A method for positioning and trajectory measurement of a swing block

Abstract

This invention discloses a method for positioning and trajectory measurement of a rotating pendulum block. A rotating main body rotates in a plane around its rotation center, while multiple pendulum blocks reciprocate in a plane within the range of limiting holes on both sides of the rotating main body. Positioning holes are provided on both the rotating main body and the pendulum blocks. A high-speed camera records the initial positions of the positioning holes on the rotating main body and the pendulum blocks. The center positions of the high-speed camera and the rotating main body are fixed, and video is recorded until both the rotating main body and the pendulum blocks stop moving. A video processing module extracts images at set intervals, calculates the speed and angle of the rotating main body's rotation, the speed, direction and angle of the rotation of the pendulum block's central secondary positioning hole, and the distance between the pendulum block's central secondary positioning hole and the rotation center. All time points are sequentially connected according to the video recording times to obtain the motion trajectory curve of the pendulum blocks as they move with the rotating main body. The advantage of this invention is that it obtains the motion trajectory of the pendulum blocks.

Description

Technical Field

[0001] This invention relates to a method for measuring the trajectory of rotary motion, and in particular to a method for positioning and measuring the trajectory of a rotary pendulum. Background Technology

[0002] The structure combining a pendulum block and a rotating body is widely used in the automotive industry. Studying the motion law of the pendulum block is an important direction for optimizing vibration reduction. By analyzing the structure of the rotating body and the pendulum block, this paper analyzes their velocity relationship, relative position changes, and studies the dynamic characteristics of the pendulum block. Traditional methods involve installing sensors on the pendulum block, which suffers from high cost, poor versatility, and, for smaller pendulum blocks, the mass of the sensors can cause deviations in the measured motion trajectory. Utilizing a high-speed camera for non-contact measurement can better capture the motion position and trajectory changes of the pendulum block without affecting the object's inherent motion characteristics. Current research on pendulum blocks mostly measures changes in their motion angles, but the actual motion trajectory of the pendulum block is usually not aligned with the center of the rotating body. This application aims to address the problem that existing technologies only identify the motion angle of the pendulum block but cannot determine its motion law; this is the key area for improvement. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for positioning and trajectory measurement of a rotating pendulum block, which uses a high-speed camera to perform non-contact measurement of the movement position and trajectory of the pendulum block during rotation.

[0004] To address the above technical problems, this invention provides a method for positioning and trajectory measurement of a rotary pendulum block, comprising the following steps:

[0005] Step S1: The rotating body rotates in a plane around the rotation center, and multiple swing blocks reciprocate in a plane within the range of the limiting holes on both sides of the rotating body. Positioning holes are provided on both the rotating body and the swing blocks.

[0006] Limiting holes are distributed on both sides of the swing block to limit the range of motion of the swing block on the rotating body;

[0007] The shape of the limiting hole is not limited; it can be determined as an arc, a straight line, a serpentine shape, or any other arbitrary shape according to the actual movement requirements of the swing block.

[0008] Step S11: Several pendulum blocks are evenly distributed on the rotating body in a circular pattern. There is no overlap in the movement of each pendulum block, and their motion characteristics are consistent. There are protruding handle blocks on both radial sides of the rotating body. There is a main positioning hole in the center of each handle block, and a secondary positioning hole in the center of each pendulum block.

[0009] The more blocks there are, the smaller the volume will be. The number is 2-8, and it is generally best to arrange four.

[0010] The trajectory and speed of the pendulum block on the rotating body are affected by the shape of the rotating body and the limiting hole. That is, the speed and direction of the pendulum block are different from those of the rotating body. Different pendulum blocks may move in the same direction as or opposite to the rotating body, but the direction and speed of each pendulum block are the same.

[0011] The movement of the pendulum block depends on the shape of the rotating body and the limiting hole. When the speed and direction of the rotating body are constant, the path length and direction of the pendulum block in the S-shaped limiting hole are different from those in the straight limiting hole in the same time, so the speeds are also different.

[0012] Step S12: The rotating body moves in a circle around the rotation center, and the center of the main positioning hole is on the same circle. Each pendulum block moves back and forth on the rotating body, and the center of the secondary positioning hole on the pendulum block moves in a curve. That is, the trajectory of the center of the circle at different times is not on the same circle.

[0013] Step S2: Use a high-speed camera to record the initial position of the positioning holes of the rotating body and the pendulum block. Fix the center position of the high-speed camera and the rotating body. The initial position of the rotating body and the pendulum block can be any position. Record the video until the rotating body and the pendulum block stop moving.

[0014] Step S21: The high-speed camera is fixed in the center and faces the rotation center to capture the complete rotating body and the movement area of ​​the pendulum block, especially the positional changes of the main positioning hole and the secondary positioning hole.

[0015] Step S3: The video processing module extracts images from the recorded video at set intervals, calculates the speed and angle of the rotating main body, the speed, direction and angle of the rotation of the secondary positioning hole at the center of the pendulum block, and the distance between the secondary positioning hole at the center of the pendulum block and the rotation center.

[0016] Establish an XOY coordinate system with the rotation center as the origin. Identify the initial position of the center of the secondary positioning hole of the pendulum block and the angle between it and the X-axis as θ0. The initial position of the center of the main positioning hole of the rotating main body coincides with the X-axis. The angle of rotation of the center of the main positioning hole of the rotating main body between the i-th image and the (i-1)-th image is θ. a The rotation angle of the center of the auxiliary positioning hole of the swing block is θ. i The radius between the center of the main positioning hole of the rotating body and the center of rotation is R. a The radius of the center of the secondary positioning hole of the pendulum block relative to the center of rotation is R. i Record the positions of the center positioning hole of the rotating main body and the center positioning hole of the swing block at time i;

[0017] Calculate the velocity of the rotating body at time i. Where: θ a In radians, unit: rad; or

[0018] Calculate the velocity of the rotating body at time i. Where: θ a Angles, unit: degrees;

[0019] The velocity of the pendulum block at time i Clockwise motion is considered the positive direction, and counterclockwise motion is considered the negative direction.

[0020] At time i, the position P of the center of the main positioning hole of the rotating main body is... a =(-R a cosθ a R a sinθ a );

[0021] At time i, the position P of the center of the secondary positioning hole at the center of the pendulum block is... i =(R i cos(θ0-θ i ),Ri sin(θ0-θ i (a = 1, 2, 3, 4…, i = 1, 2, 3, 4…), determine the relative positional changes of the rotating main body and the pendulum block; Step S4: sequentially connect all P at times 1 to i according to the video recording time. a P i By taking a point, the motion trajectory curve of the pendulum block as it moves with the rotating main body is obtained, and the motion characteristics of the pendulum block are further analyzed.

[0022] The superior effects of this invention are as follows:

[0023] 1) The pendulum block reciprocates in the limiting hole. The same position may correspond to different motion trajectories. This application determines the position change of the pendulum block by time sequence, and then obtains the motion trajectory of the pendulum block, further clarifying the motion characteristics of the pendulum block.

[0024] 2) Using non-contact measurement methods, the motion trajectory changes of the pendulum block can be determined more accurately, avoiding the influence of adding sensors on the measurement results. Attached Figure Description

[0025] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0026] Figure 1 This is a schematic diagram illustrating the relative motion between the rotating body and the pendulum block in a specific embodiment of the present invention;

[0027] Figure 2 This is a schematic diagram illustrating the positional changes of the pendulum block in a specific embodiment of the present invention;

[0028] Explanation of the labels in the diagram

[0029] 1—Rotating body; 2—Main positioning hole;

[0030] 3—Main positioning hole after rotational motion; 4—Secondary positioning hole after rotational motion;

[0031] 5—Secondary positioning hole; 6—Swing block;

[0032] 7—Limiting hole;

[0033] V1 is the speed of the rotating main body;

[0034] V2 is the speed of the pendulum's movement;

[0035] R1 is the radius of motion of the center of the main positioning hole relative to the center of rotation;

[0036] R2 is the radius of motion of the center of the secondary positioning hole relative to the rotation center;

[0037] R3 is the initial radius of the center of the secondary positioning hole relative to the rotation center;

[0038] R4 is the radius of the inner hole of the rotating body;

[0039] θ1 is the angle of motion of the center of the main positioning hole;

[0040] θ2 is the angle of motion of the center of the secondary positioning hole;

[0041] θ3 is the initial relative position angle between the center of the main positioning hole and the center of the secondary positioning hole. Detailed Implementation

[0042] The following describes in detail an example of the present invention with reference to the accompanying drawings, taking four swing blocks, each with a positioning hole, as an example.

[0043] like Figure 1 and Figure 2 As shown, the present invention provides a method for positioning and trajectory measurement of a rotary pendulum block, comprising the following steps:

[0044] Step S1: The rotating body 1 rotates in a plane around the rotation center O, and the swing block 6 reciprocates in a plane on the rotating body 1 within the range of the limiting hole 7. The rotating body 1 is provided with a main positioning hole 2, and the swing block 6 is provided with a secondary positioning hole 5.

[0045] Step S11: There are four swing blocks 6 evenly distributed on the rotating body 1. There is no overlap between the movements of each swing block 6, and the movement characteristics are consistent. There are protruding handle blocks on both radial sides of the rotating body 1, with a main positioning hole 2 at the center and a secondary positioning hole 5 at the center of the swing block 6.

[0046] The trajectory and speed of the swing block 6 on the rotating body 1 are affected by the shape of the rotating body 1 and the limiting hole 7. That is, the speed and direction of the swing block 6 are different from those of the rotating body 1. Different swing blocks 6 may move in the same direction as or opposite to the rotating body 1, but different swing blocks 6 may move in the same direction and speed.

[0047] Step S12: The rotating body 1 moves in a circle around the rotation center O, and the center of the main positioning hole 2 is on the same circle. The swing block 6 moves back and forth on the rotating body 1, and the center of the secondary positioning hole 5 on the swing block 6 moves in a curve. That is, the trajectory of the center of the circle at different times is not on the same circle.

[0048] Step S2: Use a high-speed camera to record the initial positions of the main positioning hole 2 and the secondary positioning hole 5 of the rotating body 1 and the pendulum block 6. Fix the center position of the high-speed camera and the rotating body 1. The initial positions of the rotating body 1 and the pendulum block 6 are arbitrary. Record the video until the rotating body 1 and the pendulum block 6 stop moving.

[0049] The high-speed camera is fixed at its center and faces the rotation center O, and can capture the complete movement area of ​​the rotating body 1 and the swing block 6, especially the positional changes of the main positioning hole 2 and the secondary positioning hole 5.

[0050] Step S3: The video processing module extracts the recorded video into images at intervals Δt, such as every 0.5 seconds, and calculates the rotation speed and angle of the rotating main body 1, the rotation speed, direction and angle of the pendulum block 6, and the distance between the central secondary positioning hole 5 of the pendulum block 6 and the rotation center O.

[0051] An XOY coordinate system is established with the rotation center O as the origin. The initial position of the center of the secondary positioning hole 5 of the pendulum block 6 and the angle between it and the X-axis is identified as θ3. The initial position of the center of the main positioning hole 2 of the rotating body 1 coincides with the X-axis. Taking the rotating body 1 moving clockwise and the pendulum block 6 moving counterclockwise for a period of time as an example, the rotation angle of the center of the main positioning hole 2 of the rotating body 1 is θ1, the rotation angle of the center of the secondary positioning hole 5 of the pendulum block 6 is θ2, the radius between the center of the main positioning hole 2 of the rotating body 1 and the rotation center O is R1, the initial radius between the center of the secondary positioning hole 5 of the pendulum block 6 and the rotation center O is R3, and the stopping radius between the center of the secondary positioning hole 4 and the rotation center O after the rotation of the pendulum block 6 is R2. Thus, the position and direction of the pendulum block 6 at any time are determined.

[0052] Calculate the velocity of rotating body 1

[0053] Speed ​​of block 6

[0054] With clockwise motion as the positive direction and counterclockwise motion as the negative direction, the initial position of the main positioning hole 2 is (-R1, 0), and the position of the main positioning hole 2 after rotation is (-R1cosθ1, R1sinθ1); the initial position of the secondary positioning hole 5 is (-R3cosθ3, R3sinθ3), and the position of the secondary positioning hole 4 after rotation is (-R2cos(θ3-θ2), R2sin(θ3-θ2)). Thus, the relative positional changes of the rotating body 1 and the pendulum block 6 are determined.

[0055] Step S4: Connect the positions of the auxiliary fixed holes 4 after the rotational motion according to the time recorded by the video, so as to obtain the motion trajectory curve of the pendulum block 6 as it moves with the rotating body 1. Further analyze the motion characteristics of the pendulum block 6 to obtain the motion law of the pendulum block 6.

[0056] The method of this invention can not only measure the motion angle of the pendulum, but also locate the motion position of the pendulum, and further obtain the change in the motion trajectory of the pendulum.

[0057] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for positioning and trajectory measurement of a rotary pendulum block, characterized in that: Includes the following steps: Step S1: The rotating body rotates in a plane around the rotation center, and multiple swing blocks reciprocate in a plane within the range of the limiting holes on both sides of the rotating body. Positioning holes are provided on both the rotating body and the swing blocks. Step S2: Use a high-speed camera to record the initial positions of the positioning holes of the rotating body and the pendulum block, fix the center position of the high-speed camera and the rotating body, and record the video until the rotating body and the pendulum block stop moving; Step S3: The video processing module extracts images from the recorded video at set intervals, calculates the speed and angle of the rotating main body, the speed, direction and angle of the rotation of the secondary positioning hole at the center of the pendulum block, and the distance between the secondary positioning hole at the center of the pendulum block and the rotation center; Establish an XOY coordinate system with the rotation center as the origin. Identify the initial position of the center of the secondary positioning hole of the pendulum block and the angle between it and the X-axis as θ0. The initial position of the center of the main positioning hole of the rotating main body coincides with the X-axis. The angle of rotation of the center of the main positioning hole of the rotating main body between the i-th image and the (i-1)-th image is θ. a The rotation angle of the center of the auxiliary positioning hole of the swing block is θ. i The radius between the center of the main positioning hole of the rotating body and the center of rotation is R. a The radius of the center of the secondary positioning hole of the pendulum block relative to the center of rotation is R. i Record the positions of the center positioning hole of the rotating main body and the center positioning hole of the swing block at time i; Calculate the velocity of the rotating body at time i. Where: θ a In radians, unit: rad; or Calculate the velocity of the rotating body at time i. Where: θ a Angles, unit: degrees; The velocity of the pendulum block at time i Clockwise motion is considered the positive direction, and counterclockwise motion is considered the negative direction. At time i, the position P of the center of the main positioning hole of the rotating main body is... a =(-R a cosθ a R a sinθ a ); At time i, the position P of the center of the secondary positioning hole at the center of the pendulum block is... i =(R i cos(θ0-θ i ),R i sin(θ0-θ i (a = 1, 2, 3, 4…, i = 1, 2, 3, 4…), determine the relative positional changes of the rotating main body and the pendulum block; Step S4: sequentially connect all P at times 1 to i according to the video recording time. a P i The point is used to obtain the trajectory curve of the pendulum block as it moves with the rotating main body.

2. The method for positioning and trajectory measurement of a rotary pendulum block according to claim 1, characterized in that... Step S1 includes the following specific steps: Step S11: Several pendulum blocks are evenly distributed on the rotating body in a circular pattern. There are protruding handle blocks on both radial sides of the rotating body. There is a main positioning hole in the center of the handle block and a secondary positioning hole in the center of each pendulum block. Step S12: The rotating body moves in a circle around the rotation center, and the center of the main positioning hole is on the same circle. Each pendulum block moves back and forth on the rotating body, and the center of the secondary positioning hole on the pendulum block moves in a curve. That is, the trajectory of the center of the circle at different times is not on the same circle.

3. The method for positioning and trajectory measurement of a rotary pendulum block according to claim 2, characterized in that... The trajectory and speed of the pendulum block on the rotating body are influenced by the shape of the rotating body and the limiting hole. Different pendulum blocks move in the same direction as or opposite to the rotating body, and the direction and speed of each pendulum block are the same.

4. The method for positioning and trajectory measurement of a rotary pendulum block according to claim 1, characterized in that... The limiting holes are distributed on both sides of the swing block and are used to limit the range of motion of the swing block on the rotating body.

5. The method for positioning and trajectory measurement of a rotary pendulum block according to claim 4, characterized in that... The shape of the limiting hole is not limited, and can be determined as arc-shaped, straight, serpentine, or any other arbitrary shape according to the actual movement requirements of the swing block.

6. The method for positioning and trajectory measurement of a rotary pendulum block according to claim 1, characterized in that... The high-speed camera is fixed in the center and faces the center of rotation, capturing the complete rotating body and the movement area of ​​the pendulum blocks.

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