CN109115513B - Method for determining natural frequency of moving frame of six-component test bed - Google Patents
Method for determining natural frequency of moving frame of six-component test bed Download PDFInfo
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- CN109115513B CN109115513B CN201811163643.2A CN201811163643A CN109115513B CN 109115513 B CN109115513 B CN 109115513B CN 201811163643 A CN201811163643 A CN 201811163643A CN 109115513 B CN109115513 B CN 109115513B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M15/00—Testing of engines
- G01M15/14—Testing gas-turbine engines or jet-propulsion engines
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/12—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring axial thrust in a rotary shaft, e.g. of propulsion plants
Abstract
A method for determining the natural frequency of a movable frame of a six-component test bed comprises the steps that the six-component test bed comprises the movable frame, a fixed frame and a force measuring assembly, wherein a test piece is fixedly arranged on the movable frame; in the main thrust direction, the movable frame is connected with the fixed frame through one force measuring assembly, in the horizontal force direction, the movable frame is connected with the fixed frame through two force measuring assemblies, and in the vertical force direction, the movable frame is connected with the fixed frame through three force measuring assemblies; the natural frequency of the movable frame comprises a main thrust direction natural frequency, a horizontal force direction natural frequency and a vertical force direction natural frequency. The method for determining the natural frequency of the movable frame of the six-component test bed realizes measurement of the six-component vector force, has a simple structure, and simultaneously accurately determines the natural frequency of the movable frame through stress analysis of the movable frame so as to conveniently remove the influence of the movable frame frequency in the subsequent test data processing process and improve the test accuracy.
Description
Technical Field
The invention relates to the technical field of thrust measurement, in particular to a method for determining natural frequency of a moving frame of a six-component test bed
Background
The engine test and test technology is an important component of the solid propulsion technology, and the thrust vector eccentricity is an important parameter to be measured in the engine test and test. To study engine thrust vector eccentricity requires extensive trial and error, which is not possible if all are put into flight testing. The main reasons are high flight test cost, long period, small information yield, risk and large manpower consumption. The engine ground test is to perform static test on the system according to specific conditions and environmental requirements on the ground to obtain various performance index information describing the system so as to solve the key problem in the thrust eccentricity test process of the engine, however, in the six-component test bed test process, the frequency of the movable frame is not determined by a mature technology, so that the test result is affected by the frequency of the movable frame, and the test is inaccurate.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the method overcomes the defects of the prior art and provides the method for determining the natural frequency of the movable frame of the six-component test bed.
The technical solution of the invention is as follows: a method for determining the natural frequency of a movable frame of a six-component test bed comprises the steps that the six-component test bed comprises the movable frame, a fixed frame and a force measuring assembly, wherein a test piece is fixedly arranged on the movable frame; in the main thrust direction, the movable frame is connected with the fixed frame through one force measuring assembly, in the horizontal force direction, the movable frame is connected with the fixed frame through two force measuring assemblies, and in the vertical force direction, the movable frame is connected with the fixed frame through three force measuring assemblies; the natural frequency of the moving frame comprises a main thrust direction natural frequency, a horizontal force direction natural frequency and a vertical force direction natural frequency, and the main thrust direction natural frequency, the horizontal force direction natural frequency and the vertical force direction natural frequency are determined by the following formulas:
in the formula: f. ofxThe natural frequency of the main thrust direction is in Hz; f. ofyIs the natural frequency in the horizontal force direction, and the unit is Hz; f. ofzIs the natural frequency in the vertical force direction, and the unit is Hz; k is the axial stiffness of a single force measuring component, the unit is N/m, and the K is a known quantity; and m is the sum of the masses of the movable frame and the test piece, the unit is kg, and the m is a known quantity.
Further, the movable frame comprises a switching frame, a central frame, a reinforcing plate and a truss; along the axial direction of the test piece, the switching frame, the truss and the center frame are fixedly connected in sequence, and the reinforcing plate is arranged on the test piece; the adapter rack comprises a front plate, a bearing pipe and a rear plate which are fixedly connected in sequence, the rear plate is connected with the truss, and a center sleeve is fixed on the front plate; the fixed frame comprises a horizontal base part, a bearing part and an installation part; the horizontal base part comprises a horizontal base, a horizontal base plate, a first supporting seat and a second supporting seat; the horizontal base plate is fixed on the horizontal base, the first supporting seat and the second supporting seat are fixed on the horizontal base, the number of the first supporting seats is 2, the first supporting seats are symmetrically arranged relative to the length direction of the horizontal base plate, and the number of the second supporting seats is 2, and the second supporting seats are symmetrically arranged relative to the length direction of the horizontal base plate; the bearing part comprises a bearing wall, a bearing frame, a bearing seat mounting seat and a bearing seat; the bearing wall is fixedly connected with one end of the horizontal base, one end of the bearing seat mounting seat is fixedly connected with the horizontal base plate, the other end of the bearing seat mounting seat is fixedly connected with the bearing seat, one end of the bearing frame is fixedly connected with the bearing wall, and the other end of the bearing frame is fixedly connected with the bearing seat; the mounting part comprises a first portal frame and a second portal frame, the first portal frame is fixedly connected with the first supporting seat, and the second portal frame is fixedly connected with the second supporting seat; the bearing wall, the bearing frame, the bearing seat, the first portal frame and the second portal frame are sequentially arranged along the length direction of the horizontal base.
Furthermore, the six-component test bed comprises a plurality of in-situ calibration devices, and a center sleeve on the adapter bracket is connected with the force bearing seat through a force measuring assembly; the top of the back plate is connected with a beam of the first portal frame through an in-situ calibration device, one side surface of the back plate is connected with one upright post of the first portal frame through a force measuring assembly, and the other side surface of the back plate is connected with the other upright post of the first portal frame through an in-situ calibration device; the bottom of the back plate is connected with the horizontal base plate through a force measuring assembly, and all the in-situ calibration devices and the force measuring assemblies connected with the back plate are arranged on a vertical surface; one side surface of the center frame is connected with one upright post of the second portal frame through one force measuring component, the other side surface of the center frame is connected with the other upright post of the second portal frame through one in-situ calibration device, the bottom of the center frame is connected with the horizontal base plate through 2 force measuring components and 1 in-situ calibration device, the 2 force measuring components connecting the bottom of the center frame and the horizontal base plate are positioned at two sides of the in-situ calibration device connecting the bottom of the center frame and the horizontal base plate, and all the in-situ calibration devices and the force measuring components connected with the center frame are positioned on one vertical surface.
Furthermore, the force measuring assembly comprises a first connecting plate, a first universal flexible part, a force measuring sensor, a second universal flexible part and a second connecting plate which are sequentially connected.
Furthermore, the in-situ calibration device comprises a hydraulic loading device, a force sensor and a calibration hydraulic cylinder which are connected in sequence.
Furthermore, a force measuring sensor of the force measuring assembly for connecting the central sleeve on the adapter frame with the force bearing seat is a pressure sensor.
Furthermore, the force measuring assembly connecting one side surface of the center frame with one upright post of the second portal frame and the force measuring sensor connecting one side surface of the back plate with one upright post of the first portal frame are tension and compression bidirectional force measuring sensors.
Furthermore, the force measuring sensors of the 2 force measuring assemblies connecting the bottom of the center frame and the horizontal base plate and the force measuring assemblies connecting the bottom of the rear plate and the horizontal base plate are tension-compression bidirectional force measuring sensors.
Furthermore, the front plate is connected with the force bearing seat through a pull rod, the bottom of the rear plate is connected with the horizontal base plate through 2 limiting support frames, and the 2 limiting support frames are located at the bottom of the rear plate and on two sides of the force measuring assembly of the horizontal base plate.
Furthermore, overflowing holes are formed in the first portal frame, the second portal frame and the bearing seat mounting seat.
Compared with the prior art, the invention has the advantages that:
1. the method for determining the natural frequency of the movable frame of the six-component test bed realizes measurement of the six-component vector force, has a simple structure, and simultaneously accurately determines the natural frequency of the movable frame through stress analysis of the movable frame so as to conveniently remove the influence of the movable frame frequency in the subsequent test data processing process and improve the test accuracy.
2. The invention relates to a method for determining the natural frequency of a moving frame of a six-component test bed, which is characterized in that the moving frame is rigidly connected with a test piece through a rear plate of a switching frame, a central frame supports and fixes the tail part of the test piece, an adjusting wheel adjusts the installation position of the test piece to enable the test piece to be coaxial with the moving frame so as to accurately position the test piece, a measuring device is connected with an in-situ calibration device through a central sleeve, the coaxiality of the test piece, a force measuring device and the in-situ calibration device is realized, the structure is simple, and the installation of the measuring device and the test piece is simple and easy.
3. The invention relates to a method for determining the natural frequency of a six-component test bed moving frame, which has larger overall rigidity of the moving frame, reasonably distributes stress elements on the design in order to ensure the dynamic performance of the test frame, adopts the principle of equal strength of the structure, removes the stress-free parts of materials and other optimization designs, and lightens the mass of the moving frame.
4. The invention discloses a method for determining the natural frequency of a moving frame of a six-component test bed, and relates to a six-component test bed.
5. The invention discloses a method for determining natural frequency of a moving frame of a six-component test bed, which relates to the six-component test bed.
6. The fixed frame of the six-component test bed is provided with the horizontal base, so that the bearing capacity of the whole fixed frame is improved, the horizontal base plate is fixedly arranged on the horizontal base through the pressing plate, the bearing capacity of the horizontal base plate is improved, and meanwhile, the levelness of the horizontal base plate is adjusted through adjusting the sizing block, so that the precision of the whole fixed frame is improved.
7. The invention discloses a method for determining the natural frequency of a movable frame of a six-component test bed, and relates to a six-component test bed.
Drawings
Fig. 1 is a schematic structural diagram of a six-component test bed according to a method for determining a natural frequency of a moving frame of a six-component test bed according to the present invention.
Fig. 2 is a schematic structural diagram of a fixed frame of a six-component test bed according to the method for determining the natural frequency of the fixed frame of the six-component test bed of the present invention.
Fig. 3 is a schematic structural diagram of a moving frame of a six-component test bed according to the method for determining the natural frequency of the moving frame of the six-component test bed of the present invention.
Fig. 4 is a schematic structural diagram of an adapter of a moving frame of a six-component test bed according to the method for determining the natural frequency of the moving frame of the six-component test bed of the present invention.
Fig. 5 is a schematic structural view of a center frame of a moving frame of a six-component test bed according to the method for determining a natural frequency of a moving frame of a six-component test bed of the present invention.
Fig. 6 is a schematic structural view of a reinforcing plate of a moving frame of a six-component test bed according to the method for determining a natural frequency of a moving frame of a six-component test bed of the present invention.
Fig. 7 is a schematic structural view of a force measuring unit of a six-component test bed according to the method for determining the natural frequency of the movable frame of the six-component test bed of the present invention.
Fig. 8 is a schematic structural diagram of a limiting support frame of a six-component test bed according to the method for determining the natural frequency of a moving frame of the six-component test bed of the present invention.
Fig. 9 is a mathematical model diagram illustrating a method for measuring vector thrust by six-component force of a six-component test bed according to a method for determining natural frequency of a movable frame of the six-component test bed of the present invention.
Detailed Description
In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted", "connected" and "abutted" are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
A method for determining the natural frequency of a moving frame of a six-component test bed for measuring the vector force of a test piece 10 comprises the moving frame 100, a fixed frame 200, a force measuring assembly 300 and an in-situ calibration device 400.
The movable frame 100 is a device for supporting the test piece 10 and transmitting the axial thrust, the horizontal lateral thrust and the vertical lateral force generated by the test piece, and has a length of about 3200mm, a circumferential dimension of about 900mm × 900mm and a weight of about 500 kg; specifically, the frame comprises an adapter frame 110, a center frame 120, a reinforcing plate 130 and a truss 140; the adapter frame 110, the truss 140 and the center frame 120 are sequentially fixedly connected along the axial direction of the test piece 10, and the reinforcing plate 130 is mounted on the test piece 10. The adapter frame 110 is a part for connecting the test piece 10 with the measuring device, and comprises a front plate 112, a bearing pipe 113 and a rear plate 114 which are fixedly connected in sequence, wherein the rear plate 114 is connected with the truss 140. A central sleeve 111 is fixed on the front plate 112; the front plate 112 is connected with the bearing seat 224 through a pull rod 225; the bottom of the rear plate 114 is connected with the horizontal base plate 212 through 2 limit support frames 370, and the 2 limit support frames 370 are positioned at two sides of the force measuring assembly 300 connecting the bottom of the rear plate 114 and the horizontal base plate 212.
The fixed frame 200 is a reference platform of the whole six-component test run rack, bears main thrust and lateral force transmitted by the force measuring assembly during working, bears standard force generated by the calibration oil cylinder assembly during calibration, and specifically comprises a horizontal base part, a force bearing part and an installation part; the horizontal base part comprises a horizontal base 211, a horizontal base plate 212, a first supporting seat 213 and a second supporting seat 214; horizontal base plate 212 is fixed on horizontal base 211, first supporting seat 213 and second supporting seat 214 are fixed on horizontal base 211, first supporting seat 213 is 2, for horizontal base plate 212 length direction symmetry sets up, second supporting seat 214 is 2, for horizontal base plate 212 length direction symmetry sets up. The bearing part comprises a bearing wall 221, a bearing frame 222, a bearing seat mounting seat 223 and a bearing seat 224; the bearing wall 221 is fixedly connected with one end of the horizontal base 211, one end of the bearing seat mounting seat 223 is fixedly connected with the horizontal base plate 212, the other end of the bearing seat mounting seat is fixedly connected with the bearing seat 224, one end of the bearing frame 222 is fixedly connected with the bearing wall 221, and the other end of the bearing frame is fixedly connected with the bearing seat 224; the force bearing seat 224 directly bears the axial thrust generated by the test piece and transmits the thrust to the force bearing wall 221 through the force bearing frame 222. The mounting portion includes a first portal frame 231 and a second portal frame 232, which are components for bearing and supporting the horizontal lateral force calibration device and the vertical lateral force calibration device, the first portal frame 231 is fixedly connected with the first support seat 213, and the second portal frame 232 is fixedly connected with the second support seat 214. Along the length direction of the horizontal base 211, the bearing wall 221, the bearing frame 222, the bearing seat 224, the first portal frame 231 and the second portal frame 232 are arranged in sequence.
The force measuring assembly 300 and the in-situ calibration device 400 are multiple; the movable frame 100 is connected with the fixed frame 200 through a plurality of force measuring assemblies 300 and a plurality of in-situ calibration devices 400; wherein, the central sleeve 111 on the adapter 110 is connected with the force bearing seat 224 through a force measuring assembly 300; the top of the rear plate 114 is connected with a beam of the first gantry 231 through an in-situ calibration device 400, one side surface of the rear plate 114 is connected with one upright of the first gantry 231 through a force measuring assembly 300, and the other side surface of the rear plate is connected with the other upright of the first gantry 231 through an in-situ calibration device 400; the bottom of the back plate 114 is connected to the horizontal base plate 212 through a load cell 300, and all the in-situ calibration devices 400 and the load cell 300 connected to the back plate 114 are on a vertical plane. One side surface of the center frame 120 is connected with one upright of the second portal frame 232 through one force measuring assembly 300, the other side surface of the center frame is connected with the other upright of the second portal frame 232 through one in-situ calibration device 400, the bottom of the center frame 120 is connected with the horizontal base plate 212 through 2 force measuring assemblies 300 and 1 in-situ calibration device 400, and the 2 force measuring assemblies 300 connected with the bottom of the center frame 120 and the horizontal base plate 212 are positioned at two sides of the in-situ calibration device 400 connected with the bottom of the center frame 120 and the horizontal base plate 212; all of the in-situ calibration device 400 and the load cell assembly 300 connected to the center frame 120 are on a vertical plane.
Taking a vertical plane where the axis of the test piece and all the in-situ calibration devices and the force measuring assemblies connected with the rear plate are located as a coordinate system origin O, taking the axis of the test piece as an X axis, enabling a Y axis to pass through the origin O to be vertically intersected with the X axis and to be parallel to a horizontal plane, and enabling a Z axis to pass through the origin O to be vertically intersected with the X axis and to be parallel to the vertical plane; wherein, the X-axis direction is a main thrust direction, the Y-axis direction is a horizontal force direction, and the Z-axis direction is a vertical force direction; the natural frequency of the moving frame comprises a main thrust direction natural frequency, a horizontal force direction natural frequency and a vertical force direction natural frequency, and the main thrust direction natural frequency, the horizontal force direction natural frequency and the vertical force direction natural frequency are determined by the following formulas:
in the formula: f. ofxThe natural frequency of the main thrust direction is in Hz; f. ofyIs the natural frequency in the horizontal force direction, and the unit is Hz; f. ofzIs the natural frequency in the vertical force direction, and the unit is Hz; k is the axial stiffness of the individual force-measuring assemblies inN/m, a known amount; and m is the sum of the masses of the movable frame and the test piece, the unit is kg, and the m is a known quantity.
Preferably, the force measuring assembly 300 comprises a first connecting plate 340, a first gimbal flexure 320, a force measuring sensor 310, a second gimbal flexure 330 and a second connecting plate 350, which are connected in sequence. Further preferably, the force measuring sensor of the force measuring assembly connecting the center sleeve 111 on the adapter 110 and the force bearing seat 224 is a pressure sensor; the force measuring component connecting one side surface of the center frame 120 with one upright of the second portal frame 232 and the force measuring sensor connecting one side surface of the rear plate 114 with one upright of the first portal frame 231 are tension and compression bidirectional force measuring sensors; the 2 load cells connecting the bottom of the center frame 120 to the horizontal base plate 212 and the load cells connecting the bottom of the rear plate 114 to the horizontal base plate 212 are pull-press bi-directional load cells.
Preferably, the in-situ calibration device 400 includes a hydraulic loading device 410, a force sensor 420 and a calibration hydraulic cylinder 430, which are connected in sequence, wherein the hydraulic loading device is a device for controlling the calibration hydraulic cylinder 430, and is composed of a stepping motor, a speed reducer, a plunger assembly and the like; the calibration oil cylinder is a force source of the in-situ calibration system, and applies force to the standard sensor. The in-situ calibration of the test piece of the test bed is realized by arranging the in-situ calibration device 400, the precision of the whole test bed is improved, and the precision error caused by the displacement of related test pieces after multiple tests is avoided.
Preferably, each upright of the first portal frame 231 is provided with a first portal mounting frame 234, each upright of the second portal frame 232 is provided with a second portal mounting frame 235, so as to realize the installation of the test piece simulation device, further preferably, the test piece 10 is a gas turbine engine or a gas turbine engine simulation test piece, when the test piece 10 is a gas turbine engine simulation test piece, the gas turbine engine simulation test piece includes a test piece simulation input cylinder 11, the test piece simulation input cylinders 11 are 4 and are respectively installed on the 2 first portal mounting frames 234 and the second portal mounting frames 235, and the test piece simulation input cylinder 11 is an air inlet simulation cylinder which simulates the air inlet of an engine. The fixed frame is skillfully installed by arranging the first gantry mounting frame and the second gantry mounting frame on the first gantry and the second gantry, so that the test piece simulation device is skillfully installed.
Preferably, the first portal frame 231, the second portal frame 232 and the force bearing seat mounting seat 223 are provided with overflowing holes 233 so as to reduce the influence of the surrounding flow field on the force measuring assembly.
Preferably, the number of the stress tubes 113 is 4, and the stress tubes are symmetrically arranged in the same plane relative to the axial direction of the test piece so as to reasonably distribute stress by adopting the principle of equal strength of the structure.
Preferably, the center frame 120 is a member for supporting and fixing the tail of the test piece, and includes an upper cover 121, a lower body 123 and an adjustment wheel 122; the upper cover 121 and the lower body 123 are fixedly connected, 4 adjusting wheels 122 are provided, 4 adjusting wheels 122 are symmetrically arranged in the same plane relative to the axial direction of the test piece 10, 2 adjusting wheels 122 penetrate through the upper cover 121, 2 adjusting wheels 122 penetrate through the lower body 123, and the mounting position of the test piece 10 is coaxially positioned with the movable frame by arranging the adjusting wheels.
Preferably, the reinforcing plate 130 is a component for bearing tens of tons of internal force generated by the test piece, and includes a flat plate 131 and adjusting brackets 132, the adjusting brackets 132 are fixed on the flat plate 131, the number of the reinforcing plates 130 is 2, the reinforcing plates are connected with the test piece 10 in a vertically symmetrical manner, and the adjusting brackets 132 include a test piece connecting plate 1321, a lifting adjusting device 1323 and an adjusting bracket fixing seat 1322; the two ends of the lifting adjusting device 1323 are respectively connected with the test piece connecting plate 1321 and the adjusting support fixing seat 1322, the lifting adjusting device 1323 can be in the form of a hydraulic cylinder, an air cylinder, a worm gear and the like, the test piece connecting plate 1321 is connected with the test piece 10, the adjusting support fixing seat 1322 is fixedly connected with the flat plate 131, and the height of the test piece connecting plate 1321 can be adjusted within a certain range by arranging the lifting adjusting device 1323, so that the connecting plate 1321 is ensured to be reliably contacted with the test piece 10, and a supporting effect is achieved. The truss 140 is composed of five horizontal support tubes and a plurality of groups of inclined support tubes, and is used for connecting the adapter frame 110 and the central frame 120, and simultaneously, the deformation caused by horizontal and lateral forces is borne, so that the rigidity of the movable frame is ensured.
Preferably, along the length direction of the horizontal base 211, 2T-shaped grooves 215 arranged in parallel are arranged on the horizontal base 211, the distance between the 2T-shaped grooves 215 is greater than the width of the horizontal base plate 212, a plurality of pressing plates 216 and adjusting sizing blocks 217 are arranged in the T-shaped grooves 215, and the horizontal base plate 212 is fixed on the horizontal base 211 through the plurality of pressing plates 216 and the levelness of the horizontal base plate is adjusted through the plurality of adjusting sizing blocks 217.
The first gantry 231 is higher than the second gantry 232.
Preferably, the flat plate 131 is provided with a bracket connection hole for connecting with the test piece 10 and ensuring the coaxiality of the test piece 10.
Preferably, the number of the adjusting brackets 132 is 2, and the adjusting brackets are arranged along the axial direction of the test piece 10, so as to further improve the coaxiality of the test piece 10.
The method for measuring the vector thrust by using the six-component test bed comprises the following steps:
s1), constructing a six-component force model;
an O-XYZ rectangular coordinate system is constructed, a vertical plane where the axis of the test piece and all the in-situ calibration devices and force measuring assemblies connected with the rear plate are located is taken as a coordinate system origin O, the axis of the test piece is taken as an X axis, a Y axis passes through the origin O and is vertically intersected with the X axis and is parallel to a horizontal plane, and a Z axis passes through the origin O and is vertically intersected with the X axis and is parallel to the vertical plane; the tension of the force measuring component is specified to be positive, and the compression is specified to be negative;
s2), according to the six-component force model, calculating the magnitude of vector thrust, the eccentric angle and the eccentric distance of the test piece through the solution of a space force system balance equation set; the space force system balance equation set is as follows:
in the formula: f1And F2The force measurement values of 2 force measurement assemblies connecting the bottom of the center frame and the horizontal base plate are respectively, and the unit is N; f3The unit of the force measurement value of the force measurement component for connecting one side surface of the central frame with one upright post of the second portal frame is N; f4The unit of the force measurement value of the force measurement component for connecting the bottom of the rear plate and the horizontal base plate is N; f5The unit of the force measurement value of the force measurement component for connecting one side surface of the back plate with one upright post of the first portal frame is N; f6The unit is N for the force measurement value of a force measurement component for connecting a center sleeve on the adapter bracket and a bearing seat;
p is the magnitude of vector thrust and the unit is N;
Px、Pyand PzThe components of vector thrust in X, Y, Z coordinate directions are respectively, and the unit of the quantity value is N;
Mx、My、Mzthe components of the resultant moment in X, Y, Z coordinate directions are respectively, the unit of the quantity value is N.m, and the positive direction is determined according to the right-hand spiral rule;
w is the gravity of the test piece in N, which is a known value;
Lmthe horizontal distance between the gravity center of the test piece and the vertical plane where all the in-situ calibration devices and the force measuring assemblies connected with the rear plate are located is a known value, and the unit is m;
l is the distance between the vertical surface where all the in-situ calibration devices and the force measuring assemblies connected with the back plate are located and the vertical surface where all the in-situ calibration devices and the force measuring assemblies connected with the center frame are located, the unit is m, and the unit is a known value;
r is half of the horizontal distance between the bottom of the center frame and 2 force measuring assemblies of the horizontal base plate on the vertical surface where all the in-situ calibration devices and the force measuring assemblies connected with the center frame are located, and the unit is m and is a known value;
ypand zpThe coordinates of the intersection point of the vector thrust passing through the vertical plane where the gravity center of the test piece is located on the Y axis and the Z axis respectively, and the numerical unit of the coordinates is m;
rho is the eccentricity of the vector thrust;
gamma is the eccentricity angle of the vector thrust.
The method of measuring vector thrust is based on the following conditions:
A. the test piece 10 is a rigid body;
B. the test piece 10 is an axially symmetric rotational body that is not deformed;
C. the gravity center of the test piece 10 is always positioned on the rotating shaft;
D. the lateral thrust of the test piece 10 is less than the main thrust;
E. the load cell is only subjected to forces acting in its axial direction, and is not subjected to forces acting in other directions and not reacted with them.
The method for measuring the vector thrust by the six-component test bed comprises the steps of constructing a six-component model, and solving the magnitude, the eccentric angle and the eccentric distance of the vector thrust of a tested object by a space force system balance equation group, so that a complex structure is simplified, and a foundation is laid for designing a six-component test system; the horizontal six-component force measuring method is different from the vertical six-component force measuring method in the prior art, a new design method is developed for a six-component force testing system, the design of the six-component force testing system is facilitated, and the problem that the existing vertical six-component force testing system occupies a large space is solved; in addition, the method for measuring the vector thrust by the six-component test bed fully considers the gravity of an engine, and greatly improves the measurement precision.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (9)
1. A method for determining the natural frequency of a movable frame of a six-component test bed is characterized in that the six-component test bed comprises a movable frame, a fixed frame and a force measuring assembly, wherein a test piece is fixedly arranged on the movable frame; in the main thrust direction, the movable frame is connected with the fixed frame through one force measuring assembly, in the horizontal force direction, the movable frame is connected with the fixed frame through two force measuring assemblies, and in the vertical force direction, the movable frame is connected with the fixed frame through three force measuring assemblies; the natural frequency of the moving frame comprises a main thrust direction natural frequency, a horizontal force direction natural frequency and a vertical force direction natural frequency, and the main thrust direction natural frequency, the horizontal force direction natural frequency and the vertical force direction natural frequency are determined by the following formulas:
in the formula: f. ofxThe natural frequency of the main thrust direction is in Hz; f. ofyIs the natural frequency in the horizontal force direction, and the unit is Hz; f. ofzIs the natural frequency in the vertical force direction, and the unit is Hz; k is the axial stiffness of a single force measuring component, the unit is N/m, and the K is a known quantity; m is the sum of the masses of the movable frame and the test piece, the unit is kg, and the m is a known quantity;
the movable frame comprises a switching frame, a central frame, a reinforcing plate and a truss; along the axial direction of the test piece, the switching frame, the truss and the center frame are fixedly connected in sequence, and the reinforcing plate is arranged on the test piece; the adapter rack comprises a front plate, a bearing pipe and a rear plate which are fixedly connected in sequence, the rear plate is connected with the truss, and a center sleeve is fixed on the front plate;
the fixed frame comprises a horizontal base part, a bearing part and an installation part; the horizontal base part comprises a horizontal base, a horizontal base plate, a first supporting seat and a second supporting seat; the horizontal base plate is fixed on the horizontal base, the first supporting seat and the second supporting seat are fixed on the horizontal base, the number of the first supporting seats is 2, the first supporting seats are symmetrically arranged relative to the length direction of the horizontal base plate, and the number of the second supporting seats is 2, and the second supporting seats are symmetrically arranged relative to the length direction of the horizontal base plate; the bearing part comprises a bearing wall, a bearing frame, a bearing seat mounting seat and a bearing seat; the bearing wall is fixedly connected with one end of the horizontal base, one end of the bearing seat mounting seat is fixedly connected with the horizontal base plate, the other end of the bearing seat mounting seat is fixedly connected with the bearing seat, one end of the bearing frame is fixedly connected with the bearing wall, and the other end of the bearing frame is fixedly connected with the bearing seat; the mounting part comprises a first portal frame and a second portal frame, the first portal frame is fixedly connected with the first supporting seat, and the second portal frame is fixedly connected with the second supporting seat; the bearing wall, the bearing frame, the bearing seat, the first portal frame and the second portal frame are sequentially arranged along the length direction of the horizontal base.
2. The method of claim 1, wherein: the six-component test bed comprises a plurality of in-situ calibration devices, and a center sleeve on the adapter bracket is connected with the force bearing seat through a force measuring assembly; the top of the back plate is connected with a beam of the first portal frame through an in-situ calibration device, one side surface of the back plate is connected with one upright post of the first portal frame through a force measuring assembly, and the other side surface of the back plate is connected with the other upright post of the first portal frame through an in-situ calibration device; the bottom of the back plate is connected with the horizontal base plate through a force measuring assembly, and all the in-situ calibration devices and the force measuring assemblies connected with the back plate are arranged on a vertical surface;
one side surface of the center frame is connected with one upright post of the second portal frame through one force measuring component, the other side surface of the center frame is connected with the other upright post of the second portal frame through one in-situ calibration device, the bottom of the center frame is connected with the horizontal base plate through 2 force measuring components and 1 in-situ calibration device, the 2 force measuring components connecting the bottom of the center frame and the horizontal base plate are positioned at two sides of the in-situ calibration device connecting the bottom of the center frame and the horizontal base plate, and all the in-situ calibration devices and the force measuring components connected with the center frame are positioned on one vertical surface.
3. The method of claim 1, wherein: the force measuring assembly comprises a first connecting plate, a first universal flexible part, a force measuring sensor, a second universal flexible part and a second connecting plate which are sequentially connected.
4. The method of claim 2, wherein: the in-situ calibration device comprises a hydraulic loading device, a force sensor and a calibration hydraulic cylinder which are sequentially connected.
5. The method of claim 2, wherein: the force measuring sensor of the force measuring component for connecting the central sleeve on the adapter bracket and the bearing seat is a pressure sensor.
6. The method of claim 2, wherein: and the force measuring assembly of one side surface of the connecting center frame and one upright post of the second portal frame and the force measuring sensor of the force measuring assembly of one side surface of the connecting back plate and one upright post of the first portal frame are tension and compression bidirectional force measuring sensors.
7. The method of claim 2, wherein: the force measuring sensors of the 2 force measuring assemblies connecting the bottom of the center frame and the horizontal base plate and the force measuring assemblies connecting the bottom of the rear plate and the horizontal base plate are tension-compression bidirectional force measuring sensors.
8. The method of claim 2, wherein: the front plate is connected with the force bearing seat through a pull rod, the bottom of the rear plate is connected with the horizontal base plate through 2 limiting support frames, and the 2 limiting support frames are located at the bottom of the rear plate and on two sides of the force measuring assembly of the horizontal base plate.
9. The method of claim 1, wherein: and overflowing holes are formed in the first portal frame, the second portal frame and the bearing seat mounting seat.
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| CN114777977B (en) * | 2022-04-11 | 2023-09-22 | 浙江蓝箭航天空间科技有限公司 | Counterforce measuring system and method for pipeline interface connected with rocket connector |
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