An unmanned aerial vehicle （UAV） is arranged to explore an unknown environment and to map the features it finds when GPS is denied.It navigates using a statistical estimation technique known as simultaneous localiza...An unmanned aerial vehicle （UAV） is arranged to explore an unknown environment and to map the features it finds when GPS is denied.It navigates using a statistical estimation technique known as simultaneous localization and mapping （SLAM） which allows for the simultaneous estimation of the location of the UAV as well as the location of the features it sees.Obscrvability is a key aspect of the state estimation problem of SLAM.However,the dimension and variables of SLAM system might be changed with new features.To solve this issue,a unified approach of observability analysis for SLAM system is provided,through reorganizing the system model.The dimension and variables of SLAM system keep steady,then the PWCS theory can be used to analyze the local or total observability,and under special maneuver,some system states,such as the yaw angle,become observable.Simulation results validate the proposed method.展开更多
Unmanned aerial vehicle(UAV)was introduced to take road segment traffic surveillance.Considering the limited UAV maximum flight distance,UAV route planning problem was studied.First,a multi-objective optimization mode...Unmanned aerial vehicle(UAV)was introduced to take road segment traffic surveillance.Considering the limited UAV maximum flight distance,UAV route planning problem was studied.First,a multi-objective optimization model of planning UAV route for road segment surveillance was proposed,which aimed to minimize UAV cruise distance and minimize the number of UAVs used.Then,an evolutionary algorithm based on Pareto optimality technique was proposed to solve multi-objective UAV route planning problem.At last,a UAV flight experiment was conducted to test UAV route planning effect,and a case with three scenarios was studied to analyze the impact of different road segment lengths on UAV route planning.The case results show that the optimized cruise distance and the number of UAVs used decrease by an average of 38.43% and 33.33%,respectively.Additionally,shortening or extending the length of road segments has different impacts on UAV route planning.展开更多
This paper presents a low-cost remote vision system for use in unmanned aircraft that provide a first person view （FPV） to vehicle operators in real-time. The system does not require a traditional electromechanical ...This paper presents a low-cost remote vision system for use in unmanned aircraft that provide a first person view （FPV） to vehicle operators in real-time. The system does not require a traditional electromechanical gimbal setup. Instead, the system uses a wide-angle （fisheye） lens and a video camera setup that is fixed on the vehicle and captures the full viewing area as seen from the cockpit in each video frame. Video is transmitted to a ground station wirelessly. On the ground, the pilot is outfitted with virtual reality goggles with integrated attitude and heading sensors. The received video is recertified and cropped by the ground station to provide the goggles with the appropriate view based on head orientation. Compared to traditional electromechanical setups, the presented system features reduced weight, reduced video lag, lower power consumption, and reduced drag on the airborne vehicle in addition to requiring only a unidirectional downlink. The video processing is preformed on the ground, further reducing computational resources and bandwidth requirements. These advantages, in conjunction with the advancement in miniature optical sensors and lenses, make the proposed approach a viable option for miniature remotely controlled vehicles. The system was successfully implemented and tested using an R/C airplane.展开更多
Anatolia, also named as Asia Minor, is known as one of the gene centers for a number of the life forms in the world. Caucasian honeybee is one of the important gene resources in Anatolia and mountain type is the most ...Anatolia, also named as Asia Minor, is known as one of the gene centers for a number of the life forms in the world. Caucasian honeybee is one of the important gene resources in Anatolia and mountain type is the most significant variant. This honeybee race is black colored and similar to the Carniola bees regarding shape, size and hair cover. Body is moderate structured, slim and long as abdomen is thin. Chitin is dark. Hair cover is black and short （0.335 ± 0.031 ram）. Hair color of worker bees is livid grey as chest hair color of drones is black. All abdominal rings are black colored. It has the longest tongue （7.046 ±0.189 mm） among the all honeybee races. Caucasian bees form strong colonies but their colonial development is slow. They swarm only very little and are good tempered. They are good pollinators for alfalfa, clover and similar plants with deep tube flowers and can work under unfavourable conditions. It is known that homeland of Caucasian bee （A. mellifera caucasica） is upper valleys of mid-Caueasia （Georgia, Azerbaijan and Northern Caucasus）. Its distribution area is extended to Kars, Ardahan and Artvin provinces in North-Eastern Anatolia of Turkey. The area including Posof district of Ardahan province and its all villages and 6 villages of Camili basin in Borka district of Artvin province is housing different eeotypes of this race. So, this area was isolated for gene conservation of Caucasian bee by Ministry of Agriculture and Rural Affairs in 2008. In-situ conservation studies for Caucasian bee （A. mellifera caucasica Gorbachev） have been continuing under the Indigenous Gene Resources Conservation Scheme with a total of 6,960 colonies under on-farm conditions.展开更多
Advanced flow measurement and active flow control need the development of new type devices and systems.Micro-electro-mechanical systems(MEMS) technologies become the important and feasible approach for micro transduce...Advanced flow measurement and active flow control need the development of new type devices and systems.Micro-electro-mechanical systems(MEMS) technologies become the important and feasible approach for micro transducers fabrication.This paper introduces research works of MEMS/NEMS Lab in flow measurement sensors and active flow control actuators.Micro sensors include the flexible thermal sensor array,capacitive shear stress sensor and high sensitivity pressure sensor.Micro actuators are the balloon actuator and synthetic jet actuator respectively.Through wind tunnel test,these micro transducers achieve the goals of shear stress and pressure distribution measurement,boundary layer separation control,lift enhancement,etc.And unmanned aerial vehicle(UAV) flight test verifies the ability of maneuver control of micro actuator.In the future work,micro sensor and actuator can be combined into a closed-loop control system to construct aerodynamic smart skin system for aircraft.展开更多
基金Project(2020203)supported by the Weapon Research Foundation,China
文摘An unmanned aerial vehicle （UAV） is arranged to explore an unknown environment and to map the features it finds when GPS is denied.It navigates using a statistical estimation technique known as simultaneous localization and mapping （SLAM） which allows for the simultaneous estimation of the location of the UAV as well as the location of the features it sees.Obscrvability is a key aspect of the state estimation problem of SLAM.However,the dimension and variables of SLAM system might be changed with new features.To solve this issue,a unified approach of observability analysis for SLAM system is provided,through reorganizing the system model.The dimension and variables of SLAM system keep steady,then the PWCS theory can be used to analyze the local or total observability,and under special maneuver,some system states,such as the yaw angle,become observable.Simulation results validate the proposed method.
基金Project(2009AA11Z220)supported by National High Technology Research and Development Program of ChinaProjects(61070112,61070116)supported by the National Natural Science Foundation of China+1 种基金Project(2012LLYJTJSJ077)supported by the Ministry of Public Security of ChinaProject(KYQD14003)supported by Tianjin University of Technology and Education,China
文摘Unmanned aerial vehicle(UAV)was introduced to take road segment traffic surveillance.Considering the limited UAV maximum flight distance,UAV route planning problem was studied.First,a multi-objective optimization model of planning UAV route for road segment surveillance was proposed,which aimed to minimize UAV cruise distance and minimize the number of UAVs used.Then,an evolutionary algorithm based on Pareto optimality technique was proposed to solve multi-objective UAV route planning problem.At last,a UAV flight experiment was conducted to test UAV route planning effect,and a case with three scenarios was studied to analyze the impact of different road segment lengths on UAV route planning.The case results show that the optimized cruise distance and the number of UAVs used decrease by an average of 38.43% and 33.33%,respectively.Additionally,shortening or extending the length of road segments has different impacts on UAV route planning.
文摘This paper presents a low-cost remote vision system for use in unmanned aircraft that provide a first person view （FPV） to vehicle operators in real-time. The system does not require a traditional electromechanical gimbal setup. Instead, the system uses a wide-angle （fisheye） lens and a video camera setup that is fixed on the vehicle and captures the full viewing area as seen from the cockpit in each video frame. Video is transmitted to a ground station wirelessly. On the ground, the pilot is outfitted with virtual reality goggles with integrated attitude and heading sensors. The received video is recertified and cropped by the ground station to provide the goggles with the appropriate view based on head orientation. Compared to traditional electromechanical setups, the presented system features reduced weight, reduced video lag, lower power consumption, and reduced drag on the airborne vehicle in addition to requiring only a unidirectional downlink. The video processing is preformed on the ground, further reducing computational resources and bandwidth requirements. These advantages, in conjunction with the advancement in miniature optical sensors and lenses, make the proposed approach a viable option for miniature remotely controlled vehicles. The system was successfully implemented and tested using an R/C airplane.
文摘Anatolia, also named as Asia Minor, is known as one of the gene centers for a number of the life forms in the world. Caucasian honeybee is one of the important gene resources in Anatolia and mountain type is the most significant variant. This honeybee race is black colored and similar to the Carniola bees regarding shape, size and hair cover. Body is moderate structured, slim and long as abdomen is thin. Chitin is dark. Hair cover is black and short （0.335 ± 0.031 ram）. Hair color of worker bees is livid grey as chest hair color of drones is black. All abdominal rings are black colored. It has the longest tongue （7.046 ±0.189 mm） among the all honeybee races. Caucasian bees form strong colonies but their colonial development is slow. They swarm only very little and are good tempered. They are good pollinators for alfalfa, clover and similar plants with deep tube flowers and can work under unfavourable conditions. It is known that homeland of Caucasian bee （A. mellifera caucasica） is upper valleys of mid-Caueasia （Georgia, Azerbaijan and Northern Caucasus）. Its distribution area is extended to Kars, Ardahan and Artvin provinces in North-Eastern Anatolia of Turkey. The area including Posof district of Ardahan province and its all villages and 6 villages of Camili basin in Borka district of Artvin province is housing different eeotypes of this race. So, this area was isolated for gene conservation of Caucasian bee by Ministry of Agriculture and Rural Affairs in 2008. In-situ conservation studies for Caucasian bee （A. mellifera caucasica Gorbachev） have been continuing under the Indigenous Gene Resources Conservation Scheme with a total of 6,960 colonies under on-farm conditions.
基金National Natural Science Foundation of China (No. 90305017No. 50775188No. 51105317)
文摘Advanced flow measurement and active flow control need the development of new type devices and systems.Micro-electro-mechanical systems(MEMS) technologies become the important and feasible approach for micro transducers fabrication.This paper introduces research works of MEMS/NEMS Lab in flow measurement sensors and active flow control actuators.Micro sensors include the flexible thermal sensor array,capacitive shear stress sensor and high sensitivity pressure sensor.Micro actuators are the balloon actuator and synthetic jet actuator respectively.Through wind tunnel test,these micro transducers achieve the goals of shear stress and pressure distribution measurement,boundary layer separation control,lift enhancement,etc.And unmanned aerial vehicle(UAV) flight test verifies the ability of maneuver control of micro actuator.In the future work,micro sensor and actuator can be combined into a closed-loop control system to construct aerodynamic smart skin system for aircraft.
