阅读说明：本技术 一种运动态结构变形视觉测量方法 (Visual measurement method for deformation of dynamic structure ) 是由 唐小军 白宇君 田欣 于 2021-05-31 设计创作，主要内容包括：本发明涉及一种运动态结构变形视觉测量方法,属于运动态承载结构力学试验领域；提供了一种基于动态跟随、动态视觉测量技术的大视场、高精度、通用的运动态结构变形方法,适用于平移、升降、低速转动等运动工况条件下结构变形视觉测量,也适用于其他类似或静态条件下不同结构体变形视觉测量；主要解决航天、航空、船舶、重机等制造行业中大型复杂装备研制或者服役过程中运动态结构大视场变形困难的问题,有效解决了传统视觉测量无法与被测目标体随动,视场范围十分有限、对于大范围运动目标的捕获困难的难题。(The invention relates to a visual measurement method for deformation of a moving structure, belonging to the field of mechanical tests of moving bearing structures; the dynamic following and dynamic vision measurement technology-based large-view-field, high-precision and universal motion state structure deformation method is provided, and is suitable for structure deformation vision measurement under the motion working conditions of translation, lifting, low-speed rotation and the like, and is also suitable for deformation vision measurement of different structural bodies under other similar or static conditions; the method mainly solves the problem of difficult deformation of a large field of view of a moving structure in the development or service process of large-scale complex equipment in the manufacturing industries of aerospace, aviation, ships, heavy machinery and the like, and effectively solves the problems that the traditional vision measurement cannot follow a measured target body, the field of view is very limited, and the capture of the target moving in a large range is difficult.)

1. A visual measurement method for deformation of a moving structure is characterized by comprising the following steps: the method comprises the following steps:

step one, connecting an actuating mechanism (1) with a tested motion structure (2); the movement of the tested movement structure (2) is driven by the actuating mechanism (1);

secondly, pasting a visual measurement target (3) at a position where deformation measurement needs to be carried out on the surface of the measured motion structure (2); a real-time calibration ruler (4) is arranged in the middle of the measured motion structure (2);

thirdly, installing a pose tracking target (5) on the surface of the measured motion structure (2);

fourthly, connecting the root of the self-adaptive view field adjusting mechanism (12) with the mobile platform (13); a vision measurement high-stability base line structure (9) is arranged at the top of the self-adaptive view field adjusting mechanism (12); a first vision measuring head (7) is arranged at one end of a vision measuring high-stability base line structure (9), and a second vision measuring head (8) is arranged at the other end of the vision measuring high-stability base line structure (9); the first visual measuring head (7) and the second visual measuring head (8) are connected with a visual measuring control and processing system (11) through a visual measuring data transmission and control module (10); the first visual measuring head (7) and the second visual measuring head (8) are aligned with the measured motion structure (2);

fifthly, a pose tracking measurement module (6) is arranged in the middle of the vision measurement high-stability baseline structure (9); the pose tracking measurement module (6) is aligned to the measured motion structure (2), and the pose tracking measurement module (6) can capture a pose tracking target (5) in real time;

step six, adjusting the first visual measuring head (7) and the second visual measuring head (8) to realize that the first visual measuring head (7) and the second visual measuring head (8) can effectively cover all visual measuring targets (3); after the adjustment is finished, locking the positions of the first visual measuring head (7) and the second visual measuring head (8) to keep the relative poses of the first visual measuring head (7) and the second visual measuring head (8) stable;

controlling a first visual measuring head (7) and a second visual measuring head (8) to perform static state visual measurement and acquisition on the visual measuring targets (3) through a visual measurement control and processing system (11), and obtaining the real-time pose state of the measured moving structure (2) according to the absolute position and the relative position of each visual measuring target (3) distributed on the measured moving structure (2);

step eight, driving the tested motion structure (2) to move according to a preset track through the actuating mechanism (1);

controlling a first visual measuring head (7) and a second visual measuring head (8) to perform initial state visual measurement acquisition on a visual measuring target (3) through a visual measurement control and processing system (11), and calculating an initial state measurement image according to an acquisition result; carrying out equal deformation proportion calculation on the initial state measurement image; obtaining a corrected deformation measurement image, and obtaining a deformation measurement result of the current measured motion structure (2) according to the corrected deformation measurement image;

and step ten, repeating the step eight and the step nine, and averaging the deformation measurement results of the measured motion structure (2) to obtain the final deformation measurement result of the whole motion process of the measured motion structure (2).

2. The visual measurement method for the deformation of the dynamic structure according to claim 1, wherein: in the first step, the actuating mechanism (1) is an external actuating mechanism outside the measured moving structure (2) or an internal actuating mechanism carried by the measured moving structure (2).

3. The visual measurement method for the deformation of the dynamic structure according to claim 2, wherein: in the third step, the number of the pose tracking targets (5) is not less than 3, at least 1 pose tracking target (5) is arranged in the middle area of the measured motion structure (2), and the pose tracking targets (5) are not distributed on the same straight line.

4. A method according to claim 3, wherein the visual measurement of the deformation of the dynamic structure is as follows: in the fourth step, the visual measurement data transmission and control module (10) adopts a flexible data transmission line or a wireless data transmission mode to carry out data transmission and control; the vision measurement high-stability baseline structure (9) does not generate harmful deformation which affects the stability of the relative poses of the first vision measurement head (7) and the second vision measurement head (8) in motion.

5. The visual measurement method for the deformation of the dynamic structure according to claim 4, wherein: in the fifth step, the pose tracking measurement module (6) realizes that the accessory weight generated by the high-stability baseline structure (9) for vision measurement does not generate harmful deformation which affects the stability of the relative poses of the first vision measurement head (7) and the second vision measurement head (8).

6. The visual measurement method for the deformation of the dynamic structure according to claim 5, wherein: and seventhly, when the initial state vision measurement is collected, the collection frequency of the first vision measuring head (7) and the second vision measuring head (8) is 5-10 times of the maximum movement frequency of the measured movement structure (2).

7. The visual measurement method for the deformation of the dynamic structure according to claim 6, wherein: in the ninth step, a specific method for performing equal-proportion calculation on the initial state measurement image is as follows:

and calculating the deformation of the initial state measurement image according to the proportion of the actual length of the real-time scaling ruler (4) to the length in the image as a reference.

8. The visual measurement method for the deformation of the dynamic structure according to claim 7, wherein: in the ninth step, the lifting and the rotation of the mobile platform (13) are adjusted in real time according to the real-time pose data of the measured motion structure (2); by adjusting the translation of the adaptive field-of-view adjustment mechanism (12); and (3) realizing that the relative distance and relative attitude angle between the high-stability visual measurement baseline structure (9) and the measured motion structure (2) and the relative distance and relative attitude angle error of 2 in the step seven are kept within +/-2%.

9. The visual measurement method for the deformation of the dynamic structure according to claim 8, wherein: and the initial state vision measurement acquisition frequency in the ninth step is greater than the static state vision measurement acquisition frequency in the seventh step.

10. The visual measurement method for deformation of a dynamic structure according to claim 9, wherein: in the step ten, the step eight and the step nine are repeated not less than 10 times.

Technical Field

The invention belongs to the field of mechanical tests of a dynamic bearing structure, and relates to a dynamic structure deformation visual measurement method.

Background

Along with the rapid development of large-scale, complicated and multifunctional advanced equipment in the industries of aerospace, aviation, ships, heavy machinery and the like, various complex motion state bearing structure mechanisms are more and more widely applied, and in the development stage of the motion state bearing structure mechanisms of various complex equipment, the comprehensive mechanical examination and verification for simulating the actual use or service state of the complex equipment is particularly important, and the comprehensive mechanical examination and verification is directly related to the bearing capacity of the whole equipment and the reliability of the whole system. Taking space equipment as an example, as the space equipment develops towards space attack and defense, on-rail reconstruction and service and high-capacity communication, large space motion mechanisms such as large space folding and unfolding mechanisms, large-span mechanical arms and deployable antennas are increasingly widely applied to the space equipment. The structure is a key execution end of tasks such as space capture, butt joint and expansion, and in order to ensure the stability and reliability of the key operation of the large-scale space motion structure in a space complex environment, the structure must have enough mechanical properties such as strength and rigidity, and the mechanical properties directly determine the success or failure of the key operation task. The mechanical test verification and examination is an important means for guaranteeing that the structure successfully completes critical operation tasks in a complex service environment. Deformation is used as a core index for representing mechanical property, and the real-time accurate measurement of deformation parameters in ground mechanical test verification is the key for evaluating the structural properties.

The existing dynamic structure deformation methods mainly comprise a strain measurement method, a residual deformation measurement method and a conventional dynamic vision measurement method. The strain measurement method is characterized in that a strain sensor is adhered to the surface of a measured target, a strain measurement circuit is arranged, dynamic strain data of a measured dynamic structure mechanism are collected, and the deformation condition of a dynamic structure is obtained through reverse thrust of a deformation-strain relation; the method for measuring the residual deformation is mainly limited by the difficulty of dynamic measurement, the relative pose relation of main measured points of a measured target is measured by adopting a conventional static measurement means before and after the verification and the examination of a dynamic structure mechanical test are completed, and the residual deformation condition of the structure of the measured target after the dynamic mechanical test is obtained by comparing the measurement results before and after the test, but the method cannot measure the process state deformation condition, and the measurement result is only the residual deformation; however, the conventional dynamic vision measurement method usually adopts a dynamic vision measurement system, and directly captures the mark point of the measured target by means of a large-field image acquisition measuring head to acquire the dynamic deformation of the structure, but the method cannot follow the measured target, has a limited field range, is difficult to capture the target moving in a large range, and far cannot meet the measurement requirement of the deformation of the moving structure.

Disclosure of Invention

The technical problem solved by the invention is as follows: the method overcomes the defects of the prior art, provides a visual measurement method for the deformation of a moving structure, and effectively solves the problems that the traditional visual measurement cannot follow the measured target body, the field range is very limited, and the capture of the target moving in a large range is difficult.

The technical scheme of the invention is as follows:

a visual measurement method for deformation of a dynamic structure comprises the following steps:

step one, connecting an actuating mechanism with a tested motion structure; the measured motion structure is driven to move through the actuating mechanism;

secondly, pasting a visual measurement target at a position on the surface of the measured motion structure, where deformation measurement is needed; a real-time calibration scale is arranged in the middle of the measured motion structure;

thirdly, installing a pose tracking target on the surface of the measured motion structure;

connecting the root part of the self-adaptive view field adjusting mechanism with the mobile platform; installing a vision measurement high-stability base line structure at the top of the self-adaptive view field adjusting mechanism; a first vision measuring head is arranged at one end of the vision measuring high-stability base line structure, and a second vision measuring head is arranged at the other end of the vision measuring high-stability base line structure; the first visual measuring head and the second visual measuring head are both connected with the visual measuring control and processing system through a visual measuring data transmission and control module; the first visual measuring head and the second visual measuring head are both aligned to the measured motion structure;

fifthly, installing a pose tracking measurement module in the middle of the vision measurement high-stability baseline structure; the pose tracking measurement module is aligned to the measured motion structure, and the pose tracking measurement module is used for capturing a pose tracking target in real time;

step six, adjusting the first visual measuring head and the second visual measuring head to realize that the first visual measuring head and the second visual measuring head can effectively cover all visual measuring targets; after the adjustment is finished, locking the positions of the first vision measuring head and the second vision measuring head, and keeping the relative poses of the first vision measuring head and the second vision measuring head stable;

controlling the first vision measuring head and the second vision measuring head to perform static state vision measurement and acquisition on the vision measuring targets through the vision measurement control and processing system, and obtaining the real-time pose state of the measured moving structure according to the absolute position and the relative position of each vision measuring target distributed on the measured moving structure;

step eight, driving the tested motion structure to move according to a preset track through the actuating mechanism;

controlling the first vision measuring head and the second vision measuring head to perform initial state vision measurement and acquisition on the vision measuring target through the vision measurement control and processing system, and solving an initial state measurement image according to an acquisition result; carrying out equal deformation proportion calculation on the initial state measurement image; obtaining a corrected deformation measurement image, and obtaining a deformation measurement result of the current measured motion structure according to the corrected deformation measurement image;

and step ten, repeating the step eight and the step nine, and averaging the deformation measurement results of the measured motion structure to obtain the final deformation measurement result of the whole motion process of the measured motion structure.

In the above visual measurement method for deformation of a moving structure, in the first step, the actuating mechanism is an external actuating mechanism outside the moving structure to be measured, or an internal actuating mechanism carried by the moving structure to be measured.

In the third step, the number of the pose tracking targets is not less than 3, at least 1 pose tracking target is installed in the middle area of the measured moving structure, and the pose tracking targets are not distributed on the same straight line.

In the above visual measurement method for deformation of a moving structure, in the fourth step, the visual measurement data transmission and control module performs data transmission and control by using a flexible data transmission line or a wireless data transmission mode; the high-stability baseline structure for vision measurement does not generate harmful deformation which influences the stability of the relative poses of the first vision measuring head and the second vision measuring head in motion.

In the above method for measuring the deformation of the moving structure, in the fifth step, the pose tracking and measuring module does not generate harmful deformation that affects the stability of the relative poses of the first vision measuring head and the second vision measuring head on the weight of the accessories generated by the high-stability baseline structure for vision measurement.

In the above-mentioned visual measurement method for deformation of a moving structure, in the seventh step, when the initial state visual measurement is collected, the collection frequency of the first visual measurement head and the second visual measurement head is 5 to 10 times of the maximum movement frequency of the moving structure to be measured.

In the above-mentioned visual measurement method for deformation of a moving structure, in the ninth step, a specific method for performing equal-scale solution on an initial state measurement image is as follows:

and calculating the deformation of the initial state measurement image according to the proportion by taking the proportion of the real-time scaling actual length to the length in the image as a reference.

In the visual measurement method for the deformation of the motion state structure, in the ninth step, the lifting and the rotation of the mobile platform are adjusted in real time according to the real-time pose data of the measured motion structure; adjusting the translation of the adaptive view field adjusting mechanism; and (3) the relative distance and relative attitude angle between the high-stability baseline structure and the measured motion structure in the vision measurement and the relative distance and relative attitude angle error of the 2 in the step seven are kept within +/-2%.

In the above method for visually measuring deformation of a moving structure, the acquisition frequency of the initial state visual measurement in the ninth step is greater than the acquisition frequency of the static state visual measurement in the seventh step.

In the above-mentioned visual measurement method for deformation of a dynamic structure, in the step ten, the step eight and the step nine are repeated not less than 10 times.

Compared with the prior art, the invention has the beneficial effects that:

(1) the invention provides a dynamic following, non-contact, large-view-field, high-precision and universal motion state structure deformation method, which can solve the problem that large-scale complex equipment in the manufacturing industries such as aerospace, aviation, ships, heavy machinery and the like is difficult to deform in a large view field of a motion state structure in the service process, and can realize high-precision deformation measurement on a motion state structure;

(2) the invention adopts the self-adaptive visual field adjusting mechanism and the mobile platform design method, realizes the problem of dynamic following of the conventional visual measurement visual field in the movement process of the measured target body, and effectively solves the problems that the traditional visual measurement cannot follow the measured target body, the visual field range is very limited, and the capture of the target moving in a large range is difficult;

(3) the invention adopts a high-stability baseline structure for vision measurement and a movement baseline design, realizes the stability of the relative pose of the vision measuring head in the movement state measuring process, and innovatively realizes the movement structure deformation measurement under the condition of the movement measurement baseline.

Drawings

FIG. 1 is a schematic view of a dynamic structural deformation vision measuring system according to the present invention.

Detailed Description

The invention is further illustrated by the following examples.

The invention provides a visual measurement method for deformation of a moving structure, which is a large-view-field, high-precision and universal moving structure deformation method based on dynamic following and dynamic visual measurement technologies and mainly solves the problem of difficulty in large-view-field deformation of the moving structure in the development or service process of large-scale complex equipment in the manufacturing industries of aerospace, aviation, ships, heavy machinery and the like.

The dynamic structure deformation visual measurement method specifically comprises the following steps:

step one, connecting an actuating mechanism 1 with a tested motion structure 2; the measured motion structure 2 is driven to move through the actuating mechanism 1. In the design, the actuating mechanism 1 may be an external actuating mechanism other than the measured moving structure 2 or an internal actuating mechanism carried by the measured moving structure 2 according to the actual requirement or the actual space size, as shown in fig. 1.

Secondly, pasting a visual measurement target 3 at a position on the surface of the measured motion structure 2 where deformation measurement is needed; and a real-time calibration ruler 4 is arranged in the middle of the measured moving structure 2.

Thirdly, installing a pose tracking target 5 on the surface of the measured motion structure 2; the number of the pose tracking targets 5 is not less than 3, at least 1 pose tracking target 5 is arranged in the middle area of the measured moving structure 2, and the pose tracking targets 5 are not distributed on the same straight line.

Step four, connecting the root of the self-adaptive view field adjusting mechanism 12 with the mobile platform 13; a vision measurement high-stability baseline structure 9 is arranged at the top of the self-adaptive view field adjusting mechanism 12; a first vision measuring head 7 is arranged at one end of a vision measuring high-stability baseline structure 9, and a second vision measuring head 8 is arranged at the other end of the vision measuring high-stability baseline structure 9; the first visual measuring head 7 and the second visual measuring head 8 are both connected with a visual measuring control and processing system 11 through a visual measuring data transmission and control module 10; the first visual measuring head 7 and the second visual measuring head 8 are both aligned with the measured motion structure 2; the vision measurement data transmission and control module 10 adopts a flexible data transmission line or a wireless data transmission mode to carry out data transmission and control; the vision measurement high-stability baseline structure 9 does not generate harmful deformation which affects the relative pose stability of the first vision measuring head 7 and the second vision measuring head 8 in motion.

When the vision measuring head is installed, the first vision measuring head 7 and the second vision measuring head 8 are respectively installed at two ends of the vision measuring high-stability baseline structure and are connected with the control module and the vision measuring control and processing system through the vision measuring data transmission to form a dynamic vision measuring loop.

Fifthly, installing a pose tracking measurement module 6 in the middle of the vision measurement high-stability baseline structure 9; the pose tracking measurement module 6 is aligned to the measured motion structure 2, and the pose tracking measurement module 6 is used for capturing a pose tracking target 5 in real time; the pose tracking measurement module 6 realizes that the accessory weight generated by the high-stability baseline structure 9 for vision measurement does not generate harmful deformation which affects the relative pose stability of the first vision measurement head 7 and the second vision measurement head 8.

The absolute position of a pose tracking target 5 arranged on the measured moving structure and the relative pose relation of tracking targets with different poses are measured in real time through a pose tracking measurement module 6, the real-time pose state of the measured moving structure 2 is obtained, and meanwhile, the pose adjustment of a vision measurement high-stability baseline structure 9 arranged at the top end of an adaptive view field adjusting mechanism 12 is realized through the real-time lifting, translation and rotation of the adaptive view field adjusting mechanism 12 and a moving platform 13.

Step six, adjusting the first vision measuring head 7 and the second vision measuring head 8 to realize that the first vision measuring head 7 and the second vision measuring head 8 can effectively cover all vision measuring targets 3; after the adjustment is completed, the positions of the first vision measuring head 7 and the second vision measuring head 8 are locked, and the relative poses of the first vision measuring head 7 and the second vision measuring head 8 are kept stable.

And debugging the tested target module, the dynamic vision measuring module and the dynamic following module in sequence to ensure that the tested target module, the dynamic vision measuring module and the dynamic following module can work normally.

And (5) carrying out system calibration. The measured motion structure 2 is moved to the initial measurement state through the operation of the actuating mechanism 1; furthermore, the position and pose tracking measurement module is calibrated before measurement according to the actual installation position of the pose tracking target 5. Further, the dynamic vision measurement module is calibrated by adopting a vision measurement calibration ruler 4. In the dynamic vision measurement module calibration process, the vision measurement calibration ruler is placed at the position near the installation of different vision measurement targets during actual measurement, and at least 20 calibration images are acquired.

Controlling a first vision measuring head 7 and a second vision measuring head 8 to perform static state vision measurement and acquisition on the vision measuring targets 3 through a vision measurement control and processing system 11, and obtaining the real-time pose state of the measured moving structure 2 according to the absolute position and the relative position of each vision measuring target 3 distributed on the measured moving structure 2; when the vision measurement is collected in the initial state, the collection frequency of the first vision measuring head 7 and the second vision measuring head 8 is 5-10 times of the maximum movement frequency of the measured movement structure 2.

And step eight, driving the tested motion structure 2 to move according to a preset track through the actuating mechanism 1.

Controlling the first vision measuring head 7 and the second vision measuring head 8 to perform initial state vision measurement acquisition on the vision measuring target 3 through the vision measurement control and processing system 11, and calculating an initial state measurement image according to an acquisition result; carrying out equal deformation proportion calculation on the initial state measurement image; obtaining a corrected deformation measurement image, and obtaining a deformation measurement result of the current motion structure 2 to be measured according to the corrected deformation measurement image; the specific method for carrying out equal-proportion calculation on the initial state measurement image comprises the following steps: and calculating the deformation of the initial state measurement image according to the proportion of the actual length of the real-time scaling ruler 4 to the length in the image as a reference.

In the ninth step, the lifting and the rotation of the mobile platform 13 are adjusted in real time according to the real-time pose data of the detected motion structure 2; by adjusting the translation of the adaptive field-of-view adjustment mechanism 12; and (3) realizing that the relative distance and relative attitude angle between the high-stability visual measurement baseline structure 9 and the measured moving structure 2 and the relative distance and relative attitude angle error between the high-stability visual measurement baseline structure and the measured moving structure 2 in the step seven are kept within +/-2%. And the initial state vision measurement acquisition frequency is greater than the static state vision measurement acquisition frequency in the step seven.

And step ten, repeating the step eight and the step nine no less than 10 times. And averaging the deformation measurement results of the measured moving structure 2 to obtain the final deformation measurement result of the whole moving process of the measured moving structure 2.

The principle of the invention is as follows:

the motion of the measured motion structure 2 is realized through the actuating mechanism 1, and the real-time pose adjustment of the high-stability visual measurement baseline structure 9 is realized through a dynamic following module consisting of a pose tracking target 5, a pose tracking measurement module 6, a self-adaptive view field adjusting mechanism 12 and a mobile platform 13, so that the effective real-time coverage of the measurement view field of the measured motion structure 2 by the dynamic visual measurement module is realized. The relative position information between different vision measurement targets of a measured motion structure is acquired in real time through a dynamic vision measurement loop consisting of a vision measurement target 3, a real-time calibration scale 4, a first vision measurement head 7, a second vision measurement head 8, a vision measurement high-stability baseline structure 9, a vision measurement data transmission and control module 10 and a vision measurement control and processing system 11, and then the relative position information is converted through a unified coordinate system and is compared with an initial state measurement result for resolving, so that the real-time measurement of the deformation of the motion structure is finally realized.

The invention relates to a dynamic following, non-contact, large-view-field, high-precision and universal motion state structure deformation method, which can solve the problem of difficult large-view-field deformation of a motion state structure in the development or service process of large-scale complex equipment in the manufacturing industries of aerospace, aviation, ships, heavy machinery and the like, and can realize high-precision deformation measurement on a motion state structure mechanism. By adopting the self-adaptive visual field adjusting mechanism and the mobile platform design method, the problem of dynamic following of the conventional visual measurement visual field in the movement process of the measured target body is solved, and the problems that the conventional visual measurement cannot follow the measured target body, the visual field range is very limited and the target moving in a large range is difficult to capture are effectively solved. In addition, the invention adopts a high-stability baseline structure for vision measurement and a movement baseline design, realizes the stability of the relative pose of the vision measuring head in the movement state measuring process, and innovatively realizes the movement structure deformation measurement under the condition of the movement measuring baseline.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make variations and modifications of the present invention without departing from the spirit and scope of the present invention by using the methods and technical contents disclosed above.