Indoor GPS-denied Context Based SLAM Aided Guidance for Autonomous Unmanned Aerial Systems

Presented at AIAA Guidance, Control, and Navigation (GNC) conference, 2013.DOI: dx.doi.org/10.2514/6.2013-4989Autonomous exploration and mapping of environments is an important problem in robotics. Efficient exploration of structured environments requires that the robot utilize region-specific exploration strategies and coordinate with search other agents. This paper details the exploration and guidance system of a multi-quadrotor unmanned aerial system (UAS) capable of exploring cluttered indoor areas without relying on any external aides. Specifically, a graph-based frontier search algorithm which is aided by an onboard Simultaneous Localization and Mapping (SLAM) system is developed and flight tested. A technique is developed in for segmenting an indoor office-like environment into regions and to utilize the SLAM map to conduct specific activities in these regions. A goal-directed exploration strategy is created building on existing hybrid deliberative-reactive approaches to exploration. An obstacle avoidance and guidance system is implemented to ensure that the vehicle explores maximum indoor area while avoiding obstacles. The environment is explored and regions are segmented by detecting rooms and hallways which expedites the search. The multi-vehicle system is Georgia Tech Aerial Robotic Team's entry for the annual International Aerial Robotics Competition (IARC)

Situational and Terrain Awareness and Warning System Implementation on Android Smartphone for Manned Aviation Applications

General aviation (GA) aircraft are for the most part not equipped with situational awareness or alerting systems, namely in terms of traffic or terrain collision. This is largely due to lack of regulatory requirements, but also because such systems tend to be costly. By over an order of magnitude, these types of aircraft are the most common in the world's airspace. Their prevalence, combined with their more terrain-proximal flight profiles, make GA aircraft most susceptible to controlled flight into terrain (CFIT) incidents. We introduce an economical situational awareness and alerting system in an attempt to mitigate CFIT accidents in otherwise uninstrumented GA aircraft. We do so using a common smartphone to run an application which interfaces with NASA's Shuttle Radar Topography Mission (SRTM) digital terrain elevation database (DTED)

Georgia Tech Team Entry for the 2011 AUVSI International Aerial Robotics Competition

Presented at the Third International Aerial Robotics Symposium (IASR), 2011.his paper describes the details of a Quadrotor Unmanned Aerial Vehicle capable of exploring cluttered indoor areas without relying on any external navigational aids. An elaborate Simultaneous Localization and Mapping (SLAM) algorithm is used to fuse information from a laser range sensor, an inertial measurement unit, and an altitude sonar to provide relative position, velocity, and attitude information. A wall-following guidance rule is implemented to ensure that the vehicle explores maximum indoor area in a reasonable amount of time. A model reference adaptive control architecture is used to ensure stability and mitigation of uncertainties. The vehicle is intended to be Georgia Tech Aerial Robotic Team's entry for the 2011 International Aerial Robotics Competition (IARC) Symposium on Indoor Flight Issues

Georgia Tech Team Entry for the 2013 AUVSI International Aerial Robotics Competition

Presented at the Fifth International Aerial Robotics Competition (IARC) Symposium on Indoor Flight Issues, Grand Forks, ND, August, 201

Georgia Tech Team Entry for the 2012 AUVSI International Aerial Robotics Competition

Presented at the Third International Aerial Robotics Symposium (IASR), 2012.This paper describes the details of a Quadrotor Unmanned Aerial Vehicle capable of exploring cluttered indoor areas without relying on any external navigational aids. A Simultaneous Localization and Mapping (SLAM) algorithm is used to fuse information from a laser range sensor, an inertial measurement unit, and an altitude sonar to provide relative position, velocity, and attitude information. A wall avoidance and guidance system is implemented to ensure that the vehicle explores maximum indoor area. A model reference adaptive control architecture is used to ensure stability and mitigation of uncertainties. Finally, an object detection system is implemented to identify target objects for retrieval

Electric multirotor design and optimization

This work satisfies the need for more thorough method of propulsion component selection for electric VTOL (eVTOL) propulsion system design by bridging traditional aircraft sizing and electric multirotor design. Presented here is a framework for both analysis of an existing propulsion system, and also optimization of a propulsion system given a set of mission requirements for generic multirotor vehicles. The system of both the analyzer and optimizer is termed multirotor sizing tool (MST). The analyzer is capable of taking in and/or estimating a multitude of propulsion system parameters to predict the performance profile of the system including range, endurance, speed, power, sensitivities. The optimizer designs a propulsion system to satisfy goals such as desired endurance, range, maneuverability, and so forth. It designs the lightest possible vehicle within in a range of design variables set by the user. The modeling of electrical propulsion system components is described. MST is then used to design several vehicles which are built and flown, and predicted vs. measured data are presented. In addition to describing the MST, the study addresses the optimization of orientation of selected rotors in order to achieve rates in multiple axes. A study of configurations and effects on rate authority is also presented, including combinations of co-axial and pusher/tractor configurations, standard, non-standard coplanar and non-coplanar rotor layouts and different frames. Thrust stand, wind tunnel, and flight test results are included. Two novel configuration designs are presented, both an upgrade of existing configurations.Ph.D

The Semi-Coaxial Multirotor

Copyright © 2018 by the American Helicopter Society International, Inc.The ”semi-coaxial” multirotor configuration is presented including its advantages over the conventional coaxial rotor configuration. The semi-coaxial configuration retains the benefits of the coaxial configuration, and additionally alleviates the loss of efficiency encountered when rotors are stacked coaxially. In addition to being more power-efficient than the standard coaxial configuration, the described configuration allows for nearly- or fully-actuated control of a multirotor when used in configurations such as the three-armed Y6 hexarotor. Using this configuration, a new Direct Force Control (DFC) multirotor is presented: the Y6sC, a specific example of the semi-coaxial multirotor. The configuration orients six rotors in a way which allows the vehicle to hover in non-zero attitudes and translate without rotating with higher efficiency than the corresponding coaxial design

Benchmarking of UAV Guidance Systems in Nap of the Earth (NOE) Flight

Presented at the 70th AHS Annual Forum, Montreal, Quebec, Canada, May 20–22, 2014.This paper describes the development of a proposed framework of metrics for the evaluation of the performance of aircraft guidance systems. The methodologies and metrics developed remain generally agnostic to whether or not the aircraft is manned. Although more complicated missions such as autonomous exploration/search, ferry, surveillance, multi-agent collaboration, and manned flight may be addressed at a later time, A-B flight scenarios are chosen to study the proposed metrics. The proposed metrics will form building blocks for the more complicated missions. Metrics development has thus far generally focused on NOE flight, and in particular on the observability of the vehicle throughout its mission. That is, a formulation of probability of detection by potential and generally unknown threats in the mission area will be the main metric. Secondary metrics provide insight into the vehicle's trajectory quality in terms of safety and comfort, experienced by both humans and machines are described as well. Scalability of the benchmarking system is also important and benchmarking should be general enough to allow guidance algorithms to be graded independently of the vehicle platform, for instance. Non-dimensionalization metrics will address this concern

Situational and Terrain Awareness and Warning System Implementation on Android Smartphone for Manned Aviation Applications

Presented at AIAA SciTech meeting, 2014.DOI: dx.doi.org/10.2514/6.2014-1046General aviation (GA) aircraft are for the most part not equipped with situational awareness or alerting systems, namely in terms of traffic or terrain collision. This is largely due to lack of regulatory requirements, but also because such systems tend to be costly. By over an order of magnitude, these types of aircraft are the most common in the world's airspace. Their prevalence, combined with their more terrain-proximal flight profiles, make GA aircraft most susceptible to controlled flight into terrain (CFIT) incidents. We introduce an economical situational awareness and alerting system in an attempt to mitigate CFIT accidents in otherwise uninstrumented GA aircraft. We do so using a common smartphone to run an application which interfaces with NASA's Shuttle Radar Topography Mission (SRTM) digital terrain elevation database (DTED)

Vision-Based Optimal Landing On a Moving Platform

© 2016 American Helicopter Society International, Inc. All rights reserved.This paper describes a vision-based control architecture designed to enable autonomous landing on a moving platform. The landing trajectory is generated by using the receding-horizon differential dynamic programming (DDP), an optimal control method. The trajectory generation is aided by the output of a vision-based target tracking system. The vision system uses multiple extended Kalman filters which allows us to estimate the position and heading of the moving target via the observed locations. The combination of vision-based target tracking system and the receding-horizon DDP gives an unmanned aerial vehicle the capability to adaptively generate a landing trajectory against tracking errors and disturbances. Additionally, by adding the exterior penalty function to the cost of the DDP we can easily constrain the trajectory from collisions and physically infeasible solutions. We provide key mathematics needed for the implementation and share the results of the image-in-the-loop simulation and flight tests to validate the suggested methodology