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CN-122018599-A - Temperature partition regulation and control method and system for automobile double-door-ring hot-pressing mold

CN122018599ACN 122018599 ACN122018599 ACN 122018599ACN-122018599-A

Abstract

The invention belongs to the technical field of temperature control, and relates to a temperature partition regulation and control method and system of an automobile double-door-ring hot-pressing die. The method comprises the steps of synchronously obtaining multi-mode working condition data of a hot-pressing die in a pressure maintaining stage, carrying out smooth denoising and numerical mapping processing to obtain a real-time working condition state vector, calculating phase change activity characteristics and dynamic thermal coupling characteristics for measuring the joint influence of physical interface thermal resistance and phase change latent heat by combining a thermodynamic change rule of a material, introducing the dynamic thermal coupling characteristics into a time correlation kernel function of a nonlinear regression prediction model, predicting a nonlinear temperature evolution track of a target area in a future control period, and adding thermal stress punishment constraint aiming at space temperature difference in a cost evaluation process of control optimizing so as to output a cooling waterway control instruction with minimum global cost. The method improves the prediction precision of the temperature track in the processing process of the double-door ring part, and effectively avoids the cracking of the part.

Inventors

  • WANG CHUNYUAN
  • LIN WANYI

Assignees

  • 勋龙智造精密应用材料（苏州）股份有限公司

Dates

Publication Date
20260512
Application Date
20260413

Claims (10)

  1. 1. The temperature partition regulation and control method of the automobile double-door ring hot-pressing die is characterized by comprising the following steps of: Synchronously acquiring multi-mode working condition data of the hot-pressing die in a pressure maintaining stage, and carrying out smooth denoising and numerical mapping treatment on the multi-mode working condition data to obtain a real-time working condition state vector at the current moment; According to the temperature and pressure states reflected by the real-time working condition state vector and the thermodynamic change rule of the material, calculating the phase change activity characteristic for representing the martensitic transformation degree of the material and the dynamic thermal coupling characteristic for measuring the joint influence of the thermal resistance and the phase change latent heat of the physical interface; Introducing the dynamic thermal coupling characteristic into a time correlation kernel function of a nonlinear regression prediction model, and predicting nonlinear temperature evolution tracks of a target thick material region and an adjacent thin material region in a future control period by combining a historical working condition state vector and the current real-time working condition state vector; and according to the nonlinear temperature evolution track and the phase change activity characteristic, adding thermal stress punishment constraint aiming at space temperature difference in the cost evaluation process of control optimizing, and searching and outputting a cooling waterway control instruction with minimum global cost.
  2. 2. The method for controlling the temperature partition of the automobile double-door ring hot-pressing mold according to claim 1, wherein the calculation formula of the phase change activity characteristic is as follows: In the formula, Representing at a time node Is characterized by a phase change activity of (a), Representing at a time node Is used for controlling the temperature of the secondary surface of the die in real time, Indicating the inherent martensitic transformation onset temperature of the material, Indicating a predetermined phase transition temperature window constant.
  3. 3. The method for controlling the temperature partition of the automobile double-door ring hot-pressing mold according to claim 2, wherein the calculation formula of the dynamic thermal coupling characteristic is as follows: In the formula, Representing at a time node Is characterized by a dynamic thermal coupling characteristic of (a), Representing at a time node The real-time contact pressure is obtained and the contact pressure is obtained, Represents the standard rated packing pressure constant, And Representing a first weight coefficient and a second weight coefficient, respectively.
  4. 4. The method for controlling the temperature partition of the automobile double door ring hot pressing mold according to claim 3, wherein the calculation formula of the time correlation kernel function is as follows: In the formula, Representing at a time node And time node The covariance kernel function value between the two, A signal variance parameter is represented and, Representing the time-length scale parameter of the device, And (3) with Respectively at the time nodes And the time node And calculating the dynamic thermal coupling characteristics.
  5. 5. The method for controlling the temperature partition of the automotive double-door ring hot-pressing mold according to claim 1, wherein the adding of the thermal stress penalty constraint for the space temperature difference in the cost evaluation process of the control optimization comprises: calculating absolute values of predicted temperature difference values of the target thick material region and the adjacent thin material region under each predicted step length; The absolute value is compared with the product of the physical Euclidean distance between the target thick material region and the adjacent thin material region and the reference safe temperature gradient; After the square of the ratio is obtained, multiplying the sum of phase change activity characteristics of the target thick material region and the adjacent thin material region and a punishment weight constant; and accumulating the calculation results of all the prediction step sizes to obtain a cross-region thermal stress penalty term, and taking the cross-region thermal stress penalty term as the thermal stress penalty constraint for the space temperature difference.
  6. 6. The method for controlling the temperature partition of the automobile double-door ring hot-pressing mold according to claim 1, wherein the multi-mode working condition data comprises real-time flow corresponding to the secondary surface temperature, the local contact pressure, the cooling liquid inlet temperature, the cooling liquid outlet temperature and the current valve opening.
  7. 7. The method for controlling the temperature partition of the automobile double-door ring hot-pressing mold according to claim 6, wherein electromagnetic interference noise is eliminated through a moving average filtering algorithm in the process of carrying out smooth denoising and numerical mapping processing on multi-mode working condition data, and linear normalization processing is carried out on the flow data and the pressure data so as to construct a real-time working condition state vector at the current moment.
  8. 8. The method for controlling and controlling the temperature partition of the automobile double-door ring hot-pressing mold according to claim 1, wherein the cooling water path control command comprises a valve opening control sequence generated under given valve maximum opening constraint and flow upper limit constraint through a quadratic programming solving algorithm.
  9. 9. The method for controlling the temperature partition of the automobile double-door ring hot-pressing mold according to claim 8, wherein the first control command of the valve opening control sequence is extracted and converted into an electric pulse signal, and the electric pulse signal is output to a proportional-integral regulating water valve of a corresponding partition to execute dynamic distribution of a cooling water channel.
  10. 10. A temperature partition regulation and control system of an automobile double door ring hot-pressing mold, characterized by comprising a processor and a memory storing computer instructions, wherein the processor realizes the temperature partition regulation and control method of the automobile double door ring hot-pressing mold according to any one of claims 1 to 9 when executing the computer instructions.

Description

Temperature partition regulation and control method and system for automobile double-door-ring hot-pressing mold Technical Field The invention belongs to the technical field of temperature control, and particularly relates to a temperature partition regulation and control method and system of an automobile double-door-ring hot-pressing die. Background In modern automobile manufacturing processes, double door ring parts are usually spliced into a whole by a laser splice welding technology, wherein the plates with different thicknesses and different strengths are spliced into a whole. After the splice welding plate is heated to austenitizing temperature, the splice welding plate needs to be quickly transferred into a hot pressing die to be subjected to stamping forming and die closing pressure maintaining cooling. In the pressure-keeping cooling stage, austenite-to-martensite phase transformation occurs in the material, so that the part obtains the physical characteristics of ultra-high strength. In this complex process link, accurate mold internal temperature field control has a decisive influence on guaranteeing the yield strength and dimensional accuracy of the final structural member. Currently, for temperature control of hot press dies, an independent proportional-integral-derivative control algorithm or a basic model predictive control algorithm is generally adopted in the mainstream scheme in the industry. The conventional schemes mainly rely on thermocouples arranged in the hot-pressing die, feedback is directly carried out according to static deviation between real-time temperature acquired by a sensor and target temperature set by a process, and control signals are calculated and output, so that the valve opening of each partition cooling waterway is regulated, and independent cooling targets of each area are expected to be realized. However, the automobile double-door ring part has a special structure with adjacent different material thicknesses, and severe latent heat release of phase change is accompanied in the cooling process, so that the actual engineering scene is extremely complicated. In the closed die pressure-maintaining cooling stage, when the thick plate material region is rapidly cooled and the martensitic transformation is triggered, huge transformation latent heat can be released in the material in a short time. At the same time, the volume expansion caused by the reconstruction of the metal lattice can lead to a sudden increase in the local contact pressure between the plate and the mould. The micromechanics change to cause the high nonlinear mutation of the physical interface contact thermal resistance between the die and the plate, the abrupt attenuation of the dynamic contact thermal resistance and the concentrated release of huge amount of phase change latent heat generate physical superposition, the interface thermal resistance is taken as the serious distortion of the existing prediction model of the static constant, and the waterway valve opening calculated by the control algorithm is seriously mismatched with the actual heat leading-out requirement. The foregoing control mismatch often results in a cooling rate of the thick material region not reaching the standard, or excessive cooling is performed by the long-term fully-open water valve in order to forcibly depress the temperature of the thick material region, and excessive cooling capacity can generate transverse heat conduction through the metal matrix of the mold, seriously interfere with the adjacent thin material region, and cause unexpected rapid cooling of the thin material region. Such cross-zoned thermal conduction cross-interference can induce extremely steep spatial temperature gradients at thick-thin material junctions. Under the conditions that the material is in a phase transition period and is in a brittle sensitive state, huge space thermal stress difference can directly cause the shrinkage of a thin material region to be too fast, the whole deformation balance of the part is broken, and finally serious local shrinkage and warpage of the part are induced, even the welding seam at the junction of thick and thin materials is directly caused to crack, so that the molding yield of the double-door-ring part is restricted. Disclosure of Invention The invention aims to provide a temperature partition regulation and control method and a temperature partition regulation and control system for an automobile double-door-ring hot-pressing die, which are used for solving the technical problems of temperature evolution prediction distortion caused by superposition of dynamic thermal resistance mutation and latent heat release of phase change under a complex engineering scene of double-door-rings, and further causing shrinkage warping at thick and thin junctions and weld cracking. In order to solve the problems, the technical scheme of the temperature partition regulation and control method of the automobile double door r