A target point accurate positioning and large workpiece measuring device and a measuring method thereof

Abstract

The application discloses a target point accurate positioning and large workpiece measuring device and a measuring method thereof. The motion range adjusting part is used for adjusting the position of the measuring point in a large range, controlling the movement of the measuring device, and making the measuring device reach a general direction suitable for the operation of the camera group; the angle adjusting part is used for adjusting the working visual angle of the device in 360 degrees; the vertical displacement adjusting part is used for calibrating target points of different heights; and the horizontal displacement adjusting part is used for controlling the movement range of the camera group, so as to improve the measuring precision. The application solves the problems of difficult initial calibration and low precision in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of measurement technology, specifically relating to a device and method for precise positioning of target points and measurement of large workpieces. Background Technology

[0002] Existing positioning methods can be broadly categorized into two types: relative positioning and absolute positioning. Relative positioning systems achieve positioning by measuring the moving object's position relative to an initial position. Their main characteristic is that long-term positioning errors accumulate significantly, making them unsuitable for precise positioning. Absolute positioning systems, on the other hand, achieve positioning based on the absolute position of the moving object, primarily relying on sonar, visual sensors, etc. Absolute positioning offers higher accuracy and can also be used to correct errors in relative positioning systems. Its main drawback is its relatively complex implementation. Currently common spatial positioning technologies include mechanical positioning, infrared (optical) positioning, electromagnetic positioning, ultrasonic positioning, vision sensor-based positioning, and hybrid inertial positioning. Among these, the most widely used are:

[0003] 1. Mechanical Positioning: Mechanical positioning utilizes various mechanical devices and sensors to obtain the position and angle of the object being measured; it is a relative positioning method. Mechanical positioning requires no special calculations to determine the camera's position, and the tracking data has almost no delay; the camera's position parameters are very accurate; and no additional workstation is needed to process the tracking information. Disadvantages include: limitations on the types and number of cameras that can be used, and the inability to use handheld cameras; the need to install sensors on each camera, resulting in high installation costs and inconvenience; the bulky and cumbersome mechanical tracking system of the camera, increasing the difficulty for participants to use flexibly; the need for precise measurement and calibration of the camera lens before shooting; and the time-consuming process of obtaining the camera's initial position and orientation before shooting.

[0004] 2. Infrared Positioning: Infrared positioning requires an infrared camera that can emit and receive infrared light, positioned in a world coordinate system and aimed at a target. An infrared reflector sphere must also be mounted on top of the camera. The position and orientation of the camera are determined by processing the reflected infrared light. This is an absolute positioning method. The advantages of infrared positioning are: high infrared propagation speed, resulting in a high update rate and low latency; a large working range; and minimal susceptibility to lighting conditions. The disadvantages are: infrared positioning is based on triangulation, therefore, there must be no obstruction between the target and the reflector sphere.

[0005] 3. Vision Sensor-Based Positioning: This method utilizes the relationship between camera image pixel positions and scene point positions. Based on the camera model, it solves for the camera's position in the world coordinate system using the image coordinates of known feature points and world coordinates; or it performs a series of geometric or other operations on the image to obtain the camera's three-dimensional position information, making it an absolute positioning method. The advantages of vision sensor-based positioning are: simplicity, practicality, wide applicability, and relatively convenient installation; portable cameras can be used directly; and the camera can move without a track. However, this technology also has some disadvantages: the computer needs to match the physical coordinates of the points on the template with the corresponding points in the template image, resulting in long data processing time and a certain positioning delay; the camera must capture the template image, so the template cannot be completely blocked during positioning, and the coordinates of the reference points must be accurately known; the image clarity is relatively low, so the positioning accuracy of this camera positioning method is not particularly high; and marking reference points within the template is not an easy task.

[0006] In summary, mechanical positioning methods involve complex equipment and difficult initial calibration. Methods based on vision sensors lack sufficient accuracy. Summary of the Invention

[0007] This invention provides a device and method for precise positioning of target points and measurement of large workpieces, which solves the problems of difficult initial calibration and low accuracy in the prior art.

[0008] This invention is achieved through the following technical solution:

[0009] A device for precise positioning of target points and measurement of large workpieces, the measuring device comprising a motion range adjustment section, an angle adjustment section, a vertical displacement adjustment section, and a horizontal displacement adjustment section;

[0010] The motion range adjustment unit is used to adjust the position of the measuring point over a wide range and control the movement of the measuring device to reach a suitable approximate position for the camera group's operation.

[0011] The angle adjustment unit is used to adjust the working angle of the device 360 ​​degrees.

[0012] The vertical displacement adjustment unit is used to calibrate target points at different heights;

[0013] The lateral displacement adjustment unit is used to control the movement range of the camera group, thereby improving its measurement accuracy.

[0014] A target point precise positioning and large workpiece measuring device, wherein an angle adjustment part is provided on the upper surface of the motion range adjustment part, a vertical displacement adjustment part is provided at the top of the angle adjustment part, and a horizontal displacement adjustment part is provided on the vertical displacement adjustment part, and the target point is precisely positioned by the camera (7) and camera (8) of the horizontal displacement adjustment part.

[0015] A device for precise target point positioning and large workpiece measurement, wherein the motion range adjustment unit includes a vehicle-mounted work platform 1, the angle adjustment unit includes a rotary platform 2, and the vertical displacement adjustment unit includes a lifting mechanism 3.

[0016] A rotating platform 2 is installed at the top of the vehicle-mounted work platform 1, and a lifting mechanism 3 is installed at the center of the rotating platform 2.

[0017] A device for precise positioning of target points and measurement of large workpieces, wherein the lateral displacement adjustment part includes a horizontal moving mechanism 4, a fixed support 5, a camera turntable 6, a camera 7, a camera 8, a camera turntable 9, and a moving support 10;

[0018] A fixed bracket 5 is provided at one end of the horizontal moving mechanism 4, a camera turntable I6 is provided at the upper end of the fixed bracket 5, and a camera I7 is provided at the upper end of the camera turntable I6.

[0019] The horizontal moving mechanism 4 is slidably connected to the moving bracket 10, the moving bracket 10 is provided with a camera turntable II 9, and the upper end of the camera turntable II 9 is provided with a camera II 8.

[0020] A device for precise positioning of target points and measurement of large workpieces, wherein a lifting motor is provided at the bottom of the lifting mechanism 3 for controlling the lifting of the horizontal moving mechanism 4 in the lateral displacement adjustment section.

[0021] A measurement method for a target point precise positioning and large workpiece measuring device, the measurement method comprising the following steps:

[0022] Step 1: Assemble the measuring device as described in claim 1;

[0023] Step 2: Determine the location of the target point and adjust the range of motion to be near the target point, i.e., the approximate location suitable for the camera group's operation;

[0024] Step 3: Use the angle adjustment unit to ensure that camera I7 and camera II8 are facing the target being measured;

[0025] Step 4: Control the vertical displacement adjustment unit to adjust cameras I7 and II8 to the same height as the target being measured;

[0026] Step 5: Control the angle and position of camera I7 and camera II8 in the lateral adjustment section to ensure that they are on the same horizontal plane as the target point being measured;

[0027] Step 6: Based on the horizontal plane adjusted in Step 5, establish a coordinate system to obtain the relative positional relationship between the measuring device and the target point, thereby realizing the measurement of large workpieces.

[0028] A measurement method for a target point precise positioning and large workpiece measuring device, wherein step 2 specifically involves controlling the rotary platform 2 to rotate by a certain angle so that the camera lens faces the target point, and the rotation angle of the rotary platform can be obtained by an absolute encoder.

[0029] Specifically, step 3 involves controlling the lifting mechanism 3 to raise the camera on the horizontal moving mechanism 4 to the same height as the target point, and the height of the horizontal moving mechanism 4 can be obtained through an absolute encoder.

[0030] Specifically, step 4 involves moving the position of camera 8 using the horizontal moving mechanism 4, thereby adjusting the distance between the two cameras. The distance between camera 7 and camera 8 can be obtained using an absolute encoder.

[0031] A measurement method for a target point precise positioning and large workpiece measuring device, wherein step 5 specifically involves obtaining the rotation angle through an absolute encoder: controlling the camera turntable 9 to rotate so that the target point is imaged on the center point of the camera 8, thereby obtaining the angle between the center line of the camera 8 and the horizontal moving mechanism 4; similarly, controlling the camera turntable 6 to rotate so that the target point is imaged on the center point of the camera 7, thereby obtaining the angle between the center line of the camera 7 and the horizontal moving mechanism 4.

[0032] A measurement method for a target point precise positioning and large workpiece measuring device, wherein step 6 specifically involves the center points of cameras 7 and 8 being on the same horizontal plane as the target point and forming a triangle, and the distance between the target point and the horizontal moving mechanism 4 being calculated according to the measurement principle.

[0033] Determine the coordinates of the target point in the coordinate system of the large workpiece measuring device;

[0034] By obtaining the relative positional relationship between the robot and the workpiece, precise positioning of the target point was achieved.

[0035] A measurement method for a target point precise positioning and large workpiece measuring device, wherein the measurement principle is as follows: the target point is P, O1 is the optical center of camera 1, and O2 is the optical center of camera 2. O1P is perpendicular to the plane where the lens of camera 1 is located, and O2P is perpendicular to the plane where the lens of camera 2 is located. It is known that the length of the baseline O1O2 where the two camera lenses are located is L, and the angle between O1P and O1O2 is α, the angle between O2P and O1O2 is β, and the distance between the target point P and O1O2 is h;

[0036] The relationship between the distance h between the target point and the baseline and the baseline length L is as follows:

[0037] L=h(ctgα+ctgβ)

[0038] The distance h between the target point P and O1O2 can be obtained using the above formula.

[0039] The beneficial effects of this invention are:

[0040] This invention has the advantages of being simple, quick, and highly accurate.

[0041] This invention not only overcomes the difficulty of ensuring accuracy in long-distance camera measurements, but also provides a mobile measuring device with high measurement accuracy, saving efficiency and improving production efficiency. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the structure of the present invention.

[0043] Figure 2 This is a schematic diagram of the present invention. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] This invention is used to capture and locate target points when using 3D laser projection technology to assist in the processing of large workpieces. The data is then transmitted to a computer to determine the projection robot's posture and adjust projection information, resulting in accurate projection of the image to be processed. Two cameras are fixed to an angle-adjustable support frame. One set is fixed to the worktable, and the other is placed on a ball screw on the worktable, using the ball screw as a guide to change the distance between the camera lenses. The rotational displacement of camera turntables 6 and 9 is measured using a high-bit absolute encoder. The lifting mechanism 3 and the horizontal movement mechanism 4 both use ball screw mechanisms, and their linear displacement is measured using a high-bit absolute encoder. The high-bit absolute encoder needs to be connected to the output shaft of the drive motor of the mechanism to measure the linear or rotational displacement of the mechanism. Cameras 7 and 8 must be installed at the same height.

[0046] A device for precise positioning of target points and measurement of large workpieces, the measuring device comprising a motion range adjustment section, an angle adjustment section, a vertical displacement adjustment section, and a horizontal displacement adjustment section;

[0047] The motion range adjustment unit is used to adjust the position of the measuring point over a wide range and control the movement of the measuring device to reach a suitable approximate position for the camera group's operation.

[0048] The angle adjustment unit is used to adjust the working angle of the device 360 ​​degrees.

[0049] The vertical displacement adjustment unit is used to calibrate target points at different heights;

[0050] The lateral displacement adjustment unit is used to control the movement range of the camera group, thereby improving its measurement accuracy.

[0051] The motion range adjustment unit includes a vehicle-mounted work platform 1, wheels I 11, II 12, III 13 and IV 14, which are used for movement.

[0052] The vehicle-mounted work platform 1 provides stable support for the angle adjustment section, the vertical displacement adjustment section, and the lateral displacement adjustment section.

[0053] A target point precise positioning and large workpiece measuring device, wherein an angle adjustment part is provided on the upper surface of the motion range adjustment part, a vertical displacement adjustment part is provided at the top of the angle adjustment part, and a horizontal displacement adjustment part is provided on the vertical displacement adjustment part, and the target point is precisely positioned by the camera (7) and camera (8) of the horizontal displacement adjustment part.

[0054] A device for precise positioning of target points and measurement of large workpieces, wherein the motion range adjustment unit includes a vehicle-mounted work platform 1, the angle adjustment unit includes a rotary platform 2, the vertical displacement adjustment unit includes a lifting mechanism 3, the rotary platform 2 is provided at the top of the vehicle-mounted work platform 1, and the lifting mechanism 3 is provided at the center of the rotary platform 2.

[0055] A device for precise positioning of target points and measurement of large workpieces, wherein the lateral displacement adjustment part includes a horizontal moving mechanism 4, a fixed support 5, a camera turntable 6, a camera 7, a camera 8, a camera turntable 9, and a moving support 10;

[0056] A fixed bracket 5 is provided at one end of the horizontal moving mechanism 4, a camera turntable I6 is provided at the upper end of the fixed bracket 5, and a camera I7 is provided at the upper end of the camera turntable I6.

[0057] The horizontal moving mechanism 4 is slidably connected to the moving bracket 10, the moving bracket 10 is provided with a camera turntable II 9, and the upper end of the camera turntable II 9 is provided with a camera II 8.

[0058] A device for precise positioning of target points and measurement of large workpieces, wherein a lifting motor is provided at the bottom of the lifting mechanism 3 to control the lifting of the horizontal moving mechanism 4 in the lateral displacement adjustment section, and the control range is the length of the movable part of the entire lifting track.

[0059] A measurement method for a target point precise positioning and large workpiece measuring device, the measurement method comprising the following steps:

[0060] Step 1: Assemble the measuring device as described in claim 1;

[0061] Step 2: Determine the location of the target point and adjust the range of motion to be near the target point, i.e., the approximate location suitable for the camera group's operation;

[0062] Step 3: Use the angle adjustment unit to ensure that camera I7 and camera II8 are facing the target being measured;

[0063] Step 4: Control the vertical displacement adjustment unit to adjust cameras I7 and II8 to the same height as the target being measured;

[0064] Step 5: Control the angle and position of camera I7 and camera II8 in the lateral adjustment section to ensure that they are on the same horizontal plane as the target point being measured;

[0065] Step 6: Based on the horizontal plane adjusted in Step 5, establish a coordinate system to obtain the relative positional relationship between the measuring device and the target point, thereby realizing the measurement of large workpieces.

[0066] The absolute encoder is usually installed at the tail of the drive unit. For example, when measuring the speed of a DC motor, the encoder is connected to the tail shaft of the motor.

[0067] A measurement method for a target point precise positioning and large workpiece measuring device, wherein step 2 specifically involves controlling the rotary platform 2 to rotate by a certain angle so that the camera lens faces the target point, and the rotation angle of the rotary platform can be obtained by an absolute encoder.

[0068] Specifically, step 3 involves controlling the lifting mechanism 3 to raise the camera on the horizontal moving mechanism 4 to the same height as the target point, and the height of the horizontal moving mechanism 4 can be obtained through an absolute encoder.

[0069] Specifically, step 4 involves moving the position of camera 8 using the horizontal moving mechanism 4, thereby adjusting the distance between the two cameras. The distance between camera 7 and camera 8 can be obtained using an absolute encoder.

[0070] A measurement method for a target point precise positioning and large workpiece measuring device, wherein step 5 specifically involves obtaining the rotation angle through an absolute encoder: controlling the camera turntable 9 to rotate so that the target point is imaged on the center point of the camera 8, that is, the optical center of the camera 8 is directly facing the target point, thereby obtaining the angle between the center line of the camera 8 and the horizontal moving mechanism 4; similarly, controlling the camera turntable 6 to rotate so that the target point is imaged on the center point of the camera 7, thereby obtaining the angle between the center line of the camera 7 and the horizontal moving mechanism 4.

[0071] 9. The measurement method of the target point precise positioning and large workpiece measuring device according to claim 8, wherein step 6 specifically involves the center points of camera 7 and camera 8 being on the same horizontal plane as the target point and forming a triangle, and the distance between the target point and the horizontal moving mechanism 4 being calculated according to the measurement principle;

[0072] Determine the coordinates of the target point in the coordinate system of the large workpiece measuring device;

[0073] By obtaining the relative positional relationship between the robot and the workpiece, precise positioning of the target point was achieved.

[0074] A measurement method for a target point precise positioning and large workpiece measuring device, wherein the measurement principle is as follows: the target point is P, O1 is the optical center of camera 1, and O2 is the optical center of camera 2. O1P is perpendicular to the plane where the lens of camera 1 is located, that is, the optical center O1 of camera 1 is directly facing the target point P. Similarly, O2P is perpendicular to the plane where the lens of camera 2 is located, that is, the optical center O2 of camera 2 is directly facing the target point P. It is known that the length of the baseline O1O2 where the two camera lenses are located is L, and the angle between O1P and O1O2 is α, the angle between O2P and O1O2 is β, and the distance between the target point P and O1O2 is h;

[0075] The relationship between the distance h between the target point and the baseline and the baseline length L is as follows:

[0076] L=h(ctgα+ctgβ)

[0077] The distance h between the target point P and O1O2 can be obtained using the above formula.

Claims

1. A measurement method for a target point precise positioning and large workpiece measuring device, characterized in that, The measuring device includes a motion range adjustment section, an angle adjustment section, a vertical displacement adjustment section, and a lateral displacement adjustment section; The motion range adjustment unit is used to adjust the position of the measuring point over a wide range and control the movement of the measuring device to reach a suitable approximate position for the camera group's operation. The angle adjustment unit is used to adjust the working angle of the device 360 ​​degrees. The vertical displacement adjustment unit is used to calibrate target points at different heights; The lateral displacement adjustment unit is used to control the movement range of the camera group, thereby improving its measurement accuracy; The motion range adjustment unit includes a vehicle-mounted work platform (1), the angle adjustment unit includes a rotary platform (2), and the vertical displacement adjustment unit includes a lifting mechanism (3). A rotating platform (2) is provided at the top of the vehicle-mounted work platform (1), and a lifting mechanism (3) is provided at the center of the rotating platform (2). The lateral displacement adjustment unit includes a horizontal moving mechanism (4), a fixed bracket (5), a camera turntable (6), a camera (7), a camera (8), a camera turntable (9), and a moving bracket (10). A fixed bracket (5) is provided at one end of the horizontal moving mechanism (4), a camera turntable I (6) is provided at the upper end of the fixed bracket (5), and a camera I (7) is provided at the upper end of the camera turntable I (6). The horizontal moving mechanism (4) is slidably connected to the moving bracket (10), the moving bracket (10) is provided with the camera turntable II (9), and the camera II (8) is provided at the upper end of the camera turntable II (9). The bottom end of the lifting mechanism (3) is equipped with a lifting motor, which is used to control the lifting of the horizontal moving mechanism (4) in the lateral displacement adjustment part; The measurement method includes the following steps: Step 1: Determine the location of the target point for measuring the large workpiece, and control the motion range adjustment unit to be near the target point, i.e., the approximate location suitable for the camera group's operation; Step 2: Control the angle adjustment unit to ensure that camera I (7) and camera II (8) are facing the target being measured; Step 3: Control the vertical displacement adjustment unit to adjust camera I (7) and camera II (8) to the same height as the target being measured; Step 4: Control the angle and position of camera I (7) and camera II (8) in the lateral adjustment section to ensure that they are on the same horizontal plane as the target point being measured; Specifically, step 4 involves obtaining the rotation angle using an absolute encoder: controlling the camera turntable (9) to rotate so that the target point is imaged on the center point of camera II (8), thus obtaining the angle between the center line of camera II (8) and the horizontal moving mechanism (4); similarly, controlling the camera turntable (6) to rotate so that the target point is imaged on the center point of camera I (7), thus obtaining the angle between the center line of camera I (7) and the horizontal moving mechanism (4); Step 5: Based on the horizontal plane adjusted in Step 4, establish a coordinate system to obtain the relative positional relationship between the measuring device and the target point, thereby realizing the measurement of large workpieces; Specifically, step 5 involves the center points of camera I (7) and camera II (8) being on the same horizontal plane as the target point and forming a triangle. Based on the measurement principle, the distance between the target point and the horizontal moving mechanism (4) is calculated. Determine the coordinates of the target point in the coordinate system of the large workpiece measuring device; By obtaining the relative positional relationship between the robot and the workpiece, precise positioning of the target point was achieved.

2. The measurement method according to claim 1, characterized in that, An angle adjustment part is provided on the upper surface of the motion range adjustment part, a vertical displacement adjustment part is provided at the top of the angle adjustment part, and a horizontal displacement adjustment part is provided on the vertical displacement adjustment part. The target point is accurately positioned by the camera (7) and camera (8) of the horizontal displacement adjustment part.

3. The measurement method according to claim 1, characterized in that, Step 2 specifically involves controlling the rotary platform (2) to rotate at a certain angle so that the camera lens faces the target point. The rotation angle of the rotary platform can be obtained through an absolute encoder. Specifically, step 3 involves controlling the lifting mechanism (3) to raise the camera on the horizontal moving mechanism (4) to the same height as the target point, and obtaining the height of the horizontal moving mechanism (4) through an absolute encoder. Specifically, step 4 involves moving the position of camera II (8) using the horizontal moving mechanism (4) to adjust the distance between the two cameras. The distance between camera I (7) and camera II (8) can be obtained through the absolute encoder.

4. The measurement method according to claim 1, characterized in that, The measurement principle is as follows: the target point is P, O1 is the optical center of camera I (7), and O2 is the optical center of camera 2; O1P is perpendicular to the plane where the lens of camera I (7) is located, and O2P is perpendicular to the plane where the lens of camera II (8) is located. It is known that the length of the baseline O1O2 where the lenses of the two cameras are located is L, and the angle between O1P and O1O2 is α, the angle between O2P and O1O2 is β, and the distance between the target point P and O1O2 is h. The relationship between the distance h between the target point and the baseline and the baseline length L is as follows: The distance h between the target point P and O1O2 can be obtained using the above formula.

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