JPS6169602A - Method of controlling stacker crane - Google Patents

Abstract

PURPOSE:To prevent easily a stacker crane from large sway by obtaining a sway amount of the stacker crane in travel and stoppage to control an elevational speed control unit of the stacker crane for minimizing the sway amount. CONSTITUTION:In a stacker crane 1 movable along upper and lower rails disposed along racks of an automatic warehouse are provided travel detecting units 118, 119 for detecting travelling speed on respective travelling units 106, 105 for rotatably driving wheels travelling on the upper and lower rails. And according to the vertical travelling amounts x1, x2 of stacker crane detected by the respective detecting units 118, 119 is calculated the vertical travelling deviation amount by a calculating unit 2 to generate the speed control signal outputs V1, V2 to obviate this deviation. Next, after these signals V1, V2 are V/F converted 30, 40, they are contrasted with the outputs of the respective travel detecting units 118, 119 to obtain a correction amount based on the deviation between both signals and outputs for speed control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a control method for a stacker crane, and particularly to a control method for reducing shaking when a stacker crane stops traveling.

[Background of the invention]

Star car cranes are often used as cargo handling machines in automated warehouses. A normal stub car crane is a crane that loads a load onto an elevating body, travels along the upper and lower rails using a traveling device, and transports the load to a target shelf by raising and lowering the elevating body using a lifting device. be. The traveling device of a stacker crane consists of wheels that run on rails, a drive motor that provides rotational driving force to the wheels, and a power adjustment section that adjusts the power supplied to the motors.
For example, it consists of a thyristor power converter). In order to support the stacker crane, a rail is also provided at the top, and guide rollers are attached so that it can run along the rail.

Well-known anti-sway equipment for preventing the stacker crane from shaking when it travels to the target position uses electromagnets and friction members to stop the shaking by braking. be. This is disclosed, for example, in Japanese Utility Model Publication No. 49-10624.

Such a known shaking prevention mechanism of a stacker crane is useful for preventing shaking when the crane is stopped, thereby increasing the efficiency of the stacker crane. Incidentally, recently, there has been a trend toward the construction of higher-rise warehouse shelves with the aim of increasing the storage density of automated warehouses. Along with this, the height of stacker cranes used to handle cargo on warehouse shelves has become higher, and they have also started to run at higher speeds to improve cargo handling efficiency.

Under such circumstances, if only the conventional shaking prevention mechanism is used, the function of preventing the stacker crane from shaking when the crane is stopped is insufficient, and a problem arises in that it takes time for the shaking to become smaller.

In order to reliably prevent shaking of a large stacker crane that travels at high speed, a large-scale anti-sway mechanism is required to prevent the shaking, resulting in an increase in the weight of the stacker crane and a significant increase in price.

[Purpose of the invention]

An object of the present invention is to provide a method for controlling a stacker crane that can reduce the shaking of a stuffer crane to a small extent with a simple configuration.

[Summary of the invention]

In order to prevent the stacker crane from shaking caused by traveling and stopping operations, the present invention provides separate traveling devices for the upper and lower parts of the stacker crane so that the upper and lower parts of the stacker crane can be controlled separately. At the same time, the vertical running deviation amount of the stacker crane is detected, and this running deviation amount is used to calculate the vertical speed control signal to eliminate the deviation, and based on this speed control signal, the above-mentioned upper and lower It is characterized by controlling the speed of each traveling device.

[Embodiments of the invention]

Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 is a control block diagram showing one embodiment of the present invention. FIG. 2 is a diagram showing the running status of the stacker crane, FIG. 3 is a diagram showing the configuration of the stacker crane, and FIG. 4 is an enlarged view of a part of the man's figure 3. FIG. 5 is a diagram showing the speed pattern of the stacker crane, and FIG. 6 is a diagram showing the control operation flow of the embodiment shown in FIG. 1.

First, the overall structure of the stuff car crane 1 used in the embodiment shown in FIG. 1 will be explained using FIG. ff13 and FIG. 4. In Figure 3 and Figure 4 1, 200
are warehouse shelves, 300 is the upper rail, and 400 is the lower rail. The stacker crane 1 has upper and lower rails 3
It is located between 00 and 400 and moves along this rail. Wheels 101 and 102 run on the lower rail 400, and wheels 103 and 104 run on the upper rail 300. Reference numeral 105 denotes a traveling device provided at the bottom, which drives the wheels 101 to rotate. 106 is a traveling device provided at the top, which drives the wheels 103 to rotate. 107 and 108 are guide members for preventing the stacker crane from falling; 109 is a lower truck member; 11
0 is an upper truck member, and 111 and 112 are columns connected between the truck members. 114 is an elevating body that lifts and lowers the load 113, and +15 is a fork device provided on the elevating body. 116 is a rope for lifting, 117 is rope 1
A lifting device 118 and 119 detect the running speeds of the lower and upper portions, respectively, and 120 detects the lifting position of the lifting body 114. This is a lift detection device. iJ! In FIG. 4, 121 is a support plate, 122 is a support member, and 123 is a mounting member connected to the support plate 121 with a pin. The traveling device 106 is attached to this attachment member 123. 124 is a drive motor, 125 is a gear on the motor side, and 126 is a gear on the wheel 103 side.

Next, the embodiment shown in FIG. 1 will be described. In FIG. 1, 1 is the stacker crane shown in FIGS. 3 and 4. 2 is an arithmetic unit, specifically a microcomputer may be used.

I and Sum are V/F circuits that convert voltage signals into corresponding frequency signals, 31 and 41 are adders, 32 and 42
is a proportional control circuit, the rest is a limiter, and the rest is an adder. Reference numeral 5 represents an inverter circuit, which transmits power at a frequency corresponding to an input signal to respective traveling positions 105 and 1.
06 to perform speed control.

6 and 7 indicate integrators. The arithmetic device 2 has a speed setting voltage V
, , V2 is output as a command signal. The V/F circuit 40 generates frequency signals f, , f based on the signal.

Output. The inverter circuit 5, which receives this signal via the adder 44, generates electric power according to the frequency and supplies this to the upper and lower traveling devices 105 and 106, thereby causing the stacker crane I to travel. . The outputs of the V/F circuits are also output to adders 31 and 41, respectively, and the deviation from the output (speed) of the travel detection devices 119 and 118 is determined, and is outputted via the proportional control circuit blade 42 and the limiter blade 43. The correction amount of the frequency signal is added by an adding device, 44
are given to each.

In this way, speed control is implemented. In addition, i*i
The device 2 inputs the upper and lower travel distances, which are the outputs of the integrators 6 and 7, and uses these travel amounts to control the stacker crane to prevent it from shaking. This will be explained in detail below.

The stacker crane 1 shakes as shown in FIG. 2 while traveling or when stopped.

In Fig. 2, xl+''! indicates the traveling distance without shaking. x, / indicates the traveling distance of the upper part when there is shaking as shown by the dotted line in the figure. The swing width δ of 1 is expressed by the following equation.

δ=x, -X2...
(1) However, x: travel amount x on the lower side, travel amount on the double side, and the swing speed δ are expressed by the following formula.

However, Ml: Lower traveling speed Ml: Upper traveling speed When the position to which the stacker crane 1 should move is set, the calculation device ii2 calculates the position it should move from the current position.
By determining the distance (target mileage) xr at
105 travel speed patterns are determined. This pattern is, for example, as shown in FIG. The constant speed running period t4 of the stacker crane in this pattern is obtained by the following equation.

t4=(xr-(”-=1°(tl+t7)+XI.(
tz+tg)+xu(ts+ts))/xo
・−−・−・(31 Moxibustion, .: Intermediate speed t, 11 Time from start of movement to reaching intermediate speed t7: Time from intermediate speed to stop'!+t6: Intermediate speed is maintained β, moxibustion, I
: Steady traveling speed t, : Time required for acceleration from intermediate speed to steady traveling speed t5: Time required to decelerate from steady traveling speed to intermediate speed Now, the traveling speed pattern of the upper traveling device 106 of the stacker crane 1 is also as follows. It is almost the same as Figure 5, but
In the embodiment of the present invention, in order to reduce the vertical swing width δ, the speed is controlled to be as follows.

◇　　.

X2=X2+k(XI-Xi) ・−・−・−・
・−・−(4 squares, M2: Target speed setting value at this time of sampling ÷ -° plane H square・nopri・y/7゛ plane Niwan Tomari eaves fixed value: Position speed gain XI: Lower side travel Quantity

-X, ) to calculate a speed control signal that eliminates this deviation, and input it to the V/F circuit.

This reduces the amount of vertical travel deviation and reduces the shaking of the stacker crane.

Next, a flowchart 1 showing the operation of FIG. 1 described above is shown in FIG. 6.
I will explain using The flow on the left side of Figure 6 (step ■ ~
(2) shows the entire operation from the start of running to the time of stopping. The flow on the right side of the gSG diagram (steps ① to 0) shows the speed control operation to prevent shaking. When the position to which the stacker crane is to be moved is set while the stacker crane is in a stopped state, steps ① to ① are executed in sequence.

Step 2... Initial settings of the arithmetic device 2 are performed.

Step ■・・・Determine the target mileage X, and set the speed pattern using the second X. Also, (3)
The constant speed running time t4 is calculated using the formula.

Step ■・・・Current mileage X and x
Clear 2 to zero.

Step (2)...Starts running and drives the lower traveling device 105 according to the speed pattern described above.

The upper traveling device 106 is also driven in the same manner. If a deviation (XI-Xz) occurs in the vertical travel distance, speed control is performed to prevent shaking so as to eliminate the deviation (XI-Xz).

The operation of step (2) is shown in steps (2) to (2), which will be described later.

Step, B ■... Step ■ is repeated until the vehicle travels near the destination. That is, I Xr-Xl
Repeat step ■ until l becomes ε1 or less, and ε
When it becomes 1 or less, proceed to the next step.

Steps ■, ■... When the lower position of the stacker crane reaches the target stop position, the brake is applied and the traveling device 106 is controlled so that the upper position reaches that position. , the brake is applied while performing anti-sway control.

Next, the details of the operation of step ■ above are explained in steps ■~0.
This is explained by:

Step 2: Speed control of the lower traveling device j 105 according to the speed pattern is performed at regular intervals.

Step (2): Detecting the distance of elevation as the elevating body 114 moves.

Step 0...Detect travel amount X,,X@.

Step ■・・・X detected in step ◎,,X
Using fi, find the running deviation amount δ("XI

Step ■...The current deflection angle a of the elevating body 114 is determined from the running state quantity obtained from steps ■ and ◎.

Step [F], ◎... Replace the current running condition with the five-stage mode shown in the following table, and select the upper running table 2. Step O... Gain obtained in step O. Using k, the upper traveling device t 10 is calculated based on the above equation (4).
6 is determined, and the traveling distance M 106 is controlled based on this.

According to this embodiment, the amount of sway δ when the stacker crane is running and when it is stopped is determined, and the upper and lower speed control bags 5t 105 are adjusted to minimize this amount of sway.
, 106 speed control, and can significantly prevent shaking without the need for a special anti-sway mechanism.In addition, by using it in conjunction with a conventional anti-sway mechanism, the anti-sway function can be further improved. do.

〔Effect of the invention〕

As explained above, according to the present invention, the shaking of the stacker crane can be reduced with a simple configuration.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing the running status of the stacker crane, Fig. 3 is a diagram showing the configuration of the stacker crane, and Fig. 4 is a part of Fig. 3. The enlarged diagram, the lower figure 5, is a diagram showing the speed pattern of the stacker crane, and FIG. 6 is a diagram showing the operation flow in FIG. 1. l...Stacker crane, 2...Arithmetic unit, 30, 40...171 circuit, 31.4
1...Adder, n. C...proportional control circuit, 0...limiter, ah. Signal: Adder, 5: Inverter circuit, 6, 7: Integrator, 105, 106...
- Traveling device, 118, 119... Traveling detector. Fa, drawing figure 6

Claims (1)

[Claims] 1. In a method for controlling a stacker crane, in which a load is loaded on an elevating body, the hoist is moved along upper and lower rails by a traveling device, and the load is transported to a target shelf by raising and lowering the elevating body using a lifting device. , which detects the vertical running deviation amount of the stacker crane, uses the running deviation amount to calculate a vertical speed control signal to eliminate the deviation, and is installed separately at the upper and lower parts of the stacker crane. A method for controlling a stacker crane, characterized in that a traveling device performs speed control based on the corresponding speed control signal.