Working machinery

Abstract

The present invention provides a crane capable of efficiently moving a suspended load to a target position while suppressing the swaying of the suspended load at the target position. [Solution] The crane is equipped with a slewing angular velocity setting unit 702. Based on the equations of motion of the suspended load in the slewing direction and radial direction, which include at least the length of the luffing body, the length of the suspension rope, and the luffing angle of the luffing body, the slewing angular velocity of the upper body until it reaches the target position is set to include a two-stage S-shaped trajectory in the acceleration and deceleration regions, respectively, so that the radial swing angle and slewing swing angle at the target position are smaller than a predetermined threshold angle and the time it takes for the suspended load to reach the target position is minimized.

Description

Technical Field

[0001] The present invention relates to a working machine capable of moving a suspended load.

Background Art

[0002] Conventionally, as a working machine, a crane is known that includes a lower traveling body, an upper revolving body supported by the lower traveling body so as to be capable of revolving around a vertical revolving center axis, and a hoisting body such as a boom or a jib. The hoisting body is attached to the front part of the upper revolving body so as to be capable of rotating in the hoisting direction around a horizontal rotation center axis. Further, a hook is attached to a suspended load rope suspended from the tip of the hoisting body, and the suspended load is lifted by connecting the suspended load to the hook. In a state where the suspended load is lifted in this way, when the upper revolving body revolves, the suspended load can be moved in the revolving direction.

[0003] Patent Documents 1 and 2 disclose a technique for linearly controlling the trajectory of the moving speed of a crane in order to reduce the load swing generated during the movement of a suspended load in a ceiling crane arranged in a building.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the technologies described in Patent Documents 1 and 2 relate to ceiling cranes, the sway of the suspended load to be considered occurs within a plane including the moving direction and the vertical direction of the crane. On the other hand, in the swiveling operation of the work machine, the suspended load swings in the swiveling direction (circumferential direction) and the radial direction. In particular, in the swiveling operation of the work machine, three-dimensional behavior of the suspended load including Coriolis force and centrifugal force occurs with respect to the suspended load. Therefore, even if the technologies described in Patent Documents 1 and 2 are applied to the work machine, it is difficult to stably reduce the sway of the suspended load that occurs in the swiveling operation of the work machine.

[0006] The present invention has been made in view of the above problems, and an object thereof is to provide a work machine capable of efficiently moving a suspended load to a target position by a swiveling operation and suppressing the sway of the suspended load at the target position.

Means for Solving the Problems

[0007] The present invention provides a work machine. The crane comprises a lower body, an upper body, a luffing body, a load rope, a slewing drive unit, a luffing body length information acquisition unit, a slewing angle detection unit, a rope length information acquisition unit, a movement information receiving unit, a speed setting unit, and a command signal generation unit. The upper body is supported on the lower body so as to be rotatable around a slewing center axis extending in the vertical direction. The luffing body includes a base end of the luffing body and a tip end of the luffing body opposite to the base end, both supported on the upper body so as to be rotatable in the luffing direction around a horizontal rotation center axis. The load rope hangs down from the tip end of the luffing body and is connected to a load. The slewing drive unit receives a predetermined angular velocity command signal and can rotate the upper body around the slewing center axis at a speed corresponding to the angular velocity command signal. The luffing body length information acquisition unit acquires luffing body length information, which is information corresponding to the length of the luffing body in the longitudinal direction of the luffing body, which is the direction connecting the base end and the tip end of the luffing body. The rotation angle detection unit detects the rotation angle of the upper body around the rotation center axis. The luffing angle detection unit detects the luffing body's luffing angle around the rotation center axis. The rope length information acquisition unit acquires rope length information, which is information corresponding to the length of the load rope between the tip end of the luffing body and the suspended load. The movement information receiving unit receives movement information, including a target rotation angle, to move the suspended load to a predetermined target position around the rotation center axis by the rotational movement of the upper body, starting from the initial state in which the suspended load is lifted by the load rope. If the angle of the suspension rope with respect to the vertical direction when the raised body is viewed along the rotational direction of the upper body is defined as the radial swing angle, and the angle of the suspension rope with respect to the vertical direction when the raised body is viewed along the radial direction of the rotational movement of the upper body is defined as the rotational swing angle, then the speed setting unit sets the angular velocity of the upper body to reach the target position to include multiple curved trajectories in each of the acceleration and deceleration regions, based on the equations of motion of the suspension load for each of the rotational and radial directions, which include at least the length of the raised body, the length of the suspension rope, and the raised angle, such that the radial swing angle and the rotational swing angle at the target position are smaller than a predetermined threshold angle and the time it takes for the suspension load to reach the target position is minimized.The command signal generation unit generates and outputs the angular velocity command signal corresponding to the angular velocity set by the speed setting unit.

[0008] According to this configuration, the speed setting unit can set the angular velocity of the upper body based on the equation of motion of the suspended load, such that the swing angle of the suspended load at the target position is smaller than the threshold angle and the time it takes for the suspended load to reach the target position is minimized. In particular, since the trajectory of the slewing angular velocity is set to include multiple curved trajectories in both the acceleration and deceleration zones, the suspended load can be moved with the minimum possible travel time while suppressing the swing at the target position.

[0009] In the above configuration, the curved trajectory may be composed of trigonometric function curves.

[0010] With this configuration, the forces acting on the suspended load (inertial force, centrifugal force, and Coriolis force) can be stably controlled by each process on the trigonometric function curve.

[0011] In the above configuration, the command signal generation unit may also input the generated angular velocity command signal to the slewing drive unit.

[0012] According to this configuration, the upper body can be automatically rotated based on the angular velocity command signal generated by the command signal generation unit, so as to move the suspended load to the target position while suppressing load swing at the target position.

[0013] In the above configuration, the speed setting unit may further set the rotational angular velocity of the upper body such that, during the rotational operation, the rotational angular velocity of the upper body becomes smaller than a preset maximum rotational angular velocity.

[0014] In the above configuration, the speed setting unit may further set the angular velocity of the upper body such that the rotational angular acceleration of the upper body during the rotational operation is less than a preset maximum rotational angular acceleration.

[0015] In the above configuration, the speed setting unit may set the angular velocity based on the following Equation I and Equation II as the motion equation of the suspended load. ml 2 (1 + θ1 2 )θ1’’ + ml 2 θ1θ2θ2’’ + mlL(cosθ3 - θ1sinθ3)θ3’’ - ml 2 θ2θ4’’ + ml 2 θ1(θ1’ 2 + θ2’ 2 ) - mLl(sinθ3 + θ1cosθ3)θ3’ 2 - ml(lθ1 + Lsinθ3)θ4’ 2 - 2ml 2 θ2’θ4’ + mglθ1 + 2mlθ1’l’(1 + θ1 2 ) - mθ1l’ 2 - mLθ1θ3’l’sinθ3 + 2mlθ1θ2θ2’l’ = 0 ···(Equation I) ml 2 θ1θ2θ1’’ + ml 2 (1 + θ2 2 )θ2’’ + mlLθ2sinθ3θ3’’ + ml(Lsinθ3 + lθ1)θ4’’ + ml 2 θ2(θ1’ 2 + θ2’ 2 ) - mLlθ2cosθ3θ3’ 2 - ml 2 θ2θ4’ 2 + 2mLlθ3’θ4’cosθ3 + 2ml 2 θ1’θ4’ + mglθ2 + 2mlθ1θ4’l’ - mLθ2θ3’l’sinθ3 + 2mlθ2’l’(1 + θ2 2 ) - mθ2l’ 2 + 2mlθ1θ2θ1’l’ = 0 ···(Equation II) (wherein θ1: radial swing angle of the suspended load, θ2: slewing swing angle of the suspended load, θ1': radial swing angular velocity of the suspended load, θ2': slewing swing angular velocity of the suspended load, θ1'': radial swing angular acceleration of the suspended load, θ2'': slewing swing angular acceleration of the suspended load, θ3: elevation angle of the upright body with respect to the vertical direction, θ3': rate of change of the elevation angle, θ3'': acceleration of the elevation angle, θ4: slewing angle of the upper body, θ4': slewing angular velocity of the upper body, θ4'': slewing angular acceleration of the upper body, g: acceleration due to gravity, L: length of the upright body, l: length of the suspension rope from the tip of the upright body to the suspended load, l': rate of change of the length of the suspension rope, m: mass of the suspended load)

[0016] In the above configuration, the speed setting unit may set the angular velocity of the upper body to reach the target position to include a two-stage curved trajectory in both the acceleration and deceleration regions.

[0017] Furthermore, in the above configuration, the speed setting unit may set the angular velocity of the upper body up to the target position to include three curved trajectories in both the acceleration and deceleration regions.

[0018] In the above configuration, the speed setting unit may further set the speed of rotation of the undulating body such that, in the acceleration region of the angular velocity of the upper body, the undulating body rotates in the upright direction, and in the deceleration region, the undulating body rotates in the downward direction.

[0019] In the above configuration, the speed setting unit may further set the speed of winding up and winding down the load rope so that the load is raised in the acceleration region of the angular velocity of the upper body and lowered in the deceleration region.

[0020] In the above configuration, the speed setting unit may set the speed for the rotation of the luffing body such that in the acceleration region of the angular velocity of the upper body, the luffing body rotates in the upright direction, and in the deceleration region, the luffing body rotates in the downward direction, and set the speed for the hoisting and lowering of the load rope such that in the acceleration region of the angular velocity of the upper body, the suspended load is raised, and in the deceleration region, the suspended load is lowered. [Effects of the Invention]

[0021] According to the present invention, a work machine is provided that can efficiently move a suspended load to a target position and suppress load swing at the target position. [Brief explanation of the drawing]

[0022] [Figure 1] This is a side view of a work machine relating to one embodiment of the present invention. [Figure 2] This is a schematic perspective view illustrating the rotation control of a work machine according to one embodiment of the present invention. [Figure 3] This is a block diagram of a work machine relating to one embodiment of the present invention. [Figure 4] This is a flowchart of the rotation control of a work machine according to one embodiment of the present invention. [Figure 5] This is a perspective view of an experimental apparatus simulating a work machine according to one embodiment of the present invention. [Figure 6] This is a block diagram of an experimental apparatus assuming a work machine according to one embodiment of the present invention. [Figure 7] This is another slewing speed profile, which is compared with the slewing speed profile of the upper body according to one embodiment of the present invention, and is an example of a profile used in the verification experiment. [Figure 8] This is another slewing speed profile, which is compared with the slewing speed profile of the upper body according to one embodiment of the present invention, and is an example of a profile used in the verification experiment. [Figure 9A] This graph shows the time progression of the turning angle in the verification experiment of the present invention. [Figure 9B] This graph shows the time course of the turning angular velocity in the verification experiment of the present invention. [Figure 9C] This graph shows the time course of rotational angular acceleration in the verification experiment of the present invention. [Figure 9D] This graph shows the time course of the suspended load swing in the verification experiment of the present invention. [Figure 10A] This graph shows the time progression of the turning angle in the verification experiment of the present invention. [Figure 10B] This graph shows the time course of the turning angular velocity in the verification experiment of the present invention. [Figure 10C] This graph shows the time course of rotational angular acceleration in the verification experiment of the present invention. [Figure 10D] This graph shows the time course of the suspended load swing in the verification experiment of the present invention. [Figure 11] This is an example of the rotational speed profile of the upper body in an embodiment of the present invention. [Figure 12] This is an example of the rotational speed profile of the upper body in an embodiment of the present invention. [Figure 13A] This graph shows the time progression of the rotation angle in an embodiment of the present invention. [Figure 13B] This graph shows the time course of the turning angular velocity in an embodiment of the present invention. [Figure 13C] This graph shows the time course of angular acceleration in an embodiment of the present invention. [Figure 13D] This graph shows the time progression of the suspended load swing in an embodiment of the present invention. [Figure 14A] This graph shows the time progression of the rotation angle in an embodiment of the present invention. [Figure 14B] This graph shows the time course of the turning angular velocity in an embodiment of the present invention. [Figure 14C] This graph shows the time course of rotational angular acceleration in an embodiment of the present invention. [Figure 14D] This graph shows the time progression of the suspended load swing in an embodiment of the present invention. [Figure 15A]This graph shows the time progression of the rotation angle in an embodiment of the present invention. [Figure 15B] This graph shows the time course of the turning angular velocity in an embodiment of the present invention. [Figure 15C] This graph shows the time course of rotational angular acceleration in an embodiment of the present invention. [Figure 15D] This graph shows the time progression of the suspended load swing in an embodiment of the present invention. [Figure 16A] This graph shows the time progression of the rotation angle in an embodiment of the present invention. [Figure 16B] This graph shows the time course of the turning angular velocity in an embodiment of the present invention. [Figure 16C] This graph shows the time course of rotational angular acceleration in an embodiment of the present invention. [Figure 16D] This graph shows the time progression of the suspended load swing in an embodiment of the present invention. [Figure 17A] This graph shows the time progression of the rotation angle in an embodiment of the present invention. [Figure 17B] This graph shows the time course of the turning angular velocity in an embodiment of the present invention. [Figure 17C] This graph shows the time course of rotational angular acceleration in an embodiment of the present invention. [Figure 17D] This graph shows the time progression of the suspended load swing in an embodiment of the present invention. [Figure 18A] This graph shows the time progression of the rotation angle in an embodiment of the present invention. [Figure 18B] This graph shows the time course of the turning angular velocity in an embodiment of the present invention. [Figure 18C] This graph shows the time course of rotational angular acceleration in an embodiment of the present invention. [Figure 18D] This graph shows the time progression of the suspended load swing in an embodiment of the present invention. [Figure 19A] This graph shows the time progression of the rotation angle in an embodiment of the present invention. [Figure 19B] This graph shows the time course of the turning angular velocity in an embodiment of the present invention. [Figure 19C] This graph shows the time course of rotational angular acceleration in an embodiment of the present invention. [Figure 19D] This graph shows the time progression of the suspended load swing in an embodiment of the present invention. [Figure 20A] This graph shows the time progression of the rotation angle in an embodiment of the present invention. [Figure 20B] This graph shows the time course of the turning angular velocity in an embodiment of the present invention. [Figure 20C] This graph shows the time course of rotational angular acceleration in an embodiment of the present invention. [Figure 20D] This graph shows the time progression of the suspended load swing in an embodiment of the present invention. [Figure 21A] This graph shows the time progression of the rotation angle in an embodiment of the present invention. [Figure 21B] This graph shows the time course of the turning angular velocity in an embodiment of the present invention. [Figure 21C] This graph shows the time course of rotational angular acceleration in an embodiment of the present invention. [Figure 21D] This graph shows the time progression of the suspended load swing in an embodiment of the present invention. [Figure 22A] This graph shows the time progression of the rotation angle in an embodiment of the present invention. [Figure 22B] This graph shows the time course of the turning angular velocity in an embodiment of the present invention. [Figure 22C] This graph shows the time course of rotational angular acceleration in an embodiment of the present invention. [Figure 22D] This graph shows the time progression of the suspended load swing in an embodiment of the present invention. [Figure 23A] This graph shows the time evolution of the slewing angular velocity and the swing of the suspended load in an embodiment of the present invention. [Figure 23B] This graph shows the time evolution of the slewing angular velocity and the swing of the suspended load in an embodiment of the present invention. [Figure 24] This figure shows the placement of strain gauges on the lower boom in an embodiment of the present invention. [Figure 25] This graph shows the time evolution of measured stress, load swing, and slewing angle in an embodiment of the present invention. [Figure 26] This figure shows an overview of a dynamic simulation model in an embodiment of the present invention, and is a perspective view of a crane model. [Figure 27] This figure shows an overview of a dynamic simulation model in an embodiment of the present invention, and is a side view of a crane model. [Figure 28] This graph shows the time evolution of the turning angular velocity trajectory and turning angle as performed by a skilled operator in an embodiment of the present invention. [Figure 29] In an embodiment of the present invention, Figure 28 corresponds to a graph showing the time evolution of the measured stress, suspension load swing, and slewing angle. [Figure 30] This graph shows a portion of Figures 28 and 29 superimposed in an embodiment of the present invention. [Figure 31] A graph showing a typical input trajectory, as referenced in embodiments of the present invention, is a graph showing the time evolution of acceleration and velocity during turning. [Figure 32] This is a perspective view showing the stress evaluation area in the FEM simulation in an embodiment of the present invention. [Figure 33] This graph shows the simulation results for each operating condition in an embodiment of the present invention, and is a graph showing the time evolution of the generated stress. [Figure 34] This figure shows a three-stage S-shaped trajectory in an embodiment of the present invention, and is a graph showing the time evolution of the turning angular velocity. [Figure 35] This is a block diagram for generating the optimal trajectory in an embodiment of the present invention. [Figure 36A] This graph shows the time progression of the slewing angle, boom angle, and rope length in an embodiment of the present invention. [Figure 36B] This graph shows the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity in an embodiment of the present invention. [Figure 36C]This graph shows the time evolution of rotational angular acceleration, boom angular acceleration, and rope length acceleration in an embodiment of the present invention. [Figure 36D] This graph shows the time progression of the swing angle of a suspended load in an embodiment of the present invention. [Figure 37A] This graph shows the time progression of the slewing angle, boom angle, and rope length in an embodiment of the present invention. [Figure 37B] This graph shows the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity in an embodiment of the present invention. [Figure 37C] This graph shows the time evolution of rotational angular acceleration, boom angular acceleration, and rope length acceleration in an embodiment of the present invention. [Figure 37D] This graph shows the time progression of the swing angle of a suspended load in an embodiment of the present invention. [Figure 38A] This graph shows the time progression of the slewing angle, boom angle, and rope length in an embodiment of the present invention. [Figure 38B] This graph shows the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity in an embodiment of the present invention. [Figure 38C] This graph shows the time evolution of rotational angular acceleration, boom angular acceleration, and rope length acceleration in an embodiment of the present invention. [Figure 38D] This graph shows the time progression of the swing angle of a suspended load in an embodiment of the present invention. [Figure 39A] This graph shows the time progression of the slewing angle, boom angle, and rope length in an embodiment of the present invention. [Figure 39B] This graph shows the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity in an embodiment of the present invention. [Figure 39C] This graph shows the time evolution of rotational angular acceleration, boom angular acceleration, and rope length acceleration in an embodiment of the present invention. [Figure 39D] This graph shows the time progression of the swing angle of a suspended load in an embodiment of the present invention. [Figure 40]This graph shows the operating time and load swing amount (angle) under each condition: a three-stage S-shaped track, an STT track, and a skilled operator track, using the results for a two-stage S-shaped track as a baseline. [Figure 41] This graph shows the boom luffing angular velocity trajectory and rope vertical velocity trajectory proposed in this embodiment, along with the three-stage S-shaped trajectory of the slewing motion. [Figure 42] This is a plan view showing the boom tip trajectory of the proposed trajectory, which combines slewing and boom luffing movements. [Figure 43A] This graph shows the time progression of the slewing angle, boom angle, and rope length in an embodiment of the present invention. [Figure 43B] This graph shows the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity in an embodiment of the present invention. [Figure 43C] This graph shows the time evolution of rotational angular acceleration, boom angular acceleration, and rope length acceleration in an embodiment of the present invention. [Figure 43D] This graph shows the time progression of the swing angle of a suspended load in an embodiment of the present invention. [Figure 44A] This graph shows the time progression of the slewing angle, boom angle, and rope length in an embodiment of the present invention. [Figure 44B] This graph shows the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity in an embodiment of the present invention. [Figure 44C] This graph shows the time evolution of rotational angular acceleration, boom angular acceleration, and rope length acceleration in an embodiment of the present invention. [Figure 44D] This graph shows the time progression of the swing angle of a suspended load in an embodiment of the present invention. [Figure 45A] This graph shows the time progression of the slewing angle, boom angle, and rope length in an embodiment of the present invention. [Figure 45B] This graph shows the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity in an embodiment of the present invention. [Figure 45C] This graph shows the time evolution of rotational angular acceleration, boom angular acceleration, and rope length acceleration in an embodiment of the present invention. [Figure 45D] This graph shows the time progression of the swing angle of a suspended load in an embodiment of the present invention. [Figure 46A] This graph shows the time progression of the slewing angle, boom angle, and rope length in an embodiment of the present invention. [Figure 46B] This graph shows the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity in an embodiment of the present invention. [Figure 46C] This graph shows the time evolution of rotational angular acceleration, boom angular acceleration, and rope length acceleration in an embodiment of the present invention. [Figure 46D] This graph shows the time progression of the swing angle of a suspended load in an embodiment of the present invention. [Figure 47A] This graph shows the time progression of the slewing angle, boom angle, and rope length in an embodiment of the present invention. [Figure 47B] This graph shows the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity in an embodiment of the present invention. [Figure 47C] This graph shows the time evolution of rotational angular acceleration, boom angular acceleration, and rope length acceleration in an embodiment of the present invention. [Figure 47D] This graph shows the time progression of the swing angle of a suspended load in an embodiment of the present invention. [Figure 48A] This graph shows the time progression of the slewing angle, boom angle, and rope length in an embodiment of the present invention. [Figure 48B] This graph shows the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity in an embodiment of the present invention. [Figure 48C] This graph shows the time evolution of rotational angular acceleration, boom angular acceleration, and rope length acceleration in an embodiment of the present invention. [Figure 48D] This graph shows the time progression of the swing angle of a suspended load in an embodiment of the present invention. [Figure 49A] This graph shows the time progression of the slewing angle, boom angle, and rope length in an embodiment of the present invention. [Figure 49B]This graph shows the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity in an embodiment of the present invention. [Figure 49C] This graph shows the time evolution of rotational angular acceleration, boom angular acceleration, and rope length acceleration in an embodiment of the present invention. [Figure 49D] This graph shows the time progression of the swing angle of a suspended load in an embodiment of the present invention. [Figure 50A] This graph shows the relationship between the suspension load swing angle and stress amplitude in an embodiment of the present invention. [Figure 50B] This graph shows the relationship between the suspension load swing angle and stress amplitude in an embodiment of the present invention. [Figure 50C] This graph shows the relationship between the suspension load swing angle and stress amplitude in an embodiment of the present invention. [Figure 51] This graph compares the stresses applied to the lower booms of multiple tracks in an embodiment of the present invention. [Figure 52A] This figure shows the load profile of the assumed work in the fatigue evaluation method according to an embodiment of the present invention. [Figure 52B] This figure shows the load profile of the assumed work in the fatigue evaluation method according to an embodiment of the present invention. [Modes for carrying out the invention]

[0023] <First Embodiment> Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figure 1 is a side view of the crane 10 (an example of a work machine) according to this embodiment. Although Figure 1 shows the directions of "up," "down," "forward," and "rear," these directions are shown for convenience in explaining the structure of the crane 10 according to this embodiment and the rotation control described later, and do not limit the direction of movement or usage of the work machine according to the present invention.

[0024] The crane 10 comprises a traveling body 14 (lower body), a slewing body 12 (upper body) supported on the traveling body 14 so as to be able to rotatably around a pivot axis extending vertically, a boom 16 (luffing body), and a mast 20. A counterweight 13 for adjusting the balance of the crane 10 is mounted on the rear of the slewing body 12. A cab 15 is provided at the front end of the slewing body 12. The cab 15 corresponds to the operator's seat of the crane 10.

[0025] The boom 16 shown in Figure 1 is a so-called lattice type and consists of a lower boom 16A (base end of the luffing body), one or more (three in the illustrated example) intermediate booms 16B, 16C, and 16D, and an upper boom 16E (tip end of the luffing body opposite to the base end of the luffing body). Specifically, the lower boom 16A is supported at the front of the slewing body 12 so as to be able to rotate in the luffing direction around a horizontal rotation axis (first rotation axis). The intermediate booms 16B, 16C, and 16D are detachably added to the tip end of the lower boom 16A in that order. The upper boom 16E is detachably added to the tip end of the intermediate boom 16D. The lower boom 16A is rotatably supported on the slewing body 12 at a boom foot pin 16S provided at its lower end.

[0026] Furthermore, the boom 16 has idler sieves 34S and 36S. The idler sieves 34S and 36S are rotatably supported on the rear side of the lower boom 16A, respectively.

[0027] However, the specific structure of the boom is not limited in this invention. For example, the boom may have no intermediate members, or it may have a different number of intermediate members than described above. Furthermore, the boom may be composed of a single member.

[0028] The mast 20 has a base end and a pivot end, the base end of which is rotatably connected to the slewing body 12. The pivot axis of the mast 20 is parallel to the pivot axis of the boom 16 and is located immediately behind the pivot axis of the boom 16. In other words, the mast 20 is rotatable in the same direction as the luffing direction of the boom 16.

[0029] Furthermore, the crane 10 includes a pair of left and right boom backstops 23 and a pair of left and right boom guy lines 24.

[0030] A pair of left and right boom backstops 23 are provided on both the left and right sides of the lower boom 16A of the boom 16. These boom backstops 23 come into contact with the center of the slewing body 12 in the front-rear direction when the boom 16 reaches the upright position shown in Figure 1. This contact prevents the boom 16 from being blown backward by strong winds or the like.

[0031] A pair of boom guy lines 24 connect the rotating end of the mast 20 to the tip of the boom 16. This connection synchronizes the rotation of the mast 20 with the rotation of the boom 16.

[0032] Furthermore, the crane 10 is equipped with various winches. Specifically, the crane 10 is equipped with a boom luffing winch 30 for luffing the boom 16, and a main hoisting winch 34 and an auxiliary hoisting winch 36 for hoisting and lowering the suspended load. The crane 10 is also equipped with a boom luffing rope 38, a main hoisting rope 50 (suspending load rope) that hangs down from the tip of the boom 16 and is connected to the suspended load, and an auxiliary hoisting rope 60. In the crane 10 according to this embodiment, the main hoisting winch 34 and the auxiliary hoisting winch 36 are installed near the base end of the boom 16. The boom luffing winch 30 is also installed on the slewing body 12. The positions of these winches 30, 34, and 36 are not limited to those described above.

[0033] The boom luffing winch 30 winds in and unwinds the boom luffing rope 38. The boom luffing rope 38 is routed so that the mast 20 rotates as the winch winds in and unwinds. Specifically, the rotating end of the mast 20 and the rear end of the slewing body 12 are provided with sheave blocks 40 and 42, each having multiple sheaves arranged in the width direction, and the boom luffing rope 38 pulled out from the boom luffing winch 30 is stretched between the sheave blocks 40 and 42. Therefore, as the boom luffing winch 30 winds in and unwinds the boom luffing rope 38, the distance between the two sheave blocks 40 and 42 changes, causing the mast 20 and the boom 16, which is linked to it, to rotate in the luffing direction.

[0034] The main hoisting winch 34 raises and lowers the load using the main hoisting rope 50. The main hoisting rope 50 (load rope) hangs down from the tip of the boom 16 and is connected to the load. A main hoisting guide sheave 54 is positioned at the tip of the boom 16, and a main hoisting sheave block is provided adjacent to the main hoisting guide sheave 54, with multiple main hoisting point sheaves 56 arranged in the width direction. The main hoisting rope 50 pulled out from the main hoisting winch 34 is sequentially placed over the idler sheave 34S and the main hoisting guide sheave 54, and is also stretched between the main hoisting point sheave 56 of the sheave block and the sheave 58 of the sheave block provided on the main hook 57 for the load. Therefore, when the main hoisting winch 34 winds up or unwinds the main hoisting rope 50, the distance between the two sheaves 56 and 58 changes, causing the main hook 57, which is connected to the main hoisting rope 50 hanging down from the tip of the boom 16, to be raised or lowered. As a result, the suspended load can be raised or lowered.

[0035] Similarly, the auxiliary winch 36 raises and lowers the load using the auxiliary rope 60. For this auxiliary winding, an auxiliary guide sheave 64 is rotatably mounted coaxially with the main guide sheave 54, and an auxiliary point sheave (not shown) is rotatably mounted adjacent to the auxiliary guide sheave 64. The auxiliary rope 60 pulled out from the auxiliary winch 36 is sequentially placed over the idler sheave 36S and the auxiliary guide sheave 64, and is also suspended from the auxiliary point sheave. Therefore, when the auxiliary winch 36 winds in or unwinds the auxiliary rope 60, an auxiliary hook for lifting a load (not shown) connected to the end of the auxiliary rope 60 is raised or lowered.

[0036] Figure 2 is a schematic perspective view illustrating the slewing control of the crane 10 according to this embodiment. Figure 3 is a block diagram of the crane 10 according to this embodiment.

[0037] In Figure 2, the pivot axis of the slewing body 12 is defined as the Z-axis, and the X-axis and Y-axis are provided on the upper surface of the slewing body 12. Also, 'a' is the distance between the base end (rotation center) of the boom 16 and the pivot center of the slewing body 12, i.e., the boom offset distance. Note that the base end of the boom 16 may be located on the pivot axis of the slewing body 12. In Figure 2, L is the length of the boom 16, and 'l' (lowercase L) is the length of the main hoisting rope 50 hanging from the tip of the boom 16 to the suspended load LM (rope length). Furthermore, angles θ1 and θ2 indicate the load swing angle of the suspended load LM (main hook 57). Specifically, angle θ1 is the angle of the main hoisting rope 50 with respect to the vertical direction when the boom 16 is viewed along the rotation direction of the slewing body 12, and is called the radial swing angle θ1 (swing angle in the normal plane). On the other hand, angle θ2 is the angle of the main hoisting rope 50 relative to the vertical when the boom 16 is viewed along the radial direction of the slewing motion of the slewing body 12, and is referred to as the slewing direction swing angle θ2 (swing angle at the tangential plane). Depending on the swing motion of the suspended load LM, the radial swing angle θ1 and the slewing direction swing angle θ2 can take on negative values ​​as well as positive values.

[0038] Angle θ3 is the elevation angle of the boom 16 around the rotation center axis. In Figure 2, angle θ3 is defined with respect to the vertical direction, but it may also be defined with respect to the horizontal direction. Angle θ4 is the rotation angle of the slewing body 12 around the rotation center axis. When the slewing body 12 rotates in the rotation direction, angle θ4 changes. At this time, the boom 16 supported by the slewing body 12 also rotates in the same way, and a swing occurs in the suspended load LM (main hoisting rope 50).

[0039] Furthermore, in the coordinate system shown in Figure 2, the base of the boom 16 is the origin, the predetermined horizontal direction (for example, the forward direction of the traveling body 14, the forward direction of the rotating body 12 at the start of rotation) is the X-axis, the horizontal direction perpendicular to the X-axis is the Y-axis, and the directions perpendicular to the X-axis and Y-axis (vertical direction) are the Z-axis. Also, in Figure 2, the mass m of the suspended load LM is shown.

[0040] In this embodiment, as shown in Figure 2, when the suspended load LM hanging from the tip of the boom 16 (luffing body) is moved by the rotational movement of the slewing body 12 (change in rotation angle θ4), it is possible to move the suspended load LM to the target position as quickly as possible while suppressing the swing of the suspended load LM at the target position.

[0041] Referring to Figure 3, the crane 10 further comprises a control unit 70, a slewing drive unit 71, a boom drive unit 72, a winch drive unit 73, a slewing operation unit 74, a boom operation unit 75, a winch operation unit 76, an input unit 81 (movement information receiving unit), a slewing angle detection unit 82, a luffing angle detection unit 83, a rope length detection unit 84 (rope length information acquisition unit), a boom length acquisition unit 85 (luffing body length information acquisition unit), a suspended load detection unit 86, and a display unit 87.

[0042] The slewing drive unit 71 receives a predetermined angular velocity command signal and is capable of swiveling the slewing body 12 around the pivot axis at a speed (angular velocity) corresponding to the angular velocity command signal. Specifically, the slewing drive unit 71 generates a driving force that enables the slewing body 12 to slewing in a first slewing direction and in a second slewing direction opposite to the first slewing direction around the pivot axis. The slewing drive unit 71 includes a hydraulic slewing motor and control valve that slewing the slewing body 12 by receiving a supply of hydraulic fluid.

[0043] The boom drive unit 72 generates a driving force to rotate the boom luffing winch 30, enabling the boom 16 to rotate (luff) around the rotational axis. The boom drive unit 72 includes a hydraulic luffing motor and control valve that rotate the boom luffing winch 30 by receiving a supply of hydraulic fluid.

[0044] The winch drive unit 73 generates the driving force to rotate the main hoisting winch 34, and by winding and unwinding the main hoisting rope 50 using the main hoisting winch 34, the suspended load LM can be raised and lowered relative to the ground. The winch drive unit 73 includes a hydraulic load motor and control valve that rotate the main hoisting winch 34 when supplied with hydraulic fluid. A similar winch drive unit (not shown) for rotating the auxiliary hoisting winch 36 is also provided.

[0045] The slewing control unit 74, the boom control unit 75, and the winch control unit 76 are located inside the cab 15 and receive operations from the operator to drive each component of the crane 10. Each control unit has, for example, a tiltable lever structure.

[0046] The slewing operation unit 74 receives operations for driving the slewing body 12 to rotate using the slewing drive unit 71. The slewing operation unit 74 is switchable between a slewing position for rotating the slewing body 12 in the first and second slewing directions, respectively, and a neutral position for stopping the rotation of the slewing body 12.

[0047] The boom control unit 75 receives commands from the boom drive unit 72 to raise and lower the boom 16. The boom control unit 75 is switchable between a luffing position for raising and lowering the boom 16 and a neutral position for stopping the luffing of the boom 16. In the luffing position, it is possible to operate the boom 16 in the raising direction to raise it and in the lowering direction to lower the boom 16.

[0048] The winch operating unit 76 receives commands from the winch drive unit 73 to raise and lower the suspended load LM. The winch operating unit 76 is switchable between a lifting position for raising and lowering the suspended load LM and a neutral position for stopping the lifting and lowering of the suspended load LM. In the lifting position, it is possible to operate the suspended load LM in the upward direction to raise it and in the downward direction to lower it.

[0049] The input unit 81 is located inside the cab 15 and receives input from the operator regarding the control of the crane 10. For example, the input unit 81 may include a touch panel input device, various switches, buttons, etc. The input unit 81 starts from the initial state in which the suspended load LM is lifted by the main hoisting rope 50 and sets a target slewing angle θ to move the suspended load LM to a predetermined target position around the slewing center axis by the slewing motion of the slewing body 12. 4d We accept travel information that includes this information.

[0050] The slewing angle detection unit 82 detects and outputs the slewing angle θ4 of the slewing body 12 (boom 16) around its pivot axis. The slewing angle detection unit 82 includes a gyro sensor (IMU (Inertial Measurement Unit) sensor) and a calculation unit (not shown). The slewing angle detection unit 82 measures the slewing angular velocity θ4' of the slewing body 12 around its pivot axis using the gyro sensor, and the calculation unit converts the measured angular velocity into an angle by integrating it once with respect to time, outputting the angle as the slewing angle θ4. The structure of the slewing angle detection unit 82 is not limited to the above, and known angle meters, encoders, etc., may also be used. The slewing angular acceleration θ4'' can be obtained by differentiating the slewing angular velocity θ4' which changes with time.

[0051] The luffing angle detection unit 83 detects and outputs the luffing angle θ3 of the boom 16 around the rotation center axis. The luffing angle detection unit 83 consists of a tilt sensor and detects the relative angle of the boom 16 with respect to the vertical direction. The luffing angle detection unit 83 may also detect the relative angle with respect to other objects. For example, the luffing angle detection unit 83 may detect the angle of the boom 16 to the ground (relative angle with respect to the horizontal direction), subtract this angle from 90 degrees to calculate and output the above-mentioned luffing angle θ3. Alternatively, the luffing angle detection unit 83 may be a known angle meter or the like. The rate of change of the luffing angle θ3' and the acceleration of change of the luffing angle θ3'' can be obtained by taking the first and second derivatives of the luffing angle θ3, which changes over time.

[0052] The rope length detection unit 84 acquires and outputs rope length information, which is information corresponding to the length l (lowercase L) of the main winding rope 50 between the tip of the boom 16 and the suspended load LM. In this embodiment, the distance between the main winding point sheave 56 and the main hook 57 (sheave 58) at the tip of the boom 16 is detected as the rope length. The rope length detection unit 84 includes a rotation amount detection unit capable of detecting the amount of rotation of the main winding winch 34, and a winding layer detection unit that detects the number of winding layers of the main winding rope 50 on the outer surface of the main winding winch 34. The rope length detection unit 84 calculates and outputs the distance based on the winch diameter of the main winding winch 34, the amount of winch rotation detected by the rotation amount detection unit, the amount of main winding rope 50 unwound from the main winding winch 34 estimated from the winding layers of the main winding rope 50 detected by the winding layer detection unit, and the number of times the main winding rope 50 is multiplied between the main winding point sheave 56 and the sheave block of the sheave 58. The rate of change of the rope length l, which changes over time, can be obtained by differentiating the rope length l once.

[0053] The method for detecting the length l of the main hoisting rope 50 is not limited to the above-described embodiment. For example, the rope length may be detected by clamping the wire with a sheave (not shown) and measuring the rotation of the sheave with an encoder. Alternatively, the suspended load LM may be detected by measuring the area below the tip of the boom 16 (boom top) in real time using a 3D LiDAR, and the rope length may be determined by measuring the distance from the boom top to the suspended load LM. Furthermore, the rope length may be calculated by measuring the distance to the suspended load LM using a known stereo camera or sound waves. In this case, the reference point for distance measurement may be any part of the boom, such as the boom top, the crane body, or the ground other than the crane. In addition, the rope length may be calculated by attaching a position-measuring sensor such as a GPS to the suspended load LM or the main hook 57.

[0054] The boom length acquisition unit 85 acquires information regarding the length L of the boom 16 used in the slewing control of the slewing body 12 performed by the control unit 70. That is, the boom length acquisition unit 85 acquires and outputs information (luffing body length information) corresponding to the length of the boom 16 in the longitudinal direction of the boom (luffing body longitudinal direction), which is the direction connecting the base end (luffing body base end) and the tip end (luffing body tip) of the boom 16. The boom length acquisition unit 85 may be a storage unit that stores the length of the boom 16 when the crane 10 is manufactured, or it may be an input unit that receives information regarding the length of the boom 16 from the operator. For this reason, the function of the boom length acquisition unit 85 may be performed by the storage unit 704 or input unit 81 of the control unit 70 in Figure 3. Furthermore, when multiple booms 16 of different lengths are selectively attached to the slewing body 12, the boom length acquisition unit 85 may also be a receiving unit that receives information regarding the length of the boom 16 from RFID or the like attached to each boom 16.

[0055] The suspended load detection unit 86 acquires and outputs information (suspended load amount information) regarding the weight (mass m) of the suspended load LM connected to the main hook 57. In this embodiment, the suspended load detection unit 86 includes a load sensor (load cell) (not shown) connected to the main winding rope 50, and detects the weight of the suspended load LM based on the change in the strain of the tension of the main winding rope 50. In other embodiments, the pressure in the hydraulic circuit that raises and lowers the boom 16 may be detected by a pressure gauge (not shown), and the load of the suspended load LM may be estimated based on this pressure.

[0056] The display unit 87 is a display located inside the cab 15 and displays various information to inform the operator.

[0057] The control unit 70 consists of a CPU (Central Processing Unit), a ROM (Read Only Memory) for storing control programs, a RAM (Random Access Memory) used as a working area for the CPU, and the like. The control unit 70 functions by having the CPU execute the control program stored in the ROM, thereby comprising a drive control unit 701, a target speed calculation unit 702 (turning angular speed setting unit, speed setting unit), a command signal generation unit 703, and a storage unit 704.

[0058] The drive control unit 701 inputs command signals corresponding to the operating direction and amount of operation received by the slewing operation unit 74, boom operation unit 75, and winch operation unit 76 to the slewing drive unit 71, boom drive unit 72, and winch drive unit 73, respectively, and drives each drive unit.

[0059] The target speed calculation unit 702 sets the target speed (target angular velocity θ4') of the slewing body 12 until the suspended load LM reaches the target position when automatic slewing control is performed. Automatic slewing control is a control system for automatically moving the suspended load LM from a predetermined initial position to the target position in the slewing direction. In this case, the angular velocity set by the target speed calculation unit 702 takes precedence regardless of the amount of operation received by the operation unit. Similarly, the target speed calculation unit 702 controls the speed related to the change in the luffing angle of the boom 16 and the length of the main hoisting rope 50.

[0060] The command signal generation unit 703 generates and outputs an angular velocity command signal corresponding to the target velocity (angular velocity) set by the target velocity calculation unit 702. The angular velocity command signal output by the command signal generation unit 703 is input to the slewing drive unit 71. As a result, the slewing operation of the slewing body 12 is automatically controlled. In other embodiments, the angular velocity command signal may be input to and displayed on the display unit 87, and the operator may operate the slewing operation unit 74 according to the magnitude and direction of the angular velocity command signal (slewing assist). Similarly, the command signal generation unit 703 generates and outputs an angular velocity command signal corresponding to the target velocity set by the target velocity calculation unit 702, and inputs it to the boom drive unit 72 and the winch drive unit 73.

[0061] The memory unit 704 stores parameters, thresholds, and other information that are referenced during various control operations performed in the crane 10.

[0062] <Flow of turning control> Figure 4 is a flowchart of the slewing control of the crane 10 according to this embodiment. When the control unit 70 performs automatic control of the slewing motion, first the control unit 70 determines whether the automatic control switch included in the input unit 81 is ON or OFF (step S1). If the automatic control switch is ON (YES in step S1), the control unit 70 determines whether movement information is stored in the storage unit 704 (step S2). As described above, this movement information is the target slewing angle θ to the target position to which the suspended load LM is moved. 4d This includes the above, and is stored in the memory unit 704 when the operator inputs it through the input unit 81. However, the start conditions for turning control are not limited to those described above.

[0063] If movement information is available in step S2 (YES in step S2), the slewing angle detection unit 82, the elevation angle detection unit 83, and the rope length detection unit 84 detect the current slewing angle θ4, the elevation angle θ3, and the length l of the main winding rope 50, respectively (step S3). The detected information is stored in the storage unit 704. If the automatic control switch is OFF in step S1 (NO in step S1), or if there is no movement information in step S2 (NO in step S2), the processes in steps S1 and S2 of Figure 4 are repeated.

[0064] In step S3, once the information is detected, the boom length acquisition unit 85 acquires the length (L) of the boom 16. As mentioned above, the length of the boom 16 may be stored in the storage unit 704 beforehand, or it may be input through the input unit 81 or the like.

[0065] Next, the target velocity calculation unit 702 calculates the profile (transition, trajectory) of the slewing velocity (slewing angular velocity θ4') of the slewing body 12 as the suspended load LM moves from its initial position to the target position (step S5). In other words, in this embodiment, in order to suppress the swing of the suspended load LM, the angular velocity θ4' of the slewing body 12 is controlled to change according to the slewing angle θ4 (slewing position). In this explanation, the derivative of angle θ (angular velocity) is sometimes represented as θ', and the second derivative of θ (angular acceleration) is sometimes represented as θ''. Alternatively, the derivative may be represented by the number of dots placed above θ. These notation rules are the same for other variables. The calculated transition of the slewing angular velocity θ4' is displayed on the display unit 87 for the operator to check.

[0066] In step S5, once the velocity profile (the change in angular velocity θ4') is determined, in step S6, the target velocity calculation unit 702 calculates the estimated load swing amount of the suspended load LM at the target position. At this time, the radial swing angle θ1 and the slewing swing angle θ2 of the suspended load LM are calculated from the equations of motion, which will be described in detail later, and the results are displayed on the display unit 87. Note that the processing in step S6 is not mandatory.

[0067] Next, the command signal generation unit 703 generates a speed command signal (angular velocity command signal) corresponding to the calculated angular velocity θ4' (step S7) and inputs it to the slewing drive unit 71. As a result, the slewing drive unit 71 rotates the slewing body 12, and automatic control of the slewing motion of the slewing body 12 is performed (step S8). At this time, as will be shown later, the command signal generation unit 703 may also issue commands regarding the luffing of the boom 16 and the raising and lowering of the main hoisting rope 50.

[0068] <Regarding the calculation of turning speed> Next, we will describe in detail the calculation of the trajectory (profile) of the turning velocity (angular velocity θ4') performed in step S5 above.

[0069] As the slewing body 12 rotates toward the target position from the initial position where the suspended load LM is lifted by the boom 16, the suspended load LM connected to the main hoisting rope 50 experiences two-dimensional load swing in both the radial and slewing directions. Furthermore, as described later, if the boom 16 is raised or lowered, or if the length of the main hoisting rope 50 changes during the slewing motion, the load swing of the suspended load LM becomes more complex.

[0070] Therefore, in this embodiment, the control unit 70 determines the time-optimal trajectory for the slewing speed of the slewing body 12 and suppresses load swing at the target position. Furthermore, the trajectory referred to here includes not only the positional trajectory but also a temporal element, including the question of where the suspended load LM passes at each time. In addition, the control unit 70 ensures that the suspended load LM reaches the target position as quickly as possible and suppresses continuous load swing of the suspended load LM after it reaches the target position as much as possible.

[0071] The target velocity calculation unit 702 of the control unit 70 determines the change in the slewing angular velocity θ4' by the following calculation. First, the dynamics model of the crane 10 is derived according to Lagrange's equations of motion. At this time, the boom's luffing angular velocity θ3', the slewing angular velocity θ4' of the slewing body 12, and the rope hoisting (lowering) velocity l' are used as control inputs. In Figure 2, if the coordinates of the suspended load LM are (x, y, z), then the kinetic energy Tl This can be expressed as shown in equations 1 and 2.

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[0072] Furthermore, the potential energy U of the suspended load l This is expressed by Equation 3.

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[0073] <Verification experiment> Here, the inventors of the present invention compared the simulation results with experimental results using a lab-scale (1 / 12th the size of the actual machine) slewing crane 10M to confirm the validity of the dynamics derived above. Figure 5 is a perspective view of the lab-scale experimental apparatus assuming the crane 10 according to this embodiment. Figure 6 is a block diagram of the same experimental apparatus.

[0074] The lab-scale 10M crane is powered by three AC motors M1, M2, and M3 (Figure 6), which enable the slewing of the slewing body, the luffing of the 16M boom, and the hoisting and lowering of the 50M main hoisting rope. The behavior of the 16M boom and the suspended load LM is measured by a known motion capture system. For each operation of slewing of the slewing body, luffing of the 16M boom, and hoisting (lowering) of the 50M main hoisting rope, a pre-created time history profile of speed and angular velocity is converted into a current value signal, which is a speed command signal, and sent to a DSP (Digital Signal Processing). From the DSP, the speed command signal is sent in real time to the servo controller of each motor, and the device operates. Note that in Figure 6 and other references, boom luffing may be referred to as Boom hoist, slewing of the slewing body as Boom Rotation, and hoisting and lowering of the rope as Rope hoist.

[0075] To first confirm the validity of the dynamics, the inventors compared simulation results with experimental results (measurements) for the swing at the target position (residual load swing) under two conditions: a simple, arbitrary single-motion trajectory based on a cycloid curve, and a compound motion trajectory in which the slewing body, the elevation of the 16M boom, and the hoisting of the 50M main hoisting rope are performed simultaneously.

[0076] The following outlines the specifications of the experimental apparatus and the conditions for verifying its validity. Boom length L: 2.0 (m) The distance between the base end of the boom (center of rotation) and the center of rotation of the slewing body (boom offset distance) is a: -0.368 (m) Length of the main hoisting rope before the start of the turn: l: 2.0 (m) Mass of suspended load LM: 1.0 (kg) Target turning angle θ 4d :90 (degrees) Main winding rope winding distance l d :-1.0(m) Boom elevation angle θ3:60 (degrees) before rotation begins Boom elevation angle θ during rotation 3d -15°C

[0077] On the other hand, the specifications of the actual crane 10 at the work site are shown below as an example. Boom length L: 26 (m) The distance between the base end of the boom (center of rotation) and the center of rotation of the slewing body (boom offset distance) is a: 1.1 (m) Boom elevation angle: 35.0 degrees Main rope length l: 18.0 (m) Mass of hanging load LM: 3.0~4.0(T) Target turning angle θ 4d :120 (degrees) Working radius: 16.0(m)

[0078] Figure 7 shows another slewing speed profile for comparison with the slewing speed profile of the slewing body 12 according to this embodiment, and is an example of a profile used in the experiment (slewing speed (angular velocity) for single slewing motion). Figure 8 shows another slewing speed profile for comparison with the slewing speed profile of the upper body according to this embodiment, and is an example of a profile used in the experiment (slewing speed (angular velocity) for combined motion). In this case, the time for each section is t1=t2=t3=2.0 (sec). Note that in addition to the slewing speed profile, Figure 8 also shows the speed profiles related to the changes in boom elevation angle and rope length.

[0079] Figures 9A, 9B, 9C, and 9D are graphs showing the time evolution of the slewing angle (Figure 9A), slewing angular velocity (Figure 9B), slewing angular acceleration (Figure 9C), and suspended load swing angle (Figure 9D) in this verification experiment. Similarly, Figures 10A, 10B, 10C, and 10D are graphs showing the time evolution of the slewing angle (Figure 10A), slewing angular velocity (Figure 10B), slewing angular acceleration (Figure 10C), and suspended load swing (Figure 10D) in this verification experiment. Note that each figure in Figure 9 corresponds to the single slewing motion described above, and each figure in Figure 10 corresponds to the combined motion described above. In each figure, sim shows the simulation results, and exp shows the experimental results.

[0080] As shown in the graphs in Figure 9 and Figure 10, the simulation results and experimental results show good agreement for each characteristic of the swing of the suspended load LM that occurs in any given trajectory, under both single and combined slewing conditions. Therefore, this verification result confirms the validity of the crane load swing dynamics model constructed as described above.

[0081] <Regarding the two-stage S-shaped trajectory> The inventors have provided a two-stage S-shaped trajectory in the acceleration zone and the deceleration zone, and the target slewing angle θ of the crane 10. 4d To achieve this, we have discovered a control method that allows the turret to rotate in the shortest possible time and reach the target rotation angle, both in the case of a single rotation operation and in the case of a combined operation involving rotation, boom luffing, and main hoisting rope hoisting (lowering).

[0082] Figure 11 shows an example of a turning angular velocity trajectory, including a two-stage S-shaped trajectory in a single turning motion. The equation representing the trajectory in Figure 11 is shown in Equation 7, and the maximum turning angular velocity is shown in Equation 8. Note that the trajectory in Figure 11 is asymmetrical along the time axis, but the trajectory may also be symmetrical.

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[0083] Figure 12 shows an example of the trajectory of the swing angular velocity, including a two-stage S-shaped trajectory in a compound motion. Furthermore, Equation 9 shows the equation representing the trajectory of the boom luffing angular velocity θ3' in Figure 12, along with the maximum luffing angular velocity θ 3maxEquation 10 shows the '. Also, Equation 11 shows the equation representing the trajectory of the hoisting (lowering) speed l' of the main hoisting rope 50 (suspension rope), and the maximum hoisting (lowering) speed l max The expression is shown in Equation 12. Note that the target elevation angle is θ. 3d The target hoisting rope length is l d Furthermore, t h These are the times for each section shown in Figure 12. In the combined operation shown in Figure 12, the boom 16 is rotated in the upright direction during the slewing motion, and the main hoisting rope 50 is wound up.

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[0084] In this embodiment, considering applicability to the actual crane 10, the constraints in the simulation include not only the time intervals of the two-stage S-shaped trajectory and the residual swing angle after the slewing stops, but also the mechanical physical constraints of the crane 10, namely the maximum slewing angular velocity θ4' and the maximum slewing angular acceleration θ4''. The objective function is shown in Equation 13, and the constraints are shown in Equations 14 to 17. Note that the objective function and constraints are not limited to these.

[0085]

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[0086] As mentioned above, the dynamics (equations of motion) of the suspended load LM in the crane are shown in equations 5 and 6, and the two-stage S-shaped trajectory is shown in equation 7. In addition, the trajectory of the elevation angular velocity of the boom 16 and the trajectory of the hoisting speed of the main hoisting rope 50 are shown in equations 9 to 12.

[0087] Equation 15 above shows the allowable swing angle of the suspended load LM. Equation 16 shows the constraints on the slewing angular velocity θ4' on the machine, and Equation 17 shows the constraints on the slewing angular acceleration θ4'' on the machine. These constraints depend on the structure of the drive system, including the hydraulic circuit of the crane 10, and should therefore be set in advance according to the crane (working machine) in question.

[0088] Furthermore, although the above embodiment describes a configuration in which a two-stage S-shaped trajectory is set in the acceleration and deceleration zones of the turning motion, the present invention is not limited thereto. As will be described in detail later, a three-stage S-shaped trajectory or more stages of S-shaped trajectory may be set.

[0089] <Second Embodiment> Next, a second embodiment of the present invention will be described. This embodiment differs from the first embodiment described above in that it focuses on reducing the load on the boom 16 during rotation. Points that are the same as in the first embodiment will be omitted from the explanation, or will be explained by referencing part of the first embodiment.

[0090] In this embodiment, the target speed calculation unit 702 sets the speed for the rotation of the boom 16 such that the boom 16 rotates in the upright direction during the acceleration zone of the rotational angular velocity of the slewing body 12, and rotates in the lowering direction during the deceleration zone. The set speed is reflected in the command signal by the command signal generation unit 703 and input to the boom drive unit 72.

[0091] Furthermore, in this embodiment, the target speed calculation unit 702 sets the speed for raising and lowering the main winding rope 50 so that the suspended load LM is raised in the acceleration region of the slewing angular velocity of the slewing body 12, and the suspended load LM is lowered in the deceleration region. The set speed is reflected in the command signal by the command signal generation unit 703 and input to the winch drive unit 73.

[0092] In other words, in this embodiment, when the slewing motion of the slewing body 12 switches from the acceleration range to the deceleration range, the boom 16 rises to its highest position and then lowers back to its original elevation angle. Similarly, when the slewing motion of the slewing body 12 switches from the acceleration range to the deceleration range, the suspended load LM is positioned at its highest position and then lowers back to its original height.

[0093] With this configuration, it becomes possible to suppress the stress on the lower boom 16A of the boom 16 during the slewing motion, thereby extending the lifespan of the boom 16 and, consequently, the crane 10.

[0094] In addition, the luffing of the boom 16, the raising or lowering of the main hoisting rope 50, or one of these may be combined with the slewing motion. [Examples]

[0095] <First Example> Next, the effects of the two-stage S-shaped trajectory according to the first embodiment described above will be explained in detail using examples. However, the present invention is not limited to the following examples.

[0096] For the optimization calculations to find solutions that satisfy the above equations, a sequential quadratic programming method is used as an example. Here, the analysis conditions for single and combined rotational motions are shown as the following cases. (In the case of a single rotational movement) Case R1: Both turning angular velocity and turning angular acceleration are constrained, and the turn must be 90 degrees to reach the target turning angle. Case R2: Both turning angular velocity and turning angular acceleration are constrained, and the turn must be 120 degrees to reach the target turning angle. • Case R3: Both rotational angular velocity and rotational angular acceleration are constrained, the rope rotates 90 degrees to the target rotational angle, and the length of the main winding rope is half that of Case R1. Case R4: Constraints exist on rotational velocity, rotational acceleration, and load swing angle; the load must rotate 90 degrees to reach the target rotation angle. (In the case of combined actions) Case C1: Both rotational angular velocity and rotational angular acceleration are constrained, the turn must be 90 degrees to the target rotational angle, and rope winding operation is performed during the turn. Case C2: Both rotational angular velocity and rotational angular acceleration are constrained, the turn is 90 degrees to the target rotational angle, and the boom is erected during the turn. Case C3: Both rotational angular velocity and rotational angular acceleration are constrained, the turn is 90 degrees to the target rotational angle, and rope hoisting and boom erection operations occur during the turn.

[0097] Table 1 shows the experimental conditions for each analysis and experimental apparatus. [Table 1] Furthermore, the constraints in the analysis are shown in Table 2. [Table 2] As shown in Tables 1 and 2, in this embodiment, the constraints for angular velocity, angular acceleration, residual load swing, and time in each acceleration / deceleration section are set to common values ​​for all conditions. However, in case R4, stricter constraints are considered, and additional constraints are added so that the load swing angle during operation is half of the maximum swing angles in the circumferential and radial directions that occur in case R1. Furthermore, in the combined operating conditions of cases C1, C2, and C3, the time t in the acceleration / deceleration section during rope hoisting (lowering) and boom luffing operations is set. h Each of these is set to 2.0 sec, and the constant speed section is varied so that the sum of the acceleration / deceleration sections and the time of these sections is equal to the total rotation time T. In addition, in case C3, conditions are set with different patterns for rope hoisting / lowering and boom luffing (C3-1 to C3-4).

[0098] <Simulation results of single-motion turning> Figures 13 through 16 show the analysis results for cases R1, R2, R3, and R4. Figure 13A is a graph showing the time course of the slewing angle (θ4) in case R1. Figure 13B is a graph showing the time course of the slewing angular velocity (θ4') in case R1. Although Figure 13B also shows the boom luffing angular velocity and rope hoisting speed, these values ​​are not actively changed in a single slewing motion and can be ignored. Figure 13C is a graph showing the time course of the slewing angular acceleration (θ4'') in case R1. Figure 13D is a graph showing the time course of the suspended load swing in case R1. The technical significance of each graph is the same for Figures 14 through 16. The experimental results exp superimposed on each graph will be discussed later.

[0099] Furthermore, the upper section of Table 3 shows the time for each section of the turning trajectory, the total operating time, and the speed ratios r1 and r2 of the stepped portion of the two-stage S-shaped trajectory (the boundary between the first and second S-shapes) calculated under each condition of single-turn operation. These speed ratios are calculated by dividing the speed of the stepped portion by the maximum speed. r1 corresponds to the acceleration region, and r2 corresponds to the deceleration region. [Table 3]

[0100] (caseR1) According to the results for caseR1 shown in Figures 13A to 13D, the angular velocity trajectory generated by the optimization calculation (Figure 13B) exhibits a symmetrical shape around the halfway point of the operation time (central time). In the acceleration section t1 (see Figure 11) and the deceleration section t7, the angular acceleration reaches the limit value (Figure 13C), and in the constant speed section t4, the angular velocity also shows a speed close to the limit value (Figure 13B). The constant speed section t4 shows a value close to 0 (almost non-existent). At the point of maximum rotational speed, centrifugal force causes radial swing of the suspended load LM equivalent to that in the circumferential direction (Figure 13D). However, at the final target angle point, these two-dimensional load swings are sufficiently controlled.

[0101] (caseR2) As shown in Figures 14A to 14D, the results for caseR2, similar to caseR1, show a symmetrical shape around the halfway point of the operating time (Figure 14B). Angular acceleration reaches its limit in acceleration sections t1 and t3 (Figure 11) and deceleration sections t5 and t7 (Figure 14C), and angular velocity also reaches its limit in constant speed section t4 (Figure 14B). The constant speed section t4 at maximum speed is longer than in caseR1, and radial swing is also larger in this section (Figure 14D). However, the load swing in the two-dimensional direction is sufficiently controlled at the target angle point.

[0102] (caseR3) As shown in Figures 15A to 15D, the results for caseR3, similar to caseR1, show a symmetrical trajectory around the halfway point of the operation time (Figure 15B). Similar to caseR2, the angular acceleration reaches the limit in the acceleration sections t1 and t3 and the deceleration sections t5 and t7 (Figure 15C). On the other hand, the angular velocity does not reach the limit in the constant speed section t4, which shows the maximum speed (Figure 15B). Because the rope length is shorter than in caseR1, the load swing during operation oscillates with a smaller period than in caseR1 (Figure 15D). The load swing in the two-dimensional direction is controlled at the target angle point.

[0103] (caseR4) As shown in Figures 16A to 16D, the results for case R4, similar to case R1, show a symmetrical trajectory around the halfway point of the operation time (Figure 16B). Similar to case R1, the angular acceleration reaches the limit value in the acceleration section t1 and the deceleration section t7 (Figure 16C). Although the operation time is increased by approximately 14% compared to case R1, the amount of load swing during the turning motion is kept within the constraints (Figure 16D). Furthermore, the maximum angular velocity in the constant speed section t4 is also smaller than in case R1 (Figure 16B). In addition, load swing is sufficiently controlled at the target angle point (Figure 16D).

[0104] <Simulation results of combined actions> Similar to the previous figures, Figures 17 through 22 show the analysis results for cases C1, C2, and C3. Furthermore, the lower section of Table 3 shows the calculated rotational trajectory time intervals t1-t7, total operation time T, and speed ratios r1 and r2 for the stepped sections of the two-stage S-shaped trajectory under each condition of the combined operation. For case C3, the analysis results under conditions where the rope hoisting, lowering, and boom luffing patterns were varied are shown as C3-1 (Figure 19), C3-2 (Figure 20), C3-3 (Figure 21), and C3-4 (Figure 22). The other conditions are shown in Tables 1 and 2.

[0105] (Case C1) As shown in Figures 17A to 17D, the results for case C1 show that the acceleration and deceleration phases of the rotation speed (angular velocity) differ in terms of the time of each phase and the speed ratio of the steps (Figure 17B). In other words, unlike the conditions for single rotation motion (cases R1, R2, R3, R4), it shows an asymmetrical trajectory centered around the halfway point of the motion time. Also, the time from the deceleration phase t5 to t7 is shorter than the time from the acceleration phase t1 to t3 (Figure 17B). In the acceleration phase t1 and the deceleration phase t7, the angular acceleration is approximately at the upper limit of the limit. At the target angle point, the rope length is wound up to half of what it was at the start of the rotation, and the load swing in the two-dimensional direction is sufficiently damped (Figure 17D).

[0106] (Case C2) As shown in Figures 18A to 18D, the results for case C2 show that the acceleration and deceleration sections of the slewing speed differ in terms of the time of each section and the speed ratio of the sections. Here too, unlike the conditions for a single slewing motion, an asymmetrical trajectory is observed, although the degree of asymmetry and the amount of change are smaller compared to case C1. In addition, unlike the other conditions, the suspended load LM swings radially due to the effect of the boom's luffing motion immediately after the start of the slewing (Figure 18D). However, at the target angle point after the end of the motion, the boom luffing angle changes to the target angle, and the load swing in the two-dimensional direction is sufficiently controlled (Figure 18D).

[0107] (case C3) The results for cases C3-1, C3-2, C3-3, and C3-4, shown in Figures 19A to 22D, show that, similar to cases C1 and C2, the acceleration and deceleration sections differ in terms of time and speed ratio of the steps, resulting in an asymmetrical trajectory. Furthermore, comparing Figures 19, 20, 21, and 22 reveals that the rotation speed trajectory obtained by the optimization calculation differs depending on the conditions as the boom luffing trajectory and rope hoisting (lowering) trajectory patterns change. However, under all conditions, the residual load swing in the two-dimensional direction after the end of the operation is sufficiently damped (Figures 19D, 20D, 21D, and 22D).

[0108] Furthermore, under conditions where the rope length change and boom luffing change are symmetrical (case C3-1 and case C3-4, case C3-2 and case C3-3), the angular velocity profile shows a symmetrical shape in the time axis direction, and the load swing characteristics similarly show symmetrical results.

[0109] As described above, in the single turning motions from case R1 to R4, the turning speeds, including the two-stage S-shaped trajectory obtained by the optimization calculation, show a roughly symmetrical profile with respect to the time at half the total operating time.

[0110] In particular, the circumferential swing of the suspended load LM shows approximately the same amplitude but opposite signs at the end of the rotational acceleration (end of t3) and the start of rotational deceleration (start of t5), indicating that the circumferential load swing velocity is approximately the same at these times. Similarly, the radial swing of the suspended load LM shows approximately the same amplitude at the end of the rotational acceleration (end of t3) and the start of rotational deceleration (start of t5), indicating that the radial load swing velocity is the same but in opposite directions.

[0111] Figures 23A and 23B show superimposed graphs of the slewing speed and the swing angle of the suspended load LM during slewing for cases R1 and R4, respectively. It can be confirmed that the slewing control of the present invention, based on a two-stage S-shaped trajectory, is effective in damping the vibration problem of residual load swing. Furthermore, it has been confirmed that the two-stage S-shaped trajectory according to the present invention can achieve slewing in the shortest time while changing the speed ratio of each acceleration / deceleration section and stage, even when pre-set constraints are imposed on angular velocity, angular acceleration, load swing angle, etc.

[0112] Furthermore, the trajectories obtained for the slewing speed in cases C1, C2, and C3 show asymmetrical trajectories, with the time of each section and the speed ratio of the sections differing from those in the case of a single slewing motion. This is thought to be because changes in rope length and luffing angle affect the swing period of the suspended load LM and the inertial and centrifugal forces generated during the motion. In the conditions where the rope is raised (lowered), as in cases C1 and C3, the rope length changes over time, so the swing period also changes, and the time required for the acceleration or deceleration section tends to change accordingly. Also, in the conditions where the boom is luffed, as in cases C2 and C3, the boom luffing motion greatly affects the radial inertial force of the suspended load, so a large radial swing occurs at an earlier stage compared to the condition where the boom luffing angle does not change. However, by using an optimal slewing speed trajectory that also takes into account the radial dynamics of the suspended load LM due to the luffing motion, it is possible to suppress the two-dimensional load swing. Furthermore, these results confirm the effectiveness of the present invention, as it is possible to dampen vibrations at a target point at high speed not only in single-motion slewing but also in complex motions including rope hoisting and boom luffing by using the crane dynamics model and optimization method constructed in this invention.

[0113] <Laboratory-scale experimental results> Using the aforementioned 10M crane experimental setup (Figure 5), the effectiveness of the speed trajectories for each operation obtained by the optimization calculation described above in controlling load swing was confirmed. The experimental conditions were set in the same way as above in order to compare with the simulation results. For each condition, speed command signals based on the trajectories of the slewing angular velocity, rope hoisting speed, and boom luffing angular velocity, which were optimized in the simulation results, were input in real time from the DSP to each servo controller.

[0114] In the graphs from group 13 to group 22, the time evolution of the measured values ​​for slewing angle, slewing angular velocity, slewing angular acceleration, and load swing in the circumferential and radial directions is shown using exp data. As shown in each figure, the experimental results show that the input trajectories obtained by optimization calculations are roughly reproduced for the slewing angular velocity, rope hoisting speed, and boom luffing angular velocity. Furthermore, the characteristics of the load swing occurring two-dimensionally under all conditions roughly match the simulation results, and residual load swing is sufficiently suppressed at the target angle.

[0115] Furthermore, the slightly smaller load swing during the experiment compared to the simulation results is thought to be due to the influence of damping forces such as friction generated by the structure of the device. The slight differences in the degree and phase of residual load swing compared to the simulation are presumed to be due to the same reason. However, even in the experimental results of case C2, which showed a relatively large residual load swing, the load swing was only about 10 mm (circumferential direction) for a rope length of 1000 mm, which is sufficiently small, and it can be said that residual load swing was suppressed.

[0116] The experimental results described above confirmed that, even in actual machines, the two-stage S-shaped trajectory-based turning control is effective in suppressing residual load swing, even when constraints are placed on maximum angular velocity, angular acceleration, and load swing during turning. In this process, considering the mechanical and physical constraints of the work machine, such as maximum turning angular velocity and maximum turning angular acceleration, we were able to find a pattern trajectory that allows for operation in the shortest possible time for efficient work.

[0117] As described above, in the above embodiment (example), the target velocity calculation unit 702 calculates the target velocity (angular velocity θ4') of the slewing body 12 based on the equation of motion of the suspended load LM based on dynamics. The equation of motion includes at least the length L of the boom 16, the length l of the main hoisting rope 50, and the luffing angle θ3, and includes equations for the slewing direction and the radial direction, respectively. Based on these equations and predetermined constraints set as necessary, the target velocity calculation unit 702 sets the target velocity (angular velocity θ4') according to the elapsed time t of the slewing body 12 to reach the target position, such that the radial swing angle θ1 and the slewing direction swing angle θ2 at the target position are smaller than predetermined threshold angles, and the total slewing time T (arrival time) of the suspended load LM to the target position is minimized.

[0118] In this process, the target velocity calculation unit 702 sets a velocity profile that includes a two-stage S-shaped trajectory in both the acceleration and deceleration regions. Such a two-stage S-shaped trajectory can have the following effects. • The first stage of acceleration can be used to intentionally generate a slight load swing. The second stage of acceleration allows the vehicle to turn while suppressing the load's swing in accordance with the load's movement. • It is possible to apply a constant centrifugal force in the constant-speed section while timing vibration damping. • The second stage of deceleration reduces centrifugal force, thereby suppressing radial load sway. • The first stage of deceleration helps to suppress the remaining tangential load swing. Through the effects of each process described above, the forces acting on the crane 10 (inertial force, centrifugal force, and Coriolis force) can be controlled.

[0119] Furthermore, in the above embodiment, the target speed calculation unit 702 can set the target speed of the slewing body 12 based on the equation of motion of the suspended load LM, such that the swing angles θ1 and θ2 of the suspended load LM in two directions at the target position are smaller than a predetermined threshold angle and the arrival time of the suspended load LM is minimized. As a result, the suspended load LM can be moved with the minimum possible travel time while suppressing the swing of the load at the target position.

[0120] Furthermore, in the above embodiment, the target speed (change in angular velocity) of the slewing body 12 can be optimized so as to minimize the arrival time of the suspended load LM. In this case, the conditions for optimizing this problem include constraints on the swing of the suspended load LM.

[0121] Furthermore, in this embodiment, the calculation performed by the target velocity calculation unit 702 uses the equation of motion of the suspended load LM, which includes the length of the main hoisting rope 50 (position of the main hook 57), the elevation angle θ3 of the boom 16, and the length L of the boom 16 (slewing radius). Therefore, the suspended load LM can be moved to the target position in a short time while suppressing the swing of the suspended load LM with high precision.

[0122] <Second Example> Next, the second embodiment described above will be explained in detail using examples. Note that the present invention is not limited to the following embodiments. In this embodiment, first, the dynamic stress characteristics generated in the boom 16, which is the main structure of the crane 10, during the rotational movement of the crane 10 were confirmed by actual machine experiments. Table 4 shows the basic specifications of the actual crane. Here, θ 4d This indicates the target turning angle.

[0123] [Table 4]

[0124] In this experiment, a skilled operator controlled the crane 10 to perform high-speed slewing and load swing control. The dynamic characteristics of the crane 10's slewing angular velocity and slewing angle were measured by a rotary encoder attached to a slewing bearing (not shown) located between the slewing body 12 and the traveling body 14. The swing (angle and position) of the suspended load during the operation of the crane 10 was determined by analyzing the video from a load monitoring camera located at the tip of the boom 16. The target of stress measurement was the lower boom 16A of the boom 16, where high stress occurs. Strain gauges were attached to parts where no specific stress, such as stress concentration, occurred, and the dynamic stress during the operation of the crane 10 was measured. Figure 24 shows the positions of the strain gauges attached to the lower boom 16A. The upper part of Figure 24 is a front view of the lower boom 16A, and the lower part is a side view thereof. Figure 25 is a graph showing the time changes of the measured stress, load swing, and slewing angle.

[0125] As shown in Figure 25, the measurement results revealed that the stress generated in the lower boom 16A fluctuates in sync with the tangential sway of the suspended load, and that the maximum stress occurs when the sway of the suspended load is at its maximum. This confirmed that the stress experienced by the lower boom 16A during the slewing motion is mainly due to fluctuations in bending stress caused by the sway of the suspended load.

[0126] In this embodiment, a Finite Element Method (FEM) simulation model was constructed to evaluate the effectiveness of vibration damping and stress reduction due to the trajectory of the suspended load, which will be described in detail later. Figures 26 and 27 show an overview of the dynamic simulation model in this embodiment. Figure 26 is a perspective view of the crane 10 model, and Figure 27 is a side view of the crane 10 model. In this simulation model, the boom 16 and the main hoisting rope 50 are modeled as elastic bodies, while the slewing body 12 and the mast 20 (or gantry) are modeled as rigid bodies. The model of the main hoisting rope 50 is divided into elements to represent its actual flexible deformation characteristics. The suspended load LM (Figure 2) is treated as a point mass, with mass assigned to the nodes at the ends of the rope elements. The luffing motion of the boom 16 and the up-and-down motion of the main hoisting rope 50 reproduce the mechanisms of the sheaves and winches, just like in the actual machine.

[0127] In this simulation model, the boom 16, mast 20 (or gantry), boom guy lines 24, and various ropes are modeled as elastic bodies using beam elements, while the slewing body 12 and various sheaves are treated as rigid bodies. The boom 16 is represented by placing nodes at the intersections of each grid and connecting them with beam elements. The cross-sectional and material properties of the boom guy lines 24 and other elements are defined based on the specifications of the actual machine. Rope elements are discretized in detail to represent the flexibility of the rope, and appropriate physical properties such as bending, torsion, and axial elongation are assigned depending on the type of rope. The lower end of the boom 16 is connected to the slewing body 12 with a pin, allowing for luffing. The slewing motion of the slewing body 12 is achieved by applying angular velocity to nodes on the slewing axis constrained to the slewing body 12. The luffing and hoisting motions are modeled by simulating the winding motion of the rope, and the length of the rope is adjusted accordingly. Each sheave is discretized using solid elements, defining contact conditions between the rope and the sheave, and replicating the actual motion of the rope as it moves through the sheave. Furthermore, translational constraints are imposed between the tip node of the boom luffing rope 38 and the end node of the boom guyline 24. The load is modeled as a point mass, with the mass assigned to the node at the end of the rope element.

[0128] To verify the validity of the dynamic simulation model, the slewing angular velocity trajectory for a portion of the reciprocating operation section of the crane 10, obtained from actual machine experiments, was used as input, and the tangential load swing and the stress generated in the lower boom 16A were analyzed. Figure 28 is a graph showing the time evolution of the slewing angular velocity trajectory and slewing angle under the operation of a skilled operator. Figure 29 is a graph showing the time evolution of the measured stress and the swing of the suspended load, corresponding to Figure 28. Figure 30 is a graph showing parts of Figures 28 and 29 superimposed.

[0129] Referring to Figures 28 to 30, it was confirmed that the load swing and stress fluctuations obtained in the simulation above showed similar trends to those observed in the actual machine experiment. In particular, the stress on the lower boom 16A fluctuated according to the load swing behavior and was consistent with the trends observed in the actual machine experiment. This result confirmed the validity of the constructed dynamic simulation model.

[0130] Next, the effects of the axial motion of the crane 10 (slewing, elevation of boom 16, rope hoisting), as well as the oscillations of radial and tangential loads, on the stress generated in the lower boom 16A were analyzed using FEM. Figure 31 is a graph showing a typical input trajectory, illustrating the time evolution of acceleration and velocity during slewing. 'a' is acceleration and 'v' is velocity. Table 5 summarizes the analysis conditions and input parameters.

[0131] [Table 5]

[0132] In cases 1 to 3 of Table 5, the slewing, boom luffing, and rope hoisting operations are performed individually based on the trajectory shown in Figure 31. The acceleration and deceleration phases are defined using the maximum acceleration value determined according to the mechanical performance of the crane 10. As an example, the durations t1, t2, and t3 (Figure 31) of each operation are set to 3 seconds. In cases 4 and 5, the crane 10 remains stationary, and a sway as an initial input is applied to the suspended load LM in the radial and slewing (tangential) directions, respectively. Figure 32 is a perspective view showing the stress evaluation point SEP of the lower boom 16A in the FEM simulation. This point is reproduced using a beam element model of the cross-section of the lower boom 16A.

[0133] Figure 33 is a graph showing the simulation results for each operating condition shown in Table 5, illustrating the time evolution of the generated stress. The vertical axis of the graph represents the normalized stress, shown as a ratio to the maximum stress value observed in Case 1, which showed the highest stress among all conditions. Initial static stress generated by a pre-set load is offset to ensure a fair comparison, and only stress fluctuations arising from dynamic motion are considered. As a result, it was found that large stress fluctuations occur under conditions involving horizontal motion, particularly slewing (Case 1) and tangential load oscillation (Case 5). In contrast, the other cases showed minimal fluctuations. In both Case 1 and Case 5, the stress response exhibited vibrational behavior, and the vibrations of the boom 16 and the load coincided, as confirmed by FEM analysis. These results indicate that the structure of the crane 10 influences the stress response of the lower boom 16A and the oscillation of the load during horizontal motion (slewing). The boom 16 is pinned to the slewing body 12, allowing for luffing motion and making it less susceptible to the effects of moment generation in the luffing direction. In contrast, horizontal motion generates structural moments, approximating the behavior of a fixed-end cantilever, i.e., a structure (beam) with one end fixed and the other free. Therefore, the influence of horizontal motion on structural stress is more significant. Based on these results, this embodiment focuses on horizontal mechanical characteristics such as boom rotation (slewing) and tangential load oscillation, and provides a suspended load trajectory aimed at reducing structural stress.

[0134] From the results above, it is necessary to suppress the tangential swing of the suspended load in order to reduce the amount of damage to the crane 10 (machine). In this embodiment, an optimal trajectory for suppressing the tangential swing of the suspended load is proposed. This trajectory includes the two-stage S-shaped trajectory described in the first embodiment above, and further includes a three-stage S-shaped trajectory with additional S-shaped trajectories in the acceleration and deceleration stages. Furthermore, in order to efficiently transport the crane 10, an STT trajectory (Straight Transfer Transformation, STT) that adds the luffing motion of the boom 16 to the slewing motion was added, and the effect of these trajectories on the tangential swing of the suspended load was confirmed.

[0135] The STT trajectory described above simultaneously controls the slewing motion of the crane and the luffing motion of the boom, moving the projected trajectory of the boom tip and the suspended load linearly in a plan view, i.e., on the XY plane. This method cancels out the effects of centrifugal force that normally occurs during slewing, enabling efficient transport of the suspended load LM over the shortest distance and suppression of load swing. In terms of control, it has fewer state variables compared to conventional models, reducing the computation time required for optimal control calculations and improving the practicality of the control. Furthermore, because it can take into account changes in rope length, it enables transport while maintaining a constant height of the suspended load and flexible control according to on-site requirements. For the implementation of the STT trajectory, refer to the following: "Minimum time control of loads in a linear transport method by simultaneous luffing, slewing, and hoisting of a slewing crane, Kazuhiko Terashima, Kenichi Yano, Kensuke Suzuki, Transactions of the Society of Instrument and Control Engineers, Vol. 3, No. 10, 70 / 79 (2004)", "Optimal Control of Rotary Crane Using the Straight Transfer Transformation Method to Eliminate Residual Vibration, Ying SHEN, Kazuhiko TERASHIMA and Ken'ichi YANO, Transactions of the Society of Instrument and Control Engineers, Vol. 39, No. 9, 817 / 826 (2003)", and "Modeling and optimal control of a rotary crane using the straight transfer transformation method, Kazuhiko Terashima, Ying Shena, Ken'ichi Yano, Control Engineering Practice 15 (2007) 1179-1192".

[0136] Here, in order to represent the trajectories of each condition, based on the three-stage S-shaped trajectory, constraint conditions are set for the time and the parameters of each stage of the S-shaped trajectory. FIG. 34 is a diagram showing the three-stage S-shaped trajectory and is a graph showing the transition of the turning angular velocity. Further, the following Equation 18 is an equation showing the three-stage S-shaped trajectory of FIG. 34, and Equation 19 is an equation representing the maximum turning angular velocity. Note that the method of labeling each symbol in FIG. 34 is the same as that in FIG. 11.

[0137]

Number

[0138]

Number

[0139] Furthermore, Equations 20 and 21 are calculation formulas for the boom elevation angle corresponding to the turning angle θ 3STT in the STT.

Number

Number

[0140] Table 6 shows the constraint conditions for each trajectory. Here, optimization calculations are carried out according to the purpose. That is, for each of the two-stage S-shaped trajectory, the three-stage S-shaped trajectory, the STT, and the trajectory when an expert operates (expert operator trajectory), the parameters in Table 6 are applied to FIG. 34. Note that, as shown in Table 6, in this example, only the STT includes the elevation operation of the boom 16.

[0141]

Table 6

[0142] In addition, Table 7 shows the objective functions for the optimization corresponding to the conditions in Table 6. [Table 7] Here, T represents the operation time, and θ2amp represents the maximum amplitude in the tangential direction of the suspended load. Regarding the objective functions, for the two-stage S-shaped trajectory and the skilled operator trajectory, the minimization of the time T is evaluated, and for the three-stage S-shaped trajectory and STT, the minimization of the maximum sway of the suspended load in the tangential direction, that is, the maximum amplitude θ2amp, is evaluated. The maximum amplitude of the suspended load and the operation time are compared based on the results of the two-stage S-shaped trajectory. The objective functions and constraint conditions in the optimization calculation are shown in Equations 22 to 28.

[0143] First, the objective function is expressed by Equation 22 or Equation 23. [Equation] [Equation]

[0144] The constraint conditions are shown in the previous Equations 5 and 6 as the motion equations of the crane.

[0145] In addition, the time division and stage ratio of the three-stage S-shaped trajectory shown in Equation 7 can be expressed by the following Equation 24. [Equation]

[0146] In addition, the allowable value of the sway amount remaining at the target position is set by Equation 25. In Equation 25, the period Tp is defined by Equation 26. Also, in Equation 25, the maximum residual sway in the radial direction is θ 1rmax , and the maximum residual sway in the tangential direction is θ 2rmax is used. [Equation]

number

[0147] Furthermore, the permissible values ​​for angular velocity and angular acceleration are set by equations 27 and 28.

number

number

[0148] Table 8 shows the calculation and operating conditions, Table 9 shows the upper and lower limit constraints, and Table 10 shows the constraints for each inequality. In this calculation, the parameters and constraints for crane 10 were determined based on a lab-scale slewing crane (Figure 5) with a rope length ratio of approximately 1 / 9th that of the actual crane shown in Table 4. Furthermore, constraints are given so that residual load swing at the target point is sufficiently suppressed.

[0149] [Table 8]

[0150] [Table 9]

[0151] [Table 10]

[0152] Figure 35 shows a block diagram for generating the optimal trajectory. In this embodiment, in step S01, initial conditions for optimization are set. In step S02, the specifications of the optimization problem are set. At this time, the constraints include the aforementioned crane dynamics, speed, acceleration, time segment and stage ratio, and allowable load swing angle. Furthermore, in step S03, a trajectory is generated based on equation 18, and in step S04, the behavior of the suspended load is calculated based on equations 5 and 6. Then, in step S05, the objective function and constraints are evaluated based on equations 22 to 28. The optimization from steps S03 to S05 is repeated to determine the optimal trajectory.

[0153] Figure 36A is a graph showing the time evolution of the rotation angle, boom luffing angle, and rope length of a two-stage S-shaped trajectory, representing the optimization results in an embodiment of the present invention. Figure 36B is a graph showing the time evolution of the rotation angular velocity, boom angular velocity, and rope length velocity. Figure 36C is a graph showing the time evolution of the rotation angular acceleration, boom angular acceleration, and rope length acceleration. Figure 36D is a graph showing the time evolution of the suspended load swing angle.

[0154] Figure 37A is a graph showing the time course of the rotation angle, boom luffing angle, and rope length of a three-stage S-shaped trajectory, representing the optimization results in an embodiment of the present invention. Figure 37B is a graph showing the time course of the rotation angular velocity, boom angular velocity, and rope length velocity. Figure 37C is a graph showing the time course of the rotation angular acceleration, boom angular acceleration, and rope length acceleration. Figure 37D is a graph showing the time course of the suspended load swing angle.

[0155] Figure 38A is a graph showing the time course of the rotation angle, boom luffing angle, and rope length of the STT track, representing the optimization results in an embodiment of the present invention. Figure 38B is a graph showing the time course of the rotation angular velocity, boom angular velocity, and rope length velocity. Figure 38C is a graph showing the time course of the rotation angular acceleration, boom angular acceleration, and rope length acceleration. Figure 38D is a graph showing the time course of the suspended load swing angle.

[0156] Figure 39A is a graph showing the time course of the slewing angle, boom luffing angle, and rope length of the skilled operator's trajectory, representing the optimization results in an embodiment of the present invention. Figure 39B is a graph showing the time course of the slewing angular velocity, boom angular velocity, and rope length velocity. Figure 39C is a graph showing the time course of the slewing angular acceleration, boom angular acceleration, and rope length acceleration. Figure 39D is a graph showing the time course of the suspended load swing angle.

[0157] Furthermore, as mentioned above, Table 11 and Figure 40 show the operating time and load swing amount (angle) under other conditions, with the results for the two-stage S-shaped trajectory as the baseline. [Table 11]

[0158] Referring to Figures 36D and 37D, it can be seen that the maximum amplitude is suppressed in the three-stage S-shaped trajectory compared to the two-stage S-shaped trajectory. Furthermore, as shown in Figure 38D, the STT trajectory significantly reduces the load swing of the suspended load, resulting in highly effective results. However, achieving an STT trajectory requires rapid boom luffing to maintain a straight trajectory of the suspended load. In boom-luffing slewing cranes, the luffing speed is considerably smaller than the slewing speed. For this reason, achieving an STT trajectory can be difficult in some cases. Nevertheless, by appropriately combining luffing and slewing movements, it has been confirmed that load swing in both the tangential and radial directions can be effectively reduced, as shown in Figure 38D.

[0159] On the other hand, as shown in Figure 39C, the operating track used by a skilled operator exhibited characteristic acceleration and deceleration movements in the deceleration section, and an improvement in operating speed was expected compared to the two-stage S-shaped track. However, this speed improvement was limited to 0.5%, and no statistically significant difference was observed. Meanwhile, the maximum amplitude in the tangential direction of the suspended load increased by 8.4%, which may increase the load on the machine. From this perspective, the two-stage S-shaped track, the three-stage S-shaped track, and the STT track can be considered relatively more effective tracks.

[0160] As explained above, it was confirmed that combining slewing and luffing movements, such as in a three-stage S-shaped track or an STT track, is more effective in reducing tangential load swing than a two-stage S-shaped track. Therefore, in this embodiment, a combined track (boom luffing angular velocity track) that takes into account the maximum operating speed of the luffing movement in addition to the slewing movement is proposed. Furthermore, a track (rope vertical velocity track) that simultaneously performs the vertical movement of the main hoisting rope 50, which affects the vibration period of the suspended load LM, in addition to the luffing movement was also investigated.

[0161] Figure 41 is a graph showing the boom luffing angular velocity trajectory and rope vertical velocity trajectory, which are proposed in conjunction with the three-stage S-shaped trajectory of the slewing motion. The equations representing these trajectories are shown in Equations 29 and 30.

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[0162] Note that the time for each section of the boom elevation angular velocity track is t l The time for each section of the rope vertical velocity track is t h This is shown. The boom luffing angular velocity trajectory performs an raising operation in the first half of the rotation region relative to the target point, and a lowering operation in the second half of the rotation region. Figure 42 is a plan view showing the boom tip trajectory of the proposed trajectory that combines rotation and luffing operations. Figure 42 also shows a simple rotation trajectory and the aforementioned STT trajectory. Furthermore, the boom luffing angular velocity trajectory performs a hoisting operation in the first half of the rotation region relative to the target point, and a lowering operation in the second half of the rotation region. In addition, a cycloid curve is adopted as an S-shaped trajectory in the boom luffing angular velocity trajectory and in the acceleration and deceleration regions of the boom luffing angular velocity trajectory, similar to rotation. The S-shaped trajectory is not limited to this.

[0163] The trajectory patterns compared in this embodiment are shown below. Case S1: Compound track including a three-stage S-shaped trajectory (slewing + boom luffing). Case S2: Compound trajectory (swivel + rope movement) including a three-stage S-shaped trajectory. Case S3: Compound track including a three-stage S-shaped trajectory (slewing + boom luffing + rope raising / lowering). Case S4: Compound track including a two-stage S-shaped trajectory (slewing + boom luffing + rope raising / lowering).

[0164] The objective function is defined in Equation 22, based on minimizing the maximum amplitude of the suspended load in order to reduce the amount of damage to the crane 10. The operating time T is set in the same way as in the results for the two-stage S-shaped trajectory described above. Furthermore, the effect of reducing the maximum amplitude of the suspended load is also confirmed for the two-stage S-shaped trajectory when considering combined operation. In addition, the constraints to be added to the constraints in Equations 24 to 28 are shown in Equations 31 to 34. In this case, the total boom luffing time is T. l The total time spent ascending and descending the rope is T h This is how it is defined.

[0165] Equations 31 and 32 are the constraints in the time segments of equations 29 and 30 mentioned above.

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[0166] Tables 12 and 13 show examples of the limit values ​​included in each of the above formulas. In this case, the constraints regarding boom luffing speed and rope raising / lowering speed are set based on the performance of the actual crane. [Table 12] [Table 13]

[0167] Furthermore, the constraints for each operating condition are shown in Table 14. [Table 14]

[0168] For each proposed trajectory described above, optimization calculations were performed to minimize the maximum load swing amplitude considering the constraints, and laboratory-scale slewing crane experiments were conducted based on the results to confirm the effectiveness of the proposed trajectories in reducing the maximum load swing. A known sequential quadratic programming (SQP) method was used for the optimization calculations. The laboratory-scale crane 10 used is the same as that described in Figures 5 and 6 above.

[0169] As mentioned above, the behavior of the boom 16 and the suspended load LM is measured by a known motion capture system. In this embodiment as well, the time history profiles of the slewing of the slewing body 12, the luffing of the boom 16, and the rope up and down speed of the main hoisting rope 50, which were created in advance, are converted into speed command signals and transmitted to the DSP (Digital Signal Processing). Subsequently, the speed command signals are transmitted in real time from the DSP to each servo controller, thereby controlling the operation of the lab-scale slewing crane.

[0170] Figures 43A to 46D show the results of optimization calculations and lab-scale experiments for each of the proposed trajectories described above. Figure 43A is a graph showing the time evolution of the slewing angle, boom angle, and rope length in this embodiment. Figure 43B is a graph showing the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity in this embodiment. Figure 43C is a graph showing the time evolution of the slewing angular acceleration, boom angular acceleration, and rope length acceleration in this embodiment. Figure 43D is a graph showing the time evolution of the suspended load swing angle in this embodiment. The graphs in groups 44, 45, and 46 are similar. Group 43 corresponds to Case S1, group 44 to Case S2, group 45 to Case S3, and group 46 to Case S4.

[0171] Furthermore, Table 15 shows the maximum radial and tangential load swing angles and total operating time for a simple two-stage S-shaped trajectory (without boom luffing or rope movement) and for each proposed trajectory Case S1, S2, S3, and S4. [Table 15]

[0172] As shown in Table 15, it was confirmed that combining the slewing motion with the luffing motion of the boom or the up-and-down motion of the rope reduces the maximum amplitude in the tangential direction of the suspended load. In particular, in case S3, where the slewing motion, boom luffing motion, and rope up-and-down motion are performed simultaneously, the amplitude is reduced most effectively. In this case, an effect of reducing the amplitude by more than 30% was obtained compared to a simple two-stage S-shaped trajectory.

[0173] From the above, we were able to confirm the following effects. <Effects of boom luffing> By adding boom luffing during the slewing motion, the working radius of the crane 10 can be reduced. As a result, the centrifugal and inertial forces acting on the suspended load LM are reduced, and the amplitude of the suspended load LM is suppressed. Furthermore, boom luffing has the function of directly controlling the radial vibration of the suspended load LM. By performing boom luffing in conjunction with the slewing acceleration and deceleration of the crane 10, radial vibration of the suspended load can be directly controlled. This is thought to have shortened the overall operation time. This result indicates that the overall efficiency of crane operations can be improved.

[0174] <Effects of Rope Up / Down Movement> It was found that the vertical movement of the rope is a factor that directly affects the vibration period of the suspended load LM. It was shown that by winding the rope during the slewing motion and shortening the rope length relative to the initial rope length, the inertial force acting on the suspended load LM can be effectively reduced, thereby suppressing the maximum swing amplitude of the suspended load LM. From this, it was confirmed that dynamic control of the rope length is effective in suppressing vibration of the suspended load LM.

[0175] <Simulation and FEM analysis results> From the above results, it was confirmed that the trajectory that combines the three axes of rotation, luffing, and rope movement (3-axis combined motion trajectory) is the most efficient motion trajectory, enabling transport in a short time while suppressing load swing. Next, the stress generated in the lower boom 16A was compared using FEM simulation for the motion trajectory of a skilled operator and the 3-axis combined motion trajectory. First, in order to define the rotational angular velocity trajectory, an optimization calculation was performed under the conditions of the actual crane, similar to a lab-scale rotational crane. Table 16 shows the basic specifications of the actual crane, Table 17 shows the details of the upper and lower limit constraints in the simulation, and Table 18 shows the inequality constraints.

[0176] [Table 16] [Table 17] [Table 18]

[0177] For the maximum speed and maximum acceleration of slewing, boom luffing, and rope raising / lowering movements, constraints were set based on the specifications of the actual machine. Furthermore, for the combined motion trajectory, time constraints were set to ensure that the motion time was the same as that of a skilled operator, and optimization was performed to minimize the maximum load swing amplitude.

[0178] Figures 47A to 49D show the simulation results for each condition. Figure 47A is a graph showing the time changes of the slewing angle, boom angle, and rope length in the skilled operator's trajectory in this embodiment. Figure 47B is a graph showing the time changes of the slewing angular velocity, boom angular velocity, and rope length velocity in the same trajectory. Figure 47C is a graph showing the time changes of the slewing angular acceleration, boom angular acceleration, and rope length acceleration in the same trajectory. Figure 47D is a graph showing the time changes of the suspended load swing angle in the same trajectory.

[0179] Figure 48A is a graph showing the time evolution of the slewing angle, boom angle, and rope length in a compound operating trajectory including a three-stage S-shaped trajectory in this embodiment. Figure 48B is a graph showing the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity. Figure 48C is a graph showing the time evolution of the slewing angular acceleration, boom angular acceleration, and rope length acceleration. Figure 48D is a graph showing the time evolution of the suspended load swing angle.

[0180] Figure 49A is a graph showing the time evolution of the slewing angle, boom angle, and rope length in a compound operating trajectory including a two-stage S-shaped trajectory in this embodiment. Figure 49B is a graph showing the time evolution of the slewing angular velocity, boom angular velocity, and rope length velocity. Figure 49C is a graph showing the time evolution of the slewing angular acceleration, boom angular acceleration, and rope length acceleration. Figure 49D is a graph showing the time evolution of the suspended load swing angle.

[0181] The simulation results showed that the maximum load swing amplitude was reduced by 24.3% for the composite operating trajectory including a two-stage S-curve and by 28.8% for the composite operating trajectory including a three-stage S-curve compared to the skilled operator trajectory. This result confirmed that the proposed trajectory is effective in actual crane specifications as well as in lab-scale cranes. Next, FEM simulations were performed based on the velocity trajectories obtained through optimization, as shown in Figures 47B, 48B, and 49B, to evaluate the stress amplitude generated in the lower boom 16A. Figures 50A, 50B, and 50C show the load swing and stress amplitude results for the skilled operator trajectory, the composite operating trajectory including a three-stage S-curve, and the composite operating trajectory including a two-stage S-curve. Figure 51 is a graph comparing each result. The FEM simulation results showed that the stress amplitude generated in the lower boom 16A was reduced by 17.1% for the composite operating trajectory including a two-stage S-curve and by 17.7% for the composite operating trajectory including a three-stage S-curve compared to the skilled operator model trajectory. These results demonstrate the effectiveness of the proposed track design in reducing damage to working machinery.

[0182] Next, the effect of the difference in the amplitude of the generated stress obtained above on the lifespan of crane 10 was calculated based on the simplified fatigue evaluation method of ISO 4301-1, the international standard for cranes. Equation 35 is the formula for calculating the stress spectral coefficient Kp in the said fatigue evaluation method.

[0183]

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[0184] The design life is determined based on the coefficient Kp in Equation 35, where P i The magnitude of the load LM suspended by crane 10 during use, P max The maximum load LM that crane 10 is expected to handle is C i C is the average number of load cycles at each load level. T This is the sum of the individual load cycles for all load levels, m s This represents the slope constant. Slope coefficient m sThis is determined by the joining method being evaluated. If the crane 10 has a lattice structure, a lattice-type joint is applied, so m s The value =5 is applied. Also, P i / P max This shows the ratio of the stress amplitude under evaluation to the maximum stress amplitude. Here, based on the previous FEM simulation results, in the case of a skilled operator's trajectory, P i / P max =1.0, in the case of the trajectory proposed in this embodiment (3-stage S-shaped trajectory), P i / P max Let = 0.823. C i / C T This represents the frequency of occurrence of the stress amplitude being evaluated.

[0185] Figures 52A and 52B show the load profiles for the work assumed in the fatigue evaluation described above. Figure 52A represents the trajectory of a skilled operator, and Figure 52B corresponds to the trajectory proposed in this embodiment (a three-stage S-shaped trajectory). In this assumed work, work with load (load ratio: 100%) and work without load (load ratio: 55%) are performed at 50% frequency each. Furthermore, based on the FEM analysis results mentioned earlier, the proposed trajectory assumes a 17.7% reduction in load compared to the skilled operator trajectory.

[0186] Based on the above assumptions, the stress spectral coefficient Kp was calculated to be 0.527 for the skilled operator track and 0.208 for the proposed track. Furthermore, when the stress hierarchical grade was set to S0 and the ratio of the maximum number of operating cycles was calculated, the proposed track showed a maximum number of cycles (design life) approximately 2.7 times greater than that of the skilled operator track. From the above evaluation results, it was confirmed that the proposed method contributes significantly to improving the design life of the crane 10 compared to conventional operation.

[0187] As described above, in this embodiment, based on the analysis results of skilled operator operation on a real crane 10, it was confirmed that the tangential load swing of the boom 16 affects the stress generated in the lower boom 16A. Furthermore, the effectiveness of the proposed trajectory, which consists of a compound trajectory combining slewing, boom luffing, and rope up / down movements, was verified through optimization analysis and experiments on a lab-scale crane. As a result, it was confirmed that the trajectory of a so-called three-axis compound motion, which simultaneously performs slewing, boom luffing, and rope up / down movements, is the most effective trajectory for suppressing the maximum load swing amplitude of the suspended load in the same operating time as that of a skilled operator or a two-stage S-shaped trajectory. The effectiveness of this proposed trajectory was also reproduced in FEM simulations on a real crane and was consistent with the lab-scale verification results. In addition, it was confirmed that the maximum stress amplitude of the lower boom 16A generated in the proposed trajectory was reduced by up to 17.7% compared to the skilled operator trajectory. This stress reduction effect significantly suppresses the stress generated in the boom 16 compared to the conventional skilled operator track. Life calculations based on standards for fatigue evaluation of the crane 10 revealed that it is possible to achieve a life extension of approximately 2.7 times compared to the skilled operator track. These results confirm that the proposed track not only enables efficient operation but also significantly reduces the amount of damage to the crane 10, demonstrating its high practicality.

[0188] The crane 10 and its embodiments according to each embodiment of the present invention have been described above. With such a configuration, it is possible to efficiently move the suspended load LM to the target position while suppressing the swing of the suspended load LM at the target position. However, the present invention is not limited to these forms. The present invention can take the following modified embodiments, for example.

[0189] (1) The structure of the crane 10 is not limited to that shown in Figure 1, and may be a crane with other structures. The crane 10 may have a jib connected to the tip of the boom 16, and the crane 10 may be a tower crane or the like. Also, the crane 10 may have a gantry instead of a mast 20.

[0190] (2) The equations of motion of the suspended load LM used in the calculations performed by the target velocity calculation unit 702 are not limited to those used in the previous embodiment. Other equations of motion of the suspended load LM for the slewing direction and radial direction, respectively, including the length of the boom 16, the length of the main hoisting rope 50, and the elevation angle of the boom 16, may be used. In this case, the complete dynamics model based on the known Newton's equations of motion or Lagrange's equations of motion, or equations of motion obtained by eliminating any small terms from the complete dynamics model, may be used.

[0191] (3) In the above embodiments, conditions relating to the radial swing angle θ1 and the rotational swing angle θ2 were described in a manner in which conditions relating to the radial swing angle θ1 and rotational swing angle θ2 are set both at the target position and during rotational movement, but the present invention is not limited thereto. The swing angle conditions may be set only at the target position or only during rotational movement. In addition, some of the constraint conditions shown above may be applied.

[0192] (4) The profile of the slewing angular velocity may not be input to the slewing drive unit 71, but may be displayed on the display unit 87 so that the operator can operate according to the profile.

[0193] (5) In the second embodiment and the second example described above, the luffing of the boom 16 and the raising and lowering of the main hoisting rope 50 were mainly described in relation to the slewing motion, but it is also possible to describe a configuration in which only one of these is combined. Furthermore, when the luffing of the boom 16 is combined, the aforementioned STT track may be adopted.

[0194] (6) The S-shaped trajectory in the above embodiment constitutes the curved trajectory of the present invention. In a turning operation, the speed trajectory includes an acceleration zone from zero to maximum speed and a deceleration zone from maximum speed to zero again. Each of the acceleration zone and the deceleration zone is composed of multiple stages of curved trajectory. In the case of a two-stage S-shaped trajectory, one intermediate speed is provided between the start of the turn and the maximum speed, or between the maximum speed and the stop of the turn. In the case of a three-stage S-shaped trajectory, two intermediate speeds are provided between the start of the turn and the maximum speed, or between the maximum speed and the stop of the turn.

[0195] The speed trajectory from the start of a turn to the intermediate speed is composed of a single S-shaped trajectory. In this case, the S-shaped trajectory rises as a curve with the time axis (X-axis) as its tangent, and while having a downward-convex curved shape, it reaches an inflection point at half the intermediate speed. From this inflection point, it rises with a tangent parallel to the speed axis (Y-axis), and while having an upward-convex curved shape, it eventually reaches the intermediate speed. At this point, the tangent of the S-shaped trajectory becomes parallel to the time axis. The same applies to the S-shaped trajectory between the intermediate speed and the maximum speed. Note that the intermediate speed region does not necessarily require a predetermined time; the next S-shaped trajectory may start immediately after the first S-shaped trajectory reaches the intermediate speed (the intermediate speed time is effectively zero). In this case, the intermediate speed constitutes the inflection point between two consecutive S-shaped trajectories.

[0196] On the other hand, the speed trajectory from the maximum speed to the intermediate speed in the deceleration zone is composed of a single S-shaped trajectory. In this case, the S-shaped trajectory descends in a curve with the time axis as its tangent, and while having an upwardly convex curved shape, it reaches an inflection point at a speed midway between the maximum speed and the intermediate speed. From this inflection point, it descends with a tangent parallel to the speed axis, and while having an downwardly convex curved shape, it eventually reaches the intermediate speed. At this point, the tangent of the S-shaped trajectory becomes parallel to the time axis. The same applies to the S-shaped trajectory between the intermediate speed and zero speed (turning stop). In this case as well, the intermediate speed zone does not necessarily require a predetermined time, and the next S-shaped trajectory may start immediately at the intermediate speed.

[0197] The same applies to tracks with three or more stages. In this case, the number of intermediate speeds increases, and an S-shaped track (curved track) is provided between them.

[0198] In the above explanation, an S-shaped trajectory was used as an example of a curved trajectory, but it is not necessarily limited to this. Furthermore, the S-shaped trajectory is not limited to one composed of a cycloid curve, but may be composed of other curves. The cycloid curve mentioned above is an example of a trigonometric function curve in this invention. A cycloid curve is expressed as a combination of trigonometric functions. The S-shaped trajectory (curved trajectory) is not limited to these curves, but may consist of other curves such as a cycloid curve or an Nth-degree polynomial. [Explanation of Symbols]

[0199] 10 Cranes 12. Rotating body (upper main body) 13 Counterweight 14. Running body (lower body) 15 Cab 16. Boom (relief structure) 20 Mast 24 Boom guy lines 30 Boom luffing winch 34 Main winch 38. Boom luffing rope 50 Main hoisting rope (lifting rope) 57 Main hook 70 Control Unit 701 Drive Control Unit 702 Target velocity calculation unit (turning angle velocity setting unit, velocity setting unit) 703 Command signal generation section 704 Storage section 71 Swivel drive unit 72 Boom drive unit 73 Winch drive unit 74 Swivel control unit 75 Boom Operating Section 76 Winch operating section 81 Input Unit (Movement Information Reception Unit) 82 Swivel Angle Detection Unit 83. Elevation Angle Detection Unit 84. Rope length detection unit (rope length information acquisition unit) 85 Boom length acquisition unit (relief body length information acquisition unit) 86. Suspended load detection unit 87 Display section LM hanging load θ1 Radial runout angle θ2 Swing direction deviation angle θ3 relief angle θ4 rotation angle

Claims

1. Lower body and An upper body is supported on the lower body so as to be able to rotate around a pivot axis that extends vertically, A ripple body including a base end of a ripple body and a tip end of a ripple body opposite to the base end of the ripple body, which are supported on the upper body so as to be able to rotate in the ripple direction around a horizontal rotation center axis, A suspension rope is suspended from the tip of the aforementioned undulating body and connected to the suspended load, A pivot drive unit that receives a predetermined angular velocity command signal and can pivot the upper body around the pivot center axis at an angular velocity corresponding to the angular velocity command signal, A relief body length information acquisition unit acquires relief body length information, which is information corresponding to the length of the relief body in the longitudinal direction of the relief body, which is the direction connecting the base end and the tip end of the relief body. A swivel angle detection unit for detecting the swivel angle of the upper body around the pivot center axis, A relief angle detection unit for detecting the relief angle of the relief body around the rotation center axis, A rope length information acquisition unit acquires rope length information, which is information corresponding to the length of the suspension rope between the tip of the raised body and the suspended load. A movement information receiving unit receives movement information, including a target rotation angle, for moving the suspended load to a predetermined target position around the rotation center axis by the rotational movement of the upper body, starting from an initial state in which the suspended load is lifted by the suspension rope. A speed setting unit sets the angular velocity of the upper body up to the target position to include multiple curved trajectories in each of the acceleration and deceleration zones, such that the radial swing angle is defined as the angle of the suspension rope with respect to the vertical direction when the raised body is viewed along the rotational direction of the upper body, and the rotational swing angle is defined as the angle of the suspension rope with respect to the vertical direction when the raised body is viewed along the radial direction of the rotational movement of the upper body. Based on the equations of motion of the suspended load for each of the rotational and radial directions, which include at least the length of the raised body, the length of the suspension rope, and the raised angle, the speed setting unit sets the angular velocity of the upper body up to the target position to include multiple curved trajectories in each of the acceleration and deceleration zones, such that the radial swing angle and the rotational swing angle at the target position are smaller than a predetermined threshold angle and the time it takes for the suspended load to reach the target position is minimized. A command signal generation unit generates and outputs an angular velocity command signal corresponding to the angular velocity set by the speed setting unit, A work machine equipped with the following features.

2. The work machine according to claim 1, wherein the curved trajectory is composed of a trigonometric function curve.

3. The work machine according to claim 1 or 2, wherein the command signal generation unit inputs the generated angular velocity command signal to the slewing drive unit.

4. The work machine according to claim 1 or 2, wherein the speed setting unit further sets the rotational angular velocity of the upper body such that the rotational angular velocity of the upper body becomes smaller than a preset maximum rotational angular velocity during the rotational operation.

5. The work machine according to claim 1 or 2, wherein the speed setting unit further sets the angular velocity of the upper body such that the rotational angular acceleration of the upper body is less than a preset maximum rotational angular acceleration during the rotational operation.

6. The working machine according to claim 1 or 2, wherein the speed setting unit sets the angular velocity based on the following equations I and II as the equations of motion for the suspended load. ml ２ (1 + θ １ ２ )θ １ ’’ + ml ２ θ １ θ ２ θ ２ ’’ + mlL(cosθ ３ - θ １ sinθ ３ )θ ３ ’’ - ml ２ θ ２ θ ４ ’’ + ml ２ θ １ (θ １ ’ ２ + θ ２ ’ ２ ) - mLl(sinθ ３ + θ １ cosθ ３ )θ ３ ’ ２ - ml(lθ １ + Lsinθ ３ )θ ４ ’ ２ - 2ml ２ θ ２ ’θ ４ ’ + mglθ １ + 2mlθ １ ’l’(1 + θ １ ２ ) - mθ １ l’ ２ - mLθ １ θ ３ ’l’sinθ ３ + 2mlθ １ θ ２ θ ２ ’l’ = 0 ··· (Equation I) ml ２ θ １ θ ２ θ １ ’’ + ml ２ (1 + θ ２ ２ )θ ２ ’’ + mlLθ ２ sinθ ３ θ ３ ’’ + ml(Lsinθ ３ + lθ １ )θ ４ ’’ + ml ２ θ ２ (θ １ ’ ２ + θ ２ ’ ２ ) - mLlθ ２ cosθ ３ θ ３ ’ ２ - ml ２ θ ２ θ ４ ’ ２ + 2mLlθ ３ ’θ ４ ’cosθ ３ + 2ml ２ θ １ ’θ ４ ’ + mglθ ２ + 2mlθ １ θ ４ ’l’ - mLθ ２ θ ３ ’l’sinθ ３ + 2mlθ ２ ’l’(1 + θ ２ ２ ) - mθ ２ l’ ２ + 2mlθ １ θ ２ θ １ ’l’ = 0 ··· (Equation II) (However, θ １ : Radial swing angle of the suspended load, θ ２ : Swinging angle in the turning direction of the suspended load, θ １ ’: Radial swing angular velocity of the suspended load, θ ２ ’: Swinging angular velocity in the turning direction of the suspended load, θ １ ’’: Radial swing angular acceleration of the suspended load, θ ２ ’’: Swinging angular acceleration in the turning direction of the suspended load, θ ３ : Heaving angle of the heaving body with respect to the vertical direction, θ ３ ’: Change rate of the heaving angle, θ ３ ’’: Change acceleration of the heaving angle, θ ４ : Turning angle of the upper body, θ ４ ’: Turning angular velocity of the upper body, θ ４ ’’: Turning angular acceleration of the upper body, g: Gravitational acceleration, L: Length of the heaving body, l: Length of the suspended load rope from the tip of the heaving body to the suspended load, l’: Change rate of the length of the suspended load rope, m: Mass of the suspended load)

7. The work machine according to claim 1 or 2, wherein the speed setting unit sets the angular velocity of the upper body to reach the target position to include a two-stage curved trajectory in both the acceleration and deceleration regions.

8. The work machine according to claim 1 or 2, wherein the speed setting unit sets the angular velocity of the upper body to reach the target position to include three stages of curved trajectories in both the acceleration and deceleration zones.

9. The work machine according to claim 1 or 2, wherein the speed setting unit sets the speed of rotation of the undulating body such that in the acceleration region of the angular velocity of the upper body, the undulating body rotates in the upright direction, and in the deceleration region, the undulating body rotates in the downward direction.

10. The work machine according to claim 1 or 2, wherein the speed setting unit sets the speed for raising and lowering the load rope such that the load is raised in the acceleration region of the angular velocity of the upper body and the load is lowered in the deceleration region.

11. The work machine according to claim 1 or 2, wherein the speed setting unit sets the speed of rotation of the luffing body such that in the acceleration region of the angular velocity of the upper body the luffing body rotates in the upright direction and in the deceleration region the luffing body rotates in the downward direction, and sets the speed of winding up and winding down the load rope such that in the acceleration region of the angular velocity of the upper body the suspended load is raised and in the deceleration region the suspended load is lowered.

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