Sadek Crisóstomo Absi Alfaro

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This paper presents an on-line tracking optimization scheme for sensor guided robotic manipulators by associating sensor information, manipulator dynamics and a path generator model. Feedback linearization-decoupling permits the use of linear SISO prediction models for the dynamics of each robot joint. Scene interpretation of CCD-camera images generates(More)
— This paper describes the implementation of a platform based on reconfigurable architecture and on concepts of virtual instrumentation and its application to the hands-free driving problem. The novelty of this approach is the use of both reconfigurable systems (for developing the car's controller) and virtual instrumentation issues for developing a(More)
The present study shows the relationship between welding quality and optical-acoustic emissions from electric arcs, during welding runs, in the GMAW-S process. Bead on plate welding tests was carried out with pre-set parameters chosen from manufacturing standards. During the welding runs interferences were induced on the welding path using paint, grease or(More)
This paper describes the implementation of a control system for hands-free driving car based on reconfigurable architectures and the virtual instrumentation concepts. The reconfigurable architecture approach means the use of an embedded microprocessor (Microblaze, Xilinx) jointly with several hardware modules, which were described in VHDL hardware(More)
Product Service Systems (PSS) and Prognostic Health Management (PHM) have so far been researched individually in different domains and as unrelated research theme. However, to guarantee the availability of the asset, which is a typical demand in some PSS contracts, it is fundamental for PSS providers to be able to properly manage the asset's lifetime(More)
Most of the inspection methods used for detection and localization of welding disturbances are based on the evaluation of some direct measurements of welding parameters. This direct measurement requires an insertion of sensors during the welding process which could somehow alter the behavior of the metallic transference. An inspection method that evaluates(More)
Associated to the weld quality, the weld bead geometry is one of the most important parameters in welding processes. It is a significant requirement in a welding project, especially in automatic welding systems where a specific width, height, or penetration of weld bead is needed. This paper presents a novel technique for real-time measuring of the width(More)
In this paper, an identification scheme via extreme learning machine neural network is proposed. The proposed identification scheme ensures the convergence of the residual state error to zero and boundedness of all associated approximation errors, even in the presence of approximation error and disturbances. Lyapunov-like analysis using Barbalat's Lemma and(More)
This paper presents the development of an FPGA-based platform for on-line discontinuity detection in a Gas Tungsten Arc Welding (GTAW) process, through the monitoring its voltaic arc, using an optical infrared sensor. The FPGA-based platform uses a hardware/software co-design approach, in which the hardware part includes a change detection peripheral, apart(More)