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Articles 1 - 9 of 9
Full-Text Articles in Mechanical Engineering
Formation Control With Collision Avoidance For Fixed-Wing Unmanned Air Vehicles With Speed Constraints, Christopher Heintz
Formation Control With Collision Avoidance For Fixed-Wing Unmanned Air Vehicles With Speed Constraints, Christopher Heintz
Theses and Dissertations--Mechanical Engineering
Advances in the miniaturization of powerful electronic components and motors, the democratization of global navigation satellite systems (GNSS), and improvements in the performance, safety, and cost in lithium batteries has led to the proliferation of small and relatively inexpensive unmanned aerial vehicles (UAVs). Many of these UAVs are of the multi-rotor design, however, fixed-wing designs are often more efficient than rotary-wing aircraft, leading to a reduction in the power required for a UAV of a given mass to stay airborne. Autonomous cooperation between multiple UAVs would enable them to complete objectives that would be difficult or impossible for a single …
Model Predictive Power Management Of A Hybrid Electric Propulsion System For Aircraft, Tyler J. Wall
Model Predictive Power Management Of A Hybrid Electric Propulsion System For Aircraft, Tyler J. Wall
Masters Theses
This work presents the switched optimal power flow control for an aircraft with a hybrid electric propulsion system. The propulsion system is a switched system that operates in either of two modes: (i) battery discharging and electric motor propelling and (ii) battery charging and electric motor generating. The aircraft model and components that form the hybrid propulsion system are modeled as either an algebraic power source/sink or as a dynamic model with appropriate power and state interconnections. With the system model defined, a model predictive control power management strategy is set fourth which minimizes a performance index that includes altitude …
Cyber-Physical System Characterization And Co-Regulation Of A Quadrotor Uas, Seth E. Doebbeling
Cyber-Physical System Characterization And Co-Regulation Of A Quadrotor Uas, Seth E. Doebbeling
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
An Unmanned Aircraft System (UAS) is a Cyber-Physical System (CPS) in which a host of real-time computational tasks contending for shared resources must be cooperatively managed to obtain mission objectives. Traditionally, control of the UAS is designed assuming a fixed, high sampling rate in order to maintain reliable performance and margins of stability. But emerging methods challenge this design by dynamically allocating resources to computational tasks, thereby affecting control and mission performance. To apply these emerging strategies, a characterization and understanding of the effects of timing on control and trajectory following performance is required. Going beyond traditional control evaluation techniques, …
Control Of A Spacecraft Using Mixed Momentum Exchange Devices, Blake J. Currie
Control Of A Spacecraft Using Mixed Momentum Exchange Devices, Blake J. Currie
Master's Theses
Hardware configurations, a control law, and a steering law are developed for a mixed hardware spacecraft that uses both control moment gyros and reaction wheels. Replacing one or more gyros in a spacecraft with a reaction wheel has potential for cost savings while still achieving much greater performance than using reaction wheels alone. Several simulated tests are run to compare the performance to a traditional all reaction wheel or all control moment gyro spacecraft, including analysis of failure modes and singular configurations. The mixed system performed similarly to all gyro systems, responding within 6% of the gyro system’s time for …
Feedback Speed Control Of A Small Two-Stroke Internal Combustion Engine That Propels An Unmanned Aerial Vehicle, Paul D. Fjare
Feedback Speed Control Of A Small Two-Stroke Internal Combustion Engine That Propels An Unmanned Aerial Vehicle, Paul D. Fjare
UNLV Theses, Dissertations, Professional Papers, and Capstones
Unmanned aerial vehicles (UAV) require intelligent control of their power source. Small UAV are typically powered by electric motors or small two-stroke internal combustion (IC) engines. Small IC engines allow for longer flight times but are more difficult to control and cause significant ground noise. A hybrid operation that uses the engine at high altitudes and the electric motors at low altitudes is desired. This would allow for extended flight with acceptable ground noise levels. Since the engine can not be restarted in the air it must be able to remain at idle for an extended time without stalling. A …
Adaptive Nonlinear Control For Autonomous Ground Vehicles, William Spencer Black
Adaptive Nonlinear Control For Autonomous Ground Vehicles, William Spencer Black
Open Access Theses
We present the background and motivation for ground vehicle autonomy, and focus on uses for space-exploration. Using a simple design example of an autonomous ground vehicle we derive the equations of motion. After providing the mathematical background for nonlinear systems and control we present two common methods for exactly linearizing nonlinear systems, feedback linearization and backstepping. We use these in combination with three adaptive control methods: model reference adaptive control, adaptive sliding mode control, and extremum-seeking model reference adaptive control. We show the performances of each combination through several simulation results. We then consider disturbances in the system, and design …
Instrumentation, Control And Torch Ignition Systems Development For Lox/Methane Propulsion Research, Jesus Betancourt-Roque
Instrumentation, Control And Torch Ignition Systems Development For Lox/Methane Propulsion Research, Jesus Betancourt-Roque
Open Access Theses & Dissertations
A liquid propulsion research facility has been developed at the Center for Space Exploration Technology Research at The University of Texas at El Paso. This facility has capabilities for producing up to 25 liters of Liquid Methane, feeding LOX/Methane propellants to 100 N class thrusters and conducting automated steady state and pulsing combustion experiments. This work describes the design, development and testing process of the Data Acquisition and Remote Control System developed to integrate an Altitude Simulation System, a Cryogenic Delivery System, and multiple rocket combustors and thrusters. A Torch Ignition System development is detailed as well as the evaluation …
Optimization Of Torquer Coil Design For Use With The Small Satellite Attitude Control Simulator, David Deloyd Anderson
Optimization Of Torquer Coil Design For Use With The Small Satellite Attitude Control Simulator, David Deloyd Anderson
Undergraduate Honors Capstone Projects
This paper presents a procedure used to optimize the performance of a ferromagnetic core magnetic torquer coil design for use on the Space Dynamics Laboratory (Logan, UT) Small Satellite Attitude Control Simulator. The items of optimization include the primary goal of maximizing the coil 's magnetic moment while reducing power consumption and system mass within given power, mass, and dimensional constraints. The optimization process makes use of several simple equations to determine a few starting points for design, after which an iterative approach based on experimentation is used to produce the final design. It is found that optimal magnetic moment …
Integrated Control Of Thermally Distorted Large Space Antennas, Robert H. Tolson
Integrated Control Of Thermally Distorted Large Space Antennas, Robert H. Tolson
Mechanical & Aerospace Engineering Theses & Dissertations
Studies on controlling the thermal distortion of large space antennae have generally investigated a single orbital position and have optimized actuator locations based on minimizing the RMS surface deviation from the original parabolic shape. One study showed the benefits of directly using far zone electric field characteristics as the performance measure; but, this approach resulted in a nonlinear programming problem. The objective of the current study is to develop an approach to designing a control system that (1) recognizes the time dependence of the distortion and (2) controls variables that are directly related to far field performance in a quadratic …