KR20210114710A - Apparatus and Method for Linearizing Sensor Output for High Accuracy Pressure Sensor - Google Patents

Abstract

The present invention relates to a high-precision pressure sensor which can measure accurate pressure regardless of a non-linear output characteristic due to disturbance such as an external rapid temperature change by mathematically interpreting a unique output characteristic of the pressure sensor, which comprises: a detector circuit receiving a measurement value according to a change of external pressure and disturbance to be outputted at an output value having non-linearity; and a sensor output linearizing unit receiving the output value having the non-linearity of the detector circuit to extract a linearization coefficient through a function approximation algorithm using polynominal regression theory and performing analog-calculation on the extracted linearization coefficient and index to linearize a sensor value according to the linearization coefficient to output the linearized sensor value.

Description

Apparatus and Method for Linearizing Sensor Output for High Accuracy Pressure Sensor

The present invention relates to a pressure sensor, and more particularly, to an apparatus and method for linearizing the sensor output for a high-precision pressure sensor that can improve the accuracy of pressure measurement by solving the sensor's inherent non-linear output characteristics.

It is difficult to handle all the senses that humans can feel, and modern sensor parts are magnetism, displacement, vibration, acceleration, rotational speed, flow rate, flow rate, liquid component, gas component, visible light, infrared light, ultrasonic wave, microwave, and ultraviolet light. ,Radiation, X-rays, etc. are detected as electrical signals and used in industrial fields, service industries, medical fields, and academia.

In general, a detector is an element that detects, discriminates, and measures various types of physical quantities such as temperature, pressure, and humidity, and is often referred to as a sensor.

By converting the signal detected by the sensor into an electrical signal, it can be amplified, accumulated, manipulated, etc. in the form of a signal that can be recognized by a microcontroller or computer, and can be utilized according to the application.

Among these sensors, the pressure sensor is a device that measures a physical quantity indicating the magnitude of the interaction force between two objects, and is widely used to measure the magnitude of force transmission and the direction of the force.

The fields of use are applied to general industrial products and industrial facilities such as medical, automobile, aviation, industrial measurement, home appliance, and environmental control fields. etc. will be used.

In the current mechanical sensing method, semiconductor device manufacturing technology and Micro Electro Mechanical System (MEMS) technology are used for miniaturization of the sensor device.

Such a pressure sensor is installed on a flow path or a valve side through which a fluid passes in ships, automobiles, chemical facilities, semiconductor manufacturing facilities, and the like, and is mainly used to measure the pressure of the fluid.

For example, the cylinder pressure of a ship or automobile engine, the pressure of a fuel injection system, the pressure of hydrogen gas or air in a fuel cell vehicle, the exhaust gas pressure in a silencer, and other general industrial pressure gauges with high precision in a wide pressure range from low to high pressure. Used to measure the road.

In the case of a specific field in the use of such a pressure sensor, there is a problem in that an error occurs due to the influence of disturbance.

For example, in the case of an ultra-high pressure (up to 1,000 bar) pressure sensor for measuring the pressure of a hydrogen tank in a hydrogen fuel cell vehicle, when charging and discharging hydrogen, the measurement unit is sensitive to disturbances such as an instantaneous sudden temperature change (-40 degrees below zero to 90 degrees above zero). There is a problem in that the non-linear output characteristics are increased by this, and the error is greatly generated.

Therefore, there is a demand for the development of a sensor data processing technology of a new technology capable of increasing the data reliability of the high-precision pressure sensor.

Republic of Korea Patent Registration No. 10-2025253 Republic of Korea Patent Publication No. 10-2017-0033246 Republic of Korea Patent Publication No. 10-2019-0036970

The present invention is to solve the problem of the pressure sensor of the prior art, and provides an apparatus and method for linearizing the sensor output for a high-precision pressure sensor that can improve the accuracy of pressure measurement by solving the sensor's inherent non-linear output characteristic. Its purpose is to provide

The present invention provides an apparatus and method for linearizing the sensor output for a high-precision pressure sensor that increases the precision of the sensor and enables high-speed signal processing by linearizing the non-linear output value of the change in the sensor probe impedance according to the measured pressure. There is a purpose.

The present invention enables the utilization of a non-linear section by using a device that linearizes a non-linear output value of a change in sensor probe impedance according to the measured pressure, thereby expanding the measurement range and improving the robustness to disturbance. An object of the present invention is to provide an apparatus and method for linearizing a sensor output for a high-precision pressure sensor.

An object of the present invention is to provide an apparatus and method for linearizing a sensor output for a high-precision pressure sensor that is composed of an analog circuit and performs linearization according to a set linearization coefficient to enable high-speed signal processing.

The present invention is a high-precision pressure sensor including a linearization algorithm that extracts a linearization coefficient required for linearization from a de-modulator output value (raw data) having non-linearity and can easily implement it on an analog circuit. An object of the present invention is to provide an apparatus and method for sensor output linearization for

The present invention is a high-precision pressure sensor that improves reliability of data by extracting linearization coefficients by applying a function approximation algorithm applying a statistical technique, polynominal regression theory, using output data according to changes in external pressure and disturbance. An object of the present invention is to provide an apparatus and method for sensor output linearization for

Other objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned will be clearly understood by those skilled in the art from the following description.

An apparatus for linearizing sensor output for a high-precision pressure sensor according to the present invention for achieving the above object is a detection circuit that receives a measurement value through a sensor probe and outputs it as an output value having non-linearity; Non-linearity of the detection circuit Linearization of sensor output that receives an output value with It is characterized in that it includes;

A method for linearizing a sensor output for a high-precision pressure sensor according to the present invention for achieving another object is a method for a high-precision pressure sensor, comprising the steps of receiving a demodulator output value (raw data) having non-linearity as an input ; Extracting the linearization coefficient from the raw data of the demodulator having nonlinearity to a function approximation algorithm applying the polynominal regression theory; receiving the exponential output value from the exponential circuit, The value of the resistance element in the circuit is determined according to the linearization coefficient determined by the DSP (Digital Signal Processor) by performing analog operation on the extracted linearization coefficient and exponent, and linearization is performed by analog numerical operation; if it is a positive number, the sigma circuit (Σ) and outputting a linearized data value by applying an addition circuit in , and applying a subtraction circuit in the sigma circuit Σ when the number is negative.

The apparatus and method for linearizing sensor output for a high-precision pressure sensor according to the present invention as described above have the following effects.

First, it is possible to increase the precision of the sensor by linearizing a nonlinear output value such as a change in the impedance of the sensor probe according to the measured pressure.

Second, the use of a device that linearizes non-linear output values such as sensor probe impedance change according to the measured pressure enables the use of a non-linear section to expand the measurement pressure range and increase the robustness to measurement disturbances. can be secured

Third, high-speed signal processing is possible by extracting the linearization coefficient required for linearization from the raw data of the de-modulator with non-linearity and including a linearization algorithm that can be easily implemented on an analog circuit. do.

1 is an overall configuration diagram of a sensor data processing system for a high-precision pressure sensor according to the present invention;
2 is a block diagram of an apparatus for linearizing sensor output for a high-precision pressure sensor according to the present invention;
3 is a detailed configuration diagram of an apparatus for linearizing sensor output for a high-precision pressure sensor according to the present invention;
4 is a detailed configuration diagram of an output linearization unit;
5 is a flowchart illustrating a method for linearizing sensor output for a high-precision pressure sensor according to the present invention.

Hereinafter, a preferred embodiment of an apparatus and method for linearizing a sensor output for a high-precision pressure sensor according to the present invention will be described in detail as follows.

Characteristics and advantages of the apparatus and method for linearizing sensor output for a high-precision pressure sensor according to the present invention will become apparent from the detailed description of each embodiment below.

1 is an overall configuration diagram of a sensor data processing system for a high-precision pressure sensor according to the present invention.

The apparatus and method for linearizing sensor output for a high-precision pressure sensor according to the present invention are non-linear by using an apparatus for linearizing the non-linear output value of the sensor probe impedance change according to the displacement measured by the high-precision pressure sensor. By enabling the use of sections, the performance of expanding the measurement range and minimizing the diameter of the measurement target is improved.

To this end, the present invention is composed of an analog circuit and performs linearization according to a set linearization coefficient to configure a device to enable high-speed signal processing, and a de-modulator output value (raw) having non-linearity data) extracts a linearization coefficient required for linearization and includes a linearization algorithm that can be easily implemented on an analog circuit.

In particular, the present invention includes a configuration for extracting linearization coefficients by applying a function approximation algorithm applying a statistical technique, a polynomial regression theory, using output value data for each change in the distance between a measurement object and a sensor probe.

As shown in FIG. 1, the sensor data processing system for a high-precision pressure sensor according to the present invention compares pre-stored information (electrical impedance data table of the probe and extension cable) with the electrical impedance measurement value of the currently connected probe and extension cable. Extracting the linearization coefficient required for linearization from the automatic setting unit 100 providing information necessary for setting the setting value and the output value of the demodulator having non-linearity (raw data) and implementing it on the analog circuit The linearization unit 200 linearizes the nonlinear output value of the sensor probe impedance change according to the measured displacement, and the raw data measured from the sensor is transmitted to the upper system without data loss through data compression technology. and a data compression and network transmission support unit 300 that supports data compression and network transmission by allowing the same prediction result value to be provided with minimum data by determining in advance the validity/invalidation of the sensed data.

The configuration of the device for linearizing the sensor output for the high-precision pressure sensor according to the present invention having the above configuration will be described as follows.

2 is a block diagram of an apparatus for linearizing sensor output for a high-precision pressure sensor according to the present invention, and FIG. 3 is a detailed block diagram of an apparatus for linearizing a sensor output for a high-precision pressure sensor according to the present invention.

As shown in FIG. 2, the apparatus for linearizing sensor output for a high-precision pressure sensor according to the present invention receives a measurement value through the sensor probe 21 and outputs it as raw data having nonlinearity ( The linearization coefficient ( The value of the resistance element in the circuit is determined according to the linearization coefficient determined by the DSP (Digital Signal Processor) by analog operation of the extracted linearization coefficient and exponent, and the value of the resistance element is linearized by analog numerical operation to autotuner. It includes a sensor output linearization unit 24 that outputs to (Auto Tuner) 24 .

Here, as shown in FIG. 3 , the sensor output linearization unit 24 includes an input unit (X) 30 that receives raw data from a de-modulator having nonlinearity, and an output having nonlinearity. It receives raw data and extracts the linearization coefficient with a function approximation algorithm that applies the polynominal regression theory, and performs analog operation on the extracted linearization coefficient and exponent according to the linearization coefficient. The linearization unit 31 for performing linearization, and an output unit Y for outputting a linearized data value by applying an addition circuit in the Sigma circuit Σ when the number is positive, and applying a subtraction circuit in the Sigma circuit Σ when the number is negative. ) (32).

Here, the output value (Y) with respect to the input value (X) may be a function approximation as in Equation (1).

인 정규(Gaussian)분포를 갖는다고 가정한다.For function approximation, the error has a mean of '0' and a variance of

It is assumed to have a Gaussian distribution.

The linearization coefficient "Bi" extraction value (maximum likelihood estimates) can be derived by minimizing the chi-square value as shown in Equation (3).

The extracted linearization coefficients are expressed in matrix form as follows.

At this time, the standard deviation, which is a performance indicator, is as follows, and it can be confirmed that the reliability improves as the number of raw-data samples (n) used for function approximation increases and the function approximation order (k) increases.

The detailed configuration of the linearization unit in the apparatus for linearizing the sensor output for the high-precision pressure sensor according to the present invention is as follows.

4 is a detailed configuration diagram of an output linearization unit.

The output linearization part is composed of a kind of analog calculator using analog active and passive elements, and the value of the resistance element in the circuit is determined according to the linearization coefficient determined by the DSP (Digital Signal Processor), and it is linearized by analog numerical operation. .

The reason why analog circuits are used instead of digital signal processing is for fast signal processing.

As shown in FIG. 4 , the output linearization unit includes a de-modulator circuit having non-linearity composed of a plurality of multiplication circuits (OP-Amp application circuits) and a de-modulator output unit (raw data) input unit 41, a plurality of Polynomial regression is composed of an exponent circuit unit 42 that is composed of an exponent circuit (OP-Amp application circuit) and outputs an exponent (Xk), and a number of digital variable resistors controlled by the DSP in an amount proportional to the linearization coefficient. ) The linearization coefficient extraction unit 43 for extracting the linearization coefficient by a function approximation algorithm applying the theory, and the linearization coefficient determined by the DSP (Digital Signal Processor) by analog operation of the extracted linearization coefficient and the exponent ), a linearization unit that determines the value of the resistance element in the circuit and linearizes it by analog numerical operation, and a sigma circuit (Σ) that applies an addition circuit if it is a positive number and a subtraction circuit to output a linearized data value if it is a negative number. (44) and an output section (45) for outputting the data value of the sigma circuit (Σ) (44).

A control operation for sensor output linearization in the device for sensor output linearization for a high-precision pressure sensor according to the present invention having such a configuration will be described as follows.

5 is a flowchart illustrating a method for linearizing a sensor output for a high-precision pressure sensor according to the present invention.

First, a de-modulator output value (raw data) having non-linearity is input (S501).

Then, the exponential output value is received from the exponential circuit (S502), and the polynomial regression theory is applied from the de-modulator output value (raw data) with nonlinearity to the function approximation algorithm. Linearization Coefficient is extracted. (S503)

Next, the extracted linearization coefficient and exponent are subjected to analog operation, and the value of the resistance element in the circuit is determined according to the linearization coefficient determined by the DSP (Digital Signal Processor), and is linearized by analog numerical operation (S504).

In case of a positive number, an addition circuit is applied in the Sigma circuit (Σ), and when it is a negative number, a subtraction circuit is applied in the Sigma circuit (Σ) to output a linearized data value (S505).

The apparatus and method for linearizing sensor output for a high-precision pressure sensor according to the present invention described above linearize the non-linear output value of the change in the sensor probe impedance according to the measured displacement to increase the precision of the sensor and enable high-speed signal processing made to do it

As described above, the present invention enables the utilization of a non-linear section by using a device that linearizes a non-linear output value of a change in the sensor probe impedance according to the measured displacement, thereby expanding the measurement range and minimizing the diameter of the measurement target, etc. can improve the performance of

It will be understood that the present invention is implemented in a modified form without departing from the essential characteristics of the present invention as described above.

Therefore, the specified embodiments are to be considered in an illustrative rather than a restrictive sense, the scope of the present invention is indicated in the claims rather than in the foregoing description, and all differences within the scope equivalent thereto are included in the present invention. will have to be interpreted.

100. Automatic setting unit
200. Linearization
300. Data Compression and Network Transmission Support Department

Claims (7)

a detection circuit that receives the measured value through the sensor probe and outputs it as an output value having non-linearity;
The output value having the non-linearity of the detection circuit is input, the linearization coefficient is extracted with a function approximation algorithm applying the polynominal regression theory, and the sensor value is linearized according to the linearization coefficient by analog operation of the extracted linearization coefficient and the exponent. and a sensor output linearization unit for outputting a sensor output linearization device for a high-precision pressure sensor, comprising: a. According to claim 1, wherein the sensor output linearization unit,
an input unit (X) for receiving an output value of a detection circuit having non-linearity;
An output linearizer that receives an output value having nonlinearity as an input, extracts a linearization coefficient using a function approximation algorithm applying polynomial regression theory, and performs an analog operation on the extracted linearization coefficient and exponent to perform linearization according to the linearization coefficient;
High-precision pressure comprising an output unit (Y) for outputting a linearized data value by applying an addition circuit in the sigma circuit (Σ) in the case of a positive number, and by applying a subtraction circuit in the sigma circuit (Σ) in the case of a negative number Device for sensor output linearization for sensors. The method according to claim 2, wherein the output value (Y) of the output unit with respect to the input value (X) of the input unit is:

A device for sensor output linearization for a high-precision pressure sensor, characterized in that the function is approximated as 4. The method according to claim 3, wherein for function approximation, the error has a mean of '0' and a variance

Assuming it has a Gaussian distribution,

A device for sensor output linearization for a high-precision pressure sensor, characterized in that it is defined as According to claim 4, Linearization coefficient (Linearization Coefficient) extraction value (maximum likelihood estimates),

is derived by minimizing the chi-square value,
If the extracted linearization coefficient is displayed in a matrix form,

A device for sensor output linearization for a high-precision pressure sensor, characterized in that The method of claim 2, wherein the output linearization unit,
an exponent circuit unit for receiving raw data of a de-modulator having non-linearity through the input unit and outputting an exponent (X);
A linearization coefficient extractor that extracts a linearization coefficient with a function approximation algorithm that is composed of a number of digital variable resistors that the DSP controls in an amount proportional to the linearization coefficient, and applies the polynominal regression theory;
A linearization unit that performs analog operation on the linearization coefficient and exponent extracted from the linearization coefficient extractor, determines the value of the resistance element in the circuit according to the linearization coefficient determined by the DSP (Digital Signal Processor), and linearizes it by analog numerical operation;
An apparatus for linearizing sensor output for a high-precision pressure sensor, comprising a sigma circuit (Σ) for outputting a linearized data value by applying an addition circuit when the number is positive, and applying a subtraction circuit when the number is negative. receiving a de-modulator output value (raw data) having non-linearity as an input;
extracting a linearization coefficient from a de-modulator output value (raw data) having nonlinearity with a function approximation algorithm applying a polynominal regression theory;
The step of receiving the exponent output value from the exponent circuit, performing analog operation on the extracted linearization coefficient and exponent, determining the value of the resistance element in the circuit according to the linearization coefficient determined by the DSP (Digital Signal Processor), and linearizing it by analog numerical operation ;
For a high-precision pressure sensor comprising: applying an addition circuit in the sigma circuit (Σ) when a positive number, and outputting a linearized data value by applying a subtraction circuit in the sigma circuit (Σ) when it is a negative number Method for linearizing sensor output.

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