Ehsan Taheri
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View article: Classification and Feasibility Assessment of Infinitely Many Iso-Impulse Three-Dimensional Trajectories
Classification and Feasibility Assessment of Infinitely Many Iso-Impulse Three-Dimensional Trajectories Open
In two-body dynamics, it is proven that for a sufficiently long flight time, generating infinitely many iso-impulse solutions is possible by solving a number of $$\Delta v$$ -allocation problems analytically. A distinct feature of these is…
View article: Eigendecomposition Parameterization of Penalty Matrices for Enhanced Control Design: Aerospace Applications
Eigendecomposition Parameterization of Penalty Matrices for Enhanced Control Design: Aerospace Applications Open
Modern control algorithms require tuning of square weight/penalty matrices appearing in quadratic functions/costs to improve performance and/or stability output. Due to simplicity in gain-tuning and enforcing positive-definiteness, diagona…
View article: Constrained Fuel and Time Optimal 6DOF Powered Descent Guidance Using Indirect Optimization
Constrained Fuel and Time Optimal 6DOF Powered Descent Guidance Using Indirect Optimization Open
Powered descent guidance (PDG) problems subject to six-degrees-of-freedom (6DOF) dynamics allow for enforcement of practical attitude constraints. However, numerical solutions to 6DOF PDG problems are challenging due to fast rotational dyn…
View article: Utilizing the Finite Fourier Series to Generate Quadrotor Trajectories Through Multiple Waypoints
Utilizing the Finite Fourier Series to Generate Quadrotor Trajectories Through Multiple Waypoints Open
Motion planning is critical for ensuring precise and efficient operations of unmanned aerial vehicles (UAVs). While polynomial parameterization has been the prevailing approach, its limitations in handling complex trajectory requirements h…
View article: Classification and Feasibility Assessment of Infinitely Many Iso-Impulse Three-Dimensional Trajectories
Classification and Feasibility Assessment of Infinitely Many Iso-Impulse Three-Dimensional Trajectories Open
In two-body dynamics, it is proven that for a sufficiently long flight time, generating infinitely many iso-impulse solutions is possible by solving a number of $Δv$-allocation problems analytically. A distinct feature of these solutions i…
View article: Jacobian Coloring for Multi-Impulse Cislunar Trajectory Optimization
Jacobian Coloring for Multi-Impulse Cislunar Trajectory Optimization Open
View article: A Control System Design and Implementation for Autonomous Quadrotors with Real-Time Re-Planning Capability
A Control System Design and Implementation for Autonomous Quadrotors with Real-Time Re-Planning Capability Open
Real-time (re-)planning is crucial for autonomous quadrotors to navigate in uncertain environments where obstacles may be detected and trajectory plans must be adjusted on-the-fly to avoid collision. In this paper, we present a control sys…
View article: End-to-End Lyapunov-Based Eclipse-Feasible Low-Thrust Transfer Trajectories to NRHO
End-to-End Lyapunov-Based Eclipse-Feasible Low-Thrust Transfer Trajectories to NRHO Open
Generating low-thrust transfer trajectories between Earth and the Near Rectilinear Halo Orbit (NRHO), that is selected for NASA's Gateway, can be challenging due to the low control authority available from the propulsion system and the imp…
View article: Time-Triggered Reduced Desensitization Formulation For Solving Optimal Control Problems
Time-Triggered Reduced Desensitization Formulation For Solving Optimal Control Problems Open
Fuel-optimal trajectories are inherently sensitive to variations in model parameters, such as propulsion system thrust magnitude. This inherent sensitivity can lead to dispersions in cost-functional values, when model parameters have uncer…
View article: Comparison of control regularization techniques for minimum-fuel low-thrust trajectory design using indirect methods
Comparison of control regularization techniques for minimum-fuel low-thrust trajectory design using indirect methods Open
Minimum-fuel low-thrust trajectories typically consist of a finite, yet unknown number of switches in the thrust magnitude profile. This optimality-driven characteristic of minimum-fuel trajectories poses a challenge to the numerical metho…
View article: Co-optimization of spacecraft and low-thrust trajectory with direct methods
Co-optimization of spacecraft and low-thrust trajectory with direct methods Open
Solar-powered electric propulsion systems can operate in multiple modes and their operation is coupled to the power generated by solar arrays. However, the power produced by the solar arrays is a function of the solar array size and helioc…
View article: Expanding the Class of Quadratic Control-Lyapunov Functions for Low-Thrust Trajectory Optimization
Expanding the Class of Quadratic Control-Lyapunov Functions for Low-Thrust Trajectory Optimization Open
Control laws derived from Control-Lyapunov Functions (CLFs) offer an efficient way for generating near-optimal many-revolution low-thrust trajectories. A common approach to constructing CLFs is to consider the family of quadratic functions…
View article: Rapid Approximation of Low-Thrust Spacecraft Reachable Sets within Complex Two-Body and Cislunar Dynamics
Rapid Approximation of Low-Thrust Spacecraft Reachable Sets within Complex Two-Body and Cislunar Dynamics Open
The reachable set of controlled dynamical systems is the set of all reachable states from an initial condition over a certain time horizon, subject to operational constraints and exogenous disturbances. In astrodynamics, rapid approximatio…
View article: Reduced Desensitization Formulation for Optimal Control Problems
Reduced Desensitization Formulation for Optimal Control Problems Open
Solutions to nonlinear optimal control problems (OCPs) exhibit dispersions under model uncertainties and it is desirable to generate optimal solutions that exhibit less sensitivity to model uncertainties. We propose a novel solution desens…
View article: Acceleration-Based Switching Surfaces for Impulsive Trajectory Design Between Cislunar Libration Point Orbits
Acceleration-Based Switching Surfaces for Impulsive Trajectory Design Between Cislunar Libration Point Orbits Open
A method is proposed to generate an initial guess for impulsive trajectory design in the circular restricted three-body problem. The method uses acceleration-based switching surfaces to obtain near-impulsive solutions. A numerical continua…
View article: Rapid Determination of Low-Thrust Spacecraft Reachable Sets in Two-Body and Cislunar Problems
Rapid Determination of Low-Thrust Spacecraft Reachable Sets in Two-Body and Cislunar Problems Open
The reachable set of controlled dynamical systems consist of the set of all possible reachable states from an initial condition, over a certain period of time under various control and operation constraints and exogenous disturbances. For …
View article: Minimum-Time Trajectory Optimization With Data-Based Models: A Linear Programming Approach
Minimum-Time Trajectory Optimization With Data-Based Models: A Linear Programming Approach Open
In this paper, we develop a computationally-efficient approach to minimum-time trajectory optimization using input-output data-based models, to produce an end-to-end data-to-control solution to time-optimal planning/control of dynamic syst…
View article: L2 Norm-Based Control Regularization for Solving Optimal Control Problems
L2 Norm-Based Control Regularization for Solving Optimal Control Problems Open
Solutions to practical optimal control problems (OCPs) may consist of control profiles that switch between control limits or assume values interior to their admissible set, either due to activation of inequality state path constraints or e…
View article: Optimal Control of Wave Energy Converters Using Epsilon-Trig Regularization Method
Optimal Control of Wave Energy Converters Using Epsilon-Trig Regularization Method Open
The wave energy converter (WEC) devices provide access to a renewable energy source. Developing control strategies to harvest maximum wave energy requires solving a constrained optimal control problem. It is shown that singular control arc…
View article: Solving Singular Control Problems using Uniform Trigonometrization Method
Solving Singular Control Problems using Uniform Trigonometrization Method Open
This study investigates the application of a recently developed construct, the Uniform Trigonometrization Method (UTM), to the singular control problems in chemical engineering. The UTM involves minimal modifications to the original proble…
View article: Quad-Rotor Flight Simulation in Realistic Atmospheric Conditions
Quad-Rotor Flight Simulation in Realistic Atmospheric Conditions Open
In trajectory planning and control design for unmanned air vehicles, highly simplified models are typically used to represent the vehicle dynamics and the operating environment. The goal of this work is to perform real-time, but realistic …
View article: A novel approach for optimal trajectory design with multiple operation modes of propulsion system, part 1
A novel approach for optimal trajectory design with multiple operation modes of propulsion system, part 1 Open
View article: A novel approach for optimal trajectory design with multiple operation modes of propulsion system, part 2
A novel approach for optimal trajectory design with multiple operation modes of propulsion system, part 2 Open
View article: How Many Impulses Redux
How Many Impulses Redux Open
A central problem in orbit transfer optimization is to determine the number, time, direction, and magnitude of velocity impulses that minimize the total impulse. This problem was posed in 1967 by T. N. Edelbaum, and while notable advances …
View article: Survey of prognostics methods for condition-based maintenance in engineering systems
Survey of prognostics methods for condition-based maintenance in engineering systems Open
It is not surprising that the idea of efficient maintenance algorithms (originally motivated by strict emission regulations, and now driven by safety issues, logistics and customer satisfaction) has culminated in the so-called condition-ba…
View article: Entry Trajectory Optimization for Mars Science Laboratory Class Missions\n Using Indirect Unified Trigonometrization Method
Entry Trajectory Optimization for Mars Science Laboratory Class Missions\n Using Indirect Unified Trigonometrization Method Open
Application of traditional indirect optimization methods to optimal control\nproblems (OCPs) with control and state path constraints is not a\nstraightforward task. However, recent advances in regularization techniques and\nnumerical conti…
View article: Entry Trajectory Optimization for Mars Science Laboratory Class Missions Using Indirect Unified Trigonometrization Method
Entry Trajectory Optimization for Mars Science Laboratory Class Missions Using Indirect Unified Trigonometrization Method Open
Application of traditional indirect optimization methods to optimal control problems (OCPs) with control and state path constraints is not a straightforward task. However, recent advances in regularization techniques and numerical continua…
View article: Optimal Control of Wave Energy Converters Using Epsilon-Trig\n Regularization Method
Optimal Control of Wave Energy Converters Using Epsilon-Trig\n Regularization Method Open
The wave energy converter (WEC) devices provide access to a renewable energy\nsource. Developing control strategies to harvest maximum wave energy requires\nsolving a constrained optimal control problem. It is shown that singular\ncontrol …
View article: A Novel Approach for Optimal Trajectory Design with Multiple Operation\n Modes of Propulsion System, Part 1
A Novel Approach for Optimal Trajectory Design with Multiple Operation\n Modes of Propulsion System, Part 1 Open
Efficient performance of a number of engineering systems is achieved through\ndifferent modes of operation - yielding systems described as "hybrid",\ncontaining both real-valued and discrete decision variables. Prominent examples\nof such …
View article: How Many Impulses Redux
How Many Impulses Redux Open
A central problem in orbit transfer optimization is to determine the number, time, direction and magnitude of velocity impulses that minimize the total impulse. This problem was posed in 1967 by T. N. Edelbaum, and while notable advances h…