Embodiment
A kind of method of optimizing hot rolling scaduled sequence, realize in two steps: at first being rolling scaduled order adjustment, is the sequencing of least unit plan for adjustment with rolling scaduled, does not relate to the change of the inner material of plan; Carry out rolling scaduled material adjustment then on the basis of rolling scaduled order adjustment, this step is whole to be unit with the slab, only relates to the change of rolling scaduled inside and rolling scaduled 's material.
The overall principle of rolling scaduled sequence optimization is to do limited adjustment on the basis of the rolling scaduled unit of determining, does not do large-scale adjustment.If violate the intermediate solution of process rule, general strategy is abandoned it exactly, and does not do the adjustment at rule in the algorithm search process.Rolling scaduled sequence is optimized process flow diagram as shown in Figure 1.
(1) rolling scaduled order adjustment
Rolling scaduled order adjustment be a complexity be the factorial level (O (n! )) combinatorial optimization problem, can not solve with the method in traversal search space.Find the solution employing simulated annealing, simulated annealing is a kind of intelligent algorithm of comparative maturity, is applicable to the combinatorial optimization problem that the search volume is very big.In order to improve the performance of algorithm, in algorithm, add the data structure of a taboo table, keep several the separating of search recently.
The form of expression of separating of rolling scaduled order adjustment model is a sequence of rolling scaduled number, determines that with rolling scaduled order the corresponding hot charging in back is than weighing the quality of separating.
Model description:
s.t. t
ri≥t
ci+T i∈{1,2,A,n} (3)
The total quantity of n slab wherein;
C
FiThe hot charging of i piece slab than mark (i=1,2 ..., n), 1 is hot charging, 0 is cold charge;
t
RiThe rolling time of i piece slab;
t
CiThe break time of i piece slab;
The T continuous casting is put the time to the biography of hot rolling.
The optimization aim of formula (1), the rolling scaduled order adjustment of formula (2) expression is adjusted hot charging ratio of maximization and the total residence time in the slab storehouse that minimizes all slabs.This is a multiple goal combinatorial optimization problem, and two targets have different priority, judges that in the algorithm operational process quality of feasible solution uses the value of formula (1), formula (2) to come comparison successively.The requirement that the rolling scaduled order adjustment of formula (3) expression must be observed break time and rolling time coupling, the rolling time of slab must be not less than break time and biography is put the time sum.Because it is original rolling scaduled that rolling scaduled order adjustment does not destroy, so need not to consider the technological procedure constraint in the optimizing process.
Solution procedure:
Rolling scaduled order adjustment model is separated a sequence of rolling scaduled number, with rolling scaduled order determine the corresponding hot charging in back than and the slab quality of separating in storehouse total residence time evaluation.
Solution procedure:
1) provides rolling scaduled order initial solution X0, with annealing temperature initial value T0, threshold value Tmin, annealing temperature drop coefficient α, calculate with the corresponding hot charging of X0 than R0 and slab at storehouse total residence time t, set up the empty array T1 of one dimension and show, make optimum solution Xbest=X0 as taboo, annealing temperature T=T0 upgrades the taboo table with T0;
2) 1 X of picked at random in the neighborhood of X0;
3) judge that X whether in T1, if X was relayed to for the 2nd step at T1, if X upgrades T1 with X not in T1, forwards 4 to then);
4) judge the time coupling (formula (3)) of X, if satisfy hot charging that the time coupling requires to calculate X than R and slab in the storehouse total residence time and forward 5 to), directly do not forward 2 to if match);
5) judge whether X is better than X0,, judge whether X is better than Xbest, make Xbest=X and forward 7 to if X is better than Xbest if X is better than X0), directly do not forward 7 to if X is not better than Xbest); If X is not better than X0, forward 6 to);
6) probability of acceptance of computational solution
Generate random number rand ∈ [0,1], if P 〉=rand forwards 7 to), otherwise forward 2 to);
7) make X0=X, R0=R, T=T* α
8) judge whether to reach the algorithm stop condition,, provide Xbest) as finally separating, if not forwarding 2 to if stop.Rolling scaduled order is adjusted flow process as shown in Figure 2.
Illustrate:
Neighbour structure: scope and the relationship between efficiency of separating the neighbour structure setting of X and algorithm search are very big, here neighbour structure is set at arbitrarily selected two set that the rolling scaduled all possible rolling scaduled sequences that its order exchange is formed are formed, and separates that into picked at random two are rolling scaduled to exchange its order for one of picked at random in this neighborhood.
Initial solution: initial solution can adopt heuritic approach to generate, the summation that adds up the break time that each is rolling scaduled, with rolling scaduled according to break time and series arrangement from small to large, as the initial solution of rolling scaduled order adjustment.What also rolling scaduled establishment can be formed is rolling scaduled as initial solution.
The acceptance probability of separating: though the validity of simulated annealing be embodied in algorithm search to feasible solution be inferior to current separating, algorithm will be accepted it according to certain probability and separate as current.This mechanism makes simulated annealing have to jump out the ability of locally optimal solution.Acceptance probability is relevant with annealing temperature with the hot charging ratio of separating in this algorithm, along with this probability of running time of algorithm reduces gradually.
(2) rolling scaduled material order is adjusted
The material adjustment is to carry out under the prerequisite that rolling scaduled order adjustment has been finished, and is that unit adjusts order and position with the slab in rolling scaduled, mainly is rolling scaduled slab position adjustment.Target is to reduce cold and hot base to load in mixture number of times as far as possible, improves the quantity of continuous cold base, Continuous Heat base.
The goal-setting of material adjustment model is the slab number that minimizes continuum number and the maximum continuum of maximization; The constraint condition that will satisfy in the adjustment process is that technological procedure constraint and rolling time---mate break time.
According to the continuum indefinite length, material should allow the characteristics of monolithic slab or whole continuum shift position when adjusting, need to set the adjustment effect that reaches different by different neighborhoods in the search procedure of algorithm.Adopt to become the neighborhood search algorithm, this algorithm is set multiple neighbour structure, is used for the different material of respective material adjustment and moves or the exchange state.
The form of expression of separating of rolling scaduled material adjustment model is carries out adjusted rolling scaduled sequence, the quality of separating is differentiated according to the order of continuum number, maximum continuum slab number relatively, the number of more maximum continuum again under the two situation about all equating.
Adopt three kinds of neighbour structures: single slab inserts, slab exchanges, the continuum exchange.
Model description:
s.t. t
ri≥t
ci+T (6)
Adjacent slab maximum rolling width jump value constraint (7)
Adjacent slab maximum rolling thickness jump value constraint (8)
Adjacent slab highest hardness jump value constraint (9)
The total quantity of n slab wherein;
C
FiThe hot charging of i piece slab than mark (i=1,2 ..., n) 1 is hot charging, 0 is cold charge;
t
RiThe rolling time of i piece slab;
t
CiThe break time of i piece slab;
The T continuous casting is put the time to the biography of hot rolling.
The rolling scaduled number of m
n
ZkMain body material slab number in the rolling scaduled k;
q
jThe mill length of slab j;
w
jThe weight of slab j;
The rolling length constraint of A with the width slab;
BMin
j, BMax
jThe length constraint of rolling slab with surface grade
GMin
j, GMax
jThe length constraint of rolling slab with steel grade
TMin
j, TMax
jThe length constraint of rolling slab with cold and hot base type
LMin
j, LMax
jRolling weight constraints with the slab that flows to
The optimization aim of formula (4), the rolling scaduled material adjustment of formula (5) expression is respectively the adjusted hot charging ratio of maximization and minimizes the total residence time in the slab storehouse of all slabs.This is a combinatorial optimization problem, and two targets have different priority, judges that in the algorithm operational process quality of feasible solution uses the value of formula (4), formula (5) to come comparison successively.The rolling scaduled material adjustment of formula (6) expression also needs to satisfy the coupling of break time and rolling time, and formula (7)-(15) the rolling scaduled material adjustment of expression need be satisfied the constraint of all production technology rules.
Solution procedure
The form of expression of separating of rolling scaduled material adjustment model is rolling scaduled sequence, and the quality differentiation of separating is always compared in the order of the storehouse residence time (formula (5)) than (formula (4)), slab according to hot charging.
Adopt three kinds of neighbour structures: single slab inserts, slab exchanges, the continuum exchange.
Solution procedure
1) initialization procedure: the Nk that determines in the algorithm to use (k=1,2 ..., kmax) plant neighbour structure; Determine initial solution x; Set up historical optimum solution P, upgrade P with x;
2) make k=1, the iterative process of beginning algorithm;
3) 1 x ' of picked at random in the k class neighborhood of x;
4) judge that whether x ' satisfies the rules constraint, does not forward 3 to if do not satisfy), continue execution in step 5 if satisfy);
5) be better than x if satisfy x ', make x=x ' forward 3 then to) with x ' renewal P;
6) judge whether to satisfy k=kmax,, then make k=1, forward 3 to) if k has reached maximal value; If reaching maximal value, k do not forward 7 to);
7) judge whether to satisfy stop condition, stop, export historical optimum solution P, do not make k=k+1 forward 3 to) if do not satisfy if satisfy algorithm.
Rolling scaduled slab is adjusted flow process as shown in Figure 3.
Illustrate:
Neighborhood is set: adopt three kinds of neighbour structures---slab insertion, slab place-exchange and continuum exchange.Wherein the slab insertion is to select a certain block of slab to insert assigned address, and the slab place-exchange is the location swap with the two boards base of appointment, and the continuum exchange is the location swap with two continuums of appointment.
Rules constraint qualification: for the adjusted rolling scaduled rules verification (mostly be most two rolling scaduled) of doing, check the situation that satisfies of rule successively, violate situation and just be judged to be and do not satisfy rule constrain as long as rules occur according to formula (7)-(15).In algorithm is realized in order to improve the operational efficiency of algorithm, the rules check divides two parts to carry out, and retrains the rules (hop limit of rolling width, rolling thickness, rolling hardness, temperature etc.) that must observe between the rolling scaduled middle slab and is carrying out mobile (insertion, exchange, the exchange of polylith slab) preceding testing of slab; Carry out the slab move operation again under the prerequisite of the constraint more than satisfying, carry out other technological procedure checks then.
Upgrade historical optimum solution: after obtaining an intermediate solution in the algorithm, itself and historical optimum solution are made comparisons, keep a more excellent historical optimum solution of conduct.
The sign continuum: judge successively each rolling scaduled in the cold and hot dress state of each slab, the slab of cold charge or hot charging distributes same unique continuum identification number continuously, identifies the sequence number of slab in continuum simultaneously.