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991.
This paper presents a two-dimensional (2D)-based approach to the problem of output feedback repetitive control for uncertain
discrete-time systems. It is shown first how the proposed repetitive control scheme can be equivalently formulated in the
form of a distinct class of 2D system. Then sufficient conditions for the existence of output feedback control law are derived
in terms of linear matrix inequality (LMI), and the control law matrices are characterized by the feasible solutions to this
LMI. Moreover, an optimization problem is introduced to efficiently solve the optimal output feedback control law by minimizing
the upper bound of a given cost function. Compared with the commonly used 1D-based method, the proposed approach increases
the degree of freedom of controller design by not only including in the scheme an output feedback gain but also a feed forward
one which can be simultaneously solved using the 2D-based procedures presented in the paper. Finally, a numerical example
is provided to demonstrate the effectiveness of the proposed method. 相似文献
992.
Ho-Chan Kim Hardian Reza Dharmayanda Taesam Kang Agus Budiyono Gigun Lee Widyawardana Adiprawita 《International Journal of Control, Automation and Systems》2012,10(1):88-101
Rigorous control synthesis for an unmanned aerial vehicle necessitates the availability of a good, reasonable model for such
a vehicle. The work reported in this paper focuses on the modeling of a rotary unmanned aerial vehicle (RUAV) and the development
of a robust controller that can handle parameter uncertainties and disturbances. The parameters of the plant model are obtained
through the use of the prediction error method with real flight data. The response of the identified linear model shows a
good match with the measured flight data. The H
∞ control scheme is applied to obtain a robustly stable controller using the identified model. The proposed controller is analyzed
using frequency-domain analysis and time-domain simulations. The performance of the proposed H
∞ controller is better than that of the conventional proportional derivative controller in that the proposed controller has
a shorter settling time and less overshoot. Furthermore, the degradation of the proposed controller performance is negligible
and stability is maintained when the input gains to the plant are doubled, which demonstrates the good performance and robustness
of the controller. 相似文献
993.
An investigation into vehicle rollover prevention by coordinated control of active anti-roll bar and electronic stability program 总被引:1,自引:0,他引:1
Seongjin Yim Kwangki Jeon Kyongsu Yi 《International Journal of Control, Automation and Systems》2012,10(2):275-287
This paper presents a method for designing a controller that uses an active anti-roll bar (AARB) and an electronic stability program (ESP) for rollover prevention. ESP with longitudinal speed control (LSC) can carry out active braking to reduce vehicle speed and lateral acceleration to prevent a rollover. To enhance the rollover prevention capability of the ESP, an AARB is adopted. The controller for the AARB was designed based on linear quadratic (LQ) static output feedback (SOF) control methodology, which attenuates the effect of lateral acceleration on the roll angle and roll rate by control of the suspension stroke and the tire deflection of the vehicle. Although this AARB significantly increases ride comfort and rollover prevention, it has a drawback — the vehicle loses its maneuverability. Therefore, the ESP with LSC is used to overcome this drawback. Simulations showed that the proposed method was effective in preventing a rollover. 相似文献
994.
Commercial Nicalon fibres were prepared by thin transverse sectioning and studied by transmission electron microscopy. A progressive tilting of the incident beam allows us to explore the selected-area diffraction (SAD) pattern along two orthogonal directions, increasing the tilting angle (dark-field (DF) imaging). The lattice fringes technique was also used. The samples were Nicalon 001, 101 and 201 fibres, the latter also being studied after heat treatment in air at 1300° C for 48 h. The SAD pattern of the 001 fibre only shows the SiC, 1 1 intense halo whereas the other samples show all the SiC (1 1 1, 2 2 0 and 31 1) strongly scattered beams, indicating a microcrystalline state. Correspondingly, DF imaging does not indicate any localized measurable scattering domain for 001. Only bright dots can be seen, less than 1 nm in size. The other fibres show SiC microcrystals respectively 2 nm (1 01 ), 3 nm (201 ) and up to 7 nm (heat-treated 201) in extent. Free aromatic carbon, shaped in small units less than 1 nm in size fills up the interstices between SiC. These units tend to lie flat on SiC. In heat-treated fibres, they form incomplete layers around the edges. In addition, the heat-treated 2 01 fibre show a 1m thick layer of cristobalite at the fibre surface. These crystals are polytypes. 相似文献
995.
Bruno Gabel Denis Thiéry Vaclav Suchy Frédéric Marion-Poll Peter Hradsky Pavel Farkas 《Journal of chemical ecology》1992,18(5):693-701
The European grapevine moth (EGVM),Lobesia botrana, is a major pest of grapes in Europe. Females are attracted to a nonhost plant: tansy (Tanacetum vulgare L.), which is a common weed in Slovakian vineyards. A steam distillate extract of tansy flowers was analyzed by means of a GC-EAG technique to screen constituents detected by the olfactory receptors of EGVM females. From more than 200 GC peaks, nine peaks corresponding to monoterpenoids released an EAG response in more than 70% of the females (N=15):p-cymene,d-limonene,-thujene,-thujone,-thujone, thujyl alcohol, terpinene-4-ol, (Z)-verbenol, and piperitone. The steam distillate of tansy as well as a synthetic blend of identified compounds released consistent attraction in a field cage. The use of nonhost plants and host plant odors in integrated pest management is discussed. 相似文献
996.
Data are presented on the influence of prophylactic vitamin administration to schoolchildren in two schools on their health. The morbidity rate significantly decreased, the levels of lysozyme in the saliva, hemoglobin in the blood and total protein in the blood serum rose in the children who received multivitamin "Undevitum" during 5-7 months, as compared to those who were not given the vitamins. Vitamin administration did not influence the physical development of schoolchildren. 相似文献
997.
M. Jiménez-Melendo J. P. Riviére T. Suzuki H. Koizumi J. Castaing A. Domínguez-Rodríguez 《Journal of Materials Science》1992,27(13):3589-3593
NiO single crystals prepared by two crystal growth techniques (zone melting in an arc-image furnace and Verneuil crystallization have been deformed by compression along 001 at temperatures as low as 4.2 K, and the dislocation substructure observed by transmission electron microscopy. The Peierls mechanism has been suggested as the mechanism controlling the mechanical behaviour at the lower temperatures. The dislocations generated at cavities found in the zone-melted crystals may be responsible for the increase of the flow stress of these crystals compared with the Verneuil ones. 相似文献
998.
In finite labelled transition systems the problems of deciding strong bisimilarity, observation equivalence and observation congruence areP-complete under many—oneNC-reducibility. As a consequence, algorithms for automated analysis of finite state systems based on bisimulation seem to be inherently sequential in the following sense: the design of anNC algorithm to solve any of these problems will require an algorithmic breakthrough, which is exceedingly hard to achieve. 相似文献
999.
C García Barroso R Cela Torrijos J A Pérez-Bustamante 《Zeitschrift für Lebensmittel-Untersuchung und -Forschung》1987,185(4):307-314
The different groups and/or classes among phenolic acids and aldehydes identified during the elaboration process of "fino" sherry wine have been studied. The study was carried out using different processes during the elaboration of the wine and we have attempted to establish whether the different treatments of the grape affect these groupings. The study was undertaken by means of cluster and multifactorial analysis on the data obtained by the quantitative determination of phenolic acids and aldehydes during vinification and in experiments carried out on the grape under different mechanical treatments. The analysis of phenolic acids and aldehydes was done with HPLC, using a C-18 mu-Bondapak and a stepwise composite gradient. The samples were previously extracted with ethylic ether. 相似文献
1000.
Jesús F. Ontiveros Bing Hong Kenji Aramaki Christel Pierlot Jean-Marie Aubry Véronique Nardello-Rataj 《Journal of surfactants and detergents》2021,24(3):401-410
A series of symmetrical dialkyl methanesulfonate amphiphiles [DiC n CHSO 3 ] m M (n = 6, 7, 8) with different counter cations (Mm+ = H+, Li+, Na+, K+, Cu2+, Zn2+, Mg2+, Ca2+, Sc3+) were synthesized in five steps. Their solubility and critical micelle concentration (CMC) in water were determined highlighting a huge effect of the chain length and the nature of the cation. The hydrophilic–lipophilic balance of the surfactants were assessed with the phase inversion temperature (PIT)-slope method based on the deviation from the PIT of the reference C10E4/n-octane/0.01 M NaCl(aq) emulsion through addition of increasing amounts of the dialkyl methanesulfonates. The hydrophilicity of the surfactants was thus ranked in terms of dPIT/dxsulfonate. A “cation” scan with the [DiC 6 CHSO 3 ] m M /benzene/water systems at fw = 0.5 was finally performed confirming the hydrophilicity ranking obtained with the PIT-slope method. It revealed that the [DiC 6 CHSO 3 ] 2 Mg behaves as a “Balanced Surfactant” able to form spontaneously a three-phase microemulsion system (Winsor III) just in the presence of water and oil, in the same way as the catalytic surfactant dimethyldioctylammonium molybdate, which has the same PIT-slope. 相似文献