KR100263874B1 - Controlling method of crane fork - Google Patents

Abstract

PURPOSE: A method is provided to obtain an optimal fork control path automatically depending on outer condition change of fork. CONSTITUTION: A periodic signal required for sampling is input through a main periodic timer. A reference position according to moved amount of target speed is established. Speed of a fork from a difference between a speed reference position and a previous speed reference position is set. The speed established is output through an inverter(60) and is decided to be bigger than zero. In case of less than zero, a flag is finished. The speed reference position setting is divided into a reference position setting process to a target position and a process of obtaining a mean for each FIFO value corresponding to the preset reference position. In case reference position is bigger than a target position, the reference position is changed to set a target position to a new reference position. For obtaining a new speed different from a signal newly fed by a main periodic timer, a value of a previous speed reference position is newly established as a value of speed reference position.

Description

Fork control method of crane for automobile warehouse

Figure 1 (a) is a schematic diagram showing an example of an internal structure of an automobile warehouse, a diagram (1) (b) a rack structure, and Figure 1 (c) a crane for transporting and positioning cargo in an automated warehouse.

2 is a graph showing the speed change of the fork over time to obtain the optimum control path of the fork.

3 is a block diagram showing a system for obtaining an optimal control path.

Figure 4 is a sensor attachment diagram showing a fork mechanism diagram and each sensor attached state.

5 is a flowchart showing steps for obtaining an optimum position control path of a fork.

6 is a graph showing the speed change with time and one data of a program simulation for performing the flowchart shown in FIG.

* Explanation of symbols for main parts of the drawings

40: main board 50: input / output board

60: inverter 70: drive unit

80: fork position / limit detection unit

The present invention relates to a method for controlling a fork of an automated warehouse crane for storing and storing an object in an automatic warehouse, or taking out a loaded object. Specifically, the present invention relates to measuring the limit of movement of a fork and automatically responding to changes in the length of the fork. The present invention relates to a fork control method of an automated warehouse crane that generates an optimal fork control path and executes fork control.

Referring to FIG. 1 (a), the conventional automated warehouse can transfer the cargo to and from the crane 10, the rack structure 20 for loading the cargo, and the warehouse. Work table 22 to perform the work so as to, and the rail 12 to guide the crane 10 is provided with a transfer.

Referring to FIG. 1 (b), the rack structure 20 is coupled to form a frame with a plurality of vertical beams 24 arranged in a vertical direction and a plurality of horizontal beams 26 arranged in a horizontal direction. . The cargo 30 is loaded in the coupling space between the vertical beams 24 and the horizontal beams 26 that are combined as described above. Each vertical space supports the cargo 30 and the fork space 27 through which the fork of the crane (first (a)) can freely enter and exit the cargo 30 is secured. A cargo support 28 provided at a predetermined height of 24 is provided.

Referring to FIG. 1 (c), the crane 10 includes a fork (not shown) for supporting cargo, a lifting body 14 for moving the fork to a layered rack structure space, and the lifting body ( 14 consists of an upper support 15 and a vertical support 16 for supporting 14, a moving body 17 for moving the entire crane 10 along the rail 12, and a controller 18 for controlling movement and lifting. have.

Therefore, when the cargo is transferred from the outside of the warehouse to the work platform 22, the crane 10 is moved by the movable body 17 at the work bench 22 position, and the cargo transported by the lifting body 14 ( The lower part of 30) is supported by a fork. The supported cargo 30 is transported to the rack structure loading position along the rail. The crane 10 transferred to the rack structure at the loading position by the moving body 17 is stopped, and the lifting body 14 is placed on the cargo support 28 at the desired loading position by adjusting the height. Through micro-leveling, the fork is released from the support of the cargo. Of course, in the case of transporting the cargo loaded on the rack structure to the outside of the warehouse proceeds to the path opposite to the path for loading the cargo on the rack structure as mentioned.

In this case, the operator figured out the control path by calculating the length of the fork, the moving speed of the crane driven by the controller, the high speed and automatic moving time of the crane, and the mechanical design value for the moving length. In addition, a method of inputting and controlling the control path to the inverter is used to output the calculated control path.

In the case of using such a control method, in order to find the optimal control path, there is an error between calculation and execution, and the repeated execution error must be repeated. In addition, it was troublesome to repeat the process mentioned for application in a warehouse with a different structure.

Accordingly, an object of the present invention is to provide a method for automatically obtaining an optimal fork control path according to a change in external conditions of a fork, which is devised to overcome the above-described points.

In order to achieve the above object, the present invention comprises the steps of inputting a periodic signal required for sampling through a fixed period timer, setting a reference position according to the target speed movement amount, setting a speed reference position, speed Setting the speed of the fork from the difference between the reference position and the previous speed reference position; outputting the set speed through the inverter; determining whether the set speed is greater than zero; Terminating.

Hereinafter, a fork control method of an automated warehouse crane according to a preferred embodiment of the present invention with reference to the accompanying drawings will be described in detail.

2 is a graph showing the speed change of the fork over time to obtain the optimum control path of the fork. 3 shows a system for obtaining a control path as in the graph of FIG.

The system includes a main board 40, an input / output board 50, an inverter 60, a driver 70, and a fork position / limit detector 80.

The main board 40 includes a central processing unit 41, a storage unit 42 and a fixed cycle timer 43 and manages the control system as a whole. The input / output board 50 is connected to the main board 40 so that signal exchange is possible, the inverter control unit 51 controlling the inverter 60, the fork position and the fork movement detected by the detection unit 80. It includes an input and output control unit 55 for receiving a limit and transmitting a control signal of the main board 40. The input / output board 50 is connected to the inverter 60 and the detection unit 80. The inverter 60 controls the driver 70 from a signal transmitted from the main board 40. The driving unit 70 is composed of a motor unit which is a power source and a device connected to the fork to control the moving speed and the length of the fork.

Looking at the drive of the system made in this way as follows. 4 is a sensor attachment diagram showing a fork mechanism diagram and a state in which the sensors are attached. If the signals detected by the left and right position discriminating sensors 91 and 92 of the fork and the left sensor 93 and the right sensor 94 which detect the left and right limits of the fork are both off, the fork center If the left sensor and the limit sensor are on, the left limit is displayed. If the right sensor and the limit sensor are on, the right limit is displayed.

5 is a flowchart for obtaining an optimum position control path of the fork, and the flow starts 110 according to the signal 100 provided from the periodic timer of the main board.

The first step 120 determines whether the flag is on. If the flag is on, the second step 130 proceeds, otherwise it ends.

In the second step 130, the reference position value set by the timer signal preceding the reference position value and the target speed movement amount are added together. If the signal applied from the timer is the first signal, since the initial reference position value is zero, the target speed movement amount may be input to the new reference position value.

The third step 140 compares the reference position value input in the second step 130 with a value corresponding to the target position.

In the fourth step 150, when the reference position is larger than the target position, the reference position is changed to set the target position as the new reference position. Of course, if the reference position is not larger than the target position in the third step 140, the next step proceeds.

The fifth step 160 obtains a value of FIFO (first in first out) corresponding to the reference position set in the fourth step 150. This FIFO is a program memory structure that refers to a structure in which a value entered first is lost first. The value changes according to acceleration / deceleration speed.

In a sixth step 170, the value of the FIFO is summed and divided by the number of signals input by the fixed period timer. That is, the average of the FIFO value is obtained and the value is set as the speed reference position.

The seventh step 180 sets a value obtained by subtracting the previous speed reference position from the value of the speed reference position as the moving speed of the fork.

The eighth step 190 newly sets the value of the previous speed reference position to the value of the speed reference position obtained in the sixth step 170 in order to obtain another new speed to the signal newly applied by the fixed period timer.

The ninth step 200 outputs the speed obtained in the seventh step 180 through the inverter.

The tenth step 210 determines whether the speed obtained in the seventh step 180 is greater than zero. If the speed is greater than zero, the process ends in the flag-on state in which the value set through the ninth step 200 in the second step 130 remains as it is.

If the determined value is zero, the process is terminated after performing the eleventh step 220, which is to erase all set values, that is, turn off the flag.

One data table of program simulation through the execution of the flowchart is shown in FIG.

The values of the FIFO, the sum of them, the speed reference position, and the speed are shown according to the time sampled by the periodic timer. When the flow chart of FIG. 5 is started with the flag turned on as described above, if it is repeated 21 times according to the sampled time, the speed indicating the difference between the speed reference position and the previous speed reference position becomes zero and the flag turns off.

According to such a control flow, the optimum control path to the target position of the fork as described later is calculated. That is, the process for obtaining the optimum control path to the target position of the fork will be described with reference to FIG.

First move the fork to the center (target position = 0). Then, the fork is moved to the left limit, and the reference position value until then is stored (target position = maximum value). Here, the movement to the left limit is sensed by the left sensor (93 in FIG. 4) and detected by the limit detection plate. The fork is then moved back to the center (target position = 0). Here, the movement to the center of the fork is detected by the central detection plate. Subsequently, the fork is moved to the right limit, and the reference position value until then is stored (target position = maximum value). Next, the average of the previously stored reference position values is obtained. It becomes the value of the objective length of the fork of this average value.

Then, it is determined whether the low-speed moving distance is defined, and if defined, it is subtracted from the average value. The measured value represents the distance moved at low speed, which is the same as the distance moved at high speed in the fork movement control.

Therefore, the fork control method of the automated warehouse crane according to the present invention configured as described above is a step of automatically generating an optimal path to the position, given a target position value and speed, and fork using these steps. It is very useful to automatically obtain the optimum control path of the fork even when the external conditions are changed through the steps of automatically measuring the length of.

Claims (3)

Inputting a periodic signal necessary for sampling through the fixed period timer, setting a reference position according to the target speed movement amount, setting a speed reference position, and the difference between the speed reference position and the previous speed reference position. Setting the speed of the fork, outputting the set speed through the inverter, determining whether the speed is greater than zero, and ending the flag when the speed is less than zero. How to control the fork. The method of claim 1, wherein the setting of the speed reference position comprises: setting a reference position with respect to a target position; Obtaining an average for each FIFO value corresponding to the set reference position: Fork control method of the automated warehouse crane comprising a. The method of claim 2, wherein the target position comprises: moving the fork to the center; Storing the reference position value until then after moving the fork to the left limit; Moving the fork back to the center; Storing the reference position value until then after moving the fork to the right limit; Computing the average of the stored reference position value; Fork control method of the automated warehouse crane comprising a.