布谷鸟搜索耦合遗传算法的电液伺服系统模型预测控制设计

由于电液伺服系统的非线性导致PID控制难以对系统模型进行良好的预测控制,构建了由液压伺服阀和液压缸组成的电液伺服系统模型,并利用布谷鸟搜索算法(CSA)和遗传算法(GA)实现对电液伺服系统的模型预测控制(MPC)。依据连续状态空间模型建立了力识别模型,对液压缸和黑箱进行了数学建模。采用CSA和GA算法对MPC控制进行优化和参数整定,提高系统模型的稳定性和控制性能。对系统模型的外力、电压和振幅信号进行仿真实验,并与PID控制进行比较。结果表明:相比于PID控制,利用CSA和GA的MPC控制下外力的超调量降低了20%,电压的波动误差降低了1.5 V,振幅的跟踪稳态误差降低了50%。说明采用CSA和GA的MPC控制方法,提高了电液伺服系统的鲁棒性和稳定性,具有较高的跟踪精度并提升了系统的动态性能。     

基于综合加权因子的结晶器预测解耦控制

针对结晶器系统耦合控制问题,提出了一种基于综合加权因子的结晶器非线性预测控制策略。针对基于混沌粒子群优化的非线性预测控制算法(CPSO-NPC),对预测误差进行单目标优化的不足之处,提出了多目标优化的CPSO-NPC算法。同时,将多目标优化思想和非线性预测输出误差权重相结合,提出了综合加权因子。综合加权因子既可以实现多目标优化,也可以消除系统内部变量之间耦合。所设计的算法被应用在结晶器的控制过程中,仿真结果证明了本文提出算法的可行性和有效性。     

电液伺服系统的参数辨识研究

基于电液伺服系统的非线性和不确定性,本文提出了用系统辨识的方法对电液伺服系统参数进行过程辨识,将系统模型的非线性影响转化为系统最小误差的控制,使非线性和不确定因素对系统的影响大大减小,从而提高了电液伺服控制系统的控制精度和鲁棒性。     

一种改进的液压伺服预测控制系统

针对常规液压伺服系统的非线性、时滞等问题，提出一种基于多目标粒子群和类圆映射的液压伺服非线性预测控制系统(QCMPSO-NPC)。利用类圆映射技术将高维目标空间映射到二维坐标平面，监控粒子种群的进化状态。为平衡档案集的收敛性和多样性，采用面积支配和扇块距离管理档案集，并且根据种群进化状态自适应选择全局最优粒子。将改进算法应用到液压伺服系统中，系统可以准确追踪设定值。仿真实验结果表明：采用QCMPSO-NPC算法保证了解集的收敛性和多样性，输出响应最快，误差最小，位置跟踪性能优于PSO-NPC算法和GPC算法，验证了基于QCMPSO-NPC算法液压伺服控制系统的有效性和可行性。     

电液位置伺服系统的模糊预测函数控制

针对电液位置伺服系统的非线性、参数时变性等突出问题,提出了一种新型模糊预测函数控制方法.它将预测函数控制和具有参数自调整的模糊控制进行综合来共同控制电液位置伺服系统,并且根据控制系统的位置偏差和偏差变化率,利用放大倍数对模糊控制器的参数进行在线修改.仿真结果表明,采用该控制方法设计的控制器满足系统对快速性和稳态精度的要求,系统具有较强的鲁棒性和抗干扰性,能够实现复杂系统的有效控制.     

泵控缸电液位置伺服系统的神经网络模型参考自适应控制

针对泵控缸电液位置伺服系统的跟踪控制问题,提出了神经网络模型参考自适应控制方法.泵控缸电液位置伺服系统由于其自身特性以及外界干扰因素的影响存在严重的非线性,因此,很难采用传统的控制方法来控制.为此,首先利用GA-BP算法离线辨识伺服系统的神经网络模型,得到网络参数的初值,然后利用改进的BP算法在线对网络参数进行微调,以得到较为准确的网络预测输出,从而为在线神经网络控制提供较准确的梯度信息.仿真结果表明,该方法能保证系统具有较快的响应速度和较高的控制精度,并具有较好的自适应性和鲁棒性.     

电液伺服系统动态特性的研究现状与展望

综述了近来年电液伺服系统动态特性的研究成果及现状,并对其发展趋势进行了分析与展望。提出将现代非线性振动理论引入电液伺服系统,应用非线性动力学的理论揭示伺服系统动态过程的本质和机制,对系统进行状态监测和智能故障诊断,具有十分重大的意义,在科学与工程中具有广阔的应用前景。     

基于李雅普诺夫理论的电液伺服系统非线性位置控制研究

电液伺服系统存在高度非线性及参数时变等问题,同时由于其多学科性质导致精确模型的建立比较困难。针对电液伺服系统非线性位置控制问题,采用基于非线性系统的李雅普诺夫理论的控制器实现电液伺服系统的有效控制,并对控制效果进行仿真验证。构造了伺服阀以及液压执行器的动力学方程,建立电液伺服系统简化数学模型。基于非线性系统的李雅普诺夫理论,利用积分反演法设计了电液伺服系统控制器。采用MATLAB软件对电液伺服系统进行仿真,并与传统PID控制器的计算结果进行对比和分析。仿真结果显示:采用所设计的控制器,电液伺服系统对阶跃和正弦信号的跟踪性能较优,所需控制电压减少50%左右,跟踪误差也大大减少。     

电液伺服系统的完整建模及变尺度多调整因子解析模糊控制

从考虑电液伺服系统的非线性和参数的时变性出发,建立了电液伺服系统的完整模型。并采用了一种改进的变尺度多调整因子模糊控制器控制。仿真结果表明此控制方法能有效控制此时变电液伺服系统模型。     

非线性电液位置伺服系统的自学习滑模模糊控制

针对电液伺服系统存在参数变化、负载干扰等非线性因素，且难以建立精确的数学模型用于实时控制的特点，将一种自学习滑模模糊控制方法应用于电液伺服系统，并将滑模控制策略应用于模糊控制中，建立以滑模函数值为输入、伺服阀控制电压为输出、模糊规则只有11个的简单模糊控制器，通过在线学习调整模糊规则使系统状态快速滑向状态平衡点。该控制方法结合了滑模控制和自适应模糊控制，鲁棒性强、结构简单。仿真和实时控制结果表明：在电液位置伺服系统中取得良好的控制精度和稳定性。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.