CN114383776B - Method for improving aircraft gravity center measurement accuracy - Google Patents
Method for improving aircraft gravity center measurement accuracy Download PDFInfo
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- CN114383776B CN114383776B CN202111473277.2A CN202111473277A CN114383776B CN 114383776 B CN114383776 B CN 114383776B CN 202111473277 A CN202111473277 A CN 202111473277A CN 114383776 B CN114383776 B CN 114383776B
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- G01M1/00—Testing static or dynamic balance of machines or structures
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Abstract
A method of improving accuracy of aircraft center of gravity measurement, comprising the steps of: (1) placing an ultrathin memory material on a ground scale platform; (2) self-leveling and zero correction are carried out on the ground scale; (3) The aircraft is pulled to a ground scale platform, and the deflection angle of the wheels responsible for turning is zero degrees; (4) Mounting the digital display horizontal electronic ruler to a zero point of a longitudinal axis of the aircraft and other specified positions; (5) Judging the height of a plane where an airplane wheel is located, randomly selecting a plane where a floor scale is located as a reference, and adjusting the lifting mechanisms of other floor scales as a whole; (6) Acquiring a reading of the ground scale through a data processing mobile terminal to obtain the geometric figure center of gravity of the wheel indentation; (7) towing the aircraft off each ground scale; (8) Measuring the distance of the axis by a laser range finder, and inputting the measured distance data into a data processing mobile terminal; (9) And the data processing mobile terminal is used for carrying out centralized processing on the measurement data, and the position of the center of gravity of the airplane on the longitudinal axis is obtained through calculation.
Description
Technical Field
The invention belongs to the technical field of aircraft gravity center measurement; in particular to a method for improving the accuracy of the measurement of the center of gravity of an airplane
Background
The center of gravity of the aircraft is a hypothetical point at which the aircraft can remain balanced, provided that the weight of the aircraft is concentrated and supports the takeoff aircraft. The pitching, yawing and rolling three-way rotation of the aircraft are all carried out around the gravity center of the aircraft, and the gravity center of the aircraft is always changed due to the consumption of fuel oil, retraction of the landing gear and other factors. In actual weight balancing operations, the position of the center of gravity of an aircraft is typically expressed in% MAC (average aerodynamic chord length). The center of gravity of the aircraft is guaranteed to be in the design range, and the aircraft is one of key factors for guaranteeing the flight safety and the service life of the aircraft. The weight center of gravity measurement of the aircraft is a test verification relative to the theoretical center of gravity, is an important ground test of various types of aircraft before first flying, and the accuracy of the weight center of gravity measurement of the aircraft directly influences the flight safety of the aircraft. The traditional aircraft gravity center measuring method is that three aircraft wheels are pushed to three electronic scales on the ground, then an aircraft landing gear buffer (landing gear fixing clamp) is fixed on a landing gear to keep the aircraft landing gear in a full-extension state, the aircraft horizontal state is measured through a manual operation horizontal measuring instrument, and a cushion block is added under the aircraft wheels continuously by combining an aircraft jack to jack the aircraft, so that the aircraft is adjusted to the horizontal state. And then, carrying out the work of the whole aircraft, the air aircraft, the oil transportation sequence and the like, and carrying out the gravity center measurement on the whole aircraft process by combining an electronic scale and a horizontal measuring instrument. The conventional method can basically complete the measurement work of the center of gravity of the aircraft. However, when the compression amounts of the tires of the air-craft and the full-load air-craft are inconsistent, the deviation of the measurement result often occurs, that is, the traditional measurement method does not consider the compression amount of the tires of the air-craft, the wheel base measurement of the front and main machine wheels of the air-craft and the wheel base measurement have great errors; the horizontal measuring ruler generally uses a conventional optical theodolite to conduct reading measurement, human errors are large, the gravity center of the airplane is measured inaccurately, the production quality of the airplane cannot be guaranteed, and the flight safety of the airplane is affected seriously. And when measuring polytype aircraft focus, need to install undercarriage buffer (undercarriage fixed clamp) for the aircraft undercarriage, inefficiency, long consuming time, weighing process is complicated, and the operation is inconvenient, and the cost of labor is higher, basically all needs artifical participation, and human error is more phenomenon, has influenced aircraft production efficiency.
Disclosure of Invention
Aiming at the heavy demand of the prior art, the invention provides a method for improving the measurement accuracy of the center of gravity of the airplane, which can reduce the measurement workload of the center of gravity of the airplane, improve the measurement work efficiency of the center of gravity of the airplane and ensure the measurement accuracy of the center of gravity of the airplane.
A method of improving accuracy of aircraft center of gravity measurement, comprising the steps of:
(1) The ultrathin memory material is placed on a ground scale platform and can enable all the wheels to be pressed to the position, the ultrathin memory material can transmit signals to the data processing mobile terminal, can collect deformation contours caused by the pressure of the wheels, and is converted into image signals of the data processing mobile terminal through pressure signal conversion and voltage signal conversion;
(2) Leveling the floor scale and correcting zero position, wherein the lower end of the floor scale is provided with a lifting mechanism and a plurality of digital display horizontal electronic scales, the lifting mechanism has the functions of independent lifting and multiple combined lifting and locking, the horizontal condition of the floor scale is judged by reading the data of the digital display horizontal electronic scales, after the horizontal adjustment is finished, the lifting mechanism is locked, the floor scale is subjected to zero position adjustment through a data processing mobile terminal, and the data processing mobile terminal is communicated with the floor scale through wires or wirelessly;
(3) The aircraft is pulled to a ground balance platform corresponding to the aircraft wheel, and the deflection angle of the aircraft wheel responsible for turning is zero degrees;
(4) Mounting the digital display horizontal electronic ruler to a zero point of a longitudinal axis of the aircraft and other specified positions required by the design of the aircraft; the digital display horizontal electronic ruler is required to be installed in parallel with the plane of symmetry of the aircraft, and the aircraft design requirement refers to the point position to be measured when the aircraft weighing condition is met and the level is regulated;
(5) Judging the height of a plane where the airplane wheels are located through a digital display horizontal electronic ruler on the airplane, randomly selecting a plane where one ground scale is located as a reference, and adjusting the lifting mechanisms of other ground scales as a whole, wherein the horizontal adjustment process is based on the characteristics of an airplane model, the characteristics of the airplane model are that the plane where the airplane wheels are located is lifted by one unit height, and the lifting heights of the planes where the other airplane wheels are located correspond to one proportion;
(6) The method comprises the steps of processing image signals transmitted by an ultrathin memory material through readings acquired by a data processing mobile terminal to obtain the geometric figure center of gravity of a wheel trace, and feeding back the geometric figure center of gravity to the surface of the ultrathin memory material;
(7) Towing the aircraft away from each ground scale;
(8) Measuring the distance of an axis through a laser range finder, wherein the axis is a line which is perpendicular to the geometric figure of each machine wheel indentation and passes through the center of gravity of the geometric figure, and inputting measured distance data into a data processing mobile terminal;
(9) And the measured weight and distance data are processed in a centralized way through the data processing mobile terminal, and the position of the center of gravity of the airplane on the longitudinal axis is obtained by resolving according to the moment balance principle.
The invention has the following effective effects: in order to solve the problems of complicated measuring process, large calculating error and the like of the existing aircraft gravity center, the invention provides a method for improving the measuring accuracy of the aircraft gravity center, which comprises the following steps: the aircraft adjusting level and the weighing process can be realized without jacking the aircraft; the method is suitable for measuring the gravity centers of multi-tonnage aircrafts with different sizes; the airplane state is fixed without a clamp support; the wheel tread and wheel base measurement takes the compression deformation of the tire into account; accurate measurement of wheel tread, wheel base and weight is realized.
Drawings
FIG. 1 is a schematic view of a front three-point landing gear
Detailed Description
The technical scheme of the invention is further described below.
A method for improving the accuracy of aircraft center of gravity measurement, comprising the steps of:
(1) Selecting an ultrathin memory material with proper size, and flatly placing the ultrathin memory material on a floor scale platform to ensure that a machine wheel can be completely pressed on the surface of the ultrathin memory material;
furthermore, the ultrathin memory material can transmit signals to the data processing mobile terminal in a wireless or wired mode, the ultrathin memory material can acquire deformation profiles caused by the pressure of the wheels, no matter how many tires are arranged on each wheel, the deformation profiles are rectangular according to the existing aircraft wheel design, and the deformation profiles become image signals of the data processing mobile terminal through the conversion of pressure signals and voltage signals;
(2) Leveling the ground scale and correcting the zero position;
further, a lifting mechanism and a digital display horizontal electronic ruler are arranged at the lower end of the floor scale, and the lifting mechanism can be a mechanical hydraulic jack, an electric jack, a spring jack and the like;
furthermore, the lifting mechanism has the functions of independent lifting and multiple combined lifting and locking, the installation plane of the lifting mechanism is parallel to the upper plane of the floor scale platform, the number of the lifting mechanism is determined according to the weight of the aircraft, the number of the floor scales is not less than three, and the lifting mechanism used by each floor scale is not less than three, so that the adjustment process is safe and stable;
further, the digital display horizontal electronic ruler is arranged on the upper surface or the side surface of the floor scale platform so as to observe and read the data, the horizontal condition of the floor scale is judged by reading the data of the digital display horizontal electronic ruler, the lifting mechanism is gradually adjusted, the lifting mechanism is fully locked after the horizontal adjustment is finished, and the direction of the supporting force of the machine wheel on the floor scale is vertical to the plane where the floor scale platform is positioned by adjusting the horizontal of the floor scale;
furthermore, the data processing mobile terminal communicates with the floor scale through wires or wirelessly, and the floor scale is zeroed through the data processing mobile terminal;
(3) The aircraft is pulled to a ground balance platform corresponding to the aircraft wheel, and the deflection angle of the aircraft wheel responsible for turning is zero degrees;
further, the structural form of the landing gear of the airplane is divided into a front three-point type, a rear three-point type, a multi-point type and the like, and the required quantity and the placing positions of the floor scales are determined according to the structural form of the landing gear of the airplane;
(4) Mounting the digital display horizontal electronic ruler to a zero point of a longitudinal axis of the aircraft and other specified positions required by the design of the aircraft; the digital display horizontal electronic ruler is required to be installed in parallel with the plane of symmetry of the aircraft, and the aircraft design requirement refers to the point position to be measured when the aircraft weighing condition is met and the level is regulated;
furthermore, the measured point positions are a plurality of measuring points on the same side of the airplane body and a plurality of measuring points on the symmetrical positions of the wings, which are required to be measured according to the design of the airplane model;
(5) Judging the height of a plane where the airplane wheels are located through a digital display horizontal electronic ruler on the airplane, randomly selecting a plane where one ground scale is located as a reference, and adjusting the lifting mechanisms of other ground scales as a whole, wherein the horizontal adjustment process is based on the characteristics of an airplane model, the characteristics of the airplane model are that the plane where the airplane wheels are located is lifted by one unit height, and the lifting heights of the planes where the other airplane wheels are located correspond to one proportion;
further, the plane where one ground is randomly selected can be the highest plane, the lowest plane or the middle height plane;
furthermore, the lifting mechanism is integrally adjusted, so that the plane where each floor scale is located can be lifted simultaneously, and the lifting mechanism of the floor scale can be integrally adjusted to be a necessary function of the floor scale;
further, the aircraft digital-to-analog is characterized by: taking a previous three-point landing gear as an example, a unit height is adjusted on a plane where a front wheel floor scale is located, a main machine theory change corresponds to a specific height (such as 1:1, 1:2, 1:3 and the like), the change proportion is determined by aircraft design, and the main machine theory belongs to aircraft inherent parameters, and generally is as follows: 1, the aircraft can be adjusted to the left and right in the forward direction through proper adjustment;
further, the principle of adjusting the level of the rear three-point type is the same as that of the front three-point type;
furthermore, the multi-point type is basically the same as the front three-point type or the rear three-point type in the level adjustment principle, and the airplane wheel stations follow symmetrical distribution;
(6) The method comprises the steps of processing image signals transmitted by an ultrathin memory material through readings acquired by a data processing mobile terminal to obtain the geometric figure center of gravity of a wheel trace, and feeding back the geometric figure center of gravity to the surface of the ultrathin memory material;
further, the geometric figure center of gravity of the machine wheel indentation refers to the rectangular center of gravity formed on the surface of the ultrathin memory material, and the data processing mobile terminal can display the center of gravity on the surface of the ultrathin memory material in the form of bright spots;
further, taking a front three-point landing gear as an example, a front floor scale reading G1, a left floor scale reading G2, a right floor scale reading G3, wherein the total weight of the aircraft is G, a front floor scale indentation geometric gravity center A, a left floor scale indentation geometric gravity center B and a right floor scale indentation geometric gravity center C;
further, taking a rear three-point landing gear as an example, a rear floor scale reading G4, a front left floor scale reading G5, a front right floor scale reading G6, the total weight of the aircraft is G, a rear floor scale indentation geometric gravity center D, a front left floor scale indentation geometric gravity center E and a front right floor scale indentation geometric gravity center F;
further, taking a four-point landing gear as an example, a front left floor scale reading G7, a front right floor scale reading G8, a rear left floor scale reading G9, a rear right floor scale reading G10, the total weight of the aircraft is G, the geometrical center of indentation H of the front left floor scale, the geometrical center of indentation I of the front right floor scale, the geometrical center of indentation J of the rear left floor scale and the geometrical center of indentation K of the rear right floor scale are all taken as the examples;
(7) Towing the aircraft away from each ground scale;
(8) Measuring the distance of an axis through a laser range finder, wherein the axis is a line which is perpendicular to the geometric figure of each machine wheel indentation and passes through the center of gravity of the geometric figure, and inputting measured distance data into a data processing mobile terminal;
further, the laser range finder is randomly horizontally arranged at any indentation geometric gravity center position (A, B, C or D), a reference object with proper length is arranged at other geometric gravity center positions, the reference object is perpendicular to the plane of the floor scale, and the reference object is equivalent to the axis;
further, taking the previous three-point landing gear as an example, the distances of the three geometric centers of gravity may be expressed as ab=l1, ac=l2, bc=l3;
further, taking the three-point landing gear as an example, the distances of the three geometric centers of gravity may be expressed as de=l4, df=l5, and ef=l6;
further, taking a four-point landing gear as an example, the distances of the four geometric centers of gravity may be expressed as hi=l7, hj=l8, ik=l9, jk=l10;
(9) And the measured weight and distance data are processed in a centralized way through the data processing mobile terminal, and the position of the center of gravity of the airplane on the longitudinal axis is obtained by resolving according to the moment balance principle.
Further, taking the previous three-point landing gear as an example, the point of the projection of the gravity center of the aircraft on the plane of the ground platform along the axis direction of the aircraft is O, the projection of the zero point of the longitudinal axis of the aircraft on the plane of the ground platform is X, and the axial distances ox=l, oa=l11, oc=l12 and ac=l2 passing through the projection O point, the X point, the a point, the B point and the C point respectively and being perpendicular to the plane of the ground platform;
further, in the plane triangle OAC, the cosine law formula is used to obtain
Cos∟AOC=(L 2 11+L 2 2-L 2 12)/2*L11*L2
Further, by O 0 Is a moment fulcrum, is obtained by a moment balance principle, calculates L,
g1+g2+g3, l= (g1×l7+ (g2+g3) ×l5) ×cos master AOC/G, wherein the landing gear compression caused by the difference between the left and right floor readings G2, G3 has been ignored due to the symmetrical design of the aircraft, see fig. 1;
further, the results are substantially similar for the three-point landing gear example and for the four-point landing gear example.
Claims (1)
1. A method for improving the accuracy of aircraft center of gravity measurement, comprising the steps of:
(1) The ultrathin memory material is placed on a ground scale platform and can enable all the wheels to be pressed to the position, the ultrathin memory material can transmit signals to the data processing mobile terminal, can collect deformation contours caused by the pressure of the wheels, and is converted into image signals of the data processing mobile terminal through pressure signal conversion and voltage signal conversion;
(2) Leveling the floor scale and correcting zero position, wherein a lifting mechanism and a digital display horizontal electronic ruler are arranged at the lower end of the floor scale, the lifting mechanism has the functions of independent lifting and multiple combined lifting and locking, the horizontal condition of the floor scale is judged by reading the data of the digital display horizontal electronic ruler, after the horizontal adjustment is finished, the lifting mechanism is locked, the floor scale is adjusted to zero position through a data processing mobile terminal, and the data processing mobile terminal communicates with the floor scale through wires or wirelessly;
(3) The aircraft is pulled to a ground scale platform corresponding to the aircraft wheel, and the deflection angle of the aircraft wheel responsible for turning is zero degrees;
(4) Mounting the digital display horizontal electronic ruler to a zero point of a longitudinal axis of the aircraft and other specified positions required by the design of the aircraft; the digital display horizontal electronic ruler is required to be installed in parallel with the plane of symmetry of the aircraft, and the aircraft design requirement refers to the point position to be measured when the aircraft weighing condition is met and the level is regulated;
(5) Judging the height of a plane where the wheels of the airplane are located through a digital display horizontal electronic ruler on the airplane, randomly selecting the plane where one floor scale is located as a reference, and adjusting the lifting mechanisms of other floor scales as a whole, wherein the horizontal adjustment process is based on the characteristics of an airplane model, the characteristics of the airplane model are that the plane where the wheels are located is lifted by one unit height, and the lifting heights of the planes where the other wheels are located correspond to one proportion;
(6) The data processing mobile terminal is used for collecting the reading of the floor scale, processing the image signal transmitted by the ultrathin memory material to obtain the geometric figure center of gravity of the wheel trace, and feeding back to the surface of the ultrathin memory material;
(7) Towing the aircraft off each floor scale;
(8) Measuring the distance of an axis through a laser range finder, wherein the axis is a line which is perpendicular to the geometric figure of each machine wheel indentation and passes through the center of gravity of the geometric figure, and inputting measured distance data into a data processing mobile terminal;
(9) And the measured weight and distance data are processed in a centralized way through the data processing mobile terminal, and the position of the center of gravity of the airplane on the longitudinal axis is obtained by resolving according to the moment balance principle.
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| US20080046168A1 (en) * | 2006-07-18 | 2008-02-21 | Mccarthy Dennis K | System and method for determining an aircraft center of gravity |
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