Download or read book Real time Trajectory Design for UAVs Using RHC written by Yoshiaki Kuwata and published by . This book was released on 2003 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Real time Optimal Trajectory Smoothing for Unmanned Aerial Vehicle in Three Dimensions written by Saideepthi Malisetty and published by . This book was released on 2011 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents a dynamically feasible and real-time trajectory path generation algorithm for unmanned aerial vehicles (UAVs) flying through a sequence of a random N number of waypoints (WPs) in three dimensions. Pontryagin's minimum principle was used to show that the straight-line path segments connecting the sequence of waypoints are time optimal [1]. An algorithm was designed so that the total trajectory path length of a UAV is approximately equal to the straight-line path of the waypoints. The trajectory path obtained was also compared with the one-circle method, and it was found that the proposed method has less path length. Issues related to this algorithm are explained in detail. Simulation results show the efficiency of the method.

Download or read book Zwen und dreissig Artickel die allgemeinen Religion und Glauben belangend von den Theologen der hohen schul zu L ven gantz newlich aussgangen written by and published by . This book was released on 1545 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Theory and Algorithms for Cooperative Systems written by Don A. Grundel and published by World Scientific. This book was released on 2004 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past several years, cooperative control and optimization have increasingly played a larger and more important role in many aspects of military sciences, biology, communications, robotics, and decision making. At the same time, cooperative systems are notoriously difficult to model, analyze, and solve OCo while intuitively understood, they are not axiomatically defined in any commonly accepted manner. The works in this volume provide outstanding insights into this very complex area of research. They are the result of invited papers and selected presentations at the Fourth Annual Conference on Cooperative Control and Optimization held in Destin, Florida, November 2003. This book has been selected for coverage in: . OCo Index to Scientific & Technical Proceedings- (ISTP- / ISI Proceedings). OCo Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings). OCo CC Proceedings OCo Engineering & Physical Sciences. Contents: Mesh Stability in Formation of Distributed Systems (C Ashokkumar et al.); On the Performance of Heuristics for Broadcast Scheduling (C Commander et al.); Coupled Detection Rates: An Introduction (D Jeffcoat); Decentralized Receding Horizon Control for Multiple UAVs (Y Kuwata & J How); Multitarget Sensor Management of Dispersed Mobile Sensors (R Mahler); K-Means Clustering Using Entropy Minimization (A Okafor & P Pardalos); Possibility Reasoning and the Cooperative Prisoner''s Dilemma (H Pfister & J Walls); Coordinating Very Large Groups of Wide Area Search Munitions (P Scerri et al.); A Vehicle Following Methodology for UAV Formations (S Spry et al.); Decentralized Optimization via Nash Bargaining (S Waslander et al.); and other papers. Readership: Graduate students and researchers in optimization and control, computer science and engineering."

Download or read book Trajectory Optimization for Target Localization Using Small Unmanned Aerial Vehicles written by Sameera S. Ponda and published by . This book was released on 2008 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt: (cont.) The UAV trajectory optimization is performed for stationary targets, dynamic targets and multiple targets, for many different scenarios of vehicle motion constraints. The resulting trajectories show spiral paths taken by the UAV, which focus on increasing the angular separation between measurements and reducing the relative range to the target, thus maximizing the information provided by each measurement and improving the performance of the estimation. The main drawback of information based trajectory design is the dependence of the Fisher Information Matrix on the true target location. This issue is addressed in this project by executing simultaneous target location estimation and UAV trajectory optimization. Two estimation algorithms, the Extended Kalman Filter and the Particle Filter are considered, and the trajectory optimization is performed using the mean value of the target estimation in lieu of the true target location. The estimation and optimization algorithms run in sequence and are updated in real-time. The results show spiral UAV trajectories that increase filter convergence and overall estimation accuracy, illustrating the importance of information-based trajectory design for target localization using small UAVs.

Download or read book UAV Two dimensional Path Planning in Real time Using Fuzzy Logic written by Chelsea Sabo and published by . This book was released on 2011 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: There are a variety of scenarios in which the mission objectives rely on a UAV being capable of maneuvering in an environment containing obstacles in which there is little prior knowledge of the surroundings. In these situations, not only can these obstacles be dynamic, but sometimes there is no way to plan ahead of the mission to avoid them. Additionally, there are many situations in which it is desirable to send in an exploratory robot where the environment is dangerous/ contaminated and there is a great deal of uncertainty. These scenarios could either be too risky to send people or not available to humans. With an appropriate dynamic motion planning algorithm in these situations, robots or UAVs would be able to maneuver in any unknown and/or dynamic environment towards a target in real-time. An autonomous system that can handle these varying conditions rapidly and efficiently without failure is imperative to the future of unmanned aerial vehicle (UAV). This paper presents a methodology for two-dimensional path planning of a UAV using fuzzy logic. This approach is selected due to its ability to emulate human decision making and relative ease of implementation. The fuzzy inference system takes information in real time about obstacles (if within the agent's sensing range) and target location and outputs a change in heading angle and speed. The FL controller was validated for both simple (polygon obstacles in a sparse space) and complex environments (i.e. non-polygon obstacles, symmetrical/concave obstacles, dense environments, etc). Additionally, Monte Carlo testing was completed to evaluate the performance of the control method. Not only was the path traversed by the UAV often the exact path computed using an optimal method, the low failure rate makes the Fuzzy Logic Controller (FLC) feasible for exploration. The FLC showed only a total of 3% failure rate, whereas an Artificial Potential Field (APF) solution, a commonly used intelligent control method, had an average of 18% failure rate. Also, the APF method failed about 1/3 of the time for very dense environments (the FLC only had 5% failure rate). These results highlighted one of the advantages of the FLC method: its adaptability to additional rules while maintaining low control effort. Furthermore, the solutions showed superior results when compared to the APF solutions when compared to distance traversed. Overall, the FLC produced solutions that were on average only about 7.7% greater distance traveled (as opposed to 9.7% for the APF).

Download or read book Maneuver Design and Motion Planning for Agile Fixed wing UAVs written by Joshua Levin and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "In recognition of their broad scope of utility, recent years have seen a surge of interest in unmanned aerial vehicles (UAVs). As a result of technological advancements, UAVs have been rapidly expanding into the civilian marketplace. Many of the jobs UAVs have the potential to fill demand high levels of autonomy, and thus the state-of-the-art is constantly being pushed forward. Many such jobs require near-ground autonomous flight through obstacle-dense environments. Achieving proficiency in this regard requires agile motion, precise tracking performance, and efficient real-time planning.Many non-traditional UAV platforms have been designed to suit various applications. Agile fixed-wing UAVs represent one such class of vehicles. They are characterized by their high thrust-to-weight ratio, large control surfaces, low aspect ratios, and a powerful propeller slipstream (also known as propwash). While they were originally marketed towards remote control pilots, their design makes them inherently valuable for autonomous flight. The primary appeal of the design is that it allows for both efficient fixed-wing forward flying and agile maneuvering, e.g. stopping mid-flight. In this way, these UAVs begin to bridge the gap in utility between efficient fixed-wing vehicles, and agile rotorcraft. The broad objective of this thesis is to exploit the full maneuvering capabilities of agile fixed-wing UAVs for autonomous flight. The main topics covered are maneuver design, control, and motion planning. The thesis begins with a discussion of preliminary topics: an aircraft dynamics model, a feedback controller, and an optimization framework, all of which are utilized throughout the following sections of the thesis. Next, an investigation is performed to evaluate the significance of sideslip and propeller slipstream in extreme maneuvering with fixed-wing UAVs. We identify the cost, in terms of performance loss, if either of these two phenomena are not accounted for in maneuver design.In the following chapter, we propose a strategy for designing and controlling agile maneuvers that takes advantage of the aircraft's full flight envelope. Optimal and dynamically feasible trajectories are generated, along with their associated feedforward control laws. Combining the transient agile maneuvers with steady-state trim conditions, we formulate a maneuver space, i.e. a library of trajectories. The maneuver space acts as a hybrid representation of the vehicle's dynamics, and as such is useful for efficient real-time motion planning. This chapter also includes a description of a heuristic for transitioning between maneuvers, and a methodology for continuously parametrizing agile maneuvers.As a natural progression towards the ultimate goal of the thesis, the maneuver space is integrated into a real-time motion planner based on the Rapidly-Exploring Random Trees (RRT) algorithm. The planner is used to address the problem of generating a dynamically feasible motion plan to guide the aircraft to a desired goal through a highly-constrained, three-dimensional environment. For the purposes of this thesis, the environment is assumed to be known, and to only contain static obstacles. The planning framework is able to exploit the aircraft's full maneuvering capabilities, and couples well with a control system for effective trajectory tracking.To conclude the main body of the thesis, simulation and flight test results are presented and discussed. The flight tests are performed in two sets. First, to perform a number of agile maneuvers, in isolation and in series. The experiments validate the feasibility of the maneuvers, and test the efficacy of the proposed control system. The second set of tests validate the real-time motion planner. All experiments, including the real-time motion planning, are implemented using only the sensors and computers mounted on-board the UAV." --

Download or read book Optimal Guidance and Its Applications in Missiles and UAVs written by Shaoming He and published by Springer Nature. This book was released on 2020-05-13 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a comprehensive overview of the recent advances in the domain of optimal guidance, exploring the characteristics of various optimal guidance algorithms and their pros and cons. Optimal guidance is based on the concept of trajectory optimization, which minimizes the meaningful performance index while satisfying certain terminal constraints, and by properly designing the cost function the guidance command can serve as a desired pattern for a variety of mission objectives. The book allows readers to gain a deeper understanding of how optimal guidance law can be utilized to achieve different mission objectives for missiles and UAVs, and also explores the physical meaning and working principle of different new optimal guidance laws. In practice, this information is important in ensuring confidence in the performance and reliability of the guidance law when implementing it in a real-world system, especially in aerospace engineering where reliability is the first priority.

Download or read book Trajectory Generation for a Quadrotor Unmanned Aerial Vehicle written by Douglas Conover and published by . This book was released on 2018 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of multirotor unmanned aerial vehicles (UAVs) has seen substantial progression in the past decade. Trajectory generation and control has been a main focus in this domain, with methods that enable the performance of complex three-dimensional maneuvers through space. Efforts have been made to execute these maneuvers using concepts of nonlinear control and differential flatness. However, a lack of theory for the estimation of higher-order dérivatives of a multirotor UAV has prevented the experimental application of several of these techniques concentrated on trajectory control. This work firstly explores the existing control approach of sequential composition for the execution of quadrotor manoeuvres through narrow windows. This technique involves the combination of several theoretically simple controllers in sequence in order to produce a complex result. Experimental results conducted in the Mobile Robotics and Automated Systems Laboratory (MRASL) at Polytechnique demonstrate the validity of this approach, producing precise and repeatable manoeuvres through narrow windows. However, they also show the limitations of such a method in real world applications, notably its initial inaccuracy and lack of feasibility evaluation. This thesis then focuses on the development of a state-estimation architecture based on linear Kalman filter techniques in order to provide a real-time value of a quadrotor UAV's second and third derivatives (referred to as acceleration and jerk, respectively). Filters of different complexities are developed with the goal of incorporating all available system information into the resulting estimate. A full-state estimator is produced that uses a quadrotor's position and acceleration measurements as well as control inputs in order to be usable for feedback. A jerk-augmented controller based off of optimal control theory is then developed in order to validate this estimator. It is designed in such a way to use the UAV's jerk, acceleration, velocity and position as design parameters and to be unstable without feedback in each of these terms. Tests are conducted in order to examine the performance of both the estimator and controller. Firstly, the quadrotor is commanded to track various reference inputs in 3D space to ensure its stability. The controller tracks these references very closely to simulated responses. The controller is then asked to follow a changing reference in order to evaluate the precision of the developed estimator. Results show that the real-time estimation of the jerk follows offline values adequately. To the best of our knowledge, this is the first application to implement the feedback of a multirotor UAV's jerk in real-world experimentation.

Download or read book UAV Based Remote Sensing Volume 2 written by Felipe Gonzalez Toro and published by MDPI. This book was released on 2018-04-27 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "UAV-Based Remote Sensing" that was published in Sensors

Download or read book Online Optimal Obstacle Avoidance for Rotary wing Autonomous Unmanned Aerial Vehicles written by Keeryun Kang and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents an integrated framework for online obstacle avoidance of rotary-wing unmanned aerial vehicles (UAVs), which can provide UAVs an obstacle field navigation capability in a partially or completely unknown obstacle-rich environment. The framework is composed of a LIDAR interface, a local obstacle grid generation, a receding horizon (RH) trajectory optimizer, a global shortest path search algorithm, and a climb rate limit detection logic. The key feature of the framework is the use of an optimization-based trajectory generation in which the obstacle avoidance problem is formulated as a nonlinear trajectory optimization problem with state and input constraints over the finite range of the sensor. This local trajectory optimization is combined with a global path search algorithm which provides a useful initial guess to the nonlinear optimization solver. Optimization is the natural process of finding the best trajectory that is dynamically feasible, safe within the vehicle's flight envelope, and collision-free at the same time. The optimal trajectory is continuously updated in real time by the numerical optimization solver, Nonlinear Trajectory Generation (NTG), which is a direct solver based on the spline approximation of trajectory for dynamically flat systems. In fact, the overall approach of this thesis to finding the optimal trajectory is similar to the model predictive control (MPC) or the receding horizon control (RHC), except that this thesis followed a two-layer design; thus, the optimal solution works as a guidance command to be followed by the controller of the vehicle. The framework is implemented in a real-time simulation environment, the Georgia Tech UAV Simulation Tool (GUST), and integrated in the onboard software of the rotary-wing UAV test-bed at Georgia Tech. Initially, the 2D vertical avoidance capability of real obstacles was tested in flight. Then the flight test evaluations were extended to the benchmark tests for 3D avoidance capability over the virtual obstacles, and finally it was demonstrated on real obstacles located at the McKenna MOUT site in Fort Benning, Georgia. Simulations and flight test evaluations demonstrate the feasibility of the developed framework for UAV applications involving low-altitude flight in an urban area.

Download or read book Real Time Trajectory Generation for Autonomous Nonlinear Flight Systems written by and published by . This book was released on 2006 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unmanned aerial vehicle and smart munition systems need robust, real-time path generation and guidance systems to avoid terrain obstructions, navigate in hazardous weather conditions, and react to mobile threats such as radar, jammers, and unfriendly aircraft. In Phase 1 of this STTR project, real-time path planning and trajectory generation techniques for two dimensional flight were developed and demonstrated in software simulation. In Phase 2 these algorithms were refined, extended and were demonstrated in flight on a unique low-cost micro-air vehicle with a payload which included three optical flow sensors, a laser ranger, and a video camera. This report is a comprehensive technical summary of the significant work completed in Phase 2 to enable development of autonomous flight control systems which are capable of accomplishing the complex task of path and trajectory planning in dynamic and uncertain environments.

Download or read book Autonomous Routing of Unmanned Aerial Vehicle UAV Relays to Mimic Optimal Trajectories in Real Time written by Jeremy P. Boire (CAPT, USAF.) and published by . This book was released on 2011 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Implementation Issues of Real time Trajectory Generation on Small UAVs written by Derek Bastian Kingston and published by . This book was released on 2004 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: The transition from a mathematical algorithm to a physical hardware implementation is non-trivial. This thesis discusses the issues involved in the transition from the theory of real-time trajectory generation all the way through a hardware experiment. Documentation of the validation process as well as modifications to the existing theory as a result of hardware testing are treated at length. The results of hardware experimentation show that trajectory generation can be done in real-time in a manner facilitating coordination of multiple small UAVs.

Download or read book Trajectory Planning for Flights in Multiagent and Dynamic Environments written by Jesus Tordesillas Torres and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: While efficient and fast trajectory planners in static worlds have been extensively proposed for UAVs (Unmanned Aerial Vehicles), a 3D real-time planner for environments with static obstacles, dynamic obstacles, and other planning agents still remains an open problem. The dynamic nature of these environments demands high replanning rates, making this problem especially hard on computationally limited platforms. Existing state-of-the-art planners reduce the computational complexity at the expense of more conservative results by relying on three main simplifications or assumptions: First, the collision avoidance constraints are imposed using the Bernstein and B-Spline polynomial bases, which do not tightly enclose a given interval of a polynomial trajectory. Second, multiagent planners usually make centralized and/or synchronized computation assumptions, which lead to poor scalability with the number of agents or can degrade the overall performance. Finally, position and yaw are decoupled when optimizing perception-aware trajectories, which produces highly conservative results. This thesis addresses the aforementioned limitations with the following contributions: First, it presents the MINVO basis, a polynomial basis that generates the simplex with minimum volume enclosing a polynomial curve, therefore reducing the conservativeness in the obstacle avoidance constraints. Leveraging the MINVO basis, this thesis then proposes a tractable way to avoid dynamic obstacles by imposing linear separability constraints between the polyhedral enclosures of the intervals of the trajectories. This is then extended to multiagent scenarios, and a decentralized and asynchronous obstacle avoidance algorithm among many replanning agents is presented. Real-time perception-aware planning is achieved by implicitly imposing the underactuated dynamics of the UAV through the Hopf fibration while jointly optimizing the full pose. Finally, a reduction of two orders of magnitude in the computation time is obtained by learning a policy that imitates the optimization-based planner. These proposed contributions are extensively evaluated in simulation, showing up to 32 agents planning in real time, and in real-world experiments, showcasing flights up to 5.8 m/s in unknown dynamic environments with only onboard computation.

Download or read book Trajectory Optimization with Detection Avoidance for Visually Identifying an Aircraft written by Leonard Nathaniel Wholey and published by . This book was released on 2005 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unmanned aerial vehicles (UAVs) play an essential role for the US Armed Forces by performing missions deemed as "dull, dirty and dangerous" for a pilot. As the capability of UAVs expand. they will perform a broader range of missions such as air-to-air combat. The focus of this thesis is forming trajectories for the closing phase of an air-to-air combat scenario. A UAV should close with the suspected aircraft in a manner that allows a ground operator to visually identify the suspected aircraft while avoiding visual/electronic detection from the other pilot. This thesis applies and compares three methods for producing trajectories which enable a visual identification. The first approach is formulated as a mixed integer linear programming problem which can be solved in real time. However, there are limitations to the accuracy of a radar detection model formed with only linear equations, which might justify using a nonlinear programming formulation. With this approach the interceptor's radar cross section and range between the suspected aircraft and interceptor can be incorporated into the problem formulation. The main limitation of this method is that the optimization software might not be able to reach online an optimal or even feasible solution. The third applied method is trajectory interpolation. In this approach, trajectories with specified boundary values and dynamics are formed offline; online, the method interpolates between the given trajectories to obtain similar maneuvers with different initial conditions and end- states. With this method, because the number of calculations required to produce a feasible trajectory is known, the amount of time to calculate a trajectory can be estimated.

Download or read book A Novel Collision Avoidance Logic for Unmanned Aerial Vehicles Using Real time Trajectory Planning written by Chi Kin Lai and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: