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Full-Text Articles in Engineering
Vision-Based Target Localization From A Fixed-Wing Miniature Air Vehicle, Joshua D. Redding, Timothy W. Mclain, Randal W. Beard, Clark N. Taylor
Vision-Based Target Localization From A Fixed-Wing Miniature Air Vehicle, Joshua D. Redding, Timothy W. Mclain, Randal W. Beard, Clark N. Taylor
Faculty Publications
This paper presents a method for localizing a ground-based object when imaged from a small fixed-wing unmanned aerial vehicle (UAV). Using the pixel location of the target in an image, with measurements of UAV position and attitude, and camera pose angles, the target is localized in world coordinates. This paper presents a study of possible error sources and localization sensitivities to each source. The localization method has been implemented and experimental results are presented demonstrating the localization of a target to within 11 m of its known location.
Forest Fire Monitoring Using Multiple Unmanned Air Vehicles, Timothy Mclain, Randal W. Beard, Ryan S. Holt, Joseph W. Egbert, Justin M. Bradley, Clark N. Taylor
Forest Fire Monitoring Using Multiple Unmanned Air Vehicles, Timothy Mclain, Randal W. Beard, Ryan S. Holt, Joseph W. Egbert, Justin M. Bradley, Clark N. Taylor
Faculty Publications
The ability to gather and process information on the condition of forest fires is essential to fighting the fires in a cost-effective, safe, and efficient manner. While high-altitude, long-endurance (HALE) unmanned air vehicles (UAVs) are currently used for fire surveillance; they are an expensive and scarce resource. As a proposed alternative, low-altitude, short-endurance (LASE) UAVs offer lower costs, quicker response times, and high- resolution information. In recent years, advances in solid-state sensor and autopilot technology have made LASE UAVs a feasible alternative. This paper overviews a current research project conducted by Brigham Young University and NASA Ames. In the project, …
Learning Real-Time A* Path Planner For Unmanned Air Vehicle Target Sensing, Jason K. Howlett, Timothy W. Mclain, Michael A. Goodrich
Learning Real-Time A* Path Planner For Unmanned Air Vehicle Target Sensing, Jason K. Howlett, Timothy W. Mclain, Michael A. Goodrich
Faculty Publications
This paper presents a path planner for sensing closely-spaced targets from a fixed-wing unmanned air vehicle (UAV) having a specified sensor footprint. The planner is based on the learning real-time A* (LRTA*) search algorithm and produces dynamically feasible paths that accomplish the sensing objectives in the shortest possible distance. A tree of candidate paths that span the area of interest is created by assembling primitive turn and straight sections of a specified step size in a sequential fashion from the starting position of the UAV. An LRTA* search of the tree produces feasible paths any time during its execution and …
Static And Dynamic Obstacle Avoidance For Miniature Air Vehicles, Jeffery Brian Saunders, Brandon Call, Andrew Curtis, Randal W. Beard, Timothy W. Mclain
Static And Dynamic Obstacle Avoidance For Miniature Air Vehicles, Jeffery Brian Saunders, Brandon Call, Andrew Curtis, Randal W. Beard, Timothy W. Mclain
Faculty Publications
Small unmanned air vehicles are limited in sensor weight and power such that detection and avoidance of unknown obstacles during flight is difficult. This paper presents a low power low weight method of detection using a laser range finder. In addition, a rapidly-exploring random tree algorithm to generate waypoint paths around obstacles known a priori is presented, and a dynamic geometric algorithm to generate paths around detected obstacles is derived. The algorithms are demonstrated in simulation and in flight tests on a fixed-wing miniature air vehicle (MAV).
Decentralized Perimeter Surveillance Using A Team Of Uavs, Timothy Mclain, Randal W. Beard, Derek Kingston, Ryan S. Holt, David W. Casbeer
Decentralized Perimeter Surveillance Using A Team Of Uavs, Timothy Mclain, Randal W. Beard, Derek Kingston, Ryan S. Holt, David W. Casbeer
Faculty Publications
This paper poses the cooperative perimeter-surveillance problem and offers a decentralized solution that accounts for perimeter growth (expanding or contracting) and insertion/deletion of team members. By identifying and sharing the critical coordination information and by exploiting the known communication topology, only a small communication range is required for accurate performance. Simulation and hardware results are presented that demonstrate the applicability of the solution.
Forest Fire Monitoring With Multiple Small Uavs, David W. Casbeer, Randal W. Beard, Timothy W. Mclain, Sai-Ming Li, Raman K. Mehra
Forest Fire Monitoring With Multiple Small Uavs, David W. Casbeer, Randal W. Beard, Timothy W. Mclain, Sai-Ming Li, Raman K. Mehra
Faculty Publications
Frequent and detailed updates of the development of a forest fire are essential for effective and safe fire fighting. Since a forest fire is typically inaccessible by ground vehicles due to mountainous terrain, small Unmanned Air Vehicles (UAVs) are emerging as a promising solution to the problem of monitoring large forest fires. In this paper we present an effective path planning algorithm for a UAV utilizing infrared images that are collected on-board in realtime. In order to demonstrate the effectiveness of our path planning algorithm in realistic scenarios, we implemented the forest fire propagation model EMBYR to simulate the time …
Autonomous Vehicle Technologies For Small Fixed-Wing Uavs, Randal Beard, Derek Kingston, Morgan Quigley, Deryl Snyder, Reed Christiansen, Walt Johnson, Timothy Mclain, Michael A. Goodrich
Autonomous Vehicle Technologies For Small Fixed-Wing Uavs, Randal Beard, Derek Kingston, Morgan Quigley, Deryl Snyder, Reed Christiansen, Walt Johnson, Timothy Mclain, Michael A. Goodrich
Faculty Publications
The objective of this paper is to describe the design and implementation of a small semi-autonomous fixed-wing unmanned air vehicle. In particular we describe the hardware and software architectures used in the design. We also describe a low weight, low cost autopilot developed at Brigham Young University and the algorithms associated with the autopilot. Novel PDA and voice interfaces to the UAV are described. In addition, we overview our approach to real-time path planning, trajectory generation, and trajectory tracking. The paper is augmented with movie files that demonstrate the functionality of the UAV and its control software.
Initial Experiments In The Cooperative Control Of Unmanned Air Vehicles, Derek R. Nelson, Timothy W. Mclain, Reed S. Christiansen, Randal W. Beard, David Johansen
Initial Experiments In The Cooperative Control Of Unmanned Air Vehicles, Derek R. Nelson, Timothy W. Mclain, Reed S. Christiansen, Randal W. Beard, David Johansen
Faculty Publications
This paper addresses cooperative control for a team of unmanned air vehicles (UAVs). Specifically, a team of three small UAVs is controlled to perform a cooperative timing mission. Starting at loiter locations distributed around the periphery of a 2 km square battle area, the UAVs cooperatively plan paths to arrive at a target at the center of the battle area in sequence at 10 sec intervals. Cooperative path planning is performed using the methodology of coordination variables and coordination functions. Coordination and waypoint path planning are centralized on a ground station computer. Experiments have been performed using BYU’s fleet of …
Unmanned Air Vehicle Testbed For Cooperative Control Experiments, Timothy W. Mclain, Randal W. Beard
Unmanned Air Vehicle Testbed For Cooperative Control Experiments, Timothy W. Mclain, Randal W. Beard
Faculty Publications
This paper describes the MAGICC Lab unmanned air vehicle (UAV) testbed at Brigham Young University. Motivation for pursuing experimental research with UAVs is given as well as a historical perspective of the UAV testbed development. Lessons learned through the development and use of the testbed over the past several years are summarized.
Coordinated Uav Target Assignment Using Distributed Tour Calculation, David H. Walker, Timothy W. Mclain, Jason K. Kowlett
Coordinated Uav Target Assignment Using Distributed Tour Calculation, David H. Walker, Timothy W. Mclain, Jason K. Kowlett
Faculty Publications
In this chapter a method for assigning unmanned aerial vehicle agents to targets through the use of preplanned vehicle tours is presented. Assignments are based on multi-target tours that consider the spread of the targets and the sensor capabilities of the vehicles. In this way, the individual agents and the team as a whole make better use of team resources and improve team cooperation. Planning and assignments are accomplished in reasonable computational time through the use of heuristics to reduce the problem size.
Multiple Uav Cooperative Search Under Collision Avoidance And Limited Range Communication Constraints, Randal W. Beard, Timothy W. Mclain
Multiple Uav Cooperative Search Under Collision Avoidance And Limited Range Communication Constraints, Randal W. Beard, Timothy W. Mclain
Faculty Publications
This paper focuses on the problem of cooperatively searching, using a team of unmanned air vehicles (UAVs), an area of interest that contains regions of opportunity and regions of potential hazard. The objective of the UAV team is to visit as many opportunities as possible, while avoiding as many hazards as possible. To enable cooperation, the UAVs are constrained to stay within communication range of one another. Collision avoidance is also required. Algorithms for team-optimal and individually-optimal/team-suboptimal solutions are developed and their computational complexity compared. Simulation results demonstrating the feasibility of the cooperative search algorithms are presented.
Autonomous Vehicle Technologies For Small Fixed Wing Uavs, Derek B. Kingston, Randal Beard, Timothy Mclain, Michael Larsen, Wei Ren
Autonomous Vehicle Technologies For Small Fixed Wing Uavs, Derek B. Kingston, Randal Beard, Timothy Mclain, Michael Larsen, Wei Ren
Faculty Publications
Autonomous unmanned air vehicle flight control systems require robust path generation to account for terrain obstructions, weather, and moving threats such as radar, jammers, and unfriendly aircraft. In this paper, we outline a feasible, hierarchal approach for real-time motion planning of small autonomous fixed-wing UAVs. The approach divides the trajectory generation into four tasks: waypoint path planning, dynamic trajectory smoothing, trajectory tracking, and low-level autopilot compensation. The waypoint path planner determines the vehicle's route without regard for the dynamic constraints of the vehicle. This results in a significant reduction in the path search space, enabling the generation of complicated paths …
Learning Real-Time A* Path Planner For Sensing Closely-Spaced Targets From An Aircraft, Jason K. Howlett, Michael A. Goodrich, Timothy W. Mclain
Learning Real-Time A* Path Planner For Sensing Closely-Spaced Targets From An Aircraft, Jason K. Howlett, Michael A. Goodrich, Timothy W. Mclain
Faculty Publications
This work develops an any-time path planner, based on the learning real-time A* (LRTA*) search, for generating flyable paths that allow an aircraft with a specified sensor footprint to sense a group of closely-spaced targets. The LRTA* algorithm searches a tree of flyable paths for the branch that accomplishes the desired objectives in the shortest distance. The tree of paths is created by assembling primitive turn and straight sections of a specified step size. The operating parameters for the LRTA* search directly influence the running time and path-length performance of the search. A modified LRTA* search is presented that terminates …
Cooperative Path Planning For Timing Critical Missions, Timothy W. Mclain, Randal W. Beard
Cooperative Path Planning For Timing Critical Missions, Timothy W. Mclain, Randal W. Beard
Faculty Publications
This paper presents a cooperative path planning approach for teams of vehicles operating under timing constraints. A cooperative control approach based on coordination variables and coordination functions is introduced and applied to cooperative timing problems. Three types of timing constraints are considered: simultaneous arrival, tight sequencing, and loose sequencing. Simulation results demonstrating the approach are presented.
Experimental Demonstration Of Multiple Robot Cooperative Target Intercept, Timothy W. Mclain, Randal W. Beard, Jed M. Kelsey
Experimental Demonstration Of Multiple Robot Cooperative Target Intercept, Timothy W. Mclain, Randal W. Beard, Jed M. Kelsey
Faculty Publications
This paper presents experimental results for the simultaneous intercept of preassigned targets by a team of mobile robots. The robots are programmed to mimic the dynamic behavior of unmanned air vehicles in constant-altitude flight. In proceeding to their targets, robots must avoid both known static threats and pop-up threats. An overview of the cooperative control strategy followed is given, as well as a description of the robot hardware and software used. Experimental results demonstrating simultaneous intercept of targets by the robot team are presented.
Autonomous Hierarchical Control Of Multiple Unmanned Combat Air Vehicles (Ucavs), Timothy Mclain, Randal W. Beard, Sai-Ming Li, Jovan D. Boskovic, Sanjeev Seereeram, Ravi Prasanth, Jayesh Amin, Raman K. Mehra
Autonomous Hierarchical Control Of Multiple Unmanned Combat Air Vehicles (Ucavs), Timothy Mclain, Randal W. Beard, Sai-Ming Li, Jovan D. Boskovic, Sanjeev Seereeram, Ravi Prasanth, Jayesh Amin, Raman K. Mehra
Faculty Publications
In this paper we present a hierarchical control scheme that enables multiple UCAVs to achieve demanding missions in hostile environments autonomously. The objective is to use a swarm of UCAVs for a SEAD type mission: fly the UCAVs in a formation to an enemy territory populated with different kinds of threats, collect enemy information or destroy certain targets, and return to the base, all without human intervention. The scheme is an integration of four distinct components, including: (1) high level Voronoi diagram based path planner to avoid static threats; (2) low level path planner to avoid popup threats; (3) differential …
Spline Based Path Planning For Unmanned Air Vehicles, Kevin B. Judd, Timothy W. Mclain
Spline Based Path Planning For Unmanned Air Vehicles, Kevin B. Judd, Timothy W. Mclain
Faculty Publications
A trajectory planning scheme that generates feasible flight routes for an unmanned air vehicle (UAV) is developed. A preliminary path is generated from a Voronoi diagram based on threat locations. This path consists of a series of straight-line segments that cannot be followed exactly by the UAV. Using a series of cubic splines to connect these straight-line segments, this path is refined into an optimum path that is flyable by the UAV. Utilizing a decomposition strategy, both the full path (coarse detail) to the target and the proximate optimum path (fine detail) near the UAV can be quickly computed. The …
Cooperative Control Of Uav Rendezvous, Timothy W. Mclain, Phillip R. Chandler, Steven Rasmussen, Meir Pachter
Cooperative Control Of Uav Rendezvous, Timothy W. Mclain, Phillip R. Chandler, Steven Rasmussen, Meir Pachter
Faculty Publications
The cooperative control of timing and synchronization of tasks of multiple unmanned air vehicles (UAVs) represents a valuable capability for a wide range of potential multi-UAV missions. This research addresses the specific problem of cooperative rendezvous in which multiple UAVs are to arrive at their targets simultaneously. The development of a rendezvous manager state machine and a cooperative control decomposition approach are described. Simulation results demonstrating the feasibility of the approach are presented.
Trajectory Planning For Coordinated Rendezvous Of Unmanned Air Vehicles, Timothy W. Mclain, Randal W. Beard
Trajectory Planning For Coordinated Rendezvous Of Unmanned Air Vehicles, Timothy W. Mclain, Randal W. Beard
Faculty Publications
A trajectory generation strategy that facilitates the coordination of multiple unmanned air vehicles is developed. Of particular interest is the planning of threat-avoiding trajectories that result in the simultaneous arrival of multiple UAVs at their targets. In this approach, paths to the target are modeled using the physical analogy of a chain. A unique strength of the planning approach is the ability to specify or alter the path length by adding or subtracting links from the chain. Desirable paths to the target are obtained by simulating the dynamics of the chain where threats apply repulsive forces to the chain and …