Aerospace Engineering Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2737
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Item Multi-Domain Human-Robot Interfaces(2024) Abdi, Sydrak Solomon; Paley, Derek; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)As autonomous robots become more capable and integrated into daily society, it becomes crucial to consider how a user will interact with them, how a robot will perceive a user, and how a robot will comprehend a user’s intentions. This challenge increases in difficulty when the user is required to interact with and control multiple robots simultaneously. Human intervention is often required during autonomous operations, particularly in scenarios that involve complex decision-making or where safety concerns arise. Thus, the methods by which users interact with multi-agent systems is an important area of research. These interactions should be intuitive, efficient, and effective all while preserving the operator's safety. We present a novel human swarm interface (HSI) that utilizes gesture control and haptic feedback to interact with and control a swarm of quadrotors in a confined space. This human swarm interface prioritizes operator safety while reducing cognitive load during control of an aerial swarm. Human-robot interfaces (HRIs) are mechanisms designed to facilitate communication between humans and robots, enhancing the user's ability to command and collaborate with robots in an intuitive and user-friendly manner. One challenge is providing mobile robotic systems with the capability to localize and interact with a user in their environment. Localization involves estimating the pose (position and orientation) of the user relative to the robot, which is essential for tasks that require close interactions or navigation in shared spaces. We present a novel method for obtaining user pose as well as other anthropometric measurements useful for human-robot interactions. Another challenge is extending these HRI and HSI paradigms to the outdoors. Unlike controlled laboratory conditions, outdoor environments involve a variety of variables such as fluctuating weather conditions as well as a mix of static and dynamic obstacles. In this dissertation, we design a portable human swarm interface that allows an operator to interact with and control a multi-agent system outdoors. The portable HSI takes the form of smart binoculars. The user uses the smart binoculars to select an outdoor location and assign a task for the multi-agent system to complete given the targeted area. This system allows for new methods of multi-agent operation, that will leverage a user's on-the-ground knowledge while utilizing autonomous vehicles for line-of-sight operations, without compromising their situational awareness.Item Quaternion-Based Control for Aggressive Trajectory Tracking with a Micro-Quadrotor UAV(2014) Kehlenbeck, Andrew Gale; Humbert, James S; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)With potential missions for quadrotor micro-air vehicles (MAVs) calling for smaller, more agile vehicles, it is important to implement attitude controllers that allow the vehicle to reach any desired attitude without encountering computational singularities, as is the case when using an Euler angle representation. A computationally efficient quaternion-based state estimator is presented that enables the Army Research Laboratory's (ARL) 100-gram micro-quadrotor to determine its attitude during agile maneuvers using only an on-board gyroscope and accelerometer and a low-power processor. Inner and outer loop attitude and position controllers are also discussed that use the quaternion attitude representation to control the vehicle along aggressive trajectories with the assistance of an outside motion capture system. A trajectory generation algorithm is then described that leverages the quadrotor's inherent dynamics to allow it to reach extreme attitudes for applications such as perching on walls or ceilings and flying through small openings.Item An Observer for Estimating Translational Velocity from Optic Flow and Radar(2011) Gerardi, Steven Anthony; Humbert, James S; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This thesis presents the development of a discrete time observer for estimating state information from optic flow and radar measurements. It is shown that estimates of translational and rotational speed can be extracted using a least squares inversion for wide fields of view or, with the addition of a Kalman Filter, for small fields of view. The approach is demonstrated in a simulated three dimensional urban environment on an autonomous quadrotor micro-air-vehicle (MAV). A state feedback control scheme is designed, whereby the gains are found via static H∞, and implemented to allow trajectory following. The proposed state estimation scheme and feedback method are shown to be sufficient for enabling autonomous navigation of an MAV. The resulting methodology has the advantages of computational speed and simplicity, both of which are imperative for implementation on MAVs due to stringent size, weight, and power requirements.