This paper presents a scheme of integrated guidance and autopilot design for homing missiles against ground fixed targets. An integrated guidance and control model in the pitch plane is formulated and further changed ...This paper presents a scheme of integrated guidance and autopilot design for homing missiles against ground fixed targets. An integrated guidance and control model in the pitch plane is formulated and further changed into a normal form by nonlinear coordinate transformation. By adopting the sliding mode control approach, an adaptive nonlinear control law of the system is designed so that the missile can hit the target accurately with a desired impact attitude angle. The stability analysis of the closed-loop system is also conducted. The numerical simulation has confirmed the usefulness of the proposed design scheme.展开更多
The grounded theory of qualitative methods was applied to researching the social integration of tourism la-bor migrants in the Jiuhua Mountain of Anhui Province, China. The research was conducted based on the in-depth...The grounded theory of qualitative methods was applied to researching the social integration of tourism la-bor migrants in the Jiuhua Mountain of Anhui Province, China. The research was conducted based on the in-depth in-terviewing of 15 samples, open-consultation and the analysis of secondhand data. The integration models of tourism labor migrants in the Jiuhua Mountain were formed through four processes including theoretic sampling, cod-ing-analysis, cross-tabulation and contextualization. The result shows that modes of production and life styles decide self-integration orientation of tourism labor migrants in the Jiuhua Mountain. Cultural differences are fundamental dis-similarity between tourism labor migrants and natives. There are three kinds of integration models including rapid, free and gradually advancing integration. The differences among different types of migrants’ integration models are re-markable. Taking the working integration as the abscissa and taking the life integration as the coordinate, an "S" model of integration matrix appears in the gradually advancing integration of intermediate and high administers from the working to the life which should be paid special attention to.展开更多
The high-speed railway integrated grounding system is the basic guarantee for the safe and stable operation of the railway. It is the world’s largest long-distance horizontally elongated joint grounding system, which...The high-speed railway integrated grounding system is the basic guarantee for the safe and stable operation of the railway. It is the world’s largest long-distance horizontally elongated joint grounding system, which stretches the length of hundreds to thousands of kilometers, and its structure is not only different from power station and substation grounding system, but also different from the transmission line tower, lightning rod and other small grounding devices. There is little research information on the grounding impedance of high-speed railway integrated grounding system. This paper adopted 0.618 compensation method and reverse away method respectively, measured a section of high-speed railway integrated grounding system grounding impedance by JD16 and CA6425. Measurement results are in good agreement using those two type instrument. By using 0.618 compensation method, the measurement result will be gradually converged at 0.3 Ω with the increasing of current electrode distance, which is the real grounding impedance of integrated grounding system. By using reverse away method, the maximum measurement result difference is less than 0.024 Ω with the lead of current electrode distance increasing. The measurement results will be rapidly converged 0.25 Ω. The results showed that the reverse away method is helpful to shorten the length of current electrode wiring. The measurement error will be small when the current electrode wiring is longer.展开更多
Electrical ground looks simple on a schematic; unfortunately, the actual performance of a circuit is dictated by its layout （and by its printed-circuit-board）. When the ground node moves, system performance suffers ...Electrical ground looks simple on a schematic; unfortunately, the actual performance of a circuit is dictated by its layout （and by its printed-circuit-board）. When the ground node moves, system performance suffers and the system radiates electromagnetic interferences. But the understanding of the physics of ground noise can provide an intuitive sense for reducing the problem. Ground bounce can produce transients with amplitudes of volts; most often changing magnetic flux is the cause; in this work, the authors use a Finite-Difference Time-Domain to begin to understand such phenomena. Additionally, predicting substrate cross-talks in mixed-signal circuits has become a critical issue to preserve signal integrity in future integrated systems. Phenomena that involve parasitic signal propagation into the substrate are discussed. A simple methodology to predict the substrate cross-talk and some associated tools are presented. Finally, the authors indicate a stochastic method which could grasp both outer or inner RF （Radio-Frequency） radiations and substrate parasites.展开更多
A self-organized integrated air-ground detection swarmis tentatively applied to achieve reentry vehicle landing detection,such as searching and rescuing a manned spaceship. The detectionswarm consists of multiple unma...A self-organized integrated air-ground detection swarmis tentatively applied to achieve reentry vehicle landing detection,such as searching and rescuing a manned spaceship. The detectionswarm consists of multiple unmanned aerial vehicles （UAVs）and unmanned ground vehicles （UGVs）. The UAVs can accessa detected object quickly for high mobility, while the UGVs cancomprehensively investigate the object due to the variety of carriedequipment. In addition, the integrated air-ground detectionswarm is capable of detecting from the ground and the air simultaneously.To accomplish the coordination of the UGVs andUAVs, they are all regarded as individuals of the artificial swarm.Those individuals make control decisions independently of othersbased on the self-organizing strategy. The overall requirements forthe detection swarm are analyzed, and the theoretical model ofthe self-organizing strategy based on a combined individual andenvironmental virtual function is established. The numerical investigationproves that the self-organizing strategy is suitable andscalable to control the detection swarm. To further inspect the engineeringreliability, an experiment set is established in laboratory,and the experimental demonstration shows that the self-organizingstrategy drives the detection swarm forming a close range and multiangularsurveillance configuration of a landing spot.展开更多
基金Major Program of National Natural Science Founda-tion of China (60710002)Program for Changjiang Scholars and Innovative Research Team in University
文摘This paper presents a scheme of integrated guidance and autopilot design for homing missiles against ground fixed targets. An integrated guidance and control model in the pitch plane is formulated and further changed into a normal form by nonlinear coordinate transformation. By adopting the sliding mode control approach, an adaptive nonlinear control law of the system is designed so that the missile can hit the target accurately with a desired impact attitude angle. The stability analysis of the closed-loop system is also conducted. The numerical simulation has confirmed the usefulness of the proposed design scheme.
基金Under the auspices of the Social Science Foundation of China (No. 40771059)Project of Key Research Institute of Humanities and Social Science of Anhui Provincial Education Department (No. 2008sk082rd)
文摘The grounded theory of qualitative methods was applied to researching the social integration of tourism la-bor migrants in the Jiuhua Mountain of Anhui Province, China. The research was conducted based on the in-depth in-terviewing of 15 samples, open-consultation and the analysis of secondhand data. The integration models of tourism labor migrants in the Jiuhua Mountain were formed through four processes including theoretic sampling, cod-ing-analysis, cross-tabulation and contextualization. The result shows that modes of production and life styles decide self-integration orientation of tourism labor migrants in the Jiuhua Mountain. Cultural differences are fundamental dis-similarity between tourism labor migrants and natives. There are three kinds of integration models including rapid, free and gradually advancing integration. The differences among different types of migrants’ integration models are re-markable. Taking the working integration as the abscissa and taking the life integration as the coordinate, an "S" model of integration matrix appears in the gradually advancing integration of intermediate and high administers from the working to the life which should be paid special attention to.
文摘The high-speed railway integrated grounding system is the basic guarantee for the safe and stable operation of the railway. It is the world’s largest long-distance horizontally elongated joint grounding system, which stretches the length of hundreds to thousands of kilometers, and its structure is not only different from power station and substation grounding system, but also different from the transmission line tower, lightning rod and other small grounding devices. There is little research information on the grounding impedance of high-speed railway integrated grounding system. This paper adopted 0.618 compensation method and reverse away method respectively, measured a section of high-speed railway integrated grounding system grounding impedance by JD16 and CA6425. Measurement results are in good agreement using those two type instrument. By using 0.618 compensation method, the measurement result will be gradually converged at 0.3 Ω with the increasing of current electrode distance, which is the real grounding impedance of integrated grounding system. By using reverse away method, the maximum measurement result difference is less than 0.024 Ω with the lead of current electrode distance increasing. The measurement results will be rapidly converged 0.25 Ω. The results showed that the reverse away method is helpful to shorten the length of current electrode wiring. The measurement error will be small when the current electrode wiring is longer.
文摘Electrical ground looks simple on a schematic; unfortunately, the actual performance of a circuit is dictated by its layout （and by its printed-circuit-board）. When the ground node moves, system performance suffers and the system radiates electromagnetic interferences. But the understanding of the physics of ground noise can provide an intuitive sense for reducing the problem. Ground bounce can produce transients with amplitudes of volts; most often changing magnetic flux is the cause; in this work, the authors use a Finite-Difference Time-Domain to begin to understand such phenomena. Additionally, predicting substrate cross-talks in mixed-signal circuits has become a critical issue to preserve signal integrity in future integrated systems. Phenomena that involve parasitic signal propagation into the substrate are discussed. A simple methodology to predict the substrate cross-talk and some associated tools are presented. Finally, the authors indicate a stochastic method which could grasp both outer or inner RF （Radio-Frequency） radiations and substrate parasites.
基金supported by the National Natural Science Foundation of China(11002076)the National High Technology Research and Development Program of China(863 Program)(2014AA7041002)
文摘A self-organized integrated air-ground detection swarmis tentatively applied to achieve reentry vehicle landing detection,such as searching and rescuing a manned spaceship. The detectionswarm consists of multiple unmanned aerial vehicles （UAVs）and unmanned ground vehicles （UGVs）. The UAVs can accessa detected object quickly for high mobility, while the UGVs cancomprehensively investigate the object due to the variety of carriedequipment. In addition, the integrated air-ground detectionswarm is capable of detecting from the ground and the air simultaneously.To accomplish the coordination of the UGVs andUAVs, they are all regarded as individuals of the artificial swarm.Those individuals make control decisions independently of othersbased on the self-organizing strategy. The overall requirements forthe detection swarm are analyzed, and the theoretical model ofthe self-organizing strategy based on a combined individual andenvironmental virtual function is established. The numerical investigationproves that the self-organizing strategy is suitable andscalable to control the detection swarm. To further inspect the engineeringreliability, an experiment set is established in laboratory,and the experimental demonstration shows that the self-organizingstrategy drives the detection swarm forming a close range and multiangularsurveillance configuration of a landing spot.
