A lens shift system suitable for PIV testing

Abstract

The application discloses a lens shift system suitable for PIV (Particle Image Velocimetry) test. When the camera optical axis of the PIV test system is not perpendicular to the flow field measurement area plane, the lens shift system can adjust the angle between the camera imaging chip plane and the camera lens optical axis, accurately focuses the flow field measurement area plane on the camera imaging chip, and provides conditions for obtaining high-quality PIV test tracer particle images. The application provides a camera accurate focusing adjustment system suitable for the PIV test system.

Description

Technical Field

[0001] This invention relates to the field of aerodynamic testing, and more specifically to a lens shift system suitable for PIV testing. Background Technology

[0002] PIV (Positive Infrared) technology is a promising non-contact optical spatial flow velocity field measurement technique. It features low or no interference with the flow field and high spatial resolution, making it one of the most important methods for measuring spatial flow field characteristic parameters. It is widely used in various fluid mechanics experiments and has played a crucial role in the development of fluid mechanics theory and the research and development of various ground transportation vehicles, ships, and aircraft. With the rapid advancements in next-generation materials technology, laser technology, imaging technology, and image processing technology, as well as the emergence of new theories, PIV technology has also experienced rapid development, moving towards larger field of view, higher precision, higher spatiotemporal resolution, and volumetric spatial measurement and particle tracking.

[0003] In routine PIV testing, especially the 2D3C (2 Dimensional 3 Component) test, such as Figure 1 As shown, the imaging optical axes of the two PIV experimental system cameras are not perpendicular to the plane of the flow field measurement area, but at an angle, such as 45°. Due to the limited depth of field of the cameras, using a conventional lens mounting method—that is, directly mounting a commonly used camera lens onto the PIV experimental system camera (in this case, the normal of the camera imaging chip plane is aligned with the optical axis of the lens)—results in PIV tracer particle images exhibiting strip-shaped localized focus while most other areas remain out of focus, thus failing to obtain high-quality PIV tracer particle images. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a lens shift system suitable for PIV experiments, which can change the angle between the lens optical axis and the camera optical axis to achieve precise focusing of planar tracer particles in the flow field measurement area during PIV experiments.

[0005] In order to achieve the above-mentioned purposes, the application adopts the following technical scheme: a lens shift axis system suitable for PIV test, characterized in that it comprises a driven rotating shaft support, a base, a lens adapter ring, an optical axis rotating angle adjusting and locking rod, a base, a driving shaft, a lever, a camera supporting plate, a base matching rotating assembly, a camera adapter ring, a rotating shaft fixing seat, a shaft sleeve and a driven shaft, the camera of the PIV test system is installed on the base matching rotating assembly through the camera adapter ring, and the camera installation is reinforced through the camera supporting plate, the lens of the camera is installed on the base through the lens adapter ring, and the base is fixed with the external structure through the base, the matching surface of the base and the base matching rotating assembly is arc-shaped, the camera supporting plate is installed on the base matching rotating assembly, when the camera of the PIV test system is installed on the camera adapter ring, the camera is fastened through the camera supporting plate, and a second supporting point is provided for the camera; the driving shaft is fastened and connected with the base matching rotating assembly through the rotating shaft fixing seat and the shaft sleeve, and the optical axis rotating angle adjusting and locking rod is installed on the base, when adjustment is needed, the optical axis rotating angle adjusting and locking rod is manually adjusted, and then the lever is driven to rotate, the lever transmits the movement to the driving shaft, the driving shaft is fastened and connected with the base matching rotating assembly through the rotating shaft fixing seat and the shaft sleeve, the rotation of the driving shaft drives the base matching rotating assembly to rotate, so that the angle between the lens optical axis and the camera optical axis is changed, the camera focusing adjustment of the PIV test system is realized, the adjustment of the lens optical axis relative to the camera optical axis is realized, and the camera lens and the base remain unchanged.

[0006] Further, the axis of the driving shaft and the driven shaft is the center axis of the cylindrical surface matching surface of the base and the base matching rotating assembly.

[0007] The application has the following advantages and beneficial effects:

[0008] (1) The cylindrical surface is used as the mechanism angle adjustment matching surface, the adjustment direction has good consistency and high precision;

[0009] (2) When the angle between the lens optical axis and the camera optical axis is adjusted, the position of the lens remains unchanged, the camera is rotated with the mechanism, the flow field measurement plane region aligned by the lens remains basically unchanged, and the problem that the flow field measurement plane region aligned by the lens is greatly changed due to the rotation of the lens is avoided;

[0010] (3) The camera supporting plate provides a second camera installation fixing point on the basis of installing the camera through the camera adapter ring, the camera installation firmness is greatly improved, and the camera supporting plate can also be moved and adjusted according to the specific camera specifications, thereby providing convenience for camera installation. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 It is a 2D3C PIV test layout schematic diagram;

[0012] Figure 2This is a schematic diagram of a lens shifting system suitable for PIV testing according to the present invention.

[0013] Figure 3 for Figure 2 A schematic diagram of its breakdown.

[0014] Among them, 1-driven rotating shaft support, 2-base, 3-lens adapter ring, 4-optical axis angle adjustment and locking rod, 5-base, 6-drive shaft, 7-lever, 8-camera support plate, 9-base mating rotating assembly, 10-camera adapter ring, 11-rotating shaft fixing seat and bushing, 12-driven shaft. Detailed Implementation

[0015] The specific embodiments of the present invention will be described in detail below with reference to the overview and accompanying drawings.

[0016] Example 1

[0017] like Figures 2-3 As shown, a lens shifting system suitable for PIV testing includes a driven pivot support 1, a base 2, a lens adapter ring 3, an optical axis angle adjustment and locking rod 4, a base 5, a drive shaft 6, a lever 7, a camera support plate 8, a base-fitting rotating assembly 9, a camera adapter ring 10, a pivot fixing seat and bushing 11, and a driven shaft 12. The camera of the PIV testing system is mounted on the base-fitting rotating assembly 9 via the camera adapter ring 10, and the camera mounting is reinforced by the camera support plate 8. The camera lens is mounted on the base 2 via the lens adapter ring 3 and fixed to the external structure by the base 5. The mating surface between the base 2 and the base-fitting rotating assembly 9 is arc-shaped. The camera support plate 8 is mounted on the base-fitting rotating assembly 9. When the camera of the PIV testing system is mounted on the camera adapter ring... After mounting, the camera is secured by the camera support plate 8, providing a second support point. The drive shaft 6 is securely connected to the base rotating assembly 9 via a rotating shaft fixing seat and bushing 11. The optical axis angle adjustment and locking rod 4 is mounted on the base 5. When adjustment is needed, the optical axis angle adjustment and locking rod 4 is manually adjusted, which in turn pushes the lever 7 to rotate. The lever 7 transmits the motion to the drive shaft 6. The drive shaft 6 and the base rotating assembly 9 are securely connected via the rotating shaft fixing seat and bushing 11. The rotation of the drive shaft 6 will drive the base rotating assembly 9 to rotate, thereby changing the angle between the lens optical axis and the camera optical axis, realizing the focus adjustment of the PIV test system camera, and realizing the adjustment of the lens optical axis relative to the camera optical axis, while the camera lens and the base 2 remain stationary. The axis of the drive shaft 6 and the driven shaft 12 is the central axis of the cylindrical surface of the base 2 and the base rotating assembly 9.

Claims

1. A lens shift system suitable for PIV testing, characterized in that, The PIV test system comprises a driven rotating shaft support (1), a base (2), a lens adapter ring (3), an optical axis angle adjusting and locking rod (4), a base (5), a driving shaft (6), a lever (7), a camera supporting plate (8), a base matching rotating assembly (9), a camera adapter ring (10), a rotating shaft fixing base and shaft sleeve (11) and a driven shaft (12).

2. A lens shift system for PIV testing according to claim 1, wherein: The camera of the PIV test system is installed on the base matching rotating assembly (9) through the camera adapter ring (10), and the camera installation is reinforced through the camera supporting plate (8); the lens of the camera is installed on the base (2) through the lens adapter ring (3) and is fixed with the external structure through the base (5); the matching surface of the base (2) and the base matching rotating assembly (9) is a cylindrical surface; the camera supporting plate (8) is installed on the base matching rotating assembly (9); after the camera of the PIV test system is installed on the camera adapter ring (10), the camera is fastened through the camera supporting plate (8) to provide a second supporting point for the camera; the driving shaft (6) is fastened and connected with the base matching rotating assembly (9) through the rotating shaft fixing base and shaft sleeve (11); the optical axis angle adjusting and locking rod (4) is installed on the base (5); when adjustment is needed, the optical axis angle adjusting and locking rod (4) is manually adjusted, the lever (7) is driven to rotate, the movement is transmitted to the driving shaft (6), the driving shaft (6) is fastened and connected with the base matching rotating assembly (9) through the rotating shaft fixing base and shaft sleeve (11), the rotation of the driving shaft (6) drives the base matching rotating assembly (9) to rotate, thereby changing the angle between the lens optical axis and the camera optical axis, realizing the focusing adjustment of the camera of the PIV test system and the adjustment of the lens optical axis relative to the camera optical axis, while the camera lens and the base (2) remain unchanged. The shaft center of the driving shaft (6) and the driven shaft (12) is the center axis of the cylindrical matching surface of the base (2) and the base matching rotating assembly (9).

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