High-precision servo liquid level meter

Abstract

The utility model discloses a high-precision servo liquid level meter which comprises a shell, a servo motor, a measuring wheel, a measuring cable and a floater and further comprises a main encoder and an auxiliary encoder which are coaxially arranged, the main encoder is in rigid connection with an output shaft of the servo motor, and the auxiliary encoder is in transmission connection with the measuring wheel through a magnetic coupling. The signal output ends of the main encoder and the auxiliary encoder are connected with a difference compensation controller. According to the utility model, the main encoder, the auxiliary encoder and the laser-assisted positioning module are arranged, so that the measurement precision is improved; the electromagnetic compatibility is improved by arranging a three-layer composite shielding structure, and conducted interference is blocked through transmission of the magnetic coupling coupler; the spiral layer realizes temperature self-compensation; due to the combined design of the floater, the flow guide fins and the micro-grooves, the applicable medium viscosity is expanded; the transmission of the magnetic coupling coupler reduces mechanical wear, and the elastic tension adjusting mechanism automatically maintains the tension of the cable without manual maintenance; and a self-diagnosis algorithm is built in the difference compensation controller, so that the fault early warning accuracy is improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to liquid level gauge technical field especially relates to a high accuracy servo liquid level gauge. BACKGROUND

[0002] Servo liquid level gauge is generally driven by servo mechanism through soft cable winding on wheel hub to drive a liquid level sensor, such as buoyancy type or other mode liquid level sensing component, when liquid level changes, the information of liquid level sensor, such as buoyancy or capacitance or other signal changes, servo mechanism moves, wheel hub rotates, drives liquid level sensor to move up and down, reaches new signal balance point, and balances on liquid level.

[0003] The existing servo liquid level gauge adopts single encoder structure, and has the following technical defects: 1, only relying on servo motor shaft end encoder to indirectly calculate liquid level, transmission chain error (such as gear gap, cable slip) leads to cumulative error; 2, poor anti-interference: the shielding effect of traditional metal shell on high-frequency electromagnetic interference (such as frequency converter harmonic) is insufficient, leading to signal distortion; 3, weak environmental adaptability: cable thermal expansion and liquid level fluctuation affect measurement stability; 4, high maintenance cost: mechanical coupling needs to be replaced regularly, and tension adjusting mechanism relies on manual calibration. UTILITY MODEL CONTENT

[0004] The utility model discloses a high accuracy servo liquid level gauge, and researches and improves the existing structure and defects, provides a high accuracy servo liquid level gauge, to reach better practical value's purpose.

[0005] In order to realize the above-mentioned purpose, the utility model adopts the following technical scheme:

[0006] A kind of high accuracy servo liquid level gauge, including shell, servo motor, measuring wheel, measuring cable and float, it is characterized by further including coaxial main encoder and vice encoder, the main encoder is rigidly connected with the servo motor output shaft, the vice encoder is connected with the measuring wheel by magnetic coupling coupling, the signal output end of main encoder and vice encoder is connected with difference compensation controller.

[0007] In some embodiments, the measuring wheel two sides are symmetrically provided with elastic tension adjusting mechanism, the elastic tension adjusting mechanism includes adjustable support, tension detection roller and pressure sensor, the pressure sensor and the difference compensation controller form closed loop feedback.

[0008] In some embodiments, the tension detection roller surface is provided with a spiral guide groove, the guide groove depth changes along the circumference with a gradient difference of 0.05-0.2mm, and the measuring cable is embedded in the guide groove.

[0009] In some embodiments, the magnetic coupling shaft includes a permanent magnet rotor and a conductor rotor, both of which are filled with a magneto-rheological fluid in a gap, and the conductor rotor is provided with an electromagnetic coil on the outer periphery.

[0010] In some embodiments, the inner wall of the shell is provided with a three-layer shielding structure, which includes a first shielding layer, a second shielding layer and a third shielding layer from inside to outside, and each layer is connected by conductive adhesive.

[0011] In some embodiments, the measuring cable is a composite core structure, which includes a carbon fiber center wire, a spiral layer and a polytetrafluoroethylene coating layer, and the pitch of the spiral layer changes with a gradient of 0.8-1.2μm / ℃.

[0012] In some embodiments, the float bottom is further provided with a turbulence cavity, the turbulence cavity is an inverted circular truncated cone structure, a plurality of flow guide fins are evenly distributed on the inner wall of the turbulence cavity, and a plurality of V-shaped micro grooves are arrayed on the plurality of flow guide fins.

[0013] In some embodiments, a laser assisted positioning module is further included, the laser assisted positioning module includes a laser emitter arranged at the bottom of the shell and four photoelectric sensors arranged in a ring around the outlet of the measuring cable, and the laser emission axis forms an angle of 5-15° with the movement direction of the measuring cable.

[0014] The high-precision servo liquid level meter has the following advantages:

[0015] 1) The transmission chain error is eliminated by the double-encoder detection of the main encoder and the auxiliary encoder, the torque fluctuation is dynamically compensated by the magneto-rheological coupling shaft, and the laser assisted positioning module is used to correct the swing error of the measuring cable in real time, so that the measurement accuracy is improved significantly; 2) The anti-interference ability is enhanced: the electromagnetic compatibility is improved by the three-layer composite shielding structure, and the magnetic coupling shaft transmission blocks the conducted interference; 3) The environmental adaptability is optimized: the temperature self-compensation is realized by the spiral layer; the combination of the float, the flow guide fin and the micro groove expands the applicable medium viscosity; 4) The reliability and service life are improved: the non-contact magnetic coupling shaft transmission reduces mechanical wear, the elastic tension adjusting mechanism automatically maintains the cable tension, and manual maintenance is not required; the self-diagnosis algorithm in the difference compensation controller greatly improves the fault warning accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A three-dimensional structure schematic diagram of the high-precision servo liquid level meter is provided.

[0017] Figure 2 A cross-sectional view of a high-precision servo liquid level meter is provided in the utility model.

[0018] Figure 3 A cross-sectional view of a high-precision servo liquid level meter is provided in the utility model. Figure 2 A cross-sectional view of a high-precision servo liquid level meter is provided in the utility model.

[0019] Figure 4 A cross-sectional view of a high-precision servo liquid level meter is provided in the utility model.

[0020] Figure 5 A cross-sectional view of a high-precision servo liquid level meter is provided in the utility model. Figure 4 A cross-sectional view of a high-precision servo liquid level meter is provided in the utility model.

[0021] Figure 6 A cross-sectional view of a high-precision servo liquid level meter is provided in the utility model.

[0022] In the drawings: 1, the shell; 11, first shielding layer; 12, second shielding layer; 13, third shielding layer; 141, laser emitter; 142, photoelectric sensor; 101, adjustable support; 102, tension detection roller; 103, pressure sensor; 2, servo motor; 3, measuring wheel; 4, measuring cable; 401, carbon fiber center wire; 402, spiral layer; 5, float; 501, spoiler cavity; 502, guide fin; 503, V-shaped micro-groove; 6, main encoder; 7, auxiliary encoder; 8, magnetic coupling shaft coupling; 801, permanent magnet rotor; 802, conductor rotor; 803, magnetorheological fluid; 804, electromagnetic coil. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and indicated in the drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0024] With reference to Figures 1 to 6In a preferred embodiment, a high-precision servo liquid level meter comprises a housing 1, a servo motor 2, a measuring wheel 3, a measuring cable 4, and a float 5, and further comprises a primary encoder 6 and a secondary encoder 7 arranged coaxially, the primary encoder 6 is rigidly connected with the output shaft of the servo motor 2, the secondary encoder 7 is drivingly connected with the measuring wheel 3 through a magnetic coupling shaft 8, and the signal output ends of the primary encoder 6 and the secondary encoder 7 are connected with a difference compensation controller. The housing 1 is a rectangular cuboid sealing structure, the surface thereof is anodized, and the inside thereof is provided with reinforcing ribs and mounting rails. The top of the housing 1 is reserved with a servo motor 2 mounting seat, the middle thereof is provided with a bearing support of the measuring wheel 3 coaxially aligned with the servo motor shaft, the bottom thereof is provided with a measuring cable guide hole, and a polytetrafluoroethylene wear-resistant bushing is embedded in the measuring cable guide hole for the measuring cable 4 to vertically pass out; the side wall is integrated with heat dissipation fins and explosion-proof wiring terminals. The servo motor 2 is installed through a flange, is precisely matched with the top mounting seat of the housing 1 through a stop opening positioning, the output shaft of the servo motor 2 is directly connected with the main shaft of the measuring wheel 3 through a rigid coupling, and the two ends of the coupling are fixed by taper clamping sleeves. The measuring wheel 3 is a double-flange structure, the surface thereof is processed into a V-shaped groove, is located directly below the servo motor 2, the axes of the two are coincident, and the two sides of the wheel body of the measuring wheel 2 are supported in the bearing seat of the housing 1 through angular contact ball bearings. The starting end of the measuring cable 4 is fixed in the winding number of the wheel groove through a wire pressing screw ≥ 5 turns (anti-slip design), the measuring cable 4 is led out from the bottom of the measuring wheel 3, forms an S-shaped winding path through a guide roller set, reduces the radial deflection, vertically drops after passing through the guide hole at the bottom of the housing 1, and is bolted with a stainless steel clamp and a lifting ring at the top of the float 5 through a stainless steel clamp, and the measuring cable 4 is provided with an elastic tension adjusting mechanism in the internal section of the housing 1. The float 5 is a cylindrical structure, a stainless steel lifting ring is welded at the top center thereof, and the lifting ring is locked with a quick connector at the end of the measuring cable 4 through a split pin. In a static state, the float is hung directly below the housing 1; in a working state, moves along the vertical direction with the change of the liquid level, the travel range is 0-20 m, the conical structure at the bottom of the float 5 is embedded in the liquid surface, and a density adjusting layer (counterweight cavity) makes the average density of the float 1.2 times that of the measured medium. The servo motor 2, the rigid coupling, the measuring wheel 3, the measuring cable 4, and the float 5 form a closed-loop motion control. From top to bottom, they are the servo motor 2, the measuring wheel 3, the cable guide mechanism, the housing outlet, and the float 5 is independent of the housing, and realizes mechanical linkage through the measuring cable 4. The guide hole at the bottom of the housing 1 is sealed by double-layer lip-shaped sealing rings (fluorine rubber). The layout ensures the coaxial accuracy of power transmission, the vertical guidance of the measuring cable 4 reduces the horizontal swing error, the suspension design of the float 5 makes it only bear axial tension and avoids lateral force interference, and the overall structure realizes ±0.05 mm level detection while ensuring sealing.

[0025] As Figure 2As shown in some embodiments, the elastic tension adjusting mechanism is symmetrically arranged on both sides of the measuring wheel 3, and includes an adjustable support 101, a tension detection roller 102, and a pressure sensor 103, and the pressure sensor 103 forms a closed-loop feedback with the difference compensation controller. Specifically, the adjustable support 101 is an L-shaped aluminum alloy component, which is symmetrically installed on both sides of the measuring wheel 3 and is slidably connected to the shell 1 through a linear guide rail; the tension detection roller 102 is a cylindrical surface with hard oxide treatment, which is hinged to the adjustable support 101 through the elastic arm of the pressure sensor 103, and can detect the tension (20-50 N) of the measuring cable 4 in real time, and can close-loop adjust the displacement (±5 mm) of the adjustable support 101, so as to ensure that the wrapping angle of the measuring cable 4 is stably within the range of 120°-150°.

[0026] In some embodiments, the surface of the tension detection roller 102 of the elastic tension adjusting mechanism is provided with a spiral guide groove, and the depth of the guide groove changes along the circumferential direction with a gradient difference of 0.05-0.2 mm. Further, the spiral guide groove has a circumferential spiral angle of 15° along the tension detection roller 102, and the groove depth gradually changes from 0.2 mm at the starting end to 0.8 mm at the ending end, and the groove width is 1.5 mm±0.05 mm. When the measuring cable 4 is embedded in the guide groove, the depth gradient change makes the contact pressure of the measuring cable 4 uniformly distributed along the axial direction, and cooperates with the axial micro-motion (±0.3 mm) of the roller to suppress the lateral offset of the measuring cable 4 within ±0.1 mm.

[0027] As shown in some embodiments, Figure 2 and Figure 3 As shown in some embodiments, the magnetic coupling shaft coupling 8 includes a permanent magnet rotor 801 and a conductor rotor 802, and the gap between the permanent magnet rotor 801 and the conductor rotor 802 is filled with a magnetorheological fluid 803, and the conductor rotor 802 is provided with an electromagnetic coil 804 on the outer periphery. Specifically, the permanent magnet rotor 801 is a neodymium iron boron magnetic ring, which is embedded in the shaft end of the measuring wheel 3; the conductor rotor 802 is a copper disc coaxially fixed with the secondary encoder 7; the gap between the two is filled with the magnetorheological fluid 803, and the outer peripheral annular electromagnetic coil 804 has 500±5 turns. When energized, the viscosity change of the magnetorheological fluid 803 makes the transmission torque linearly adjustable within 0.5-5 N·m, so as to realize dynamic compensation of transmission error. The main encoder 6 is rigidly connected to the rear end of the output shaft of the servo motor 2 through a flange and is installed in the inner cavity of the top of the shell 1. The secondary encoder 7 is of a ring structure, which is nested on the drive shaft of the measuring wheel 3 and is strictly coaxial with the axis of the main encoder 6, and the axial distance between the two is 50 mm±0.1 mm. The secondary encoder 7 is non-contact transmission with the measuring wheel 3 through the magnetic coupling shaft coupling 8, the permanent magnet rotor 801 is embedded in the shaft end of the measuring wheel, and the conductor rotor 802 is fixed on the input shaft of the secondary encoder, and the gap between the two is 0.5-1 mm.

[0028] In some embodiments, the inner wall of the shell 1 is provided with a three-layer shielding structure, which includes a first shielding layer 11, a second shielding layer 12 and a third shielding layer 13 from inside to outside, and is adhered by conductive glue between each layer. Specifically, the first shielding layer 11 is a conductive sponge layer, which is a carbon-based composite material with a thickness of 3 mm, and is tightly attached to the inner wall of the shell 1; the second shielding layer 12 is a permalloy layer, which is a 0.1 mm thick nickel-iron foil, covering the outer side of the first shielding layer 11; the third shielding layer 13 is a nanocrystalline strip layer, which is a 0.05 mm thick Fe-Si-B amorphous strip, and the outermost layer is adhered to the shell by conductive glue. The total thickness of the three-layer structure is 3.15 mm, and the shielding effectiveness of 10 kHz-10 GHz electromagnetic interference is >120 dB, and the shell joint is overlapped with silver fiber cloth.

[0029] In some embodiments, the measuring cable 4 is a composite core structure, which includes a carbon fiber center wire 401, a spiral layer 402, and a polytetrafluoroethylene coating layer, wherein the spiral layer 402 is a nickel-titanium memory alloy spiral layer, and the gradient of the pitch changing with temperature is 0.8-1.2 μm / ℃. Specifically, the spiral layer 402 is a wire with a diameter of 0.1 mm wound (the initial value of the pitch is 2 mm), and the spiral layer 402 is tightly wound on the outer surface of the carbon fiber center wire 401 in a left-handed spiral manner (spiral angle 55°±2°); the polytetrafluoroethylene coating layer has a thickness of 0.2 mm and a surface friction coefficient <0.05. After the spiral layer 402 surface is sprayed with silane coupling agent and dried at 80℃, an active adhesive interface is formed, and the polytetrafluoroethylene particles are melted at 380℃ by an extruder to coat the outside of the spiral layer 402, and after cooling and setting, a dense protective layer with a thickness of 0.2 mm±0.03 mm is formed. When the temperature changes, the pitch of the spiral layer 402 is adaptively adjusted at a gradient of 1 μm / ℃, compensating for the thermal expansion of the cable (compensation accuracy ±0.01 mm / ℃).

[0030] As shown in Figure 5 In some embodiments, the float 5 is also provided with a spoiler cavity 501 at the bottom, which is an inverted circular table structure, and the inner wall of the spoiler cavity 501 is equally distributed with 6-8 guide fins 502, and a plurality of V-shaped micro grooves 503 are arrayed on the plurality of guide fins 502, specifically, the 6 guide fins 502 are equally distributed along the inner wall of the spoiler cavity 501 at an angle of 60°; a plurality of V-shaped micro grooves 503 cover the surface of the guide fin 502 at an angle of 30°. When the float 5 sinks, the guide fin 502 decomposes the vertical vortex into horizontal laminar flow, which improves the liquid surface fluctuation decay rate by 70%.

[0031] As shown in Figure 2 and Figure 6As shown, in some embodiments, a laser-assisted positioning module is also included, which comprises a laser emitter 141 arranged at the bottom of the housing 1 and four photoelectric sensors 142 arranged in a ring, with the laser emission axis forming a 5-15° angle with the movement direction of the measuring cable 4. Specifically, the laser emitter 141 is a semiconductor laser with a wavelength of 650 nm, which is installed in a slant hole (inclination angle of 10°±1°) at the bottom of the housing 1; the four photoelectric sensors 142 are arranged in a ring array around the outlet of the measuring cable 4, with each sensor having a field of view angle of 60°. The laser beam forms a 12° angle with the cable axis, and the cable swing error is corrected in real time by the position offset of the reflected light spot (detection sensitivity of 0.01 mm).

[0032] In some embodiments, the photoelectric sensor 142 of the laser-assisted positioning module adopts a four-quadrant avalanche photodiode, and its signal processing circuit includes an adaptive filter unit and a time-domain reflection analysis unit. Specifically, the four-quadrant avalanche photodiode 142 has a groove width of 0.05 mm; the adaptive filter unit adopts a switched-capacitor filter (with a cutoff frequency adjustable between 1 kHz and 10 MHz); the time-domain reflection analysis unit has a sampling rate of 1 GS / s, and calculates the absolute position of the liquid surface by measuring the round-trip time of the laser pulse (with a resolution of 1 ps), and realizes double verification in combination with the displacement of the cable.

[0033] In some embodiments, the difference compensation controller includes a signal acquisition module, a data processing module, and a signal output module, and the signal acquisition module is connected with the main encoder 6 and the auxiliary encoder 7 respectively. Specifically, the difference compensation controller adopts an FPGA chip to execute a sliding mode observer to establish a transfer function model of the magnetic coupling shaft coupling 8; an improved RBF neural network is set with 5 nodes in the input layer (including parameters such as temperature, tension, and phase difference), 12 nodes in the hidden layer, and 2 nodes in the output layer (compensation amount X / Y axis), with a training error of <0.001%. The algorithm outputs a correction signal every cycle (1 ms), which reduces the nonlinear error of the system by 98%. The difference compensation controller also includes a signal acquisition diagnosis unit for implementing a self-diagnosis algorithm in cooperation with software logic, a hardware state monitoring unit, and a mechanical performance evaluation unit; the signal acquisition diagnosis unit; the signal acquisition diagnosis unit is used to compare the pulse signal phase difference of the main encoder 6 and the auxiliary encoder 7 in real time, set a threshold value (±0.01°), trigger an abnormal code E01 when the threshold value is exceeded, verify the encoder data packet using a CRC-16 check algorithm, and the error rate is >1×10 -6An alarm signal is generated. The hardware state monitoring unit is used to monitor the electromagnetic coil current of the magnetic coupling shaft coupling 8. If the current fluctuation is > ± 0.1 A (for 10 ms), it is determined that the coil is short-circuited / broken, the code E02 is triggered, the working temperature of the FPGA and the DSP is collected through the DS18B20 chip (-40℃ ~ +125℃), and the over-temperature (> 85℃) starts the heat dissipation strategy (frequency reduction or shutdown). The mechanical performance evaluation unit is used to analyze the harmonic components of the servo motor 2 current, establish a bearing vibration characteristic library (frequency 1-5 kHz), and generate a replacement prompt when the 3rd harmonic amplitude rises by 20% (code E03). The cumulative bending times and tensile load of the measurement cable 4 are statistically measured, combined with the phase change times of the spiral layer 402, to generate a replacement prompt.

[0034] The dual encoders (main encoder 6 and secondary encoder 7) are non-contact synchronous monitoring through the magnetic coupling shaft coupling 8, the elastic tension mechanism maintains the constant tension of the measurement cable 4, the three-layer shielding structure and the laser-assisted positioning module jointly suppress environmental interference, the spiral layer 402 and the dynamic algorithm of the difference compensation controller cooperatively compensate for temperature deformation, and finally the ±0.05mm measurement accuracy is realized through the five-level precision guarantee system (mechanical compensation→ electromagnetic shielding→ fluid optimization→ optical calibration→ intelligent algorithm), which is more than 10 times higher than the traditional scheme.

[0035] Working principle: Before work, the laser-assisted positioning module scans the liquid surface through a 5-15° inclined laser beam, a four-quadrant avalanche photodiode receives the reflected signal, and a time-domain reflection analysis unit calculates the initial fluctuation range of the liquid surface to determine the measurement reference surface. The elastic tension adjustment mechanism detects the pre-tightening force of the measurement cable 4 through the pressure sensor 103, drives the adjustable support 101, adjusts the position of the tension detection roller 102, and combines the gradient depth change of the spiral guide groove to make the cable tension stable in the range of 20-50N. The three-layer shielding structure forms a composite electromagnetic barrier when energized, the second shielding layer 12 suppresses low-frequency magnetic field interference, and the third shielding layer 13 absorbs high-frequency noise, with a shielding effectiveness of more than 120dB. The difference compensation controller drives the main encoder 6 and the secondary encoder 7 through the magnetic coupling shaft coupling 8 to perform no-load alignment, eliminates the initial mechanical gap error based on the sliding mode observer, and ensures that the pulse phase difference of the dual encoders is ≤0.01°.

[0036] In work, the servo motor 2 drives the measuring wheel 3 to release / roll up the measuring cable 4, the main encoder 6 directly collects the motor shaft angular displacement, the auxiliary encoder 7 indirectly obtains the actual angular displacement of the measuring wheel through the magnetorheological fluid coupling 803, and the double signals are transmitted into the difference compensation controller in real time. The magnetorheological torque correction: the annular electromagnetic coil of the magnetic coupling coupling 8 adjusts the viscosity of the magnetorheological fluid 803 according to the difference between the main encoder 6 and the auxiliary encoder 7, and dynamically compensates the torque fluctuation in the range of 0.5-3 N·m. The temperature deformation offset: the helical layer 402 automatically adjusts the pitch (0.8 μm / ℃) with temperature, offsetting the length error caused by the thermal expansion of the cable. When the float 5 sinks, the spoiler cavity 501 guides the fluid through the flow guide fin 502, and the V-shaped micro groove 503 converts the turbulent flow into laminar flow, reducing the influence of liquid surface fluctuation on the attitude of the float, and the measurement fluctuation amplitude is less than or equal to ±0.1 mm. The difference compensation controller executes the dynamic error correction algorithm: an improved RBF neural network is used to predict the nonlinear error (such as cable swing and mechanical hysteresis); the liquid surface fluctuation data of the laser assisted positioning module are fused to generate a compensation signal; and finally the liquid level value with an accuracy of ±0.05 mm is output.

[0037] After work, the measuring cable 4 stress relaxation reset elastic tension adjusting mechanism automatically releases the cable tension to 5N, uses the phase change characteristics of the helical layer 402 to restore the initial shape of the cable, and avoids long-term stress deformation. The magnetic coupling coupling 8 executes the reverse current demagnetization program, eliminates the residual magnetism of the permanent magnet rotor 801, prevents the magnetorheological fluid 803 from solidifying and blocking, and prolongs the service life by more than 30%. The difference compensation controller analyzes historical data, establishes an error evolution model through an LSTM neural network, generates a device health degree evaluation report, and predicts the maintenance period of key components (such as encoders and couplings). According to the work record, automatically switch the low temperature (-50℃) / high temperature (200℃) mode: when the temperature is high, activate the third shielding layer 13 of the heat radiation enhancement coating.

[0038] The contents not described in detail in the specification all belong to the prior art known to those skilled in the art.

[0039] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto. The replacement can be a partial structure, device, method step replacement, or a complete technical solution. According to the technical scheme and the utility model concept of the present application, equivalent replacement or change should be covered within the protection scope of the present application.

Claims

1. A high-precision servo liquid level gauge comprising a housing (1), a servo motor (2), a measuring wheel (3), a measuring cable (4) and a float (5), characterized in that, Also include coaxial main encoder (6) and vice encoder (7), the main encoder (6) is rigidly connected with the servo motor (2) output shaft, the vice encoder (7) is drivenly connected with the measuring wheel (3) through the magnetic coupling coupling (8), the signal output end of the main encoder (6) and vice encoder (7) is connected with the difference compensation controller.

2. The high precision servo level gauge as claimed in claim 1, wherein, The elastic tension adjusting mechanism is symmetrically arranged on both sides of the measuring wheel (3), and comprises an adjustable support (101), a tension detection roller (102) and a pressure sensor (103).

3. The high precision servo level gauge as claimed in claim 2, wherein, The surface of the tension detection roller (102) is provided with a spiral guide groove, the depth of the guide groove changes along the circumference, the gradient difference is 0.05-0.2mm, and the measuring cable (4) is embedded in the guide groove.

4. The high precision servo level gauge as claimed in claim 1, wherein, The magnetic coupling coupling (8) comprises a permanent magnet rotor (801) and a conductor rotor (802), the permanent magnet rotor (801) and the conductor rotor (802) are filled with a magneto-rheological fluid (803) in the gap, and the conductor rotor (802) is provided with an electromagnetic coil (804) on the outer periphery.

5. The high precision servo level gauge as claimed in claim 1, wherein, The inner wall of the shell (1) is provided with a three-layer shielding structure, the three-layer shielding structure comprises a first shielding layer (11), a second shielding layer (12) and a third shielding layer (13) from inside to outside, and each layer is connected by conductive adhesive.

6. The high precision servo level gauge as claimed in claim 1, wherein, The measuring cable (4) has a composite core structure, the composite core structure comprises a carbon fiber center wire (401), a spiral layer (402) and a polytetrafluoroethylene coating layer, and the pitch of the spiral layer (402) changes by 0.8-1.2μm / ℃ with temperature.

7. The high precision servo level gauge as claimed in claim 1, wherein, The float (5) is further provided with a spoiler cavity (501) at the bottom, the spoiler cavity (501) is an inverted circular table structure, a plurality of guide fins (502) are equally distributed on the inner wall of the spoiler cavity (501), and a plurality of V-shaped microgrooves (503) are arrayed on the plurality of guide fins (502).

8. The high precision servo level gauge as claimed in claim 1, wherein, The laser auxiliary positioning module comprises a laser emitter (141) arranged at the bottom of the shell (1) and four photoelectric sensors (142) annularly distributed at the outlet periphery of the measuring cable (4), and the laser emission axis forms an angle of 5-15° with the movement direction of the measuring cable (4).

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