40,309 research outputs found
Automated sequence and motion planning for robotic spatial extrusion of 3D trusses
While robotic spatial extrusion has demonstrated a new and efficient means to
fabricate 3D truss structures in architectural scale, a major challenge remains
in automatically planning extrusion sequence and robotic motion for trusses
with unconstrained topologies. This paper presents the first attempt in the
field to rigorously formulate the extrusion sequence and motion planning (SAMP)
problem, using a CSP encoding. Furthermore, this research proposes a new
hierarchical planning framework to solve the extrusion SAMP problems that
usually have a long planning horizon and 3D configuration complexity. By
decoupling sequence and motion planning, the planning framework is able to
efficiently solve the extrusion sequence, end-effector poses, joint
configurations, and transition trajectories for spatial trusses with
nonstandard topologies. This paper also presents the first detailed computation
data to reveal the runtime bottleneck on solving SAMP problems, which provides
insight and comparing baseline for future algorithmic development. Together
with the algorithmic results, this paper also presents an open-source and
modularized software implementation called Choreo that is machine-agnostic. To
demonstrate the power of this algorithmic framework, three case studies,
including real fabrication and simulation results, are presented.Comment: 24 pages, 16 figure
Identification of geometrical and elastostatic parameters of heavy industrial robots
The paper focuses on the stiffness modeling of heavy industrial robots with
gravity compensators. The main attention is paid to the identification of
geometrical and elastostatic parameters and calibration accuracy. To reduce
impact of the measurement errors, the set of manipulator configurations for
calibration experiments is optimized with respect to the proposed performance
measure related to the end-effector position accuracy. Experimental results are
presented that illustrate the advantages of the developed technique.Comment: arXiv admin note: substantial text overlap with arXiv:1311.667
Proprioceptive Robot Collision Detection through Gaussian Process Regression
This paper proposes a proprioceptive collision detection algorithm based on
Gaussian Regression. Compared to sensor-based collision detection and other
proprioceptive algorithms, the proposed approach has minimal sensing
requirements, since only the currents and the joint configurations are needed.
The algorithm extends the standard Gaussian Process models adopted in learning
the robot inverse dynamics, using a more rich set of input locations and an
ad-hoc kernel structure to model the complex and non-linear behaviors due to
frictions in quasi-static configurations. Tests performed on a Universal Robots
UR10 show the effectiveness of the proposed algorithm to detect when a
collision has occurred.Comment: Published at ACC 201
Modelling of the gravity compensators in robotic manufacturing cells
The paper deals with the modeling and identification of the gravity
compensators used in heavy industrial robots. The main attention is paid to the
geometrical parameters identification and calibration accuracy. To reduce
impact of the measurement errors, the design of calibration experiments is
used. The advantages of the developed technique are illustrated by experimental
result
Experimental External Force Estimation Using a Non-Linear Observer for 6 axes Flexible-Joint Industrial Manipulators
This paper proposes a non-linear observer to estimate not only the state (position and velocity) of links but also the external forces exerted by the robot during Friction Stir Welding (FSW) processes. The difficulty of performing this process with a robot lies in its lack of rigidity. In order to ensure a better tracking performance, the data such as real positions, velocities of links and external forces are required. However, those variations are not always measured in most industrial robots. Therefore, in this study, an observer is proposed to reconstruct those necessary parameters by using only measurements of motor side. The proposed observer is carried out on a 6 DOF flexible-joint industrial manipulator used in a FSW process.ANR-2010-SEGI-003-01-COROUSSO, French National Agenc
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