JPS5911520B2 - Control method during loading operations - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to automation of cargo handling operations using cargo handling vehicles such as forklifts.

Conventionally, cargo handling operations for loading and unloading loads onto and from the forks of a forklift have been performed manually by an operator.

The present invention has been made in view of this point, and an object of the present invention is to provide a control method for realizing complete automation of loading and unloading work by a cargo handling vehicle equipped with a cargo handling function such as a forklift. shall be.

According to the present invention, the traveling function and the cargo handling function of a cargo handling vehicle are configured to be automatically controlled, and by appropriately operating these functions under a series of sequential zero controls, complicated Perform cargo handling work automatically. A station is formed corresponding to a loading/unloading point of a load, such as a rack for storing the load or a loading/unloading port of a machine tool. The station can be composed of an excitation coil 5 and the like. A cargo handling vehicle such as a forklift is guided by a guide cable or the like and travels to a station corresponding to a loading/unloading point of the cargo to be worked, and the automatic cargo handling work according to the present invention starts from this station.

First, the vehicle is brought closer to a first predetermined position near the loading/unloading point from the station. At the first predetermined position, the height of the fork for loading or loading the load is automatically adjusted according to the height of the rack shelf or platform at the loading and unloading point. adjust. Next, the vehicle is brought closer to a second predetermined position that is closer to the unloading point, the height of the fork is further finely adjusted at this position, and the load is unloaded to the unloading point/or the load is moved from the unloading point onto the fork. Load cargo. That is, when the vehicle is located in the second position, the loaded fork is located above a shelf or platform at the unloading point and/or the fork is located in a pallet placed with the load on the shelf or platform. has entered, and at this point a fine adjustment of the height of the fork will place the load completely on the shelf or platform and/or the load will be completely loaded onto the fork. The vehicle is then returned towards the station and the height of the fork is lowered to its original steady height. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the embodiments described below, an existing forklift is used as a cargo handling vehicle, and devices and detection devices (such as a pick-up sensor) necessary for controlling unmanned driving and loading and unloading work are installed on the forklift. I'll post it on the tower.

Figure 1 shows a block diagram of the main control system installed on the forklift. In FIG. 1, an inductive signal sensor 10
is used when the forklift automatically travels along the guide cable, and is not used during the cargo handling sequence.

Four pick-up coils installed at the four corners of the wharf can be used as the sensor 10, and as is well known, they are used in the guidance travel control device 11 to detect the lateral displacement and attitude angle of the vehicle with respect to the guidance cable. be done. The guided travel control device 11 receives the output of the sensor 10 and operates a start control actuator 12, a braking control actuator 13, a steering control actuator 14,
Control signals for driving the vehicle speed control actuator 15, the forward/backward control actuator 16, etc. are appropriately supplied to realize unmanned driving along the guide cable. The station detection sensor 17 is a sensor that detects the station position described above.

Further, the cargo handling work fixed position detection sensor 18 is a sensor that detects the position of a coil for operation command and fixed position Fik recognition, which will be described later. The cargo handling work control device 19 is a circuit that controls cargo handling work according to a predetermined sequence. When the vehicle reaches a station to be stopped, the guided travel by the guided travel control device 11 is canceled, and the cargo handling work by the cargo handling work control device 19 is started. The work session begins. As will be described later, in the cargo handling work sequence, the cargo handling work control device 19 controls the start control actuator 12 and the braking control actuator 1.
3 and the forward/reverse control actuator 16, and operates the turning control circuit 20 and fork height control circuit 21 to control the steering control actuator 14.
and controls the driving of the fork lift height control actuator 22. The fork height sensor 23 detects the height of the raised fork and applies a feedback signal H to the height control circuit 21. Further, if necessary, the fork can be configured to control the tilt angle (front and rear inclination), and the tilt control circuit 24 is operated by the control device 19.
A drive signal is given to the fork tilt actuator 25. At this time, the fork tilt angle sensor 26
A feedback signal is provided from the control circuit 24 to the control circuit 24. For example, if you want to tilt the fork slightly backwards when loading a load onto the fork, it is recommended to perform tilt angle control. However, this tilt angle control does not need to be performed in particular. As actuators for various autopilots, any type such as electric, hydraulic, or pneumatic type can be used.
FIG. 2 is a schematic plan view illustrating the state of cargo handling work according to a predetermined sequence.

The forklift FL, which has been guided by the guidance cable 27 and traveled in the direction of the arrow 28 (with the fork FK behind it), stops at the station ST, and is controlled by the guidance travel control device 11 (FIG. 1). When it is released, the cargo handling control device 19 operates instead and performs automatic cargo handling in the order described below. The station ST is composed of appropriate coils, and a central control device (not shown) energizes the coil of the station where the vehicle is to be stopped, and the energized station coil is sent to the station detection sensor 17 (second 1) is detected on the vehicle side.

Of course, the station may be configured in a manner other than the above. In FIG. 2, from station ST to rack 29 (
That is, the route shown by the broken line connecting the cargo loading and unloading points represents the route along which the cargo handling work sequence is performed.

At the beginning of this cargo handling work sequence route, from the front of the rack 29 (loading/unloading port) 29a to the fork F
An operation command and position confirmation coil 30 is arranged at a distance x, which is slightly longer than the length of K's claw. In addition, as shown in the schematic plan view of the forklift FL in Figure 3, the forklift FL's body is located at a distance equal to or slightly shorter than the distance X from the tip of the fork FK's claw. A first fixed position detection sensor 18a is located at the position, and a fork F is located behind the first sensor 18a.
A second fixed position detection sensor 18b is attached at a position separated by a length X'' which is approximately the same length as the length of K's claw.
These sensors 18a, 18b correspond to sensor 18 in FIG. The cargo handling sequence consists of the following eight steps.

In step 1, the forklift FL stopped at the station ST is moved forward while turning 90 degrees to the right or left depending on which direction the rack 29 is located (the forklift FL is driven with the fork FK facing forward). Move the fork to the position indicated by 31.

The position indicated by the solid line 31 is the first fixed position, and in this position, the first sensor 18a of the vehicle is connected to the fixed position confirmation coil 3 on the ground.
Almost coincides with the 0 position. When the vehicle reaches the first fixed position indicated by the solid line 31, the process proceeds to step 2. The reason why the vehicle was turned 90 degrees in step 1 is that the direction of the vehicle FL stopped at the station ST is the front 2 of the rack 29.
This is because the common and efficient arrangement of the rack 29 is parallel to the guide cable 27a.
This is because a large number of them are arranged along a running course formed by the above method. Therefore, if the front surface 29a of the rack 29 is not parallel to the direction of the forklift stopped at the station ST, the step 1 is caused to turn at an appropriate angle or travel straight. In step 2, the vehicle stops traveling and raises the height of the fork FK of the forklift FL to the first specified height H2 at the first fixed position 31.

The height of the first designated height H is approximately 2 degrees from the fork FK.
The case of unloading (storing) the load from the rack 29 is different from the case of loading the load from the rack 29 onto the fork FK.

As shown in FIG. 4a, the claw of the fork FK is inserted into the pallet 34 on which the load 33 is placed, and the load is placed on the forklift, and then the pallet 34 and the load are placed on a certain shelf 29b of the rack 29. When unloading the load 33, use the shelf 29b
The height LH+h'', which is the sum of the height LH and the minute height h, becomes the first specified height H2.Also, as shown in FIG. When loading on the shelf 29b, the height is approximately equal to the height LH of the shelf 29b (
To be exact, the height to the insertion port of pallet 34) is the first
The specified height is H2. In step 3, the first specified height H
While maintaining the forklift FK at a height of 2, the forklift FL is moved forward, and the forklift
Move the vehicle to the fixed position. At the second fixed position 32, the second fixed position detection sensor 18b on the vehicle side almost matches the position of the fixed position confirmation coil 30 on the ground. In this second home position 32, the fork FK is located at the loading and unloading point, ie on a certain shelf 29b of the rack 29. Specifically, in the case of unloading (Fig. 4a), the load 33 loaded on the fork FK is located above the shelf 29b, and in the case of loading (Fig. 4b), the load 33 is placed on the shelf 29b. 29b
A fork FK is in pallet 34 placed on Q. In step 4, while the forklift is stopped at the second fixed position 32, the height of the fork FK is finely adjusted and raised/lowered to the second designated height H.

The height of the second specified height H, is different when unloading a load from the 7 Oak FK and when loading a load onto the Fork FK.

When unloading, the first specified height H2 is LH + H7.
Therefore, the second specified height H3 is approximately the height L of the shelf 29b.
H (specifically, slightly higher than the height of the shelf 29b), and the load 33 and the pallet 34 are placed on the shelf 29b. When loading a load, since the first designated height H2 was approximately LH, the second designated height H3 was set to "LH+h", and the load 33
together with the pallet 34. In step 5, the forklift is driven backward while maintaining the second designated height H of the fork FK, and the vehicle is returned from the second home position 32 to the first home position 31.

At this time, in the case of unloading, the fork FK is pulled out from the pallet 34 placed on the shelf 29b, and the load 33 is stored on the rack 29 (shelf 29b). Further, in the case of loading, the load 33 loaded on the fork FK is carried away from the rack 29 (shelf 29b) via the pallet 34. Next, in step 6, while the forklift is stopped at the first fixed position 31, the height of the fork FK is lowered to the steady height H1. The steady height H, is a height suitable for stabilizing the center of gravity of the forklift FL during normal driving, and is generally the height at which the claws of the forklift FK are located relatively (or even closest) to the ground. . In step 7, the height of the fork FK is maintained at a steady height H, and while driving backward, the steering angle is tightened to turn 90 degrees in the same direction as in step 1, and the vehicle is returned to the station ST position.

When the turning is completed (the forklift FL has almost returned to the position of the station ST), the process proceeds to step 8. In step 8, an instruction is given to end the cargo handling sequence, and the operation of the guided travel control device 11 is restarted.

FIG. 5 shows an example of the configuration of the cargo handling control device 19 that controls the cargo handling sequence as described above.

In Fig. 5, the counter 35 is used to specify the step to be executed and advance the sequence, and is set to 0 during guided travel.When the count is 0, the counter 35 is set to 0. Output S that specifies signal 1 (high level)
It is becoming. The counter 35 advances the count every time one pulse is supplied from the pulse generating circuit 36. Count value 1~
8 corresponds to steps 1 to 8, and each step progresses each time the count advances. Signals S and ~S8 generated in response to count values 1 to 8 are signals that designate steps 1 to 8, respectively, and when the content of the signals S1 to S8 is 12, that . Specify the step. Signal S designating step 0. enables the AND circuit 37. When the forklift FL traveling along the induction cable reaches the station where it should stop, the output of the station detection sensor 17 (Fig. 1) becomes 1'', which operates the AND circuit 37 and turns the OR circuit 38 on. The signal 1 is applied to the pulse generation circuit 36 via the pulse generation circuit 36.The pulse generation circuit 36 generates one pulse and drives the counter 35.As a result, the count value of the counter 35 becomes 1, and the signal specifying step 1 is applied. S1 becomes ゞ 1″. Of course there are other outputs S. , S2
~S8 is "0". In this way, the cargo handling sequence is started. The signal S1 designating step 1 changes the signal H1 to X' 1 " through the OR circuit 39, and designates the height of the fork FK to be the steady height H1.

Further, the forward/reverse instruction signal F/R is sent via the OR circuit 40.
is set to ``1'' to instruct forward travel. The signal F/R is applied to the forward/reverse actuator 16 (FIG. 1) and
'' specifies forward travel, and 0'' specifies reverse travel. Further, the output of the OR circuit 40 is passed through the OR circuits 41 and 42 to set the driving instruction signal START to 1''.The signal START is applied to the start control actuator 12 (Fig. 1), and when the signal is at 1'', the vehicle is activated. Start and get running. Further, the output of the OR circuit 41 sets the count permission signal CE to 1'', making the reversible counter 43 (FIG. 6) of the swing control circuit 20 ready for counting, and at the same time, the output of the OR circuit 40 sets the count permission signal CE to 1''. U/D is set to 1'' to put the reversible counter 43 in an increment mode. FIG. 6 shows →Ij of the turning control circuit 20, which controls the turning of the vehicle and also controls the traveling of the vehicle to the first fixed position 31 and the second fixed position 32 (FIG. 2). .

That is, as will be described later, the steering angle Y8 of the vehicle during a turn is given by a function of the travel distance xl of the vehicle counted by the reversible counter 43. It is confirmed whether the vehicle has reached the first and second fixed positions 31 and 32 by using the calculated distance. Whether or not the first and second fixed positions 31 and 32 have been reached can also be confirmed by the first and second sensors 18a and 18b and the fixed position confirmation coil 30, depending on the distance and the sensor. By confirming both, the accuracy of vehicle stop position control during cargo handling operations is improved. Note that the automatic running/sequence instruction signal AUT/SEQ is the signal S at step O. This signal A becomes '1''.
UT/SEQ is added to the reset input of the reversible counter 43, and resets the contents of the counter 43 to O at step O. Therefore, when the signal CE and the signal U/D become "1" at step 1, the reversible counter 43 becomes O.
Start addition counting from. A pulse CP proportional to the traveling distance obtained from a vehicle speed detection sensor (not shown) of the forklift FL is supplied to the counter 43 as a count pulse. Therefore, the counter 43 counts the distance traveled by the forklift in the cargo handling sequence. counter 4
The count output of 3 is applied to a digital-to-analog converter 44 to obtain an analog signal proportional to the travel distance Xl of the forklift.

The steering angle Y8 in a turn is given by a function of the travel distance Xl of the forklift. This function has a relationship as shown in FIG. 7, for example, and the function generator 45 outputs an analog signal specifying an appropriate steering angle Ys according to the value of the travel distance X1 input to the function generator 45. be done. A steering angle detection signal S is fed back from a steering angle detector (not shown) provided in connection with the steering operating mechanism of the forklift, and the command steering angle Ys and the steering angle feedback amount S are The servo amplifier 46 is driven according to the deviation from the
4 (Fig. 1) and also controls the steering drive.

In this way, the 90 degree turn is controlled according to a predetermined function. Note that the polarity of the command steering angle Ys given from the function generator 45 is reversed for right-hand turns and left-hand turns, and the command for the turning direction is controlled by appropriate central control when the vehicle reaches the station. Control device (not shown)
given from. The content of the function for steering control is, for example, to gradually increase the angle from angle 0 as the travel distance Xl progresses, and to set the maximum steering angle SMAX.
When the maximum angle SMAX is reached, the maximum angle SMAX is maintained for a while, and then the steering angle is gradually returned as the travel distance Xl progresses, and when the travel distance reaches L1, the steering angle Ys completely returns to O degrees. Therefore, according to this control, the turning will end when the travel distance from the start of the turning reaches L. The fact that the mileage is L is,
This can be known from the count value of the reversible counter 43.

It is detected using an appropriate logic circuit that the count value of the counter 43 has reached a value corresponding to the distance L, and the signal L is set to 1.
``'' and added to the AND circuit 47 (FIG. 5). In FIG. 6, since the count value 32 corresponds to the distance L1, the data of the sixth bit having a weight of 32 is shown to be used as the signal L1. According to this control, when the vehicle finishes turning, it is positioned at the first fixed position 31, so that the first fixed position sensor 18a
is applied to the detection circuit 48 so that the vehicle is in the first home position 3.
It is detected that the number has reached 1. The output of the detection circuit 48 and the signal L1 are both applied to an AND circuit 47,
Furthermore, the signal S1 of step 1 is applied to an AND circuit 47 via an OR circuit 49. Therefore, the AND circuit 47
When all of the input conditions are satisfied, the vehicle is in the first fixed position 31 and is facing exactly the front surface 29a of the rack 29.
At this time, the counter 35 is driven by one pulse from the pulse generating circuit 36, and the process proceeds to step 2. Step 2
When the signal S2 designating the first designated height H2 becomes "1", the signal H2 designating the first designated height H2 becomes "17" via the OR circuit 49. At the same time, the signal S1 becomes ゞo'', so the OR circuit 42
The output becomes ゜02, and the stop command signal STOP becomes "1f" via the inverter 50. Therefore, the brake control actuator 13 (FIG. 1) is driven, and the vehicle stops at the first fixed position 31. Signals H, , H2, and H3 specifying the height of the fork FK are applied to a fork height control circuit 21 shown in FIG.

In the circuit 21, the height of the steady height H1 is set by a variable resistor R1. For example, if the rack 29 has three shelves, the height of each shelf LH, , LH2, LH3 is set by a variable resistor, respectively. It is set by VR2, VR3, and VR4, and the minute height h is set by a variable resistor VR5. Height LHl~LH,
The movable contacts of the variable resistors VR, -R4 that have been set are connected to the rotary switch 51. The operation designation and position confirmation coil 30 (Fig. 2) is given a frequency signal from a central management control device (not shown) that instructs the height of the shelf at which loading and unloading of goods should be carried out. is detected by the first sensor 18a, and a relay or the like (not shown) is operated according to the commanded height to switch the contact point of the rotary switch 51. Further, a frequency signal is supplied to the coil 30 to instruct either to unload a load from the fork FK (unload) or to load a load to the fork FK, and this frequency is 1 is picked up by the sensor 18a, and a relay or the like (not shown) is operated in accordance with the content of the command to change the contact point of the switch 52. The switch 52 is connected to the terminal L for loading, and to the terminal UL for unloading. Now, in step 2, the signal H is S11''
Therefore, the output of the NOR circuit 53 becomes "O", and the transistor 54 is turned off.

Therefore, the height selected by the rotary switch 51 (LH
, ~LH) is led to line 55. At this time, if you unload the cargo (anchored)
, the voltage of the terminal UL is SO'' and the signal speed is 17, so the output of the NOR circuit 56 becomes 17, and the NOR circuit 5
The output of transistor 7 becomes "0" and transistor 58 is turned off. Therefore, a signal (voltage) representing the minute height h is led to the line 55 and added to the shelf height LH (any one of LHl to LH), and "LH+h" is the command height signal H.
It is input to the servo system 59 as a set. In addition, when loading a load (loading), the switch 52 is connected to terminal L, so the outputs of the NOR circuits 56 and 60 are both "O".
g, the transistor 58 is turned on. Therefore, the minute height signal h is not guided to the line 55, but is directed to the specified shelf height L.
Only the H signal is sent to the servo system 5 as the command height signal Hset.
Join 9. The servo system 59 receives the height command value Hset applied from the line 55 and the fork height sensor 23 (Fig. 1).
The fork height control actuator 22 is based on the deviation of the fork height from the feedback signal H.
(Fig. 1) to set the height of the fork FK to the specified height H. In addition, the actual height H and the height command value Hset
The deviation (Hset-H) from the output signal is outputted and supplied to the circuit shown in FIG. The deviation (Hset-H) is added to the window comparator 61, and if the deviation falls within the tolerance range set by the comparator 61, it is assumed that the specified height H has been reached, and the comparator 61 outputs "1". , sets the output of the AND circuit 62 to '1''.

Note that the AND circuit 62 receives a signal S specifying step 2.
2 is added from the OR circuit 100. In this way, the counter 35 is activated and the process proceeds to step 3. Step 3
When the signal S, which specifies 112, the signal H, maintains 1'' through the OR circuit 49, thereby maintaining the first specified height H,.

Further, the signal F/R of the OR circuit 40 is set to 12, and the signal STARTt!:ゞ1 is output via the OR circuits 41 and 42.
” and move the forklift forward. At the same time,
Signal U/D and signal CE become "1", and the reversible counter 43 of the turning control circuit 20 is driven to further add and count the travel distance on top of L1. Since the output X1 of the digital-to-analog converter 44 has already exceeded the distance L1, no output is generated from the function generator 45, and the forklift runs straight. When the forklift reaches the second home position 32 (FIG. 2), the second sensor 18b almost coincides with the home position confirmation coil 30, and the output of the detection circuit 63 (FIG. 5) becomes "
1''. Also, the forklift moves to the second fixed position 3.
2, the count value of the reversible counter 43 is the distance L.
2, and this is detected by the AND circuit 64. In the example of FIG. 6, the count value corresponding to distance L2 is 50, so the second
The data of the th bit, the 5th bit, and the 6th bit are added to the AND circuit 64, and the signal L, indicating that the distance L has been reached, is set to 1''.Signal L
2 and the output of the detection circuit 63 are added to the AND circuit 65,
This AND circuit 65 is enabled to operate by the signal S of step 3. Therefore, when the vehicle reaches the second home position, the output of the AND circuit 65 becomes "1" and the counter 35 is advanced by one step. When the signal S4 designating step 4 becomes 11, the signal H, designating the second designated height H3 via the OR circuit 66 becomes S11''.

At the same time, the signal S becomes 02, so the signal START
becomes O'', the signal STOP becomes 11'',
The vehicle stops at a second home position 32. Height control circuit 21
When the signal H becomes "12", the output of the NOR circuit 53 becomes "0" and the transistor 54 is turned off.

However, transistor 58 operates in the opposite manner as at the first designated high, H. In other words, when unloading the load, the terminal UL of the switch 52 is ``O'', the terminal L is ``1'', the signal 7 is ``1'', and the signal is ``o'', so the NOR circuits 56, 6
0 both output "0", and the transistor 58 is turned on. Therefore, the designated height value Hset is only the height LH of the designated shelf, and the height of the first designated height H2 "LH+h".
'' is lowered by a minute height h. Also, when loading a load, the terminal L becomes ``o'', so the output of the NOR circuit 60 becomes ゛ 1
The output of the NOR circuit 57 becomes "O", and the transistor 58 is turned off. Therefore, if the height command value Hset is L
H+h'', which is higher than the height LH at the first specified height H2 by the minute height h. Therefore, in this step 4, in the case of unloading, the load 33 is lower than the height LH at the first specified height H2.
The fork FK was placed on the shelf 29b, and the fork FK was still in the bullet 34. Further, in the case of loading, the fork FK that entered the pallet 34 at the step 3 lifts the load 33 together with the pallet 34 above the shelf 29b. When the deviation (Hset-H) falls within the permissible error range, the output of the AND circuit 62 becomes 1'' as described above, and the counter 35 advances to step 5.
The signal S5 representing step 5 changes the signal START to "1" via the OR circuits 41 and 42, thereby setting the vehicle in a running state.

However, since the output of the OR circuit 40 is "ol", the signal F
/RbaO'', commanding backward travel. Therefore, the unloaded/loaded forklift is in the first position.
It retreats to its home position 31. At this time, the signal U/D is 0.
'', which instructs the reversible counter 43 to perform a subtraction operation.
Therefore, when moving backward by the same distance as the distance moved forward in step 3, the count value of the counter 43 becomes a value corresponding to the distance L, and since the first sensor 18a almost coincides with the position of the coil 30, the AND circuit is activated. The output of 47 becomes 1, and the counter 35 is advanced by 1 step. When the signal S6 designating the step 6 becomes "1", the signal H, designating the steady height H1, becomes "1" via the OR circuit 39.
becomes.

At the same time, the signal START becomes もO'', and the signal STOP
becomes ``1''5, so the vehicle stops. When the signal H1 becomes ``1I'', the transistor 67 shown in FIG. Therefore, the height of the fork FK is lowered to the steady height H1, and when the output of the AND circuit 62 becomes "1", the counter 35 advances to step 7.
The signal S7 specifying step 7 is sent to OR circuits 39, 41,
42, and sets the signals H, START, and CE to 1'', respectively.

At this time, the signal F/Rbao'' specifies backward travel, and the signal U/D commands subtraction with "o". Therefore, the vehicle starts traveling backward, and the counter 43 changes from the value of distance L1. Subtraction is started toward O. When the output X1 of the DA converter 44 becomes smaller than the value corresponding to the distance L1, the function generator 45 generates a function of the steering angle Ys in the opposite direction to that in step 1. is generated, the vehicle turns toward the station ST position while traveling backwards.When the count value of the counter 43 reaches O, it means that the vehicle has returned to the station ST position (that is, the starting point of the sequence). , the NOR circuit 68 detects this and sets the signal L to "1". Signal L. is added to the AND circuit 69 in FIG. 5, causing the AND circuit 69, which had already been activated by the signal S of step 7, to output "1".The counter 35 is thus advanced to step 8. The signal S8 designating 8 resets the counter 35.

When the counter 35 is set, the signal S at step 0
. becomes "1", and the signal AUT/SEQ becomes "17", instructing to carry out guided travel along the guiding cable 27. Therefore, the sequence ends.By the way, in order to prevent double storage, In addition, it is possible to prevent the fork height command signal from being applied to shelves on which goods are already stored.

For example, as shown in FIG. 9, each shelf 291 of the rack 29,
292, 293, load detection switch 70,
71 and 72 are provided. This switch 70-72 is on shelf 29
1 to 293 are opened when a load is placed on them, and closed when no load is placed on them. and,
Three coils 301 and 302 are used for the fixed position confirmation coil 30.
, 303, and each coil 301-303 and switch 70-72 are connected in series in one-to-one correspondence.
These coils 301 to 303 are connected to the rotary switch 5.
For example, when exciting the coil 301 to specify the shelf 291, if a load is placed on the shelf 291, the switch 70 is applied. Open, the coil 301 is not excited. Therefore, no shelf height command is given to the forklift, and the cargo handling operation is brought to an emergency stop. In this way double storage is prevented. As explained above, according to the present invention, cargo handling using a cargo handling vehicle such as a forklift can be completely automated according to a predetermined sequence, promoting labor saving in automated warehouses, factories, etc. It becomes possible to do so.

In addition, by setting up a cargo handling area separate from the driving route, a large amount of cargo can be stored in a concentrated manner.Moreover, since this cargo handling area is far from the driving route, the cargo placed there can be placed in a location separate from the driving route. There will be no obstruction. Of course, the details of the cargo handling sequence are not limited to those shown in the above embodiment, and can be modified in various ways.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a control device mounted on a forklift used in the present invention, Fig. 2 is a schematic plan view illustrating a cargo handling work sequence, and Fig. 3 is a block diagram showing an example of a control device mounted on a forklift used in the present invention. A diagram explaining the installation position of the second fixed position detection sensor, FIG. 4 is a schematic side view explaining the first specified height H, which specifies the fork height during loading/unloading, and FIG. 5 1 is a block diagram showing an example of the cargo handling control device shown in FIG. 1, FIG. 6 is a block diagram showing an example of the turning control circuit shown in FIG. 1, and FIG. 7 is a block diagram showing an example of the turning control circuit shown in FIG. FIG. 8 is a graph showing an example of the function, FIG. 8 is a block diagram showing an example of the fork height control circuit of FIG. 1, and FIG. 9 is a schematic diagram illustrating the double storage prevention means.

Claims (1)

[Scope of Claims] 1. In a cargo handling system using a cargo handling vehicle that travels along a guidance cable laid in a workplace, the steering angle of the cargo handling vehicle is controlled according to a preset program; A first step of causing the cargo handling vehicle to move away from the guide cable from a station provided on the guide cable to a predetermined position near a load storage platform such as a rack that is disposed at a location away from the guide cable.
a second step of causing the cargo handling vehicle to unload or load cargo onto the storage platform at the predetermined position; and a third step of causing the vehicle to return to the station after completing the work. A cargo handling control method that executes the following steps in sequence. 2 The second step is a step of controlling the cargo handling fork of the vehicle at the first predetermined position to a predetermined height according to the height of the storage platform and loading or unloading, and then a step of driving the cargo handling vehicle to a second predetermined position so that the fork is positioned above the storage platform; and a step of reducing the height of the fork at the second predetermined position according to loading or unloading. 2. The cargo handling work control system according to claim 1, further comprising the step of moving the cargo upward or downward by the amount of the load and loading the load on the fork or placing the load on the storage platform. 3 The first step is to control the steering angle of the cargo handling vehicle in accordance with the travel distance of the cargo handling vehicle, and to turn the cargo handling vehicle from the station position toward the storage platform. A cargo handling operation control method according to claim 1. 4. The cargo handling operation according to claim 1, wherein the storage platform is provided with an excitation coil near the storage platform, and the excitation coil notifies the vehicle of its stop position and also commands the height of the storage platform. control method.