Apparatus and method for automatically tracking the position of a load on a crane

Abstract

The application discloses a device and method for automatically tracking the position of a crane hoist, wherein the hoist device moves in the vertical direction through the lifting device; the camera holder is fixedly arranged below the trolley mechanism; the camera device is fixed on the camera holder; the camera assembly is in communication connection with the computing unit; the first signal acquisition device and the second signal acquisition device are both in communication connection with the computing unit; the first signal acquisition device is arranged on the trolley mechanism; and the second signal acquisition device is arranged on the lifting mechanism. According to the position coordinates of the crane trolley mechanism and the lifting mechanism, the rotating angle of the camera device and the focal length of the camera device are obtained, and the camera device automatically tracks the hoist device. The crane operator can realize real-time and intuitive understanding of the running condition of the hoist device through the camera device, avoids too much attention dispersion, guarantees the safety of the crane hoisting process, and effectively improves the hoisting efficiency.

Description

Technical Field

[0001] This invention relates to the field of crane video monitoring technology, and in particular to a device and method for automatically tracking the position of a crane load. Background Technology

[0002] Cranes are indispensable large-scale equipment in the industrial field, commonly used in construction, metallurgy, ports, and other lifting scenarios. Their lifting capacity is measured in tons. The operator's cab of existing cranes is generally located at a high position; for example, it is located below the main beam of a bridge crane, and above the slewing mechanism of a gantry crane. Operators in the cab have excellent visibility and can assess the lifting environment. However, sometimes due to obstructions or angle issues, the operator cannot see the hook and the entire load, and must operate the crane by communicating with the supervisor. Furthermore, operators need to maintain a high level of concentration during operation, which can easily lead to fatigue and pose certain safety hazards.

[0003] Existing video surveillance systems for cranes utilize cameras installed at key locations on the crane and displays in the operator's cab, allowing operators to monitor the crane's overall operation. However, these systems are typically fixed in place, meaning their viewing angle and focus are predetermined and cannot be automatically adjusted, requiring manual intervention. This forces operators to multitask, monitoring multiple video feeds simultaneously. Crane operation is already a demanding and highly focused job; this additional method significantly increases the pressure on operators. Summary of the Invention

[0004] The present invention provides an apparatus and method for automatically tracking the position of a crane load, in order to overcome the above-mentioned technical problems.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] An automatic tracking device for the lifting position of a crane includes a trolley mechanism, a trolley mechanism, and a computing unit; the trolley mechanism is provided with a trolley mechanism running track, and the trolley mechanism is mounted on the trolley mechanism and moves along the trolley mechanism running track; it also includes: a hoisting mechanism, a camera assembly, a first signal acquisition device, and a second signal acquisition device;

[0007] The lifting mechanism includes a lifting device and a hoisting device; the lifting device is fixedly mounted on the trolley mechanism; the hoisting device is connected to the lifting device and moves vertically in the vertical direction through the lifting device.

[0008] The camera assembly includes a camera pan-tilt unit and a camera device; the camera pan-tilt unit is fixedly installed below the trolley mechanism; the camera device is fixedly connected to the camera pan-tilt unit;

[0009] The first signal acquisition device is installed on the trolley mechanism to obtain the coordinates of position point A of the trolley mechanism in real time;

[0010] The second signal acquisition device is installed on the hoisting device to obtain the coordinates of the position point C of the hoisting device in real time;

[0011] Both the first signal acquisition device and the second signal acquisition device are communicatively connected to the computing unit to obtain the rotation angle and focal length of the camera device based on the coordinates of the position point A of the trolley mechanism, the coordinates of the position point C of the hoisting device, and the coordinates of the position point B of the camera device.

[0012] The computing unit is communicatively connected to the camera pan-tilt unit to transmit the rotation angle and focal length of the camera device to the camera pan-tilt unit, and controls the movement of the camera device through the camera pan-tilt unit to achieve automatic tracking of the hoisting device;

[0013] The first signal acquisition device, the second signal acquisition device, the computing unit, and the camera assembly are all connected to a power source.

[0014] Furthermore, the trolley mechanism includes two main beams, a first end beam, and a second end beam; the first end beam and the second end beam are arranged in parallel relative to each other.

[0015] Both ends of the main beam are fixedly connected to one end of the first end beam and one end of the second end beam, respectively; and the two main beams are arranged relatively parallel to each other.

[0016] The trolley mechanism's running track is arranged parallel to the main beam, so that the trolley mechanism can move along the trolley mechanism's running track.

[0017] A method for automatically tracking the position of a crane load includes the following steps:

[0018] S1: Establish a rectangular coordinate system with the midpoint of the first end beam as the origin of the coordinate system; the direction of the large trolley mechanism forward is the positive x-axis, the direction of the small trolley mechanism forward is the positive y-axis, and the vertical upward direction is the positive z-axis.

[0019] S2: Obtain the coordinates of position point A of the trolley mechanism through the first signal acquisition device; obtain the coordinates of position point C of the hoisting device through the second signal acquisition device;

[0020] S3: Based on the coordinates of position point A of the trolley mechanism and the coordinates of position point B of the camera device, obtain the rotation angle α of the camera device around the z-axis.final ;

[0021] S4: Based on the coordinates of the position point C of the hoisting device and the coordinates of the position point B of the camera device, obtain the rotation angle β of the camera device around the x-axis and the focal length D of the camera device;

[0022] S5: Based on the rotation angle α of the camera device around the z-axis final The camera's rotation angle β around the x-axis and its focal length D are used to control the camera angle and track the hoisting device in real time.

[0023] Furthermore, the rotation angle α of the camera device about the z-axis final The calculation is as follows:

[0024] The angle α between line AB and the negative x-axis is obtained as follows:

[0025] tanα=(y1-y c ) / x c (100)

[0026] In the formula: y1 is the coordinate of the trolley mechanism on the y-axis; y c x is the coordinate of the camera device on the y-axis; c The coordinates of the camera device on the x-axis;

[0027]

[0028] In the formula: αinit is the initial camera angle of the camera device.

[0029] Furthermore, the angle β between the line BC and the plane z = 0 is calculated as follows:

[0030]

[0031] In the formula: z c x is the coordinate of the camera device on the z-axis; z3 is the coordinate of the hoisting device on the z-axis; x c y3 is the coordinate of the camera device on the x-axis; y4 is the coordinate of the hoisting device on the y-axis; y5 is the coordinate of the hoisting device on the y-axis; c Let be the coordinates of the camera device on the y-axis.

[0032] Furthermore, the focal length of the camera device is calculated as follows:

[0033] The distance between point C and point B is calculated as follows:

[0034]

[0035] In the formula: l BC x is the distance between point C and point B; cy3 is the coordinate of the camera device on the x-axis; y4 is the coordinate of the hoisting device on the y-axis; y5 is the coordinate of the hoisting device on the y-axis; c The coordinates of the camera device on the y-axis; z c z1 is the coordinate of the camera device on the z-axis; z2 is the coordinate of the hoisting device on the z-axis;

[0036] The focal length of the camera device is calculated as follows:

[0037] D = l BC ×D max / l max (400)

[0038] In the formula: D is the focal length of the camera device; D max The focal length when the hoisting device and the camera device are at their furthest distance; max This represents the furthest distance between the hoisting device and the camera device.

[0039] Beneficial Effects: The present invention provides an automatic tracking device and method for the lifting position of a crane. Based on the position coordinates of the crane trolley mechanism and the hoisting mechanism, a calculation unit obtains the rotation angle and focal length of the camera device, enabling the camera device to automatically track the lifting device. Crane operators can obtain real-time and intuitive information about the operation of the lifting device through the camera device, avoiding excessive distraction, ensuring safety during the crane lifting process, and effectively improving lifting efficiency. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the device for automatically tracking the lifting position of a crane according to the present invention;

[0042] Figure 2 This is a top view of the device for automatically tracking the lifting position of a crane according to the present invention;

[0043] Figure 3 This is a flowchart of the method for automatically tracking the position of a crane load using a camera according to the present invention;

[0044] Figure 4 This is a schematic diagram of a rectangular coordinate system in an embodiment of the present invention.

[0045] The components are: 1. Trolley mechanism; 11. Main beam; 12. First end beam; 13. Second end beam; 2. Trolley mechanism; 21. Trolley mechanism running track; 3. Lifting mechanism; 31. Lifting device; 4. Camera pan-tilt head; 5. Camera device; 6. Lifting device. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0047] This embodiment provides a device for automatically tracking the position of a crane's load, such as... Figure 1-2 As shown, it includes a trolley mechanism 1, a trolley mechanism 2, a lifting mechanism 3, and a calculation unit; the trolley mechanism is provided with a trolley mechanism running track 21, and the trolley mechanism 2 is provided on the trolley mechanism 1 and moves along the trolley mechanism running track 21;

[0048] It also includes: lifting mechanism 3, camera assembly, first signal acquisition device, and second signal acquisition device;

[0049] The lifting mechanism 3 includes a lifting device 31 and a hoisting device 6; the hoisting device 6 is connected to the lifting device 31 and moves vertically in the vertical direction through the lifting device 31; the lifting device 31 is fixedly mounted on the trolley mechanism 2.

[0050] The trolley mechanism 1 includes two main beams 11, a first end beam 12, and a second end beam 13; the first end beam 12 and the second end beam 13 are arranged in parallel relative to each other.

[0051] Both ends of the main beam 11 are fixedly connected to one end of the first end beam 12 and the second end beam 13, respectively; and the two main beams 11 are arranged relatively parallel to each other.

[0052] A trolley mechanism running track 21 is provided on the main beam 11 along a direction parallel to the main beam 11, and the trolley mechanism 2 moves along the trolley mechanism running track 21;

[0053] Specifically, in this embodiment, the lifting mechanism is a commonly used lifting mechanism in the field that enables the lifting device to move in the vertical direction. The lifting device 6 is a common object-grabbing device in the field, such as a hook, grab bucket, or electric disk, which will not be described in detail here.

[0054] The camera assembly includes a camera pan-tilt head 4 and a camera device 5; the camera pan-tilt head 4 is fixedly installed below the main beam 11; the camera device 5 is fixed on the camera pan-tilt head 4;

[0055] Specifically, in this embodiment, the camera pan-tilt head 4 is a common electric pan-tilt head that can control the rotation of the camera, and the camera device 5 is an ordinary camera.

[0056] The first signal acquisition device is installed on the trolley mechanism to obtain the coordinates of position point A of the trolley mechanism in real time;

[0057] The second signal acquisition device is installed on the hoisting device to obtain the coordinates of the position point C of the hoisting device 6 in real time;

[0058] Both the first signal acquisition device and the second signal acquisition device are communicatively connected to the computing unit to obtain the rotation angle and focal length of the camera device based on the coordinates of the position point A of the trolley mechanism, the coordinates of the position point C of the hoisting device, and the coordinates of the position point B of the camera device.

[0059] The computing unit is communicatively connected to the camera pan-tilt unit 4 to transmit the rotation angle and focal length of the camera device to the camera pan-tilt unit, and controls the movement of the camera device 5 through the camera pan-tilt unit to achieve automatic tracking of the hoisting device;

[0060] Specifically, in this embodiment, both the first signal acquisition device and the second signal acquisition device are commonly used position sensors; they will not be described in detail here.

[0061] The first signal acquisition device, the second signal acquisition device, the computing unit, and the camera assembly are all connected to a power source.

[0062] Specifically, in this embodiment, both the first signal acquisition device and the second signal acquisition device are common position sensors available on the market.

[0063] Working principle: In this embodiment, the real-time positions of the trolley mechanism and the hoisting device are collected by the first signal acquisition device and the second signal acquisition device, respectively. The real-time positions of the trolley mechanism and the hoisting device are transmitted to the computing unit through the communication line. The computing unit calculates the rotation parameters of the camera device based on the real-time positions of the trolley mechanism and the hoisting device, and outputs the rotation parameters of the camera device to the camera assembly through the communication line, thereby controlling the rotation angle of the camera device and realizing real-time tracking of the hoisting device.

[0064] The calculation unit uses the calculation method in the automatic tracking crane lifting position method of the camera in this embodiment to obtain the rotation angle and focal length of the camera device software program computer chip, and can output the obtained rotation angle and focal length of the camera device, so that the camera pan-tilt head can control the rotation of the camera device according to the rotation angle and focal length of the camera device.

[0065] The steps of the method for automatically tracking the crane's hoisting position using a camera in this embodiment are as follows: (see attached) Figure 3 As shown:

[0066] S1: A rectangular coordinate system is established with the midpoint of the first end beam as the origin; the direction of the trolley mechanism's movement is the positive x-axis, the direction of the trolley mechanism's movement is the positive y-axis, and the vertically upward direction is the positive z-axis; as shown in the attached figure. Figure 4 As shown.

[0067] S2: Obtain the coordinates of position point A of the trolley mechanism through the first signal acquisition device; obtain the coordinates of position point C of the hoisting device through the second signal acquisition device; since the camera assembly and the trolley mechanism always remain relatively stationary, the running position information of the trolley mechanism is not calculated.

[0068] S3: Based on the coordinates of position point A of the trolley mechanism and the coordinates of position point B of the camera device, obtain the rotation angle α of the camera device around the z-axis. final ;

[0069] The camera device rotates about the z-axis by an angle α. final The calculation is as follows:

[0070] The angle α between line AB and the negative x-axis is obtained as follows, where line AB is the line connecting position point A of the trolley mechanism and position point B of the camera device:

[0071] tanα=(y1-y c ) / x c (100)

[0072] In the formula: y1 is the coordinate of the trolley mechanism on the y-axis; y c x is the coordinate of the camera device on the y-axis; c The coordinates of the camera device on the x-axis;

[0073] Among them, the position of the camera device B(x) c y c , z c The position of the trolley mechanism A(0, y1, 0) is fixed, while the position of the trolley mechanism A(0, y1, 0) is constantly changing. The value of angle α can be calculated in real time based on the changing value of y1.

[0074] Since each camera device is manufactured and installed, it has an initial angle α relative to the x-axis. init Therefore, the actual rotation angle of the camera device around the z-axis is calculated as follows:

[0075]

[0076] In the formula: α init This is the initial camera angle of the camera device.

[0077] Due to α final The value of α must be in the interval [0, 360), therefore when α final When the value is greater than or equal to 360, 360 must be subtracted before the final value can be used as a parameter to directly control the camera device.

[0078] In this embodiment, all distances are measured in meters.

[0079] S4: Based on the coordinates of the position point C of the hoisting device and the coordinates of the position point B of the camera device, the rotation angle β of the camera device around the x-axis (the angle between the straight line BC and the plane z = 0) and the focal length D of the camera device are obtained by the calculation unit in this embodiment.

[0080] The angle β between the line BC and the plane z = 0 is calculated as follows, where the line BC is the line connecting the position point C of the hoisting device and the position point B of the camera device:

[0081]

[0082] In the formula: z c x is the coordinate of the camera device on the z-axis; z3 is the coordinate of the hoisting device on the z-axis; x c y3 is the coordinate of the camera device on the x-axis; y4 is the coordinate of the hoisting device on the y-axis; y5 is the coordinate of the hoisting device on the y-axis; c Let be the coordinates of the camera device on the y-axis.

[0083] Specifically, the camera component B(x) c y c , z c The position of the hoisting device A(0, y3, z3) is fixed, while the position of the hoisting device A(0, y3, z3) is variable. The value of angle β, i.e., the vertical rotation parameter, can be calculated in real time based on the changing values ​​of y3 and z3.

[0084] The focal length of the camera device is calculated as follows:

[0085] The distance between point C and point B is calculated as follows:

[0086]

[0087] In the formula: l BCx is the distance between point C and point B; c 3 represents the coordinates of the camera device on the x-axis; 3 represents the coordinates of the hoisting device on the y-axis; y c The coordinates of the camera device on the y-axis; z c z1 is the coordinate of the camera device on the z-axis; z2 is the coordinate of the hoisting device on the z-axis.

[0088] The focal length of the camera device is calculated as follows:

[0089] D = l BC ×D max / l max (400)

[0090] In the formula: D is the focal length of the camera device; D max The focal length when the hoisting device and the camera device are at their furthest distance; max This represents the furthest distance between the hoisting device and the camera device.

[0091] S5: Based on the rotation angle α of the camera device around the z-axis final The camera's rotation angle β around the x-axis and its focal length D are used to control the camera angle and track the hoisting device in real time.

[0092] Specifically, in this embodiment, the computing unit calculates the rotation angle α of the camera device around the z-axis. final The camera device's rotation angle β around the x-axis and its focal length D are transmitted to the camera assembly. The camera pan-tilt unit adjusts its angle according to these parameters to achieve the rotation of the camera device.

[0093] The device and method for automatically tracking the position of a crane load using a camera, as described in this invention, have the following beneficial effects:

[0094] 1. Real-time tracking of the lifting device was achieved by combining the unique structure of the crane. In a crane, the lifting device moves within a limited range. Utilizing this characteristic, parameters are calculated based on the positions of the crane trolley mechanism and the hoisting mechanism, and the camera is controlled to achieve real-time tracking of the lifting device.

[0095] 2. The device of this invention has a simple structure and can be applied to various specifications and models of cranes on the market. The data required for calculating the camera control parameters of this invention are only the positions of the trolley mechanism and the hoisting mechanism, and are independent of the external structure, environment, and data of the crane. Therefore, it can be used in most cranes.

[0096] 3. Highly scalable and flexible. This invention can be expanded to include camera components to meet different needs. For example, it can be expanded into a crane or a device with two camera components, enabling real-time tracking of the hoisting device from two different angles.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A device for automatically tracking the lifting position of a crane, comprising a trolley mechanism (1), a trolley mechanism (2), wherein the trolley mechanism is provided with a trolley mechanism running track (21), and the trolley mechanism (2) is disposed on the trolley mechanism (1) and moves along the trolley mechanism running track (21); characterized in that: include: Lifting mechanism (3), several camera components, first signal acquisition device, second signal acquisition device; Computational unit; The lifting mechanism (3) includes a lifting device (31) and a hoisting device (6); the lifting device (31) is fixedly mounted on the trolley mechanism (2); the hoisting device (6) is connected to the lifting device (31) and moves vertically in the vertical direction through the lifting device (31); The camera assembly includes a camera pan-tilt unit (4) and a camera device (5); the camera pan-tilt unit (4) is fixedly installed below the trolley mechanism (1); the camera device (5) is fixedly connected to the camera pan-tilt unit (4); The first signal acquisition device is installed on the trolley mechanism to obtain the coordinates of position point A of the trolley mechanism in real time; The second signal acquisition device is installed on the hoisting device to obtain the coordinates of the position point C of the hoisting device (6) in real time; Both the first signal acquisition device and the second signal acquisition device are communicatively connected to the computing unit to obtain the rotation angle and focal length of the camera device based on the coordinates of the position point A of the trolley mechanism, the coordinates of the position point C of the hoisting device, and the coordinates of the position point B of the camera device. The rotation angle α of the camera device around the z-axis fianl The calculation is as follows: The angle α between line AB and the negative x-axis is obtained as follows: tanα=(y1-y c ) / x c (100) In the formula: y1 is the coordinate of the trolley mechanism on the y-axis; y c x is the coordinate of the camera device on the y-axis; c The coordinates of the camera device on the x-axis; In the formula: α init This is the initial camera angle of the camera device; The rotation angle β of the camera device around the x-axis is calculated as follows: In the formula: z c x is the coordinate of the camera device on the z-axis; z3 is the coordinate of the hoisting device on the z-axis; x c y3 is the coordinate of the camera device on the x-axis; y4 is the coordinate of the hoisting device on the y-axis; y5 is the coordinate of the hoisting device on the y-axis; c The coordinates of the camera device on the y-axis; The focal length of the camera device is calculated as follows: The distance between point C and point B is calculated as follows: In the formula: l BC x is the distance between point C and point B; c y3 is the coordinate of the camera device on the x-axis; y4 is the coordinate of the hoisting device on the y-axis; y5 is the coordinate of the hoisting device on the y-axis; c The coordinates of the camera device on the y-axis; z c z1 is the coordinate of the camera device on the z-axis; z2 is the coordinate of the hoisting device on the z-axis; The focal length of the camera device is calculated as follows: D=l BC ×D max / L max (400) In the formula: D is the focal length of the camera device; D max The focal length when the hoisting device and the camera device are at their furthest distance; max This represents the furthest distance between the hoisting device and the camera device. The computing unit is communicatively connected to the camera pan-tilt unit (4) to transmit the rotation angle and focal length of the camera device to the camera pan-tilt unit, and controls the movement of the camera device (5) through the camera pan-tilt unit to achieve automatic tracking of the hoisting device; The first signal acquisition device, the second signal acquisition device, the computing unit, and the camera assembly are all connected to a power source.

2. The device for automatically tracking the lifting position of a crane according to claim 1, characterized in that, The trolley mechanism (1) includes two main beams (11), a first end beam (12), and a second end beam (13); the first end beam (12) and the second end beam (13) are arranged relatively parallel to each other. The two ends of the main beam (11) are fixedly connected to one end of the first end beam (12) and the second end beam (13), respectively; and the two main beams (11) are arranged in parallel relative to each other; The trolley mechanism running track (21) is arranged parallel to the main beam (11) so that the trolley mechanism (2) moves along the trolley mechanism running track (21).

3. The method for automatically tracking the lifting position of a crane according to any one of claims 1 to 2, characterized in that, Includes the following steps: S1: A rectangular coordinate system is established with the midpoint of the first end beam (12) as the origin of the coordinate system; the direction of the large trolley mechanism (1) is the positive x-axis, the direction of the small trolley mechanism (2) is the positive y-axis, and the vertical upward direction is the positive z-axis. S2: Obtain the coordinates of position point A of the trolley mechanism (2) through the first signal acquisition device; obtain the coordinates of position point C of the hoisting device (6) through the second signal acquisition device; S3: Based on the coordinates of position point A of the trolley mechanism (2) and the coordinates of position point B of the camera device, obtain the rotation angle α of the camera device around the z-axis. fianl ; S4: Based on the coordinates of the position point C of the hoisting device (6) and the coordinates of the position point B of the camera device, obtain the rotation angle β of the camera device around the x-axis and the focal length D of the camera device; S5: Based on the rotation angle α of the camera device around the z-axis fianl The camera's rotation angle β around the x-axis and its focal length D are used to control the camera angle and track the hoisting device in real time.

4. The method for automatically tracking the lifting position of a crane according to claim 3, characterized in that, The camera device rotates about the z-axis by an angle α. fianl The calculation is as follows: The angle α between line AB and the negative x-axis is obtained as follows: tanα=(y1-y c ) / x c (100) In the formula: y1 is the coordinate of the trolley mechanism on the y-axis; y c x is the coordinate of the camera device on the y-axis; c The coordinates of the camera device on the x-axis; In the formula: α init This is the initial camera angle of the camera device.

5. The method for automatically tracking the lifting position of a crane according to claim 4, characterized in that, The angle β between the line BC and the plane z = 0 is calculated as follows: In the formula: z c x is the coordinate of the camera device on the z-axis; z3 is the coordinate of the hoisting device on the z-axis; x c y3 is the coordinate of the camera device on the x-axis; y4 is the coordinate of the hoisting device on the y-axis; y5 is the coordinate of the hoisting device on the y-axis; c Let be the coordinates of the camera device on the y-axis.

6. The method for automatically tracking the lifting position of a crane according to claim 5, characterized in that, The focal length of the camera device is calculated as follows: The distance between point C and point B is calculated as follows: In the formula: l BC x is the distance between point C and point B; c y3 is the coordinate of the camera device on the x-axis; y4 is the coordinate of the hoisting device on the y-axis; y5 is the coordinate of the hoisting device on the y-axis; c The coordinates of the camera device on the y-axis; z c z1 is the coordinate of the camera device on the z-axis; z2 is the coordinate of the hoisting device on the z-axis; The focal length of the camera device is calculated as follows: D=l BC ×D max / L max (400) In the formula: D is the focal length of the camera device; D max The focal length when the hoisting device and the camera device are at their furthest distance; max This represents the furthest distance between the hoisting device and the camera device.

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