The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Francois Xavier Russotto - One of the best experts on this subject based on the ideXlab platform.
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a Terrain Following control approach for a vtol unmanned aerial vehicle using average optical flow
Autonomous Robots, 2010Co-Authors: Bruno Herisse, Tarek Hamel, Robert Mahony, Francois Xavier RussottoAbstract:This paper presents a nonlinear controller for Terrain Following of a vertical take-off and landing vehicle (VTOL). The VTOL vehicle is assumed to be a rigid body, equipped with a minimum sensor suite (camera, IMU and barometric altimeter) maneuvering over a textured rough Terrain made of a concatenation of planar surfaces. Assuming that the forward velocity is separately regulated to a desired value, the proposed control approach ensures Terrain Following and guarantees that the vehicle does not collide with the ground during the task. The proposed control acquires an optical flow from multiple spatially separate observation points, typically obtained via multiple cameras or non collinear directions in a unique camera. The proposed control algorithm has been tested extensively in simulation and then implemented on a quadrotor UAV to demonstrate the performance of the closed-loop system.
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A general optical flow based Terrain-Following strategy for a VTOL UAV using multiple views
Proceedings - IEEE International Conference on Robotics and Automation, 2010Co-Authors: Bruno Herisse, Sophie Oustrieres, Tarek Hamel, Robert Mahony, Francois Xavier RussottoAbstract:This paper presents a general approach for Terrain Following (including obstacle avoidance) of a vertical take-off and landing vehicle (VTOL) using multiple observation points. The VTOL vehicle is assumed to be a rigid body, equipped with a minimum sensor suite (camera, IMU and barometric altimeter), manoeuvering over a textured rough Terrain made of a concatenation of planar surfaces. Assuming that the forward velocity is separately regulated to a desired non-zero value, the proposed control approach ensures Terrain Following and guarantees the vehicle does not collide with obstacles during the task. The proposed control acquires an optical flow from multiple spatially separate observation points, typically obtained via multiple cameras or non collinear directions in a unique camera. The proposed control algorithm has been tested extensively in simulation and then implemented on a quadrotor UAV to demonstrate the performance of the closed loop system.
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a nonlinear Terrain Following controller for a vtol unmanned aerial vehicle using translational optical flow
International Conference on Robotics and Automation, 2009Co-Authors: Bruno Herisse, Tarek Hamel, Robert Mahony, Francois Xavier RussottoAbstract:This paper presents a nonlinear controller for Terrain Following of a vertical take-off and landing vehicle (VTOL). The VTOL vehicle is assumed to be a rigid body, equipped with a minimum sensor suite (camera and IMU) along with a measure of the forward speed from another sensor such as global positioning system, maneuvering over a textured Terrain made of planar surfaces. Assuming that the forward velocity is separately set to a desired value, the proposed control approach ensures Terrain Following and guaranties the vehicle does not collide with the ground during the task. The proposed control acquires an optical flow from three spatially separate observation points, typically obtained via three cameras or three non collinear directions in a unique camera. The proposed control algorithm has been tested extensively in simulation and then implemented on a quadrotor UAV to demonstrate the performance of the closed loop system.
Bruno Herisse - One of the best experts on this subject based on the ideXlab platform.
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a Terrain Following control approach for a vtol unmanned aerial vehicle using average optical flow
Autonomous Robots, 2010Co-Authors: Bruno Herisse, Tarek Hamel, Robert Mahony, Francois Xavier RussottoAbstract:This paper presents a nonlinear controller for Terrain Following of a vertical take-off and landing vehicle (VTOL). The VTOL vehicle is assumed to be a rigid body, equipped with a minimum sensor suite (camera, IMU and barometric altimeter) maneuvering over a textured rough Terrain made of a concatenation of planar surfaces. Assuming that the forward velocity is separately regulated to a desired value, the proposed control approach ensures Terrain Following and guarantees that the vehicle does not collide with the ground during the task. The proposed control acquires an optical flow from multiple spatially separate observation points, typically obtained via multiple cameras or non collinear directions in a unique camera. The proposed control algorithm has been tested extensively in simulation and then implemented on a quadrotor UAV to demonstrate the performance of the closed-loop system.
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A general optical flow based Terrain-Following strategy for a VTOL UAV using multiple views
Proceedings - IEEE International Conference on Robotics and Automation, 2010Co-Authors: Bruno Herisse, Sophie Oustrieres, Tarek Hamel, Robert Mahony, Francois Xavier RussottoAbstract:This paper presents a general approach for Terrain Following (including obstacle avoidance) of a vertical take-off and landing vehicle (VTOL) using multiple observation points. The VTOL vehicle is assumed to be a rigid body, equipped with a minimum sensor suite (camera, IMU and barometric altimeter), manoeuvering over a textured rough Terrain made of a concatenation of planar surfaces. Assuming that the forward velocity is separately regulated to a desired non-zero value, the proposed control approach ensures Terrain Following and guarantees the vehicle does not collide with obstacles during the task. The proposed control acquires an optical flow from multiple spatially separate observation points, typically obtained via multiple cameras or non collinear directions in a unique camera. The proposed control algorithm has been tested extensively in simulation and then implemented on a quadrotor UAV to demonstrate the performance of the closed loop system.
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a nonlinear Terrain Following controller for a vtol unmanned aerial vehicle using translational optical flow
International Conference on Robotics and Automation, 2009Co-Authors: Bruno Herisse, Tarek Hamel, Robert Mahony, Francois Xavier RussottoAbstract:This paper presents a nonlinear controller for Terrain Following of a vertical take-off and landing vehicle (VTOL). The VTOL vehicle is assumed to be a rigid body, equipped with a minimum sensor suite (camera and IMU) along with a measure of the forward speed from another sensor such as global positioning system, maneuvering over a textured Terrain made of planar surfaces. Assuming that the forward velocity is separately set to a desired value, the proposed control approach ensures Terrain Following and guaranties the vehicle does not collide with the ground during the task. The proposed control acquires an optical flow from three spatially separate observation points, typically obtained via three cameras or three non collinear directions in a unique camera. The proposed control algorithm has been tested extensively in simulation and then implemented on a quadrotor UAV to demonstrate the performance of the closed loop system.
Robert Mahony - One of the best experts on this subject based on the ideXlab platform.
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a Terrain Following control approach for a vtol unmanned aerial vehicle using average optical flow
Autonomous Robots, 2010Co-Authors: Bruno Herisse, Tarek Hamel, Robert Mahony, Francois Xavier RussottoAbstract:This paper presents a nonlinear controller for Terrain Following of a vertical take-off and landing vehicle (VTOL). The VTOL vehicle is assumed to be a rigid body, equipped with a minimum sensor suite (camera, IMU and barometric altimeter) maneuvering over a textured rough Terrain made of a concatenation of planar surfaces. Assuming that the forward velocity is separately regulated to a desired value, the proposed control approach ensures Terrain Following and guarantees that the vehicle does not collide with the ground during the task. The proposed control acquires an optical flow from multiple spatially separate observation points, typically obtained via multiple cameras or non collinear directions in a unique camera. The proposed control algorithm has been tested extensively in simulation and then implemented on a quadrotor UAV to demonstrate the performance of the closed-loop system.
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A general optical flow based Terrain-Following strategy for a VTOL UAV using multiple views
Proceedings - IEEE International Conference on Robotics and Automation, 2010Co-Authors: Bruno Herisse, Sophie Oustrieres, Tarek Hamel, Robert Mahony, Francois Xavier RussottoAbstract:This paper presents a general approach for Terrain Following (including obstacle avoidance) of a vertical take-off and landing vehicle (VTOL) using multiple observation points. The VTOL vehicle is assumed to be a rigid body, equipped with a minimum sensor suite (camera, IMU and barometric altimeter), manoeuvering over a textured rough Terrain made of a concatenation of planar surfaces. Assuming that the forward velocity is separately regulated to a desired non-zero value, the proposed control approach ensures Terrain Following and guarantees the vehicle does not collide with obstacles during the task. The proposed control acquires an optical flow from multiple spatially separate observation points, typically obtained via multiple cameras or non collinear directions in a unique camera. The proposed control algorithm has been tested extensively in simulation and then implemented on a quadrotor UAV to demonstrate the performance of the closed loop system.
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Terrain Following using wide field optic flow
International Conference on Robotics and Automation, 2010Co-Authors: Evan Slatyer, Robert Mahony, Peter CorkeAbstract:Wall and Terrain Following is a challenging problem for small, fast, and fragile robot vehicles. This paper presents a robust algorithm based on wide field integration of optic flow. Solutions for two dimensional and three dimensional wall Following is provided for vehicles with non-holonomic velocity constraints that ensure that the focus of expansion of the flow field is known. The potential of the proposed algorithm is demonstrated in a simulation environment.
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a nonlinear Terrain Following controller for a vtol unmanned aerial vehicle using translational optical flow
International Conference on Robotics and Automation, 2009Co-Authors: Bruno Herisse, Tarek Hamel, Robert Mahony, Francois Xavier RussottoAbstract:This paper presents a nonlinear controller for Terrain Following of a vertical take-off and landing vehicle (VTOL). The VTOL vehicle is assumed to be a rigid body, equipped with a minimum sensor suite (camera and IMU) along with a measure of the forward speed from another sensor such as global positioning system, maneuvering over a textured Terrain made of planar surfaces. Assuming that the forward velocity is separately set to a desired value, the proposed control approach ensures Terrain Following and guaranties the vehicle does not collide with the ground during the task. The proposed control acquires an optical flow from three spatially separate observation points, typically obtained via three cameras or three non collinear directions in a unique camera. The proposed control algorithm has been tested extensively in simulation and then implemented on a quadrotor UAV to demonstrate the performance of the closed loop system.
Tarek Hamel - One of the best experts on this subject based on the ideXlab platform.
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a Terrain Following control approach for a vtol unmanned aerial vehicle using average optical flow
Autonomous Robots, 2010Co-Authors: Bruno Herisse, Tarek Hamel, Robert Mahony, Francois Xavier RussottoAbstract:This paper presents a nonlinear controller for Terrain Following of a vertical take-off and landing vehicle (VTOL). The VTOL vehicle is assumed to be a rigid body, equipped with a minimum sensor suite (camera, IMU and barometric altimeter) maneuvering over a textured rough Terrain made of a concatenation of planar surfaces. Assuming that the forward velocity is separately regulated to a desired value, the proposed control approach ensures Terrain Following and guarantees that the vehicle does not collide with the ground during the task. The proposed control acquires an optical flow from multiple spatially separate observation points, typically obtained via multiple cameras or non collinear directions in a unique camera. The proposed control algorithm has been tested extensively in simulation and then implemented on a quadrotor UAV to demonstrate the performance of the closed-loop system.
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A general optical flow based Terrain-Following strategy for a VTOL UAV using multiple views
Proceedings - IEEE International Conference on Robotics and Automation, 2010Co-Authors: Bruno Herisse, Sophie Oustrieres, Tarek Hamel, Robert Mahony, Francois Xavier RussottoAbstract:This paper presents a general approach for Terrain Following (including obstacle avoidance) of a vertical take-off and landing vehicle (VTOL) using multiple observation points. The VTOL vehicle is assumed to be a rigid body, equipped with a minimum sensor suite (camera, IMU and barometric altimeter), manoeuvering over a textured rough Terrain made of a concatenation of planar surfaces. Assuming that the forward velocity is separately regulated to a desired non-zero value, the proposed control approach ensures Terrain Following and guarantees the vehicle does not collide with obstacles during the task. The proposed control acquires an optical flow from multiple spatially separate observation points, typically obtained via multiple cameras or non collinear directions in a unique camera. The proposed control algorithm has been tested extensively in simulation and then implemented on a quadrotor UAV to demonstrate the performance of the closed loop system.
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a nonlinear Terrain Following controller for a vtol unmanned aerial vehicle using translational optical flow
International Conference on Robotics and Automation, 2009Co-Authors: Bruno Herisse, Tarek Hamel, Robert Mahony, Francois Xavier RussottoAbstract:This paper presents a nonlinear controller for Terrain Following of a vertical take-off and landing vehicle (VTOL). The VTOL vehicle is assumed to be a rigid body, equipped with a minimum sensor suite (camera and IMU) along with a measure of the forward speed from another sensor such as global positioning system, maneuvering over a textured Terrain made of planar surfaces. Assuming that the forward velocity is separately set to a desired value, the proposed control approach ensures Terrain Following and guaranties the vehicle does not collide with the ground during the task. The proposed control acquires an optical flow from three spatially separate observation points, typically obtained via three cameras or three non collinear directions in a unique camera. The proposed control algorithm has been tested extensively in simulation and then implemented on a quadrotor UAV to demonstrate the performance of the closed loop system.
Gunther Zangl - One of the best experts on this subject based on the ideXlab platform.
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extending the numerical stability limit of Terrain Following coordinate models over steep slopes
Monthly Weather Review, 2012Co-Authors: Gunther ZanglAbstract:AbstractTo extend the numerical stability limit over steep slopes, a truly horizontal pressure-gradient discretization based on the ideas formulated by Mahrer in the 1980s has been developed. Conventionally, the pressure gradient is evaluated in the Terrain-Following coordinate system, which necessitates a metric correction term that is prone to numerical instability if the height difference between adjacent grid points is much larger than the vertical layer spacing. The alternative way pursued here is to reconstruct the pressure gradient at auxiliary points lying at the same height as the target point on which the velocity is defined. This is accomplished via a second-order Taylor-series expansion in this work, using the hydrostatic approximation to transform the second derivatives into first derivatives to facilitate second-order accurate discretization in the presence of strong vertical grid stretching. Moreover, a reformulated lower boundary condition is used that avoids the extrapolation of vertical ...
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an improved method for computing horizontal diffusion in a sigma coordinate model and its application to simulations over mountainous topography
Monthly Weather Review, 2002Co-Authors: Gunther ZanglAbstract:Abstract A set of modifications is presented to reduce the unphysical impact of horizontal diffusion in numerical models with a Terrain-Following sigma-coordinate system. At model levels sufficiently far away from the ground, vertical interpolation is used to compute diffusion truly horizontally when the coordinate surfaces are sloping. Close to the ground, where truly horizontal computation of diffusion is not everywhere possible without intersecting the topography, a combination of one-sided truly horizontal diffusion and orography-adjusted diffusion along the sigma surfaces is used for most of the variables. The latter means that the diffusion coefficient is reduced strongly when the grid points involved in the computation of horizontal diffusion are located at greatly different heights. For temperature, one-sided horizontal diffusion is not used because it damps the slope wind circulation in an unphysical way. However, a temperature gradient correction is applied to the Terrain-Following part of the t...