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81.
针对一类由局部状态空间(LSS)Fornasini-Marchesini(FM)第二模型描述的,具有时变状态滞后的2-D离散系统,其中时变滞后项的上、下界均为正实数,研究了其稳定性和控制综合问题。首先,利用Lyapunov-Krasovski泛函方法,提出了系统的稳定性准则。再根据这一准则,分别设计状态反馈和动态输出反馈控制器保证系统的稳定性。状态反馈控制律和输出反馈矩阵可由线性矩阵不等式(LMI)求得。最后,通过数值算例说明所得结果的有效性。 相似文献
82.
The output feedback stabilization is considered for a class of nonlinear time-delay systems with inverse dynamics in this paper.An appropriate state observer is constructed for the unmeasurable system states in order to realize the control objective.By adopting the backstepping and Lyapunov-Krasovskii functional methods,a systematic design procedure for a memoryless output feedback control law is presented.It is shown that the designed controller can make the closed-loop system globally asymptotically stable while keeping all signals bounded.An illustrative example is discussed to show the effectiveness of the proposed control strategy. 相似文献
83.
In this study, Adaptive Neuro-Fuzzy Inference System (ANFIS) has been used to model local scouring depth and pattern scouring around concave and convex arch shaped circular bed sills. The experimental part of this research study includes seven sets of laboratory test cases which were performed in an experimental flume under different flow conditions. A data set consists of 2754 data points of scouring depth were collected to use in the ANFIS model. The ratio of arch diameter, D, to flume width, W, is used as a non dimensional variables in all test cases. The results from ANFIS model were compared with the results of ANN model obtained by Homayoon et al. [24] and previously presented models. The results indicated that for D/W equal to 1 and 1.2, the ANFIS models produced a good performance for convex and concave bed sills. As a result, the ANFIS models can be used as an alternative to ANN for estimation of scour depth and scour pattern around a concave bed sill installed with a bridge pier. 相似文献
84.
An inductively coupled (ic) radio-frequency (rf) stabilized argon plasma was generated in a quartz tube using a 7 MHzrf generator. The electrical and thermal powers were measured and the efficiency of energy conversion was computed. The results
indicate that for a constant power input, there is an optimum argon flow rate for which maximum energy conversion efficiency
occurs. 相似文献
85.
86.
对于复杂微细、错边量小的激光焊接拼缝测量,现有的视觉传感器方法不能稳定、可靠地提取出拼缝的中心位置、拼缝宽度等信息。为此,提出了基于微景深的激光焊接对接拼缝测量方法,该方法采用高倍光学放大镜头、工业CCD(Charge Coupled Device)/CMOS(Complementary Metal-Oxide-Semiconductor Transistor)相机和LED(Light-Emitting Diode)外部照明装置,以光学成像光轴与被测表面法矢呈45°的方式,组成的对接拼缝的非接触测量系统,既解决了显微放大时景深很小、测量范围小的问题,又解决了狭窄拼缝高光学放大倍数拼缝检测的难题。实验结果表明,该系统可快速准确地提取出拼缝中心坐标、拼缝宽度以及拼缝局部表面法矢。拼缝宽度测量精度优于5 μm,拼缝中心测量精度优于6 μm,可识别的最小拼缝宽度为0.02 mm,完全满足激光焊接对接狭窄拼缝的检测与自动跟踪的要求。 相似文献
87.
为恢复雾天图像对比度和颜色,更好地提取图像中的信息,根据海上开阔海域的特点,利用3维到2维透视投影模型,推导了海上图像任意像素点景深的计算公式,并结合暗原色先验知识,有效解决基准景深点的选取和天空亮度的选取问题,最后基于相对景深模型和大气散射模型,对单幅雾天图像进行清晰化处理。通过大量雾天降质图像的实验验证,该算法的去雾效果优于基于暗原色先验统计方法的效果。 相似文献
88.
在X2001应力分析仪上采用悬臂梁加载法测试了可以用于铍的X射线应力测试的5个衍射晶面的应力常数。结果表明,铍的5个衍射晶面的应力常数差异较大,在进行X射线应力分析时.应采用相应衍射晶面的应力常数,才能获得准确的应力分析结果。由于X射线对铍有较大的穿透深度,必须考虑X射线穿透深度对应力常数标定的影响。 相似文献
89.
90.
V.V. Pani? V.M. Jovanovi? M.W. Barsoum A.B. Dekanski 《Surface & coatings technology》2007,202(2):319-324
Electroactive oxide coatings on titanium, known in industrial chlorine production as dimensionally stable anodes (DSA), are of limited service life owing to the dissolution of active oxide, but also due to low corrosion stability of titanium, at high anodic potentials and elevated temperatures. In order to improve the anode stability, ternary carbide, Ti3SiC2, could be a promising material for the coating support, since chemical corrosion stability of Ti3SiC2 is significantly higher if compared to Ti. In this work, the possibility of the sol-gel preparation of RuO2-TiO2 coating on Ti3SiC2 is investigated and comparison of the basic characteristics of sol-gel processed oxide coating, Ru0.5Ti0.5O2, applied onto Ti3SiC2 and Ti, is reported. Microscopic investigation of the coating surface showed that considerably less cracked coating is formed onto the Ti3SiC2 support. Slightly higher voltammetric currents are registered for Ti3SiC2-supported coating in H2SO4 and NaCl solution. The activity for chlorine evolution is higher, while the currents of oxygen evolution reaction are lower for Ru0.5Ti0.5O2/Ti3SiC2 anode in comparison to Ru0.5Ti0.5O2/Ti anode. Even though these preliminary results on the basic electrochemical properties of Ru0.5Ti0.5O2/Ti3SiC2 anode and chemical stability of Ti3SiC2 are promising, the accelerated stability test in NaCl solution showed that coated Ti3SiC2 is not anodically stable and lasts considerably shorter than Ru0.5Ti0.5O2/Ti anode prepared and tested under the same conditions. 相似文献