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 Die Stollbeule und ihre Behandlung in geschichtlicher Beleuchtung written by Hermann Clemens Rudolf Rechenberger and published by . This book was released on 1914 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Master s Theses Directories written by and published by . This book was released on 2004 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Education, arts and social sciences, natural and technical sciences in the United States and Canada".

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 Selected papers from the 2nd International Symposium on UAVs Reno U S A June 8 10 2009 written by Kimon P. Valavanis and published by Springer Science & Business Media. This book was released on 2011-04-11 with total page 519 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last decade, signi?cant changes have occurred in the ?eld of vehicle motion planning, and for UAVs in particular. UAV motion planning is especially dif?cult due to several complexities not considered by earlier planning strategies: the - creased importance of differential constraints, atmospheric turbulence which makes it impossible to follow a pre-computed plan precisely, uncertainty in the vehicle state, and limited knowledge about the environment due to limited sensor capabilities. These differences have motivated the increased use of feedback and other control engineering techniques for motion planning. The lack of exact algorithms for these problems and dif?culty inherent in characterizing approximation algorithms makes it impractical to determine algorithm time complexity, completeness, and even soundness. This gap has not yet been addressed by statistical characterization of experimental performance of algorithms and benchmarking. Because of this overall lack of knowledge, it is dif?cult to design a guidance system, let alone choose the algorithm. Throughout this paper we keep in mind some of the general characteristics and requirements pertaining to UAVs. A UAV is typically modeled as having velocity and acceleration constraints (and potentially the higher-order differential constraints associated with the equations of motion), and the objective is to guide the vehicle towards a goal through an obstacle ?eld. A UAV guidance problem is typically characterized by a three-dimensional problem space, limited information about the environment, on-board sensors with limited range, speed and acceleration constraints, and uncertainty in vehicle state and sensor data.

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 Real time Trajectory Planning for Ground and Aerial Vehicles in a Dynamic Environment written by Jian Yang and published by . This book was released on 2008 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, a novel and generic solution of trajectory generation is developed and evaluated for ground and aerial vehicles in a dynamic environment. By explicitly considering a kinematic model of the ground vehicles, the family of feasible trajectories and their corresponding steering controls are derived in a closed form and are expressed in terms of one adjustable parameter for the purpose of collision avoidance. A collision-avoidance condition is developed for the dynamically changing environment, which consists of a time criterion and a geometrical criterion. By imposing this condition, one can determine a family of collision-free paths in a closed form. Then, optimization problems with respect to different performance indices are setup to obtain optimal solutions from the feasible trajectories. Among these solutions, one with respect to the near-shortest distance and another with respect to the near-minimal control energy are analytical and simple. These properties make them good choices for real-time trajectory planning. Such optimal paths meet all boundary conditions, are twice differentiable, and can be updated in real time once a change in the environment is detected. Then this novel method is extended to 3D space to find a real-time optimal path for aerial vehicles. After that, to reflect the real applications, obstacles are classified to two types: "hard" obstacles that must be avoided, and "soft" obstacles that can be run over/through. Moreover, without losing generality, avoidance criteria are extended to obstacles with any geometric shapes. This dissertation also points out that the emphases of the future work are to consider other constraints such as the bounded velocity and so on. The proposed method is illustrated by computer simulations.

Download or read book Disaster Robotics written by Satoshi Tadokoro and published by Springer. This book was released on 2019-01-20 with total page 536 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces readers to the latest findings on disaster robotics. It is based on the ImPACT Tough Robotics Challenge, a national project spearheaded by the Japan Cabinet Office that focuses on developing robotics technologies to aid in disaster response, recovery and preparedness. It presents six subprojects that involve robot platforms and several component technologies used in conjunction with robots: cyber rescue canines, which are digitally empowered rescue dogs; serpent-like robots for searching debris; serpent-like robots for plant/infrastructure inspection; UAVs for gathering information on large areas struck by disaster; legged robots for plant/infrastructure inspection in risky places; and construction robots for recovery tasks that require both power and precision. The book offers a valuable source of information for researchers, engineers and practitioners in safety, security and rescue robotics, disaster robotics, and plant and infrastructure maintenance. It will also appeal to a wider demographic, including students and academics, as it highlights application scenarios and the total concept for each robot in various scientific and technical contexts. In addition to a wealth of figures and photos that explain these robots and systems, as well as experimental data, the book includes a comprehensive list of published papers from this project for readers to refer to. Lastly, an external website offers video footage and updated information from the International Rescue System Institute.

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 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 Autonomous Tasks Allocation and Path Generation of UAV s written by Cédric Cocaud and published by . This book was released on 2006 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Unmanned Aerial Vehicles written by Kimon P. Valavanis and published by Springer Science & Business Media. This book was released on 2008-02-26 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt: The past decade has seen tremendous interest in the production and refinement of unmanned aerial vehicles, both fixed-wing, such as airplanes and rotary-wing, such as helicopters and vertical takeoff and landing vehicles. This book provides a diversified survey of research and development on small and miniature unmanned aerial vehicles of both fixed and rotary wing designs. From historical background to proposed new applications, this is the most comprehensive reference yet.

Download or read book Differentially Flat Systems written by Hebertt Sira-Ramírez and published by CRC Press. This book was released on 2018-10-03 with total page 489 pages. Available in PDF, EPUB and Kindle. Book excerpt: Illustrating the power, simplicity, and generality of the concept of flatness, this reference explains how to identify, utilize, and apply flatness in system planning and design. The book includes a large assortment of exercises and models that range from elementary to complex classes of systems. Leading students and professionals through a vast array of designs, simulations, and analytical studies on the traditional uses of flatness, Differentially Flat Systems contains an extensive amount of examples that showcase the value of flatness in system design, demonstrate how flatness can be assessed in the context of perturbed systems and apply static and dynamic feedback controller design techniques.

Download or read book Sense and Avoid in UAS written by Plamen Angelov and published by John Wiley & Sons. This book was released on 2012-04-30 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is increasing interest in the potential of UAV (Unmanned Aerial Vehicle) and MAV (Micro Air Vehicle) technology and their wide ranging applications including defence missions, reconnaissance and surveillance, border patrol, disaster zone assessment and atmospheric research. High investment levels from the military sector globally is driving research and development and increasing the viability of autonomous platforms as replacements for the remotely piloted vehicles more commonly in use. UAV/UAS pose a number of new challenges, with the autonomy and in particular collision avoidance, detect and avoid, or sense and avoid, as the most challenging one, involving both regulatory and technical issues. Sense and Avoid in UAS: Research and Applications covers the problem of detect, sense and avoid in UAS (Unmanned Aircraft Systems) in depth and combines the theoretical and application results by leading academics and researchers from industry and academia. Key features: Presents a holistic view of the sense and avoid problem in the wider application of autonomous systems Includes information on human factors, regulatory issues and navigation, control, aerodynamics and physics aspects of the sense and avoid problem in UAS Provides professional, scientific and reliable content that is easy to understand, and Includes contributions from leading engineers and researchers in the field Sense and Avoid in UAS: Research and Applications is an invaluable source of original and specialised information. It acts as a reference manual for practising engineers and advanced theoretical researchers and also forms a useful resource for younger engineers and postgraduate students. With its credible sources and thorough review process, Sense and Avoid in UAS: Research and Applications provides a reliable source of information in an area that is fast expanding but scarcely covered.

Download or read book Robot Operating System ROS written by Anis Koubaa and published by Springer. This book was released on 2017-05-25 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second volume is a continuation of the successful first volume of this Springer book, and as well as addressing broader topics it puts a particular focus on unmanned aerial vehicles (UAVs) with Robot Operating System (ROS). Consisting of three types of chapters: tutorials, cases studies, and research papers, it provides comprehensive additional material on ROS and the aspects of developing robotics systems, algorithms, frameworks, and applications with ROS. ROS is being increasingly integrated in almost all kinds of robots and is becoming the de-facto standard for developing applications and systems for robotics. Although the research community is actively developing applications with ROS and extending its features, amount of literature references is not representative of the huge amount of work being done. The book includes 19 chapters organized into six parts: Part 1 presents the control of UAVs with ROS, while in Part 2, three chapters deal with control of mobile robots. Part 3 provides recent work toward integrating ROS with Internet, cloud and distributed systems. Part 4 offers five case studies of service robots and field experiments. Part 5 presents signal-processing tools for perception and sensing, and lastly, Part 6 introduces advanced simulation frameworks. The diversity of topics in the book makes it a unique and valuable reference resource for ROS users, researchers, learners and developers.

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 Trajectory Generation and Tracking for Drone Racing written by Jonathan Jamieson and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis trajectory generation for quadrotors, a type of rotorcraft UAV (Unmanned Aerial Vehicle), is considered with two diverent methods. The first applies the Maximum Principle of optimal control to derive closed-form analytical functions that describe the translational states for two different cases of nonholonomic constraints. Parametric optimisation is used to find the trajectories. Reachable sets are found numerically and a simple obstacle avoidance method is demonstrated for both cases. The second motion planning method found trajectories with polynomial basis functions that are parametrised by an abstract function between zero and one. This virtual time domain trajectory satisfied conditions placed on the boundary derivatives and followed a sequenceof desired waypoints. A process for finding a mapping function that converts the virtual domain trajectory into one on the standard time domain is developed to minimise the trajectory time whilst ensuring the motion remained feasible by enforcing bounds on the thrust required from each rotor. An algorithm that uses additional waypoints where necessary to ensure the trajectory does not collide with the gates that define the course is developed. A method for minimising the accumulated angular acceleration of the heading angle whilst remaining within a desired tolerance of the velocity vector angle is also described. Trajectory tracking is considered by modifying an existing quadrotor tracking controller on the Special Euclidean group SE(3) to include a Linear Extended State Observer that estimates and counteracts translational disturbances. The modified controller is shown to reduce the position tracking error in the presence of square wave, sinusoidal and wind disturbances.