Apparatus and system for removing interference phenomenon in multi-component force sensor using analog circuit

Abstract

The present invention relates to an apparatus and system for eliminating interference between force components occurring in a multi-component force meter that simultaneously measures multiple force components acting on an object. More specifically, the present invention relates to an interference cancellation computing device and an interference cancellation computing system that obtain an interference-free output signal by processing the signal output from the Wheatstone bridge circuit of the multi-component force meter in real time in an analog computing circuit without quantifying it.

Description

Technology Field

[0001] The present invention relates to an apparatus and system for eliminating interference between force components occurring in a multi-component force meter that simultaneously measures multiple force components acting on an object. More specifically, the present invention relates to an interference cancellation computing device and an interference cancellation computing system that obtain an interference-free output signal by processing the signal output from the Wheatstone bridge circuit of the multi-component force meter in real time in an analog computing circuit without quantifying it. Background Technology

[0003] Multicomponent forcemeters, which simultaneously measure forces and moments acting on an object, are widely used in various industrial fields such as aerospace, shipbuilding and marine engineering, automotive, and robotics. Generally, multicomponent forcemeters can simultaneously measure six components of force, including three force components Fx, Fy, and Fz, and three moment components Mx, My, and Mz. These multicomponent forcemeters can be applied to model testing, structural load measurement, robot tactile sensing, wind tunnel testing, and water tank testing.

[0004] The sensing portion of the multi-component force meter can operate by generating deformation in a specific area in proportion to the applied component force, detecting this deformation with a strain gauge, and converting it into a voltage output in a Wheatstone bridge circuit. The Wheatstone bridge circuit consists of four resistors and can output a measurement signal by converting the resistance change of the strain gauge into a voltage change. The output signal can be transmitted to a data logger or signal processing device for recording and analysis.

[0005] In the design of a multi-component force meter, the structural shape of the sensing element must be designed so that deformation in a specific area occurs solely due to the influence of the force component to be measured and is unaffected by other forces. However, there may be cases where it is difficult to design a completely independent sensing structure due to constraints such as measurement capacity, installation space, and material properties. In such cases, the influence of forces other than the one intended for measurement may be included in the output signal, a phenomenon known as interference between forces.

[0006] Interference phenomena in multi-component force meters can occur depending on design, manufacturing, assembly, and installation conditions. During the design phase, the geometric shape of the sensing element, the placement of strain gauges, and the configuration method of the bridge circuit can affect interference. During the manufacturing phase, machining tolerances, surface roughness, and residual stress can affect interference. During the assembly and installation phases, tightening torque, alignment errors, and contact conditions can affect interference.

[0007] The interference characteristics of the force component can be quantified through calibration testing. In calibration testing, the interference coefficient can be calculated by independently applying a reference load to each force component and measuring the output of all channels. The interference coefficient can be expressed in a matrix form based on the combination of the measured load direction and the applied load, which can be referred to as the interference matrix or calibration matrix. The sensitivity, zero point, nonlinearity, hysteresis, and interference coefficient of each channel may be recorded in the calibration test report.

[0008] The relationship between the force components and the output signal can be expressed as a system of linear equations. In this system, the output signal can be represented as a linear combination of the force component to be measured and the interference coefficient. By solving the system of equations, the pure force component can be separated from the output signal containing interference. This mathematical separation process can be performed by applying numerical analysis techniques such as matrix inversion or the least squares method.

[0009] For models with a large ratio of diameter to length, such as slender underwater vehicles, submarine models, and torpedo models, it may be difficult to install large force meters due to limited internal space. Force meters installed in such confined spaces may have characteristics that make it difficult to physically eliminate interference due to structural constraints. For force meters for slender models, a column element structure subjected to eccentric loading may be applied, and this structure may have the characteristic of simultaneously detecting bending and compression signals.

[0010] In a water tank test environment, multi-component meters may be exposed to various environmental factors, such as changes in water temperature, water pressure, vibrations caused by flow, and electromagnetic noise. Changes in water temperature can cause changes in the resistance values ​​of strain gauges and bridge circuits, which may lead to variations in the zero point and sensitivity of the output signal. Vibrations caused by flow can apply mechanical stress to the component meter structure and connecting cables and generate microphonic noise. Electromagnetic noise generated from equipment such as towing motors, wave generators, and inverters can cause interference with the measurement signal.

[0011] Analog and digital signal processing methods can be applied to the output signal processing of a multi-component system. In analog signal processing, signal amplification, filtering, and computation can be performed using analog components such as operational amplifiers, resistors, and capacitors. In digital signal processing, the output signal is digitized through an analog-to-digital converter, and numerical computations can be performed by a microprocessor or a digital signal processor.

[0012] Operational amplifiers are core components of analog signal processing and can possess high open-loop gain, high input impedance, and low output impedance. Using operational amplifiers, various analog operation circuits such as inverting amplifiers, non-inverting amplifiers, adders, subtractors, integrators, and differentiators can be constructed. Adder circuits can perform the function of summing multiple input signals and can be classified into inverting adders and non-inverting adders.

[0013] Resistors can perform functions such as current limiting, voltage division, and gain setting in analog circuits. Types of resistors include carbon film resistors, metal film resistors, wire-wound resistors, and thin-film resistors. Thin-film resistors can be manufactured by forming a thin film of a metal or metal compound on a ceramic substrate and can possess high precision and a low temperature coefficient. Tantalum nitride thin-film resistors can exhibit excellent chemical stability and long-term stability.

[0014] A resistance thermometer can be a sensor that measures temperature by utilizing the change in resistance value according to temperature. Platinum resistance thermometers can be widely used for precise temperature measurement because the change in resistance value according to temperature is linear and highly reproducible. Pt100 may be a specification for a platinum resistance thermometer with a resistance value of 100 ohms at 0°C. A voltage output corresponding to the temperature change can be obtained by connecting the resistance thermometer to a Wheatstone bridge circuit.

[0015] Magnetic shielding can be a technology that protects electronic circuits from external magnetic fields. Silicon steel sheets, permalloy, mumetal, and nanocrystalline soft magnetic alloys can be used as magnetic shielding materials. Nanocrystalline soft magnetic alloys are materials formed by heat-treating amorphous alloys to create nanometer-sized grains, and they can possess high initial permeability and low coercivity. Fe-Si-B-Nb-Cu-based nanocrystalline soft magnetic alloys may be materials known as Finemet.

[0016] Supercapacitors are devices that store energy using an electric double layer or pseudo-capacitance, and can have a higher capacitance than ordinary capacitors. Aqueous electrolytes, organic electrolytes, and ionic liquids can be used as electrolytes for supercapacitors. Ionic liquids are salts that are in a liquid state at room temperature and can exhibit stable characteristics over a wide temperature range. A combination of imidazolium-based cations and bistrifluoromethanesulfonylimide anions can provide high ionic conductivity and electrochemical stability.

[0017] Piezoelectric materials can possess the property of converting mechanical stress into electrical signals or electrical signals into mechanical displacement. PZT-based materials are widely used as piezoelectric ceramics. Piezoelectric single crystals can exhibit higher piezoelectric properties than polycrystalline piezoelectric ceramics, and relaxed ferroelectric single crystals such as PMN-PT and PZN-PT are representative examples. PMN-PT single crystals possess high piezoelectric constants and electromechanical coupling coefficients, making them suitable for application in precision actuators and sensors.

[0018] MEMS technology can be a technology that integrates micrometer-sized mechanical structures and electronic circuits using semiconductor processes. MEMS accelerometers can measure acceleration by detecting the displacement of an inertial mass through changes in capacitance or the piezoelectric effect. MEMS accelerometers can be characterized by their small size, low power consumption, and low cost, and can be applied to vibration monitoring, shock detection, attitude control, and the like. The problem to be solved

[0020] In one aspect of the present invention, an interference cancellation computing device is provided that can continuously acquire an interference-free output signal by eliminating interference between force components of a multi-force system in real time.

[0021] In one aspect of the present invention, an interference cancellation operation device capable of maintaining signal continuity by performing an interference cancellation operation in an analog signal state without quantifying the output signal.

[0022] In one aspect of the present invention, an interference cancellation computing device is provided that can be installed between the output terminal of an existing force meter and a data processing device to improve measurement precision while maintaining the existing measurement plan.

[0023] In one aspect of the present invention, an interference cancellation computing device capable of responding to various environmental factors such as temperature changes, electromagnetic noise, and mechanical vibration in a water tank test environment is provided.

[0024] In one aspect of the present invention, the invention aims to provide an interference cancellation computing device capable of maintaining stable interference cancellation performance even during long-term underwater operation.

[0025] In one aspect of the present invention, an interference cancellation computation system is provided that is composed of a plurality of modules and performs respective computational functions. means of solving the problem

[0027] According to one aspect of the present invention, an interference removal operation device for removing interference between force components of a multi-force system that simultaneously measures a plurality of force components acting on an object is provided, comprising: an input unit connected to a Wheatstone bridge circuit of the multi-force system and receiving an output signal; a multiplication operation element connected to the input unit and including a resistance network and outputting an interference correction signal from the output signal; a summation operation element connected to the input unit and the multiplication operation element and including an adder circuit and outputting an interference removal signal from the output signal and the interference correction signal; and an amplification operation element connected to the summation operation element and including a voltage amplifier and outputting an interference separation output signal from the interference removal signal, wherein the multiplication operation element, the summation operation element, and the amplification operation element constitute an interference removal operation circuit.

[0028] For example, an interference cancellation operation device may be provided in which the resistance network of the multiplication operation element includes a variable resistor or a fixed resistor whose resistance value is set according to a calibration test result.

[0029] For example, an interference cancellation arithmetic device may be provided in which the adder circuit of the summing arithmetic element comprises an operational amplifier, an input resistor and a feedback resistor connected to the operational amplifier, and the adder circuit is an inverting adder or a non-inverting adder.

[0030] For example, an interference cancellation operation device may be provided in which the voltage amplifier of the amplification operation element comprises an operation amplifier and a gain setting resistor connected to the operation amplifier.

[0031] For example, an interference removal calculation device may be provided, wherein the interference removal calculation device comprises a first interference removal calculation circuit and a second interference removal calculation circuit connected to the output of the first interference removal calculation circuit.

[0032] For example, an interference cancellation computing device may be provided, wherein the interference cancellation computing device is disposed in the internal space of the multi-component force meter or is disposed between the output terminal of the multi-component force meter and a data logger.

[0033] For example, an interference cancellation operation device may be provided, wherein the multiplication operation element further includes a temperature compensation circuit, and the temperature compensation circuit includes a temperature detection unit including a thermistor and an analog multiplier connected to the temperature detection unit.

[0034] For example, an interference cancellation computing device may be provided in which the thermoresistor is a platinum thermoresistor and the temperature detection unit includes a bridge circuit comprising the platinum thermoresistor.

[0035] For example, an interference cancellation arithmetic device may be provided in which the platinum thermistor is Pt100 and the analog multiplier is a 4th quadrant analog multiplier.

[0036] For example, an interference cancellation operation device may be provided, which further includes a non-linear correction circuit at the rear end of the summing operation element.

[0037] For example, an interference cancellation computing device may be provided, wherein the above-mentioned nonlinear correction circuit includes a diode function generator composed of a plurality of diodes and a plurality of resistors.

[0038] For example, an interference cancellation computing device may be provided, wherein the diode function generator comprises 4 to 12 diodes and a resistor connected in series to each diode.

[0039] For example, an interference cancellation operation device may be provided, which further includes a drift compensation circuit at the output of the amplification operation element.

[0040] For example, an interference cancellation computing device may be provided in which the drift compensation circuit includes a chopper stabilization amplifier or an auto-zero amplifier.

[0041] For example, an interference cancellation computing device may be provided in which the resistance network of the multiplication computing element comprises a ceramic substrate and a tantalum nitride thin film resistor formed on the ceramic substrate.

[0042] For example, an interference cancellation computing device may be provided in which the ceramic substrate is an alumina substrate and the tantalum nitride thin film resistor is formed by reactive magnetron sputtering.

[0043] For example, an interference cancellation computing device may be provided in which the tantalum nitride thin film resistor has a thickness in the range of 80 nm to 200 nm, a sheet resistance in the range of 100 ohms / sq to 800 ohms / sq, and a temperature coefficient of ±25 ppm / ℃ or less.

[0044] For example, an interference cancellation computing device may be provided, which further includes a protective layer formed on the surface of the tantalum nitride thin film resistor.

[0045] For example, an interference cancellation computing device may be provided, wherein the protective layer is an yttria layer and the yttria layer has a thickness in the range of 10 nm to 50 nm.

[0046] For example, an interference cancellation computing device may be provided in which the resistance of the tantalum nitride thin film resistance is adjusted by laser trimming, and the laser trimming is performed by an Nd:YAG laser.

[0047] For example, an interference cancellation computing device may be provided, which further includes a magnetic shielding housing that accommodates the interference cancellation computing circuit.

[0048] For example, an interference cancellation computing device may be provided in which the magnetic shielding housing is formed of a nanocrystalline soft magnetic alloy.

[0049] For example, an interference cancellation computing device may be provided in which the nanocrystalline soft magnetic alloy is an Fe-Si-B-Nb-Cu-based alloy and the nanocrystalline soft magnetic alloy is formed by a stack of amorphous ribbons and heat treatment.

[0050] For example, an interference cancellation computing device may be provided in which the nanocrystalline soft magnetic alloy has an average grain size in the range of 5 nm to 25 nm and an initial permeability of 50,000 or more.

[0051] For example, an interference cancellation computing device may be provided in which the drift compensation circuit further includes a high-pass filter, and the high-pass filter includes a supercapacitor.

[0052] For example, an interference cancellation computing device may be provided in which the supercapacitor comprises an ionic liquid electrolyte.

[0053] For example, an interference cancellation computing device may be provided in which the ionic liquid electrolyte comprises an imidazolium-based cation and a bistrifluoromethanesulfonylimide anion.

[0054] For example, an interference cancellation computing device may be provided in which the ionic liquid electrolyte is 1-ethyl-3-methylimidazolium bistrifluoromethanesulfonylimide.

[0055] For example, an interference cancellation computing device may be provided, wherein the supercapacitor comprises an electrode composed of a composite of activated carbon and a carbon-based conductive material, and the time constant of the high-pass filter is in the range of 100 seconds to 1,000 seconds.

[0056] For example, an interference cancellation computing device may be provided, further comprising a substrate on which the interference cancellation computing circuit is mounted and an active vibration cancellation unit laminated on the substrate.

[0057] For example, an interference cancellation computing device may be provided, wherein the active vibration cancellation unit comprises an acceleration sensor attached to the substrate, a piezoelectric actuator stacked on the substrate, and a feedback control circuit connected to the acceleration sensor and the piezoelectric actuator.

[0058] For example, an interference cancellation computing device may be provided, wherein the above acceleration sensor is a MEMS acceleration sensor.

[0059] For example, an interference cancellation computing device may be provided, wherein the piezoelectric actuator comprises a piezoelectric single crystal.

[0060] For example, the piezoelectric single crystal is a lead magnesium niobate-lead titanate single crystal, and the piezoelectric single crystal has a piezoelectric constant d 33 An interference cancellation computing device having a value of 1,500 pC / N or higher may be provided.

[0061] For example, an interference cancellation computing device may be provided, wherein the feedback control circuit includes an analog PID controller and further includes a high-voltage amplifier connected to the feedback control circuit.

[0062] According to one aspect of the present invention, an interference cancellation operation system for removing interference between force components of a multi-force system that simultaneously measures a plurality of force components acting on an object may be provided, comprising: a signal input module that receives an output signal from a Wheatstone bridge circuit of the multi-force system; a multiplication operation module connected to the signal input module and generating an interference correction signal by applying an interference coefficient to the output signal; a summation operation module connected to the signal input module and the multiplication operation module and generating an interference cancellation signal by summing the output signal and the interference correction signal; and an amplification operation module connected to the summation operation module and generating an interference separation output signal by amplifying the interference cancellation signal.

[0063] For example, an interference cancellation operation system may be provided in which the multiplication operation module comprises a resistance network including a variable resistor or a fixed resistor and a buffer amplifier connected to the resistance network.

[0064] For example, an interference cancellation operation system may be provided, wherein the temperature compensation module further includes a temperature compensation module connected to the multiplication operation module, and the temperature compensation module includes a thermistor and an analog multiplier connected to the thermistor.

[0065] For example, an interference cancellation operation system may be provided, which further includes a non-linear correction module connected to the rear end of the summation operation module, wherein the non-linear correction module includes a diode function generator.

[0066] For example, an interference cancellation operation system may be provided, which further includes a drift compensation module connected to the downstream end of the amplification operation module, wherein the drift compensation module includes a chopper stabilization amplifier or an auto-zero amplifier.

[0067] For example, an interference cancellation computing system may be provided in which the resistance network comprises a tantalum nitride thin film resistor formed on a ceramic substrate.

[0068] For example, an interference cancellation operation system may be provided, further comprising a magnetic shielding housing that accommodates the multiplication operation module, the summation operation module, and the amplification operation module, wherein the magnetic shielding housing is formed of a nanocrystalline soft magnetic alloy.

[0069] For example, an interference cancellation computation system may be provided in which the drift compensation module further comprises a supercapacitor containing an ionic liquid electrolyte and a high-pass filter containing the supercapacitor.

[0070] For example, an interference cancellation operation system may be provided, further comprising a substrate on which the multiplication operation module, the summation operation module, and the amplification operation module are mounted, and an active vibration cancellation unit laminated on the substrate, wherein the active vibration cancellation unit comprises an acceleration sensor, a piezoelectric actuator comprising a piezoelectric single crystal, and a feedback control circuit comprising an analog PID controller. Effects of the invention

[0072] An interference removal computing device according to one aspect of the present invention can continuously obtain an interference-free output signal by removing interference phenomena between the components of a multi-component force system in real time.

[0073] An interference cancellation calculation device according to one aspect of the present invention performs interference cancellation calculations in an analog signal state without quantifying the output signal, so the continuity of the signal can be maintained and it can be applied to the measurement of dynamic phenomena.

[0074] An interference cancellation calculation device according to one aspect of the present invention can be installed between the output terminal of an existing force meter and a data processing device, thereby improving measurement precision while maintaining the existing measurement plan.

[0075] An interference cancellation computing device according to one aspect of the present invention may include a temperature compensation circuit, a non-linear correction circuit, a drift compensation circuit, etc., and can respond to various environmental factors in a water tank test environment.

[0076] An interference cancellation computing device according to one aspect of the present invention may include a tantalum nitride thin film resistor, an yttria protective layer, etc., so that stable interference cancellation performance can be maintained even during long-term underwater operation.

[0077] An interference cancellation computing device according to one aspect of the present invention may include a nanocrystalline soft magnetic alloy magnetic shielding housing, thereby improving the signal-to-noise ratio even in an electromagnetic noise environment.

[0078] An interference cancellation computing device according to one aspect of the present invention may include a piezoelectric single crystal active vibration cancellation unit, thereby suppressing microphonic noise under flow conditions.

[0079] An interference cancellation operation system according to one aspect of the present invention may include a signal input module, a multiplication operation module, a summation operation module, and an amplification operation module, so that each operation function can be systematically performed. Brief explanation of the drawing

[0081] FIG. 1 is a diagram showing the connection configuration of a multi-component force sensor and a data logger according to one embodiment of the present invention. FIG. 2 is a diagram showing the signal processing flow of an interference removal computing device according to one embodiment of the present invention. Specific details for implementing the invention

[0082] Hereinafter, preferred embodiments of the present invention will be described with reference to the attached drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0083] In one aspect of the present invention, the interference cancellation calculation device 200 may be for eliminating interference between force components occurring in a multi-component force meter that simultaneously measures a plurality of force components acting on an object. As illustrated in FIG. 1, the multi-component force meter can simultaneously measure six force components, including force components Fx, Fy, and Fz and moment components Mx, My, and Mz. Depending on the design, manufacturing, assembly, and installation conditions of the force meter, interference between force components may inevitably occur, and standard force meters may allow interference in the range of 3% to 7%. The interference cancellation calculation device 200 may be applied when such interference exceeds the allowable range, and may be applied to force meters where the interference is in the range of 20% to 40%, or in the range of 25% to 35%, or about 30% or less.

[0084] FIG. 1 may show the connection configuration of a multi-component force sensor and a data logger. Referring to FIG. 1, the multi-component force sensor can output six component force signals including force components Fx, Fy, and Fz and moment components Mx, My, and Mz. Each component force signal can be transmitted to the data logger through individual signal lines. Fx, Fy, and Fz can represent force components in the x-axis, y-axis, and z-axis directions, respectively, and Mx, My, and Mz can represent moment components centered on the x-axis, y-axis, and z-axis, respectively.

[0085] In one embodiment, the interference cancellation operation device 200 may include an input unit, a multiplication operation element 2, a summation operation element 3, and an amplification operation element 4. The input unit may be connected to a Wheatstone bridge circuit of a multi-component force meter to receive an output signal 1. The Wheatstone bridge circuit may detect the deformation of a specific part generated in proportion to the component force acting by the sensing unit of the force meter using a strain gauge and convert it into a voltage output. The output signal 1 may include an interference signal component caused by another component force along with a signal component corresponding to the component force to be measured.

[0086] In one embodiment, the multiplication element 2 is connected to an input section and may include a resistance network. The multiplication element 2 may output an interference correction signal multiplied by an interference coefficient obtained from a calibration test when the output signal 1 passes through the resistance network. Using the calibration constants obtained from the calibration test of the force component, the relationship between the force component and the output can be expressed as a linear system of nondimensionalized equations as shown in Equation 1. The multiplication element 2 is the interference coefficient C of Equation 1. ij A resistance network can be configured to have a distribution ratio corresponding to it.

[0087] [Mathematical Formula 1]

[0088]

[0089] Equation 1 may be a dimensionless system of linear equations representing the relationship between component force and output using calibration constants obtained from the calibration test of the component force meter. In Equation 1, S n1 To S n6 Each can represent a normalized output signal, and F1 through F6 can represent each component. Subscripts 1, 2, and 3 can represent Fx, Fy, and Fz, and subscripts 4, 5, and 6 can represent Mx, My, and Mz. Interference coefficient C ij In this, the first subscript i indicates the direction of the measured load, and the second subscript j can indicate the applied load. S ni is the output signal appearing in the sensor due to the i-direction load, and the output signal a at the maximum load. ii It can be a dimensionless signal.

[0090] FIG. 2 may show the signal processing flow of an interference cancellation operation device 200. Referring to FIG. 2, the sensor signal on the left may include six component signals Fx, Fy, Fz, Mx, My, and Mz. The sensor signal may pass through a Signal multiplying processor corresponding to multiplication operation element 2, then through a Summing processor corresponding to summing operation element 3, and then through a Signal amplifying processor corresponding to amplification operation element 4. The interference separation output signal 5 on the right may include six component signals Fx, Fy, Fz, Mx, My, and Mz from which interference has been removed.

[0091] In one embodiment, the summing operation element 3 is connected to an input unit and a multiplication operation element 2 and may include an adder circuit. The summing operation element 3 can output an interference removal signal by summing the output signal 1 and the interference correction signal output from the multiplication operation element 2. As shown in FIG. 2, the summing operation element 3 is placed after the multiplication operation element 2 to generate a signal in which the interference component is canceled out. As shown in Equation 2, when only the interference between specific components exceeds the allowable range, an interference removal signal can be obtained by subtracting the interference correction signal corresponding to the interference component from the original signal.

[0092] [Equation 2]

[0093]

[0094] Equation 2 may be a simplified relationship applied when only the interference between specific component forces exceeds the allowable range. Referring to Equation 2, F1 is 1 / a 11 x can be expressed as S1, and F2 is C 24 and C 42 It can be expressed in a way that includes the relationship of, and F4 is similarly C 24 and C 42 It can be expressed as an equation including the relationship. F3, F5, and F6 can each be expressed as simple proportional relationships. Equation 2 is, for example, the interference coefficient C between F2 and F4. 24 and C 42 If only the allowable range is exceeded, the remaining interference terms may be ignored and applied.

[0095] In one embodiment, the amplification operation element 4 is connected to the summing operation element 3 and may include a voltage amplifier. The amplification operation element 4 can amplify an interference removal signal to output an interference separation output signal 5. As shown in FIG. 2, the amplification operation element 4 may be placed after the summing operation element 3. The amplification operation element 4 can compensate for signal attenuation occurring during the operation process in the multiplication operation element 2 and the summing operation element 3, and can compensate for voltage drop in the circuit to output an interference separation output signal 5 at a rated output level.

[0096] In one embodiment, the multiplication operation element 2, the summing operation element 3, and the amplification operation element 4 can form an interference cancellation operation circuit 6. The interference cancellation operation circuit 6 can perform operations in an analog signal state without digitizing the output signal 1. Accordingly, unlike the conventional method of digitizing the output signal in a data logger and performing operations using simultaneous equations, the continuity of the signal can be maintained and it can be applied to the measurement of dynamic phenomena.

[0097] For example, before the interference cancellation computing device 200 is applied, interference caused by the My component in the Fx channel may be in the range of 20% to 30% or about 25%, interference caused by the Mz component in the Fy channel may be in the range of 8% to 15% or about 10.8%, interference caused by the My component in the Fz channel may be in the range of 12% to 22% or about 17%, and interference caused by the Mx component may be in the range of 4% to 10% or about 6.1%. After the interference cancellation computing device 200 is applied, interference in the Fx channel may be reduced to the range of 1% to 4% or about 2.4%, and interference in the Fy channel may be reduced to the range of 0.3% to 1.5% or about 0.6%. Accordingly, interference in all channels can be controlled to a range of 3% to 5% or less, which is a normal allowable range.

[0098] In one aspect of the present invention, the resistance network of the multiplication operation element 2 may include a variable resistor or a fixed resistor whose resistance value is set according to a calibration test result. The resistance network may output an interference correction signal with a distribution ratio corresponding to the interference coefficient when the output signal 1 passes through.

[0099] In one embodiment, the variable resistor may be a precision potentiometer, and the resistance value can be adjusted on-site according to the results of a calibration test. By adjusting the distribution ratio of the variable resistor, the interference coefficient C shown in Equation 1 ij A multiplication operation corresponding to this can be performed. The fixed resistor can be selected with a resistance value that exactly corresponds to the interference coefficient determined in the calibration test.

[0100] For example, the variable resistor may be a 10-turn precision potentiometer, and the resistance value range may be 100 ohms to 100 kilohms, or 1 kilohm to 50 kilohms, or 10 kilohms. The resistance value precision may be ±0.1% or less, or ±0.05% or less. The fixed resistor may be a thin-film resistor or a metal film resistor, and the temperature coefficient may be ±50 ppm / ℃ or less, or ±25 ppm / ℃ or less.

[0101] In one aspect of the present invention, the adder circuit of the summing operation element 3 may include an operational amplifier and an input resistor and a feedback resistor connected to the operational amplifier. The adder circuit may be an inverting adder or a non-inverting adder.

[0102] In one embodiment, the inverting adder may be configured such that a plurality of input resistors are connected to the inverting input terminal of the operational amplifier and a feedback resistor is connected between the output terminal and the inverting input terminal. The non-inverting adder may be configured such that an input signal is applied to the non-inverting input terminal of the operational amplifier. The summing operation element 3 may use an inverting adder to subtract an interference correction signal from the output signal 1.

[0103] For example, the operational amplifier may be a general-purpose operational amplifier, and the gain bandwidth may be 1 MHz or more, or 5 MHz or more, or 10 MHz or more. The input resistance and feedback resistance may be in the range of 1 kilohm to 1 megahm, or in the range of 10 kilohm to 100 kilohms. The resistance precision may be ±0.1% or less.

[0104] In one aspect of the present invention, the voltage amplifier of the amplification operation element 4 may include an operation amplifier and a gain setting resistor connected to the operation amplifier. The voltage amplifier can compensate for signal attenuation and voltage drop in the interference cancellation operation circuit 6.

[0105] In one embodiment, the gain setting resistor can set the gain as the ratio of the input resistor to the feedback resistor in the non-inverting amplifier configuration of the operational amplifier. The amplifying operational element 4 can be operated in conjunction with the power supply voltage regulation function of the Wheatstone bridge circuit. The amplifying operational element 4 can be operated in conjunction with the signal amplification function of the data logger.

[0106] For example, the gain of the voltage amplifier may be in the range of 1 to 100 times, or in the range of 2 to 50 times, or in the range of 5 to 20 times. The operational amplifier may be a low-noise operational amplifier, and the input offset voltage may be 1 mV or less, or 100 microvolts or less, or 10 microvolts or less.

[0107] In one aspect of the present invention, an interference cancellation calculation device 200 may include a first interference cancellation calculation circuit and a second interference cancellation calculation circuit connected to the output of the first interference cancellation calculation circuit. This configuration may be applied when interference occurs from two or more component parts.

[0108] In one embodiment, the first interference cancellation calculation circuit can preferentially separate interference components with a large absolute value of the interference coefficient. The second interference cancellation calculation circuit can receive the output of the first interference cancellation calculation circuit and separate interference components of the next rank. When there are two or more load components causing interference in an output signal detecting a specific load, the larger interference is first separated and removed, and a new calibration test is performed, thereby obtaining a new calibration test report.

[0109] For example, when isolating the largest interference, interference caused by other load components may change; therefore, while the large interference has been eliminated in the new calibration test report, the interference coefficient of the next magnitude may change. Based on the new calibration test report, a new dimensionless relationship in the form of Equation 1 can be obtained, and a second interference cancellation calculation circuit can be configured accordingly. When there is interference exceeding the allowable range, the interference can be isolated by sequentially performing the calibration test again and applying the same method. The interference eliminated by the first interference cancellation calculation circuit may be in the range of 15% to 30%, and the interference eliminated by the second interference cancellation calculation circuit may be in the range of 5% to 15%.

[0110] In one aspect of the present invention, the interference cancellation computing device 200 may be placed in the internal space of the multi-component force meter or between the output terminal of the multi-component force meter and the data logger.

[0111] In one embodiment, the entire interference cancellation calculation circuit 6 can be minimized by designing it as a single circuit so that it can be placed within the internal space of the force component. A separate auxiliary processing unit can be configured to adjust the calculation function according to the interference constant by installing it between the output terminal of the force component and the data processing device. Accordingly, interference between specific force components of the existing force component can be selectively separated to increase the precision of the force component.

[0112] For example, when placed inside the force component, the external dimensions of the interference cancellation calculation circuit 6 may be in the range of a diameter of 100 mm to 200 mm or a diameter of 150 mm to 180 mm, and in the range of a length of 300 mm to 500 mm or a length of 350 mm to 450 mm. When placed externally, the interference cancellation calculation device 200 may be housed in a separate housing and connected by a cable between the force component and the data logger. In the case of a slender underwater vehicle model, the installation space may be in the range of a diameter of 150 mm to 200 mm and a length of 350 mm to 450 mm, and the interference cancellation calculation circuit 6 may be placed within this space.

[0113] In one aspect of the present invention, the multiplication operation element 2 may further include a temperature compensation circuit. The temperature compensation circuit may include a temperature detection unit including a thermistor and an analog multiplier connected to the temperature detection unit.

[0114] In one embodiment, the temperature compensation circuit can compensate in real time for changes in the characteristics of the resistance network due to temperature changes occurring in a water bath test environment. The temperature detection unit can detect the ambient temperature and output a voltage signal corresponding to the temperature. The analog multiplier can receive the output of the temperature detection unit and the output signal 1 and output a signal to which a temperature-dependent correction coefficient is applied.

[0115] For example, if a temperature compensation circuit is not applied, the variation in the interference coefficient due to changes in water temperature may be in the range of ±2% to ±4%, or about ±2.5%. If a temperature compensation circuit is applied, the variation in the interference coefficient may be reduced to the range of ±0.3% to ±1%, or about ±0.5% or less. The water tank temperature range may be in the range of 0℃ to 40℃, or in the range of 5℃ to 30℃.

[0116] In one aspect of the present invention, the thermistor may be a platinum thermistor. The temperature detection unit may include a bridge circuit comprising the platinum thermistor.

[0117] In one embodiment, the platinum resistance thermometer may exhibit a linear and highly reproducible change in resistance value with respect to temperature. The bridge circuit may be in the form of a Wheatstone bridge composed of a platinum resistance thermometer and a reference resistor. The bridge circuit can convert the change in resistance value of the platinum resistance thermometer with respect to temperature change into a voltage output.

[0118] For example, the temperature coefficient of the platinum resistance thermometer may be in the range of +3,800 ppm / ℃ to +3,950 ppm / ℃, or about +3,850 ppm / ℃. The output voltage range of the bridge circuit may be in the range of 0 mV to 100 mV, or in the range of 0 mV to 50 mV, and may correspond to a water temperature range of 5℃ to 30℃.

[0119] In one aspect of the present invention, the platinum thermistor may be Pt100. The analog multiplier may be a 4th quadrant analog multiplier.

[0120] In one embodiment, Pt100 may be a platinum thermistor having a resistance of 100 ohms at 0°C. The 4th quadrant analog multiplier can perform multiplication operations regardless of the signs of the two input signals. In the 4th quadrant analog multiplier, an output signal 1 may be applied to the X input, and the output voltage of the temperature detector may be applied to the Y input.

[0121] For example, the resistance value of Pt100 at 0°C may be 100 ohms, the resistance value at 5°C may be in the range of 101 to 103 ohms or about 101.95 ohms, and the resistance value at 30°C may be in the range of 110 to 113 ohms or about 111.67 ohms. The bandwidth of the 4th quadrant analog multiplier may be 500 kHz or more, or 1 MHz or more. The range of the correction factor corresponding to temperature may be in the range of 0.97 to 1.03, or in the range of 0.98 to 1.02.

[0122] In one aspect of the present invention, a nonlinear correction circuit may be further included after the summing operation element 3. The nonlinear correction circuit can correct nonlinear interference components remaining after first-order interference removal based on linear systems of equations.

[0123] In one embodiment, the nonlinear correction circuit may be placed between the summing operation element 3 and the amplification operation element 4. The nonlinear correction circuit can remove higher-order interference components of order 2 or higher. The nonlinear correction circuit can correct nonlinear interference characteristics that appear in the large deformation region.

[0124] For example, nonlinear interference may occur in the range of 15% to 25% relative to the rated output of the measurement range, or at about 20% or more. Before applying the nonlinear correction circuit, the nonlinear interference may be in the range of ±2% to ±5%, or about ±3%, and after applying the nonlinear correction circuit, the nonlinear interference may be reduced to the range of ±0.5% to ±1.5%, or about ±1% or less.

[0125] In one aspect of the present invention, the nonlinear correction circuit may include a diode function generator composed of a plurality of diodes and a plurality of resistors.

[0126] In one embodiment, the diode function generator can generate an output voltage by applying a non-linear function to the input voltage. The diode function generator can implement a parabolic function or a cubic function using a segment-by-segment linear approximation method. The diode can conduct above a specific voltage by utilizing its forward voltage drop characteristics.

[0127] For example, the input voltage V of a diode function generator i Output voltage V for o is V o = V i + kx V i 2 A second-order correction can be performed in the form of. The correction factor k can be adjusted by a trimmer resistor in the range of -0.1 to +0.1 or in the range of -0.05 to +0.05.

[0128] In one aspect of the present invention, the diode function generator may include 4 to 12 diodes and a resistor connected in series to each diode.

[0129] In one embodiment, a plurality of diodes may be combined with a resistor to each have a different breakpoint voltage. Each combination of diode and resistor may cause a change in slope in a specific input voltage range. The approximation precision may be determined by the number of diodes.

[0130] For example, the number of diodes may be in the range of 4 to 8, or in the range of 6 to 10, or 8. The diode breakpoint voltage interval may be in the range of 0.3V to 1V, or in the range of 0.4V to 0.7V, or about 0.5V. The diodes may be precision diodes or small-signal diodes, and the forward voltage drop may be in the range of 0.5V to 0.8V, or in the range of about 0.6V to 0.7V. The total number of approximate intervals may be in the range of 6 to 12, or in the range of 8 to 10.

[0131] In one aspect of the present invention, a drift compensation circuit may be further included after the amplification operation element 4. The drift compensation circuit can eliminate DC offset and low-frequency drift components that occur during long-term measurement.

[0132] In one embodiment, the drift compensation circuit may be placed between the amplification operation element 4 and the interference separation output signal 5. The drift compensation circuit can compensate for the DC offset accumulated during a long-term water bath test of several hours to tens of hours. The drift compensation circuit can detect and cancel out low-frequency drift components.

[0133] For example, before applying the drift compensation circuit, the zero drift may be in the range of 0.3% / hour to 0.8% / hour, or about 0.5% / hour. After applying the drift compensation circuit, the zero drift may be reduced to the range of 0.03% / hour to 0.1% / hour, or about 0.05% / hour or less. Accordingly, continuous measurement may be possible for a range of 8 to 16 hours, or about 12 hours or more, without re-zero adjustment.

[0134] In one aspect of the present invention, the drift compensation circuit may include a chopper stabilization amplifier or an auto-zero amplifier.

[0135] In one embodiment, the chopper stabilized amplifier can remove the DC offset by modulating the input signal into a high-frequency signal, amplifying it, and then demodulating it. The chopper stabilized amplifier can periodically correct the offset according to the internal chopper frequency. The auto-zero amplifier can periodically measure the offset voltage through an internal sample-hold circuit and automatically correct it.

[0136] For example, the chopper frequency of the chopper stabilized amplifier may be in the range of 200 Hz to 800 Hz, or in the range of 300 Hz to 500 Hz, or about 400 Hz. The input offset voltage of the chopper stabilized amplifier may be in the range of 0.5 microvolts to 5 microvolts, or about 1 microvolt or less. The offset voltage drift may be in the range of 0.005 microvolts / °C to 0.02 microvolts / °C, or about 0.01 microvolts / °C or less. The input offset voltage of the auto-zero amplifier may be in the range of 0.5 microvolts to 2 microvolts, or about 1 microvolt or less. The drift component suppression ratio in the DC to 0.1 Hz band may be 60 dB or more, or 80 dB or more.

[0137] In one aspect of the present invention, the resistance network of the multiplication operation element 2 may include a ceramic substrate and a tantalum nitride thin film resistor formed on the ceramic substrate. Tantalum nitride may be denoted as TaN.

[0138] In one embodiment, the tantalum nitride thin film resistor may have a lower temperature coefficient and higher long-term stability compared to conventional variable resistors or carbon film resistors. The ceramic substrate may function as an insulating substrate on which the tantalum nitride thin film is deposited. The tantalum nitride thin film resistor may have high resistance to moisture and salt in an underwater environment.

[0139] For example, when a tantalum nitride thin film resistor is applied, the interference coefficient variation during continuous underwater operation for more than 6 months can be maintained within the range of ±0.2% to ±0.5%, or within approximately ±0.3%. When a conventional variable resistor is applied, under the same conditions, the interference coefficient variation can be within the range of ±1.5% to ±3%, or within approximately ±2% or more.

[0140] In one aspect of the present invention, the ceramic substrate may be an alumina substrate. Alumina may be denoted as Al2O3. The tantalum nitride thin film resistor may be formed by reactive magnetron sputtering.

[0141] In one embodiment, the alumina substrate has high thermal conductivity and excellent insulation properties, making it suitable as a substrate for a thin-film resistor. Reactive magnetron sputtering may be a process for forming a tantalum nitride thin film by using a tantalum target and introducing nitrogen as a reactive gas. Reactive magnetron sputtering can precisely control the composition and thickness of the thin film.

[0142] For example, the purity of the alumina substrate may be 96% or higher, or 99% or higher, or 99.6% or higher. The thickness of the alumina substrate may be in the range of 0.3 mm to 1.5 mm, or 0.5 mm to 1 mm, or about 0.635 mm. In the reactive magnetron sputtering process, the purity of the tantalum target may be 99.9% or higher, or 99.95% or higher. The flow rate ratio of argon to nitrogen may be in the range of 6:4 to 8:2, or about 7:3. The total process pressure may be in the range of 0.3 Pa to 1 Pa, or 0.4 Pa to 0.7 Pa, or about 0.5 Pa. The substrate temperature may be in the range of 250°C to 450°C, or 300°C to 400°C, or about 350°C. The DC power may be in the range of 200W to 500W, or in the range of 250W to 400W, or about 300W.

[0143] In one aspect of the present invention, the tantalum nitride thin film resistor has a thickness in the range of 80 nm to 200 nm, a sheet resistance in the range of 100 ohms / sq to 800 ohms / sq, and a temperature coefficient of ±25 ppm / ℃ or less.

[0144] In one embodiment, the thickness of the tantalum nitride thin film may be a factor determining the resistance value and the sheet resistance. The sheet resistance is the resistance value per unit area and may be a design parameter of the thin film resistance. The temperature coefficient is the rate of change of the resistance value with respect to temperature change and may be denoted as TCR.

[0145] For example, the thickness of the tantalum nitride thin film may be in the range of 100 nm to 180 nm, or in the range of 110 nm to 150 nm, or about 120 nm. The sheet resistance may be in the range of 150 ohms / sq to 600 ohms / sq, or in the range of 200 ohms / sq to 500 ohms / sq, or about 300 ohms / sq. The temperature coefficient may be ±20 ppm / ℃ or less, or ±15 ppm / ℃ or less, or ±10 ppm / ℃ or less. Compared to the temperature coefficient of conventional carbon film resistance, which is in the range of ±200 ppm / ℃ to ±500 ppm / ℃, the temperature stability may be improved.

[0146] In one aspect of the present invention, a protective layer formed on the surface of a tantalum nitride thin film resistor may be further included. The protective layer can protect the tantalum nitride thin film resistor from the external environment.

[0147] In one embodiment, the protective layer can ensure long-term stability of the tantalum nitride thin film resistor by blocking moisture and ion penetration. The protective layer can be formed of a chemically inert material. The protective layer can perform a physical protection function without affecting the electrical characteristics of the tantalum nitride thin film resistor.

[0148] For example, in the absence of a protective layer, the change in resistance value after 3 to 6 months in an underwater environment may be in the range of ±0.5% to ±1.5%. In the presence of a protective layer, under the same conditions, the change in resistance value may be reduced to the range of ±0.1% to ±0.3%, or to about ±0.2% or less.

[0149] In one aspect of the present invention, the protective layer may be an yttria layer. Yttria may be denoted as Y2O3. The thickness of the yttria layer may be in the range of 10 nm to 50 nm.

[0150] In one embodiment, yttria may be a rare earth oxide with high chemical inertness and excellent moisture barrier properties. The yttria layer may be formed by electron beam deposition or sputtering. The thickness of the yttria layer may be set considering the protective function and process efficiency.

[0151] For example, the thickness of the yttria layer may be in the range of 15 nm to 40 nm, or in the range of 20 nm to 35 nm, or about 25 nm. In the electron beam deposition process, the deposition rate may be in the range of 0.3 Angstroms / s to 1 Angstrom / s, or about 0.5 Angstroms / s. The substrate temperature may be in the range of 150°C to 300°C, or in the range of 180°C to 250°C, or about 200°C. The moisture transmittance of the yttria layer is 10 {-3} g / m 2 / day or less, or 10 {-4} g / m 2 It can be less than / day.

[0152] In one aspect of the present invention, the resistance of the tantalum nitride thin film may be adjusted by laser trimming. Laser trimming may be performed by an Nd:YAG laser.

[0153] In one embodiment, laser trimming may be a process for fine-tuning the resistance value by selectively removing a portion of the tantalum nitride thin film. The Nd:YAG laser is a solid-state laser with a wavelength of 1064 nm and may be suitable for precise thin film processing. Laser trimming is an interference coefficient C according to the calibration test results. ij It can be precisely adjusted to the corresponding resistance value.

[0154] For example, the wavelength of the Nd:YAG laser may be 1064 nm. The pulse width may be in the range of 5 ns to 20 ns, or in the range of 8 ns to 15 ns, or approximately 10 ns. The repetition rate may be in the range of 5 kHz to 20 kHz, or in the range of 8 kHz to 15 kHz, or approximately 10 kHz. The spot size may be in the range of 15 micrometers to 40 micrometers, or in the range of 20 micrometers to 30 micrometers, or approximately 25 micrometers. The precision of the resistance value after laser trimming may be ±0.2% or less, or ±0.1% or less, or ±0.05% or less. An L-cut pattern or a serpentine cut pattern may be applied.

[0155] In one aspect of the present invention, the interference cancellation computing device 200 may further include a magnetic shielding housing that accommodates an interference cancellation computing circuit 6. The magnetic shielding housing can protect the interference cancellation computing circuit 6 from external electromagnetic disturbances.

[0156] In one embodiment, the magnetic shielding housing can block electromagnetic noise generated in a water tank test environment. In the water tank test environment, sources of electromagnetic noise such as towing vehicle motors, wave generators, and inverters may be present. The magnetic shielding housing can prevent such external electromagnetic disturbances from affecting the interference cancellation calculation circuit 6.

[0157] For example, in the absence of a magnetic shielding housing, the measurement error due to external electromagnetic noise may be in the range of ±0.5% to ±2%. When a magnetic shielding housing is applied, the measurement error may be reduced to the range of ±0.05% to ±0.2%, or to about ±0.1% or less. The internal dimensions of the magnetic shielding housing may be in the range of width 50mm to 100mm, height 40mm to 80mm, and length 20mm to 50mm.

[0158] In one aspect of the present invention, the magnetic shielding housing may be formed of a nanocrystalline soft magnetic alloy. The nanocrystalline soft magnetic alloy may be a soft magnetic material having nanometer-sized crystal grains.

[0159] In one embodiment, the nanocrystalline soft magnetic alloy may be a material in which nano-sized crystal grains are formed by heat-treating an amorphous alloy. The nanocrystalline soft magnetic alloy may be suitable as a magnetic shielding material because it has high permeability and low coercivity. The nanocrystalline soft magnetic alloy may have superior magnetic shielding performance compared to conventional silicon steel sheets or permalloy.

[0160] For example, the magnetic shielding effect of the nanocrystalline soft magnetic alloy may be 50 dB or more, or 60 dB or more, or 70 dB or more in the 50 Hz to 10 kHz band. Compared to the magnetic shielding effect of conventional silicon steel sheets, which is in the range of 20 dB to 40 dB in the same band, the shielding performance may be improved.

[0161] In one aspect of the present invention, the nanocrystalline soft magnetic alloy may be an Fe-Si-B-Nb-Cu alloy. The nanocrystalline soft magnetic alloy may be formed by a stack of amorphous ribbons and heat treatment.

[0162] In one embodiment, the Fe-Si-B-Nb-Cu alloy may be an alloy comprising iron as the main component and silicon, boron, niobium, and copper. The amorphous ribbon may be a thin strip-shaped amorphous material manufactured by a rapid solidification method. A nanocrystalline structure may be formed by stacking the amorphous ribbons and heat treating them.

[0163] For example, the composition of an Fe-Si-B-Nb-Cu alloy is Fe {73.5} Si {13.5} It could be B9Nb3Cu1. In the rapid solidification method, the cooling rate is 10 5 K / s or more, or 10 6It may be K / s or higher. The roll surface speed may be in the range of 20 m / s to 50 m / s, or in the range of 25 m / s to 40 m / s, or about 30 m / s. The thickness of the amorphous ribbon may be in the range of 10 micrometers to 30 micrometers, or in the range of 15 micrometers to 25 micrometers, or about 18 micrometers. The width of the amorphous ribbon may be in the range of 10 mm to 50 mm, or in the range of 20 mm to 30 mm, or about 25 mm. The number of layers of the amorphous ribbon may be in the range of 3 to 15 layers, or in the range of 5 to 10 layers. The heat treatment temperature may be in the range of 480°C to 600°C, or in the range of 520°C to 570°C, or about 540°C. The heat treatment time may be in the range of 0.5 hours to 2 hours, or about 1 hour. The heat treatment atmosphere can be a nitrogen atmosphere or an argon atmosphere.

[0164] In one aspect of the present invention, the nanocrystalline soft magnetic alloy may have an average grain size in the range of 5 nm to 25 nm and an initial permeability of 50,000 or more.

[0165] In one embodiment, the average grain size can be determined according to heat treatment conditions, and a structure in which nanometer-sized grains are dispersed within an amorphous matrix can be formed. Initial permeability is the ratio of the change in magnetic flux density to the change in magnetic field, and the larger the value, the better the magnetic shielding performance.

[0166] For example, the average grain size may be in the range of 8 nm to 20 nm, or in the range of 10 nm to 18 nm, or about 12 nm. The initial permeability may be 60,000 or more, or 80,000 or more, or 100,000 or more. The saturation magnetic flux density may be in the range of 1.0 T to 1.5 T, or in the range of 1.1 T to 1.35 T, or about 1.24 T. The coercivity may be 2 A / m or less, or 1 A / m or less, or 0.5 A / m or less. Due to these characteristics, 60 Hz noise of the towing vehicle motor and several kHz noise of the inverter can be effectively shielded in a water tank test environment, and the signal-to-noise ratio of the interference cancellation calculation circuit 6 can be improved by 15 dB or more, or 20 dB or more.

[0167] In one aspect of the present invention, the drift compensation circuit may further include a high-pass filter. The high-pass filter may include a supercapacitor.

[0168] In one embodiment, the high-pass filter can block low-frequency drift components and pass components of the measurement signal band. A supercapacitor is an energy storage device having a large capacitance and can be used to set a large time constant of the high-pass filter. By using a supercapacitor, distortion of the measurement signal can be minimized while effectively blocking low-frequency drift components.

[0169] For example, the cutoff frequency of the high-pass filter may be 0.001 Hz or less, or 0.0005 Hz or less, or about 0.0003 Hz. Low-frequency drift components below the cutoff frequency may be attenuated by 20 dB or more, or 40 dB or more. Signal attenuation may be 0.1 dB or less in the measurement signal band range of 0.1 Hz to 100 Hz.

[0170] In one aspect of the present invention, the supercapacitor may include an ionic liquid electrolyte. The ionic liquid electrolyte may have superior temperature stability compared to conventional aqueous or organic electrolytes.

[0171] In one embodiment, the ionic liquid may be composed of cations and anions as a salt that is in a liquid state at room temperature. The ionic liquid electrolyte can maintain a liquid state over a wide temperature range. The ionic liquid electrolyte has a low vapor pressure, so there may be no performance degradation due to evaporation.

[0172] For example, a supercapacitor with an ionic liquid electrolyte may have a capacitance variation of ±5% or less, or ±3% or less, in the range of -20°C to 60°C, or in the range of -40°C to 80°C. A conventional aqueous electrolyte supercapacitor may have a capacitance variation of ±15% to ±25% in the same temperature range. The thermal decomposition temperature of the ionic liquid may be 300°C or higher, or 400°C or higher.

[0173] In one aspect of the present invention, the ionic liquid electrolyte may comprise an imidazolium-based cation and a non-trifluoromethanesulfonylimide anion. The non-trifluoromethanesulfonylimide may be abbreviated as TFSI.

[0174] In one embodiment, the imidazolium-based cation may have a structure in which an alkyl group is substituted on an imidazole ring. The non-trifluoromethanesulfonylimide anion may have a structure in which a trifluoromethyl group is bonded to a sulfonamide structure. The combination of the imidazolium-based cation and the non-trifluoromethanesulfonylimide anion can provide high ionic conductivity and electrochemical stability.

[0175] For example, the ionic conductivity may be 5 mS / cm or higher, or 8 mS / cm or higher, or 10 mS / cm or higher. The electrochemical stable potential window may be 3 V or higher, or 4 V or higher, or 4.5 V or higher. The viscosity may be in the range of 20 mPa·s to 50 mPa·s, or in the range of 25 mPa·s to 40 mPa·s.

[0176] In one aspect of the present invention, the ionic liquid electrolyte may be 1-ethyl-3-methylimidazolium bistrifluoromethanesulfonylimide. 1-ethyl-3-methylimidazolium bistrifluoromethanesulfonylimide may be abbreviated as EMIM-TFSI.

[0177] In one embodiment, EMIM-TFSI may be composed of a cation in which an ethyl group and a methyl group are substituted at positions 1 and 3 of an imidazole ring, and a non-trifluoromethanesulfonylimide anion. EMIM-TFSI may have reproducible properties as a commercially available ionic liquid.

[0178] For example, the molecular formula of EMIM-TFSI is C8H {11} It may be F6N3O4S2. The molecular weight may be in the range of 391 g / mol to 392 g / mol, or about 391.31 g / mol. The purity may be 98% or higher, or 99% or higher. The CAS number may be 174899-82-2. The ionic conductivity at 25°C may be in the range of 8 mS / cm to 10 mS / cm, or about 8.8 mS / cm. The melting point may be -15°C or lower, or -20°C or lower. The thermal decomposition temperature may be 350°C or higher, or 400°C or higher.

[0179] In one aspect of the present invention, the supercapacitor may include an electrode composed of a composite of activated carbon and a carbon-based conductive material. The time constant of the high-pass filter may be in the range of 100 seconds to 1,000 seconds.

[0180] In one embodiment, the activated carbon has a high specific surface area and can provide capacitance through the formation of an electric double layer. The carbon-based conductive material can improve the conductivity of the electrode by forming electrical connections between the activated carbon particles. The time constant is the product of resistance and capacitance, which can determine the cutoff frequency of the high-pass filter.

[0181] For example, the specific surface area of ​​activated carbon is 1,500 m² 2 / g or more, or 2,000m 2 / g or more, or 2,500m 2 It may be greater than / g. The carbon-based conductive material may be carbon black or graphene. The mass ratio of activated carbon to the carbon-based conductive material may be in the range of 80:15 to 90:5, or about 85:10. Polyvinylidene fluoride may be included as a binder in the range of 3% to 10%, or about 5%. The electrode thickness may be in the range of 50 micrometers to 200 micrometers, or in the range of 80 micrometers to 150 micrometers, or about 100 micrometers. The capacitance of the supercapacitor may be in the range of 1F to 100F, or in the range of 5F to 50F, or about 10F. The equivalent series resistance may be in the range of 10 milliohms to 100 milliohms, or in the range of 30 milliohms to 70 milliohms, or about 50 milliohms. The rated voltage may be in the range of 2V to 3V, or about 2.5V. The time constant of the high-pass filter may be in the range of 200 seconds to 800 seconds, or in the range of 300 seconds to 700 seconds, or about 500 seconds. Accordingly, zero drift may be reduced to the range of 0.01% / hour to 0.05% / hour, or about 0.02% / hour or less, and continuous measurement may be possible for 20 to 30 hours, or about 24 hours or more, without zero adjustment.

[0182] In one aspect of the present invention, the interference cancellation computing device 200 may further include a substrate on which an interference cancellation computing circuit 6 is mounted and an active vibration cancellation unit laminated on the substrate. The active vibration cancellation unit can cancel out microphonic noise caused by mechanical vibration of the substrate.

[0183] In one embodiment, vibrations of the force meter caused by flow may occur during a water tank test, and separately, mechanical vibrations of the interference cancellation calculation circuit 6 itself may induce microphonic noise in the circuit elements. Microphonic noise may be electrical noise generated by mechanical deformation of resistors, capacitors, wiring, etc. The active vibration cancellation unit can eliminate microphonic noise by detecting vibrations of the substrate and canceling them out with an inverse phase signal.

[0184] For example, in the absence of an active vibration cancellation unit, the measurement error due to microphonic noise under flow conditions may be in the range of ±0.3% to ±1%. When an active vibration cancellation unit is applied, the measurement error may be reduced to a range of ±0.03% to ±0.1%, or to approximately ±0.05% or less.

[0185] In one aspect of the present invention, the active vibration cancellation unit may include an acceleration sensor attached to a substrate, a piezoelectric actuator laminated on the substrate, and a feedback control circuit connected to the acceleration sensor and the piezoelectric actuator.

[0186] In one embodiment, the acceleration sensor can detect vibration of the substrate and output an electrical signal corresponding to the vibration. The piezoelectric actuator can generate mechanical displacement when voltage is applied to cancel out vibration of the substrate. The feedback control circuit can apply an inverse phase driving signal to the piezoelectric actuator based on the output of the acceleration sensor.

[0187] For example, the vibration suppression band may be in the range of DC to 500 Hz or DC to 1 kHz. The vibration damping ratio may be 10 dB or more, 20 dB or more, or 30 dB or more. The delay time of the feedback control loop may be 1 ms or less, 0.5 ms or less, or 0.1 ms or less.

[0188] In one aspect of the present invention, the acceleration sensor may be a MEMS acceleration sensor. MEMS may be an abbreviation for Micro Electro Mechanical Systems.

[0189] In one embodiment, the MEMS accelerometer may be a small accelerometer manufactured by a semiconductor process. The MEMS accelerometer may be small and have high sensitivity and a wide bandwidth. The MEMS accelerometer may be mounted directly on a substrate, making installation easy.

[0190] For example, the sensitivity of the MEMS accelerometer may be in the range of 100 mV / g to 500 mV / g, or in the range of 200 mV / g to 400 mV / g, or about 300 mV / g. The bandwidth may be in the range of DC to 1 kHz, or in the range of DC to 2 kHz, or in the range of DC to 1.6 kHz. The measurement range may be in the range of ±2 g to ±10 g, or in the range of ±3 g to ±6 g. The noise density may be 100 microg / √Hz or less, or 50 microg / √Hz or less. The external dimensions may be 4 mm × 4 mm × 1.5 mm or less, or 5 mm × 5 mm × 2 mm or less.

[0191] In one aspect of the present invention, the piezoelectric actuator may include a piezoelectric single crystal. The piezoelectric single crystal may have superior piezoelectric properties compared to polycrystalline piezoelectric ceramics.

[0192] In one embodiment, the piezoelectric single crystal may be a piezoelectric material in which the crystal orientation is uniformly aligned. The piezoelectric single crystal may have a higher piezoelectric constant and electromechanical coupling coefficient compared to polycrystalline piezoelectric ceramics. The piezoelectric single crystal may enable precise control of micro-displacements.

[0193] For example, the piezoelectric constant d of a piezoelectric single crystal 33 This can be more than 3 times, 4 times, or 5 times greater than that of polycrystalline PZT ceramic. Electromechanical coupling coefficient k 33 This can be 0.85 or higher, or 0.90 or higher. By using a piezoelectric single crystal, a larger displacement can be generated at the same driving voltage, or the same displacement can be generated at a lower driving voltage.

[0194] In one aspect of the present invention, the piezoelectric single crystal may be a lead magnesium niobate-lead titanate single crystal. Lead magnesium niobate-lead titanate has the chemical formula PbMg {1 / 3} Nb {2 / 3} It can be a solid solution of O3 and PbTiO3 and can be abbreviated as PMN-PT. The piezoelectric single crystal has a piezoelectric constant d 33 It can be 1,500 pC / N or higher.

[0195] In one embodiment, the PMN-PT single crystal can be grown by the Bridgman method or the solid-state reaction method. The PMN-PT single crystal can be cut in a specific crystal direction and used, and the 001 direction may have excellent piezoelectric properties. The PMN-PT single crystal may have high piezoelectric responsiveness compared to conventional PZT ceramics.

[0196] For example, the composition ratio of the PMN-PT single crystal may be in the range of 0.65 PMN-0.35 PT to 0.70 PMN-0.30 PT, or approximately 0.67 PMN-0.33 PT. Piezoelectric constant d 33 g may be 1,800 pC / N or greater, or 2,000 pC / N or greater, or 2,500 pC / N or greater. Electromechanical coupling coefficient k 33g can be 0.90 or greater, or 0.92 or greater, or 0.94 or greater. Dielectric constant ε 33 The value may be 4,000 or more, or 5,000 or more, or 6,000 or more. The crystal direction may be the 001 direction. The thickness of the PMN-PT single crystal may be in the range of 0.3 mm to 1 mm, or in the range of 0.4 mm to 0.7 mm, or about 0.5 mm. The area may be in the range of 10 mm × 10 mm to 30 mm × 30 mm, or in the range of 15 mm × 15 mm to 25 mm × 25 mm, or about 20 mm × 20 mm.

[0197] In one aspect of the present invention, the feedback control circuit may include an analog PID controller. A high-voltage amplifier connected to the feedback control circuit may be further included.

[0198] In one embodiment, the analog PID controller may be an analog circuit that performs proportional, integral, and derivative control operations. The analog PID controller may receive the output of an acceleration sensor and generate a driving signal for a piezoelectric actuator. A high-voltage amplifier may amplify the output of the analog PID controller to a voltage level required for driving the piezoelectric actuator.

[0199] For example, the proportional gain K of an analog PID controller p α can be in the range of 5 to 20, or in the range of 8 to 15, or about 10. Integration time constant T i α may be in the range of 0.05 ms to 0.5 ms, or in the range of 0.08 ms to 0.2 ms, or approximately 0.1 ms. The differential time constant T dThe range may be 0.005 ms to 0.05 ms, or 0.008 ms to 0.02 ms, or about 0.01 ms. The output voltage range of the high-voltage amplifier may be 0 V to 100 V, or 0 V to 150 V, or 0 V to 200 V. The bandwidth of the high-voltage amplifier may be 1 kHz or more, or 5 kHz or more, or 10 kHz or more. Accordingly, the signal-to-noise ratio at high-frequency oscillations of 100 Hz or more may be improved by 10 dB or more, or 15 dB or more, or 20 dB or more.

[0200] In one aspect of the present invention, the interference cancellation calculation system may be for eliminating interference between force components of a multi-component force system that simultaneously measures a plurality of force components acting on an object. The interference cancellation calculation system may be composed of a plurality of modules to perform respective calculation functions.

[0201] In one embodiment, the interference cancellation operation system may include a signal input module, a multiplication operation module, a summation operation module, and an amplification operation module. The signal input module may receive an output signal 1 from the Wheatstone bridge circuit of a multi-component system. The multiplication operation module may be connected to the signal input module and may generate an interference correction signal by applying an interference coefficient to the output signal 1. The summation operation module may be connected to the signal input module and the multiplication operation module and may generate an interference cancellation signal by summing the output signal 1 and the interference correction signal. The amplification operation module may be connected to the summation operation module and may generate an interference separation output signal 5 by amplifying the interference cancellation signal.

[0202] For example, as shown in FIG. 2, the multiplication operation module can correspond to a signal multiplying processor, the summing operation module can correspond to a summing processor, and the amplification operation module can correspond to a signal amplifying processor. Through the interference removal operation system, six component signals of Fx, Fy, Fz, Mx, My, and Mz can be output in a state where interference is removed.

[0203] In one aspect of the present invention, a multiplication operation module may include a resistance network comprising a variable resistor or a fixed resistor, and a buffer amplifier connected to the resistance network.

[0204] In one embodiment, the resistance network can perform the function of multiplying the output signal 1 by an interference coefficient. The buffer amplifier can buffer the output of the resistance network to transmit the signal without affecting the subsequent circuit. The buffer amplifier may have a high input impedance and a low output impedance.

[0205] For example, the input impedance of the buffer amplifier may be 1 megaohm or more, or 10 megaohms or more. The output impedance may be 100 ohms or less, or 50 ohms or less. The gain of the buffer amplifier may be 1x or unity gain.

[0206] In one aspect of the present invention, the interference cancellation operation system may further include a temperature compensation module connected to a multiplication operation module. The temperature compensation module may include a thermistor and an analog multiplier connected to the thermistor.

[0207] In one embodiment, the temperature compensation module can compensate for changes in the characteristics of the resistance network due to changes in the temperature of the water bath test environment. The thermistor can detect the ambient temperature and output a signal corresponding to the temperature. The analog multiplier can apply a temperature-dependent correction factor to the output signal 1 in real time.

[0208] For example, the temperature-dependent variation of the interference coefficient in the range of water temperature from 5°C to 30°C can be compensated to within ±0.5% by a temperature compensation module.

[0209] In one aspect of the present invention, the interference cancellation operation system may further include a non-linear correction module connected to the downstream end of the summation operation module. The non-linear correction module may include a diode function generator.

[0210] In one embodiment, the nonlinear correction module can correct the nonlinear interference component remaining after linear interference removal. The diode function generator can implement a nonlinear function using a combination of multiple diodes and resistors.

[0211] For example, nonlinear interference occurring in large deformation regions can be corrected to within ±1% by a nonlinear correction module.

[0212] In one aspect of the present invention, the interference cancellation operation system may further include a drift compensation module connected to the downstream end of the amplification operation module. The drift compensation module may include a chopper stabilization amplifier or an auto-zero amplifier.

[0213] In one embodiment, the drift compensation module can eliminate DC offset and low-frequency drift components that occur during long-term measurement. The chopper stabilized amplifier or auto-zero amplifier may have excellent long-term stability due to low input offset voltage and offset drift.

[0214] For example, the zero drift can be reduced to 0.05% / hour or less by the drift compensation module, allowing for continuous measurement for more than 12 hours.

[0215] In one aspect of the present invention, the resistance network of the multiplication operation module may include a tantalum nitride thin film resistor formed on a ceramic substrate.

[0216] In one embodiment, the tantalum nitride thin film resistor may be suitable for long-term operation in an underwater environment due to its low temperature coefficient and high long-term stability. The tantalum nitride thin film resistor may be formed on an alumina substrate by reactive magnetron sputtering.

[0217] For example, the temperature coefficient of resistance of the tantalum nitride thin film can be ±15 ppm / ℃ or less, and the interference coefficient variation can be maintained within ±0.3% during underwater operation for more than 6 months.

[0218] In one aspect of the present invention, the interference cancellation operation system may further include a magnetic shielding housing that accommodates a multiplication operation module, a summation operation module, and an amplification operation module. The magnetic shielding housing may be formed of a nanocrystalline soft magnetic alloy.

[0219] In one embodiment, the magnetic shielding housing can protect each module of the interference cancellation computing system from external electromagnetic noise in a water bath test environment. The nanocrystalline soft magnetic alloy has high permeability and low coercivity, so it can have excellent magnetic shielding performance.

[0220] For example, a shielding effect of 60 dB or more in the 50 Hz to 10 kHz band can be obtained by a nanocrystalline soft magnetic alloy magnetic shielding housing, and the signal-to-noise ratio can be improved by 20 dB or more.

[0221] In one aspect of the present invention, the drift compensation module may further include a supercapacitor comprising an ionic liquid electrolyte and a high-pass filter comprising said supercapacitor.

[0222] In one embodiment, a supercapacitor comprising an ionic liquid electrolyte can have stable capacitance characteristics over a wide temperature range. A high-pass filter can effectively block low-frequency drift components by utilizing the large capacitance of the supercapacitor.

[0223] For example, EMIM-TFSI can be used as the ionic liquid electrolyte, the time constant of the high-pass filter can be in the range of 100 seconds to 1,000 seconds, and the zero drift can be reduced to 0.02% / hour or less, enabling continuous measurement for more than 24 hours.

[0224] In one aspect of the present invention, the interference cancellation operation system may further include a substrate on which a multiplication operation module, a summation operation module, and an amplification operation module are mounted, and an active vibration cancellation unit laminated on said substrate. The active vibration cancellation unit may include an acceleration sensor, a piezoelectric actuator including a piezoelectric single crystal, and a feedback control circuit including an analog PID controller.

[0225] In one embodiment, the active vibration cancellation unit can cancel out microphonic noise caused by mechanical vibration of the substrate in real time. An acceleration sensor detects vibration of the substrate, a piezoelectric actuator generates an inverse phase displacement, and a feedback control circuit can perform closed-loop control.

[0226] For example, a PMN-PT single crystal can be used as a piezoelectric single crystal, and the piezoelectric constant d 33 The signal-to-noise ratio can be improved by more than 15 dB at high frequency vibrations of 100 Hz or higher by the active vibration cancellation unit, and the measurement error caused by microphonic noise can be reduced to ±0.05% or less even under flow conditions.

[0227] The present invention will be described in detail below using specific embodiments. It should be understood that the following embodiments are not intended to limit the scope of the invention, but are intended to illustrate the practice of the invention.

[0228] Example 1

[0229] To verify the effect of the interference removal computing device 200 according to the present invention, an example was constructed targeting a 6-component force meter installed inside a slender underwater vehicle model.

[0230] The slender underwater vehicle model used in this embodiment had a diameter of 0.32 m and a length of 3.2 m, with an aspect ratio of 10:1 and a weight of approximately 150 kg. The sensor installation space inside the model was limited to a cylindrical space with a diameter of 175 mm and a length of 400 mm. Since this narrow installation space makes it structurally difficult to eliminate interference, the interference cancellation computing device 200 of the present invention was applied.

[0231] The measuring capacities of the 6-component force meter were set as follows. The axial force Fx was set to 3,000 N, the lateral force Fy to 3,000 N, and the vertical force Fz to 12,000 N. The roll moment Mx was set to 1,000 Nm, the pitch moment My to 2,000 Nm, and the yaw moment Mz to 2,000 Nm.

[0232] Aluminum Al 2024-T3 was used as the material for the sensing part of the 6-component force meter. The yield stress of Al 2024-T3 is 345 MPa, and the design safety factor was set to 3.7 to design based on an allowable stress of 96 MPa.

[0233] As shown in FIG. 1, six force component signals, Fx, Fy, Fz, Mx, My, and Mz, were output to the data logger from the six force component meter. As shown in FIG. 2, the interference cancellation operation device 200 received the force component output signal 1 and sequentially passed through a multiplication operation element 2, a summation operation element 3, and an amplification operation element 4 to output an interference separation output signal 5.

[0234] Using calibration constants obtained from the calibration test of the force component, the relationship between the force component and the output was expressed as a dimensionless system of linear equations as shown in Equation 1. In Equation 1, subscripts 1, 2, and 3 represent Fx, Fy, and Fz, respectively, and subscripts 4, 5, and 6 represent Mx, My, and Mz. Interference coefficient C ij In this, the first subscript i indicates the direction of the measured load, and the second subscript j indicates the applied load. S ni is the output signal appearing in the sensor due to the i-direction load, and the output signal a at the maximum load. ii It was a dimensionless signal.

[0235] In cases where only the interference between specific components exceeds the allowable range, a simplified relationship as shown in Equation 2 was applied. In Equation 2, the interference coefficient C between F2 and F4. 24 and C 42 Only the case where the allowable range was exceeded was exemplified, and the remaining interference terms were ignored.

[0236] Multiplication element 2 used a 10-turn precision potentiometer, with a resistance range of 10 kilohms and a resistance precision of ±0.05%. Summing element 3 was constructed as an inverting adder circuit using an operational amplifier with a gain bandwidth of 10 MHz, and the precision of the input resistance and feedback resistance was ±0.1%. Amplification element 4 used a low-noise operational amplifier with an input offset voltage of 10 microvolts or less, and the gain was set to 10 times.

[0237] As a result of calibration tests prior to the application of the interference cancellation computing unit 200, the following major interferences occurred due to design conditions and machining errors. In the Fx channel, interference caused by the My component was -25.0%. In the Fy channel, interference caused by the Mz component was 10.8%. In the Fz channel, interference caused by the My component was -17.0%, and interference caused by the Mx component was 6.1%.

[0238] Items with an absolute interference coefficient of 3% or less were excluded from the circuit configuration to optimize circuit simplicity and signal-to-noise ratio.

[0239] When the interference cancellation unit 200 was connected to the Wheatstone bridge output terminal of the 6-component force meter and the circuit was configured according to the sequential elimination method, the interference was reduced as follows. The interference of the Fx channel decreased from -25.0% to 2.4%. The interference of the Fy channel decreased from 10.8% to 0.6%. Interference between all components was controlled to less than 3%, which is the normal allowable limit.

[0240] In this embodiment, since the output signal 1 was not digitized through the interference removal calculation device 200 and the calculation was performed in an analog signal state, it was confirmed that the continuity of the signal was maintained and it is applicable to the measurement of dynamic phenomena. Even when high-frequency load fluctuations of several hundred Hz or higher occurred, a waveform with interference removed was output without phase delay.

[0241] Example 2

[0242] A temperature compensation circuit was added to the interference removal computing device 200 of Example 1 to compensate for changes in characteristics due to temperature changes in a water tank test environment.

[0243] In this embodiment, a temperature compensation circuit was added to the multiplication element 2. The temperature compensation circuit included a temperature detector and an analog multiplier. The temperature detector was composed of a platinum thermistor Pt100 and a Wheatstone bridge circuit.

[0244] The resistance of Pt100 at 0°C was 100 ohms, and the temperature coefficient was +3,850 ppm / °C. At a water temperature of 5°C, the resistance of Pt100 was 101.95 ohms, and at a water temperature of 30°C, the resistance was 111.67 ohms. The output voltage range of the bridge circuit was 0 mV to 50 mV, corresponding to a water temperature range of 5°C to 30°C.

[0245] A 4-quadrant analog multiplier was used. The bandwidth of the 4-quadrant analog multiplier was 1 MHz. An output signal 1 was applied to the X input, and the output voltage of the temperature detector was applied to the Y input. The range of the correction factor corresponding to the temperature was 0.98 to 1.02.

[0246] When the temperature compensation circuit was not applied, the variation in the interference coefficient was ±2.5% in the water temperature range of 5°C to 30°C. When the temperature compensation circuit was applied, the variation in the interference coefficient in the same water temperature range was reduced to ±0.5% or less.

[0247] In this embodiment, by adding a temperature compensation circuit, changes in the characteristics of the resistance network due to temperature changes in the water tank test environment were compensated in real time, and the long-term operational stability of the interference removal computing device 200 was improved.

[0248] Example 3

[0249] A nonlinear correction circuit was added to the interference removal computing device 200 of Example 1 to correct the nonlinear interference component occurring in the large deformation region.

[0250] In this embodiment, a non-linear correction circuit was added to the end of the summing operation element 3. The non-linear correction circuit included a diode function generator.

[0251] The diode function generator was constructed with eight diodes and a resistor connected in series with each diode. Small-signal diodes with a forward voltage drop of 0.65 V were used. The diode breakpoint voltage interval was 0.5 V. The total number of approximation intervals was nine.

[0252] The diode function generator has an input voltage V i Output voltage V for o ul V o = V i + kx V i 2A second-order correction was performed in the form of . The correction factor k was adjusted with a trimmer resistor, and the adjustment range was -0.05 to +0.05.

[0253] Non-linear interference occurred in the large deformation region of more than 20% relative to the rated output of the measurement range. Before the application of the non-linear correction circuit, the non-linear interference was ±3%, and after the application of the non-linear correction circuit, the non-linear interference decreased to ±1% or less.

[0254] In this embodiment, by adding a non-linear correction circuit, the higher-order interference component remaining after linear interference removal based on Equation 1 was effectively corrected, and the precision of interference removal was improved across the entire measurement range.

[0255] Example 4

[0256] A drift compensation circuit was added to the interference removal computing device 200 of Example 1 to eliminate DC offset and low-frequency drift components that occur during long-term measurement.

[0257] In this embodiment, a drift compensation circuit was added to the output of the amplification operation element 4. The drift compensation circuit included a chopper stabilized amplifier.

[0258] The chopper frequency of the chopper stabilized amplifier was 400 Hz. The input offset voltage of the chopper stabilized amplifier was 1 microvolt or less, and the offset voltage drift was 0.01 microvolt / °C or less. The drift component suppression ratio in the DC to 0.1 Hz band was 80 dB or more.

[0259] Before applying the drift compensation circuit, the zero drift was 0.5% / hour. After applying the drift compensation circuit, the zero drift decreased to 0.05% / hour or less.

[0260] In this embodiment, continuous measurement for more than 12 hours without zero point adjustment was possible by adding a drift compensation circuit. The interference cancellation computing device 200 was effectively applied to the precise measurement of dynamic load changes over a long period of time in a water tank test.

[0261] Example 5

[0262] In the interference removal computing device 200 of Example 1, the resistance network of the multiplication computing element 2 was configured with tantalum nitride thin film resistors to improve long-term underwater operation stability.

[0263] In this embodiment, the resistance network of the multiplication operation element 2 was composed of a tantalum nitride thin film resistor formed on an alumina substrate. The purity of the alumina substrate was 99.6%, and the thickness was 0.635 mm.

[0264] The resistance of the tantalum nitride thin film was formed by reactive DC magnetron sputtering. The purity of the tantalum target was 99.95%. The flow rate ratio of argon to nitrogen was 7:3, and the total process pressure was 0.5 Pa. The substrate temperature was 350°C, the DC power was 300 W, and the deposition time was 30 minutes.

[0265] The thickness of the formed tantalum nitride thin film was 120 nm, the sheet resistance was 300 ohms / sq, and the temperature coefficient was ±15 ppm / ℃.

[0266] Patterning of the tantalum nitride thin film resistors was performed using photolithography and reactive ion etching. AZ1512 was used as the photoresist, and the exposure dose was 100 mJ / cm². 2 It was. Reactive ion etching used an SF6 / Ar mixed gas.

[0267] A yttria protective layer was formed on the surface of a tantalum nitride thin film resistor. The yttria protective layer was formed by electron beam deposition, with a deposition rate of 0.5 angstroms / s and a substrate temperature of 200°C. The thickness of the yttria protective layer was 25 nm.

[0268] The resistance of the tantalum nitride thin film was precisely adjusted by Nd:YAG laser trimming. The wavelength of the Nd:YAG laser was 1064 nm, the pulse width was 10 ns, and the repetition rate was 10 kHz. The spot size was 25 micrometers. The precision of the resistance value after laser trimming was ±0.05%.

[0269] When a conventional variable resistor was applied, the interference coefficient variation was ±2% during 6 months of underwater operation. When the tantalum nitride thin film resistor of this embodiment was applied, the interference coefficient variation was maintained within ±0.3% under the same conditions.

[0270] In this embodiment, the long-term underwater operation reliability of the interference cancellation computing device 200 is improved by applying a tantalum nitride thin film resistor, and the stability of the resistance value in a humid and salty environment is ensured.

[0271] Example 6

[0272] A magnetic shielding housing formed of a nanocrystalline soft magnetic alloy was added to the interference cancellation computing device 200 of Example 1 to protect the interference cancellation computing circuit 6 from external electromagnetic disturbances.

[0273] In this embodiment, a magnetic shielding housing accommodating the interference cancellation operation circuit 6 was fabricated from a nanocrystalline soft magnetic alloy. The internal dimensions of the magnetic shielding housing were 80 mm in width, 60 mm in height, and 30 mm in length.

[0274] The nanocrystalline soft magnetic alloy used was an Fe-Si-B-Nb-Cu-based alloy, and the composition was Fe {73.5} Si {13.5} It was B9Nb3Cu1. The nanocrystalline soft magnetic alloy was formed by stacking amorphous ribbons and heat treatment.

[0275] Amorphous ribbon was manufactured by the single-roll rapid solidification method. The cooling rate was 10 6 It was K / s, and the roll surface speed was 30 m / s. The thickness of the amorphous ribbon was 18 micrometers, and the width was 25 mm.

[0276] Seven layers of amorphous ribbon were stacked and then heat-treated in a nitrogen atmosphere. The heat treatment temperature was 540°C, and the heat treatment time was 1 hour. Nanometer-sized crystal grains were formed within the amorphous matrix by the heat treatment.

[0277] After heat treatment, the average grain size of the nanocrystalline soft magnetic alloy was 12 nm. The initial permeability was 90,000, the saturation magnetic flux density was 1.24 T, and the coercivity was 0.8 A / m.

[0278] In the absence of a magnetic shielding housing, the measurement error due to electromagnetic noise from the towing vehicle motor and inverter in the water tank test environment was ±1%. When a nanocrystalline soft magnetic alloy magnetic shielding housing was applied, the shielding effect was 60dB in the 50Hz to 10kHz band, and the measurement error was reduced to ±0.1% or less.

[0279] In this embodiment, the signal-to-noise ratio of the interference cancellation calculation circuit 6 was improved by 20dB by applying a nanocrystalline soft magnetic alloy magnetic shielding housing, and precise interference cancellation calculation was possible even in a water bath test environment with a poor electromagnetic environment.

[0280] Example 7

[0281] The blocking performance of low-frequency drift components was improved by applying a supercapacitor containing an ionic liquid electrolyte to the drift compensation circuit of Example 4.

[0282] In this embodiment, a high-pass filter including a supercapacitor was added to the drift compensation circuit. The supercapacitor contained an ionic liquid electrolyte.

[0283] 1-ethyl-3-methylimidazolium bistrifluoromethanesulfonylimide was used as the ionic liquid electrolyte. The molecular formula of the corresponding ionic liquid is C8H {11}It was F6N3O4S2, the molecular weight was 391.31 g / mol, and the purity was 99%. At 25℃, the ionic conductivity was 8.8 mS / cm, the melting point was -17℃, and the thermal decomposition temperature was 400℃.

[0284] The electrodes of the supercapacitor were composed of a composite of activated carbon and a carbon-based conductive material. The specific surface area of ​​the activated carbon is 2,000 m² 2 It was / g. Carbon black was used as the carbon-based conductive material. The mass ratio of activated carbon, carbon-based conductive material, and binder was 85:10:5, and polyvinylidene fluoride was used as the binder. The electrode thickness was 100 micrometers, and the electrode area was 10 cm². 2 It was. The entire house was made of aluminum.

[0285] The capacitance of the supercapacitor was 10F, the equivalent series resistance was 50 milliohms, and the rated voltage was 2.5V.

[0286] The high-pass filter was constructed with a 50-ohm resistor and a 10F supercapacitor. The time constant of the high-pass filter was 500 seconds, and the cutoff frequency was 0.0003 Hz.

[0287] The capacitance variation of the supercapacitor was within ±5% in the temperature range of -20℃ to 60℃. Zero-point drift decreased to 0.02% / hour or less.

[0288] In this embodiment, by applying an ionic liquid supercapacitor, continuous measurement for more than 24 hours was possible without zero point adjustment, and stable drift compensation was performed in a wide temperature environment.

[0289] Example 8

[0290] Microphonic noise caused by mechanical vibration of the substrate was canceled by adding an active vibration cancellation unit to the interference cancellation computing device 200 of Example 1.

[0291] In this embodiment, an active vibration cancellation unit was laminated onto a substrate on which an interference cancellation operation circuit 6 was mounted. The active vibration cancellation unit included an acceleration sensor, a piezoelectric actuator, and a feedback control circuit.

[0292] A MEMS accelerometer was used as the accelerometer. The sensitivity of the MEMS accelerometer was 300 mV / g, the bandwidth was DC to 1.6 kHz, and the measurement range was ±3 g. The noise density was 50 microg / √Hz, and the external dimensions were 4 mm × 4 mm × 1.5 mm.

[0293] The piezoelectric actuator contained a lead magnesium niobate-lead titanate single crystal. The PMN-PT single crystal was grown by the Bridgman method and cut in the 001 direction. The compositional ratio of the PMN-PT single crystal was 0.67 PMN-0.33 PT. The piezoelectric constant d 33 was 2,000 pC / N, and the electromechanical coupling coefficient k 33 was 0.92, and the dielectric constant ε 33 The value was 5,000. The thickness of the PMN-PT single crystal was 0.5 mm, and the area was 20 mm × 20 mm. The PMN-PT single crystal was attached to a substrate with epoxy adhesive, and the curing conditions were 65°C for 2 hours.

[0294] The feedback control circuit included an analog PID controller. The proportional gain K of the analog PID controller p was 10, and the integration time constant T i was 0.1ms, and the differential time constant T d It was 0.01ms. A high-voltage amplifier was connected to the feedback control circuit, and the output voltage range of the high-voltage amplifier was 0V to 150V, and the bandwidth was 10kHz.

[0295] In the absence of an active vibration cancellation unit, the measurement error due to microphonic noise under flow conditions was ±0.5%. When an active vibration cancellation unit was applied, the vibration damping in the DC to 500Hz band was 20dB, and the measurement error was reduced to ±0.05% or less.

[0296] In this embodiment, by applying a PMN-PT piezoelectric single crystal active vibration cancellation unit, the signal-to-noise ratio was improved by 15dB at high-frequency vibrations of 100Hz or higher, and precise interference cancellation calculations were possible even in water tank tests under flow conditions.

[0297] Example 9

[0298] An interference removal calculation system was constructed by integrating the configurations of Examples 1 to 8.

[0299] In this embodiment, the interference cancellation operation system was configured with a signal input module, a multiplication operation module, a summation operation module, and an amplification operation module. The signal input module received output signal 1 from the 6-component force meter Wheatstone bridge circuit of Example 1.

[0300] The multiplication operation module included a resistance network including the tantalum nitride thin film resistor of Example 5 and a buffer amplifier. The temperature compensation module of Example 2 was connected to the multiplication operation module. The temperature compensation module included a Pt100 thermistor and a 4th quadrant analog multiplier.

[0301] The summation operation module included an operational amplifier adder circuit. The nonlinear correction module of Example 3 was connected to the output of the summation operation module. The nonlinear correction module included a diode function generator composed of eight diodes.

[0302] The amplification operation module included a low-noise operational amplifier. The drift compensation module of Examples 4 and 7 was connected to the output of the amplification operation module. The drift compensation module included a high-pass filter comprising a chopper stabilized amplifier and an ionic liquid supercapacitor.

[0303] The multiplication operation module, the summation operation module, and the amplification operation module were housed in the nanocrystalline soft magnetic alloy magnetic shielding housing of Example 6. The PMN-PT piezoelectric single crystal active vibration cancellation unit of Example 8 was laminated on the substrate on which each module was mounted.

[0304] The interference cancellation calculation system was applied to the 6-component force meter for the slender underwater vehicle model of Example 1. Before the application of the interference cancellation calculation system, the interference in the Fx channel was -25.0%, the interference in the Fy channel was 10.8%, and the interference in the Fz channel was -17.0%.

[0305] After applying the interference cancellation calculation system, interference between all components was controlled to less than 1%. The variation in interference coefficients was within ±0.5% in the water temperature range of 5°C to 30°C. During 6 months of continuous underwater operation, the variation in interference coefficients was within ±0.3%. Continuous measurement for more than 24 hours was possible without zero point adjustment. The signal-to-noise ratio improved by 20 dB in an electromagnetic noise environment. Under flow conditions, the measurement error caused by microphonic noise was ±0.05% or less.

[0306] In this embodiment, long-term underwater operational stability, adaptability to a wide temperature range, electromagnetic immunity, and dynamic environmental precision were simultaneously secured through the integrated configuration of the interference cancellation computation system, and all measurement performance requirements for slender underwater vehicle model testing were satisfied.

[0307] Although embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be obvious to those skilled in the art that various modifications and variations are possible within the scope of the technical concept of the present invention as described in the claims.

Claims

Claim 1 An interference cancellation operation device for eliminating interference between force components of a multi-component force system that simultaneously measures multiple force components acting on an object, comprising: an input unit connected to a Wheatstone bridge circuit of the multi-component force system and receiving an output signal including a signal component corresponding to the force component to be measured and an interference signal component caused by another force component; a multiplication operation element connected to the input unit and receiving the output signal from the input unit, comprising a resistance network configured to have a distribution ratio corresponding to an interference coefficient obtained in a calibration test, and generating and outputting an interference correction signal multiplied by the interference coefficient when the output signal passes through the resistance network; an addition operation element connected to the input unit and the multiplication operation element, receiving the output signal from the input unit and receiving the interference correction signal from the multiplication operation element, comprising an adder circuit which is an inverting adder including a first operational amplifier, and subtracting the interference correction signal from the output signal to output an interference cancellation signal; and a diode function generator disposed downstream of the addition operation element and composed of a plurality of diodes and a plurality of resistors, wherein a second-order or higher-order interference component remaining in the interference cancellation signal A non-linear correction circuit for correction; a voltage amplifier including a second operational amplifier separate from the first operational amplifier, which is connected to the summing operation element through the non-linear correction circuit, and an amplification operation element that compensates for signal attenuation and voltage drop in the circuit occurring during the operation process in the multiplication operation element and the summing operation element to output an interference-separated output signal at a rated output level; and a drift compensation circuit disposed downstream of the amplification operation element, which includes a chopper stabilization amplifier or an auto-zero amplifier, and removes DC offset and low-frequency drift components occurring during long-term measurement;An interference cancellation operation device comprising: a multiplication operation element further comprising a temperature compensation circuit, wherein the temperature compensation circuit comprises a temperature detection unit including a thermistor and an analog multiplier connected to the temperature detection unit to compensate for changes in the characteristics of the resistance network according to temperature changes in real time, wherein the resistance network of the multiplication operation element comprises a ceramic substrate and a tantalum nitride thin film resistor formed on the ceramic substrate, wherein the multiplication operation element, the summing operation element, and the amplification operation element are sequentially connected in this order to form an interference cancellation operation circuit, and wherein the interference cancellation operation circuit performs operations in an analog signal state without quantifying the output signal. Claim 2 An interference removal computing device according to claim 1, wherein the resistance of the tantalum nitride thin film is adjusted to a resistance value corresponding to the interference coefficient by laser trimming, and the laser trimming is performed by an Nd:YAG laser. Claim 3 An interference removal operation device according to claim 1, wherein the inverting adder of the summing operation element further comprises an input resistor and a feedback resistor connected to the first operation amplifier. Claim 4 An interference cancellation operation device according to claim 1, wherein the voltage amplifier of the amplification operation element further comprises a gain setting resistor connected to the second operation amplifier. Claim 5 An interference removal calculation device according to claim 1, wherein the interference removal calculation device comprises: a first interference removal calculation circuit; and a second interference removal calculation circuit connected to the output of the first interference removal calculation circuit. Claim 6 The interference cancellation computing device according to claim 1, wherein the interference cancellation computing device is disposed in the internal space of the multi-component force meter or disposed between the output terminal of the multi-component force meter and a data logger. Claim 7 An interference cancellation operation system for eliminating interference between force components of a multi-component force system that simultaneously measures multiple force components acting on an object, comprising: a signal input module that receives an output signal including a signal component corresponding to the force component to be measured and an interference signal component caused by another force component from a Wheatstone bridge circuit of the multi-component force system; a multiplication operation module connected to the signal input module and including a resistance network and a buffer amplifier connected to the resistance network, and generating an interference correction signal by applying an interference coefficient to the output signal; a summation operation module connected to the signal input module and the multiplication operation module, and generating an interference cancellation signal by summing the output signal and the interference correction signal; a non-linear correction module connected to the downstream end of the summation operation module and including a diode function generator; an amplification operation module connected to the summation operation module and amplifying the interference cancellation signal to generate an interference separation output signal; and a drift compensation module connected to the downstream end of the amplification operation module and including a chopper stabilization amplifier or an auto-zero amplifier. An interference cancellation operation system comprising: a temperature compensation module connected to the multiplication operation module and including a thermistor and an analog multiplier connected to the thermistor; wherein the resistance network of the multiplication operation module includes a tantalum nitride thin film resistor formed on a ceramic substrate, and the multiplication operation module, the summation operation module, and the amplification operation module are connected sequentially in this order.

Images