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1.
Forward displacement solutions are presented for a class of spatial parallel manipulators. In particular, considered are manipulators consisting of a platform supported through passive spherical joints by three branches, each branch having three-revolute joints forming its main arm. Solutions are described for arbitrary main-arm layouts and for all possible cases of redundant (nine, eight, and seven sensors) and non-redundant (six sensors) sensing of branch main-arm joint displacements. It is demonstrated that closed-form forward displacement solutions can be found for all cases of redundant sensing. Furthermore, it is shown that a closed-form solution can be obtained for one of the two possible cases of non-redundant sensing of the main-arm joint displacements. The only case of joint displacement sensing not allowing a closed-form forward displacement solution is two joints sensed per branch, a case that can be expressed as a 16th-order polynomial of a single variable. Due to the importance of having efficient and failure-safe solutions for the forward displacement problem, it is suggested that appropriate redundancy in displacement sensing should be an important consideration in the design of parallel manipulation devices. © 1994 John Wiley & Sons, Inc. 相似文献
2.
B Brismar JE Akerlund S Sj?stedt C Johansson A T?rnqvist B B?ckstrand H B?ng L And?ker PO Gustafsson N Darle M Anger?s A Falk G Tunevall B Kasholm-Tengve T Skau PO Nystr?m T Gasslander A Hagelb?ck B Olsson-Liljequist AE Eklund CE Nord 《Canadian Metallurgical Quarterly》1996,28(5):507-512
The objective of this study is to describe usual medical management and costs associated with recurrent respiratory infections in subjects with chronic obstructive bronchitis in France. A prospective survey was performed in Autumn 1994 on a national sample of private practice pulmonologists (N = 71). Two hundred forty-four patients, presenting at least one infection of the lower respiratory tract, were included. Bronchitis was the most frequent acute exacerbation observed (94%). Pneumonia concerned 9% of the patients. Biological tests, X-rays and pulmonary function tests were prescribed for, respectively, 59, 65 and 45% of the patients. Following the visit, 15 patients were hospitalized (6%). The direct medical cost per acute exacerbation was estimated 3,289 francs (1994 value) of which 60% were hospital-related. An average 10.4 day sick-leave was prescribed to 21% of patients in employment. For those patients, this sick-leave was associated to an extra-cost of 1,264-1,876 francs for Social Security and of 0-2,553 francs out of pocket per episode varying according to their Benefit Regimen. 相似文献
3.
F Tárkányi F Szelecsényi P Kopecky T Molnár L Andó P Mikecz GY Tóth A Rydl 《Canadian Metallurgical Quarterly》1994,45(2):239-249
Proton induced nuclear reactions on enriched 111Cd and 112Cd have been studied up to 30 MeV in the context of routine production of the medically used isotope 111In with low and medium energy cyclotrons. The excitation functions of 111Cd(p,n)111m,gIn and 112Cd(p,2n)111m,gIn as production reactions and 111Cd(p,2n)110mIn, 111Cd(p,2n)110In, 111Cd(p,3n)109ml,m2,In, 112Cd(p,3n)110mIn, 112Cd(p,3n)110gIn as competing processes have been measured using the activation method involving the stacked-foil technique. The deduced thick target yields are compared with those obtained experimentally. 相似文献
4.
论述了以国产克百威代替进口75%呋喃丹母粉加工3%颗粒剂的技术改进;并通过产品质量、药效、毒理、残留、环保诸方面的对比,证明改进后的工艺技术是成功的,具有独创性,为以产顶进,节汇创汇,闯出了一条新路子。 相似文献
5.
乙酸乙酯合成实验的方法、产品产率计算几种情况的分析讨论。 相似文献
6.
7.
Basil Mohammed Al-Hadithi Antonio Javier Barragán José Manuel Andújar Agustín Jiménez 《Applied Soft Computing》2013,13(12):4802-4812
In this paper, a fuzzy based Variable Structure Control (VSC) with guaranteed stability is presented. The main objective is to obtain an improved performance of highly non-linear unstable systems. The main contribution of this work is that, firstly, new functions for chattering reduction and error convergence without sacrificing invariant properties are proposed, which is considered the main drawback of the VSC control. Secondly, the global stability of the controlled system is guaranteed.The well known weighting parameters approach, is used in this paper to optimize local and global approximation and modeling capability of T-S fuzzy model.A one link robot is chosen as a nonlinear unstable system to evaluate the robustness, effectiveness and remarkable performance of optimization approach and the high accuracy obtained in approximating nonlinear systems in comparison with the original T-S model. Simulation results indicate the potential and generality of the algorithm. The application of the proposed FLC-VSC shows that both alleviation of chattering and robust performance are achieved with the proposed FLC-VSC controller. The effectiveness of the proposed controller is proven infront of disturbances and noise effects. 相似文献
8.
基于MATLAB的小波包信号消噪处理 总被引:2,自引:0,他引:2
信噪分离是小波包应用于信号分析的一个重要方面。本文在基于MATLAB的基础上,采用小波包对含高斯白噪声信号进行分解,通过不同的量化阈值对小波包系数进行处理、重构得出小波包消噪后的信号。计算机仿真结果表明,用不同量化阈值的小波包可对含高斯白声信号进行消噪重构。 相似文献
9.
SNMPv3在网络安全管理系统中的应用 总被引:2,自引:0,他引:2
本文介绍了网络安全管理系统和简单网络管理协议SNMP的概念,并对系统的框架结构进行了深入研究,最后重点阐述了安全管理系统中SNMPv3的设计实现。 相似文献
10.
计算机取证有效打击计算机犯罪 总被引:11,自引:0,他引:11
计算机取证研究的是如何为调查计算机犯罪提供彻底、有效和安全的技术,其关键是确保证据的真实性、可靠性、完整性和符合法律规定。本文首先分析计算机取证的产生背景,重点介绍计算机取证的原则和取证的步骤,进一步阐述计算机取证所采用的技术以及国内外在计算机取证领域研究的进展。 相似文献