Tower crane and its counterbalance control method and counterbalance control system

Abstract

The application relates to the field of engineering machinery and discloses a tower crane, a balance control method and a balance control system thereof. The tower crane comprises a hoisting device, a moving balance weight and a buffer device arranged on the hoisting device. The buffer device is used for prolonging the time of the hoisting device in the process of lifting a heavy object off the ground and landing. The balance control method comprises the following steps: in the process of lifting a heavy object off the ground or landing, the real-time unbalanced moment M of the tower crane is acquired in real time; whether the balance of the tower crane is in an abnormal state is judged according to the real-time unbalanced moment M; when the balance of the tower crane is in the abnormal state, the lifting action of the hoisting device is limited, and the moving balance weight is controlled to move along a balance arm until the balance of the tower crane is restored to a normal state and is static. The application can solve the balance problem caused by the sharp change of the unbalanced moment of the tower body in the process of lifting a heavy object off the ground and landing.

Description

Technical Field

[0001] This invention belongs to the field of engineering machinery, specifically relating to a balance control method for a tower crane, a balance control system for a tower crane, and a tower crane itself. Background Technology

[0002] In existing tower cranes, the balance control system controls the movement of the counterweight during the horizontal movement of the lifting device while the load is being lifted, thereby keeping the unbalanced torque within a reasonable range and achieving the purpose of balancing the tower crane. However, the balance control system can only solve the balance problem during the horizontal movement of the lifting device while the load is being lifted. It cannot solve the balance problem caused by the rapid changes in the unbalanced torque on the tower crane during the lifting process when the load is lifted off the ground and then lowered to the ground. Summary of the Invention

[0003] In view of the above-mentioned deficiencies or defects in the prior art, the present invention provides a balance control method for a tower crane, a balance control system for a tower crane, and a tower crane, aiming to solve the balance problem caused by the rapid change of unbalanced torque on the tower body during the two processes of lifting a load off the ground and lowering it to the ground.

[0004] To achieve the above objectives, the present invention provides a balance control method for a tower crane. The tower crane includes a lifting jib, a counterweight jib, a lifting device, and a movable counterweight. The movable counterweight is movably mounted on the counterweight jib, and the lifting device is mounted on the lifting jib. The tower crane further includes a buffer device mounted on the lifting device, the buffer device being used to extend the time of the lifting device lifting the load off the ground and the time of the load landing. The balance control method includes:

[0005] During the process of lifting heavy objects off the ground or lowering them to the ground by the lifting device, the real-time unbalanced torque M of the tower crane is acquired in real time.

[0006] The balance of the tower crane is determined based on the real-time unbalanced torque M.

[0007] When the tower crane is in an abnormal state of balance, the lifting action of the lifting device is restricted, and the moving counterweight is controlled to move along the counterweight arm until the tower crane is restored to a normal state and then stops.

[0008] Optionally, determining whether the tower crane's balance is in an abnormal state based on the real-time unbalanced torque M includes:

[0009] Judge whether the absolute value |M| of the real-time unbalance torque M and the allowable unbalance torque M1 satisfy the relationship: |M|≥M1; if so, the balance of the tower crane is in an abnormal state.

[0010] Optionally, when the balance of the tower crane is in an abnormal state, restricting the hoisting operation of the hoisting device and controlling the moving counterweight to move along the balance arm until the balance of the tower crane is in a normal state and then stop, including:

[0011] During the process of the hoisting device hoisting a heavy object off the ground, when the balance of the tower crane is in an abnormal state, restricting the hoisting action of the hoisting device and controlling the moving counterweight to move along the balance arm in a direction away from the tower body of the tower crane until the balance of the tower crane is in a normal state and then stop.

[0012] Optionally, when the balance of the tower crane is in an abnormal state, restricting the hoisting operation of the hoisting device and controlling the moving counterweight to move along the balance arm until the balance of the tower crane is in a normal state and then stop, including:

[0013] During the process of the hoisting device lowering a heavy object to the ground, when the balance of the tower crane is in an abnormal state, restricting the lowering action of the hoisting device and controlling the moving counterweight to move along the balance arm in a direction close to the tower body of the tower crane until the balance of the tower crane is in a normal state and then stop.

[0014] Optionally, controlling the moving counterweight to move along the balance arm until the balance of the tower crane is restored to a normal state and then stop, including:

[0015] During the movement of the moving counterweight, judge whether the real-time unbalance torque M and the allowable unbalance torque M1 satisfy the relationship: -M1≤M<M; if so, the balance of the tower crane is restored to a normal state.

[0016] Optionally, the balance control method further includes:

[0017] After the balance of the tower crane is restored to a normal state, cancel the restriction on the hoisting operation of the hoisting device, and control the hoisting device to continue hoisting a heavy object off the ground or lowering it to the ground.

[0018] The present invention also provides a balance control system for a tower crane, the tower crane including a lifting jib, a counterweight jib, a lifting device, and a movable counterweight, the movable counterweight being movably mounted on the counterweight jib, the lifting device being mounted on the lifting jib, and the tower crane further including a buffer device mounted on the lifting device, the buffer device being used to extend the time of the lifting device lifting the load off the ground and the time of the lifting device landing the load on the ground, the balance control system including:

[0019] The unbalanced torque detection module is used to acquire the real-time unbalanced torque M of the tower crane during the lifting process of the hoisting device lifting the load off the ground or lowering it to the ground; and

[0020] The control module is configured as follows:

[0021] The balance of the tower crane is determined based on the real-time unbalanced torque M.

[0022] When the tower crane is in an abnormal balance, the lifting action of the lifting device is restricted, and the moving counterweight is controlled to move along the counterweight arm until the tower crane is in a normal balance and then stops.

[0023] Optionally, the control module is further configured to:

[0024] Determine whether the absolute value of the real-time unbalanced torque M, |M|, satisfies the relationship with the allowable unbalanced torque M1: |M|≥M1; if so, the tower crane is in an abnormal balance state.

[0025] Optionally, the control module is further configured to:

[0026] During the lifting process of the lifting device lifting the load off the ground, if the tower crane is in an abnormal state of balance, the lifting action of the lifting device is restricted, and the moving counterweight is controlled to move along the counterweight arm in a direction away from the tower body of the tower crane until the tower crane is in a normal state of balance and then stops.

[0027] Optionally, the control module is further configured to:

[0028] During the process of lowering the load to the ground by the lifting device, if the tower crane is in an abnormal state of balance, the lowering action of the lifting device is restricted, and the moving counterweight is controlled to move along the counterweight arm toward the tower body of the tower crane until the tower crane is in a normal state of balance and then stops.

[0029] Optionally, the control module is further configured to:

[0030] During the movement of the mobile counterweight, it is judged whether the real-time unbalanced torque M and the allowable unbalanced torque M1 satisfy the relationship: -M1 ≤ M < M1; if so, the balance of the tower crane is restored to the normal state.

[0031] Optionally, the control module is further configured to:

[0032] After the balance of the tower crane is restored to the normal state, the restriction on the hoisting action of the hoisting device is cancelled, and the hoisting device is controlled to continue hoisting or lowering the heavy object to leave or land on the ground.

[0033] The present invention also provides a tower crane, including the above-mentioned balance control system.

[0034] Through the above technical solutions, during the process of the hoisting device hoisting or lowering the heavy object to leave or land on the ground, the buffer device can extend the time of the process of the hoisting device hoisting the heavy object off the ground and the process of landing, thereby avoiding the problem that the movement adjustment of the mobile counterweight is seriously lagged due to the sudden change of the unbalanced torque during the process of the heavy object leaving or landing on the ground. Then, by obtaining the real-time unbalanced torque M, when it is judged that the balance of the tower crane is in an abnormal state according to the real-time unbalanced torque M, the hoisting action of the hoisting device is restricted and the mobile counterweight is moved to restore the balance of the tower crane to the normal state. In this way, the balance problem caused by the sharp change of the unbalanced torque on the tower body during the two processes of the hoisting device hoisting the heavy object off the ground and lowering it to land on the ground can be solved, so that the tower body of the tower crane remains in a better balance state during the two processes of the heavy object hoisting off the ground and lowering it to land on the ground, ensuring the reliability of the hoisting work.

[0035] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation part. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. Together with the following specific implementation manners, they are used to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:

[0037] Figure 1 is a flowchart of the balance control method of the tower crane in an embodiment of the present invention;

[0038] Figure 2 is a schematic structural diagram of the tower crane in an embodiment of the present invention.

[0039] Description of the reference numerals:

[0040] 1 Boom 4 Mobile counterweight

[0041] 2 Balance arm 5 Buffer device

[0042] 3. Lifting device Detailed Implementation

[0043] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0045] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used to describe the relative positions of components in relation to the directions shown in the accompanying drawings or in relation to the vertical, perpendicular, or gravitational directions.

[0046] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0047] This invention first provides a method for balancing control of a tower crane.

[0048] In one implementation, refer to the appendix. Figure 1 and attached Figure 2 As shown, the tower crane includes a lifting boom 1, a counterweight boom 2, a lifting device 3, and a movable counterweight 4. The movable counterweight 4 is movably mounted on the counterweight boom 2. The lifting device 3 is mounted on the lifting boom 1. The tower crane also includes a buffer device 5 mounted on the lifting device 3. The buffer device 5 is used to extend the time during the lifting process of the load leaving the ground and landing. The balance control method includes:

[0049] During the process of lifting heavy objects off the ground or lowering them to the ground by the lifting device 3, the real-time unbalanced torque M of the tower crane is obtained in real time.

[0050] Determine whether the tower crane is in an abnormal balance state based on the real-time unbalanced torque M.

[0051] When the tower crane is in an abnormal state of balance, the lifting device 3 is restricted from lifting, and the moving counterweight 4 is controlled to move along the counterweight arm 2 until the tower crane is restored to a normal state and then stops.

[0052] It should be noted that the process of lifting the load off the ground by the lifting device 3 is the process of the load gradually lifting off the ground under the lifting force of the lifting device 3 (during this process, the ground also provides support for the load) until it is completely off the ground; the process of lowering the load to the ground by the lifting device 3 is the process of gradually lowering the load to the ground (during this process, the ground begins to provide support for the load) until it is completely on the ground (at this time, the load is completely supported by the ground).

[0053] In this embodiment, the real-time unbalanced torque M is calculated based on the real-time torques generated by the weight of the moving counterweight, the self-weight of the counterweight arm, the self-weight of the crane arm, the weight of the load, and the wind load. Specifically, the real-time unbalanced torque M is obtained by subtracting the sum of the real-time torques generated by the weight of the moving counterweight and the self-weight of the counterweight arm from the sum of the real-time torques generated by the self-weight of the crane arm, the weight of the load, and the wind load.

[0054] In this embodiment, specifically, refer to the appendix. Figure 2 As shown, the lifting device 3 includes a luffing trolley, a wire rope luffing mechanism, and a hook mounted on the boom 1. The buffer device includes a cylinder, a pressure plate, and a compression spring. The pressure plate is located inside the cylinder to divide the inner cavity of the cylinder into an upper cavity and a lower cavity. The compression spring is located inside the lower cavity and is compressed by the pressure plate and the bottom wall of the lower cavity. The top of the hook passes through the bottom wall of the lower cavity and is fixedly connected to the pressure plate. The top of the cylinder is connected to the luffing trolley via a wire rope. The luffing mechanism can raise and lower the buffer device and the hook synchronously by winding and unwinding the wire rope. The luffing trolley can drive the buffer device and the hook to move horizontally synchronously. When the hook lifts the load off the ground or lands on the ground, the compression spring acts as a buffer, which can prolong the time of lifting the load off the ground and landing on the ground.

[0055] Understandably, during the lifting process of the hoisting device 3 lifting the load off the ground or lowering it to the ground, the buffer device 5 can extend the time of the lifting process and the landing process of the load. This avoids the problem of serious lag in the movement adjustment of the moving counterweight 4 caused by sudden changes in the unbalanced torque during the lifting or landing process. Then, by acquiring the real-time unbalanced torque M, when it is determined that the tower crane is in an abnormal balance state based on the real-time unbalanced torque M, the lifting action of the hoisting device 3 is restricted and the moving counterweight 4 is moved to restore the balance of the tower crane to a normal state. In this way, the balance problem caused by the rapid change in the unbalanced torque on the tower body during the lifting and landing processes of the load by the hoisting device 3 can be solved, so that the tower body of the tower crane can maintain a better balance state during the lifting and landing processes, ensuring the reliability of the lifting operation.

[0056] In one implementation, determining whether the tower crane's balance is in an abnormal state based on the real-time unbalanced torque M includes:

[0057] Determine whether the absolute value of the real-time unbalanced moment M, |M|, satisfies the relationship with the allowable unbalanced moment M1: |M|≥M1; if so, the tower crane is in an abnormal balance state.

[0058] In one embodiment, when the tower crane is in an abnormal balance state, the lifting device 3 is restricted in its lifting action, and the moving counterweight 4 is controlled to move along the counterweight arm 2 until the tower crane's balance is restored to a normal state and then comes to a stop, including:

[0059] During the lifting process of the lifting device 3 lifting the load off the ground, if the tower crane is in an abnormal state of balance, the lifting action of the lifting device 3 is restricted, and the moving counterweight 4 is controlled to move along the counterweight arm 2 in a direction away from the tower body of the tower crane until the tower crane is in a normal state of balance and then stops.

[0060] Specifically, restricting the lifting action of the lifting device 3 means stopping the lifting device 3 from lifting the heavy object upwards or controlling the lifting device 3 to lower downwards.

[0061] Understandably, during the process of lifting the load off the ground by the lifting device 3, the torque generated by the weight of the load gradually increases. By controlling the moving counterweight 4 to move along the counterweight arm 2 in a direction away from the tower body of the tower crane, the real-time unbalanced torque M can be effectively reduced, so that the value of the real-time unbalanced torque M is reduced to within the allowable range, thereby keeping the tower crane in a normal balance.

[0062] Furthermore, it can be determined that the lifting device 3 is in the process of lifting the load off the ground by judging that the real-time unbalanced torque M is greater than 0. That is, when the balance of the tower crane is in an abnormal state, it can be determined whether the real-time unbalanced torque M is greater than 0. If so, the lifting device 3 is in the process of lifting the load off the ground.

[0063] In one embodiment, when the tower crane is in an abnormal balance state, the lifting device 3 is restricted in its lifting action, and the moving counterweight 4 is controlled to move along the counterweight arm 2 until the tower crane's balance is restored to a normal state and then comes to a stop, including:

[0064] During the process of lowering the load to the ground by the lifting device 3, if the tower crane is in an abnormal state of balance, the lowering action of the lifting device 3 is restricted, and the moving counterweight 4 is controlled to move along the counterweight arm 2 toward the tower body of the tower crane until the tower crane is in a normal state of balance and then stops.

[0065] Specifically, restricting the lowering action of the lifting device 3 means stopping the lifting device 3 from lowering the heavy object or controlling the lifting device 3 to lift upward.

[0066] Understandably, during the process of lowering the heavy load by the hoisting device 3 until it touches the ground, the moment generated by the weight of the heavy load gradually decreases. By controlling the moving counterweight 4 to move along the balance arm 2 towards the tower body of the tower crane, the real-time unbalanced moment M can be effectively reduced, and the numerical value of the real-time unbalanced moment M can be reduced to within the allowable range, thereby keeping the balance of the tower crane in a normal state.

[0067] Furthermore, it can be judged that the hoisting device 3 is in the process of lowering the heavy load until it touches the ground by judging that the real-time unbalanced moment M is less than 0. That is, when the balance of the tower crane is in an abnormal state, it is judged whether the real-time unbalanced moment M is less than 0. If so, the hoisting device 3 is in the process of lowering the heavy load until it touches the ground.

[0068] In one embodiment, controlling the moving counterweight 4 to move along the balance arm 2 until the balance of the tower crane is restored to the normal state and then stops, includes:

[0069] During the movement of the moving counterweight 4, it is judged whether the real-time unbalanced moment M and the allowable unbalanced moment M1 satisfy the relationship: -M1 ≤ M < M1; if so, the balance of the tower crane is restored to the normal state.

[0070] In one embodiment, the balance control method further includes:

[0071] After the balance of the tower crane is restored to the normal state, the restriction on the hoisting action of the hoisting device 3 is cancelled, and the hoisting device 3 is controlled to continue hoisting the heavy load to lift off the ground or lower it to the ground. With such a setting, during the process of the hoisting device 3 hoisting the heavy load to lift off the ground and lower it to the ground, the balance of the tower crane can be kept in a normal state.

[0072] In one embodiment, the balance control method further includes:

[0073] During the process of the hoisting device 3 horizontally moving the heavy load, the real-time unbalanced moment M is obtained in real time;

[0074] It is judged whether the absolute value |M| of the real-time unbalanced moment M and the allowable unbalanced moment M1 satisfy the relationship: |M| ≥ M1; if so, the balance of the tower crane is in an abnormal state;

[0075] When the balance of the tower crane is in an abnormal state, the hoisting device 3 is stopped from moving or moved in the direction where the absolute value |M| decreases, and the moving counterweight 4 is controlled to move along the balance arm 2 in the direction where the absolute value |M| decreases. During the movement of the moving counterweight 4, it is judged whether the real-time unbalanced moment M and the allowable unbalanced moment M1 satisfy the relationship: -M1 ≤ M < M1; if so, the moving counterweight 4 is controlled to stop, and the hoisting device 3 is controlled to continue moving in the original direction.

[0076] In this way, the tower crane can maintain its balance in a normal state during the horizontal movement of the load carried by the lifting device, and continuously and reliably achieve the operation of moving the load.

[0077] The present invention also provides a balance control system for a tower crane. The tower crane includes a lifting jib 1, a counterweight 2, a lifting device 3, and a movable counterweight 4. The movable counterweight 4 is movably mounted on the counterweight 2. The lifting device 3 is mounted on the lifting jib 1. The tower crane also includes a buffer device 5 mounted on the lifting device 3. The buffer device 5 is used to extend the time of the lifting device 3 during the lifting process of the load leaving the ground and during the landing process. The balance control system includes:

[0078] The unbalanced torque detection module is used to acquire the real-time unbalanced torque M of the tower crane during the lifting process of the hoisting device 3, which lifts the loaded load off the ground or lowers it back to the ground; and

[0079] The control module is configured as follows:

[0080] Determine whether the tower crane is in an abnormal balance state based on the real-time unbalanced torque M.

[0081] When the tower crane is in an abnormal state of balance, the lifting device 3 is restricted from lifting, and the moving counterweight 4 is controlled to move along the counterweight arm 2 until the tower crane is restored to a normal state and then stops.

[0082] Understandably, the unbalanced torque detection module is connected to the control module. When the lifting device 3 lifts the load off the ground or lowers it to the ground, the unbalanced torque detection module detects and calculates the real-time unbalanced torque M of the tower crane and sends it to the control module. The control module receives the real-time unbalanced torque M and controls the movement of the moving counterweight 4 according to the real-time unbalanced torque M, so that the tower crane maintains a normal balance.

[0083] In one implementation, the control module is further configured to:

[0084] Determine whether the absolute value of the real-time unbalanced moment M, |M|, satisfies the relationship with the allowable unbalanced moment M1: |M|≥M1; if so, the tower crane is in an abnormal balance state.

[0085] In one implementation, the control module is further configured to:

[0086] During the lifting process of the lifting device 3 lifting the load off the ground, if the tower crane is in an abnormal state of balance, the lifting action of the lifting device 3 is restricted, and the moving counterweight 4 is controlled to move along the counterweight arm 2 in a direction away from the tower body of the tower crane until the tower crane is in a normal state of balance and then stops.

[0087] In one embodiment, the control module is further configured to:

[0088] During the process of the lifting device 3 lowering the lifted heavy object to the ground, when the balance of the tower crane is in an abnormal state, the lowering action of the lifting device 3 is restricted, and the moving counterweight 4 is controlled to move along the balance arm 2 towards the direction close to the tower body of the tower crane until the balance of the tower crane returns to the normal state and then stops.

[0089] In one embodiment, the control module is further configured to:

[0090] During the movement of the moving counterweight 4, it is judged whether the real-time unbalanced torque M and the allowable unbalanced torque M1 satisfy the relationship: -M1 ≤ M < M1; if so, the balance of the tower crane is restored to the normal state.

[0091] In one embodiment, the control module is further configured to:

[0092] After the balance of the tower crane is restored to the normal state, the restriction on the lifting action of the lifting device 3 is cancelled, and the lifting device 3 is controlled to continue to lift the heavy object off the ground or lower it to the ground.

[0093] The present invention also provides a tower crane, the above-mentioned balance control system.

[0094] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0095] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, they can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0096] In addition, any combination can be made between various different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A method for balancing a tower crane, the tower crane comprising a jib (1), a counterweight (2), a lifting device (3), and a movable counterweight (4), the movable counterweight (4) being movably mounted on the counterweight (2), and the lifting device (3) being mounted on the jib (1), characterized in that, The tower crane also includes a buffer device (5) installed on the lifting device (3), the buffer device (5) being used to extend the time of the lifting device (3) lifting the load off the ground and landing the load on the ground. The balance control method includes: During the process of lifting heavy objects off the ground or lowering them to the ground by the lifting device (3), the real-time unbalanced torque M of the tower crane is obtained in real time. Determining whether the tower crane is in an abnormal balance state based on the real-time unbalanced torque M includes: determining whether the absolute value of the real-time unbalanced torque M, |M|, satisfies the relationship with the allowable unbalanced torque M1: |M|≥M1; if so, the tower crane is in an abnormal balance state. When the tower crane is in an abnormal state of balance, the lifting device (3) is restricted from lifting, and the moving counterweight (4) is controlled to move along the counterweight arm (2) until the tower crane is restored to a normal state and then stops. During the process of lifting the load off the ground by the lifting device (3), when the balance of the tower crane is in an abnormal state, the lifting action of the lifting device (3) is restricted, and the moving counterweight (4) is controlled to move along the counterweight arm (2) in a direction away from the tower body of the tower crane until the balance of the tower crane is in a normal state and then stops; and / or, during the process of lowering the load to the ground by the lifting device (3), when the balance of the tower crane is in an abnormal state, the lowering action of the lifting device (3) is restricted, and the moving counterweight (4) is controlled to move along the counterweight arm (2) in a direction close to the tower body of the tower crane until the balance of the tower crane is in a normal state and then stops.

2. The balance control method according to claim 1, characterized in that, The control of the moving counterweight (4) to move along the counterweight arm (2) until the tower crane returns to its normal balance and comes to rest includes: During the movement of the moving counterweight (4), it is determined whether the real-time unbalanced torque M and the allowable unbalanced torque M1 satisfy the relationship: -M1≤M< M1; if so, the balance of the tower crane is restored to normal.

3. The balance control method according to claim 1, characterized in that, Balance control methods also include: After the tower crane is restored to its normal balance, the restriction on the lifting action of the lifting device (3) is lifted, and the lifting device (3) is controlled to continue lifting heavy objects off the ground or lowering them to the ground.

4. A balance control system for a tower crane, the tower crane comprising a lifting boom (1), a counterweight boom (2), a lifting device (3), and a movable counterweight (4), the movable counterweight (4) being movably mounted on the counterweight boom (2), and the lifting device (3) being mounted on the lifting boom (1), characterized in that, The tower crane also includes a buffer device (5) installed on the lifting device (3), the buffer device (5) being used to extend the time of the lifting device (3) lifting the load off the ground and landing the load. The balance control system includes: The unbalanced torque detection module is used to acquire the real-time unbalanced torque M of the tower crane during the lifting process of the lifting device (3) lifting the load off the ground or lowering it to the ground; and The control module is configured as follows: Determining whether the tower crane is in an abnormal balance state based on the real-time unbalanced torque M includes: determining whether the absolute value of the real-time unbalanced torque M, |M|, satisfies the relationship with the allowable unbalanced torque M1: |M|≥M1; if so, the tower crane is in an abnormal balance state. When the tower crane is in an abnormal state of balance, the lifting device (3) is restricted from lifting, and the moving counterweight (4) is controlled to move along the counterweight arm (2) until the tower crane is in a normal state of balance and then stops. During the process of lifting the load off the ground by the lifting device (3), if the balance of the tower crane is in an abnormal state, the lifting action of the lifting device (3) is restricted, and the moving counterweight (4) is controlled to move along the counterweight arm (2) in a direction away from the tower body of the tower crane until the balance of the tower crane is in a normal state and then stops; and / or, during the process of lowering the load to the ground by the lifting device (3), if the balance of the tower crane is in an abnormal state, the lowering action of the lifting device (3) is restricted, and the moving counterweight (4) is controlled to move along the counterweight arm (2) in a direction close to the tower body of the tower crane until the balance of the tower crane is in a normal state and then stops.

5. The balance control system according to claim 4, characterized in that, The control module is further configured as follows: During the movement of the moving counterweight (4), it is determined whether the real-time unbalanced torque M and the allowable unbalanced torque M1 satisfy the relationship: -M1≤M< M1; If so, then the tower crane is in a normal balance.

6. The balance control system according to claim 4, characterized in that, The control module is further configured as follows: After the tower crane is restored to its normal balance, the restriction on the lifting action of the lifting device (3) is lifted, and the lifting device (3) is controlled to continue lifting heavy objects off the ground or lowering them to the ground.

7. A tower crane, characterized in that, Includes the balance control system according to any one of claims 4 to 6.

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