Oil mass measuring device and aircraft

Abstract

The utility model discloses an oil mass measuring device and an aircraft, and relates to the technical field of oil mass measurement. The oil quantity measuring device comprises a sensor capacitor, a frequency signal circuit and a main control chip. The sensor capacitor is located in an oil tank and composed of an inner electrode tube and an outer electrode tube, the frequency signal circuit comprises a first capacitor, a first resistor and a first operational amplifier, the sensor capacitor and the first capacitor are connected in parallel to form a second capacitor, and the second capacitor and the first resistor are connected in series to form an oscillating circuit. The oscillating circuit is connected with the first operational amplifier. The oscillating circuit is used for converting a sensor capacitance value to obtain an oscillating signal. The first operational amplifier is used for amplifying the oscillating signal to obtain a frequency signal. And the main control chip is connected with the frequency signal circuit and is used for searching the oil mass height corresponding to the frequency signal in a preset mapping relation as an oil mass measurement value. The chip is small in calculation amount, and the circuit structure is simple, stable and reliable.

Description

Technical Field

[0001] The utility model relates to the technical field of oil quantity measurement, in particular to an oil quantity measuring device and an aircraft. Background Art

[0002] Accurately measuring the fuel level of an aircraft is of great significance for ensuring flight safety, improving economic benefits, maintaining equipment reliability and performance, and improving aviation safety. The fuel level measurement device in the related technology usually includes a single-chip microcomputer, an inverter, a simulator, an analog-to-digital converter, etc., which uses a large number of electronic components, has a large amount of calculation, and has a complex circuit structure and poor reliability. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the embodiment of the present application provides a fuel quantity measuring device and an aircraft, which can effectively reduce the amount of calculation, simplify the circuit structure and improve reliability.

[0004] In a first aspect, an embodiment of the present application provides an oil level measuring device, comprising:

[0005] A sensor capacitor is located in the oil tank and includes an inner electrode tube and an outer electrode tube, wherein the sensor capacitor is formed between the inner electrode tube and the outer electrode tube;

[0006] A frequency signal circuit, comprising a first capacitor, a first resistor and a first operational amplifier, wherein the sensor capacitor is connected in parallel with the first capacitor to form a second capacitor, the second capacitor is connected in series with the first resistor to form an oscillation circuit, and the oscillation circuit is connected to the first operational amplifier; the oscillation circuit is used to convert the sensor capacitance value of the sensor capacitor to obtain an oscillation signal, and the first operational amplifier is used to amplify the oscillation signal to obtain a frequency signal;

[0007] A main control chip is connected to the frequency signal circuit, and the main control chip is used to search for the oil level height corresponding to the frequency signal in a preset mapping relationship as the oil level measurement value.

[0008] In some embodiments of the present application, a transistor is further included, wherein the base of the transistor is connected to the output end of the frequency signal circuit, the emitter of the transistor is connected to the input end of the main control chip, and the base of the transistor is grounded.

[0009] In some embodiments of the present application, a voltage conversion circuit is further included, wherein the voltage conversion circuit includes a power supply, a second resistor, a third resistor, and a second operational amplifier;

[0010] One end of the second resistor is connected to the power supply, the other end of the second resistor is connected to the third resistor, the input end of the second operational amplifier is connected between the second resistor and the third resistor, the other end of the third resistor is grounded, and the output end of the second operational amplifier is connected to the frequency signal circuit.

[0011] In some embodiments of the present application, the resistance value of the second resistor is the same as the resistance value of the third resistor.

[0012] In some embodiments of the present application, the output end of the second operational amplifier is connected to the inverting input end of the first operational amplifier, and the output end of the second operational amplifier is also connected to the oscillation circuit, and the oscillation circuit is connected to the non-inverting input end of the first operational amplifier.

[0013] In some embodiments of the present application, the oscillation signal is a triangular wave, and the frequency signal is a square wave; the first operational amplifier is used to amplify and adjust the waveform of the triangular wave to obtain the square wave.

[0014] In some embodiments of the present application, the corresponding relationship between the frequency signal and the oil level is stored in the preset mapping relationship, and the oil level is inversely proportional to the signal frequency of the frequency signal in the mapping relationship, and the mapping relationship is: f=1 / (A+KH);

[0015] Wherein, H is the oil level height, f is the signal frequency of the frequency signal, A is the first frequency constant, and K is the second frequency constant.

[0016] In some embodiments of the present application, the first frequency constant satisfies: A=2πR1×[(2πε0)×L / (lnR / r)+C1];

[0017] Among them, π is pi, R1 is the resistance value of the first resistor, C1 is the capacitance value of the first capacitor, ε0 is the dielectric constant of air, L is the height of the sensor capacitor, R is the radius of the outer electrode tube, and r is the radius of the inner electrode tube.

[0018] In some embodiments of the present application, the second frequency constant satisfies: K=2πR1×[(2πεx-2πε0) / (lnR / r)]; wherein εx is the dielectric constant of the fuel.

[0019] In a second aspect, an embodiment of the present application further provides an aircraft, comprising the fuel quantity measuring device in the embodiment of the first aspect of the present application.

[0020] The embodiments of the present application include at least the following beneficial effects:

[0021] The embodiment of the present application provides an oil quantity measuring device and an aircraft, wherein the oil quantity measuring device includes a sensor capacitor, a frequency signal circuit and a main control chip. The sensor capacitor is located in the fuel tank, including an inner electrode tube and an outer electrode tube, and the inner electrode tube and the outer electrode tube form a sensor capacitor. The frequency signal circuit includes a first capacitor, a first resistor and a first operational amplifier, the sensor capacitor and the first capacitor are connected in parallel to form a second capacitor, the second capacitor and the first resistor are connected in series to form an oscillation circuit, and the oscillation circuit is connected to the first operational amplifier. The oscillation circuit is used to convert the sensor capacitance value of the sensor capacitor to obtain an oscillation signal, and the first operational amplifier is used to amplify the oscillation signal to obtain a frequency signal. The main control chip is connected to the frequency signal circuit, and is used to find the oil level corresponding to the frequency signal in a pre-set mapping relationship as the oil level measurement value. In this way, the sensor capacitance corresponding to different oil level heights is obtained by using the sensor capacitor, and the corresponding frequency signal is converted by the frequency signal circuit and transmitted to the main control chip, so that the oil level corresponding to different frequency signals can be found according to the preset mapping relationship as the oil level measurement value, the chip has a small amount of calculation, and the circuit structure is simple, stable and reliable.

[0022] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0024] Figure 1 This is a circuit diagram of an oil level measuring device provided by an embodiment of the present application;

[0025] Figure 2 is a circuit diagram of an oil level measuring device provided by another embodiment of the present application;

[0026] Figure 3 is a circuit diagram of an oil level measuring device provided by another embodiment of the present application;

[0027] Reference numerals:

[0028] Sensor capacitor 100, frequency signal circuit 200, main control chip 300, transistor 400, voltage conversion circuit 500, first capacitor 201, first resistor 202, first operational amplifier 203, power supply 501, second resistor 502, third resistor 503, second operational amplifier 504. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0030] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0031] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0032] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0033] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0034] Accurately measuring the fuel level of an aircraft is of great significance for ensuring flight safety, improving economic benefits, maintaining equipment reliability and performance, and improving aviation safety. In the prior art, the fuel level measurement device first controls the analog switch through a single-chip microcomputer to connect the fuel level sensor to the power supply for charging. After it is fully charged, the voltage of the fuel level sensor is inverted by an inverter. Then, the analog switch is controlled by the single-chip microcomputer to disconnect the power supply of the fuel level sensor, and it is connected to the post-stage operational amplifier to amplify a voltage signal. The analog-to-digital converter converts the voltage signal into a digital voltage signal, and the digital voltage signal is output to the external chip through the signal interface. The external chip calculates and processes the digital voltage signal to obtain the fuel level of the aircraft tank. This results in a large amount of chip calculation, more resource consumption, and the circuit uses many electronic components with high cost, and the circuit structure is complex and has poor reliability.

[0035] Based on this, the embodiments of the present application provide a fuel level measuring device and an aircraft, which can use the sensor capacitance to obtain the sensor capacitance value corresponding to different fuel level altitudes, convert the sensor capacitance value through the oscillation circuit in the frequency signal circuit, obtain the corresponding frequency signal and transmit it to the main control chip, and then find the fuel level altitude corresponding to the different frequency signals according to the preset mapping relationship as the fuel level measurement value. The chip has a small amount of calculation, and the circuit structure is simple, stable and reliable, which effectively reduces the cost.

[0036] Reference Figure 1 As shown, in some embodiments of the present application, the oil level measuring device includes a sensor capacitor 100, which is located in the oil tank and includes an inner electrode tube and an outer electrode tube, and the sensor capacitor 100 is formed between the inner electrode tube and the outer electrode tube. The inner electrode tube and the outer electrode tube can be concentric cylindrical plates made of aluminum alloy with different diameters. When the oil level height position between the two plates changes, the dielectric constant equivalent to the capacitor changes, so the sensor capacitance value of the sensor capacitor 100 will also change. Therefore, the different oil level heights in the oil tank can be directly converted into corresponding sensor capacitance values ​​through the sensor capacitor 100. It can be understood that the sensor capacitor 100 can also include a shielding tube, a shell, etc., which is not limited in this embodiment.

[0037] In some embodiments, the oil level measuring device further includes a frequency signal circuit 200, such as Figure 1 As shown, the frequency signal circuit 200 includes a first capacitor 201, a first resistor 202 and a first operational amplifier. Specifically, the sensor capacitor 100 is connected in parallel with the first capacitor 201 to form a second capacitor, the second capacitor and the first resistor 202 are connected in series to form an oscillation circuit, and the oscillation circuit is connected to the first operational amplifier to form a stable closed-loop circuit.

[0038] An oscillating circuit is a circuit that can generate a periodically changing current or voltage, and is usually used to generate signals of various frequencies. The oscillating circuit can be composed of various different components and structures, such as an inductor-capacitor oscillating circuit, a quartz crystal oscillating circuit, a resistor-capacitor oscillating circuit, etc. In this embodiment, the oscillating circuit is an oscillating circuit in which a resistor-capacitor is connected in series, which is used to convert the sensor capacitance value of the sensor capacitor 100 to obtain an oscillating signal, and then use an operational amplifier to amplify the oscillating signal to obtain a frequency signal, which is not limited in this embodiment.

[0039] In some embodiments of the present application, the oscillation signal is a triangular wave, the frequency signal is a square wave, and the first operational amplifier is used to amplify and adjust the waveform of the triangular wave to obtain a corresponding square wave. It can be understood that the signal frequency of the triangular wave is the same as the signal frequency of the square wave, which is determined by the resistance and capacitance in the resistor-capacitor oscillation circuit. Specifically, the signal frequency and the resistance and capacitance satisfy the relationship f=1 / (2πRC), where f is the signal frequency, π is the circumference of the circle, R is the resistance value, and C is the capacitance value. Thus, the signal frequency in the resistor-capacitor oscillation circuit can be changed by changing the value of the resistor and / or capacitor.

[0040] It can be understood that the second capacitor obtained by connecting the first capacitor 201 and the sensor capacitor 100 in parallel can adjust the size of the second capacitor and thus adjust the signal frequency of the oscillation signal by only changing the size of the first capacitor 201 according to actual needs. For example, when the first capacitor 201 increases, the second capacitor increases and the oscillation frequency decreases; when the first capacitor 201 decreases, the second capacitor decreases and the oscillation frequency increases. By adjusting the frequency range of the circuit, it can adapt to different chip requirements, effectively improving the applicability of the circuit.

[0041] In some embodiments, the frequency signal circuit 200 can be connected to resistors or voltages of different resistance values ​​according to actual needs. Figure 1 As shown, the oscillation circuit is connected to the reference voltage VCC through a resistor and is connected to the non-inverting input terminal ("+") of the first operational amplifier, the inverting input terminal ("-") of the first operational amplifier is connected to the reference voltage VCC through a resistor, and the output terminal of the first operational amplifier is connected to the main control chip 300 through a resistor. It can be understood that those skilled in the art can set it according to actual needs, and this embodiment does not limit this.

[0042] In some embodiments, the main control chip 300 is connected to the frequency signal circuit 200, specifically to the output end of the first operational amplifier in the frequency signal circuit 200, for receiving the frequency signal and searching the oil level height corresponding to the frequency signal in a preset mapping relationship as the oil level measurement value. It is understandable that the main control chip 300 can be a commonly used single-chip microcomputer or programmable logic device, and this embodiment does not limit this.

[0043] Reference Figure 2As shown, in some embodiments of the present application, the oil level measuring device further includes a transistor 400. Specifically, the base of the transistor 400 is connected to the output end of the frequency signal circuit 200, the emitter of the transistor 400 is connected to the input end of the main control chip 300, and the base of the transistor 400 is grounded. Thus, the isolation of the frequency signal circuit 200 and the external main control chip 300 is achieved through the transistor 400, the anti-interference ability of the circuit structure is enhanced, and the transistor 400 can be used to adjust the amplitude of the frequency signal output by the frequency signal circuit 200, for example, to amplify or reduce the amplitude of the frequency signal, so as to adapt to the environment of the external chip and improve the applicability of the circuit.

[0044] Reference Figure 3 As shown, in some embodiments of the present application, the oil quantity measuring device further includes a voltage conversion circuit 500, and the voltage conversion circuit 500 includes a power supply 501, a second resistor 502, a third resistor 503, and a second operational amplifier 504. Specifically, one end of the second resistor 502 is connected to the power supply 501, and the other end of the second resistor 502 is connected to the third resistor 503. The input end of the second operational amplifier 504 is connected between the second resistor 502 and the third resistor 503, the other end of the third resistor 503 is grounded, and the output end of the second operational amplifier 504 is connected to the frequency signal circuit 200.

[0045] In some embodiments, the resistance of the second resistor 502 is the same as the resistance of the third resistor 503, so the second operational amplifier 504 adopts the principle of a voltage follower, which can play a buffering and isolation effect. For example, when the power supply 501 provides a 3.3V voltage, the input end of the second operational amplifier 504 corresponds to a reference voltage of 3.3V÷2=1.65V, which is transmitted to the oscillation circuit after passing through the second operational amplifier 504, thereby increasing the stable reference voltage for the oscillation circuit, and this embodiment does not limit this.

[0046] In some embodiments, the output of the second operational amplifier 504 is connected to the inverting input terminal ("-") of the first operational amplifier, and the output of the second operational amplifier 504 is also connected to the oscillating circuit, and the oscillating circuit is connected to the non-inverting input terminal ("+") of the first operational amplifier, so that the voltage conversion circuit 500 increases the stable reference voltage for the frequency signal circuit 200. The first operational amplifier is U3A, and the second operational amplifier 504 is U3B, which can be implemented by a chip containing dual operational amplifiers U3A and U3B, and this embodiment does not limit this.

[0047] In some embodiments of the present application, the correspondence between the frequency signal and the oil level is stored in the mapping relationship pre-set in the main control chip 300. Specifically, in the mapping relationship, the oil level is inversely proportional to the signal frequency of the frequency signal, and the mapping relationship can be expressed as f=1 / (A+KH), H is the oil level, f is the signal frequency of the frequency signal, A is the first frequency constant, and K is the second frequency constant.

[0048] In some embodiments, the first frequency constant satisfies: A=2πR1×[(2πε0)×L / (lnR / r)+C1], and the second frequency constant satisfies: K=2πR1×[(2πεx-2πε0) / (lnR / r)], wherein π is pi, R1 is the resistance value of the first resistor 202, C1 is the capacitance value of the first capacitor 201, ε0 is the dielectric constant of air, εx is the dielectric constant of fuel, L is the height of the sensor capacitor 100, R is the radius of the outer electrode tube, and r is the radius of the inner electrode tube.

[0049] Specifically, the sensor capacitance value C in the sensor capacitor 100 and the oil level height H satisfy:

[0050] C=(2πε0)×L / (lnR / r)+[(2πεx-2πε0) / (lnR / r)]×H;

[0051] The signal frequency f in the oscillation circuit, the capacitance value C1 of the first capacitor 201, the sensor capacitance value C of the sensor capacitor 100, and the resistance value R1 of the first resistor 202 satisfy: f=1 / [2πR1(C+C1)];

[0052] That is equivalent to f = 1 / {2πR1×[(2πε0)×L / (lnR / r)+[(2πεx-2πε0) / (lnR / r)]×H+C1])}=

[0053] 1 / {2πR1×[(2πε0)×L / (lnR / r)+C1]+2πR1×[(2πεx-2πε0) / (lnR / r)]×H}

[0054] Since π, ε0, εx, R, r, and L are all fixed values, and R1 and C1 are known data, the above relationship is equivalent to:

[0055] f=1 / (A+KH); where A=2πR1×[(2πε0)×L / (lnR / r)+C1], K=2πR1×[(2πεx-2πε0) / (lnR / r)].

[0056] In some embodiments of the present application, the fuel tank can be filled to obtain a first fuel tank height H1 and a corresponding first signal frequency f1, and the fuel tank can be zeroed to obtain a second fuel tank height H2 and a corresponding second signal frequency f2, thereby obtaining a first frequency constant A and a second frequency constant K according to the substitution relationship f=1 / (A+KH), and this embodiment does not impose any restrictions on this.

[0057] It can be seen that the main control chip 300 only needs to pre-store the first frequency constant A and the second frequency constant K, and can directly obtain the corresponding oil level height as the oil level measurement value according to the frequency signal, which effectively reduces the chip's calculation amount and saves chip resources.

[0058] The present application also provides an aircraft, including the above-mentioned fuel quantity measuring device. It is understandable that the specific implementation of the aircraft in this embodiment is basically the same as the specific implementation of the above-mentioned fuel quantity measuring device, and will not be described in detail here.

[0059] The present application provides a fuel quantity measuring device and an aircraft, wherein the fuel quantity measuring device includes a sensor capacitor, a frequency signal circuit and a main control chip. The sensor capacitor is located in the fuel tank, including an inner electrode tube and an outer electrode tube, and the sensor capacitor is formed between the inner electrode tube and the outer electrode tube. The frequency signal circuit includes a first capacitor, a first resistor and a first operational amplifier, the sensor capacitor and the first capacitor are connected in parallel to form a second capacitor, the second capacitor and the first resistor are connected in series to form an oscillation circuit, and the oscillation circuit is connected to the first operational amplifier. The oscillation circuit is used to convert the sensor capacitance value of the sensor capacitor to obtain an oscillation signal, and the first operational amplifier is used to amplify the oscillation signal to obtain a frequency signal. The main control chip is connected to the frequency signal circuit, and is used to find the fuel level corresponding to the frequency signal in a pre-set mapping relationship as the fuel level measurement value. In this way, the sensor capacitance value corresponding to different fuel level heights is obtained by using the sensor capacitor, and the corresponding frequency signal is converted by the frequency signal circuit and transmitted to the main control chip, so that the fuel level corresponding to different frequency signals can be found according to the preset mapping relationship as the fuel level measurement value, the chip has a small amount of calculation, and the circuit structure is simple, stable and reliable.

[0060] At the same time, the embodiments of the present application also include but are not limited to the following advantages:

[0061] 1) The oil quantity measuring device has a simple structure, does not require a single-chip microcomputer to control the charging and discharging of the analog switch, does not require an inverter for inversion processing and an analog-to-digital converter for switching, has no components with mechanical movements, and has high reliability.

[0062] 2) The oil quantity measuring device is made of aluminum alloy material, with a wide range of high and low temperature working range, and can work stably in a wide temperature range of -55 to 85℃.

[0063] 3) The oil quantity measuring device is sealed with aluminum alloy, which can effectively shield external electromagnetic interference and has strong anti-interference ability.

[0064] 4) The circuit structure of the oil quantity measuring device is simple, and the change of the sensor capacitance is directly converted into a frequency signal with a frequency change, which is directly transmitted to the external main control chip for calculation without any processing.

[0065] 5) The circuit of the oil quantity measuring device can be adjusted, and the specific frequency range and frequency amplitude used can be processed and adjusted according to the external main control chip environment.

[0066] 6) The circuit of the oil level measuring device effectively isolates the external main control chip processing system through the transistor, which can prevent the circuit and the external main control chip from interfering with each other.

[0067] 7) The calculation method for converting capacitance change into frequency change is simple and occupies less resources of the external main control chip.

[0068] 8) The circuit of the oil quantity measuring device has strong anti-interference ability, and the reference voltage source is processed by the voltage follower and is very stable.

[0069] 9) The oscillation circuit is directly connected to the first operational amplifier to form a closed-loop circuit, which is reliable and stable.

[0070] It should also be understood that the various implementations provided in the embodiments of the present application can be arbitrarily combined to achieve different technical effects. The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the above implementations, and technicians familiar with the art can also make various equivalent modifications or substitutions under the shared conditions that do not violate the spirit of the present application.

Claims

1. An oil quantity measuring device, characterized in that: include: A sensor capacitor is located in the oil tank and includes an inner electrode tube and an outer electrode tube, wherein the sensor capacitor is formed between the inner electrode tube and the outer electrode tube; A frequency signal circuit, comprising a first capacitor, a first resistor and a first operational amplifier, wherein the sensor capacitor is connected in parallel with the first capacitor to form a second capacitor, the second capacitor is connected in series with the first resistor to form an oscillation circuit, and the oscillation circuit is connected to the first operational amplifier; the oscillation circuit is used to convert the sensor capacitance value of the sensor capacitor to obtain an oscillation signal, and the first operational amplifier is used to amplify the oscillation signal to obtain a frequency signal; A main control chip is connected to the frequency signal circuit, and the main control chip is used to search for the oil level height corresponding to the frequency signal in a preset mapping relationship as the oil level measurement value.

2. The oil quantity measuring device according to claim 1, characterized in that: It also includes a transistor, the base of the transistor is connected to the output end of the frequency signal circuit, the emitter of the transistor is connected to the input end of the main control chip, and the base of the transistor is grounded.

3. The oil level measuring device according to claim 1, characterized in that: Also included is a voltage conversion circuit, the voltage conversion circuit including a power supply, a second resistor, a third resistor, and a second operational amplifier; One end of the second resistor is connected to the power supply, the other end of the second resistor is connected to the third resistor, the input end of the second operational amplifier is connected between the second resistor and the third resistor, the other end of the third resistor is grounded, and the output end of the second operational amplifier is connected to the frequency signal circuit.

4. The oil quantity measuring device according to claim 3, characterized in that: The resistance value of the second resistor is the same as the resistance value of the third resistor.

5. The oil level measuring device according to claim 3, characterized in that: The output end of the second operational amplifier is connected to the inverting input end of the first operational amplifier, and the output end of the second operational amplifier is also connected to the oscillation circuit, and the oscillation circuit is connected to the non-inverting input end of the first operational amplifier.

6. The oil quantity measuring device according to any one of claims 1 to 5, characterized in that: The oscillation signal is a triangular wave, and the frequency signal is a square wave; the first operational amplifier is used to amplify and adjust the waveform of the triangular wave to obtain the square wave.

7. The oil level measuring device according to claim 1, characterized in that: The predetermined mapping relationship stores a correspondence between the frequency signal and the oil level height, wherein the oil level height is inversely proportional to the signal frequency of the frequency signal, and the mapping relationship is: f=1 / (A+KH); Wherein, H is the oil level height, f is the signal frequency of the frequency signal, A is the first frequency constant, and K is the second frequency constant.

8. The oil level measuring device according to claim 7, characterized in that: The first frequency constant satisfies: A=2πR1×[(2πε0)×L / (lnR / r)+C1]; Among them, π is pi, R1 is the resistance value of the first resistor, C1 is the capacitance value of the first capacitor, ε0 is the dielectric constant of air, L is the height of the sensor capacitor, R is the radius of the outer electrode tube, and r is the radius of the inner electrode tube.

9. The oil level measuring device according to claim 8, characterized in that: The second frequency constant satisfies: K=2πR1×[(2πεx-2πε0) / (lnR / r)]; wherein εx is the dielectric constant of the fuel.

10. An aircraft, characterized in that: The oil quantity measuring device comprises the oil quantity measuring device as claimed in any one of claims 1 to 9.

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