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为了提高目前公路交通中对车辆速度的监测手段,提出一种基于ARM(advanced RISC machines)的新型雷达测速仪,结合多普勒测速原理和信号处理的谱估计法,介绍了由毫米波多普勒收发前端和SamsungS3C2410A处理器构成的雷达测速仪的整体设计,包括其硬件结构的设计和在ARM920T内核中实现基4时间抽取的快速傅里叶变换算法(fastFouriertransform,FFT)。实验结果表明,该雷达测速仪的测速精度可达±1km/h,其优化后的FFT算法具有很高的精度和运行效率。 相似文献
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Christophe Prieur 《Mathematics of Control, Signals, and Systems (MCSS)》2001,14(2):143-172
We consider control systems for which we know two stabilizing controllers. One is globally asymptotically stabilizing, the
other one is only locally asymptotically stabilizing but for some reason we insist on using it in a neighborhood of the origin.
We look for a uniting control law being equal to the local feedback on a neighborhood of the origin, equal to the global one
outside of a larger neighborhood and being a globally stabilizing controller. We study several solutions based on continuous,
discontinuous, hybrid, time-varying controllers. One criterion of the selection of a controller is the robustness of the stability
to vanishing noise. This leads us in particular to consider a kind of generalization of Krasovskii trajectories for hybrid
systems.
Date received: November 29, 1999. Date revised: August 7, 2000. 相似文献
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Published online: 18 September 2001 相似文献
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G. C. Bussolino J. Spišiak F. Righini A. Rosso P. C. Cresto R. B. Roberts 《International Journal of Thermophysics》1993,14(3):525-539
A new dynamic technique for the measurement of thermal conductivity is being developed at IMGC. The experiment consists in bringing the specimen to high temperatures with a current pulse and in measuring the temperature profiles during the free cooling period. Different techniques can be used to extract the information on thermal conductivity from the profiles. The numerical computation of thermal conductivity from the experimental temperature profiles in absolute space is possible, but it is difficult and cumbersome because one must know and take into the account the exact position of the infinitesimal elements of the specimen in different profiles. Computations in tube-space (a fictitious space where no thermal expansion occurs) are simpler and lead to less complex numerical computations. Complementary techniques to evaluate thermal conductivity as a function of temperature or at constant temperature are presented with a discussion of advantages and disadvantages of each method. Computer simulations have tested the precision of the complex software. Numerically generated temperature profiles from known thermophysical properties have been obtained and thermal conductivity has been recomputed from the profiles. The relative difference using different computational approaches and different fitting functions is always less than 0.1%.Paper presented at the Third Workshop on Subsecond Thermophysics, September 17–18, 1992, Graz, Austria. 相似文献
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The transient regime of a multiwavelength pyrometer 总被引:2,自引:0,他引:2
The transient operation of a new multiwavelength pyrometer based on a dispersing prism and a Si photodiode array is presented. After calibration, transient tests were performed using a tungsten strip lamp, supplied by a current pulse of 0.3-s duration. Measurements were carried out with a data acquisition system consisting of a FET multiplexer, a DVM (14 bit, 100 kHz), and a buffer memory (64 kbytes). Pyrometer signals are processed off-line, and temperature vs time is displayed. With the present arrangement, temperature measurements at 20 wavelengths may be performed with 200s resolution. Faster measurements are possible with a reduced number of channels.Paper presented at the Third Workshop on Subsecond Thermophysics, September 17–18, 1992, Graz, Austria.Deceased 相似文献