Aircraft mass center measuring device and measuring method

Abstract

The invention discloses an aircraft mass center measuring device and method. The measuring device comprises a base, a bearing combination, a rotating shaft, a storage plate, a measuring block, a balance body, a pull rope fixing shaft, a pull rope, an electronic dynamometer, a level gauge, a locking pin and a fixing base. The base is connected with the rotating shaft through a bearing combination, the storage plate is fixed with the rotating shaft and locked with the base through a locking pin, the fixed seat is fixed on one side of the storage plate, the aircraft can be installed on the two side faces of the fixed seat, the two side faces of the fixed seat are both perpendicular to the upper surface of the storage plate, and the two side faces of the fixed seat are both parallel to the rotation center line of the rotating shaft. The level gauge, the measuring block, the balance body and the pull rope fixing shaft are installed on the other side of the object placing plate, the measuring block and the balance body can independently slide and be locked on the other side of the object placing plate, the center line of the pull rope fixing shaft is parallel to the rotation center line of the rotating shaft, and the electronic dynamometer is connected with the pull rope fixing shaft through the pull rope. Operation, observation and data processing are convenient, and cost is low.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft mass center measurement, and in particular relates to an aircraft mass center measurement device and a measurement method. Background Art

[0002] The mass center often needs to be measured at various stages of the development of aircraft and its subsystems. Most of the existing mass center measurement devices and methods use the principle of multi-point weighing. It is necessary to install multiple sensors at different parts of the object to be measured for simultaneous measurement, and the mass center can only be calculated after comprehensive processing of the measurement data of multiple sensors. The measurement device has a complex structure, high cost, large amount of measurement data, cumbersome calculation process, and even needs to be equipped with a dedicated data processing computer or processor. Some existing patents that use the moment balance principle also have shortcomings. When measuring the mass center, some of them ignore the friction torque in the moment balance analysis, resulting in large measurement errors; some mass center measurement devices and methods are only applicable to symmetrical structures, not to the mass center measurement in the asymmetric shape direction of the aircraft. Summary of the invention

[0003] In view of this, the present invention provides a device and method for measuring the center of mass of an aircraft, which utilizes the principle of torque balance, has a simple structure, does not require the installation of multiple sensors, is convenient to operate, observe and process data, and has low cost. It is not only suitable for measuring the center of mass in the direction of the symmetrical shape of an aircraft, but also suitable for measuring the center of mass in the direction of the asymmetrical shape of an aircraft.

[0004] The technical solution for implementing the present invention is as follows:

[0005] A device for measuring the center of mass of an aircraft, comprising a base, a bearing assembly, a rotating shaft, a storage plate, a measuring block, a balancing body, a rope fixing shaft, a rope, an electronic dynamometer, a level, a locking pin and a fixing seat; wherein, the base is fixed on the ground, the base and the rotating shaft are connected through the bearing assembly, the rotation center line of the rotating shaft is parallel to the horizontal plane, the storage plate is fixed to the rotating shaft, the storage plate and the base are locked through the locking pin, the locking pin is installed on the base, a locking pin hole is reserved at a corresponding position of the storage plate, the fixing seat is fixed to one side of the storage plate, the two side surfaces of the fixing seat can be installed to fix the aircraft, the two side surfaces of the fixing seat are both perpendicular to the upper surface of the storage plate, the two side surfaces of the fixing seat are both parallel to the rotation center line of the rotating shaft, the level, the measuring block and the balancing body are installed on the other side of the storage plate, the level is fixed to the storage plate, the level axis of the level is perpendicular to the rotation center line of the rotating shaft, and the level axis of the level is parallel to the upper surface of the storage plate.

[0006] Furthermore, the measuring block slides alone along the upper surface of the storage plate on the other side of the storage plate or is locked relative to the storage plate. During the sliding or locking process of the measuring block, the mass center of the measuring block is always in the plane formed by the rotation center line of the rotating shaft and the center line of the pull rope fixing shaft.

[0007] Furthermore, the balancing body slides independently on the other side of the storage plate or is locked independently relative to the storage plate.

[0008] Furthermore, the pull rope fixing shaft is fixed to the storage plate, the center line of the pull rope fixing shaft is parallel to the rotation center line of the rotating shaft, the distance between the center line of the pull rope fixing shaft and the upper surface of the storage plate is equal to the distance between the rotation center line of the rotating shaft and the upper surface of the storage plate, the pull rope passes through the center line of the pull rope fixing shaft and is connected to the pull rope fixing shaft, and the electronic dynamometer is connected to the pull rope fixing shaft through the pull rope.

[0009] A method for measuring the center of mass of an aircraft comprises the following steps:

[0010] Step 1: Without installing the aircraft, tightening the rope or installing the electronic dynamometer, first slide the measuring block in the direction of the rotation centerline away from the rotating shaft until the level gauge is roughly horizontal, lock the measuring block, and measure the distance between the mass center of the measuring block and the rotation centerline of the rotating shaft, which is recorded as L4; then slide the balancing body in the direction of the rotation centerline away from the rotating shaft until the level gauge is horizontal, lock the balancing body, and insert the locking pin on the base into the locking pin hole of the storage plate;

[0011] Step 2: Install and fix the aircraft on one side of the fixing seat, and ensure that the rear end face of the aircraft is close to one side of the fixing seat during installation;

[0012] Step 3: Pull out the locking pin on the base from the locking pin hole of the storage plate, and apply a pulling force vertically downward along the plumb line through the electronic dynamometer until the level is horizontal, and record the reading of the electronic dynamometer at this time, which is recorded as F;

[0013] Step 4: Insert the locking pin on the base into the locking pin hole of the storage plate, remove the aircraft from one side of the fixing base, and install and fix it on the other side of the fixing base. During installation, ensure that the rear end face of the aircraft is close to the other side of the fixing base;

[0014] Step 5. Pull out the locking pin on the base from the locking pin hole of the storage plate, and reapply the same pulling force F as in step 3 along the vertical downward direction of the plumb line through the electronic dynamometer. Keep the pulling force applied along the vertical downward direction of the plumb line unchanged, loosen the measuring block, and slowly slide the measuring block along the rotation centerline away from the shaft until the level is horizontal, lock the measuring block, and measure the distance between the mass center of the measuring block and the rotation centerline of the shaft, which is recorded as L5.

[0015] Step 6. Based on the distance L4 and distance L5 obtained in steps 1 and 5, calculate that the distance between the center of mass of the aircraft and the rear end face of the aircraft is [G1*(L5-L4) / (2*G2)]-0.5*L3, where L3 is the distance between the two sides of the fixed seat, G1 is the gravity of the measuring block, and G2 is the gravity of the aircraft.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The present invention uses a measuring block and a balancing body for double balancing. The measuring block has both a balancing function and can also participate in measurement.

[0018] (2) The present invention is designed with a locking pin, which ensures that the aircraft and the fixing seat can be connected, fixed and separated while the fixing seat is stationary.

[0019] (3) The present invention utilizes the principle of moment balance and adjusts the mass center position of the measuring block to achieve the mass center measurement of the spacecraft with only one force measurement. There is no need to install multiple sensors, and the operation, observation and data processing are convenient and low-cost.

[0020] (4) The present invention takes friction torque into account in the torque balance analysis during measurement and uses an electronic dynamometer to measure the tension, which effectively improves the measurement accuracy.

[0021] (5) The present invention is not only applicable to the measurement of the center of mass of an aircraft in the direction of its symmetrical shape, but also applicable to the measurement of the center of mass of an aircraft in the direction of its asymmetrical shape. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the device for measuring the center of mass of an aircraft according to the present invention.

[0023] Figure 2 This is a schematic diagram of the first measurement of the center of mass of an aircraft according to the present invention.

[0024] Figure 3 This is a schematic diagram of the second measurement of the center of mass of a spacecraft according to the present invention.

[0025] Among them, 1-base, 2-bearing assembly, 3-rotating shaft, 4-placing plate, 5-measuring block, 6-balancing body, 7-pull rope fixing shaft, 8-pull rope, 9-electronic dynamometer, 10-level, 11-locking pin, 12-fixed seat, 13-aircraft, 14-aircraft mass center. DETAILED DESCRIPTION

[0026] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0027] like Figure 1As shown, the present invention provides a device for measuring the center of mass of an aircraft, comprising a base 1, a bearing assembly 2, a rotating shaft 3, a placing plate 4, a measuring block 5, a balancing body 6, a pull rope fixing shaft 7, a pull rope 8, an electronic dynamometer 9, a level 10, a locking pin 11 and a fixing seat 12. Among them, the base 1 is fixed on the ground, the base 1 is connected to the rotating shaft 3 through the bearing assembly 2, the rotation center line of the rotating shaft 3 is parallel to the horizontal plane, the placing plate 4 and the rotating shaft 3 are fixed into one body through screws, the placing plate 4 and the rotating shaft 3 rotate relative to the base 1 around the rotation center line of the rotating shaft 3, the placing plate 4 and the base 1 are locked by the locking pin 11, the locking pin 11 is installed on the base 1, and a locking pin hole is reserved at the corresponding position of the placing plate 4. The fixing seat 12 is fixed on the left side of the storage plate 4. The left and right sides of the fixing seat 12 can be installed with a fixed aircraft 13. The left and right sides of the fixing seat 12 are perpendicular to the upper surface of the storage plate 4. The left and right sides of the fixing seat 12 are parallel to the rotation center line of the rotating shaft 3. The distance between the right side of the fixing seat 12 and the rotation center line of the rotating shaft 3 is recorded as L2, and the distance between the left and right sides of the fixing seat 12 is recorded as L3. The level 10, the measuring block 5 and the balance body 6 are installed on the right side of the storage plate 4. The level 10 is fixed to the storage plate 4. The level axis of the level 10 is perpendicular to the rotation center line of the rotating shaft 3, and the level axis of the level 10 is parallel to the upper surface of the storage plate 4.

[0028] The measuring block 5 can slide independently along the upper surface of the storage plate 4 on the other side of the storage plate 4, and the measuring block 5 can be locked independently relative to the storage plate 4. During the sliding and locking process of the measuring block 5, the mass center of the measuring block 5 is always in the plane formed by the rotation center line of the rotating shaft 3 and the center line of the drawstring fixing shaft 7. The balancing body 6 can slide independently on the other side of the storage plate 4 and be locked independently relative to the storage plate 4. The drawstring fixing shaft 7 is installed on the right side in front of the storage plate 4. The center line of the drawstring fixing shaft 7 is parallel to the rotation center line of the rotating shaft 3. The distance between the center line of the drawstring fixing shaft 7 and the upper surface of the storage plate 4 is equal to the distance between the rotation center line of the rotating shaft 3 and the top of the storage plate 4. The distance between the center line of the drawstring fixing shaft 7 and the rotation center line of the rotating shaft 3 is recorded as L1. The drawstring 8 is connected to the drawstring fixing shaft 7, and the drawstring 8 passes through the center line of the drawstring fixing shaft 7. The electronic dynamometer 9 is connected to the drawstring 8.

[0029] The present invention also provides an aircraft mass center measurement method applied to an aircraft mass center measurement device, which is specifically as follows:

[0030] Step 1: Figure 1As shown, the aircraft 13 is not installed, the pull rope 8 is not tightened or the electronic dynamometer 9 is not installed, first slide the measuring block 5 along the rotation centerline direction away from the rotating shaft 3 until the level 10 is roughly horizontal, lock the measuring block 5, measure the distance between the mass center of the measuring block 5 and the rotation centerline of the rotating shaft 3, and record it as L4, then slide the balancing body 6 along the rotation centerline direction away from the rotating shaft 3 until the level 10 is horizontal, lock the balancing body 6, and insert the locking pin 11 on the base 1 into the locking pin hole of the storage plate 4;

[0031] Step 2: Figure 2 As shown, the aircraft 13 is installed and fixed on the right side of the fixing seat 12, and during installation, the rear end surface of the aircraft 13 is ensured to be close to the right side surface of the fixing seat 12;

[0032] Step 3: Figure 2 As shown, the locking pin 11 on the base 1 is pulled out from the locking pin hole of the storage plate 4, and a pulling force is applied vertically downward along the plumb line through the electronic dynamometer 9. The pulling force is slowly increased from zero, and the minimum reading value of the electronic dynamometer 9 is increased each time. During the application of the pulling force, the level 10 is observed until the level 10 is horizontal, and the reading of the electronic dynamometer 9 at this time is recorded, which is recorded as F;

[0033] According to the principle of moment balance, the mechanical balance equation of the level when it is horizontal is as follows:

[0034] (F*L1)-G2*(L2-A)-M=0 (1)

[0035] Wherein, G2 is the gravity of the spacecraft 13, A is the distance between the center of mass 14 of the spacecraft and the rear end surface of the spacecraft 13, and M is the friction torque;

[0036] Step 4: Figure 3 As shown, the locking pin 11 on the base 1 is inserted into the locking pin hole of the storage plate 4, the aircraft 13 is removed from the right side of the fixing seat 12, and is installed and fixed on the left side of the fixing seat 12. During installation, ensure that the rear end surface of the aircraft 13 is close to the left side of the fixing seat 12;

[0037] Step 5: Figure 3 As shown, pull out the locking pin 11 on the base 1 from the locking pin hole of the storage plate 4, reapply the same pulling force F as in step 3 along the vertical downward direction of the plumb line through the electronic dynamometer 9, keep the pulling force applied along the vertical downward direction of the plumb line unchanged, loosen the measuring block 5, slowly slide the measuring block 5 along the direction away from the rotation center line of the rotating shaft 3 until the level 10 is horizontal, lock the measuring block 5, and measure the distance between the mass center of the measuring block 5 and the rotation center line of the rotating shaft 3, which is recorded as L5;

[0038] According to the principle of moment balance, the mechanical balance equation of the level when it is horizontal is as follows:

[0039] (F*L1)+ G1*(L5-L4)- G2*(L2+L3+A)-M=0 (2)

[0040] Wherein, G2 is the gravity of the spacecraft 13, A is the distance between the center of mass 14 of the spacecraft and the rear end surface of the spacecraft 13, and M is the friction torque;

[0041] Step 6: Solve the combination of equations (1) and (2) to obtain the distance between the center of mass of the aircraft 14 and the rear end face of the aircraft 13:

[0042] A=[G1*(L5-L4) / (2*G2)]-0.5*L3 (3)

[0043] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A device for measuring the center of mass of an aircraft, characterized in that: It includes a base, a bearing assembly, a rotating shaft, a storage plate, a measuring block, a balancing body, a rope-fixed shaft, a rope, an electronic dynamometer, a level, a locking pin and a fixing seat; wherein, the base is fixed on the ground, the base and the rotating shaft are connected through a bearing assembly, the rotation centerline of the rotating shaft is parallel to the horizontal plane, the storage plate is fixed to the rotating shaft, the storage plate and the base are locked through a locking pin, the locking pin is installed on the base, a locking pin hole is reserved at a corresponding position of the storage plate, the fixing seat is fixed to one side of the storage plate, the two side surfaces of the fixing seat can be installed with a fixed aircraft, the two side surfaces of the fixing seat are both perpendicular to the upper surface of the storage plate, the two side surfaces of the fixing seat are both parallel to the rotation centerline of the rotating shaft, the level, the measuring block and the balancing body are installed on the other side of the storage plate, the level is fixed to the storage plate, the level axis of the level is perpendicular to the rotation centerline of the rotating shaft, and the level axis of the level is parallel to the upper surface of the storage plate.

2. The device for measuring the center of mass of an aircraft according to claim 1, characterized in that: The measuring block slides alone along the upper surface of the storage plate on the other side of the storage plate or is locked relative to the storage plate. During the sliding or locking process of the measuring block, the mass center of the measuring block is always in the plane formed by the rotation center line of the rotating shaft and the center line of the pull rope fixing shaft.

3. The device for measuring the center of mass of an aircraft according to claim 2, characterized in that: The balancing body slides independently on the other side of the storage plate or is locked independently relative to the storage plate.

4. The device for measuring the center of mass of an aircraft as claimed in claim 3, characterized in that: The pull rope fixing shaft is fixed to the storage plate, the center line of the pull rope fixing shaft is parallel to the rotation center line of the rotating shaft, the distance between the center line of the pull rope fixing shaft and the upper surface of the storage plate is equal to the distance between the rotation center line of the rotating shaft and the upper surface of the storage plate, the pull rope passes through the center line of the pull rope fixing shaft and is connected to the pull rope fixing shaft, and the electronic dynamometer is connected to the pull rope fixing shaft through the pull rope.

5. A method for measuring the center of mass applied to any one of the measuring devices of claims 1-4, characterized in that: The following steps are involved: Step 1: Without installing the aircraft, tightening the rope or installing the electronic dynamometer, first slide the measuring block in the direction of the rotation centerline away from the rotating shaft until the level gauge is roughly horizontal, lock the measuring block, and measure the distance between the mass center of the measuring block and the rotation centerline of the rotating shaft, which is recorded as L4; then slide the balancing body in the direction of the rotation centerline away from the rotating shaft until the level gauge is horizontal, lock the balancing body, and insert the locking pin on the base into the locking pin hole of the storage plate; Step 2: Install and fix the aircraft on one side of the fixing seat, and ensure that the rear end face of the aircraft is close to one side of the fixing seat during installation; Step 3: Pull out the locking pin on the base from the locking pin hole of the storage plate, and apply a pulling force vertically downward along the plumb line through the electronic dynamometer until the level is horizontal, and record the reading of the electronic dynamometer at this time, which is recorded as F; Step 4: Insert the locking pin on the base into the locking pin hole of the storage plate, remove the aircraft from one side of the fixing base, and install and fix it on the other side of the fixing base. During installation, ensure that the rear end face of the aircraft is close to the other side of the fixing base; Step 5. Pull out the locking pin on the base from the locking pin hole of the storage plate, and reapply the same pulling force F as in step 3 along the vertical downward direction of the plumb line through the electronic dynamometer. Keep the pulling force applied along the vertical downward direction of the plumb line unchanged, loosen the measuring block, and slowly slide the measuring block along the rotation centerline away from the shaft until the level is horizontal, lock the measuring block, and measure the distance between the mass center of the measuring block and the rotation centerline of the shaft, which is recorded as L5. Step 6. Based on the distance L4 and distance L5 obtained in steps 1 and 5, calculate that the distance between the center of mass of the aircraft and the rear end face of the aircraft is [G1*(L5-L4) / (2*G2)]-0.5*L3, where L3 is the distance between the two sides of the fixed seat, G1 is the gravity of the measuring block, and G2 is the gravity of the aircraft.

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