37 research outputs found

    Welding Seam Tracking Method Analysis

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    Analysis of welding seam tracking methods in automated robotic welding is presented in this paper. Analysis is performed to figure out current state of automated welding field. Robotic welding is being used in metalworking industry and allowing to increase welding precision and performance.В статье рассматриваются методы слежения за сварным швом при использовании роботизированной сварки. Анализ проводится для выяснения текущей ситуации в области автоматизированной сварки. Роботизированная сварка используется в металлообрабатывающей промышленности и позволяет увеличить точность сварки и производительность работы

    Intelligent 3D seam tracking and adaptable weld process control for robotic TIG welding

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    Tungsten Inert Gas (TIG) welding is extensively used in aerospace applications, due to its unique ability to produce higher quality welds compared to other shielded arc welding types. However, most TIG welding is performed manually and has not achieved the levels of automation that other welding techniques have. This is mostly attributed to the lack of process knowledge and adaptability to complexities, such as mismatches due to part fit-up. Recent advances in automation have enabled the use of industrial robots for complex tasks that require intelligent decision making, predominantly through sensors. Applications such as TIG welding of aerospace components require tight tolerances and need intelligent decision making capability to accommodate any unexpected variation and to carry out welding of complex geometries. Such decision making procedures must be based on the feedback about the weld profile geometry. In this thesis, a real-time position based closed loop system was developed with a six axis industrial robot (KUKA KR 16) and a laser triangulation based sensor (Micro-Epsilon Scan control 2900-25). [Continues.

    3D Visual Tracking of an Articulated Robot in Precision Automated Tasks

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    Abstract: The most compelling requirements for visual tracking systems are a high detection accuracy and an adequate processing speed. However, the combination between the two requirements in real world applications is very challenging due to the fact that more accurate tracking tasks often require longer processing times, while quicker responses for the tracking system are more prone to errors, therefore a trade-off between accuracy and speed, and vice versa is required. This paper aims to achieve the two requirements together by implementing an accurate and time efficient tracking system. In this paper, an eye-to-hand visual system that has the ability to automatically track a moving target is introduced. An enhanced Circular Hough Transform (CHT) is employed for estimating the trajectory of a spherical target in three dimensions, the colour feature of the target was carefully selected by using a new colour selection process, the process relies on the use of a colour segmentation method (Delta E) with the CHT algorithm for finding the proper colour of the tracked target, the target was attached to the six degree of freedom (DOF) robot end-effector that performs a pick-and-place task. A cooperation of two Eye-to Hand cameras with their image Averaging filters are used for obtaining clear and steady images. This paper also examines a new technique for generating and controlling the observation search window in order to increase the computational speed of the tracking system, the techniques is named Controllable Region of interest based on Circular Hough Transform (CRCHT). Moreover, a new mathematical formula is introduced for updating the depth information of the vision system during the object tracking process. For more reliable and accurate tracking, a simplex optimization technique was employed for the calculation of the parameters for camera to robotic transformation matrix. The results obtained show the applicability of the proposed approach to track the moving robot with an overall tracking error of 0.25 mm. Also, the effectiveness of CRCHT technique in saving up to 60% of the overall time required for image processing

    Industrial Robotics

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    This book covers a wide range of topics relating to advanced industrial robotics, sensors and automation technologies. Although being highly technical and complex in nature, the papers presented in this book represent some of the latest cutting edge technologies and advancements in industrial robotics technology. This book covers topics such as networking, properties of manipulators, forward and inverse robot arm kinematics, motion path-planning, machine vision and many other practical topics too numerous to list here. The authors and editor of this book wish to inspire people, especially young ones, to get involved with robotic and mechatronic engineering technology and to develop new and exciting practical applications, perhaps using the ideas and concepts presented herein

    An Investigation into a Combined Visual Servoing and Vision-Based Navigation System Robot for the Aerospace Manufacturing Industry

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    High-Value manufacturing, such as aerospace manufacturing, has been less impacted by the mainstream use of robotic automation compared to other manufacturing industries. This is due to the cost factor required when creating robotic systems which can successfully interact with such high tolerance work�pieces. This research aims to investigate the gap of robotics within high-value aerospace manufacturing, with the goal of creating a generic robotic algorithm which can effectively and optimally detect and trace a variety of aerostructure inspired workpieces. This goal was achieved by firstly developing a vision system for detecting and tracing particular features of partially-known workpieces. These workpieces var�ied in size and spatial profile, having both obtuse and acute edges. Once an effective vision system was developed, a variety of distribution-of-labour algorithms were developed, with the aim of dividing the task of tracing a work�piece between the kinematic arm and mobile base. The results showed that different distribution-of-labour algorithms performed differently, depending on the type of detected feature, specifically how vertically inclined the feature was. These results were used to develop an optimal distribution-of-labour algorithm, which could dynamically and optimally switch between different distribution-of-labour systems, to trace a workpiece both quickly and accurately. Results showed that an optimal distribution-of-labour algorithm decreased tracing time and increased accuracy in realistic aerostructure-inspired workpieces compared to just using one major algorithm, and could dynamically trace workpieces regardless of previous knowledge or spatial profile

    Design and Control of an Articulated Robotic Arm Using Visual Inspection for Replacement Activities

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    Design of robotic systems and their control for inspection and maintenance tasks is highly complex activity involving coordination of various sub-systems. In application like inspections in fusion reactor vessels and deep-mining works, a regular off-line maintenance is necessary in certain locations. Due to the hostile environments inside, robotic systems are to be deployed for such internal observations. In this regard, current work focuses on the methodology for maintenance of the first wall blanket modules in a fusion reactor vessel using a manipulator system. A design is proposed for wall tile inspections in an ideal environment in which vacuum and temperature conditions are not accounted and wall surface curvature is not accounted initially. The entire design has four important modules: (i) mathematical modelling (ii) control system design (iii) machine vision and image processing, (iv) hardware development and testing. A five- axis articulated manipulator equipped with a vision camera in eye-to-hand configuration is designed for performing the pick and place operations of the defected tiles in a systematic manner. Kinematic and dynamics analysis of the system are first carried-out and a scaled prototype is fabricated for testing various operating issues. Forward kinematics of manipulator allows in estimation of robot workspace and in knowing the singular regions during operation, while the inverse kinematics of the manipulator would be needed for real time manipulator control task. Dynamics of manipulator is required for design of model-based controllers. Interactive programs are developed in Matlab for kinematics and dynamics and three-dimensional manipulator assembly configuration is modelled in SolidWorks software. Motion analysis is conducted in ADAMS software in order to compare the results obtained from the classical kinematics. Two types of model-based control schemes (namely Computed Torque Control and Proportional Derivative-Sliding Mode Control approach) with and without external disturbances are implemented to study trajectory tracking performance of the arm with different input trajectories. A disturbance observer model is employed in minimizing the tracking errors during the action of external disturbances such as joint friction and payload. In order to experimentally understand the inspection and replacement activities, a test set-up is developed using vision camera and microcontroller platform to guide the robot joint servos so as to perform defected object replacement activity. Presence of crack and the coordinate of the region are indicated with the use of image-processing operations. Using a high resolution Basler camera mounted at fixed distance from the tile surface, the surface images are acquired and image processing module identifies the crack details using edge detection algorithms. Necessary motion of the end-effector will be provided based on the pose calculations using coordinate transformations. Both visual inspection and joint guidance are combined in a single application and the results are presented with a test case of tile replacement activity. The results are presented sequentially using a test surface with uniform rectangular tiles

    Design and testing of a position adaptation system for KUKA robots using photoelectric sensors

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    This thesis presents the development and analysis of a position monitoring and adaptation system to be used in conjunction with a KUKA KR16-2 articulated robot using components readily available in most manufacturing settings. This system could be beneficial in the manufacturing sector in areas such as polymer welding and spray painting. In the former it could be used to maintain an effective distance between a welding end effector laying molten plastic and the surface area of the parts being welded, or in the case of the latter the system would be useful in painting objects of unknown shape or objects with unknown variations in the surface level. In the case of spray painting if you spray to close to an object you will get an inconsistent amount of paint applied to an area. This system would maintain the programmed distance between the robot system and target object. Typically, systems that achieve this level of control rely on expensive sensors such as force torque sensors. This research proposes to take the first step in trying to address the technical problems by introducing a novel way of adapting to a target surface deformation using comparably low cost photoelectric diffuse sensors. The key outcomes of this thesis can be found in the form of a software package to interface the photo-electric sensors to the KUKA robot system. This system is operated by a custom-built algorithm which is capable of dynamically calculating robot movements based off the sensor input. Additionally, an optimum system setup is developed with different configurations of sensor mounting and speeds of robot operation discussed and tested. The viability of the photo-electric diffuses sensors used in this application is also considered with further works suggested. Finally, a secondary application is developed for recording and analysing KUKA robot movements for use in other research activities

    ROBOT PROGRAMMING AND TRAJECTORY PLANNING USING AUGMENTED REALITY

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    Ph.DDOCTOR OF PHILOSOPH
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