摘要 :
The requirements for this project as described above contain basic guidelines for this Senior Design project. First and foremost, we must come up with a way to replace tradition servo controlled surfaces with MFC actuated surfaces...
展开
The requirements for this project as described above contain basic guidelines for this Senior Design project. First and foremost, we must come up with a way to replace tradition servo controlled surfaces with MFC actuated surfaces in an effective manner. Not only will the control surfaces need to respond as well as, if not better than, the classic servo-motor system, but it will also need to be a fairly simple, potentially cost effective design that can easily be reproduced. The overall goal of this project is to showcase the capabilities of MFCs on an aircraft that could be reproduced on a large scale in today's R/C market.
收起
摘要 :
The requirements for this project as described above contain basic guidelines for this Senior Design project. First and foremost, we must come up with a way to replace tradition servo controlled surfaces with MFC actuated surfaces...
展开
The requirements for this project as described above contain basic guidelines for this Senior Design project. First and foremost, we must come up with a way to replace tradition servo controlled surfaces with MFC actuated surfaces in an effective manner. Not only will the control surfaces need to respond as well as, if not better than, the classic servo-motor system, but it will also need to be a fairly simple, potentially cost effective design that can easily be reproduced. The overall goal of this project is to showcase the capabilities of MFCs on an aircraft that could be reproduced on a large scale in today's R/C market.
收起
摘要 :
Current small radio-controlled aircraft typically use servomechanisms linked to independent control surfaces to provide flight control. A servomechanism consists of a large number of moving parts such as gears, bearings, shafts, m...
展开
Current small radio-controlled aircraft typically use servomechanisms linked to independent control surfaces to provide flight control. A servomechanism consists of a large number of moving parts such as gears, bearings, shafts, motor coils, etc. The complexity of a servo requires a considerable percentage of the volume, power and weight of the entire aircraft. The overall aircraft performance is strongly dependant on these characteristics - volume, power, weight - therefore it is desirable to minimize the power consumption, volume occupied and weight of the control system. Another disadvantage of a servo actuated control system is the drag penalty that results from control linkages, horns, hinges and the discontinuities between the control surface and the stabilizer or wing. A more efficient control system for radio-controlled aircraft is desired.
收起
摘要 :
Current small radio-controlled aircraft typically use servomechanisms linked to independent control surfaces to provide flight control. A servomechanism consists of a large number of moving parts such as gears, bearings, shafts, m...
展开
Current small radio-controlled aircraft typically use servomechanisms linked to independent control surfaces to provide flight control. A servomechanism consists of a large number of moving parts such as gears, bearings, shafts, motor coils, etc. The complexity of a servo requires a considerable percentage of the volume, power and weight of the entire aircraft. The overall aircraft performance is strongly dependant on these characteristics - volume, power, weight - therefore it is desirable to minimize the power consumption, volume occupied and weight of the control system. Another disadvantage of a servo actuated control system is the drag penalty that results from control linkages, horns, hinges and the discontinuities between the control surface and the stabilizer or wing. A more efficient control system for radio-controlled aircraft is desired.
收起
摘要 :
This paper presents the final results of the 2010 Virginia Tech Wing Morphing Design Team (a senior design project between the departments of Mechanical Engineering and Aerospace and Ocean Engineering) which has developed a comple...
展开
This paper presents the final results of the 2010 Virginia Tech Wing Morphing Design Team (a senior design project between the departments of Mechanical Engineering and Aerospace and Ocean Engineering) which has developed a completely servo-less, piezoelectric controlled, wind tunnel and flight tested, remotely piloted aircraft. A type of piezoceramic composite actuator known as Macro-Fiber Composite (MFC) is used for changing the camber of all control surfaces on the aircraft. The aircraft is analyzed theoretically for its two- and three- dimensional aerodynamic characteristics to aid the design of the piezoelectric control surfaces. A vortex-lattice analysis complemented the database of aerodynamic derivatives used to analyze control response. Steady state roll rates are measured in a wind tunnel and compared to a similar aircraft with servomotor actuated control surfaces. The theoretical analysis and wind tunnel testing demonstrated the stability and control authority of the concept, culminating in a landmark first flight of the completely MFC controlled aircraft on April 29, 2010. An electric motor driven propulsion system is used to generate thrust and all systems (including the high voltage converters) are powered with a single Lithium-Polymer battery. This vehicle became the first completely MFC controlled, flight tested aircraft. It is also known to be the first fully solid-state piezoelectric material controlled, non-tethered, flight tested fixed-wing aircraft.
收起
摘要 :
This paper presents the final results of the 2010 Virginia Tech Wing Morphing Design Team (a senior design project between the departments of Mechanical Engineering and Aerospace and Ocean Engineering) which has developed a comple...
展开
This paper presents the final results of the 2010 Virginia Tech Wing Morphing Design Team (a senior design project between the departments of Mechanical Engineering and Aerospace and Ocean Engineering) which has developed a completely servo-less, piezoelectric controlled, wind tunnel and flight tested, remotely piloted aircraft. A type of piezoceramic composite actuator known as Macro-Fiber Composite (MFC) is used for changing the camber of all control surfaces on the aircraft. The aircraft is analyzed theoretically for its two- and three- dimensional aerodynamic characteristics to aid the design of the piezoelectric control surfaces. A vortex-lattice analysis complemented the database of aerodynamic derivatives used to analyze control response. Steady state roll rates are measured in a wind tunnel and compared to a similar aircraft with servomotor actuated control surfaces. The theoretical analysis and wind tunnel testing demonstrated the stability and control authority of the concept, culminating in a landmark first flight of the completely MFC controlled aircraft on April 29, 2010. An electric motor driven propulsion system is used to generate thrust and all systems (including the high voltage converters) are powered with a single Lithium-Polymer battery. This vehicle became the first completely MFC controlled, flight tested aircraft. It is also known to be the first fully solid-state piezoelectric material controlled, non-tethered, flight tested fixed-wing aircraft.
收起
摘要 :
This paper investigates the problem of planning a minimum-length tour for a three-dimensional Dubins airplane model to visually inspect a series of targets located on the ground or exterior surface of objects in an urban environme...
展开
This paper investigates the problem of planning a minimum-length tour for a three-dimensional Dubins airplane model to visually inspect a series of targets located on the ground or exterior surface of objects in an urban environment. Objects are 2.5D extruded polygons representing buildings or other structures. A visibility volume defines the set of admissible (occlusion-free) viewing locations for each target that satisfy feasible airspace and imaging constraints. The Dubins traveling salesperson problem with neighborhoods (DTSPN) is extended to three dimensions with visibility volumes that are approximated by triangular meshes. Four sampling algorithms are proposed for sampling vehicle configurations within each visibility volume to define vertices of the underlying DTSPN. Additionally, a heuristic approach is proposed to improve computation time by approximating edge costs of the 3D Dubins airplane with a lower bound that is used to solve for a sequence of viewing locations. The viewing locations are then assigned pitch and heading angles based on their relative geometry. The proposed sampling methods and heuristics are compared through a Monte-Carlo experiment that simulates view planning tours over a realistic urban environment.
收起
摘要 :
This paper investigates the problem of planning a minimum-length tour for a three-dimensional Dubins airplane model to visually inspect a series of targets located on the ground or exterior surface of objects in an urban environme...
展开
This paper investigates the problem of planning a minimum-length tour for a three-dimensional Dubins airplane model to visually inspect a series of targets located on the ground or exterior surface of objects in an urban environment. Objects are 2.5D extruded polygons representing buildings or other structures. A visibility volume defines the set of admissible (occlusion-free) viewing locations for each target that satisfy feasible airspace and imaging constraints. The Dubins traveling salesperson problem with neighborhoods (DTSPN) is extended to three dimensions with visibility volumes that are approximated by triangular meshes. Four sampling algorithms are proposed for sampling vehicle configurations within each visibility volume to define vertices of the underlying DTSPN. Additionally, a heuristic approach is proposed to improve computation time by approximating edge costs of the 3D Dubins airplane with a lower bound that is used to solve for a sequence of viewing locations. The viewing locations are then assigned pitch and heading angles based on their relative geometry. The proposed sampling methods and heuristics are compared through a Monte-Carlo experiment that simulates view planning tours over a realistic urban environment.
收起
摘要 :
The Department of Aerospace and Ocean Engineering of Virginia Tech designed and built a new fleet of UAVs for use in augmenting the aircraft flight mechanics curriculum for undergraduates. This paper describes the flight testing o...
展开
The Department of Aerospace and Ocean Engineering of Virginia Tech designed and built a new fleet of UAVs for use in augmenting the aircraft flight mechanics curriculum for undergraduates. This paper describes the flight testing of this new UAV. Issues as-sociated with autonomous UAV flight testing are discussed and compared to traditional manned flight testing. Lessons learned during testing and data reduction are presented. Analysis results include specific excess power for a large portion of the UAV's flight en-velope, stability derivatives derived from experimental test, and airspeed for best range in a glide. Further the short period, dutch roll, and roll modes are excited and then characterized for the UAV.
收起
摘要 :
We evaluate the use of a probability hypothesis density (PHD) filter in a bearings-only tracking application. The
main feature of a PHD filter is that it propagates the first-order statistical moment of a multisource posterior
d...
展开
We evaluate the use of a probability hypothesis density (PHD) filter in a bearings-only tracking application. The
main feature of a PHD filter is that it propagates the first-order statistical moment of a multisource posterior
distribution. Multisource estimation using a PHD filter has been shown to reliably track multiple simulated
targets in the bearings-only case. In this paper we evaluate the utility of the sequential Monte-Carlo PHD filter
for tracking surface ships using bearings-only data acquired from a Bluefin-21 unmanned underwater vehicle in
Boston Harbor. The unmanned underwater vehicle was equipped with a rigidly mounted planar hydrophone array
that measures the bearing angle to sources of acoustic noise, of which shipping traffic is the dominant source.
We further evaluate several target maneuvering models, including clockwise and counter-clockwise coordinated
turns. The combination of the coordinated turn models with a constant velocity model is used in a multiple
model PHD filter. The results of the multiple model PHD filter are compared to the results of a PHD filter using
only a constant velocity model.
收起
原文获取