JPH07210245A - Transfer control method - Google Patents

Abstract

PURPOSE:To prevent the unnecessary deceleration of a truck and to improve the transfer efficiency by narrowing previously a sensor area before a sensor detects a fixed object when this object excluded out of a movable range of a transfer mechanism enters a detecting range of the sensor. CONSTITUTION:The operation of a sensor 2 is started before a truck 1 runs, and the sensitivity of the sensor 2 is set at 'strong'. Under such conditions, the running of the truck 1 is started. Then the presence of absence of an obstacle is decided in an area S of the sensor 2 while the truck 1 is running at a speed alpha. When no obstacle is recognized in the range S, the truck 1 continuously runs at the speed alpha. Then it is decided whether the truck 1 reached its target position. If not reached, the sensitivity of the sensor 2 is switched from 'strong' to 'weak' when a position sensor 3 of the truck 1 detects a switching position set on a transfer rail 11. Thus the sensor area is changed to a weak area S' and the truck 1 is stopped when the sensor 3 detects a stop position.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transportation control method for a transportation mechanism that travels on a fixed track and is movable within a fixed range to transfer an article to a predetermined position.

[0002]

2. Description of the Related Art In the automatic transfer of a manufacturing line, there is a case where a so-called tracked transfer mechanism is used in which predetermined parts or products are mounted on a carriage and traveled on a fixed track. As shown in the schematic view of FIG.
Is traveling on a constant transport rail 11, a movable range T of the trolley 1 is determined, and within this movable range T, for example, parts are transported from a warehouse to a plurality of devices A to C. Further, the cart 1 is provided with a sensor 2, and a certain area on the traveling direction side is set as a detection area R of the sensor 2 to detect whether or not there is an obstacle (including intrusion of a person) in this area. There is. When an obstacle enters the detection area R, the traveling speed of the truck 1 is reduced, and when the truck 1 and the obstacle approach each other, the truck 1 is stopped.

FIG. 5 is a flow chart for explaining a conventional carrying control method in the carrying mechanism shown in FIG. For example, when a part or the like is transported from the warehouse to the device C, first, a predetermined part is taken out from the warehouse and placed on the carriage 1, and in this state, the operation of the sensor 2 provided on the carriage 1 is started (step 5a). . Next, the traveling of the carriage 1 is started (step 5b), and the carriage 1 is moved in the direction of the device C along the transport rail 11 at a predetermined speed.

The sensor 2 detects whether or not an obstacle is present in the detection area R on the traveling direction side of the carriage 1, and a predetermined arithmetic unit judges the presence or absence of the obstacle based on the detection signal (step 5c). ). If there is no obstacle, the determination in step 5c is No, and the trolley 1 is allowed to travel toward the target position. Further, when an obstacle enters the detection area R of the sensor 2 and the sensor 2 detects it while the vehicle 1 is traveling, the determination in step 5c is Yes, and the traveling speed of the vehicle 1 is reduced (step 5e). . Although not shown in FIG. 5, when the obstacle and the trolley 1 are closer to each other, the trolley 1 is stopped, and when the obstacle is eliminated, the original speed is restored.

The determination of the presence or absence of such an obstacle and the speed control are performed until the carriage 1 reaches the target position (step 5).
d). Then, when the trolley 1 reaches the position of the device C which is the target position, the traveling of the trolley 1 is stopped (step 5
f) After that, the operation of the sensor 2 is stopped (step 5).
g). In this way, parts and the like are transported from the warehouse to the device C, for example. Note that this transfer control is the same even if the transfer is not performed from the warehouse to the device C.

[0006]

However, such a transfer control method has the following problems. That is, as shown in the schematic view of FIG. 6, when the carriage 1 moves to the vicinity of the end of the movable range T, for example, the wall 12 detects the detection region R of the sensor 2.
Therefore, the wall 12 is regarded as an obstacle and the speed of the carriage 1 is decelerated in the above-described transfer control method.

[0007] Figure 3 is a graph showing the change of the traveling speed of the trolley 1, which indicates the speed of the truck 1 during traveling from the position P ₀ to P _1. That is, the position of the warehouse, which is the traveling start position of the carriage 1, is set to P _0, and the device C, which is the stop position, is set.
When the position of P is set to P ₁ , the speed of the trolley 1 is the position P of the warehouse.
_It accelerates from ₀ and reaches speed α, and then runs at a constant speed for a while. Then, at the point P ₃ where the wall 12 enters the detection area R of the sensor 2, the speed decelerates to become the speed β and arrives at the position P _{1 of the} device C (see the broken line in the figure).

However, in actuality, the wall 12 is a fixed object outside the movable range T of the carriage 1 and does not hinder traveling. In other words, the speed that is reduced by considering an object that does not hinder the traveling of the trolley 1 as an obstacle, which leads to a decrease in transport efficiency. Further, in addition to the wall 12, for example, when the devices A to C have a projecting portion and the projecting portion falls within the detection region R of the sensor 2, the speed of the trolley 1 is reduced, which causes a decrease in transport efficiency. ing.

[0009]

SUMMARY OF THE INVENTION The present invention is a transport control method which has been made to solve such a problem. That is, the present invention, in a transport mechanism that travels on a certain track and is movable within a certain range, detects a sensor within a predetermined detection region on the traveling direction side of the transport mechanism, and detects the object in the detection region. This is a transport control method that controls the traveling speed of the transport mechanism based on the presence / absence of a transport mechanism, and when a fixed object existing outside the movable range of the transport mechanism falls within the detection range of the sensor, before the sensor detects this fixed object in advance. This is a method that narrows the detection area. In addition, when the detection area is narrowed, it is also a conveyance control method that prevents fixed objects from entering the detection area after the narrowing.

[0010]

By narrowing the detection area before a fixed object such as a wall enters the detection area of the sensor, the sensor does not detect the fixed object and the transport mechanism does not unnecessarily decelerate. Also, by preventing fixed objects from entering the narrowed detection area, the sensor will not detect fixed objects until the transport mechanism reaches the target position, and unnecessary deceleration will occur other than detecting obstacles. Disappear.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the transport control method of the present invention will be described below with reference to the drawings. The transport control method of the present invention is a method for controlling the transport mechanism shown in FIG. 4, and is particularly characterized in the control when a fixed object outside the movable range T of the carriage 1 enters the detection area R of the sensor 2. . The movable range T here
In addition, the movable range of a transfer arm (not shown) provided on the carriage 1 is included.

FIG. 1 is a flow chart for explaining the transfer control method of the present invention, FIG. 2 is a schematic diagram for explaining sensitivity switching of a sensor, and FIG. 3 is a graph for explaining changes in the traveling speed of a carriage. That is, according to this conveyance control method, while the carriage 1 shown in FIG. 2 travels on the conveyance rail 11, the sensitivity of the optical sensor 2 is switched at a predetermined position to change the detection area from the strong area S to the weak area S ′. Is a method of controlling the speed of the carriage 1.

The carriage 1 is provided with, for example, an optical position detection sensor 3 so that the position of the carriage 1 on the transport rail 11 can be grasped. Below, the control method while the carriage 1 moves from the traveling start position on the transport rail 11 to the stop position near the wall 12 will be described with reference to FIG. First, the operation of the sensor 2 is started (step 1a) before the carriage 1 is run, and the sensitivity of the sensor 2 is set to "strong" (step 1b). As a result, the sensor 2 detects the obstacle by using the strong area S as the detection area.

Next, the trolley 1 with the sensor 2 activated.
Starts traveling (step 1c). As shown in FIG. 3, the carriage 1 moves from a position P ₀ (running start position) to accelerate from a stopped state to reach a speed α. Then, while the trolley 1 travels at the speed α, it is determined whether or not an obstacle exists in the strong region S which is the detection region of the sensor 2 (step 1d).

When there is no obstacle in the strong area S, the determination in step 1d is No, and the trolley 1 is run at the same speed α to determine whether or not the vehicle has arrived at the target position (step 1e). . In addition, while the carriage 1 is traveling, the sensor 2
When an obstacle enters the strong area S which is the detection area of the sensor 2 and the sensor 2 detects this, the determination in step 1d is Yes, and the traveling speed of the carriage 1 is decelerated (step 1
f). Although not shown in FIG. 1, when the obstacle and the trolley 1 are closer to each other, the trolley 1 is stopped, and after the obstacle is eliminated, the original speed α is restored.

If the trolley 1 has not arrived at the target position (No in step 1e), or step 1f
After the deceleration process of step 1 is performed, it is determined whether the truck 1 has reached the switching position (step 1g). This switching position is provided in advance at a position where the position detection sensor 3 can detect before the wall 12 enters the strong region S which is the detection region of the sensor 2. If the position detection sensor 3 of the carriage 1 has not detected the switching position provided on the transport rail 11, the determination is No and the process returns to step 1d. On the other hand, when the position detection sensor 3 of the trolley 1 detects the switching position, the result is Yes and the sensitivity of the sensor 2 is set to "strong".
To "weak" (step 1h).

When the sensitivity of the sensor 2 is switched from "strong" to "weak", the detection area becomes the weak area S ', and the sensor 2 does not detect the wall 12. That is, when the sensitivity of the sensor 2 becomes “weak” at the position of the arrow shown in FIG. 3, the carriage 1 moves to the position P ₃ (when the detection region is the strong region S, the sensor 2 moves to the wall 1).
When the vehicle reaches the position (2), the wall 12 is not detected and the vehicle travels at the speed α.

When the trolley 1 arrives at the target position, the determination in step 1e becomes Yes and the trolley 1 stops traveling (step 1i). The trolley 1 is at the position P shown in FIG.
Speed control is performed so that deceleration starts at ₂ and stops at position P ₁ . That is, the stage where the position detection sensor 3 of the trolley 1 shown in FIG. 2 starts deceleration for stopping before the stop position is detected (position P ₂ shown in FIG. 3) and the position detection sensor 3 detects the stop position. The trolley 1 stops at.

As described above, by switching the sensitivity of the sensor 2, the wall 12 or the like, which is a fixed object, is not regarded as an obstacle, the carriage 1 is not unnecessarily decelerated, and efficient transportation can be performed. become. In addition, a weak area S ′, which is a detection area when the sensitivity of the sensor 2 is set to “weak”
If the setting is made so that the wall 12 does not enter the inside, the sensor 2 does not detect the wall 12 until the carriage 1 arrives at the target position, so that the carriage 1 can be transported more efficiently.

Although the wall 12 has been described as an example of a fixed object in the present embodiment, the present invention is not limited to this. That is, when there is a fixed object (such as a protruding portion of the devices A to C) which is outside the movable range T of the trolley 1 shown in FIG. 4 and enters the detection region R (strong region S shown in FIG. 2) of the sensor 2. Can be treated similarly. That is, the position of such a fixed object is determined in advance by the layout of the warehouse and the devices A to C. Therefore, if a switching position for switching the sensitivity of the sensor 2 from “strong” to “weak” is provided before the fixed object enters the strong region S of the sensor 2 while the vehicle 1 is traveling, the sensor 2 will be fixed. You can run without detecting.

In the present embodiment, an example has been described in which the position detection sensor 3 switches the sensitivity of the sensor 2 based on whether or not the switching position is detected, but the present invention is not limited to this, and for example, Alternatively, the traveling distance may be calculated based on the traveling speed and traveling time of the carriage 1, and the sensitivity of the sensor 2 may be switched when the carriage 1 reaches a preset position based on the calculation result.

[0022]

As described above, the transport control method of the present invention has the following effects. That is, according to this transport control method, a fixed object such as a wall is not regarded as an obstacle, and unnecessary deceleration of the carriage is eliminated. For this reason,
It is possible to improve the transportation efficiency by shortening the transportation time of the carriage. Moreover, even if the sensitivity of the sensor is switched, the obstacle is detected, so that the safety in transportation can be sufficiently ensured.

[Brief description of drawings]

FIG. 1 is a flowchart illustrating a transportation control method of the present invention.

FIG. 2 is a schematic diagram illustrating sensitivity switching of a sensor.

FIG. 3 is a graph illustrating a change in traveling speed.

FIG. 4 is a schematic diagram illustrating a transport mechanism.

FIG. 5 is a flowchart illustrating a conventional example.

FIG. 6 is a schematic diagram illustrating a conventional example.

[Explanation of symbols]

 1 trolley 2 sensor 3 position detection sensor 11 transport rail 12 wall

Claims (2)

[Claims] 1. In a transport mechanism that travels on a fixed track and is movable within a fixed range, a sensor detects a predetermined detection area on the traveling direction side of the transfer mechanism, and an object in the detection area is detected. Is a transport control method for controlling the traveling speed of the transport mechanism based on the presence or absence of, and if the fixed object existing outside the movable range of the transport mechanism is within the detection range of the sensor, A conveyance control method characterized in that the detection area is narrowed before detecting a fixed object. 2. The conveyance control method according to claim 1, wherein, when the detection area is narrowed, the fixed object is prevented from entering the detection area after being narrowed.