Speed ​​setting method and system for aluminum strip roughing mill based on multi-objective programming

Abstract

The present invention discloses a speed setting method and system for an aluminum plate and strip rough rolling mill based on multi-objective programming, which relates to the field of control engineering technology, including constructing a multi-objective function by calculating parameters, bite conditions, stable rolling conditions, support roller oil film bearing thickness, and pass ejection speed during the rolling process, and constructing a constraint function based on the multi-objective function through the final rolling temperature, surface quality, and total rolling time, and performing optimal speed calculation based on the constraint function, and correcting the rolling speed in real time to the rolling speed within the pass. The method of the present invention constructs a multi-objective function, and the speed determination not only depends on experience or static models, but also improves the accuracy of parameter setting, constructs a constraint function, pursues speed optimization, performs optimal speed calculation, corrects the rolling speed in real time to the rolling speed within the pass, and finds the rolling speed with the highest production efficiency under the constraint conditions, and the real-time correction adapts to any changes that may occur during the rolling process.

Description

Technical Field

[0001] The present invention relates to the field of control engineering technology, and in particular to a speed setting method and system for an aluminum plate and strip roughing mill based on multi-objective planning. Background Art

[0002] In the production process of aluminum strip rough rolling mill, speed setting is a key link, which directly affects production efficiency, product quality and production cost. Traditional speed setting methods often use empirical formulas or simple models to determine, but with the continuous improvement of market requirements for aluminum strip product quality and production efficiency, these traditional methods can no longer fully meet the needs of modern production; in recent years, with the development of automation and information technology, control systems can monitor and adjust rolling parameters in real time to adapt to various changes in the production process; however, even modern control systems face challenges such as insufficient adaptability to complex process conditions, high cost, low efficiency and poor consistency.

[0003] The prior art has several major deficiencies in the speed setting method of the aluminum plate and strip rough rolling mill. The first is low efficiency. Since the rolling speed setting is not accurate enough, multiple adjustments are often required, resulting in low production efficiency. Secondly, the cost is high. The traditional rolling speed setting method usually cannot take into account both production efficiency and product quality, resulting in waste of resources. In addition, low reliability and low consistency are also important problems of the prior art. Due to the lack of effective feedback on the dynamics of the rolling process, it is difficult to ensure the consistency of product quality in terms of accuracy. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is: the existing speed setting method of the aluminum plate and strip roughing mill has the problems of low efficiency, high cost, low reliability, low consistency, low accuracy, and how to correct the speed of the aluminum plate and strip roughing mill in real time.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a speed setting method for an aluminum plate and strip rough rolling mill based on multi-objective planning, comprising constructing a multi-objective function by calculating the parameters in the rolling process, biting conditions, stable rolling conditions, support roller oil film bearing thickness and pass ejection speed; based on the multi-objective function, a constraint function is constructed through the final rolling temperature, surface quality and total rolling time; based on the constraint function, the optimal speed calculation is performed, and the rolling speed and the rolling speed within the pass are corrected in real time.

[0007] As a preferred solution of the speed setting method of the aluminum plate and strip rough rolling mill based on multi-objective programming described in the present invention, wherein: the construction of the multi-objective function includes calculating the parameters in the rolling process. In the rolling process, based on the influence of the rolling lubricant, the friction coefficient between the rolled piece and the roller is obtained by a table lookup method, and the critical value algorithm of the rolling speed is obtained by reverse calculation through the calculation of the friction coefficient. When the aluminum plate is hot rolled, the friction coefficient is calculated and expressed as:

[0008] f=λ n ·λ v ·λ c ·λ s ·λ l ·λ r (0.84-0.0004t)

[0009] Where f is the friction coefficient, λ n is the influence coefficient of the roll material, λ v is the influence coefficient of the roller speed, λ c is the influence coefficient of chemical elements in the rolled product, λ s is the influence coefficient of the roughness ratio of the workpiece surface and the roller surface, λ l is the influence coefficient of the aspect ratio of the deformation zone, λ r is the influence coefficient of emulsion composition, and t is the temperature of the rolled piece.

[0010] As a preferred solution of the speed setting method of the aluminum strip roughing mill based on multi-objective programming described in the present invention, the construction of the multi-objective function also includes analyzing and calculating the biting conditions and stable rolling conditions in the rolling process, and calculating the friction coefficient in the biting stage and the friction coefficient in the stable rolling stage based on the critical conditions of the biting stage and the stable rolling stage, which are expressed as:

[0011] f y =tanα y

[0012]

[0013] Among them, f y is the critical value of the friction coefficient between the roll and the workpiece during biting, α y is the bite angle, f w is the critical value of the friction coefficient between the roll and the workpiece during stable rolling, α w K is the contact angle in the stable rolling stage. x is the regression coefficient of the formula.

[0014] Based on the friction coefficient in the biting stage and the friction coefficient in the stable rolling stage, the friction coefficient is calculated, the tangent value of the biting angle is calculated, and the critical condition of biting is obtained, which is expressed as:

[0015]

[0016] in, is the influence coefficient of the roll speed during biting, R is the roll diameter, H is the pass entrance thickness, h is the pass exit thickness, λ s1 is the contact surface morphology coefficient of the workpiece head, and t1 is the temperature of the workpiece head.

[0017] Will Arrange it and express it as:

[0018]

[0019] The coefficient of stable rolling based on the roll speed factor is expressed as:

[0020]

[0021] in, is the influence coefficient of the roll speed during stable rolling, t2 is the temperature of the workpiece excluding the head of the workpiece, and λ s2 It is the contact surface morphology coefficient of the rolled piece excluding the head of the rolled piece.

[0022] based on and Obtained from empirical data tables and The maximum critical speed based on the bite phase is obtained by linear interpolation. Obtain the maximum critical speed based on the stable rolling stage

[0023] As a preferred scheme of the speed setting method of the aluminum plate and strip rough rolling mill based on multi-objective planning described in the present invention, wherein: the construction of the multi-objective function also includes calculating the oil film bearing thickness of the support roller and the pass ejection speed during the rolling process, and the calculation of the oil film bearing thickness of the support roller and the pass ejection speed during the rolling process includes that at the same rolling force, the rolling speed is proportional to the oil film thickness, and at the same rolling speed, the rolling force is inversely proportional to the oil film thickness.

[0024] Calculation of critical minimum film thickness of hydrodynamic lubrication The hydrodynamic lubrication in the oil film bearing of the rolling mill support roll is regarded as full fluid lubrication. Based on the normal load, the contact between the solids is an ellipse. In full fluid lubrication, the minimum oil film thickness is calculated as:

[0025]

[0026] h min =3.63U 0.68 G 0.49 W -0.73 (1-e-0.68kl )

[0027] Among them, R x is the effective radius in the x direction, R y is the effective radius in the y direction, kl is the ellipticity of the contact area, h min is the minimum oil film thickness, U is the velocity parameter in the dimensionless parameters, G is the material parameter in the dimensionless parameters, and W is the load parameter in the dimensionless parameters.

[0028] The calculation of the critical minimum rolling speed for hydrodynamic lubrication includes calculating the critical minimum rolling speed for maintaining the minimum oil film thickness for hydrodynamic lubrication.

[0029] Calculate the oil film thickness h by Reynolds equation f , expressed as:

[0030]

[0031] Among them, X is the Sommerfeld variable, δ is the diameter gap difference between the bearing and the roll neck, and a1 and b1 are constants.

[0032] By back-calculating, the relationship between rolling speed and minimum oil film thickness is obtained, which is expressed as:

[0033]

[0034] in, is the critical minimum rolling speed for minimum oil film thickness, P is the rolling force, γ is the oil viscosity, δ is the diameter gap difference between the bearing and the roll neck, and c1 is a constant.

[0035] Obtain the critical minimum rolling speed for establishing the minimum oil film thickness

[0036] The speed changes of the rolls and the workpiece during the rolling interval are quantitatively calculated. When aluminum is cast, the speed is v1, v ths =v thr =v1,v ths is the ejection speed of the rolled piece, v thr is the speed of the roller when casting aluminum, and the time for the roller and the workpiece to drop from v1 to zero is t r1 ,t s1 The time for the roll and the workpiece to accelerate from rest to maximum speed is t r2 ,t s2 The deceleration and acceleration of the roller and the rolled piece are q1 and q2, the mass of the rolled piece is m, and the aluminum throwing distance is S. s The maximum distance the roller turns is S r The friction force on the roller is F m , the acceleration of the roller is a s, the sliding friction coefficient between the roller and the workpiece is μz. During the entire intermittent process, the friction coefficient μ remains unchanged, and the acceleration of the workpiece is expressed as:

[0037]

[0038] Where g is the acceleration due to gravity.

[0039] When leaving the rolling mill, all the motion states of the workpiece and the rolls are expressed as:

[0040] S s =0.5a s t s1 2

[0041] t s1 =v1 / a s

[0042] S r =0.5q1t r1 2

[0043] t r1 =v1 / q1

[0044] When the rolling mill is not reached, there are four situations. The first situation includes when the workpiece bites into the rolling mill and the roller reaches the maximum speed of the limiting condition, which is expressed as:

[0045] t r1 +t r2 =t s1 +t s2

[0046] S s =0.5a s t s2 2

[0047] t s2 =v bis / a s

[0048] S r =0.5q2t r2 2

[0049] t r2 =v bir / q2

[0050] get

[0051] Based on the first case, the second case includes when the workpiece bites into the rolling mill and the roll reaches the minimum speed of the oil film thickness condition,

[0052] The third case includes when the workpiece does not bite into the rolling mill and the roller reaches the maximum speed of the bite condition, the roller rotates at a constant speed at the maximum speed until the workpiece bites into the rolling mill, and the roller uniform speed time is t r3 , the uniform speed time of the rolled piece is t s3 , and t r1 +t r2 +t r3 =t s1 +t s2 +t s3 , the roller situation is expressed as:

[0053]

[0054]

[0055] For rolled products, When , the rolled piece is in a state of stress and acceleration, which can be expressed as:

[0056] S s =0.5a s t s2 2

[0057]

[0058] when When the rolled piece is accelerated to the maximum and moves at a uniform speed with the roller, it can be expressed as:

[0059]

[0060]

[0061] The third case, satisfying

[0062] The fourth situation includes when the workpiece bites into the rolling mill and the speed of the roll is between the maximum speed and the minimum speed of the limiting condition, based on the calculation not involving the critical value, no calculation is performed.

[0063] In the second case, the rolled piece moves at a uniform speed, t s1 =t s2 , v bis =v1, and the whole intermittent time is calculated by the rolled piece, which is expressed as:

[0064]

[0065] Among them, t inter Rolling interval time.

[0066] During the intermittent time, the roller speed drops to zero and increases to the minimum speed. The intermittent time calculated by the roller is expressed as:

[0067]

[0068] The minimum aluminum casting speed in the horizontal direction is obtained, which is expressed as:

[0069]

[0070] Among them, v x It is the minimum aluminum casting speed determined by the horizontal direction.

[0071] Based on the minimum aluminum throwing speed and the friction coefficient between the roller and the rolled piece, the minimum aluminum throwing distance is expressed as:

[0072]

[0073] The rolling interval time is greater than the swing roll gap time t of the pressing motor vert , based on the intermittent time calculated by the roller, the minimum aluminum casting speed in the vertical direction is obtained, which is expressed as:

[0074]

[0075] Among them, t vert is the swing roller gap time of the pressing motor, v y It is the minimum aluminum casting speed determined by the vertical direction.

[0076] The minimum aluminum casting speed is v x and v y The minimum value in It is the minimum aluminum casting speed.

[0077] The maximum critical value of aluminum casting speed is consistent with the maximum speed during stable rolling. It is the maximum aluminum casting speed.

[0078] As a preferred solution of the speed setting method of the aluminum plate and strip rough rolling mill based on multi-objective planning described in the present invention, wherein: the construction of the constraint function includes constructing the constraint function based on the multi-objective function through the final rolling temperature, surface quality and total rolling time.

[0079] Based on the goal of good final rolling temperature and the highest generation efficiency, mathematical modeling includes determining the first objective function, using rolling speed and rolling time as control variables to construct the final rolling temperature objective function. When the aluminum plate is rolled and the head and tail, material and centering passes are heavy, no optimization is performed. When the aluminum plate is rolled and the ordinary rolling passes are performed, the number of passes of the vertical roller mill is n1, the number of ordinary passes is n, and the bite speed in the jth pass is (v bite ) j , the stable rolling speed is (v sta ) j , the duration is (t sta ) j , aluminum casting speed is (v thr ) j During rolling, the acceleration of the roller is i1, the deceleration is i2, and the acceleration time is (t ac1 ) j , deceleration time is (t de1 ) j , the final rolling temperature limited by the process is T set , the allowable error of the final rolling temperature is ε T The waiting temperature for the final rolling temperature is T ctrl , the pass exit length of the rolled piece is (L s ) j The length of the roller rotation is (L r ) j , the reduction of the roll in the jth pass is (Δh) j , the no-load acceleration of the roller during the intermittent pass is i3, the no-load deceleration of the roller during the intermittent pass is i4, and the acceleration time of the roller during the intermittent pass is (t ac2 ) j , the deceleration time of the roller during the inter-pass interval is (t de2 ) j , the total time of the vertical roller hemming pass is t edge , rated acceleration when loaded is Rated deceleration is The rated acceleration when no load is Rated deceleration is

[0080] During the rolling process, due to the influence of forward slip, the length of the roll surface rotation is less than the exit length of the rolled piece, which can be expressed as:

[0081]

[0082] Among them, L r S is the length of the roll surface during rolling. h is the forward slip value, L s is the length of the rolled piece, and Δh is the reduction per pass.

[0083] Calculate the total rolling time, expressed as:

[0084]

[0085] Among them, t all is the total rolling time, t roll is the rolling time, t z is the pass interval time adjustment coefficient, t de1 is the deceleration time of the roller during rolling, t sta is the stable rolling time, t ac1 is the acceleration time of the roll during rolling, t de1 is the deceleration time of the roller during rolling, t ac2 is the no-load acceleration time, t de2 It is the no-load deceleration time.

[0086] The total rolling time includes the total pure rolling time ∑t roll and the total rolling interval time ∑t inter The total pure rolling time includes the roll acceleration time, deceleration time and constant speed time of j passes. The total rolling time is expressed as:

[0087]

[0088] Among them, v sta To stabilize the rolling speed, v bite is the bite speed.

[0089] When the rolling speed is within the critical value range, the temperature of the rolled piece does not meet (T set -ε T )≤T end ≤(T set +ε T ), the iteration operation ends, T end is the final rolling temperature. When all effective solutions or weak effective solutions of the objective function are infeasible solutions, t z Adjust the static waiting time when the rolled piece is at the maximum aluminum throwing distance, and the initial value is 0.

[0090] The heat radiation and convection of the rolled piece run through the entire rolling stage. The temperature drop function of the rolled piece corresponding to the heat radiation and convection is expressed as:

[0091] T emi =f(t all )

[0092] Among them, T emi is the temperature drop function of the rolled piece corresponding to thermal radiation and convection, f(t all ) is the functional formula of the temperature drop of the rolled piece corresponding to thermal radiation and convection.

[0093] The temperature drop of emulsion spray is T emul , the temperature rise caused by plastic work and deformation heat is T def The time of heat conduction in contact with the roller is t roll The temperature drop function of the rolled piece due to roller contact heat conduction is T con =f(t roll ), T con is the temperature drop function of the workpiece due to the heat conduction in contact with the rollers, f(t roll ) is the functional formula of the temperature drop of the rolled piece due to the contact heat conduction of the rollers.

[0094] Construct the main objective function F(v bite ,v thr ,v sta ), expressed as:

[0095] F(v bite ,v thr ,v sta )=T ctrl -T emi -T emul -T con +T def =T ctrl -f(t all )-T emul -f(t roll )+T def

[0096] When the iteration satisfies |F(v bite ,v thr ,v sta )-T set |≤ε T The iteration stops when the main objective function F(v bite ,v thr ,v sta ) has no solution, t z =t z ±α z , α z The minimum total rolling time is obtained by searching the step length, and the secondary objective function G(v bite ,v thr ,v sta ), expressed as:

[0097] G(v bite ,v thr ,v sta ) = t all

[0098] The main objective function determined by the final rolling temperature is transformed into an auxiliary constraint condition for constructing the secondary objective function determined by the final rolling temperature, and all the constraints are combined. The mathematical model of the optimization problem is expressed as follows:

[0099] min G((v bite ) j ,(v thr ) j ,(v sta ) j )

[0100] St|F((v bite ) j ,(v thr ) j ,(v sta ) j )-T set |≤ε T

[0101]

[0102]

[0103]

[0104] (v sta ) j -(v bite ) j +i1·(t ac1 ) j =0

[0105] (v sta ) j -(v thr ) j +i2·(t de1 ) j =0

[0106] (v bite ) j -i3·(t ac2 ) j =0

[0107] (v thr ) j -i4·(t de2 ) j =0

[0108]

[0109]

[0110]

[0111]

[0112] Among them, G((v bite ) j ,(v thr ) j ,(v sta ) j ) is the main objective function determined by the final rolling temperature at the jth pass, F((v bite ) j ,(v thr ) j ,(v sta ) j ) is the secondary objective function determined by the minimum total rolling time of the jth pass, St is the constraint symbol, is the critical minimum rolling speed to maintain the minimum oil film thickness in the jth pass, is the maximum speed of the j-th bite, is the maximum stable rolling speed of the jth pass.

[0113] As a preferred solution of the speed setting method of the aluminum plate and strip roughing mill based on multi-objective programming described in the present invention, wherein: the speed optimal calculation includes converting the multi-objective problem into an optimization problem of an objective function based on the constraint function, and based on the nonlinear factors of the objective function, and the constraint conditions include equality constraints and inequality constraints, the augmented multiplier method in the constrained nonlinear optimization algorithm is used for calculation, and 12n inequalities and 4n equality constraints are converted into g e (v)≥0(e=1,2,...,12n) and h l (v)=0(l=1,2,3,4n), g e (v) is the inequality constraint function, e is the number of inequality constraints, h l (v) is the equality constraint function, l is the number of equality constraints, and the augmented Lagrangian function is calculated as:

[0114]

[0115] μ=(μ1,...,μ 4n ) T

[0116] λ=(λ1,...,λ 12n )

[0117] in, is the augmented Lagrangian function, G(v) is the objective function, σ is the penalty coefficient, which is greater than 0, and λ eis the Lagrange multiplier associated with the e-th inequality constraint, λ is a vector including the Lagrange multipliers associated with the equality constraint, μ is a vector including the Lagrange multipliers associated with the inequality constraint, μ l is the Lagrange multiplier associated with l equality constraints, and T is the mathematical symbol for the horizontal row of column vectors.

[0118] By modifying the multiplier λ in the kth iteration (k) and μ (k) , get the multiplier λ in the k+1th iteration (k+1) and μ (k+1) , the revised form is:

[0119]

[0120]

[0121] in, is the k+1th iteration of the algorithm, and the inequality g e (v) Updated value of the associated Lagrange multiplier, g e (v (k) ) is the value of the equation constraint in the kth iteration, h e (v (k) ) is the value of the inequality constraint in the kth iteration, is the Lagrange multiplier associated with the l equality constraints.

[0122] The iteration termination criterion is expressed as:

[0123]

[0124] Among them, δ (k) is a measure to evaluate the degree of constraint violation at the kth iteration, h l 2 (v (k) ) is the equality constraint h at the kth iteration. l The value of μ e (k) is the inequality constraint g at the kth iteration. e (v) The value of the associated penalty multiplier, ε is the maximum allowable error value for violating the constraint during iteration.

[0125] The calculation process includes initialization, which includes giving an initial point, expressed as:

[0126]

[0127] Among them, v (0) is the initial vector for iterative velocity calculation, The initial values ​​of the biting speed, ejection speed and stable rolling speed of the jth pass are set to the critical minimum rolling speed for maintaining the minimum oil film thickness.

[0128] Initial estimate of the multiplier vector μ = λ = (1,...,1) T , σ=2, error ε>0, constant θ>1, θ is the step size parameter used to adjust the iterative convergence speed, To adjust the optimization parameter for iterative convergence speed, k=1.

[0129] Solve for v (k) , including v (k-1) As the initial point, solve the unconstrained problem Get the solution v (k) .

[0130] Calculate δ (k) , when the iteration termination criteria are met, stop the calculation and obtain the solution v (k) .

[0131] When the iterative termination criteria are not met, the convergence speed is judged. When σ=θσ, we can calculate and Set k = k + 1 and solve v again (k) , when not satisfied When and Set k = k + 1 and solve v again (k) .

[0132] As a preferred solution of the speed setting method of the aluminum plate and strip rough rolling mill based on multi-objective planning described in the present invention, the real-time correction of the rolling speed and the rolling speed within the pass includes arranging an aluminum plate and strip surface detector after the rolling mill, monitoring the quality of the strip surface in real time, and correcting the preset parameters of the rolling mill speed in real time based on the feedback results of the strip surface detector online, setting the speed curves of all passes in the rolling process, and correcting the stable rolling speed of the remaining passes in real time based on the strip surface quality. The aluminum biting speed and the aluminum throwing speed will change, and the speed will be reduced and adjusted. The final rolling temperature is lower than the final rolling temperature before adjustment.

[0133] When the surface quality is an influencing factor or the final rolling temperature does not change based on the speed adjustment, the speed is reduced. When the surface quality is not an influencing factor, the speed is not reduced and changes are made based on product performance requirements.

[0134] The speed reduction includes that when the surface detector finds defects in the plate at the jth pass, when rolling at low speed and high speed, the speed of the remaining (nj) passes is reduced, and the adjustment step length of the stable rolling speed is β. The adjusted stable rolling speed is expressed as:

[0135] (v sta ′) j+1 =(v sta ) j+1 (1-β)

[0136] Among them, (v sta ′) j+1 is the j+1th pass, the adjusted stable rolling speed, (v sta ) j+1 is the stable rolling speed of the j+1th pass without adjustment.

[0137] When the rolling mill executes the adjusted rolling speed in the j+1 pass, the surface detector detects that the surface quality is unqualified, and the pass continues to be executed, which is expressed as:

[0138] (v sta ′) j+2 =(v sta ) j+2 (1-β)

[0139] Among them, (v sta ′) j+2 is the j+2th pass, the adjusted stable rolling speed, (v sta ) j+2 is the stable rolling speed without adjustment in the j+2th pass.

[0140] Based on the principle that the length of the roller surface rotated by the roller before and after adjustment should be consistent, the area of ​​the two parts will be equal S abcdef =S a′b′c′d′e′f =L r , S abcdef is the area of ​​the hexagon abcdef, S a′b′c′d′e′f is the area of ​​the hexagon a′b′c′d′e′f. After integrating the area value, it is expressed as:

[0141]

[0142] Among them, a is the bite time point before the rolling speed correction of this pass, f c is the ejection time point before the rolling speed correction of this pass, a′ is the bite time point after the rolling speed correction of this pass, and f c ′ is the ejection time point after the rolling speed of this pass is corrected, v(t) is the speed curve before the rolling speed of this pass is corrected, and v′(t) is the speed curve before the rolling speed of this pass is corrected.

[0143] Expand the integral and it can be expressed as:

[0144]

[0145] Among them, v sta ′ is the corrected stable rolling speed, v bite ′ is the corrected bite speed, t ac1 is the roll acceleration time during the corrected rolling process, v thr ′ is the corrected aluminum casting speed, t de1 ' is the deceleration time for correction.

[0146] The speed correction calculation for (nj) passes is expressed as:

[0147] min G((v bite ′) p ,(v thr ′) p ,(v sta ′) p )

[0148]

[0149]

[0150]

[0151]

[0152] (v sta ′) p -(v bite ′) p +i1·(t ac1 ′) p =0

[0153] (v sta ′) p -(v thr ′) p +i2·(t de1 ′) p =0

[0154] (v bite ′) p -i3·(t ac2 ′) p =0

[0155] (v thr ′) p -i4·(t de2 ′) p =0

[0156]

[0157]

[0158]

[0159]

[0160] Among them, G((v bite ′) p ,(v thr ′) p ,(v sta ′) p ) is the main objective function of the pth pass, which is determined by the final rolling temperature and corrected by the rolling speed, (v bite ′) p is the corrected biting speed for the pth pass, (t ac1 ′) p is the pth pass, the corrected acceleration time after the workpiece bites into the workpiece, (v thr ′) p is the corrected ejection speed for the pth pass, (t de1 ′) p is the pth pass, the corrected deceleration time before the rolled piece is ejected, (L r ) p is the length of the roller surface that the roller rotates during the pth pass, is the critical minimum rolling speed for maintaining the minimum oil film thickness in the pth pass, is the maximum speed of the p-th bite, is the maximum stable rolling speed of the pth pass, (t ac2 ′) p is the roll no-load acceleration time during the p-th pass, i1′ is the corrected roll load acceleration, i2′ is the corrected roll load deceleration, i3′ is the corrected roll no-load acceleration, i4′ is the corrected roll no-load deceleration, is the rated acceleration of the roll when loaded, is the rated deceleration, is the rated acceleration of the roller when it is unloaded, is the rated deceleration.

[0161] Correction of the rolling speed within a pass includes calculations based on the settings in the online self-correction of the rolling speed. Based on the real-time surface quality of the plate in the pass, basic automation is triggered to execute, including the quality defect signal detected by the surface monitor, which is sent to the basic automation to directly execute the speed reduction action. The execution of the speed reduction action includes receiving the quality defect signal detected by the surface monitor to trigger the start of the calculation, following the principle of equal length of the roller surface before and after adjustment, constructing a multi-objective function, constructing constraints, calculating the optimal speed, and correcting the rolling speed of the pass.

[0162] During the rolling process, when the surface detector finds that the surface quality of the plate does not meet the standard or there is aluminum sticking and whitening on the surface, it will directly send a signal to the basic automation to execute the speed reduction action, and grade the whiteness of the plate surface into 10 levels. When the whiteness level increases by 1 level, the rolling speed reduction range is 1% to 3%.

[0163] Another object of the present invention is to provide an aluminum plate and strip roughing mill speed setting system based on multi-objective planning, which can construct a multi-objective function by calculating the parameters in the rolling process, biting conditions, stable rolling conditions, support roller oil film bearing thickness and pass ejection speed, thereby solving the problem of low accuracy in the current aluminum plate and strip roughing mill speed setting method.

[0164] As a preferred solution of the aluminum plate and strip rough rolling mill speed setting system based on multi-objective planning described in the present invention, it includes: a multi-objective function construction module, a constraint function construction module, and a real-time speed correction module; the multi-objective function construction module is used to construct a multi-objective function by calculating the parameters in the rolling process, the biting conditions, the stable rolling conditions, the support roller oil film bearing thickness, and the pass ejection speed; the constraint function construction module is used to construct a constraint function based on the multi-objective function through the final rolling temperature, the surface quality, and the total rolling time; the real-time speed correction module is used to perform optimal speed calculation based on the constraint function, and to correct the rolling speed in real time within the pass.

[0165] A computer device includes a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of a method for setting the speed of an aluminum plate and strip roughing mill based on multi-objective planning.

[0166] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a method for setting the speed of an aluminum plate and strip roughing mill based on multi-objective planning.

[0167] Beneficial effects of the present invention: The speed setting method of the aluminum plate and strip rough rolling mill based on multi-objective planning provided by the present invention constructs a multi-objective function by calculating the parameters in the rolling process, the biting conditions, the stable rolling conditions, the thickness of the support roller oil film bearing and the pass ejection speed. By accurately calculating the parameters directly related to the rolling process, the determination of the rolling speed not only depends on experience or static models, but also reflects the real-time physical conditions and rolling dynamics, improves the accuracy of the rolling parameter setting, ensures that the rolling speed is synchronized with the actual production conditions, and thus optimizes the rolling efficiency and the quality of the aluminum plate and strip; based on the multi-objective function, a constraint function is constructed through the final rolling temperature, surface quality and the total rolling time. The establishment of the constraint function is to ensure that while pursuing the optimization of speed, there will be no Sacrificing the final rolling temperature and surface quality of the product, the method of constructing a constraint function makes the speed adjustment in the production process more purposeful, avoids possible quality problems in production, and ensures the consistency and reliability of the aluminum plate and strip; based on the constraint function, the optimal speed calculation is performed, and the rolling speed is corrected in real time within the pass. The optimal speed calculation is to find the rolling speed with the highest production efficiency while satisfying the constraints, and the real-time correction is to adapt to any changes that may occur in the rolling process. By correcting the rolling speed in real time, the downtime and defective product rate can be reduced, while improving the overall efficiency of the production line and the consistency of the product. The present invention achieves better results in terms of efficiency, economy, reliability, consistency and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0168] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0169] Figure 1 An overall flow chart of a method for setting speed of an aluminum strip roughing mill based on multi-objective programming provided in the first embodiment of the present invention.

[0170] Figure 2 A diagram of the roll rotation direction and workpiece ejection process during the rolling interval of the aluminum plate and strip rough rolling mill speed setting method based on multi-objective planning provided in the first embodiment of the present invention.

[0171] Figure 3 A process diagram of the roll rotation direction and the reduction of rolled pieces during the rolling interval of the aluminum plate and strip roughing mill speed setting method based on multi-objective planning provided in the first embodiment of the present invention.

[0172] Figure 4A diagram of the stopped workpiece during the rolling interval of the speed setting method for an aluminum plate and strip roughing mill based on multi-objective planning provided in the first embodiment of the present invention.

[0173] Figure 5 The first embodiment of the present invention provides a method for setting the speed of an aluminum plate and strip rough rolling mill based on multi-objective planning, and a diagram of the roll rotation direction and the re-engagement of the rolled piece during the rolling interval.

[0174] Figure 6 A diagram of the speed changes of the rolling mill rolls and the workpiece during the rolling interval of the aluminum plate and strip roughing mill speed setting method based on multi-objective planning provided in the first embodiment of the present invention.

[0175] Figure 7 A diagram showing the influence of the biting and ejecting speeds on the rolling time of the speed setting method for an aluminum plate and strip rough rolling mill based on multi-objective programming provided in the first embodiment of the present invention.

[0176] Figure 8 A speed comparison diagram before and after the rolling speed is adjusted for the aluminum plate and strip roughing mill speed setting method based on multi-objective planning provided in the first embodiment of the present invention.

[0177] Fig. 9 A flow chart of rolling speed setting calculation and self-correction calculation of an aluminum plate and strip roughing mill speed setting method based on multi-objective programming provided in the first embodiment of the present invention.

[0178] Fig.10 An overall flow chart of an aluminum strip roughing mill speed setting system based on multi-objective programming provided in the third embodiment of the present invention. DETAILED DESCRIPTION

[0179] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0180] Example 1

[0181] Reference Figure 1-Figure 9 , which is an embodiment of the present invention, provides a speed setting method for an aluminum strip roughing mill based on multi-objective programming, comprising:

[0182] S1: A multi-objective function is constructed by calculating the parameters during rolling, the biting condition, the stable rolling condition, the thickness of the oil film bearing of the support roll, and the ejection speed of each pass.

[0183] Furthermore, usually, the friction coefficient is obtained by a table lookup method, and the critical value algorithm of the rolling speed is inferred from the calculation of the friction coefficient. When hot rolling aluminum plates, the friction coefficient is accurately calculated and expressed as:

[0184] f=λ n ·λ v ·λ c ·λ s ·λ l ·λ r (0.84-0.0004t)

[0185] Where f is the friction coefficient, λ n To consider the influence coefficient of the roll material, λ v is the coefficient considering the roller speed, λ c To consider the coefficients of chemical elements in the rolled product, λ s is the coefficient considering the ratio of the roughness of the workpiece surface and the roller surface, λ l is the coefficient considering the aspect ratio of the deformation zone, λ r This is the coefficient to consider the emulsion composition, and t is the temperature of the rolled piece.

[0186] The values ​​of the friction coefficient can be accurately calculated by looking up the table according to the actual situation of the production line. For example, when the roller material is cast iron or aluminum, the corresponding λ n It can be found through the corresponding experience data table.

[0187] It should be noted that, from the critical conditions of the biting stage and the stable rolling stage, the critical values ​​of the friction coefficient in the two stages are respectively taken as:

[0188] f y =tanα y

[0189]

[0190] Among them, f y is the critical value of the friction coefficient between the roll and the workpiece during biting, α y is the bite angle, f w is the critical value of the friction coefficient between the roll and the workpiece during stable rolling, α w K is the contact angle in the stable rolling stage. x is the regression coefficient of the formula.

[0191] When the case of "pressing down with aluminum" is not considered, there is α w =α y Generally speaking, K x ≈2.

[0192] Substituting the calculation formula of the bite angle tangent into the formulas for the critical values ​​of the friction coefficient at the two stages, and combining the formula to accurately calculate the friction coefficient formula, the critical condition of bite can be obtained, which is expressed as:

[0193]

[0194] in, is the coefficient of the roll speed when biting, R is the roll diameter, H is the pass entrance thickness, h is the pass exit thickness, λ s1 is the contact surface morphology coefficient of the workpiece head, and t1 is the temperature of the workpiece head.

[0195] make Arranged, expressed as:

[0196]

[0197] Similarly, the coefficient corresponding to the maximum speed limit value during stable rolling is expressed as:

[0198]

[0199] in, The coefficient of the roll speed is considered for stable rolling, t2 is the temperature of the workpiece excluding the head of the workpiece, and λ s2 It is the contact surface morphology coefficient of the rolled piece excluding the head of the rolled piece.

[0200] According to the actual production data, the formula after sorting and the formula of the coefficient corresponding to the maximum speed limit value during stable rolling can be found in the table, and the coefficients corresponding to the five influencing factors on the right can be obtained, so as to obtain λ v The value of λ can be found from the empirical data table. v The maximum critical speed based on biting and stable rolling conditions can be obtained by linear interpolation. and

[0201] It should be noted that the oil film thickness of the hydrodynamic bearing of the support roller changes continuously with the change of rolling conditions during use. The basic rules are as follows: under the same rolling force, the lower the rolling speed, the smaller the oil film thickness; for the same rolling speed, the greater the rolling force, the smaller the oil film thickness; if the rolling speed is too low and the rolling force is too large, direct contact between the outer ring metal and the inner ring metal of the bearing may occur, causing damage to the bearing.

[0202] Therefore, under the condition of given rolling force, for the hydrodynamic bearing to operate stably and safely, its rotation speed must exceed its critical value.

[0203] The calculation of the critical minimum film thickness of hydrodynamic lubrication was started. Based on Hamrock's research on isothermal elastic fluid lubrication of elliptical contacts, a more accurate formula was proposed. This formula depends on the geometry of the two solids with different curvature radii in contact. The curvature is expressed as the sum of the radii in the x and y directions:

[0204]

[0205]

[0206] Among them, R x is the effective radius in the x direction, r Ax is the radius of curvature of solid A in the x direction, r Bx is the radius of curvature of solid B in the x direction, R y is the effective radius in the y direction, r Ay is the radius of curvature of solid A in the y direction, r By is the radius of curvature of solid B in the y direction.

[0207] Under the action of normal load, the contact area between solids is an ellipse, and the ellipticity kl of the contact area is calculated by the following formula:

[0208]

[0209] The contact is fluid lubrication or mixed lubrication according to the working conditions; that is, whether there is enough lubricant in the contact area to maintain the minimum oil film thickness; the hydrodynamic lubrication in the oil film bearing of the rolling mill support roll can be considered as full fluid lubrication; in full fluid lubrication, the calculation of the minimum oil film thickness is expressed as:

[0210] h min =3.63U 0.68 G 0.49 W -0.73 (1-e -0.68kl )

[0211] Among them, h min is the minimum oil film thickness, U is the velocity parameter in the dimensionless parameters, G is the material parameter in the dimensionless parameters, and W is the load parameter in the dimensionless parameters.

[0212] The calculation of the dimensionless parameter velocity parameter U is expressed as:

[0213]

[0214] Among them, η is the atmospheric viscosity, uv is the average surface velocity in the x direction, and E′ is the comprehensive elastic modulus.

[0215] The material parameters in dimensionless parameters are expressed as:

[0216]

[0217] Where F is the rolling force.

[0218] The load parameter in dimensionless parameters is expressed as:

[0219] G=α1E′

[0220] Where α1 is the pressure viscosity constant.

[0221] The comprehensive elastic modulus E' is expressed as:

[0222]

[0223] in, is the Poisson's ratio of solid A, is the Poisson's ratio of solid B, E A is the elastic modulus of solid A, E B is the elastic modulus of solid B.

[0224] The calculation of the critical minimum rolling speed for dynamic lubrication is started. First, the critical minimum rolling speed that can maintain the minimum oil film thickness for dynamic lubrication is calculated. The oil film thickness h f It can be expressed by Reynolds equation as:

[0225]

[0226] X=c1γv / P

[0227] Among them, X is the Sommerfeld variable, γ is the oil viscosity, v is the rolling speed, P is the rolling force, δ is the diameter gap difference between the bearing and the roll neck, and a1, b1 and c1 are constants.

[0228] The constant c1 is expressed as:

[0229]

[0230] Among them, l is the bearing width, D is the support roller diameter, and d is the journal diameter.

[0231] The oil film thickness h f The relationship between rolling speed and minimum oil film thickness can be inversely calculated using the formula and constant c1, which is expressed as:

[0232]

[0233] So far, the critical minimum rolling speed to establish the minimum oil film thickness is In each rolling pass of aluminum, zero-speed biting rolling often occurs. The rolling force is very large, but the oil film bearing is not damaged, which shows that the oil film has a long storage time. However, for the safety of the bearing, it is best not to use zero-speed biting and zero-speed throwing, but to use low-speed biting and low-speed throwing.

[0234] Start the pass throwing speed calculation.

[0235] When rolling is carried out to the centering, aluminum transfer and temperature waiting pass, the aluminum throwing distance is fixed. In the ordinary rolling pass, in order to ensure that the rollers obtain the biting speed to establish the minimum oil film thickness of the bearing, a certain aluminum throwing distance must be left. During the rolling process, the rollers and the working rollers in front and behind the machine keep in a follow-up state, that is, the linear speeds of the two are kept consistent. Figure 2-Figure 5 , is the whole process of the change of the speed of the roll and the workpiece from the time when the workpiece is thrown out to the next bite. First, the roll rotates counterclockwise. When the workpiece is thrown out from the roll gap of the rolling mill, the workpiece moves away from the rolling mill and gradually decelerates to a stop as the roller decelerates. Then the roller rotates in the opposite direction to drive the workpiece to move toward the rolling mill. The workpiece continues to accelerate until it bites into the roll gap of the rolling mill again. Through analysis, it can be seen that the follow-up speed of the roll and the roller is not always the same as the speed of the workpiece. Usually, the workpiece has not reached the preset aluminum throwing point, and the roller has completed the process of dropping to zero speed or even accelerating in the opposite direction. After that, the workpiece slides to the aluminum throwing point by inertia, which greatly reduces the aluminum throwing distance reserved for achieving the biting speed to maintain the oil film thickness.

[0236] Assume that the speeds of the roller and the workpiece during the aluminum throwing and the next aluminum biting are v thr 、v bir 、v ths 、v bis ,like Figure 2-Figure 5 In the intermittent rolling process shown in the figure, at the moment when the roller throws aluminum, the speed of the workpiece can be considered to be equal to the linear speed of the roller and the roller table. At this time, there is no relative movement between the roller table and the workpiece, and the friction force is zero. Subsequently, the roller table is driven by the motor to decelerate continuously, and the workpiece moves relative to the roller table due to inertia and is subjected to friction in the opposite direction of movement. When the roller table speed drops to zero, the workpiece still maintains a small speed in the original direction of movement. Thereafter, the roller table accelerates in the reverse direction, and the speed of the workpiece drops to zero under the action of friction and then accelerates in the reverse direction. When the workpiece is bitten again, there is v bis ≤v bir , v bis is the biting speed of the rolled piece, v bir It is the speed of the roller when the workpiece bites.

[0237] refer to Figure 6, is the speed change of the roll and the workpiece during rolling interval, where the ordinate is speed and the abscissa is time. The dotted line is the workpiece speed curve, and the solid line is the roll speed curve. Since the mass of the workpiece and the friction coefficient between the workpiece and the roller are basically constant, the friction force on the workpiece is also constant. It can be seen that the workpiece always moves at a uniform speed, and its dotted line speed curve is a straight line, while the absolute value of the acceleration of the roll before and after the reverse direction may be different, and its solid line speed curve may be a broken line.

[0238] Now we make a quantitative calculation of this process. Assuming the speed of aluminum casting is v1, we have v ths =v thr =v1,v ths is the ejection speed of the rolled piece, v thr is the speed of the roller when casting aluminum, and the time for the roller and the workpiece to drop from v1 to zero is t r1 ,t s1 The time from rest to maximum speed is t r2 ,t s2 , the deceleration and acceleration are q1 and q2, the mass of the rolled piece is m, and the aluminum throwing distance is S s The maximum distance the roller turns is S r The friction force is F m , the acceleration is a s , the sliding friction coefficient between the roller and the rolled product is μ.

[0239] During the entire intermittent process, the temperature change of the rolled piece is small, and the relative sliding speed between it and the roller is also small. Therefore, it can be considered that the friction coefficient μz is constant, and the acceleration of the rolled piece is expressed as:

[0240]

[0241] Where g is the acceleration due to gravity.

[0242] The expressions of all motion states of the rolled product and the roller are as follows. When the product is far away from the rolling mill, it is expressed as:

[0243] S s =0.5a s t s1 2

[0244] t s1 =v1 / a s

[0245] S r =0.5q1t r1 2

[0246] S r =0.5q1t r12

[0247] When approaching the rolling mill, four situations are considered.

[0248] In the first case, when the workpiece bites into the rolling mill, the roller just reaches the maximum speed determined by the limiting conditions, which is expressed as:

[0249] t r1 +t r2 =t s1 +t s2

[0250] S s =0.5a s t s2 2

[0251] t s2 =v bis / a s

[0252] S r =0.5q2t r2 2

[0253] t r2 =v bir / q2

[0254] In the first case,

[0255] In the second case, when the workpiece bites into the rolling mill, the roller just reaches the minimum speed determined by the oil film thickness condition. According to the expression of the first case, in the second case, we have

[0256] The third case: When the workpiece does not bite into the rolling mill, the roller has reached the maximum speed determined by the bite condition. After that, the roller rotates at a constant speed at the maximum speed until the workpiece bites into the rolling mill. Let the uniform speed time of the roller and the workpiece be t r3 ,t s3 , expressed as:

[0257] t r1 +t r2 +t r3 =t s1 +t s2 +t s3

[0258] For the roller, it is expressed as:

[0259]

[0260]

[0261] For rolled products, When , it means that the rolled piece is always under stress and accelerated state, which can be expressed as:

[0262] S s =0.5a s t s2 2

[0263]

[0264] when When , it means that the rolled piece moves at a uniform speed together with the roller after accelerating to the maximum, which can be expressed as:

[0265]

[0266]

[0267] In the formula,

[0268] The fourth situation: when the workpiece bites into the rolling mill, the speed of the roller is between the maximum speed and the minimum speed determined by the limiting conditions. Since it does not involve the calculation of the critical value, it is not considered for the time being.

[0269] It is easy to judge that in the second case, since the speed of the rolling roller is the lowest when biting aluminum, the interval time is the shortest, and the aluminum throwing distance is the smallest, we will now focus on analyzing the second case.

[0270] Because the rolled piece always moves at a uniform speed, t s1 =t s2 , v bis =v1, the whole intermittent time is calculated by the rolled product and expressed as:

[0271]

[0272] Among them, t inter Rolling interval time.

[0273] Within this interval time, the roller must complete the action of reducing speed to zero and increasing speed to the minimum speed. The interval time calculated by the roller is expressed as:

[0274]

[0275] The minimum aluminum casting speed determined by the horizontal direction is expressed as:

[0276]

[0277] Among them, v x It is the minimum aluminum casting speed determined by the horizontal direction.

[0278] The minimum aluminum throwing distance determined by the minimum aluminum throwing speed and the friction coefficient between the roller and the rolled piece is expressed as:

[0279]

[0280] In addition, the rolling interval must be greater than the swing roll gap time t of the pressing motor. vert Otherwise, there will be unexpected aluminum pressing, and cause the pressing motor to overcurrent, that is: t r1 +t r2 ≤t vert , substituting the calculated intermittent time expression into the minimum aluminum casting speed determined by the vertical direction can be expressed as:

[0281]

[0282] Among them, t vert is the swing roller gap time of the pressing motor, v y It is the minimum aluminum casting speed determined by the vertical direction.

[0283] Minimum aluminum casting speed is v x and v y The smaller value of It is the minimum aluminum casting speed.

[0284] The maximum critical value of aluminum casting speed is consistent with the maximum speed during stable rolling, which is It is the maximum aluminum casting speed.

[0285] S2: Based on the multi-objective function, the constraint function is constructed through the final rolling temperature, surface quality and total rolling time.

[0286] Furthermore, mathematical modeling was first performed with the goal of achieving a good final rolling temperature and maximum production efficiency.

[0287] Reasonable biting, ejection speed and maximum rolling speed can make the t of this pass roll Rolling time and t inter The sum of rolling interval time is the shortest, reference Figure 7 , the y-axis is the rolling speed, the x-axis is the time, v b1 、v t1 and v b2 They represent the linear speeds of low-speed biting, low-speed throwing and low-speed biting again, v b11 、v t11 and v b21 They represent the speeds of relatively high-speed biting, high-speed throwing and high-speed biting again. Under the premise of ensuring that the area under the biting to throwing speed curve is equal, high-speed biting and high-speed throwing make the pure rolling time t roll1 shortened, but it made the gap time tinter1 Increase, on the contrary, adopt low speed bite and low speed throw, although the pure rolling time t roll Increase, but can make the gap time t inter Therefore, choosing the appropriate bite speed and ejection speed will minimize the rolling time of the pass, shorten the rolling cycle, and thus increase the output of the rolling mill.

[0288] Firstly, the first objective function is determined, that is, the final rolling temperature objective function with rolling speed and time as control variables.

[0289] The optimization of ordinary rolling passes during aluminum plate rolling is discussed as the object of discussion. Special passes include heavy shearing of the head and tail, material transfer, and centering passes. The speed of special passes should be set separately according to the actual situation and no optimization is required. Assume that the number of passes required for edge rolling of the vertical roller mill is n1, the number of ordinary passes is n, and the bite speed of the jth pass is (v bite ) j , the stable rolling speed is (v sta ) j , the duration is (t sta ) j , aluminum casting speed is (v thr ) j During rolling, the acceleration of the roller is i1, the deceleration is i2, and the acceleration time is (t ac1 ) j , deceleration time is (t de1 ) j , the final rolling temperature limited by the process is T set The allowable error of the final rolling temperature is ε T , the waiting temperature is T ctrl , the pass exit length of the rolled piece is (L s ) j The length of the roller rotation is (L r ) j , the amount of pressure reduction is (Δh) j , the no-load acceleration of the roller during the inter-pass interval is i3, the no-load deceleration is i4, and the acceleration time is (t ac2 ) j , deceleration time is (t de2 ) j , the total time required for the vertical roller hemming pass is t edge , rated acceleration when loaded is Rated deceleration is The rated acceleration when no load is Rated deceleration is

[0290] Due to the existence of forward slip during the rolling process, the length of the roll surface rotation is slightly smaller than the exit length of the rolled piece, and the calculation formula is expressed as:

[0291]

[0292] Among them, L r S is the length of the roll surface during rolling. h is the forward slip value, L s is the length of the rolled piece, and Δh is the reduction per pass.

[0293] In a rolling pass, the relationship between the roll speed and time can be described as:

[0294]

[0295] v sta =v bite +i1t ac1 =v thr +i2t de1

[0296] Among them, v sta To stabilize the rolling speed, v bite is the biting speed, t sta is the stable rolling time, t ac1 is the acceleration time of the roll during rolling, t de1 It is the deceleration time of the roller rotation during rolling.

[0297] In a rolling interval, the relationship between the roll speed and time can be described as:

[0298] v bite =i3·t ac2

[0299] v thr =i4·t de2

[0300] Among them, t ac2 is the no-load acceleration time, t de2 It is the no-load deceleration time.

[0301] The total rolling time can be expressed as:

[0302]

[0303] Among them, t all is the total rolling time, t roll is the rolling time, t z A coefficient for adjusting the interval time of the next few passes.

[0304] The total rolling time is calculated by the total pure rolling time∑t roll and the total rolling interval time ∑t interThe sum of the pure rolling time is composed of the acceleration time, deceleration time and constant speed time of the j passes, and the intermittent time is composed of.

[0305] Substituting into the three equations in one rolling pass, we can get:

[0306]

[0307] If the rolling speed is within the critical value range, the final temperature of the rolled piece cannot meet the following conditions: (T set -ε T )≤T end ≤(T set +ε T ), that is, the iteration operation ends, T end is the final rolling temperature, and both the effective solution and the weak effective solution of the objective function are infeasible solutions, t z It is the coefficient for adjusting the interval time of the next few passes, that is, the static waiting time when the rolled piece is at the maximum aluminum throwing distance, and its initial value is 0.

[0308] The heat radiation and convection of the rolled piece run through the entire rolling stage, and the time is t all , the temperature drop function of the rolled piece corresponding to thermal radiation and convection is expressed as:

[0309] T emi =f(t all )

[0310] Among them, T emi is the temperature drop function of the rolled piece corresponding to thermal radiation and convection, f(t all ) is the functional formula of the temperature drop of the rolled piece corresponding to thermal radiation and convection.

[0311] The temperature drop of emulsion spray is T emul , the temperature rise caused by plastic work and deformation heat is T def The time of heat conduction in contact with the roller is t roll The temperature drop function of the rolled piece due to roller contact heat conduction is T con =f(t roll ).

[0312] The main objective function determined by the final rolling temperature is expressed as:

[0313] F(v bite ,v thr ,v sta )=T ctrl -T emi -T emul -T con +T def =T ctrl -f(t all )-Temul -f(t roll )+T def

[0314] Among them, F(v bite ,v thr ,v sta ) is the main objective function determined by the final rolling temperature.

[0315] Iterate until |F(v bite ,v thr ,v sta )-T set |≤ε T Stop, if the final rolling temperature determines the main objective function F(v bite ,v thr ,v sta ) has no feasible solution, then t z =t z ±α z , α z is the search step length.

[0316] In order to obtain the secondary objective function determined by the minimum total rolling time, it is expressed as:

[0317] G(v bite ,v thr ,v sta ) = t all

[0318] Among them, G(v bite ,v thr ,v sta ) is the secondary objective function determined by minimizing the total rolling time.

[0319] Transform the first objective function into the auxiliary constraint of the second objective function, and establish all the constraints in parallel. Then the mathematical model of the optimization problem can be expressed as:

[0320] min G((v bite ) j ,(v thr ) j ,(v sta ) j )

[0321] St|F((v bite ) j ,(v thr ) j ,(v sta ) j )-T set |≤ε T

[0322]

[0323]

[0324]

[0325] (v sta ) j -(v bite ) j +i1·(t ac1 ) j =0

[0326] (v sta ) j -(v thr ) j +i2·(t de1 ) j =0

[0327] (v bite ) j -i3·(t ac2 ) j =0

[0328] (v thr ) j -i4·(t de2 ) j =0

[0329]

[0330]

[0331]

[0332]

[0333] Among them, G((v bite ) j ,(v thr ) j ,(v sta ) j ) is the main objective function determined by the final rolling temperature at the jth pass, F((v bite ) j ,(v thr ) j ,(v sta ) j ) is the secondary objective function determined by the minimum total rolling time of the jth pass, St is the constraint symbol, is the critical minimum rolling speed to maintain the minimum oil film thickness in the jth pass, is the maximum speed of the j-th bite, is the maximum stable rolling speed of the jth pass.

[0334] The multi-objective problem is then transformed into an optimization problem of an objective function, which is solved using the augmented multiplier method in the constrained nonlinear optimization algorithm.

[0335] S3: Based on the constraint function, the optimal speed calculation is performed, and the rolling speed is corrected in real time within the pass.

[0336] Furthermore, to solve the mathematical model, we first observe the constraints in the mathematical model expression of the optimization problem. From the beginning to the end, there are 12n inequality constraints and 4n equality constraints, which are converted into g e (v)≥0(e=1,2,...,12n) and h l (v)=0(l=1,2,3,4n), g e (v) is the inequality constraint function, e is the number of inequality constraints, h l (v) is the equality constraint function, l is the number of equality constraints, then the augmented Lagrangian function can be expressed as:

[0337]

[0338] in, is the augmented Lagrangian function, G(v) is the objective function, σ is the penalty coefficient, which is greater than 0, and λ e is the Lagrange multiplier associated with the e-th inequality constraint, λ is a vector including the Lagrange multipliers associated with the equality constraint, μ is a vector including the Lagrange multipliers associated with the inequality constraint, μ l is the Lagrange multiplier associated with l equality constraints, and T is the mathematical symbol for the horizontal row of column vectors.

[0339] σ>0 is a sufficiently large parameter; μ=(μ1,...,μ 4n ) T ;λ=(λ1,...,λ 12n ).

[0340] By modifying the multiplier λ in the kth iteration (k) and μ (k) , and obtain the multiplier λ in the k+1th iteration (k+1) and μ (k+1) , modified formally, expressed as:

[0341]

[0342]

[0343] in, is the k+1th iteration of the algorithm, and the inequality g e (v) Updated value of the associated Lagrange multiplier, g e (v (k) ) is the value of the equation constraint in the kth iteration, h e (v (k) ) is the value of the inequality constraint in the kth iteration, is the Lagrange multiplier associated with the l equality constraints, which is the value after the k+1th iteration.

[0344] The iteration termination criterion is expressed as:

[0345]

[0346] Among them, δ (k) is a metric used to evaluate the degree of constraint violation at the kth iteration. It is the square root of the sum of the squares of the equality constraints and the squares of the inequality constraints violated. l 2 (v (k) ) is the equality constraint h at the kth iteration. l The value of μ e (k) is the inequality constraint g at the kth iteration. e (v) The value of the associated penalty multiplier, ε is the maximum allowable error value for violating the constraint during iteration.

[0347] The calculation steps include Step 1: Given the initial point v (0) is the initial vector for iterative velocity calculation, To set the initial values ​​of the j-th pass bite speed, ejection speed, and stable rolling speed to the critical minimum rolling speed to maintain the minimum oil film thickness, the initial estimate of the multiplier vector μ = λ = (1,...,1) T , take σ = 2, allowable error ε> 0, take constant θ> 1, θ is the step size parameter used to adjust the iterative convergence speed, In order to determine whether it is necessary to adjust the optimization parameters of the iterative convergence speed, set k=1.

[0348] Step 2 is to use v (k-1) As the initial point, solve the unconstrained problem Solved (k) .

[0349] Step 3 is to calculate δ (k) , if the expression selected by the iteration termination criterion is satisfied, the calculation is stopped and the solution v is obtained (k) ; Otherwise, go to Step 4.

[0350] Step 4 is to judge the convergence speed. Then let σ=θσ and go to Step 5; otherwise, go directly to Step 5.

[0351] Step 5 is to calculate using the modified expression and Set k=k+1 and go to Step 2.

[0352] It should be noted that, assuming that the surface detector finds defects in the plate at the jth pass, based on the above analysis, the speeds of the remaining (nj) passes need to be appropriately lowered under both low and high speed conditions. Assuming that the adjustment step of the stable rolling speed is β (which can be manually set on the human-machine interface), the adjusted stable rolling speed is expressed as:

[0353] (v sta ′) j+1 =(v sta ) j+1 (1-β)

[0354] Among them, (v sta ′) j+1 is the j+1th pass, the adjusted stable rolling speed, (v sta ) j+1 is the stable rolling speed of the j+1th pass without adjustment.

[0355] If the rolling mill executes the adjusted rolling speed in the current pass, and the surface detector still detects that the surface quality is unqualified, the subsequent passes will continue to be executed, which is expressed as:

[0356] (v sta ′) j+2 =(v sta ) j+2 (1-β)

[0357] Among them, (v sta ′) j+2 is the j+2th pass, the adjusted stable rolling speed, (v sta ) j+2 is the stable rolling speed without adjustment in the j+2th pass.

[0358] In addition, the principle of keeping the length of the roller surface rotated by the roller before and after adjustment consistent must be followed, which requires that the areas of the two parts are equal, that is, S abcdef =S a′b′c′d′e′f =L r , after integrating the area value, it can be expressed as:

[0359]

[0360] Among them, a is the bite time point before the rolling speed correction of this pass, f c is the ejection time point before the rolling speed correction of this pass, a′ is the bite time point after the rolling speed correction of this pass, and f c ′ is the ejection time point after the rolling speed of this pass is corrected, v(t) is the speed curve before the rolling speed of this pass is corrected, and v′(t) is the speed curve before the rolling speed of this pass is corrected.

[0361] Expanding the integral gives:

[0362]

[0363] Among them, v sta ′ is the corrected stable rolling speed, v bite ′ is the corrected bite speed, t ac1 ′ is the roll acceleration time during the corrected rolling, v thr ′ is the corrected aluminum casting speed, t de1 ' is the deceleration time for correction.

[0364] Among them, v(t) and v′(t) are the rolling speed curves before and after adjustment, respectively. Figure 7 .

[0365] Then the speed correction calculation for the (nj) passes is expressed as:

[0366] min G((v bite ′) p ,(v thr ′) p ,(v sta ′) p )

[0367]

[0368]

[0369]

[0370]

[0371] (v sta ′) p -(v bite ′) p +i1·(t ac1 ′) p =0

[0372] (v sta ′) p -(v thr ′) p+i2·(t de1 ′) p =0

[0373] (v bite ′) p -i3·(t ac2 ′) p =0

[0374] (v thr ′) p -i4·(t de2 ′) p =0

[0375]

[0376]

[0377]

[0378]

[0379] Among them, G((v bite ′) p ,(v thr ′) p ,(v sta ′) p ) is the main objective function of the pth pass, which is determined by the final rolling temperature and corrected by the rolling speed, (v bite ′) p is the corrected biting speed for the pth pass, (t ac1 ′) p is the pth pass, the corrected acceleration time after the workpiece bites into the workpiece, (v thr ′) p is the corrected ejection speed for the pth pass, (t de1 ′) p is the pth pass, the corrected deceleration time before the rolled piece is ejected, (L r ) p is the length of the roller surface that the roller rotates during the pth pass, is the critical minimum rolling speed for maintaining the minimum oil film thickness in the pth pass, is the maximum speed of the p-th bite, is the maximum stable rolling speed of the pth pass, (t ac2 ′) p is the roll no-load acceleration time during the p-th pass, i1′ is the corrected roll load acceleration, i2′ is the corrected roll load deceleration, i3′ is the corrected roll no-load acceleration, i4′ is the corrected roll no-load deceleration, is the rated acceleration of the roll when loaded, is the rated deceleration, is the rated acceleration of the roller when it is unloaded, is the rated deceleration.

[0380] For correction of rolling speed within a pass, refer to Fig. 9 According to the set calculation, the rolling speed of the subsequent pass can be corrected according to the surface quality of the plate in the current pass. However, this is not enough in actual production. It is also necessary to directly adjust the rolling speed of this pass through the basic automation to ensure that the surface quality of the plate in the current pass is intact. During the rolling pass, when the surface detector finds that the surface quality of the plate does not meet the standard or there is aluminum sticking or whitening on the surface, it will directly send a signal to the basic automation to execute the speed reduction action. The plate surface can be graded according to the whiteness, which can be divided into 10 levels. When the whiteness level increases by 1 level, the rolling speed is reduced by 1%-3%.

[0381] Example 2

[0382] One embodiment of the present invention provides a speed setting method for an aluminum strip roughing mill based on multi-objective programming. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0383] Configure the rolling mill and computing equipment to ensure the normal operation of all equipment, use existing technology for rolling, record the key parameters of rolling speed and aluminum plate surface quality as baseline data, apply the present invention for rolling, also record the key parameters, repeat the baseline test and new technology test multiple times to ensure the reliability and consistency of the data.

[0384] The key parameters in the rolling process, including the rolling speed, the aluminum plate surface quality rating, and the rolling time in the production efficiency index, are recorded and analyzed. Referring to Table 1, a comparative analysis of the present invention and the prior art in the optimization of the rolling process is shown.

[0385] Table 1 Comparative analysis of the present invention and the prior art in rolling process optimization

[0386]

[0387]

[0388] Compared with the prior art, the present invention shows significant advantages in rolling speed, aluminum plate surface quality rating and rolling time. The present invention can significantly improve the surface quality rating of the aluminum plate while increasing the rolling speed, and reduce the rolling time, which shows that the present invention has significant improvements in improving production efficiency and product quality. While solving the problems of the prior art, the present invention has higher innovation and advantages. Therefore, our invention is creative.

[0389] Example 3

[0390] Reference Fig.10 , which is an embodiment of the present invention, provides an aluminum plate and strip roughing mill speed setting system based on multi-objective planning, including a multi-objective function building module, a constraint function building module, and a real-time speed correction module.

[0391] The multi-objective function construction module is used to construct a multi-objective function by calculating the parameters in the rolling process, biting conditions, stable rolling conditions, support roller oil film bearing thickness and pass ejection speed. The constraint function construction module is used to construct a constraint function based on the multi-objective function through the final rolling temperature, surface quality and total rolling time. The real-time speed correction module is used to perform optimal speed calculation based on the constraint function, and to correct the rolling speed in real time within the pass.

[0392] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0393] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0394] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0395] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc. It should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limited. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

[0396] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A speed setting method for aluminum strip roughing mill based on multi-objective programming, characterized in that: include: A multi-objective function is constructed by calculating the parameters of the rolling process, the bite conditions, the stable rolling conditions, the thickness of the oil film bearing of the support rolls, and the throw-out speed of each pass; Based on the multi-objective function, the constraint function is constructed through the final rolling temperature, surface quality and total rolling time; Based on the constraint function, the optimal speed calculation is performed, and the rolling speed and the rolling speed within the pass are corrected in real time; The real-time correction of the rolling speed and the rolling speed within the pass includes arranging an aluminum plate and strip surface detector after the rolling mill, monitoring the quality of the strip surface in real time, and correcting the preset parameters of the rolling mill speed in real time based on the feedback results of the strip surface detector, setting the speed curves of all passes in the rolling process, and correcting the stable rolling speed, aluminum biting speed and aluminum throwing speed of the remaining passes in real time based on the strip surface quality, and performing speed reduction adjustment to make the final rolling temperature lower than the final rolling temperature before adjustment; When the surface quality is an influencing factor or the final rolling temperature does not change based on the speed adjustment, the speed is reduced. When the surface quality is not an influencing factor, the speed is not reduced and changes are made based on product performance requirements. The speed reduction is included in the During the first pass, the surface detector found defects in the plate. When rolling at low and high speeds, the remaining The speed of each pass is lowered, and the adjustment step length for the stable rolling speed is , the adjusted stable rolling speed is expressed as: in, is the j+1th pass, the adjusted stable rolling speed, is the stable rolling speed of the j+1th pass without adjustment; When the rolling mill executes the adjusted rolling speed in the j+1 pass, the surface detector detects that the surface quality is unqualified, and the pass continues to be executed, which is expressed as: in, is the j+2th pass, the adjusted stable rolling speed, is the stable rolling speed without adjustment at the j+2th pass; Based on the principle that the length of the roller surface rotated by the roller before and after adjustment should be consistent, the area of ​​the two parts will be equal. , is the area of ​​hexagon abcdef, Hexagonal After integrating the area value, it is expressed as: in, is the bite time point before the rolling speed correction of this pass, is the throwing time point before the rolling speed correction of this pass, is the bite time point after the rolling speed is corrected for this pass, is the ejection time point after the rolling speed of this pass is corrected, is the speed curve before rolling speed correction for this pass, The speed curve before the rolling speed correction of this pass; Expand the integral and it can be expressed as: in, To correct the stable rolling speed, To correct the bite speed, To correct the roll acceleration time during rolling, To correct the aluminum polishing speed, Deceleration time for correction; right The speed correction calculation for each pass is expressed as: in, is the main objective function of the p-th pass, determined by the final rolling temperature, after correcting the rolling speed, is the corrected bite speed for the pth pass, is the pth pass, the corrected acceleration time after the workpiece bites into the workpiece, is the corrected ejection speed for the pth pass, is the pth pass, the corrected deceleration time before the rolled piece is ejected, is the length of the roller surface that the roller rotates during the pth pass, is the critical minimum rolling speed for maintaining the minimum oil film thickness in the pth pass, is the maximum speed of the p-th bite, is the maximum stable rolling speed of the pth pass, is the no-load acceleration time of the roll during the interval between rolling passes at the pth pass, is the corrected acceleration of the roll under load, is the corrected deceleration of the roll under load, is the corrected acceleration of the roller when it is unloaded, is the corrected deceleration of the roll when it is unloaded, is the rated acceleration of the roll when loaded, is the rated deceleration, is the rated acceleration of the roller when it is unloaded, is the rated deceleration; The rolling speed correction within the pass includes, based on the setting calculation in the online self-correction of the rolling speed, based on the surface quality of the plate in the real-time pass, triggering the basic automation execution, including the surface monitor detecting the quality defect signal, sending it to the basic automation to directly execute the speed reduction action, executing the speed reduction action includes receiving the quality defect signal detected by the surface monitor to trigger the calculation start, following the principle of equal length of the roller surface before and after adjustment, constructing a multi-objective function, constructing constraints, performing the optimal speed calculation, and correcting the rolling speed within the pass; During the rolling process, when the surface detector finds that the surface quality of the plate does not meet the standard or there is aluminum sticking or whitening on the surface, it will directly send a signal to the basic automation to execute the speed reduction action, and grade the whiteness of the plate surface into 10 levels. When the whiteness level increases by 1 level, the rolling speed reduction range is 1% to 3%.

2. The speed setting method for an aluminum strip roughing mill based on multi-objective programming according to claim 1, characterized in that: The multi-objective function construction includes calculating the parameters in the rolling process. In the rolling process, based on the influence of the rolling lubricant, the friction coefficient between the rolled piece and the roller is obtained by a table lookup method, and the critical value algorithm of the rolling speed is obtained by reverse calculation through the calculation of the friction coefficient. When the aluminum plate is hot rolled, the friction coefficient is calculated and expressed as: in, is the friction coefficient, is the influence coefficient of the roll material, is the influence coefficient of the roller speed, is the influence coefficient of chemical elements in the rolled product, is the influence coefficient of the roughness ratio of the workpiece surface and the roller surface, is the influence coefficient of the aspect ratio of the deformation zone, is the influence coefficient of emulsion composition, is the temperature of the rolled piece.

3. The speed setting method for an aluminum strip roughing mill based on multi-objective programming according to claim 2, characterized in that: The construction of the multi-objective function also includes analyzing and calculating the biting conditions and stable rolling conditions during the rolling process, and calculating the friction coefficient in the biting stage and the friction coefficient in the stable rolling stage based on the critical conditions in the biting stage and the stable rolling stage, which are expressed as: in, is the critical value of the friction coefficient between the roll and the workpiece during biting, For the bite angle, The critical value of the friction coefficient between the roll and the workpiece during stable rolling. To stabilize the contact angle during the rolling stage, is the regression coefficient of the formula; Based on the friction coefficient in the biting stage and the friction coefficient in the stable rolling stage, the friction coefficient is calculated, the tangent value of the biting angle is calculated, and the critical condition of biting is obtained, which is expressed as: in, is the influence coefficient of the roll speed during biting, is the roller diameter, is the pass entrance thickness, is the exit thickness of the pass, is the contact surface shape coefficient of the workpiece head, is the temperature of the rolled piece head; Will , sorted, expressed as: The coefficient of stable rolling based on the roll speed factor is expressed as: in, The influence coefficient of the roll speed during stable rolling is: is the temperature of the workpiece excluding the head of the workpiece, It is the contact surface shape coefficient of the rolled piece excluding the head of the rolled piece; based on and , obtained through the empirical data table and The maximum critical speed based on the bite phase is obtained by linear interpolation. , to obtain the maximum critical speed based on the stable rolling stage .

4. The speed setting method for aluminum strip roughing mill based on multi-objective programming according to claim 3, characterized in that: The constructing of the multi-objective function also includes calculating the thickness of the support roller oil film bearing and the pass ejection speed during the rolling process, and calculating the thickness of the support roller oil film bearing and the pass ejection speed during the rolling process includes that at the same rolling force, the rolling speed is proportional to the oil film thickness, and at the same rolling speed, the rolling force is inversely proportional to the oil film thickness; The critical minimum film thickness of dynamic pressure lubrication is calculated. The dynamic pressure lubrication in the oil film bearing of the rolling mill support roll is regarded as full fluid lubrication. Based on the normal load, the contact between the solids is an ellipse. In full fluid lubrication, the minimum oil film thickness is calculated as: in, is the effective radius in the x direction, is the effective radius in the y direction, is the ellipticity of the contact area, is the minimum oil film thickness, is the velocity parameter among dimensionless parameters, is the material parameter among dimensionless parameters, is the load parameter in the dimensionless parameter; The calculation of the critical minimum rolling speed for hydrodynamic lubrication includes calculating the critical minimum rolling speed for maintaining the minimum oil film thickness for hydrodynamic lubrication; Calculate the oil film thickness using the Reynolds equation , expressed as: in, is the Sommerfeld variable, is the diameter clearance difference between the bearing and the roll neck, and is a constant; By back-calculating, the relationship between rolling speed and minimum oil film thickness is obtained, which is expressed as: in, is the critical minimum rolling speed for minimum oil film thickness, is the rolling force, is the oil viscosity, is the diameter clearance difference between the bearing and the roll neck, is a constant; Obtain the critical minimum rolling speed for establishing the minimum oil film thickness ; The speed changes of the rolls and the workpiece during the rolling interval are quantitatively calculated. When aluminum is cast, the speed is , , is the ejection speed of the rolled piece, The speed of the roller when casting aluminum, the roller and the rolled product The time to zero is , The time for the roll and the workpiece to accelerate from rest to maximum speed is , , the deceleration and acceleration of the roller are , The mass of the rolled piece is , the aluminum casting distance is The maximum distance the roller table rotates is The friction force on the roller is , the deceleration and acceleration of the rolled piece are The sliding friction coefficient between the roller and the rolled product is , during the entire intermittent process, the friction coefficient remains unchanged, and the acceleration of the rolled piece is expressed as: Where g is the acceleration due to gravity; When leaving the rolling mill, all the motion states of the workpiece and the rolls are expressed as: When the rolling mill is not reached, there are four situations. The first situation includes when the workpiece bites into the rolling mill and the roller reaches the maximum speed of the limiting condition, which is expressed as: in, Indicates the time from when the rolled piece is stationary to when it bites into the rolling mill. It indicates the time from when the roller is stationary to when the workpiece bites into the rolling mill. Indicates the speed of the rolled piece when it bites into the rolling mill. Indicates the roll speed when the rolled piece bites into the rolling mill, and obtains ; Based on the first case, the second case includes when the workpiece bites into the rolling mill and the roll reaches the minimum speed of the oil film thickness condition, ; The third case includes when the workpiece does not bite into the rolling mill and the roller reaches the maximum speed of the bite condition, the roller rotates at a constant speed at the maximum speed until the workpiece bites into the rolling mill, and the roller uniform speed time is The uniform speed time of the rolled piece is ,and , the roller situation is expressed as: For rolled products, When , the rolled piece is in a state of stress and acceleration, which can be expressed as: when When the rolled piece is accelerated to the maximum and moves at a uniform speed with the roller, it can be expressed as: The third case, satisfying ; The fourth case includes when the workpiece bites into the rolling mill and the speed of the roll is between the maximum speed and the minimum speed of the limiting condition, based on the calculation not involving the critical value, no calculation is performed; In the second case, the rolled piece moves at a uniform speed. , , use the rolled piece to calculate the entire intermittent time, expressed as: in, is the rolling interval time; During the intermittent time, the roller speed drops to zero and increases to the minimum speed. The intermittent time calculated by the roller is expressed as: The minimum aluminum casting speed in the horizontal direction is obtained, which is expressed as: in, The minimum aluminum casting speed determined by the horizontal direction; Based on the minimum aluminum throwing speed and the friction coefficient between the roller and the rolled piece, the minimum aluminum throwing distance is expressed as: The rolling interval time is greater than the swing roll gap time of the pressing motor , based on the intermittent time calculated by the roller, the minimum aluminum casting speed in the vertical direction is obtained, which is expressed as: in, is the swing roller gap time of the pressing motor, The minimum aluminum casting speed determined by the vertical direction; Minimum aluminum casting speed is and The minimum value in , is the minimum aluminum casting speed; The maximum critical value of aluminum casting speed is consistent with the maximum speed during stable rolling. , It is the maximum aluminum casting speed.

5. The speed setting method for aluminum strip roughing mill based on multi-objective programming according to claim 4, characterized in that: The constraining function is constructed by using the final rolling temperature, the surface quality and the total rolling time based on the multi-objective function. Based on the goal of good final rolling temperature and maximum generation efficiency, mathematical modeling includes determining the first objective function, using rolling speed and rolling time as control variables to construct the final rolling temperature objective function. When the aluminum plate is rolled and the head and tail, material and centering passes are heavy, no optimization is performed. When the aluminum plate is rolled and the ordinary rolling passes are performed, the number of passes of the vertical roller mill is , the number of normal channels is , No. In each pass, the bite speed is , the stable rolling speed is , the duration is , aluminum casting speed is , the acceleration of the roller during rolling is , the deceleration is , the acceleration time is , the deceleration time is The final rolling temperature limited by the process is The allowable error of the final rolling temperature is The waiting temperature for the final rolling temperature is The pass exit length of the rolled piece is The length of the roller rotation is , No. The roller reduction in each pass is , the no-load acceleration of the roller during the interpass period is , the no-load deceleration of the roller during the inter-pass interval is , the acceleration time of the roller during the interpass period is , the deceleration time of the roller during the interpass is , the total time of the vertical roller hemming pass is , rated acceleration when loaded is , rated deceleration is , rated acceleration when no load is , rated deceleration is , ; During the rolling process, due to the influence of forward slip, the length of the roll surface rotation is less than the exit length of the rolled piece, which can be expressed as: in, is the length of the roll surface during rolling, is the forward slip value, is the length of the rolled piece, is the amount of reduction per pass; Calculate the total rolling time, expressed as: in, is the total rolling time, is the rolling time, is the pass interval time adjustment coefficient, is the deceleration time of the roller during rolling, To stabilize the rolling time, is the acceleration time of the roller during rolling, is the deceleration time of the roller during rolling, is the no-load acceleration time, is the no-load deceleration time; The total rolling time includes the total pure rolling time and total rolling interval time The total pure rolling time includes the roll acceleration time, deceleration time and constant speed time of j passes. The total rolling time is expressed as: in, To stabilize the rolling speed, is the bite speed; When the rolling speed is within the critical value range, the temperature of the rolled piece does not meet the When , the iteration operation ends. is the final rolling temperature. When all effective solutions or weak effective solutions of the objective function are infeasible solutions, Adjust the static temperature waiting time when the rolled piece is at the maximum aluminum throwing distance, with the initial value being 0; The heat radiation and convection of the rolled piece run through the entire rolling stage. The temperature drop function of the rolled piece corresponding to the heat radiation and convection is expressed as: in, is the temperature drop function of the rolled piece corresponding to thermal radiation and convection, is the functional formula of the temperature drop function of the rolled piece corresponding to thermal radiation and convection; The temperature drop of emulsion spray is , the temperature rise caused by plastic work and deformation heat is The time of heat conduction in contact with the roller is , the temperature drop function of the workpiece due to roller contact heat conduction is , is the temperature drop function of the rolled piece due to the heat conduction from the roller contact, is the functional formula of the temperature drop of the rolled piece due to the heat conduction in contact with the roller; Construct the main objective function of final rolling temperature determination , expressed as: When the iteration meets The iteration stops when the main objective function determined by the final rolling temperature is When there is no solution, , To search for the minimum total rolling time, construct a secondary objective function determined by the final rolling temperature. , expressed as: The main objective function determined by the final rolling temperature is transformed into an auxiliary constraint condition for constructing the secondary objective function determined by the final rolling temperature, and all the constraints are combined. The mathematical model of the optimization problem is expressed as follows: in, is the main objective function determined by the final rolling temperature at the jth pass, is the secondary objective function determined by minimizing the total rolling time of the jth pass, is the constraint symbol, is the critical minimum rolling speed to maintain the minimum oil film thickness in the jth pass, is the maximum speed of the j-th bite, is the maximum stable rolling speed of the jth pass.

6. The speed setting method for aluminum strip roughing mill based on multi-objective programming according to claim 5, characterized in that: The speed optimal calculation includes converting the multi-objective problem into an optimization problem of an objective function based on the constraint function, and using the augmented multiplier method in the constrained nonlinear optimization algorithm to calculate based on the nonlinear factors of the objective function, and the constraint conditions include equality constraints and inequality constraints. Inequalities and 4 equality constraints, which is transformed into and in the form of is the inequality constraint function, is the number of inequality constraints, is the equality constraint function, is the number of equality constraints, and the augmented Lagrangian function is calculated as: in, is the augmented Lagrangian function, is the objective function, is the penalty coefficient, greater than 0, is the Lagrange multiplier associated with the e-th inequality constraint, is a vector containing the Lagrange multipliers associated with the equality constraints, is a vector containing the Lagrange multipliers associated with the inequality constraints, is the Lagrange multiplier associated with l equality constraints, T is the mathematical symbol for the horizontal row of column vectors; By amending the The multiplier in the iteration and , obtain the The multiplier in the iteration and , the revised form is: in, For the algorithm iterations, and the inequality The updated value of the associated Lagrange multiplier, For the The value of the constraint in the iteration, For the The value of the inequality constraint at iterations, is the Lagrange multiplier associated with the l equality constraints; The iteration termination criterion is expressed as: in, For one in A measure to evaluate the degree of constraint violation in iterations, For the At the iteration, the equality constraint The value of For the At the iteration, the inequality constraint The value of the associated penalty multiplier, is the maximum allowable error value for violating constraints during iteration; The calculation process includes initialization, which includes giving an initial point, expressed as: in, is the initial vector for iterative velocity calculation, To set the initial values ​​of the bite speed, ejection speed and stable rolling speed of the jth pass to the critical minimum rolling speed for maintaining the minimum oil film thickness; Initial estimate of the multiplier vector , ,error ,constant , is the step size parameter used to adjust the iterative convergence speed, , In order to adjust the optimization parameters of iterative convergence speed, ; Solve ,include As the initial point, solve the unconstrained problem , get the solution ; calculate , when the iteration termination criteria are met, stop the calculation and obtain the solution ; When the iterative termination criteria are not met, the convergence speed is judged. When , calculated by modifying the formal and ,Will , and solve again , when not satisfied When and ,Will , and solve again .

7. A system using the method for setting the speed of an aluminum strip roughing mill based on multi-objective programming as claimed in any one of claims 1 to 6, characterized in that: Including multi-objective function building module, constraint function building module, real-time correction speed module; The multi-objective function building module is used to build a multi-objective function by calculating the parameters in the rolling process, the bite condition, the stable rolling condition, the thickness of the support roll oil film bearing and the pass ejection speed; The constraint function building module is used to build a constraint function based on a multi-objective function through final rolling temperature, surface quality and total rolling time; The real-time speed correction module is used to perform speed optimization calculation based on the constraint function, and to correct the rolling speed and the rolling speed within the pass in real time.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method for setting the speed of an aluminum strip roughing mill based on multi-objective planning as described in any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for setting the speed of an aluminum strip roughing mill based on multi-objective planning as described in any one of claims 1 to 6 are implemented.

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