JP3237557B2 - Sway control method for crane hanging load - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a steady rest of a crane suspended load in a rope suspended crane.

[0002]

2. Description of the Related Art In general, in crane operation, it is desired to shorten a so-called cycle time from lifting a load, traveling laterally to unloading the load, and to increase the cargo handling efficiency as much as possible. At this time, if a residual deflection of the load occurs at the end of the lateral traveling, the suspended load cannot be unloaded for safety reasons. Therefore, it is necessary to wait until the load deflection falls within an allowable range.
This results in increased cycle times and reduced handling efficiency. In particular, in manned cranes, steady rest control based on the driver's intuition and experience is performed, and it takes a considerable amount of time to become skilled.

On the other hand, there are two types of steady rest control mechanisms in an unmanned crane, a mechanical control mechanism and an electric control mechanism. In the former mechanical control mechanism, since a movable portion such as a crane hook is structurally fixed, no shake is generated in principle, and complete swing prevention control is possible. However, for example, on the premise that existing equipment is modified, the latter electrical control mechanism is often more advantageous in terms of cost. In addition, the mechanical control mechanism needs to hoist the suspended load to the highest position before traveling, which is disadvantageous in cycle time. From such a point, the necessity of a crane provided with an electric steady rest mechanism has been increased.

Conventionally, in a crane operation control method having an electric steady rest control mechanism, an acceleration / deceleration time related to a swing cycle of a suspended load is set based on a model in which a crane-suspended load system is regarded as a single pendulum, and a physical In many cases, speed pattern control that does not leave a run-out in the law is adopted. The currently known speed pattern control methods can be roughly classified as shown in FIG.
As shown in FIG. 10, a method in which a plurality of time sections in which the crane acceleration during operation is constant is controlled so that the crane speed pattern is a polygonal line as shown in FIG. 10B (Japanese Patent Publication No. 61-031032). And FIG.
A method in which the crane acceleration is continuously changed as shown in FIG. 11A and the crane speed pattern is controlled so as to draw a smooth continuous curve as shown in FIG.
05686). In the latter publication, it is stated that by making the acceleration change continuous, it is difficult to induce backlash of the reduction gear and torsion of the drive shaft, and it is possible to realize high-precision anti-sway.

[0005] Although all of the above-described crane-hanging load systems are regarded as simple pendulums, there are cases where a crane that is more severe in terms of cycle time simultaneously lifts and lowers a rope that suspends a hanging load and travels at the same time. is there. In such a case, if an attempt is made to generate a steady rest pattern while taking into account the swing cycle corresponding to the continuously changing rope length, the complexity becomes much more complicated than when the rope length is fixed. This is because the solution of the equation of motion of the suspended load taking into account the change in the rope length cannot be expressed by elementary functions. Then, an operation control method based on this equation of motion was strictly devised, but the number of operations was extremely large, which severely restricted the control device and was not practical.

Therefore, a simple operation control method based on a simple pendulum model in the case where the rope length is fixed is disclosed in Japanese Patent Application Laid-Open No. Hei 5-270786 as being applicable to simultaneous operation of hoisting / lowering and running. There is an anti-sway control method for the suspended load. The suspension control method of the suspended load of the same publication determines the swing period of the suspended load by considering the average value of the rope length related to the lifting and lowering of the suspended load rope as a representative value of the rope length that changes with time. The vibration is stopped by the speed pattern control.

[0007]

However, the steady rest control method disclosed in the above-mentioned publication is intended for an overhead crane having a small hoisting / lowering speed range (8 m / min) and is capable of detecting a discontinuous acceleration change. It is based on the speed pattern you have. Therefore, it cannot be applied to a container crane having a large hoisting / lowering speed range, for example, a container crane that unloads and unloads containers on a quay. Therefore, the speed of hoisting / unwinding is 70 m / min to 150 m / m.
As a method for performing the steadying control in a container crane having “in”, for example, it is conceivable to control the speed of the crane based on an acceleration pattern in which the acceleration changes discontinuously as shown in FIG. The acceleration pattern shown in FIG. 12 is a steady vibration acceleration pattern when the vehicle travels while hoisting a load, and switches the acceleration from η ₃ to η ₄ after a lapse of half the total acceleration time.

As described above, even if the acceleration pattern changes the acceleration discontinuously, it is theoretically possible to realize the steady rest. However, in reality, if the acceleration is changed discontinuously, adverse effects such as slipping of the crane and rattling of the reducer will occur, and not only will it not be possible to achieve accurate steady rest, but it will also lead to machine failure there is a possibility.

Further, many container cranes are not self-propelled, but, for example, of a type in which a trolley 57 is pulled by a wire rope 55 stretched from a motor 53 installed in an electric room 50 as shown in FIG. Moreover, in this method, the total length of the wire rope 55 reaches 200 m, which is equivalent to the existence of a spring between the motor 53 and the trolley 57. For such a container crane,
According to the acceleration pattern shown in FIG.
7, the vibration of the trolley 57 is suddenly changed and the wire rope 55 pulling the trolley is affected by the abrupt change in the acceleration (effect of the spring). You can't get it.

The present invention has been made in view of the above circumstances, and it is possible to achieve high-precision anti-vibration even for a crane having a high hoisting / lowering speed and a driving system having a spring characteristic or the like. It is an object of the present invention to provide a method for controlling a steady rest of a crane hanging load.

[0011]

Deflection of the crane suspended load according to the present invention SUMMARY OF] stop control method, One performs winding suspended load
The suspension control of the suspended load is performed by performing the traveling control of the suspended crane that travels on the basis of a predetermined speed pattern.In the acceleration section, the speed pattern is accelerated to a predetermined speed in the acceleration section, consist of accelerated constant speed section for holding said predetermined speed, the suspended load
Putter in the acceleration section where the vehicle runs while rolling up
The emissions, straight from zero value over time T ₁ until a predetermined acceleration eta ₁
A linear increasing step A and the acceleration η ₁ during a time T _2.
B, and the acceleration η ₁ over time T ₃ .
A step C of linearly changing the acceleration to a predetermined acceleration η ₂ from
A step D of maintaining the acceleration η ₂ for a time T ₄ ;
₅ to decrease linearly from the acceleration η ₂ to zero
And the above-mentioned T ₁ , T ₂ , T ₃ , T ₄ ,
The relationship between T ₅ , η ₁ , η _{2 at} the end of step E is
The swing angle of the suspended load and the swing angular velocity of the suspended load are set to zero values. Also, lower the suspended load
In the crane hanging load steadying control method for performing the swing control of the suspended load by performing the running control of the suspended crane that travels while performing based on a predetermined speed pattern, a deceleration section in which the speed pattern is reduced from a predetermined speed. In the deceleration section where the vehicle travels while lowering the suspended load.
The definitive acceleration patterns, away from the zero value over a period of time T ₁
Step A for linearly decreasing to a constant acceleration −η ₁
A step B of holding the acceleration eta ₁ between between T _2, time T
₃ from the acceleration eta ₁ over to a predetermined acceleration eta ₂
A linearly varying step C and said acceleration for a time T ₄
A step D for holding at −η ₂ and the acceleration over time T ₅
Structure and a step E for linearly increases from eta ₂ to zero value
Form, wherein _{T 1, T 2, T 3} , T 4, T 5, -η 1, at the end of the relationship eta ₂ are step E, the suspended load deflection angle and the suspended load of the shake angular velocity is zero value It is set to become.

Further, the time T ₂ and the time T ₄ are set to zero values, and there is no section for keeping the acceleration at a constant value.

Further, the time T ₁ is equal to the time T ₅ .

Further, the initial rope length at the start of acceleration or deceleration or the swing cycle and winding speed associated with the initial load and the suspended load are divided into appropriate sections.
In the dimension parameter table, the T ₃ and the acceleration η
₁ and η ₂ , or the T ₃ and the accelerations η ₁ and η
5. The steady rest control of a crane hanging load according to claim 4, wherein a ratio of ₂ is stored, and a steady rest parameter suitable for the operating condition is derived from the two-dimensional parameter table by interpolation calculation before the crane operation. Method.

Further, the steady rest pattern generating section and the steady rest parameter calculating section are registered as separate tasks in a computer equipped with a multitasking operating system, and the steady rest pattern generating section calculates the steady rest pattern of the work. In parallel with this, the steady rest parameter of the next work is calculated by the steady rest parameter calculating unit from the next work operating condition comprising the rope length or the swing cycle at the start of acceleration or deceleration and the winding speed. 4. The method for controlling the steady rest of a suspended load of a crane according to 4.

[0016]

FIG. 1 is a block diagram showing an automatic control device for a crane to which a crane operation control method according to an embodiment of the present invention is applied. In the figure, reference numeral 1 denotes a trolley, which travels in the x direction on a rail 2 while lifting and lowering a suspended load 3 attached to a lower end of a rope 4. The traveling of the trolley 1 is controlled by a trolley position detecting device 11 and a rope length detecting device 12.
A speed pattern generating device 13, a traveling motor control device 14, a traveling speed control motor 15, a hoisting / lowering speed control device 16, and a hoisting / lowering speed control motor 17.

The trolley position detecting device 11 is a device for detecting the position of the trolley 1 traveling on the rail 2 from the starting point, and detects the traveling position of the trolley 1 from the rotation amount of the wheels of the trolley 1 and the like. Is available. The rope length detecting device 12 is a device for detecting the length of the rope 4 during traveling, and detects the length of the rope 4 from the number of rotations of the hoisting / lowering motor 19 of the rope 4. I have. The speed pattern generator 13 is a device that generates a speed pattern to be applied to the trolley 1 according to an acceleration pattern given in advance. Traveling motor control device 15
Is constituted by a minor control loop for realizing an operation speed command given to the traveling speed control motor 15 from the outside.

By such an automatic control device, a crane operation control method according to the following embodiment of the present invention is realized. In this embodiment, as shown in FIG.
The mass of the suspended load 3 is m, the swing angle of the suspended load 3 is θ, and the trolley 1 is
Is the position of x, and the trolley 1 is accelerated on the rail 2 by d ² x
It is assumed that the vehicle travels at / dt ² (hereinafter referred to as α) and the length L of the rope length 4 changes with time. Assuming that the swing of the suspended load 3 is not large, a description will be given using a motion equation of the swing angle θ viewed from the trolley 1 expressed by the following equation (1).

[0019]

(Equation 1)

Here, it is assumed that the rope length L changes as L = a + bt (where a: initial rope length, b: hoisting / lowering speed). At this time, (1)
The solution of the equation is represented using the bessel function, and its analytical properties are complicated. In particular, the higher the hoisting / unwinding speed, the more difficult it is to analytically derive the steady rest speed pattern. Therefore, in the following, a steady rest acceleration pattern is derived by a computer using an optimization method so that both the suspended load swing angle θ and the swing angular velocity dθ / dt become zero at the end of acceleration (or deceleration) of the trolley 1. .

FIG. 3 shows the most general acceleration pattern of the present invention when the trolley 1 runs while hoisting a suspended load. The acceleration pattern shown in FIG. 3 shows a time change of the acceleration in the acceleration section, and the acceleration is changed from a zero value to a predetermined acceleration η over time T _1.
A step A for linearly increases to _1, the linear step B of holding the acceleration during the time T ₂ in the acceleration eta _1, the acceleration from the acceleration eta ₁ over time T ₃ to a predetermined acceleration eta ₂ C, a step D of maintaining the acceleration at the acceleration η ₂ for a time T ₄ , and a step E of linearly decreasing the acceleration from the acceleration η ₂ to a zero value over a time T _5. It consists of In this acceleration pattern, the specific values of the times T ₁ , T ₂ , T ₃ , T ₄ , T ₅ and the acceleration ratio η ₂ / η ₁ are derived by the computer using the optimization method as described above. I do.

Next, the initial rope length is 25 m and the winding speed is -1.
The effect of the present embodiment will be described by taking as an example a case where the vehicle travels while hoisting at a speed of 0.5 m / s ² with a trolley maximum acceleration of 0.5 m / s. For the sake of simplicity, the acceleration rise time T _{1 is} set so that the acceleration fall time T _{5 is} 3.0 seconds, and the acceleration hold time T _{2 is} equal to T ₄ = 0.0. The acceleration pattern under this condition is as shown in FIG.
The steady rest parameters are T ₃ and the acceleration ratio η ₂ / η ₁ .

Assuming that there is no spring characteristic between the motor and the trolley in the container crane shown in FIG. 13, if a computer calculates parameters using an optimization method so as to realize steadying at the end of acceleration, T ₃ = 5.816 sec η ₂ / η ₁ = 1.348 When the total acceleration time and the acceleration ratio η ₄ / η ₃ , which are parameters for the acceleration pattern shown in FIG. 12, are obtained as a comparative example, the total acceleration time is calculated as 9.089 η ₄ / η ₃ = 1.184. .

Next, consider a model having a spring characteristic between the motor and the trolley in the container crane shown in FIG. In this model, it is assumed that a damper is mounted to attenuate the vibration caused by the spring. First,
Assuming that the trolley position command value calculated from the motor speed instruction value is Xref and the actual trolley position is X, the trolley motion equation is as shown in the following equation (2).

[0025]

(Equation 2)

By applying the acceleration pattern of this embodiment shown in FIG. 4 and the acceleration pattern of FIG. 12 to the above equation of motion, a change in the speed of the trolley and a change in the swing angle of the suspended load were simulated. In the following simulation,
ζ / m was 0.15 / s, and K / m was 10.0 / s ² . FIGS. 5 and 6 show simulation results. FIG. 5 shows the result of the acceleration pattern of the present embodiment, and FIG. 6 shows the result of applying the acceleration pattern of FIG. FIGS. 5 (a) and 6 (a) show a change in the speed of the trolley. In the drawings, a dotted line indicates a speed command value given to the motor, and a solid line indicates the speed of the trolley. FIG.
(B) and FIG. 6 (b) show the change in the swing angle of the suspended load.

As can be seen from FIGS. 5 (a) and 6 (a), the trolley speed oscillates under the influence of the spring characteristics in both the embodiment and FIG. Is smaller when the acceleration pattern is applied. Therefore, as can be seen from FIGS. 5B and 6B, the steady rest error at the end of acceleration is ± 0.2 degrees in the conventional method, but ± 0.08 degrees in the present invention. And has been greatly reduced. From the above simulations, it was confirmed that according to the acceleration pattern of the present embodiment, the steady rest can be accurately realized even for a crane of a type in which a trolley is pulled by a wire rope as shown in FIG.

When applying the steady rest control method of the present invention to an actual crane, it should be noted that operating conditions (initial rope length and hoisting speed) are different for each crane operation, and the steady rest is different for each different operating condition. The difference is that the parameters are different. Therefore, the following two methods are presented as methods for obtaining the steady-state parameters for each operating condition.

In the first method, as a pre-processing device of the steady rest pattern generating device 13 shown in FIG. 1, a steady rest parameter for interpolating and calculating an appropriate steady rest parameter from a steady rest parameter table in accordance with an operating condition. A computing device is provided. FIG. 7 is an explanatory diagram for explaining the first method. The first method will be described with reference to FIG. A steady rest table that covers the assumed operating conditions is prepared, and steady rest parameters are calculated offline for each operating condition, and are substituted into the steady rest table. In the steady rest parameter table, the vertical axis represents the initial rope length, and the horizontal axis represents the winding speed. Theoretically, the rope length (measurement rope length) and the runout cycle have a one-to-one relationship. However, in practice, the length to the center of gravity changes depending on the weight of the suspended load, so the runout cycle differs even if the measurement rope length is the same. A case exists. Therefore, it is appropriate to use the rope length (rope length to the center of gravity) calculated backward from the actual swing period as the vertical axis. It is also conceivable that the swing cycle itself is used as the vertical axis instead of the rope length. The swing cycle at this time is derived by storing the measured swing cycle in a two-dimensional table including the measured rope length and the amount of suspended load, and interpolating the straight line.

In this example, the initial rope length is 5 m to 25 m.
2.5 to 5m increments, winding speed from -1.0m / s to 1.0m / s
Up to 0.5 m / s, and stores steady rest parameters (for example: T ₃ , η ₂ / η ₁ ) at each point. Then, the steady rest parameter to be used is calculated by linearly interpolating this table with respect to the actual operating condition. Generally, the steady rest parameter (T
₃ , η ₂ / η ₁ ) does not have a linear relationship between the initial rope length and the winding speed. As a method to minimize this error,
It is conceivable to make the table mesh finer,
There is a problem that the trouble of offline calculation increases. Therefore, this method can be adopted when the operating conditions are relatively limited and the vertical and horizontal ranges of the table are narrow, or when it is not necessary to provide a highly accurate steady rest. In the above example, T ₃ and the acceleration ratio η ₂ /
η ₁ is shown, but T ₃ and accelerations η ₁ , η
₂ or T ₃ and the acceleration ratio η ₁ / η ₂ may be substituted.

The second method is to derive high-precision steady-state parameters free from errors due to linear interpolation without using a steady-state parameter table. FIG. 8 is an explanatory diagram for explaining the second method. As shown in FIG. 8, a steady rest pattern generating unit and a steady rest parameter calculating unit are registered as separate tasks in a computer equipped with a multitasking operating system. And, while calculating the work in the steady rest speed pattern generation unit,
Based on the shake model (1) and the operating conditions of the next work, the steady rest parameters of the next work are calculated by optimization. Such a configuration has become feasible due to recent improvements in computer performance and advances in the operating system (OS). It is advisable to use this method when very high-accuracy steady rest is required, or when the operating conditions are liable to change and the meshing method of the parameter table is not uniquely determined. Also in this case, the length of the center of gravity rope is required, and the swing period table is linearly interpolated.
While the method of (1) linearly interpolates both the shake cycle table and the steady-state parameter table, errors accumulate, whereas this method is only affected by the linear interpolation error of the shake cycle table.

The acceleration pattern shown in FIG. 3 is an example in the case where the vehicle travels while hoisting a suspended load in the acceleration traveling section of the crane. In the case of the deceleration traveling section of the crane, the absolute values of η ₁ and η ₂ are the same. And reverse the sign. Also, when traveling while lowering the suspended load,
As shown in FIG. 9, in step C, the acceleration may be linearly decreased from the acceleration η ₁ to the predetermined acceleration η ₂ over time T ₃ . However, the acceleration pattern shown in FIG. 9 is not limited to the case where the vehicle travels while lowering the suspended load. If the effect of natural attenuation is greater than the effect of natural attenuation, the acceleration pattern may be as shown in FIG.

Further, by combining the speed pattern control based on the present invention and the feedback control using the deflection angle sensor signal, a control system resistant to disturbances and modeling errors can be constructed.

[0034]

As described above, in the present invention,
The acceleration pattern that controls the travel of the suspended crane that travels while lifting or lowering the suspended load is continuously changed, so the lifting and lowering speed is high and the drive system has spring characteristics etc. High-precision steady rest can also be achieved for cranes.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an automatic control device for a crane applied to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating operations of a crane and a suspended load applied to one embodiment of the present invention.

FIG. 3 is a graph showing an acceleration pattern according to an embodiment of the present invention.

FIG. 4 is a graph showing an acceleration pattern according to another embodiment of the present invention.

FIG. 5 is a diagram illustrating a simulation example in which the present embodiment is applied to a crane model having a spring characteristic between a motor and a trolley.

FIG. 6 is a diagram showing a simulation example in which an acceleration pattern in which acceleration changes discontinuously is applied to a crane model having spring characteristics between a motor and a trolley.

FIG. 7 is an explanatory diagram illustrating a first method of deriving a steady rest parameter.

FIG. 8 is an explanatory diagram illustrating a second method for deriving a steady rest parameter.

FIG. 9 is a graph showing an acceleration pattern according to another embodiment of the present invention.

FIG. 10 is a diagram showing an example of a known steady rest pattern.

FIG. 11 is a diagram showing another example of a known steady rest pattern.

FIG. 12 is a graph showing an acceleration pattern in which acceleration changes discontinuously.

FIG. 13 is a schematic diagram of a driving method of a container crane.

[Explanation of symbols]

 Reference Signs List 1 trolley 2 rail 3 suspended load 4 rope

Continuation of the front page (56) References JP-A-6-305686 (JP, A) JP-A-7-257876 (JP, A) JP-A-7-81875 (JP, A) JP-A-8-324496 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B66C 13/22

Claims (7)

(57) [Claims] 1. A method for controlling the suspension of a suspended load of a crane, wherein the traveling control of a suspended crane that travels while hoisting the suspended load is performed based on a predetermined speed pattern. The speed pattern is composed of an acceleration section in which the crane is accelerated to a predetermined speed, and a constant speed section in which the crane is accelerated in the acceleration section and which holds the predetermined speed.
The pattern is linearly changed from a zero value to a predetermined acceleration η ₁ over time T _1.
Hold at the acceleration η ₁ for the increasing step A and the time T ₂
And a predetermined time from the acceleration η ₁ over time T _3.
A step C for linearly changed until acceleration eta _2, time T ₄
A step D for holding the acceleration eta ₂ between, over time T ₅
Linearly decreasing the acceleration η ₂ from the acceleration η ₂ to zero.
E, and the relationship among T ₁ , T ₂ , T ₃ , T ₄ , T ₅ , η ₁ , η _{2 is} that at the end of the process E, the swing angle of the suspended load and the swing angular velocity of the suspended load are A method for controlling the steadying of a crane suspended load, wherein the method is set to be a zero value. 2. A method for controlling the suspension of a suspended load of a crane, wherein the traveling control of the suspended crane that travels while lowering the suspended load is performed based on a predetermined speed pattern. The speed pattern is composed of a deceleration section in which the speed pattern is decelerated from a predetermined speed, and acceleration in a deceleration section in which the vehicle travels while lowering the suspended load.
Pattern, over time T ₁ linearly from zero value to a predetermined acceleration eta ₁
A step A of reducing the, in the acceleration eta ₁ during the time T ₂
Step B of holding, and taking the time ₋₃ to determine whether the acceleration −η ₁
C to linearly change the acceleration to a predetermined acceleration −η ₂
When a step D for holding the acceleration eta ₂ during the time T _4,
From the acceleration eta ₂ over time T ₅ linearly to zero value
Constructed and a step E of increasing the _{T 1, T 2, T 3} , T 4, T 5, -η 1, relationship eta ₂ is at the end of the process E, suspended load deflection angle and the suspended load A swing angular velocity of the crane suspended load is set to zero value. Wherein the said time T ₂ and the time T ₄ the zero value, steadying control method according to claim 1 or 2, wherein the crane suspended load, characterized in that no section that holds the acceleration to a constant value . 4. A steadying control method according to claim 1 or 2, wherein the crane suspended load, characterized in that equal the T ₅ the time T ₁ and time. 5. A steadying control method for a crane suspended load according to claim 3, characterized in that equal T ₅ the time T ₁ and time. 6. The two-dimensional parameter table configured by dividing an initial rope length at the start of acceleration or deceleration or a swing cycle and a winding speed associated with the initial rope length and a suspended load into appropriate sections, the T ₃ and the T ₃ The accelerations η ₁ and η ₂ , or the T ₃ and the ratio of the accelerations η ₁ and η ₂ are stored, and before the operation of the crane, the steady rest parameter suitable for the operating condition is interpolated from the two-dimensional parameter table by interpolation. The steady rest control method for a crane suspended load according to claim 5, wherein the method is derived. 7. A method for registering a steady rest pattern generating unit and a steady rest parameter calculating unit as separate tasks in a computer equipped with a multitask operating system, and calculating the steady rest pattern of the work by the steady rest pattern generating unit. In parallel with this, the steady rest parameter of the next work is calculated by the steady rest parameter calculating unit from the next work operating condition comprising the rope length or the swing cycle at the start of acceleration or deceleration and the winding speed. 5. The method for controlling a steady rest of a suspended load of a crane according to 5 .