A method, system, device and program product for controlling the posture of a sling

Abstract

The present invention provides a method, system, device and program product for controlling the posture of a sling, wherein a plurality of motors are arranged above the sling, and each of the motors is connected to the sling via a steel wire rope, and the method comprises: obtaining the current posture of the sling and the preset final posture of the sling; estimating the predicted torque value applied to the sling in a future preset time period based on the current posture of the sling and the final posture of the sling based on the MPC algorithm; determining the output torque value of each of the motors in a future preset time period based on the predicted torque value; and controlling the operation of the corresponding motors based on the output torque value of each of the motors to change the posture of the sling. The sling posture control method of the present invention can improve the adjustment speed of the sling, reduce overshoot, and enable the sling to reach a given position quickly and stably.

Description

Technical Field

[0001] The present invention relates to the field of crane technology, and in particular to a method, system, device and program product for controlling the position and posture of a sling. Background Art

[0002] Active anti-sway crane is a new type of crane structure. Compared with the traditional eight-rope rail crane, it has the advantages of light weight, simple structure, and long wire rope life. Therefore, it has been widely used in the field of port cranes in recent years. However, the active anti-sway crane uses anti-sway wire rope to adjust the position of the spreader. Compared with the traditional eight-rope telescopic rod spreader position adjustment method, its control speed of the spreader position is slow and the accuracy is low. Therefore, how to better control the spreader posture through the anti-sway wire rope of the active anti-sway crane has also become a research hotspot in recent years.

[0003] At present, the control algorithm for the posture of active anti-sway crane hoisting equipment is the Proportional Integration Differentiation (PID) control algorithm. However, the PID control algorithm has the following shortcomings in practical applications: PID-based control requires on-site testing to determine the optimal parameter values, which takes a lot of time, has a slow adjustment speed and poor control accuracy; the PID control algorithm has a large overshoot, and the control system takes a long time to reach a steady state, resulting in poor control effect.

[0004] Therefore, a method for controlling the posture of an active anti-sway crane spreader with fast adjustment speed, small overshoot and high control accuracy is needed. Summary of the invention

[0005] In view of the above-mentioned problems in the prior art, an object of the present invention is to provide a method, system, device and program product for controlling the posture of a sling, which can improve the adjustment speed of the sling and reduce overshoot.

[0006] In order to solve the above problems, the present invention provides a method for controlling the position and posture of a sling, wherein a plurality of motors are arranged above the sling, and each of the motors is connected to the sling via a steel wire rope. The method comprises:

[0007] Obtaining a current spreader posture and a preset spreader final posture of the spreader;

[0008] Based on the MPC algorithm, a predicted torque value applied to the spreader within a future preset time period is estimated according to the current spreader posture and the final spreader posture;

[0009] Determine the output torque value of each of the motors within a future preset time period according to the predicted torque value;

[0010] The operation of the corresponding motors is controlled according to the output torque values ​​of the motors respectively, so as to change the posture of the sling.

[0011] Furthermore, the current sling posture and the final sling posture both include postures in the front-to-back direction, left-to-right direction, and rotational direction; the predicted torque value includes the predicted torque value applied to the sling in the front-to-back direction, left-to-right direction, and rotational direction.

[0012] Furthermore, the estimating the predicted torque value applied to the spreader within a preset time period in the future based on the MPC algorithm according to the current spreader posture and the final spreader posture includes:

[0013] Calculate the posture offset and offset speed in each direction according to the current posture of the spreader and the final posture of the spreader;

[0014] respectively determining the current torque value applied to the spreader in each direction;

[0015] For each direction, according to the posture offset, offset speed and current torque value in the direction, based on the preset state space model, the optimal torque value applied to the spreader in the direction within a future preset time period is predicted as the predicted torque value in the direction.

[0016] Further, determining the output torque value of each of the motors within a future preset time period according to the predicted torque value includes:

[0017] Performing different addition and subtraction arrangements on the predicted torque values ​​applied to the spreader in various directions to form a plurality of intermediate variables, wherein the number of the intermediate variables is equal to the number of the motors;

[0018] Adding a preset offset to each of the intermediate variables;

[0019] The respective intermediate variables after adding the preset offset are output with upper and lower amplitude limits respectively, so as to obtain the output torque value of each motor.

[0020] Another aspect of the present invention provides a sling posture control system, wherein a plurality of motors are arranged above the sling, each of the motors is connected to the sling via a wire rope, and the system comprises: an MPC controller and an MPC mixer, wherein the output of the MPC controller is connected to the input of the MPC mixer;

[0021] The MPC controller is used to obtain the current spreader posture and the preset final spreader posture of the spreader; based on the MPC algorithm, estimate the predicted torque value applied to the spreader within a preset time period in the future according to the current spreader posture and the final spreader posture;

[0022] The MPC mixer is used to determine the output torque value of each of the motors within a future preset time period according to the predicted torque value; and control the operation of the corresponding motor according to the output torque value of each of the motors to change the posture of the hoist.

[0023] Furthermore, the current sling posture and the final sling posture both include postures in the front-to-back direction, left-to-right direction, and rotational direction; the predicted torque value includes the predicted torque value applied to the sling in the front-to-back direction, left-to-right direction, and rotational direction.

[0024] Further, the MPC controller is set to three, corresponding to the front-to-back direction, the left-to-right direction and the rotation direction respectively;

[0025] The MPC controllers corresponding to each direction are respectively used to obtain the current sling posture and the final sling posture in the corresponding direction; calculate the posture offset and offset speed in the corresponding direction according to the current sling posture and the final sling posture in the corresponding direction; determine the current torque value applied to the sling in the corresponding direction; and predict the optimal torque value applied to the sling in the corresponding direction within a preset time period in the future based on a preset state space model according to the posture offset, offset speed and current torque value in the corresponding direction, as the predicted torque value in the corresponding direction.

[0026] Further, the MPC mixer comprises:

[0027] an arrangement unit, used for performing different addition and subtraction arrangements on the predicted torque values ​​applied to the spreader in various directions to form a plurality of intermediate variables, wherein the number of the intermediate variables is equal to the number of the motors;

[0028] An increment unit, used to add a preset offset to each of the intermediate variables;

[0029] The output unit is used to output each intermediate variable after adding a preset offset, and to obtain the output torque value of each motor.

[0030] Another aspect of the present invention provides a sling posture control device for controlling the posture of the sling, wherein the sling posture control device comprises the sling posture control system as described above.

[0031] Another aspect of the present invention provides a computer program product, comprising a computer program / instruction, which implements the steps of the above-mentioned method for controlling the posture of the sling when executed by a processor.

[0032] Due to the above technical solution, the present invention has the following beneficial effects:

[0033] According to the sling posture control method of an embodiment of the present invention, based on the MPC algorithm, the current sling posture of the sling and the preset final sling posture are used to continuously predict the optimal torque value applied to the sling within a preset time period in the future, and then determine the output torque value of each motor, and control the motor operation according to the output torque value, which can improve the adjustment accuracy and adjustment speed of the sling, reduce overshoot, and enable the sling to reach a given position quickly and stably. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments or prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 is a schematic diagram of a lifting device of an active anti-sway crane provided by an embodiment of the present invention;

[0036] Figure 2 It is a schematic diagram of the circuit structure of a sling posture control system provided by one embodiment of the present invention;

[0037] Figure 3 is a flow chart of a method for controlling a sling posture provided by an embodiment of the present invention;

[0038] Figure 4 is a schematic diagram of the circuit structure of an MPC mixer provided by one embodiment of the present invention;

[0039] Figure 5 It is a schematic diagram of an overshoot waveform of a traditional PID control system provided by an embodiment of the present invention;

[0040] Figure 6 It is a schematic diagram of an overshoot waveform of a sling posture control system provided by an embodiment of the present invention.

[0041] Reference numerals: 10. Motor, 20. Wire rope, 30. Spreader, 40. MPC controller, 50. MPC mixer. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, device, product or equipment that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0044] In order to make the objectives, technical solutions and advantages disclosed in the embodiments of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and embodiments.

[0045] Reference Manual Attached Figure 1 , which shows a schematic diagram of a lifting device of an active anti-sway crane provided by an embodiment of the present invention, such as Figure 1 As shown, a plurality of motors 10 are arranged above the spreader 30 of the active anti-sway crane, each motor 10 is connected to the spreader 30 via a steel wire rope 20, and each motor 10 is used to adjust the posture of the spreader 30. Specifically, the number of motors 10 can be set to 4, each motor 10 is connected to 4 right-angle positions of the spreader 30 via a steel wire rope 20, wherein the motor 10 can be an anti-sway motor, and the steel wire rope 20 can be an anti-sway steel wire rope.

[0046] In the embodiment of the present invention, the posture of the sling 30 can be controlled and adjusted by the sling posture control system based on the sling position control method provided in the embodiment of the present invention. Figure 2 As shown, the hanger posture control system may include a model predictive control (MPC) controller 40 and an MPC mixer 50, and the output of the MPC controller 40 is connected to the input of the MPC mixer 50. Specifically, the number of the MPC controllers 40 may be set to three, and the inputs of the three MPC controllers 40 are respectively connected to the front-to-back direction error, left-to-right direction error, and rotation direction error of the hanger 30 (i.e., the difference between the final hanger posture given and the current hanger posture feedback), and the outputs of the three MPC controllers 40 are connected to the MPC mixer 50, and the output of the MPC mixer 50 is the torque of the four motors 10, and the torque of the motor 10 is transmitted to the hanger 30 through the wire rope 20, so as to change the position of the hanger 30 in the front-to-back direction, left-to-right direction, and rotation direction.

[0047] Reference Manual Attached Figure 3, which shows the process of a method for controlling the position and posture of a sling provided by an embodiment of the present invention, which can be applied to Figure 2 In the hanger posture control system, it is used to control Figure 1 The position of the sling in the . Figure 3 As shown, the method may include the following steps:

[0048] S310: Acquire the current spreader posture and the preset spreader final posture of the spreader.

[0049] In an embodiment of the present invention, the final posture of the sling may be a predetermined final posture to which the sling is to be adjusted, and the current posture of the sling may be posture feedback of the sling. Specifically, the current posture of the sling and the final posture of the sling both include postures in the front-to-back direction, the left-to-right direction, and the rotational direction.

[0050] In actual engineering applications, the final posture of the spreader in the front-to-back direction, left-to-right direction, and rotational direction will have a clear given position. For example, the business personnel can input it into the spreader posture control system according to the actual situation as the input of the MPC controller.

[0051] S320: Based on the MPC algorithm, estimate the predicted torque value applied to the spreader within a future preset time period according to the current spreader posture and the spreader final posture.

[0052] In an embodiment of the present invention, the MPC controller can use the current sling posture and the final sling posture to predict the optimal torque value applied to the sling in the front-to-back direction, the left-to-right direction, and the rotational direction within a future preset time period based on a preset state space model as a predicted torque value. Specifically, the predicted torque value may include the predicted torque value applied to the sling in the front-to-back direction, the left-to-right direction, and the rotational direction. The duration of the future preset time period can be set according to actual needs, and the embodiment of the present invention does not limit this.

[0053] Specifically, the estimating the predicted torque value applied to the spreader within a future preset time period based on the current spreader posture and the spreader final posture based on the MPC algorithm may include:

[0054] Calculate the posture offset and offset speed in each direction according to the current posture of the spreader and the final posture of the spreader;

[0055] respectively determining the current torque value applied to the spreader in each direction;

[0056] For each direction, according to the posture offset, offset speed and current torque value in the direction, based on the preset state space model, the optimal torque value applied to the spreader in the direction within a future preset time period is predicted as the predicted torque value in the direction.

[0057] Among them, the preset state space model can be a state space model of a predetermined active anti-sway crane, the posture offset and offset speed in each direction include the posture offset and offset speed in the front and rear direction, the left and right direction, and the rotation direction, and the future preset time can be set according to actual conditions, and the embodiment of the present invention is not limited to this.

[0058] Specifically, the MPC controller can use the MPC algorithm, based on the state space model of the active anti-sway crane, to take the posture offset and offset speed in each direction, and the current torque value of the motor as input, and predict the change of the sling posture caused by different motor torque output values ​​in the future N sampling time periods, and determine the optimal torque value of the motor in the corresponding direction in the future N sampling time periods by optimizing the control algorithm (quadratic programming). At this time, the optimal torque value in the next sampling time period can be used as the predicted torque value in the corresponding direction, that is, the duration of the future preset time period can be set to the duration of a sampling time period. Among them, the value of N and the duration of the sampling time period can be set according to actual conditions, and the embodiment of the present invention does not limit this.

[0059] The embodiment of the present invention uses the MPC algorithm to predict the optimal torque value of the motor in each direction within a future preset time period, and then determines the actual torque value of each motor. The torque output value of each motor can be accurately determined without on-site testing, thereby improving the adjustment accuracy and adjustment speed of the spreader.

[0060] In actual engineering applications, the MPC controller can be set to three, each MPC controller is used to predict the predicted torque value applied to the spreader in one direction. The MPC controller is mainly composed of the state space model of the active anti-sway crane and the MPC controller output constraints.

[0061] For the convenience of modeling, the embodiment of the present invention controls the three directions of the z-axis (trolley direction), x-axis (truck direction) and skew axis (rotation direction) of the sling respectively. The control quantity is the torque of the motor. Changes in different motor torques will cause different changes in the posture of the sling in the three directions.

[0062] Specifically, the state space equation of the active anti-sway crane is as follows, which is used to obtain the state vector at the next sampling time based on the current state vector and the input:

[0063] X i+1 =AXi +Bu i +C

[0064] Among them, X is the state vector (the difference between the final position and posture of the spreader in three directions and the current position feedback of the spreader), A, B, and C will be given in the subsequent state space equation derivation process, and the state vector X in the next N sampling time periods is:

[0065] X i+2 =AX i+1 +Bu i+1 +C=A 2 X i +ABu i +Bu i+1 +AC+C

[0066] X i+3 =AX i+2 +Bu i+2 +C=A 3 X i +A 2 Bu i +ABu i+1 +Bu i+2 +A 2 C+AC+C

[0067] By analogy, we can get the following equation:

[0068]

[0069] Right now

[0070]

[0071] The optimal input vector u (optimal torque value of the motor) within the next N sampling time periods can be calculated by the quadratic programming algorithm. It should be noted that the specific calculation method is a prior art and will not be described in detail in the embodiments of the present invention.

[0072] Among them, the derivation process of the state space equation of the active anti-sway crane is as follows:

[0073]

[0074]

[0075]

[0076]

[0077] Among them, m is the weight of the spreader and the load, x is the displacement of the spreader in the front-to-back direction, u is the output torque of the motor, L is the distance between the center of the trolley frame and the motor in the front-to-back direction of the spreader, and H is the height of the spreader from the center of the trolley frame. From this, the state space equation can be obtained as:

[0078]

[0079] Right now

[0080]

[0081] From this, we can get the values ​​of A, B, and C in the state space equation.

[0082] S330: Determine the output torque value of each of the motors within a future preset time period according to the predicted torque value.

[0083] In an embodiment of the present invention, the MPC controller can output the predicted torque value applied to the sling in the front-to-back direction, left-to-right direction and rotational direction within a preset time period in the future to the MPC mixer, and the MPC mixer can integrate the predicted torque values ​​in the three directions and convert them into the actual output torque value of the motor.

[0084] Specifically, determining the output torque value of each of the motors within a future preset time period according to the predicted torque value may include:

[0085] Performing different addition and subtraction arrangements on the predicted torque values ​​applied to the spreader in various directions to form a plurality of intermediate variables, wherein the number of the intermediate variables is equal to the number of the motors;

[0086] Adding a preset offset to each of the intermediate variables;

[0087] The respective intermediate variables after adding the preset offset are output with upper and lower amplitude limits respectively, so as to obtain the output torque value of each motor.

[0088] In actual engineering applications, refer to the attached manual. Figure 4 The input of the MPC mixer is the output of the three MPC controllers. Different addition and subtraction arrangements of these three inputs can form four intermediate variables (for example, intermediate variable No. 1 is input No. 1 minus input No. 2 plus input No. 3, intermediate variable No. 2 is input No. 1 plus input No. 2 minus input No. 3, intermediate variable No. 3 is negative input No. 1 minus input No. 2 minus input No. 3, intermediate variable No. 4 is negative input No. 1 plus input No. 2 plus input No. 3), and then an offset is added to each intermediate variable, and then the upper and lower amplitude limits are applied to the output, and the output is the torque of the four motors.

[0089] The embodiment of the present invention performs addition and subtraction on the predicted motor torque values ​​in three directions output by the MPC controller to integrate them into the final actual motor output torque value. By adding a bias, it is possible to prevent the wire rope from being loose, and to perform upper and lower amplitude limit output to prevent the wire rope from being too tight or too loose, thereby ensuring that the motor can adjust the position of the sling through the wire rope.

[0090] S340: Controlling the operation of the corresponding motors according to the output torque values ​​of the motors respectively to change the posture of the lifting device.

[0091] In an embodiment of the present invention, the MPC controller may output the output torque value of each of the motors to the corresponding motor, so that each motor outputs according to the corresponding output torque value within a future preset time period to change the posture of the sling.

[0092] In actual engineering applications, at the end of the next sampling time period (future preset time period), the above steps S310 to S340 can be repeated, and the above optimization process can be repeated through the latest data to determine the optimal torque output value of the motor in the next sampling time period. The above optimization process is continuously repeated until the sling posture reaches the given sling final posture.

[0093] In conjunction with the reference manual Figure 5 and Figure 6 , under the same given input, the overshoot of the traditional PID control system is 23.6%, the overshoot of the MPC control system is 4%, and the overshoot of the MPC control system is reduced by 83.05%; the stabilization time of the traditional PID control system is 8.5s, the stabilization time of the MPC control system is 0.56s, and the stabilization time of the MPC control system is accelerated by 93.41%. It can be seen that the sling posture control method provided by the embodiment of the present invention has a shorter stabilization time and a smaller overshoot than the traditional PID control method.

[0094] In summary, according to the sling posture control method of an embodiment of the present invention, based on the MPC algorithm, the current sling posture of the sling and the preset final sling posture are used to continuously predict the optimal torque value applied to the sling within a preset time period in the future, and then determine the output torque value of each motor, and control the motor operation according to the output torque value, which can improve the adjustment accuracy and adjustment speed of the sling, reduce overshoot, and shorten the system stabilization time, so that the sling can reach a given position quickly and stably.

[0095] An embodiment of the present invention further provides a sling posture control system, which can be used to control and adjust the posture of the sling, wherein a plurality of motors are arranged above the sling, and each of the motors is connected to the sling via a wire rope. Specifically, the sling posture control system can include an MPC controller and an MPC mixer, wherein the output of the MPC controller is connected to the input of the MPC mixer.

[0096] Among them, the MPC controller can be used to obtain the current sling posture and the preset final sling posture of the sling; based on the MPC algorithm, the predicted torque value applied to the sling in a future preset time period is estimated according to the current sling posture and the final sling posture; the MPC mixer can be used to determine the output torque value of each of the motors in a future preset time period according to the predicted torque value; and the operation of the corresponding motors is controlled according to the output torque value of each of the motors to change the posture of the sling.

[0097] In an embodiment of the present invention, the current sling posture and the final sling posture may both include postures in the front-to-back direction, left-to-right direction, and rotational direction; the predicted torque value may include the predicted torque value applied to the sling in the front-to-back direction, left-to-right direction, and rotational direction.

[0098] In a possible embodiment, the MPC controller can be set to three, corresponding to the front-to-back direction, the left-to-right direction and the rotation direction respectively; the MPC controllers corresponding to each direction are respectively used to obtain the current sling posture and the final sling posture of the corresponding direction; the posture offset and offset speed of the corresponding direction are calculated according to the current sling posture and the final sling posture of the corresponding direction; the current torque value applied to the sling in the corresponding direction is determined; according to the posture offset, offset speed and current torque value of the corresponding direction, the optimal torque value applied to the sling in the corresponding direction within a preset time period in the future is predicted based on a preset state space model as the predicted torque value in the corresponding direction.

[0099] In a possible embodiment, the MPC mixer may include: an arrangement unit, used to perform different addition and subtraction arrangements on the predicted torque values ​​applied to the sling in various directions to form a plurality of intermediate variables, and the number of the intermediate variables is equal to the number of the motors; an increment unit, used to add a preset offset to each of the intermediate variables; and an output unit, used to perform upper and lower limit output on each intermediate variable after adding the preset offset, so as to obtain the output torque value of each motor.

[0100] An embodiment of the present invention further provides a sling posture control device for controlling and adjusting the posture of a sling, wherein the sling posture control device includes the sling posture control system provided in the above-mentioned various optional embodiments.

[0101] One embodiment of the present invention also provides a computer-readable storage medium, which can be set in a sling posture control device to store at least one instruction or at least one program related to implementing a sling posture control method. When the at least one instruction or the at least one program is loaded and executed by the processor, the steps of the sling posture control method provided in the above-mentioned various optional embodiments are implemented.

[0102] Optionally, in an embodiment of the present invention, the above-mentioned storage medium may include but is not limited to: a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk, and other media that can store program codes.

[0103] One embodiment of the present invention also provides a computer program product, including a computer program / instruction, which is stored in a computer-readable storage medium. When the computer program / instruction is executed by a processor, the steps of the sling posture control method provided in the above-mentioned various optional embodiments are implemented.

[0104] It should be noted that the sequence of the embodiments of the present invention described above is for description only and does not represent the advantages and disadvantages of the embodiments. The above describes specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0105] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0106] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0107] 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling the position and posture of a sling, wherein a plurality of motors are arranged above the sling, and each of the motors is connected to the sling via a steel wire rope, characterized in that: The method comprises: Obtaining a current spreader posture and a preset spreader final posture of the spreader; Based on the MPC algorithm, a predicted torque value applied to the spreader within a future preset time period is estimated according to the current spreader posture and the final spreader posture; Determine the output torque value of each of the motors within a future preset time period according to the predicted torque value; Controlling the operation of the corresponding motors according to the output torque values ​​of the motors to change the posture of the sling; Wherein, the current spreader posture and the final spreader posture both include postures in the front-to-back direction, the left-to-right direction, and the rotational direction; the predicted torque value includes the predicted torque value applied to the spreader in the front-to-back direction, the left-to-right direction, and the rotational direction; The method of estimating the predicted torque value applied to the spreader within a preset time period in the future based on the current spreader posture and the spreader final posture based on the MPC algorithm includes: Calculate the posture offset and offset speed in each direction according to the current posture of the spreader and the final posture of the spreader; respectively determining the current torque value applied to the spreader in each direction; For each direction, according to the posture offset, offset speed and current torque value in the direction, based on a preset state space model, predict an optimal torque value applied to the spreader in the direction within a future preset time period as the predicted torque value in the direction; Determining the output torque value of each of the motors within a future preset time period according to the predicted torque value includes: Performing different addition and subtraction arrangements on the predicted torque values ​​applied to the spreader in various directions to form a plurality of intermediate variables, wherein the number of the intermediate variables is equal to the number of the motors; Adding a preset offset to each of the intermediate variables; The respective intermediate variables after adding the preset offset are output with upper and lower amplitude limits respectively, so as to obtain the output torque value of each motor.

2. A sling posture control system, wherein a plurality of motors are arranged above the sling, and each of the motors is connected to the sling via a steel wire rope, characterized in that: The system comprises: an MPC controller and an MPC mixer, wherein the output of the MPC controller is connected to the input of the MPC mixer; The MPC controller is used to obtain the current spreader posture and the preset final spreader posture of the spreader; based on the MPC algorithm, estimate the predicted torque value applied to the spreader within a preset time period in the future according to the current spreader posture and the final spreader posture; The MPC mixer is used to determine the output torque value of each of the motors within a future preset time period according to the predicted torque value; and control the operation of the corresponding motors according to the output torque value of each of the motors to change the posture of the spreader; The current spreader posture and the final spreader posture both include postures in the front-to-back direction, the left-to-right direction, and the rotational direction; the predicted torque value includes the predicted torque value applied to the spreader in the front-to-back direction, the left-to-right direction, and the rotational direction; The MPC controllers are set to three, corresponding to the front-to-back direction, the left-to-right direction, and the rotation direction respectively; The MPC controllers corresponding to each direction are respectively used to obtain the current spreader posture and the final spreader posture of the corresponding direction; calculate the posture offset and offset speed of the corresponding direction according to the current spreader posture and the final spreader posture of the corresponding direction; determine the current torque value applied to the spreader in the corresponding direction; and predict the optimal torque value applied to the spreader in the corresponding direction within a preset time period in the future based on a preset state space model according to the posture offset, offset speed and current torque value of the corresponding direction, as the predicted torque value in the corresponding direction; The MPC mixer comprises: an arrangement unit, used for performing different addition and subtraction arrangements on the predicted torque values ​​applied to the spreader in various directions to form a plurality of intermediate variables, wherein the number of the intermediate variables is equal to the number of the motors; An increment unit, used to add a preset offset to each of the intermediate variables; The output unit is used to output each intermediate variable after adding a preset offset, and to obtain the output torque value of each motor.

3. A sling posture control device, used to control the posture of the sling, characterized in that: The sling posture control device includes the sling posture control system as claimed in claim 2.

4. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the method for controlling the posture of the sling as claimed in claim 1 are implemented.

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