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1 – 2 of 2Louis‐Alain Larouche and Lionel Birglen
Adaptive grippers are versatile end effectors that mechanically adapt their shapes to the objects they seize, allowing for soft and delicate grasps while still allowing for strong…
Abstract
Purpose
Adaptive grippers are versatile end effectors that mechanically adapt their shapes to the objects they seize, allowing for soft and delicate grasps while still allowing for strong contact forces if needed and therefore they are well suited for industrial applications. The purpose of this paper is to present a software‐oriented approach to design optimal architectures of linkage‐driven adaptive (often a.k.a underactuated) fingers with three degrees of freedom.
Design/methodology/approach
The user of the software presented in this paper can design planar underactuated fingers following defined constraints. The software uses an algorithm able to compute the internal and contact forces generated, respectively, in and by the finger, it is also capable of automating the design of non‐straight links to eliminate mechanical interferences, and includes results from a topological synthesis to generate all possible architectures. The mechanisms are evaluated for many criteria such as the volume of their workspaces, stability, force isotropy, stiffness of their grasps, and compactness.
Findings
This article introduces 11 new designs of underactuated fingers for four different usages, and many of these variants are good candidates for a physical realization. One of the interesting results of this work is the recurrence of S3 variants coupled with torque amplifiers or closely resembling designs using many unrelated performance criteria.
Originality/value
This paper is the first, to the best of the authors' knowledge, to investigate the systematic design of underactuated fingers driven by linkages considering not one but dozens of mechanical architectures.
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Antoine Bres, Bruno Monsarrat, Laurent Dubourg, Lionel Birglen, Claude Perron, Mohammad Jahazi and Luc Baron
The purpose of this paper is to establish a model‐based framework allowing the simulation, analysis and optimization of friction stir welding (FSW) processes of metallic…
Abstract
Purpose
The purpose of this paper is to establish a model‐based framework allowing the simulation, analysis and optimization of friction stir welding (FSW) processes of metallic structures using industrial robots, with a particular emphasis on the assembly of aircraft components made of aerospace aluminum alloys.
Design/methodology/approach
After a first part of the work dedicated to the kinetostatic and dynamical identification of the robotic mechanical system, a complete analytical model of the robotized process is developed, incorporating a dynamic model of the industrial robot, a multi‐axes macroscopic visco‐elastic model of the FSW process and a force/position control unit of the system. These different modules are subsequently implemented in a high‐fidelity multi‐rate dynamical simulation.
Findings
The developed simulation infrastructure allowed the research team to analyze and understand the dynamic interaction between the industrial robot, the control architecture and the manufacturing process involving heavy load cases in different process configurations. Several critical process‐induced perturbations such as tool oscillations and lateral/rotational deviations are observed, analyzed, and quantified during the simulated operations.
Practical implications
The presented simulation platform will constitute one of the key technology enablers in the major research initiative carried out by NRC Aerospace in their endeavor to develop a robust robotic FSW platform, allowing both the development of optimal workcell layouts/process parameters and the validation of advanced real‐time control laws for robust handling of critical process‐induced perturbations. These deliverables will be incorporated in the resulting robotic FSW technology packaged for deployment in production environments.
Originality/value
The paper establishes the first model‐based framework allowing the high‐fidelity simulation, analysis and optimization of FSW processes using serial industrial robots.
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