Method for operating a crane

Abstract

Embodiments of this disclosure relate to a method for operating a crane. A computer-implemented method for operating a crane includes the following steps: generating speed data of a drive unit of the crane such that oscillations of the crane are suppressed (S100); providing a compatibility model configured to describe the relationship between input speed reference data of the crane's drive unit and output position reference data of the crane's drive unit (S110); determining position reference data of the crane's drive unit by inputting the speed reference data into the compatibility model (S120); providing the position reference data of the crane's drive unit to a control of the crane's drive unit, and controlling the crane's drive unit according to the position reference data (S130).

Description

Technical Field

[0001] The present invention relates to a computer-implemented method for operating a crane, an apparatus for operating a crane, a system, and a computer program product configured to perform the steps of the method. Background Technology

[0002] Cranes are widely used to move goods in warehouses, factories, or ports. Cranes are well-known in the prior art. Cranes can be operated manually or automatically. Goods moved by cranes move like loads and can oscillate. This can be a challenge in moving goods.

[0003] It is now clear that there is also a need to provide the possibility of operating the crane. Summary of the Invention

[0004] In view of the above, one object of the present invention is to provide a method for operating a crane, and more specifically, one object of the present invention is to provide an improved method for operating a crane.

[0005] In one aspect of this disclosure, a computer-implemented method for operating a crane is provided, the method comprising the following steps:

[0006] The speed reference data of the crane's drive unit is generated, thereby suppressing the crane's oscillations;

[0007] A compatibility model is provided, which is configured to describe the relationship between the input speed reference data of the crane's drive unit and the output position reference data of the crane's drive unit;

[0008] The position reference data of the crane's drive unit is determined by inputting the speed reference data into the compatibility model;

[0009] The method provides position reference data of the crane's drive unit to the controls of the crane's drive unit, and controls the crane's drive unit based on the position data. This method advantageously provides the drive unit with a position control mode and an anti-sway control mode, wherein the position control mode and the anti-sway control mode are compatible with each other. Optionally, determining the position reference data of the crane's drive unit may also include inputting preliminary position data.

[0010] In an embodiment of the method, the controls for the crane's drive unit may include controls in the position loop, such as a proportional controller.

[0011] In an embodiment of the method, the controls for the crane's drive unit may include controls in the speed loop, such as a proportional-integral controller.

[0012] In embodiments of this method, generating velocity data may include using a trajectory generator to generate preliminary velocity data and preliminary position data.

[0013] In one embodiment of the method, the method may further include the step of providing speed data to controls of the crane's drive unit. This method can thus advantageously provide a speed control mode for the drive unit.

[0014] In one embodiment of the method, the method may further include the step of providing preliminary speed data to the control of the crane's drive unit.

[0015] In one embodiment of the method, the crane may be a stacker crane.

[0016] In one embodiment of the method, the crane may be an overhead crane.

[0017] In one embodiment of the method, the crane may be a tower crane or a gantry crane.

[0018] In one embodiment of the method, the drive unit may include at least one drive shaft.

[0019] Another aspect of this disclosure relates to an apparatus for operating a crane, the apparatus comprising:

[0020] The generation unit is configured to generate speed data for the crane's drive unit, thereby suppressing the crane's oscillations.

[0021] A providing unit is configured to provide a compatibility model, the compatibility model being configured to describe the relationship between input speed data of the crane's drive unit and output position data of the crane's drive unit;

[0022] The determination unit is configured to determine the position data of the crane's drive unit by inputting the speed data into the compatibility model;

[0023] A providing unit is configured to provide position data of the crane's drive unit to the control of the crane's drive unit;

[0024] The control is configured to control the crane's drive unit based on the provided position data.

[0025] Another aspect of this disclosure relates to a system comprising:

[0026] The device for operating a crane as described above;

[0027] crane.

[0028] In one embodiment, the system may be provided, wherein the crane may be a stacker crane or an overhead crane.

[0029] The final aspect of this disclosure relates to a computer program unit that, when executed by a processor, is configured to perform the methods described above, and / or control the means described above, and / or control the system described above.

[0030] definition

[0031] The term "crane" must be understood broadly and refers to any material handling system with hooks and / or crane ropes. A crane can be an overhead crane, mast / stacking crane, trolley crane, etc. A crane may include at least one drive unit.

[0032] The term "drive unit" must be understood broadly and specifically refers to a drive unit for a crane configured to move the crane from one spatial position to another. The drive unit may include at least one control and at least one drive shaft.

[0033] The term drive shaft must be understood broadly and specifically refers to electromechanical motors and gears configured to generate mechanical movement of part or all of a crane. Drive shafts can be ball screw drives, planetary rack and pinion drives, winch motors, belt drives, etc. A crane may have one or more drive shafts.

[0034] The term "speed reference data" must be understood broadly and specifically refers to any data configured to control the speed of a drive unit or drive shaft. More specifically, the term "speed reference data" as used herein refers to speed reference data configured to suppress load oscillations in a crane. Speed ​​reference data can be derived from a speed data (i.e., speed level) input shaper configured to modify initial speed data to suppress load oscillations. Speed ​​reference data serves as a reference variable for speed control.

[0035] The term "position reference data" must be understood broadly and specifically refers to any data configured to control the position of the drive unit corresponding to the drive shaft. More specifically, the term "position reference data" as used herein refers to position reference data configured to be compatible with speed reference data when used in the corresponding feedback control. Position reference data can be derived from the compatibility model described below. Position reference data is used as a reference variable for position control.

[0036] The terms "preliminary position data" and "preliminary velocity data" used herein must be understood broadly and specifically refer to the position and velocity of the corresponding drive units of compatible drive shafts. Preliminary position data and preliminary velocity data can be generated using a trajectory / profile generator. Preliminary position data can be generated by integrating the preliminary velocity data.

[0037] The terminology compatibility model must be understood broadly, and specifically refers to a model configured to describe the relationship between input speed reference data and output position reference data of a crane's drive unit. The compatibility model may include one or more equations of motion describing the crane's motion, where the crane may be described as a multibody system (e.g., hook, rope, bridge, etc.). The compatibility model may include functions for calculating position reference data based on the input speed reference data, where the calculated position reference data is compatible with the input speed reference data. The calculation of the position reference data may also consider preliminary position data. Preliminary position data can be generated by integrating preliminary speed data. The preliminary position data can be adapted to be compatible with preliminary speed data. The calculated or determined position reference data is compatible with the speed reference data. Both the speed reference data and the position reference data can be used to control the drive unit in the corresponding feedback control.

[0038] The term "control" must be understood broadly and includes any logic configured to execute programs to perform the steps of the methods described above. This control may be part of the corresponding drive unit for the drive shaft.

[0039] The term "control" must be understood broadly and refers to any control configured to control the position and / or speed loops of the drive unit corresponding to the drive shaft. A control may include one or more proportional, integral, and derivative terms.

[0040] The term proportional controller refers to a feedback control configured to control the position loop of a drive unit corresponding to a drive shaft. A proportional controller includes a proportional term for controlling the position loop.

[0041] The term proportional-integral (PI) controller refers to a feedback controller configured to control the speed loop of a drive unit corresponding to a drive shaft. A PI controller includes a proportional term and an integral term for controlling the speed loop.

[0042] The term position control mode must be understood broadly, and in particular refers to control modes with a drive unit having position as a reference variable.

[0043] The term speed control mode must be understood broadly, and in particular, refers to the control mode of the drive unit with speed as the reference variable.

[0044] The term anti-sway mode must be understood broadly and specifically refers to the control mode of a drive unit configured to suppress load oscillations.

[0045] The units and / or devices according to one or more example embodiments can be implemented using hardware, software, and / or combinations thereof. For example, the hardware devices can be implemented using processing circuitry such as, but not limited to, processors, central processing units (CPUs), controllers, arithmetic logic units (ALUs), digital signal processors, microcomputers, field-programmable gate arrays (FPGAs), system-on-a-chip (SoCs), programmable logic units, microprocessors, or any other means of responding to and executing instructions in a defined manner.

[0046] A unit or device may include one or more interface circuits. In some examples, the interface circuit may include a wired or wireless interface connected to a local area network (LAN), the Internet, a wide area network (WAN), or a combination thereof. The functionality of any given device or unit of this disclosure may be distributed among multiple units or devices connected via interface circuits.

[0047] The units and / or devices according to one or more example embodiments may further include one or more storage devices. The one or more storage devices may be tangible or non-transitory computer-readable storage media, such as random access memory (RAM), read-only memory (ROM), permanent mass storage devices (e.g., disk drives), solid-state (e.g., NAND flash memory) devices, and / or any other similar data storage institution capable of storing and recording data. The one or more storage devices may be configured to store computer programs, program code, instructions, or some combination thereof.

[0048] Any disclosures and embodiments described herein relate to the methods, systems, apparatuses, computer program units listed above, and vice versa. Advantageously, the benefits provided by any embodiments and examples are equally applicable to all other embodiments and examples, and vice versa.

[0049] As used herein, “determine” also includes “initiating or causing determination,” “generate” also includes “initiating or causing generation,” and “provide” also includes “initiating or causing determination, generation, selection, sending, or receiving.” “Initiating or causing an action” includes any processing signal that triggers a computing device to perform a corresponding action.

[0050] Figure Labels

[0051] S100 generates speed data for the crane's drive unit.

[0052] S110 provides a compatibility model

[0053] S120 Determines Location Data

[0054] S130 provides position data and controls the crane's drive unit based on that position data.

[0055] 200 devices

[0056] 210 Generation Unit

[0057] 220 First Providing Unit

[0058] 230 Determining Unit

[0059] 240 Second Providing Unit

[0060] 250 control

[0061] 300 Reference Signal Generator

[0062] 310 Speed ​​Horizontal Input Shaper

[0063] 320 compatibility model

[0064] 330 Controls

[0065] 340 crane Attached Figure Description

[0066] In the following description, the present disclosure is illustrated by way of example with reference to the accompanying drawings, wherein

[0067] Figure 1 A flowchart illustrating an example method for operating a crane is shown;

[0068] Figure 2 A schematic diagram of an example device for operating a crane is shown; and

[0069] Figure 3 A conceptual diagram of an example device for operating a crane is shown. Detailed Implementation

[0070] Figure 1 A flowchart is shown for an example method of operating a crane.

[0071] Step S100 includes generating speed reference data for the crane's drive unit, thereby suppressing crane oscillations (S100). Generating the speed reference data may include using a trajectory generator to generate preliminary speed and position data. Generating the speed reference data may include using a speed data input shaper configured to modify the preliminary speed data, thereby suppressing load oscillations. The crane may be an overhead crane, a stacker crane, or a tower crane. The drive unit may include one or more drive shafts.

[0072] Step S110 includes providing a compatibility model configured to describe the relationship between the input speed reference data of the crane's drive unit and the output position reference data of the crane's drive unit (S110).

[0073] Step S120 includes determining the position data of the crane's drive unit by inputting speed reference data into the compatibility model (S120).

[0074] Step S130 includes providing position reference data of the crane's drive unit to the control of the crane's drive unit, and controlling the crane's drive unit according to the position reference data (S130). The control of the crane's drive unit may include a proportional controller in the position loop. The control of the crane's drive unit may include a proportional-integral controller in the speed loop.

[0075] This method can be executed separately in the control of the drive unit and the control of the drive shaft. Optionally, the method may further include the step of providing speed reference data to the control of the crane's drive unit. Optionally, the method may further include the step of providing preliminary speed data to the control of the crane's drive unit. Optionally, the method may further include the step of selecting one or more of the following position control mode, speed control mode, and anti-sway control mode.

[0076] Figure 2 A schematic diagram of an example device 200 for operating a crane is shown.

[0077] The device 200 includes a generation unit (210) configured to generate speed reference data for the drive unit of the crane, thereby suppressing oscillations of the crane; a first providing unit (220) configured to provide a compatibility model described in terms of the relationship between input speed reference data and output position reference data of the crane's drive unit; a determining unit (230) configured to determine position reference data of the crane's drive unit by inputting the speed reference data into the compatibility model; a second providing unit (240) configured to provide the position reference data of the crane's drive unit to a control of the crane's drive unit; and a control (250) configured to control the crane's drive unit based on the position reference data.

[0078] Figure 3A conceptual diagram of an example apparatus for operating a crane is shown. A reference signal generator 300 can generate preliminary position data and preliminary speed data. A speed level input shaper 310 can generate speed reference data by processing the preliminary speed data, thereby suppressing oscillations. A compatibility model 320 can determine position reference data by inputting the speed reference data into the compatibility model 320 and optionally by inputting the preliminary position data. A control 330 can control the drive unit of the crane 340 based on the position reference data and optionally on the speed reference data.

[0079] The main effects and key advantages of this disclosure are summarized below:

[0080] The proposed invention may include a drive-based solution for integrating position control and anti-sway functionality (i.e., anti-sway control mode) into cranes or any material handling application, particularly when the load acts as an oscillating mass block. Optionally, the invention may also include a PLC-based solution.

[0081] Typically, anti-sway functionality is available in speed control mode, such as for manual crane operation. Position control (required for autonomous operation) is usually implemented on an external control system (e.g., a PLC). This external position control interferes with anti-sway functionality.

[0082] The proposed solution is computationally sleek and can be fully integrated into the drive unit, requiring no additional sensing (purely software-based). The concept is modular, as the same control 250 can be used for anti-sway mode, speed control mode, and position control mode.

[0083] Furthermore, this concept can be independent of crane type and can be applied to overhead cranes, stacker cranes, and tower cranes.

[0084] One of the major challenges in controlling a crane is load oscillation. When accelerating a bridge or haulage vehicle, the load (or the tip of a stacker crane) may inevitably begin to oscillate.

[0085] Anti-sway (or anti-glide) control schemes aim to suppress such oscillations. Typically, an input shaper can be used, which modifies the original speed data so that load oscillations are offset. Speed ​​control is sufficient for manual crane operation (i.e., the operator can provide speed data using input devices such as buttons or joysticks). However, in automated warehouses, for example, automated crane operation may become more critical. Automated operation may require position control of the crane. The problem with simply closing the external position loop around the speed-controlled crane is that the position controller may compete with both the speed control mode and the anti-sway control mode. Therefore, suppression of load oscillations cannot be achieved.

[0086] The proposed solution addresses this issue by allowing for the complete integration of position control and anti-sway control modes within the drive unit. This concept is modular (suitable for both position and speed control), requires no sensors, and can be applied to both overhead cranes and stacker cranes. Internally, it can have built-in functionality to allow users to switch between different modes, such as speed control only, speed control + anti-sway control, or speed / anti-sway control & position control.

[0087] Greater application safety can be achieved when the application (load) does not swing uncontrollably and cause damage to crane components.

[0088] Higher material handling efficiency can be achieved when the application does not require waiting time at the target location for the load to stop swaying before performing final positioning. Integrating the solution into the drive can be a cost-effective solution, but it is also more robust.

[0089] The proposed solution can be composed of four main modules:

[0090] a) A trajectory / contour generator for generating smooth, initial position and velocity data that are compatible with each other (i.e., position data can be an integral of velocity data). A common approach is acceleration-constrained trajectory generation.

[0091] (b) A standard cascade with optional acceleration / torque feedforwards for tracking position and velocity reference data (e.g., a proportional controller in the external position loop and a proportional-integral controller in the internal velocity loop). The proportional position controller can be fed the difference between the position reference data and the actual position data and can generate a component of the velocity reference data (i.e., the output). The proportional-integral controller can be fed the difference between the position controller output and the actual velocity data. Furthermore, a velocity feedforward signal can be added to the input of the velocity control to reduce tracking errors. Optionally, a torque feedforward signal can be added to the velocity controller output.

[0092] c) A velocity data input shaper (i.e., a velocity level input shaper) is used to modify the initial velocity data to suppress load oscillations. The input shaper can be obtained by convolving the input with a Dirac pulse sequence. If an unshaped input excites oscillations in the system, the idea is to shape the input so that the system is excited multiple times, but the resulting oscillations cancel each other out. The input shaper can be one of the following: a two-pulse ZV shaper (“zero vibration”), a three-pulse ZVD shaper (“zero vibration and damping”), or a four-pulse ETM4 shaper (“equal shaping time and magnitude”). The oscillation time can depend on the mechanical characteristics of the existing system and can vary with rope length (overhead crane) or lifting position (stacking crane). However, the input shaper can be adjusted during operation using a known or approximate relationship between rope length / lifting position and oscillation time.

[0093] d) A position reference modulator for ensuring that position reference data and velocity reference data remain compatible.

[0094] A position reference modulator (i.e., a compatibility model) can notify the position controller of modifications to the velocity reference data. Therefore, this method ensures that the position and velocity reference data remain compatible, and thus guarantees that position control and velocity data input shaping do not compete with or interfere with each other. This method can be fully integrated into the drive unit.

[0095] The position reference modulator calculates the difference between the shaped velocity reference data and the original velocity reference data (i.e., the preliminary velocity data). This difference can be fed into an integrator. The integrator output can be added to the original position reference (i.e., the preliminary position data) before being fed into the position control. As a result, the position reference data and velocity reference data ultimately sent to the P-PI servo cascade for tracking can be compatible. Therefore, the anti-sway components in the outer loop position controller and velocity control can avoid competing with each other.

Claims

1. A computer-implemented method for operating a crane, comprising the following steps: Speed ​​reference data for the drive unit of the crane is generated so that the oscillation of the crane is suppressed (S100). A compatibility model is provided, which is configured to describe the relationship between the input speed reference data of the crane's drive unit and the output position reference data of the crane's drive unit (S110). The position reference data of the drive unit of the crane is determined by inputting the speed reference data into the compatibility model (S120). The position reference data of the drive unit of the crane is provided to the control of the drive unit of the crane, and the drive unit of the crane is controlled according to the position reference data (S130). The generation of the velocity reference data includes using a trajectory generator to generate preliminary velocity data and preliminary position data.

2. The method of claim 1, wherein the control of the drive unit of the crane includes a proportional controller in a position loop.

3. The method according to any one of claims 1-2, wherein the control of the drive unit of the crane includes a proportional-integral controller in the speed loop.

4. The method according to any one of claims 1-2, further comprising the step of providing the speed reference data to the control of the drive unit of the crane.

5. The method of claim 4, further comprising the step of providing the preliminary speed data to the control of the drive unit of the crane.

6. The method according to any one of claims 1-2, wherein the crane is a stacker crane.

7. The method according to any one of claims 1-2, wherein the crane is an overhead crane.

8. The method according to any one of claims 1-2, wherein the crane is a tower crane or a gantry crane.

9. The method according to any one of claims 1-2, wherein the drive unit comprises at least one drive shaft.

10. A device (200) for operating a crane, comprising: A generation unit (210) is configured to generate speed reference data for the drive unit of the crane, thereby suppressing the oscillation of the crane; A first providing unit (220) is configured to provide a compatibility model, which is configured to describe the relationship between input speed reference data of the crane's drive unit and output position reference data of the crane's drive unit; Determining unit (230), the determining unit is configured to determine the position reference data of the drive unit of the crane by inputting the speed reference data into the compatibility model; A second providing unit (240) is configured to provide the position reference data of the drive unit of the crane to the control of the drive unit of the crane; The control (250) is configured to control the drive unit of the crane based on the position reference data. The generation of the velocity reference data includes using a trajectory generator to generate preliminary velocity data and preliminary position data.

11. A system comprising the means for operating a crane according to claim 10, further comprising: crane.

12. The system of claim 11, wherein the crane is a stacker crane, an overhead crane, or a tower crane.

13. A computer program unit, which, when executed by a processor, is configured to perform the method according to any one of claims 1 to 9, or to control the apparatus according to claim 10, or to control the system according to claim 11 or 12.

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