CN103513577A - A displacement sensor simulation circuit - Google Patents

Abstract

The invention belongs to the field of fly-by-wire flight control system test technology, and in particular relates to a displacement sensor simulation circuit. The simulation circuit of the displacement sensor of the present invention can be divided into three parts: an input signal processing circuit, a signal modulation circuit, and an output signal processing circuit. The simulation circuit receives the analog output signal and decomposes it into two DC analog signals corresponding to the magnitudes of the two side manipulation quantities; then uses the principle of amplitude modulation to modulate the two DC analog signals into two AC analog signals; then The feedback circuit composed of the operational amplifier and the triode is used to improve the driving ability of the signal, and the drive transformer is used as the output, thereby simulating the secondary output impedance characteristics of the linear displacement sensor. The invention has simple design and low cost, and can well simulate the signal of the displacement sensor.

Description

A Displacement Sensor Simulation Circuit

technical field

The invention belongs to the field of fly-by-wire flight control system test technology, and in particular relates to a displacement sensor simulation circuit.

Background technique

In the aircraft of the fly-by-wire flight control system, the pilot control sensor is the signal source of the manual control of the aircraft, which converts the pilot's control displacement (or control force) of the control stick and pedals into a voltage signal proportional to it, and sends it to into the flight control computer. Fly-by-wire flight control systems or control enhancement systems generally use displacement sensors as the driver's manipulation sensors. Driver manipulation sensors come in two forms:

Linear Variable Differential Transformer (Displacement Transducer, LVDT): Converts linear displacement into a voltage signal.

Rotary Variable Differential Transformer (Angular Displacement Transducer, RVDT): Converts angular displacement into a voltage signal.

These two sensors have the characteristics of simple structure, convenient use, wide adaptable ambient temperature range, high sensitivity and large output signal, more importantly, high reliability and long life, and are widely used. Due to the large measuring range of LVDT, wide linear output range, convenient installation and wider application.

In the test, the flight control computer needs to collect the signals of these sensors. The construction of the traditional physical environment often takes a long time and costs a lot. Moreover, it is difficult to complete the construction of faults and automatic testing of specific functions in a physical environment.

Contents of the invention

The technical problem to be solved by the present invention is to provide a displacement sensor simulation circuit to realize electronic simulation of displacement sensor signals.

The technical solution of the present invention is: a displacement sensor simulation circuit, characterized in that: the simulation circuit can be divided into three parts, namely: input signal processing circuit, signal modulation circuit, output signal processing circuit; input signal processing circuit receives input signal processing circuit from For the excitation signal of the flight control computer, connect its high-end EX+ to the input terminal 1 of capacitor C1, and connect the low-end EX- to the input terminal 1 of capacitor C2. Input 2 is connected to resistor R2 input 1 and operational amplifier U1 input 1, resistor R3 input 2 is connected to operational amplifier input 2 and resistor R4 input 1, resistor R4 input 2 is grounded, resistor R2 input 2 is connected to operational amplifier After inputting terminal 3, it is output as carrier signal VCAR, the input terminal 1 of resistor R5 is connected to VCC, the input terminal 2 of resistor R5 is connected to terminal 1 of resistor R6, the input terminal 2 of resistor R6 is connected to terminal 1 of resistor R7, and the input terminal 2 of resistor R7 is grounded. R6 input terminal 3 is connected to operational amplifier input terminal 2, operational amplifier input terminal 1 is connected to operational amplifier input terminal 3 and resistor R12 input terminal 1, R12 input terminal 2 is connected to operational amplifier input terminal 1, resistor R13 input terminal 2 and resistor R14 input terminal 1 Terminal, from the simulation upper computer analog control signal high-end CON+ connection resistor R8 input terminal 1, from the simulation upper computer analog control signal low-end CON- connection resistor R9 input terminal 1, resistor R8 input terminal 2 connected to the operational amplifier input terminal 1 and resistor R10 Input terminal 1, resistor R9, input terminal 2 connects resistor R11 input terminal 1 and operational amplifier input terminal 2, resistor R11 input terminal 2 is grounded, resistor R10 input terminal 2 connects resistor R13 input terminal 1 and operational amplifier input terminal 3, and acts as a sensor Coil A simulation structure signal size DC signal CommandA output, resistor R14 input 2 terminals connected to operational amplifier U3 input 3 terminals as sensor coil B simulation structure signal size DC signal CommandB output; signal modulation circuit receives the signal processed by the input signal circuit, and converts Carrier signal VCAR is connected to input 3 of analog multiplier U1 and U2, CommandA signal is connected to input 1 of analog multiplier U1 and U2, input 2, 4 and 6 of analog multiplier U1 and U2 are grounded, and input 5 is grounded Connect to the negative terminal VEE of the power supply, input 8 is connected to the high-end VCC of the power supply, the output terminal 7 of the analog multiplier U1 outputs the AM signal OUTA, and the output terminal 7 of the analog multiplier U2 outputs the AM signal OUTB; the output signal processing circuit receives the AM signals OUTA and OUTB , Connect OUTA to the input terminals 2 of operational amplifiers U1 and U2 respectively, the input terminal 1 of operational amplifier U1 is connected to the input terminal 3 of transistor Q1 and Q2 and the input terminal 1 of the transformer coil, and the input terminal 3 of operational amplifier U1 is connected to the input terminal of transistor Q1 and Q2 Terminal 1, the high-end VCC of the power supply is connected to the input terminal 2 of the transistor Q1, the low-end VEE of the power supply is connected to the input terminal 2 of the transistor Q2, and the output terminal of the transformer coil T1 Input terminal 2 is grounded, transformer coil output terminal 3 simulates output sensor secondary coil A high signal CoilA+, transformer coil output terminal 4 simulates sensor secondary coil A low signal CoilA-, operational amplifier U2 input terminal 1 is connected to transistor Q3, Q4 Input terminal 3 and input terminal 1 of the transformer coil, input terminal 3 of the operational amplifier U2 is connected to the input terminal 1 of the triode Q3 and Q4, the high-end VCC of the power supply is connected to the input terminal 2 of the transistor Q3, and the low-end VEE of the power supply is connected to the input terminal 2 of the transistor Q4 , Transformer coil T2 input terminal 2 is grounded, transformer coil output terminal 3 simulates output sensor secondary coil B high signal CoilB+, transformer coil output terminal 4 simulates sensor secondary coil A low signal CoilB-, line displacement sensor two secondary side signals are been simulated.

The invention is simple in design, low in cost, can well simulate the signal of the displacement sensor, and can bring the following beneficial effects: firstly, it reduces the demand for the physical environment of the flight control test, thereby shortening the construction period of the test environment and reducing the cost; The second is that the signal size of each redundancy sensor can be manually adjusted at will during use, and it is convenient to set sensor faults such as constant deviation, stuck, constant gain, and open circuit, which greatly facilitates the fault injection of the flight control system and reduces the test time. in the labor burden.

Description of drawings

Fig. 1 is the principle block diagram of displacement sensor emulation circuit of the present invention;

Fig. 2 is the input signal processing circuit diagram in the displacement sensor emulation circuit of the present invention;

Fig. 3 is a signal modulation circuit diagram in the displacement sensor simulation circuit of the present invention;

Fig. 4 is a schematic diagram of the output signal processing circuit in the displacement sensor emulation circuit of the present invention.

Detailed ways

The specific embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

Referring to Fig. 1, a kind of displacement sensor emulation circuit of the present invention realizes the emulation principle is: described emulation circuit receives the analog output signal that replaces the actual physical manipulated quantity size by software control from the host computer, based on the adjustable value set in the circuit Corresponding to the two side and value voltage signals of the sensor, it is decomposed into two DC analog signals corresponding to the magnitude of the two side control quantities; then, according to the AC excitation signal from the flight control computer, the two DC analog signals are modulated by the principle of amplitude modulation These two AC analog signals correspond to the output signals of the simulated sensor; then use the feedback circuit composed of the operational amplifier and the triode to improve the driving ability of the signal, and drive the transformer as the output, thereby simulating the linear displacement sensor. Secondary output impedance characteristics.

Referring to Fig. 2, Fig. 3, Fig. 4, a kind of displacement sensor simulation circuit of the present invention can be divided into three parts, namely: input signal processing circuit, signal modulation circuit, output signal processing circuit; For the computer’s excitation signal, connect its high-end EX+ to the input terminal 1 of capacitor C1, and connect the low-end EX- to the input terminal 1 of capacitor C2. Terminal connected to resistor R2 input 1 and operational amplifier U1 input 1, resistor R3 input 2 connected to operational amplifier input 2 and resistor R4 input 1, resistor R4 input 2 to ground, resistor R2 input 2 to operational amplifier input 3 After the terminal is used as the carrier signal VCAR output, the resistor R5 input terminal 1 is connected to VCC, the resistor R5 input terminal 2 is connected to the resistor R6 input terminal 1, the resistor R6 input terminal 2 is connected to the resistor R7 input terminal 1, the resistor R7 input terminal 2 is grounded, and the resistor R6 input terminal Terminal 3 is connected to input terminal 2 of the operational amplifier, input terminal 1 of the operational amplifier is connected to input terminal 3 of the operational amplifier and input terminal 1 of the resistor R12, and input terminal 2 of R12 is connected to the input terminal 1 of the operational amplifier, input terminal 2 of the resistor R13 and input terminal 1 of the resistor R14. The high-end CON+ of the analog control signal from the simulation host computer is connected to the input terminal 1 of the resistor R8, the low terminal CON- of the analog control signal from the simulation host computer is connected to the input terminal 1 of the resistor R9, and the input terminal 2 of the resistor R8 is connected to the input terminal 1 of the operational amplifier and the input terminal 1 of the resistor R10 Terminal, resistor R9 input terminal 2 is connected to resistor R11 input terminal 1 and operational amplifier input terminal 2, resistor R11 input terminal 2 is grounded, resistor R10 input terminal 2 is connected to resistor R13 input terminal 1 and operational amplifier input terminal 3, and is used as a sensor coil A simulation structure signal size DC signal CommandA output, resistor R14 input 2 terminals connected to the operational amplifier U3 input 3 terminals as a sensor coil B simulation structure signal size DC signal CommandB output; signal modulation circuit receives the signal processed by the input signal circuit and converts the carrier The signal VCAR is connected to the input 3 terminals of the analog multipliers U1 and U2, the CommandA signal is connected to the input 1 terminals of the analog multipliers U1 and U2, the inputs 2, 4 and 6 of the analog multipliers U1 and U2 are grounded, and the input 5 terminals are connected to To the negative terminal VEE of the power supply, the input 8 is connected to the high-end VCC of the power supply, the output terminal 7 of the analog multiplier U1 outputs the amplitude modulation signal OUTA, and the output terminal 7 of the analog multiplier U2 outputs the amplitude modulation signal OUTB; the output signal processing circuit receives the amplitude modulation signals OUTA and OUTB, Connect OUTA to operational amplifier U1, U2 input 2, operational amplifier U1 input 1 to triode Q1, Q2 input 3 and transformer coil input 1, operational amplifier U1 input 3 to triode Q1, Q2 input 1 The high-end VCC of the power supply is connected to the input terminal 2 of the transistor Q1, the low-end VEE of the power supply is connected to the input terminal 2 of the transistor Q2, and the input terminal 2 of the transformer coil T1 is grounded , transformer coil output terminal 3 simulates output sensor secondary coil A high signal CoilA+, transformer coil output terminal 4 simulates sensor secondary coil A low signal CoilA-, operational amplifier U2 input terminal 1 is connected to transistor Q3, Q4 input terminal 3 and The input terminal 1 of the transformer coil, the input terminal 3 of the operational amplifier U2 are connected to the input terminal 1 of the transistor Q3 and Q4, the high-end VCC of the power supply is connected to the input terminal 2 of the transistor Q3, the low-end VEE of the power supply is connected to the input terminal 2 of the transistor Q4, and the transformer coil T2 Input terminal 2 is grounded, transformer coil output terminal 3 simulates output sensor secondary coil B high signal CoilB+, transformer coil output terminal 4 simulates sensor secondary coil A low signal CoilB-, and the two secondary side signals of the linear displacement sensor are simulated.

In the specific implementation process, the analog displacement sensor LVDT/RVDT circuit needs to solve the following problems:

① Impedance matching problem. The input and output impedance of the displacement sensor simulation circuit should basically meet the impedance characteristic requirements of the displacement sensor.

② Correspondence between input and output signals.

The displacement sensor simulation circuit should be able to receive the excitation signal from the flight control computer, and output an AC signal with the same frequency as the excitation signal and a small phase lag.

③ output signal voltage and.

It can be seen from the principle of the displacement sensor that the sum of the secondary coil output voltages of the displacement sensor simulation circuit should be a constant value.

④ Circuit-related parameters are easy to adjust.

In the designed circuit, different characteristics should be taken into consideration, and adjustable measures should be taken, so that the designed circuit has greater versatility.

From the perspective of external electrical input and output characteristics, the displacement sensor simulation circuit has the following differences: In the input stage, an analog electrical signal input terminal replaces the physical input signal of the manipulator, which is convenient for the application of computer control.

The displacement sensor simulation circuit is mainly realized by applying the principle of amplitude modulation. AM is to use the modulation signal x to control the amplitude of the high-frequency carrier signal. The displacement sensor simulation circuit generates a high-frequency carrier signal based on the excitation signal of the original sensor primary side, and generates two modulation signals based on the simulated computer simulation command signal (representing the position of the LVDT and RVDT iron core), and adjusts it through the corresponding circuit. Afterwards, the corresponding signals are output as two secondary sides.

When designing the circuit, the present invention has noticed the following points:

①Amplitude modulation circuit principle

如图3所示，X₂，Y₂，Z端接地，上述电路传递函数为：

$\mathrm{OutB}=\frac{\mathrm{CommandB}\×\mathrm{Vcar}}{10V}.$ The amplitude modulation circuit is the core part of the analog displacement sensor circuit. It is realized by two pieces of AD633, and each AD633 corresponds to generate an AM signal, and the transfer function of AD633 is

As shown in Figure 3, X ₂ , Y ₂ , and Z terminals are grounded, and the transfer function of the above circuit is:

$\mathrm{OutB}=\frac{\mathrm{Command\; B}\×\mathrm{Vcar}}{10V}.$

② Reference voltage supply circuit.

Output signal processing circuit In Figure 4, OutA and OutB are only processed with the same amplitude, so that the driving ability is improved, and thus output as a circuit board. In order to ensure that the output of the circuit board meets the output characteristics of the displacement sensor, it is necessary to ensure that the sum of the two outputs of the amplitude modulation circuit is a constant value.

That is: OutA+OutB=constant value

Vcar in the circuit is a constant value, so it can be known from the above relational expression, as long as CommandA+CommandB is a constant value. Among them, CommandA is the corresponding signal size provided by the computer to represent the position of the LVDT and RVDT iron cores. In the above circuit, CommandA is the computer command to input the corresponding value voltage value. In the input signal processing circuit of the displacement sensor simulation circuit, a reference voltage is provided in Figure 2. The slip resistance can partially adjust the voltage value. CommandB is the difference between the reference sum value voltage and the computer command voltage, thus ensuring the output and value of the amplitude modulation circuit. constant.

③ output signal drive circuit.

The output and input current of the TTL chip is generally relatively small, about 20mA. In order to ensure its load capacity, the following drive circuit is designed by using the nonlinear feedback characteristics of the operational amplifier, which greatly improves the load capacity.

④Other characteristics of the circuit

Input signal conversion: The displacement sensor simulation circuit performs a differential conversion on the input signal, so that each signal is converted into a signal at the same ground as the circuit.

Input and output isolation: In order to simulate the relevant impedance characteristics and ensure the reliability of the circuit. Different isolation measures are taken for the input and output circuits, which improves the connection safety of the input and output devices and makes the input and output impedances close.

In one embodiment of the present invention, the operational amplifier adopts LM124J chip, the analog multiplier adopts AD633JN, the transistors Q1 and Q3 adopt S8050, and the transistors Q3 and Q4 adopt S8550.

Claims (1)

1. a displacement sensor emulation circuit, it is characterized in that: described emulation circuit can be divided into three parts, namely: input signal processing circuit, signal modulation circuit, output signal processing circuit; Input signal processing circuit receives the excitation from flight control computer signal, connect its high-end EX+ to the input terminal 1 of capacitor C1, connect the low-end EX- to the input terminal 1 of capacitor C2, connect the input terminals 2 of capacitors C1 and C2 to the input terminal 1 of resistors R1 and R3 respectively, and connect the input terminal 2 of resistor R1 to the resistor R2 input terminal 1 and operational amplifier U1 input terminal 1, resistor R3 input terminal 2 connected to operational amplifier input terminal 2 and resistor R4 input terminal 1, resistor R4 input terminal 2 to ground, resistor R2 input terminal 2 connected to operational amplifier input terminal 3 as Carrier signal VCAR output, resistor R5 input terminal 1 is connected to VCC, resistor R5 input terminal 2 is connected to resistor R6 input terminal 1, resistor R6 input terminal 2 is connected to resistor R7 input terminal 1, resistor R7 input terminal 2 is connected to ground, resistor R6 input terminal 3 is connected to Operational amplifier input 2, operational amplifier input 1 is connected to operational amplifier input 3 and resistor R12 input 1, R12 input 2 is connected to operational amplifier input 1, resistor R13 input 2 and resistor R14 input 1, from the simulation host The high end CON+ of the computer analog control signal is connected to the input terminal 1 of the resistor R8, and the low terminal CON- of the simulated control signal from the upper computer is connected to the input terminal 1 of the resistor R9, and the input terminal 2 of the resistor R8 is connected to the input terminal 1 of the operational amplifier and the input terminal 1 of the resistor R10. R9 input terminal 2 is connected to resistor R11 input terminal 1 and operational amplifier input terminal 2, resistor R11 input terminal 2 is grounded, resistor R10 input terminal 2 is connected to resistor R13 input terminal 1 and operational amplifier input terminal 3, and used as sensor coil A simulation structure Signal size DC signal CommandA output, resistor R14 input 2 terminals connected to operational amplifier U3 input 3 terminals as sensor coil B simulation structure signal size DC signal CommandB output; signal modulation circuit receives the signal processed by the input signal circuit, and connects the carrier signal VCAR Connect to input 3 of analog multiplier U1, U2, CommandA signal is connected to input 1 of analog multiplier U1, U2, input 2, 4, 6 of analog multiplier U1, U2 are grounded, input 5 is connected to power negative Terminal VEE, input 8 is connected to the high-end VCC of the power supply, the analog multiplier U1 outputs the amplitude modulation signal OUTA at the output terminal 7, and the analog multiplier U2 outputs the amplitude modulation signal OUTB at the output terminal 7; the output signal processing circuit receives the amplitude modulation signals OUTA and OUTB, and converts OUTA respectively Connect to input 2 of operational amplifier U1 and U2, input 1 of operational amplifier U1 is connected to input 3 of transistor Q1 and Q2 and input 1 of transformer coil, input 3 of operational amplifier U1 is connected to input 1 of transistor Q1 and Q2, power supply The high-end VCC is connected to the input terminal 2 of the transistor Q1, the low-end VEE of the power supply is connected to the input terminal 2 of the transistor Q2, and the input terminal 2 of the transformer coil T1 is grounded. Transformer coil output terminal 3 simulates output sensor secondary coil A high signal CoilA+, transformer coil output terminal 4 simulates output sensor secondary coil A low signal CoilA-, operational amplifier U2 input terminal 1 is connected to triode Q3, Q4 input terminal 3 and The input terminal 1 of the transformer coil, the input terminal 3 of the operational amplifier U2 are connected to the input terminal 1 of the transistor Q3 and Q4, the high-end VCC of the power supply is connected to the input terminal 2 of the transistor Q3, the low-end VEE of the power supply is connected to the input terminal 2 of the transistor Q4, and the transformer coil T2 Input terminal 2 is grounded, transformer coil output terminal 3 simulates output sensor secondary coil B high signal CoilB+, transformer coil output terminal 4 simulates sensor secondary coil A low signal CoilB-, and the two secondary side signals of the linear displacement sensor are simulated.

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