Digital detection method for gap between bearing beam and tool of aircraft fuel tank

Abstract

The invention relates to gap measurement of an aviation product body structure and a positioning tool, in particular to a digital detection method for a gap between an aircraft fuel tank bearing beam and a tool, and belongs to the technical field of aircraft assembly detection. The method has the advantages that the detection time is short, the detection efficiency is high, factors such as human subjective judgment and operation methods are avoided, intelligent measurement of the fuel tank bearing beam and positioning tool butt joint area gap can be achieved, and the corresponding process measurement requirements are met. According to the detection method, a matched measurement device is designed, high-precision detection equipment such as a pressure sensor and an angle sensor is adopted, electronic control executing mechanisms such as a servo sliding table, an electric telescopic rod and a stepping motor are applied, and all-directional measurement of the folding and overlapping area is achieved after a programmed algorithm is carried out.

Description

Technical Field

[0001] The invention relates to the gap measurement between an aviation product body structure and a positioning tool, and in particular to a digital detection method for the gap between an aircraft fuel tank load-bearing beam and a tool, and belongs to the technical field of aircraft assembly detection. Background Art

[0002] Aircraft assembly is an important part of aircraft manufacturing. The coordination method of aircraft manufacturing that ensures the coordination between parts, parts and tooling, and tooling and tooling, and then ensures the accuracy of assembly, is an important feature of aircraft manufacturing. In order to maintain the competitiveness of aviation products and avoid product quality problems, the quality of the aircraft assembly process must be guaranteed. At present, during the parts processing and component assembly process of aircraft, positioning tooling is usually used to position the aircraft assembly parts to ensure that the parts assembly position is accurate and meets the requirements of the digital model of the drawings. At present, during the tooling positioning process in the assembly workshop, there are corresponding gap inspection requirements between the aircraft fuel tank load-bearing beam and the positioning tooling at the joint. According to the requirements of the process regulations, the gap between the end face of the fuel tank structure beam and the end face of the positioning tooling must be measured at the joint position to ensure that the gap value meets the design requirements and ensure the accuracy of aircraft assembly.

[0003] At present, the gap between the aircraft fuel tank load-bearing beam and the tooling is mainly measured by gauge blocks. The size specifications of the gauge blocks are 1mm-10mm and 1.01mm-1.09mm. Therefore, through the combination of gauge blocks, any value in the range of (1.00-10.00)mm can be measured. The measurement gap between the end face of the fuel tank load-bearing beam and the end face of the tooling is required to be 8±1.25mm. The operator measures the gap by holding the gauge block. According to the actual gap value, the operator tests the gap step by step by superimposing and combining the gauge blocks until the combined gauge block and the two measured end faces produce extrusion interference. At this time, the values ​​of the combined multiple gauge blocks are added to obtain the gap value. The detection method of manually combining gauge blocks requires multiple replacement of gauge blocks for test measurement. The measurement process is cumbersome and inefficient. In actual production workshops, the height of the tooling rack is usually more than 3 meters. Since the surface of the gauge block is made of smooth metal, when measuring the gap with multiple gauge blocks, the gauge block often slips out of the operator's hand and falls, causing the operator to find the gauge block on the ground of the tooling rack and re-measure. Sometimes the gauge block is lost, which brings great trouble to the operator. At the same time, manual measurement under high-altitude operation will be affected by human subjective factors, resulting in unstable measurement system and inaccurate measurement data.

[0004] Unstable and inaccurate measurement systems cannot achieve control of assembly quality and are a major hidden danger in aircraft assembly quality inspection. Therefore, in order to improve the current measurement method and improve the accuracy and efficiency of the gap measurement between the aircraft fuel tank load-bearing beam and the positioning tooling, the measurement method needs to be updated.

[0005] By analyzing the existing gap measurement methods of aircraft fuel tank structural beams and positioning tooling, it is found that the measuring tools used by operators on the production site are mainly gauge blocks. The operation method is relatively traditional, and the measurement process is relatively cumbersome. The measurement of the gap must be carried out by trial measurement, so it is necessary to replace the gauge block specifications many times for superposition. The process of replacing the gauge blocks consumes a lot of time, which seriously affects the measurement efficiency. When measuring the gap with multiple superimposed gauge blocks, the gauge blocks may slip from the operator's hands. Due to high-altitude operations, the operator needs to go to the ground to find the fallen gauge blocks again. Sometimes the gauge blocks may fall and be lost, which brings great trouble to the operator. At the same time, since the entire process is manually operated and measured, the measurement results will also be interfered by human subjective factors. These defects and unfavorable factors directly affect the product control capabilities, detection efficiency and accuracy. Summary of the invention

[0006] In order to solve the above problems, an intelligent detection method for the gap between the load-bearing beam and the tooling of an aircraft fuel tank is invented, which can realize the rapid and accurate measurement of the gap between the end face of the structural part and the positioning tooling. The method uses a pressure sensor and an angle sensor for data acquisition, performs signal processing through a control module, and uses a program to calculate the gap, which can realize the full-scale measurement of the overlapping surface of the joint. At the same time, a special digital measuring device suitable for measurement is designed. According to the overlapping form of the joint area between the structural part and the tooling, a servo slide, an electric telescopic rod, a steering gear and other actuators are used to realize the spatial positioning of the measuring component and perform continuous measurement of the measuring area. This intelligent measurement method can improve the measurement efficiency and measurement accuracy, avoid the cumbersome measurement process, get rid of the limitations of the block tool measurement and the inaccuracy of the measurement caused by the subjective influence of human beings, so as to meet the measurement needs and improve the production efficiency of the product.

[0007] The technical solution of the present invention is as follows:

[0008] The digital detection method of the gap between the aircraft fuel tank load-bearing beam and the tooling is as follows:

[0009] Step 1: Before measuring, make sure the operator is in a safe position. Since it is a high-altitude operation, the operator must wear a safety rope to prevent falling from a height due to carelessness during the measurement process;

[0010] Step 2: Check that the cables of the measuring device are connected properly, determine the measuring positions of the tank load-bearing beam and the positioning fixture, and prepare for measurement;

[0011] Step 3: The operator places the measuring device at the preset position on the end face of the load-bearing beam of the oil tank to be tested, and clamps it with two fixing clamps. According to the gap measurement method in 1.6, turn on the power button, the control system is powered on, and the measuring point is selected through the measuring point selection key. The display screen will show the measuring point number;

[0012] Step 4: First, select the 1# measuring point and press the confirmation button. The control module starts to execute the measurement procedure of the 1# measuring point. The system will simultaneously drive the servo slide, electric telescopic rod and rotary motor to move the measuring component to the 1# measuring point. According to the gap measurement method in 1.6, the automatic measurement of the gap will start immediately, and the measured gap value will be displayed on the display screen;

[0013] The gap measurement method is as follows:

[0014] According to the detection requirements, by setting the corresponding program to control the slide, electric telescopic rod, servo and other actuators, the measuring component is placed at the 1# mark point in the gap between the load-bearing beam and the tooling. There is a circular probe with a radius of 2mm on the upper and lower parts of the measuring component, such as Figure 4 First, control the slide stepper motor to rotate forward, and the measuring component moves toward the end face of the tooling. When the upper probe contacts the end face, the pressure sensor value exceeds the previous value, stop the stepper motor from rotating forward, and record the angle sensor value θ4. Then, control the slide stepper motor to rotate reversely, and the measuring component moves toward the end face of the load-bearing beam. When the lower probe contacts the end face, the pressure sensor value also exceeds the previous value, stop the stepper motor from rotating reversely, and record the angle sensor value θ5. The fixed height value of the measuring component is bmm, such as Figure 5 The above method can be used to measure the gap between the load-bearing beam and the end face of the tooling. The specific formula is as follows:

[0015]

[0016] X is the gap between the load-bearing beam to be measured and the end face of the tooling. The θ5, θ4, θ2, θ1, and Y in the formula are detailed in steps 1.4 and 1.6. According to the above detection method, design and write the corresponding measurement program code to realize the automatic measurement of the gap. After the 1# measurement point is detected, the gap measurement of the 2# to 9# marking points is carried out according to the above steps, and the program code for the gap measurement of other measurement points is written according to the specific position of each measurement point on the end face of the load-bearing beam.

[0017] Step 5: After completing the gap measurement of measuring point 1#, press the reset button to return the measuring assembly to its original position. According to steps 3 and 4, select measuring point 2# through the measuring point selection button, and press the confirmation button again. The control system starts to perform the gap measurement of measuring point 2#, and so on. Continue to complete the gap measurement of measuring points 3# to 9# through the same operation and record it on the display screen;

[0018] Step 6: After completing the measurement, record the gap values ​​of all measurement points, return the measurement component to the initial position by pressing the reset button, and turn off the power button;

[0019] Step 7: The operator removes the fixing clips, tidies up and checks the measuring equipment to avoid excess material in the tank.

[0020] Beneficial effects of the present invention:

[0021] An intelligent detection method for the gap between the fuel tank load-bearing beam and the positioning tooling of an aircraft has the advantages of short detection time, high detection efficiency, and is not subject to human subjective judgment and operation methods. It can realize the intelligent measurement of the gap between the fuel tank load-bearing beam and the positioning tooling in the matching area, and meet the corresponding process measurement requirements. The detection method designs a matching measuring device, adopts high-precision detection equipment such as pressure sensors and angle sensors, and applies electric control actuators such as servo slides, electric telescopic rods and stepper motors. After program algorithms, it realizes all-round measurement of the matching overlap area.

[0022] During the product production process, by adopting the above-mentioned intelligent detection method of the gap between the oil tank load-bearing beam and the positioning tooling, the detection efficiency and accuracy of the gap measurement are effectively improved, the labor intensity of the operators is reduced, the measurement method is updated, and the upgrade and transformation from traditional manual measurement to intelligent measurement is realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the measurement component structure;

[0024] Figure 2 It is a schematic diagram of the measurement area of ​​the overlap between the load-bearing beam and the positioning tooling;

[0025] Figure 3 This is the connection diagram of the servo slide and the angle sensor;

[0026] Figure 4 It is a schematic diagram of the measuring components in the load-bearing beam and the positioning fixture;

[0027] Figure 5 It is a schematic diagram of measuring component dimensions;

[0028] Figure 6 It is the axonometric view of the overall structure of the measuring device;

[0029] Figure 7 It is a schematic diagram of the structure of the I detailed measurement component;

[0030] Figure 8 It is the main view of the overall structure of the measuring device;

[0031] Fig. 9 This is a schematic diagram of the module distribution inside the control box;

[0032] Fig.10 This is a diagram of the gap measurement performed by the measuring device. Figure 1 ;

[0033] Fig.11 This is a diagram of the gap measurement performed by the measuring device. Figure 2 .

[0034] Among them, 1-rotating motor, 2-L-shaped bracket, 3-electric telescopic rod, 4-M2 screw, 5-coupling, 6-angle sensor, 7-M3 bolt, 8-fixed bracket, 9-servo slide, 10-display screen, 11-measuring point selection key, 12-confirmation button, 13-reset button, 14-power button, 15-control box, 16-base, 17-rotating arm, 18-measuring head, 19-arm, 20-pressure sensor, 21-M5 nut, 22-M5 bolt, 23-control module, 24-voltage stabilizing module, 25-power module, 26-motor drive module, 27-fixing clamp.

[0035] Specific implementation cases

[0036] Embodiment 1:

[0037] The digital detection method of the gap between the aircraft fuel tank load-bearing beam and the tooling is as follows:

[0038] The method uses a measuring assembly with a pressure sensor such as Figure 1 , equipped with a driving device that can realize spatial movement, mark the points to be measured according to the overlap area of ​​the load-bearing beam and the positioning tooling according to the detection requirements, set the measurement route through the software program, control the driving equipment to transmit the measuring component to the position to be measured in the overlap area, drive the measuring component to measure the gap at the measuring point, the pressure sensor is used to measure the stroke limit of the component, and then the data conversion of the angle sensor is used to achieve accurate measurement of the gap.

[0039] 1.1 On-site measurement and analysis

[0040] Analyze the spatial structure of the site to be measured and the measurement area of ​​the object to be measured. According to the design requirements, analyze the accessibility of the measuring device to the measurement space, determine the installation position and fixing method of the measuring device, and design the corresponding measurement motion trajectory.

[0041] 1.2 Marking measurement points

[0042] Mark the measuring points at the overlap area between the load-bearing beam and the positioning fixture. According to the measurement requirements and the size of the overlap area, mark 9 measuring points on the end surface of the load-bearing beam at the joint according to the specified size, such as Figure 2 .

[0043] 1.3 Hardware system construction and software design

[0044] The hardware system is built based on the STM32 single-chip control module, and the program is developed using Keil MDK software. The pressure sensor uses voltage analog output to transmit the collected data to the control module. The STM32 single-chip has a built-in high-precision AD analog-to-digital converter, which can convert the analog signal collected by the pressure sensor into a digital signal, and set the numerical mark through the program to measure the travel limit of the component. The angle sensor uses the RS485 serial communication mode. By calling the serial communication library function, the measured angle value can be transmitted to the controller in real time, and the angle value is converted into the displacement of the measurement component through the program algorithm formula. The display screen uses a 2.5-inch OLED liquid crystal display module, and transmits data with the control chip through IIC communication mode, which can realize multi-line data drive display. The electric servo slide, electric telescopic rod and motor are mainly used for measuring the spatial positioning of the component, and are driven by the pulse command of the STM32 control module. The power module uses a 12V DC lithium battery, which can directly power the servo slide, electric telescopic rod and motor. At the same time, through the voltage regulator module, the 12V power supply is converted into a 3.3V DC voltage for powering the STM32 microcontroller, and the 12V is converted into a 5.0V DC voltage for powering the pressure sensor and angle sensor.

[0045] 1.4 Angle sensor calibration

[0046] The angle sensor is fixed on the servo slide through a coupling and rotates synchronously with the stepper motor of the servo slide. Figure 3 By writing the corresponding driver, the initial angle of the angle sensor is recorded as θ1, the stepper motor is driven by the control module to drive the angle sensor to rotate synchronously, the moving stroke of the slide block Ymm is recorded by the high-resolution digital display vernier caliper, and then the angle sensor angle θ2 is recorded. Therefore, for every 1 degree rotation of the angle sensor, the slide block stroke is Y / θ2-θ1mm. The angle sensor only needs to be calibrated once and used as data input for subsequent gap calculations.

[0047] 1.5 Pressure sensor calibration

[0048] The control module drives the slide stepper motor and drives the angle sensor to rotate synchronously. The measuring component can be moved in the direction perpendicular to the overlapped end surface through the servo slide, such as Figure 4First, place the measuring component in the gap, visually observe that the probe does not touch the load-bearing beam and the end face of the tooling, and record the output value a of the pressure sensor before contact. When the probe is about to touch the end face of the tooling, monitor the change in the output value of the pressure sensor. For example, when the output value of the pressure sensor changes to a+1, it proves that the probe has touched the end face of the tooling, and a squeezing force is generated on the pressure sensor. At this time, record the angle sensor value θ3. Since the probe and the end face of the tooling have interfered, if the stepper motor continues to rotate, the connector between the slide and the measuring component will have stress deformation, resulting in inaccurate angle measurement. Therefore, by controlling the stepper motor, monitor the value change of the angle sensor value θ3. When θ3 is about to change, record the maximum value of the pressure sensor output value as a+10, proving that when the probe and the end face of the tooling come into contact, the output value of the pressure sensor is between a and a+10, and the angle sensor does not change. Therefore, the pressure sensor value can be set between a and a+10 by writing a program to achieve the travel limit of the measuring component moving in the up and down directions. If the set pressure value exceeds the range of a to a+10, the slide stops moving, that is, the angle sensor stops rotating. The stop of the slide can avoid stress deformation of the connection between the slide and the measuring component. The pressure sensor only needs to be calibrated once and used for data input for subsequent gap calculations.

[0049] 1.6 Gap measurement method

[0050] According to the detection requirements, by setting the corresponding program to control the slide, electric telescopic rod, servo and other actuators, the measuring component is placed at the 1# mark point in the gap between the load-bearing beam and the tooling. There is a circular probe with a radius of 2mm on the upper and lower parts of the measuring component, such as Figure 4 First, control the slide stepper motor to rotate forward, and the measuring component moves toward the end face of the tooling. When the upper probe touches the end face, before the pressure sensor value exceeds a+10, stop the stepper motor from rotating forward, and record the angle sensor value θ4. Then, control the slide stepper motor to rotate reversely, and the measuring component moves toward the end face of the load-bearing beam. When the lower probe touches the end face, before the pressure sensor value exceeds a+10, stop the stepper motor from rotating reversely, and record the angle sensor value θ5. The fixed height value of the measuring component is bmm, such as Figure 5 The above method can be used to measure the gap between the load-bearing beam and the end face of the tooling. The specific formula is as follows:

[0051]

[0052] X is the gap between the load-bearing beam to be measured and the end face of the tooling. The θ5, θ4, θ2, θ1, and Y in the formula are detailed in steps 1.4 and 1.6. According to the above detection method, design and write the corresponding measurement program code to realize the automatic measurement of the gap. After the 1# measurement point is detected, the gap measurement of the 2# to 9# marking points is carried out according to the above steps, and the program code for the gap measurement of other measurement points is written according to the specific position of each measurement point on the end face of the load-bearing beam.

[0053] Embodiment 2:

[0054] Digital measuring device for gap between aircraft fuel tank load-bearing beam and tooling, as shown in the attached Figure 6 , Attachment Figure 7 , Attachment Figure 8 , Attachment Fig. 9 and attached Fig.10 As shown, it mainly includes rotating motor 1, L-shaped bracket 2, electric telescopic rod 3, M2 screw 4, coupling 5, angle sensor 6, M3 bolt 7, fixed bracket 8, servo slide 9, display screen 10, measuring point selection key 11, confirmation button 12, reset button 13, power button 14, control box 15, base 16, rotating arm 17, measuring head 18, arm 19, pressure sensor 20, M5 nut 21, M5 bolt 22, control module 23, voltage stabilizing module 24, power module 25, motor drive module 26, fixing clamp 27 and other components. Among them, L-shaped bracket 2, M2 screw 4, coupling 5, M3 bolt 7, fixed bracket 8, base 16, rotating arm 17, measuring head 18, arm 19, M5 nut 21, M5 bolt 22, fixing clamp 27 constitute the structural part of the measuring tool. The rotating motor 1, the electric telescopic rod 3, the angle sensor 6, the servo slide 9, the display screen 10, the measuring point selection key 11, the confirmation key 12, the reset key 13, the power button 14, the control box 15, the pressure sensor 20, the control module 23, the voltage stabilizing module 24, the power module 25, and the motor driving module 26 constitute the electronic control part of the measuring tool.

[0055] The base 16 is the main supporting structure of the measuring device, and is tightly fitted on the end face of the oil tank load-bearing beam through two fixing clamps 27. The servo slide 9 is fixed to the base 16 by four M5 nuts 21 and M5 bolts 22. The servo slide 9 is composed of a slider, a stepper motor and a lead screw, etc. The up and down movement stroke is 80mm, which is used to drive the measuring component to move vertically to meet the measurement requirements. The lower part of the fixed bracket 8 is connected to the servo slide 9 by four M2 screws 4, and the upper part is connected to the angle sensor 6 by two M3 bolts 7. The fixed bracket 8 can be used to fix the housing of the angle sensor 6. The rotating shaft of the angle sensor 6 and the rotating shaft of the lead screw of the servo slide 9 are connected by a coupling 5. Therefore, the lead screw of the servo slide 9 can rotate synchronously with the shaft of the angle sensor 6. The base of the electric telescopic rod 3 is connected and fixed with the slider of the servo slide 9 by four M3 bolts 7, and the left and right moving range is 100mm, which can realize the translation of the measuring component in the X-axis direction. At the same time, the other end of the electric telescopic rod 3 is connected with the L-shaped bracket 2 by four M5 nuts 21, M5 bolts 22, and the L-shaped bracket 2 is used to fix the rotating motor 1, and is connected and fixed by four M2 screws 4. The shaft of the rotating motor 1 can be inserted into the rotating arm 17 for fixing, and drive it to swing in the Y-axis direction. The rotating arm 17 is connected with the arm 19 in the measuring component by two M3 bolts 7, so the rotating motor 1 can drive the measuring component to swing in the X-axis direction. In summary, the measuring component can move in three-axis space through the servo slide 9, the electric telescopic rod 3 and the rotating motor 1 to realize the positioning of 9 measuring points. As shown in the figure, the measuring component has two measuring heads 18, which are respectively fixed on the upper and lower surfaces of the arm 19 by bonding, and the pressure sensor 20 is inserted into the inside of the arm 19 and connected with four M2 screws 4.

[0056] The control box 15 is fixed on the base 16 by four M5 nuts 21 and M5 bolts 22. The display screen 10, the measuring point selection key 11, the confirmation key 12, the reset key 13 and the power button 14 are installed on the outer shell surface of the control box 15. The control module 23, the voltage stabilizing module 24, the power module 25 and the motor drive module 26 are installed inside the control box 15. The control module 23 is the minimum system board using the STM32 single-chip microcomputer, which is used to communicate data with each module and sensor. The power module 25 uses a 12V lithium battery, which is stepped down by the voltage stabilizing module 24 and can output 5.0V DC and 3.3V DC voltage. The motor drive module 26 is mainly used to drive the stepper motor and the rotary motor 1 in the servo slide 9. The display screen 10 is used to display the measured gap value, the power button 14 is the total power-on switch of the control system, the measuring point selection key 11 is used to select a specific measuring point, and after selecting a measuring point, the corresponding measuring program is started by pressing the confirmation button 12. The reset button 13 is used to initialize the position of the measuring component. By pressing the reset button 13, the measuring component can return to the initial position.

[0057] Embodiment 3:

[0058] The digital detection method of the gap between the aircraft fuel tank load-bearing beam and the tooling is as follows:

[0059] Step 1: Before measuring, make sure the operator is in a safe position. Since it is a high-altitude operation, the operator must wear a safety rope to prevent falling from a height due to carelessness during the measurement process;

[0060] Step 2: Check that the cables of the measuring device are connected properly, determine the measuring positions of the tank load-bearing beam and the positioning fixture, and prepare for measurement;

[0061] Step 3: The operator places the measuring device at the preset position on the end face of the load-bearing beam of the oil tank to be measured, and clamps it with two fixing clamps 27. According to the gap measurement method of 1.6, turn on the power button 14, the control system is powered on, and the measuring point is selected through the measuring point selection key 11, and the display screen 10 will display the measuring point number;

[0062] Step 4: First, select the 1# measuring point and press the confirmation button 12. The control module 23 starts to execute the measuring procedure of the 1# measuring point. The system will simultaneously drive the servo slide 9, the electric telescopic rod 3 and the rotary motor 1 to move the measuring assembly to the 1# measuring point. According to the gap measurement method of 1.6, the automatic measurement of the gap will start immediately, and the measured gap value will be displayed on the display screen 10;

[0063] Step 5: After completing the gap measurement of the 1# measuring point, press the reset button 13 to return the measuring assembly to its original position. According to steps 3 and 4, select the 2# measuring point through the measuring point selection button 11, and press the confirmation button 12 again. The control system starts to perform the gap measurement of the 2# measuring point. Similarly, the gap measurement of the 3# to 9# measuring points is completed through the same operation and recorded on the display screen 10;

[0064] Step 6: After the measurement is completed, record the gap values ​​of all measurement points, return the measurement component to the initial position by pressing the reset button 13, and turn off the power button 14;

[0065] Step 7: The operator removes the fixing clamp 27, sorts out and checks the measuring equipment to avoid excess material in the tank.

Claims

1. A digital measuring device for the gap between the load-bearing beam and the tooling of an aircraft fuel tank, characterized in that: It includes a rotating motor (1), an L-shaped bracket (2), an electric telescopic rod (3), an M2 screw (4), a coupling (5), an angle sensor (6), an M3 bolt (7), a fixed bracket (8), a servo slide (9), a display screen (10), a measuring point selection key (11), a confirmation key (12), a reset key (13), a power button (14), a control box (15), a base (16), a rotating arm (17), a measuring head (18), an arm (19), a pressure sensor (20), an M5 nut (21), an M5 bolt (22), a control module (23), a voltage regulator module (24), a power module (25), a motor drive module (26), and a fixing clamp (27); The base (16) is tightly fitted on the end surface of the oil tank load-bearing beam through two fixing clamps (27); the servo slide (9) is fixed on the base (16) through four M5 nuts (21) and M5 bolts (22); the servo slide (9) is composed of a slider, a stepping motor and a lead screw, and the up and down movement stroke is 80 mm; The lower part of the fixing bracket (8) is connected to the servo slide (9) through four M2 screws (4), and the upper part is connected to the angle sensor (6) through two M3 bolts (7). The fixing bracket (8) is used to fix the housing of the angle sensor (6); The rotating shaft of the angle sensor (6) and the rotating shaft of the lead screw of the servo slide (9) are connected through a coupling (5), and the lead screw of the servo slide (9) can realize synchronous rotation with the shaft of the angle sensor (6); the base of the electric telescopic rod (3) is connected and fixed with the slider of the servo slide (9) through four M3 bolts (7), and the left and right moving range is 100 mm. At the same time, the other end of the electric telescopic rod (3) is connected with the L-shaped bracket (2) through four M5 nuts (21), M5 bolts (22), and the L-shaped bracket (2) is used to fix. The rotating motor (1) is fixedly connected and connected by four M2 screws (4). The shaft of the rotating motor (1) can be inserted into the rotating arm (17) for fixing and driving it to swing in the Y-axis direction. The rotating arm (17) is connected to the arm (19) in the measuring assembly by two M3 bolts (7). The measuring assembly has two measuring heads (18) which are respectively fixed on the upper surface and the lower surface of the arm (19) by bonding. The pressure sensor (20) is inserted into the inside of the arm (19) and connected by four M2 screws (4). The control box (15) is fixed on the base (16) by four M5 nuts (21) and M5 bolts (22); the display screen (10), the measuring point selection key (11), the confirmation key (12), the reset key (13) and the power button (14) are installed on the outer shell surface of the control box (15); the control module (23), the voltage stabilizing module (24), the power module (25) and the motor driving module (26) are installed inside the control box (15).

2. The digital measuring device for the gap between the aircraft fuel tank load-bearing beam and the tooling as claimed in claim 1, characterized in that: The control module (23) is a minimum system board using an STM32 single-chip microcomputer and is used for data communication with various modules and sensors.

3. The digital measuring device for the gap between the aircraft fuel tank load-bearing beam and the tooling as claimed in claim 1 or 2, characterized in that: The power module (25) uses a 12V lithium battery, which is stepped down by a voltage stabilizing module (24) to output 5.0V DC and 3.3V DC voltages.

4. The digital measuring device for the gap between the aircraft fuel tank load-bearing beam and the tooling as claimed in claim 1 or 2, characterized in that: The motor drive module (26) drives the stepping motor and the rotating motor (1) in the servo slide (9).

5. The digital measuring device for the gap between the aircraft fuel tank load-bearing beam and the tooling as claimed in claim 3, characterized in that: The motor drive module (26) drives the stepping motor and the rotating motor (1) in the servo slide (9).

6. The digital measuring device for the gap between the aircraft fuel tank load-bearing beam and the tooling as claimed in claim 1, 2 or 5, characterized in that: The display screen (10) is used to display the measured gap value, the power button (14) is the main power-on switch of the control system, the measurement point selection key (11) is used to select a specific measurement point, and after selecting a measurement point, the corresponding measurement program is started by pressing the confirmation button (12).

7. The digital measurement device for the gap between the aircraft fuel tank load-bearing beam and the tooling as claimed in claim 3, characterized in that: The display screen (10) is used to display the measured gap value, the power button (14) is the main power-on switch of the control system, the measurement point selection key (11) is used to select a specific measurement point, and after selecting a measurement point, the corresponding measurement program is started by pressing the confirmation button (12).

8. The digital measurement device for the gap between the aircraft fuel tank load-bearing beam and the tooling as claimed in claim 4, characterized in that: The display screen (10) is used to display the measured gap value, the power button (14) is the main power-on switch of the control system, the measurement point selection key (11) is used to select a specific measurement point, and after selecting a measurement point, the corresponding measurement program is started by pressing the confirmation button (12).

9. The digital measuring device for the gap between the aircraft fuel tank load-bearing beam and the tooling as claimed in claim 4, characterized in that: The reset button (13) is used to initialize the position of the measurement component.

10. The detection method of the digital measurement device for the gap between the aircraft fuel tank load-bearing beam and the tooling according to any one of claims 1 to 9, characterized in that: Here are the steps: Step 1: Before measuring, make sure the operator is in a safe position. Since it is a high-altitude operation, the operator must wear a safety rope to prevent falling from a height due to carelessness during the measurement process; Step 2: Check that the cables of the measuring device are connected properly, determine the measuring positions of the tank load-bearing beam and the positioning fixture, and prepare for measurement; Step 3: The operator places the measuring device at a preset position on the end face of the load-bearing beam of the oil tank to be measured, and clamps and fixes it with two fixing clamps (27); according to the gap measurement method, the power button (14) is turned on, the control system is powered on, and the measuring point is selected by the measuring point selection key (11), and the display screen (10) will display the measuring point number; The gap measurement method is as follows: According to the detection requirements, the measuring component is placed at the 1# mark point in the gap between the load-bearing beam and the tooling. There is a circular probe with a radius of 2mm on the upper and lower parts of the measuring component. First, the slide stepper motor is controlled to rotate forward, and the measuring component moves toward the end face of the tooling. When the upper probe contacts the end face, the pressure sensor value exceeds the previous value, the stepper motor is stopped from rotating forward, and the angle sensor value θ4 is recorded; then, the slide stepper motor is controlled to reverse, and the measuring component moves toward the end face of the load-bearing beam. When the lower probe contacts the end face, the pressure sensor value also exceeds the previous value, the stepper motor is stopped from reversing, and the angle sensor value θ5 is recorded. The fixed height value of the measuring component is bmm. The gap between the load-bearing beam and the end face of the tooling can be measured by the above method. The specific formula is as follows: Step 4: First, select the 1# measuring point and press the confirmation button (12). The control module (23) starts to execute the measuring program of the 1# measuring point. The system will simultaneously drive the servo slide (9), the electric telescopic rod (3) and the rotary motor (1) to move the measuring assembly to the 1# measuring point. According to the gap measurement method of 1.6, the automatic measurement of the gap will then begin, and the measured gap value will be displayed on the display screen (10). Step 5: After completing the gap measurement at measuring point 1#, press the reset button (13) to return the measuring assembly to its original position; According to step 3 and step 4, the 2# measuring point is selected by the measuring point selection key (11), and the confirmation key (12) is pressed again, and the control system starts to perform the gap measurement of the 2# measuring point. Similarly, the gap measurement of the 3# to 9# measuring points is completed through the same operation and recorded on the display screen (10); Step 6: After the measurement is completed, record the gap values ​​of all measurement points, return the measurement component to the initial position by pressing the reset button (13), and turn off the power button (14); Step 7: The operator removes the fixing clip (27), tidies up and checks the measuring equipment to avoid any excess material in the oil tank.

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