JPH02193203A - Method of controlling stop of object on carrying table - Google Patents

Abstract

PURPOSE:To stop an object on a carrying table in a target position in the shortest time with an inexpensive equipment by controlling the stop in accor dance with the slip characteristic different by object. CONSTITUTION:Relations between the speed variation of a carrying table 1 and the extent of slip of a slab 2 are learnt to obtain an optimum speed of the carrying table which is required to stop the slab 2 in the target position in the shortest time. The speed variation of the carrying table 1 for inching control by which the slab is positioned and stopped in the target position is determined by a fuzzy theory when the slab 2 overruns or underruns the target position. Consequently, the slab 2 is positioned in accordance with the difference of slip characteristic due to the shape of the slab 2. Thus, the object like a slab carried on the carrying table is stopped in the target position in the shortest time by the inexpensive equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control method for stopping an object such as a slab conveyed on a conveyance table such as a roller table at a target position in the shortest possible time.

[Prior art]

Conventionally, when stopping a slab or the like transported on a transport table such as a roller table at a target position, passage of the slab is detected using, for example, a light-shielding photo sensor in front of the stopping position. The pulses emitted from the timing trunking and the pulse generator attached to the conveyor table are integrated from that position to the target stop position, the position of the slab is determined, and the speed of the conveyor table is decelerated to stop it at the target position. A method of control is being adopted.

[Problem to be solved by the invention]

However, in this conventional method, the amount of slab slippage that occurs between the conveyance table and the slab cannot be detected, resulting in poor stopping accuracy.In order to prevent slippage, the deceleration rate of the conveyance table is reduced, in other words, the conveyance speed is reduced. However, in this case, the line efficiency will decrease. For this reason, the deceleration rate of the transport table is usually increased,
A method is adopted in which overruns and underruns with respect to the target position due to slab slippage that occur due to this are corrected by inching control of the conveyance table.

However, in this case, equipment such as an image processing system is required to detect the slab position, which increases the equipment cost, and there are also problems such as inching control requiring skill.

The present invention has been made in view of the above circumstances, and its object is to automatically stop an object on a transport table at a target position in the shortest possible time using inexpensive equipment. The purpose of this invention is to provide a stop control method.

[Means to solve the problem]

The object stop control method on a conveyance table according to the present invention is such that in the process of stopping an object conveyed on a conveyance table at a target position, the position of the object is continuously detected optically and the object is conveyed before the target position. Increase or decrease the table speed by repeatedly increasing or decreasing the table speed.

Learn the relationship between the deceleration rate and the amount of slippage of an object, as well as the relationship between the amount of slippage and the time required for inching control of the conveyance table to stop the object at the target position when overrun or underrun occurs with respect to the target position. The optimum deceleration rate to stop the object at the target position in the shortest time is determined, and the increase and deceleration rate of the conveyance table during the inching control are as follows:
Membership functions are determined for critical deceleration rates that vary depending on the shape of the object and determined according to fuzzy logic.

[Effect]

In the present invention, this makes it possible to perform stop control in accordance with the slip characteristics that vary depending on each object.

[Examples] The present invention will be specifically described below based on drawings showing examples thereof.

FIG. 1 is a flowchart showing the control process of the method of the present invention. First, the conveyance table is changed in a predetermined speed pattern, and based on the relationship with the deceleration rate of the conveyance table, the limit deceleration rate of the conveyance table to prevent slipping of the slab and the limit speed determined by this are learned. is made into a table (step Sl).

Normally, when the current slab position is far away from the target stop position, the conveyance table is driven at maximum speed, but when the slab approaches the target position, the target stop position is set, for example, at one point on the conveyor table. When the slab reaches the conveyor table in front of the table, a predetermined speed pattern (see Figure 5)
b)), the conveyance table is repeatedly increased and decreased in a short period of time, and at this time, the speed of the slab is detected, and based on the conveyance table speed VT + slab speed, the slipping characteristics of the slab, specifically, the slippage of the slab is generated. Determine the limit deceleration rate, in other words, the limit speed, of the conveyance table to prevent this from occurring.

Next, based on this learning result, an optimal deceleration rate is determined to stop the slab at the target position in the shortest possible time even if the slab slips on the conveyance table and overruns or underruns occur (step S2). .

In other words, when the slab is transported at a speed exceeding the limit speed,
The time required for the slab to reach the target position and the time required to correct the overrun (or underline, hereinafter the same) that has occurred are determined. In each case, the overrun amount is calculated from the slip characteristics learned in step S1, and the overrun amount is calculated from the table overrun amount, slip characteristics, and slab weight obtained through learning.

Then, based on these, a speed pattern that minimizes the sum of the arrival time and the overrun correction time is determined.

Note that during this optimization calculation, fuzzy logic is applied when selecting weighting coefficients for the speed pattern modification evaluation formula.

The conveying table is driven according to this speed pattern, and the slab is conveyed onto the conveying table after setting the target position.
Deceleration control is performed (step S3).

The overrun of the slab that occurs at that time is corrected by performing inching control on the conveyance table, and the slab is stopped at the target position (step S4).

Stopping at the target position is controlled according to a speed pattern for inching control that has been tabled in advance, and fuzzy logic is applied in this process as well.

A specific configuration for carrying out the method of the present invention will be described below.

FIG. 2 is a schematic side view showing the implementation state of the method for controlling the stop position of an object on a conveyance table according to the present invention, and FIG. 3 is a diagram of the output waveform of the camera. , 3 is, for example, a CCD (ChargeCampl
4 indicates a laser oscillator.

A large number of conveyor tables 1 are installed in series, each of which is driven by an independent drive system. It is assumed that the slab 2 is transported on the transport table 1 in the direction of the arrow and is stopped at a predetermined target position (2). Above each transport table 1 is a camera 3,
Laser oscillators 4 such as Fle-Ne are arranged as a set.

Each camera 3 is arranged above the center of the transport table 1 so as to face vertically downward so that no gap is formed between the fields of view of other adjacent cameras. The laser beam emitted from the laser beam is expanded to approximately the same width as the field of view of the camera 3 through a beam expander, and is projected onto the center of the transport table 1 in the width direction.

Therefore, when the slab 2 is transferred here, an expanded laser beam is projected so as to traverse the slab 2 in the front-rear direction at the center in the width direction, and the reflected light from the beam is captured by the camera 3.

In Fig. 3, the positions of the slab 2 and the conveyance table 1 are plotted on the horizontal axis.
Also, the output of the camera 3 is plotted on the vertical axis, and as is clear from this graph, the output from the slab 2 is much larger than the reflected light from the transport table 1, so the direction of movement of the slab 2 is shown. Front end (top), rear end (
The position of the bottom) will be detected.

FIG. 4 is a block diagram showing the drive control system of the conveyance table 1, and shows the slab 2.0 on which the laser beam is projected. The reflected light from the conveyance table 1 is captured by the camera 3, its output is taken into the camera control section 11, the top and bottom of the slab 2 in the moving direction are detected, and this is output to the position detector 12. The position detector 12 detects the top and bottom positions of the slab 2 based on the input data at a cycle of, for example, 10 msec, and detects the top and bottom positions of the slab 2 at a cycle of, for example, 10 msec, which is then detected by the line tracking control section 13, the optimum speed calculation section 14, the fuzzy control section 15, and the CPU. Output to subtracter 16.

The line tracking control unit 13 determines and drives the transport table that needs to be driven based on the input current position of the slab 2, and also optimizes the drive or stop signal to stop driving unnecessary transport tables 1. It is output to the speed calculation section 14, motor drive system 18, and subtractor 16. Further, the subtracter 16 calculates the difference ΔL between the current slab position input from the position detector 12 and the stop target position Lo input from the line tracking control section 13, and outputs this to the speed command section 17. When the current position of the slab 2 is far from the target stop position, in other words, when ΔL is large, the selector switch SW is turned on, the switch SW2 is turned off, and the speed command unit 17 outputs the motor based on the data input from the subtractor 16. A command signal is output to the drive system 18, and the speed control of the transport table necessary for increasing transport efficiency is performed. On the other hand, when ΔL is below a certain level, that is, when the slab 2 approaches the target stop position and reaches the top of the conveyance table 1 before the target stop position, the switch SW is turned off.
is turned on, the output from the optimum speed calculation unit 14 is input to the speed command unit 17, and the output is sent to the motor drive system 18 in order to increase or decrease the speed of the conveying table 1 for a short time in the speed pattern shown in FIG. 5(A). Output a signal. Optimal speed calculation section 1
4 is the position detector 1 during the increase and deceleration control of the transport table 1.
The positional data of the slab 2 is taken in from 2 and the speed (2) of the slab 2 is determined, and the optimum speed of the conveyance table 1 is determined based on the speed (7) of the conveyance table 1 inputted from the line tracking control section 13.

(Optimum Speed Calculation Process) FIG. The speed ■ is determined, and the difference between the conveying table speed ■7 and the slab speed ■, that is, the sliding speed Δ■ of the slab 2, is determined to learn the sliding characteristics of the slab 2.

AV s −Vt V s FIG. 5 (b) is a graph showing the relationship between the speed change amount Δ■ of the conveying table l and the sliding speed Δ■ of the slab 2,
The horizontal axis represents the speed change amount Δ■ of the conveying table 1, and the vertical axis represents the sliding speed Δ■5 of the slab 2. As is clear from this graph, slipping of slab 2 does not occur when the amount of speed change is between AV1 and AV2, that is, within the limit amount of change (increase/deceleration amount of change), and when it exceeds this, slipping of slab 2 occurs. I understand.

FIG. 6 is a graph showing the content of learning. The relationship between the case of speed increase and the case of deceleration is substantially the same, and the case of deceleration will be specifically explained.

FIG. 6(a) is a graph showing the relationship between the deceleration rate of the conveyance table 1 and the time required for it to stop, and the horizontal axis shows the deceleration rate Δ.
(2) is also shown with time plotted on the vertical axis. As is clear from this graph, the larger the deceleration rate ΔvR, the shorter the time required to stop the vehicle. Figure 6 (b) is a graph showing the relationship between the amount of slippage of the slab and the inching control time for correcting overrun, with the amount of slippage on the horizontal axis;
Also, time is plotted on the vertical axis. fl+f in graph
ffi is a slip characteristic line made into a table, and fo is a characteristic line obtained as a result of learning. This learning is performed as follows. First, from among the slip characteristic lines tabulated based on the slab weight, width size, etc., the value with the smallest slip amount for the relevant slab, that is, the value with the smallest deceleration rate ΔV
The characteristic line f giving 11mX1 is the value with the largest amount of slip,
That is, select the characteristic line f2 that gives the largest deceleration rate ΔV 11aX□, and select the intermediate deceleration rate Δv1□1kuΔ■
, □AV max2, and AV ++mx
−ΔVIIllXl=ΔVI1. X2-AV max
Furthermore, the characteristic line f1. Straight line distance rl+γ to f2
A characteristic line r0 in which 2 is T and -γ2 is obtained.

FIG. 6(c) is a graph that combines the graphs of FIG. 6(a) and FIG. 6(b), and the value Δ■ on the horizontal axis at the intersection of the two. is the optimal deceleration rate that allows slab 2 to reach the target position quickly and also minimizes the inching control time required to correct overrun. Based on this, the optimal speed is determined and this is used as the optimal speed pattern for fuzzy control. section 15 and the speed command setting section 17 . In addition,
In the process of determining this speed pattern, fuzzy logic is used to select distortion coefficients for speed pattern modification evaluation.

(Function of the fuzzy control section) By the way, in the graph of FIG. There is a close relationship with the shape of the slab 2, such as when the slab 2 is flat, curved upward, or curved downward.

Figure 7 (a) is a graph showing the relationship between the speed change amount ΔV of the conveying table and the slippage of the slab 2 when the slab 2 has upward deformation, and Figure 7 (b) is a graph when the slab is flat. The speed change amount Δ■ of the conveying table 1 and the slab 2 at
FIG. 7 (C) is a graph showing the relationship between the sliding speed and the conveying table 1 when the slab 2 has downward deformation.
2 is a graph showing the relationship between the amount of speed change ΔV and the slippage of the slab 2. As is clear from this graph, it can be seen that the slip characteristics change depending on the shape of the slab 2.

Therefore, for example, regarding the flat slab 2 shown in FIG. 7(b), the critical speed change amount Δ■1 of the conveying table 1 at which slippage occurs. Δv2 and the sliding speed of the slab at that time Δ■,
1. Find ΔVS2 and calculate membership coefficient values X, AVIX Av z + in fuzzy logic for these
X av s + +

For example, the membership coefficient value X AV + is set to 0 for upward slope slabs, 0.5 for flat slabs, and 1.0 for downward slope slabs, and the shape of slab 2 is determined. Based on this, a gain is determined to set the speed change rate of the transport table necessary for performing inching control, and is output to the speed command section 17, and the gain is output to the speed command section 17,
8 to determine the speed change rate for inching control of the conveyance table 1.

Further, when the slab 2 stops on the target table, the switch SWz is turned off and the switch SW is turned on, and the above-mentioned output from the fuzzy control section 15 is input to the speed command section 17, and inching control is performed. .

In addition, in the above-mentioned embodiment, the camera 3. Although the configuration in which the laser oscillator 4 is arranged has been explained, the camera 3. The slit-shaped light beam light source may be mounted on a cart that runs along the upper side of the conveyance table, and the cart may be moved as the slab moves to continuously detect the position of the slab.

〔effect〕

As described above, the method of the present invention learns the relationship between the speed change rate of the transport table and the amount of slippage of the object, and determines the optimal speed of the transport table necessary to stop the object at the target position in the shortest possible time. In addition, when an object overruns or underruns the target position, the rate of change in speed of the conveyance table for inching control, which positions and stops the object at the target position, is determined using fuzzy logic. The present invention has excellent effects, such as being able to accurately and quickly position objects according to differences, and requiring less expensive equipment. .

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the control process of the method of the present invention;
Fig. 2 is a schematic side view showing the transport table used in the method of the present invention, Fig. 3 is a waveform diagram showing the camera output in the light sectioning method, and Fig. 4 is a block diagram showing the control system for carrying out the method of the present invention. Figure 5(a) is a graph showing the speed pattern of the conveying table for learning the slipping characteristics, FIG. 5(b) is a graph showing the slipping characteristics of the slab, and FIG. 6(a). (B) and (C) are graphs showing the learning content for determining the optimum speed, and FIG. 7 is a graph showing the relationship between slab shape and slip characteristics. 1... Conveyance table 2... Slab 3... Camera 4... Laser oscillator 11... Camera control unit 12
...Position detector 13...Line tracking system・
Control unit 14...Optimum speed calculation unit 15...Fuzzy control unit 16...Subtractor 17...Speed command unit 18.
...Motor drive system patent Applicant: Sumitomo Metal Industries Co., Ltd. Agent Patent attorney: Noboru Kono 1 PO case

Claims (1)

[Claims] 1. In the process of stopping the object being transported on the transport table at the target position, the position of the object is continuously detected optically and the transport table speed is repeatedly increased/decreased before the target position. The relationship between the increase in deceleration rate and the amount of object slippage, and the relationship between the amount of slippage and the time required for inching control of the conveyance table to stop it at the target position when overrun or underrun occurs with respect to the target position. The optimum deceleration rate for stopping the object at the target position in the shortest time is determined by learning the above-mentioned inching control, and the increase in the number of transport tables and the deceleration rate are calculated using a fuzzy membership function for the limit deceleration rate that varies depending on the shape of the object. A method for controlling the stop of an object on a conveyance table, characterized in that a decision is made according to logic.