742,882 research outputs found
Inverse Optimal Planning for Air Traffic Control
We envision a system that concisely describes the rules of air traffic
control, assists human operators and supports dense autonomous air traffic
around commercial airports. We develop a method to learn the rules of air
traffic control from real data as a cost function via maximum entropy inverse
reinforcement learning. This cost function is used as a penalty for a
search-based motion planning method that discretizes both the control and the
state space. We illustrate the methodology by showing that our approach can
learn to imitate the airport arrival routes and separation rules of dense
commercial air traffic. The resulting trajectories are shown to be safe,
feasible, and efficient
Trajectory Replanning for Quadrotors Using Kinodynamic Search and Elastic Optimization
We focus on a replanning scenario for quadrotors where considering time
efficiency, non-static initial state and dynamical feasibility is of great
significance. We propose a real-time B-spline based kinodynamic (RBK) search
algorithm, which transforms a position-only shortest path search (such as A*
and Dijkstra) into an efficient kinodynamic search, by exploring the properties
of B-spline parameterization. The RBK search is greedy and produces a
dynamically feasible time-parameterized trajectory efficiently, which
facilitates non-static initial state of the quadrotor. To cope with the
limitation of the greedy search and the discretization induced by a grid
structure, we adopt an elastic optimization (EO) approach as a
post-optimization process, to refine the control point placement provided by
the RBK search. The EO approach finds the optimal control point placement
inside an expanded elastic tube which represents the free space, by solving a
Quadratically Constrained Quadratic Programming (QCQP) problem. We design a
receding horizon replanner based on the local control property of B-spline. A
systematic comparison of our method against two state-of-the-art methods is
provided. We integrate our replanning system with a monocular vision-based
quadrotor and validate our performance onboard.Comment: 8 pages. Published in International Conference on Robotics and
Automation (ICRA) 2018. IEEE copyrigh
Constructing General Unitary Maps from State Preparations
We present an efficient algorithm for generating unitary maps on a
-dimensional Hilbert space from a time-dependent Hamiltonian through a
combination of stochastic searches and geometric construction. The protocol is
based on the eigen-decomposition of the map. A unitary matrix can be
implemented by sequentially mapping each eigenvector to a fiducial state,
imprinting the eigenphase on that state, and mapping it back to the
eigenvector. This requires the design of only state-to-state maps generated
by control waveforms that are efficiently found by a gradient search with
computational resources that scale polynomially in . In contrast, the
complexity of a stochastic search for a single waveform that simultaneously
acts as desired on all eigenvectors scales exponentially in . We extend this
construction to design maps on an -dimensional subspace of the Hilbert space
using only stochastic searches. Additionally, we show how these techniques
can be used to control atomic spins in the ground electronic hyperfine manifold
of alkali atoms in order to implement general qudit logic gates as well to
perform a simple form of error correction on an embedded qubit.Comment: 9 pages, 3 figure
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