| 1. |
- De Backer, Jeroen, 1987-, et al.
(författare)
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Investigation of path compensation methods for robotic friction stir welding
- 2012
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Ingår i: Industrial robot. - : Emerald Group Publishing Limited. - 0143-991X .- 1758-5791. ; 39:6, s. 601-608
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Tidskriftsartikel (refereegranskat)abstract
- Purpose – Friction stir welding (FSW) is a novel method for joining materials without using consumables and without melting the materials. The purpose of this paper is to present the state of the art in robotic FSW and outline important steps for its implementation in industry and specifically the automotive industry.Design/methodology/approach – This study focuses on the robot deflections during FSW, by relating process forces to the deviations from the programmed robot path and to the strength of the obtained joint. A robot adapted for the FSW process has been used in the experimental study. Two sensor-based methods are implemented to determine path deviations during test runs and the resulting welds were examined with respect to tensile strength and path deviation.Findings – It can be concluded that deflections must be compensated for in high strengths alloys. Several strategies can be applied including online sensing or compensation of the deflection in the robot program. The welding process was proven to be insensitive for small deviations and the presented path compensation methods are sufficient to obtain a strong and defect-free welding joint.Originality/value – This paper demonstrates the effect of FSW process forces on the robot, which is not found in literature. This is expected to contribute to the use of robots for FSW. The experiments were performed in a demonstrator facility which clearly showed the possibility of applying robotic FSW as a flexible industrial manufacturing process.
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| 2. |
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| 3. |
- Petterson, Anders, et al.
(författare)
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A Bernoulli principle gripper for handling of planar and 3D (food) products
- 2010
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Ingår i: Industrial robot. - : Emerald. - 0143-991X .- 1758-5791. ; 37:6, s. 518-526
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Purpose - The purpose of this paper is the increase the flexibility of robots used for handling of 3D (food) objects handling by the development and evaluation of a novel 3D Bernoulli gripper. Design/methodology/approach - A new gripper technology have been designed and evaluated. A deformable surface have been used to enable individual product handling. The lift force generated and the force exerted on the product during gripping is measured using a material tester instrument. Various products are tested with the gripper. A experimental/theoretical approach is used to explain the results. Findings - A deformable surface can be used to generate a lift force using the Bernoulli principle on 3D objects. Using a small forming a significant increase in the lift force generated is recorded. Increasing the forming further was shown to have little or even negative effects. The forces exerted on the product during forming was measured to be sufficiently low to avoid product damage. Research limitations/implications - To be able to improve the grippers lift strength a better model and understanding of the flow is needed. Originality/value - A novel Bernoulli gripper for 3D Bernoulli gripping have been designed and evaluated. The gripper enables flexible and delicate handling of various product shapes, 3D as well as 2D. Increased utilization of robots in the food industry can be gained. © Emerald Group Publishing Limited [ISSN 0143-991X].
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| 4. |
- Bolmsjö, Gunnar, et al.
(författare)
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Robotic arc welding - trends and developments for higher autonomy
- 2002
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Ingår i: Industrial Robot. - : Emerald. - 0143-991X. ; 29:2, s. 98-104
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Tidskriftsartikel (refereegranskat)abstract
- The development of robotized welding is truly impressive and is today one of the major application areas for industrial robots. The first industrial robots were introduced in the early 1960s for material transfer and machine tending. Not long after that, robots were used for spot welding and in the early 1970s for arc welding as well. During the years, significant developments have taken place both concerning the robot equipment and the welding equipment to meet the different challenges within the application area, This paper describes the development and progress of robotization in welding over the years and also some projections and trends for the near future.
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| 5. |
- Bolmsjö, Gunnar, et al.
(författare)
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Sensors in robotic arc welding to support small series production
- 2005
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Ingår i: Industrial Robot. - : Emerald. - 0143-991X. ; 32:4, s. 341-345
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Tidskriftsartikel (refereegranskat)abstract
- Purpose - Aims to present general concepts and framework for increasing the flexibility in robotic arc welding with respect to use of sensors and small series production. Design/methodology/approach - Presents a conceptual model with a framework that integrates existing tools and needed developments and research to increase the usefulness of sensors in robotic arc welding. The conceptual model is based on research within the field which covers supporting tools like robot simulation, sensor modelling and handling and optimization issues with respect to the robot task execution. A descriptive structure and concept is outlined to include welding procedure specifications (WPS) as a key module to provide an integrated and holistic control model of the robotic. Findings - Finds that the outlined conceptual model and architecture supports an increased flexibility of sensor controlled robots for arc welding applications. The arguments are specifically made for small series and one-off production. Research limitations/implications - The paper is limited to arc welding applications and the concept and arguments are made with small series and one-off production in mind. Practical implications - Increased use of sensors and robots in small series production. Originality/value - introduces a holistic approach for task level control of a robot which introduces a structured way for integrated and coordinated control of the arc welding task. The objective is to execute the welding task with maintained robustness with respect to predefined specifications (quality, productivity).
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| 6. |
- De Backer, Jeroen, 1987-, et al.
(författare)
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Deflection model for robotic friction stir welding
- 2014
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Ingår i: Industrial robot. - Bingley : Emerald Group Publishing Limited. - 0143-991X .- 1758-5791. ; 41:4, s. 365-372
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Tidskriftsartikel (refereegranskat)abstract
- This paper aims to present a deflection model to improve positional accuracy of industrial robots. Earlier studies have demonstrated the lack of accuracy of heavy-duty robots when exposed to high external forces. One application where the robot is pushed to its limits in terms of forces is friction stir welding (FSW). This process requires the robot to deliver forces of several kilonewtons causing deflections in the robot joints. Especially for robots with serial kinematics, these deflections will result in significant tool deviations, leading to inferior weld quality.This paper presents a kinematic deflection model, assuming a rigid link and flexible joint serial kinematics robot. As robotic FSW is a process which involves high external loads and a constant welding speed of usually below 50 mm/s, many of the dynamic effects are negligible. The model uses force feedback from a force sensor, embedded on the robot, and predicts the tool deviation, based on the measured external forces. The deviation is fed back to the robot controller and used for online path compensation.The model is verified by subjecting an FSW tool to an external load and moving it along a path, with and without deviation compensation. The measured tool deviation with compensation was within the allowable tolerance for FSW.The model can be applied to other robots with a force sensor.The presented deflection model is based on force feedback and can predict and compensate tool deviations online.
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| 7. |
- Fridenfalk, Mikael, et al.
(författare)
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Design and validation of a universal 6D seam tracking system in robotic welding based on laser scanning
- 2003
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Ingår i: Industrial Robot. - : Emerald. - 0143-991X. ; 30:5, s. 437-448
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the design and validation of a universal 6D seam tracking system that reduces the need of accurate robot trajectory programming and geometrical databases in robotic laser scanning. The 6D seam tracking system was developed in the flexible unified simulation environment, integrating software prototyping with mechanical virtual prototyping, based on physical experiments, The validation experiments showed that this system was both robust and reliable and should be able to manage a radius of curvature less than 200 mm. In the pre-scanning mode, a radius of curvature down to 2 mm was managed for pipe intersections an: 3 scans/mm, using a laser scanner with an accuracy of 0.015 mm.
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| 8. |
- Grahn, Sten, et al.
(författare)
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Spring-assisted gantry robots versus conventional gantry robots: spring constant optimization and work minimization
- 2002
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Ingår i: Industrial robot. - : Emerald. - 0143-991X .- 1758-5791. ; 29:1, s. 53-60
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Tidskriftsartikel (refereegranskat)abstract
- The spring-assisted gantry robots, described in this paper, were designed primarily for the rapid transfer of lightweight objects from one point to another, e.g. to pick objects from a conveyor belt and to place them in a box. The average amount of work required for pick-and-place operations carried out by a conventional gantry robot was decided. Springs were added to conserve the kinetic energy of the main bar, which slides in the X-direction and the work of the same pick-and-place operation was decided. A theoretical study showed that when the spring constant was optimized the required motor work of the spring-assisted robots were 42-95 percent less than the required work of the conventional robot. The conceptual robot exists in mathematical models in Matlab and SIMULINK.
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| 9. |
- Hellström, Thomas, et al.
(författare)
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A software framework for agricultural and forestry robots
- 2013
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Ingår i: Industrial robot. - : Emerald Group Publishing Limited. - 0143-991X .- 1758-5791. ; 40:1, s. 20-26
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The purpose of this paper is to describe a generic software framework for development of agricultural and forestry robots. The primary goal is to provide generic high-level functionality and to encourage distributed and structured programming, thus leading to faster and simplified development of robots. A secondary goal is to investigate the value of several architecture views when describing different software aspects of a robotics system.Design/methodology/approach: The framework is constructed with a hybrid robot architecture, with a static state machine that implements a flow diagram describing each specific robot. Furthermore, generic modules for GUI, resource management, performance monitoring, and error handling are included. The framework is described with logical, development, process, and physical architecture views.Findings: The multiple architecture views provide complementary information that is valuable both during and after the design phase. The framework has been shown to be efficient and time saving when integrating work by several partners in several robotics projects. Although the framework is guided by the specific needs of harvesting agricultural robots, the result is believed to be of general value for development also of other types of robots.Originality/value: In this paper, the authors present a novel generic framework for development of agricultural and forestry robots. The robot architecture uses a state machine as replacement for the planner commonly found in other hybrid architectures. The framework is described with multiple architecture views.
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| 10. |
- Johansson, Rolf, et al.
(författare)
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Sensor Integration in Task-level Programming and Industrial Robotic Task Execution Control
- 2004
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Ingår i: Industrial Robot. - : Emerald. - 0143-991X. ; 31:3, s. 284-296
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Tidskriftsartikel (refereegranskat)abstract
- Presents an approach to improved performance and flexibility in industrial robotics by means of sensor integration and feedback control in task-level programming and task execution. Also presents feasibility studies in support of the ideas. Discusses some solutions to the problem using six degrees of freedom force control together with the ABB S4CPlus system as an illustrative example. Consider various problems in the design of an open sensor interface for industrial robotics and discusses possible solutions. Finally, presents experimental results from industrial force controlled grinding.
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