• Journal of information and communication convergence engineering
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• v.17 no.1
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• pp.84-90
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• 2019

Applications of unmanned aerial vehicles (UAVs) in the military environment have become popular because they require minimum human contribution and can avoid accidents during missions. UAVs are employed in various missions such as reconnaissance, observation, aggression, and protection. Consequently, counter-measures, known as anti-drone technologies, have been developed as well. In order to protect against threats from anti-drone technologies and enhance the survivability of UAVs, this study proposes an evasive measure. The proposed bio-inspired evasive maneuver of a UAV mimics a dragonfly's irregular flight. The unpredictable UAV movement is able to confuse enemies and avoid threats, thereby enhancing the UAV's survivability. The proposed system has been implemented on a commercial UAV platform (AR Drone 2.0) and tested in a real environment. The experiment results demonstrate that the proposed flight pattern has larger displacement values compared to a regular flight maneuver, thus making the UAV's position is difficult to predict.

• Applied Microscopy
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• v.32 no.3
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• pp.291-301
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• 2002

The present study was performed to compare the morphological differences of flight muscles among 3 species from insects (Xylocopa appendiculata circumvolans Smith, Davidins lunatus B. and Serrognathus platymelus castanicdor M.) by investigating ultrastructural observation and stereological analysis. Xylocopa appendiculata circumvolans Smith has the most flight hours. In addition, the number and arrangement of mitochondria and the structure of sarcomere were similar to those of vertebrates. However sarcomere structure of Davidins lunatus B. was irregular and the sarcomere length was longer than that of Xylocopa appendiculata circumvolans Smith. In Serrognathus platymelus castanicdor M. which has the least flight hours, the length of sarcomere appeared longer than that of Davidins lunatus B. In results of stereological analysis, Serrognathus platymelus castanicdor M. had the highest volume density of myofibrils in all species. The volume and numerical density of mitochondria and the volume density of sarcoplasmic reticulum were highest Xylocopa appendiculata circumvolans Smith and Davidins lunatus B. respectively. This study suggests that the flight hours and flight pattern by different ecological habitats may cause the morphological changes of flight muscle.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.659-665
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• 2010

This paper proposes a control algorithm for quadruped robots moving on irregularly sloped uneven surfaces. Since the body balance of a quadruped robot is controlled by the forces acting on its feet during touchdown, the ground reaction force (GRF) is controlled for stable running. The desired GRF for each foot is generated on the basis of the desired galloping pattern; this GRF is then compared with the actual contact force. The difference between the two forces is used to modify the foot trajectory. The desired force is realized by considering a combination of the rate change of the angular and linear momenta at flight. Then, the amplitude of the GRF to be applied at each foot in order to achieve the desired linear and angular momenta is determined by fuzzy logic. Dynamic simulations of galloping motion were performed using RecurDyn; these simulations show that the proposed control method can be used to achieve stable galloping for a quadruped robot on irregularly sloped uneven surfaces.