Active dynamic balance control method and system for tower crane

Abstract

The invention discloses an active dynamic balance control method and system for a tower crane, and the method comprises the steps: monitoring the vertical state of a tower body or the horizontal state of a working arm in real time, and obtaining an actual posture value; comparing the actual attitude value with a preset standard attitude value, and judging attitude deviation and direction; according to the deviation direction, a balance weight executing mechanism on the balance arm side is directly driven to act so as to change the balance torque, and the specific value of the needed torque is not calculated in advance in the adjusting process; and real-time monitoring is continuously carried out while adjustment is carried out until the attitude deviation is eliminated, and closed-loop control with the vertical tower body as a direct control target is formed. Through attitude feedback closed-loop control, any unbalance disturbance including inertia force can be sensed in real time and directly corrected, the tower body alternating bending moment is fundamentally eliminated, the foundation of tower body shaking is eradicated, the service life of a tower crane is remarkably prolonged, and meanwhile the structure of a control system is simplified.

Description

Technical Field

[0001] This invention relates to the field of tower crane automatic control technology, specifically to an active dynamic balance control method and system for tower cranes. Background Technology

[0002] Tower cranes are critical vertical and horizontal transportation equipment in construction engineering, and their working principle is based on torque balance. Currently, most existing tower cranes adopt a static balancing method, which involves pre-fixing counterweights at the end of the counterweight boom to balance the torque of the working boom under maximum load conditions. However, this static balancing method has inherent defects: in actual lifting operations, the torque of the working boom changes in real time with the lifting weight and the position of the luffing trolley, but the balancing torque remains constant. This causes the torque difference between the working boom and the counterweight boom to fluctuate continuously, which is converted into an alternating overturning moment and borne by the tower structure. As a result, the tower body is in a non-axial compression state for a long time, which not only causes tower swaying, affecting operational safety and operator comfort, but also accelerates fatigue damage to the metal structure of the standard tower sections, significantly shortening the service life of the equipment.

[0003] To address the aforementioned issues, various dynamic balancing solutions have been proposed in the industry. For example, CN116812768A discloses a control method based on a torque lookup table, which controls the motor output according to the lifting torque range corresponding to the position interval of the moving counterweight; CN115385246A determines the balance state and controls the moving counterweight by acquiring the unbalanced torque M in real time; CN115893234A uses a balance monitoring unit combined with mechanical analysis to pre-calculate the balance position for adjustment; and CN206407848U provides a counterweight movement signal by triggering a proximity switch when the balance plate tilts. However, the aforementioned existing technologies are all based on control logic of torque calculation or pre-analysis, which belong to the category of open-loop or feedforward control. Their common drawback is that they rely on components such as load cells and position sensors to perform complex torque modeling and calculation, and cannot sense and respond to dynamic inertial force disturbances generated by tower cranes under conditions such as sudden unloading, wind load, and centrifugal force of rotation. Any disturbance not covered by the model will lead to torque imbalance, and the method based on torque calculation cannot correct this in real time, and the tower body will still be subjected to alternating bending moments. Summary of the Invention

[0004] This invention proposes an active dynamic balancing control method and system for tower cranes. The "active dynamic balancing" mentioned in this invention means that the system takes the vertical state of the tower body as the direct control target, senses changes in the tower body's attitude in real time through attitude sensors, and actively drives the counterweight actuator to correct the deviation, forming a closed-loop feedback control. This enables real-time correction of various dynamic disturbances, including inertial forces. This differs from the open-loop or feedforward passive response control based on torque calculation in existing technologies. It solves the problem that existing tower cranes cannot sense and correct dynamic inertial force disturbances in real time due to metal fatigue caused by alternating bending moments in the tower body caused by static counterweights, which cannot be achieved through torque calculation methods.

[0005] The technical solution of this invention is implemented as follows:

[0006] A method for active dynamic balance control of a tower crane includes the following steps:

[0007] S1. Real-time monitoring steps: The vertical status of the tower body or the horizontal status of the boom of the tower crane is monitored in real time by attitude sensors to obtain the actual attitude value.

[0008] S2. Deviation judgment step: Compare the actual posture value with the preset standard posture value to determine whether there is a posture deviation and the direction of the deviation.

[0009] S3. Dynamic adjustment step: Based on the deviation direction, directly drive the counterweight actuator on the side of the balance arm to change the balance torque, and do not pre-calculate the specific value of the required balance torque during the adjustment process.

[0010] S4. Closed-loop feedback step: While driving the counterweight actuator, the real-time monitoring of step S1 is continuously performed until the deviation between the actual attitude value and the standard attitude value is eliminated, forming a closed-loop control with the tower body vertical or the working arm horizontal as the direct control target.

[0011] Furthermore, in step S2, multiple sets of attitude deviation ranges with different thresholds are preset, each corresponding to a different adjustment speed; when the actual attitude value falls into a certain deviation range, the counterweight actuator is controlled to respond and adjust at a speed corresponding to that range.

[0012] Furthermore, in step S3, the balancing torque is changed by altering the mass of the counterweight on the side of the balance arm; the counterweight is a liquid or the length of a coilable steel cable, and the mass of the counterweight on the side of the balance arm is changed by transferring the liquid or the length of the coiled steel cable.

[0013] Furthermore, in step S3, the balancing torque is changed by altering the lever arm length of the counterweight on the counterweight side; the counterweight is a pendulum, a counterweight trolley, or an openable counterweight lever arm, and the balancing torque is adjusted by changing its horizontal distance relative to the tower body or its equivalent lever arm length.

[0014] Furthermore, the counterweight is a pendulum, which is driven by a winch and a wire rope to swing along an arc-shaped trajectory; or the counterweight is a counterweight trolley, which is driven by a winch to move on guide rails that are relatively intersecting on the balance arm; or the counterweight is an openable counterweight arm, whose opening angle is changed by a gear motor.

[0015] Furthermore, the method also includes a non-working state adjustment step: when the tower crane is stopped and there is no load, the counterweight actuator is adjusted to keep the tower body vertical or the boom horizontal.

[0016] Furthermore, in step S3, the balancing torque is adjusted in a coordinated manner by simultaneously changing the mass of the counterweight and changing the lever arm length of the counterweight.

[0017] Furthermore, in step S1, the tilt angle of the tower or the horizontal angle of the working arm is monitored by tilt sensor, gyroscope or mercury tilt switch, and the angle is used as the actual attitude value.

[0018] A dynamic balance control system for a tower crane, comprising:

[0019] The attitude monitoring unit is installed on the tower body or the boom to monitor the vertical status of the tower crane or the horizontal status of the boom in real time and output the actual attitude value.

[0020] The control unit is electrically connected to the attitude monitoring unit and is used to receive the actual attitude value, compare it with the preset standard attitude value, determine the attitude deviation and direction, and generate control commands.

[0021] The counterweight actuator is located on the side of the balance arm and is electrically connected to the control unit. It is used to dynamically adjust the balance torque according to the control command.

[0022] Furthermore, the counterweight actuator includes one or more of the following: a liquid transfer device, a winch and steel cable combination device, a pendulum drive device, a counterweight trolley drive device, or a counterweight arm opening and closing drive device; the control unit is configured to execute the method described.

[0023] The beneficial effects of the technical solution provided in this application are as follows:

[0024] 1. This application proposes an active dynamic balance control method, the core of which is: by using real-time monitoring of the vertical state of the tower or the horizontal state of the boom as feedback signals, the actual attitude value is compared with the preset standard value to determine the direction of deviation, and the counterweight actuator on the side of the balance boom is directly driven to change the balance torque according to the direction of deviation, without pre-calculating the specific value of the required torque; while driving the counterweight actuator, real-time monitoring is continuously performed until the deviation between the actual attitude value and the standard value is eliminated, forming a closed-loop active control with the verticality of the tower as the direct control target. Compared with existing open-loop or feedforward control methods based on torque calculation (such as torque lookup table method, torque budget method, etc.), the existing methods belong to "passive balancing" - that is, the torque is calculated first and then adjusted. Essentially, it is a response to known loads and cannot sense and correct sudden dynamic disturbances. In contrast, this application takes "tower verticality" as the final control target and uses attitude sensors to replace the complex torque calculation model. It can actively sense any form of imbalance disturbance, including inertial force, and actively correct it in real time. This fundamentally eliminates the alternating bending moment borne by the tower body, significantly extends the service life of the tower crane, and simplifies the control system structure.

[0025] 2. This application achieves fine-tuning by presetting multiple sets of attitude deviation ranges with different thresholds and corresponding adjustment speeds such as slow, medium, and fast. This ensures smooth fine-tuning under small deviations and rapid response under large deviations, avoiding over-adjustment or response lag. By changing the counterweight mass through liquid transfer, steel cable winding length, etc., or by changing the lever arm length through pendulum, counterweight trolley, and openable counterweight lever arm, it provides a variety of flexible and reliable actuators to adapt to different tower crane models and working conditions. The cross-slope guide rail design enables vertical self-balancing of the counterweight trolley, reducing drive power consumption. By setting non-working state adjustment steps, it automatically adjusts to a balanced state when the tower crane is stopped and unloaded, effectively solving the safety hazard of the tower body bending and rotating towards the balance arm due to the fixed counterweight and causing funnel-shaped swaying in strong winds, further improving the tower crane's wind resistance and parking safety. By simultaneously using a combination of mass and lever arm adjustment methods, the adjustment range and response speed can be optimized synergistically, achieving more efficient dynamic balance. In addition, this application also provides a corresponding control system that organically combines the attitude monitoring unit, the control unit and various counterweight actuators to form a complete technical solution. Attached Figure Description

[0026] 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of a traditional tower crane.

[0028] Figure 2 This is a schematic diagram of the plumb bob scheme for the attitude monitoring device of the present invention;

[0029] Figure 3 This is a schematic diagram of the mercury tilt switch scheme for the attitude monitoring device of the present invention;

[0030] Figure 4 These are schematic diagrams of multiple designs for the mercury tilt switch scheme of the attitude monitoring device of the present invention;

[0031] Figure 5 This is a schematic diagram of Embodiment 1 of the present invention;

[0032] Figure 6 This is an enlarged schematic diagram of Embodiment 1 of the present invention;

[0033] Figure 7 This is a schematic diagram of Embodiment 2 of the present invention;

[0034] Figure 8 This is an enlarged schematic diagram of Scheme 1 of Embodiment 2 of the present invention;

[0035] Figure 9 This is an enlarged schematic diagram of Scheme 2 of Embodiment 2 of the present invention;

[0036] Figure 10 This is a schematic diagram of Embodiment 3 of the present invention;

[0037] Figure 11 This is a top-view enlarged schematic diagram of Embodiment 3 of the present invention;

[0038] Figure 12 This is a schematic diagram of Embodiment 4 of the present invention;

[0039] Figure 13 This is an enlarged schematic diagram of Embodiment 4 of the present invention;

[0040] Figure 14 This is a schematic diagram of Embodiment 5 of the present invention;

[0041] Figure 15 This is an enlarged schematic diagram of Embodiment 5 of the present invention;

[0042] Figure 16 This is a top-view enlarged schematic diagram of Embodiment 6 of the present invention;

[0043] Figure 17 This is a schematic diagram of the method flow of the present invention;

[0044] Figure 18 This is a schematic diagram of the system modules of the present invention. Detailed Implementation

[0045] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0046] This application uses real-time monitoring of the tower's vertical position or the boom's horizontal position as feedback signals. After comparing the actual attitude value with a standard value, it directly drives the counterweight actuator to adjust the balancing torque. The adjustment process does not pre-calculate the specific torque value and continuously monitors until the attitude deviation is eliminated, forming a closed-loop control with tower verticality as the direct control objective. Compared to existing open-loop or feedforward control methods based on torque calculation, this application abandons the complex torque modeling and calculation process. It directly uses attitude sensors to sense any form of imbalance disturbance and corrects it in real time until the tower is restored to verticality, thereby eliminating the alternating bending moment borne by the tower, significantly reducing metal fatigue, and significantly extending the tower crane's service life. Simultaneously, since it does not rely on load cells and complex torque calculation models, the control system structure is greatly simplified, resulting in faster response and higher reliability.

[0047] To more intuitively understand the technical concept of this invention, we can draw analogies using everyday examples. For instance, when carrying goods with a shoulder pole, people adjust the position of the pole on their shoulders or the weight of the goods in front and behind to keep the pole balanced and prevent it from tilting. Similarly, with a steelyard balance, the weight of the object is measured by moving the weight (changing the lever arm and thus the torque). When the balance beam is horizontal, it indicates torque balance. These two everyday examples reveal the essence of balance control: by sensing the balance state in real time (whether the shoulder pole or the balance beam is horizontal) and dynamically adjusting the force or lever arm, the system is always kept in a balanced position. This invention applies this simple principle to tower cranes, dynamically adjusting the torque on the balance arm side by monitoring the vertical state of the tower or the horizontal state of the boom in real time, thus achieving dynamic balance of the tower crane.

[0048] like Figures 17 to 18As shown, this invention provides an active dynamic balancing control method and system for tower cranes. The term "active dynamic balancing" as used here is in contrast to the "passive balancing" or "semi-active balancing" in existing technologies. In existing technologies, whether it's static counterweight or dynamic adjustment based on torque calculation (such as torque lookup table method or torque budget method), the essence is open-loop or feedforward control: the system needs to first obtain the load weight and position information, calculate the theoretically required balancing torque, and then drive the actuator to the predetermined position. This mode is essentially a "passive response" to a known load. Once an unmodeled disturbance occurs (such as sudden unloading, sudden wind load changes, slewing centrifugal force, etc.), the system cannot immediately sense and correct it, and the tower will still sway and bear alternating bending moments. In contrast, the "active dynamic balancing" of this invention takes the vertical state of the tower as the direct control target. It uses attitude sensors to sense the actual attitude of the tower in real time, treating any deviation from verticality as an imbalance signal and immediately driving the counterweight actuator to correct the deviation until the tower returns to verticality. This process requires no torque calculation, is unaffected by missing load information or model errors, and can proactively and in real-time respond to all forms of disturbances, truly achieving closed-loop active control of "monitoring-correction-balancing". The core concept of this method is: taking the verticality of the tower or the horizontality of the boom as the final control target, and achieving real-time tracking of the balancing torque to the working torque through closed-loop feedback control, thereby eliminating the alternating bending moment borne by the tower.

[0049] Specifically, the method of the present invention includes the following steps:

[0050] S1. Real-time monitoring step: The attitude sensor monitors the vertical state of the tower crane or the horizontal state of the boom in real time to obtain the actual attitude value.

[0051] S2, Deviation Judgment Step: Compare the actual attitude value with the preset standard attitude value to determine whether there is an attitude deviation and the direction of the deviation.

[0052] S3. Dynamic adjustment steps: Based on the direction of deviation, the counterweight actuator on the side of the balance arm is directly driven to change the balance torque, and the specific value of the required balance torque is not pre-calculated during the adjustment process.

[0053] S4. Closed-loop feedback step: While driving the counterweight actuator, the real-time monitoring step is continuously executed until the deviation between the actual attitude value and the standard attitude value is eliminated, forming a closed-loop control with the tower body vertical or the working arm horizontal as the direct control target.

[0054] The beneficial effects of the present invention have been described in detail in the preceding sections and will not be repeated here. The specific implementation methods of the present invention will be described in detail below with reference to several embodiments.

[0055] Basic Implementation of Closed-Loop Control Based on Attitude Monitoring

[0056] In this embodiment, a posture monitoring device first needs to be installed on the tower body or the boom. The posture monitoring device can be implemented in various forms. For example, Figure 2 A mechanical suspension system is illustrated, in which the suspended boom remains vertical under gravity. When the tower tilts, the boom contacts the surrounding curved metal plates. When the tower tilts forward and the suspended boom contacts curved metal plate 1, a low-voltage control circuit is activated, triggering a corresponding high-voltage relay. This, in turn, activates the circuit of the torque adjustment device, causing it to operate as specified, increasing the torque and correcting the tower's forward tilt. When the tower tilts backward and the suspended boom contacts curved metal plate 2, another low-voltage control circuit is activated, triggering another high-voltage relay. This causes the torque adjustment device to operate as specified, decreasing the torque and restoring the tower to verticality.

[0057] Figure 3 , 4 This paper illustrates a mercury tilt switch scheme for an attitude monitoring device. The mercury tilt switches are configured in three or more groups. In the first group, the two mercury tilt switches are positioned at a very small angle to the vertical plane, ensuring the mercury bulb remains in the open circuit. When the boom tilts slightly, the mercury bulb rolls, activating one of the microcircuits and sending a signal to the torque adjustment device, causing a slow increase or decrease in torque until the microcircuit disconnects. In the second group, the two mercury tilt switches are positioned at a medium angle to the vertical plane. When the boom tilts at a medium angle, the mercury bulb rolls, activating one of the microcircuits and sending a signal to the torque adjustment device, causing it to adjust at a medium speed. In the third group, the two mercury tilt switches are positioned at a larger angle to the vertical plane. When the boom tilts further, the mercury bulb rolls, activating one of the microcircuits and sending a signal to the torque adjustment device, causing it to adjust rapidly. The angle between each group of mercury tilt switches is calculated based on the specific tower crane model to ensure crane operation safety.

[0058] Mercury tilt switches are commercially available products; specific models can be substituted as needed. After adding a base and adjusting as required, they are ready for use. More preferably, the attitude monitoring device can directly detect the vertical state of the tower or the horizontal state of the boom using an electronic gyroscope or inclinometer. The inclinometer sends a signal to the control box, which then implements different control logic based on the signal. Using electronic sensors offers advantages such as high accuracy, fast response, and ease of integration.

[0059] Example 1: Pendulum Scheme

[0060] like Figure 5 As shown, this embodiment provides a pendulum scheme that adjusts the balancing torque by changing the lever arm length of the counterweight.

[0061] In terms of specific structure, the counterweight of the counterweight boom is changed to a pendulum form. When the tower crane is not in operation, the counterweight pendulum is brought as close to the tower body as possible. At this time, the torque generated by the pendulum is equal to the torque generated by the weight of the working boom and hook, so that the center of gravity of the tower crane is at the center of the tower body.

[0062] When the tower crane is operating at its maximum lifting capacity and the trolley is at its farthest point, the working torque is at its maximum. At this point, the counterweight pendulum is at the farthest point of the balance arm, and the torque generated is equal to the working torque, so that the center of gravity of the tower crane remains at the center of the tower body.

[0063] As the tower crane's traveling trolley moves along the boom and continuously changes the working torque, the winch, wire rope, and pulley system pull the pendulum to continuously change the angle of the pendulum, ensuring that the balancing torque is always equal to the working torque, thereby keeping the tower crane's center of gravity at the center of the tower body.

[0064] The torque balance control method is as follows: A level monitoring instrument is installed on the tower body, which controls the operation of the balance arm winch motor. When the boom is carrying a load or the traveling trolley moves to the far end, increasing the working torque, the boom tilts downwards and the tower body bends towards the boom side. The level monitoring instrument detects this posture change and controls the start of the balance arm winch motor, pulling the balance arm counterweight pendulum towards the tail end of the balance arm to increase the balancing torque until the tower body returns to vertical. When the boom traveling trolley moves towards the tower body, decreasing the working torque, the boom rises and the tower body bends towards the balance arm side. The level monitoring instrument controls the start of the balance arm winch motor, pulling the balance arm counterweight pendulum towards the tower body to decrease the balancing torque until the tower body returns to vertical. Figure 6 As shown.

[0065] This embodiment achieves dynamic adjustment of the balancing torque by changing the length of the counterweight arm through the arc-shaped motion of the pendulum. The pendulum scheme has a simple structure, a natural motion trajectory, and low drive power requirements, making it suitable for various types of tower cranes.

[0066] Example 2: Water Tank Solution

[0067] like Figure 7-9 As shown, this embodiment provides two water tank schemes, which adjust the balancing torque by changing the mass of the counterweight (water).

[0068] Option 1 (Pneumatic Driven): For example Figure 8As shown, a sealed pressure tank is installed and connected to an external air compressor to maintain the design pressure at all times. The air compressor automatically shuts down when the gas pressure in the pressure tank reaches the design pressure, and automatically starts to pressurize when the pressure is lower than the design pressure. When the tower crane is not in operation, the normally closed electric three-way valve 1 is activated to connect air pipes 1 and 3. Electric valve 3 is closed, and electric valve 2 is opened to push all the water into the water storage tank through the pressurized gas. Then, the electric shut-off valve on the water pipe is closed to center the tower crane's center of gravity. In operation, the electric shut-off valve on the water pipe is opened to allow the water pipe to flow.

[0069] When the tower crane is operating at its maximum lifting capacity and the trolley has traveled to its farthest point, and the working torque is at its maximum, the normally closed electric three-way valve 1 is activated to connect air pipe 1 and air pipe 2, the electric valve 2 is closed, and the electric valve 3 is opened. Pressurized gas is used to push water toward the balance tank. The torque generated by the weight of the water is equal to the working torque, so that the center of gravity of the tower crane is at the center of the tower body.

[0070] As the tower crane's traveling trolley continuously changes its working torque, the normally closed electric three-way valve 1 is activated to connect air passage 1 and air passage 2 or air passage 1 and air passage 3, allowing water to be distributed between the water storage tank and the balance tank, thereby adjusting the balance torque in real time to keep it equal to the working torque.

[0071] Option 2 (Pump-driven): For example Figure 9 As shown, a submersible pump and a float valve are installed in water storage tank 2. As long as there is water and the water level exceeds the minimum level, the submersible pump will continuously pump water to water storage tank 1. When the tower crane is not in operation, the electric shut-off valve 1 is closed and the electric shut-off valve 2 is opened, allowing all the water to flow into water storage tank 2. The submersible pump in the water storage tank will then automatically start and pump water to water storage tank 1.

[0072] When the tower crane is operating at its maximum lifting capacity and the trolley has traveled to its farthest point, and the working torque is at its maximum, close the electric shut-off valve 2 and open the electric shut-off valve 1 to allow water to flow into the balance tank. The torque generated by the weight of the water is equal to the working torque.

[0073] As the tower crane's traveling trolley continuously changes its working torque, by closing electric shut-off valve 1 and opening electric shut-off valve 2, or opening electric shut-off valve 1 and closing electric shut-off valve 2, potential energy is used to distribute water between water storage tank 1, water storage tank 2, and balance water tank, so that the balance torque is always equal to the working torque.

[0074] This embodiment provides a detailed analysis of the response time. According to Bernoulli's principle, the velocity of water in the connecting pipe is v = √2gh. Assuming a liquid level of 2.5 meters, the velocity is approximately 7 meters per second. Using a 400mm diameter connecting pipe, the time required to empty 10 cubic meters of water is approximately 11.37 seconds. Considering that each lifting process is not always at its limit (i.e., lifting and unloading at the maximum lifting width), the 11.37-second limit balancing torque time is sufficient for typical operational needs. To improve the response speed, the diameter of the connecting pipe or the number of connecting pipes can be increased.

[0075] The torque balance control method is as follows: A level monitoring device is installed on the tower body or the boom. For Scheme 1, the level monitoring device controls the operation of normally closed electric three-way valves 1, 2, and 3. When the boom is lifting a load or the traveling trolley moves to the far end, increasing the working torque, the boom tilts downward and the tower body bends towards the boom side. The level monitoring device controls the opening of the normally closed electric three-way valve, connecting air pipes 1 and 2, and closing electric valve 2, increasing the pressure of the water in the storage tank and pushing the water towards the balance tank, thus increasing the balancing torque. When the boom is unloading a load or the traveling trolley moves towards the tower body, decreasing the working torque, the boom rises and the tower body bends towards the balance boom side. The level monitoring device controls the opening of the normally closed electric three-way valve, connecting air pipes 1 and 3, and closing electric valve 3, increasing the pressure of the water in the balance tank and pushing the water towards the storage tank, thus decreasing the balancing torque.

[0076] For Scheme 2, the level monitoring instrument controls the operation of electric shut-off valves 1 and 2. When the boom is lifting a load or the traveling trolley moves to the far end, increasing the working torque, it controls the opening of electric shut-off valve 1 and the closing of electric shut-off valve 2, allowing the water to flow to the balance tank; when the boom is unloading a load or the traveling trolley moves towards the tower body, decreasing the working torque, it controls the closing of electric shut-off valve 1 and the opening of electric shut-off valve 2, allowing the water to flow to the storage tank 2.

[0077] The water tank solution uses water as a counterweight medium, which has the advantages of low cost, smooth adjustment, and stepless speed regulation, making it particularly suitable for occasions with high requirements for balance accuracy.

[0078] Example 3: Steel Cable Wrapping Solution

[0079] like Figure 10 , 11 As shown, this embodiment provides a winding steel cable scheme, which adjusts the balancing torque by changing the length of the steel cable involved in generating the torque (i.e., changing the effective counterweight mass).

[0080] In terms of specific structure, winch 1 and winch 2 are respectively installed at the tail of the counterweight boom and at the top of the tower. Winch 1 has a steel plate separating the middle of its drum, while winch 2 has two drums located on either side of the top of the tower. Two counterweight steel cables are wound around the corresponding drums of winch 1 and winch 2, and fixed pulleys and cable-supporting wheels are installed to guide the cable's direction. Figure 10 As shown. Additionally, a top-view schematic diagram of the winch is shown below. Figure 11 As shown.

[0081] When the tower crane is not in operation, the motor circuit of winch 2 is turned on, the drum of winch 2 rotates, and winch 1 rotates in turn, so that the counterweight steel cable is completely wound around the drum of winch 2. Since the axis of winch 2 coincides with the axis of the tower body, the counterweight steel cable does not generate torque on the tower body at this time.

[0082] When the tower crane is operating at its maximum lifting capacity and the luffing trolley is at its furthest point, and the working torque is at its maximum, the motor circuit of winch 1 is turned on, the drum of winch 1 rotates, and winch 2 rotates in turn, so that all the counterweight steel cable is wound around the drum of winch 1. The torque generated by the self-weight of the counterweight steel cable is equal to the working torque, so that the center of gravity of the tower crane is at the center of the tower body.

[0083] During tower crane lifting operations, as the luffing trolley continuously changes its working torque, the counterweight steel cable is wound and distributed on the drum of winch 1 or winch 2 by connecting the motor of winch 1 or winch 2, so that the balancing torque is always equal to the working torque in real time.

[0084] This embodiment analyzes the response time. Assuming there are two counterweight cables, each 8cm in diameter and 100 meters long, with a total mass of approximately 8 tons, roughly equivalent to existing tower crane counterweights, a linear velocity of 10 meters per second is required for the counterweight cables to completely switch between winch 1 and winch 2 in approximately 10 seconds. In practical applications, the number, diameter, length, and linear velocity of the counterweight cables can be adjusted according to the specific tower crane model and counterweight boom length to obtain the optimal configuration.

[0085] Counterweight steel cables can be made from multiple strands of scrapped or replaced lifting wire ropes. Since counterweight steel cables do not bear a large tensile force, it is only necessary to ensure their integrity. This can reduce costs and realize the utilization of scrapped wire ropes, which is environmentally friendly.

[0086] The torque balance control method is as follows: A level monitoring instrument is installed on the tower body or boom to control the operation of the motors of winch 1 and winch 2. When the boom is lifting a load or the traveling trolley moves to the far end, increasing the working torque, the boom tilts downward and the tower body bends towards the boom side. The level monitoring instrument controls the start of the winch 1 motor, causing the counterweight cable to wind onto the winch 1 drum, increasing the balancing torque. When the boom is unloading a load or the traveling trolley moves towards the tower body, decreasing the working torque, the boom rises upward and the tower body bends towards the counterweight boom side. The level monitoring instrument controls the start of the winch 2 motor, causing the counterweight cable to wind onto the winch 2 drum, decreasing the balancing torque.

[0087] The winding steel cable solution places the counterweight steel cable at the center of the tower, achieving zero torque output in non-working conditions. This effectively solves the balance problem in non-working conditions and also enables the reuse of waste steel cables, resulting in both economic and environmental benefits.

[0088] Example 4: Cross-slope sliding scheme

[0089] like Figure 12 , 13 As shown, this embodiment provides a sliding scheme on a cross-slope, which changes the horizontal projection distance of the counterweight trolley by moving it on the slope, thereby changing the lever arm length.

[0090] In terms of specific structure, two pairs of opposing, intersecting inclined guide rails are installed below the counterweight arm. A light steel truss is calculated and installed above the guide rails to ensure their bending resistance. A counterweight trolley is installed on the guide rails, and the trolley is connected to the guide rails via rolling friction pulleys. The trolley is connected to the winch cable, and a guide pulley is installed in the middle. Figure 13 As shown.

[0091] When the tower crane is not in operation, the hoist motor circuit is turned on to make it rotate clockwise. The counterweight trolley moves up and down and horizontally towards the tower body. At this time, the counterweight trolley generates a very small torque on the tower body.

[0092] When the tower crane is operating at its maximum lifting capacity and the luffing trolley has reached its farthest point, and the working torque is at its maximum, the winch motor circuit is turned on to make it rotate counterclockwise. The counterweight trolley moves up and down, and horizontally towards the tail end of the counterweight boom. The torque generated by the counterweight trolley's own weight is equal to the working torque.

[0093] During tower crane lifting operations, as the luffing trolley continuously changes its working torque, the winch motor is switched on to rotate clockwise or counterclockwise, causing the counterweight trolley to move on the inclined plane and change its horizontal projection distance, thereby adjusting the balance torque to ensure it is always equal to the working torque.

[0094] This embodiment analyzes the drive power and response time. Since the counterweight trolleys have equal mass, they are self-balancing during vertical movement. The winch does not require high power; it only needs to overcome the rolling friction between the counterweight trolleys and the guide rails. The winch mainly serves as a motion guide. Assuming each counterweight trolley weighs 2 tons, the total mass of the four trolleys is 8 tons, roughly equivalent to the counterweight blocks of existing tower cranes. When the counterweight trolleys move at a speed of 2 meters per second, it takes approximately 6 seconds for the trolleys to move from one end to the other. In practical applications, the optimal configuration can be obtained by adjusting the guide rail tilt angle, the mass of the counterweight trolleys, and the movement speed according to the specific tower crane model and the length of the counterweight boom.

[0095] The torque balance control method is as follows: A level monitoring device is installed on the tower body or boom to control the winch to operate clockwise or counterclockwise. When the boom is lifting a load or the traveling trolley moves to the far end, increasing the working torque, the boom tilts downwards and the tower body bends towards the boom side. The level monitoring device then controls the winch to rotate counterclockwise, causing the counterweight trolley to move towards the tail end of the balance boom, increasing the balancing torque. When the boom is unloading a load or the traveling trolley moves towards the tower body, decreasing the working torque, the boom rises and the tower body bends towards the balance boom side. The level monitoring device then controls the winch to rotate clockwise, causing the counterweight trolley to move towards the tower body, decreasing the balancing torque.

[0096] The cross-slope scheme utilizes the self-locking principle of the slope to achieve low-power driving of a large-mass counterweight, resulting in low energy consumption, fast response, and multiple counterweight trolleys that can be adjusted independently in pairs, providing flexible control.

[0097] Example 5: Pendulum and Winding Steel Cable Combination Scheme

[0098] like Figure 14 , 15 As shown, this embodiment provides a solution that combines a pendulum with a wound steel cable, while simultaneously changing the mass of the counterweight and the length of the lever arm to achieve coordinated adjustment.

[0099] In terms of specific structure, a counterweight pendulum is installed at the lower end of the counterweight arm. The pendulum is secured by a winch winding a counterweight steel cable. Figure 15 As shown.

[0100] When the tower crane is not in operation, the motor circuit of winch 2 is turned on, causing the drum of winch 2 to rotate. Winch 1 then rotates, causing all the counterweight cables to be wound around the drum of winch 2. Since the axis of winch 2 coincides with the axis of the tower body, the steel cables involved in the counterweight exert no torque on the tower body at this time. Simultaneously, the circuit of the pendulum winch is turned on, causing it to rotate clockwise and pull the pendulum counterweight to move in an arc to one side of the tower body.

[0101] When the tower crane is operating at its maximum lifting capacity and the luffing trolley is at its furthest point, with the working torque at its maximum, the motor circuit of winch 1 is activated. Winch 1's drum rotates, and winch 2 rotates subsequently, causing all the counterweight cables to be wound around the drum of winch 1. The torque generated by the weight of the counterweight cables is equal to the working torque. Simultaneously, the circuit of the pendulum winch is activated, causing it to rotate counterclockwise, pulling the counterweight pendulum in an arc towards the tail end of the counterweight boom.

[0102] The torque balance control method is as follows: A level monitoring instrument is installed on the tower body or boom to control the operation of winch 1, winch 2, and the pendulum winch. When the boom is lifting a load or the traveling trolley moves to the far end, increasing the working torque, the boom tilts downwards and the tower body bends towards the boom side. The level monitoring instrument controls the start of the winch 1 motor, causing the steel cable involved in the counterweight to wind onto the steel drum of winch 1, increasing the balancing torque; simultaneously, the pendulum winch pulls the pendulum in an arc towards the tail end of the counterweight boom. When the boom is unloading a load or the traveling trolley moves towards the tower body, reducing the working torque, the boom rises and the tower body bends towards the counterweight boom side. The level monitoring instrument controls the start of the winch 2 motor, causing the steel cable involved in the counterweight to wind onto the steel drum of winch 2, reducing the balancing torque; simultaneously, the pendulum winch pulls the pendulum in an arc towards the tower body side.

[0103] This embodiment changes the effective length of the steel cable involved in balancing by winding the steel cable and changes the lever arm length by swinging the pendulum. The two methods work together to quickly adjust the balancing torque over a wider range, making it particularly suitable for tower cranes with large tonnage or high-speed operation.

[0104] Example 6: Balancing Arm Opening and Closing Scheme

[0105] like Figure 16 As shown, this embodiment provides a balancing lever arm opening and closing scheme, which changes the equivalent lever arm length by changing the opening and closing angle of the counterweight lever arm.

[0106] In terms of specific structure, a counterweight mechanism that can be opened and closed is set on both sides of the balance arm. The opening and closing of the counterweight mechanism is used to change the size of the balance arm, thereby changing the balance torque.

[0107] When the tower crane is not in operation, the counterweight arm is fully extended, at which point the balancing torque is minimized.

[0108] When the tower crane is operating at its maximum lifting capacity and the luffing trolley is at its furthest point, and the working torque is at its maximum, the balance arm is brought together on both sides of the balance arm to increase the balancing torque and balance the working torque.

[0109] The torque balance control method is as follows: A level monitoring device is installed on the tower body or boom. A gear is installed at the root of the balance arm, meshing with a gear motor. The rotation of the gear motor controls the opening and closing of the balance arm. When the boom is lifting a load or the traveling trolley moves to the far end, increasing the working torque, the boom tilts downwards and the tower body bends towards the boom side. The level monitoring device controls the gear motor circuit to activate, causing the symmetrical balance arms to rotate and retract at both ends of the balance arm, increasing the balancing torque. When the boom is unloading a load or the traveling trolley moves towards the tower body, decreasing the working torque, the boom rises and the tower body bends towards the balance arm side. The level monitoring device controls the gear motor circuit to activate, causing the symmetrical balance arms to rotate and open on both sides of the balance arm, decreasing the balancing torque.

[0110] The opening and closing lever arm scheme has a compact structure, and the lever arm can be continuously adjusted through a simple opening and closing action. The two lever arms are symmetrically arranged, which naturally cancels out the lateral torque and the force is evenly distributed, making it suitable for space-constrained occasions.

[0111] Although the above embodiments differ in their implementation methods, they all follow the same core inventive concept: using the verticality of the tower or the horizontality of the boom as the direct control target, and achieving real-time tracking of the working torque by the balancing torque through closed-loop feedback control. Those skilled in the art can choose one or more combinations of these embodiments based on actual working conditions and cost considerations.

[0112] Since the maximum sway of the tower body occurs at the top, and the maximum vertical sway of the boom occurs at the end of the boom furthest from the tower body, and the tower crane's operator's cab is almost at the top of the tower, the level monitoring device can be placed in the crane operator's cab or at the very end of the boom. Because tower crane installation requires the tower body to be vertical and not exceed the deviation limit, and correspondingly requires the boom to be horizontal and not exceed the deviation limit, the level monitoring device only needs to monitor the verticality of the tower body or the horizontality of the boom.

[0113] This invention also provides a dynamic balancing control system for tower cranes, used to execute the aforementioned dynamic balancing control method. The system mainly comprises three components: an attitude monitoring unit, a control unit, and a counterweight actuator.

[0114] The attitude monitoring unit is installed on the tower body or boom of the tower crane to monitor the vertical status of the tower body or the horizontal status of the boom in real time and output the actual attitude value. The attitude monitoring unit can be implemented in various forms, including but not limited to: mechanical hammer devices, mercury tilt switches, electronic gyroscopes, or tilt sensors. The output of the attitude monitoring unit is electrically connected to the control unit, transmitting the real-time acquired attitude signals to the control unit.

[0115] The control unit is the core processing component of the system, typically implemented using a programmable logic controller (PLC), embedded processor, or industrial control computer. The control unit is electrically connected to the attitude monitoring unit, receiving actual attitude values, comparing them with preset standard attitude values, determining the existence and direction of attitude deviation, and generating corresponding control commands based on the deviation direction. The control unit has pre-set control logic that can execute the aforementioned dynamic balance control method of this invention, including advanced functions such as multi-level response speed control and automatic adjustment in non-working states. The output of the control unit is electrically connected to the counterweight actuator, transmitting control commands to the actuator.

[0116] The counterweight actuator is located on the side of the counterweight arm and is electrically connected to the control unit. It is used to dynamically adjust the balancing torque according to control commands. Depending on the implementation method, the counterweight actuator can come in various forms: liquid transfer device, winch and cable combination device, pendulum drive device, counterweight trolley drive device, counterweight arm opening and closing drive device, etc. These actuators can be used individually or in combination as needed.

[0117] The system's workflow is as follows: The attitude monitoring unit senses the vertical state of the tower or the horizontal state of the boom in real time and sends the actual attitude value to the control unit; the control unit compares the actual attitude value with the preset standard attitude value to determine if there is a deviation and its direction; based on the direction of the deviation, the control unit generates a corresponding control command and sends it to the counterweight actuator; the counterweight actuator responds to the control command and changes the balancing torque; while the counterweight actuator is operating, the attitude monitoring unit continues to monitor in real time and feeds back the updated attitude value to the control unit; the control unit determines whether the attitude deviation has been eliminated based on the feedback signal; if not, it continues to adjust until the tower is restored to vertical or the boom is restored to horizontal, forming a complete closed-loop feedback control. The system's control logic can be preset with multiple modes according to actual needs, such as using different response speeds (slow, medium, and fast) based on the magnitude of the attitude deviation, or automatically adjusting to a balanced state when the tower crane is stopped and unloaded.

[0118] Through the above system architecture, this invention realizes automated and intelligent control of active dynamic balancing of tower cranes, effectively solves the problem of alternating bending moment caused by traditional static counterweights, significantly extends the service life of tower cranes, and improves operational safety.

[0119] It is worth mentioning that the counterweight in this invention can preferably be composed of standardized, modular cast iron parts, for example, each part weighing 50 kg. This standardized design has multiple advantages: First, different tower crane models can flexibly combine cast iron parts of the same specifications according to the required total counterweight mass, achieving the universality and interchangeability of the counterweight blocks, eliminating the need to customize concrete counterweight blocks for each tower crane, significantly reducing manufacturing and inventory costs; Second, the cast iron parts can be reused for a long time. Even if the tower crane is scrapped, the counterweight blocks can still be recycled for use in other equipment, avoiding the environmental pollution problems caused by the difficult disposal of broken traditional concrete counterweight blocks, which is in line with the concepts of green manufacturing and sustainable development; Third, the standardized parts are easy to install, disassemble, and transport, improving construction efficiency. Therefore, this invention not only achieves innovation in control methods but also fully considers economy and environmental protection in the specific implementation of the counterweight actuator.

[0120] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for active dynamic balance control of a tower crane, characterized in that, Includes the following steps: S1. Real-time monitoring steps: The vertical status of the tower body or the horizontal status of the boom of the tower crane is monitored in real time by attitude sensors to obtain the actual attitude value. S2. Deviation judgment step: Compare the actual posture value with the preset standard posture value to determine whether there is a posture deviation and the direction of the deviation. S3. Dynamic adjustment step: Based on the deviation direction, directly drive the counterweight actuator on the side of the balance arm to change the balance torque, and do not pre-calculate the specific value of the required balance torque during the adjustment process. S4. Closed-loop feedback step: While driving the counterweight actuator, the real-time monitoring of step S1 is continuously performed until the deviation between the actual attitude value and the standard attitude value is eliminated, forming a closed-loop control with the tower body vertical or the working arm horizontal as the direct control target.

2. The method according to claim 1, characterized in that, In step S2, multiple sets of attitude deviation ranges with different thresholds are preset, each corresponding to a different adjustment speed; when the actual attitude value falls into a certain deviation range, the counterweight actuator is controlled to respond and adjust at a speed corresponding to that range.

3. The method according to claim 1, characterized in that, In step S3, the balancing torque is changed by altering the mass of the counterweight on the side of the balance arm; the counterweight is a liquid or the length of a coilable steel cable, and the mass of the counterweight on the side of the balance arm is changed by transferring the liquid or the length of the coiled steel cable.

4. The method according to claim 1, characterized in that, In step S3, the balancing torque is changed by altering the lever arm length of the counterweight on the counterweight side; the counterweight is a pendulum, a counterweight trolley, or an openable counterweight lever arm, and the balancing torque is adjusted by changing its horizontal distance relative to the tower body or its equivalent lever arm length.

5. The method according to claim 4, characterized in that, The counterweight is a pendulum, which is driven by a winch and a wire rope to swing along an arc-shaped trajectory; or the counterweight is a counterweight trolley, which is driven by a winch to move on guide rails that are relatively intersecting on the balance arm; or the counterweight is an openable counterweight arm, whose opening angle is changed by a gear motor.

6. The method according to claim 1, characterized in that, The method also includes a non-working state adjustment step: when the tower crane is stopped and there is no load, the counterweight actuator is adjusted to keep the tower body vertical or the boom horizontal.

7. The method according to claim 1, characterized in that, In step S3, the balance torque is adjusted by simultaneously changing both the mass of the counterweight and the length of the lever arm of the counterweight.

8. The method according to any one of claims 1 to 7, characterized in that, In step S1, the tilt angle of the tower or the horizontal angle of the working arm is monitored by tilt sensor, gyroscope or mercury tilt switch, and the angle is used as the actual attitude value.

9. A dynamic balance control system for a tower crane, characterized in that, include: The attitude monitoring unit is installed on the tower body or the boom to monitor the vertical status of the tower crane or the horizontal status of the boom in real time and output the actual attitude value. The control unit is electrically connected to the attitude monitoring unit and is used to receive the actual attitude value, compare it with the preset standard attitude value, determine the attitude deviation and direction, and generate control commands. The counterweight actuator is located on the side of the balance arm and is electrically connected to the control unit. It is used to dynamically adjust the balance torque according to the control command.

10. The system according to claim 9, characterized in that, The counterweight actuator includes one or more of the following: a liquid transfer device, a winch and cable combination device, a pendulum drive device, a counterweight trolley drive device, or a counterweight arm opening and closing drive device; the control unit is configured to perform the method as described in any one of claims 1 to 7.

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