JPH037563B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for controlling the elevation of a lifting carriage in a loading/unloading crane that travels along a three-dimensional shelf. (Prior Art and Problems) As a method for controlling the elevation of the elevating carriage in the loading/unloading crane as described above, a moving distance measuring means is used to replace the moving distance of the elevating carriage from the origin with a pulse count value, learning movement of the elevating carriage and storing a pulse count value when the elevating carriage reaches a preset stop height as a learned absolute address for each stop height;
During actual operation, a control method has been devised in which the lifting carriage is controlled to rise and fall based on the difference between the learned absolute address corresponding to the target stopping height and the pulse count value of the moving distance measuring means. In such a control method, there is a difference between the lifting distance corresponding to the pulse count value of the moving distance measuring means and the actual lifting distance of the lifting carriage due to elongation of the drive chain that drives the lifting carriage up and down or other causes. If this occurs, even if the stop control itself is performed normally, the actual stopping height of the elevating carriage will deviate from the target stopping height, making it difficult to carry out safe loading and unloading operations to the cargo storage section of the three-dimensional shelf. I can't do that. In order to solve such problems, for example, by applying the technical idea disclosed in Japanese Patent Application Laid-Open No. 56-82708, the stopping position when the elevating carriage returns to the home position (generally the lowering limit position) It is conceivable to detect the error and correct the learning absolute address corresponding to the target stop position according to this error, but this method does not eliminate the negative effect of the stop position error at the home position of the elevating carriage. However, this method eliminates the error in the carriage stop position caused by an error between the distance corresponding to the pulse count value and the actual carriage lifting distance due to the elongation of the lifting drive chain of the lifting carriage. That is not possible. Furthermore, by applying the technical concept disclosed in Japanese Patent Application Laid-Open No. 140471/1985, a pulse count value is set for each level of the lifting carriage each time it passes through the stop position of each level. It is conceivable to replace it with a learned absolute address. According to this method, it is possible to reduce the carriage stop position error caused by the elongation of the carriage lift drive chain as described above, but when passing the stop position one position before the target stop position, the pulse meter Since the numerical value is replaced with the learned absolute address, the lifting distance from the previous stop position to the target stop position is large, and the error that occurs during this time, that is, the lifting distance corresponding to the pulse count value and the actual lifting distance. The error between the positions is also large, making it impossible to sufficiently improve the stopping position accuracy at each stopping position of the elevating carriage. (Means for Solving the Problems) The present invention aims to solve the problems in the above-mentioned control method, and its feature is that the position of the elevating carriage with respect to the origin is determined by a pulse meter. Provide a means to measure the lifting distance by replacing it with numerical values,
On the side of the elevating path of the elevating carriage, there is a lower detection plate whose center height of the vertical width corresponds to the stop height when leaving the warehouse, and a lower detection plate whose center height corresponds to the stop height when entering the warehouse, at a position corresponding to each stack storage section of the shelf. A corresponding lower plate to be detected is installed in parallel, and a detector for detecting the plate to be detected is provided on the elevating carriage side, and the elevating carriage is moved up and down by learning, so that the detector detects the upper and lower edges of each plate to be detected. The pulse count value in the moving distance measuring means when detecting the edge is stored in advance as a learned absolute address, and during actual operation, the pulse count value in the moving distance measuring means when the detector detects the edge of the detected plate is stored in advance. The pulse count value at the target stop height is replaced with the learned absolute address, and the stop value is calculated and stored in advance for each stop height, or is calculated each time based on a set of learned absolute addresses above and below the target stop height. The object of the present invention is to perform stop control of the moving body based on the difference between a target value and a pulse count value in the moving distance measuring means. (Function) According to the above control method, as the carriage moves up and down, the pulse count value of the moving distance measuring means automatically increments, and the detector of the carriage detects the load immediately before each stop height. Every time a detection plate edge is passed, the pulse count value of the moving distance measuring means is automatically replaced with a learned absolute address stored corresponding to the detected plate edge. When the elevating carriage reaches the target stop height, the detected edge immediately before the target stop height is detected and the address is replaced with a learned absolute address, and then the pulse that is incremented as the carriage moves up and down is replaced with a learned absolute address. Carriage stop control is performed based on the difference between the count value and a stop target value corresponding to the target stop height. Therefore, even if there is an error between the lifting distance of the lifting carriage and the pulse count value,
When the lifting carriage passes through each stop height, there is an error between the pulse count value during learning (learning absolute address) corresponding to the actual height of the lifting carriage and the actual pulse count value in the moving distance measuring means. will almost never occur. (Example) An example of the present invention will be described below based on the attached illustrative drawings. In FIG. 1, reference numeral 1 denotes a three-dimensional shelf provided with a large number of cargo storage sections 2 divided vertically and horizontally, and each cargo storage section 2 is provided with a pair of left and right cargo receivers 3. Reference numeral 4 denotes a loading/unloading crane that runs along the three-dimensional shelf 1, and includes a cargo storage section 2 of the three-dimensional shelf 1.
It also has an elevating carriage 8 equipped with a running fork 7 for transferring loads 6 to and from a loading handling platform 5. The unloading operation using the elevating carriage 8 equipped with the running fork 7 is carried out at a lower stopping height H at which the running fork 7 is slightly lower than the cargo receiver 3 in the cargo storage section 2 to be unloaded, as shown in FIG. After stopping the elevating carriage 8 at _{step 1} , advance the running fork 7 into the shelf, then raise the elevating carriage 8 to the upper stop height _H2 at which the running fork 7 is slightly higher than the cargo receiver 3, and then start running. Fork 7 is moved backwards out of the shelf. The warehousing operation is performed by a forking operation in exactly the opposite order to the forking operation during the above-mentioned warehousing operation. In FIG. 3, reference numeral 9 denotes a motor that drives the lifting carriage 8 up and down via a lifting chain 10, which is controlled by an lifting control device 12 controlled by a control computer 11, and a pulse encoder 13. Linked together. The pulses sent from the pulse encoder 13 are sent to an addition/subtraction counter 1 which performs addition and counting when the elevating carriage 8 goes up, and subtracts and counts when it goes down.
4, and the counted value is input to the control computer 11. Reference numeral 15 denotes a detection plate attached to the lifting guide column 16 of the lifting carriage 8 at a height corresponding to the load storage section 2 and load handling platform 5 of each level of the shelf 1. , as shown in Fig. 4, the center height of the vertical width D is the lower stop height H ₁ explained based on Fig. 2.
Lower detection plate portion 17 and upper stop height corresponding to
and an upper detection plate portion 18 corresponding to _H2 ,
The vertical width D of each of the detected portions 17 and 18 corresponds to the permissible range of the stop height error of the running fork 7 with respect to the above-mentioned stop heights H ₁ and H ₂ . As shown in FIG. 3, in addition to the detection plate 15, the lifting guide column 16 has an origin detection plate 19 at a height corresponding to the lowering limit height of the lifting carriage 8.
is prominent. On the other hand, as shown in FIG.
A detector 20 for detecting 8 and a detector 21 for detecting the origin detection plate 19 are attached. Detection signals from these detectors 20 and 21 are input to the computer 11. Prior to carrying out the loading/unloading work using the crane 4 for loading/unloading, the learning work shown in the flowchart of FIG. 5 is performed. That is, from a state in which the lifting carriage 8 is waiting at the lowering limit height where the detector 21 detects the origin detection plate 19, the lifting carriage 8 is first moved by the motor 9 via the lifting chain 10 in order to perform upward learning. 8, the detector 21 moves away from the upper edge 19a of the origin detection plate 19 and the detection signal falls. 17 and the upper detection plate portion 18 in this order, the pulse encoder 13 linked to the motor 9 emits pulses at time intervals proportional to the movement speed of the lifting carriage 8, and the pulses are sent to the addition/subtraction counter 1.
4 counts. Therefore, an addition command is given to the addition/subtraction counter 14 based on the fact that the elevating carriage 8 is in the upward motion, and when the detection signal of the detector 21 that detects the origin detection plate 19 falls, the addition/subtraction counter 14 is reset to zero, and when the detector 20 detects the lower edge 17a of the lower detected plate portion 17 and the lower edge 18a of the upper detected plate portion 18 of the detected plate 15 at each level, the addition/subtraction counter 14 is The count value is stored and registered in the memory of the computer 11 as a learning absolute address. When the elevating carriage 8 reaches the upper limit height,
The elevating carriage 8 is switched to a descending motion to perform descending learning. Incidentally, the plate portion 1 to be detected by the detector 20
Detection signals 7 and 18 are counted separately, and when the elevating carriage 8 reaches the upper limit height, it is checked whether the total number of detected signals matches the total number of detected plate portions 17 and 18. It is possible to control the downward learning to start only when the During descending learning, the addition/subtraction counter 1 is
4 to the subtraction operation, the detector 20 detects the upper edge 18b of the upper detected plate portion 18 of the detected plate 15 at each level and the lower detected plate portion 1 of the detected plate 15 at each level.
The count value of the addition/subtraction counter 14 when the upper edge 17a of the number 7 is detected is stored and registered in the memory of the computer 11 as a learning absolute address. When the lifting carriage 8 reaches the lowering limit height, the lowering learning is completed, but in this case as well, it is possible to check the total number of detected plate portions 17 and 18 by the detector 20, as in the upward learning. I can do it. When the above-mentioned upward learning and downward learning are completed, as shown in Figure 3 and the following table, the detected board 1 of each level is
5, the upper edge 1 of the origin detection plate 19
Learning absolute addresses (pulse count values) a ₁ , _{a 3 corresponding} to the height h 1 of the lower edge 17a of the lower detection plate portion 17 with respect to 9a, the height of the upper edge 17b of the lower detection plate portion 17 Learning absolute addresses (pulse count values) b ₁ , b ₃ corresponding to the height h ₂ , learning absolute addresses (pulse count values) a ₂ corresponding to the height h ₃ of the lower edge 18a of the upper detection plate portion 18 , a ₄ ..., and the learning absolute address (pulse count value) b ₂ , b ₄ ... corresponding to the height h ₄ of the lower edge 18b of the upper detection plate portion 18.
... is obtained as learning data. Next, use the training data above to determine the lower stop height for each level.
Stop target values (pulse count values) corresponding to H ₁ and upper stop height H ₂ are calculated. That is, the stop target value corresponding to the lower stop height H ₁ of each level is the value corresponding to the height h ₁ of the lower edge 17a of the lower detected plate portion 17 and the upper end of the lower detected plate portion 17. The height of the edge 17b is calculated as 1/2 of the sum of the value corresponding to _h2 , and the target stop value corresponding to the upper stop height _H2 of each level is determined from the lower edge 18a of the upper detection plate portion 18. and the lower edge 18 of the _upper detection plate portion 18.
Calculate 1/2 of the sum with the value corresponding to the height _h4 of b. For example, the lower stopping height H ₁ of level 1 is (a ₁ +
b ₁ )/2, and the upper stopping height H ₂ at the same level is
(a ₂ +b ₂ )/2. The data thus obtained is stored and registered in the memory of the computer 11.

[Table] After the above-mentioned learning calculation work is completed, the actual loading/unloading work is performed, and the control at that time is performed by the computer 11 as shown in the flowcharts of FIGS. 6 and 7. That is, as shown in the flowchart of FIG.
When the control computer 11 sets the work content (receiving or unloading) and work target level, the target stop value for the corresponding level is stored in the memory, that is, the lower stop height H at the time of unloading. A value corresponding to ₁ is searched, and a value corresponding to the upper stop height H ₂ B is searched at the time of warehousing.
A value corresponding to the current height of the lifting carriage 8,
That is, the current address represented by the pulse count value of the addition/subtraction counter 14 is compared with the target stop value, and which one is larger is determined. As a result, if the stop target value is larger than the current address, a command to raise the elevator carriage 8 is output, and if not, a command to lower the elevator carriage 8 is output from the computer 11 to the elevator controller 12. Ru. When a work start command is input to the lift control device 12 in such a state, the loading/unloading crane 4 moves toward the position corresponding to the cargo storage section 2 to be loaded/unloaded, and at the same time, the motor 9 starts operating. to raise or lower the elevating carriage 8. As the lifting carriage 8 moves up and down, the current height of the lifting carriage 8, that is, the current address, represented by the pulse count value of the addition/subtraction counter 14 changes. The comparison is continuously checked in the computer 11. On the other hand, as shown in the flowchart of Figure 7,
When the elevating carriage 8 moves upward, the detector 20
detects the lower edge 17a of the lower detected plate portion 17 of the detected plate 15 at each level, when detects the lower edge 18a of the upper detected plate portion 18, and when the elevating carriage 8 moves downward. , when the detector 20 detects the upper edge 18b of the upper detected plate portion 18 and the upper edge 17b of the lower detected plate portion 17 of the detected plate 15 at each level, the data is used as vertical learning data. The learned absolute address corresponding to the detected edge is searched from the learned absolute addresses registered in memory (numerical values a ₁ , a ₂ ..., b ₁ , b ₂ ... listed in the table above), and the current address at that time is searched. That is, the pulse count value of the addition/subtraction counter 14 is corrected and replaced with the learned absolute address. Specifically, a correction value corresponding to the difference between the learned absolute address and the current address is calculated, and this correction value is input to the addition/subtraction counter 14 from the computer 11 side to correct the pulse count value. At this time, if the difference between the learned absolute address and the current address exceeds a certain range, control can be performed so that appropriate abnormality countermeasures are automatically taken. When the current address of the lifting carriage 8, which is automatically corrected for each level as described above, matches the stop target value, the computer 11 outputs a stop command to the lifting control device 12, and as a result, the motor 9 stops and the brake is simultaneously applied. is applied, and the elevating drive of the elevating carriage 8 is stopped. That is, when the detector 20 reaches the position corresponding to the lower stop height H ₁ (when leaving the warehouse) or the upper stop height H ₂ (when entering the warehouse) of the detection plate 15 located at the level of the object of the loading/unloading operation. , the elevating movement of the elevating carriage 8 is stopped.
Of course, at this time, the running fork 7 on the elevating carriage 8 is located at the lower stop height H ₁ (when leaving the warehouse) or the upper stop height H ₂ (when entering the warehouse) shown in FIG. After the elevating carriage 8 has stopped, the current address represented by the pulse count value of the addition/subtraction counter 14 and the target stop value are calculated, and the difference between them is calculated, for example, as shown in FIG. When the vertical width D of the detector 20 exceeds the software tolerance range d excluding the optical axis biting margin of the detector 20, an appropriate abnormality countermeasure, such as automatic overrun correction control, can be performed. Traveling of loading/unloading crane 4 and elevating carriage 8
By raising and lowering the running fork 7, the lower stopping height in the cargo storage section 2 is at the level for loading and unloading operations.
If the vehicle is located at the upper stop height H ₁ (when leaving the warehouse) or the upper stop height H ₂ (when entering the warehouse), the forking operation consisting of the combination of the moving in and out movement of the running fork 7 and the movement up and down of the elevating carriage 8, as is well known in the art, will It is possible to carry out warehousing or unloading work for a predetermined cargo storage section 2. The lower stop height H ₁ of the lifting carriage 8 during this forking operation to the upper stop height H ₂
upward movement (when exiting) or upper stopping height H ₂ B
The same control as described above can be performed also in the lifting/lowering stop control of the downward movement (during storage) from the lower stop height H _{1 to the lower stop height H 1} . In the above embodiment, when the corrected current address matches the stop target value corresponding to the vertical stop heights H ₁ and H ₂ , the motor 9 is stopped and at the same time the brake is applied to stop the lifting carriage 8. However, this lifting stop control point is set to the target stopping height.
an edge 17a or 17b of the detected plate portion 17 located immediately in front of H ₁ or H ₂ in the direction of vertical movement;
Or the edge 18a or 1 of the detected plate portion 18
8b is the time point detected by the detector 20, or corresponds to the position in front of the target stop height _H1 or _H2 in the vertical movement direction (the position within the vertical width D of the detected plate portions 17 and 18). This can be the point in time when the preset stop control addresses match. When using the latter method, calculate the error between the actual stopping height and the target stopping height H ₁ and H ₂ separately during upward movement and downward movement during learning work, and stop according to this error. By correcting the control address, it is possible to set separate stop control addresses for upward movement and downward movement. In addition, the stop target values corresponding to the upper and lower stop heights H ₁ and H ₂ were calculated and registered in advance, but
It is also possible to perform control such that the stop target value is calculated from learned absolute addresses above and below the target stop height when setting the level for the loading/unloading work. (Effects of the Invention) As described above, according to the control method of the present invention, for example, due to elongation or load of the lifting chain 10 in the embodiment, there may be a difference between the lifting distance of the lifting carriage and the pulse count value. Even in situations where an error occurs, each time the elevating carriage passes a height corresponding to the detected plate edge immediately before each stop height, the movement distance measuring means (in the embodiment, driven by the motor 9) Since the pulse count value of the pulse encoder 13 and the addition/subtraction counter 14 (consisting of the pulse encoder 13 and the addition/subtraction counter 14) is automatically replaced with the learned absolute address stored in correspondence with the detected plate edge, the lifting carriage is adjusted to each stop height. When passing through, there will be almost no error between the pulse count value during learning (learning absolute address) corresponding to the actual height of the lifting carriage and the actual pulse count value in the moving distance measuring means. . Therefore, by controlling the lifting and lowering of the lifting carriage based on the difference between the stopping target value corresponding to the stopping target height and the pulse count value in the moving distance measuring means, the lifting and lowering carriage is moved to the target stopping height. can be stopped with high accuracy. That is, the greatest feature of the present invention is that when passing the lower edge of the detected plate on which the target stop position is located, when the object is rising, and the upper edge when it is falling,
In other words, the pulse count value is replaced with the learned absolute address stored corresponding to the edge of the detected plate immediately before reaching the target stop position, and therefore, the method disclosed in Japanese Patent Application Laid-open No. 140471/1983 When the disclosed technical idea is applied, when the elevating carriage passes the previous stop position, the pulse count value is stored in the learning absolute address stored corresponding to the previous stop position. Compared to the replacement method,
After the pulse count value is corrected, there are almost no errors that occur until the vehicle reaches the target stop position, making it possible to perform stop control with extremely high precision. Therefore, in the method of the present invention, instead of providing one detection point for each stop position as in the conventional method, two detection points, upper and lower, are required for each stop position. , the upper and lower edges of the detection plate are located in two places, and the detection plate itself is arranged so that the elevating carriage is at a predetermined stop position, as described in, for example, Japanese Utility Model Application Publication No. 58-45205. A detection plate attached to the lifting path side so that the two upper and lower detectors attached to the carriage side can simultaneously detect both the upper and lower ends when the carriage is stopped, i.e., general control that is not a pulse control method. Since it is possible to apply the method used in the method as it is, the method of the present invention can be easily implemented. Furthermore, according to the method of the present invention, the two upper and lower detection points required for each stop position are the upper and lower edges of one detection plate, and the center position of the upper and lower edges of the detection plate is set at the carriage stop position. As long as the accuracy of the mounting position of this detected board is improved, the pulse count value corresponding to the carriage stop position of each level can be calculated from the learned absolute addresses corresponding to the upper and lower edges of the detected board. Compared to the case where the pulse count value corresponding to the carriage stop position must be directly detected by learning lift operation of the lifting carriage, it is easy to obtain a very accurate pulse count value corresponding to the carriage stop position. Based on the pulse count value, the stop control of the elevating carriage can be performed with high precision.

[Brief explanation of the drawing]

Figure 1 is a front view illustrating the configuration of an automated warehouse, Figure 2 is a front view illustrating the relationship between the elevating carriage and the cargo storage section of the three-dimensional shelf, and Figure 3 is a front view of the detector, detection plate, and control system. FIG. 4 is a front view of the detection target plate, and FIGS. 5 to 7 are flowcharts for explaining the control method. 1... Three-dimensional shelf, 2... Load storage section, 3... Load receiver, 4...
Loading/unloading crane, 5... Load handling platform, 6... Load, 7... Running fork, 8... Lifting carriage, 9... Lifting drive motor, 10... Lifting chain, 11...
Control computer, 12...Elevation control device, 1
3...Pulse encoder, 14...Addition/subtraction counter, 15...Detected plate, 16...Guide column, 17...
Lower detected plate portion, 18... Upper detected plate portion, 1
9... Origin detection plate, 20, 21... Detector.

Claims (1)

[Claims] 1. A lifting distance measuring means is provided which replaces the position of the lifting carriage with respect to the origin with a pulse count value, and beside the lifting path of the lifting carriage, a height of the center of the vertical width is placed at a position corresponding to each stacked cargo storage section of the shelf. A lower detection plate corresponding to the stop height at the time of leaving the warehouse and a lower detection plate corresponding to the stop height at the time of warehousing are arranged side by side, and a detector is provided on the elevating carriage side to detect the detection plate. , the pulse count value in the movement distance measuring means when the detector detects the upper and lower edges of each detection plate is stored in advance as a learning absolute address, and during actual operation. , a pulse count value in the moving distance measuring means when the detector detects an edge of the detected plate is replaced with the learned absolute address, and a stop is calculated and stored in advance for each stop height. Stopping the lifting/lowering carriage based on the difference between the target value or the stop target value calculated each time based on a set of learned absolute addresses above and below the target stop height, and the pulse count value in the moving distance measuring means. A method for controlling the lifting and lowering of cargo in a crane for loading and unloading warehouses.