scholarly journals Sampling-based methods for factored task and motion planning

2018 ◽  
Vol 37 (13-14) ◽  
pp. 1796-1825 ◽  
Author(s):  
Caelan Reed Garrett ◽  
Tomás Lozano-Pérez ◽  
Leslie Pack Kaelbling
Keyword(s):  
Motion Planning ◽  
General Purpose ◽  
State Transitions ◽  
Transition Systems ◽  
Hybrid State ◽  
Time Planning ◽  
And Control ◽  
Planning Problems ◽  
Domain Independent

This paper presents a general-purpose formulation of a large class of discrete-time planning problems, with hybrid state and control-spaces, as factored transition systems. Factoring allows state transitions to be described as the intersection of several constraints each affecting a subset of the state and control variables. Robotic manipulation problems with many movable objects involve constraints that only affect several variables at a time and therefore exhibit large amounts of factoring. We develop a theoretical framework for solving factored transition systems with sampling-based algorithms. The framework characterizes conditions on the submanifold in which solutions lie, leading to a characterization of robust feasibility that incorporates dimensionality-reducing constraints. It then connects those conditions to corresponding conditional samplers that can be composed to produce values on this submanifold. We present two domain-independent, probabilistically complete planning algorithms that take, as input, a set of conditional samplers. We demonstrate the empirical efficiency of these algorithms on a set of challenging task and motion planning problems involving picking, placing, and pushing.

AGENTS for cooperating expert systems in concurrent engineering design

1993 ◽  
Vol 7 (3) ◽  
pp. 145-158 ◽  
Author(s):  
Guo Q. Huang ◽  
John A. Brandon
Keyword(s):  
Expert Systems ◽  
Engineering Design ◽  
Concurrent Engineering ◽  
General Purpose ◽  
Main Theme ◽  
Computer Tools ◽  
System A ◽  
And Control ◽  
Domain Independent

A main theme of concurrent engineering is the effective communication between relevant disciplines. Any computer tools for concurrent engineering must provide sufficient constructs and strategies for this purpose. This paper describes the AGENTS system, a domain-independent general-purpose Object-Oriented Prolog language for cooperating expert systems in concurrent engineering design. Emphasis is placed on demonstrating the use of the AGENTS constructs for distributed knowledge representation and the cooperation strategies for communication, collaboration, conflict resolution, and control. A simple case study is presented to illustrate the balance between simplicity and flexibility.

Motion planning of the trident snake robot equipped with passive or active wheels

2012 ◽  
Vol 60 (3) ◽  
pp. 547-555 ◽  
Author(s):  
D. Paszuk ◽  
K. Tchoń ◽  
Z. Pietrowska
Keyword(s):  
Control System ◽  
Motion Planning ◽  
Computer Simulations ◽  
Configuration Space ◽  
Snake Robot ◽  
System Representation ◽  
And Control ◽  
Planning Problems ◽  
Jacobian Algorithm ◽  
Space Approach

Abstract We study the kinematics of the trident snake robot equipped with either active joints and passive wheels or passive joints and active wheels. A control system representation of the kinematics is derived, and control singularities examined. Two motion planning problems are addressed, corresponding to diverse ways of controlling the robot, and solved by means of the endogenous configuration space approach. The constraints imposed by the presence of control singularities are handled using the imbalanced Jacobian algorithm assisted by an auxiliary feedback. Performance of the motion planning algorithms is demonstrated by computer simulations.

Probabilistic Roadmaps with Higher Expressive Power

2016 ◽  
Vol 25 (04) ◽  
pp. 1650027
Author(s):  
Amol D. Mali
Keyword(s):  
Motion Planning ◽  
Expressive Power ◽  
State Transitions ◽  
Robot Motion ◽  
Multiple Robots ◽  
Probabilistic Roadmap ◽  
Temporal Intervals ◽  
Robot Configuration ◽  
Multiple Samples ◽  
Planning Problems

Sampling-based motion planning had an enormous impact on robot motion planning because of its efficiency and scalability. Many sampling-based motion planners construct a probabilistic roadmap (PRM) that captures the connectivity of the robot's free configuration space. A valid node of a PRM contains a collision-free robot configuration (also known as a sample) and a valid edge of a PRM connects two valid nodes with a collision-free path. Nodes connected by an edge are usually also required to satisfy additional requirements based on the distance between them. PRM planners use PRMs. Increasing the expressive power will allow PRMs to be used for a wider set of motion planning problems. In this paper we report on increasing the expressive power of PRMs by including the following five features in PRMs-nodes with multiple samples that need not be organized as a graph, temporal intervals of validity of nodes and edges, nodes with samples of multiple robots, special edges for the state transitions performed by humans sharing a workspace with robots, and conditional validity of samples and edges. We report on motion planning problems solvable using these new features.

scholarly journals FFRob: Leveraging symbolic planning for efficient task and motion planning

2017 ◽  
Vol 37 (1) ◽  
pp. 104-136 ◽  
Author(s):  
Caelan Reed Garrett ◽  
Tomás Lozano-Pérez ◽  
Leslie Pack Kaelbling
Keyword(s):  
Motion Planning ◽  
Heuristic Search ◽  
General Purpose ◽  
Configuration Spaces ◽  
Mobile Manipulation ◽  
Extended Action ◽  
Geometric Search ◽  
Problem Instances ◽  
Hybrid Configuration ◽  
Planning Problems

Mobile manipulation problems involving many objects are challenging to solve due to the high dimensionality and multi-modality of their hybrid configuration spaces. Planners that perform a purely geometric search are prohibitively slow for solving these problems because they are unable to factor the configuration space. Symbolic task planners can efficiently construct plans involving many variables but cannot represent the geometric and kinematic constraints required in manipulation. We present the FFRob algorithm for solving task and motion planning problems. First, we introduce extended action specification (EAS) as a general purpose planning representation that supports arbitrary predicates as conditions. We adapt existing heuristic search ideas for solving strips planning problems, particularly delete-relaxations, to solve EAS problem instances. We then apply the EAS representation and planners to manipulation problems resulting in FFRob. FFRob iteratively discretizes task and motion planning problems using batch sampling of manipulation primitives and a multi-query roadmap structure that can be conditionalized to evaluate reachability under different placements of movable objects. This structure enables the EAS planner to efficiently compute heuristics that incorporate geometric and kinematic planning constraints to give a tight estimate of the distance to the goal. Additionally, we show FFRob is probabilistically complete and has a finite expected runtime. Finally, we empirically demonstrate FFRob’s effectiveness on complex and diverse task and motion planning tasks including rearrangement planning and navigation among movable objects.

Introduction

2018 ◽  
Author(s):  
Elizabeth S. Radcliffe
Keyword(s):  
Early Modern ◽  
Historical Background ◽  
Consistent Picture ◽  
And Control ◽  
Good And Evil

The Introduction offers, first, a brief historical background to Hume’s theory of the passions, which is further elaborated in the APPENDIX. Foremost among the theses of the early modern rationalists—like Reynolds, Senault, Descartes, Cudworth, and Clarke—to which Hume is responding are: that many passions left unregulated lead to the pursuit of unsuitable objects, that reason can overcome the pernicious influence of the passions and control our actions, and that the passions are states that represent good and evil. Second, the Introduction presents a sketch of Hume’s characterization of reason and passion and his account of their relationship. Third, it explains the method of interpretation used in this book and previews its chapters. The approach is coherentist: to present an intelligible and consistent picture of Hume’s theory of passion and action, accounting for as many of the relevant texts as possible.

scholarly journals Design, Construction, and Control for an Underwater Vehicle Type Sepiida

Robotica ◽  
2020 ◽  
pp. 1-18
Author(s):  
M. Garcia ◽  
P. Castillo ◽  
E. Campos ◽  
R. Lozano
Keyword(s):  
Embedded System ◽  
Closed Loop ◽  
Underwater Vehicle ◽  
Mathematical Representation ◽  
Closed Loop System ◽  
Vehicle Type ◽  
Mathematical Equations ◽  
And Control ◽  
Design Construction

SUMMARY A novel underwater vehicle configuration with an operating principle as the Sepiida animal is presented and developed in this paper. The mathematical equations describing the movements of the vehicle are obtained using the Newton–Euler approach. An analysis of the dynamic model is done for control purposes. A prototype and its embedded system are developed for validating analytically and experimentally the proposed mathematical representation. A real-time characterization of one mass is done to relate the pitch angle with the radio of displacement of the mass. In addition, first validation of the closed-loop system is done using a linear controller.

scholarly journals Clinical characterization of dysautonomia in long COVID-19 patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nicolas Barizien ◽  
Morgan Le Guen ◽  
Stéphanie Russel ◽  
Pauline Touche ◽  
Florent Huang ◽  
...  
Keyword(s):  
Mixed Models ◽  
Repeated Measures ◽  
Physical Medicine ◽  
Persistent Symptoms ◽  
Index Changes ◽  
Changes Over Time ◽  
And Control ◽  
Testing Group ◽  
Over Time

AbstractIncreasing numbers of COVID-19 patients, continue to experience symptoms months after recovering from mild cases of COVID-19. Amongst these symptoms, several are related to neurological manifestations, including fatigue, anosmia, hypogeusia, headaches and hypoxia. However, the involvement of the autonomic nervous system, expressed by a dysautonomia, which can aggregate all these neurological symptoms has not been prominently reported. Here, we hypothesize that dysautonomia, could occur in secondary COVID-19 infection, also referred to as “long COVID” infection. 39 participants were included from December 2020 to January 2021 for assessment by the Department of physical medicine to enhance their physical capabilities: 12 participants with COVID-19 diagnosis and fatigue, 15 participants with COVID-19 diagnosis without fatigue and 12 control participants without COVID-19 diagnosis and without fatigue. Heart rate variability (HRV) during a change in position is commonly measured to diagnose autonomic dysregulation. In this cohort, to reflect HRV, parasympathetic/sympathetic balance was estimated using the NOL index, a multiparameter artificial intelligence-driven index calculated from extracted physiological signals by the PMD-200 pain monitoring system. Repeated-measures mixed-models testing group effect were performed to analyze NOL index changes over time between groups. A significant NOL index dissociation over time between long COVID-19 participants with fatigue and control participants was observed (p = 0.046). A trend towards significant NOL index dissociation over time was observed between long COVID-19 participants without fatigue and control participants (p = 0.109). No difference over time was observed between the two groups of long COVID-19 participants (p = 0.904). Long COVID-19 participants with fatigue may exhibit a dysautonomia characterized by dysregulation of the HRV, that is reflected by the NOL index measurements, compared to control participants. Dysautonomia may explain the persistent symptoms observed in long COVID-19 patients, such as fatigue and hypoxia. Trial registration: The study was approved by the Foch IRB: IRB00012437 (Approval Number: 20-12-02) on December 16, 2020.

scholarly journals The Combined Effect of Weaning Stress and Immune Activation during Pig Gestation on Serum Cytokine and Analyte Concentrations

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2274
Author(s):  
Haley E. Rymut ◽  
Laurie A. Rund ◽  
Courtni R. Bolt ◽  
Maria B. Villamil ◽  
Bruce R. Southey ◽  
...  
Keyword(s):  
Immune Activation ◽  
Management Practices ◽  
Interleukin 1 ◽  
Interleukin 2 ◽  
Blood Chemistry ◽  
Respiratory Syndrome Virus ◽  
Weaning Stress ◽  
And Control ◽  
Metabolic Hormone

Weaning stress can elicit changes in the metabolic, hormone and immune systems of pigs and interact with prolonged disruptions stemming from maternal immune activation (MIA) during gestation. The present study advances the characterization of the combined effects of weaning stress and MIA on blood chemistry, immune and hormone indicators that inform on the health of pigs. Three-week-old female and male offspring of control gilts or gilts infected with the porcine reproductive and respiratory syndrome virus were allocated to weaned or nursed groups. The anion gap and bilirubin profiles suggest that MIA enhances tolerance to the effects of weaning stress. Interleukin 1 beta and interleukin 2 were highest among weaned MIA females, and cortisol was higher among weaned relative to nursed pigs across sexes. Canonical discriminant analysis demonstrated that weaned and nursed pigs have distinct chemistry profiles, whereas MIA and control pigs have distinct cytokine profiles. The results from this study can guide management practices that recognize the effects of the interaction between MIA and weaning stress on the performance and health of pigs.

scholarly journals Genotypic Characterization of Antimicrobial Resistant Salmonella spp. Strains from Three Poultry Processing Plants in Colombia

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 491
Author(s):  
Alejandra Ramirez-Hernandez ◽  
Ana K. Carrascal-Camacho ◽  
Andrea Varón-García ◽  
Mindy M. Brashears ◽  
Marcos X. Sanchez-Plata
Keyword(s):  
Antimicrobial Resistance ◽  
Salmonella Spp ◽  
Microbial Profile ◽  
Antimicrobial Resistance Genes ◽  
Processing Plants ◽  
Poultry Processing ◽  
Paratyphi B ◽  
And Control ◽  
Sequence Types

The poultry industry in Colombia has implemented several changes and measures in chicken processing to improve sanitary operations and control pathogens’ prevalence. However, there is no official in-plant microbial profile reference data currently available throughout the processing value chains. Hence, this research aimed to study the microbial profiles and the antimicrobial resistance of Salmonella isolates in three plants. In total, 300 samples were collected in seven processing sites. Prevalence of Salmonella spp. and levels of Enterobacteriaceae were assessed. Additionally, whole-genome sequencing was conducted to characterize the isolated strains genotypically. Overall, the prevalence of Salmonella spp. in each establishment was 77%, 58% and 80% for plant A, B, and C. The mean levels of Enterobacteriaceae in the chicken rinsates were 5.03, 5.74, and 6.41 log CFU/mL for plant A, B, and C. Significant reductions were identified in the counts of post-chilling rinsate samples; however, increased levels were found in chicken parts. There were six distinct Salmonella spp. clusters with the predominant sequence types ST32 and ST28. The serotypes Infantis (54%) and Paratyphi B (25%) were the most commonly identified within the processing plants with a high abundance of antimicrobial resistance genes.

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