26 research outputs found
Priority-based intersection management with kinodynamic constraints
We consider the problem of coordinating a collection of robots at an
intersection area taking into account dynamical constraints due to actuator
limitations. We adopt the coordination space approach, which is standard in
multiple robot motion planning. Assuming the priorities between robots are
assigned in advance and the existence of a collision-free trajectory respecting
those priorities, we propose a provably safe trajectory planner satisfying
kinodynamic constraints. The algorithm is shown to run in real time and to
return safe (collision-free) trajectories. Simulation results on synthetic data
illustrate the benefits of the approach.Comment: to be presented at ECC2014; 6 page
Pareto Optimal Strategies for Event Triggered Estimation
Although resource-limited networked autonomous systems must be able to
efficiently and effectively accomplish tasks, better conservation of resources
often results in worse task performance. We specifically address the problem of
finding strategies for managing measurement communication costs between agents.
A well understood technique for trading off communication costs with estimation
accuracy is event triggering (ET), where measurements are only communicated
when useful, e.g., when Kalman filter innovations exceed some threshold. In the
absence of measurements, agents can use implicit information to achieve results
almost as well as when explicit data is always communicated. However, there are
no methods for setting this threshold with formal guarantees on task
performance. We fill this gap by developing a novel belief space discretization
technique to abstract a continuous space dynamics model for ET estimation to a
discrete Markov decision process, which scalably accommodates
threshold-sensitive ET estimator error covariances. We then apply an existing
probabilistic trade-off analysis tool to find the set of all optimal trade-offs
between resource consumption and task performance. From this set, an ET
threshold selection strategy is extracted. Simulated results show our approach
identifies non-trivial trade-offs between performance and energy savings, with
only modest computational effort.Comment: 8 pages, accepted to IEEE Conference on Decision and Control 202
Priority-based coordination of robots
20 pagesThis paper addresses the problem of coordinating multiple robots travelling through an intersection along fixed paths with positive velocities and kinodynamic constraints. The approach relies on a novel tool: a priority graph that encodes the relative order of the robots at the intersection. The overall planning approach can be decomposed into two key components as follows. The entry of robots into the intersection is managed by an intersection controller that assigns priorities. Within the intersection area, robots are controlled by a control law that preserves assigned priorities, avoids collisions, and is robust to unexpected decelerations of some robots occurring randomly
On Provably Safe and Live Multirobot Coordination With Online Goal Posting
A standing challenge in multirobot systems is to realize safe and efficient motion planning and coordination methods that are capable of accounting for uncertainties and contingencies. The challenge is rendered harder by the fact that robots may be heterogeneous and that their plans may be posted asynchronously. Most existing approaches require constraints on the infrastructure or unrealistic assumptions on robot models. In this article, we propose a centralized, loosely-coupled supervisory controller that overcomes these limitations. The approach responds to newly posed constraints and uncertainties during trajectory execution, ensuring at all times that planned robot trajectories remain kinodynamically feasible, that the fleet is in a safe state, and that there are no deadlocks or livelocks. This is achieved without the need for hand-coded rules, fixed robot priorities, or environment modification. We formally state all relevant properties of robot behavior in the most general terms possible, without assuming particular robot models or environments, and provide both formal and empirical proof that the proposed fleet control algorithms guarantee safety and liveness
Computational intelligence approaches to robotics, automation, and control [Volume guest editors]
No abstract available
Geodesics in CAT(0) Cubical Complexes
We describe an algorithm to compute the geodesics in an arbitrary CAT(0)
cubical complex. A key tool is a correspondence between cubical complexes of
global non-positive curvature and posets with inconsistent pairs. This
correspondence also gives an explicit realization of such a complex as the
state complex of a reconfigurable system, and a way to embed any interval in
the integer lattice cubing of its dimension.Comment: 27 pages, 7 figure
Homological Algebra and Its Application: A Descriptive Study
Algebra has been used to define and answer issues in almost every field of mathematics, science, and engineering. Homological algebra depends largely on computable algebraic invariants to categorise diverse mathematical structures, such as topological, geometrical, arithmetical, and algebraic (up to certain equivalences). String theory and quantum theory, in particular, have shown it to be of crucial importance in addressing difficult physics questions. Geometric, topological and algebraic algebraic techniques to the study of homology are to be introduced in this research. Homology theory in abelian categories and a category theory are covered. the n-fold extension functors EXTn (-,-) , the torsion functors TORn (-,-), Algebraic geometry, derived functor theory, simplicial and singular homology theory, group co-homology theory, the sheaf theory, the sheaf co-homology, and the l-adic co-homology, as well as a demonstration of its applicability in representation theory