基于改进PSO算法的电机控制系统PID参数优化

粒子群算法(PSO,Particle Swarm Optimization)作为一种新型的随机优化方法,其算法结构简单,鲁棒性强,在组合优化和自适应控制等领域的非线性优化中有着广泛的应用前景.为此,提出一种改进的PSO优化算法,并将该算法应用于电机控制系统的PID参数优化设计.仿真结果表明,利用改进PSO算法优化的PID参数能有效改善控制系统的性能指标.     

大型喷杆喷雾机钟摆式主被动悬架自适应鲁棒控制研究

针对大型喷雾机喷杆钟摆式主被动悬架系统存在的参数不确定性和随机干扰导致控制精度低、稳定性差的问题,对基于模型补偿的自适应鲁棒控制算法进行研究。建立了钟摆式主被动悬架的非线性动力学模型和调节机构几何方程,基于模型设计了自适应鲁棒控制器,综合悬架系统和电液位置伺服系统模型中存在的参数不确定性,同时兼顾系统未补偿的摩擦力和外部扰动等不确定非线性因素,通过理论分析和试验证明,在同时存在模型参数不确定和不确定非线性的情况下,设计的控制器可以保证系统输出跟踪控制的暂态性能和稳态精度。以单出杆液压作动器驱动的28m大型喷杆主被动悬架为例,借助建立的大型喷杆悬架半实物仿真平台进行了控制算法的试验验证,并使用Stewart六自由度运动平台模拟底盘的运动干扰,与反馈线性化控制器、鲁棒反馈控制器、PID控制器进行了试验对比,结果表明,设计的基于模型补偿的自适应鲁棒控制器最大跟踪误差0.148°,而反馈线性化控制器最大跟踪误差0.201°,鲁棒反馈控制器最大跟踪误差0.51°,PID控制器最大跟踪误差0.48°。设计的控制器在同时存在参数不确定性和扰动的情况下,使用较小的反馈增益能够保证渐进跟踪性能和稳态跟踪精度。     

珍珠鸡人工授精的研究

用电刺激采精方法 ,对 5只雄性成年珍珠鸡进行 2 5只次试验 ,皆获得精液。与按摩采精法相比 ,电刺激采精法采集的精液量 (0 .5 5 m L )显著高于按摩法 (0 .12 m L ) ,平均每次射出的精子总数 (4.2 2亿个 )比按摩采精法 (2 .4 4亿个 )显著增加 ,但精子活率和受精率无显著差异。冷冻试验结果表明 ,精子的活率为 2 0 %～ 5 0 % ,输精结果表明 ,受精率可达 6 0 %。     

8个中山杉新无性系耐盐力的水培试验研究

用水培法对8个中山杉新无性系进行不同质量分数氯化钠液处理,以相对生长量(RG)、盐害指数(SI)和相对电导率(RL)为指标,进行耐盐力评估。经聚类分析和相关性分析,结果表明:在水培条件下,不同无性系的耐盐力达0.30%~0.45%。中山杉118号具有较好的耐盐性,耐盐力为0.4%~0.45%;中山杉136号、1号、146号和149号耐盐力中等,为0.35%~0.40%;而中山杉102号,27号和24号的耐盐性较差,为0.3%~0.35%。RG与RL以及RG与SI两两均呈极显著负相关,RL和SI之间呈极显著正相关。相对生长量、盐害指数和相对电导率均可作为中山杉耐盐能力综合评价指标。     

粮油检验中如何正确使用电烘箱

电烘箱是粮油检验中一种应用较广泛的仪器，若对其使用不当，会对检验结果产生影响，甚至对人员或仪器造成损伤，详细叙述了电烘箱的使用规则及注意事项。     

小鼠2细胞胚卵裂球电融合的研究

分别用８００ｖ／ｃｍ、４０～８０μｓ的单个电脉冲；８００ｖ／ｃｍ、１６０～３２０μｓ的单个电脉冲；１０００ｖ／ｃｍ、１６０～３２０μｓ的单个电脉冲；１２００ｖ／ｃｍ、１６０～３２０μｓ的单个电脉冲；１０００ｖ／ｃｍ、１６０～３２０μｓ的２个电脉冲所获得的胚胎融合率分别为８４．６％（３３／３９），１００．０％（５９／５９），９７．４％（７４／７６），９５．１％（３９／４１），６４．７％（１１／１７）。融合胚作培养后，２细胞胚的发育率分别为１５．２％（５／３３），３９．０％（２３／５９），４７．３％（３５／７４），４３．６％（１７／３９），１８．２％（２／１１）。以１０００ｖ／ｃｍ，１６０～３２０μｓ的单个脉冲诱导注射ＬＨ３９～４３ｈ，４４～４８ｈ回收的２细胞胚，胚胎融合率分别为１００．０％（２７／２７），９６．４％（２７／２８）；发育率分别为４４．４％（１２／２７），３３．３％（９／２７）。２细胞胚卵裂球融合的适宜条件为１０００ｖ／ｃｍ和１６０～３２０μｓ的单个脉冲。     

Cytotoxic, cytoprotective and antioxidant effects of isolated phenolic compounds from fresh ginger

Twenty-nine phenolic compounds were isolated from the root bark of fresh (Yunnan) ginger and their structures fully characterized. Selected compounds were divided into structural categories and twelve compounds subjected to in-vitro assays including DPPH radical scavenging, xanthine-oxidase inhibition, monoamine oxidase inhibition, rat-brain homogenate lipid peroxidation, and rat pheochromocytoma PC12 cell and primary liver cell viability to determine their antioxidant and cytoprotective properties. Isolated compounds were also tested against nine human tumor cell lines to characterize anticancer potency. Several diarylheptanoids and epoxidic diarylheptanoids were effective DPPH radical scavengers and moderately effective at inhibiting xanthine oxidase. An enone–dione analog of 6-shogaol (compound 2) was isolated and identified to be most effective at protecting PC12 cells from H₂O₂-induced damage. Almost all tested compounds inhibited lipid peroxidation. Three compounds, 6-shogaol, 10-gingerol and an enone-diarylheptanoid analog of curcumin (compound 6) were identified to be cytotoxic in cell lines tested, with KB and HL60 cells most susceptible to 6-shogaol and the curcumin analog with IC₅₀ < 10 μM. QSAR analysis revealed cytotoxicity was related to compound lipophilicity and chemical reactivity. In conclusion, we observed distinct compounds in fresh ginger to have biological activities relevant in diseases associated with reactive oxygen species.     

智能复合控制在电液伺服系统中的应用

讨论了模糊逻辑和神经网络控制器在电液伺服位置系统中的应用,据此,提出一种智能复合控制方法,仿真和实验表明,这种控制器对系统参数变化不灵敏,且能有效地改善系统的动态特性。     

Effective working areas of the electro hydraulic power impulse

In order to ascertain the numbers of the electrodes (treatment for the sewage) and forecast the grain size property of the cracked mineral, based on the hypothesis of the equivalent effective volumes of one discharge of electro hydraulic power impulse technology, the formulas are worked out for computing the effective working areas of the two common working modes. The theoretic analysis and the results of the experiments of the treatment of bacillus coil liquid and crushing of quartz ceramic show that the results conform to the formulas relatively, and the precision of the calculated data has relations with the polluted degree of the sewage, the intensity, elasticity and dimension of the solid material, and the formulas for computing the effective working areas are feasible.