Aerospace Engineering Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2737
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Item Comparison of Optic Flow in the Visible Light and Infrared Specturms(2008) Chinn, Michael William; Humbert, James S; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Insects use a method of Wide Field Integration (WFI) to navigate efficiently through unknown environments. Using these natural paradigms, various WFI based forms of navigation can be implemented based on electro-mechanical vision devices on robotic vehicles. However, under low light and/or suspended particles in the environment, these methods become less useful. One solution to this problem is to use infrared vision sensors rather than visible light sensors. This would allow insect-like navigation for autonomous vehicles under a variety of lighting conditions, including a total lack of visible light. The results show that, using infrared sensors, it is possible to navigate under a variety of lighting conditions, even where visible light sensors become ineffective.Item Stochastic Properties of Wide Field Integrated Optic Flow Measurements(2009) Owen, Scott; Humbert, James S; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Wide Field Integration (WFI) is a biologically inspired method of spatially decomposing optic flow estimates to extract relevant behavioral cues for navigation. In this thesis, a framework is developed that allows the direct application of a Kalman filter to improve the state information extracted from optic flow measurements. In addition, the noise properties of optic flow measurements are characterized, and an architecture to propagate the uncertainty in optic flow measurements to WFI state estimates is formalized. The closed-loop performance of a ground robot maneuvering in a straight tunnel using WFI outputs is then analyzed using three different algorithms to compute optic flow. The performance of the robot is characterized by its ability to track the tunnel centerline, and the accuracy of the WFI state estimates are compared with the true state estimates using a visual motion capture system. Lastly, the Kalman filter is implemented on a ground robot and the modified closed-loop performance is analyzed.Item Hardware Design of a Wearable System for Gesture-Based Teleoperation of a Robotic Manipulator(2007-06-05) Buchholz, Brooke Teresa; Akin, David; Aerospace Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)To overcome some of the difficulties of robotic teleoperation using hand controllers, a new approach is necessary, namely gesture-based control. A review of sensors currently in use for human joint angle measurement is presented. Based on this review, a method was chosen that uses a variable-length fiber optic sensor. Several different types of optical fibers, along with a variety of test configurations, were initially evaluated, and the most promising of these were selected for further testing. This thesis describes these methods of evaluation and the final system design and testing of a wearable system for gesture-based control of a robotic manipulator, including a discussion of sensor placement to obtain improved results. The final system presented requires improvements and continued research to become usable for robotic control. However, the basic concept and design are shown to provide reliable information regarding relative human joint motion.