Wide-Area Surveillance System using a UAV Helicopter Interceptor and Sensor Placement Planning Techniques

This project proposes and describes the implementation of a wide-area surveillance system comprised of a sensor/interceptor placement planning and an interceptor unmanned aerial vehicle (UAV) helicopter. Given the 2-D layout of an area, the planning system optimally places perimeter cameras based on maximum coverage and minimal cost. Part of this planning system includes the MATLAB implementation of Erdem and Sclaroff’s Radial Sweep algorithm for visibility polygon generation. Additionally, 2-D camera modeling is proposed for both fixed and PTZ cases. Finally, the interceptor is also placed to minimize shortest-path flight time to any point on the perimeter during a detection event. Secondly, a basic flight control system for the UAV helicopter is designed and implemented. The flight control system’s primary goal is to hover the helicopter in place when a human operator holds an automatic-flight switch. This system represents the first step in a complete waypoint-navigation flight control system. The flight control system is based on an inertial measurement unit (IMU) and a proportional-integral-derivative (PID) controller. This system is implemented using a general-purpose personal computer (GPPC) running Windows XP and other commercial off-the-shelf (COTS) hardware. This setup differs from other helicopter control systems which typically use custom embedded solutions or micro-controllers. Experiments demonstrate the sensor placement planning achieving \u3e90% coverage at optimized-cost for several typical areas given multiple camera types and parameters. Furthermore, the helicopter flight control system experiments achieve hovering success over short flight periods. However, the final conclusion is that the COTS IMU is insufficient for high-speed, high-frequency applications such as a helicopter control system

Unmanned Aerial Vehicles for Post Disaster Surveys

In the current built environment, structures require regular observation and maintenance. Many of these structures can be quite challenging to evaluate. The required scaffolding, lifts, or similar access facilities can become quite costly to rent and construct, and can be a long term disturbance to those who use and manage the particular structure. Furthermore, there are situations where examination for the purpose of detailed analysis can be quite hazardous, if not entirely unsafe for humans. In a post-disaster environment traditional methods may not be safe or adequate for gaining access to parts of a structure that require observation or analysis. The use of a remotely controlled unmanned vehicle is a reliable, safe and cost effective substitute for assessing structures before and after seismic, terrorist, or other destructive events

Design, Developement, Analysis and Control of a Bio-Inspired Robotic Samara Rotorcraft

THIS body of work details the development of the first at-scale (>15 cm) robotic samara, or winged seed. The design of prototypes inspired by autorotating plant seed geometries is presented along with a detailed experimental process that elucidates similarities between mechanical and robotic samara flight dynamics. The iterative development process and the implementation of working prototypes are discussed for robotic samara Micro-Air-Vehicles (MAV) that range in size from 7.5 cm to 27 cm. Vehicle design issues are explored as they relate to autorotation efficiency, stability, flight dynamics and control of single winged rotorcraft. In recent years a new paradigm of highly maneuverable aircraft has emerged that are ideally suited for operation in a confined environment. Different from conven- tional aircraft, viscous forces play a large role in the physics of flight at this scale. This results in relatively poor aerodynamic performance of conventional airfoil and rotorcraft configurations. This deficiency has led to the consideration of naturally occurring geometries and configurations, the simplest of which is the samara. To study the influence of geometric variation on autorotation efficiency, a high speed camera system was used to track the flight path and orientation of the mechan- ical samaras. The wing geometry is planar symmetric and resembles a scaled version of Acer diabolicum Blume. The airfoil resembles a scaled version of the maple seed with a blunt leading edge followed by a thin section without camber. Four mechan- ical samara geometries with equal wing loading were designed and fabricated using a high precision rapid prototyping machine that ensured similarity between models. It was found that in order to reduce the descent velocity of an autorotating samara the area centroid or maximum chords should be as far from the center of rotation as possible. Flight data revealed large oscillations in feathering and coning angles, and the resultant flight path was found to be dependent on the mean feathering angle. The different flight modalities provided the basis for the design of a control sys- tem for a powered robotic samara that does not require high frequency sensing and actuation typical of micro-scaled rotorcraft. A prototype mechanical samara with a variable wing pitch (feathering) angle was constructed and it was found that active control of the feathering angle allowed the variation of the radius of the helix carved by the samara upon descent. This knowledge was used to design a hovering robotic samara capable of lateral motion through a series of different size circles specified by precise actuation of the feathering angle. To mathematically characterize the flight dynamics of the aircraft, System identi- fication techniques were used. Using flight data, a linear model describing the heave dynamics of two robotic samara vehicles was verified. A visual positioning system was used to collect flight data while the vehicles were piloted in an indoor laboratory. Closed-loop implementation of the derived PID controller was demonstrated using the visual tracking system for position and velocity feedback. An approach to directional control that does not require the once-per-revolution actuation or high-frequency measurement of vehicle orientation has been demon- strated for the first time. Lateral flight is attained through the vehicles differing responses to impulsive and step inputs that are leveraged to create a control strategy that provides full controllability. Flight testing revealed several linear relationships, including turn rate, turn radius and forward speed. The steady turn discussed here has been observed in scaled versions of the robotic samara, therefore the open-loop control demonstrated and analyzed is considered to be appropriate for similar vehicles of reduced size with limited sensing and actuation capabilities

INSPIRE Newsletter Spring 2018

https://scholarsmine.mst.edu/inspire-newsletters/1002/thumbnail.jp

Continuous Autonomous UAV Inspection for FPSO vessels

This Master's thesis represents the preliminary design study and proposes the unmanned aerial vehicle (UAV) -based inspection framework, comprising several multirotors with automatic charging and deployment for 24/7 integrity inspection tasks. This project has three main topics. First one describes the operational environment and existing regulations that cover use of UAVs. It forms the basis for proposal of the relevant use-case scenarios. Third part comprises two chapters, where design of concept and framework is being based on the previous factors. It shows that before implementation of fully autonomous inspection system, there is a need to cover both regulatory and technical gaps. It can be explained by the fact that there does not exist any autonomous inspection system today. Thus, this project can be seen as a base for future development of the UAV-based inspection system, as it focuses on creation of a general framework

The Design Fabrication and Flight Testing of an Academic Research Platform for High Resolution Terrain Imaging

This thesis addresses the design, construction, and flight testing of an Unmanned Aircraft System (UAS) created to serve as a testbed for Intelligence, Surveillance, and Reconnaissance (ISR) research topics that require the rapid acquisition and processing of high resolution aerial imagery and are to be performed by academic research institutions. An analysis of the requirements of various ISR research applications and the practical limitations of academic research yields a consolidated set of requirements by which the UAS is designed. An iterative design process is used to transition from these requirements to cycles of component selection, systems integration, flight tests, diagnostics, and subsystem redesign. The resulting UAS is designed as an academic research platform to support a variety of ISR research applications ranging from human machine interaction with UAS technology to orthorectified mosaic imaging. The lessons learned are provided to enable future researchers to create similar systems

Navigation of Unmanned Aerial Vehicles in GPS-denied Environments

Ph.DDOCTOR OF PHILOSOPH