DSP+FPGA数据处理系统的研究与应用

针对铣削加工中心主轴刚度检测系统实时性的要求,重点阐述了DSP FPGA的数字硬件系统和流水线结构的CORDIC算法在FPGA中的实现,并通过仿真和实验对CORDIC算法的理论值和计算数值进行对比分析,结果表明,计算数值非常接近理论值.     

美国流体动力工程研究中心简介

本文简要介绍了美国国家流体动力工程中心的基本情况、研究方向和教学计划.在此基础上对我国流体动力传动与控制的科研单位和企业的发展提出了一些看法.     

增量式旋转轴定向的应用实例

绝对值编码器能够准确地保持坐标位置,因此在需要定位或定向时常选用这种编码器.但某些时候由于改造的机械或者资金情况的限制只能使用增量式编码器,文中旨在讨论在这种情况下如何实现旋转轴的定向和定位.     

船舶ERP选型:集成性是关键

当前,信息化已经渗透到世界船舶工业的设计、生产、管理、服务等方方面面,其应用的深度与广度决定了行业综合水平的高低,成为大至一个国家的船舶工业、小至一个船舶企业能否在市场中生存和发展的关键.当造船业已经普遍意识到,以"信息化推动造船现代化"是中国造船工业追赶国际先进水平的最后机遇时,造船业的生存发展与IT厂商的策略几乎在同一时间不谋而合,在造船业竞争的搏奕中厂商的相助少不了.     

匈牙利农业机械化发展情况特点

匈牙利一向是一个重农国家,它位于欧洲中部的喀尔巴阡山盆地.全国地势低洼,北部为丘陵、南部为平原,气候适宜,耕地平坦.平原约占国土面积的60%,低丘陵地和山地约占40%.农业用地586万公顷,其中可耕地450万公顷,约占国土面积的48%.匈牙利种植的农作物主要有小麦、玉米和马铃薯等,主要出口以肉类和谷类为主的农产品.     

"认知"是信息化应用的绊脚石——访中国航天时代电子公司第十六研究所、七一七一厂信息处处长徐四海

此次航空航天信息化的大型选题报道让记者有幸来到地处关中平原,沃野千里,依山傍水,是与罗马并称为世界古都的"西安"进行一线采访.经过一夜的风雨洗礼,让西安这座古城尤显清新爽朗,仿佛这场风雨是特意为迎接我们而将这座城市冲刷地如此洁净,街道两旁郁郁葱葱的热带植物让你犹如置身南方小城一般.而我们此行的第一站便是位于西安市南郊航天城的中国航天时代电子公司第十六研究所、七一七一厂(以下简称7171厂).     

清理沼气废液废渣仅用五分钟

7月25日上午,江苏省农机具开发应用中心陈新华副主任、农业部南京农机化研究所陈永生主任等5人,来到江苏涟水县与农机局有关人员一起进行沼气清渣车清渣试验.研制成功的清渣车在小李集办事处胡楼村吴国成家中现场进行沼气池清渣,一池沼气废液废渣清理完毕,仅用5分钟,省时,省工,安全,效果很好.     

走区域应用示范与技术创新服务体系新模式

东营市位于黄河入海口,是黄河三角洲的中心城市,是在石油矿区基础上建设起来的新兴工业城市.近年来,除石油工业外,石油化工、盐化工、造纸、机电、轻纺、建材及生物医药等制造业门类得到较快发展,涌现出一批实力较强的企业集团,制造业逐步在东营市经济发展中占据了重要地位.     

2007年中国机床工具行业十大新闻

1.中央和地方省市主要领导频繁视察机床行业企业,国家为数控机床产业发展创造了空前良好的发展环境 胡锦涛、吴邦国、温家宝、贾庆林、李长春等党和国家领导人以及辽宁、黑龙江、山东、江苏、云南、湖北、广东、陕西、浙江、天津、重庆等省市主要领导相继视察了机床工具厂和数控系统厂.各级领导频繁视察,为数控机床产业的发展创造了空前良好的发展环境.     

回转窑滚圈应力的测试方法研究

针对现阶段滚圈的强度分析主要依据简化模型下的有限元分析,导致不能真实反应滚圈的应力情况,且误差较大的问题.提出了通过用电测法来实测滚圈的真实应力,并了解滚圈的应力分布特性,这对于指导设计部门改进滚圈的设计,正确预测滚圈的寿命,具有重要的工程意义.     

A PID-type fuzzy controller model for machine control applications

This paper introduces a PID-like fuzzy controller model, which consists of only five fuzzy rules. Each fuzzy rule is designed to carry out a single control task. A self-learning procedure is used to determine the input scale factor for auto-tuning the system. A new performance criterion is suggested as an object function for the auto-tuning procedure. The features of this fuzzy controller, used in position control applications, are demonstrated by the simulation results of two different types of plants — a d.c. motor and an inverted pendulum.Nomenclature adjusting parameter of AIAE - C _I integral control constant in ruleR _I - C _L leading control constant in ruleR _zn andR _zp - C _P proportional control constant in ruleR _P andR _N - D _ZE domain of membership function _ZE - K _a adaptive adjusting constant ofC _L - K _H adjusting parameter for high-border of dynamic domain space - K _L adjusting parameter for low-border of dynamic domain space - P _R ramp input command - P _S step input command - S _de scaling factor for input variable de(change of error) - S _e scaling factor for input variablee(error) - S _o controller output scaling factor - U _max maximum output limit of fuzzy controller     

High-temperature tribological properties of spark-plasma-sintered Al2O3 composites containing barite-type structure sulfates

Al₂O₃–50BaSO₄–20Ag, Al₂O₃–50BaSO₄–10SiO₂, Al₂O₃–50(mass%)SrSO₄, Al₂O₃–50PbSO₄–5SiO₂, Al₂O₃–50BaSO₄ and Al₂O₃–50BaCrO₄ composites (mass%) were prepared by spark plasma sintering and their microstructure and high-temperature tribological properties were evaluated. Al₂O₃–50BaSO₄–20Ag composites (mass%) showed the lowest friction coefficients at the temperature ranging from 473 to 1073 K. Thin Ag film was observed on the wear tracks of the composites above 473 K. In addition, the friction coefficients of Al₂O₃ composites containing SrSO₄ and PbSO₄ were as low as those of Al₂O₃–BaSO₄ and Al₂O₃–BaCrO₄ composites at the temperatures up to 1073 K. The thin films formed on the wear tracks of the Al₂O₃–SrSO₄ composites were composed of Al₂O₃ and SrSO₄ phases, while the films formed on the wear tracks of the Al₂O₃–PbSO₄–SiO₂ composites consisted of Al₂O₃, PbSO₄ and SiO₂ phases.     

H∞ filtering for a class of discrete-time singular Markovian jump systems with time-varying delays

The problem of _H∞$H_{\infty }$ filtering for a class of discrete-time singular Markovian jump systems with time-varying delays is investigated in this paper. The transition probabilities under consideration are time-varying, i.e., Markovian chain is nonhomogeneous. By using the Lyapunov functional approach and reciprocally convex technique, a less conservative delay-dependent bounded real lemma is developed in terms of linear matrix inequalities. Moreover, a sufficient condition for the existence of the desired filter which guarantees the stochastic admissibility and the _H∞$H_{\infty }$ performance index of the resulting filtering error system is presented. Numerical examples are employed to show the usefulness of the proposed results.     

Magneto-transport properties of Fe-doped LSMO manganites

Magneto-transport measurements have been performed on La_0.67Sr_0.33Mn_1−xFe_xO₃ (x = 0.0, 0.05 and 0.07) manganites synthesized by solid state route. The overall nature of AC susceptibility is found to be frequency independent. With the substitution of Mn by Fe, the transport properties dramatically change suppressing the double-exchange interaction. This in turn weakens the ferromagnetism and consequently decreases the paramagnetic to ferromagnetic transition temperature (T_c). However, DC electrical resistivity of the samples show board hump at metal-insulator transition temperature (T_MI) in contrary with sharp transition at T_c and T_MI < T_c indicating decoupling of electrical and magnetic properties. Resistivity behavior of these samples can be well explained by the consideration of bond percolation model which is basically developed from effective approximation method.