An excitation auxiliary device and calculation method based on modal test quality line

Abstract

The present invention discloses an excitation auxiliary device and calculation method based on modal test mass line, which belongs to the technical field of rigid body inertia parameter identification. The device includes a pair of locking mechanisms, and the two ends of the test piece are arranged on the locking mechanisms. Each locking mechanism includes 4 locking units, and the 4 locking units are connected by fastening steel wires to form a rectangular frame; the structure can test the inertia parameters of complex rotating parts by the mass line method, and the flexible combined structure of the excitation auxiliary device itself can be applied to the size of the test piece that varies within a certain range; through analysis and calculation, the influence of the auxiliary excitation device on the test result of the test piece can be eliminated, and the inertia parameters of the test piece can be correctly calculated, which greatly improves the test accuracy and efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of rigid body inertia parameter identification, in particular to an excitation auxiliary device and a calculation method based on a modal test mass line. Background Art

[0002] Efficient, convenient and accurate acquisition of rigid body inertia parameters of complex components such as missiles and transmission shafts has always been a hot topic and a difficult issue. The inertia parameter measurement method based on modal test mass line has been studied by a large number of scholars and applied by enterprises due to its simplicity and efficiency. However, when testing complex rotating structures, this method often faces the problem of difficulty in exciting the vibration mode of the rotating shaft of the test piece, resulting in low accuracy in the solution of the inertia parameters. In response to the above test experimental problems, an excitation auxiliary device and calculation method are designed, which can achieve the excitation of vibration modes of complex parts of different sizes, facilitate installation and disassembly, and propose a method to eliminate the influence of the additional device on the inertia parameter results of the original test piece. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide an excitation auxiliary device and a calculation method based on a modal test mass line.

[0004] The technical solution for achieving the purpose of the present invention is:

[0005] An excitation auxiliary device based on a modal test mass line includes a pair of locking mechanisms, two ends of the test piece are arranged on the locking mechanisms, each locking mechanism includes four locking units, and the four locking units are connected by fastening steel wires to form a rectangular frame;

[0006] The locking unit is a right-angled base with a groove at one end of the base. A ratchet rotating shaft is arranged in the groove. Both ends of the ratchet rotating shaft pass through the base. A ratchet is fixed to one end of the ratchet rotating shaft. A needle base is arranged on the base above the ratchet. The needle base is fixed to the base. A needle shaft is arranged on the needle base. A needle is arranged at the end of the needle shaft. The needle engages with the ratchet. Two wire sleeves are arranged at intervals on the ratchet rotating shaft in the groove. A wire shaft parallel to the ratchet rotating shaft is arranged at the front lower part of the ratchet rotating shaft. A fine adjustment sheet is arranged on the bottom of the groove in front of the wire shaft. A vertically arranged guide shaft is respectively provided at both ends of the plate, and the guide shaft passes through the fine adjustment plate. A threaded hole is provided in the middle of the fine adjustment plate between the two guide shafts, and the fine adjustment bolt is passed through the base at the top of the groove into the groove and connected with the threaded hole on the fine adjustment plate and passes through the base at the bottom of the groove; fastening steel wires are respectively wound around the wire sleeves, and the ends of the fastening steel wires are led out from the wire sleeves, bypass the bottom of the wire shaft, and pass through the gap between the wire shaft and the fine adjustment plate, and pass through the groove from the upper surface of the fine adjustment plate, and are connected to the steel wire fastening hole on the other end of the adjacent locking unit base through a fastening bolt.

[0007] The base body is provided with a magnet groove on the inner side at a right angle, and a magnet is embedded in the magnet groove. The magnetic force of the magnet is used to preliminarily fix the test piece arranged on the locking mechanism.

[0008] The ratchet rotating shaft has an end surface at one end of the ratchet that is designed as a hexagon, which is convenient for tightening with tools.

[0009] The method for measuring and calculating inertia parameters using the above-mentioned excitation auxiliary device based on the modal test mass line includes the following steps:

[0010] 1) Place the excitation auxiliary device on the workbench, set the two ends of the test piece on the locking mechanism, and use the magnet in the base to preliminarily fix the position of the test piece;

[0011] 2) Lead the fastening steel wire out of the steel wire sleeve, pass around the bottom of the wire shaft, pass through the gap between the wire shaft and the fine adjustment piece, pass through the groove on the upper surface of the fine adjustment piece, and connect with the steel wire fastening hole on the other end of the adjacent locking unit base through the fastening bolt and tighten;

[0012] 3) After determining the length of the tightening wire, twist the ratchet shaft to preliminarily tighten the wire rope; after the preliminarily tightening, twist the fine adjustment bolt to raise the fine adjustment piece and tighten the wire rope. During this process, use a force hammer to knock the excitation auxiliary device to check the tightness. After the tightening conditions are met, stop twisting the fine adjustment bolt to complete the tightening of the test piece. Use the modal hammer method to knock the corner points at the right angles of the auxiliary device to ensure at least 2 knocks in the XYZ direction, obtain the frequency response function of the test piece, and calculate the inertia parameters of the entire system (including the excitation auxiliary device) according to the mass line algorithm;

[0013] 4) Determine the mass m of the excitation auxiliary device 0 and the moment of inertia of a point in the base of the relative excitation auxiliary device and product of inertia This point is defined as the reference point. The excitation devices are arranged in pairs in a symmetrical manner. The excitation devices are arranged at the outermost side of a certain direction of the coordinate axis of the test piece to excite the sixth-order rigid body mode of the entire system.

[0014] 5) After the device is arranged, measure the response coordinates of the sensor and the coordinates of the hammer excitation, and at the same time measure the coordinates of the reference point in the reference coordinate system of the test piece (x 0 y 0 z 0 ), calculate the inertia parameters of the entire system according to the test results of the mass line and the calculation method of the following formula (1) and formula (2):

[0015]

[0016] In formula (1), the excitation force F applied at a point i on the rigid body to be measured is i =(f ix f iy f iz ), F i Angular acceleration of the object under test under excitation, (x c y c z c ) is the center of mass of the test system, is the acceleration of point j relative to the reference point O, m a is the total mass of the test system (the test piece and the excitation auxiliary device);

[0017]

[0018] In formula (2), (x Ji y Ji z Ji ) is the coordinate of the excitation point,

[0019] 6) Calculate the actual mass m of the test piece by using the following formulas (3), (4), (5) and (6): z , Inertia parameters of the test piece (J z xx J z yy J z zz ), product of inertia (J z yz J z xz J z xy ) Heat transfer centroid coordinates (x z c y z c z z c ):

[0020] m z =m a -m 0 (3)

[0021]

[0022]

[0023]

[0024] The center of mass position is determined by the mass distribution of the test piece. Since the excitation auxiliary devices are in pairs and symmetrically distributed, the influence on the center of mass can be ignored.

[0025] The present invention provides an excitation auxiliary device and a calculation method based on a modal test mass line. The device has a simple structure and can perform inertia parameter testing on complex rotating parts by using a mass line method. The flexible modular structure of the excitation auxiliary device itself can be applied to the sizes of the test pieces that vary within a certain range. Through analysis and calculation, the influence of the auxiliary excitation device on the test results of the test pieces can be eliminated, the inertia parameters of the test pieces can be correctly calculated, and the test accuracy and efficiency can be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of fixing the piece under test on the excitation auxiliary device;

[0027] Figure 2 is a structural schematic diagram of a locking unit;

[0028] Figure 3 for Figure 2 Enlarged view of part A in the middle;

[0029] Figure 4 is a side sectional view of the locking unit;

[0030] Figure 5 for Figure 4 Enlarged view of middle part B;

[0031] Figure 6 A front view of the locking unit having a groove end;

[0032] In the figure: 1. Test piece 2. Locking unit 3. Fastening wire 4. Fine adjustment bolt 5. Groove 6. Guide shaft 7. Fine adjustment piece 8. Ratchet rotating shaft 9. Ratchet 10. Hexagonal end face of ratchet rotating shaft 11. Clamping needle 12. Clamping needle shaft 13. Clamping needle base 14. Conductor shaft 15. Wire sleeve 16. Magnet. DETAILED DESCRIPTION

[0033] The content of the present invention is further described below in conjunction with the drawings and embodiments, but the invention is not limited thereto.

[0034] Example:

[0035] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown:

[0036] An excitation auxiliary device based on a modal test quality line includes a pair of locking mechanisms, two ends of a test piece 1 are arranged on the locking mechanisms, each locking mechanism includes four locking units 2, and the four locking units 2 are connected by fastening steel wires to form a rectangular frame;

[0037] The locking unit 2 is a right-angled base, with a groove 5 at one end of the base, a ratchet shaft 8 arranged in the groove 5, both ends of the ratchet shaft 8 passing through the base, a ratchet 9 fixed to one end of the ratchet shaft 8, a needle base 13 arranged on the base above the ratchet 9, the needle base 13 fixed to the base, a needle shaft 12 arranged on the needle base 13, a needle 11 arranged at the end of the needle shaft 12, the needle 11 meshing with the ratchet 9; two wire sleeves 15 are arranged at intervals on the ratchet shaft 8 in the groove, a wire shaft 14 parallel to the ratchet shaft 8 is arranged at the front lower part of the ratchet shaft 8, a fine adjustment sheet 7 is arranged on the bottom of the groove 5 in front of the wire shaft 14 , vertically arranged guide shafts 6 are respectively provided at both ends of the fine adjustment piece 7, and the guide shaft 6 passes through the fine adjustment piece 7. A threaded hole is provided in the middle of the fine adjustment piece 7 between the two guide shafts 6, and the fine adjustment bolt 4 penetrates into the groove 5 from the base at the top of the groove 5 and is connected with the threaded hole on the fine adjustment piece 7 and passes through the base at the bottom of the groove 5; the fastening steel wire 3 is respectively wound around the wire sleeve 15, and the end of the fastening steel wire 3 is led out from the wire sleeve 15 to bypass the bottom of the wire shaft 14, and passes through the gap between the wire shaft 15 and the fine adjustment piece 7, and passes through the groove 5 from the upper surface of the fine adjustment piece 7, and is connected to the wire fastening hole on the other end of the base of the adjacent locking unit 2 through a fastening bolt.

[0038] The base body is provided with a magnet groove on the inner side at a right angle, and a magnet 16 is embedded in the magnet groove. The magnetic force of the magnet is used to preliminarily fix the test piece 1 arranged on the locking mechanism.

[0039] The end face of the ratchet rotating shaft 8, which is provided with the ratchet 9, is designed as a hexagon 10, so as to facilitate tightening with a tool.

[0040] The method for measuring and calculating inertia parameters using the above-mentioned excitation auxiliary device based on the modal test mass line includes the following steps:

[0041] 1) Place the excitation auxiliary device on the workbench, set the two ends of the test piece on the locking mechanism, and use the magnet in the base to preliminarily fix the position of the test piece;

[0042] 2) Lead the fastening steel wire out of the steel wire sleeve, pass around the bottom of the wire shaft, pass through the gap between the wire shaft and the fine adjustment piece, pass through the groove on the upper surface of the fine adjustment piece, and connect with the steel wire fastening hole on the other end of the adjacent locking unit base through the fastening bolt and tighten;

[0043] 3) After determining the length of the tightening wire, twist the ratchet shaft to preliminarily tighten the wire rope; after the preliminarily tightening, twist the fine adjustment bolt to raise the fine adjustment piece and tighten the wire rope. During this process, use a force hammer to knock the excitation auxiliary device to check the tightness. After the tightening conditions are met, stop twisting the fine adjustment bolt to complete the tightening of the test piece. Use the modal hammer method to knock the corner points at the right angles of the auxiliary device to ensure at least 2 knocks in the XYZ direction, obtain the frequency response function of the test piece, and calculate the inertia parameters of the entire system (including the excitation auxiliary device) according to the mass line algorithm;

[0044] 4) Determine the mass m of the excitation auxiliary device 0 and the moment of inertia of a point in the matrix of the relative excitation auxiliary device and product of inertia This point is defined as the reference point. The excitation devices are arranged in pairs in a symmetrical manner. The excitation devices are arranged at the outermost side of a certain direction of the coordinate axis of the test piece to excite the sixth-order rigid body mode of the entire system.

[0045] 5) After the device is arranged, measure the response coordinates of the sensor and the coordinates of the hammer excitation, and at the same time measure the coordinates of the reference point in the reference coordinate system of the test piece (x 0 y 0 z 0 ), calculate the inertia parameters of the entire system according to the test results of the mass line and the calculation method of the following formula (1) and formula (2):

[0046]

[0047] In formula (1), the excitation force F applied at a point i on the rigid body to be measured is i =(f ix f iy f iz ), F i Angular acceleration of the object under test under excitation, (x c y c z c ) is the center of mass of the test system, is the acceleration of point j relative to the reference point O, m a is the total mass of the test system (the test piece and the excitation auxiliary device);

[0048]

[0049] In formula (2), (x Ji y Ji z Ji ) is the coordinate of the excitation point,

[0050] 6) Calculate the actual mass m of the test piece by using the following formulas (3), (4), (5) and (6): z , Inertia parameters of the test piece (J z xx J z yy J z zz ), product of inertia (J z yz J z xz J z xy ) Heat transfer centroid coordinates (x z c y z c z z c ):

[0051] m z =m a -m 0 (3)

[0052]

[0053]

[0054]

[0055] The center of mass position is determined by the mass distribution of the test piece. Since the excitation auxiliary devices are in pairs and symmetrically distributed, the influence on the center of mass can be ignored.

Claims

1. An excitation auxiliary device based on modal test quality line, characterized in that: It includes a pair of locking mechanisms, both ends of the test piece are arranged on the locking mechanisms, each locking mechanism includes 4 locking units, and the 4 locking units are connected by fastening wires to form a rectangular frame; The locking unit is a right-angled base with a groove at one end of the base. A ratchet rotating shaft is arranged in the groove. Both ends of the ratchet rotating shaft pass through the base. A ratchet is fixed to one end of the ratchet rotating shaft. A needle base is arranged on the base above the ratchet. The needle base is fixed to the base. A needle shaft is arranged on the needle base. A needle is arranged at the end of the needle shaft. The needle engages with the ratchet. Two wire sleeves are arranged at intervals on the ratchet rotating shaft in the groove. A wire shaft parallel to the ratchet rotating shaft is arranged at the front lower part of the ratchet rotating shaft. A fine adjustment sheet is arranged on the bottom of the groove in front of the wire shaft. A vertically arranged guide shaft is respectively arranged at both ends of the plate, and the guide shaft passes through the fine-precision adjustment plate. A threaded hole is arranged in the middle of the fine-precision adjustment plate between the two guide shafts, and a fine-adjustment bolt is passed from the base at the top of the groove into the groove, connected with the threaded hole on the fine-precision adjustment plate and passed through the base at the bottom of the groove; a fastening steel wire is respectively wound around the steel wire sleeve, and the end of the fastening steel wire is led out from the steel wire sleeve to bypass the bottom of the wire shaft, and passes through the gap between the wire shaft and the fine-precision adjustment plate, passes through the groove from the upper surface of the fine-precision adjustment plate, and is connected with the steel wire fastening hole on the other end of the adjacent locking unit base through a fastening bolt; The base body is provided with a magnet groove on the inner side at a right angle, and a magnet is embedded in the magnet groove, and the magnetic force of the magnet is used to preliminarily fix the test piece arranged on the locking mechanism; The ratchet rotating shaft has an end surface at one end of the ratchet which is designed to be hexagonal.

2. The method for measuring and calculating inertia parameters using the excitation auxiliary device based on modal test mass line according to claim 1 comprises the following steps: 1) Place the excitation auxiliary device on the workbench, set the two ends of the test piece on the locking mechanism, and use the magnet in the base to preliminarily fix the position of the test piece; 2) Lead the fastening steel wire out of the steel wire sleeve, pass around the bottom of the wire shaft, pass through the gap between the wire shaft and the fine adjustment piece, pass through the groove on the upper surface of the fine adjustment piece, and connect with the steel wire fastening hole on the other end of the adjacent locking unit base through the fastening bolt and tighten; 3) After determining the length of the tightening wire, twist the ratchet shaft to preliminarily tighten the wire rope; after the preliminarily tightening, twist the fine adjustment bolt to raise the fine adjustment piece and tighten the wire rope. During this process, use a force hammer to knock the excitation auxiliary device to check the tightness. After the tightening conditions are met, stop twisting the fine adjustment bolt to complete the tightening of the test piece. Use the modal hammer method to knock the corner points at the right angles of the auxiliary device to ensure at least 2 knocks in the XYZ direction, obtain the frequency response function of the test piece, and calculate the inertia parameters of the entire system (including the excitation auxiliary device) according to the mass line algorithm; 4) Determine the mass m of the excitation auxiliary device 0 and the moment of inertia of a point in the base of the relative excitation auxiliary device and product of inertia This point is defined as the reference point. The excitation devices are arranged in pairs in a symmetrical manner. The excitation devices are arranged at the outermost side of a certain direction of the coordinate axis of the test piece to excite the sixth-order rigid body mode of the entire system. 5) After the device is arranged, measure the response coordinates of the sensor and the coordinates of the hammer excitation, and at the same time measure the coordinates of the reference point in the reference coordinate system of the test piece (x 0 y 0 z 0 ), calculate the inertia parameters of the entire system according to the test results of the mass line and the calculation method of the following formula (1) and formula (2): In formula (1), the excitation force F applied at a point i on the rigid body to be measured is i =(f ix f iy f iz ), F i The angular acceleration of the object under test under the excitation force, (xc yc zc) is the center of mass of the test system, is the acceleration of point j relative to the reference point O, m a is the total mass of the test system (the test piece and the excitation auxiliary device); In formula (2), (x Ji y Ji z Ji ) is the coordinate of the excitation point, 6) Calculate the actual mass m of the test piece by using the following formulas (3), (4), (5) and (6): z , Inertia parameters of the test piece (J z xx J z yy J z zz ), product of inertia (J z yz J z xz J z xy ) Heat transfer centroid coordinates (x z c y z c z z c ): m z =m a -m 0 (3) The center of mass position is determined by the mass distribution of the test piece. Since the excitation auxiliary devices are in pairs and symmetrically distributed, the influence on the center of mass can be ignored.

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