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Articles 1 - 11 of 11
Full-Text Articles in Navigation, Guidance, Control and Dynamics
Design And Implementation Of An Embedded Control System For The Cal Poly Spacecraft Attitude Dynamics Simulator, Neil Mahesh Bedagkar
Design And Implementation Of An Embedded Control System For The Cal Poly Spacecraft Attitude Dynamics Simulator, Neil Mahesh Bedagkar
Master's Theses
This thesis presents the development of a cascaded reaction wheel control system for Cal Poly's Spacecraft Attitude Dynamics Simulator. This work considers system architecture, empirical modeling, high-fidelity simulation, embedded firmware, hardware integration, and experimental characterization. In discrete-time simulation, it is shown that nonlinear direct model reference adaptive control (NDMRAC) enables a nonlinear, partially known plant with realistic actuator dynamics to track the response of a canonical second-order transfer function, with settling time within 4.67% and percent overshoot within order of magnitude of the second-order response. In hardware, the feasibility of a cascaded reaction wheel control architecture is experimentally demonstrated, achieving …
Satellite Reorientation Using Reinforcement Learning Under Unknown Attitude Failure, Matthew Willoughby
Satellite Reorientation Using Reinforcement Learning Under Unknown Attitude Failure, Matthew Willoughby
Doctoral Dissertations and Master's Theses
This study presents a reinforcement learning (RL) approach for reestablishing communication with deep-space satellites under unknown attitude determination and control system (ADCS) failures. When traditional fault-tolerant control methods cannot restore signal, the proposed RL controller acts as a last-resort measure by autonomously reorienting the satellite’s antenna toward Earth while charging the battery via solar panels. A generic reward function, designed for the RL-based method, enables the controller to adapt to diverse failure scenarios, including severe actuator noise, misalignment, and complete actuator failure. Simulations are conducted in the Basilisk environment and trained with the tonic framework and demonstrate ranging capabilities of …
Mass-Adaptive Admittance Control For Robotic Manipulators, Hossein Gholampour, Jonathon E. Slightam, Logan E. Beaver
Mass-Adaptive Admittance Control For Robotic Manipulators, Hossein Gholampour, Jonathon E. Slightam, Logan E. Beaver
Mechanical & Aerospace Engineering Faculty Publications
Handling objects with unknown or changing masses is a common challenge in robotics, often leading to errors or instability if the control system cannot adapt in realtime. In this paper, we present a novel approach that enables a six-degrees-of-freedom robotic manipulator to reliably follow waypoints while automatically estimating and compensating for unknown payload weight. Our method integrates an admittance control framework with a mass estimator, allowing the robot to dynamically update an excitation force to compensate for the payload mass. This strategy mitigates end-effector sagging and preserves stability when handling objects of unknown weights. We experimentally validated our approach in …
Adaptive Control Of Vscmgs For Satellite Attitude Tracking, Kyle Vernyi
Adaptive Control Of Vscmgs For Satellite Attitude Tracking, Kyle Vernyi
Doctoral Dissertations and Master's Theses
The democratization of space has brought about many new opportunities and challenges for industry, academia, and governments. Smaller and more affordable platforms are now regularly being launched. These platforms have higher uncertainty due to cost, engineering constraints, unmodeled dynamics, coupled effects, and the challenging space environment. In addition, both mission requirements and complexity are simultaneously being increased. In order to achieve these requirements, new satellite control algorithms are required. Adaptive control offers a strong solution to the uncertainty problem. This thesis develops several adaptive control algorithms for satellites equipped with momentum management devices. Momentum management devices such as reaction wheels …
Nonlinear Dynamics Analysis And Control Of Space Vehicles With Flexible Structures, Marco Fagetti
Nonlinear Dynamics Analysis And Control Of Space Vehicles With Flexible Structures, Marco Fagetti
Doctoral Dissertations and Master's Theses
Space vehicles that implement hardware such as antennas, solar panels, and other extended appendages necessary for their respective missions must consider the nonlinear rotational and vibrational dynamics of these flexible structures. Formulation and analysis of these flexible structures must account for the rigid-flexible coupling present in the system dynamics for stability analysis and control design. The system model is represented by a flexible appendage attached to a central rigid body, where the flexible appendage is modeled as a cantilevered Euler-Bernoulli beam. Discretization techniques, such as the assumed modes method and the finite element method, are used to model the coupled …
Adaptive And Neural Network-Based Aircraft Tracking Control With Synthetic Jet Actuators, Joshua Teramae
Adaptive And Neural Network-Based Aircraft Tracking Control With Synthetic Jet Actuators, Joshua Teramae
Doctoral Dissertations and Master's Theses
Wing-embedded synthetic jet actuators (SJA) can be used to achieve maneuvering control in aircraft by delivering controllable airflow perturbations near the wing surface. Trajectory tracking control design for aircraft equipped with SJA is particularly challenging, since the controlling actuator itself has an uncertain dynamic model. These challenges necessitate advanced nonlinear control design methods to achieve desirable performance for SJA-based aircraft (e.g., micro air vehicles (MAVs)). In this research, adaptive and neural-network based control methods are investigated, which are specifically designed to compensate for the SJA dynamic model uncertainty and unpredictable operating conditions characters tic of real-world MAV applications. The control …
Uas Model Identification And Simulation To Support In-Flight Testing Of Discrete Adaptive Fault-Tolerant Control Laws, Mansi Subhash Bakori
Uas Model Identification And Simulation To Support In-Flight Testing Of Discrete Adaptive Fault-Tolerant Control Laws, Mansi Subhash Bakori
Doctoral Dissertations and Master's Theses
In mission-critical applications of unmanned and autonomous aerial systems(UAS), it is of significant importance to develop robust strategies for fault-tolerant systems that can countermeasure system degradation and consequently support the integration into the National Airspace (NAS). This thesis research illustrates the results of systems identification that is performed using DATCOM followed by the flight test data. This data is acquired from conducting an intensive flight testings program of a fixed-wing UAS to determine the state-space model of the aircraft. A discrete state-space system is reconstructed from these models to derive Auto-Regressive Moving-Average (ARMA) models used to design a Discrete Direct …
Adaptive Commanding Of Control Moment Gyroscopes With Backlash, Justin G. Bourke
Adaptive Commanding Of Control Moment Gyroscopes With Backlash, Justin G. Bourke
Doctoral Dissertations and Master's Theses
The existence of backlash in mechanical systems provides significant challenges when attempting to control these systems to a high degree of precision. The imperfect meshing of gear or belt teeth deteriorates the performance of position controllers and tracking of small commands, producing unacceptable steady-state offsets, increased rise and settling times. Agile spacecraft often use control moment gyroscopes (CMGs) equipped with gear trains to efficiently provide torque for the fine attitude adjustments used in docking and precision stabilization maneuvers. A theoretical examination and a practical model is developed to study the effectiveness of both proportional-integral (PI) and model referencing adaptive controllers …
Direct Adaptive Control For A Trajectory Tracking Uav, Nirmit Prabhakar
Direct Adaptive Control For A Trajectory Tracking Uav, Nirmit Prabhakar
Doctoral Dissertations and Master's Theses
This research focuses on the theoretical development and analysis of a direct adaptive control algorithm to enable a fixed-wing UAV to track reference trajectories while in the presence of persistent external disturbances. A typical application of this work is autonomous flight through urban environments, where reference trajectories would be provided by a path planning algorithm and the vehicle would be subjected to significant wind gust disturbances. Full 6-DOF nonlinear and linear UAV simulation models are developed and used to study the performance of the direct adaptive control system for various scenarios. A stability proof is developed to prove convergence of …
System And Method For Robust Nonlinear Regulation Control Of Unmanned Aerial Vehicles Synthetic Jet Actuators, Vladimir Golubev, William Mackunis
System And Method For Robust Nonlinear Regulation Control Of Unmanned Aerial Vehicles Synthetic Jet Actuators, Vladimir Golubev, William Mackunis
Publications
An unmanned aerial vehicle (UAV) is provided with a plurality of synthetic jet actuators and a nonlinear robust controller. The controller compensates for uncertainty in a mathematic model that describes the function of the synthetic jet actuators. Compensation is provided by the use of constant feedforward best guess estimates that eliminate the need for more highly computationally burdensome approaches such as the use of time-varying adaptive parameter estimation algorithms.
Robust And Adaptive Nonlinear Control Of Limit Cycle Oscillations In Uavs Using Synthetic Jet Actuators, Natalie Ramos Pedroza
Robust And Adaptive Nonlinear Control Of Limit Cycle Oscillations In Uavs Using Synthetic Jet Actuators, Natalie Ramos Pedroza
Doctoral Dissertations and Master's Theses
Limit cycle oscillations (LCO), also known as utter, cause significant challenges in fight control of unmanned aerial vehicles (UAVs), and could potentially lead to structural damage and catastrophic failures. LCO can be described as vibrational motions in the pitching and plunging displacements of an aircraft wing. Even in low Reynolds number (low-Re) fight regimes, LCO can exceed the limiting boundary for safe UAV fight. Further, as practical considerations motivate the design of smaller, lighter weight UAVs, there is a growing need for UAV systems that do not require heavy mechanical actuators (e.g., ailerons). To address this, the use of synthetic …