1,519 research outputs found
Game Theoretic Strategies for Spacecraft Rendezvous and Motion Synchronization
The rendezvous problem between two active spacecraft is formulated as a two player
nonzero-sum differential game. The local-vertical local-horizontal (LVLH) rotating
reference frame is used to describe the dynamics of the game. Linear quadratic cooperative
and noncooperative differential games are applied to obtain a feedback control law. A
comparison between Pareto and Nash equilibria was then performed. The state-dependent
Riccati equation (SDRE) method is applied to extend the Linear Quadratic differential game
theory to obtain a feedback controller in the case of nonlinear relative motion dynamics.
Finally, a multiplayer sequential game strategy is synthesized to extend the control law to the
relative motion synchronization of multiple vehicles
Realistic Guidance Performance during Lunar Rendezvous with Third Body Perturbation
The paper describes the performance of a guidance law based on the Adjoint and SDRE
methods in presence of reality representative models of sensors and actuators during the
rendezvous phase of the proposed Heracles mission to the Moon. In recent years, the increased
interest in returning to the Moon has motivated the necessity to develop accurate models for the
analysis of missions that takes into account realistic system components. The paper reviews the
mission’s details, the rendezvous/berthing guidance algorithm with third body perturbation,
and sensor’s and actuators state of the art models. A Montecarlo analysis is used to validate
the models in order to satisfy the safety of the trajectory. The results show that the proposed
guidance and control are capable of maintaining safe relative motion between the vehicles
Relative Motion Equations in the local-vertical local-Horizon Frame for Rendezvous in lunar Orbits
In this paper, a set of equations for relative motion description in lunar orbits is
presented. The local-vertical local-horizon frame is selected to describe the relative
dynamics of a chaser approaching a target in lunar orbit, allowing the development
of relative guidance and navigation systems for rendezvous and docking.
The model considers the Earth and Moon gravitational influence on the two spacecraft,
which are assumed to have negligible masses. The proposed equations are
intended for the study of rendezvous missions with a future cis-lunar space station,
whose development is currently investigated by several space agencies as the next
step for space exploration
Distributed Cooperative Deployment of Heterogeneous Autonomous Agents: A Pareto Suboptimal Approach
The paper presents a distributed cooperative control law for autonomous deployment of a team of heterogeneous agents. Deployment problems deal with the coordination of groups of agents in order to cover one or more assigned areas of the operational space. In particular, we consider a team composed by agents with different dynamics, sensing capabilities, and resources available for the deployment. Sensing heterogeneity is addressed by means of the descriptor function framework, an abstraction that provides a set of mathematical tools for describing both agent sensing capabilities and the desired deployment. A distributed cooperative control law is then formally derived nding a
suboptimal solution of a cooperative dierential game, where the agents are interested in achieving the requested deployment, while optimizing the resources usage according to their dynamics. The control law eectiveness is proven by theoretical arguments, and supported by numerical simulations
Synchronization Patterns in Networks of Kuramoto Oscillators: A Geometric Approach for Analysis and Control
Synchronization is crucial for the correct functionality of many natural and
man-made complex systems. In this work we characterize the formation of
synchronization patterns in networks of Kuramoto oscillators. Specifically, we
reveal conditions on the network weights and structure and on the oscillators'
natural frequencies that allow the phases of a group of oscillators to evolve
cohesively, yet independently from the phases of oscillators in different
clusters. Our conditions are applicable to general directed and weighted
networks of heterogeneous oscillators. Surprisingly, although the oscillators
exhibit nonlinear dynamics, our approach relies entirely on tools from linear
algebra and graph theory. Further, we develop a control mechanism to determine
the smallest (as measured by the Frobenius norm) network perturbation to ensure
the formation of a desired synchronization pattern. Our procedure allows us to
constrain the set of edges that can be modified, thus enforcing the sparsity
structure of the network perturbation. The results are validated through a set
of numerical examples
Distributed Real-Time Hardware- and Man-in-the-loop Simulation for the ICARO II Unmanned Systems Autopilot
The autopilot market for small and research UAVs offers several products, but most of them,
although widely configurable or even open-source, do not constitute a practical and safe development system
for custom guidance, navigation and control systems. The ICARO project aims at providing the small UAV
community with a valid autopilot alternative. The ICARO autopilot exploits rapid control system prototyping
techniques and immersive manned simulation with the possibility of testing the autopilot using the Hardware-
In-the-Loop (HIL) approach. This paper describes the hardware-in-the-loop and man-in-the-loop simulator for
the ICARO II platform together with the synchronization protocol we developed to keep simulator and
autopilot synchronized. Experimental evidence of the effectiveness of the synchronization protocol is given
Cooperative Control for Multiple Autonomous Vehicles Using Descriptor Functions
The paper presents a novel methodology for the control management of a swarm of autonomous vehicles. The vehicles, or agents, may have different skills, and be employed for different missions. The methodology is based on the definition of descriptor functions that model the capabilities of the single agent and each task or mission. The swarm motion is controlled by minimizing a suitable norm of the error between agents’ descriptor functions and other descriptor functions which models the entire mission. The validity of the proposed technique is tested via numerical simulation, using different task assignment scenarios
Swarm Obstacle and Collision Avoidance using Descriptor Functions
The descriptor function framework is used as tool
for the control management of a swarm of dynamic agents. In
this framework, a provision is made for obstacle and collision
avoidance, thus improving the potential of the methodology
from previous results. Obstacle and collision avoidance terms
are added to the overall mission performance index, and the
resulting control law moves the agents along obstacle and
collision free trajectories. The analytical derivation is validated
via numerical simulations
Synchronization Patterns in Networks of Kuramoto Oscillators: A Geometric Approach for Analysis and Control
Synchronization is crucial for the correct functionality of many natural and man-made complex systems. In
this work we characterize the formation of synchronization
patterns in networks of Kuramoto oscillators. Specifically, we
reveal conditions on the network weights and structure and on
the oscillators’ natural frequencies that allow the phases of a
group of oscillators to evolve cohesively, yet independently from
the phases of oscillators in different clusters. Our conditions
are applicable to general directed and weighted networks of
heterogeneous oscillators. Surprisingly, although the oscillators
exhibit nonlinear dynamics, our approach relies entirely on
tools from linear algebra and graph theory. Further, we develop
a control mechanism to determine the smallest (as measured
by the Frobenius norm) network perturbation to ensure the
formation of a desired synchronization pattern. Our procedure
allows us to constrain the set of edges that can be modified, thus
enforcing the sparsity structure of the network perturbation.
The results are validated through a set of numerical example
- …