical signal; The control circuit assembly (8) includes a control unit (801), a signal output unit (802), and a feedback sampling unit (803). The control unit (801) is electrically connected to the signal output terminal of the sensing and detection assembly (5). The output terminal of the control unit (801) is electrically connected to the input terminal of the signal output unit (802). The signal output unit (802) is used to output an electrical signal representing the displacement. The input terminal of the feedback sampling unit (803) is electrically connected to the output terminal of the signal output unit (802). The output terminal of the feedback sampling unit (803) is electrically connected to the feedback input terminal of the control unit (801). The control unit (801) is used to dynamically adjust the output parameters of the signal output unit (802) according to the deviation between the electrical signal acquisition value collected by the feedback sampling unit (803) and the target output value, thereby forming a closed-loop calibration. The sensing and detection assembly (5) includes a magnet (501) and a Hall sensor (502). The magnet (501) is mounted on the end of the connecting shaft (403) away from the worm gear (202). A mounting plate (405) is mounted on the side of the mounting bracket (402) away from the worm gear (202). The Hall sensor (502) is mounted on the side of the mounting plate (405) close to the magnet (501). The Hall sensor (502) is electrically connected to the signal input terminal of the control unit (801). The closed-loop calibration is continuously performed by the control unit (801) according to a preset control cycle, specifically including the following steps: S1, The control unit (801) reads the angle signal currently collected by the sensing and detection component. And according to the angle signal The current displacement L is calculated based on the effective radius R of the rotating component, and then the target output value corresponding to the current displacement L is determined. ,in ; S2, the control unit (801) according to the current PWM duty cycle A PWM signal is generated and output to the signal output unit (802), which converts the PWM signal into an electrical signal. Output, where This represents the PWM duty cycle in the k-th control cycle. and Proportional, and ,in The reference voltage of the signal output unit (802) is used; the control unit (801) achieves precise control of the output voltage by adjusting the duty cycle of the PWM signal; S3, the feedback sampling unit (803) collects the electrical signal value currently actually output by the signal output unit (802). and the electrical signal acquisition value The data is transmitted back to the control unit (801); the sampling accuracy of the feedback sampling unit (803) is affected by its operating voltage. The influence of electrical signal acquisition values Compared with the actual output value The relationship between them satisfies: in The reference voltage of the feedback sampling unit (803) is The actual operating voltage of the feedback sampling unit (803); The control unit (801) monitors the actual operating voltage of the feedback sampling unit (803) in real time during the closed-loop calibration process. And by reverse-engineering the above relationship, the actual output value is obtained. In order to eliminate the acquisition error introduced by the operating voltage fluctuation of the feedback sampling unit (803); S4, the control unit (801) outputs the actual value. As a benchmark, calculate its relationship with the target output value. deviation value ,in ; S5. The control unit (801) determines whether the absolute value of the deviation value |e(k)| is greater than a preset threshold. ,like Then, based on the aforementioned deviation value The sign and magnitude of the signal determine the adjustment direction and step size, and the PWM duty cycle is updated according to the following formula: ； in This is the proportionality coefficient. The integral coefficient is... The differential coefficients are... Update the PWM duty cycle and return S2; if If the current PWM duty cycle remains unchanged, the closed-loop calibration of the current control cycle will end.

2. The high-precision draw rope sensor according to claim 1, characterized in that: The rotating part includes a spool body (301) and a drive shaft (307). One end of the wire rope (6) is wound around the spool body (301). The other end of the wire rope (6) is guided by the cable laying assembly (7) and passes through the side wall of the main housing (102) and is connected to a wire buckle (601). The spool body (301) is mounted on the drive shaft (307). A bearing (308) is sleeved on the drive shaft (307). An insert sleeve (309) is embedded inside the bearing seat (1021). The outer ring of the bearing (308) is installed inside the insert sleeve (309).

3. The high-precision draw rope sensor according to claim 2, characterized in that: The elastic recovery section includes a disc frame (302), which is located inside the main body of the coil (301). A shaft core (304) is rotatably mounted in the middle of the disc frame (302). The lower end of the transmission shaft (307) is installed inside the upper end of the shaft core (304). Disc covers (303) are installed at the top and bottom of the disc frame (302). The disc cover (303) at the bottom is fixedly connected to the bottom cover (101). Coil springs (305) are provided at the top and bottom of the disc frame (302). The inner end of the coil spring (305) is fixedly connected to the shaft core (304), and the outer end of the coil spring (305) is fixedly connected to the inner wall of the disc frame (302). A positioning shaft (306) is embedded in the upper end of the bottom cover (101). The upper end of the positioning shaft (306) is rotatably inserted into the lower end of the shaft core (304).

4. The high-precision draw rope sensor according to claim 2, characterized in that: The transmission assembly (2) includes a worm (201) and a worm wheel (202). The worm (201) is located at the upper end of the transmission shaft (307). The worm wheel (202) meshes with the worm (201) and is rotatably mounted on the clearance compensation assembly (4).

5. The high-precision draw rope sensor according to claim 4, characterized in that: The worm gear (202) is located at one end of the connecting shaft (403). The top of the main housing (102) is provided with a limiting block (1022). A torsion spring (404) is sleeved on the limiting block (1022). The lower end of the torsion spring (404) abuts against the main housing (102), and the upper end of the torsion spring (404) abuts against the lower end of the mounting bracket (402).

6. The high-precision draw rope sensor according to claim 2, characterized in that: The cable assembly (7) includes a plurality of support rods (701) arranged along the outer periphery of the main body (301) of the cable reel. The support rods (701) are mounted on the bottom cover (101). A guide sleeve (702) is rotatably sleeved on the support rods (701). The guide sleeve (702) can slide up and down along the height direction of the support rods (701). The guide sleeve (702) is provided with a guide wheel (703) for guiding the wire rope (6).

7. The high-precision draw rope sensor according to claim 1, characterized in that: The top of the main housing (102) is fitted with a cover (103), and the control circuit assembly (8), gap compensation assembly (4), transmission assembly (2) and sensing and detection assembly (5) are all located inside the cover (103).

8. The high-precision draw rope sensor according to claim 1, characterized in that: A sealing gasket (104) is provided between the bottom cover (101) and the main housing (102).

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