Crane and swing eliminating method thereof
By installing gyroscopes and ranging components on the crane, the movement status of the lifting objects is monitored and measured in real time, and the movement status of the vehicle body is adjusted through the control system, the swing problem during crane lifting is solved, achieving a more efficient and safe lifting Transport operation.
Patent Information
- Application Number
- CN202411795441.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-02-21
AI Technical Summary
Existing cranes have swing problems when lifting heavy objects, and lack effective active anti-swing mechanisms, resulting in low lifting accuracy and efficiency, and safety hazards.
By installing a gyroscope on the crane hook and installing distance measuring components on the vehicle body, the swing attitude and linear displacement changes of the object are monitored and measured in real time, the data is transmitted to the control system, and the movement status of the vehicle body is adjusted after comprehensive analysis. , eliminate the swing of the hanging object.
Effectively eliminate the swing of the hanging objects, improve the lifting accuracy and efficiency, ensure the safety of the operator and the surrounding environment, and the cost and maintenance difficulty are low.
Smart Images
Figure CN119490131A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of cranes, and in particular to a crane and a method for eliminating swing thereof. Background Art
[0002] In the development history of lifting equipment, the swing problem of cranes when lifting heavy objects has always been a key problem in the industry; eliminating swing is one of the necessary skills for crane operators and is an indispensable work link in completing each lifting work cycle; the so-called eliminating swing means that the crane operator stabilizes the hook or the object being lifted that is swinging due to various reasons during the process of lifting goods. However, the existing crane technology has many shortcomings in dealing with the swing of heavy objects.
[0003] First, most traditional cranes lack an effective active anti-sway mechanism. During the process of lifting and moving heavy objects, the heavy objects are prone to swing due to various factors (such as changes in lifting speed, acceleration or deceleration of the trolley, interference from the external environment, etc.). This swing not only affects the accuracy and efficiency of the lifting, but may also pose a safety hazard to surrounding personnel and equipment.
[0004] Secondly, some existing anti-sway technologies are often too complicated, requiring a large number of sensors and complex control systems, which increases the cost and maintenance difficulty of the equipment. Moreover, the effect of these technologies in practical applications is not ideal and cannot completely eliminate the swing of heavy objects. Summary of the invention
[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a crane which can provide real-time feedback on the movement posture of the hoisted object by adding a distance measuring component and a gyroscope. When the control system determines restarting and stopping, the maximum swing distance can be reduced to ensure the safety of the operator and the surrounding environment.
[0006] In order to achieve the above object, the technical solution adopted by the present invention is: A crane comprises a car body mounted on a bridge frame, an electric hoist mounted on the car body, a hook for lifting a load connected to the lower part of the electric hoist via a rope, a control system is arranged on one side of the car body, and further comprises a distance measuring component for measuring the linear displacement change of the load and a gyroscope for monitoring the swing posture change of the load, the distance measuring component being mounted on the car body, and the gyroscope being mounted on the hook.
[0007] Optionally, the distance measuring component is used to measure the displacement change of the hanging object relative to the vehicle body, and the distance measuring component adopts a laser rangefinder.
[0008] A method for eliminating swing of a crane, which obtains linear displacement data of a suspended object through a distance measuring component and angular motion data of the suspended object in space through a gyroscope; transmits the collected data to a control system, which comprehensively analyzes the two types of data to determine the real-time motion state of the suspended object; and then adjusts the motion state of the vehicle body according to the motion state of the suspended object to ensure that the suspended object is in a stable lifting state.
[0009] Optionally, the linear displacement data includes the change in distance of the suspended object relative to the vehicle body in the horizontal and vertical directions, and the angular motion data includes the angular velocity and angular acceleration of the suspended object swinging in space.
[0010] Optionally, after receiving the linear displacement data and angular motion data of the hanging object, the control system preprocesses the data first; the preprocessing includes calibrating the timestamp to ensure the accuracy and synchronization of the data.
[0011] Optionally, if the suspended object lags behind the vehicle body when starting, the vehicle body is braked, and when the suspended object swings forward and crosses the vertical line of the relative equilibrium position between it and the vehicle body, the vehicle body is started forward to follow the vehicle until the suspended object and the vehicle body run at the same speed.
[0012] Optionally, the vehicle body is braked before the predetermined parking position, and when the suspended object swings in the forward direction, the vehicle is immediately braked to follow until the suspended object stops steadily at the predetermined parking position.
[0013] Optionally, if the suspended object swings back and forth relative to the vehicle body after parking, the vehicle body first follows the vehicle in the direction of the swing of the suspended object until it stops after half of the maximum swing amplitude of the suspended object. When the suspended object swings back, the vehicle body is started to follow the vehicle back until the vehicle body and the suspended object are on a vertical line in a relative equilibrium position.
[0014] Optionally, if the suspended object swings forward relative to the vehicle body during operation, the speed of the vehicle body is increased along the swing direction of the suspended object so that the vehicle body keeps up with the swing of the suspended object; when the suspended object swings back, the speed of the vehicle body is reduced so that the suspended object keeps up with the operating angle of the vehicle body to reduce the swing amplitude of the suspended object until the vehicle body and the suspended object run smoothly at the same time.
[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) In the present invention, by installing a gyroscope on the hook, the swing posture change of the hanging object can be monitored in real time, and by installing a distance measuring component on the vehicle body, the linear displacement change of the hanging object can be measured in real time. After the data obtained by the two are transmitted to the control system, the control system determines the real-time motion state of the hanging object, and then adjusts the motion state of the vehicle body accordingly to eliminate the swing of the hanging object and ensure the safety of the operator and the surrounding environment. The device can eliminate the swing, and the cost and maintenance difficulty are lower than the existing technology; (2) In the present invention, the distance change of the suspended object relative to the vehicle body in the horizontal and vertical directions can be obtained through the distance measuring component, and the angular velocity and angular acceleration of the suspended object swinging in space can be obtained through the gyroscope. Then, the real-time motion state of the suspended object can be determined by the control system, which provides reliable data support for eliminating the swing of the suspended object and greatly reduces the difficulty of eliminating the swing for the operator. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 is a structural schematic diagram of a crane according to an embodiment of the present invention; Figure 2 is a schematic side structural diagram of a crane according to an embodiment of the present invention; Figure 3 It is a schematic diagram of a structure for eliminating swinging when starting a vehicle in an embodiment of the present invention; Figure 4 2 is a schematic diagram of a structure for eliminating swing after parking in an embodiment of the present invention; Figure 5 2 is a schematic diagram of a structure for eliminating swinging before parking in an embodiment of the present invention; Among them, 1. Car body; 2. Electric hoist; 3. Hook; 4. Control system; 5. Distance measurement component; 6. Hoisted objects. DETAILED DESCRIPTION
[0017] The present invention will now be further described in detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams that only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.
[0018] Embodiment 1
[0019] like Figure 1-Figure 2As shown, a crane comprises a car body 1, an electric hoist 2, a hook 3, a control system 4, a distance measuring component 5 and a gyroscope. The car body 1 is installed on a bridge and can move along it, and the electric hoist 2 is installed on the car body 1 and can move synchronously with it; the hook 3 is connected to the bottom of the electric hoist 2 through a rope, and the hook 3 is used to lift a hanging object 6, and the hook 3 moves synchronously with the hanging object 6 in space, and the electric hoist 2 can drive the rope to wind to control the height of the hook 3 and the hanging object 6; the distance measuring component 5 is installed on the car body 1, the gyroscope is installed on the hook 3, and the control system 4 is installed on one side of the car body 1; the distance measuring component 5 is used to measure the linear displacement change of the hanging object 6 in real time, and the gyroscope is used to monitor the swing posture change of the hanging object 6 in real time, and the data obtained by the distance measuring component 5 and the gyroscope will be transmitted to the control system 4 for processing.
[0020] Among them, the distance measuring component 5 is used to measure the displacement change of the suspended object 6 relative to the vehicle body 1, and the distance measuring component 5 adopts a laser rangefinder; in addition, the laser rangefinder can be installed in multiple positions of the crane, such as on the bridge, as long as the laser beam can be accurately irradiated on the suspended object 6, and the measurement angle and range can be adjusted according to actual needs.
[0021] There are different solutions to eliminate the swing of the suspended object 6 depending on the actual situation. However, the overhead crane operator in the workshop cannot pay full attention 24 hours a day. Therefore, a laser rangefinder is added to the body 1 near the main engine, and a gyroscope is added to the hook 3. The two sensors cooperate with each other. When the crane starts the lifting operation and the electric hoist 2 starts to lift the suspended object 6, the laser rangefinder and the gyroscope on the hook 3 start working at the same time.
[0022] After the data obtained by the ranging component 5 and the gyroscope are transmitted to the control system 4, the control system 4 determines the real-time movement state of the suspended object 6, and then adjusts the movement state of the vehicle body 1 accordingly to eliminate the swing of the suspended object 6 and ensure the safety of the operator and the surrounding environment; the device can eliminate the swing, and the cost and maintenance difficulty are lower than the existing technology.
[0023] In addition, by installing a force sensor on the electric hoist 2, the real-time force on the rope (steel cable or chain) can be detected during the operation of the vehicle body 1. When the hanging object 6 reaches the designated location, the vehicle body 1 determines the posture of the hanging object 6 according to the actual force, and then adopts a corresponding method to eliminate the swing; the following or returning distance of the vehicle body 1 is determined according to the force of the force sensor on the rope, ensuring that the hanging object 6 can reach the designated location without swinging. Among them, following the vehicle means that the vehicle body 1 accelerates to catch up in the direction where the hanging object 6 is.
[0024] Embodiment 2
[0025] On the basis of the first embodiment, the present invention further proposes a method for eliminating the swing of a crane, wherein the linear displacement data of the suspended object 6 is obtained through the distance measuring component 5, and the angular motion data of the suspended object 6 in space is obtained through the gyroscope; and the collected data is transmitted to the control system 4, and the control system 4 comprehensively analyzes the two types of data to determine the real-time motion state of the suspended object 6; and then the motion state of the vehicle body 1 is adjusted accordingly according to the motion state of the suspended object 6 to ensure that the suspended object 6 is in a stable lifting state.
[0026] When the hanging object 6 approaches the maximum swing amplitude (when the hanging object 6 swings to this amplitude, it will swing back), stop following the vehicle, so that the hanging object 6 is in a vertical position; the following speed and following distance are determined according to the swing position of the hanging object 6 when starting the following vehicle and the size of the swing amplitude of the hanging object 6. Similarly, if the swing is not completely eliminated by following the vehicle once, you can follow the vehicle back once. If the following speed and following distance are selected appropriately, the hanging object 6 can be stabilized by following the vehicle 1 to 2 times.
[0027] As mentioned above, the linear displacement data includes the distance change of the hanging object 6 relative to the vehicle body 1 in the horizontal and vertical directions, and the angular motion data includes the angular velocity and angular acceleration of the hanging object 6 in the space; the laser rangefinder continuously monitors the distance change of the hanging object 6 relative to the vehicle body 1 (or other fixed points) in the horizontal and vertical directions, obtains the linear displacement data of the hanging object 6, and thus determines its position change; the gyroscope measures the angular motion data such as the rotational angular velocity and angular acceleration of the hook 3 and the load it hangs in the space in real time, reflecting the change of the swing posture of the hanging object 6.
[0028] The laser rangefinder and gyroscope transmit the collected linear displacement data and angular motion data to the control system 4, which first processes the data and calibrates the timestamp to ensure the accuracy and synchronization of the data.
[0029] The control system 4 integrates the linear displacement data of the laser rangefinder and the angular motion data of the gyroscope; by comprehensively analyzing these two different types of data, the control system 4 can more comprehensively and accurately determine the real-time motion state of the suspended object 6, including parameters such as position, speed, acceleration, swing direction, swing amplitude, and angular velocity of the swing.
[0030] For example, when the laser rangefinder detects that the suspended object 6 has a certain displacement in the horizontal direction, and the gyroscope detects that the suspended object 6 has an angular velocity in the clockwise direction, the control system 4 can accurately calculate the actual motion trajectory and posture changes of the suspended object 6, and determine whether the suspended object 6 is in a stable lifting state or begins to swing due to external interference.
[0031] During the startup process, the hanging object 6 begins to swing slightly due to factors such as acceleration. The control system 4 accurately calculates the swing direction, amplitude and swing trend of the hanging object 6 based on the displacement change of the hanging object 6 fed back by the laser rangefinder and the angular motion data measured by the gyroscope.
[0032] Assuming that the suspended object 6 has an upward velocity component in the vertical direction and begins to swing to the left, the control system 4 will comprehensively consider the data of the laser rangefinder and the gyroscope, and not only control the vehicle body 1 to move to the left at a suitable speed to compensate for the horizontal displacement of the suspended object 6, but also adjust the rotation angle of the vehicle body 1 according to the angular velocity detected by the gyroscope if the vehicle body 1 has a rotation function, so that the movement of the vehicle body 1 is better synchronized with the swing of the suspended object 6, thereby more effectively avoiding further increase in the swing amplitude. At this stage, the control system 4 preliminarily adjusts the moving direction, speed and rotation angle of the vehicle body 1 according to the initial swing conditions provided by the laser rangefinder and the gyroscope, laying a solid foundation for subsequent stable lifting.
[0033] When the suspended object 6 approaches the target position, the laser rangefinder accurately measures the relative distance between the suspended object 6 and the target position and the swing state of the suspended object 6, and the gyroscope provides the angular motion information of the suspended object 6 at this time. The control system 4 plans the deceleration and stopping strategy of the vehicle body 1 in advance based on this comprehensive information.
[0034] If the hanging object 6 still has a certain swing at this time, the control system 4 will further finely adjust the moving direction, speed and rotation angle of the trolley body 1 on the premise of ensuring that the hanging object 6 can accurately reach the target position.
[0035] For example, if the suspended object 6 has a small leftward swing in the horizontal direction and has a certain clockwise angular velocity, the control system 4 will control the vehicle body 1 to move slowly to the left and rotate counterclockwise appropriately, while gradually reducing the speed until the suspended object 6 stops swinging and is just above the target position, thereby achieving safe and accurate lifting operations.
[0036] Through the coordinated work of the two sensors when approaching the target position, the swing of the suspended object 6 can be more strictly controlled to ensure accurate unloading.
[0037] like Figure 3 As shown, if the suspended object 6 lags behind the vehicle body 1 when the vehicle starts, the vehicle body 1 is braked. When the suspended object 6 swings forward and crosses the vertical line of the relative equilibrium position between it and the vehicle body 1, the vehicle body 1 is started again to follow the vehicle forward until the suspended object 6 and the vehicle body 1 run at the same speed.
[0038] When the vehicle body 1 starts, especially when it starts suddenly and shifts gears quickly, the vehicle body 1 has moved forward a distance S. The suspended object 6 is connected to the vehicle body 1 by a flexible steel wire rope or chain. Due to the inertia of the suspended object 6, it lags behind the vehicle body 1 by a distance S. Therefore, the suspended object 6 is relatively away from the original stable equilibrium position OG vertical line and swings.
[0039] The heavier the hanging object 6 and the faster the vehicle starts, the more serious the swing. Therefore, when the vehicle body 1 starts, it should be gradually accelerated to ensure stability, so as to reduce the swing of the hanging object 6. In addition, when the hanging object 6 is of large mass and the vehicle starts quickly, when the hanging object 6 lags behind the vehicle body 1 when starting, the brake should be applied in time, and when the hanging object 6 swings forward and crosses the vertical line OG of the relative equilibrium position between the hanging object 6 and the vehicle body 1, it should be started again to follow the vehicle forward immediately; under the joint action of the laser rangefinder and the gyroscope, by controlling the state of the hanging object 6 of the control system 4 and selecting the appropriate time and speed of following the vehicle, the vehicle body 1 and the hanging object 6 can be placed on the vertical line OG without relative movement, that is, running at the same speed, thereby eliminating the swing of the hanging object 6 when starting.
[0040] in, Figure 3 The O point shown is the lifting point of the crane, and the G point is the center of gravity of the hanging object 6.
[0041] like Figure 4 As shown, if the suspended object 6 swings back and forth relative to the vehicle body 1 after parking, the vehicle body 1 first follows the vehicle in the direction of the swing of the suspended object 6 until it stops at half of the maximum swing amplitude of the suspended object 6. When the suspended object 6 swings back, the vehicle body 1 is started again to follow the vehicle back until the vehicle body 1 and the suspended object 6 are on a vertical line in a relative equilibrium position.
[0042] If the vehicle body 1 has reached the predetermined parking place, but due to improper operation, excessive speed, too strong braking, etc., the hanging object 6 does not stop, but swings back and forth or left and right. In this case, it is extremely inappropriate to start dropping the hook to unload the hanging object 6. At this time, not only is the landing point of the hanging object 6 inaccurate, but it is also extremely unsafe and easy to cause an accident. At this time, the operation method of stabilizing the hook in situ can be adopted.
[0043] When the suspended object 6 swings forward, the vehicle body 1 is started to follow the vehicle forward to half of the maximum swing amplitude of the suspended object 6, and the vehicle body 1 is started to follow the vehicle backward when the suspended object 6 swings back; according to the braking condition of the vehicle body 1 and the data collected by the laser rangefinder and the gyroscope, the control system 4 can calculate the swing angle of the suspended object 6, and the suspended object 6 can be stabilized at the position where it should be parked by following the vehicle back and forth 1 to 2 times.
[0044] Among them, according to the laser rangefinder and the gyroscope, the maximum swing angle of the suspended object 6 can be measured as β, and the forward following distance Q and the return following distance T are calculated by the control system 4, that is, when the vehicle body 1 follows the vehicle forward for a distance Q at a certain speed, the swing angle α of the suspended object 6 is half of the maximum swing angle β, that is, α=β / 2; when the suspended object 6 swings back, the vehicle body 1 is started again to follow the vehicle back for a distance T, so that the suspended object 6 can be stabilized at the position where it should be parked.
[0045] If the suspended object 6 swings forward relative to the vehicle body 1 during operation, the speed of the vehicle body 1 is increased along the swing direction of the suspended object 6 so that the vehicle body 1 can keep up with the swing of the suspended object 6; when the suspended object 6 swings back, the speed of the vehicle body 1 is reduced so that the suspended object 6 can keep up with the operating angle of the vehicle body 1 to reduce the swing amplitude of the suspended object 6 until the vehicle body 1 and the suspended object 6 run smoothly at the same time.
[0046] When the object 6 swings forward during operation, the gear of the controller should be increased along the swing direction of the object 6 to increase the vehicle speed so that the vehicle body 1 can keep up with the swing of the hook 3; when the object 6 swings back, the gear of the controller should be reduced to reduce the vehicle speed so that the object 6 can keep up with the running angle of the vehicle body 1 to reduce the swing amplitude of the object 6. By repeatedly accelerating, decelerating and following the vehicle several times, the object 6 and the vehicle body 1 can run smoothly at the same time.
[0047] like Figure 5 As shown, although the hanging object 6 is very stable during startup and operation, if the parking method is not mastered well, the hanging object 6 will often swing during parking. At this time, the parking hook stabilization operation method can be used to eliminate the swing of the hanging object 6.
[0048] When the hanging object 6 is running smoothly, the relative speed between the hanging object 6 and the vehicle body 1 is zero, and they move at the same speed.
[0049] When the parking brake is applied when the suspended object 6 is about to reach the pre-stop position, the vehicle body 1 stops within a short distance due to mechanical braking, but the suspended object 6 connected to the vehicle body 1 by a flexible steel wire rope will still move forward at the initial speed before stopping due to inertia, causing the suspended object 6 to produce a forward and backward (or left and right) swinging motion with the hanging point O as the center of the circle, the distance between the hanging point 0 and the center of gravity G of the suspended object 6 as the radius, and the plumb line 0G as the axis of symmetry.
[0050] The method to eliminate this swaying is to brake appropriately 1 to 2 times within a certain distance from the vehicle body 1 to the predetermined parking position. When the suspended object 6 swings in the forward direction, immediately follow the vehicle 1 to 2 times to steadily stop the suspended object 6 at the predetermined parking location.
[0051] in, Figure 3From left to right, the schematic diagrams are the deceleration of the vehicle body 1, parking brake, instantaneous following and sliding following; that is, the vehicle body 1 is braked before the predetermined parking position, and when the suspended object 6 swings in the forward direction, the vehicle is immediately instantaneously followed until the suspended object 6 stops steadily at the predetermined parking position.
[0052] In summary, the distance change of the suspended object 6 relative to the vehicle body 1 in the horizontal and vertical directions is obtained through the distance measuring component 5, and the angular velocity and angular acceleration of the swing of the suspended object 6 in space are obtained through the gyroscope, and then the real-time motion state of the suspended object 6 is determined by the control system 4, which provides reliable data support for eliminating the swing of the suspended object 6 and greatly reduces the difficulty of eliminating the swing for the operator.
[0053] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.
[0054] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.
[0055] The above is based on the ideal embodiment of the present invention. Through the above description, relevant personnel can make various changes and modifications without departing from the technical concept of the present invention. The technical scope of the present invention is not limited to the content in the specification, and the technical scope must be determined according to the scope of the claims.
Claims
1. A crane, comprising a body (1) mounted on a bridge, an electric hoist (2) mounted on the body (1), a hook (3) for hoisting a load (6) connected to the bottom of the electric hoist (2) via a rope, and a control system (4) disposed on one side of the body (1), characterized in that: It also includes a distance measuring component (5) for measuring the linear displacement change of the hanging object (6) and a gyroscope for monitoring the swing posture change of the hanging object (6), wherein the distance measuring component (5) is mounted on the vehicle body (1) and the gyroscope is mounted on the hook (3).
2. The crane and the method for eliminating swing thereof according to claim 1, characterized in that: The distance measuring component (5) is used to measure the displacement change of the hanging object (6) relative to the vehicle body (1), and the distance measuring component (5) adopts a laser rangefinder.
3. A method for eliminating crane swing according to any one of claims 1 to 2, characterized in that: The linear displacement data of the suspended object (6) is obtained through the distance measuring component (5), and the angular motion data of the suspended object (6) in space is obtained through the gyroscope; the collected data is transmitted to the control system (4), and the control system (4) comprehensively analyzes the two types of data to determine the real-time motion state of the suspended object (6); and the motion state of the vehicle body (1) is adjusted accordingly according to the motion state of the suspended object (6) to ensure that the suspended object (6) is in a stable lifting state.
4. The method for eliminating crane swing according to claim 3, characterized in that: The linear displacement data include the change in distance of the suspended object (6) relative to the vehicle body (1) in the horizontal and vertical directions, and the angular motion data include the angular velocity and angular acceleration of the suspended object swinging in space.
5. The method for eliminating crane swing according to claim 4, characterized in that: After receiving the linear displacement data and angular motion data of the suspended object (6), the control system (4) first pre-processes the data; the pre-processing includes calibrating the timestamp to ensure the accuracy and synchronization of the data.
6. The method for eliminating crane swing according to claim 3, characterized in that: If the suspended object (6) lags behind the vehicle body (1) when the vehicle is started, the vehicle body (1) is braked, and when the suspended object (6) swings forward and crosses the vertical line of the relative equilibrium position between it and the vehicle body (1), the vehicle body (1) is started again to follow the vehicle forward until the suspended object (6) and the vehicle body (1) run at the same speed.
7. The method for eliminating crane swing according to claim 3, characterized in that: The vehicle body (1) brakes before reaching a predetermined parking position, and when the suspended object (6) swings in the forward direction, the vehicle body immediately moves in an instant to follow the vehicle until the suspended object (6) stops steadily at the predetermined parking position.
8. The method for eliminating crane swing according to claim 7, characterized in that: If the suspended object (6) swings forward and backward relative to the vehicle body (1) after the vehicle stops, the vehicle body (1) first follows the vehicle in the direction of the swing of the suspended object (6) until it reaches half of the maximum swing amplitude of the suspended object (6) and then stops. When the suspended object (6) swings back, the vehicle body (1) is started to follow the vehicle back until the vehicle body (1) and the suspended object (6) are on a vertical line at a relative equilibrium position.
9. The method for eliminating crane swing according to claim 3, characterized in that: If the suspended object (6) swings forward relative to the vehicle body (1) during operation, the speed of the vehicle body (1) is increased along the swing direction of the suspended object (6) so that the vehicle body (1) keeps up with the swing of the suspended object (6); when the suspended object (6) swings back, the speed of the vehicle body (1) is reduced so that the suspended object (6) keeps up with the running angle of the vehicle body (1) to reduce the swing amplitude of the suspended object (6) until the vehicle body (1) and the suspended object (6) run smoothly at the same time.