656 research outputs found

    Vision-guided gripping of a cylinder

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    The motivation for vision-guided servoing is taken from tasks in automated or telerobotic space assembly and construction. Vision-guided servoing requires the ability to perform rapid pose estimates and provide predictive feature tracking. Monocular information from a gripper-mounted camera is used to servo the gripper to grasp a cylinder. The procedure is divided into recognition and servo phases. The recognition stage verifies the presence of a cylinder in the camera field of view. Then an initial pose estimate is computed and uncluttered scan regions are selected. The servo phase processes only the selected scan regions of the image. Given the knowledge, from the recognition phase, that there is a cylinder in the image and knowing the radius of the cylinder, 4 of the 6 pose parameters can be estimated with minimal computation. The relative motion of the cylinder is obtained by using the current pose and prior pose estimates. The motion information is then used to generate a predictive feature-based trajectory for the path of the gripper

    Hectospec, the MMT's 300 Optical Fiber-Fed Spectrograph

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    The Hectospec is a 300 optical fiber fed spectrograph commissioned at the MMT in the spring of 2004. A pair of high-speed six-axis robots move the 300 fiber buttons between observing configurations within ~300 s and to an accuracy ~25 microns. The optical fibers run for 26 m between the MMT's focal surface and the bench spectrograph operating at R~1000-2000. Another high dispersion bench spectrograph offering R~5,000, Hectochelle, is also available. The system throughput, including all losses in the telescope optics, fibers, and spectrograph peaks at ~10% at the grating blaze in 1" FWHM seeing. Correcting for aperture losses at the 1.5" diameter fiber entrance aperture, the system throughput peaks at ∼\sim17%. Hectospec has proven to be a workhorse instrument at the MMT. Hectospec and Hectochelle together were scheduled for 1/3 of the available nights since its commissioning. Hectospec has returned \~60,000 reduced spectra for 16 scientific programs during its first year of operation.Comment: 68 pages, 28 figures, to appear in December 2005 PAS

    Tactile Sensing with Accelerometers in Prehensile Grippers for Robots

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    This is the author’s version of a work that was accepted for publication in Mechatronics. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Mechatronics, Vol. 33, (2016)] DOI 10.1016/j.mechatronics.2015.11.007.Several pneumatic grippers with accelerometers attached to their fingers have been developed and tested. The first gripper is able to classify the hardness of different cylinders, estimate the pneumatic pressure, monitor the position and speed of the gripper fingers, and study the phases of the action of grasping and the influence of the relative position between the gripper and the cylinders. The other grippers manipulate and assess the firmness of eggplants and mangoes. To achieve a gentle manipulation, the grippers employ fingers with several degrees of freedom in different configurations and have a membrane filled with a fluid that allows their hardness to be controlled by means of the jamming transition of the granular fluid inside it. To assess the firmness of eggplants and mangoes and avoid the influence of the relative position between product and gripper, the firmness is estimated while the products are being held by the fingers. Better performance of the accelerometers is achieved when the finger employs the granular fluid. The article presents methods for designing grippers capable of assessing the firmness of irregular products with accelerometers. At the same time, it also studies the possibilities that accelerometers, attached to different pneumatic robot gripper fingers, offer as tactile sensors. (C) 2015 Elsevier Ltd. All rights reserved.This research is supported by the MANI-DACSA project (Grant number RTA2012-00062-C04-02), which is partially funded by the Spanish Government (Ministerio de Economia y Competitividad.).Blanes Campos, C.; Mellado Arteche, M.; Beltrán Beltrán, P. (2016). Tactile Sensing with Accelerometers in Prehensile Grippers for Robots. Mechatronics. 33:1-12. https://doi.org/10.1016/j.mechatronics.2015.11.007S1123

    Automation of a complex transfer operation using a polar manipulator

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    Purpose – The objective of this paper included developing a polar robot (SPBot) for rotating and transferring car engine block (CEB) around and along two different axes in a confined workspace envelope. Design/methodology/approach – The complex transfer operations of the CEB requires sweeping complete surface of the half sphere, and thus a polar robot is best suited to such a task in a confined space. Considering the limited space for this operation, a specially designed manipulator is built comprising 2 degrees of freedom driven by electrical servo motors. Also due to the special form of CEB, an especially designed pneumatic gripper is developed. Kinematics models, static and dynamic equations, together with trajectory planning for such a manipulator are described. Findings – The high-speed complex transfer in a limited environment is successfully implemented. Originality/value – The developed polar robot provides for complex transfer operations that significantly increases the speed of the product line and thus reducing the cycle time from 60?s using manpower to just 20?s using the robot

    INTEGRATION OF ROBOTIC AND ELECTRO-PNEUMATIC SYSTEMS USING ADVANCED CONTROL AND COMMUNICATION SCHEMES

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    Modern industrial automation systems are designed by interconnecting various subsystems which work together to perform a process. The thesis project aims to integrate fragmented subsystems into a flexible and reconfigurable system through advanced communication protocols and perform a process to demonstrate the effectiveness of interconnected systems. The system consists of three six-axis robots, one electro-pneumatic robot, and two conveyors connected using EthernetIP communication and hardwired connections. The interconnected system works together to perform machining of a workpiece using advanced control methods of CAD to robot path generation, central control through a PLC, and process control through HMI. Standardized programming blocks and HMI interfaces were developed to make the system highly reconfigurable and flexible for any future projects. The knowledge gained from the project is used to create lab manuals to educate students about communication and control methods for systems integration

    Design and control of a multi-fingered robot hand provided with tactile feedback

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    The design, construction, control and application of a three fingered robot hand with nine degrees of freedom and built-in multi-component force sensors is described. The adopted gripper kinematics are justified and optimized with respect to grasping and manipulation flexibility. The hand was constructed with miniature motor drive systems imbedded into the fingers. The control is hierarchically structured and is implemented on a simple PC-AT computer. The hand's dexterity and intelligence are demonstrated with some experiments

    Development of a picking and dropping mechanism for protray grown vegetable seedlings

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    In India, manual transplanting of vegetable seedlings was the commonly adopted method for raising vegetable crops, but it is laborious, time-consuming and costly. Therefore, mechanical transplanters are developed to overcome the problems in manual transplanting. The present work was to develop multiple seedlings picking and transferring mechanism for protray grown vegetable seedlings. Tomato (Solanum lycopersicum), chilli (Capsicum annuum) and brinjal (Solanum melongena) seedlings were raised in portrays with coir pith as a growth media and used for transplanting operation. The mechanism was to pick seven numbers of seedlings in one row at a time and transfer them into lateral conveying system, which could deliver the seedlings one by one on to the ground at regular interval. Programmable Logic Controller was used to controlling entire operations of seedlings picking and dropping. At the time of evaluation, a totally 196 number of seedlings were used with 98 cell protray. From the test results, the success rate of 89.28 per cent, missing seedling of 3.57 per cent, damaged seedling of 4.08 per cent, seedling delivering failure of 3.06 per cent were recorded for tomato seedlings. Similarly, in chilli and brinjal the success rate of 95.40 and 91.83 per cent, the missing seedling of 2.04 and 2.55 per cent, damaged seedling of 1.53 and 3.06 per cent and seedling delivering failure of 1.02 and 2.55 per cent respectively were observed. Transplanting frequency of developed mechanism was 2520 seedlings h-1.   As a whole, this work was able to develop a working model of vegetable seedling transplanting mechanism, which can eject seven seedlings at a time from portray cell and transfer them into the slotted conveyor.

    Integration of an automatic storage and retrieval system (ASRS) in a discrete-part automation system

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    This technical report describes the work carried out in a project within the ERASMUS programme. The objective of this project was the Integration of an Automatic Warehouse in a Discrete-Part Automation System. The discrete-part automation system located at the LASCRI (Critical Systems) laboratory at ISEP was extended with automatic storage and retrieval of the manufacturing parts, through the integration of an automatic warehouse and an automatic guided vehicle (AGV)
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