Hoisting mechanism ascending and descending control method and control system

Abstract

The application discloses a rising and falling control method and a control system of a portal crane hoisting mechanism, wherein the falling control method is provided with a falling dynamic height value, a falling deceleration detection position and a falling stop detection position, and the rising control method is provided with a rising dynamic height value, a rising deceleration detection position and a rising stop detection position. The rising and falling control method and the control system can improve the loading and unloading efficiency and are safe.

Description

Technical Field

[0001] This invention relates to the field of gantry cranes, and more specifically, to a method and control system for controlling the raising and lowering of a hoisting mechanism. Background Technology

[0002] Gantry cranes are widely used in port terminal loading and unloading operations. They are primarily used for lifting and transporting containers, such as moving containers from the yard to container trucks, or vice versa. Containers are typically mounted on the spreader of the gantry crane's hoisting mechanism. The movement of the spreader moves the container, involving both lifting and lowering. Due to the weight of both the spreader and the container, the lifting and lowering speeds are relatively slow for safety reasons, resulting in lower overall loading and unloading efficiency. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a descent control method for the hoisting mechanism of a gantry crane, which can shorten the descent time of the lifting device, improve the overall loading and unloading efficiency, and also has good safety.

[0004] The descent control method for the hoisting mechanism of the gantry crane of the present invention includes:

[0005] The first initial height information of the hoisting mechanism's spreader is obtained, and the first initial height information is compared with the dynamic descent height value. If the first initial height information is greater than the dynamic descent height value, the spreader is controlled to accelerate downward movement.

[0006] During the descent of the spreader, the real-time height information of the spreader is acquired in real time, and the real-time height information is compared with the dynamic descent height value. When the real-time height information is equal to or less than the dynamic descent height value, the spreader is controlled to decelerate.

[0007] During the continued descent of the spreader, when it is known that the spreader has passed the descent deceleration detection position, the descent speed information of the spreader at this time is obtained and compared with a first preset speed value. If the descent speed information is greater than the first preset speed value, the spreader is controlled to stop descending. If the descent speed information is equal to or less than the first preset speed value, the spreader is allowed to continue descending.

[0008] During the continued descent of the lifting device, when it is detected that the lifting device has passed the descent stop detection position, the lifting device is controlled to stop descent;

[0009] The dynamic descent height value is greater than the height of the descent deceleration detection position, and the height of the descent deceleration detection position is greater than the height of the descent stop detection position.

[0010] Furthermore, the dynamic descent height value is P1, where P1 = PjD + Sd - Smax.

[0011] PjD is the descent baseline value, Sd is the deceleration distance required for the spreader to slow down to a stop at the current speed, and Smax is the maximum deceleration distance of the spreader.

[0012] Furthermore,

[0013] The maximum deceleration distance of the spreader is calculated by the following formula: Smax=(1 / 2Vmax)*Tmax;

[0014] The deceleration distance required for the spreader to slow down to a stop from its current speed is calculated by the following formula: Sd=Vd*Vd*Tmax / (2Vmax);

[0015] Vmax is the maximum speed of the hoisting mechanism, Tmax is the longest deceleration time of the hoisting mechanism, and Vd is the current speed of the spreader.

[0016] The present invention also proposes a lowering control system for the hoisting mechanism of a gantry crane, including a memory and a processor. The memory stores a computer program, and when the computer program is executed by the processor, it implements the lowering control method.

[0017] Furthermore, it also includes a height detection unit, a speed detection unit, a first position sensor, and a second position sensor, all of which are connected to the processor.

[0018] The descent control method and control system of the gantry crane hoisting mechanism of the present invention, by setting a dynamic descent height value, allows the lifting device to descend at a faster speed above the dynamic descent height value, shortening the descent time. After reaching the dynamic descent height value position, the device decelerates. Furthermore, by setting a descent deceleration detection position and a descent stop detection position, the device is ensured to stop in a timely manner, ensuring the safety of the descent. Therefore, the descent control method and control system can both shorten the descent time of the lifting device, improve loading and unloading efficiency, and ensure safety.

[0019] This invention also proposes a method for controlling the lifting mechanism of a gantry crane, comprising:

[0020] The second initial height information of the hoisting mechanism's spreader is obtained, and the second initial height information is compared with the dynamic upward height value. If the second initial height information is less than the dynamic upward height value, the spreader is controlled to accelerate upward movement.

[0021] During the ascent of the spreader, the real-time height information of the spreader is acquired in real time, and the real-time height information is compared with the dynamic ascent height value. When the real-time height information is equal to or greater than the dynamic ascent height value, the spreader is controlled to decelerate.

[0022] During the continued ascent of the lifting device, when it is known that the lifting device has passed the deceleration detection position, the lifting speed information of the lifting device at this time is obtained, and the lifting speed information is compared with a second preset speed value. If the lifting speed information is greater than the second preset speed value, the lifting device is controlled to stop rising. If the lifting speed information is equal to or less than the second preset speed value, the lifting device is allowed to continue rising.

[0023] During the continued ascent of the lifting device, when it is detected that the lifting device has passed the ascent stop detection position, the lifting device is controlled to stop ascending;

[0024] The rising dynamic height value is less than the height of the rising deceleration detection position, and the height of the rising deceleration detection position is less than the height of the rising stop detection position.

[0025] Furthermore, the dynamic height value is P2, where P2 = PjU + Smax - Sd.

[0026] PjU is the reference value for ascent, Sd is the deceleration distance required for the spreader to slow down to a stop at the current speed, and Smax is the maximum deceleration distance of the spreader.

[0027] Furthermore,

[0028] The maximum deceleration distance of the spreader is calculated by the following formula: Smax=(1 / 2Vmax)*Tmax;

[0029] The deceleration distance required for the spreader to slow down to a stop from its current speed is calculated by the following formula: Sd=Vd*Vd*Tmax / (2Vmax);

[0030] Vmax is the maximum speed of the hoisting mechanism, Tmax is the longest deceleration time of the hoisting mechanism, and Vd is the current speed of the spreader.

[0031] The present invention also proposes a lifting control system for a gantry crane lifting mechanism, including a memory and a processor. The memory stores a computer program, and when the computer program is executed by the processor, it implements the lifting control method.

[0032] Furthermore, it also includes a height detection unit, a speed detection unit, a third position sensor, and a fourth position sensor, all of which are connected to the processor.

[0033] The lifting control method and lifting control system of the gantry crane hoisting mechanism of the present invention, by setting a dynamic lifting height value, allows the lifting device to rise at a faster speed below the dynamic lifting height value, shortening the lifting time. After reaching the dynamic lifting height value, the lifting device decelerates. Furthermore, by setting a lifting deceleration detection position and a lifting stop detection position, the lifting device is ensured to stop in a timely manner, ensuring the safety of the lifting device's ascent. Therefore, the lifting control method and lifting control system can both shorten the lifting time of the lifting device, improve loading and unloading efficiency, and ensure safety. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a gantry crane according to an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the detection and calibration positions in the height direction in an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram showing the installation positions of the measuring disk and various position sensors in an embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of the descent control system according to an embodiment of the present invention;

[0038] Figure 5 This is a schematic diagram of the lifting control system according to an embodiment of the present invention. Detailed Implementation

[0039] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar units or units having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0040] In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the structure or unit referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. In the description of this specification, the terms "installation," "setting," "connection," etc., should be interpreted broadly, and can refer to direct installation, setting, or connection, or indirect installation, setting, or connection. "Connection" can be a mechanical connection, an electrical connection, or a transmission connection for realizing power transmission.

[0041] The following is for reference. Figure 1-5 The present invention describes an ascent control method, a descent control method, an ascent control system, and a descent control system according to embodiments of the present invention.

[0042] The following equipment is typically involved in container terminal yard loading and unloading operations:

[0043] 1. Container truck: A container truck used for transporting containers in a yard. It needs to work with a gantry crane to complete the lifting process.

[0044] 2. Truck Lane within the Yard: This is a straight road for trucks to travel on. The truck lane is located within the span of the gantry crane, near the electrical room. Trucks wait in the lane for the gantry crane to load and unload containers, and must leave the truck lane immediately after loading and unloading is completed.

[0045] 3. Gantry cranes: Cranes with a frame structure, including:

[0046] 1) Trolley: It consists of two sets of gate legs and a pair of crossbeams 11 mounted on top of the gate legs, and is called "trolley". During container loading and unloading operations, the side closer to the electrical room is called the electrical room side and the side closer to the engine is called the engine side. Each set of gate legs includes two gate posts 12 on the left and right. Rubber tires are installed under the gate posts. During operation, it travels on the ground in a direction parallel to the container truck lane.

[0047] 2) Trolley: The main beam of the gantry crane is covered with steel rails and a wheel-rail traveling mechanism is installed to allow it to travel along the beam direction. This mechanism is called the "trolley". The trolley is equipped with a driver's cab, in which the gantry crane operator operates the crane to complete the receiving and dispatching of containers.

[0048] 3) Lifting Mechanism 13: The lifting mechanism 13 includes a frequency converter, AC motor, brake, electrical control system, and spreader 131. The lifting mechanism 13 is responsible for the lifting and lowering of containers during loading and unloading operations and is an important component of the gantry crane. A spreader 131 is mounted on the trolley via wire rope. During container loading and unloading operations, the trolley moves the spreader 131 above the container ship. The spreader 131 is raised and lowered by extending and retracting the wire rope, and then lowered onto the container on the ship to complete the container handling operation. The main beam of the spreader 131 has two pairs of telescopic horizontal booms. The bottom of the booms has rotatable locking pins at both ends and the middle. The spreader 131 extends and retracts the booms according to the container type, aligning the locking pins with the locking holes on the top of the container. Inserting the locking pins into the locking holes and rotating them securely connects them to the container, enabling the lifting and transport of the container.

[0049] A descent control method for a gantry crane hoisting mechanism 13 according to an embodiment of the present invention includes the following steps: obtaining first initial height information of the lifting device 131 of the hoisting mechanism 13, and comparing the first initial height information with the descent dynamic height value; if the first initial height information is greater than the descent dynamic height value, then causing the lifting device 131 to move downward at an accelerated speed.

[0050] Normally, the spreader 131 is initially stationary. Before lowering the spreader 131, its initial position information (first initial height information) needs to be acquired. If the initial height is greater than the dynamic descent height value, it indicates that the position of the spreader 131 is safe, and the hoisting mechanism 13 can be activated to accelerate the downward movement of the spreader 131. During the accelerated downward movement of the spreader 131, once it reaches the maximum descent speed, it continues to descend at that maximum speed. The maximum descent speed is related to the load on the spreader 131, such as whether it is unloaded or carrying containers of different weights. The maximum descent speed varies depending on the load. For example, in some cases, the larger the load, the lower the maximum speed. During the downward movement of the spreader 131, its real-time height information needs to be acquired and compared with the dynamic descent height value. When the real-time height information is equal to or less than the dynamic descent height value, the spreader 131 is decelerated. It should be noted that before the lifting device 131 decelerates, its descent speed may or may not have reached the maximum speed for this descent. Then, the lifting device 131 begins to decelerate and descend. During this deceleration, when the lifting device 131 passes the deceleration detection position H1, it acquires the descent speed information of the lifting device 131 at this time and compares it with a first preset speed value. If the descent speed of the lifting device 131 is greater than the first preset speed value, it controls the lifting device 131 to stop descending. If the descent speed of the lifting device 131 is equal to or less than the first preset speed value, it allows the lifting device 131 to continue moving downwards. During the continued descent, when the lifting device 131 passes the descent stop detection position H2, it controls the lifting device 131 to stop. The dynamic descent height value is greater than the height of the deceleration detection position H1, and the height of the deceleration detection position H1 is greater than the height of the descent stop detection position H2.

[0051] In this embodiment of the invention, a dynamic descent height value, a descent deceleration detection position H1, and a descent stop detection position H2 are set. When the lifting device 131 descends to the dynamic descent height value, it begins to decelerate. When the lifting device 131 continues to descend to the descent deceleration detection position H1, the real-time descent speed of the lifting device 131 is detected. If the descent speed of the lifting device 131 is greater than a first preset speed value, it indicates that the descent speed of the lifting device 131 is too fast and there is a risk of collision with the object below or the ground. Therefore, the lifting device 131 is controlled to stop. If the descent speed of the lifting device 131 is equal to or less than the first preset speed value, it indicates that the speed of the lifting device 131 at this time is safe, and the lifting device 131 can continue to descend. After the lifting device 131 reaches the descent stop detection position H2, it is controlled to stop.

[0052] In this embodiment of the invention, when the spreader 131 is above the dynamic descent height value, it can move downwards at its maximum descent speed, thus reducing descent time and improving loading and unloading efficiency. Once the spreader 131 reaches the dynamic descent height value, it needs to decelerate for safety reasons. By setting the dynamic descent height value, the deceleration detection position H1, and the stop descent detection position H2, the deceleration process of the spreader 131 can be reliably controlled to prevent collisions between the spreader 131 (or the spreader 131 and the container) and objects below or the ground, thereby improving the safety of the spreader 131's descent. Therefore, this invention reduces the descent time of the spreader 131 while ensuring safety, thus improving efficiency.

[0053] The height information of the lifting device 131 can be detected by the height detection unit and can be obtained from the height detection unit at any time. For example, the control unit obtains the initial height information or real-time height information of the lifting device 131 from the height detection unit. The height detection unit can be a position encoder or a combination of a position encoder and other components. The position encoder can be pre-installed in the hoisting mechanism 13, for example, installed on an AC motor or reducer and connected to the output shaft of the AC motor or reducer. There is a certain relationship between the rotation angle of the AC motor or reducer and the rising or falling distance of the lifting device 131. This relationship can be obtained through theoretical calculation or experimentation. By detecting the rotation angle of the output shaft of the AC motor or reducer, the height position information of the lifting device can be detected. The descent speed information of the lifting device 131 can be obtained from the speed detection unit. The speed detection unit can be a speed encoder or a combination of a speed encoder and other components. The speed encoder can be pre-installed in the hoisting mechanism 13, for example, installed on the AC motor or reducer and connected to the output shaft of the AC motor or reducer. Since there is a certain relationship between the rotation speed of the output shaft of the AC motor or reducer and the rising or falling speed of the lifting device 131, this relationship can be obtained through theoretical calculation or experiment. By detecting the rotation speed of the output shaft of the AC motor or reducer, the rising or falling speed of the lifting device can be detected.

[0054] In one embodiment, the dynamic descent height value is P1, which can be calculated by the following formula:

[0055] P1 = PjD + Sd - Smax,

[0056] PjD is the descent baseline value, Sd is the deceleration distance required for the spreader to slow down to a stop at the current speed, where the current speed refers to the descent speed before the spreader decelerates, and Smax is the maximum deceleration distance of the spreader.

[0057] The descent reference value PjD is related to the mechanical structure and spreader structure of the gantry crane, and safety factors are taken into account. It can be measured on-site and then input into the control unit. It should be noted that the descent reference value is different in two scenarios: spreader unlocked (spreader unloaded) and spreader locked (spreader lifting a container). The descent reference value is set to PjDL when unlocked and PjDUL when locked. For example, for a gantry crane and spreader, PjDL = 6.6 meters and PjDUL = 7.5 meters.

[0058] The maximum deceleration distance of the spreader is calculated using the following formula:

[0059] Smax = (1 / 2Vmax) * Tmax,

[0060] Vmax is the maximum speed of the hoisting mechanism (spreader) set by the system, and Tmax is the maximum deceleration time of the hoisting mechanism (spreader) set by the system. These two parameters are preset and stored in the control unit.

[0061] The deceleration distance required for the spreader to come to a stop from its current speed is calculated using the following formula:

[0062] Sd=Vd*Vd*Tmax / (2Vmax),

[0063] Vd is the current speed of the spreader, which can be obtained from the speed detection unit.

[0064] As can be seen from the above formula, the magnitude of the dynamic descent height value P1 is related to the current speed Vd of the spreader 131, and the correlation is positive; that is, the larger the current speed Vd of the spreader 131, the larger the dynamic descent height value P1. In this embodiment of the invention, the dynamic descent height value varies with the current speed of the spreader 131 and is not a fixed value. This allows the dynamic descent height value to be adjusted in real time according to the load conditions of the spreader 131 each time. Under various load conditions, the spreader 131 can descend quickly, thereby improving loading and unloading efficiency and ensuring safety.

[0065] Both the descent deceleration detection position H1 and the descent stop detection position H2 are at a certain height above the ground, with the descent deceleration detection position H1 being higher than the descent stop detection position H2. The descent deceleration detection position H1 and the descent stop detection position H2 can be predetermined and stored in the control unit, therefore, the descent deceleration detection position H1 and the descent stop detection position H2 will not change with different loads on the lifting device 131.

[0066] After determining the descent deceleration detection position H1, a first position sensor can be installed at H1. For example, the first position sensor can be installed at the height corresponding to the descent deceleration detection position H1 on the gantry of a gantry crane. A sensing element corresponding to the first position sensor can be installed on the lifting device 131. When the lifting device 131 rises or falls near the gantry, if the lifting device 131 passes the first position sensor, the first position sensor will detect the sensing element and output a sensing signal to the control unit. After receiving the sensing signal, the control unit indicates that the lifting device 131 has passed the descent deceleration detection position H1, that is, the control unit knows that the lifting device 131 has passed the descent deceleration detection position H1. The first position sensor can be an electromagnetic sensor; its specific working principle will not be described in detail in this invention.

[0067] Alternatively, a first position sensor can be installed at position A1 corresponding to the descent deceleration detection position H1. Specifically, a detection reducer and a measuring disk 15 can be set up. The measuring disk 15 has a notch or a circular hole on its outer edge. The input shaft of the detection reducer is connected to the output shaft of the AC motor or reducer of the hoisting mechanism 13. The measuring disk 15 is fixedly mounted on the output shaft of the detection reducer. When the AC motor or reducer rotates, it drives the detection reducer to rotate. The reduction ratio of the detection reducer is set so that during the process of the lifting device 131 moving from the lowest point below the gantry crane to the highest point above, the rotation angle of the output shaft of the position reducer is less than or equal to one revolution, i.e., the measurement... The rotation angle of the disc 15 is less than or equal to one revolution. The first position sensor can be a photoelectric sensor, which is installed at a set position on the circumference of the measuring disc 15 and is opposite to the measuring disc 15 (the photoelectric sensor is not installed on the measuring disc 15 and does not rotate with the measuring disc 15). This set position corresponds to the descent deceleration detection position H1. During the rotation of the measuring disc 15, when the notch or hole passes through the photoelectric sensor, the photoelectric sensor outputs a sensing signal. After the control unit receives the sensing signal, it indicates that the lifting device 131 has passed the descent deceleration detection position H1. The set position can be predetermined.

[0068] After the descent stop detection position H2 is determined, a second position sensor can be installed at the descent stop detection position H2, or at the position A2 corresponding to the descent stop detection position H2. The type of the second position sensor is the same as or similar to that of the first position sensor, and the installation method of the second position sensor is similar to that of the first position sensor.

[0069] In this embodiment of the invention, the detection of the descent deceleration detection position H1 and the descent stop detection position H2 of the lifting device 131 is achieved through a first position sensor and a second position sensor, without relying on a position encoder. This eliminates concerns about encoder errors or malfunctions, enhancing the safety and reliability of the descent control method. It should be noted that in this embodiment of the invention, all heights are relative to the ground level and refer upwards.

[0070] A descent control system for the hoisting mechanism of a gantry crane according to an embodiment of the present invention includes a memory and a processor. The memory stores a computer program, which, when executed by the processor, implements the aforementioned descent control method. The memory and processor can be part of a control unit, i.e., the control unit may include the memory and the processor. Specifically, the descent control system further includes a height detection unit, a speed detection unit, a first position sensor, and a second position sensor, all of which are connected to the processor. The processor acquires first initial height information and real-time height information of the lifting device 131 through the height detection unit, acquires descent speed information of the lifting device 131 through the speed detection unit, determines through the first position sensor that the lifting device 131 has passed the descent deceleration detection position H1, and determines through the second position sensor that the lifting device 131 has passed the descent stop detection position H2.

[0071] An embodiment of the present invention provides a method for controlling the lifting mechanism of a gantry crane, comprising the following steps: obtaining second initial height information of the lifting device 131 of the lifting mechanism, and comparing the second initial height information with the dynamic lifting height value; if the second initial height information is less than the dynamic lifting height value, then accelerating the lifting device 131 upward.

[0072] Normally, the spreader 131 is initially stationary. Before raising the spreader 131, its initial position information (second initial height information) must be obtained. If the initial height is less than the dynamic lifting height value, it indicates that the position of the spreader 131 is safe, and the hoisting mechanism 13 can be activated to accelerate the spreader 131 upwards. During the upward acceleration, once the spreader 131 reaches its maximum lifting speed, it continues to rise at that speed. The maximum lifting speed is related to the load on the spreader 131. For example, the maximum lifting speed will differ depending on whether the spreader 131 is unloaded or carrying containers of different weights.

[0073] During the upward movement of the spreader 131, real-time height information of the spreader 131 needs to be acquired and compared with the dynamic upward height value. When the real-time height information is equal to or greater than the dynamic upward height value, the spreader 131 is decelerated. It should be noted that before the spreader 131 decelerates, its upward speed may or may not have reached the maximum speed for this ascent. Then, the spreader 131 begins to decelerate and ascend. During this deceleration, when the spreader 131 passes the deceleration detection position H3, its upward speed information is acquired and compared with a second preset speed value. If the upward speed of the spreader 131 is greater than the second preset speed value, the spreader 131 is controlled to stop ascending. If the upward speed of the spreader 131 is equal to or less than the second preset speed value, the spreader 131 continues to move upward. During the continued ascent, when the spreader 131 passes the stop detection position H4, the spreader 131 is controlled to stop. The dynamic height value of the ascent is less than the height of the ascent deceleration detection position H3, and the height of the ascent deceleration detection position H3 is less than the height of the ascent stop detection position H4.

[0074] In this embodiment of the invention, a dynamic lifting height value, a lifting deceleration detection position H3, and a lifting stop detection position H4 are set. When the lifting device 131 rises to the dynamic lifting height value, the lifting device 131 begins to decelerate. When the lifting device 131 continues to rise to the lifting deceleration detection position H3, the real-time lifting speed of the lifting device 131 is detected. If the lifting speed of the lifting device 131 is greater than a second preset speed value, it indicates that the lifting speed of the lifting device 131 is too fast and there is a risk of collision with the object above or the top of the gantry crane. Therefore, the lifting device 131 is controlled to stop. If the lifting speed of the lifting device 131 is equal to or less than the second preset speed value, it indicates that the speed of the lifting device 131 at this time is safe, and the lifting device 131 can continue to rise. After the lifting device 131 reaches the lifting stop detection position H4, the lifting device 131 is controlled to stop.

[0075] The first and second preset speed values ​​can be determined in advance, for example, through experiments and by considering safety factors. Once determined, they can be stored in the control unit.

[0076] In this embodiment of the invention, when the spreader 131 is below the dynamic lifting height value, it can move upward at its maximum lifting speed, thus reducing lifting time and improving loading and unloading efficiency. Once the spreader 131 reaches the dynamic lifting height value, it needs to decelerate for safety reasons. By setting the dynamic lifting height value, the deceleration detection position H3, and the stop lifting detection position H4, the deceleration process of the spreader 131 can be reliably controlled, preventing collisions between the spreader 131 (or the spreader 131 and the container) and the objects above it or the top of the gantry crane, thereby improving the safety of the spreader 131's ascent. Therefore, this invention reduces the lifting time of the spreader 131 while ensuring safety, thus improving efficiency.

[0077] The height information of the spreader 131 can be detected by the height detection unit and can be obtained from the height detection unit at any time. For example, the control unit can obtain the second initial height information or real-time height information of the spreader 131 from the height detection unit, and the lifting speed information of the spreader 131 can be obtained from the speed detection unit.

[0078] In one embodiment, the dynamic height of ascent is P2, which can be calculated by the following formula:

[0079] P2, P2=PjU+Smax-SdPjU is the reference value for ascent, Sd is the deceleration distance required for the spreader to decelerate to a stop at the current speed, the current speed refers to the ascent speed of the spreader before deceleration, and Smax is the maximum deceleration distance of the spreader.

[0080] The lifting reference value PjU is related to the mechanical structure and spreader structure of the gantry crane, and safety factors are taken into account. It can be measured on-site and then input into the control unit. It should be noted that the lifting reference value is different in two scenarios: spreader unlocked (spreader unloaded) and spreader locked (spreader lifting a container). The lifting reference value is set to PjUL when unlocked and PjDUL when locked. For example, for a gantry crane and spreader, PjUL = 18.7 meters and PjUUL = 18.8 meters.

[0081] As can be seen from the above formula, the dynamic lifting height value P2 is related to the current speed Vd of the spreader 131, and inversely related; that is, the larger the current speed Vd of the spreader 131, the smaller the dynamic lifting height value P1. In this embodiment of the invention, the dynamic lifting height value varies with the current speed of the spreader 131 and is not a fixed value. This allows the dynamic lifting height value to be adjusted in real time according to the load condition of the spreader 131 each time. Under various load conditions, the spreader 131 can rise quickly, thereby improving loading and unloading efficiency and ensuring safety.

[0082] Both the upward deceleration detection position H3 and the upward stop detection position H4 are at a certain height above the ground, with the upward deceleration detection position H3 being lower than the upward stop detection position H4. The upward deceleration detection position H3 and the upward stop detection position H4 can be predetermined and stored in the control unit, therefore, the upward deceleration detection position H3 and the upward stop detection position H4 will not change with different loads on the lifting device 131.

[0083] After determining the upward deceleration detection position H3, a third position sensor can be installed at H3. For example, the third position sensor can be installed at the height corresponding to the upward deceleration detection position H3 on the gantry crane's column. A sensing element corresponding to the third position sensor can be installed on the spreader 131. When the spreader 131 rises or falls at a certain distance from the gantry, if the spreader 131 passes the third position sensor, the third position sensor will detect the sensing element and output a sensing signal to the control unit. After receiving the sensing signal, the control unit will know that the spreader 131 has passed the upward deceleration detection position H3. The third position sensor can be an electromagnetic sensor.

[0084] Alternatively, a third position sensor can be installed at position A3 corresponding to the upward deceleration detection position H3. This third position sensor can be a photoelectric sensor, and its specific configuration is the same as that of the first position sensor. After the upward stop detection position H4 is determined, a fourth position sensor can be installed at H4, or at position A4 corresponding to H4. The type of the fourth position sensor is the same as or similar to that of the first position sensor, and its installation method is similar to that of the first position sensor.

[0085] In this embodiment of the invention, the detection of the lifting device 131 passing through the ascending deceleration detection position H3 and the ascending stop detection position H4 is achieved through a third position sensor and a fourth position sensor, without relying on a position encoder. This eliminates concerns about encoder errors or malfunctions, enhancing the safety and reliability of the lifting control method. An embodiment of the lifting control system for the gantry crane lifting mechanism 13 of this invention includes a memory and a processor. The memory stores a computer program, which, when executed by the processor, implements the aforementioned lifting control method. The memory and processor can be part of a control unit; that is, the control unit may include the memory and the processor. Specifically, the lifting control system further includes a height detection unit, a speed detection unit, a third position sensor, and a fourth position sensor, all of which are connected to the processor. The processor obtains the second initial height information and real-time height information of the lifting device 131 through the height detection unit, obtains the ascending speed information of the lifting device 131 through the speed detection unit, determines that the lifting device 131 has passed the ascending deceleration detection position H3 through the third position sensor, and determines that the lifting device 131 has passed the ascending stop detection position H4 through the fourth position sensor.

[0086] In this embodiment of the invention, the descent control system and the ascent control system can share a control unit, that is, share a memory and a processor.

[0087] In one specific embodiment, the lifting control system further includes a fifth position sensor, which can be an electromagnetic sensor or a photoelectric sensor. The fifth position sensor can be installed at a calibration position H5 (e.g., a suitable position on the gantry of a gantry crane) or at a position A5 corresponding to the calibration position H5 (e.g., a suitable position in the circumferential direction of the measuring disk 15). The calibration position H5 can be used to correct the error of the position encoder. During long-term operation, the position encoder will develop certain errors, which can be corrected through the calibration position H5. In the height direction, the calibration position H5 is located between the lifting deceleration detection position H3 and the descent deceleration detection position H1.

[0088] Specifically, firstly, a calibration position H5 is selected, and its height information is measured. This height information is pre-stored in the control unit. When the lifting device 131 passes the calibration position H5, the fifth position sensor detects it and outputs a sensing signal to the control unit. Upon receiving the sensing signal, the control unit compares the height information fed back by the position encoder at this moment with the pre-stored height information of the calibration position H5 to correct the position encoder error. If the fifth position sensor is installed at the position corresponding to the calibration position H5, when the lifting device 131 passes the calibration position H5, the notch or hole of the measuring disk 15 passes through the fifth position sensor, and the fifth position sensor outputs a sensing signal to the control unit. Upon receiving the sensing signal, the control unit compares the height information fed back by the position encoder at this moment with the pre-stored height information of the calibration position H5 to correct the position encoder error.

[0089] In one specific embodiment, the descent control system further includes a lateral position encoder connected to the control unit (or processor). The lateral position encoder is used to detect the lateral position of the trolley or hoisting mechanism 13 and adjust the descent control method according to the different lateral positions. Lateral refers to the direction along the crossbeam of the gantry crane.

[0090] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for controlling the descent of a gantry crane's hoisting mechanism, characterized in that, include: The first initial height information of the hoisting mechanism's spreader is obtained, and the first initial height information is compared with the dynamic descent height value. If the first initial height information is greater than the dynamic descent height value, the spreader is controlled to accelerate downward movement. During the descent of the spreader, the real-time height information of the spreader is acquired in real time, and the real-time height information is compared with the dynamic descent height value. When the real-time height information is equal to or less than the dynamic descent height value, the spreader is controlled to decelerate. During the continued descent of the spreader, when it is known that the spreader has passed the descent deceleration detection position, the descent speed information of the spreader at this time is obtained and compared with a first preset speed value. If the descent speed information is greater than the first preset speed value, the spreader is controlled to stop descending. If the descent speed information is equal to or less than the first preset speed value, the spreader is allowed to continue descending. During the continued descent of the lifting device, when it is detected that the lifting device has passed the descent stop detection position, the lifting device is controlled to stop descent; The dynamic descent height value is greater than the height of the descent deceleration detection position, and the height of the descent deceleration detection position is greater than the height of the descent stop detection position. The dynamic descent height value is P1, where P1 = PjD + Sd - Smax, PjD is the descent baseline value, Sd is the deceleration distance required for the spreader to slow down to a stop at the current speed, and Smax is the maximum deceleration distance of the spreader.

2. The descent control method as described in claim 1, characterized in that, The maximum deceleration distance of the spreader is calculated by the following formula: Smax = (1 / 2 Vmax) * Tmax; The deceleration distance required for the spreader to slow down to a stop from its current speed is calculated by the following formula: Sd = Vd * Vd * Tmax / (2Vmax); Vmax is the maximum speed of the hoisting mechanism, Tmax is the longest deceleration time of the hoisting mechanism, and Vd is the current speed of the spreader.

3. A lowering control system for the hoisting mechanism of a gantry crane, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program that, when executed by the processor, implements the descent control method according to any one of claims 1-2.

4. The descent control system as described in claim 3, characterized in that, It also includes a height detection unit, a speed detection unit, a first position sensor, and a second position sensor, all of which are connected to the processor.

5. A method for controlling the lifting mechanism of a gantry crane, characterized in that, include: The second initial height information of the hoisting mechanism's spreader is obtained, and the second initial height information is compared with the dynamic upward height value. If the second initial height information is less than the dynamic upward height value, the spreader is controlled to accelerate upward movement. During the ascent of the spreader, the real-time height information of the spreader is acquired in real time, and the real-time height information is compared with the dynamic ascent height value. When the real-time height information is equal to or greater than the dynamic ascent height value, the spreader is controlled to decelerate. During the continued ascent of the lifting device, when it is known that the lifting device has passed the deceleration detection position, the lifting speed information of the lifting device at this time is obtained, and the lifting speed information is compared with a second preset speed value. If the lifting speed information is greater than the second preset speed value, the lifting device is controlled to stop rising. If the lifting speed information is equal to or less than the second preset speed value, the lifting device is allowed to continue rising. During the continued ascent of the lifting device, when it is detected that the lifting device has passed the ascent stop detection position, the lifting device is controlled to stop ascending; The rising dynamic height value is less than the height of the rising deceleration detection position, and the height of the rising deceleration detection position is less than the height of the rising stop detection position. The dynamic height value is P2, where P2 = PjU + Smax - Sd, PjU is the reference value for ascent, Sd is the deceleration distance required for the spreader to slow down to a stop at the current speed, and Smax is the maximum deceleration distance of the spreader.

6. The rise control method as described in claim 5, characterized in that, The maximum deceleration distance of the spreader is calculated by the following formula: Smax = (1 / 2 Vmax) * Tmax; The deceleration distance required for the spreader to slow down to a stop from its current speed is calculated by the following formula: Sd = Vd * Vd * Tmax / (2Vmax); Vmax is the maximum speed of the hoisting mechanism, Tmax is the longest deceleration time of the hoisting mechanism, and Vd is the current speed of the spreader.

7. A lifting control system for a gantry crane hoisting mechanism, characterized in that, It includes a memory and a processor, wherein the memory stores a computer program that, when executed by the processor, implements the rise control method as described in any one of claims 5-6.

8. The lifting control system as described in claim 7, characterized in that, It also includes a height detection unit, a speed detection unit, a third position sensor, and a fourth position sensor, all of which are connected to the processor.

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