Rotor total pitch angle measuring device and measuring method

Abstract

The present application belongs to the technical field of rotorcraft testing and measurement, and relates to a rotor total pitch angle measuring device and method. The rotor total pitch angle measuring device comprises a rotor system component and a reference disc component; the rotor system component realizes synchronous pitch change of the blades at the same angle, and realizes adjustment of the rotor total pitch angle; the reference disc component constitutes a reference surface, provides a unified reference for measuring the rotor total pitch angle, and is fixedly connected with the rotating shaft of the rotor system component. The present application constructs a physical reference surface by means of the reference disc component, and has simple overall structure, low processing and using cost, and convenient assembly and construction. The present application directly measures the real rotor total pitch angle by means of the reference disc distance measurement combined with the inverse sine trigonometric function geometric conversion, avoids the calibration error caused by the non-linear factors such as assembly deviation and structural friction which are not considered in pure simulation fitting, and has higher calibration precision.

Description

Technical Field

[0001] This invention belongs to the field of rotorcraft testing and measurement technology, and relates to a rotor collective pitch angle measuring device and measurement method. Background Technology

[0002] Rotorcraft wind tunnel testing is a core method for studying the aerodynamic characteristics, verifying dynamic stability, and tuning control parameters of rotorcraft. In rotorcraft wind tunnel testing, the collective pitch angle is a key parameter that directly determines the aerodynamic load state of the rotor. The setting of the collective pitch angle directly affects the rotor's lift and thrust output, the flapping motion characteristics of the blades, and the aeroelastic coupling characteristics between the rotor and the support structure, thus significantly influencing the dynamic response and stability boundary of the test model. Therefore, accurate measurement of the collective pitch angle is the core foundation for ensuring the reliability of wind tunnel test data, conducting rotor dynamics research, and tuning control parameters; the accuracy of the collective pitch angle measurement directly relates to the validity of the test conclusions.

[0003] Currently, rotor pitch angle measurement mostly uses precision devices such as laser goniometers, visual scanning equipment, and embedded angle sensors. These methods have high accuracy and are suitable for whole-machine finalization and mass production calibration scenarios.

[0004] However, patent CN121493282A discloses a rotor collective pitch calibration device and method, which is suitable for the whole-aircraft installation calibration scenario of helicopters. It has high calibration accuracy and can realize parameter calibration before and after installation. However, the overall structure is relatively complex, with many supporting measurement parts, and high processing and manufacturing costs. The complex integrated measurement structure increases the difficulty of assembly and debugging of the test model. In addition, the multi-part cooperation structure is prone to introducing nonlinear uncertainties such as gaps, assembly deviations, and frictional losses. The operation process is cumbersome and the testing efficiency is low, making it difficult to promote its application in the rapid calibration scenario of small rotor spiral flutter wind tunnel test models.

[0005] Existing technologies lack simple physical measurement schemes based on reference surfaces, making it impossible to quickly measure the true pitch angle of the rotor under different installation conditions. This makes it difficult to efficiently complete the collective pitch parameter calibration of the rotor, which can easily cause deviations in collective pitch control parameters, affecting the accuracy of rotor wind tunnel testing and control debugging, and restricting the efficiency of research and calibration of small rotor wind tunnel test models. Summary of the Invention

[0006] To address the aforementioned problems, this invention proposes a rotor collective pitch angle measuring device and method suitable for rotor-type test models.

[0007] The technical solution of this invention: A rotor collective pitch angle measuring device includes a rotor system assembly 1 and a reference disk assembly 2; the rotor system assembly 1 realizes synchronous pitch and angle variation of the blades to achieve rotor collective pitch angle adjustment; the reference disk assembly 2 forms a reference surface to provide a unified reference for rotor collective pitch angle measurement, and the reference disk assembly 2 is fixedly connected to the rotating shaft 11 of the rotor system assembly 1.

[0008] The rotor system assembly 1 includes a rotating shaft 11, a bushing 12, a pitch control base 13, a pitch control rocker arm 14, a blade clamp 15, blades, and a universal joint hub 19. The rotating shaft 11 is vertically positioned through the center of the universal joint hub 19. The bushing 12 is fitted onto the outer side of the rotating shaft 11, allowing relative sliding and rotation between the rotating shaft 11 and the bushing 12, reducing frictional loss during the rotating shaft 11's movement and ensuring smooth rotation. The bushing 12 is fixed to the pitch control base 13 with an interference fit, achieving a rigid connection with no relative displacement. One end of the pitch control rocker arm 14 is hinged to the pitch control base 13. The variable pitch rocker arm 14 swings synchronously with the pitch control base 13; the other end of the variable pitch rocker arm 14 is connected to the blade clamp 15, and the blade clamp 15 swings and adjusts with the feed displacement of the variable pitch rocker arm 14; the blade clamp 15 is fixedly mounted on the outer circumferential position of the universal joint hub 19 to hold and fix the blades; the three blades are evenly arranged circumferentially and are fixed inside each blade clamp 15 respectively, and the blade clamp 15 achieves a stable assembly with the universal joint hub 19; the rotor system component 1 deflects its attitude with the swinging action of the variable pitch rocker arm 14 to achieve the adjustment of the rotor collective pitch angle and meet the measurement and calibration requirements of different pitch attitudes. The reference disk assembly 2 includes reference disk lobes, a reference disk horizontal locking component, a variable pitch rocker arm guide groove, and a disk-rotating shaft verticality positioning locking component 30. Two reference disk lobes are horizontally fixed and locked together by the reference disk horizontal locking component, and three reference disk lobes form a reference disk, serving as a reference surface. Variable pitch rocker arm guide grooves are formed on adjacent reference disk lobes, and a through hole is formed at the center of the reference disk to cooperate with and fix the rotating shaft 11. The through hole is fixed and locked to the disk-rotating shaft verticality positioning locking component 30, achieving vertical positioning between the reference disk and the rotating shaft 11.

[0009] A method for using a rotor collective pitch angle measuring device includes the following steps: fixing the rotating shaft 11 onto the reference disk assembly 2; pushing the bushing 12, since the bushing 12 is interference-fitted with the pitch control base 13, the pitch control base 13 moves axially together with the bushing 12; the three pitch control arms 14 move axially together with the pitch control base 13, pushing the three blade clamps 15 to rotate, and the three blades rotate together with the three blade clamps 15, thereby changing the rotor collective pitch angle.

[0010] A method for measuring rotor collective pitch angle involves setting a rotor collective pitch in a rotor collective pitch angle measuring device, using a reference disk as a reference surface, and repeatedly measuring the vertical distances from the leading and trailing edges of the three blades to the reference disk. , ,Pick and Substitute the average value into the formula Obtain the rotor collective pitch angle ;in, This is the vertical distance from the leading edge of the blade to the reference disk; This is the vertical distance from the trailing edge of the blade to the reference disk; The blade chord length.

[0011] The beneficial effects of this invention are as follows: This invention relies on a reference disk assembly to construct a physical reference surface, resulting in a simple overall structure, low processing and usage costs, and convenient assembly. This invention employs a reference disk ranging method combined with arcsine trigonometric function geometric conversion to directly measure the true collective pitch angle of the rotor, avoiding calibration errors caused by pure simulation fitting that does not consider nonlinear factors such as assembly deviations and structural friction. The measurement results closely match actual physical conditions, resulting in higher calibration accuracy. Furthermore, this invention features a simple measurement process and low operational threshold, requiring no specialized precision equipment for debugging and calibration. It can quickly complete the data acquisition and angle calculation of multiple blade attitudes, efficiently calibrating the rotor collective pitch angle parameters. It effectively solves the technical problems of traditional calibration devices, such as complex structure, high cost, cumbersome operation, and poor on-site adaptability. The overall structure has strong adaptability and can be widely applied to the collective pitch angle calibration of various small rotor test models, possessing good engineering application and promotion value. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of a rotor collective pitch angle measuring device; Figure 2 This is a detailed structural diagram of the rotor system components; Figure 3 This is a detailed structural diagram of the reference disk assembly; Figure 4 This is a schematic diagram of the blade pitch measurement method; In the figure: 1. Rotor system assembly, 2. Reference disk assembly, 11. Rotor shaft, 12. Bushing, 13. Pitch control base, 14. Pitch control arm, 15. Blade clamp, 16. First blade, 17. Second blade, 18. Third blade, 19. Universal hinge hub, 21. First reference disk flap, 22. Second reference disk flap, 23. Third reference disk flap, 24. First reference disk horizontal locking component, 25. Second reference disk horizontal locking component, 26. Third reference disk horizontal locking component, 27. First pitch control arm guide slot, 28. Second pitch control arm guide slot, 29. Third pitch control arm guide slot, 30. Disk-rotor shaft verticality positioning locking component. Detailed Implementation

[0013] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and technical solutions.

[0014] Example 1 A rotor collective pitch angle measuring device and measuring method are disclosed. The rotor collective pitch angle measuring device includes a rotor system assembly 1 and a reference disk assembly 2.

[0015] like Figure 1 As shown, the reference disk assembly 2 is horizontally fixed above the pitch control base 13. The entire assembly uses a flat reference disk, which remains horizontal and locked in place throughout the entire process, without displacement or angular deflection. It is used to construct a reference surface and provide a unified reference for subsequent rotor collective pitch angle measurements.

[0016] like Figure 2 As shown, the rotating shaft 11 is vertically inserted through the central hole of the universal joint hub 19. A bushing 12 is fitted around the outside of the rotating shaft 11. The bushing 12 can slide and rotate circumferentially relative to the rotating shaft 11, thereby releasing the rotational freedom of the rotating shaft 11 and reducing the frictional resistance of the rotating shaft 11. The outer side of the bushing 12 is pressed and fixed to the pitch control base 13 by an interference fit, so that the bushing 12 and the pitch control base 13 form a rigid structure with no relative sliding or assembly gap between them. One end of the pitch control arm 14 is hinged to the outer side of the pitch control base 13. The three pitch control arms 14 are spaced 120° apart. The other end of the pitch control arm 14 is hinged to the blade clamp 15. Three blade clamps 15 are mounted on the outer side of the universal joint hub 19, and the three blade clamps 15 are spaced 120° apart. The three blade clamps 15 respectively clamp and fix the first blade 16, the second blade 17, and the third blade 18, so that the three blades are firmly connected to the universal joint hub 19.

[0017] like Figure 3As shown, the first reference disk petal 21, the second reference disk petal 22, and the third reference disk petal 23 are spaced 120° apart. The first reference disk petal 21 corresponds to the position of the second blade 17, the second reference disk petal 22 corresponds to the position of the first blade 16, and the third reference disk petal 23 corresponds to the position of the third blade 18. The first reference disc petal 21 and the second reference disc petal 22 are horizontally locked together by the third reference disc horizontal locking member 26 through 6 sets of M4×8 bolts. The first reference disc petal 21 and the third reference disc petal 23 are horizontally locked together by the second reference disc horizontal locking member 25 through 6 sets of M4×8 bolts. The second reference disc petal 22 and the third reference disc petal 23 are horizontally locked together by the first reference disc horizontal locking member 24 through 6 sets of M4×8 bolts. After horizontal locking, the reference disc formed by the first reference disc petal 21, the second reference disc petal 22, and the third reference disc petal 23 is fixed and locked together with the disc-rotating shaft perpendicularity positioning locking member 30 through 12 sets of M4×8 bolts, thereby realizing the perpendicularity positioning between the reference disc and the rotating shaft.

[0018] like Figure 4 The diagram shows a side view of the first blade 16 and the second reference disk petal 22 along the axial direction of the first blade 16. The perpendicular distance between the surface of the second reference disk petal 22 and the leading edge of the first blade 16 is obtained using measuring tools such as a set square. That is, the distance between point A and point B; and the perpendicular distance between the surface of the second reference disk petal 22 and the trailing edge of the first blade 16. That is, the distance between points C and D. The blade chord length is known. Through formula The rotor collective pitch angle can be obtained. .

[0019] Example 2 Step 1: Fix the rotating shaft 11 and push the bushing 12. Because the bushing 12 is interference-fitted with the pitch control base 13, the pitch control base 13 will move axially with the bushing 12. The three pitch control arms 14 will move axially with the pitch control base 13, thereby driving the three blade clamps 15 to rotate. The first blade 16, the second blade 17, and the third blade 18 will rotate together with the three blade clamps 15, thereby changing the rotor collective pitch angle.

[0020] Step 2: After setting a rotor collective pitch angle, using the reference disk as a reference face, measure the vertical distances from the leading and trailing edges of the first blade 16, the second blade 17, and the third blade 18 to the reference disk. Take three measurements for each of the first blade 16, the second blade 17, and the third blade 18. and Substitute the average value into the formula Obtain the rotor collective pitch angle .

[0021] Example 3 The blade chord length used is 34mm, that is When the rotor collective pitch angle is 0 degrees, the blade chord AC is parallel to the reference plane, and the vertical distance from a point on the blade chord AC to the reference plane is 42.567 mm, i.e. = =42.567mm. Five sets of measurement data are as follows: Table 1 Measurement Data Table

Claims

1. A method for measuring the collective pitch angle of a rotor, characterized in that, The rotor collective pitch angle measuring device includes a rotor system assembly (1) and a reference disk assembly (2); the rotor system assembly (1) realizes the synchronous and same pitch change of the blades, and realizes the rotor collective pitch angle adjustment; the reference disk assembly (2) constitutes a reference surface, providing a unified reference for rotor collective pitch angle measurement, and the reference disk assembly (2) is fixedly connected to the rotating shaft (11) of the rotor system assembly (1); The rotor system assembly (1) includes a rotating shaft (11), a bushing (12), a pitch control base (13), a variable pitch rocker arm (14), a blade clamp (15), blades, and a universal joint hub (19); wherein, the rotating shaft (11) is vertically inserted through the center of the universal joint hub (19), and the bushing (12) is sleeved on the outside of the rotating shaft (11), and the rotating shaft (11) and the bushing (12) can slide and rotate relative to each other; the bushing (12) and the pitch control base (13) are fixed with an interference fit to achieve a rigid connection between the two without relative displacement; one end of the variable pitch rocker arm (14) is hinged to the pitch control base (13), The rotor system assembly (1) swings synchronously with the pitch control base (13); the other end of the pitch control arm (14) is connected to the blade clamp (15), and the blade clamp (15) swings and adjusts with the feed displacement of the pitch control arm (14); the blade clamp (15) is fixedly mounted on the outer circumferential position of the universal joint hub (19) to hold and fix the blades; the three blades are evenly arranged circumferentially and are fixed in the interior of each blade clamp (15) respectively, and the blade clamp (15) achieves a stable assembly with the universal joint hub (19); the rotor system assembly (1) deflects its attitude with the swing action of the pitch control arm (14) to achieve the adjustment of the rotor collective pitch angle; The method of using the rotor collective pitch angle measuring device is as follows: fix the rotating shaft (11) on the reference disk assembly (2); push the bushing (12), and since the bushing (12) is interference-fitted with the pitch control base (13), the pitch control base (13) moves axially together with the bushing (12); the three pitch rocker arms (14) move axially together with the pitch control base (13), pushing the three blade clamps (15) to rotate, and the three blades rotate together with the three blade clamps (15), thereby realizing the change of rotor collective pitch angle; After setting a rotor collective pitch on the rotor collective pitch measuring device, the vertical distances from the leading and trailing edges of the three blades to the reference disk are measured multiple times, using the reference disk as the reference surface. , ,Pick and Substitute the average value into the formula Obtain the rotor collective pitch angle ;in, This is the vertical distance from the leading edge of the blade to the reference disk; This is the vertical distance from the trailing edge of the blade to the reference disk; The blade chord length.

2. The method for measuring the collective pitch angle of a rotor according to claim 1, characterized in that, The reference disk assembly (2) includes a reference disk petal, a reference disk horizontal locking member, a variable pitch rocker arm guide groove, and a disk-rotating shaft vertical positioning locking member (30). Among them, two reference disk petals are horizontally fixed and locked together by the reference disk horizontal locking member, and three reference disk petals form a reference disk as a reference surface. Variable pitch rocker arm guide grooves are opened on two adjacent reference disk petals, and a through hole is opened at the center of the reference disk to cooperate with and fix the rotating shaft (11). The through hole is fixed and locked with the disk-rotating shaft vertical positioning locking member (30) to realize the vertical positioning between the reference disk and the rotating shaft (11).

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