In order to fulfill the goal of autonomous walking on rough terrain,a distributed gait planningmethod applied to hexapod biomimetic robot locomotion is proposed based on the research effort of gait co-ordination mecha...In order to fulfill the goal of autonomous walking on rough terrain,a distributed gait planningmethod applied to hexapod biomimetic robot locomotion is proposed based on the research effort of gait co-ordination mechanism of stick insect.The mathematical relation of walking velocity and gait pattern wasdepicted,a set of local rules operating between adjacent legs were put forward,and a distributed networkof local rules for gait control was constructed.With the interaction of adjacent legs,adaptive adjustmentof phase sequence fluctuation of walking legs resulting from change of terrain conditions or variety of walk-ing speed was implemented to generate statically stable gait.In the simulation experiments,adaptive ad-justment of inter-leg phase sequence and smooth transition of velocity and gait pattern were realized,andstatic stableness was ensured simultaneously,which provided the hexapod robot with the capability ofwalking on rough terrain stably and expeditiously.展开更多
Flexible net barriers are a new type of effective mitigation measure against debris flows in valleys and can affect the kinematic energy and mass of debris flows. Here, ten flume tests were performed to study the dyna...Flexible net barriers are a new type of effective mitigation measure against debris flows in valleys and can affect the kinematic energy and mass of debris flows. Here, ten flume tests were performed to study the dynamic behaviours of debris flows with differences in volumes, concentrations(solid volume fraction), and travel distances after interception by a uniform flexible net barrier. A high-speed camera was used to monitor the whole test process, and their dynamic behaviours were recorded. A preliminary computational framework on energy conversion is proposed according to the deposition mechanisms and outflow of debris flow under the effects of the flexible net barrier. The experimental results show that the dynamic interaction process between a debris flow and the flexible net barrier can be divided into two stages:(a) the two-phase impact of the leading edge of the debris flow with the net and(b) collision and friction between the body of the debris flow and intercepted debris material. The approach velocity of a debris flow decreases sharply(a maximum of 63%) after the interception by the net barrier, and the mass ratio of the debris material being intercepted and the kinetic energy ratio of the debris material being absorbed by the net barrier are close due to the limited interception efficiency of the flexible net barrier, which is believed to be related to the flexibility. The energy ratio of outflow is relative small despite the large permeability of the flexible net barrier.展开更多
To simulate the dynamic responses of the multibody system with a floating base when the upper parts spread with a certain sequence and relative speed, the homogeneous matrix method is employed to model and simulate a ...To simulate the dynamic responses of the multibody system with a floating base when the upper parts spread with a certain sequence and relative speed, the homogeneous matrix method is employed to model and simulate a four-body system with a floating base and the motions are analyzed when the upper parts are spread sequentially or synchronously. The rolling, swaying and heaving temporal variations are obtained when the multibody system is under the conditions of the static water along with the wave loads and the mean wind loads or the single pulse wind loads, respectively. The moment variations of each joint under the single pulse wind load are also gained. The numerical results showed that the swaying of the floating base is almost not influenced by the spreading time or form when the upper parts spread sequentially or synchronously, while the rolling and the heaving mainly depend on the spreading time and forms. The swaying and heaving motions are influenced significantly by the mean wind loads. The single pulse wind load also has influences on the dynamic responses. The torque of joint 3 and joint 4 in the single pulse wind environment may be twice that in the windless environment when the system spreads with 60 s duration.展开更多
My paper aims to discuss the approach between the mystic＇s experience and the experiment of the scientist. The mystic experience is closer to what is proper to the scientific experiment： both are, finally, ways of t...My paper aims to discuss the approach between the mystic＇s experience and the experiment of the scientist. The mystic experience is closer to what is proper to the scientific experiment： both are, finally, ways of tryout. This also means that both are ways to come closer to a deeper understanding of Reality. Raising the problem of the relation between religion and science requires a series of precautions, especially related to the underlying meanings of what we call ＂religion＂ or ＂science＂. What is meant by religion and religious？ The terms are too vague, and on the other hand, the differences among religions are so important that it is almost impossible to use the term religion without an abstract meaning. Even the overall invocation of Christianity is improper, as the report of Eastern Christianity to the Western, one reveals different perspectives on some issues that determine the relationship with science. There must be also taken into account the history of the religious doctrines after Enlightenment, as they underwent secular influences that sometimes left tracks in their discourse, the most aggressive factor being the ideological one. And when speaking about the possibility of religion getting open to science it is necessary to specify what type of religious discourse is concerned. Since a generic report of religion to science is slippery, we should rather count on the identification of those types of religious experience and of those religious horizons that can offer a real openness to science. These statements are also true for science： for such a dialogue, there is need of identifying those aspects of science that are not contaminated by ideology or by assumptions alien to its experimental nature.展开更多
基金Supported by the National High Technology Research and Development Programme of China (No. 2006AA04Z245)by the Progran for Changjiang Scholars and Innovative Research Team in University of China (PCSIRT) (IRT0423)
文摘In order to fulfill the goal of autonomous walking on rough terrain,a distributed gait planningmethod applied to hexapod biomimetic robot locomotion is proposed based on the research effort of gait co-ordination mechanism of stick insect.The mathematical relation of walking velocity and gait pattern wasdepicted,a set of local rules operating between adjacent legs were put forward,and a distributed networkof local rules for gait control was constructed.With the interaction of adjacent legs,adaptive adjustmentof phase sequence fluctuation of walking legs resulting from change of terrain conditions or variety of walk-ing speed was implemented to generate statically stable gait.In the simulation experiments,adaptive ad-justment of inter-leg phase sequence and smooth transition of velocity and gait pattern were realized,andstatic stableness was ensured simultaneously,which provided the hexapod robot with the capability ofwalking on rough terrain stably and expeditiously.
基金supported by the National Natural Science Foundation of China (51639007)the Youth Science and Technology Fund of Sichuan Province (2016JQ0011)the Science and Technology Fund of Chengdu Water Authority (14H1055).
文摘Flexible net barriers are a new type of effective mitigation measure against debris flows in valleys and can affect the kinematic energy and mass of debris flows. Here, ten flume tests were performed to study the dynamic behaviours of debris flows with differences in volumes, concentrations(solid volume fraction), and travel distances after interception by a uniform flexible net barrier. A high-speed camera was used to monitor the whole test process, and their dynamic behaviours were recorded. A preliminary computational framework on energy conversion is proposed according to the deposition mechanisms and outflow of debris flow under the effects of the flexible net barrier. The experimental results show that the dynamic interaction process between a debris flow and the flexible net barrier can be divided into two stages:(a) the two-phase impact of the leading edge of the debris flow with the net and(b) collision and friction between the body of the debris flow and intercepted debris material. The approach velocity of a debris flow decreases sharply(a maximum of 63%) after the interception by the net barrier, and the mass ratio of the debris material being intercepted and the kinetic energy ratio of the debris material being absorbed by the net barrier are close due to the limited interception efficiency of the flexible net barrier, which is believed to be related to the flexibility. The energy ratio of outflow is relative small despite the large permeability of the flexible net barrier.
基金the National Natural Science Foundation of China，Major State Basic Research Development Program of China （973 Program）
文摘To simulate the dynamic responses of the multibody system with a floating base when the upper parts spread with a certain sequence and relative speed, the homogeneous matrix method is employed to model and simulate a four-body system with a floating base and the motions are analyzed when the upper parts are spread sequentially or synchronously. The rolling, swaying and heaving temporal variations are obtained when the multibody system is under the conditions of the static water along with the wave loads and the mean wind loads or the single pulse wind loads, respectively. The moment variations of each joint under the single pulse wind load are also gained. The numerical results showed that the swaying of the floating base is almost not influenced by the spreading time or form when the upper parts spread sequentially or synchronously, while the rolling and the heaving mainly depend on the spreading time and forms. The swaying and heaving motions are influenced significantly by the mean wind loads. The single pulse wind load also has influences on the dynamic responses. The torque of joint 3 and joint 4 in the single pulse wind environment may be twice that in the windless environment when the system spreads with 60 s duration.
文摘My paper aims to discuss the approach between the mystic＇s experience and the experiment of the scientist. The mystic experience is closer to what is proper to the scientific experiment： both are, finally, ways of tryout. This also means that both are ways to come closer to a deeper understanding of Reality. Raising the problem of the relation between religion and science requires a series of precautions, especially related to the underlying meanings of what we call ＂religion＂ or ＂science＂. What is meant by religion and religious？ The terms are too vague, and on the other hand, the differences among religions are so important that it is almost impossible to use the term religion without an abstract meaning. Even the overall invocation of Christianity is improper, as the report of Eastern Christianity to the Western, one reveals different perspectives on some issues that determine the relationship with science. There must be also taken into account the history of the religious doctrines after Enlightenment, as they underwent secular influences that sometimes left tracks in their discourse, the most aggressive factor being the ideological one. And when speaking about the possibility of religion getting open to science it is necessary to specify what type of religious discourse is concerned. Since a generic report of religion to science is slippery, we should rather count on the identification of those types of religious experience and of those religious horizons that can offer a real openness to science. These statements are also true for science： for such a dialogue, there is need of identifying those aspects of science that are not contaminated by ideology or by assumptions alien to its experimental nature.
