阅读说明：本技术 起重机吊钩/吊物旋角检测方法、误差消除方法及系统 (Crane hook/hanging object rotation angle detection method, error elimination method and system ) 是由 谭建平 梁高震 冯玮耀 甘小双 于 2021-06-24 设计创作，主要内容包括：本发明公开了一种起重机吊钩/吊物旋角检测方法、误差消除方法及系统,其中检测方法包括：获取实时标志物图像；对实时标志物图像进行预处理,建立标志物图像直角坐标系,获取每个光源光斑的实时圆心坐标,求取所有光源光斑的实时圆心坐标的平均值A-i；并基于三点共圆的方法求取标志物上N个光源的共圆实时圆心坐标D-i,得到实时位置向量获取预设的起始位置向量基于实时位置向量和起始位置向量得到自旋角度α。本发明方案简单可靠,检测精度高,为自旋控制提供理论技术支持,并可以提高吊钩/吊物摆动角度检测的精度。(The invention discloses a method for detecting a rotation angle of a crane hook/a hanging object, an error eliminating method and a system, wherein the detection method comprises the following steps: acquiring a real-time marker image; preprocessing a real-time marker image, establishing a marker image rectangular coordinate system, acquiring the real-time circle center coordinate of each light source light spot, and calculating the average value A of the real-time circle center coordinates of all the light source light spots i (ii) a And the co-circle real-time circle center coordinate D of N light sources on the marker is solved based on a three-point co-circle method i To obtain a real-time position vector Obtaining a preset initial position vector Based on real-time position vectors And a starting position vector The spin angle α is obtained. The invention has simple and reliable scheme and high detection precision, provides theoretical technical support for spin control and can improve the precision of the detection of the swing angle of the lifting hook/the hanging object.)

1. A method for detecting the rotation angle of a crane hook/hanging object is characterized by comprising the following steps:

acquiring a real-time marker image; the marker is horizontally arranged on the upper surface of the lifting hook, N light sources are arranged on the same circumference of the upper surface of the marker, and N is more than or equal to 3; the real-time marker image is acquired by an image acquisition device arranged above the marker;

preprocessing a real-time marker image, establishing a marker image rectangular coordinate system, acquiring the real-time circle center coordinate of each light source light spot, and calculating the average value A of the real-time circle center coordinates of all the light source light spots_i(ii) a And the co-circle real-time circle center coordinate D of N light sources on the marker is solved based on a three-point co-circle method_iTo obtain a real-time position vector

Obtaining a preset initial position vector

Based on real-time position vectorsAnd a starting position vectorThe resulting spin angle α is:

2. the crane hook/pendant swing angle detection method according to claim 1, wherein said preprocessing comprises:

carrying out noise reduction processing on the real-time marker image;

processing the denoised real-time marker image by adopting an edge detection algorithm to obtain a light source light spot profile corresponding to each light source;

processing the outline of each light source light spot by adopting a connected domain function to obtain the circle center coordinate d of each light source light spot_i(x_i,y_i)(i＝1,2,…,N)。

3. The crane hook/pendant swing angle detection method according to claim 2, wherein said noise reduction process comprises: selecting a cross-shaped structural element, performing opening operation of morphological processing on the original image, and removing a fine area with higher brightness in a light source spot of the original image;

when a plurality of circle centers corresponding to the light source light spot profiles are processed by adopting the connected domain function, one circle center is randomly reserved, and other coordinates are removed.

4. The crane hook/pendant rotation angle detection method of claim 1, wherein said three point co-circularization based method finds N lights on a markerSource co-circular real-time circle center coordinates D_iThe method specifically comprises the following steps:

based on the method of three-point co-circle, the centers of the three-point co-circle of the N light sources are co-circleTo obtainCircle center coordinate D'_jThe mean value of the two-dimensional data is used for obtaining a co-circle real-time circle center coordinate D_i：

5. A crane hook/sling rotation angle detection method as claimed in any one of claims 1 to 4, wherein said predetermined start position vectorObtained by the following method:

acquiring an initial marker image;

preprocessing the initial marker image, establishing a rectangular coordinate system of the marker image, acquiring the initial circle center coordinate of each light source light spot, and simultaneously calculating the average value A of the initial circle center coordinates of all the light source light spots₀(ii) a And the coordinate D of the concentric initial circle center of N light sources on the marker is solved based on a three-point concentric method₀Obtaining a starting position vector

6. The method for detecting the rotation angle of a crane hook/crane hook as claimed in claim 1, wherein the angle between adjacent light sources in the N light sources on the marker is 30 ° to 100 °, and the light sources are invisible light band lamps, and the front end of the image acquisition device is provided with a filter corresponding to the light source band.

7. A method for eliminating rotation angle error of a crane hook/hanging object is characterized by comprising the following steps:

method for acquiring current spinning angle alpha and co-circular real-time center coordinate D by using crane hook/hanging object rotation angle detection method according to any one of claims 1 to 6_i(x_w,y_w)；

Acquiring the real-time center D of the self-rotating center of the crane hook/hanging object in the common-circle real-time circle center_iCoordinate O in rectangular coordinate system as origin_i＝O₀(x, y); wherein O is₀(x, y) is the initial position of the crane hook/suspended object spin center at the concentric initial circle center D₀Coordinates under a rectangular coordinate system which is an origin;

ideal position of crane hook/hanging object spinning center coordinate O 'after spinning angle is eliminated'_i(x′_B,y′_B) Comprises the following steps:

from D'_iRepresenting the coordinates of the center of the common circle at the ideal position after the spin angle is eliminated, and representing the real-time center D 'of the common circle'_iExists in a rectangular coordinate system with the origin:

under the rectangular coordinate system of the marker image, the initial position vector is obtainedIncluded angle beta between the coordinate axis of the marker image rectangular coordinate system and the horizontal coordinate axis of the marker image rectangular coordinate system, and circle center coordinate D 'of the common circle at the ideal position after the spinning angle is eliminated'_i(x′_w,y′_w) Comprises the following steps:

8. a crane hook/pendant rotation angle detection system, comprising: a marker, an angle detector; the angle detector comprises an image acquisition device and a controller;

the marker is horizontally arranged on the upper surface of the lifting hook, N light sources are arranged on the same circumference of the upper surface of the marker, and N is more than or equal to 3;

the image acquisition device is used for acquiring a real-time marker image and sending the real-time marker image to the controller, the image acquisition device is vertically and downwards installed on the crane trolley, and the marker is positioned in the center of the visual field of the image acquisition device when the lifting hook is static;

the controller comprises an image preprocessing module, a position vector acquisition module and a spinning angle calculation module;

the image preprocessing module is used for preprocessing the real-time marker image, establishing a marker image rectangular coordinate system, acquiring the real-time circle center coordinate of each light source light spot, and simultaneously calculating the average value A of the real-time circle center coordinates of all the light source light spots_i；

The position vector acquisition module is used for solving the co-circle real-time circle center coordinate D of N light sources on the marker based on a three-point co-circle method_iTo obtain a real-time position vectorAnd also for obtaining a preset start position vector

The spin angle calculation module is used for calculating a spin angle based on a real-time position vectorAnd a starting position vectorThe resulting spin angle α is:

9. the crane hook/suspended object rotation angle detection system as claimed in claim 8, wherein the included angle between adjacent light sources in the N light sources on the marker is 30 ° to 100 °, and the light sources are invisible light band lamps, and the front end of the image acquisition device is provided with a filter corresponding to the light source band.

10. A crane hook/pendant rotation angle error cancellation system comprising the crane hook/pendant rotation angle detection system of claim 8 or 9, and the controller further comprising a rotation angle cancellation module;

the rotation angle eliminating module is used for acquiring the current rotation angle alpha and the co-circle real-time circle center coordinate D_i(x_w,y_w)；

Acquiring the real-time center D of the self-rotating center of the crane hook/hanging object in the common-circle real-time circle center_iCoordinate O in rectangular coordinate system as origin_i＝O₀(x, y); wherein O is₀(x, y) is the initial position of the crane hook/suspended object spin center at the concentric initial circle center D₀Coordinates under a rectangular coordinate system which is an origin;

ideal position of crane hook/hanging object spinning center coordinate O 'after spinning angle is eliminated'_i(x′_B,y′_B) Comprises the following steps:

from D'_iRepresenting the coordinates of the center of the common circle at the ideal position after the spin angle is eliminated, and representing the real-time center D 'of the common circle'_iExists in a rectangular coordinate system with the origin:

under the rectangular coordinate system of the marker image, the initial position vector is obtainedIncluded angle beta between the coordinate axis of the marker image rectangular coordinate system and the horizontal coordinate axis of the marker image rectangular coordinate system, and circle center coordinate D 'of the common circle at the ideal position after the spinning angle is eliminated'_i(x′_w,y′_w) Comprises the following steps:

Technical Field

The invention relates to the technical field of crane hook/hanging object state monitoring, in particular to a crane hook/hanging object rotation angle detection method, an error elimination method and a system.

Background

The crane generally comprises a bridge, a cart moving device, a trolley moving device, a lifting device, a control room and the like, wherein the bridge longitudinally moves along rails on two sides, the empty space below the bridge can be fully utilized to hoist goods, and the crane is convenient and labor-saving and widely applied to places such as workshops, harbors and docks, warehouses, high-rise building construction sites and the like.

The existing anti-swing control mainly comprises open-loop control, closed-loop control and a mode of combining open-loop control and closed-loop control. Open loop control is easy to implement, but not precise enough; the closed-loop system has good accuracy, but the position of the trolley and the swing angle of the hoisted object need to be measured at any time as feedback quantity of the controller, wherein the position of the trolley can be obtained through a crane main controller PLC, and the measurement of the swing angle of the hoisted object is the key for realizing closed-loop anti-swing control.

However, the crane can simultaneously have spin motion during swinging, and the spin angle generated by the spin motion can cause a large error on the detection of the swing angle, so how to detect and eliminate the spin angle is the premise of realizing accurate measurement of the swing angle. In the existing studies on detecting the rotation angle, there are some patent documents on the rotation angle: chinese patent CN 110203424B and CN103868447B, etc., these devices can be installed on a crane, but have complex communication transmission with a crane PLC, delay property, and poor applicability.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a method and a system for detecting the rotation angle of a crane hook/a hanging object, and a method and a system for eliminating errors, so that the detection of the rotation angle of the crane hook/the hanging object is realized, the detection is convenient to eliminate, and the accurate measurement of the swing angle is realized.

In a first aspect, a method for detecting a rotation angle of a crane hook/suspended object is provided, which includes:

acquiring a real-time marker image; the marker is horizontally arranged on the upper surface of the lifting hook, N light sources are arranged on the same circumference of the upper surface of the marker, and N is more than or equal to 3; the real-time marker image is acquired by an image acquisition device arranged above the marker;

preprocessing a real-time marker image, establishing a marker image rectangular coordinate system, acquiring the real-time circle center coordinate of each light source light spot, and calculating the average value A of the real-time circle center coordinates of all the light source light spots_i(ii) a And the co-circle real-time circle center coordinate D of N light sources on the marker is solved based on a three-point co-circle method_iTo obtain a real-time position vector

Obtaining a preset initial position vector

Based on real-time position vectorsAnd a starting position vectorThe resulting spin angle α is:

according to the scheme, a plurality of light sources are arranged on a marker, the circle center coordinates of all light source light spots are obtained and averaged, then the circle center of a common circle is obtained according to the principle of three-point common circle, and further a real-time position vector is obtained; and then obtaining a spinning angle based on the real-time position vector and a preset initial position vector. The circle center coordinate is obtained by a method of calculating the circle center through three points in a circle, and compared with a mode of determining the coordinate by a single light source, the method reduces the error and improves the calculation precision of the swing angle.

Further, the preprocessing process comprises:

carrying out noise reduction processing on the real-time marker image;

processing the denoised real-time marker image by adopting an edge detection algorithm to obtain a light source light spot profile corresponding to each light source;

processing the outline of each light source light spot by adopting a connected domain function to obtain the circle center coordinate d of each light source light spot_i(x_i,y_i)(i＝1,2,…,N)。

Further, the noise reduction processing includes: selecting a cross-shaped structural element, performing opening operation of morphological processing on the original image, and removing a fine area with higher brightness in a light source spot of the original image;

when a plurality of circle centers corresponding to the light source light spot profiles are processed by adopting the connected domain function, one circle center is randomly reserved, and other coordinates are removed.

Further, the method based on three-point co-circle is used for solving the co-circle real-time center coordinate D of the N light sources on the marker_iThe method specifically comprises the following steps:

based on the method of three-point co-circle, the centers of the three-point co-circle of the N light sources are co-circleTo obtainCircle center coordinate D'_jThe mean value of the two-dimensional data is used for obtaining a co-circle real-time circle center coordinate D_i：

Obtained by randomly selecting three light sources and utilizing the three-point co-circle principleAnd finally, the final real-time circle center coordinate is obtained by averaging the circle center coordinates, so that the error is reduced, and the detection precision is improved.

Further, the preset starting position vectorObtained by the following method:

acquiring an initial marker image;

preprocessing the initial marker image, establishing a rectangular coordinate system of the marker image, acquiring the initial circle center coordinate of each light source light spot, and simultaneously calculating the average value A of the initial circle center coordinates of all the light source light spots₀(ii) a And the coordinate D of the concentric initial circle center of N light sources on the marker is solved based on a three-point concentric method₀Obtaining a starting position vector

Furthermore, n frames of initial marker images are obtained, and A of the n frames of initial marker images is obtained₀And D₀Obtaining A by averaging₀And D₀Average value of (2)Andfurther obtain the initial position vector

Furthermore, the included angle between adjacent light sources in the N light sources on the marker is 30-100 degrees, the light sources are invisible light band lamps, and the front end of the image acquisition device is provided with a light filter corresponding to the light source band. The included angle between the intersection adjacent light sources is set to be 30-100 degrees, so that the accuracy of solving the center of a common circle based on the three-point common circle principle can be improved. The combination of the invisible light band light source and the optical filter is collected, the influence of the optical fiber in the peripheral environment is eliminated by the negative marker image, and the anti-interference capability is strong.

In a second aspect, a method for eliminating a rotation angle error of a crane hook/a crane object is provided, where the rotation angle error eliminating method is to solve a co-circular center coordinate at an ideal position where a rotation angle is eliminated in a rectangular coordinate system, and includes:

the method for detecting the rotation angle of the crane hook/hanging object is adopted to obtain the current rotation angle alpha and the co-circle real-time circle center coordinate D_i(x_w,y_w)；

Acquiring the real-time center D of the self-rotating center of the crane hook/hanging object in the common-circle real-time circle center_iCoordinate O in rectangular coordinate system as origin_i＝O₀(x, y); wherein O is₀(x, y) is the initial position of the crane hook/suspended object spin center at the concentric initial circle center D₀Coordinates under a rectangular coordinate system which is an origin;

ideal position of crane hook/hanging object spinning center coordinate O 'after spinning angle is eliminated'_i(x’_B,y’_B) Comprises the following steps:

from D'_iThe coordinates of the center of the common circle at the ideal position after the spin angle is eliminated are shown, and the center D of the common circle is the real-time center of the circle_i' exists in a rectangular coordinate system with origin:

under the rectangular coordinate system of the marker image, the initial position vector is obtainedIncluded angle beta between the coordinate axis of the marker image rectangular coordinate system and the horizontal coordinate axis of the marker image rectangular coordinate system, and circle center coordinate D 'of the common circle at the ideal position after the spinning angle is eliminated'_i(x’_w,y’_w) Comprises the following steps:

in a third aspect, there is provided a crane hook/pendant rotation angle detection system comprising: a marker, an angle detector; the angle detector comprises an image acquisition device and a controller;

the marker is horizontally arranged on the upper surface of the lifting hook, N light sources are arranged on the same circumference of the upper surface of the marker, and N is more than or equal to 3;

the image acquisition device is used for acquiring a real-time marker image and sending the real-time marker image to the controller, the image acquisition device is vertically and downwards installed on the crane trolley, and the marker is positioned in the center of the visual field of the image acquisition device when the lifting hook is static;

the controller comprises an image preprocessing module, a position vector acquisition module and a spinning angle calculation module;

the image preprocessing module is used for preprocessing the real-time marker image, establishing a marker image rectangular coordinate system, acquiring the real-time circle center coordinate of each light source light spot, and simultaneously calculating the average value A of the real-time circle center coordinates of all the light source light spots_i；

The position vector acquisition module is used for solving the co-circle real-time circle center coordinate D of N light sources on the marker based on a three-point co-circle method_iTo obtain a real-time position vectorAnd also for obtaining a preset start position vector

The spin angle calculation module is used for calculating a spin angle based on a real-time position vectorAnd a starting position vectorThe resulting spin angle α is:

furthermore, the included angle between adjacent light sources in the N light sources on the marker is 30-100 degrees, the light sources are invisible light band lamps, and the front end of the image acquisition device is provided with a narrow-band filter corresponding to the light source band.

In a fourth aspect, a system for eliminating an error of a crane hook/hanging object rotation angle is provided, which comprises the above system for detecting a crane hook/hanging object rotation angle, and the controller further comprises a rotation angle eliminating module;

the rotation angle eliminating module is used for acquiring the current rotation angle alpha and the co-circle real-time circle center coordinate D_i(x_w,y_w)；

Acquiring the real-time center D of the self-rotating center of the crane hook/hanging object in the common-circle real-time circle center_iCoordinate O in rectangular coordinate system as origin_i＝O₀(x, y); wherein O is₀(x, y) is the initial position of the crane hook/suspended object spin center at the concentric initial circle center D₀Coordinates under a rectangular coordinate system which is an origin;

ideal position of crane hook/hanging object spinning center coordinate O 'after spinning angle is eliminated'_i(x’_B,y’_B) Comprises the following steps:

from D'_iThe coordinates of the center of the common circle at the ideal position after the spin angle is eliminated are shown, and the center D of the common circle is the real-time center of the circle_i' exists in a rectangular coordinate system with origin:

in the marker imageUnder a rectangular coordinate system, calculating a starting position vectorIncluded angle beta between the coordinate axis of the marker image rectangular coordinate system and the horizontal coordinate axis of the marker image rectangular coordinate system, and circle center coordinate D 'of the common circle at the ideal position after the spinning angle is eliminated'_i(x’_w,y’_w) Comprises the following steps:

advantageous effects

The invention provides a method for detecting the rotation angle of a crane hook/hanging object, a method and a system for eliminating errors, which have the following advantages:

(1) the invention can better realize the state monitoring of the crane hook/the hanging object;

(2) compared with the prior art, the swing angle detection method does not detect and eliminate the swing angle, and the swing angle detection precision is obviously improved in the identification and detection of the swing angle of the crane swing;

(3) the invention provides technical support for further realizing the closed-loop anti-swing control technology of the crane and has better application prospect in the intelligent development process of the crane.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a block diagram of a crane hook/pendant rotation angle detection system provided by an embodiment of the present invention;

FIG. 2 is a schematic diagram of a marker structure provided by an embodiment of the present invention;

FIG. 3 is a schematic top plan view of a marker provided in accordance with an embodiment of the present invention;

FIG. 4 is a schematic structural diagram of an angle detector provided in an embodiment of the present invention;

FIG. 5 is a schematic view of the installation position of the marker and the angle detector on the crane according to the embodiment of the present invention;

FIG. 6 is a flow chart of a crane hook/pendant rotation angle detection provided by an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a system for eliminating a rotation angle error of a crane hook/suspended object provided by an embodiment of the invention;

FIG. 8 is a flow chart of a method for eliminating an error in a rotation angle of a crane hook/suspended object according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of a marker image acquired during movement of the crane according to the embodiment of the present invention;

in fig. 10, (a) is a swing angle detection curve without eliminating spin interference; (b) and (3) a swing angle detection curve for eliminating spin interference.

The system comprises a power switch 1, a power indicator lamp 2, a marker shell 3, a light source 4, a first level meter 5, a fixing bolt hole 6, an exhaust fan 7, a collecting device shell 8, an optical filter 9, a lens 10, an industrial camera 11, supporting legs 12, a second level meter 13, a controller 14, a power module 15 and transparent glass 17.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", "center", "longitudinal", "lateral", "vertical", "horizontal", and the like indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, should not be construed as limiting the present invention.

It is noted that the terms "first," "second," and the like in the description of the present invention are used for descriptive purposes only and are not intended to indicate or imply relative importance or order. Further, in the description of the present invention, the meaning of "a plurality" means at least two unless otherwise specified.

Example 1

As shown in fig. 1 to 5, the present embodiment provides a crane hook/suspended object rotation angle detection system, which includes a marker and an angle detector; the angle detector comprises an image acquisition device and a controller;

the marker is horizontally arranged on the upper surface of the lifting hook, N light sources are arranged on the same circumference of the upper surface of the marker, and N is more than or equal to 3;

the image acquisition device is used for acquiring a real-time marker image and sending the real-time marker image to the controller, the image acquisition device is vertically and downwards installed on the crane trolley, and the marker is positioned in the center of the visual field of the image acquisition device when the lifting hook is static;

the controller comprises an image preprocessing module, a position vector acquisition module and a spinning angle calculation module;

the image preprocessing module is used for preprocessing the real-time marker image, establishing a marker image rectangular coordinate system, acquiring the real-time circle center coordinate of each light source light spot, and simultaneously calculating the average value A of the real-time circle center coordinates of all the light source light spots_i；

The position vector acquisition module is used for solving the co-circle real-time circle center coordinate D of N light sources on the marker based on a three-point co-circle method_iTo obtain a real-time position vectorAnd also for obtaining a preset start position vector

The spin angle calculation module is used for calculating a spin angle based on a real-time position vectorAnd a starting position vectorThe resulting spin angle α is:

preferably, the included angle between adjacent light sources in the N light sources on the marker is 30-100 degrees, the light sources are invisible light band lamps, and the front end of the image acquisition device is provided with a narrow band filter corresponding to the light source band.

More specifically, as shown in fig. 2, the marker includes a marker housing, a power supply installed in the marker housing, a power switch 1 installed on the marker housing, a power indicator 2, a light source 4, a first level meter 5, and an exhaust fan 7, wherein the exhaust fan, the light source, and the power indicator are all electrically connected to the power supply, the light source switch is used for controlling the on-off of the power circuit, and the exhaust fan is used for dissipating heat of the marker. In this embodiment, 4 holes are formed in the upper surface of the marker housing 3 on the same circumference with a radius R of 40mm, as shown in fig. 3, and are used for mounting the light source 4, the included angles between the two holes are 45 °, 90 ° and 45 ° from left to right, respectively, the light source preferably selects an infrared lamp with a wavelength of 940nm, 4-section 1.5V batteries are used for supplying power, the marker housing 3 preferably is made of stainless steel or aluminum alloy, and the marker housing 3 is provided with fixing bolt holes 6 for mounting.

The image acquisition device comprises an acquisition device shell 8, an optical filter 9, a lens 10, an industrial camera 11, a second level meter 13 and a power supply module 15, wherein the industrial camera 11, the lens 10 and the optical filter 9 are sequentially arranged from top to bottom, and a controller 14 is integrated in the acquisition device shell 8 and fixed through a supporting leg 12; the industrial camera 11 and the controller 14 are both electrically connected with the power supply module; the bottom of the shell 8 of the collecting device is transparent glass 17. In this embodiment, the filter 9 is a 940nm narrow band filter corresponding to the light source wavelength band.

When the crane hook/hanging object swing angle detection system is used, an initial position vector needs to be set firstlyThe specific process is as follows:

a1: a starting marker image (i.e., a marker image in a resting state) is acquired.

A2: and preprocessing the initial marker image, establishing a rectangular coordinate system of the marker image, and acquiring the initial circle center coordinate of each light source light spot. The method specifically comprises the following steps:

a21: and (3) carrying out noise reduction processing on the initial marker image: selecting a cross-shaped structural element, performing morphological processing opening operation on the initial marker image, and removing a fine region (a region with an area smaller than a preset value) with higher brightness in a light source spot of the initial marker image;

a22: processing the initial marker image after noise reduction by adopting an edge detection algorithm to obtain a light source light spot profile corresponding to each light source;

a23: processing the outline of each light source light spot by adopting a connected domain function to obtain the circle center coordinate d of each light source light spot_i(x_i,y_i)(i＝1,2,…,N)。

A3: calculating the average value A of the initial circle center coordinates of all light source light spots₀：

A4: and the coordinate D of the concentric initial circle center of N light sources on the marker is solved based on a three-point concentric method₀Obtaining a starting position vectorThe method specifically comprises the following steps:

based on the method of three-point co-circle, the centers of the three-point co-circle of the N light sources are co-circleTo obtainCircle center coordinate D'_jThe average value of the two-dimensional data is obtained to obtain the co-circle initial circle center coordinate D₀：

Then based on the co-circle initial circle center coordinate D₀And the mean value A of the initial circle center coordinates₀Obtaining a starting position vector

Then, a real-time marker image (a marker image in the motion process) is obtained, and a real-time position vector is obtained by adopting the same method

And then based on the real-time position vectorAnd a starting position vectorThe resulting spin angle α is:

in particular, to ensure the starting position vectorThe accuracy of (2) can adopt a mode of averaging by multiple measurements, and specifically comprises the following steps: obtaining n frames of initial marker images, and solving A of the n frames of initial marker images by adopting the method₀And D₀Obtaining n A by averaging₀And D₀Average value of (2)Andfurther obtain the initial position vector

Example 2

As shown in fig. 6, the present embodiment provides a method for detecting a rotation angle of a crane hook/suspended object, including:

s1: acquiring a real-time marker image; the marker is horizontally arranged on the upper surface of the lifting hook, N light sources are arranged on the same circumference of the upper surface of the marker, and N is more than or equal to 3; the real-time marker image is acquired by an image acquisition device arranged above the marker;

s2: preprocessing a real-time marker image, establishing a marker image rectangular coordinate system, acquiring the real-time circle center coordinate of each light source light spot, and calculating the average value A of the real-time circle center coordinates of all the light source light spots_i(ii) a And the co-circle real-time circle center coordinate D of N light sources on the marker is solved based on a three-point co-circle method_iTo obtain a real-time position vector

S3: obtaining a preset initial position vector

S4: based on real-time position vectorsAnd a starting position vectorThe resulting spin angle α is:

according to the scheme, a plurality of light sources are arranged on a marker, the circle center coordinates of all light source light spots are obtained and averaged, then the circle center of a common circle is obtained according to the principle of three-point common circle, and further a real-time position vector is obtained; and then obtaining a spinning angle based on the real-time position vector and a preset initial position vector. The circle center coordinate is obtained by a method of calculating the circle center through three points in a circle, and compared with a mode of determining the coordinate by a single light source, the method reduces the error and improves the calculation precision of the swing angle.

Example 3

As shown in fig. 7, this embodiment provides a system for eliminating rotation angle error of crane hook/hanging object, which is different from embodiment 1 only in that the controller further includes a rotation angle eliminating module, and the rotation angle eliminating module is configured to obtain a current rotation angle α and a co-circular real-time center coordinate D_i(x_w,y_w)；

Acquiring the real-time center D of the self-rotating center of the crane hook/hanging object in the common-circle real-time circle center_iCoordinate O in rectangular coordinate system as origin_i＝O₀(x, y); wherein O is₀(x, y) is the initial position of the crane hook/suspended object spin center at the concentric initial circle center D₀Coordinates under a rectangular coordinate system which is an origin;

ideal position of crane hook/hanging object spinning center coordinate O 'after spinning angle is eliminated'_i(x’_B,y’_B) Comprises the following steps:

from D'_iThe coordinates of the center of the common circle at the ideal position after the spin angle is eliminated are shown, and the center D of the common circle is the real-time center of the circle_i' exists in a rectangular coordinate system with origin:

under the rectangular coordinate system of the marker image, the initial position vector is obtainedIncluded angle beta between the coordinate axis of the marker image rectangular coordinate system and the horizontal coordinate axis of the marker image rectangular coordinate system, and circle center coordinate D 'of the common circle at the ideal position after the spinning angle is eliminated'_i(x’_w,y’_w) Comprises the following steps:

fig. 9 is a schematic diagram showing the acquisition of marker images during the movement of the crane. The material for eliminating the spin angle is explained below with reference to fig. 9.

First, at the start position, D₀Is the starting center of a common circle, O₀The starting position is the self-rotating center of the crane hook/hanging object, and the center is defined as D₀The perpendicular bisector of the diameter of the half circle of the marker is the x-axis, and the diameter of the half circle is the y-axis (as the origin point) ((Direction) manually calibrating the coordinate O of the crane hook/suspended object spin center₀(x,y)。

D_iIs a real center of a common circle, O_iFor real-time crane hook/suspended object spin center, with D_iThe perpendicular bisector of the diameter of the half circle of the marker is the x-axis, and the diameter of the half circle is the y-axis (as the origin point) ((In the direction) then the real-time crane hook/suspended object spin center O_iCoordinate of (a) and (O)₀The values of (x, y) being the same, i.e. O_i＝O₀(x,y)。

With real-time crane hook/suspended object spin center O_iD 'obtained by rotating the marker by an angle of alpha as the center'_iTo eliminate after-spin angleA lower common circle center at a desired position; with real-time center D of the circle_iO 'obtained by rotating the marker by an angle of α'_iIn order to eliminate the self-rotating center of the crane hook/suspended object at the ideal position after the self-rotating angle. Thus, it is possible to obtain

Co-circle center coordinate D 'at ideal position after spin angle elimination'_i(x’_w,y’_w) The calculation process is as follows: o is_i＝O₀(x, y) is known, and the rotation angle α is known, whereby O 'can be obtained'_i(x’_B,y’_B)；D_iAre known, andfurther, the co-circle center coordinate D 'at the ideal position where the spin angle is eliminated can be obtained'_i(x’_w,y’_w)。

Example 4

As shown in fig. 8, the present embodiment provides a method for eliminating rotation angle error of a crane hook/suspended object, where the method for eliminating rotation angle error is to solve a co-circular center coordinate of an ideal position under a rectangular coordinate system after a rotation angle is eliminated, and the method includes:

s1: acquiring a real-time marker image; the marker is horizontally arranged on the upper surface of the lifting hook, N light sources are arranged on the same circumference of the upper surface of the marker, and N is more than or equal to 3; the real-time marker image is acquired by an image acquisition device arranged above the marker;

s2: preprocessing the real-time marker image, establishing a marker image coordinate system, acquiring the real-time circle center coordinate of each light source light spot, and calculating the average value A of the real-time circle center coordinates of all the light source light spots_i(ii) a And the co-circle real-time circle center coordinate D of N light sources on the marker is solved based on a three-point co-circle method_i(x_w,y_w) To obtain a real-time position vector

S3: obtaining a preset initial position vector

S4: based on real-time position vectorsAnd a starting position vectorThe resulting spin angle α is:

s5: acquiring the real-time center D of the self-rotating center of the crane hook/hanging object in the common-circle real-time circle center_iCoordinate O in rectangular coordinate system as origin_i＝O₀(x, y); wherein O is₀(x, y) is the initial position of the crane hook/suspended object spin center at the concentric initial circle center D₀Coordinates under a rectangular coordinate system which is an origin;

s6: ideal position of crane hook/hanging object spinning center coordinate O 'after spinning angle is eliminated'_i(x’_B,y’_B) Comprises the following steps:

s7: from D'_iThe coordinates of the center of the common circle at the ideal position after the spin angle is eliminated are shown, and the center D of the common circle is the real-time center of the circle_i' exists in a rectangular coordinate system with origin:

s8: under the rectangular coordinate system of the marker image, the initial position vector is obtainedIncluded angle beta between the coordinate axis of the marker image rectangular coordinate system and the horizontal coordinate axis of the marker image rectangular coordinate system, and circle center coordinate D 'of the common circle at the ideal position after the spinning angle is eliminated'_i(x’_w,y’_w) Comprises the following steps:

to further understand the technical solution of the present invention, the following description is further provided in conjunction with experiments.

A3 m multiplied by 2m crane simulation test bed is set up, a marker is horizontally arranged on the upper surface of a crane hook, a marker power switch is turned on, an angle detector is horizontally arranged on a crane trolley, and the marker is positioned in the center of the visual field of the collected real-time image when the crane hook is static.

The marker is placed at the non-circle center of the rotary platform, and the spinning process of the actual marker is simulated by utilizing the autorotation of the rotary platform. Under the condition that the crane hook/hanging object does not swing and the self-rotation interference is not eliminated, after the crane hook/hanging object rotates 180 degrees, the swing angle detection result is shown in fig. 10 (a); when the rotation angle is rotated by 180 °, the result of detecting the tilt angle is shown in fig. 10 (b).

From theoretical analysis, it can be seen that when the crane hook/pendant is not swinging, the marker rotates 180 ° around the spin center, and the swing angle should be substantially 0 °. As shown in fig. 10(b), during the rotation of the detected swing angle from 0 ° to 180 °, the swing angle is from 0 ° to 0.18 °; after the marker rotates to 180 degrees and is stabilized, the swing angle is also about 0.08 degrees and is very close to 0 degrees. As can be seen from comparison with fig. 10(a), the effect of removing the rotation angle is very good.

Compared with the method without spin elimination and the method with the spin elimination, the method has the advantages that the influence of spin on the swing angle detection is greatly reduced after the spin elimination, and the swing angle detection precision is improved.

It is understood that the same or similar parts in the above embodiments may be mutually referred to, and the same or similar parts in other embodiments may be referred to for the content which is not described in detail in some embodiments.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps of the process, and alternate implementations are included within the scope of the preferred embodiment of the present invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present invention.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.