144 research outputs found
Robust Visual Localization of a UAV over a Pipe-Rack Based on the Lie Group SE(3)
Visual inspection and maintenance ofindustrialpipes using robots represent an emerging application in Oil Gas and refinery facilities. In this domain, we present a pose tracking system based on a single camera sensor to localize an unmanned aerial vehicle operating over a pipe-rack to carry out inspection activities. We propose a unified framework based on the Lie group SE(3) which allows the simultaneous estimation of the pose of the UAV along with some parameters of the pipe-rack model. Numerical simulations have been performed to demonstrate the effectiveness of the proposed approach
Control of the TORA System through the IDA-PBC without Explicit Solution of Matching Equations
This paper presents the control of a translational oscillator with a rotational actuator (TORA) system, in full gravity, through the interconnection and damping assignment passivity-based control (IDA-PBC). The sought goal is to control the underactuated TORA system while reducing the complexity in solving the partial differential equations coming out from the so-called matching equations, which arise from the IDA-PBC. The performance of the designed controller is illustrated through numerical simulations
Gait generation for underactuated compass-like robots using dissipative forces in the controller
This work addresses the problem of gait generation in underactuated compass-like biped robots using dissipative forces in the controller. Three different controllers are presented. The first one is a simultaneous interconnection and damping assignment passivity-based control with dissipative forces. The second one is an energy pumping-and-damping control, while the third one is an energy pumping or damping control action. Numerical case studies, comparisons, and critical discussions evaluate the performance of the proposed approaches
Metabolic Effects of Avocado/Soy Unsaponifiables on Articular Chondrocytes
Avocado/soy unsaponifiable (ASU) components are reported to have a chondroprotective effect by virtue of anti-inflammatory and proanabolic effects on articular chondrocytes. The identity of the active component(s) remains unknown. In general, sterols, the major component of unsaponifiable plant material have been demonstrated to be anti-inflammatory in vitro and in animal models. These studies were designed to clarify whether the sterol content of ASU preparations were the primary contributors to biological activity in articular chondrocytes. ASU samples were analyzed by high pressure liquid chromatography (HPLC) and GC mass spectrometry. The sterol content was normalized between diverse samples prior to in vitro testing on bovine chondrocytes. Anabolic activity was monitored by uptake of 35-sulfate into proteoglycans and quantitation of labeled hydroxyproline and proline content after incubation with labeled proline. Anti-inflammatory activity was assayed by measuring reduction of interleukin-1 (IL-1)-induced synthesis of PGE2 and metalloproteases and release of label from tissue prelabeled with S-35.All ASU samples exerted a similar time-dependent up-regulation of 35-sulfate uptake in bovine cells reaching a maximum of greater than 100% after 72 h at sterol doses of 1–10 μg/ml. Non-collagenous protein (NCP) and collagen synthesis were similarly up-regulated. All ASU were equally effective in dose dependently inhibiting IL-1-induced MMP-3 activity (23–37%), labeled sulfate release (15–23%) and PGE2 synthesis (45–58%). Up-regulation of glycosaminoglycan and collagen synthesis and reduction of IL-1 effects in cartilage are consistent with chondroprotective activity. The similarity of activity of ASU from diverse sources when tested at equal sterol levels suggests sterols are important for biologic effects in articular chondrocytes
Bayesian optimization approach to input shaper design for flexible beam vibration suppression
This paper tackles the problem of suppressing vibrations of a flexible beam mounted on a mobile robot for inspection purposes. The adopted approach is an input shaper design along with Bayesian optimization. The latter methodology is employed to find out the optimal shaping parameter, taking into account non-ideal behaviors as controller hysteresis and time delays. Experimental results bolster the performance of the proposed approach
Modelling and control of a variable-length flexible beam on inspection ground robot
Stabilising an inverted pendulum on a cart is a well-known control problem. This paper proposes the mechanical and control design for solving the oscillation problem of a variable-length flexible beam mounted on a mobile robot. The system under consideration is the robot PovRob, used at the European Organization for Nuclear Research (CERN) for visual and remote inspection tasks of particle accelerators. The flexible beam mounted on the robot houses cameras and sensors. The innovative aspect of the approach concerns the use of actuated masses mounted at the end of the rod, which induces an impulsive moment due to their inertia and angular acceleration. The modelling of the flexible rod has been suitably simplified in a lumped-parameter system, with dynamic parameters related to the rod’s flexibility. A linearisation of the dynamic model allows a linear-quadratic control to stabilise the system. Experimental results support the identification and the validation of the dynamic model, while simulation results evaluate the performances of the designed control law
A Flexible Robotic Depalletizing System for Supermarket Logistics
Depalletizing robotic systems are commonly deployed to automatize and speed-up parts of logistic processes. Despite this, the necessity to adapt the preexisting logistic processes to the automatic systems often impairs the application of such robotic solutions to small business realities like supermarkets. In this work we propose a robotic depalletizing system designed to be easily integrated into supermarket logistic processes. The system has to schedule, monitor and adapt the depalletizing process considering both on-line perceptual information given by non-invasive sensors and constraints provided by the high-level management system or by a supervising user. We describe the overall system discussing two case studies in the context of a supermarket logistic process. We show how the proposed system can manage multiple depalletizing strategies and multiple logistic requests
A Reconfigurable Gripper for Robotic Autonomous Depalletizing in Supermarket Logistics
Automatic depalletizing is becoming a practice widely applied in warehouses to automatize and speed-up logistics. On the other hand, the necessity to adapt the preexisting logistic lines to a custom automatic system can be a limit for the application of robotic solutions into smaller facilities like supermarkets. In this work, we tackle this issue by proposing a flexible and adaptive gripper for robotic depalletizing. The gripper is designed to be assembled on the end-tip of an industrial robotic arm. A novel patent-pending mechanism allows grasping boxes and products from both the upper and the lateral side enabling the depalletizing of boxes with complex shape. Moreover, the gripper is reconfigurable with five actuated degrees of freedom, that are automatically controlled using the embedded sensors to adapt grasping to different shapes and weights
RGB-D Recognition and Localization of Cases for Robotic Depalletizing in Supermarkets
Integrating a robotic system into the depalletizing process of a supermarket demands a high level of autonomy, based on strong perceptive capabilities. This letter presents a system for detection, recognition, and localization of heterogeneous cases in a depalletizing robotic cell, using a single RGB-D camera. Such a system integrates apriori information on the content of the pallet with data from the RGB-D camera, exploiting a sequence of 2D and 3D model-based computer-vision algorithms. The effectiveness of the proposed methodology is assessed in an experiment where multiple cases and pallet configurations are considered. Finally, a complete depalletizing process is shown
Visual control through narrow passages for an omnidirectional wheeled robot
Robotic systems are gradually replacing human intervention in dangerous facilities to improve human safety and prevent risky situations. In this domain, our work addresses the problem of autonomous crossing narrow passages in a semi-structured (i.e., partially-known) environment. In particular, we focus on the CERN’s Super Proton Synchrotron particle accelerator, where a mobile robot platform is equipped with a lightweight arm to perform measurements, inspection, and maintenance operations. The proposed approach leverages an image-based visual servoing strategy that exploits computer vision to detect and track known geometries defining narrow passage gates. The effectiveness of the proposed approach has been demonstrated in a realistic mock-up
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