JPH03100809A - Collision controller - Google Patents

Abstract

PURPOSE:To perform the control of collision with the use of a simplified device by deciding whether an emergency stop instruction should be produced or not based on the stop distance calculated from the time points when two position marks are read and the distance between two transfer mechanism. CONSTITUTION:The position mark reading means 1 and 2 provided on the transfer mechanisms A and B recognize the present positions of both mechanisms A and B from the read information and hold this position data until the next position is read. Thus the newly read position data on the position marks are updated each time. A distance detection means 3 detects the distance between mechanisms A and B from the position data on both mechanisms A and B. A timer 4 counts the stay time in a section defined by two position marks, and the data on the corresponding relation between the counted stay time and the stop distance is previously stored in a memory 5. A control means gives the emergency stop instructions to both mechanisms A and B when a dangerous state is decided from the position data on the means 3 and the stop distance data read out of the memory 5. Thus, it is possible to perform the highly accurate control of collision with the use of a simple equipment.

Description

TECHNICAL FIELD The present invention relates to a collision control device, and more particularly to a collision control device for two transfer mechanisms for taking out and conveying articles from a storage shelf in which a large number of articles are stored.

Prior Art Conventionally, collision control for this type of transfer mechanism includes a method of making an emergency stop when the distance between two transfer mechanisms becomes within a certain distance, or a means of detecting the speed of each of the two transfer mechanisms. There was a system that would add an emergency stop to the vehicle if it became dangerous depending on the speed and distance.

However, in the distance-based control method, in order to calculate the distance from receiving a stop command until the transfer mechanism actually stops (braking distance), the stopping distance at maximum speed must be taken into account. However, when the moving speed is slow, the disadvantage is that there is a large loss of time.

Furthermore, the control method based on distance and speed has the disadvantage that the speed detection method detects the position W of the transfer mechanism at each set period, which makes the device complicated and the manufacturing cost high.

OBJECTS OF THE INVENTION An object of the present invention was made to compensate for the above-mentioned drawbacks, and it is an object of the present invention to provide a collision control device that can perform highly accurate control with a simple device.

Composition of the Invention The collision control device of the present invention is a collision control device for two transport mechanisms that reciprocate independently on the same path, and includes a plurality of position markers provided at equal intervals on the path; Position mark reading means provided in each of the two transport mechanisms to read the position mark, and each of the position mark reading means measuring each time from reading one position mark to reading another position mark. a memory that stores in advance the correspondence between the stopping distance from when the transfer mechanism receives braking until it stops and the measurement result of the measurement means; and a memory that stores in advance the correspondence between the stop distance from when the transfer mechanism is braked until it stops and the measurement result of the measurement means; The present invention is characterized in that it includes a distance detecting means for detecting a distance between the transport mechanisms, and a means for controlling generation of an emergency stop command for the transport mechanism using the stop distance and the distance between the transport mechanisms.

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

First, referring to FIG. 2, FIG. 2 is a plan view of a magnetic tape storage shelf in which the collision control device of the present invention can be installed. Two transfer mechanisms A and B for this purpose and a pair of rails 9a and 9b, which serve as movement paths for these transfer mechanisms A and B, are required as peripheral equipment.

FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, a collision control device according to an embodiment of the present invention includes position reading means 1 and 2 provided in transfer mechanisms A and B, respectively.
The distance detection means 3 detects the distance between the two transport mechanisms A and B from the position data read by the position reading means 1.2, and is set and reset in conjunction with the position reading means 1.2, respectively. A possible timer 4, a memory 5 that stores in advance the correspondence between the time measured by the timer 4 and the stopping distance, and distance data from the distance detection means 3 and stopping distance data from the memory 5 are used to determine whether it is dangerous or safe. A control means 6 that issues an emergency stop command if it is determined to be dangerous, and position markers 11, 12, . ...20.

In such a configuration, the position mark reading means 1 is connected to the transport mechanism A.
The position mark reading means 2 is provided in the transport mechanism B. The position mark reading means 1.2 that has read the position mark recognizes the current position of each of the transport mechanisms A and B from the read information, holds this position data until reading the next position, and stores the position data at the newly read position. The position data of the sign shall be updated each time.

The distance detecting means 3 detects the distance between the two transport mechanisms from the position data of the transport mechanisms A and B.

The timer 4 measures the time from the time one of the position mark reading means 1.2 reads one position mark to the time when the other position mark is read.
When one position marker is read, it is necessary to stop the timer currently measuring and simultaneously start a new measurement, and the other reading means also measures time in the same manner as above. In other words, the total stay time in the section made up of the two location markers is 1111.
It is something to do.

Suppose that the position mark reading means 1 reads the position mark Pn at time 11, and the position mark Pn'(n' is n+1 or n-1
) was read at time [2, and if the distance between the two position markers is g, then the time Δt('-t2-t
1), the transport mechanism A has moved by a distance p, and in this case, the velocity vA of the transport mechanism A at the position mark Pn'' is roughly estimated by g/Δt. The speed determined is updated every time the position marker is read, and the latest speed is always recognized.

As a special case, if the vehicle stops, makes a U-turn in the direction it came from, and reads the position marker Pk again after reading the position marker Pk, the speed will not be calculated because the data is sufficient and the speed cannot be calculated.

The velocity calculation for the transfer mechanism B is performed in the same manner.

If we set all the position markers at equal intervals,
The speed depends only on the measured time, and in the example above v
A is proportional to 1/Δt.

The stopping distance detection means 5 calculates the speed from the time measured by the timer 4, and furthermore, the stopping distance is the distance traveled at that speed until it stops upon receiving an emergency stop command. It also includes a distance set in advance to prevent sudden shocks from being applied to items stored in the storage area.

This stopping distance is proportional to speed, and since speed is inversely proportional to time, stopping distance is inversely proportional to time.

If the correspondence between this time and the stopping distance is determined in advance, the stopping distance can be directly determined from the time measured by the timer 4. Therefore, it is assumed that data indicating this relationship is stored in the memory 5 in advance.

The control means issues an emergency stop command to the transfer mechanisms A and B when it is determined that there is a danger based on the position data of the distance detection means 3 and the stopping distance data read from the memory 5.

Location markers 11, 12. ..., 19 is the transfer mechanism A.

It is provided on the movement path of B, and has a structure that allows it to be distinguished from each other so that it can be determined whether the movement is to the right, left, or U-turn.

FIG. 3 is a graph showing the relationship between the position mark and the position data read by the position mark reading means, where the horizontal axis shows the physical position and the vertical axis shows the position read by the reading means. In the figure, position markers are placed at equal intervals on the movement path of the transfer mechanism.
There are several.

The transport mechanism holds the position data of the read position mark until the next position mark is read.

FIG. 4 is a flowchart showing the operation of one embodiment of the collision control device of the present invention. In this embodiment, a case is assumed in which a position marker is provided that allows position data to be read at any point on the movement path of the transport mechanism.

When the program is started, the position data is read by the step knob 21. In step 21, the currently read position data is compared with the previously held position data, and if it has changed, the process goes to step 23, and if it has not changed, the position data is read again. In step 23,
Stop the timer when the position data changes. Next, the time on the timer is read (step 24) and this time is converted to speed as described above (step 25).

Then, the speed is converted into a stopping distance (step 26), but in the present invention, as described above, the time is directly read from the memory 5 and the stopping distance is directly calculated. Then, it is analyzed whether it is safe or dangerous based on the positions of both transfer mechanisms, that is, the distance between them and the stopping distance (step 27).

Next, if it is determined that it is dangerous based on the analysis result in step 27, an emergency stop command is issued, and if it is determined that it is not dangerous, the timer is reset or reset (step 2).
8.29.31). Immediately after the timer is reset, it is started again (step 30) and the process returns to step 21.

Figure 5 shows typical cases when performing risk analysis. Figure 5 (a) shows both moving inward, Figure 5 (b) shows one moving outward and the other moving towards the inside. It is assumed that the object is moving inward as if chasing it.

In FIG. 5(a), the transport mechanism A moves at a speed v from left to right.
A, the transport mechanism B is moving from right to left with speed vB. Here, the stopping distance S^ is the distance that the transport mechanism A, which is moving at the speed V^, will move until it stops when an emergency stop command is given, and SB is the distance that the transport mechanism B, which is moving at the speed vB, will move. This is the distance the vehicle will travel before it stops if an emergency stop command is given to the vehicle. d is the distance between the two transfer mechanisms when stopped by an emergency stop command, and it is necessary to provide a certain margin, and this margin is shown.

Here, if d-0, it means that the two are in contact, and if d<O, it means a collision.

Therefore, when it comes to collision control, there is a certain distance of 11! ld
is given as a margin, and this distance d must be determined in advance by experiment.

In FIG. 5(b), the transfer mechanism A moves to the left at a speed vA
Assume that the transport mechanism B is also moving to the left at a speed vR, and the stopping distance is 5 ASSO.

Assuming that the distance between the two pillar feeding mechanisms is D, in the case of FIG. 5(a), if D=SA +SB + r, it is judged to be dangerous. In addition, in the case of FIG. 5(b), D-8I3-SA+r
If so, it is considered dangerous.

Although a data table is used to convert the time measured by a timer into a stopping distance, more detailed control can be achieved by increasing the number of position markers.

Effects of the Invention The collision control device of the present invention calculates the stopping distance from the time when two position markers are read, that is, the speed, and calculates the stopping distance from the
It is determined whether or not to issue an emergency stop command based on the distance between the two transfer mechanisms, and collision control can be performed with simplified equipment without requiring a complicated device.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the collision control device of the present invention, Fig. 2 is a system configuration diagram including a transfer mechanism that enables the installation of the collision control device of the present invention, and Fig. 3 is a block diagram showing a position marker and 4 is a flowchart showing the operation of the collision control device of the present invention, and FIG. 5 is a block diagram showing an embodiment when the emergency command generating means performs a danger analysis. It is. Explanation of symbols of main parts 1.2...Position mark reading means 3...Distance detection means 4...Timer 5...Memory 6... ...Control means 1'1 to 20...Position indicators A, B...Transfer mechanism

Claims (1)

[Claims] (1) A collision control device for two transfer mechanisms that reciprocate independently on the same path, the device including a plurality of position markers provided at equal intervals on the path, and a collision control device provided for each of the two transfer mechanisms. a position mark reading means for reading the position mark; a measuring means for measuring each time from when each of the position mark reading means reads one position mark until it reads another position mark; and a transport mechanism. a memory that stores in advance the correspondence between a stopping distance from when braking is applied to a stop and a measurement result of the measuring means; and a distance detecting means that detects the distance between the two transport mechanisms based on the reading result of the position mark reading means. and means for controlling generation of an emergency stop command to the transfer mechanism using the stop distance and the distance between the transfer mechanisms.