CN102122108A - Independently moving and independently rotating two-degree-of-freedom parallel mechanism - Google Patents

Abstract

A two-degree-of-freedom parallel mechanism for independent movement and independent rotation, including a sleeve (3) and a hollow shaft (1) slidably and rotatably supported in the sleeve, and a hollow shaft rack part ( 6) and the hollow shaft gear part (10), the first motor is fixed on one side of the sleeve, and the second motor is fixed on the other side, the first motor gear (7) on the first motor and the hollow shaft rack Partially meshed, the second motor gear (12) on the second motor meshes with the hollow shaft gear section (10). The invention can make the camera focus automatically, it can give the control signal through the automatic control technology, directly control the movement of the convex lens driven by the motor, and can know the change of the convex lens relative to the original position, and provide relevant parameters for the measurement of the camera, which is not only flexible and convenient , the response speed meets the focusing requirements, and the circuit design can be greatly simplified.

Description

Two degrees of freedom parallel mechanism with independent movement and independent rotation

technical field

The invention relates to a two-degree-of-freedom parallel mechanism with independent movement and independent rotation.

Background technique

Modern precision measurement technology is a comprehensive interdisciplinary subject integrating precision machinery, optics, electronics, sensors, and computer technology. Visual measurement has developed rapidly in recent years by integrating the above technologies. In visual measurement, whether the target imaging truly reflects the actual measured physical quantity is very important. A clear image is the basis for subsequent image processing and analysis. It is directly related to the measurement accuracy of the entire system, and whether the image is correctly focused is the key factor.

In the prior art, various autofocus methods have their own limitations. For example, in the focusing methods of infrared ranging and ultrasonic ranging, when the measured target has a strong absorption effect on infrared light or ultrasonic waves, the ranging system will fail or the focus will be inaccurate; while the focus detection of the contrast method is restricted by the lighting conditions , when the light is dim or the difference between the subject and the background is very small, focusing will be difficult or even lose its effect. Camera imaging generally adopts a pinhole model, and the focal length of the lens is fixed after calibration, but the movement of the object changes, resulting in a change in distance, which makes the image blurred. At this time, refocusing is required, but the focal length change after refocusing is unknown , because for now, most cameras do not know the focal length after focusing, so measurement becomes impossible.

Contents of the invention

The object of the present invention is to provide a two-degree-of-freedom parallel mechanism with independent movement and independent rotation, so as to overcome the above-mentioned defects, which can realize automatic focusing of the camera without changing the focal length of the lens.

Above-mentioned object is to realize by following technical scheme of the present invention: the parallel mechanism of two degrees of freedom of independent movement and independent rotation, comprises sleeve, front bearing, rear bearing, and is slidably and rotatably supported on the described front bearing and rear bearing by this front bearing and rear bearing The hollow shaft in the sleeve, the hollow shaft rack part and the hollow shaft gear part are formed on the outer ring of the hollow shaft, and the sleeve is provided with a second part corresponding to the hollow shaft rack part and the hollow shaft gear part. One meshing groove and the second meshing groove, the first motor is fixed on one side of the sleeve, the second motor is fixed on the other side, the first motor gear is installed on the output shaft of the first motor, the first The motor gear meshes with the hollow shaft rack part through the first meshing groove, and the second motor gear is installed on the output shaft of the second motor, and the second motor gear meshes with the said second meshing groove through the second meshing groove. The hollow shaft gear is partially meshed.

Optionally, the first motor is fixed on one side of the sleeve through a first motor fixing frame, and the second motor is fixed on the other side of the sleeve through a second motor fixing frame.

Optionally, both the front bearing and the rear bearing are copper sleeves.

Optionally, the sleeve is connected to the camera by a threaded connection.

The advantages and effects of the present invention are: the two-degree-of-freedom parallel mechanism of independent movement and independent rotation of the present invention can make the camera focus automatically, and it can provide control signals through automatic control technology, directly control the motion of the motor-driven convex lens, and can know The change of the convex lens relative to the original position provides relevant parameters for the measurement of the camera, which is not only flexible and convenient, the response speed meets the focusing requirements, but also greatly simplifies the circuit design.

Description of drawings

Fig. 1 is a schematic structural diagram of a two-degree-of-freedom parallel mechanism according to a specific embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view taken along line A-A in Fig. 1 .

Fig. 3 is a schematic diagram of a two-degree-of-freedom parallel mechanism of the present invention installed on a camera and equipped with a convex lens.

Figure 4 shows that the image cannot fall on the CCD face, so the image is not clear.

Figure 5 shows that the image falls on the CCD surface after adjusting the convex lens, so that the image is clear.

Figure 6 shows that when the axis of the convex lens is not parallel to the axis of the hollow shaft, the image is clear through adjustment.

Figure 7 shows that on the basis of the clear image in Figure 6, the second motor rotates the convex lens, so the image is not clear.

In the figure: 1 hollow shaft; 2 front bearing; 3 sleeve; 4 first motor; 5 first motor fixing frame; 6 hollow shaft rack part; 7 first motor gear; 8 rear bearing; Gear part; 11 second motor fixing frame; second motor gear 12.

Detailed ways

The specific implementation of the two-degree-of-freedom parallel mechanism with independent movement and independent rotation of the present invention will be described below with reference to the accompanying drawings.

As shown in Figure 1 and Figure 2: the two-degree-of-freedom parallel mechanism of the present invention includes a hollow shaft 1, a front bearing 2 (such as a copper sleeve), a sleeve 3, a first motor 4, a first motor fixing frame 5, a first Motor gear 7, rear bearing 8 (such as using a copper sleeve), second motor 9, second motor fixing frame 11 and second motor gear 12, the hollow shaft 1 is provided with a hollow shaft rack part 6 and a hollow shaft gear part 10.

The positional relationship and connection relationship of the above components are as follows:

The hollow shaft 1 is installed in the sleeve 3 through the front bearing 2 (preferably the front copper sleeve) and the rear bearing 8 (preferably the rear copper sleeve), and the front bearing 2 and the rear bearing 8 are fixed at both ends of the sleeve 3, and make The axes of the hollow shaft 1, the sleeve 3, the front bearing 2 and the rear bearing 8 coincide, and the hollow shaft 1 can slide and roll in the sleeve 3. In addition, the front bearing 2 and the rear bearing 8 are not limited to the above-mentioned copper sleeves, which can be It is a rolling bearing, a sliding bearing, a linear bearing, etc., as long as its specifications can ensure that the hollow shaft 1 can slide and roll in the sleeve. The first motor fixing frame 5 is fixed on the sleeve 3, the first motor 4 (ie, the motor for moving) is installed on the first motor fixing frame 5, the first motor gear 7 is installed on the output shaft of the first motor 4, and the first motor gear 7 is installed on the output shaft of the first motor 4. A motor gear 7 forms a rack and pinion engagement with the rack part 6 on the hollow shaft 1 through the first meshing groove provided on the sleeve 3, and the second motor holder 11 is fixed on the sleeve 3, and the second motor 9 ( That is, the rotating motor) is installed on the second motor fixing frame 11, the second motor gear 12 is installed on the output shaft of the second motor 9, and the second motor gear 12 is connected with the hollow shaft 1 through the second meshing groove opened by the sleeve 3. The upper gear portion 10 forms a gear mesh.

It can be seen from the above description that the independent movement and independent rotation two-degree-of-freedom parallel mechanism of the present invention is mainly characterized in that one section of the outer ring of the hollow shaft 1 is processed into the hollow shaft rack part 6 and one section is processed into the hollow shaft gear part 10, and the hollow shaft 1 is supported in the sleeve 3 through the front and rear bearings 2 and 8, the hollow shaft 1 and the bearing 3 can slide, and can also rotate around the axis of the bearing 3. The first motor 4 is fixed on one side of the sleeve 3 by the first motor fixing frame 5, the first motor gear 7 is installed on the output shaft of the first motor 4, the first motor gear 7 is meshed with the hollow shaft rack part 6, In this way, the first motor 4 drives the hollow shaft 1 to move forward and backward through the meshing of the first motor gear 7 and the hollow shaft rack 6 . The second motor 9 is fixed on the other side of the sleeve 3 by the second motor holder 11, the second motor gear 12 is installed on the output shaft of the second motor 9, and the second motor gear 12 is partially meshed with the hollow shaft gear, so that the second motor gear 12 is partially meshed with the hollow shaft gear. The second motor 9 drives the hollow shaft 1 to rotate through the second motor gear 12 and meshes with the hollow shaft gear part. Since the two independent movements are driven by the hollow shaft, a two-degree-of-freedom parallel mechanism is realized.

The application of the present invention shows that during the autofocus process, as shown in Figure 3, the sleeve 3 is screwed to the camera, and a convex lens is installed in the middle of the hollow shaft 1, and the image collected by the CCD (that is, the charge-coupled device image sensor) is transmitted to the computer In this process, the computer processes the image to determine whether the image is clear, if not, a driving signal is given to the first motor 4 to make the first motor 4 run, and the first motor gear 7 is driven to rotate, and the first motor gear 7 and the hollow shaft The rack part 6 meshes, drives the hollow shaft 1 (convex lens) to move along the axis direction, adjusts the object distance and image distance, and when the image is clearest, the first motor 4 stops rotating. Figure 4 shows that the image cannot fall on the CCD surface , the image is not clear. Figure 5 shows that the adjusted image falls on the CCD surface (that is, the charge-coupled device array), the image is clear, and the distance that the convex lens moves can be known.

Another advantage of the present invention is that it can be estimated whether the position of the convex lens installed in the hollow shaft is correct, that is, whether the mirror surface of the convex lens is perpendicular to the axis of the hollow shaft. As shown in Figure 6, assuming that the mirror surface of the convex lens is not perpendicular to the hollow shaft, the image is clearly formed on the CCD surface through adjustment. If the second motor 9 is rotated at this time, the second motor gear 12 drives the hollow shaft 1 to rotate, as shown in FIG. As shown in Figure 7, if the image becomes blurred at this time, it proves that the mirror axis of the convex lens is not parallel to the axis of the hollow shaft. At this time, the installation of the convex lens must be readjusted to ensure the accuracy of the measurement.

The various specific technical features described in the above specific implementation manners can be combined in any suitable manner, and they also fall within the scope of the present invention. At the same time, any combination of various implementations of the present invention can also be made, as long as they do not violate the idea of the present invention, they should also be regarded as the disclosed content of the present invention. In addition, the present invention is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention. The protection scope of the present invention is defined by the claims.

Claims (4)

1. A two-degree-of-freedom parallel mechanism that independently moves and rotates independently, and is characterized in that it includes a sleeve (3), a front bearing (2), a rear bearing (8), and through the front bearing (2) and the rear bearing (8) ) The hollow shaft (1) slidably and rotatably supported in the sleeve (3), the hollow shaft rack part (6) and the hollow shaft gear part (10) are formed on the outer ring of the hollow shaft, the The sleeve (3) is provided with a first meshing groove and a second meshing groove corresponding to the hollow shaft rack part (6) and the hollow shaft gear part (10), and one side of the sleeve (3) is fixed There is a first motor (4), and a second motor (9) is fixed on the other side, and a first motor gear (7) is installed on the output shaft of the first motor, and the first motor gear is engaged via the first The slot meshes with the hollow shaft rack part (6), and the second motor gear (12) is installed on the output shaft of the second motor, and the second motor gear is connected with the hollow shaft through the second meshing groove. The gear section (10) meshes. 2. The two-degree-of-freedom parallel mechanism with independent movement and independent rotation according to claim 1, characterized in that, the first motor (4) is fixed on the sleeve (3) through the first motor fixing bracket (5) ), the second motor (9) is fixed on the other side of the sleeve (3) through a second motor fixing bracket (11). 3. The two-degree-of-freedom parallel mechanism with independent movement and independent rotation according to claim 1, characterized in that, both the front bearing (2) and the rear bearing (8) are copper sleeves. 4. The two-degree-of-freedom parallel mechanism with independent movement and independent rotation according to claim 1, characterized in that the sleeve (3) is connected to the camera through a threaded connection.

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