YU Yu-zhen
,
REN Xin-yi
,
DU Feng-shan
,
SHI Jun-jie
钢铁研究学报(英文版)
In view of characteristics of particle swarm optimization (PSO) algorithm of fast convergence but easily falling into local optimum value, a novel improved particle swarm optimization algorithm is put forward, and it is applicable to identify parameters of hydraulic pressure system model in strip rolling process. In order to maintain population diversity and enhance global optimization capability, the algorithm is firstly improved by means of decreasing its inertia weight linearly from the maximum to the minimum and then combined with chaotic characteristics of ergodicity, randomness and sensitivity to initial value. When the improved algorithm is used to identify parameters of hydraulic pressure system, the comparison of simulation curves and measured curves indicates that the identification results are reliable and close to actual situation. A new method was provided for hydraulic AGC system model identification.
关键词:
hydraulic pressing system
,
PSO algorithm
,
chaos
,
self-adaptive
,
parameter identification
REN Xin-yi
,
DU Feng-shan
,
HUANG Hua-gui
,
ZHANG Shang-bin
钢铁研究学报(英文版)
Based on the hydraulic bending control system, the electrohydraulic servo pressure control simulation model is built. Taking into account of the inadequacy of P-type immune feedback controller, an improved fuzzy immune PID controller is put forward. Drawing on immune feedback principle of biological immune system, the P-type immune feedback controller is connected with conventional PID controller in series and then in parallel with design fuzzy immune PID controller. The controller parameters can be adjusted on line by the rules of immune feedback controller and fuzzy controller. In order to gain the optimal parameters of the controller, the parameters of the controller are off-line optimized by the best multiple optimal model PSO algorithm. The simulation results indicate that the method has characteristics of small overshoot, short adjusting time and strong anti-interference ability and robustness. The quality of the strip shape can be further improved.
关键词:
electrohydraulic bending system
,
immune feedback control
,
fuzzy control
,
PSO algorithm
,
strip shape
DU Feng-shan
,
WANG Gui-guo
,
et al
钢铁研究学报(英文版)
To improve the accuracy and speed of finite element calculation, a new friction model is proposed with a layer of thin friction element being introduced between the roller and workpiece to consider the contact friction. This model is used in the three-dimensional elastic-plastic finite element model of strip rolling process. With the consideration of the geometry size and physical characteristics of intermediate medium between roller and workpiece, this stiffness of the friction element is corrected by two factors (the thickness of friction element and β factor). Without any assumption about the value and direction of friction force and neutral point position, the rolling processes is simulated using this model. The results obtained by this model have been compared with experimental results to verify the feasibility of the model. The model is of great important to the research of the friction model in the strip rolling process, and can be extended to all press-working process.
关键词:
contact friction;FEM;rolling;friction element
YU Hui
,
DU Feng-shan
,
XU Zhi-qiang
钢铁研究学报(英文版)
Roller pass is one of the key factors affecting the product quality in the retained mandrel rolling process. The metal flow condition of rolling deformation area was researched using the FEA (finite element analysis) software Marc. The influences of the pass bottom radius, the sidewall radius, the sidewall angle, the roller shoulder fillet radius, as well as the roller gap on the rolling process under the conditions of different friction were discussed. Based on these results, the changes of the workpiece exit width, the mandrel axial force, the rolling force, and the rolling torque associated with various parameters were determined, which would provide the basis for designing the pass and determining the rolling condition reasonably.
关键词:
finite element analysis
