CN108928476B - Differential calculation method for pitch angle of helicopter - Google Patents
Differential calculation method for pitch angle of helicopter Download PDFInfo
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- CN108928476B CN108928476B CN201810678996.XA CN201810678996A CN108928476B CN 108928476 B CN108928476 B CN 108928476B CN 201810678996 A CN201810678996 A CN 201810678996A CN 108928476 B CN108928476 B CN 108928476B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C27/00—Rotorcraft; Rotors peculiar thereto
- B64C27/54—Mechanisms for controlling blade adjustment or movement relative to rotor head, e.g. lag-lead movement
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64F—GROUND OR AIRCRAFT-CARRIER-DECK INSTALLATIONS SPECIALLY ADAPTED FOR USE IN CONNECTION WITH AIRCRAFT; DESIGNING, MANUFACTURING, ASSEMBLING, CLEANING, MAINTAINING OR REPAIRING AIRCRAFT, NOT OTHERWISE PROVIDED FOR; HANDLING, TRANSPORTING, TESTING OR INSPECTING AIRCRAFT COMPONENTS, NOT OTHERWISE PROVIDED FOR
- B64F5/00—Designing, manufacturing, assembling, cleaning, maintaining or repairing aircraft, not otherwise provided for; Handling, transporting, testing or inspecting aircraft components, not otherwise provided for
- B64F5/60—Testing or inspecting aircraft components or systems
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Abstract
The invention relates to the field of helicopter pitch angle measurement, in particular to a differential calculation method for a helicopter pitch angle, which comprises the following steps: disposing a first angle sensor and a second angle sensor on the blade mounting surface a1 and the centerpiece plane B1, respectively; establishing a rectangular coordinate system, and establishing and simplifying a model; by controlling the three-axis rotation directions of the blade mounting surface A1 and the center piece plane B1 in the rectangular coordinate system X, Y, Z, the condition that the main rotor wing axis is not vertical is simulated, and the pitch angle of the corresponding condition is calculated. The differential calculation method for the pitch angle of the helicopter can realize the measurement of the pitch angle under the condition that the main rotor shaft is not perpendicular, has stable precision and high efficiency compared with the traditional method, and can also ensure the personal safety of measuring personnel and reduce the labor intensity.
Description
Technical Field
The invention relates to the field of helicopter pitch angle measurement, in particular to a differential calculation method for a helicopter pitch angle.
Background
After a helicopter flight control system installs or replaces components (such as a booster, a steering engine, and the like) on the helicopter, the system needs to be adjusted and checked to determine whether the position of a specific control device (a steering column, a collective lever, and a pedal) of the helicopter corresponds to a specific blade installation angle. Especially the blade mounting angle, the accuracy of the measurement is directly related to the flight performance and the flight quality of the helicopter.
Conventional blade setting angle measurements are typically made using a level gauge, by which the angle between the blade mounting surface at the root of the blade and the plane of the centerpiece is measured, while the helicopter main rotor shaft is "plumbed". According to the spatial geometrical knowledge, the included angle of the spatial plane is equal to the included angle of a straight line which is respectively positioned in two planes and is perpendicular to the intersection line of the two planes, the angle measured by the level is the included angle between the straight line and the horizontal plane, and on the basis, the measurement principle of the traditional method is that the angle of the straight line which is perpendicular to the intersection line on the blade installation surface, namely the pitch angle, is measured on the basis of ensuring the plane of the central component to be horizontal. The calculation needs to ensure that the plane of the central component is horizontal, and the central component needs to be vertical before measurement, so that the method has the disadvantages of multiple guarantee conditions, low efficiency and poor safety.
Disclosure of Invention
The invention aims to design a differential calculation method for a pitch angle of a helicopter, which is used for solving at least one problem existing in the existing blade installation angle measurement method.
The technical scheme of the invention is as follows:
a differential calculation method for a helicopter pitch angle comprises the following steps:
the method comprises the following steps of firstly, respectively arranging a first angle sensor and a second angle sensor on a blade mounting surface A1 and a centerpiece plane B1, wherein the X-axis direction of the first angle sensor and the X-axis direction of the second angle sensor are parallel to the axis of a blade, and the Y-axis of the first angle sensor and the Y-axis of the second angle sensor are in the same direction;
establishing a rectangular coordinate system, and establishing and simplifying a model according to the structural form of the step one, wherein the axis direction of the blade is the X-axis direction of the rectangular coordinate system, a straight line Y1 represents the Y-axis of the first angle sensor, the included angle between the straight line Y1 and the horizontal plane is alpha, a straight line Y2 represents the Y-axis of the second angle sensor, and the included angle between the straight line Y2 and the horizontal plane is beta;
thirdly, simulating the condition that the main rotor shaft is not vertical by controlling the three-axis rotation directions of the blade mounting surface A1 and the center piece plane B1 in the rectangular coordinate system X, Y, Z, and calculating the pitch angle of the corresponding condition, wherein the conditions comprise the following conditions:
when the blade mounting surface A1 and the center piece plane B1 rotate around the X axis of the rectangular coordinate system, the pitch angle theta is the included angle between the Y axis of the first angle sensor and the Y axis of the second angle sensor;
when the blade mounting surface A1 and the center piece plane B1 rotate around the Z axis of the rectangular coordinate system, the pitch angle theta is the included angle between the Y axis of the first angle sensor and the Y axis of the second angle sensor;
when the blade mounting surface a1 and the center piece plane B1 rotate around the Y axis of the rectangular coordinate system by an angle γ, the line Y1 'is the Y axis of the first rotated angle sensor, the angle between the line Y1' and the horizontal plane is α ', the line Y2' is the Y axis of the second rotated angle sensor, the angle between the line Y2 'and the horizontal plane is β', and the pitch angle θ is calculated according to the following formula (1):
optionally, in the third step, the formula (1) is obtained from the following formulas (2) and (3):
wherein, formula (2) is obtained from formula (4) and formula (5):
wherein R is the length from a predetermined point on the straight line Y1 to the perpendicular line of the XY surface of the rectangular coordinate system, and L is the length from a point on the straight line Y1' corresponding to the position of the predetermined point on the straight line Y1 to the perpendicular line of the XY surface of the rectangular coordinate system;
from equation (2), equation (3) can be derived in the same way.
The invention has the following effects:
the differential calculation method for the pitch angle of the helicopter can realize the measurement of the pitch angle under the condition that the main rotor shaft is not vertically drilled, has stable precision and high efficiency compared with the traditional method, can also ensure the personal safety of measuring personnel, and reduces the labor intensity.
Drawings
FIG. 1 is a simplified model of pitch angle measurement in the differential calculation method of the pitch angle of the helicopter of the present invention;
FIG. 2 is a main rotor shaft inclination model 1 in the differential calculation method of the pitch angle of the helicopter of the present invention;
FIG. 3 is a main rotor shaft inclination model 2 in the differential calculation method of the pitch angle of the helicopter of the present invention.
Detailed Description
In order to make the implementation objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the accompanying drawings in the embodiments of the present invention. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, but not all embodiments of the invention. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience in describing the present invention and for simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be taken as limiting the scope of the present invention.
The method for calculating the difference between the helicopter pitch angles according to the present invention will be described in further detail with reference to fig. 1 to 3.
The differential calculation method for the helicopter pitch angle respectively calculates the included angles between the plane of the central piece and the horizontal plane and between the blade mounting surface and the horizontal plane, and obtains the pitch angle by calculating the difference value of the two included angles. When the sensor is installed, the X axis is parallel to the axis of the blade, and the intersecting line of the plane of the central part and the blade installation surface is the axis of the blade, so that the pitch angle is converted into the included angle of the Y axis of the sensor. The data measured by the sensor is the included angle between the shaft and the horizontal plane, and when the main rotor shaft of the helicopter is not vertically drilled, the size of the pitch angle is not equal to the difference value of the angle of the Y shaft, and space calculation is needed.
Specifically, the differential calculation method for the pitch angle of the helicopter of the invention comprises the following steps:
the method comprises the following steps of firstly, respectively arranging a first angle sensor and a second angle sensor on a blade mounting surface A1 and a centerpiece plane B1, wherein the X-axis direction of the first angle sensor and the X-axis direction of the second angle sensor are parallel to the axis of a blade, and the Y-axis of the first angle sensor and the Y-axis of the second angle sensor are in the same direction.
And step two, establishing a rectangular coordinate system, and establishing and simplifying a model according to the structural form of the step one, wherein the axis direction of the blade is the X-axis direction of the rectangular coordinate system, a straight line Y1 represents the Y-axis of the first angle sensor, the included angle between the straight line Y1 and the horizontal plane is alpha, a straight line Y2 represents the Y-axis of the second angle sensor, and the included angle between the straight line Y2 and the horizontal plane is beta. As can be seen from the spatial geometry knowledge, the included angle theta between Y1 and Y2 is equal to the included angle between the A1 and B1 planes, namely the pitch angle.
Step three, the situation that the main rotor shaft is not vertically arranged can be represented as A, B surfaces rotating around the X, Y, Z shaft together; by controlling the three-axis rotation directions of the blade mounting surface A1 and the center piece plane B1 in the rectangular coordinate system X, Y, Z, the non-vertical condition of the main rotor shaft is simulated, and the pitch angle of the corresponding condition is calculated, including the following conditions:
when the blade mounting surface A1 and the center piece plane B1 rotate around the X axis of the rectangular coordinate system, the pitch angle theta is the included angle between the Y axis of the first angle sensor and the Y axis of the second angle sensor;
when the blade mounting surface A1 and the center piece plane B1 rotate around the Z axis of the rectangular coordinate system, the pitch angle theta is the included angle between the Y axis of the first angle sensor and the Y axis of the second angle sensor;
when the blade mounting surface a1 and the center piece plane B1 rotate by an angle γ around the Y-axis of the rectangular coordinate system, the straight line Y1 ' is the Y-axis of the first rotated angle sensor, the included angle between the straight line Y1 ' and the horizontal plane (XY plane) is α ', the straight line Y2 ' is the Y-axis of the second rotated angle sensor, the included angle between the straight line Y2 ' and the horizontal plane (XY plane) is β ', the straight lines Y1 and Y1 ' are located on a cone with the point O as a dot and the circle a as a bottom, and the pitch angle θ is calculated according to the following formula (1):
further, in the differential calculation method for the pitch angle of the helicopter of the present invention, the step three formula (1) is obtained by the following formula (2) and formula (3):
wherein, formula (2) is obtained from formula (4) and formula (5):
where R is the length from a predetermined point (i.e., an arbitrary point) on the straight line Y1 (before rotation) to the XY-plane perpendicular line of the rectangular coordinate system, and L is the length from a point on the straight line Y1' corresponding to the position of the predetermined point on the straight line Y1 to the XY-plane perpendicular line of the rectangular coordinate system.
From equation (2), equation (3) can be derived from the same reasoning, as follows:
when the radius of the circle A is R, the rotation angle of the A, B plane around the Y axis is gamma, and the rotated straight lines Y1 and Y2 are the straight lines Y1 'and Y2', the included angles between the straight lines Y1 'and Y2' and the horizontal plane (XY plane) are respectively alpha 'and beta'.
The straight lines Y1 and Y1' are located on a cone with O as a circle point and the circle a as a bottom, and the geometrical relationship shows that:
the two formulas are combined to obtain:
the radius of the circle B of the bottom surface of the cone rotated by the straight line Y2 around the Y axis is R ', the length from any point on the back line of the Y2 rotation gamma to the vertical line of the horizontal plane is L', and the geometrical relationship shows that:
the two formulas are combined to obtain:
from the expressions (2) and (3), the pitch angle θ is, in any case:
in a specific example of the method for calculating the difference of the pitch angle of the helicopter of the present invention:
alpha and beta are respectively 30 degrees and 45 degrees, namely the pitch angle is 15 degrees. When the A1 and B1 planes rotate 20 degrees around the Y axis, namely gamma is 20 degrees, alpha 'and beta' are 28.02 degrees and 41.64 degrees, the difference between alpha 'and beta' is 16.12 degrees, and the value is substituted into the formula to obtain the value of theta of 15.00 degrees.
The differential calculation method for the pitch angle of the helicopter can realize the measurement of the pitch angle under the condition that the main rotor shaft is not vertically drilled, has stable precision and high efficiency compared with the traditional method, can also ensure the personal safety of measuring personnel, and reduces the labor intensity.
The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Claims (2)
1. A method for calculating the difference of the pitch angle of a helicopter is characterized by comprising the following steps:
the method comprises the following steps of firstly, respectively arranging a first angle sensor and a second angle sensor on a blade mounting surface (A1) and a centerpiece plane (B1), wherein the X-axis direction of the first angle sensor and the X-axis direction of the second angle sensor are parallel to the axis of a blade, and the Y-axis of the first angle sensor and the Y-axis of the second angle sensor are in the same direction;
establishing a rectangular coordinate system, and establishing and simplifying a model according to the structural form of the step one, wherein the axis direction of the blade is the X-axis direction of the rectangular coordinate system, a straight line Y1 represents the Y-axis of the first angle sensor, the included angle between the straight line Y1 and the horizontal plane is alpha, a straight line Y2 represents the Y-axis of the second angle sensor, and the included angle between the straight line Y2 and the horizontal plane is beta;
thirdly, simulating the condition that the main rotor shaft is not vertical by controlling the three-axis rotation directions of the blade mounting surface (A1) and the center piece plane (B1) in the rectangular coordinate system X, Y, Z, and calculating the pitch angle of the corresponding condition, wherein the conditions comprise the following conditions:
a pitch angle θ is an angle between a Y-axis of the first angle sensor and a Y-axis of the second angle sensor when the blade mounting surface (A1) and a centerpiece plane (B1) are rotated about the X-axis of the rectangular coordinate system;
a pitch angle θ is an angle between a Y-axis of the first angle sensor and a Y-axis of the second angle sensor when the blade mounting surface (A1) and a centerpiece plane (B1) are rotated about a Z-axis of the rectangular coordinate system;
when the blade mounting surface (a1) and the centerpiece plane (B1) rotate around the Y axis of the rectangular coordinate system by an angle γ, the straight line Y1 'is the Y axis of the first rotated angle sensor, the included angle between the straight line Y1' and the horizontal plane is α ', the straight line Y2' is the Y axis of the second rotated angle sensor, the included angle between the straight line Y2 'and the horizontal plane is β', and the pitch angle θ is calculated according to the following formula (1):
2. a method of differential calculation of a helicopter pitch angle according to claim 1 wherein in said third step, equation (1) is derived from equations (2), 3) as follows:
wherein, formula (2) is obtained from formula (4) and formula (5):
wherein R is the length from a predetermined point on the straight line Y1 to the perpendicular line of the XY surface of the rectangular coordinate system, and L is the length from a point on the straight line Y1' corresponding to the position of the predetermined point on the straight line Y1 to the perpendicular line of the XY surface of the rectangular coordinate system;
from equation (2), equation (3) can be derived from the same reasoning, as follows:
the radius of the circle A is R, the rotation angle of the A, B surface around the Y axis is gamma, the rotated straight lines Y1 and Y2 are straight lines Y1 'and Y2', and the included angles between the straight lines Y1 'and Y2' and a horizontal plane (XY plane) are respectively alpha 'and beta';
the straight lines Y1 and Y1' are located on a cone with O as a circle point and the circle a as a bottom, and the geometrical relationship shows that:
the two formulas are combined to obtain:
the radius of the circle B of the bottom surface of the cone rotated by the straight line Y2 around the Y axis is R ', the length from any point on the back line of the Y2 rotation gamma to the vertical line of the horizontal plane is L', and the geometrical relationship shows that:
the two formulas are combined to obtain:
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CN101376433A (en) * | 2008-10-10 | 2009-03-04 | 南京航空航天大学 | Helicopter rotor operation method and system |
CN102678451A (en) * | 2011-06-15 | 2012-09-19 | 华锐风电科技(集团)股份有限公司 | Variable pitch propeller control method for wind generating set |
CN104908976A (en) * | 2015-05-19 | 2015-09-16 | 北京航空航天大学 | Simple rotor mechanism of coaxial dual-rotor helicopter test stand |
CN106786784A (en) * | 2017-03-22 | 2017-05-31 | 广东工业大学 | A kind of wind-powered electricity generation group of planes Poewr control method and system |
CN106989812A (en) * | 2017-05-03 | 2017-07-28 | 湖南科技大学 | Large fan blade modal method of testing based on photogrammetric technology |
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Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
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CN101376433A (en) * | 2008-10-10 | 2009-03-04 | 南京航空航天大学 | Helicopter rotor operation method and system |
CN102678451A (en) * | 2011-06-15 | 2012-09-19 | 华锐风电科技(集团)股份有限公司 | Variable pitch propeller control method for wind generating set |
CN104908976A (en) * | 2015-05-19 | 2015-09-16 | 北京航空航天大学 | Simple rotor mechanism of coaxial dual-rotor helicopter test stand |
CN106786784A (en) * | 2017-03-22 | 2017-05-31 | 广东工业大学 | A kind of wind-powered electricity generation group of planes Poewr control method and system |
CN106989812A (en) * | 2017-05-03 | 2017-07-28 | 湖南科技大学 | Large fan blade modal method of testing based on photogrammetric technology |
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