211 research outputs found
Handling robot constraints within a Set-Based Multi-Task Priority Inverse Kinematics Framework
Set-Based Multi-Task Priority is a recent framework to handle inverse
kinematics for redundant structures. Both equality tasks, i.e., control
objectives to be driven to a desired value, and set-bases tasks, i.e., control
objectives to be satisfied with a set/range of values can be addressed in a
rigorous manner within a priority framework. In addition, optimization tasks,
driven by the gradient of a proper function, may be considered as well, usually
as lower priority tasks. In this paper the proper design of the tasks, their
priority and the use of a Set-Based Multi-Task Priority framework is proposed
in order to handle several constraints simultaneously in real-time. It is shown
that safety related tasks such as, e.g., joint limits or kinematic singularity,
may be properly handled by consider them both at an higher priority as
set-based task and at a lower within a proper optimization functional.
Experimental results on a 7DOF Jaco$^2
Safety-related Tasks within the Set-Based Task-Priority Inverse Kinematics Framework
In this paper we present a framework that allows the motion control of a
robotic arm automatically handling different kinds of safety-related tasks. The
developed controller is based on a Task-Priority Inverse Kinematics algorithm
that allows the manipulator's motion while respecting constraints defined
either in the joint or in the operational space in the form of equality-based
or set-based tasks. This gives the possibility to define, among the others,
tasks as joint-limits, obstacle avoidance or limiting the workspace in the
operational space. Additionally, an algorithm for the real-time computation of
the minimum distance between the manipulator and other objects in the
environment using depth measurements has been implemented, effectively allowing
obstacle avoidance tasks. Experiments with a Jaco manipulator, operating in
an environment where an RGB-D sensor is used for the obstacles detection, show
the effectiveness of the developed system
Argomenti di giurisprudenza e di scienze politiche sui quali dopo sostenuti gli esami rigorosi per ottenere la laurea in ambe le leggi nell' I. R. UniversitĂ di Pavia disputerĂ pubblicamente Chiaverini Stefano di Cremona il giorno 6 Dicembre 1850 alle ore 2 pomeridiane
A Control Architecture for Safe Trajectory Generation in Human–Robot Collaborative Settings
This paper introduces a control architecture that enables a robotic system to ensure the safety of human operators entering its workspace. The proposed method utilizes an appropriate metric to measure safety levels and adjusts the robot’s motion to maintain this metric above a minimum threshold. To guarantee safety, the robot scales down and deviates from its intended path. For redundant robots, internal motion is exploited to enhance safety levels further. The approach is incorporated into a Hierarchical Quadratic Programming control framework, allowing the robot to address other control objectives simultaneously, such as handling joint limits. Experimental results with a dual-arm mobile robot developed as part of the EU-funded CANOPIES project demonstrate the effectiveness of the proposed method. Note to Practitioners—This paper was motivated by the problem of ensuring human safety in unstructured environments shared with human operators. We propose a control architecture that allows complex dual-arm robotic systems to operate effectively in such scenarios. The devised architecture gives the robot the capability to slow down a trajectory to follow as well as to deviate from a nominal path to keep a human operator safe. We tested the devised approach in a precision farming setting; however, it can be adopted in any human-robot interaction scenario
Stability analysis for the Null-Space-based Behavioral control for multi-robot systems
Adaptive trajectory tracking for quadrotor MAVs in presence of parameter uncertainties and external disturbances
International audienceThe paper presents an adaptive trajectory track- ing control strategy for quadrotor Micro Aerial Vehicles. The proposed approach, while keeping the typical assumption of an orientation dynamics faster than the translational one, removes that of absence of external disturbances and of perfect symmetry of the vehicle. In particular, the trajectory tracking control law is made adaptive with respect to the presence of external forces and moments, and to the uncertainty of dynamic parameters as the position of the center of mass of the vehicle. A stability analysis as well as numerical simulations are provided to support the control design
An Efficient Pseudo-Inverse Solution to the Inverse Kinematic Problem for 6-Joint Manipulators
Hypo- and Hyper-Virulent Listeria monocytogenes Clones Persisting in Two Different Food Processing Plants of Central Italy
A total of 66 Listeria monocytogenes (Lm) isolated from 2013 to 2018 in a small-scale meat
processing plant and a dairy facility of Central Italy were studied. Whole Genome Sequencing
and bioinformatics analysis were used to assess the genetic relationships between the strains and
investigate persistence and virulence abilities. The biofilm forming-ability was assessed in vitro.
Cluster analysis grouped the Lm from the meat plant into three main clusters: two of them, both
belonging to CC9, persisted for years in the plant and one (CC121) was isolated in the last year of
sampling. In the dairy facility, all the strains grouped in a CC2 four-year persistent cluster. All the
studied strains carried multidrug efflux-pumps genetic determinants (sugE, mdrl, lde, norM, mepA).
CC121 also harbored the Tn6188 specific for tolerance to Benzalkonium Chloride. Only CC9 and
CC121 carried a Stress Survival Islet and presented high-level cadmium resistance genes (cadA1C1)
carried by different plasmids. They showed a greater biofilm production when compared with CC2.
All the CC2 carried a full-length inlA while CC9 and CC121 presented a Premature Stop Codon
mutation correlated with less virulence. The hypo-virulent clones CC9 and CC121 appeared the most
adapted to food-processing environments; however, even the hyper-virulent clone CC2 warningly
persisted for a long time. The identification of the main mechanisms promoting Lm persistence in a
specific food processing plant is important to provide recommendations to Food Business Operators
(FBOs) in order to remove or reduce resident Lm
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