JP2984181B2 - Processing order determination method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a logistics system for a processing step in a hot rolling mill or a steel sheet annealing factory for a steel process, and to a method for controlling material flow in the process.

[0002]

2. Description of the Related Art In hot rolling, the processing order of slabs conveyed from an upper step (continuous casting step or a slab yard placed thereafter), for example, a rolling order, satisfies the rolling restrictions due to the attributes of the preceding and following slabs. Was decided to do so.
This type of processing order is generally determined by the intuition and experience of the operator. Recently, it has been determined by a knowledge engineering application system using the knowledge of operators.

[0003]

In this type of conventional method, the order is determined in consideration of only the attributes (relative position constraints) of two consecutive slabs. However, this method has a problem that it is not possible to satisfy the constraint on the rolling position of the slab (absolute position constraint).

The previously filed Japanese Patent Application No. 05-1010
In No. 05, the rolling order is determined, and then the distribution of the heating furnace is searched to determine the distribution of the rolling order and the charging furnace.

[0005] Further, not only the relative position constraint during rolling, but also
The rolling order is determined by considering the absolute position constraint. However, in this case, the generation of an order solution that satisfies the rolling constraints also involves a method of generating a rolling order by trial and error and checking whether the constraints are satisfied. There was a problem that calculation time was required.

According to the present invention, when determining a rolling order, it is possible to determine an optimal rolling order by a feasible rolling order generation method that takes into account not only relative position constraints in the past rolling but also absolute position constraints. It is an object of the present invention to provide a method for determining a processing order of a hot rolling factory or the like.

[0007]

According to the method of the present invention, a material data input section having a function of inputting an attribute of a material to be processed, an attribute such as a width, etc., for determining a processing order of a slab or the like in a rolling mill. A sorting unit having a function of sorting by, a matrix calculation unit that expresses a constraint condition of a processing order by a matrix,
In a processing order determination method including a rolling order solution search unit that generates an executable processing order and calculates an evaluation function related to the processing order, the absolute order constraint and the relative order constraint expressed in a matrix are expressed in a multi-stage graph. An executable processing order solution is obtained by obtaining an effective path.

[0008]

Next, the present invention will be described with reference to the drawings. The determination of the rolling order in the hot rolling process will be described as an example. FIG. 2 shows the configuration of the hot rolling factory.

A slab placed in a slab storage place 201 or a slab carried by a wagon 202 is placed on a table 203 in front of a heating furnace, and a heating furnace 204 comprising three furnaces.
Will be charged. At this time, the charging slab (cold flakes depending on the temperature,
An appropriate furnace is determined and charged for the heating piece. The slab in the heating furnace is heated by the in-furnace time (time spent in the heating furnace) and the extraction temperature according to the charging slab temperature. The slab that has reached the extraction temperature according to the schedule is extracted from the heating furnace after waiting for a time interval necessary for rolling with the previous extraction slab, and is rolled by the VSB (slab width control rolling mill), the rough rolling mill 206, and the finishing rolling mill 207. The water is cooled by a ROT (cooling table) 208 and wound by a coiler 209. The manufactured coil is in the product storage 2
It is transported to 10.

FIG. 3 shows a hardware configuration of a rolling order determining method used for determining a rolling order of the equipment, and FIG. 1 shows a configuration of processing (software in this example) of the scheduling method.

In this scheduling method, the following first to fifth steps are performed.
The rolling order of about 80 to 150 slabs is determined.

Step 1: In the slab data input section 101, slab attributes are input by file transfer via the keyboard 303, mouse 305 or network 304. Table 1 below shows an example of attribute information.

[0013]

[Table 1]

Step 2: The width sorter 102 sorts the input order of the attribute data of the slab for some attributes. For example, sort in the order of width. The order of the results is used as a slab number used in the subsequent rolling constraint matrix and the like.

Step 3: The rolling constraint matrix calculation unit 103 obtains a rolling constraint matrix for the material slabs sorted in step 2 from the operation rules (rolling constraints) and the slab arrival times. The absolute position constraint matrix A indicates the absolute position constraint on the rolling order (the range of the rolling order is specified for each slab as, for example, the first to eighth), and the relative position indicates the constraint on the relative position of the preceding and following slabs. A relative position constraint matrix R representing constraints (designating that slab 2 can be rolled after slab 1 but slab 3 cannot be rolled) is generated.

[0016]

(Equation 1)

Step 4: The rolling order search section 104 searches for an optimal solution of the rolling order.

First, in the rolling order feasible solution generating unit 105,
Generate a viable rolling sequence.

In the case of N slabs, the decision variable x is as follows.

[0020]

(Equation 2)

This generation method will be described later in detail.

The rolling order evaluation calculation unit 106 evaluates a matrix e indicating the difficulty of rolling two slabs to be continuously rolled.
[I] [j] is generated. For example, under the condition of the following expression (8), an evaluation value matrix of the following expression (9) is obtained.

[0023]

(Equation 3)

The optimum rolling order is selected from those that minimize the evaluation function as shown in the following equations (10) and (11).

[0025]

(Equation 4)

Hereinafter, a specific method of generating an execution solution of a rolling order will be described.

First, the absolute position constraint and the relative position constraint previously expressed in a matrix are represented as shown in FIG. 4 using a multistage graph.

The k-th rollable slab number defined by the absolute position constraint is set to the k-th node, and the continuous rollable slab order determined by the relative position constraint is set to the arc between the nodes included in the adjacent stages. If the evaluation value indicating the difficulty of the above is made to correspond to the weight of the arc, it can be expressed by a multi-stage graph as shown in FIG. At this time, among the paths from the first stage to the Nth stage, those having no node number overlap (valid paths)
And the sum of the weights of the arcs at that time gives an evaluation value of the rolling in the entire rolling sequence. In FIG.
Processing to determine feasible rolling order ~ 5. The procedure will be described.

First, the symbols are defined as follows.

K (t): set of stages whose nodes are not selected S _k (t): set of nodes (numbers) included in the k-th stage C _i (t): set of stages including node i IA _ki : If the node i is selected at the k-th stage, the (k-1) th
A set of nodes (numbers) selectable at the stage (i∈S _k (t); k = 2,..., N) OA _ki : When node i is selected at the k-th stage, the (k + 1) th
A set of nodes (numbers) selectable at the stage (i∈S _k (t); k = 1,..., N−1) O _k : a node (number) selected at the k-th stage, where t is The number of iterations of the calculation (for each iteration,
(A certain node is selected).

0. Set the initial state of the multi-stage graph.

The number of repetitions is set to t = 1. Also K
(1) = {1, 2,..., N}, and S
_k (1) (k∈K (1)) and C _i (1) (i = 1, 2,...,
N), IA _ki (1) and OA _ki (1) (i∈
S _k (1), k∈K (1)).

1. Next, one node is selected from the multi-stage graph. That is, the rolling order of one slab is determined. As one of the methods, from the minimum stage of the number of nodes included in each stage,
Nodes not included in other stages shall be selected.

First,

[0035]

K * = arg min | S _k (t) | (12) From k∈K (t), find the stage with the minimum number of nodes included in each stage.

Next,

[0037]

I * = arg min | C _i (t) | (13) From k∈S _k *, among the nodes included in the stage found above, the node having the minimum number of stages including the node is defined as select.

As a result

[0039]

It is assumed that O _k * = i * (14).

2. Next, in the multi-stage graph, the above 1 .. Remove the nodes belonging to the same stage other than the nodes selected in and the arcs at the nodes. That is, for the k * th stage,

[0041]

S _k * (t + 1) = {i *} (15) The node selected is set.

[0042]

OA _k * ₋₁ , _i (t + 1) = OA _k * ₋₁ , _i (t) − (S _k * (t) − {i *}) (i∈S _k * ₋₁ ( _{t)) (16) IA k} * +1, i (t + 1) = IA k * +1, i (t) - (S k * (t) - {i *}) (i∈S k * + ₁ (t)) Update so that only the arc set related to the node selected by (17) is left.

Further,

[0044]

K (t + 1) = K (t) − {k *} (18) C _i (t + 1) = C _i (t) − {k *} (i∈S _k * (t) − {I *}) (19) According to C _i * (t + 1) = {k *} (20), K (t + 1), C _i (t + 1), C _i * (t + 1) To update.

3. Next, the nodes selected above are removed from the stage where no nodes are selected. That is, each stage k (k∈K (t
+1))

[0046]

S _k (t + 1) = S _k (t) − {i *} (21) S _k (t + 1) = S _k (t) − {i *} (22) For each stage k (k∈K (t + 1)),

[0047]

OA _k * ₋₁ , _i (t + 1) = OA _k * ₋₁ , _i (t) − {i *} (i∈S _k * ₋₁ (t + 1)) (23) IA _{k * +1, i (t +} 1) = IA k * +1, i (t) - {i *} arc set for _{(i∈S k * +1 (t +} 1)) is removed node as (24) Is also removed.

4. Next, 1. From 3. By selecting and removing the nodes of, nodes that are not connected to the previous and subsequent stages are removed. That is, for each stage k (k∈K (t + 1)),
Search for a node that is not connected before or after and remove that information.

[0049]

A node i ′ where IA _k , _{i ′} (t + 1) = 0 or (25) OA _k , _{i ′} (t + 1) = 0 (26) is found,

[0050]

S _k (t + 1) = S _k (t + 1) − {i ′} (27) C _{i ′} (t + 1) = C _{i ′} (t) − {k} (28) OA _k−1 , _i (t + 1) = OA _k−1 , _i (t + 1) − {i ′} (i∈S _k−1 (t + 1)) (29) IA _{k + 1} , _i ( t + 1) = IA _{k + 1} , _i (t + 1) − {i ′} (i∈S _{k + 1} (t + 1)) (30)

This procedure is repeated until there are no more nodes to be removed.

5. Judgment If t = N, end. Otherwise, set t = t + 1 and 1. Return to

When a feasible solution is obtained, a solution having a better evaluation value is searched by a search. For this, a neighborhood search, for example, a method of changing the order of two slabs is used.

Next, a method for generating a search point will be described.

Focusing on certain two contact points i ₁ and i ₂ included in the effective path (feasible rolling sequence) shown in FIG. 5 obtained above, these nodes are

[0056]

P ₂ ｆIA _k1 , _i1 (1) (31) f ₂ ∈OA _k1 , _i1 (1) (32) p ₁ ∈IA _k2 , _i2 (1) (33) f ₁ ∈OA _k2 , _i2 (1) Exchange is possible if all of (34) are satisfied. Equations (31) and (32) show that i ₁ can be connected to p ₂ and f ₂ ,
Equations (33) and (34) show that i ₂ can be connected to p ₁ and f ₁ . That is, the path shown in FIG. 6 is a valid path.

The setting of the exchange pair is performed as follows.

1) Initialization Assume that a set of exchangeable node pairs is C = 0.

2) Extraction of exchangeable contact pairs It is checked whether or not all the node pairs (i ₁ , i ₂ ) included in the effective path satisfy the conditions of the above equations (31) to (34). , Where C = C + ｛(i ₁ ,
i ₂ )｝.

3) Selection of exchange node pair One element (node pair) is selected from the set C, and a path obtained by exchanging these nodes is set as a new effective path (solution candidate).

Step 5: The result output unit 111 outputs the optimal rolling order result obtained as a result.

[0062]

According to the present invention, it is possible to search for the optimum solution of the evaluation value of the processing order by generating the rolling order by the present method in a short time, and it is possible to carry out distribution control for optimizing the rolling order. As a result, it is possible to improve productivity, reduce costs, and stabilize quality.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a processing configuration of a distribution scheduling method in a hot rolling plant.

FIG. 2 is a block diagram showing an actual hot rolling factory.

3 is a block diagram showing an example of hardware for realizing the configuration of FIG. 1 and the operation of FIG. 2;

FIG. 4 is a schematic diagram showing a multi-stage graph expression of a rolling order determination problem.

FIG. 5 is a schematic diagram showing an effective path indicating one feasible solution.

FIG. 6 is a schematic diagram showing an effective path indicating a feasible solution obtained by exchanging two nodes.

FIG. 7 is a flowchart showing a rolling order executable solution generation procedure.

[Explanation of symbols]

101: Slab data input unit 102:
Sorting unit 103: Rolling constraint matrix calculation unit 104:
Rolling order search unit 105: Rolling order executable solution generation unit 106:
Rolling sequence evaluation calculation unit 107: Result output unit 201:
Slab Depot 202: Freight Car 203:
Table 204 before heating furnace: heating furnace 205:
VSB, 206: Rough rolling mill 207:
Finishing mill 208: ROT 209:
Coiler 210: Show product storage
d: slab to be rolled e: coil f: slab, indicates the direction in which the coil moves. 301: Display 302:
Workstation 303: Keyboard 304:
Mouse 305: Hard disk 306:
network

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B21B 37/00

Claims (1)

(57) [Claims] 1. A material data input unit having a function of inputting an attribute of a material to be processed in order to determine a processing order of a slab or the like in a rolling mill, a sort unit having a function of sorting by an attribute such as a width, and a process. In a processing order determination method including a matrix calculation unit that expresses an order constraint condition as a matrix and a rolling order solution search unit that generates an executable processing order and calculates an evaluation function related to the processing order, an absolute order represented by a matrix A processing order determination method characterized by expressing constraints and relative order constraints in a multi-stage graph, and obtaining an executable processing order solution by obtaining an effective path therefrom.