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61.
基于变传动比的线控转向前轮转角控制 总被引:1,自引:0,他引:1
提出一种基于混合智能变传动比技术的前轮转角控制算法;分析了车辆转向性能和转向稳定性的影响因素,利用模糊神经网络设计以控制车辆转向性能为重点的传动比控制器,利用直线拟合方法设计以转向稳定性为重点的传动比控制器,然后应用模糊软切换技术对两传动比进行切换融合,最终得出兼顾转向性能和转向稳定性的恰当总传动比;利用该传动比直接控制前轮转角,并将控制策略进行仿真实验;实验结果表明总传动比不仅在数值范围和曲线形状上更接近理想传动比,而且将对应的峰值速度控制在110km/h左右,优于其他两个分传动比的控制效果;用该传动比控制的整车稳定性和前轮路径跟踪能力较好,可见整个控制策略的有效性。 相似文献
62.
本文以选票统计问题为例,讨论了3种查找计数方法(顺序法、二分法、插值法)在统计中的应用,提出了一种新颖的查找计数方法——一次到位法,给出了用FOXPLUS数据库语言编写的算法子程序,并比较了它们各自的特点和适用范围。 相似文献
63.
提出一种在LUV空间中基于多层次化结构Nystrm方法的自适应谱聚类算法。首先引入LUV色彩空间,避免了RGB色彩空间中色彩辨别阈对分割的影响,在纹理、边缘区域取得了更好的分割效果;其次将谱聚类算法中基于多层次化结构的方法和基于Nystrm采样的方法结合起来,有效减少了运算时间、解决了数据量较大时计算过程中内存溢出的问题;最后在K均值聚类中通过对特征间隙(eigengap)的分析,自适应地选择K值的大小,解决了自动确定聚类数目的问题。将提出的方法在LUV色彩空间中和RGB色彩空间中分别进行图像分割实验,结果表明在LUV色彩空间中取得效果更加理想。同时也将提出的算法与基于Nystrm方法的谱聚类算法(spectral clustering-Nystrm,SC-N)进行比较。实验结果表明,该算法在数据运算量、运行时间和分割结果上都优于SC-N方法。 相似文献
64.
Suk Choo Chung Chang Duck Kong Young Ha Yum 《Journal of Mechanical Science and Technology》1987,1(2):133-139
The dynamic characteristics of the Korean Yi-dynasty bell type structure, including the acoustic effects, are analyzed both theoretically and experimentally. The numerical solutions of natural frequencies and mode shape for membrane and flexural behavior are obtained by using the NASTRAN program for the finite element method with plate shell elements of triangular and quadrilateral types. Test bells, A and B types similar to the Kap-Sa bell in Kong-Ju chosen among typical Korean Yi-dynasty bells, are manufactured on different scales to the original bell. To consider the effects of the variation of the structural dimension on the dynamic response, these bells are analyzed with respect to the variation of the thickness of the wall and the bottom rim and the asymmetric Dang-Jwas. The impact method with the Fast Fourier Transform Analyzer is adopted to experimentally assess the dynamic response. Results are in good agreement with the numerical solutions. 相似文献
65.
Equivalent model of multi-type distributed generators under faults with fast-iterative calculation method based on improved PSO algorithm 下载免费PDF全文
Puyu Wang Jinyuan Song Fangyu Liang Fang Shi Xiangping Kong Guangen Xie Xiao-Ping Zhang Xinxin Gu 《电力系统保护与控制》2021,6(3):371-382
There are various types of distributed generators (DGs) with diferent grid integration strategies. The transient char?
acteristics of the fault currents provided by the DGs are diferent to those of conventional synchronous generators. In
this paper, a distribution network with multi-type DGs is investigated, including consideration of DG low-voltage ride
through (LVRT). The fault current characteristics of two typical DGs, i.e. an inverter-interfaced distributed generator
(IIDG) and a doubly-fed induction generator (DFIG), are analyzed, considering the specifc operation modes. Based on
analysis of the fault characteristics, an equivalent model of the multi-type DGs under symmetrical/asymmetrical fault
conditions is established. A fast-iterative fault calculation method for enhancing the calculation efciency while avoid?
ing local convergence is then proposed using an improved particle swarm optimization (PSO) algorithm. A simula?
tion system of the distribution network with multi-type DGs is established in PSCAD/EMTDC. The simulation results
validate the high accuracy and calculation efciency of the proposed calculation method of the fault components.
This can assist in the settings of the protection threshold. 相似文献
66.
67.
Lei Ma Hongxia Lv Haonan Yu Lingtong Kong Rongyue Zhang Xiaoyan Guo Haibo Jin Guangxiang He Xiaoyan Liu 《中国化学工程学报》2021,33(5):286-296
A series of high oil-absorption resins with low cross-linking degree were synthesized by suspension polymerization using stearyl methacrylate(SMA), 2-Ethylhexyl methacrylate(EHMA), and styrene(St) as monomers.Response surface methodology(RSM) with central composite design(CCD) was also applied to determine the optimal parameters that are mainly known to affect their synthesis. Thus, the effects of the monomer mass ratio(EHMA:SMA), the rigid monomer(St) dosage, the porous agent(acetone) dosage, and their pairwise interaction on the resin's oil-absorption capacity were analyzed, highlighting PSES-R_2 as the resin with the optimum performance. The pure oil-absorption rates of PSES-R2 for gasoline, diesel, and kerosene were 11.19 g·g~(-1),16.25 g·g~(-1), and 14.84 g·g~(-1), respectively, while the oil removal rates from oily wastewater were 98.82%,65.11%, and 99.63%, respectively. 相似文献
68.
Shu Yan Fanyong Zhang Xue Feng Jian Kong Bo Wang Jinlong Yang 《International Journal of Applied Ceramic Technology》2021,18(3):817-829
A hierarchical porous cenosphere/geopolymer composite foam (FHCs/KGP) was fabricated by the simultaneous incorporation of O2 pore from hydrogen peroxide and cenosphere filler addition. Effects of both H2O2 content and high-temperature treatment on the microstructure, porosity and strength of porous FHCs/KGP foams were investigated systematically. The obtained FHCs/KGP foams showed typical amorphous structure and desirable porosity from 65 to 82%. The composites could crystallize in situ to FHCs/leucite foams above 1000℃. Compression strength of the FHCs/leucite foams showed a maximum value of 5 ± 0.3 MPa when treated at 1000°C. The improvement of mechanical properties for the composite foams was attributed to crack deflection, fractured microspheres and the good bond between the FHCs and matrix. This study could open opportunities to employ cellular foams as alternatives in structure and filtration applications. 相似文献
69.
Dongmei Hu Jin Du Guosheng Su Zhenyun Lu Chongyan Zhang Xiangmin Kong Chonghai Xu 《International Journal of Applied Ceramic Technology》2021,18(4):1222-1234
The hardness and toughness of regenerated cemented carbides, in general, are contradictory. Therefore, it is critical to explore regenerated cemented carbides with both high hardness and high toughness. In this study, regenerated WC-8-wt% Co cemented carbide with SiC nanowhisker were prepared by low-pressure sintering. The influence of SiCw contents on the microstructure and mechanical properties of regenerated WC-8-wt% Co cemented carbide was investigated. The results indicated that the hardness, density, flexural strength, and fracture toughness of regenerated cemented carbide first increased and then decreased with the addition of SiCw. The Vickers hardness, density, flexural strength, and fracture toughness could reach 1575 HV, 14.6 g/cm3, 2204 MPa, 16.85 MPa·m1/2, respectively, with SiCw content 0.5 wt%, which were increased by 14.4%, 0.7%, 12.2%, and 17.3%, respectively, when compared with the regenerated cemented carbide without SiCw. The lowest friction coefficient and the best wear resistance could be also reached when 0.5-wt% SiCw was added. The fracture mechanism of the regenerated cemented carbide contained both transgranular and intergranular fracture through the microscopic observation of fracture surface via scanning electron microscope. 相似文献
70.
Qiu Caihao Su Yishi Yang Jingyu Chen Boyang Kong Lingti Ouyang Qiubao Zhang Di 《Metallurgical and Materials Transactions A》2022,53(4):1308-1321
Metallurgical and Materials Transactions A - Precipitates including Al3Li, Al3Zr and core–shell structured Al3Li (Al3Zr) produce significant strengthening effects in Al-Li alloys by means of... 相似文献