2,508 research outputs found
Whole-Body Exploration with a Manipulator Using Heat Equation
This paper presents a whole-body robot control method for exploring and
probing a given region of interest. The ergodic control formalism behind such
an exploration behavior consists of matching the time-averaged statistics of a
robot trajectory with the spatial statistics of the target distribution. Most
existing ergodic control approaches assume the robots/sensors as individual
point agents moving in space. We introduce an approach exploiting multiple
kinematically constrained agents on the whole-body of a robotic manipulator,
where a consensus among the agents is found for generating control actions. To
do so, we exploit an existing ergodic control formulation called heat
equation-driven area coverage (HEDAC), combining local and global exploration
on a potential field resulting from heat diffusion. Our approach extends HEDAC
to applications where robots have multiple sensors on the whole-body (such as
tactile skin) and use all sensors to optimally explore the given region. We
show that our approach increases the exploration performance in terms of
ergodicity and scales well to real-world problems using agents distributed on
multiple robot links. We compare our method with HEDAC in kinematic simulation
and demonstrate the applicability of an online exploration task with a 7-axis
Franka Emika robot.Comment: Submitted to IEEE Robotics and Automation Letter
The NASA SBIR product catalog
The purpose of this catalog is to assist small business firms in making the community aware of products emerging from their efforts in the Small Business Innovation Research (SBIR) program. It contains descriptions of some products that have advanced into Phase 3 and others that are identified as prospective products. Both lists of products in this catalog are based on information supplied by NASA SBIR contractors in responding to an invitation to be represented in this document. Generally, all products suggested by the small firms were included in order to meet the goals of information exchange for SBIR results. Of the 444 SBIR contractors NASA queried, 137 provided information on 219 products. The catalog presents the product information in the technology areas listed in the table of contents. Within each area, the products are listed in alphabetical order by product name and are given identifying numbers. Also included is an alphabetical listing of the companies that have products described. This listing cross-references the product list and provides information on the business activity of each firm. In addition, there are three indexes: one a list of firms by states, one that lists the products according to NASA Centers that managed the SBIR projects, and one that lists the products by the relevant Technical Topics utilized in NASA's annual program solicitation under which each SBIR project was selected
Parallel Quantum Rapidly-Exploring Random Trees
In this paper, we present the Parallel Quantum Rapidly-Exploring Random Tree
(Pq-RRT) algorithm, a parallel version of the Quantum Rapidly-Exploring Random
Trees (q-RRT) algorithm. Parallel Quantum RRT is a parallel quantum algorithm
formulation of a sampling-based motion planner that uses Quantum Amplitude
Amplification to search databases of reachable states for addition to a tree.
In this work we investigate how parallel quantum devices can more efficiently
search a database, as the quantum measurement process involves the collapse of
the superposition to a base state, erasing probability information and
therefore the ability to efficiently find multiple solutions. Pq-RRT uses a
manager/parallel-quantum-workers formulation, inspired by traditional parallel
motion planning, to perform simultaneous quantum searches of a feasible state
database. We present results regarding likelihoods of multiple parallel units
finding any and all solutions contained with a shared database, with and
without reachability errors, allowing efficiency predictions to be made. We
offer simulations in dense obstacle environments showing efficiency,
density/heatmap, and speed comparisons for Pq-RRT against q-RRT, classical RRT,
and classical parallel RRT. We then present Quantum Database Annealing, a
database construction strategy for Pq-RRT and q-RRT that uses a temperature
construct to define database creation over time for balancing exploration and
exploitation.Comment: 14 pages, 15 figure
Accurate Gaussian Process Distance Fields with applications to Echolocation and Mapping
This paper introduces a novel method to estimate distance fields from noisy
point clouds using Gaussian Process (GP) regression. Distance fields, or
distance functions, gained popularity for applications like point cloud
registration, odometry, SLAM, path planning, shape reconstruction, etc. A
distance field provides a continuous representation of the scene. It is defined
as the shortest distance from any query point and the closest surface. The key
concept of the proposed method is a reverting function used to turn a
GP-inferred occupancy field into an accurate distance field. The reverting
function is specific to the chosen GP kernel. This paper provides the
theoretical derivation of the proposed method and its relationship to existing
techniques. The improved accuracy compared with existing distance fields is
demonstrated with simulated experiments. The level of accuracy of the proposed
approach enables novel applications that rely on precise distance estimation.
This work presents echolocation and mapping frameworks for ultrasonic-guided
wave sensing in metallic structures. These methods leverage the proposed
distance field with a physics-based measurement model accounting for the
propagation of the ultrasonic waves in the material. Real-world experiments are
conducted to demonstrate the soundness of these frameworks
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