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Articles 1 - 8 of 8
Full-Text Articles in Mechanical Engineering
Reactive Motion Planning Of Autonomous Vehicles In 3-Dimensional Environments Using Collision And Rendezvous Cones, Kashish Dhal
Reactive Motion Planning Of Autonomous Vehicles In 3-Dimensional Environments Using Collision And Rendezvous Cones, Kashish Dhal
Mechanical and Aerospace Engineering Dissertations
This dissertation presents a collision cone/rendezvous cone-based approach for reactive motion planning in three-dimensional dynamic environments. Collision avoidance is fundamental to robot motion planning. In dynamic environments, the path and velocities of obstacles are not known a-priori, and hence it is a common practice to use reactive planners. Reactive planners should be computationally inexpensive because they need to act fast to avoid potential collisions. To reduce the computational load, a majority of motion planning algorithms model the shapes of the robots and obstacles as a circle/sphere. However, when the objects are elongated more in one direction than another, the spherical …
Fixed Wing Aircraft Collision Avoidance Using Collision Cone Theory, Andrew T. Iii Beary
Fixed Wing Aircraft Collision Avoidance Using Collision Cone Theory, Andrew T. Iii Beary
Mechanical and Aerospace Engineering Theses
This thesis develops the guidance and control components of an aircraft collision avoidance system, using a collision cone-based approach. These guidance and control laws are developed by considering the nonlinear relative kinematic equations of the aircraft that are on a collision course, as well as the nonlinear flight dynamics of the aircraft performing the collision avoidance maneuver. The longitudinal and lateral-directional axes of the aircraft are considered separately. The developed guidance and control laws are subsequently integrated with the nonlinear aircraft dynamics in a MATLAB/Simulink framework, and simulations performed to demonstrate the working of the overall system.
Integration Of A Complete Detect And Avoid System For Small Unmanned Aircraft Systems, Jared Kevin Wikle
Integration Of A Complete Detect And Avoid System For Small Unmanned Aircraft Systems, Jared Kevin Wikle
Theses and Dissertations
For unmanned aircraft systems to gain full access to the National Airspace System (NAS), they must have the capability to detect and avoid other aircraft. This research focuses on the development of a detect-and-avoid (DAA) system for small unmanned aircraft systems. To safely avoid another aircraft, an unmanned aircraft must detect the intruder aircraft with ample time and distance. Two analytical methods for finding the minimum detection range needed are described. The first method, time-based geometric velocity vectors (TGVV), includes the bank-angle dynamics of the ownship while the second, geometric velocity vectors (GVV), assumes an instantaneous bank-angle maneuver. The solution …
Autonomous Quadrotor Collision Avoidance And Destination Seeking In A Gps-Denied Environment, Thomas C. Kirven
Autonomous Quadrotor Collision Avoidance And Destination Seeking In A Gps-Denied Environment, Thomas C. Kirven
Theses and Dissertations--Mechanical Engineering
This thesis presents a real-time autonomous guidance and control method for a quadrotor in a GPS-denied environment. The quadrotor autonomously seeks a destination while it avoids obstacles whose shape and position are initially unknown. We implement the obstacle avoidance and destination seeking methods using off-the-shelf sensors, including a vision-sensing camera. The vision-sensing camera detects the positions of points on the surface of obstacles. We use this obstacle position data and a potential-field method to generate velocity commands. We present a backstepping controller that uses the velocity commands to generate the quadrotor's control inputs. In indoor experiments, we demonstrate that the …
Development Of A Sense And Avoid System For Small Unmanned Aircraft Systems, Robert Andrew Klaus
Development Of A Sense And Avoid System For Small Unmanned Aircraft Systems, Robert Andrew Klaus
Theses and Dissertations
Unmanned aircraft systems (UAS) represent the future of modern aviation. Over the past 10 years their use abroad by the military has become commonplace for surveillance and combat. Unfortunately, their use at home has been far more restrictive. Due to safety and regulatory concerns, UAS are prohibited from flying in the National Airspace System without special authorization from the FAA. One main reason for this is the lack of an on-board pilot to "see and avoid" other air traffic and thereby maintain the safety of the skies. Development of a comparable capability, known as "Sense and Avoid" (SAA), has therefore …
Android App For General Aviation Ground Collision Avoidance, Corey Taylor Christiansen, Timothy Justin Dascomb, John Preston Cook
Android App For General Aviation Ground Collision Avoidance, Corey Taylor Christiansen, Timothy Justin Dascomb, John Preston Cook
Mechanical Engineering
This project used ground collision avoidance algorithms developed by NASA's Dryden Flight Research Center to create an Android application that could be used by general aviation pilots. The application uses GPS and accelerometer data to calculate future trajectories and checks them against a terrain elevation map of the United States stored on the SD card. X-Plane, a flight simulator, was used for project testing.
Haptic Collision Avoidance For A Remotely Operated Quadrotor Uav In Indoor Environments, Adam M. Brandt
Haptic Collision Avoidance For A Remotely Operated Quadrotor Uav In Indoor Environments, Adam M. Brandt
Theses and Dissertations
A quadrotor is an omnidirectional unmanned air vehicle that is suitable for indoor flight because of its ability to hover and maneuver in confined spaces. The remote operation of this type of vehicle is difficult due to a lack of sensory perception; typically, the view from the onboard camera is the only information transmitted to the pilot. This thesis proposes using force feedback exerted by the command input device on the hand of the pilot to assist in avoiding collisions while navigating in indoor environments. Five candidate algorithms are presented for calculating the forces to be felt by the pilot …
Cooperative Uav Formation Flying With Obstacle/Collision Avoidance, Xiaohua Wang, Vivek Yadav, S. N. Balakrishnan
Cooperative Uav Formation Flying With Obstacle/Collision Avoidance, Xiaohua Wang, Vivek Yadav, S. N. Balakrishnan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Navigation problems of unmanned air vehicles (UAVs) flying in a formation in a free and an obstacle-laden environment are investigated in this brief. when static obstacles popup during the flight, the UAVs are required to steer around them and also avoid collisions between each other. In order to achieve these goals, a new dual-mode control strategy is proposed: a “safe mode” is defined as an operation in an obstacle-free environment and a “danger mode” is activated when there is a chance of collision or when there are obstacles in the path. Safe mode achieves global optimization because the dynamics of …