Non-common-ground attack angle signal acquisition and calculation circuit and method

Abstract

The invention provides a non-common-ground attack angle signal acquisition and calculation circuit and method. The non-common-ground attack angle signal acquisition and calculation circuit comprises a step-down follower circuit, an isolation operational amplifier circuit, an isolation power supply circuit and an A / D acquisition and MCU calculation circuit, an isolation operational amplifier circuit is used for isolating and collecting a tap voltage signal and an excitation positive voltage signal which are output by the attack angle alarm system passing through the step-down follower circuit, and outputting the tap voltage signal and the excitation positive voltage signal to an A / D collection and MCU resolving circuit, so that collection of non-common ground attack angle signals is realized; the isolation power supply circuit provides reference voltage for the input ends of the voltage reduction follower circuit and the isolation operational amplifier circuit; the reference voltage of the output end of the isolation operational amplifier circuit is connected to the A / D acquisition and MCU resolving circuit; the A / D acquisition and MCU resolving circuit is used for resolving a local attack angle and a true attack angle; non-common-ground attack angle signals can be effectively collected under the condition that an original system is not affected.

Description

Technical Field

[0001] This invention belongs to the field of aircraft angle-of-attack signal acquisition technology, specifically relating to a non-co-located angle-of-attack signal acquisition and calculation circuit and method. Background Technology

[0002] Angle of attack (ATO) is a crucial indicator of an aircraft's flight status in aviation, representing the angle between the wing chord and the oncoming airflow. Accurately acquiring and outputting the ATO to the aircraft's display system is essential for flight safety. However, due to differences in aircraft power supply characteristics, the ATO signal from an ATO warning system is often not a standard DC signal, but rather a pulsating DC wave rectified from an AC signal.

[0003] Because the angle-of-attack alarm system can only provide a positive excitation signal, a negative excitation signal (which is not a reference ground), and a tap signal, traditional methods for acquiring angle-of-attack signals often use differential operational amplifiers (op-amps) to collect the positive excitation signal and the tap signal to complete the angle-of-attack calculation. However, the differential-mode voltage acquired by the differential op-amp cannot avoid the problem of not sharing a common ground, resulting in constant common-mode interference during the acquisition process, leading to large acquisition errors. Furthermore, due to the lack of a common ground, the common-mode voltage is uncertain, which can easily cause the acquired voltage to exceed the common-mode voltage input range, leading to op-amp saturation or even damage, ultimately resulting in invalid acquisition results. In addition, when using traditional methods, the angle-of-attack alarm system (high-voltage side) directly outputs the signal to the angle-of-attack calculation system (low-voltage side) for calculation. The angle-of-attack calculation system (low-voltage side) is at risk of high-voltage intrusion, posing a significant safety concern. Summary of the Invention

[0004] This invention proposes a non-common ground angle-of-attack signal acquisition and calculation circuit and method, which can effectively acquire non-common ground angle-of-attack signals without affecting the original system.

[0005] The first aspect of this invention proposes a non-common ground angle-of-attack signal acquisition and calculation circuit, comprising: a buck follower circuit, an isolation operational amplifier circuit, an isolation power supply circuit, and an A / D acquisition and MCU calculation circuit; The buck follower circuit includes two buck circuits and two operational amplifiers; used to reduce the excitation positive voltage signal output by the angle-of-attack alarm system according to a preset ratio. U 激励正1 With tap voltage signal U 抽头1 An operational amplifier is used to form a voltage follower circuit to output a stepped-down excitation positive voltage signal. U 激励正2 and tap voltage signal U 抽头2 ; The isolated operational amplifier circuit includes: two isolated operational amplifiers; the inputs of the two isolated operational amplifiers are respectively connected to the voltage follower circuit.U 激励正2 and U 抽头2 Connected, output terminal U 激励正3 and U 抽头3 Connected to the A / D acquisition and MCU processing circuit; Output of the isolated power supply circuit GND 3. Angle of attack warning system U 激励负1 The connected, isolated power supply circuit is used to provide a reference voltage for the input reference voltages of the buck follower circuit and the two isolated operational amplifiers. V + , V - , GND 3; The reference voltage at the output of the two isolated operational amplifiers is connected to the reference voltage inside the A / D acquisition and MCU processing circuit; The A / D acquisition and MCU calculation circuit includes an MCU chip and an A / D acquisition chip, which are used to acquire the excitation positive voltage signal and tap voltage signal output by the isolation operational amplifier circuit and input them to the MCU for calculation of local angle of attack and true angle of attack.

[0006] Optionally, the maximum input voltage of the buck follower circuit is greater than 20% of the maximum output value of the angle of attack alarm system.

[0007] Optionally, the MCU chip uses the following equation (1) to calculate the local angle of attack. The true angle of attack is calculated using the following formula (2). : Equation (1) Equation (2) In the formula, m This is the proportionality coefficient used to convert tap voltage to local angle of attack. n This is the local angle of attack compensation coefficient. m 1 represents the conversion factor between the local angle of attack and the true angle of attack. n 1 represents the true angle of attack compensation coefficient.

[0008] Optionally, the isolated power supply circuit receives external power at its input terminal. VCC and GND .

[0009] Optionally, the input impedance of the two operational amplifiers in the buck follower circuit can reach the gigahertz level.

[0010] Optionally, the resistance values ​​of the two buck circuits in the buck follower circuit are in the M ohm range.

[0011] The second aspect of the present invention provides a method for acquiring and calculating angle-of-attack signals without common ground, which is implemented using the non-common ground angle-of-attack signal acquisition and calculation circuit as described in any one of the first aspects.

[0012] A third aspect of the present invention provides a computer-readable storage medium, comprising: a memory and a processor; The memory is configured to store executable instructions; The processor is configured to implement the method as described in the second aspect when executing the executable instructions stored in the memory.

[0013] A fourth aspect of the present invention provides a computer program product comprising instructions that, when executed by a computer, implement the method described in the second aspect.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention proposes a non-grounded angle-of-attack signal acquisition and calculation circuit and method. Specifically, the method consists of a step-down follower circuit, an isolated operational amplifier circuit, an isolated power supply circuit, and an A / D acquisition and MCU calculation circuit. Addressing the issue that the angle-of-attack signal output is a pulsating DC wave signal without a reference ground, the method acquires and calculates the angle-of-attack signal through isolated acquisition and comparative calculation, achieving non-grounded angle-of-attack signal acquisition and calculation. This method fundamentally solves the common-mode interference problem inherent in differential operational amplifiers, achieving higher-precision acquisition. Furthermore, the isolation acquisition between the high-voltage and low-voltage sides ensures the safety of the angle-of-attack acquisition system. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the principle of a non-common ground angle-of-attack signal acquisition and calculation circuit according to the present invention; Figure 2 This is a flowchart illustrating a non-co-located angle-of-attack signal acquisition and calculation method according to the present invention. Figure 3 This is a data comparison diagram of a non-common ground angle-of-attack signal acquisition and calculation circuit and method according to the present invention; Figure 4 This table compares the theoretical local angle of attack and true angle of attack with the measured local angle of attack and true angle of attack of this system, as well as the local angle of attack and true angle of attack calculated by a general voltage acquisition circuit. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be described in more detail below with reference to the accompanying drawings.

[0018] In the accompanying drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of the present invention.

[0019] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0021] This invention provides a non-common ground angle-of-attack signal acquisition and calculation circuit and method, including: a buck follower circuit, an isolation operational amplifier circuit, an isolation power supply circuit, and an A / D acquisition and MCU calculation circuit; Buck Follower Circuit: This circuit consists of a buck resistor and an operational amplifier. It reduces the excitation positive voltage signal and tap voltage signal output by the angle of attack alarm system by a certain ratio, and uses the operational amplifier to form a voltage follower circuit to output the bucked excitation positive voltage signal and tap voltage signal. Isolation operational amplifier circuit: This circuit contains two isolation operational amplifiers, which are used to isolate the tap voltage signal and the excitation positive voltage signal output by the angle of attack alarm system and output them to the A / D acquisition and MCU calculation circuit to realize the acquisition of non-common ground angle of attack signals; Isolation power supply circuit: used to provide reference voltage for isolation operational amplifier circuits and buck follower circuits; A / D acquisition and MCU calculation circuit: This circuit mainly consists of an MCU chip and an A / D acquisition chip. It is used to acquire the excitation positive voltage signal and tap voltage signal output by the isolation operational amplifier circuit and input them to the MCU for calculation of local angle of attack and true angle of attack. The main technical solutions of this circuit include: The output voltage signals of the angle-of-attack alarm system are respectively U 激励正1 , U 激励负1 and U 抽头1 Signal, in which U 激励正1The input of a step-down circuit is connected to the input of another step-down circuit. The output of this step-down circuit is connected to the non-inverting input of an operational amplifier. The output of this operational amplifier is connected to its inverting input to form a voltage follower, which outputs the stepped-down positive excitation voltage signal. U 激励正2 ; U 抽头1 The signal is connected to the input of another buck converter, the output of which is connected to the non-inverting input of another operational amplifier. The output of this operational amplifier is connected to its inverting input to form a voltage follower, which outputs the stepped-down signal. U 抽头2 ; By setting up an operational amplifier to form a voltage follower circuit, the load isolation capability of the angle-of-attack acquisition system for the angle-of-attack alarm system is improved, while the acquired voltage is made more stable. (Because the input impedance of the back-end isolation operational amplifier is relatively small (hundreds of kilohms), it is easily affected by the load effect at the signal source end, which can easily lead to signal acquisition distortion. Operational amplifiers have the characteristics of high input impedance (gigahms) and low output impedance. Adding an operational amplifier to form a voltage follower circuit can effectively solve this problem and improve the stability of the acquired signal.)

[0022] The two isolated operational amplifiers in the isolated operational amplifier circuit each include two reference voltages, one of which is the reference voltage at the angle of attack alarm system terminal. V + , V - , GND 1, of which V + , V - The voltage is provided by an isolated power supply circuit. GND 1. Reference ground of the isolated power supply circuit and angle-of-attack alarm system U 激励负1 Connected; the other part is the reference voltage at the angle-of-attack acquisition system end. V + , V - , GND 2, of which V + , V - , GND 2. Connect the two isolation operational amplifiers to the positive and negative power supply voltages and reference ground of the A / D acquisition and MCU processing circuits, respectively. The inputs of the two isolation operational amplifiers are connected to the buck follower circuit... U 激励正2 and U 抽头2 Connected, output terminal U 激励正3 and U抽头3 It is connected to the A / D acquisition and MCU processing circuit to achieve isolated acquisition of the excitation positive voltage signal and the tap voltage signal. By adding an isolation power supply circuit, a reference voltage is provided to the isolation operational amplifier, thereby eliminating common-mode interference caused by ground loops (because the angle-of-attack alarm system can only output...). U 激励正1 , U 激励负1 and U 抽头1 The signal cannot provide a reference power supply for the isolated op-amp, so an isolation power supply circuit is needed to provide a reference voltage for the isolated op-amp.

[0023] The isolated power supply circuit input is an external power supply voltage. VCC and GND Output voltage of isolated power supply circuit V + , V - The positive and negative reference voltages of the input terminals of the two isolated operational amplifiers are connected respectively to provide positive and negative reference voltages for their input terminals. The output terminal of the isolated power supply circuit... GND 3. Reference ground of the input terminal of the isolation operational amplifier and angle-of-attack alarm system U 激励负1 Connected to provide a reference ground signal for the input of the isolation operational amplifier; The A / D acquisition and MCU processing circuit provides a positive reference voltage to the output of the isolation operational amplifier. Negative reference voltage and reference ground signal GND 2. Data collected from the isolation and deployment station U 激励正3 and U 抽头3 It is connected to the A / D acquisition and MCU calculation circuits respectively, and the local angle of attack can be calculated by equation (1). The true angle of attack is calculated using equation (2). ,Right now Equation (1) Equation (2) In the formula, m This is the proportionality coefficient used to convert tap voltage to local angle of attack. n This is the local angle of attack compensation coefficient. m 1 represents the conversion factor between the local angle of attack and the true angle of attack. n 1 represents the true angle of attack compensation coefficient.

[0024] like Figure 2As shown in the embodiment of the present invention, a non-common ground angle-of-attack signal acquisition and calculation circuit and method are provided, including four parts: a buck follower circuit, an isolation operational amplifier circuit, an isolation power supply circuit, and an A / D acquisition and MCU calculation circuit; This explanation uses a pulsating DC wave with a peak value of 30V and a frequency of 800Hz, outputted by an angle-of-attack alarm system, as an example. The angle-of-attack alarm system output... U 激励正1 and U 抽头1 and Figure 1 The step-down circuit 1 and step-down circuit 2 shown are connected, and the reference ground of the step-down follower circuit (the reference ground of the step-down circuit and the reference ground of the voltage follower circuit) is connected to the angle of attack alarm system. U 激励负1 Connected. The positive and negative reference voltages of the operational amplifier are provided by the isolated power supply circuit. The selection of components for the buck follower circuit here needs to refer to the maximum value of the angle-of-attack alarm system output. Generally, the maximum input voltage (or withstand voltage) of the buck follower circuit needs to be greater than 20% of the maximum value of the angle-of-attack alarm system output. The isolation power supply circuit provides a reference voltage for the input of the isolation op-amp and the buck follower circuit. V + , V - and reference ground signal, whose input is external VCC and GND Its output terminal V + , V - The voltage is connected to the input supply voltage of the buck follower circuit and the isolation operational amplifier circuit, and the reference ground signal is connected to the angle of attack alarm system. U 激励负1 The components selected for the isolation power supply here need to meet the power supply voltage requirements of the buck follower circuit and the input terminal of the isolation operational amplifier circuit. The input terminal of the isolation operational amplifier circuit is connected to the output terminal of the buck follower circuit for data acquisition. U 激励正2 and U 抽头2 (Angle of attack voltage signal output by the angle of attack alarm system), taking the ISO124 isolated operational amplifier as an example, its input reference voltage V + , V - Powered by the positive and negative voltages of the isolated power supply circuit, and connected to the reference ground, the isolated power supply circuit and the buck follower circuit are both part of the angle-of-attack alarm system. U 激励负1 ; Output of the isolation operational amplifier circuit U 激励正3 andU 抽头3 Connected to the A / D acquisition and MCU processing circuit, this is the reference voltage at the output of the isolation operational amplifier. V + , V - and reference site GND Both are provided by the A / D acquisition and MCU processing circuit, used for acquisition and processing. and When selecting an A / D chip for the A / D acquisition and MCU processing circuit, the maximum output voltage of the isolation operational amplifier should be considered. Generally, the maximum input voltage of the A / D chip should be 20% greater than the maximum output voltage of the isolation operational amplifier. Signal acquisition process as follows Figure 1 As shown, the angle-of-attack alarm system outputs... U 激励正1 and U 抽头1 The angle-of-attack voltage signal is stepped down and followed by a step-down follower circuit before being output. U 激励正2 and U 抽头2 The isolation operational amplifier circuit is for U 激励正2 and U 抽头2 Isolation sampling was conducted, and the sampling results were obtained. U 激励正3 and U 抽头3 The signal is output to the A / D acquisition and MCU processing circuit for processing. and The solution formula is as follows:

[0025]

[0026] in, m =55、 n =-10, m 1 = 0.661, n 1=4.09, which is determined by the characteristics of the angle of attack alarm system. This example only uses the parameters of a certain angle of attack alarm system. The specific parameters need to be changed according to the characteristics of the angle of attack alarm system.

[0027] Figure 4 This table compares the theoretical and true angles of attack with those measured by this system and those calculated by a general voltage acquisition circuit. Columns 2, 4, and 6 of the comparison table, and columns 3, 5, and 7 of the table... Figure 3The data shows that, due to the influence of common-mode interference, the error of the differential operational amplifier acquisition circuit gradually increases with the increase of the angle of attack, while the error of the circuit designed in this patent is relatively stable, and with the increase of the angle of attack, the error is significantly lower than that of the differential operational amplifier acquisition circuit. This shows that the method significantly improves the acquisition accuracy of local angle of attack and true angle of attack.

[0028] The above description is merely an example of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A non-co-ground angle-of-attack signal acquisition and calculation circuit, characterized in that, include: Buck follower circuit, isolated operational amplifier circuit, isolated power supply circuit, and A / D acquisition and MCU processing circuit; The buck follower circuit includes two buck circuits and two operational amplifiers; used to reduce the excitation positive voltage signal output by the angle-of-attack alarm system according to a preset ratio. U 激励正1 With tap voltage signal U 抽头1 An operational amplifier is used to form a voltage follower circuit to output a stepped-down excitation positive voltage signal. U 激励正2 and tap voltage signal U 抽头2 ; The isolated operational amplifier circuit includes: two isolated operational amplifiers; the inputs of the two isolated operational amplifiers are respectively connected to the voltage follower circuit. U 激励正2 and U 抽头2 Connected, output terminal U 激励正3 and U 抽头3 Connected to the A / D acquisition and MCU processing circuit; Output of the isolated power supply circuit GND 3. Angle of attack warning system U 激励负1 The connected, isolated power supply circuit is used to provide a reference voltage for the input reference voltages of the buck follower circuit and the two isolated operational amplifiers. V + , V - , GND 3; The reference voltage at the output of the two isolated operational amplifiers is connected to the reference voltage inside the A / D acquisition and MCU processing circuit; The A / D acquisition and MCU calculation circuit includes an MCU chip and an A / D acquisition chip, which are used to acquire the excitation positive voltage signal and tap voltage signal output by the isolation operational amplifier circuit and input them to the MCU for calculation of local angle of attack and true angle of attack.

2. The non-co-ground angle-of-attack signal acquisition and calculation circuit according to claim 1, characterized in that, The maximum input voltage of the buck follower circuit is greater than 20% of the maximum output value of the angle of attack alarm system.

3. The non-co-ground angle-of-attack signal acquisition and calculation circuit according to claim 1, characterized in that, The MCU chip uses the following equation (1) to calculate the local angle of attack. The true angle of attack is calculated using the following formula (2). : Equation (1) Equation (2) In the formula, m This is the proportionality coefficient used to convert tap voltage to local angle of attack. n This is the local angle of attack compensation coefficient. m 1 represents the conversion factor between the local angle of attack and the true angle of attack. n 1 represents the true angle of attack compensation coefficient.

4. The non-co-ground angle-of-attack signal acquisition and calculation circuit according to claim 1, characterized in that, The input terminal of the isolated power supply circuit receives external... VCC and GND .

5. The non-co-ground angle-of-attack signal acquisition and calculation circuit according to claim 1, characterized in that, The input impedance of the two operational amplifiers in the buck follower circuit reaches the gigahertz level.

6. The non-co-ground angle-of-attack signal acquisition and calculation circuit according to claim 1, characterized in that, The resistance values ​​of the two step-down circuits in the step-down follower circuit are in the M ohm range.

7. A method for acquiring and calculating angle-of-attack signals without shared ground, characterized in that, It is implemented using the non-co-ground angle-of-attack signal acquisition and calculation circuit as described in any one of claims 1-6.

8. A computer-readable storage medium, characterized in that, include: Memory and processor; The memory is configured to store executable instructions; The processor is configured to implement the method of claim 7 when executing the executable instructions stored in the memory.

9. A computer program product, characterized in that, The computer program product includes instructions that, when executed by a computer, implement the method as described in claim 7.

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