JP4883272B2 - Crane steady rest control method - Google Patents

Description

  The present invention relates to a steadying control method for a crane capable of traversing and winding.

  In carrying a suspended load using a crane such as an overhead crane or a container crane, a control technology is required for carrying it to the destination in the shortest time and yet keeping it steady.

  FIG. 5 shows a schematic diagram of a crane capable of traversing and winding operations. The crane 24 can wind the suspended load 21 via the winding rope 22, and can simultaneously run the traveling body 23. When the suspended load 21 is transported, the suspended load 21 swings due to inertia due to acceleration / deceleration of the traveling body 25, which hinders the cargo handling operation. Therefore, various swings are made so that the swing angle θ becomes zero. Stop control has been proposed.

As one of these steadying controls, a feedforward control design method called an input shaping method is known (for example, Non-Patent Document 1).
In the input shaping method, as shown in FIG. 6, the vibration 35 caused by the first impulse 31 is canceled by the vibration 34 caused by the second impulse 33 generated after the lapse of ΔT time.

  Further, a two-stage acceleration method is known as an application of the input shaping method to crane steady-state control, and has already been put into practical use (for example, Non-Patent Documents 2 and 3). In the two-stage acceleration method, the swing of the suspended load 21 caused by the first stage acceleration (deceleration) is canceled by the second stage acceleration (deceleration).

  As shown in FIG. 7, in the two-stage acceleration method, acceleration 42 is performed at a constant acceleration from the stop state 41, the speed is constant 43 when half the maximum speed, and the elapsed time from the start of acceleration is based on the length L of the winding rope 22 After maintaining the speed 43 until the pendulum half-cycle T1, acceleration 44 is performed at a constant acceleration, and a constant speed traversing operation 45 is performed at the maximum speed. As a result, the suspended load 21 moves at a constant speed together without moving relative to the traveling body 25.

  Similarly, when decelerating from the maximum speed, the vehicle is decelerated 46 with a constant deceleration, and when the speed is half of the maximum speed, the speed is constant 47. The elapsed time from the start of deceleration is the half period of the pendulum based on the length L of the winding rope 22 After the constant speed 47 is maintained until T2 is reached, the vehicle is decelerated 48 at a constant deceleration to stop (traversal end) 49.

  FIG. 8 is a flowchart of steadying control by the above-described two-stage acceleration method when the conventional crane 24 is automatically operated. Before starting operation, create a traverse / winding speed pattern (transverse / winding speed time series) based on maximum speed, maximum acceleration, destination, winding length during acceleration, winding length during deceleration, etc. The operation is performed based on the speed pattern.

  Furthermore, in this control method, residual shake may be large due to initial shake, traverse winding, dynamic characteristics, speed error, etc., and Patent Document 1 has been proposed to solve this.

Patent Document 1 performs operation with a predetermined speed pattern, operation with a speed pattern in which only the deceleration portion of the default speed pattern is corrected, and operation with a speed pattern in which only the acceleration portion of the default speed pattern is corrected, As shown in FIG. 9, the point on the phase plane at the time of traversing stop when driving with the predetermined speed pattern is P1, and only the deceleration portion of the predetermined speed pattern is increased by time ΔT with respect to P1 on the phase plane. Assuming that the change vector is Vd, and the change vector for P1 on the phase plane when only the acceleration portion of the predetermined speed pattern is increased by time ΔT is Va, these vectors Vd and Va are synthesized to synthesize V0 in the figure. The shake can be stopped by bringing the position of the traverse stop time on the phase plane to the origin. That is, if it can be expressed by V0 = αVd + βVa, the shake can be stopped by increasing the time of the deceleration portion by αΔT and the time of the acceleration portion by βΔT.
In other words, in the case of a crane that is transported to the same place many times, Patent Document 1 uses the first few times for adjustment, integrates the motion equation identified in advance while operating the crane, Adjustment is performed and steady rest is performed.

N. C. Singer and W.W. P. Seeing, “Preshaping Command Inputs to Reduce System Vibration”, ASME Journal of Dynamic Systems, Measurement, and Control, Vol. 112, pp. 76-82, 1990 Taku Sudo: “Automatic adjustment of crane steady rest”, IEEJ Technical Report, No. 943, p16-19 (2003) Shuntaro Suzuki, Shigeki Murayama, Satoshi Hayashi: “Container Control of Container Crane”, Proc. Kawasaki

JP 2003-341975 A, "Crane steadying method"

In the conventional two-stage acceleration method described above, residual runout may remain due to an error in the initial winding rope length due to a difference in the center of gravity position of the suspended load. In other words, in the conventional method, it is assumed that the center of gravity of the suspended load is always at a fixed position. If the position of the center of gravity is fluctuated, the identification accuracy is lowered, so that the shake after steadying becomes large.
Moreover, since the method of patent document 1 uses the first several times for adjustment, there existed a problem which cannot respond when conveying to a different place each time.

  For this reason, conventional automatic cranes with different transport destinations each time or the position of the center of gravity of the suspended load are equipped with a deflection angle sensor and feedback of the deflection angle adds to the two-stage acceleration to improve the stabilization accuracy. As shown, the cost increased and the number of faults increased.

  The present invention has been developed to solve the above-described problems. That is, the purpose of the present invention is to prevent the crane from swinging, which can sufficiently reduce the remaining runout after the steadying without using the runout angle sensor even when the transportation destination is different each time and there is an error or change in the initial winding rope length. It is to provide a control method.

According to the present invention, a crane steadying control method for hanging a suspended load with a winding rope, traversing horizontally, and winding and lowering the winding rope,
A travel plan creation step for creating a travel plan for the transport crane by the input shaping method;
A transportation simulation step for obtaining a residual vibration width by performing a transportation simulation of the crane based on the travel plan,
An automatic operation control step of outputting an automatic operation work command when the residual vibration width is equal to or less than a predetermined threshold, traversing based on the travel plan, and transporting to a target position by hoisting and lowering the rope; Yes, and
In the transportation simulation step, the weight of the suspended load to be transported is changed, and the suspended load is transported with an actual crane at several weights in advance, and the transfer function of the actual crane operation with respect to the crane speed command is measured. Every
A crane steady-state control method characterized by measuring a weight at the moment of lifting a suspended load for actual transportation and obtaining a transfer function by interpolating two transfer functions close to the weight. Provided.

  According to a preferred embodiment of the present invention, in the travel plan creation step, the acceleration timing time of the crane is obtained from the movement distance, maximum acceleration, maximum speed, winding rope length and changes in winding rope length.

Also, the input shaping method is Zero Vibration and Derivative (ZVD) shaper,
Furthermore, it is preferable to obtain the acceleration timing time so as to satisfy the expressions (10) and (11).

  Further, in the transport simulation step, when the residual vibration width exceeds a predetermined threshold, a travel plan is prepared by adjusting acceleration timing until the residual vibration width becomes equal to or less than the threshold by vector synthesis on a phase plan view. Correct it.

According to the above-described method of the present invention, the modified ZVD shaper, which is a new anti-swaying control method that further modifies Zero Vibration and Derivative shaper (ZVD shaper), which is a kind of input shaping method, is used.
By constructing a model based on the target system using the modified ZVD shaper, it is possible to predict the overlapping of residual vibrations by a plurality of impulses and to set the residual vibrations to be eliminated.
In addition, although the ZVD shaper does not support changes in the winding length during traversal, the modified ZVD shaper of the present invention accelerates by obtaining the acceleration timing time so as to satisfy the expressions (10) and (11). Even when there is a change in the winding length during deceleration, the steady rest can be performed with high accuracy.

  Furthermore, in Patent Document 1, it was dealt with that the actual crane does not move according to the planned speed plan by performing numerical integration of the motion model while operating the crane. The weight of the suspended load is changed and the suspended load is transported in several weights in advance, and the transfer function of the actual crane motion with respect to the crane speed command is measured, and the suspended load is lifted for actual transportation. By measuring the weight at the moment and interpolating two transfer functions close to the weight with an appropriate interpolation method, the crane's dynamic characteristics can be accurately expressed without actually moving the crane. Based on this, a steady-state plan can be made.

Therefore, Patent Document 1 eliminates the restriction that required at least three times of transportation to perform steadying, and enables transportation to a different place every time.
Further, each time an actual suspended load is transported, the transfer function is identified each time, so that it is possible to cope with a change in dynamic characteristics caused by a decrease in motor capacity or an increase in friction of the drive system.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.

1. In the transportation of overhead cranes, container cranes, etc., there is a demand for a control technology that prevents the swinging while transporting to the destination in the shortest time.
However, if the height of the transport destination is different, the winding rope length changes and the swing cycle changes, so it is difficult to analytically plan the speed.
Therefore, the present invention pays attention to the input shaping method [Non-Patent Document 1], which is a feedforward control design method, and also utilizes a cable crane steady-state automatic adjustment technology [Non-Patent Document 2] that is in practical use. Therefore, we propose a method related to the steadying control of a crane in consideration of the change of the winding rope length.
Furthermore, a crane transportation simulation was set with reference to the conditions of the container crane actually used [Non-Patent Document 3]. As a result, it will be shown below that the anti-sway effect can be obtained even if the winding rope length includes an error.

2. Fig. 1 shows a crane motion model. In this figure, 1 is a suspended load, 2 is a winding rope for suspending the suspended load, 3 is a trolley truck, and 4 is a control device. The crane 5 includes a suspended load 1, a winding rope 2, a trolley cart 3, and a control device 4. The control device 4 may be mounted on the trolley carriage 3 or installed outside via a control line (not shown).
The trolley 3 has a function of hanging a suspended load 1 with a winding rope 2, traversing horizontally, and winding and lowering the winding rope 2. The control device 4 controls the hoisting and lowering of the trolley carriage 3 and the winding rope 2.
In FIG. 1, the coordinate system is fixed to the ground with the traveling direction of the trolley carriage 1 as x, and the deflection angle θ is fixed to the trolley 3 with the rightward direction being positive in the figure.

At this time, the equation of motion of the shake generated by the trolley carriage 3 is as shown in Equation (1), and the natural period T is as shown in Equation (2).
According to the method of the present invention, the crane is prevented from swinging by the winding rope length L (t) that suspends the suspended load 1 from the trolley carriage 3 and the acceleration d ² θ / dt ² (·· with θ) of the trolley carriage 3. Do.

3. Input Shaping Method (1) Zero Vibration (ZV) shaper
Input Shaping is a feedforward control design method [Non-Patent Document 1] and creates an acceleration plan based on a model.
ZV Shaper is a control method in which steadying is performed by superimposing residual vibration due to a plurality of impulses on a secondary system.
For the transfer function system shown in equation (2a), the residual vibration width V (ω, ζ) immediately after receiving n impulses having an integrated value A _i can be expressed by equations (3), (4), and (5). .

Here, i is the order number of the input impulses, A _i is the impulse, t _i is the acceleration timing time, ω is the natural angular frequency of the object, and ζ is the attenuation coefficient.

(2) Zero Vibration and Derivative (ZVD) shaper
In the ZVD shaper, the following constraint equation (6) is added to the ZV shaper in order to reduce the sensitivity of the residual vibration width V (ω, ζ) with respect to the natural angular frequency ω. As a result, equations (7) and (8) are obtained.

  However, if there is a winding operation in which the winding rope length greatly changes with ZVD shaper alone, it is difficult to obtain practically sufficient steady rest accuracy.

(3) Correction of ZVD shaper Therefore, in the present invention, the angular frequency ω of the crane is set as a time variable ω (t) defined by equation (9).

Further, in the present invention, in order to enable the corresponding Error of the center of gravity of the suspended load of the initial winding rope length L ₀ of the crane, put L (t), as in Equation (10). ΔL (t) is a change amount from L ₀ and is an amount that changes when the winding length is changed.

In the present invention, the residual vibration width V (ω, ζ) is replaced with V (L ₀ , ζ) to reduce the sensitivity of the residual vibration width V with respect to the initial winding rope length L ₀ . Equation (11) is used.

The conditions for establishing Expression (11) are Expression (12) and Expression (13).

As in equation (10), the winding for the rope length L (t) is divided into L ₀ and [Delta] L (t), the angular frequency ω which varies by winding the rope length changes remains in the formula, taking into account the change in ω The steady rest condition is met.

Since the crane is heavy and hardly attenuates, when the equations (12) and (13) are solved with the attenuation coefficient ζ = 0, the following results are obtained when n = 3.

When the angular frequency ω is constant, the impulse is A1: A2: A3 = 1: 2: 1, the acceleration timing time is t ₂ = π / ω, t ₃ = 2π / ω, and the equations (7), ( The conditions are the same as those obtained from 8), and are considered to be general expressions including the cases of Expressions (7) and (8).

4). Automatic adjustment of steady rest Actually, the system is nonlinear as shown in Equation (1), the input is not an impulse, the angular frequency ω changes while giving the input, there is a modeling error, etc. It is difficult to perform sufficient steadying only by satisfying the expressions (12) and (13).

Therefore, with the solutions of Equation (12) and Equation (13) as the initial state, automatic adjustment of the steady rest is performed by vector synthesis on the phase plane [Non-Patent Document 2]. As a result, even if there is an error in L _{0 according} to the equation (11), the influence on the residual vibration is small, so that the variation in the center of gravity of the suspended load to be carried can be allowed.

5. Simulation (1) A crane transportation simulation including the winding operation of the winding rope was performed with reference to the crane transportation simulation setting [Non-Patent Document 3].
The length of the winding rope is wound from 30 [m] to 10 [m] and then lowered to 30 [m]. Winding is performed while the crane is accelerating. For traversal, the maximum acceleration was 0.5 [m /], the maximum speed was 3 [m / s], and the moving distance was 45 [m].

FIG. 2 is a flowchart of a crane steadying control method according to the present invention.
The crane steady-state control method of the present invention is a crane steady-state control method in which the suspended load 1 shown in FIG. 1 is suspended by a winding rope 2, traversed horizontally, and the winding rope is wound and unwound. .
The crane steady-state control method of the present invention includes a travel plan creation step S1, a transport simulation step S2, a residual vibration determination step S3, an acceleration timing adjustment step S4, and automatic operation control steps S5 to S6. Each of these steps is performed by controlling the lengths of the trolley carriage 3 and the winding rope 2 by the control device 4 described above.

In the travel plan creation step S1, a travel plan for the transport crane is created by the Input Shaping method. In this travel plan creation step, the acceleration timing time of the crane is determined from the movement distance, maximum acceleration, maximum speed, winding rope length and changes in winding rope length.
Moreover, this Input Shaping method is Zero Vibration and Derivative (ZVD) shaper, and the acceleration timing time is obtained so as to satisfy the above-described equations (10) and (11).

In the transportation simulation step S2, a transportation simulation of the crane 5 is performed based on the travel plan to obtain a residual vibration width.
In the residual vibration determination step S3, the residual vibration width is compared with a predetermined threshold value.
When the residual vibration width exceeds a predetermined threshold value, in the acceleration timing adjustment step S4, the travel plan is corrected by adjusting the acceleration timing until the residual vibration width becomes equal to or less than the threshold value by vector synthesis on the phase plan view. To do.

When the residual vibration width is equal to or less than a predetermined threshold, in automatic operation control steps S5 to S6, an automatic operation work command is output, and the suspended load is hoisted and traversed horizontally based on the travel plan. Lower and transport to the target position.
Further, the transportation simulation step S2 is performed after lifting the suspended load and actually measuring its weight for transportation. For this reason, the weight of the suspended load to be transported is changed, the suspended load is transported at several weights in advance, and the actual transfer function of the crane operation with respect to the crane speed command is measured. The transfer simulation of S2 can be performed by interpolating two transfer functions close to the measured weight.

(2) Crane transport simulation execution procedure As described above, in the travel plan creation step S1, the crane acceleration timing by the modified ZVD is determined from the conditions such as the movement distance, the maximum acceleration, the maximum speed, and the change in the winding rope length and the winding rope length. Seeking time.
If the residual vibration width exceeds a predetermined threshold, acceleration timing is adjusted by vector synthesis on the phase plan view of θ and dθ / dt / ω shown in [Non-Patent Document 2] in the acceleration timing adjustment step S4. The time was adjusted so that at the end of crane acceleration and at the end of deceleration, the runout was 0 or below a predetermined threshold.

(3) to the simulation results Figure 3 shows the simulation results when there is no error in the initial winding rope length L _0. In this figure, the horizontal axis is time, the vertical axis is (A) is the traveling speed of the trolley truck 3 and the change speed of the winding length in the traveling plan obtained in the traveling plan creating step S1, and (B) is the transport simulation step. The travel position and winding length obtained in S2, (C) is the residual vibration width obtained in the transport simulation step S2. In the figure, t ₁ , t ₂ , t ₃ are acceleration timings, and t ₁ ′, t ₂ ′, t ₃ ′ are deceleration timings.
From this figure, when the suspended load is lifted, traversed horizontally, the suspended load is lowered and transported to the target position, the residual vibration width is 0.6 [mm], and there is no error in the initial winding rope length. It can be seen that there is almost no residual vibration. In addition, the transportation time was 26.33 [sec].

FIG. 4 shows a simulation result when the error of the initial winding rope length is 2.5%. In this figure, the horizontal axis is time, the vertical axis is (A) is the traveling speed of the trolley truck 3 and the change speed of the winding length in the traveling plan obtained in the traveling plan creating step S1, and (B) is the transport simulation step. The travel position and winding length obtained in S2, (C) is the residual vibration width obtained in the transport simulation step S2. In the figure, t ₁ , t ₂ , and t ₃ are acceleration timings, and t ₁ ′, t ₂ ′, and t ₃ ′ are deceleration timings.
In this example, the run-out simulation is performed by numerically integrating equation (1), and the traverse / winding speed pattern is given in the same manner as in FIG. 3, assuming that L = 1.025La (La is the true winding rope length). Numerical integration. As a result, in this figure, the residual vibration width is 4.7 [cm], which is a sufficiently small value for practical use.

6). As described above, the present invention has proposed an anti-sway control method using ZVD shaper correction and automatic anti-sway adjustment. Moreover, it was shown by the simulation of crane transportation that a practically sufficient steadying effect can be obtained even when the measured value of each winding rope length is + 2.5%.

  In addition, this invention is not limited to embodiment mentioned above, Of course, it can change variously in the range which does not deviate from the summary of this invention.

It is a movement model figure of a crane. It is a flowchart of the steadying control method of the crane by this invention. It is a simulation result when there is no error in the initial winding rope length. This is a simulation result when the error of the initial winding rope length is 2.5%. It is the schematic of the crane in which a traversing and winding operation | movement is possible. It is explanatory drawing of the Input Shaping method. It is explanatory drawing of a two-stage acceleration method. It is a flowchart of steadying control at the time of the automatic operation of the conventional crane. It is explanatory drawing of steadying control of patent document 1. FIG.

Explanation of symbols

1 Suspended load, 2 winding rope, 3 trolley truck, 4 control device, 5 crane

Claims (4)

A crane steadying control method for hanging a suspended load with a winding rope, traversing horizontally, and winding and lowering the winding rope,
A travel plan creation step for creating a travel plan for the transport crane by the input shaping method;
A transportation simulation step for obtaining a residual vibration width by performing a transportation simulation of the crane based on the travel plan,
An automatic operation control step of outputting an automatic operation work command when the residual vibration width is equal to or less than a predetermined threshold, traversing based on the travel plan, and transporting to a target position by hoisting and lowering the rope; Yes, and
In the transportation simulation step, the weight of the suspended load to be transported is changed, and the suspended load is transported with an actual crane at several weights in advance, and the transfer function of the actual crane operation with respect to the crane speed command is measured. Every
A crane steady-state control method characterized by measuring the weight at the moment of lifting a suspended load for actual transportation and interpolating two transfer functions close to the weight to obtain the transfer function .   2. The crane steady-state control method according to claim 1, wherein, in the travel plan creation step, an acceleration timing time of the crane is obtained from changes in travel distance, maximum acceleration, maximum speed, winding rope length and winding rope length. . The input shaping method is Zero Vibration and Derivative (ZVD) shaper,
Furthermore, the acceleration timing time is calculated so as to satisfy the expressions (12) and (13) of Equation 6.
Where i is the order number of the input impulses, A _i is the impulse, t _i is the acceleration timing time, ω is the natural angular frequency of the object, and ζ is the attenuation coefficient,
The crane steady-state control method according to claim 2, wherein:   In the transport simulation step, when the residual vibration width exceeds a predetermined threshold value, the travel plan is corrected by adjusting the acceleration timing until the residual vibration width becomes the threshold value or less by vector synthesis on a phase plan view. The crane steady-state control method according to claim 1.