JPS6160001B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a stacker crane that operates under automatic control, and particularly to a control device for a stacker crane. Conventionally, in order to stop a Statzker crane at a target position, a detector would issue a stop signal by blocking the striker set at the destination address (stop position), and the Statzker crane would stop. In the case of a failure to stop at a fixed position, such as when the position is slightly too far from the target position or because the vehicle is not traveling enough, it is lacking in the ability to easily and immediately stop the vehicle at the fixed position by restarting the vehicle. The operating rate was not very high due to problems such as brake wear and misalignment of the striker, which caused the machine to stop at a fixed position. In addition, conventionally, the traveling drive of a Statzker crane simply receives a traveling command from a computer and uses that command as a driving condition, and the direction of the traveling command from the computer and the actual traveling direction of the Statzker crane are monitored. As a result, if the stacker crane moved in the opposite direction of the computer's travel command, it could not be checked for any abnormalities, posing a safety problem. Also, when driving at low speed, the target position (stop position)
If the striker that is supposed to be set is missing, or if the stop function is disabled and the engine does not stop even after a stop command has been issued, the engine may continue to operate at low speeds and burn out the motor. This was not desirable from a safety standpoint. In addition, in the fork operation performed after the travel operation of the Statzker crane to the target position is completed,
As a starting condition for the fork, the detector inputs that detect the front and rear of the address detection striker were taken in, but the stacker crane does not always stop at the fixed position of the target position, and the address detecting striker does not always stop at the fixed position of the target position. In some cases, the detection striker may be stopped at the very edge of the front or rear end, and in such cases, the vibration of the stacker crane caused by the backlash of the traveling gear or the activation of the fork may cause the stacker crane to shift and cause the rear or front detection to occur. The fork may not start even though the device input is OFF and the deviation is large enough to perform fork operation, or the fork that is starting may stop, requiring effort to restore, which is unfavorable in terms of improving operating efficiency and safety. Ta. The present invention aims to improve the safety of systems equipped with stacker cranes. An embodiment of the present invention will be described below with reference to FIGS. 1 to 13. FIG. 1 is a schematic diagram of a stacker crane and a striker arrangement diagram in an automated warehouse system. In this system, the stacker crane 1 stores work data in the computer according to the operator's work instructions, travels to a specified address based on the work data, and transfers the load on the fork 2 of the stacker crane to the rack 7. It is for storing. A control device that performs the control is housed in the onboard control panel 5.
In addition, the recognition of travel addresses in the travel control of the Statzker crane is carried out by means of strikers 6 installed at equal intervals on the travel path for each address corresponding to each rack, and a detector 4 installed at the bottom of the Statzker crane that blocks light and allows light to pass through. The computer receives the ON-OFF signal generated by this process and performs address calculations. FIG. 2 shows the arrangement positions of the detector 4 and striker 6 shown in FIG. 1. The detector 4 is a U-shaped photoelectric detector that straddles the striker 6, and when the striker 6 blocks light, the contact output turns ON. (Hereinafter, the state when light is blocked is referred to as the ON state.) The detector 4 includes each of the detectors 8 and 8 described below.
Consists of 9, 10, 13, and 14 as a set. In this set, the address set detector 13 is for detecting a running address, the address reset detector 14 is also for detecting a running address, and the address set detector 13 is for detecting a running address.
It is used together with the address recognition by the logic of ON-OFF signals of both. The address recognition cycle is shown in the table below. In other words, regardless of whether Statz Car Crane 1 moves forward or backward, the ON status at STEP 4 shown in the table below while driving is
- When the OFF signal pattern is recognized, the traveling address is increased by 1 when moving forward, and decreased by 1 when moving backward.

[Table] Address count cycle Now, the front and rear detectors 8 and 9 are detectors that detect that the vehicle is stopped at the fixed position of the destination address.
When both detectors are ON, it can be recognized that the robot is stopped at the fixed position of the destination address. Also, one side
When it is OFF, for example, when the front detector 8 is OFF and the rear detector is ON, it can be detected that the stacker crane has stopped before the destination address. It can be seen that in the reverse ON and OFF states, it is from the rear. In addition, the center detector 10 detects that the stacker crane has stopped within the tolerance of the fixed position of the destination address, and the vibration of the stacker crane after stopping at the fixed position of the destination address may
If the front or rear detector is off the striker,
Operating equipment that is turned OFF and captures these signals as activation conditions (actually fork operation)
The detection result of the center detector 10 is taken in to prevent the center detector from being stopped unnecessarily. FIG. 3 is a detailed view of the mounting dimensions and position of the detector 4. It is assumed that the detector 4 is stopped at a fixed position at address n. Address reset detector 1
4 is located between addresses n and (n+1). Also, the striker 6 is connected to each striker 11, 1.
The address set detector 13 is located at the center of the count detection striker 11, and the center detector 10 is located at the center of the center detection striker 12.
The mounting position of the front and rear detectors 8 and 9 is the striker 11.
It should be l ₂ from the end. As shown in FIG. 3, the lengths of each striker are 2l ₃ and 2l ₁ . Now, in l ₂ and l ₁
By selecting the length of the center detection striker 12 so that l ₁ > l ₂ , it is possible to avoid unnecessary stops such as fork movement caused by vibrations of the stacker crane. The mechanism is shown in FIG. However, l ₁ and l ₂ change depending on the accuracy required for the system, but l ₁ > l ₂ is always satisfied. FIG. 4 shows a flowchart of input and output signals. The computer 15 includes a central processing unit, an arithmetic unit, a storage unit,
The computer 15 is a central part that controls the system and is composed of an input/output section, and a control program is stored in the computer 15. The input signal relay 16 connects various external detectors 8, 9, 10, 1
The ON-OFF signals of 3 and 14 are replaced with relay contact signals, and the computer 15 can take in this relay contact signal as input information to recognize the external situation. In addition, the output signal relay 22 replaces the command output from the computer 15 with a relay contact signal, and the motor control circuit 23 receives the relay contact signal and is configured with a relay sequence to control the running of the stacker crane 1. By issuing a running command for the stacker crane 1 to the motor 3, the running of the stacker crane is controlled. FIG. 5 shows an example of a program for bucking control and low speed output time limit check. First, the traveling direction, speed pattern, and relative traveling address number are recognized from the work setting data, and then the stack car crane 1 starts traveling and automatically accelerates and decelerates according to the programmed speed pattern. . The flowchart shown in Figure 5 is as follows:
This is from low speed output after deceleration to high speed, medium speed, and then to stop. Note that the speed pattern and running acceleration/deceleration programs are the same as those of the prior art and are omitted because they are irrelevant to the present invention. Now, if the address count cycle is not recognized according to the pattern shown in the previous table after the low-speed output is output, a time over check is performed by the program processing in program block 2, and runaway running can be prevented. Note that this low speed time limit is the time required to travel to the second address at low speed, but this time may be any time required by the system. Next, the backing process will be explained. When the vehicle reaches the destination address while traveling at low speed (block 3), it is first determined whether or not backing is being executed using a determination bit (hereinafter referred to as a management flag) provided in a storage section inside the computer 15. When traveling at low speed and arriving at the destination address, since backing is not being performed, block 5 is performed to stop the stacker crane 1. Immediately after the stop command is issued, the stacker crane 1 is decelerated by the brake and the gears are bumped when stopping, so in order to avoid these times, the delay time T ₁ is set.
(Block 6). This day time
At _T1 , the computer program counts from after the low speed command and determines on the program that the time has expired. At that timing, it is determined whether the stacker crane is stopped at the fixed position of the target address by inputting the detector information. The shaded area shown in FIG. 6 is for each detector 8, 9.
Since both are in the ON state, this is an area that the computer 15 determines to be the normal position. If the vehicle is in the normal position, the travel control is terminated, but if the vehicle is not in the normal position, it is determined whether or not bucking is possible. (Block 8) In FIG. 6, F indicates the forward limit and R indicates the backward limit. The forward limit of the bucking possible condition is the detector position shown in FIG. 8, and the backward limit is the detector position shown in FIG. Therefore, if the stacker crane 1 is in the range between the fixed position stop position (the relative position in FIG. 7) and the extreme position of the bucking possible condition, the bucking operation will be performed. Therefore, as shown in Fig. 7, when the detectors 8 and 13 are ON, the bucking command is performed at a low forward speed (block 16), and as shown in Fig. 8, when the detectors 13 and 9 are ON, the bucking Reverse slow speed (block 1)
0), issues a bucking command to the stacker crane, and sets a management flag indicating that bucking is in progress (block 11). Note that the output time _T2 of the bucking command varies depending on the low speed of the vehicle and is not unambiguous, but in this embodiment, it is set to 1 second. When the computer 15 determines that the delay time _T2 has timed up as described above, it turns off the speed command. (Block 13) The subsequent program block 14 also has a delay time _T3 . The reason for this is to capture detector information in a completely stopped state. Next, when the delay time _T3 has elapsed, the computer 15 reads the detector information and determines whether it is in the area shown in FIG. (Block 15) This judgment is made when the detectors 8, 9, 10, and 11 are turned ON simultaneously. If the stacker crane 1 is stopped at the normal position, the travel control is terminated, but if it is not at the normal position, it is determined that the fixed position is abnormal and the stacker crane 1 is stopped. In this flow, the case where the backing process is performed once is described, but if the backing process is performed two or more times, it is sufficient to count the number of times the backing process is executed. The basic processing at that time is the same as above. As mentioned above, if the vehicle does not stop at a fixed position after it has stopped traveling to the destination address, it is easy to recognize the deviation and direction between the stopped position and the fixed position stop position, perform backing processing, and then decide whether to continue the process or not. , it is possible to determine whether the process is stopped or not, and by performing backing processing, it is possible to improve the accuracy of stopping at a fixed position. FIG. 9 shows a control circuit that compares and checks the travel command direction from the computer 15 and the actual travel direction of the stacker crane at the start of travel.
First, to explain the symbols and characters, TLR and TCF are relay contacts for backward and forward commands output from the computer 15. PHO3, PHO4
are detection input relay contacts of the front and rear detectors 8 and 9. TL is a travel drive confirmation relay. T ₁
After the relay coil TL is turned on, the relay contact is
It is a timer that turns on. AS is a relay for confirming the running direction. First, we will explain what happens when a forward command is issued while the Statzker crane is stopped at a fixed position. (The principle of retreat is the same, so the explanation is omitted.) When the computer 15 issues a forward command, the contact TLF turns on, so PHO3 and PHO4 turn on.
Because it is ON (when stopped at a fixed position, PHO
3. PHO4 is ON) At the same time as the relay coil TL is ON, the timer _T1 relay coil is also ON. The time Ts set when the relay coil of the timer _T1 is turned on is longer than the time from when a running command is given to one of PHO ₃ and PHO ₅ turning OFF, and when both PHO ₃ and PHO ₅ turn OFF. OFF
Set it smaller than the time. Figure 10 shows a time chart of PHO ₃ and PHO ₅ in the case of a forward command. Here, the time of timed timer _T1
Ts is (t ₂ −t ₁ )<Ts<(t ₃ −t ₂ ). When the forward command TLF is output and time Ts has elapsed, contact _T1 turns ON. At this time, contact TL is ON. Therefore, if the command TLF is turned on,
However, if PHO3 is ON despite the fact that
is turned ON, the relay coil TL is turned OFF, and the contact TL shown in Fig. 1 is turned OFF, so the motor 3 stops and an emergency stop occurs. Therefore, by checking the travel command direction from the computer 15 and the stacker crane travel direction, if the two do not match, it is possible to know that there is an abnormality in the signal transmission system, etc., and the danger of traveling in the opposite direction can be prevented. , safety can be increased. In summary, in the circuit shown in FIG. 9, after the travel command is output, the timer starts counting, and after a predetermined period of time has elapsed, the detector 8 detects the address detection striker 11 under the condition of the forward command TLF ( PHO ₃
ON), or when the rear detector 9 detects the address detection striker 11 under the conditions of the rear command TLR (PHO ₅ is ON), it is determined that the vehicle is traveling in the opposite direction and a signal is output to stop traveling. It is a circuit. FIG. 11 shows the traveling motor drive circuit. Among these, the direction/speed control circuit for driving the motor is blackboxed because it differs depending on the type of motor 3 used and the control method. In other words, if the relay contact TL is ON, the travel motor can be controlled by turning the control circuit ON and OFF using the logic set according to the travel control sequence. FIG. 12 is a schematic diagram of a fork activation control circuit. HL indicates that TL1 is running.
1 is a relay indicating that the elevator is being driven up and down.
Further, a contact point A is a contact point that indicates ON/OFF of the center detector 10. FO is a relay that indicates that Fork 2 is activated. Now, by incorporating the a contact point of PH5 of the center detector 10 as a starting condition for the fork 2, after the stacker crane 1 stops at a fixed position and shifts to fork operation, the front Alternatively, even if the rear detector 8 (or 9) is deviated from the striker 11, as long as the deviation shown in FIG. 13 is within (l ₁ -l ₂ ), the fork operation can be performed normally. This (l ₁ - _{l 2} ) deviation tolerance is determined by system requirements and is not unambiguous, but by providing a striker that provides this tolerance, unnecessary stops can be avoided. can be avoided and system availability can be increased. In Figure 13, the fixed position stop range and center detector 1
This figure compares the stop position ranges resulting from the provision of 0 and shows the permissible ranges thereof. The allowable ranges for the A direction and the direction opposite to the A direction are shown in the shaded areas. In FIG. 13, the solid line ◯ indicates the extreme position within the allowable range, and the dotted line ◯ indicates the extreme position within the normal position range. As described above, according to the present invention, when a travel command is given, a check is made between the travel command direction and the actual travel direction, so it is possible to prevent the vehicle from traveling in the direction of an obstacle. This can prevent accidents such as unloading goods from shelves at other addresses and improve safety.

[Brief explanation of the drawing]

Fig. 1 is an elevational view showing the outline of a stacker crane and the arrangement of a detector and a striker, Fig. 2 is a perspective view showing detailed arrangement positions of a detector and a striker in an embodiment of the present invention, and Fig. 3 is a Figure 2 is a plan layout showing the arrangement of the detector and the dimensions of the striker, Figure 4 is a flowchart of input/output signals in the embodiment of the present invention, and Figure 5 is the bucking and low speed output time limit in the embodiment of the present invention. Check program diagram, Figure 6 is a fixed position stop recognition area display diagram in an embodiment of the present invention, Figure 7 is a backward bucking limit position display diagram in an embodiment of the present invention, and Figure 8 is an embodiment of the present invention. FIG. 9 is a travel start direction check circuit diagram in an embodiment of the present invention, FIG. 10 is a travel start direction monitoring time chart in an embodiment of the present invention, and FIG. FIG. 12 is a schematic diagram of a fork starting control circuit in an embodiment of the invention, and FIG. 13 is a diagram showing a stop position tolerance range in an embodiment of the invention. 1... Stutzker crane, 2... Folk,
3... Drive motor, 8... Front detector, 9...
Rear detector, 10... Center detector, 11... Address detection striker, 12... Center detection striker, 1
3... Address set detector, 14... Address reset detector, 15... Computer.

Claims (1)

[Scope of Claims] 1. A control device for a stacker crane, comprising a computer that detects an address detection striker installed at each address with a detector, calculates a detection signal from the detector, and causes the crane to travel toward a destination address. , which detects a single address detection striker while stopped at the destination address, and is equipped with a front detector and a rear detector arranged at intervals in the running direction of the stacker crane, and is equipped with a front detector and a rear detector arranged at intervals in the traveling direction of the stacker crane, and whether the crane is moving forward or backward. A timer is provided to start counting a predetermined time after the command is given, and the predetermined time is longer than the time when one of the front detector and the rear detector stops detecting the address detection striker after the travel command is given. , set to be shorter than the time during which both of them stop detecting the address detection striker, and after the predetermined time has elapsed, if the front detector detects the address detection striker under the condition of a forward command, and under the condition of a reverse command. A control device for a stacker crane, comprising a circuit that outputs a signal to stop traveling when the rear detector detects an address detection striker.