JPH0761838B2 - Crane control method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a crane control method, and more particularly, to suppressing a shake of a load and shortening an arrival time while moving a suspended load to a target position. The present invention relates to a crane position and steady rest control that can be performed.

[Prior art]

The steady rest control system adopted in the rope suspension type crane is roughly classified into the following two types. One is a program control method in which the acceleration / deceleration pattern at which the swing of the suspended load stops at the target stop position is obtained in advance, and this is given programmatically. The other is by feeding back the swing angle of the suspended load. The feedback control method realizes steady rest.

The former grasps the characteristics of the suspended load in advance and predicts the movement of the suspended load so as to prevent shake at the target stop position. This is because the movement of the suspended load is generally characterized by the length of the suspension line, so the speed controller 31 and the crane driver 32 shown in FIG.
The program generator 33 is added to and. That is, the program generator 33 has an acceleration / deceleration pattern in which the swing of the suspended load stops at the target stop position depending on the suspension rope length and the moving distance, and the subtractor 34 that subtracts the detected speed signal from the speed command signal of the crane over time. It is designed to output to. A typical pattern output by the program generator 33 is, for example, as shown in FIG. The speed controller 31 compares the speed command signal output from the program generator 33 with the crane speed signal, and outputs a control signal to the crane driver 32 so that the crane speed follows the speed command. As can be seen from the above description, the program control method is essentially an open loop control method against load fluctuation.

The latter feedback control method described above has the configuration shown in FIG. That is, the difference between the current crane position and the target stop position is calculated and input to the position controller 41.
The position controller 41 outputs an output signal to bring the crane to the target stop position. The steady rest controller 42 outputs an output signal so that the swing angle of the suspended load becomes 0 degree. Position controller 41 with adder 43
The output signal of and the output signal of the steady rest controller 42 are added,
It is used as an operation signal for the crane driver 44. That is, it is the feedback control of the position and the deflection angle of the suspended load.

[Problems to be solved by the invention]

Although various methods have been announced by many studies for the above-mentioned program control method, since it is essentially open loop control, if the characteristics of the suspended load are insufficiently grasped or if disturbance is applied, the target There is a drawback that the steady rest accuracy becomes poor at the stop position. That is, the disturbance may be disturbance due to initial load shake and wind when hoisting a load, or in the case of a crane mounted on a ship, such as a tilt of the ship. Further, in the case of the deck crane shown in FIG. 16, since the length of the suspension rope 45 changes with the change in the depression angle φ of the crane, a complicated calculation is required in advance. Also, in the case of two-point suspension by the oncoming crane shown in FIG. 17, the movement of the suspended load 46 changes depending on the lengths of the two suspension lines 45a and 45b, the position of the center of gravity of the suspended load 46, the moment of inertia, and the mass. Therefore, it is impossible to determine the crane speed pattern by grasping the suspended load movement in advance. Therefore, the use of the program control method is limited depending on the operating conditions of the suspended load and the crane.

On the other hand, the feedback control method is more resistant to disturbance than the program control method because the deflection angle is fed back, and even if the target is not clear, control will not be impossible. Therefore, if it is difficult to grasp the movement of the suspended load in advance, such as with a deck crane or an oncoming two-point suspension crane, the feedback method will be adopted, but the position control system and steady rest control system will strongly interfere with each other, and convergence will occur. There is a problem of being late. For example, if both the position control system and the steady rest control system are strengthened, a load shake will occur backward while the vehicle is accelerating toward the target position, and the steady rest control will decelerate the crane. Also, if the steady rest control is made stronger than the position control in order to increase the effect of the steady rest control, the load shake occurs in the forward direction when decelerating near the target stop position, and the crane is There is also the property that the convergence of the position control deteriorates when moving forward. As can be seen from the above, if one of the steady rest control and the position control is strengthened, there is a problem that the convergence of the other control is impaired.

The present invention has been made in view of the above problems, and an object of the present invention is to reduce the mutual interference while allowing the steady-state control and the position control to work together in a feedback control system, thereby reducing the load shake during movement to a target position. It is an object of the present invention to provide a crane position and steady rest control method capable of suppressing the movement of the crane and shortening the arrival time.

[Means for solving problems]

The features of the present invention are as follows. First
According to the invention of claim 1, in a control method for a rope suspension crane that performs position control and steady rest control of a suspended load by a feedback control method, an evaluation function Ip including a detected deflection angle θ and a derivative value of the deflection angle
When the evaluation value Ipc becomes larger than the set value Ipo, the steady rest control gain Kf is increased and the position control gain Ki is decreased, and when the evaluation value Ipc becomes smaller toward the set value Ipo, the position control gain Steady stop control gain Kf with increasing Ki
Is to reduce.

In the second aspect of the invention, the steady rest control gain Kf is set small and the position control gain Ki is set until the suspended load starts moving and the distance to the target stop position is within the predetermined distance Lo. Largely set, until the suspended load reaches the predetermined distance Lo, detects the swing angle θ of the suspended load and calculates an evaluation function Ip including the swing angle θ and the differential value of the swing angle, The evaluation value Ipc is the set value Ipo
When it becomes larger, the steady rest control gain Kf is increased and the position control gain Ki is decreased, and when the evaluation value Ipc becomes smaller toward the set value Ipo, the position control gain Ki is increased and the steady rest control gain Kf is decreased. , When the suspended load enters the predetermined distance Lo and approaches the target stop position, the steady rest control gain Kf is set large and the position control gain Ki is set small, and the position control is performed by the swing angle evaluation value Ipc. Gain Ki and steady rest control gain K
This means that f and f are increased and decreased.

〔The invention's effect〕

In the first aspect of the invention, when the evaluation value becomes larger than the set value, the steady rest control gain is increased, and when the evaluation value becomes smaller, the position control gain is increased. Therefore, when the swing width of the suspended load is small, the position control gain is increased. The control can be prioritized, and the steady rest control can be prioritized when the shake width is large. Thereby, the interference between the steady rest control and the position control can be reduced, and it is possible to suppress the shake of the load until reaching the target stop position and shorten the arrival time.

In the second invention, in addition to the configuration of the first invention, until the suspended load reaches a predetermined distance before the target stop position,
The position control gain is set to a large value, and the steady rest control gain is set to a large value when the suspended load enters within the specified distance, so the movement is accelerated and the target stop is reached until the suspended load reaches the specified distance. In the vicinity of the position, the suppression of cargo shake is given priority. Therefore, the suspended load quickly moves to the vicinity of the target stop position, and the suspended load can be reliably unloaded in the short time in the vicinity of the target stop position.

[Examples] The present invention will be described in detail below based on examples. FIG. 1 is a configuration block diagram of an embodiment of the present invention, in which the position control and steady rest control of a suspended load are performed by a feedback control system. A crane driver 1 for instructing the operation of a drive device for turning a crane for moving a suspended load, raising or lowering or running, and hoisting and lowering a hoisting line, a position controller 2, and a steady rest controller 3 And an adder 4 are further provided, and a shake angle evaluation calculator 5 and a variable gain calculator 6 are further provided.
Is installed. This is because the shake angle evaluation calculator 5 calculates an evaluation function including the shake angle and the differential value of the shake angle based on the shake angle θ of the suspended load, and the variable gain calculator 6 performs control corresponding to the evaluated value. It is designed to determine the gain. In addition, the position controller 2 and the steady rest controller 3 use the normal proportional integral derivative control (PID control) or proportional derivative control so that the signals from the crane position detector 7 and the deflection angle detector 8 have desired values. (PD control) is adopted.

To briefly describe the idea of the present invention, an evaluation function of the swing angle θ of the suspended load is introduced, and when the evaluation value is high, that is, when the swing width is large, the gain of the steady rest control is increased, while the gain of the position control is decreased. By doing so, the steady rest is given priority. On the contrary, when the evaluation value is low, that is, the swing width is small, the gain of the steady rest control is reduced,
The position control is prioritized by increasing the position control gain. As a result, interference between the steady rest control and the position control is reduced, and in order to suppress the shake of the load until reaching the target stop position and shorten the arrival time, the control to be prioritized is enhanced.

Here, the evaluation function of the deflection angle θ will be described. Generally, the differential equation of load fluctuation is expressed by the following equation.

θ: Deflection angle of suspended load, v: Crane speed, l: Suspended rope length, g: Gravity acceleration On the other hand, it is assumed that feedback is ideally performed by the following equation as steady rest control.

The differential equation of Kf: proportional gain T _D : differential time constant θ is as follows.

At this time, the analytical solution of the vibration solution of θ is expressed by the following equation.

C ₁ , C ₂ : constants determined by the initial value Here, consider the following expression as the evaluation function Ip.

Substituting equation (4) into equation (5), A: It becomes a constant. Therefore, Ip is a monotonically decreasing function with respect to time, and its value is a coefficient corresponding to the amplitude of θ, as is clear from Eq. (4). Is proportional to the square of.

That is, if the equation (5) is adopted as the load shake evaluation function Ip, this Ip represents the square of the amplitude of the load shake angle at that time. Therefore, it is possible to judge the magnitude of the load deflection angle by this Ip. As a result, the gain of each control system may be determined using this evaluation function value.

As the evaluation function of the deflection angle, for example, Ip = θ ² (7) can be considered. This evaluation function has an extremely simple structure, and the evaluation value becomes smaller as the deflection angle θ becomes smaller.
However, it is impossible to distinguish between a state where the shake of the load is stopped and the shake angle is stable at 0 degrees, and a state where the shake angle temporarily becomes 0 degree while continuing the vibration. Therefore, if the gain of the steady rest control / position control is changed by this evaluation function, the following problems occur. That is, when the deflection angle temporarily becomes 0 degrees during the vibration of the suspended load, the evaluation value decreases, so the gain of the position control increases and the position control is prioritized. If the shake direction of B and the target position direction are opposite, the shake angle will be amplified by the position control. However, when the evaluation function is the expression (5), the differential value of the deflection angle θ has a non-zero value as long as it is vibrating even if the load deflection angle at a certain time is 0 degree. Does not become 0 unless the vibration stops. Therefore,
When the evaluation function of the expression (5) is adopted, the problem that occurs when the evaluation function of the expression (7) is adopted does not occur.

Returning to the description of the configuration again. The shake angle evaluation calculator 5 is as shown in FIG. 2, and calculates the evaluation function Ip including the shake angle θ detected by the shake angle detector 8 [see FIG. 1] and the derivative value dθ / dt of the shake angle. To do. There is a pseudo differentiator 9 in the circuit,
The differential signal dθ / dt of the deflection angle θ is output. Multiplier 10,11,1
2 is provided, Is calculated.

The constants used in the constant multipliers 13, 14, and 15 should be changed according to the suspension line length and the gain of the steady rest control system, as is clear from the equation (5). It has been confirmed by the study of the present inventors that there is no problem in practical use even if it is used as it is.

Evaluation value Ipc of the above evaluation function Ip added by the adder 16
Is larger than the preset value Ipo,
The variable gain calculator 6 increases the steady rest control gain Kf as indicated by the solid arrow M in FIG. 3 (a), and decreases the position control gain Ki as indicated by the solid arrow N in FIG. 3 (b). As a matter of course, when the evaluation value Ipc increases from the increased value toward the set value Ipo, the position control gain Ki is increased as indicated by the broken line arrow Q and the steady rest control gain Kf is decreased as indicated by the broken line arrow R. . The structure is as shown in FIG.
17 and a position control gain adjuster 18. That is,
It is possible to control the crane operation by centering the position control when the runout angle is small and by the steady motion control when the runout angle is large, by using both the adjusters 17 and 18. In, it is possible to avoid impairing the convergence of the other control.

The operation of the crane equipped with the control device having the above-described configuration will be described with reference to the flowchart shown in FIG. First, when the crane starts moving, the swing angle θ of the suspended load is detected momentarily by mechanical, optical or electromagnetic methods [Step 1, hereinafter referred to as S1], and the swing angle evaluation calculator is used. Input to 5. The deflection angle θ and the differential value dθ / d of the deflection angle θ from the passage of time during detection
t is calculated [S2], and the evaluation value Ipc of the evaluation function Ip is calculated [S3]. If the evaluation value Ipc is larger than the set value Ipo (S4), the steady rest control gain K / F 17 increases the steady rest control gain Kf, for example, in proportion to the increase of the evaluation value I pc, while the position control gain N / S 18 The position control gain Ki is decreased in proportion to the increase of the evaluation value Ipc [S5].
As a result, the steady rest control of the suspended load, in which the swing angle θ is large, is performed prior to the control of moving the suspended load to the target stop position. While the evaluation value Ipc is smaller than the set value Ipo, Kfo and Kio set from the beginning [see FIGS. 3 (a) and 3 (b)] are adopted [S6].

6 (a) and 6 (b) show a comparison of control effects between the method according to the present invention and the conventional method. It can be confirmed that the method according to the present invention is a solid line, and the steady rest control is prioritized over the position control when the swing angle θ is large. The conventional methods try to control the position and the shake at the same time and interfere with each other, and the convergence is delayed as shown by the broken line. FIG. 7 shows the locus of the suspended load when viewed from above, where (a) is based on the present invention and (b) is based on the conventional method. This example is a case where one long suspended load is handled by two cranes that move freely in the xy directions, and the target stop positions A and B are changed from the state with the initial load shake in the arrow U direction. This is the case when the suspended load is stopped. In addition, the solid line represents the locus of the suspended load end,
The broken line represents the posture of the suspended load at fixed time intervals. Incidentally, the above-mentioned FIG. 6 (b) is shown in FIG. 7 (a), (b).
Fig. 4 is a time series representation of the vertical direction of the left crane in Fig. As is clear from FIGS. 7 (a) and 7 (b), according to the control of the present invention, it is understood that the control is satisfactorily performed in less than half the time. Therefore, according to the present invention, while the steady rest control and the position control work together in the feedback control method, mutual interference is reduced, and the load shake is suppressed and the arrival time is shortened until reaching the target position and stopping. Can be achieved.

FIG. 8 is a block diagram of a variable gain calculator according to a different invention. As shown in FIGS. 9 (a) and 9 (b), the crane has reached the target position while moving toward the target position. The corresponding steady rest control gain Kf and position control gain Ki are changed depending on time. This enables the steady rest control to act particularly intensively near the target position. Therefore, depending on whether the distance to the target stop position where the suspended load starts moving falls within a predetermined distance Lo, a steady rest control gain changer 19 for changing the steady rest control gain Kf and a position control gain Ki are set. A position control gain changer 20 for changing is provided. Then, until the distance to the target stop position of the suspended load reaches the predetermined distance Lo, an evaluation function Ip including the deflection angle of the suspended load and the differential value of the deflection angle is calculated, and the evaluation value Ipc is set. When it becomes larger than the value Ipo, as shown in FIGS. 10 (a) and 10 (b), the steady-state control gain increase amount determiner 21 that increases the steady-state control gain Kf and the position control gain decrease that decreases the position control gain Ki. There is a quantity determiner 22. After the steady rest control gain changer 19 and the position control gain changer 20 described above, an adder 23 and a subtractor 24 are interposed, and the respective control gains Ki and Kf are set to the first value.
It can be changed as shown in Fig. 1 (a) and (b). As a result, when the crane is far away from the target stop position, the steady rest control gain is small and the position control gain is large, but even in such a case, the steady rest control is strengthened as necessary to move the crane. It is possible to correct the posture of the suspended load while suppressing the harmful effects of accelerating the load.

The operation of the control device having such a configuration will be described with reference to the flowchart shown in FIG. The suspended load is lifted and the crane starts moving. The travel distance of the crane is detected momentarily by the crane position detector [S21] and input to the variable gain calculator. If the detected distance Lr to the target stop position has not reached the preset distance, for example, the point Lo leaving a distance of 10% to the target stop position [S22], the steady rest control gain becomes Kfo In addition to being set to a small value, the position control gain is set to a large value Kio [see FIGS. 9 (a) and 9 (b)] [S2
3]. Then, until the suspended load reaches the predetermined distance Lo, the swing angle θ of the suspended load is detected [S24], and the swing angle θ is detected.
And the evaluation function Ip including the derivative of the deflection angle is calculated [S2
Five〕. When the evaluation value Ipc becomes larger than the set value Ipo [S2
6), the steady rest control gain Kf is increased by ΔKf calculated by the steady rest control gain increase amount determiner 21, while the position control gain Ki is reduced by ΔKi calculated by the position control gain decrease amount determiner 22. [S27]. As a result, until the suspended load reaches the predetermined distance Lo, control is mainly performed to increase the moving speed, and the steady rest control is performed only when a swing angle large enough to be corrected occurs during that period. .

When the crane continues to move and comes within the predetermined distance Lo of the target stop position [S22], the steady rest control gain is gradually increased according to the distance to the target stop position, and the position control gain is reversed. It is set to a small value [see FIGS. 9 (a) and 9 (b)] [S28]. As a result, the moving speed at the remaining distance decreases, but the shake of the load is suppressed, so that the suspended load can be accurately lowered to the target stop position.

[Brief description of drawings]

FIG. 1 is a block diagram of the configuration of feedback control according to the present invention, FIG. 2 is a block diagram of a deflection angle evaluation calculator, and FIG.
(A) and (b) are increase / decrease diagrams of the steady rest control gain and the position control gain with respect to the evaluation value, FIG. 4 is a block diagram of the variable gain calculator, FIG. 5 is a flowchart of increase / decrease of control gain, and FIG. (a) and (b) are time charts comparing the deflection angle and the convergence of the suspended load position with the conventional feedback control, and FIGS. 7 (a) and (b) show the case of two-point suspension by two cranes. FIG. 8 is an explanatory view of a convergence situation of position control to which the present invention and conventional feedback control are applied. FIG. 8 is a block diagram of a variable gain calculator in a different invention.
FIGS. 10 (a) and 10 (b) are change diagrams of the control gain according to the moving distance of the suspended load, FIGS. 10 (a) and 10 (b) are diagrams of determining the increase amount or decrease amount of the control gain when there is a shake of the load, 11 (a) and 11 (b) are increase / decrease diagrams of the steady rest control gain and the position control gain with respect to the evaluation value, and FIG.
FIG. 13 is a block diagram of a program control system in the prior art, and FIG. 14 is a time chart showing the output of the crane speed from the program generator in the program control system.
FIG. 15 is a block diagram of a feedback control system in the prior art, FIG. 16 is a schematic diagram of a deck crane, and FIG. 17 is a schematic diagram of an oncoming two-point hanging deck crane. θ: deflection angle, Ip: evaluation function, Ipc: evaluation value, Ipo:
… Set value, Kf… steady rest control gain, Ki… position control gain.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yoichi Komoriya Yoichi Komoriya, 234 Matsumoto, Higashiya-cho, Nishi-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries, Ltd. Nishi-Kobe factory (56) Reference JP-A-60-44489 (JP, A) Public Sho 61-17979 (JP, B1)

Claims (2)

[Claims] 1. A control method for a rope suspension crane, which performs position control of a suspended load and steady rest control by a feedback control method, calculates an evaluation function including a detected swing angle and a differential value of the swing angle, and evaluates the evaluation function. When the value becomes larger than the set value, the steady rest control gain is increased and the position control gain is decreased, and when the evaluation value becomes smaller toward the preset value, the position control gain is increased and the steady rest control gain is decreased. A method of controlling a crane characterized in that 2. A rope suspension crane control method for performing position control and steady rest control of a suspended load by a feedback control method, wherein the suspended load starts moving and the distance to its target stop position is within a predetermined distance. , Set the steady rest gain small and set the position control gain large, and detect the deflection angle of the suspended load until the suspended load reaches the predetermined distance. When the evaluation function including the derivative value of the deflection angle is calculated, and the evaluation value becomes larger than the set value, the steady rest control gain is increased and the position control gain is decreased, and when the evaluation value becomes smaller toward the set value, the position Increase the control gain and decrease the steady rest control gain, and increase the steady rest control gain when the suspended load enters within the predetermined distance and approaches the target stop position. The method of the crane, characterized in that with previously set may be set smaller position control gain, and to increase or decrease the control gain steady rests and the position control gain by deflection angle evaluation value.