Semi-physical simulation system and method for multi-dimensional active motion compensation crane

Abstract

The invention discloses a semi-physical simulation system of a multi-dimensional active motion compensation crane. The semi-physical simulation system of the multi-dimensional active motion compensation crane comprises a left linkage table, a right linkage table, a driving seat, a man-machine interaction screen and implementation hardware. The left linkage table and the right linkage table are used for controlling a multi-dimensional active motion compensation crane model, the driving seat is fixedly connected between the left linkage table and the right linkage table, and the man-machine interaction screen is respectively interconnected with the left linkage table and the right linkage table. The invention further discloses a semi-physical simulation method of the multi-dimensional active motion compensation crane. According to the semi-physical simulation system and method for the multi-dimensional active motion compensation crane, real-time simulation of the multi-dimensional active motion compensation crane is achieved, and simulation testing can be conducted on the crane performance under various complex sea conditions on a virtual platform.

Description

Technical Field

[0001] The present invention relates to the field of simulation testing technology, and more specifically, to a semi-physical simulation system and method for a multi-dimensional active motion compensation crane. Background Art

[0002] Multi-dimensional active motion compensation cranes can be used in wind power operation and maintenance ships, offshore support vessels and other marine engineering fields for material transfer. As the core operating equipment of wind power operation and maintenance ships, they are responsible for the material transfer between the operation and maintenance mother ship and the wind turbines. The debugging of multi-dimensional active motion compensation cranes cannot be simulated in the traditional development process, and needs to be tested and optimized at sea after production is completed. However, the marine environment is complex and changeable, and is subject to factors such as weather and sea conditions. The test process cannot cover the complete use environment, and various extreme working conditions will also be dangerous.

[0003] With the rapid development of electronic technology, hardware online technology combined with computer simulation systems has been widely used in various industrial development and design processes. However, the field of simulation testing for multi-dimensional active motion compensation cranes is still in urgent need of development and lacks corresponding technical products. Summary of the invention

[0004] The purpose of the present invention is to provide a semi-physical simulation system and method for a multi-dimensional active motion compensation crane, which solves the technical problem that the simulation test of the multi-dimensional active motion compensation crane cannot be simulated in the traditional development process, and can simulate the performance of the crane under various complex sea conditions on a virtual platform.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A semi-physical simulation system of a multi-dimensional active motion compensation crane comprises a left linkage platform, a right linkage platform, a driving seat, a human-machine interaction screen and implementation hardware; the left linkage platform and the right linkage platform control a multi-dimensional active motion compensation crane model, the driving seat is fixedly connected between the left linkage platform and the right linkage platform, and the human-machine interaction screen is interconnected with the left linkage platform and the right linkage platform respectively.

[0007] Furthermore, the left linkage platform includes a left handle, an aisle light button, a floodlight button, a main pump start light button, a mute button, a test light button, a main pump stop button, a buzzer, an overload indicator light, a standby selection switch, a standby selection switch light button, a loose rope bypass key switch and a position bypass key switch.

[0008] Furthermore, the right linkage platform includes a right handle, a manual overload protection system MOPS, an automatic overload protection system AOPS emergency operation button, a control closing button with light, an active compensation start button with light, a CT start button with light, a fault reset button with light, a CT given knob, a MOPS indicator light, an AOPS indicator light, a limit indicator light, a control off button, an active compensation stop button, a constant tension mode selection switch and a limit bypass key switch.

[0009] Furthermore, the right linkage platform is also provided with an HMI panel, which can view the operating data and status of each mechanism, diagnostic information and threshold alarm signals as needed.

[0010] Furthermore, the human-computer interaction screen is formed by splicing five narrow-edge screens in special shapes, and the human-computer interaction screen can be adjusted up and down; the five narrow-edge screens use a screen splitter to distribute the video signal source output by a simulation system.

[0011] Furthermore, the implementation hardware includes PLC, distributed IO, human-computer interaction interface, industrial computer and visualization platform; the PLC communicates with the distributed IO via Profinet field bus, and the PLC is electrically connected to the human-computer interaction interface, the industrial computer and the visualization platform respectively.

[0012] The present invention also provides a semi-physical simulation method of a multi-dimensional active motion compensation crane, comprising the following steps:

[0013] S1. Establish a coordinate system for the specific operation of the multi-dimensional active motion compensation crane, and perform coordinate calculations on the semi-physical simulation platform of the multi-dimensional active motion compensation crane according to the coordinate system parameter table;

[0014] S2. Specific operation procedures of multi-dimensional active motion compensation crane.

[0015] Furthermore, the S1 comprises the following steps:

[0016] S11. Establish the coordinate system of the multi-dimensional active motion compensation crane. At the installation location of the multi-dimensional active motion compensation crane, establish the coordinate system 0, and at the motion center of the i-th control mechanism of the crane, establish the corresponding coordinate system i that moves with the control mechanism;

[0017] S12. According to the coordinate system parameter table, establish a homogeneous transformation matrix from coordinate system i to coordinate system i-1 According to the transformation matrix outer multiplication method, the homogeneous transformation matrix from coordinate system 3 to coordinate system 0 is determined.

[0018]

[0019] Among them, L0, θ1, and d2 are the movement strokes of the three control mechanisms, L1 is the main boom length, and θ0 is the amplitude angle;

[0020] S13. In a given control mechanism stroke, the forward motion equation calculates the coordinate value of the multi-dimensional active motion compensation crane hoisting mechanism in the base coordinate system 0;

[0021]

[0022] in, It is the coordinate value of the crane hoisting mechanism in coordinate system 0.

[0023] Further, the S2 comprises the following steps:

[0024] S21. Before formally operating the multi-dimensional active motion compensation crane, confirm the linkage table indicator light through the test light button;

[0025] S22. Provide the marine environment test parameters on the human-computer interaction interface;

[0026] S23. After confirming that the left linkage indicator light and the right linkage indicator light are not faulty and the parameters are correct, start the control light button and the main pump start button;

[0027] S24. Choose whether to start the active compensation start light button according to actual operation needs;

[0028] S25. Control each mechanism of the multi-dimensional active motion compensation crane through the left handle and the right handle, and observe and record the operating status of each mechanism of the multi-dimensional active motion compensation crane through the human-machine interaction screen and the HMI panel;

[0029] S26. During the operation, choose whether to start the constant tension mode according to the working conditions. To start the constant tension mode, you need to start the selection switch first, then press the CT start button with light, and determine the tension size through the CT given knob.

[0030] Furthermore, during the operation in S26, the working conditions are mainly divided into the following two types:

[0031] S261. During the movement of an empty or loaded vehicle, the predetermined trajectory is completed through position control or speed control.

[0032] S262. When the cargo is being hoisted and has not yet left the supporting surface, use the constant tension mode to start the cargo away from the supporting surface to prevent sudden changes in load from causing impact on the multi-dimensional active motion compensation crane.

[0033] By adopting the above technical solution, the present invention has the following advantages:

[0034] 1. The present invention provides a semi-physical simulation system for a multi-dimensional active motion compensation crane, which realizes real-time simulation of the multi-dimensional active motion compensation crane and can simulate and test the crane performance under various complex sea conditions on a virtual platform.

[0035] 2. The present invention provides a semi-physical simulation system for a multi-dimensional active motion compensation crane, which is consistent with the actual crane cab structure; at the same time, it is equipped with a human-computer interaction screen, which can simulate the first-person perspective of the driver under actual operating conditions in real time, making the test process more realistic. All hardware facilities are integrated into the semi-physical simulation system, and the entire simulation process is completed through PLC and industrial computer, realizing hardware-in-the-loop semi-physical simulation.

[0036] 3. The present invention provides a semi-physical simulation system for a multi-dimensional active motion compensation crane. The PLC communicates with the distributed IO through the Profinet field bus, realizes real-time data exchange with the multi-dimensional active motion compensation crane control system through the IO interface, receives the mechanism operation instructions issued by the control system, and outputs signals to the dynamic simulation module. The dynamic simulation part mainly consists of hydraulic system simulation, marine test environment simulation and offshore crane motion simulation.

[0037] 4. The present invention also provides a semi-physical simulation method for a multi-dimensional active motion compensation crane, which establishes a multi-dimensional coordinate system for each motion mechanism, and sets the crane installation position as the base coordinate system 0. According to the relative motion relationship between the mechanisms, the homogeneous transformation matrix between the coordinate systems can be obtained, and the forward motion equation of each mechanism relative to the base coordinate system can be obtained through the transformation matrix. Therefore, the relative position and posture of the front end of the crane can be obtained by the established forward motion equation, and the motion simulation of the offshore crane can be realized, completing the motion control closed loop.

[0038] 5. The present invention also provides a semi-physical simulation method for a multi-dimensional active motion compensation crane. The control system consists of three control modes: position control, speed control, and force control. The appropriate mode is selected according to the actual working conditions to be achieved to control the proportional valves and servo valves of each operating mechanism, so that the crane runs according to the predetermined trajectory.

[0039] 6. The present invention also provides a semi-physical simulation method for a multi-dimensional active motion compensation crane, which integrates real-time simulation of multiple physical processes in terms of load and environmental interaction, and selects various sea conditions for testing through a human-computer interaction interface. By adopting simplified dynamic modeling of ropes, the dynamic characteristics of ropes under different loads can be simulated; simplifying the wind dynamics model, balancing the credibility of real-time calculation and wind disturbance; and using a state machine model to accurately control the operating state and transfer conditions of the spreader. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Other features, objectives and advantages of the present invention will become more apparent from a reading of the detailed description of non-limiting embodiments made with reference to the following accompanying drawings.

[0041] Figure 1 It is the layout diagram of the semi-physical simulation system of the multi-dimensional active motion compensation crane;

[0042] Figure 2 It is a three-dimensional structural diagram of the human-computer interaction screen of the present invention;

[0043] Figure 3 is a working principle diagram of the implementation hardware of the present invention;

[0044] Figure 4 is a schematic diagram of the crane motion coordinate system of the present invention;

[0045] Figure 5 is a control block diagram of a position control mode of a control system of the present invention;

[0046] Figure 6 is a control block diagram of a speed control mode of the control system of the present invention;

[0047] Figure 7 It is a control block diagram of the force control mode of the control system of the present invention. DETAILED DESCRIPTION

[0048] The technical solution of the present invention is specifically described below in conjunction with the drawings in the specification. The detailed features and advantages of the present invention are described in detail in the specific implementation mode. The content is sufficient to enable any technical personnel in the field to understand the technical content of the present invention and implement it accordingly. According to the description, claims and drawings disclosed in this specification, the technical personnel in the field can easily understand the relevant purposes and advantages of the present invention.

[0049] A semi-physical simulation system for a multi-dimensional active motion compensation crane is specifically described as follows: Figure 1 As shown, it includes a left linkage platform 1, a right linkage platform 2, a driving seat 3, a human-machine interaction screen and implementation hardware; the left linkage platform 1 and the right linkage platform 2 control the multi-dimensional active motion compensation crane model, which is divided into a main crane and a motion compensation mechanism attached to the top of the crane, so the left linkage platform 1 and the right linkage platform 2 will distinguish the operation of the two mechanisms. The driving seat 3 is fixedly connected between the left linkage platform 1 and the right linkage platform 2, and the human-machine interaction screen is interconnected with the left linkage platform 1 and the right linkage platform 2 respectively.

[0050] The left linkage platform 1 includes a left handle, a walkway light button, a floodlight button, a main pump start lighted button, a mute button, a test light button, a main pump stop button, a buzzer, an overload indicator light, a standby selection switch, a standby selection switch lighted button, a loose rope bypass key switch and a position bypass key switch.

[0051] Among them, the left handle 1 is equipped with two, which are responsible for the control of the main luffing / slewing and the upper luffing / slewing respectively; one aisle light button, one floodlight button and one main pump start lighted button; one buzzer; one overload indicator light; one mute button, one test light button and one main pump stop button; one rope loose bypass key switch and one position bypass key switch; one standby selection switch and one standby selection switch lighted button.

[0052] The right linkage platform 2 includes a right handle, a manual overload protection system MOPS, an automatic overload protection system AOPS emergency operation button, a control closing button with light, an active compensation start button with light, a CT start button with light, a fault reset button with light, a CT given knob, a MOPS indicator light, an AOPS indicator light, a limit indicator light, a control off button, an active compensation stop button, a constant tension mode selection switch and a limit bypass key switch.

[0053] Among them, there are two right handles, which are responsible for the control of the main lifting / extension and the upper lifting / extension respectively; there are also one emergency operation button each for the manual overload protection system MOPS and the automatic overload protection system AOPS; one control closing button with light, one active compensation start button with light, one CT start button with light and one fault reset button with light; one CT given knob; one MOPS indicator light, one AOPS indicator light and one limit indicator light; one control off button and one active compensation stop button; one constant tension mode selection switch; and one limit bypass key switch.

[0054] The three-dimensional structure diagram of the human-computer interaction screen 4 is as follows Figure 2 As shown, the human-computer interaction screen 4 is composed of five 55-inch narrow-edge screens spliced ​​together. A screen splitter is used to distribute the video signal source output by one simulation system to the five display screens and distribute the images. The splicing status is as follows: Figure 2 The entire display screen of the human-machine interaction screen 4 can be adjusted up and down, and the angles of the four upper, lower, left and right screens of the five 55-inch narrow-edge screens can also be fine-tuned to better suit the visual experience of the operator and truly reflect the on-site driver's room operation.

[0055] When using the simulation test system, the operation process is consistent with the actual crane driving process, and the tester can directly control the motion of each mechanism through the left handle, right handle and buttons. In addition, the right linkage platform 2 is also equipped with an HMI panel, which can view the operation data and status of each mechanism, diagnostic information, threshold alarm signals, etc. according to needs.

[0056] The implementation hardware includes PLC, distributed IO, human-computer interaction interface, industrial computer and visualization platform. Its working principle is as follows Figure 3As shown in the figure, the PLC is electrically connected to the human-machine interface, industrial computer, and visualization platform. The PLC communicates with the distributed IO through the Profinet fieldbus, collects field signal feedback, processes it, and then transmits part of the information to the industrial computer through OPC-UA. After receiving the information, the industrial computer processes the dynamic model, and sends the processing result dynamic model to the real-time simulation system and displays it on the visualization platform. The human-machine interface displays the status information and fault information of each mechanism simulated by the simulation system in real time. It can also adjust the test parameters or switch different environmental variables such as waves, swells, flow, wind speed, etc. as needed.

[0057] A semi-physical simulation method for a multi-dimensional active motion compensation crane comprises the following steps:

[0058] S1. Establish the coordinate system for the specific operation of the multi-dimensional active motion compensation crane. Figure 4 As shown, according to the coordinate system parameter table, coordinate calculation of the semi-physical simulation platform of the multi-dimensional active motion compensation crane is performed;

[0059] S1 includes the following steps:

[0060] S11. Establish the coordinate system of the multi-dimensional active motion compensation crane. At the installation location of the multi-dimensional active motion compensation crane, establish coordinate system 0, and at the motion center of the i-th control mechanism of the crane, establish the corresponding coordinate system i that moves with the control mechanism; the number of coordinate systems is 4, coordinate system 0 is the base coordinate system, coordinate systems 1-3 correspond to the coordinate systems of each control mechanism, and coordinate system 4 is related to the lifting motion of the crane.

[0061] S12. According to the coordinate system parameter table, establish a homogeneous transformation matrix from coordinate system i to coordinate system i-1 According to the transformation matrix outer multiplication method, the homogeneous transformation matrix from coordinate system 3 to coordinate system 0 is determined.

[0062]

[0063] Among them, L0, θ1, and d2 are the movement strokes of the three control mechanisms, L1 is the main boom length, and θ0 is the amplitude angle;

[0064] S13. In a given control mechanism stroke, the forward motion equation calculates the coordinate value of the multi-dimensional active motion compensation crane hoisting mechanism in the base coordinate system 0;

[0065]

[0066] in, It is the coordinate value of the crane hoisting mechanism in coordinate system 0.

[0067] like Figure 4As shown, coordinate system 1 moves with the slewing mechanism, coordinate system 2 moves with the telescopic mechanism, and coordinate system 3 controls the lifting movement. Figure 4 The coordinate system of coordinate system 3 to coordinate system 0 is determined as:

[0068] The forward motion equation is:

[0069]

[0070] The control system uses Siemens ET200SP series PLC modules as the main control hardware, in which the TMpulse module is used to perform PWM control on the proportional valve, and the high-speed AI / AO module is used to communicate the servo valve control output and feedback information. The valve is PID controlled through the above-mentioned modules to achieve the required control effect. In addition, the control system uses a safety PLC to control operations that require a higher safety level, such as emergency stop, overspeed, and limit, to meet the safety specifications required for offshore operations.

[0071] In the present invention, the three mechanisms of main variable amplitude, compensation telescopic and compensation lifting are controlled by servo valves, and position control, speed control and force control are required. The control block diagrams of the three control modes of position control, speed control and force control are as follows: Figure 5 , Figure 6 , Figure 7 As shown in the figure, due to the large relative hysteresis of hydraulic control, speed feedforward control is added to reduce the response time compared to conventional closed-loop feedback control. The speed feedforward term includes the reference speed and the actual speed. PD control is commonly used in position control. If the integral term is introduced, the system will be unstable. However, since the viscous resistance is large when the speed is close to 0, the integral term will be used to overcome the resistance in this case; PI control is used for speed control; PI control is also used in force control mode, and a load sensor is used to obtain actual feedback.

[0072] S2. Specific operation procedures of multi-dimensional active motion compensation crane.

[0073] S2 includes the following specific steps:

[0074] S21. Before formally operating the multi-dimensional active motion compensation crane, confirm the linkage table indicator light through the test light button;

[0075] S22. Provide the marine environment test parameters on the human-computer interaction interface;

[0076] S23. After confirming that the left linkage indicator light and the right linkage indicator light are not faulty and the parameters are correct, start the control light button and the main pump start button;

[0077] S24. Choose whether to start the active compensation start light button according to actual operation needs;

[0078] S25. Control each mechanism of the multi-dimensional active motion compensation crane through the left handle and the right handle, and observe and record the operating status of each mechanism of the multi-dimensional active motion compensation crane through the human-machine interaction screen and the HMI panel;

[0079] S26. During the operation, choose whether to start the constant tension mode according to the working conditions. To start the constant tension mode, you need to start the selection switch first, then press the CT start button with light, and determine the tension size through the CT given knob.

[0080] During the operation of S26, the working conditions are mainly divided into the following two types:

[0081] S261. During the movement of an empty or loaded vehicle, the predetermined trajectory is completed through position control or speed control.

[0082] S262. When the cargo is being hoisted and has not yet left the supporting surface, use the constant tension mode to start the cargo away from the supporting surface to prevent sudden changes in load from causing impact on the multi-dimensional active motion compensation crane.

[0083] In addition, the load and environment interaction part includes rope dynamics, wind simulation, sling operation state machine, etc., which mainly rely on writing differential equations to achieve simulation.

[0084] The rope dynamics need to be simplified accordingly. Simplifying the rope-load into a variable length pendulum model can effectively simulate the dynamic characteristics of the rope in actual operation. By setting appropriate elasticity and damping parameters, the deformation and vibration behavior of the rope under different loads can be simulated.

[0085] The spreader operation will be modeled using a state machine model, such as lifting, moving, lowering and other operating states. By setting trigger events, the collisions and obstacles that the spreader may encounter during different operations can be simulated, and the operation instructions can be responded to in real time.

[0086] Finally, it should be pointed out that although the present invention has been described with reference to the current specific embodiments, ordinary technicians in this technical field should realize that the above embodiments are only used to illustrate the present invention and are not used as a limitation of the present invention. Various equivalent changes or substitutions can be made without departing from the concept of the present invention. Therefore, as long as the changes and modifications to the above embodiments are within the essential spirit of the present invention, they will fall within the scope of the claims of the present invention.

Claims

1. A semi-physical simulation system for a multi-dimensional active motion compensation crane, characterized in that: It includes a left linkage platform, a right linkage platform, a driving seat, a human-machine interaction screen and implementation hardware; the left linkage platform and the right linkage platform control the multi-dimensional active motion compensation crane model, the driving seat is fixedly connected between the left linkage platform and the right linkage platform, and the human-machine interaction screen is interconnected with the left linkage platform and the right linkage platform respectively.

2. A semi-physical simulation system for a multi-dimensional active motion compensation crane according to claim 1, characterized in that: The left linkage platform includes a left handle, a walkway light button, a floodlight button, a main pump start light button, a mute button, a test light button, a main pump stop button, a buzzer, an overload indicator light, a standby selection switch, a standby selection switch light button, a loose rope bypass key switch and a position bypass key switch.

3. A semi-physical simulation system for a multi-dimensional active motion compensation crane as claimed in claim 2, characterized in that: The right linkage platform includes a right handle, a manual overload protection system MOPS, an automatic overload protection system AOPS emergency operation button, a control closing button with light, an active compensation start button with light, a CT start button with light, a fault reset button with light, a CT given knob, a MOPS indicator light, an AOPS indicator light, a limit indicator light, a control off button, an active compensation stop button, a constant tension mode selection switch and a limit bypass key switch.

4. A semi-physical simulation system for a multi-dimensional active motion compensation crane as claimed in claim 3, characterized in that: The right linkage station is also provided with an HMI panel, which can view the operating data and status of each mechanism, diagnostic information and threshold alarm signals as needed.

5. A semi-physical simulation system for a multi-dimensional active motion compensation crane as claimed in claim 4, characterized in that: The human-computer interaction screen is formed by splicing five narrow-edge screens in special shapes, and the human-computer interaction screen can be adjusted up and down; the five narrow-edge screens use a screen splitter to distribute the video signal source output by a simulation system.

6. A semi-physical simulation system for a multi-dimensional active motion compensation crane as claimed in claim 5, characterized in that: The implementation hardware includes PLC, distributed IO, human-computer interaction interface, industrial computer and visualization platform; the PLC communicates with the distributed IO via Profinet field bus, and the PLC is electrically connected to the human-computer interaction interface, the industrial computer and the visualization platform respectively.

7. A semi-physical simulation method for a multi-dimensional active motion compensation crane, characterized in that: The following steps are involved: S1. Establish a coordinate system for the specific operation of the multi-dimensional active motion compensation crane, and perform coordinate calculations on the semi-physical simulation platform of the multi-dimensional active motion compensation crane according to the coordinate system parameter table; S2. Specific operation procedures of multi-dimensional active motion compensation crane.

8. A semi-physical simulation method for a multi-dimensional active motion compensation crane according to claim 7, characterized in that: The S1 comprises the following steps: S11. Establish the coordinate system of the multi-dimensional active motion compensation crane. At the installation location of the multi-dimensional active motion compensation crane, establish the coordinate system 0, and at the motion center of the i-th control mechanism of the crane, establish the corresponding coordinate system i that moves with the control mechanism; S12. According to the coordinate system parameter table, establish a homogeneous transformation matrix from coordinate system i to coordinate system i-1 According to the transformation matrix outer multiplication method, the homogeneous transformation matrix from coordinate system 3 to coordinate system 0 is determined. Among them, L0, θ1, and d2 are the movement strokes of the three control mechanisms, L1 is the main boom length, and θ0 is the amplitude angle; S13. In a given control mechanism stroke, the forward motion equation calculates the coordinate value of the multi-dimensional active motion compensation crane hoisting mechanism in the base coordinate system 0; in, It is the coordinate value of the crane hoisting mechanism in coordinate system 0.

9. A semi-physical simulation method for a multi-dimensional active motion compensation crane according to claim 7, characterized in that: The S2 comprises the following steps: S21. Before formally operating the multi-dimensional active motion compensation crane, confirm the linkage table indicator light through the test light button; S22. Provide the marine environment test parameters on the human-computer interaction interface; S23. After confirming that the left linkage indicator light and the right linkage indicator light are not faulty and the parameters are correct, start the control light button and the main pump start button; S24. Choose whether to start the active compensation start light button according to actual operation needs; S25. Control each mechanism of the multi-dimensional active motion compensation crane through the left handle and the right handle, and observe and record the operating status of each mechanism of the multi-dimensional active motion compensation crane through the human-machine interaction screen and the HMI panel; S26. During the operation, choose whether to start the constant tension mode according to the working conditions. To start the constant tension mode, you need to start the selection switch first, then press the CT start button with light, and determine the tension size through the CT given knob.

10. A semi-physical simulation method for a multi-dimensional active motion compensation crane according to claim 9, characterized in that: During the operation in S26, the working conditions are mainly divided into the following two types: S261. During the movement of an empty load or a suspended load, the predetermined trajectory is completed by position control or speed control; S262. When the cargo is being hoisted and has not yet left the supporting surface, use the constant tension mode to start the cargo away from the supporting surface to prevent sudden changes in load from causing impact on the multi-dimensional active motion compensation crane.

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