JPH0742072B2 - Steady stop control device for suspension crane - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steady rest control device in a suspension type crane for steady rest of an object to be transported during constant speed transportation.

[Conventional technology]

For more information on the conventional steady rest control method for cranes, refer to “International Conference on Microcomputer Applications, '80, (4) Steady rest control for cranes using a microprocessor, P12.
1 ~ P130 "and" 24th Automatic Control Joint Lecture (2012) One method of steady rest of hoisting traveling type overhead crane (1981)
November) ”. As a model of a suspension crane, consider a simple pendulum model as shown in FIG. In the figure, 1 is a trolley, and 2 is a suspended load suspended from the trolley 1 by a rope 3. If the gravitational acceleration is g and the acceleration of the trolley 1 is α, the swing angle θ of the suspended load 2 is given by the following equation.

l + 2 + gθ = -α (1) where is the angular velocity Is the angular acceleration Is the winding speed of rope 3 When the acceleration α is a constant value (α ₀ ) and the rope length of the rope 3 is a constant value (l ₀ ), the second term is omitted from the equation (1) and the pendulum motion is l ₀ + gθ = Α ₀ ·························· (2) is the step response of the non-damped one degree of freedom. When this result is represented by the phase plane, the points (-) shown in FIG.
It becomes a circular orbit centered around α / g, 0) with a radius of α / g, and if the acceleration is stopped at the time when it makes a full turn, the trolley 1 can swing while running at a constant speed.

The steady rest control system for a suspension crane using this principle is roughly classified into a control system for accelerating and decelerating a trolley in an integral multiple of the vibration cycle determined by the rope length of the suspended load shown in FIG. , A control method derived from the shortest time control problem that is formulated so that only the acceleration / deceleration section of the trolley shown in FIG. 7 is set to the maximum trolley speed at the end of the acceleration section and the load deflection angle is set to zero. Is proposed.

Here, in FIGS. 6 and 7, V is the speed of the trolley, t is the time, αmax is the maximum acceleration of the trolley, α is the acceleration of the trolley, and Vmax is the maximum speed of the trolley.

6 (a) and 7 (a) show the velocity pattern of the trolley, FIG. 6 (b) and FIG. 7 (b) show the reference acceleration input of the trolley, and FIG. ) And FIG. 7 (c) are diagrams showing the phase plane locus of the load swing, respectively. The velocity, acceleration input of these trolleys and the phase plane trajectory of the load swing are the rope length, the allowable maximum velocity of the trolley, and the maximum allowable acceleration. ， It is set only when time is used as the evaluation standard from the distance traveled.

Next, the operation will be described. First, in the case of the control method shown in FIG. 6, the vibration cycle of the suspended load Is determined only by the rope length l, the control method is simple, and the change in acceleration is small, so that the load on the speed control system is small. Then, when the trolley is accelerated in the acceleration section, the suspended load starts oscillating around (-α / g), After 2 seconds the load shake becomes zero (where Is a natural frequency, and n is a natural number). Next, in the constant velocity section, the acceleration becomes zero and does not affect the vibration. Therefore, by selecting the acceleration / deceleration time as an integral multiple of the vibration cycle, the load shake can be made zero when the trolley stops.

Further, in the case of the steady rest control system of the suspension crane shown in Fig. 7, the acceleration / deceleration is repeated for the trolley at the acceleration switching time determined by the crane traveling conditions such as the rope length, the maximum allowable acceleration and the maximum allowable speed. Thus, control is performed so that the load shake is zero at the end of the acceleration section and the trolley speed is the maximum speed. Here, β / ω and δ / ω are acceleration times of the trolley in the acceleration section, and γ / ω are deceleration times of the trolley in the acceleration section.

Therefore, as seen in the phase plane orbit of FIG. 7 (c), the first acceleration from the origin O draws a circular orbit centered at (-αmax / g) and advances to point A, and at the next deceleration (αmax / g). Proceed on a circular orbit centered at g) to reach point B. Then, by the second acceleration, the phase plane origin O is reached. As a result, the vibration of the load becomes zero when the maximum speed is reached, and no vibration occurs because the acceleration input is zero in the low speed section thereafter. Further, also in the deceleration section, it is possible to reduce the shake of the load to zero by performing the same control as in the acceleration section.

However, any of the above-described conventional steady rest control systems for suspension type cranes is effective when it is assumed that the rope length during steady rest control is always constant.

Next, let us consider the pendulum luck movement when considering changes in the rope. When the trolley is accelerated while the acceleration α is constant (α ₀ ) during the constant-speed winding (= −C), the equation (1) becomes (l ₀ −Ct) −2C + gθ = −α ₀ (3) (here Where l ₀ is the initial length of the rope) and the negative damping is 1
It becomes a step response of the system of degrees of freedom, and its phase plane becomes spiral and diverges as shown in FIG. 5 (b). Therefore, the acceleration α is gradually increased with time t (α = α ₀ + α ₁ t)
It has been proposed that the swing of the trolley during constant speed traveling can be taken by setting (however, α ₀ and α ₁ are non-zero values).

[Problems to be solved by the invention]

Since the steady rest control system in the conventional suspension crane is configured as described above, complicated calculations must be performed and a high-level electronic computer is required, so a microcomputer level mounted on the crane is required. It is difficult to execute this calculation by the controller of, and there is a problem that it is very difficult in terms of price to adopt a high-level electronic computer on a solid line.

The present invention has been made in order to solve the above-mentioned problems, in which the steady rest pattern is fixed, the change in the length of the linear body is made uniform by the average value, and the acceleration / deceleration switching corresponding to the length of the linear body is performed. It is an object of the present invention to obtain a steady rest control device for a suspension crane in which time is held as a table in a controller on the crane and steady rests can be achieved only by table search in actual machine operation.

[Means for solving problems]

The steady rest control device in the suspension crane according to the present invention averages the linear bodies when changing the length of the linear bodies during the transportation of the transported object suspended from the traveling body by the linear bodies. The average linear body length, which is the length, is derived from the function for calculating the average linear body length preset by the linear body length calculation circuit and the winding start position of the transported object to be substituted into this function, and the average linear body length is calculated. Acceleration period and deceleration period read from the output of the average linear body length calculation circuit from the data table section that is stored in advance as a data table by correlating the period for accelerating and decelerating the traveling body and the deceleration period according to the body length and speed pattern. According to the above, the crane control system controls the speed of the traveling body before reaching a constant speed.

[Action]

The steady rest control device in the suspended crane according to the present invention derives the average length of the linear body by the average linear body length calculation circuit even when the length of the linear body changes to determine the length of the linear body. It is fixed, the acceleration period and deceleration period corresponding to this average linear body length are read from the data table section, the speed pattern is determined, the speed of the traveling body is controlled according to this speed pattern, and the speed of the traveling body is controlled at a constant speed. The shake of the carrier is controlled to zero.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a steady rest control device for a suspension crane for explaining an embodiment of the present invention. In the figure, 1 is a trolley as an example of a traveling body, 2 is a bucket as an example of a part of a transported body,
3 is a rope as an example of a linear body for suspending the bucket 2, 11 is a hoisting drum provided in the trolley 1 for hoisting or unwinding the rope 3, 12 is an electric motor, and a speed reducer 13 The hoisting drum 11 is driven via. 14 is a finger speed generator directly connected to the electric motor 12, 15 is a synchro oscillator mounted on the shaft of the hoisting drum 11, 16 is an output of the finger speed generator 14 as a feedback signal, and outputs a drive signal to the electric motor 12. A hoisting drive device 17 is a synchro-digital converter, and the synchro signal from the synchro oscillator 15 is used as a digital position signal. 21 is a traverse drum for traversing the trolley 1 in a predetermined direction via a rope 21A annularly connected to the trolley 1,
Reference numeral 22 denotes an electric motor, which drives the traverse drum 21 via the speed reducer 23. Reference numeral 24 is a finger speed generator directly connected to the electric motor 22, and 25 is a synchro oscillator mounted on the axis of the traverse drum 21. 26 uses the output of the finger speed generator 24 as a feedback signal,
A transverse drive device that outputs a drive signal to the reference numeral 27, a synchro-digital converter 27, which uses the synchro signal from the synchro oscillator 25 as a digital position signal.

Reference numeral 30 denotes a programmable controller which inputs an operation command S, a position signal indicating the position of the bucket 2 from the synchro-digital converter 17 and a position signal indicating the position of the trolley 1 from the synchro-digital converter 27, An ON / OFF command is given to the hoisting drive device 16 according to the set program, and an analog signal according to the operating speed pattern is given to the traverse drive device 26. The programmable controller 30 is composed of the components described below. Reference numeral 31 is a command circuit which receives the operation command S and commands the final moving position to the hoisting device and traverse device. 32 and 33 receive the position command from the command circuit 31 and from the synchro-digital converters 17 and 27. Input the position signal for each feedback,
It is a position servo function circuit that constitutes a position servo function.
34 is a linear function equation for obtaining the average rope length la preset by the command from the command circuit 31 and the average rope length la is calculated using the hoisting start position, and the position signal from the synchro-digital converter 17 is used. To calculate the average rope length of the rope 3 and output it to the data table section 35 described later (average linear body length calculation circuit), and 35 is the average rope length and the switching time ( Β in Fig. 7 (a)
/ Ω, γ / ω). Reference numeral 36 denotes a traverse operation pattern generation circuit, which inputs and stores the switching time from the data table section 35 and also inputs a final movement position command from the command circuit 31 to execute a traverse operation speed pattern (see FIG. ) Reference) is output to the traverse drive device 26. Since the operation pattern of the hoisting drive device 16 is always constant, the output from the position servo function circuit 33 is only an ON / OFF command.

In this embodiment, the steady rest speed pattern shown in FIG. 7 (a) is used. Further, FIG. 2 (a) shows the average value la of the rope length l ₀ of the rope 3 before the start of acceleration of the trolley 1 and the rope length l ₁ at the completion of acceleration in that case, for fixing the rope length. FIG. In FIG. 2 (a), if the hoisting speed of the rope 3 is represented by C (constant), the relational expression l = l ₀ -Ct holds. As a result, it can be seen that the phase plane becomes as shown by the broken line in FIG. 2 (b) and returns to the approximate origin.

Next, a method of determining the switching time in the steady rest speed pattern of FIG. 7 (a) will be described. In FIG. 7 (a), assuming that the maximum acceleration of the trolley 1 in the acceleration section is constant as αmax and the switching time is β / ω, γ / ω, δ / ω, (International Conference on Microcomputer Applications, '80, Micro Crane steady control using a processor: Satoru Fujita et al.) Becomes However, Vmax is the maximum speed of the trolley 1 in the constant speed section.

Here, the rope length 1 is constant, but the above equation is satisfied even if the average rope length la is obtained and the rope length is fixed as described above. Further, if n = 1 and β = δ, (4)-
Equation (8) is Becomes

Since equations (9) and (10) are relational expressions of β, γ, l,
Eliminating the term γ from equations (9) and (10) The relational expression between and Is derived, the term of β is deleted from the equations (10) and (13), and the relational expression between γ and l, Is guided. However, F (l) is a function having l as a variable.

From equations (13) and (14), the values of the switching times β / ω and γ / ω for each value of the rope length 1 are obtained in advance. These stopped values are the rope length l with the average rope length la Is stored in the data table unit 35 in advance as a table.

FIG. 3 (a) shows a locus along which the center of gravity of the bucket 2 moves when the apparatus shown in FIG. 1 is applied to an unloader. In the figure, 2 is a bucket, 3 is a rope, 40 is a ship hatch, and 41 is an ore surface made of ore loaded in the ship hatch. The inclination of the path of the bucket 2 is determined by the maximum hoisting speed C of the rope 3 and the maximum traverse speed Vmax of the trolley 1. The case where the bucket 2 grabs the ore at the R point on the ore surface 41 in the figure, and then the rope 3 starts to be wound, and the traverse operation is performed at the P ₀ point above the R point will be described. Since the trolley 1 is accelerated by the velocity pattern as shown in FIG.
Traverses the path indicated by the broken line in the figure and completes acceleration (Q ₀ point)
The amount of traverse up to Vm is Vm when Ta is the time in the acceleration section.
It becomes ax ・ Ta / 2. The amount of movement in the hoisting direction of the bucket 2 due to hoisting of the rope 3 during that time is C · Ta. However, the route that actually wants to pass through the bucket 2 is the shortest route shown by the solid line in the figure, and passes through Q ₁ . Therefore, if the acceleration start position is moved from the point P _{0 to the} point P ₁ and passes through the path indicated by the alternate long and short dash line in the figure, the shortest path is obtained. Also,
At this time, the distance between the P ₀ point and the P ₁ point is C · Ta / 2, which is half the amount of movement of the bucket 2 in the winding direction during traverse acceleration. That is, it can be seen that P ₀ point is the average rope length during transverse acceleration. Generally, when the route of the bucket 2 is determined by modeling, a straight shortest route (P _{0 to} Q ₁ route) shown by a solid line that does not collide with the corner of the land side hatch of the ship is selected. This path is a linear function formula, and can be easily determined by modeling as long as the position in the traverse / winding direction is determined. By substituting the traversing position where the winding is started into the functional expression of the determined route, P ₀ point can be obtained, and the average rope length la can be obtained from the P ₀ point. This calculation is performed after the programmable controller 30 receives the operation command S,
This is executed by the average rope length calculation circuit 34.

FIG. 3 (b) shows the path of the bucket 2, in which 42 is a hopper on land and 43 is a pedestal supported on land for traveling the trolley 1 on a predetermined track surface. The route of bucket 2 is R → P ₁ → P ₂ → P ₃ → P ₄ → P ₅ → P ₆ → P ₇ , but points P ₃ and P ₄ are the same point. Winding a and traverse a indicate the hoisting speed and traverse speed with respect to the position when the bucket 2 follows the route of R → P ₁ → P ₂ → P ₃ . The pattern of the horizontal line a corresponds to the speed pattern of FIG. roll
b and traverse b respectively show the unwinding speed and the traversing speed of the bucket 2 on the return path.

Next, the operation of this embodiment will be described. Operation command S
The average rope length calculation circuit 34 of the programmable controller 30 that received the above calculates and outputs the average rope length la as described above. The data table section 35 has an average rope length la.
Switching time β / ω (=
The value of δ / ω) and the value of γ / ω are sent to the driving pattern generation circuit 36, where the driving pattern generation circuit 36 stores these values.

Next, the programmable controller 30 transfers R to bucket 2.
The hoisting drive device 16 is controlled so that the ore 41 is caught at the point and the bucket 2 is raised. After the time point when the bucket 2 reaches the point P ₁ , the steady rest control is performed according to the speed pattern shown in FIG. 7 (a). The operation pattern generation circuit 36, which has input a traverse operation start command from the command circuit 31 via the position servo function circuit 32, traverses an analog signal for accelerating the trolley 1 at the acceleration αmax for the stored switching time β / ω. Supply to the device 26. As a result, the transverse drive device 26 receives the feedback signal from the finger speed generator 24,
The traverse drum 21 is rotated via the electric motor 22 and the speed reducer 23 to accelerate the trolley 1 for the switching time β / ω.

When the switching time β / ω has passed, the operation pattern generation circuit
Reference numeral 36 supplies the analog signal for decelerating the trolley 1 at the acceleration -αmax for the stored switching time γ / ω to the transverse drive device 26. As a result, the trolley 1 is decelerated for the switching time γ / ω in the acceleration section. Next, when the switching time γ / ω has elapsed, the operation pattern generation circuit 36 traverses the analog signal for accelerating the trolley 1 again at the acceleration αmax for the stored switching time δ / ω (= β / ω). Supply to the drive unit 26. As a result, the trolley 1 is accelerated again for the switching time δ / ω (= β / ω). When this time δ / ω (= β / ω) has elapsed, the bucket 2
Is at the position of Q ₁ and enters the constant speed section shown in FIG. 7 (a), the operation pattern generation circuit 36 sets the trolley 1 to the constant speed Vm.
Output an analog signal to move with ax. As a result, the trolley 1 moves at a constant speed Vmax. In this way, when the operation of the suspension crane shifts from the acceleration section to the constant speed section, the swing of the bucket 2 is controlled to be zero.

On the other hand, the hoisting drive device 16 receives the feedback signal from the finger speed generator 14 by the ON signal from the position servo function circuit 33, and while the hoisting drum 11 passes the rope 3 through the electric motor 12 and the speed reducer 13. Is continuously wound at a constant speed C, and when the bucket 2 reaches point P ₂ in the constant speed section, the winding is stopped. Synchro oscillator when winding this rope 3
The average rope length calculation circuit 34, which receives the position signal from 15 through the synchro-digital converter 17, calculates the average rope length la based on the position signal immediately after winding. The calculated average rope length la is given to the data table section 35, and the actual switching time β / ω /,
γ / ω is transmitted. These updated values are stored by the operation pattern generation circuit 36 in the same manner as described above, and are used when the same operation is performed next time.

When the trolley 1 reaches the boundary position between the constant speed section and the deceleration section, this position signal is sent from the synchro oscillator 25 to the synchro-digital converter 27, and further to the operation lane generation circuit 36 via the position servo function circuit 32. Since it is input, the operation pattern generating circuit 36 decelerates the bucket 2 with respect to this input. In this way, the operation opposite to the above acceleration section is performed in the deceleration section shown in FIG. 7 (a).

At the end of deceleration, bucket 2 is at the position of point P ₃ , where traverse operation is stopped by the operation of servo function circuit 32,
The ore in the bucket 2 is transferred to the hopper 42. Then trolley 1 is moved in the opposite direction to what it was
The operation reverse to the above operation is performed. That is, the bucket 2 follows the route of P ₃ → P ₄ → P ₅ → P ₆ → P ₇ and reaches the ore surface 41. The speed of the bucket 2 with respect to the position of the bucket 2 at this time is shown in winding b and traverse b of FIG. 3 (b). Incidentally, here, the bucket 2 is unwound in the path of P ₅ → P ₆ → P ₇ . As described above, when the average rope length does not change from this time and the same operation is repeated, the operation pattern generating circuit 36 stores the switching time β / ω
Use /, γ / ω. Further, in the next operation, when the crane is operated by changing the average rope length from this time, the average rope length is calculated by the average rope length calculation circuit 34 using the linear function or the like as described above. To be done.

The average rope length may be calculated by the average rope length calculation circuit 34 by preparing a number of setting values to be substituted for the linear function, selecting an appropriate setting value by the operation command S, and Of course, not only one linear function but also a plurality of types of linear functions corresponding to various traverse speeds and hoisting speeds may be prepared and selected by the operation command S.

Further, in the above embodiment, the embodiment with the speed pattern of FIG. 7 (a) is shown, but as can be judged from the explanation,
Any speed pattern can be applied as long as the horizontal movement amount during acceleration / deceleration of horizontal movement satisfies the relationship of V · Ta / 2.

〔The invention's effect〕

As described above, according to the present invention, the complicated steady rest algorithm is simplified by the average rope length, and the switching time at the time of acceleration / deceleration is held in the on-board controller as a data table corresponding to the average rope length. Since it is configured so that after the simple calculation, the steady can be performed by searching the data, the device can be made inexpensive, and an effect that can be well linked to the route setting control of the suspended load can be obtained.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing a control device in a suspension crane for explaining an embodiment of the present invention, and FIG. 2 (a) is a diagram showing a concept of an average rope length according to an embodiment of the present invention. FIG. 2 (b) is a diagram showing a phase plane trajectory when the average rope length is approximated to a fixed rope length, and FIG. 3 is a diagram showing a suspended load path according to an embodiment of the present invention, and FIG. Is a conceptual diagram of load swing of a suspension crane, FIG. 5 is a diagram showing respective phase plane trajectories in acceleration sections during constant acceleration and variable acceleration, and FIGS. 6 (a) to 6 (c) and FIG. (A) ~
FIG. 7C is a diagram showing the respective phase patterns of the velocity pattern, the reference acceleration input, and the shake of the load. In the figure, 1 is a trolley, 2 is a bucket, 3 is a rope,
11 is a hoisting drum, 12 and 22 are electric motors, 13 and 23 are reducers, and 14 and 2
4 is a finger speed generator, 15 and 25 are synchro oscillators, 17 and 27 are synchro-digital converters, 16 is a hoisting drive device, 21 is a traverse drum, 26 is a traverse drive device, 30 is a programmable controller, 32 and 33. Is a position servo function circuit, 34 is an average rope length calculation circuit, 35 is a data table section, and 36 is an operation pattern generation circuit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A linear object for hoisting and lowering at a constant speed a transported object which is driven and controlled by a crane control system for suspending crane control and can be transported to a traveling object capable of traveling on a predetermined track surface. Deflection in a suspension crane that suspends and conveys the transported object at a constant speed of the traveling object by driving and controlling the speed of the traveling object in accordance with a predetermined speed pattern having a relationship of speed with time. In the stop control device, an average linear body length which is an average length of the linear bodies when the length of the linear bodies from the traveling body to the transported body is changed during the transportation of the transported body. An average linear body length calculation circuit for deriving the average linear body length using a preset function for calculating the above and a winding start position of the transported object to be substituted into this function, and an average linear body length. And the speed A data table section that is stored in advance as a data table by associating an acceleration period and a deceleration period for accelerating and decelerating the traveling body according to a turn, and the fixed period according to the acceleration period and the deceleration period read from the data table unit. A steadying control device for a suspended crane, comprising: an operation pattern generation circuit that outputs a speed signal of the traveling body before reaching a speed.